LIBRARY UNIVERSITY OF CALIFORNIA. Class HAND-BOOK OF American Gas-Engineering Practice BY M. NISBET-LATTA j* MEMBER AMERICAN GAS INSTITUTE MEMBER AMERICAN SOCIETY OF MECHANICAL ENGINEERS NEW YORK D. VAN NOSTRAND COMPANY 23 MURRAY AND 27 WARREN STREETS 1907 GENERAL Copyright, 1907 BY IX VAN NOSTRAND COMPANY PREFACE. AMERICAN gas engineers have for a long time deplored the lack of a work treating on the technology of modern gas supplies from a practical standpoint, and framed in such a manner as to constitute a book of reference for those engaged in the industry, as well as for students. To supply his personal needs, the author began, several years ago, a compilation of material which, accumulating and being classified, has taken the shape of the handbook which he now presents to the profession, with every confidence that it will prove of value and be welcomed. His intention is to extend and revise future editions so that the final result will be a complete hand- book of gas engineering, covering the minute details of every branch of the industry. The general plan of the work is as follows: Water-gas manufacture, from the consideration of the fuels and materials to the gas-holder. The treatment is throughout practical rather than theoretical, and the chapters on these sub- jects would be understandingly read by gas-makers, foremen, and manual operators of the works, a feature which the author con- siders of considerable importance. Much of such practical detail of operation has not heretofore been published. The next division is devoted to gas distribution, which is gone into at Isn^h. It includes also a discussion of the various gas-burning appliances and their attendant data, the whole treated in the same practical way as the chapters on manufacture. iii 207115 iv PREFACE. Other methods of gas manufacture are reserved for subsequent editions, but distribution as here treated is applicable to every field of gas engineering. Specifications for mains, joints, piping, and standard sections will be found of peculiar interest and con- venience. The final division on technical data contains much theoretical, mathematical, and technical information on the properties of gases and steam, calorific values, temperature data, testing corrections, tables, etc. The sources of this data have been carefully con- sidered and are believed to be reliable. The subject of proprietary patents and apparatus not in general use were, for lack of space, omitted, which fact also prevented the including of many things which would have been of interest, these also being left for future editions. The author depends on the readers of this handbook for mate- rial assistance in improving its present form and extending its usefulness, and welcomes any suggestions and criticisms of his readers that may enable him to keep the ensuing editions abreast of the progress of the industry. The author desires to acknowledge the assistance of the many engineers connected with gas companies and manufacturing con- cerns. The uniform courtesy with which the author's requests for information have been invariably met is a source of much gratifi- cation to him, and he desires to here express his great appreciation. M. NISBET LATTA. NEW YORK, August, 1907. CONTENTS. PART I. WATER-GAS MANUFACTURE. CHAPTER I. THE GENERATOR. PAGE APPARATUS 1 FUELS, OIL 2 BLASTING 3 BLOWERS 4 BLAST PRESSURED 5, 26 CLINKER GENERATOR STEAM 6 STEAM FLOW 9 STEAM SUPPLY 11 QUALITY OF STEAM 12 BARREL CALORIMETER 43 THROTTLING CALORIMETER 14 GENERATOR DETAILS 17 GENERATOR OPERATION 18 FUELS COMPARED 19 CARBON DIOXIDE 22 GENERATOR LINING : 25 REPAIRING CEMENTS 26 SAFETY DEVICES 27 FIRE-BRICK 27 FIRE-CLAY ANALYSIS 31 CHAPTER II. THE CARBURETTER. BRICKWORK 36 CHECKER-BRICK SPACING 37 OIL SUPPLY , 39 v TO CONTENTS. PAGE OIL-PUMP 41 OIL STORAGE 42 GRADES OF OIL 43 OIL ANALYSIS 44 TEMPERATURES 49 GAS-MAKING VALUE OF OILS 50 OPERATION DETAILS . . 51 CHAPTER III. THE SUPERHEATER. TEMPERATURES 53 CARBON DEPOSITS 54 SUPERHEATER BRICK 55 CHAPTER IV. WASH-BOX AND TAR. CLEANING 56 OPERATION DETAILS 57 COMPOSITION OF TAR 58 TAR PAINT AND PAVING 59 TAR-PUMPS 60 SEPARATION * 61 BURNING TAR 62 CHAPTER V. SCRUBBERS. OPERATION DETAILS 64 TRAYS 64 SPRAYS 65 WATER ANALYSIS 66 CHAPTER VI. CONDENSERS. TEMPERATURES 67 SURFACE 68 ESSENTIAL PRINCIPLES 69 CHAPTER VII. PURIFIERS. TESTING FOR IMPURITIES 72 SULPHUR REMOVAL 73 PURIFYING MATERIAL 74 CAPACITIES OF PURIFIERS 74 MAKING OXIDE 77 CONTENTS. vii PAGE PREPARING LIME 78 CALCULATIONS 79 TEMPERATURE 81 TESTING OXIDE BOXES 81 REVIVIFICATION 82 REMOVING SULPHUR TRACES 85 ANALYSIS FOR TOTAL SULPHUR 86 JAEGER GRIDS 90 CHAPTER VIII. EXHAUSTERS. POWER REQUIRED 92 INSTALLATION 94 OPERATION 94 LOSSES 95 SLIP 96 AIR-COMPRESSOR CAPACITY 99 CAPACITY OF GAS-EXHAUSTERS 100 TABLES SHOWING EFFECT OF COMPRESSION . . . 103 CHAPTER IX. STATION-METERS. SIZES 112 CONNECTIONS 113 VOLUME CORRECTION 115 STANDARD UNIT OF VOLUME 117 OPERATION HINTS 118 ROTARY METERS 119 CHAPTER X. HOLDERS. PRESSURE 122 FREEZING OF TANKS 124 CLEANING TANKS 125 PATCHING HOLDERS 125 CAPACITY 127 WIND PRESSURE 129 VARIOUS DETAILS 130 CHAPTER XI. DETAILS OF WORKS OPERATION. QUALITY OF GAS 131 OPERATION RECORDS 132 FLOW OF WATER . . .133 viii CONTENTS. PART II. GAS DISTRIBUTION. CHAPTER XII. NAPHTHALENE. FAOB PROPERTIES 135 DEPOSITS 136 REMOVING DEPOSITS T 137 PREVENTING DEPOSITS 139 CONTINUOUS TEST : 141 CHAPTER XIII. MAINS. CAPACITY 142 LAYING MAINS 143 GRADIENT 144 PIPE-JOINT SPECIFICATIONS 145 CEMENT PIPE-JOINTS 148 LEAD PIPE-JOINTS 150 ADVANTAGES OF VARIOUS JOINTS 152 HIGH-PRESSURE PIPE-JOINTS 154 CAPACITY REDUCED BY VALVES 159 PRESSURE REGULATORS 159 DRIPS, ANCHORS, AND TESTING 160 PIPE DEPOSITS 161 LEAKS, TESTING FOR 162 RECORDS OF MAINS AND SERVICES 163 SERVICE CONNECTIONS 163 REPAIRING BREAKS 166 MAIN-STOPPERS 167 COST OF INSTALLING MAINS 168 COST OF HANDLING PIPE 168 COST OF TRENCHING 169 COST OF LAYING PIPE 175 COST OF SUBAQUEOUS MAINS 177 PIPE-JOINTS OF LEAD WOOL 180 SPECIAL CASTINGS FOR MAINS 182 CHAPTER XIV. SERVICES. SIZES 200 TAPPING FOR 200 COATING, PROTECTIVE 201 FREEZING 202 FORCING-JACKS .......... T . t ... T . t . T ..... t 203 CONTENTS. ix PAGE HIGH-PRESSURE FITTINGS 203 DIMENSIONS FOR SERVICE-PIPE 204 HIGH-PRESSURE MAIN TAPPING 205 HIGH-PRESSURE SERVICE CONNECTIONS 208 CHAPTER XV. CONSUMERS' METERS. TESTING METERS 209 CAPACITY RATING 210 CONNECTIONS 211 COMPLAINT AND TEST METERS 212 METER-TESTING CORRECTIONS 215 CHAPTER XVI. PRESSURE. ADEQUATE PRESSURE 216 GOVERNORS 218 PRESSURE-GAGES, DIFFERENTIAL 219 PITOT-TUBE MEASUREMENTS 220 ENGINE PULSATIONS IN SUPPLY 223 HIGH PRESSURE, FLOW FORMULA 224 COMPRESSION OF AIR 225 COMPRESSION, EFFECT OF, ON GAS 226 PRESSURE CONVERSION TABLES 228 PRESSURE STORAGE-TANKS 229 CAPACITY OF PIPES AT VARIOUS PRESSURES 231 POLE'S FORMULA FOR PIPE CAPACITY 232 COMPARISON OF GAS-FLOW FORMULA 235 CHAPTER XVII. HOUSE PIPING. SPECIFICATIONS 236 METERS 237 REQUIREMENTS FOR GAS FIXTURES 238 CAPACITY OF PIPE 240, 247 CONCEALED PIPING 244 PIPE CEMENT 248 CHAPTER XVIII. APPLIANCES. GAS RANGES AND HEATERS 249 TEST FOR EFFICIENCY 249 BURNERS 250 PIPING 251 HEAT INSULATION 252 x CONTENTS. PAGE GAS CONSUMED 253 BAKING 253 ESSENTIALS 254 COMBUSTION 255 RANGE COCKS 255 TESTING RANGES < 256 RANGE SPECIFICATIONS 259 LIGHTING APPLIANCES, BURNERS '. 260 CANDLE-POWER AND HEAT VALUE 260 HEAT REQUIREMENT FOR MANTLE BURNERS 261 FLAT-FLAME BURNERS 262 INDUSTRIAL APPLIANCES, OPERATION 264 CONSUMPTION BY VARIOUS APPLIANCES 265 GAS-ENGINES . . ... 266 PART III. GENERAL TECHNICAL DATA. CHAPTER XIX. PROPERTIES OF GASES. COMPOSITION 267 VOLUME, EXPANSION LAWS 271 AQUEOUS VAPOR CORRECTIONS 275, 279 BAROMETRIC CORRECTIONS i 276 SPECIFIC GRAVITY DETERMINATION 281 SPECIFIC GRAVITY OF OILS 285 SPECIFIC HEAT OF GASES AND SOLIDS 287 CALORIFIC VALUE OF GASES 291 JUNKER CALORIMETER 292 SlMMANCE-ABADY GAS-CALORIMETER 299 TEMPERATURE PROPERTIES 302 MELTING-POINTS 304, 307 OPTICAL PYROMETER, THE LUNETTE 305 UNITS OF HEAT AND TEMPERATURE 306 INDUSTRIAL OPERATION TEMPERATURES 307 HEAT RADIATION AND CONDUCTION 308 CHAPTER XX. STEAM. PROPERTIES OF STEAM 311 WORK IN STEAM 318 EXPANSION CURVES 320 SATURATED-STEAM TABLES 323 STEAM-BOILER PRACTICE 325 CONTENTS. XI PAGE VALUE OF BOILER-FUELS 327 WATER SUPPLY FOR BOILERS 327 CHIMNEYS, DRAUGHT AND DIMENSIONS 332 FLUE AREAS 337 CHAPTER XXI. MATHEMATICAL TABLES. CIRCLES, POWERS, AND ROOTS 341, 357 DECIMAL EQUIVALENTS OF AN INCH 352 LOGARITHMS OF CONSTANTS 352 LOGARITHMS OF NUMBERS 354 CAPACITY TABLES OF VESSELS IN GALLONS 360 AREAS OF SEMI-SQUARES 364 CHAPTER XXII. CONVERSION FACTORS. FRENCH AND ENGLISH UNITS 368 CONVERSION OF HEAT- UNITS 371 CONVERSION OF TEMPERATURES 373 FACTORS CONCERNING WATER 376 CHAPTER XXIII. PIPE AND MISCELLANEOUS DATA. CAPACITY OF IRON PIPE . . . : 377 QUALITY OF FITTINGS 380 DIMENSIONS AND WEIGHTS 383 LEAD-PIPE DIMENSIONS 389 RIVETING OF PLATES 392 DRILLS AND TAPS 399 MISCELLANEOUS INFORMATION 401 SPECIFICATIONS FOR PIPE AND SPECIALS 414 STANDARDS FOR PIPE AND SPECIALS 421 METHOD FOR " CUTTING-IN " SPECIALS 451 FLEXIBLE-JOINT PIPE 453 TOOLS FOR LAYING CAST-IRON PIPE 456 SIZES OF PURIFYING-BOXES 460 AMERICAN GAS-ENGINEERING PRACTICE. PART I. WATER-GAS MANUFACTURE. CHAPTER I. THE GENERATOR. THE burden of this work will bear upon water-gas as manu- factured by the Lowe process, taking up the work in the sequence of manufacture and tracing the course of the gas throughout the operation. Apparatus. The apparatus used is principally of the Lowe type, consisting of a generating vessel, carburetter, superheater, wash-box, condenser and scrubber, relief-holder, exhauster, puri- fier, and holder. These water-gas machines are compact and the vessels are side by side in one building. The following table shows the sizes and capacities of the standard Lowe process water-gas apparatus as manufactured by the United Gas Improvement Co., the largest water-gas apparatus manufacturers in the world: WATER-GAS APPARATUS (U. G. I. CO.). Double Superheater, Diameter Generator Carburetter, Diameter Generator, Diameter Feet. Carburetter, Diameter Feet. Superheater, Diameter Feet. Daily Capacity, Cubic Feet per 24 Hours. Feet. Feet. 3 3 3 50,000 4 4 4 100,000 4 4 4 125,000 5 . 5 5 5 250,000 6 6 6 6 400,000 6.5 , 7.5 7 7 750,000 8.5 t 8.5 8 8 1,000,000 9 9 9 9 1,250,000 11 11 11 11 2,000,000 AMERICAN GAS-ENGINEERING PRACTICE. Another variation of this type is made by the Gas Machinery Co., who issue the following table of sizes. These capacities are approximate only, as the actual amount of gas which can econom- ically be made in a carburetted water-gas apparatus depends upon the kind of fuel and oil used, blast pressure, steam supply, candle power desired, etc. WATER-GAS APPARATUS (GAS MACHINERY CO.). Diameter of Generator Shell, Feet. Height of Operating Floor, Ft. Ins. Capacity in 24 Cubic Feet per Hours. Size of Building Suitable for Two Sets, Usual Height of Building to Bottom of Roof-trusses, Feet. Feet. 3.5 12 3 60,000 to 75,000 23X30 20 4 13 3 100,000 125,000 24X32 22 5 13 3 175,000 250,000 27X40 25 6 14 3 325,000 425,000 30X46 28 7 14 3 500,000 650,000 33X52 30 8 14 3 750,000 900,000 36X56 30 9 15 3 1,000,000 1,250,000 38X64 30 10 16 3 1,300,000 1,600,000 42X78 32 11 16 3 1,600,000 1,900,000 48X84 32 Fuels. Generator fuels are generally of two kinds: coal (anthracite) and what is generally known as 48-hour oven coke. The best results from either of these are generally obtained from a glossy black coal, egg-size and passing through about a 3-inc'h- mesh screen, or from a silvery-gray coke of about the same diam- eter. The chief defect which the coal may possess lies in the amount of sulphur which it contains, a large percentage of sulphur producing not only a very sulphurous gas, but also forming a hard and intractable clinker. " Twenty-four-hour gas-house coke " is sometimes used in emergency, but coke of this class is usually too soft and does not retain the heat in the generator while steam is blown through it during the " run," thereby creating a strongly acid gas. Oil. It is the custom of a number of companies throughout the country to introduce the oil used for enriching the water-gas directly into the generator on all up-runs. This is supposed to save the brick of the carburetter, and, inasmuch as the oil is vaporized at the same heat and under the same conditions under which the steam is decomposed, the vapor tension is assumed to be approximately the same, and the oil-gas and water-gas being thus combined under similar conditions at an equal temperature form a more intimate mixture. In addition to this, when the THE GENERATOR. 3 gases are formed in the generator the carburetter is saved the chilling effect due to vaporizing the oil, and is thus utilized as an additional superheating chamber, providing for the gases an extraor- dinary amount of fixing surface and prolonging the period of fixation travel. Practice differs very greatly in regard to this method of work- ing. It is certain, however, that in small works occasional use of this method is of advantage, inasmuch as it not only relieves the carburetter of the immediate vaporization of the oil, but allows any carbon which may have already accumulated upon the brick- work of the carburetter to burn off. There should be, at least in all small works where continuous running is a necessity and any delay caused by stoppage of the oil-spray is a serious contin- gency, a flexible connection with the oil-pipe which can be attached to a spray tapped into the lid of the generator coaling- valve cover. Where oil is used to substitute solid fuel in manufacturing water-gas, the amount necessary, using crude oil as a basis, is variously estimated at from 12 to 15 gallons per 1000 cu. ft. At least one-third of this oil is consumed for the heating (or during the blasting period) of the apparatus. Blasting. The question of the coaling periodicity is one over which there is considerable diversity of opinion. It should un- doubtedly depend upon the condition of the incandescent fuel- bed and be determined by the gas-maker. The fires should be thoroughly cleaned and freed of all possible clinker at least twice a day. In blowing air through the fuel-bed during the first blast- ing, in putting a generator in operation, many analyses of gas show that it is a rare thing for the generator fire to be thoroughly in condition for the first run, the result invariably showing large quantities of carbon dioxide, and going to prove that the dura- tion of the blast was too short. The author has indeed never known a gas-maker who was sufficiently careful when getting up this first heat, and especially recommends that before turning on steam the coaling-valve be opened and the fire examined to see that there is no " green" coal visible which has not attained the proper heat, and that the generator fuel-bed has a temperature corresponding to a bright orange color. Gas-makers are often prevented from suffi- ciently blasting their generators for fear of overheating the other chambers. It is better to operate with a light blast for a longer period through the generator than with a strong blast for a shorter time, and under some conditions it has been advisable to put a light blast through the generator with the coaling-valve remain- ing open. Should, however, the carburetter become unduly hot AMERICAN GAS-ENGINEERING PRACTICE. during this blasting period it may be " blown cold" by an exces- sive blast through the carburetter while a light generator blast is maintained. There cannot be too much emphasis laid upon the proper heat being obtained in the generator before the commencement of runs, as insufficient heat and improper decomposition of the steam, together with the chilling effect of " green " or insuffi- ciently heated coal, will invariably produce an excess of oxygen, while the carbon, unless incandescent, fails to combine, thereby forming carbon dioxide instead of the desired monoxide. Blowers. Blowers should be of ample capacity and if pos- sible in duplicate. The location of a blower should be removed as far as possible from dust, as its bearings at high speeds require close attention and should be kept in the very best con- dition, their oilways being examined periodically, for they may perhaps be termed the " critical point " of the works. It is some- times necessary, in case of their heating, to play a small stream of water upon them; ice may be of advantage; cylinder-oil, castor- oil, or even urine is used, the latter being employed with most remarkable results, as the salts therein contained crystallize in the heat and form a viscous bearing between the shaft and the box. Dixon's graphite compounds are also valuable. The following table gives the principal dimensions to be speci- fied in securing a blower of the Sturtevant type for supplying air- blast to water-gas generators; they are special extra heavy: DIMENSIONS OF BLOWERS. Maximum Blower on Adjustable Bed Pressure. with Sliding Outlet. Diameter Maxi- Blower Number of Blower. and Face of Pulley in Inches. mum Revolu- tions per Minute. Ounces per Square Inch. Inches of Water. only. Outside Diameter of Outlet in Inches. Outside Diameter Outlet with Horizontal Discharge Dimensions of Oblong Pipe Connection for Up-blast Discharge in in Inches. Inches. 4 5X 7 3,670 12 20.8 10f Hf 10fXl5f 5 7X 8 3,420 14 24.2 12 1*1 12iXl8t 6 8X9 3,330 16 27.7 14 16} 14fx21f 7 9X11 2,750 16 27.7 16 171 16|X24f 8 10X13 2,270 16 27.7 ISj 20f 18|X27| 9 12X15 2,040 16 27.7 21 23i 21fX32 10 14X16 1,700 16 27.7 24 25| 24|X36| NOTE. These Sturtevant special extra-heavy blowers are for supplying blast to water- gas generators. THE GENERATOR. 5 The outside dimensions of the shells of these blowers are the same as those of the ordinary gas-blowers given in Catalogue No. 82, but the pulleys are larger and the hangers or supports for the bearings are longer. Bearings of the blower or engine, where made of babbitt metal, should be made at a single pouring of the metal, no interval being allowed. After being poured, the bearing should be heavily peened, this having a tendency to make the metal in the bearing more homogeneous. Where engine or blower bearings have a tendency to run hot, cylinder-oil or, better, castor-oil may be temporarily used. At the first opportunity, however, the bear- ings should be opened and the oil-ducts examined. Generator Blast Pressures. The difference in pressure between the top and bottom of a water-gas generator having a 6 to 7 ft. deep fuel-bed will vary from 5 in. to 8 in., depending upon the nature of the fuel used and the heat in the machine. Six inches pressure is a good average, while a lesser difference than 5 in. tends to show a lack of even distribution on the part of the fire-bed, the presence of blow-holes, etc. High blast pressure has a tendency to increase clinkers; when necessary this may be counteracted by alternating or reversing the steam in the middle of each run. Too much stress cannot be laid upon the necessity for a thorough cleaning of the fire, a neglect of this, more than any other feature, tending toward clinker forma- tion. Where generators are intermittently in service they should be gradually brought up to their heat, the increase in temperature being by slow degrees and not forced. From a standpoint of pro- duction it is not good practice to vary the direction of steam during a run, except in instances of excessive clinker formation, greater production being obtained per hour by varying the alternate runs by a down-run every third or fourth time. Where fan-blowers are driven by electricity common practice demands a consumption of about 1 k.w. per 1000 cu. ft. of gas manufactured. Regarding the pressure of blast to be maintained upon the generator of water-gas sets, the following theory has been the result of a number of experiments by the author: A medium blast pressure should as nearly as possible be main- tained because, should the blast pressure increase above about 18 in., combustion of fuel becomes too rapid, producing too much heat and too rapid consumption of fuel, together with clinker. Should the^blast pressure fall below the minimum, about 12 in. of water, the following phenomena will be observed: The rate of flow of the blast being insufficient in pressure to carry away from the generator the CO first produced by com bus- AMERICAN GAS-ENGINEERING PRACTICE. tion, and which should be burned to CO 2 by the additional air supply provided at the carburetter and superheater, furnishing fuel respectively to these parts of the apparatus, a large portion of this product remains inertly in the generator and is gradually burned from CO to CO 2 , or, in other words, the complete com- bustion of C to CO 2 takes place in the generator instead of being distributed throughout the apparatus. Primary combustion should take place in the generator, and secondary combustion in the two machines following in series. The result of this additional combustion is the production of excessive heat in the generator, greatly deteriorating the lining, etc., and at the same time causes a failure on the part of the gen- erator to supply sufficient gas for the secondary combustion of the other machines. When the blast pressure is ample these gases are kept moving and carried along^by the draught, and are in due pro- cess consumed. The capacity of the generator is usually rated from the area of the grate, being generally figured approximately at 20,000 cubic feet per square foot of grate surface per 24 hours. It is recommended in all instances to run the steam-pipe to the generator, of a size not smaller than 1.5 in. diameter, reducing it at the generator inlet by. a J-in. valve. Clinker. A word may be said here concerning one of the greatest annoyances to the gas-maker, as well as hindrance to obtaining good results the formation of clinker, which occurs especially with highly sulphurous coals and is at times almost im- possible to control. Besides the use of heavy clinkering-bars, long- handle cold chisels, and sledges, there are numerous chemical com- pounds used for clinker disintegration. Oyster-shells and unslaked lime are used for this purpose in a large number of works, but are not especially efficacious. Perhaps one of the surest methods is that of leaving the steam turned on upon the bottom of the gen- erator with the valve opened, say, a quarter of a turn. This method, if pursued for ten or twelve hours, invariably softens the clinker and is generally known as "rotting." Its one objection is the softening and decomposition of the fire-brick. The author suggests a method having none of these disadvan- tages and which he has used with invariable success. On the end of a pipe of about f in. diameter and 12 or 15 ft. in length he affixes a funnel, places the end of the pipe upon a clinker, where it joins the fire-brick and pours through the funnel a mixture of 12 pints of water and 1 of common vinegar, moving the pipe about to attack various points of the clinker and repeating the pouring, when it becomes soft enough to yield to a heavy clinker-bar. Generator Steam. It has been generally agreed that the temperature of the fire, which should be at least 1800 F., and the THE GENERATOR. 7 control of the rate of flow of the steam determine the composition of the gas within the limits usually applied to water-gas practice. It is doubtless nearly correct to assume the amount of steam dis- sociated as about 15.4 or 15.5 Ibs. per 1000 cu. ft. of final gas. The steam should unquestionably be as dry as possible, and for this purpose the initial boiler pressure should be not lower than 90 and not exceeding 120 Ibs. All steam-piping should be cov- ered, preferably with magnesia covering. A separator should be placed near the entrance of the generator, an extremely satisfactory kind of which is the Cochrane horizontal type; connected with this, the Bundy steam-trap has given the author the best results. This trap is perfectly automatic, easily adjusted, and operates with a balance-arm; one alone will take care of the water from a half-dozen or more separators about the works and, if placed at the proper elevation, will return condensation into the boiler. One of the greatest difficulties in the manufacture of gas is the proper regulation of the amount of steam to be admitted into the generator. Too little steam retards gas production or limits the amount of gas made by the generator, while an excess of steam carries off and wastes an enormous amount of heat from the gen- erator fire, the exact amount depending upon the temperature of the gas when leaving the superheater. For example, suppose the steam entered the generator at 331 F. and the gas left the super- heater at 1450 F., then each pound of undecomposed steam car- ried from the superheater about 537 B.t.u. Assuming the quantity of waste steam to amount (as has been cited in an experiment by Mr. Morris) to 14.8 Ibs. per 1000 cu. ft. of gas, the waste heat per 1000 cu. ft. manufactured would amount to nearly 8000 B.t.u., or about one-half of the total energy required for the decomposing of the steam in the finished gas. Too little steam will leave the fire in a condition favorable to the formation of hard and obdurate clinker, greatly increasing the length of the necessary cleaning period and reducing materi- ally the gas made per day for the apparatus, and destroying the linings. The quantity of excess steam (steam admitted to the generator and not decomposed) is best determined by an analysis of the gas for CO 2 , the amount of carbonic acid gas being in direct ratio to the excess of steam. To determine the rate of flow of steam admitted to the genera- tor satisfactory use may be made of the following device. The steam-pipe is disconnected from the generator shell and immersed in a cask containing a known .weight of water, the cask being set upon portable scales, so that the steam-pipe dips into the water the number of inches corresponding to the gas pressure in the 8 AMERICAN GAS-ENGINEERING PRACTICE. generator when and where the steam is admitted. The total length of steam-piping and total length of turns are the same as when the pipe is connected to the generator, and the quantity of steam flowing into the cask per unit of time is read on the scale- beam. Separate determinations are made of the steam supplies at the upper and lower connections to the generator. The rates thus found may be taken as approximately correct for conditions of actual generator use. Under operating conditions the use of the Sargent Steam Meter will be found very convenient for current reference, and as a standard of comparison and of operation. This meter is tested and calibrated with commercially dry steam containing about 2% of moisture, and of course any varia- tion in this moisture shows up as an error. To all practical pur- poses however, allowing for the personal error possible in obser- vation, under any ordinary conditions of operation, the maxi- mum variation of this meter does not exceed 3%, which is near enough to furnish a very satisfactory standard of operation and comparison. The operation of the meter is as follows: When no steam is flowing through the pipe the mercury in the cistern and in the tube is on a level, that in the tube registering zero. The steam beginning to flow, its velocity places a pressure upon the cistern, causing the mercury to rise in the tube in direct ratio to said velocity and proportionate to the weight flowing through. To read the meter: Note the pressure on the gauge, revolve the drum containing the dial, by the hand-wheel, until the pres- sure on the top of the drum corresponding to the gauge is behind the tube, then the top of the column of mercury will indicate the pounds of steam or horse-power flowing through per unit of time. The quantity of steam decomposed, and so present in the finished gas, is determined from an analysis of the gas, the water- vapor present in the finished gas being dependent upon the tem- perature. A direct measure of the excess steam used per 1000 cu. ft. of gas made is effected by collecting all the condensation (tar and water) that occurs. If no water is introduced into the system between the carburetter and the gas-holder, the water condensed and measured gives directly the data for the excess steam used in the generator. This figure is one most easily and accurately ascer- tained, and it furnishes a constant check upon the operation of the generator. It is needless to point out that wet steam carrying with it water in the form of fog would largely increase the oxygen factor THE GENERATOR. 9 in the gas, thereby running up the production of CO2. To over- come this it is necessary, as before stated, to procure the dryest possible steam by using pipe coverings, steam separators, and a high initial boiler pressure. On the other hand this boiler pressure has certain drawbacks, of which rapidity of flow of the steam through the incandescent carbon is the chief. Too great a velocity will produce blow-holes or open channels through the carbon bed and cause the steam to escape undecomposed, as well as an uneven distribution of steam throughout the fuel-bed, which, for the best results, should be as uniform as possible. To overcome these diffi- culties it has occurred to the writer to place a reduc ing-valve (such as the Mason type) on the steam-pipe just prior to its admission into the separator; such a valve will reduce a pressure of about 100 Ibs. at the boiler to a terminal pressure of 45 or 50 Ibs. in the generator, which would materially reduce the velocity of flow and tend to superheat. It has also occurred to the writer that it might be well to intro- duce the steam into the generator by a number of small jets similar to the radial sprays on scrubbers, which would distribute the steam more generally over the cross-section of the generator. He has, however, no information as to any such experiment having ever been made. However, it is well known in gas manufacture that decreasing velocity of gas flow increases the intimate union and thorough combination of the substances involved. It is needless to point out the necessity of having extra-heavy pipe and heavy brass fittings on all steam connections. In the case of both oil and steam connections the author has had specially good service from Lunkenheimer valves. Between the generator and the carburetter asbestos-board gaskets should be used in the connections, and for these and other packings there is none better than Vulcabeston. Steam Flow. Drs. Strache and R. Jahoda, in their work on the " Theory of the Water-gas Process/' place great emphasis on the rate of flow of the steam, and imply that Dr. Bunte in his work did not properly appreciate the. result that different rates of flow would have upon the gas made thereby. Among other remarks they write as follows: That at a particular temperature both the steam passing through undecomposed and the proportion of car- bonic acid in the gas largely increase with the increase in the rate of the steam flow, and also increase in direct ratio. Secondly, that, a constant rate of flow of the steam being secured, both the CO 2 and the steam excess decrease with an increase of tempera- ture. That at low temperature the CO 2 and the excess may be reduced by reducing tbe rate of flow of the steam. In verification of the above they give the following table: 10 AMERICAN GAS-ENGINEERING PRACTICE. Rate of Flow of Steam. Hinute of Run at which Ob- servation was Made. Temper- ature of Generator, Deg. C. Temper- ature of Effluent Gas, Deg. C. Unde- composed Steam, Percent- age of Total. Carbonic Acid Gas, Per Cent. Efficiency of Run, Per Cent, of Maxi- mum. Total Efficiency, Per Cent, of Maxi- mum. 0.58 2 790 228 1.3 7.1 5 788 207 2.7 4.6 69^6 54.5 12 785 214 9.1 6.2 67.0 53.0 20 778 221 21.8 8.9 60.5 47.0 35 740 200 48.8 13.0 42.0 33.0 4.40 1 860 390 4.0 2.2 92.0 75.0 3 850 390 10.0 2.7 91.0 74.0 6 816 365 22.0 4.5 90.0 75.0 9 810 365 24.0 6.6 88.0 73.5 12 796 408 28.0 8.7 86.3 71.8 16 775 415 45.5 11.4 83.5 71.0 7.50 1 530 2.7 3 515 11.7 4.6 90'6 69^6 6 490 27.4 9.6 88.0 70.5 9 470 54.2 12.6 78.0 63.0 12 470 62.1 15.6 73.0 59.0 8.10 1 515 3.4 3 510 'l'.3 5.5 9i"o 71.0 6 . 500 19.7 11.2 88.0 70.0 9 . 475 14.9 86.0 71.0 12 470 47'.9 17.3 82.0 68.0 13.00 1 470 7.6 3.4 92.0 73.5 5 500 11.9 5.6 91 .5 73.0 6 500 32.1 9.0 92.0 71.5 13.40 1 900 470 14.3 5.0 91.5 72.5 3 8$0 478 27.9 6.9 89.0 71.0 6 830 475 48.9 9.4 84.0 67.5 9 800 493 62.8 13.1 77.0 62.5 12 780 492 69.6 13.9 74.0 60.0 17.00 1 600 8.1 2.6 91.0 69.0 3 590 25.8 5.3 88.0 67.0 6 560 48.5 11.8 81.0 62.0 10 540 73.6 14.9 67.5 51.0 12 530 76.5 15.2 65.0 51.0 21.20 1 945 680 8.6 4.4 90.5 70.5 3 910 650 41.3 6.8 83.0 63.0 6 865 620 48.6 8.7 81.0 61.5 12 805 590 70.1 14.4 68.5 53.5 16 780 77.6 17.6 61.5 47.0 21.30 1 680 2.1 3 650 23^0 6.0 90'.0 70'.5 6 620 63.3 11.8 72.5 54.0 10 ... 595 77.1 14.8 61.5 46.0 THE GENERATOR. 11 The researches of Harris under the direction of Dr. Bunte were tabulated as follows: Temperature, Composition of Gas, Volumes Per Cent. Water-vapor, Per Cent. Degrees C. H CO. C0 2 . Decomposed. Undecomposed . 694 65.2 4.9 29.8 8.8 91.2 758 65.2 7.8 27.0 25.3 74.7 838 62.4 13.1 24.5 34.7 65.3 838 61.9 15.1 22.9 41.0 59.0 861 59.9 18.1 21.9 48.2 51.8 954 53.3 39.3 6.8 70.2 27.2 1010 48.8 49.7 1.5 94.0 6.0 1060 50.7 48.0 1.3 93.0 7.0 1127 50.9 48.5 0.6 99.4 0.6 Steam Supply. Steam should never be turned on the gen- erator for a " run " until the top of the fire appears to be in a thorough state of combustion and free from dark (or " green ") coal, as viewed through the sight-cock in the coaling-lid of the generator. Excessive heat in the generator, and indirectly the entire set, may be speedily " killed " by adding, in addition to the regular up-steam on an up-run, say a quarter of a turn of opening on the down-steam valve. It may also be reduced by varying the amount or period of the blast, or, conversely, the variation of the regular steam admitted. The percentage of gain resulting from the increased tempera- ture of feed-water in any particular case may be calculated by the formula Gain (per cent.) = 100(!T-0 H-t ' where H = total heat in steam at boiler pressure, reckoned from F. ; T= temperature of feed-water after heating; t = temperature of feed-water before heating. The quality of the steam supplied is quite important, the prop- erties being as follows : Saturated Steam. Saturated steam is steam in contact with and containing entrained water at the same temperature as the steam itself. The name may be also applied to the steam on the point of condensation, even when this steam is to all appear- ances perfectly "dry " (not containing water in mechanical sus- pension), as long as the pressure and temperature remain un- 12 AMERICAN GAS-ENGINEERING PRACTICE. changed; but the slightest change in either of these two con- ditions will cause condensation on the part of a portion of the steam. Therefore, should a given volume of saturated steam be made to occupy a smaller space, the temperature remaining un- changed, the pressure will also remain unchanged, as enough of the steam will be condensed in the water to equalize the reduc- tion of volume by the change of space occupied. Saturated steam is therefore not a permanent gas, inasmuch as it cannot be compressed under a constant temperature without a change resulting to its physical nature. Superheated Steam. A good definition of superheated steam is as follows: " Steam which for the same pressure has a greater temperature, and for any particular weight a greater volume, than saturated steam at the same pressure." It is produced by the vaporizing or gasifying of the water out of the steam molecule of saturated steam. Therefore^, if its pressure is kept constant it tends to expand as its temperature increases. In some respects it is thus similar to a permanent gas; that is, if compressed under constant temperature, the pressure will at first increase inversely as the volume. This is, however, within limits; for, as the compression continues, the steam finally reaches the point of saturation, and thereafter the pressure cannot be increased by fur- ther compression under a constant temperature. The chief difficulty in the generation of superheated steam is to secure material for the superheater which will withstand the intense heat of the burning gases on the one side and the steam on the other. This difficulty has made its general use hitherto impracticable. Generally speaking, horizontal boilers produce steam strongly saturated, while vertical boilers have a tendency towards superheating. Quality of Steam. The quality of steam depends upon the quantity of heat it contains. It is wet if it contains fog or drops of water, dry if it contains just enough heat to keep it so, and super- heated when it contains more heat than FIG. 1. -Steam Sampling- nece to do go Thus if a gam le of K 1 M^? I'll 11 steam is obtained and condensed, measur- ing the heat given up and the water produced, the B.t.u. per pound of water can readily be calculated. The process by which this test is made is called steam calorimetry and the apparatus is a calorimeter. The throttling calorimeters are more accurate for steam containing very little moisture and superheated steam, but the separating calorimeter is best for general purposes. To obtain a sample of steam the steam-pipe is tapped and a sampling-pipe THE GENERATOR. 13 with a long thread screwed in until the end reaches the center of the steam-pipe. In the condensing types the weight of the ap- paratus and its specific heat must be known. This is obtained by adding a known weight of heated water, noting the rise in tem- perature, and what it should have been if the temperature of the water alone were considered. The difference divided by the final temperature and multiplied by the weight of the water will give the water equivalent of the calorimeter vessel which must be added to that of the water in the vessel. Barrel Calorimeter. This consists of a platform scales on which is a barrel into which dips a steam-pipe perforated near the bottom. The barrel should be large enough to hold 450 Ibs. of water, although only about 360 Ibs. are put into it. First let steam enter until the temperature of the water is about 130 F. to warm the barrel; empty it and add exactly 360 Ibs. of water, taking its temperature im- mediately, removing the steam- pipe and hose and warming it up with steam; insert again into the water and note the temperature of the water until it is about 110 F., when the steam must be turned off and the weight noted as well as the temperature. The increased weight will be due to the weight of steam condensed, and the increased temperature to the heat held by the steam. The quality of the steam is then found by the following formula: FIG. 2. Barrel Calorimeter. where Q = proportion by weight of pure dry steam in the sample; d weight of dry steam in the sample condensed; W= weight of condensing water in barrel, 360 Ibs.; w= weight of steam and water from steam-pipe; t = temperature of the steam at the gage pressure noted, to be found in steam tables; ti = initial temperature of condensing water; i 2 = final temperature of water after steam is condensed; 1 = total latent heat of steam at pressure of test to be found in steam tables; k = water equivalent of calorimeter, 14 AMERICAN GAS-ENGINEERING PRACTICE. Barrus Throttling Calorimeter. The following descrip- tion of a form of throttling calorimeter designed by Geo. H. Barrus of Boston will be found in Babcock & Wile ox Co.'s publication "Steam": FIG. 3. General Arrangement of Barrus Throttling Calorimeter. FIG. 4. Detail of Barrus Throttling Calorimeter. ** Steam is taken from a ^-in. pipe provided with a valve and passes through two f-in. tees situated on opposite sides of a f-in. flange union. A thermometer cup or well is screwed into each of these tees, and a piece of sheet-iron perforated with a |-in. hole in the center is inserted between the flanges and made tight with rubber or asbestos gaskets, which also act as non-conductors of heat. For convenience a union is placed near the valve as shown, and the exhaust steam may be led away by a short IJ-in. pipe, THE GENERATOR. 15 shown in the illustration by dotted lines. The thermometer wells are filled with mercury or heavy cylinder-oil, and the whole instru- ment from the steam-main to the H-in. pipe is well covered with hair felt. " Great care must be taken that the J-in. orifice does not become choked with dirt, and that no leaks occur, especially at the sheet- iron disc, also that the exhaust-pipe does not produce any back pressure below the flange. Place a thermometer in each cup, and, opening the ^-in. valve wide, let steam flow through the instru- ment for 10 or 15 minutes; then take frequent readings on the two thermometers and the boiler gauge, say at intervals of one minute. " The throttling calorimeter depends on the principle that dry steam when expanded from a higher or lower pressure without doing external work becomes superheated, the amount of super- heat depending on the two pressures. " If, however, some moisture be present in the steam, this must necessarily be first evaporated and the superheating will be proportionately less. The limit of the instrument is reached when the moisture present is sufficient to prevent any superheating. " Assuming that there is no back pressure in the exhaust, and that there is no loss of heat in passing through the instrument, the total heat in the mixture of steam and moisture before throt- tling, and in the superheated steam after throttling, will be the same and will be expressed by the equation ff-^r= 1146.6 + 0.480-212), in which x= percentage of moisture; H= total heat above 32 in the steam at boiler pressure; L = latent heat in the ste.am at boiler- pressure; 1146. 6 = total heat in the steam at atmospheric pressure; t = temperature shown by lower thermometer of calorimeter; 212 = temperature of dry steam at atmospheric pressure. " Calibration. Theoretically the boiler pressure is indicated by the temperature of the upper thermometer, but owing to radia- tion, etc., it is usually too low, and it is better to use the readings of the boiler gauge, if correct, or, better still, to have a test-gauge connected on the J-in. pipe supplying the calorimeter. " If the instrument be well covered, and there is as little radiat ing surface as possible, -the above assumption that there is no loss of heat in passing through the instrument may be nearly, though never quite, correct. On the other hand it is possible to be 16 AMERICAN GAS-ENGINEERING PRACTICE. very far from correct, and ; to eliminate any errors of this kind, Mr. Barrus recommends a so-called ' calibration ' for dry steam. This, again, involves an assumption which is open to some doubt, which is that steam, when in a quiescent state, drops all its mois- ture and becomes dry. No other practical method, however, has been proposed, and this is therefore the only method used at the present time. Some engineers, however, refuse to make any calibration, but instead make an assumed allowance for error. " To make the calibration close the boiler stop-valve, which must be on the steam-pipe beyond the calorimeter connection; keep the steam pressure exactly the same as the average pressure during the test for at least fifteen minutes, taking readings from the two thermometers during the last five minutes. The upper thermometer should read precisely the same as during the test, and the lower thermometer should show a higher temperature; this reading of the lower thermometer is the calibration reading for dry steam, which we will call T. " Calculation of results, allowing for radiation, by calibration method is made by this formula: in which x= percentage of moisture; T= calibration reading of lower thermometer; Z = test reading of lower thermometer; L = latent heat of steam at boiler pressure. " The method of taking a sample of steam from the main is of the greatest importance, and more erroneous results are due to improper connections than to any other cause. The sample should be taken from the main steam current of the steam ascend- ing in a vertical pipe. Avoid perforated and slotted nipples and use only a plain, open-end nipple projecting far enough into the steam-pipe to avoid collecting any condensation that may be on the sides of the pipe. Take care that no pockets exist in the steam- main near the calorimeter in which condensation can collect and run down into the sampling-nipple. Make connections as short as possible. " As mentioned above, there is a limit in the range of the throttling calorimeter which varies from 2.88% at 50 Ibs. pres- sure to 7.17% at 250 Ibs. When this limit is reached a small sepa- rator may be interposed between the steam-main and the cal- orimeter, which will take out the excesses of moisture. By weigh- ing the drip from the separator and ascertaining its percentage of the steam flowing through, and adding this to the percentage of moisture in the steam, the total moisture may be ascertained. THE GENERATOR. 17 It is seldom, however, in a well-designed boiler that any but a throttling calorimeter becomes necessary." Generator Details. It is not necessary to determine the specific gravity of steam coal as a method of checking the uni- formity of the supply. The difficulty of securing a fair sample of the run, and the inaccuracies incident to the determination, have made this method of but little value, it being entirely inadequate as compared wifch the more general custom of a complete analysis. An even more practicable method than such analysis, perhaps, is that of keeping an exact and careful account of results obtained. As a substitute for the usual steam-nozzle under the grates of the generator, an ordinary malleable T fitting may be used, the steam-connection being in the side of the fitting. This has the advantage of acting in a small way as a steam-separator, the incoming steam impinging against the side of the T and the con- densation or drip falling through the lower opening. The general results of the modern water-gas generator (U.G.I, apparatus) indicate a consumption of from 30 to 32 Ibs. of water per 1000 cu. ft. of gas made. Of this steam only about 50% is actually converted into gas, or, in other words, only about 15 to 16 pounds of steam per thousand feet of gas is dissociated, entail- ing a loss in net efficiency of from 2 to 3 Ibs. of boiler fuel, to say nothing of the generator fuel wasted and " killed." The propor- tion of steam decomposed, says Mr. Norris, during the early part of the run, is much larger than during the last few minutes, and this seems to point towards desirability of shorter runs, and pos- sibly a more closely regulated admission of steam, instead of fol- lowing the usual custom of admitting steam at a constant rate throughout the entire run. In addition to this, as has been before mentioned, the make of CO 2 is in inverse ratio to the steam dis- sociated. The matter of short runs may be carried to an extreme, making the regulation of generator heat difficult and reducing the gross production of the machine per hour materially. The quan- tity of steam used in the engine operating the blower of a water- gas set is variously estimated at from 15 to 30 Ibs. per 1000 cu. ft. per hour. The amount of water necessary for boiler evaporation, steam for exhausters, fan-engines, oil-pumps, etc., will average about 5 to 6 Ibs. per 1000 cu. ft. of gas manufactured. The average amount of boiler fuel necessary to convert this water into steam will average, perhaps, 1.5 Ibs. of coal per boiler per horse-power hour. The boiler installations in a water-gas plant should never exceed the minimum of 2.5 h.p. per 1000 cu. ft. of make per hour, 3 h.p. being a safer factor for installation. In small works there should always be in reserve one boiler; in large works the proportion- 18 AMERICAN GAS-ENGINEERING PRACTICE. ate reserve of one boiler in five should be maintained. A. S. Miller says that the consumption of steam in his experiments equalled 67.34 Ibs. per 1000 cu. ft. of gas manufactured. This will not allow for steam used in heating. In steam-piping for engines, where bends are used the fitting at joints should be done with a slight stress upon the cold pipe. No actual rule for this can be stated except as determined prac- tically by any expert fitter. When the pipe becomes hot this strain is removed by expansion and leaves it more ready to receive the vibration to which it is subjected. Good fitting with the best material obtainable is invariably economy in the end. Steel flanges welded to the pipe and pulled up with intervening copper gaskets make the tightest joint. Where high-pressure steam is used and the work can be accomplished without a drop of pressure of, -say, 4%, it is good practice to run from the boiler (if near at hand) a steam-pipe of one or two sizes smaller than the inlet or throttle valve of the engine. This pipe should be increased to full size within a few feet of the throttle, which serves the dual purpose of having the full supply of steam close at hand, to meet the admis- sion stroke and also to cushion the kick or recoil of the steam due to the closing of the valve at the point of cut-off. Generator Operation. A sight-cock is of unquestionable advantage when placed on the coaling-valve of the generator, in that it may enable the gas-maker to watch the condition of his fire without opening the valve. Many superintendents use this sight-cock as a test for " excess steam " on the generator, such being denoted by moisture on the inside of the eye-glass during the run. In letting down or putting out of operation a set, the best practice dictates that the generator lid, or coaling-valve, be left closed. The clinkering-doors are, however, left slightly ajar, a slight draught should be left on the carburetter through the blast- valve (the blower being shut down), and the top sight-cock on the carburetter left open, as is also, of course, the stack-valve. on the superheater. It is a common practice on machines with reversing steam connections to make every third run a down-run, except that one preceding and the one succeeding the coaling period, when the down-run should always be omitted. Generators should be clinkered and thoroughly cleaned at least twice every 24 hours. In this operation the machine should be let down, the coaling-valve or lid opened, the clinkering and ash doors also being opened or removed ; the fire should then be barred down thoroughly and all lumps of clinker and ash carefully removed. This clinker, if allowed to remain, is not only inert and wasteful THE GENERATOR. 19 of heating space, but it prevents the blast from proper circulation and has a remarkable condensing effect upon the steam. It tends to chill the fire and prevents diffusion of both air and steam through- out the generator area. For the elimination of carbon deposits on the checker brick of the carburetter and superheater, Mr. R. H. Sterling of Watson- ville, Cal., suggests the burning of zinc in the generator, a process which has served him most successfully. To reduce the cost of what would otherwise be a very expen- sive process, the zinc parts of old dry-cell batteries, spent elec- trodes, scrap zinc, etc., are used; such being obtainable from the telephone and telegraph companies, junk yards, tinners, etc., at a nominal cost. This zinc is thrown into the generators with the fuel and burned, having a tendency to remove the carbon deposits as aforesaid. The linings of a water-gas generator should, in the case of a good quality of material and an average grade of coke or anthracite coal, last at least three years; the period, however, is apt to be somewhat shorter with coke than coal, by reason of its rapid variation of temperature and intensity of heat; moreover, should either this coke or coal be high in ash or have a marked tendency to clinker, the life of the linings may be reduced to two years. The life of these linings is also materially affected by the care of handling, heats of " green sets " should of course be brought up slowly, sets should not be "forced," etc.; the necessity of careful operating conditions being intensified in the case of the checker brick, which under the use of average quality gas-oil should last "the rise" of a year, while other conditions of operation may reduce their service to half that period. It is the belief of the writer that the most disastrous element in the operation of either linings or checker are long daily " stand- bys," wherein the temperatures of the apparatus have time to greatly vary. This fact will also be observed in the case of coal- gas benches, which frequently vary in life from 5 years to 3 years, according to the nature of their service. Generator Fuels Compared. Anthracite coal contains less ash than gas-coke and will, therefore, make less clinker. Since it is much denser than coke, a given generator volume will hold a much greater weight of coal fuel and it will neither heat up nor lose its heat as rapidly as coke. Therefore when coal is used longer runs and blows or blasts should be made, as this increases the make or gas production of the machine per hour by the differ- ence in time required for the opening and closing of valves in put- ting on and taking off runs and blows on the apparatus; this time is materially increased in the use of coke by the fuel-charging 20 AMERICAN GAS-ENGINEERING PRACTICE. period, which occurs much more frequently in the use of coke than of coal. As an advantage, however, on the side of coke, it presents to the action of the blast and to the steam a much larger surface than does anthracite coal, owing to its porous nature. The irregular form and roughness of the surface of the individual pieces of coke keep the fuel-bed in a condition favorable to the general and inti- mate contact of both blast and steam with the carbon of the fuel. The heat can therefore be gotten up quickly, and the gas made at a rapid rate during the shorter run and, with quick workmen, the increase of time required for handling the valves, owing to the shortness of the blow and run, is not of great importance. It is necessary when using gas-coke to be very careful not to prolong either the blows or runs, for, owing to the rapidity with which the coke is consumed, any over-blowing largely increases the fuel account, while any extra length of run increases the amount of carbonic acid in the gas very rapidly, since the fire cools off quickly. It has been the experience of the writer that coke is most advan- tageous when used in sets too small to have reverse steam connec- tions, as the coke revivifies more rapidly and presents a larger and fresher surface to the action of the steam. It is also less apt to form into pits and blast-holes, through which the steam in the generator may pass undecomposed. In general it is probable that fair results as to the quantity of fuel per 1000 cu. ft. of gas manufactured and the quality of the gas made can be secured more readily from coal than from gas- coke, especially when large machines are used. Furnace- or oven-coke, unless it is made from carefully washed coal, or coal that is originally free from ash, is apt to contain more ash than gas-coke and to give trouble from clinker. It does not possess the density of anthracite coal, nor is it as porous as gas- coke. The 48-hour coke makes a much better generator fuel than the 72-hour hard coke. Opinions as to the relative values of these cokes, however, differ. There is much more to do with the proper handling of these fuels than with the little differences which exist between them, for even slight differences in the price or local con- ditions are sufficient to turn the advantage in favor of one or the other. When anthracite coal is used, the trustees of the Educational Class of the American Gaslight Association suggest as follows: " The size of anthracite that is usually considered available for generator fuel is either ' steamboat/ consisting of pieces that will pass through a screen with 4- to 7-in. mesh (the smaller pieces having been screened out) ; or ' broken/ consisting of pieces that would pass through a 4-in.-square mesh and over a 2f-in. mesh; THE GENERATOR. 21 or ' egg/ consisting of pieces that would pass through a 2J- to 2f- in. mesh and over a IJ-in. mesh. Of these sizes that known as ' broken ' has been found to give the best results for generator use, though in many large generators (those over 8 ft. in diameter) steam- boat size would be better. The advantages possessed by ' broken ' coal are that the lumps are sufficiently large to maintain the bulk of the fire in an open state, which affords the ready passage to the air in blasting and the steam when making gas, and yet are small enough to present a large surface of carbon to be acted upon by the oxygen, and it is thus possible to secure the proper combina- tion of the greater portion of both oxygen and carbon in each case. Smaller coal affords a larger coal surface, but at the same time forms a large compact mass in the center of the generator through which the air and steam cannot pass readily. They therefore pass only through that portion of the area of the generator which lies between the outside walls and this compact mass in the center. The larger-sized coal affords a freer fire with much less total sur- face, and is also much harder to handle. " In his paper on the subject, C. R. Collins states that the inac- tive portion of the fire which is due to the compacting of the coal in the center of the generator, where the lumps can fit each other more perfectly than they can in the space next to the walls, " varies with the diameter (of the generator) and with the size of the coal; thus in a particular generator ' egg ' coal renders about 30% of the fire partially inactive, the bulk of the work being done in the outer parts representing 70% of the fuel ; in the same way ' broken ' coal affects about 15% of the fuel-bed, while ' steamboat ' coal leaves a practically free fire. . . . ' Steamboat ' coal presents ap- proximately 7 sq. ft. of surface for each cubic foot of generator space. ' Broken ' coal, 10 sq. ft. of surface per cubic foot of space; and ' egg ' coal, 22 sq. ft. of surface per cubic foot of space. These figures are for selected coal of the standard size in each case. In practice the ' steamboat ' coal will have some broken coal in it, and the ' broken ' some ' egg/ and so on, and the presence of this smaller coal will increase the size of the inactive portion of the fire as well as the amount of average surface presented to the steam. It is important, no matter what size is being used, that the smaller pieces and slack should be screened out and not used in the generator, the coal used being kept as nearly as possible to the size of the selected standard." What has been said with regard to anthracite coal also applies to coke. When oven coke is used the large pieces in which it comes from the oven should be broken up to a size corresponding to " broken " coal (i,e., pieces which pass through a 4-in. mesh and over a 2j-in. mesh), before the coke is charged into the generator. 22 AMERICAN GAS-ENGINEERING PRACTICE. On the other hand the coke after being broken should be picked up with a fork in such a way as to leave behind the small pieces and dust, which should not be used in the generator. When coke is made in coal-gas retorts it does not require any breaking, but must be picked up with a fork to avoid any presence of dust and " breeze." It must be remembered that a fork can be used in such a way as to pick up almost as much as a shovel, and that when loading coke which is to be taken to the generator the fork is to be well shaken while the coke is on it, for the purpose of dislodging the dust and small pieces that the larger pieces may have picked up. It is the author's opinion that the greatest field in the future economical production of water-gas lies along the development of superheated steam. As yet little seems to be known of this subject, the properties of the steam, its line of expansion, or its temperatures. But when these properties are thoroughly understood and adapted to water- gas manufacture, it is certain that the result will not only reduce the cost of manufacture by reason of the saving of generator fuel effected, but it will likely result in the manufacture of a more permanent and better gas, free from aqueous vapor or excess con- densation, together with the faults invariably attendant upon these features. Spontaneous combustion in coal seems to be favored by any or all of four conditions: first, the piling of the coal to any great depth (say 12 feet or more), so that the weight of the coal brings considerable pressure to bear upon the lower parts of the pile (same condition holds good with tight bins); second, finely broken or run-of-the-mine coal; third, a high percentage of sul- phur or iron pyrites; and fourth, moist and freshly mined coal are especially susceptible. Carbon Dioxide. This gas is due to incomplete reduction of the CO 2 first formed to CO by the upper layers of incandescent carbon, or to that remaining in the apparatus after blasting. As the temperature of the fuel falls the proportion increases, as shown in the following table: CARBON DIOXIDE IN WATER-GAS DURING A FIVE-MINUTE RUN. Minutes. End of 1 Butterfield. Per Cent. 0.3 O'Connor. Per Cent. 0.5 2 0.6 1.5 3 1.4 4.1 4 2.6 6 2 5.. . 4.2 7.9 THE GENERATOR. 23 The proportion of CO 2 is seen to increase with the length run. CO 2 in water-gas varies under normal conditions from 1 to .5 per cent, but only 3 per cent should be permitted in good practice. O'Connor's analysis of American water-gas is as follows: Constituents. Per Cent. CO 2 3.5 CO 43.4 H 51.8 N 1.3 Water-gas of itself has practically no illuminating power, having a faint bluish color. ^ When air is forced through red-hot coke, 1 Ib. of carbon, burn- ing to CO, liberates 4500 B.t.u.; but if burned to CO 2 it liberates 14,500 B.t.u. If there be sufficient quantity of carbon for the CO 2 to pass through, it is decomposed with the absorption of 10,000 B.t.u. Since 1 Ib. of C requires 1.25 Ibs. of O to form CO, it produces 2.25 Ibs. of CO. The quantity of air containing 1.25 Ibs. of O would contain 4.5 Ibs. of N. The minimum temperature for the formation of pure water-gas is 1800 F. A lesser heat would mean imperfect combination of the C and O and result in the production of CO 2 . Too little attention is generally given to the maintenance of uniform heats in the generator and to the keeping down of the per- centage of CO 2 . Some idea as to the detrimental effect of this compound will be given by the following approximate table: EFFECT OF CARBON DIOXIDE ON THE CANDLE POWER OF GAS. 2.5% CO 2 causes a loss of 9% in candle power. 5% i t 1 1 n i ( " 20% " i t tt 10% tt ft a ( t " 40% " tt tt 20% tt it it tt " 75%" 11 tl 30% tt 1 1 " tt " 90%" It tt 58% 1 1 1 1 " 1 1 " 100%" tt tt Carbon Dioxide Analysis: Description. "As the amount of carbonic acid in the water-gas depends largely on whether the apparatus is properly handled or not, and as an excess of carbonic acid very seriously affects the illuminating power of the gas, it is convenient to have an apparatus by which the percentage of car- bonic acid can be quickly and easily ascertained at any tune. The fact that carbonic acid is readily absorbed by caustic potash is taken advantage of as follows: A solution of about 1 part by 24 AMERICAN GAS-ENGINEERING PRACTICE. weight of potash to 3 parts by weight of water is prepared. The absorption and measuring apparatus shown in Fig. 5 is placed in a convenient position and the absorption pipette is filled with the potash solution. This pipette is best filled when made with small rolls of iron-wire gauze, as the absorbing surface is thus much increased. One branch of the three-way cock at the top of the measuring burette is connected by the capillary glass tube with the pipette. The joints are made of rubber tubing. The measuring- burette is made to hold 100 cubic centimeters, and is graduated to read to 0.2 centimeter. A large glass tube, stopped at each end [FiG. 5. Carbonic-acid Gas Apparatus. with rubber plugs, is placed outside the burette. The space between the burette and the outside is filled with water, forming a water- jacket, which maintains the gas at an even temperature when in the burette*. A leveling-tube is connected by a long rubber tube with the bottom of the burette. This bulb is filled with water, preferably distilled, which has been saturated with gas by allowing a small stream of gas to bubble through it. Operation. " Open lower stop-cock 1 and turn three-way stop- cock (a) so that the burette is open to pipette; then, by lowering the level-bulb 6, draw the potash solution up the capillary tube to the point e, just before the capillary turns down, and close the stop- cock a. Leaving lower stop-cock open, turn stop-cock a until the THE GENERATOR. 25 capillary tube c is open to the burette, and then, by raising the level bulb 6, fill burette completely full of water. Close stop-cock 1. Now attach the rubber tube to the gas supply and allow gas to flow through the tube for a moment to displace air; then, with gas still flowing, attach free end of tube to capillary c. Open lower stop-cock 1, and then close stop-cock a and detach rubber tube. After 3 minutes bring the level of the liquid in the burette exactly to 100 c.c. merely by raising or lowering the level-bulb and close lower stop-cook 1. Open stop-cock a to capillary c for a moment hi order to allow surplus gas to escape. There will be exactly 100 c.c. of gas in the burette, measured under atmospheric pres- sure. Now open stop-cock a to the pipette and force gas over to the pipette by raising the level-bulb, draw gas back into the burette immediately, letting the potash solution follow up the capillary tube to the point e as before, and close stop-cock a. After 3 min- utes, by raising or lowering the level-bulb b, bring the water in burette and level-tube to the same level and close stop-cock 1. Note the point at which the water now stands in the burette, and the difference between this reading and the original amount taken will be the carbonic -acid gas absorbed. "The glass stop-cocks of the apparatus should be kept greased with glycerine, as otherwise they may stick and break when an attempt is made to turn them. A glass cock that has stuck can usually be loosened by the application of a cloth wet with hot water. In order to prevent the absorption of carbonic acid from the atmosphere, the open ends of both level-bulb and pipette should be plugged when the apparatus is not in use. Where unpurified gas is to be tested, the sulphureted hydrogen should be removed by passing the gas through a small oxide purifier before it is drawn into the burette. The solution of caustic potash in the pipette will last five or six months before it must be removed. This method of absorption is the base of all the usual forms of gas analysis, different chemicals being used to replace the caustic pot.ash and absorb the different components of the gas to be analyzed." Generator Lining. There should be a double lining in the generator, for that portion extending from just below the level of the grate-bars to a point, say, 5 ft. above these bars, which will be found most economical, for the reason that on this section is the greatest wear and tear, both from heat and clinkering, and this section can be renewed when necessary without disturbing the remainder of the lining. The rest of the lining may be made of single courses of blocks having the desired thickness, which is desirable, inasmuch as these courses require no support when the inner lining is renewed under- neath. Inasmuch as the wear of this last-named section is incon- 26 AMERICAN GAS-ENGINEERING PRACTICE. siderable, some saving in time and labor is effected by using the full-depth blocks. Rapid degeneration of generator linings usually indicates either excessive blast pressure, too lengthy blasts, or an insufficiency of blast. In the latter case the blast pressure is not sufficient in its velocity to carry the products of primary combustion over into the other retorts, where secondary combustion of the blast gases should take place. Hence both primary and secondary combustion take place in the generator alone. Repairing Cements. It is occasionally necessary to patch the fire-brick in the generator around the mouth or throughout the lining, and for this a compound of salt, sal-ammoniac, fire-clay, and finely powdered fire-brick is a good cement, as is also a composi- tion of iron filings 100 parts, fire-clay 50 parts, common salt 10 parts, and quartz sand or pounded fire-brick 20 parts. For attach- ing iron and stone or cement, a good composition is fine iron filings 10 parts, plaster of Paris 10 parts, sal-ammoniac ^ part. Fire- proof cement for iron pipes consists of wrought-iron filings 45 parts, fire-clay 20 parts, brick-clay 15 parts, common salt 8 parts. As a cement for filling in faults in iron castings: Iron filings free from rust 10 parts, sulphur J part, sal-ammoniac 0.8 part, mixed with water to a thick paste and rammed into the cavity. The part to be treated should be previously wiped with ammonia to free it from grease. The old cement commonly used for joining retorts to mouthpieces was | part by weight of fire-clay, J part by weight of iron borings, mixed with ammonia water. It is well to have on hand for emergencies a can of Tucker's cement. This cement is of especial use in making temporary patches on blast-pipes, gas-pipes, valves, etc., it being used to advantage when wrapped with strong muslin. It is peculiarly good in temporarily repairing reversing-valves between the generator and carburetter of the apparatus, which are invariably a subject for the " first aid to the injured," as they are but rarely sufficiently water-jacketed. Blast. Under date of December 21, 1903, D. J. Collins said with regard to the blast pressure to be maintained in the generator of water-gas sets: "With the use of anthracite coal as generator fuel you should maintain a blast pressure under the generator equal to a water volume of 15 in. to 18 in., and with coke from 12 in. to 15 in. The same pressure applies to all sizes of apparatus. The lower pressure with coke is made necessary because the coke is so much lighter and has so many more open spaces in it that the blast pressure should correspond with the conditions met." The blast on both generator and carburetter should be con- stant in its pressure, and the blast line should be thoroughly ven- THE GENERATOR. 27 tilated. This is necessary to prevent the accumulation of dust, oil, or gas in the blast line during the run, or in the pockets of the valves immediately connecting the machines, and which would occasion an explosion at the opening of the valves and starting up of the blast. This is especially needful in the instance of machines having reverse steam connections. Safety Devices. All en%)loyees about the works should be taught the location of all valves, steam, water, and fas, which should be labeled as to direction of rotation, and should be espe- cially drilled in the routine of their duty in case of fire. There should be near the generator and at convenient points about the works (especially in the purifying room) standard 2^-inch water- outlets, with suitable fire-hose attached and neatly coiled on racks ready for instant use. This hose should preferably be linen and unlined, inasmuch as lined hose, especially rubber, is damaged and of short life by reason of the heat about the works. One of the most frequent occasions for delay and shut-down in water-gas manufacture is due to explosion in the blast-pipe or of difficulties with the blower. It is strongly advisable to have inserted in each line of blast-pipe a T equal in diameter to the main line. On this T should be a cap fitted into the T and wrapped ,1-A \ - *T <#* r V V g AC/fi. -p ~nn h BLAST PIPES. FIG. 6. Safety Blow-off Blast-pipe. with some fabric such as tire-tape or electric insulating tape. This joint should be made to withstand a pressure of not more than one pound, or 27 inches of water, and is designed in case of an explo- sion to act as a safety-valve upon the blast line. Fire=brick. The principal precaution to be taken in laying fire-brick or fire-clay blocks is that the bricks or blocks should be thoroughly wet just before they are laid in place, and that each brick or block should be rubbed into place in such a way as to bring its faces in contact with the faces of adjacent brick or block in the wall, the joints being made as thin as possible, and at the 28 AMERICAN GAS-ENGINEERING PRACTICE. same time to have the fire-clay cement or mortar fill all the inter- stices, so as to give a uniform bearing over the whole surface. This is especially important in the case of arches, which should be laid as nearly as possible with the blocks face on face. Small bricks and blocks can be wet by being dipped in water. The surfaces of large blocks should be wet by having water poured on them with a hose. The portion of the work previously laid, and upon which the wet bricks or blocks are to be placed, should also be wet. To secure thinness of joints those surfaces of the blocks which come together should be smooth, plane surfaces, being dressed to this condition if they do not originally possess it, and the fire-clay mortar should be mixed thin rather than stiff, care being taken that it is not so liquid as to run out of the joint, nor so stiff that any excess will not be squeezed out when the joint is worked into place. If the joints are not made thin the fire-clay will soften and run when subjected to extreme heat, or it will shrink under the action of heat and cause the upper portion of the brickwork to settle. When it is necessary to cut bricks or blocks, the cut or broken section should never be exposed to the direct action of the fire, the face so exposed being always the one uncut or unbroken. The qualities desired in fire-bricks or blocks are infusibility, strength, regularity of shape, uniformity of composition and facil- ity of cutting, and the test to be applied to a fire-brick should be such as would determine to what extent it possesses these qualities. An excellent test for the fire-resisting qualities of fire-brick is to throw a brick into the generator along with the coal or coke and allow it to pass through, taking it out with the generator screenings. Any tendency to fuse or crumble will then be indi- cated by the condition of this sample. The degree of infusibility can be determined to a certain extent by an analysis of the material of which the brick is composed . If this analysis shows the presence of about 60% of silica, less than 6% of sequioxide of iron, and not more than 2% to 3% as the total of lime, magnesia, and hydrates of potassium and sodium, the brick probably possesses a high degree of infusibility. If the analysis indicates more than 6% of sesquioxide of iron, or more than 2% to 3% of lime, magnesia, etc., the brick should be rejected; but exposure of the bricks to the action of heat under the conditions to which it will be subjected when used, furnishes the best test of fusibility. In coal-gas works it can be made by placing the brick in the combustion chamber of the generative bench. If when the brick is removed, after being exposed for a week to the heat of the chamber, the edges and corners are found to be sharp and the sur- faces show no signs of incipient fusion, the brick may be passed THE GENERATOR. 29 as a ili'st-rate quality in respect to infusibility. In water-gas plants the space at the bottom of the superheater in which the secondary combustion occurs furnishes a good place for the test, or the pas- sage of a sample brick through the generator together with the fuel. If the material of which the brick is made is well compressed during manufacture, and the brick is hard-burned, there is little question as to its strength when cold; any defect in material or manufacture is indicated by crumbling or fusing. The degree to which compression has been carried is indicated by the weight of the brick. A fire-brick of regulation size, 9x4.5X2f inches, should weigh in the neighborhood of 7.25 to 7.5 Ibs. A well-burned brick should have a reddish tinge. A well-compressed and well-burned brick should give a ringing sound when struck with a hammer. It is especially necessary that bricks in the lining of retort-benches and water-gas generators should be hard, since they are subjected to a great deal of abrasions from the fuel and the clinkering-bar, so that to this work hardness and strength are really of as much importance as infusibility. In the combustion chamber, as in the carburetter and superheater, infusibility is the more important quality, since the material used is not exposed to any wear and tear except that arising from the effects of the heat, and it may thus frequently happen that the same brick is not suitable for use both in the furnace or combustion chamber and in the two other chambers. An examination of the exterior of the brick is all that is necessary to determine whether or not it possesses regularity of shape. Uniformity of composition can be ascertained by breaking the brick and examining the surfaces of the fracture. This should present a compact and uniform appearance, though not necessarily a close and fine texture. In fact some authorities prefer a coarse texture, as possessing greater infusibility. Uniformity of composi- tion is also indicated by the giving out of a clear ringing sound when the brick is struck a sharp blow with a hammer or trowel edge. Facility of cutting is important only as reducing the cost of labor and the amount of waste during the operation of laying the brick, and, while desirable if it can be secured without sacrificing the more important qualities, cannot be considered as equivalent to any of the other specified qualities. (The above information is credited to the trustees of the gas educational class of the American Gaslight Association.) It will be observed in the study of fire-clays (clays having a fusing-point above 2700) that the coarser-grained fire-brick stand heat better than the finer texture, although they stand less well 30 AMERICAN GAS-ENGINEERING PRACTICE. the action of molten metal. In their order they have been classed as: No. 1. Highly refractory: a. Flint fire-clay; 6. Plastic fire-clay. No. 2. Moderately refractory: a. No. 2 "A " fire-clay; b. Stoneware clay; c. Sewer-pipe clay. The method of manufacturing fire-brick, as well as the material of which they are made, has undoubtedly much to do with their degree of excellence. For example: All things being equal, the heat conductivity of the brick would vary in accordance with the pressure which was applied to it during its manufacture, the air spaces between its particles, or the porosity of the brick, decreas- ing its conductivity. The size of a water-gas generator is determined by most engi- neers by an allowance of one square foot of grate surface for each 30,000 cu. ft. of gas made in 24 hours; the fuel-bed to be at least 8 to 9 ft. deep. The data given by Alfred Wolff of New York City are very often used for computing the amount of heat passing through fire- brick walls. A gives the thickness of the wall in inches, and B gives the corresponding number of B passing through the walls per square foot of area per hour for each degree difference of tem- perature (Fahrenheit) between the two sides: A 44 8 12 16 18 20 24 28 32 36 40 B 0.43 0.37 0.32 0.28 0.26 0.25 0.24 0.22 0.21 0.18 0.18 Hornby says, under Analyses of Fire-brick and Clay, pp. 194 to 199: A refractory fire-clay will contain nearly pure hydrated silicate of alumina. The more alumina there is in proportion to the silica the more infusible will be the clay. The composition of different fire-clays necessarily varies, however; they contain: Silica 59 to 96 per cent. Alumina 2 to 36 " " Oxide of iron 2 to 5 " " and a very small percentage of lime, magnesia, potash, and soda. The fire-resisting properties of the clay depend chiefly upon the relative proportion of these constituents. If oxide of iron or alkalies are present in large proportion they act as a flux and result in fusion. The clay is then no longer refractory. THE GENERATOR. 31 Fire=clay Analysis. The following is the method of analysis: The quantity of the substance (either fire-clay or fire-brick) is reduced to an impalpable powder in an agate mortar and placed in a stoppered weighing-tube. About 2 grams of this sample are dried in a platinum crucible or dish at a temperature of about 100 C. (212 F.) until the weight is constant; the loss in weight gives the moisture. In the case of fire-clay it is then ignited, at first gently and then strongly and for a tolerably long time. The loss of weight corresponds to the water in combination together with the organic and volatile constituents of the clay, if such are present. Then 1.5 grams of the powdered sample are weighed accurately into a platinum crucible and about four times this weight added of a fusion mixture, consisting of sodium and potassium carbonates. The whole is intimately mixed by means of a smooth, rounded, glass rod. It will be found convenient to add the fusion mixture by small portions at a time, since in this way a more thorough mix- ture is obtained. The mixture should only half fill the crucible. The lid is then placed on the crucible and the latter gently heated over the Bunsen flame; the temperature is gradually in- creased, care being taken that no loss occurs through boiling over due to the evolution of CO 2 . When the mass is fused the crucible is transferred to the blowpipe flame, and the whole is kept at a bright red heat until bubbling ceases and the fused mass becomes tranquil. The flame is then removed and the crucible is allowed to cool just below redness, when it is placed on a cold surface, such as a clean block of iron, in order to assist it in cooling rapidly. When cold the crucible and its contents are placed in a deep evap- orating dish or in a shallow beaker; this is covered with a large watch-glass and tolerably strong hydrochloric acid added to the contents, which should be gently agitated after each addition of the acid and kept covered during the operation. When efferves- cence has ceased and the crucible is free from all adherent solid, remove the crucible by means of the crucible tongs, carefully rins- ing off any adhering liquid, by means of the jet from the wash- bottle, into the main portion of the liquid. On treating the fused mass with HC1, as above described, most of the SiO 2 will separate out as a gelatinous mass. If any gritty particles are felt, on stirring the bottom of the vessel with a glass rod, the fusion is imperfect. This is generally due to the original substance not having been powdered sufficiently finely. In this event it is usually more satisfactory to make a fresh fusion, taking care that no coarse particles are present in the portion of the sample used for the new fusion. a. Estimation of the Silica. The liquid containing the gelat- 32 AMERICAN GAS-ENGINEERING PRACTICE. inous silica is now transferred (if necessary) to an evaporating basin, preferably of platinum and evaporated to dryness upon a water-bath. When the contents of the basin become pasty they should be continually stirred with a rounded glass rod to prevent the formation of lumps. When all the liquid has been driven off, the contents of the dish should then be in the state of fine powder. In order to expel the last trace of HC1 the dish should now be placed upon a sand-bath and heated with a small Bunsen flame until no moisture is deposited on a cold clock-glass when placed upon the dish for a few seconds. The dish is then allowed to cool and its contents are moistened with strong HC1. It is then heated on a water-bath for about half an hour, a small quantity of hydrochloric acid being occasionally added with stirring. Hot distilled water is now added and the silica is filtered off and is washed free from dissolved chlorides. The precipitate is ignited apart from the filter, the precipitate being transferred to the platinum crucible cau- tiously, since it consists of a very light powder which is easily blown away. The lid is placed on the crucible and the latter heated, exceedingly gently at first and the temperature raised very gradu- ally, or the escaping steam will carry some of the fine powder away with it. The crucible is finally raised to a full red heat over the Bunsen flame and the silica weighed. b. Estimation of Al ?i O^ and Fe 2 3 . The filtrate from the SiO2 determination is mixed with . NH4C1 solution and then with NH 4 OH in slight excess, the hydrates of iron and aluminium depositing as a precipitate. This precipitate is washed, and dis- solved upon the filter in hot diluted hydrochloric acid, and the solution allowed to flow into a nickel or porcelain dish contain- ing about 50 c.c. of pure strong KOH solution. Wash out the acid which remains in the filter-paper with a small quantity of distilled water, allow these washings to also run into the dish and boil the contents of the latter for a few minutes. The iron will be precipitated as ferric hydrate, while the hydrate of alu- minium will remain in solution. The iron precipitate is filtered out, again dissolved in HC1 and reprecipitated by NH 4 OH in order to free the ferric hydrate from KOH. It is then filtered, washed, ignited apart from the filter at a red heat and weighed as Fe 2 O 3 . The filtrate of alu- minium hydrate in the KOH solution is treated with a slight excess of strong HC1, and then with a very slight excess of NH 4 OH. The precipitate is then filtered off, washed, dried, ignited, and weighed as A1 2 O 3 . Another method of separation after weighing the mixed hydrates of iron and aluminium is to dissolve them in KHSO 4 and about 5 c.c. of H 2 SO4; add about 1 gram hyposulphite of soda, THE GENERATOR. 33 boil and titrate the solution with a 1 per cent solution of normal bichromate of potash; this will give the amount of iron. c. Estimation of Calcium. If the volume of the filtrate from the iron and alumina precipitate is very large, evaporate it down to a convenient bulk, add a little NEUOH if not already alka- line and then a slight excess of ammonium oxalate. Allow the liquid to stand and the precipitate to settle, filter off, ignite and weigh the precipitate as CaO. d. Estimation oj the Magnesium. Evaporate the filtrate and washings from the calcium oxalate precipitate to dryness, ignite the residue and treat it with a little strong HC1; add water and filter if necessary. To the clear solution add ammonium hydrate in moderate excess, and then an excess of sodium hydrogen phos- phate solution. Allow the liquid to stand for a few hours, or shake it vigorously in a stoppered bottle, filter off, wash the pre- cipitate with dilute ammonium hydrate solution, then ignite it and weigh the magnesium as Mg 2 P 2 O7. e. Estimation oj the Alkali Metals. Since sodium and potas- sium carbonates have been employed in the fusion, the alkali metals cannot be estimated in- the filtrate from the magnesium determination. A separate portion of the fire-clay sample is accordingly used for their determination. Lawrence Smith's method for the determination of the alkali metals will be found the most convenient. The following is the mode of procedure : Weigh out accurately about 1.5 grams of the finely powdered substance into a platinum crucible, intimately mix this with a mixture of 1.5 grams of pure recrystallized ammonium chloride and 9 grams of pure calcium carbonate. Then either heat the crucible to bright redness for an hour over a good Bunsen or blow- pipe flame, or preferably as follows: Place the platinum crucible in a clay crucible containing a little calcined magnesia or lime at the bottom and round the sides, and heat the clay crucible in a gas-furnace which is capable of maintaining it at a bright red heat. When the crucible has been heated for an hour, allow it to cool, place the platinum cru- cible and its contents in hot water hi a covered platinum or por- celain dish and boil for a time. This procedure will dissolve out the alkaline chlorides together with some calcium hydrate. Filter and mix the filtrate with NH 4 OH and (NH 4 ) 2 CO 3 solutions in excess and with a few drops of ammonium oxalate solution. Allow the liquid to stand, filter into a platinum or porcelain dish, evaporate the filtrate to dry- ness and heat the residue just below redness, but sufficiently strongly to drive off the ammoniacal compounds. 34 AMERICAN GAS-ENGINEERING PRACTICE. Dissolve the residue in water containing a few drops of NH4OH and ammonium oxalate solution to precipitate any trace of calcium compounds still in solution; filter, evaporate the filtrate, heating it to redness in a weighed dish after adding a few drops of HC1. Gently ignite the residue and weigh, repeat- ing the ignition until the weight is constant. The weight of the residue thus obtained gives the combined weight of the alkalies as KC1 and NaCl. The residue is then dissolved in water and the potassium chlo- ride is precipitated by platinic chloride in the following manner: To the solution of the residues a few drops of HC1 are added, then an excess of platinic chloride solution, the liquid being afterwards evaporated on the water-bath until a semi-solid crystalline mass is obtained. The platinic chloride is seen to be in excess by the supernatant liquid being of an orange color, after the liquid has been concentrated to a small bulk. When it is certain that there is an excess of platinic chloride; we may then proceed according to either of the following methods : 1. Pour alcohol upon the mass, gently shake the liquid round in the dish so as to mix the contents of the same well together, allow the precipitate to settle completely and pour off the liquid through a tarred filter. Repeat these operations twice and finally transfer the undissolved double salt to the filter with the assistance of a small wash-bottle filled with alcohol. Continue washing the precipitate upon the filter with alcohol until the washings are no longer colored. Dry the filter and its contents at 100 and weigh as 2KCl.PtCl 4 . 2. A rather quicker method of treating the precipitated double salt is to wash it with alcohol by decantation until the alcohol is no longer colored, the alcohol being decanted through an untarred filter-paper. Care must be taken that as little as pos- sible of the precipitate is poured off with the alcohol. The double salt, freed from the excess of PtCl, is now washed into a platinum crucible, dried at 100 C. and weighed. The filter, which will contain a little of the double salt; is then incinerated, and the ash is dropped into the crucible and weighed. By deducting from this weight the weight of the filter-ash, the approximate weight of platinum left by ignition is found; this is calculated into double salt and the weight is added to that of the double salt already found in the crucible. If the quantity of precipi- tate left on the filter is appreciable, the weight of KC1 left in the filter-ash, not being allowed for, will introduce an error. The filtei in this case should be ignited in a separate crucible, the KC1 washed out from the ash by hot water, and the dried residue THE GENERATOR. 35 weighed. The true weight of the platinum in the ash is thus ascertained and is made use of as mentioned above. The weight of the sodium chloride in the mixed chlorides of potassium and sodium is then ascertained by difference. The chlorides are finally calculated as K 2 O and Na 2 O. CHAPTER II. THE CARBURETTER. THE carburetter one may divide into two topics: 1. That pertaining to the brick, and 2. That to the oil, oil- pump and appurtenances. Brickwork. Of the first it is difficult to lay down any exact rule, as conditions, the class of oil, and the class of brick used greatly alter the situation. It is perhaps well to have a brick neither too hard nor too soft, one which will not vitrify, fuse, and become brittle under the intense heat, nor yet crumble from being too soft. The ideal brick is one in such a condition that it attains its final hardness only after being subjected to the car- buretter heat. Many methods are in vogue as to the laying of brick in the carburetter and the use of "soaps." These ideas, however, are largely a matter of personal preference, as is the practice of " coning " the brick, or bringing the brick up to the oil-spray in a pyramidal form. The main point, however, lies in close attention and proper treatment of the oil-spray, which should be examined at least every coaling period, if not oftener, and freed from any clogging material or other hindrance to its free action. This item of oper- ation cannot be too forcefully emphasized, as, next to the proper maintenance of an even heat, it presents the greatest opportunity for the gas-maker to economize material. The bricks of the carburetter should also be examined periodi- cally and replaced as soon as they become carbonized. The life of bricks depends very largely upon the proper handling of car- buretter heat, for improper manipulation of this heat on the part of the gas-maker very quickly clogs and carbonizes them. This is especially true in the case of low heat and the crowding of more oil on the machine than it is able to vaporize. These heats are a matter of much discussion and diversity of opinion on the part of gas-makers, the author's best results being obtained by a condition of heat which shows a bright orange just short 36 THE CARBURETTER. 37 of a white tinge at the completion of a blast and a cherry-red at the completion of the run. The run should never be so long nor the quantity of oil turned in sufficient to "kill " the heat of the carburetter and to require relighting at the commencement of the blast. Regarding the cleaning of checker brick the committee of the American Gaslight Association states as follows: "The checker bricks of a water-gas apparatus should be re- moved and cleaned, or renewed, when dirty, crushed, or disinte- grated. Checker bricks may become covered with a non-conducting coating of ashes or carbon, or both, making impossible the desired exposure of the oil-vapors to properly heat the brick surfaces. When bricks are coated or saturated with carbon the surface heats rapidly, because the carbon burns, and the gas-maker is deceived by the glowing carbon and believes the bricks to be hotter than they are. It is possible to tell something of the condition of the checker bricks by observation through the sight-cocks provided for the purpose. Other indications of dirty bricks are a falling off in the rate of make per minute and in the oil results. If all the con- ditions of operating remain unchanged, and the candle power falls materially and stays down, and the make of gas per minute of run is reduced, the checker bricks should be at once examined and, if dirty, cleaned or renewed. Bricks should not be allowed to become so fouled as to make a material reduction in the rate of make. Experience soon teaches an intelligent gas-maker to avoid both the extreme of reduced results and of too frequent cleaning." Checker=brick Spacing. The carburetter and superheater shells are not only lined with fire-brick, but are filled with courses of brick with spaces between, so that during the blast these bricks may be heated to the degree required to fix the oil-vapor passing through them during run or gas-making period. The proper spacing of these bricks was the subject of an article published in Progressive Age (Oct. 1, 1904, p. 514) by J. A. Perry, in which the relation between size of brick and space between bricks to obtain the best results with both oil and fuel was developed into a formula, as follows, for size of brick 2.5x4.5X9 in.: 9 \(2z+5)V where F flame surface of checker brick in vessel after deducting surfaces in contact, in square inches; d = internal diameter of fire-brick linings of vessels, in inches; h = height from bottom to top of checker brick, in inches; x = space between rows in each course of checker brick. OF TH UNIVERSITY OF C>/ HFOR1 38 AMERICAN GAS-ENGINEERING PRACTICE. The accompanying curve shows the relation of F to x. Suppose Q cubic inches of gas pass through the total space between bricks in small interval of time t and # = - , M is a 18 i" r A- 2' 2V 3- a- 4' FIG. 7. Relation of Flame Surface to Spacing. variable coefficient depending on the temperature and specific heat of gases and brick, and H is the B.t.u. of heat absorbed by the checker brick during the blast in time t, then Q The first differential coefficient of H with respect to x, when placed equal to zero and solved, will give a minimum value for H. Let Y= (2z+5) 3 then the value of the first differential which will make it zero is 3.09 inches. The relation of Y to x is shown in Fig. 8. This figure shows that with a spacing of about 3.1 inches the absorption of heat by the checker brick is a maximum, although there is not much difference between 2.5- to 4-in. spacing evident on the curve. If we call b the time of blast in minutes, r the time of run in minutes, Vi the volume for gases between brick in one THE CARBURETTER. 39 case and 2 this volume for some other spacing, G\ the daily make for one spacing and G 2 the volume by another spacing, then From this it would seem that 3.1 inches was about the proper spacing for checker brick in the carburetter. The author claims i" r ii* 2' 2i* -3' Vi' f 4ii FIG. 8. Relation of Brick Spacing to Heat Absorption. for this spacing that it allows a quick blow with high blast, saving of fuel, better retention of heat by carburetter, improved oil yields, and increased output of gas. Close spacing keeps the temperature down, and wide spacing lets it rise. Thus for a 2.5-in. spacing Y is equal to 0.2875 and fora 1.25-in. spacing 0.2371, or a relatively lower heat absorption; the first might be employed in the car- buretter and the second in the superheater to keep the temperature down in the latter. However, with small spacing a hi^h blast is essential, and it is difficult to heat the carburetter sufficiently so that its brick should be relatively wide-spaced. Oil Supply. Another item concerning which opinion widely differs is the heat at which the oil should be turned into the car- buretter, many gas-engineers advocating the practice of vaporizing the oil prior to admission. The claims made for this method are: 1. The saving of fuel due to utilizing the waste heat of the machine during the blast in heating tue oil; 2. The saving to the checker brick of the carburetter; 3. The more perfect decomposition of the oil The efficacy depends somewhat upon the individual condition 40 AMERICAN GAS-ENGINEERING PRACTICE. and the character of oil used. In case the method of prior vaporiza- tion should be adopted, the easiest plan is to connect in to the pipe-line a return bend-coil (say a 1.5-in. pipe), to be situated in FIG. 9. Oil Preheater in Take-off Pipe. the take-off pipe of the superheater (Fig. 9). This coil may be made 10 or 12 ft. long (depending upon the size of the machine) and consist of some 6 or 8 coils, it being possible in this manner to THE CARBURETTER. 41 bring up the oil to a temperature of 700 or 800 F. prior to its admission into the machine. The whole principle is much the same as that of the feed-water heater and economizer in steam- boiler practice. There should be a relief -valve connected in series with this coil and emptying back into the measuring -tank. Be- tween the measuring-tank and the coil there should be a check- valve, as the pressure of the vaporized oil sometimes rises to several hundred pounds per square inch. FIG. 10. Oil-measuring Tank. Oil=pump. The oil-pump should be situated below the measur- ing-tank and before the oil-heater. It should maintain a constant pressure on the carburetter of from 60 to 70 Ibs. per sq. in. The piston-rods of this pump and the lining of the cylinders should be of brass to resist the action of the acid in the oil. The writer has found "Vulcabeston " packing especially applicable to oil-pumps. There is but one compound which has ever been successfully used in making tight oil-pipe joints, and it consists in equal parts of white lead, red lead, coach varnish, and dryers. 42 AMERICAN GAS-ENGINEERING PRACTICE. It will be noticed that the author has referred to a measuring- tank instead of an oil-meter, although either may be used. The tank (Fig. 10) is a simpler device, and may be used to advantage as a check even where the meter is used. The oil is pumped from the storage- tank to a small measuring -tank fitted with a glass gage having a scale calibrated to read in gallons direct. This tank is pumped full, and the connection with the storage-tank is then shut off. It flows by gravity and serves as a head upon the oil-pump, which then forces it into the carburetter. It is at all times accurate and requires none of the frequent adjustment attendant upon oil-meters. Oil Storage. It may be well in connection with the carburet- ter to note the oil-tanks and their convenient arrangement. When a tank-car is received at the company's siding it should be in- spected by the superintendent. A sample should be taken there- from and a hydrometer test made, after which a sample should be placed in a flask and allowed to stratify. As oil and water will form a mechanical mixture due to the churning of the car in motion, this mixture will separate and stratify if left undis- turbed for a sufficient length of time. Each works should be supplied with a copy of the Tank Gage Handbook, No. 2,* giving the capacity of every tank-car in use for hauling oil in the United States. It is well to have one tank of at least 10,000 gallons capacity, with a table showing its capacity at various depths of oil. This tank should be connected in series with any other stor- age-tank which it is most convenient to use, in solid units of 5000, 10,000, or 20,000 gallons each. An exceedingly flexible pipe system should be arranged by which each tank can be con- nected to the main line or any other tank. In this manner the storage-tank can be used in units, and the measuring-tank for fractional portions in the checking up of the contents of arriving cars. For example, we will assume the arrival of a car contain- ing 8000 gallons of oil. One tank with a capacity of 5000 gallons is connected to the tank-car and filled; the remain- ing 3000 gallons is then turned into the measuring-tank, thereby enabling the superintendent to exactly check the quantity of oil received. An oil-car is considered full when the oil level is flush with the top of the tank, where it is joined by the base of the dome. Inasmuch as oil-producing or -shipping companies occasionally bring up, in case a shortage is claimed, the question of tempera- ture, it is well to let down into the car of oil a thermometer and to record its temperature for future reference. * This book can be obtained by writing to the Central Traffic Association, The Rookery, Chicago. THE CARBURETTER. 43 As it is usual to have oil-tanks and unloadings occur on or near sidings, where there is a constant passing of locomotives and where there is danger that sparks may fall in and ignite the oil through the open dome of the tank-car, a hood should be pro- vided to screen such openings and at the same time permit the passage of air into the tank-car in order to prevent the tank from becoming air-bound. There is also, especially during hot weather, a vapor which arises from these oil-tanks, and it is well to put a connection be- tween storage-tanks and the holder in order that the holder pres- sure may be upon these vapors and at the same time permit the gas the benefit (if any) of the volatile hydrocarbons. Great care should be taken in examination of the spray or oil-injector of the carburetter. This, as has been suggested, should occur at frequent periods to see that it is in proper work- ing order and that the oil is being equally distributed over the entire surface of the carburetter brick. Rotary sprays have a tendency to clog and become jammed, thereby concentrating the oil upon a limited area of the brick, where it fails to evap- orate, is carried off as tar, and fouls the brick, while the unsprayed portions of the carburetter become unduly hot by failure of the cooling influence of the oil; this burns up both oil and brick, or forms naphthalene in such of the hydrocarbon vapors as even- tually escape. In addition to the test-lights used on all water-gas sets, it is well to have one or even two Knott jet photometers connected in series so as to check each other on the inlet of the storage- holder. This photometer should be checked by comparison with the regular bar-photometer at intervals of not more than a week. Grades of Oil. Of the gas-oils used for enriching water-gas, the three most common forms are crude oil, known as BS or petro- leum, naphtha, and gas-oil. Petroleum is the oil in its crude or native form as it comes from the well. It is a mixture of hydro- carbons, has different chemical compositions, varies in specific gravity and boiling-point, and can be broken up into these vari- ous substances by fractional distillation. The chief producing fields for crude oil are the United States, Russia, and Peru. Penn- sylvania and Ohio crude varies in specific gravity from 0.80 to 0.85 (water being 1). Its color also varies, the most common being a dark claret color by direct, and a greenish color by reflected, light. Oil commences to distil at 40 C. Some of the qualities of oil which make it suitable for gas-making are as fol- lows: It should be as nearly as possible free from water; the residue, after distillation, should not exceed 1 per cent.; only the last fraction should be of a pronounced dark color; the rapid 44 AMERICAN GAS-ENGINEERING PRACTICE. blackening of lead-acetate-impregnated paper should not take place until far along in the distillation; under ordinary circum- stances the first distillate should be nearly colorless, later becom- ing an amber or pale straw tint, only the last fraction indicating a decided brown. The flashing-point for this class of oil is usu- ally between 120 and 250 F. Naphtha is a general term given to those distillates of oil which are given off during fractional distillations of crude oil, between gasoline and lamp-oil; this oil is volatile and very in- flammable, its gravity running from 0.67 to 0.74. What is commercially known as "gas-oil" is a general name given to those distillates between the lamp-oil and lubricating- oil series; this oil has so high a boiling-point and is so heavy as to be useless for illuminating purposes, while it is not sufficiently viscous to be used as a lubricant. As a matter of fact, however, this term covers a multitude of odd distillates, or " waste oil " unfit for other purposes, and as a result, so-called gas-oil varies in color, gravity, and constituents, its average gravity being, perhaps, about 0.85. By reason of these variations in gravity, boiling-point, etc., it requires most careful handling on the part of the gas-maker, and he must constantly vary his heat in compliance with the strata of oil which he is taking from the tank, the manipulation of which requires much judgment and long experience. Chas. F. Cattell mentions the economical use of 20 per cent, of water-gas tar, with 80 per cent, of oil as a water-gas enricher, the apparatus in use being a six-foot Lowe machine, ordinarily using 20 gallons of oil and a make of from 4300 to 4800 cubic feet of gas per run. Separate tanks and sprays were used for injecting the tar, the tar being admitted to the generator. Oil Analyses. Concerning the method of examination for gas-making oils, the following is extracted from Butterfield's excellent treatise on Gas Manufacture: "The laboratory examination of an oil to determine its fit- ness for gas-making embodies the operations described here- under. The specific gravity of the oil and its temperature at the time of taking the specific gravity are ascertained. A hydrom- eter with an open scale serves for taking the specific gravity if the instrument is known to be correctly calibrated. The scale should be sufficiently open to allow reading accurately to within 0.0005; the thermometer should be in the oil while the reading is being made and be read immediately after the hydrometer. Failing the use of an accurate hydrometer, the specific gravity must be taken in the ordinary way with a specific-gravity bottle, but the high coefficient of expansion of petroleum renders care-? THE CARBURETTER. 45 ful and rapid working necessary, and care is requisite to obtain correctly the temperature of the oil at the time of weighing. By either method it is desirable that the specific gravity should be taken at the standard temperature, usually 60 F. ; but as this is generally impossible, it should be corrected to that tempera- ture by means of the coefficient of expansion of the oil, which may, in general, be taken at 0.00036 per degree Fahrenheit as an average value for petroleum oils. Oil is frequently bought and sold by v/eight, which is calculated from its volume and specific gravity, hence the accurate determination of the latter has special importance in many cases. "The flashing-point of burning oil is determined in England by the apparatus devised by Sir Frederick Abel and adopted as the standard by the Board of Trade. For oils of low flash- ing-point it is equal or superior to any of the forms of apparatus adopted in other countries. A description of the method of making a determination with it is given with each apparatus, and there will be little divergence in the results obtained by differ- ent operators if the directions are implicitly followed. Most oils suitable for retorting have, however, fairly high flashing-points, and the determination can be made with sufficient accuracy hi a much simpler apparatus. This consists simply of a cylindrical copper vessel, about 3 inches in diameter and 3 inches deep. The lid overlaps the top of the cylinder, but a flange inch deep attached to it fits within the cylinder and keeps the lid in posi- tion. The lid is perforated in two places: one hole is for the insertion of the thermometer held by a perforated cork fitting the orifice ; the other is covered by a small lid pivoted to the cylinder cover, so that the opening can be exposed by sliding the lid from it, and can be covered again immediately after each application of the test flame. The oil to be tested fills the cylinder to a height of 2 inches, and the bulb of the thermometer is immersed in the liquid when the cover is in position. Heat is applied to the bot- tom of the cylinder by means of an Argand burner and a sand- bath, so that the temperature of the oil rises about 1 F. per minute. As each degree of the thermometer scale is reached the opening in the cover is exposed and a small gas flame passed over it. If no flash is observed, the opening is closed until the next trial is made. The temperature at which the flash is first observed is noted, and recorded as the flashing-point of the oil. If it is wished to confirm the result a fresh portion of the oil must be taken for a second determination, as oil that has once flashed will not again flash at its original flashing-point. The gas flame used for testing should be J to inch in length, and is readily obtained by fusing the end of a piece of hard glass tube until AMERICAN GAS-ENGINEERING PRACTICE. the orifice allows only sufficient gas to pass through at its or- dinary full pressure to give that length of flame. For accurate determinations heating the cylinder in an air-, water-, or oil-bath may replace direct heating by an Argand burner. The apparatus should be protected from air-currents during the de- termination. It is illustrated in Fig. 11. A more elaborate apparatus for determining the flashing-point of gas-oils is the Pensky-Mar- tens, which is extensively used on the Con- tinent. The oil is gently agitated by small wings on a rotating vertical spindle, while the vapor in the space above the oil is more strongly agitated by a larger fan on the same spindle. The oil-container is heated through an air- bath, and its top is provided with a perforation FIG. 11. Abel's for a thermometer, and a neat device for ad- Flash-test Appa- mitting the flash- jet as required. The test is ratus - conducted very similarly to one with the Abel apparatus. The Pensky-Martens apparatus gives very concor- dant results with the oils of high flashing-point, for which it has been devised. The flashing-point is usually stated in the Fahren- heit scale in this country. "The distillation of a sample of oil gives much valuable infor- mation as to its properties. For most purposes it may be con- veniently carried out in the laboratory in the manner here described. A glass spheroidal flask with a glass tubulure fused in its neck, of capacity twice the volume of the oil to be distilled, is taken, and a thermometer is inserted in the neck by means of a tightly fitting perforated cork, so that the bulb of the thermometer is on a level with the mouth of the tubulure. The latter is connected to a Liebi's condenser. The neck of the flask is lightly held by a clip, and the bottom rests on wire gauze, while the sides of the flask are jacketed with the same material to protect them from air-currents. Heat is applied by means of an Argand or rose burner at first, though towards the end of the distillation a Bunsen may be needed. A convenient quantity of oil for distillation is 500 or even 250 c.c. The flask should be weighed before and after the oil is put in it, and thus the weight of the oil taken is known. The heat should be regulated so that the distillate drops from the en:l of the con- denser at a uniform rate, and does not come from it in a stream. The temperature is read on the thermometer when the oil begins first to pass over, and afterwards as each fraction of the distillate is removed. The distillate is usually collected in fractions amount- ing to 10 per cent, of the volume of oil under distillation. The THE CARBURETTER. 47 specific gravity of each fraction is ascertained approximately. The distillation is pushed until increased heat drives over no more oil, and no residue, or coke only, remains in the flask. When cool the flask is again weighed, and the weight of the residue so found enables its percentage (by weight) of the oil to be calculated. The weight of each fraction of the distillate can be found by direct weighing or from the specific gravity. The total of the weights of the distillates and the weight of the residue should amount nearly to the weight of oil taken; the deficiency, which should not exceed 1 per cent., may be recorded as 'loss on distillation.' It is due to some of the more volatile distillate .escaping condensation. With many oils it is desirable to use two thermometers one for tem- peratures from 20 to 150 or 200 C., the other (nitrogen-filled) for higher temperatures. A thermometer which has been used at high temperatures is not accurate for low ones. The amount of water, if any, which comes over and settles beneath the oily dis- tillate should be observed. The color of each fraction should be recorded, and a piece of moist lead paper held above the outlet of the condenser at intervals to find if sulphureted hydrogen is evolved at any stage of the distillation. The degree of blackening gives an indication of the amount of sulphur in the oil. A note should be made of all observations, and the results of the distilla- tion should be recorded. The determination of the amount of sulphur in gas-oil is seldom made, but can be carried out by Carius' method, or by a slight modification of the fusion methods for sul- phur in coal, or by burning the oil in a suitable lamp and passing the products of combustion through a washer of hydrogen peroxide or other suitable oxidizing agent, and estimating the sulphate as the barium salt. "A good oil for gas-making should be free from water and leave less than 1 per cent, of coke on distillation. A crude oil will generally contain fractions distilling below 100 C., but the dis- tillate now so largely employed for gas-making will be free from such light fractions. A natural oil general^ contains water, though sometimes only in small quantities, and there is great divergence in the boiling-points and specific gravities of the fractions, of dis- tillate from it. Rapid blackening of lead-acetate paper should not take place until near the end of the distillation. Only the tenth fraction should be decidedly dark in color. Oils containing more residual coke than 1 per cent, may be used in certain methods of oil-gas manufacture, but are not desirable in any plant containing checker-work chambers or small outlet pipes. Provided the dis- tillation results do not condemn an oil, it is tested for yield and quality of gas in a small oil-gas apparatus. It is not of great importance which of the mimerous forms of apparatus in common 48 AMERICAN GAS-ENGINEERING PRACTICE. use is adopted, but the same should be used during a series of experiments, and comparisons made with tests of a standard oil in it. Paterson's, Keith's, Pintsch's, or Avery's apparatus may be used. The apparatus should be of a size to work off a gallon of oil in about three hours. The heat of the retort or tubes must be regulated according to the nature of the oil under trial; tests should be made at different temperatures to find that most favorable to the oil. The temperature should be observed with a Le Chatelier or other good pyrometer, but where this is impossible a practiced eye can judge it with fair accuracy. Not less than a gallon of oil should be gasified at each test; the gas should pass through two lime purifiers (2 feet square by 1 foot deep, two shelves) and then through a meter, the index of which should be read before and after the test to find the quantity of gas made. The temperature of the meter should be observed several times during the experiment, and the mean temperature and mean barometric pressure taken for correcting the volume of gas to normal conditions. From the meter the bulk of the gas passes to a works holder, but a small stream of it led to a 15- or 20-ft. holder for testing purposes. The pipes should be thoroughly cleared of air before this sample is collected, and the stream should be such that the holder is filling throughout the test. The sample is tested for illuminating power in the ordinary way, but it will generally be necessary to try several burners to find that most favorable to the oil. The highest candle- power found with any burner should be taken for calculating the value of the oil. Care must be taken that the gas in the small holder is thoroughly mixed; if there is any doubt about its being so, the whole of it should be burned and the photometer tests taken as the illuminating power. As a general rule American oils give the best results at a lower heat than shale oils, and the latter at a lower heat than Russian oils. The results of the tests should be worked out to give the number of candles produced by the gas from a gallon of oil burning at the rate of 1 cubic foot per hour. As the standard rate of 5 cubic feet per hour is too fast for oil-gas, the candle power at the actual rate of consumption is taken , and the nominal candle power at the standard rate arrived at by calcu- lation. The product of the number of candles at the standard rate, and the volume of gas per gallon of oil divided by 5 (the number of feet burned per hour at the standard rate) , gives a figure which represents the ' candles per gallon ; obtained from an oil. This figure multiplied by 3/175 gives the pounds of sperm per gallon of oil. The pounds of sperm per gallon divided by the specific gravity of the oil, and the result divided by ten, gives the pounds of sperm per pound of oil. The results of oil tests are usually stated either in ' candles per gallon ' or 'pounds of sperm per pound ' of oil. THE CARBURETTER. 49 "In the United States of America crude oils are extensively used for gas-making. The specific gravity is about 0.830. As the oil flashes at or little above the ordinary temperature, it is unsuited for transport to a distance. It gives the best result at a moderately low heat. In consequence of the much larger yield of burning oil, American oils produce less intermediate oil on distillation than Russian petroleum affords. "With the exception of petroleum, few oils are worthy of con- sideration for gas-making. The price of animal and vegetable oils is prohibitive; the only others available are the dead tar-oils. As tar is a product of destructive distillation at a high temperature, it is evident that it will not be greatly altered in character by exposure to a high heat. A considerable portion will merely vola- tilize and condense again unchanged on contact with a cool surface. The light benzene hydrocarbons will act thus, likewise naphthalene and other closed-chain hydrocarbons. The green oil from coal-tar, which remains after the extraction of phenols and naphthalene from the middle oils of the tar-distiller, contains a certain amount of gasifiable hydrocarbons and is sometimes used for gas-making. A high heat is required to produce a permanent gas 'from it, and the illuminating power is always low. Coal-tar ' green ' oil yields about 350 candles per gallon. Oil-tar as deposited in the con- densers and siphons of an oil-gas installation contains about a quarter of its volume of intermediate oil, which, when sep- arated by distillation and freed from naphthalene, may be put through the apparatus to produce gas. The yield is, however, only about 300 candles per gallon, and the gas is of dubious permanency. "Hirzel has proposed to take as a standard gas-oil with which results from other oils may be readily compared, one which gives a yield of 60 cubic meters of gas per 100 kilograms of oil; the gas, at a consumption of 35 liters per hour, having an illuminating power of 7.5 standard German candles. Expressed in English terms, such an oil would be one of which 1 ton would yield 21,650 cubic feet of gas, having an illuminating power of 31.86 candles. This gives 137,980 candles per ton, which is considerably lower than the value for most gas-oils in use in this country. A standard of com- parison for gas-making oils, such as Hirzel has proposed, would frequently be of service. " Temperature. The heats of the carburetter can be controlled principally in three ways : either by reducing the heat of the entire set, as by increasing the amount of steam on the generator, or adding a quarter of a turn of down-steam during an up-run, or by reducing the time of the blasting period upon the generator. More directly, the carburetter heat may be affected by reducing either the 50 AMERICAN GAS-ENGINEERING PRACTICE. amount of blast or blasting period, or by " blowing cold/' which proc- ess consists in giving the carburetter a blast considerably in excess of that given the two other retorts. It should always be borne in mind, however, that the heat of the carburetter should be re- tained considerably in excess of that of the superheater; the heat may again be changed by varying the amount of oil admitted. In the opinion of the author, it is extremely inadvisable to heat gas-oil before its admission to the carburetter. Gas-oil being a mixture of oils of various gravities, there is a tendency to break them up at too high a temperature, thereby turning the lighter hydrocarbons into lampblack, beside permitting the carburetter to "run hot "; this danger is less likely to occur with naphtha or crude oil having a regular and constant gravity. Theoretically there is some saving to the bricks of the machine by the prior heating of the oil, but this is a rule more than offset by its attend- ant difficulties. Value of Oils for Qas=making. The effort to utilize coal-tar for carburetting in water-gas manufacture has not been successful, its effect having been unsatisfactory upon the machines, as there is a tendency toward the formation of lampblack. It is main- tained that the best oil for gas-making is that which contains the largest proportion of open-chain hydrocarbons (paraffins and olefins) and the smallest quantity of the ring compounds (aro- matic, etc., hydrocarbons). The latter can be " cracked " or broken up into fixed compounds only at an excessively high tempera- ture, and their illuminating power is relatively low. Generally speaking, gas-oil should be composed as nearly as possible of factors that are homogeneous (as shown by the fractions and dis- tillates coming off within a narrow range of temperature). It will be apparent with this arrangement that at a given heat in the fixing-chambers the oil will not only become completely dissociated, but the fractions will be equally gasified ; whereas, if the contrary were true, certain fractions would become gasified to the destruc- tion or loss of others, the extremes being indicated, as before mentioned, by the production of lampblack or of residual oil or tar. Messrs. Leather and Ross carried on an extended series of experiments (Journal of the Society of Chemical Industry, May 31, 1902), as a result of which they suggest that an approximate valua- tion of an oil for gas-making purposes can be obtained by multiply- ing the number of cubic centimeters of gas produced from 1 c.c. of oil by the sum of the hydrocarbon vapors plus the heavy hydrocar- bons. They give tables of five oils, examined by gasifying in retorts, which may be summarized as follows. THE CARBURETTER. 51 RELATIVE GAS-MAKING VALUE OF VARIOUS OILS. Line No. Russian Solar. Borneo Solar. American Solar. Texas Solar. Russian Refined. 1 2 3 4 Cubic centimeters of gas per c.c. of oil. ... ANALYSIS OF GAS. Hydrocarbon vapors. . . Heavy hydrocarbons . . Methane 465.7 4.0 30.2 54 2 301.0 4.0 22.8 60 442.6 3.2 33.0 52 5 397.4 3.4 26.8 66 2 429.0 3.8 28.0 57 5 Hydrogen 12 13 6 11 6 13 4 11 5 6 Lines 2+3 34 2 26 8 36 2 30 2 31 8 7 Lines 1X6 15 927 70670 16 022 12 001 13 642 Of oils of different types they found that in general those con- taining the greatest proportion of paraffin gave the best results. Operation Details. It is possible in an emergency, where it is necessary to immediately cool the carburetter and superheater for the removal of checker brick, to either remove the oil-injector in the case of the carburetter, or, in the case of the superheater, to intro- duce through the stack-valve a J-in. pipe to which a hose with water supply is connected. After applying the water a short time through the center of the superheater chamber, it may be intro- duced into the sides through the manholes. If possible the water should not be allowed to reach the side and thereby loosen the linings; therefore the water should not be introduced under any degree of pressure. The carburetter in this manner should be cooled within an hour and a half; the superheater within from three to four hours. It does not pay to handle hot brick. In checking the oil received in gas-works the instruments usu- ally used are the Baume coal-oil hydrometer, that has been adopted by the United States Petroleum Association, and Abel's flash-test- ing apparatus. In testing the gravity, corrections for temperature must, of course, be made; it is also necessary in some instances to ascertain the percentage of residue in the oil. The most rapid method is to use a wide-mouthed flask which has been previously weighed and the outlet of which is connected with a vacuum pump, in order that the oil-vapors may be rapidly removed ; after distilla- tion and cooling the flask is reweighed and the residue calculated. It is customary with a number of water-gas engineers to allow a ratio in the carburetter of 250 No. 1 brick (9X4^X2^) for each square foot of surface in the generator. As a rule, the carburetter contains one-third and the superheater two- thirds of the brick ; the total number of fire-brick used for fixing water-gas ; however, depends upon a number of variables. 52 AMERICAN GAS-ENGINEERING PRACTICE. There is a wide difference in practice regarding the pump pres- sure to be maintained upon the oil-nozzle of the carburetter, the extremes employed by various engineers being from 40 to 120 Ibs. It is likely, however, where the Collins injector is used, that too great a pressure will spread the oil into so wide a circle as to strike the wall of the carburetter and will run down without vaporizing ; on the other hand, too low a pressure causes the oil to drop down to the center of the machine, with practically the same result, there being a rapid carbonization on account of the limited area of fire-bricks exposed: the engineer determines by experiment the results best applicable to his conditions. It has also been suggested that with high heats a high pressure and with low heats a low pressure should be used, the vaporization being more rapid or slower under these respective conditions. The oil-storage capacity necessary in a water-gas plant depends upon these factors: first, candle power or enrichment of the gas made; second, the quantity of gas produced; third, the distance of the plant from the points supplied and the facility of communi- cation with the same. Taking into consideration, however, strikes, accidents, and military intervention, the minimum should not be less than a thirty days' supply, from which we obtain the formula for necessary storage capacity: in which a equals gallons of carburetting oil required per 1000 cu. ft. of gas made (usually 5); V= the number of thousands of cubic feet of gas made in 24 hours, t the least number of 'days' supply necessary (generally 30), and G the gallons of storage capacity (generally 6V). The gas pressure lost on passing through the carburetter and superheater depends, of course, upon the shape and number of the fire-brick they contain and also on the pressure upon entering the generator. When the pressure lost in passing through the generator would be six inches, the other two retorts or chambers would have a drop of from 0.5 to 1 inch each, the proportion vary- ing with the spacing and condition of the brick. CHAPTER III. THE SUPERHEATER. ; WHERE gas-oil is in use oily vapors of a dirty yellow color and of an exceedingly disagreeable odor are apt to escape from a machine upon the opening of the superheater stack-valve. This nuisance may be overcome by placing a pilot-light adjacent to the stack- valve, which will ignite these vapors immediately upon their escape from the orifice and permit of their consumption before entering the outside air. Temperature. The heats of the superheater should be main- tained at a lesser temperature than that of the carburetter, for the reason that in the last-named retort the hydrocarbons or illumi- nants are " cracked " or broken up, and that further " cracking " or dissociation tends to deteriorate or break down their value. It will be seen, therefore, that the purpose of the superheater is for fixing or final amalgamation, and for this purpose must be materi- ally less in temperature than its predecessor the carburetter. The heat generally used is a bright cherry in the upper portion of the machine, brightening a trifle at the lower sight-cock. The tendency of most water-gas superheaters is to "run hot." It is possible to reduce such heat by "blowing cold," or giving to the superheater a blast considerably in excess of the other retorts. This is, however, rarely advisable, and the regulation of heat should generally be through the medium of the other machines. The heat of the superheater should hardly exceed a bright cherry at its base, with a duller color showing in its upper sight-cock, a greater heat being accompanied, as a rule, by roaring at the stack. As has been before stated, the heat of the superheater should be invariably less than that of the carburetter, the office of the super- heater being to fix and permanently "set " the gas, and not to further dissociate the hydrocarbons. Perhaps the best test for the proper conditions to be maintained in the superheater is to permit a small jet of gas from the upper sight-cock during the run to impinge, through a very small nozzle, upon a sheet of white and 53 54 AMERICAN GAS-ENGINEERING PRACTICE. preferably unglazed paper. Should the heat of the superheater be too low, tar will be indicated, while a cold carburetter or excess of oil will be reflected by "uncracked " oil being carried over in sus- pense. On the other hand, excessive heat on the part of the super- heater will be shown by deposits of lampblack, and on that of the carburetter by free carbon. The proper condition of heat and " well-cooked oil " will impinge upon white paper a seal-brown stain, varying to amber and slightly glazed. These colors will vary slightly with particular conditions and classes of oil, but, if carefully watched in connection with the results made by the apparatus and the conditions noted, form a most exact index to successful operation. The temperature of carburetted water-gas upon leaving the superheater varies from 1450 to 1600 F., this being dependent upon the heat of the retorts and the nature of the oil used. Carbon Deposits. It is generally possible to remove the carbon from bricks in a water-gas superheater by " burning off." This is effected as follows: The set having been let down and all dust and ashes removed, the doors are closed and a slight blast turned upon the superheater, which is then ignited by means of a little oil and a red-hot iron rod. This slight blast is then maintained until all carbon upon the bricks is entirely removed, the process usually taking some three or four days. It is impossible, as a rule, to work this process upon the car- buretter, inasmuch as the shock attendant upon the intermittent admission of oil has a tendency to fuse or disintegrate the brick, thereby "clogging " thegasway of the machine. Carbon is not formed, as is sometimes supposed, in the take-off pipe of a water-gas superheater ; it merely deposits there, and such deposit cannot be entirely prevented. It can only be reduced in quantity, its presence being detected by continual observation of the wash-box, seat drip-pot, or overflow. Here temperatures are reflected high and low by the presence respectively of lampblack and unfixed oil. The color of crude gas leaving the superheater is affected more or less by the nature of the oil being used. Under average condi- tions and with the oils usually used for carburetting, opening of the superheater sight-cock admits crude gas of a golden straw tinge, without indication of oil or lampblack. Should the escaping gas show a thin bluish tinge, an absence in the proper proportion of hydrocarbons is indicated, while too heavy and dense a cloud, snowing tarry or oily particles, indicates a supersaturation coming from an over-abundance of the hydrocarbons in the gas. The rich straw color and a certain dryness in the gas are under average con- ditions the proper mean between these two extremes. When a jet THE SUPERHEATER. 55 of this gas is impinged on some white substance, such as white unglazed cardboard, it leaves a rich golden straw-colored deposit, without the presence of either tar or lampblack being in evidence. The number of brick in the superheater is supposed to be a certain proportion to the capacity of the generator, between which retorts there should exist a certain balance; as, for example, when the generator is ready to decompose steam the superheater should be ready to fix the gas. This proportion is stated by one authority as follows: The combined checker brick in the carburetter and superheater, exclusive of the side walls, should be 28 sq. ft. per gallon of oil used per hour. A part of this serviceable area is, of course, removed from direct contact with the gas, by reason of the contact surfaces between brick and brick. Therefore the figure is better given as 20 sq. ft. of brick surface per gallon of oil per hour. These figures are based upon the use of the heavier oils, less surface being requisite in the case of the naphthas or higher distillates. Superheater Brick. Split bricks (" soaps"), of course, give greater heating surface for given cubical volumes than the ordinary No. 1 brick, but their use is rarely necessary inasmuch as the fixing surface in modern water-gas machines is generally excessive, and the soap or split brick are weaker and less durable or otherwise desirable than the Standard No. 1. It is the custom of many water-gas engineers to place in the superheater twice the number of No. 1 fire-brick that is allowed in the carburetter. Each set, however, as well as the conditions of operation, such as quality of oil or generator fuel used, length of blast, hour of service, etc., entails different conditions, which can be found only by systematic and careful experiment. CHAPTER IV. WASH=BOX AND TAR. THE action of the wash-box or seal is largely similar to that of a check-valve, to prevent the return of the gas to the apparatus. These seals are generally made with a ratio between the wash-box and the dip-pipe areas of about 25 to 1. It will, therefore, be obvious that if the dip-pipe dips, say, 3 in. in the water of the wash- box, it will require but the rise of 3 in. of water pressure to force the gas through that seal, while before the gas can return from the box into the dip-pipe all the water in the box would have to be forced back into the dip-pipe. Taking the area ratio at 25 to 1, as before mentioned, while it takes but 3 in. pressure to force. the gas into the box, it would require 3X25 = 75 in. pressure to force the gas back into the dip-pipe. (These figures are only approximate.) This same principle can be observed at a coal-gas works in the action of the hydraulic main. Cleaning. The following precautions are advised by the American Gaslight Association committee with regard to the cleaning of a water-gas wash-box: "To insure safety the wash-box and connections must be thor- oughly ventilated. There are two arrangements of wash-box in water-gas apparatus. In one the take-off from the wash-box is on top, and in the other it is on the side and connects directly with the scrubber. The connection from the gas outlet on top of the superheater to the wash-box varies in different forms of water-gas apparatus. In most cases there is a lid on top of what is known as the oil-heater connection, which can be opened to clean the oil- heater. Where no oil-heater is used the take-off connection from the superheater has a hand-hole cross at the top of the superheater, connecting the vertical riser from the wash-box to the outlet branch on the superheater. Where the wash-box has a take-off on top there is a valve between the wash-box and the scrubber, which can be closed and thus shuts off communication between the wash- box and scrubber. In this case, first open either the lid on top 56 WASH-BOX AND TAR 57 of the oil-heater, or, in case there is no oil-heater, the hand-hole on the cross; then shut off the overflow from the wash-box to the seal-pot, open the hand-hole on top of the wash-box, and fill the wash-box with water. When the wash-box has been filled, draw off the water, open the hand-hole or manhole on side of wash-box, and remove the tar, etc. In case there is no valve between the wash-box and the scrubber, but the scrubber and wash-box are joined together by the side outlet on the wash-box, the first thing to be done is to close off the overflow-pipe from the scrubber to the seal-pot. Then open the manhole on top of the scrubber, and then the lower manhole on the side of the scrubber. Fill the wash- box with water as described above. The only difference in the two methods is that in one case you must thorou hly ventilate the scrubber in the manner described. In any case take care that no fire comes near the wash-box or connections while the wash-box or connections are open. Do not use a light abcve the work." Operation Details. The wash-box should be closely watched as a check upon the heats in the carburetter and superheater. If lampblack is being produced it will show here, as will sometimes naphthalene, which, however, is more apt to appear in the multi- tubular condenser and the inlet of the purifiers; on the other hand, low heats, excess or unfixed oil will appear in the shape of free oil on the surface of the seal-pot. The safety line lies about the exact center of these extremes, as indicated by clear tar, showing with reflected light a tinge of yellow gold, its exact consistency and color being dependent somewhat upon the nature of the oil used. To repeat, however, the best test of properly fixed gas is the clarity of the tar at this point, which should be absolutely free from either lampblack or uncracked oil. The inflow of the wash-box is generally regulated so as to admit from 7 to 11 gallons of water per 1000 cu. ft. of gas made. The question of increased candle power through illuminants picked up in repumping of the seal-water is much debated. There is probably some recuperation from the lighter oil, but little or none from the tar, which is better extracted by a skimmer or baffle-separator introduced into the system. There are certain little advantages in the use of fresh water in the seal, as it more readily combines with CO2 and the sulphur compounds. This is more than compensated by the high temperature usually existing in the seal-water, the water in good practice in any event never being admitted to the seal at a less temperature than 110 F.; moreover, it is likely that, in usmg the old water, it has already reached a point of saturation for both gas and the light hydrocar- bons with which it mechanically combines, it therefore ceases to take these from the gas passing the seal-pot. The best practice 58 AMERICAN GAS-ENGINEERING PRACTICE. requires, therefore, that the seal-water be returned to the seal by the use of a circulating pump, having separated from it all tar, etc., which is heavier than water. The undecomposed steam in the gas should also be utilized here, and condensing should about com- pensate for any losses in water, thereby obviating the necessity for any fresh water in the seal-pot system. The pump used should be of special design for handling hot water and oil, and should have a capacity of at least 50 per cent, in excess of its maximum demand. A rapid circulation should be kept up in this water, the pump being arranged to run slowly. Where tar separators are used the suction-pipe should be placed about 5 ft. below the surface in the last section of the separator, and the pump may then force directly into the seal-pot. Composition of Tar. O 'Conner, in his Gas-engineers' Hand- book, gives the amount of water contained in oil-gas tar upon leav- ing the apparatus as being 70 per cent. The following tar analysis is taken from the work of Paddon and Goulden. The specific gravity of the tar was 0.996. Per Cent. Per Cent, by Volume by Volume. Without Water. Water 76.5 0.00 Benzine 0.28 1 . 19 Toluol 0.90 3.83 Light paraffins, etc 2.0 8.51 Solvent naphtha (xylol) ... 4.15 17 . 96 Phenol trace trace Middle oils (naphtha, etc.) . 6 . 92 29 . 44 Creosote oil and green oil . . 5 . 70 24 . 26 Naphthalene . 30 1.20 per cent, by weight Anthracene coke 0.22 (contains 8.33 0.93 per cent, anthracene) Coke.. 2.30 9.80 99.27 97.20 Loss. . 0.73 2.80 Total 100.00 100.00 The following is an analysis of water-gas tar from the Mutual Gaslight Company of Savannah, Georgia: Specific gravity at 60 F 1.1284 Free carbon 9.84% WASH-BOX AND TAR. 59 DISTILLATION PRODUCTS, PER CENT. BY WEIGHT. Ammoniacal water 0.15 Oils, light 170 C 9. 18) Middle 25.81 [ 62.76 Anthracene 27 . 77 J Pitch 33.90 Loss in analysis 3.19 100.00 Tar Paint and Pavements. The two principal uses of oil-gas tar are, first, as a paint; and, secondly, as a paving. Its prepara- tion as a preservative coating for pipes and metals we have described under the head of Services. In ordinary paint for woodwork it may be boiled down to such a consistency that it will " string" between the thumb and fore- finger. It should then be heated to about 150 F., and benzine added at the proportion of 1 gallon of benzine to 4 gallons of tar. No more of this preparation should be made up at one time than is required for half a day's work. A method of utilizing oil-gas tar, which has been employed by several companies and has been of considerable profit, is as follows: An oil-boiler has been connected with the tar- well, a tar-pump being placed in series therewith. This boiler is made tight, and to the top is fixed a pipe coil acting as a worm and ending in a suitable water-condenser. The boiler is pumped about half full of the watery tar as it reaches the well. All connections, save the end of the worm, are then closed and a fire started beneath the boiler. Evaporation takes place very rapidly, the worm first passing off aqueous vapor, then anthracene, and finally a fair quality of creosote. The residual left in the boiler or body of the retort is a fair quality of what may be termed oil-pitch, a commodity having much greater value as a preservative, painting, or roofing material than has the ordinary oil-tar. The following formula for making tar pavements or side- walks is given by a committee of the American Gaslight Associa- tion: "For pavement or sidewalks applied as a finishing surface 2 to 3 in. thick upon a foundation of broken stone or coarse clinker, the top dressing of finer ashes or coke breeze, boil the tar until at 60 F. it has the consistency of vaseline. In the absence of special furnaces for the work place a sheet of boiler-plate upon stones in 60 AMERICAN GAS-ENGINEERING PRACTICE. the vicinity of the paving to be laid, so that it will be about one foot above the ground. On this plate throw building sand and underneath kindle a fire of wood or coke. Turn the sand over with a shovel until well heated. Gradually pour on the thick tar, mean- while turning and mixing the mass until the sand is uniformly black and of such a consistency that a ball of it will just hold together while hot. While hot and carrying the mixture in heated iron barrows or on shovels, apply where required, leveling with a hot rake and ram with a hot rammer. Then sprinkle the surface with' fine sand and roll, using preferably a heavy hand roller. This may be made of a piece of cast-iron street main, with ends plugged and center filled with sand." Tar=pumps. In connection with the handling of tar and con- cerning the proper pumps for the transportation of same, the committee also has to say as follows : "The principal points of valve design to be observed are that the valves should afford full, free openings, and that the seats should be so arranged that no lumps of heavy tar or of solid matter in the tar will lodge on them and prevent the valves from closing tightly. A hinged valve is better than the ordinary form of pump- valve, since in the latter form the center guide obstructs the opening to a great extent, while the hinged valve affords a free and unob- structed opening. These valves are sometimes used with horizontal seats and sometimes with seats inclined at an angle of 45. With the inclined seat there is less danger of any solid matter remaining on the seat and keeping the valve open. "One company that handles a great deal of tar employs pumps in which the valves are hinged and the seats horizontal, and says that they have found them to give complete satisfaction. In this case the valves are not provided with springs, being prevented from opening too far by stops and being closed by their own weight as soon as the pressure is removed from beneath them. In other pumps springs are used with the same kind of valves to keep them from opening too far and to assist in closing them promptly when the plunger changes the direction of its travel. These springs should be made of iron or steel." In handling tar a slow-running pump, preferably of the rotary type, should be used, with non-restricted orifices, all parts easy of access for repairs or cleaning. The internal resistance of the pump, by which is meant the resistance offered to the passage of the tar, should be a minimum. If, however, the reciprocating type of pump should be used, it should be entirely of iron or steel with ball- or trap-valves and with extra large inlet and outlet. The long stroke-pump will be found preferable, and the size selected should be at least double that of an equal capacity for water. UNIVERS1 WASH-BOX AND TAR. 61 Separation. There are two occasions when tar should be con- densed or separated from its accompanying medium; the first, that of tarry vapors in the gas, which continue as far as the puri- fiers and greatly injure the purifying material by covering it with a thin, oily insulation, and which may be remedied by placing in the inlet of each box a layer of planer chips, or, better still, by devoting the first box in the series entirely to chips and shavings, these to be changed immediately upon becoming foul. The other occasion is the separation of the tar from the water with which it leaves the condensers, scrubbers, or seal-pot. This separation is extremely advisable, both for the preservation of the tar and the rendering of the water fit for renewed use, and also because, in case the water, either as a whole or in part, is not used again or finally finds its way to the works drains or sewers, it should be free from all tar and heavier oils, which are of incalculable detri- ment to it. It is the custom of many cities to prohibit the running of tar into their sewerage systems, and inasmuch as it discolors any neighboring watercourse its disposal through drain- age invariably becomes a considerable incubus. For the separation of the tar from the water, however, under conditions such as we have just recited, a form of separator or FIG. 12. Tar-separator. skimmer is illustrated in Fig. 12. This is little else than a long, oblons; trousfh, in which the greater the width the better, the veloc- ity of flow being thereby decreased. In this trough are placed lat- eral partitions or skimmers marked a. The intervals between them are about 18 inches. Alternate partitions reach from a foot above the water-line to within a foot of the bottom of the box, while intermediate partitions reach from about 4 inches from the bottom of the box, or through to a point, say, 4 inches beneath the water- line. The sides of the trough should be equipped with proper bungs for drawing off the tar, and to insure perfect separation the outlet of the trough should be so arranged that a strainer of bag- gins; or fine wire netting can be applied, cotton bagging being a very good material. In addition to the above separator it is well to have upon the outlet a trough which may be filled loosely with pieces of coke, which will be found an excellent strainer, as the 62 AMERICAN GAS-ENGINEERING PRACTICE. rough side of the coke adheres to the passing tar which attaches to it and serves to give the water its final purification. The coke should be maintained in a cleanly condition, the fouled coke being burned. A limited amount of water-gas or oil-tar can be used to some advantage on the generator of a water-gas set, and will be found to have an enriching quality of between 5 and 6 candles per gallon. Not more than one-half gallon of tar, however, should be admitted to 1000 cu. ft. of gas manufactured. The tar should be pumped into the top of the generator preferably with an oil-spray, similar to that used on the carburetter. The West Chester (Pa.) Gas Co. is using a cream-separator, such as are used by dairies, for the separation of water-gas tar from its entrained water. A similar separator for this purpose is made by Messrs. Geo. Shepherd Page Sons in England. jccnoir Vr ire*/* IHJCCTO* rat eufnea. FIG. 13. Steam-spray Tar Burner. Burning Tar. The chief disadvantage in using tar in com- bination with oil as an enricher appears to be the clogging of the checker brick in the carburetter and superheater, so the more gen- eral practice appears to be burning the tar under the boilers, which is generally accomplished by the ordinary steam-jet spray before described. An excellent method for preparing tar for this usage is by the use of two tanks, in the larger of which a large steam-coil is inserted, by which the water is evaporated, thus leaving a pure oil-tar residual. This tar is then drawn off into the second tank, from whence it is fed directly to the burner. The levels of these WASH-BOX AND TAR. 63 tanks should be arranged, if possible, so that this last operation may be performed by gravity. It is stated that 2.6 gallons of oil- tar are equal to a bushel of coke as fuel under steam-boilers. A form of burner is shown in the illustration (Fig. 13). Newbigging's Handbook gives 6 gallons coal-tar as being the equivalent of three bushels of coal when properly fired under a boiler. CHAPTER V. SCRUBBERS. As a matter of fact the seal-pot or wash-box is the first in the series of purifying apparatus in a water-gas setting, but the passage of the gas is relatively so rapid at this point as to make its action extremely imperfect, and the first heavy duty in cleansing and purification devolves upon the scrubber, which succeeds the wash- box in series and precedes the condenser. Operation Details. Great care should be taken with the regu- lation of water in this apparatus, as a surplus tends to wash out and carry off mechanically the heavier hydrocarbons. This water should usually be the overflow from a multitubular condenser, unless this should run too high in temperature. A fresh-water connection should always be available for such occa- sions, when a sufficient amount of cold water may be admitted to lower the gas to the degree required, namely, about 170 to 190, at the outlet. The material used to fill scrubbers is generally that presenting the greatest possible surface to the action of the gas and water. King's Treatise recommends the use of small stones, pebbles, coke, brickbats, tiles, or timber. Of these materials coke is perhaps the best by reason of its lightness, although it has a tendency to crumble should the height of the column be sufficient to produce a crushing weight. Trays. Sir George Livesey is responsible for the method of using trays of thin boards J in. thick, 3 in. high, and spaced 3J in. apart, having an area proportioned to the diameter of the scrubber. The most common practice is to use boards f inch to J in. thick, 4 inches to 10 in. high, and made up with about J-inch spaces between. These trays are placed horizontally within the scrubber, tier by tier, in a manner known as "thatched," or one tier placed so that its length is at right angles to that of its predecessor. Props or supports are usually placed at certain inter- vals to allow the gas to redistribute and to facilitate the removal 64 SCRUBBERS. 65 of a portion of the tray without removing the entire contents. The relative merits of such trays as described and those of coke are about as follows: For the coke, lightness, cheapness (the coke may be burned after it becomes saturated), and the convenience of the installation. That claimed for the boards or trays, freedom from stoppage, ability to be cleansed and used again, greater contact service for ware/twee!.. j>tpnoninG FIG. 14. Water Distributors for Tower Scrubbers. both gas and water, slower speed of travel of gas, greater efficiency for space occupied. Sir George Livesey gives the following comparison of mate- rial for each cubic foot of space occupied: Contact surface of coke, 8J sq. ft. per cu. ft. Contact surface of boards, 31 sq. ft. per cu. ft. Coke occupies J cubical contents. Boards, J", spaced 1" centers, occupies J cubical contents. Sprays. The greatest difficulty to be overcome in wet scrub- bers is to obtain an even distribution of the water-spray over the 66 AMERICAN GAS-ENGINEERING PRACTICE. material. There are for this purpose a number of devices, some of which are movable, as the tourniquet pattern (see Fig. 14). But perhaps the more practicable are such devices as the Gurney jet and the radial spray, as illustrated. These last-named should be carefully regulated as nearly as possible to throw an equal amount of water evenly distributed over the entire area of the scrubber. Water Analysis. In water analysis for all practical pur- poses, it is customary to divide the operation into two parts: 1. Total Incrusting Solids: Oxide of Iron, Calcium Carbonate, Calcium Sulphate, Magnesium Carbonate, and Magnesium Sul- phate. 2. Non-Crusting Solids: Magnesium Chloride, Alkaline Car- bonates, Alkaline Sulphates, and Alkaline Chlorides. In a rough-and-ready analysis it is usually enough to begin with, say, muddy water, settled; decant, weigh sediment; filter, weigh suspended matter. Take 250 c.c. filtered water and titrate with decinormal HC1, using methyl orange as indicator. This gives total alkalinity of carbonates. To the same sample add excess NH 3 , precipitating A1 2 O 3 , Fe 2 O 3 , and most of the SiO 2 ; fil- ter, ignite, and weigh oxides. Precipitate calcium in this sample with ammonium oxalate; filter, ignite, and weigh as calcium oxide. To the filtrate add sodium phosphate and more ammonia; filter, ignite, and weigh; calculate as magnesia. To this filtrate add HC1 and BaCl 2 ; weigh as barium sulphate and from it calculate the sulphuric acid. On a second 250 c.c. sample, determine chlorine by titrating with standardized silver nitrate, using potassium chromate as indicator. The probable combinations may be worked out thus: Calcu- late all magnesium as carbonate (if excess of magnesium remains, calculate as sulphate); combine excess of CO 2 with calcium (if further excess of CO 2 remains, combine with sodium); calculate remaining calcium as sulphate, remaining sulphuric acid with sodium, and chlorine with sodium. This is applicable to boiler waters and gives reasonable accuracy. CHAPTER VI. CONDENSERS. THERE is, perhaps, no item in the manufacture and distribu- tion of gas more important than its proper condensation. This should lie between two limits. The first, and probably more im- portant to avoid, the sudden cooling of the gas, contracts the vapor and causes a precipitation of the benzol vapors and heavier hydrocarbons; the second requires that all condensation should, if possible, be removed from the gas before leaving the works, as otherwise stoppages in the mains, produced either from the low heat in the machine, causing tar, or the high heat, forming naph- thalene and lampblack, will invariably ruin the meters, causing the diaphragm to become hard and stiff, closing services, reduc- ing pressure, forming traps, and especially affecting Welsbach or incandescent burners. Temperature. In order to obtain proper condensation a care- ful study of the prevailing conditions must be made in each case and test of the temperature of the gas made at various junc- tures in its passage through the works. The writer suggests the following approximate temperatures which should follow as the result of gradual condensation: Outlet of Deg. F. Wash-box 220 Scrubber 170-190 First condensers 120 Relief-holder 70 The last depends somewhat upon the temperature of the atmos- phere. It is manifest that in order to prevent shock or sudden chill to the gas the coolest gas and the coolest water should be brought into contact; for example, cold water only should be turned 67 68 AMERICAN GAS-ENGINEERING PRACTICE. into the last condenser, the overflow from which goes back into the scrubbers and in turn into the seal-pot, thereby causing the current of water to flow in opposite direction to the current of gas, the water gradually warming and the gas gradually cooling so that the water at the seal is almost of an identical heat with the gas, being warmed throughout its passage; while at the relief- holder the gas is of a temperature identical with that of the water, being cooled throughout its travel. Jas. S. Mcllhenny, engineer and superintendent of the Wash- ington (D. C.) Gaslight Co., has designed a system of condensing / FIG. 15. Method of Ascertaining Temperature of Gases. apparatus which very nicely proportions and graduates this cool- ing process, and which, through an easily controlled mechanism, accurately and mathematically apportions the exact amount of cooling surface necessary to the gradual cooling of any given amount of gas. This apparatus is capable of accommodating itself to a very large or small quantity of gas output. Surface. As to the amount of condensing surface necessary to properly cool a given amount of gas, authorities differ very widely. Butterfield, one of the best English authorities, gives 150 to 200 sq. ft. condensing surface per 1000 cu. ft. of gas passed per hour. Newbigging gives 10 sq. ft. per cu. ft. per minute. Perhaps one of the best is Raissner's rule of 3.65 sq. ft. of cooling surface per 1000 cu. ft. per 24 hours as a minimum and 4.56 sq. ft. per 1000 cu. ft. as the best practice. The above calculations were made for atmospheric condensers. In multitubular water-condensers, wnere the difference in temperature between the gas and the cooling medium can be regulated by the amount of water admitted, the amount of sur- CONDENSERS. 69 face depends naturally upon the reduction in temperature re- quired. Suppose it were necessary to lower the temperature of the gas 63 (that being the extreme difference in temperature between the gas and the water at the gas-inlet of the condenser) to an average difference of 36.5 F., it would then be necessary to have 1.71 sq. ft. of water-cooled surface and 1.19 sq. ft. of air-cooled surface per 1000 cu. ft. of gas per day. If the water is passed through the tubes and the gas outside the tubes in the condenser, then the shell usually affords about 1 sq. ft. of air-cooled surface in addition to the water surface. When the gas is passed through the tubes there is no air-cooled surface except the small amount around the gas spaces at the top and bottom. These condensers will show average differences in temperature between the gas and the water of over 10 F., and their great difficulty, as is almost invariably true with all water-cooled systems of condensation, is that the chilling of the gas is too sudden and a precipitation of the illuminants thereby results. The writer is of the opinion that the burden of testimony is to show that at least 8 or even 10 sq. ft. of water-cooled surface should be installed for each 1000 cu. ft. of rated maximum capacity per day of the condenser, and that, such apparatus being at the command of the works engineer, he should then closely watch the temperature of his gas throughout its course, and, by the proper admission of water into the water-inlet of his last condenser, main- tain a gradual and equal cooling throughout the entire process. A. G. Glasgow in 1892 made the statement that it required 90 gallons of water per 1000 feet of water-gas manufactured for condensing, cooling, and scrubbing. Of course the amount of water required for condensing gas to any given temperature will depend largely upon the area of the condenser and atmospheric conditions. Essential Principles. Next in order to the recuperation of heat lost from water-gas sets as an economic condition, the subject of condensation is most important; it is but little understood, and, moreover, is so dependent upon local conditions, environment, cli- mate, etc., as to make impossible any arbitrary procedure in the mat- ter. It is conclusively proved that deposits of naphthalene, freezing of services, and the various troublesome stoppages are positively prevented by the thorough drying of the gas, and it is doubtful if any engineer properly realizes the improvement in service rendered, especially along the line of incandescent lighting, the maintenance of meters, etc., that would ensue upon the establishment of a per- fect system of condensation. Broadly speaking, in the opinion of the writer, this would be along the following lines: 70 AMERICAN GAS-ENGINEERING PRACTICE. The passage of the gas should be slower at the commencement of its condensing course, and its impinging during the mechanical portion of its passage should be less violent than later on, where the gas has attained a somewhat lower temperature. To effect this the velocity of the gas should be slowest at the beginning of its passage, gradually increasing in speed throughout its course. As it gradually decreases in temperature there is a shrinkage in vol- ume and a corresponding precipitation of both aqueous vapors and hydrocarbons. The loss of the latter is considerably less where the temperature is reduced very gradually and the direction of the flow of gas and water arranged in reverse directions. It must be remembered that the affinity of gas for water at any temperature is very great, and that it will take up and recombine with substances at any stage of manufacture or distribution, the principal points of contact being the hydraulic main, seal-pot, scrubbers, purifying-boxes, station meter, and the water-seals of the holder, the last named being much more important than is commonly realized. The writer therefore suggests greater condenser capacity with a slower rate of flow, and a condenser, dry scrubber, or shavings purifier containing some absorbent to be placed at the outlet of the storage-holder or immediately adjacent to the distribution outlet. This would allow but one remaining chance for the reab- sorption of condensed materials, such as are found in the drips along the mains. These drip-pots should be maintained as clear and free from deposits as possible, a matter which would not prove difficult where the gas handled is dry and originally free from moisture. As has been before said, the theory of condensation requires that, with each degree of decrease in temperature on the part of the gas, a portion of aqueous vapor or water be deposited; and that this shall be done gradually and without excessive friction upon the gas, so that the hydrocarbons will not be disturbed, is the fine art of proper condensation. As will be seen, this deposit- ing of water on the descending scale of the thermometer is theoret- ically directly the reverse of fractional distillation. Unfortunately this does not work out completely in practice, for two reasons, viz. : first, that in this precipitation the entrained hydrocarbons are mechanically separated; and, second, the aforesaid affinity of gas for water under any condition tends to its recombination at any period of its travels; also the volume of the gas may be due to pressure as well as temperature. The point of complete saturation of gas for hydrocarbon vapors is extremely uncertain, the behavior of the gas being different under varying conditions, environment, and pressure. It would seem that a system of dry condensation CONDENSERS. 71 would be extremely advantageous, which would afford the gas no opportunity to recombine with moisture, for this recombination and subsequent precipitation constitutes a washing process which eventually removes from the gas a considerable proportion of its hydrocarbons. The difficulty has been that any dry desiccating material, during its first stage of use or when first renewed, would act too harshly upon the gas, mechanically stripping it of many of its valuable contents; while later on, when permeated with these ingredients, it would reach the point of saturation and cease to act at all. A material, if found, which would maintain for any length of time the mean between these points, would prove a valuable aid to purification. There is no doubt, however, that the gas when leaving the works should be perfectly fixed and dry, and to this end the writer again urges the efficiency of a proper condenser at the outlet of the storage- holder. The improvement in service gained through the supply to the consumer of a perfectly dry gas is most marked not only by the avoidance of naphthalene and various deposits, and the damage done to the diaphragms of meters, incandescent mantles, ranges, etc., but the removal of moisture promotes a very consider- able increase of candle power, in addition to which the flat-flame light is whitened and materially improved in color and luminosity. This feature has been proved by experiments in high-pressure transmission, results showing that about 65 per cent, of moisture can be taken out of the gas by 10 Ibs. per sq. in. compression, while at 20 Ibs. pressure practically all moisture disappears. Pro- portionately, however, the greatest amount of moisture is removed up to and by a compression to 6 Ibs. per sq. in. CHAPTER VII. PURIFIERS. Testing for Impurities. The following are the simplest quali- tative tests for ascertaining the presence of impurities in gas: For carbonic acid allow the gas to bubble through lime-water; if present the water will become thick and cloudy. For H 2 S impinge the gas through a pet-cock on a piece of paper which has been wet with acetate of lead (sugar of lead) in solu- tion; its presence (H 2 S) will be indicated by the discoloration of the paper, a shade of brown appearing, the amount of the discolora- tion depending upon the quantity of sulphureted hydrogen con- tained in the gas and the length of time given to the exposure. A similar test to that for H 2 S is made for the presence of am- monia, only turmeric paper is used instead of acetate of lead. The test for tar is usually made by permitting a stream of gas to impinge upon a piece of white (and, better, unglazed) paper. If the paper receives a dark, dirty, or tarry stain, the presence of tar in the gas is indicated. A continuous test for tar may be made by passing a stream of gas through a test-tube loosely filled with cotton-wool, in which case should tar be present the wool will become discolored. The places at which these tests should occur are usually such situations as would indicate the complete or imperfect gas purifica- tion, as, for example, the test for ammonia would be the outlet of the last scrubber or washer; that for CO 2 and H 2 S generally at the last purifying -box in the series; and that for tar at the outlet of the tar-extractor, condenser, or even the sight-cock in the super- he^ater. It is sometimes necessary, however, to make tests for tar and other condensations (for which purpose the cotton-wool test is preferable) in the center of the distribution system, or at the fixtures of some consumer; this is necessary when tar, naphtha- lene, or other mechanical impurity is causing trouble to gas arcs or other incandescent-lighting burners. Purify ing -houses are not an absolute necessity, as it is possible 72 PURIFIERS. 73 to maintain the boxes at a proper temperature by means of a steam-coil, although it is the experience of the writer that even in the colder climates the chemical action occurring in the box gen- erates sufficient heat to deliver .the gas at the outlet at an equal temperature, if not greater, than that at which it enters the box. For exposed work, however, he strongly recommends boxes of the Doherty-Butterworth type. The maintenance of such boxes is practically reduced to the annual painting, and the danger of explo- sion, due to the formation of explosive mixtures in purifying- houses, is entirely obviated. Leaks. In leaks in holders and purifying-boxes occurring be- tween the lap of the plates where such plates are too thin to calk and inclined to buckle and separate, a temporary stoppage can be made by rolling tin-foil into small rolls and calking in between the plates with a sharp tool, after which the whole should be heavily shellacked. Precautions. Explosions have often occurred in purifying- houses through the breaking of incandescent-light bulbs. This should be guarded against. Lamps have been successfully used with a double screen, increasing the size of the wire one-half. Preservation. A film of heavy petroleum or lubricating-oil carried upon the seals of purifying-boxes tends to prevent the rusting of their sheets. Sulphur Removal. The chief reason for eliminating sulphur and sulphurous compounds from gas is the fact that they burn to sulphurous oxide, a compound disagreeable to breathe and on some occasions forming exceedingly small quantities of H 2 SO 4 . The amount of sulphur in gas, however, as ordinarily purified, is too small to be appreciable. The two methods of purification most commonly in use may be stated as 1. Purification where the material is handled for revivifying, and 2. Revivifying in situ. It is not the desire of the writer to discuss the various advan- tages of these two methods ; they depend for their adoption largely upon the relative cost of labor and installation. In the in situ method probably the best plan is to connect a small air-pump, such as that made by the Connelly Iron Sponge & Governor Company, in such manner that somewhere in the neighborhood of 1 per cent, of air is admitted into the purifiers with the gas and thus revivifies the oxide from the effects of the sulphureted hydrogen. Even with this method, however, the oxide must be periodically changed, as it becomes foul with tar and oil; also the, moisture in the gas eventually causes the 74 AMERICAN GAS-ENGINEERING PRACTICE. oxide to crystallize and become hardened, thereby materially increasing the back pressure. Purifying Material. Where it is desirable merely to remove from the gas sulphureted hydrogen, oxide of iron can be manu- factured cheaply and of good quality as follows: A large quantity of clean gray iron borings, free from steel, brass, and other metals, should be put in a trough similar to those used for mixing con- crete. To every 500 Ibs. of these borings 20 lbs v say, of crys- tal rock salt may be added and the whole wet down by throwing on buckets of water after the manner of slaking lime. The mix- ture should then be turned with a fork and again wet daily, all lumps and hard particles being broken up, sifted, or thrown aside, until oxidation is complete. It may then be mixed with clean shavings containing no pine rosin or other gum, at the ratio of 56 Ibs. of the oxide of iron to a bushel of the mixture. In those instances where it is regarded advantageous to re- move carbon dioxide from the gas (in regard to which see table on Effect of CO 2 on Candle Power), lime must be used and should be slaked after the following manner : A layer of the best lime, say 5 in. thick and unslaked, should be evenly spread on the floor of the trough as described above. It should then be wet by throwing on buckets of water. At no time should a hose be used, as the largest possible quantity of water should come in contact with the greatest surface of lime simultaneously. Small jets of water tend to slake the lime unequally and to make it hard and full of lumps, besides causing a large portion to be burned out and inert. The iron borings used for reduction to oxide of iron may be tested by passing through a screen with a mesh not greater than J- in. Borings, obtainable from the average machine-shop, are coated with lard-oil, or other grease used for the lubrication of the cutting-tool. This oily coating serves as an insulation against oxidation, but can be in a degree overcome by the mix- ture with the borings of unslaked lime before their wetting with water or brine. Capacities of Purifiers. In purification the slowest possible velocity should be obtained in order to permit time for chemical combination. It should not materially exceed in. per second, considering the box empty. The purifying material generally occupies about three-fourths of the contents of the box, leaving one-fourth for voids. The gas will therefore actually pass through these voids at a velocity of about f in. per second. One of the largest gas-engineering concerns in America con- structs its boxes for ordinary conditions upon the following cal- culations: Taking a velocity of in. per second for the area of PURIFIERS. 75 a purifying-box (which is equivalent to a velocity of 1440 ft. per 24 hours), each square foot of purifying area can purify 1440 cu. ft. per 24 hours. The following table of capacities has been figured from the above and will be found satisfactory for or- dinary conditions: Size of Boxes. Approximate Capacity per 24 Hours. Feet. Cubic Feet. 6X 8 70,000 8X 8 92,000 8X10 115,000 8X12 138,000 10X10 144,000- 10X12 173,000 12X12 207,000 12X16 276,000 16X16 369,000 16X20 461,000 20X20 576,000 20X24 691,000 24X24 828,000 24X30 1,037,000 30X30 1,296,000 30X36 1,555,000 The above capacities are for ordinary conditions and for proper depth of purifying material when oxide is used, the active oxide being between four and five feet in depth. It will be noted that almost all the empiric formulse given for ridding crude gas of H 2 S are based upon coal-gas purification, and inasmuch as coal-gas contains from 400 to 800 grains of sul- phur compounds and carbureted water-gas contains only about 10 to 15 grains of the same per 100 cubic feet, a smaller area for purification will serve in the case of water-gas than that desig- nated by old authorities. Clegg's rule for the area of purifiers was 1 ft. area for every 3600 cu. ft. made per day. Newbigging's rule for the area of purifiers is: The maximum daily make multiplied by 6 and divided by 1000 equals the num- ber of square feet area in each purifer. Anderson's rule for lime purifiers was that the rate of flow of gas through the purifier should not exceed 2000 cu. ft. per foot of surface per 24 hours. As to construction, the thickness of cast-iron purifier plates should never be less than f of an inch, and they should be the 76 AMERICAN GAS-ENGINEERING PRACTICE. best quality of casting. The usual width is 5 ft. Flanges for bottom plates should be 2 f in. by f in. over and above the thick- ness of the plate. Strong brackets should be fixed under each lute, as the strain is greatest at this point. Larger plates than 5 ft. square are liable to warp in casting. The depth of water-seal in purifiers varies from 12 in. to 30 in., the width from 4 in. to 8 in. As a matter of fact the seal should never be less than 18 in. A formula for calculating the size of connections on purifiers is as follows: Diameter of connections in inches equals the square root of the area of purifiers. The economical depth of oxide seems to be between 4 and 5 ft., regardless of the area of the box. As a matter of fact the installation of purifiers beyond a cer- tain extent is largely a matter of first cost. Where it is practicable to make the expenditure, the four-box system, having a center valve by which any combination of three can be made, is most advantageous. The purification of gas is a dual process, being partly mechanical and partly chemical. For example, the sulphur is removed by chemical union with the oxide, while tar, oil, and condensation are removed by impinging upon the purifying mater rial. It is, therefore, a marked advantage to have an ample equipment affording sufficient area for purification and at the same time enabling a reserve, so that while one box is thrown out, the balance of the equipment is ample to carry on the work. This throwing out or cleaning should be done in rotation, making connections permitting of any possible combination between the boxes. j In passing gas already purified through foul oxide it is pos- sible to pick up impurities in transit, such as CS 2 . It is, there- fore, manifest that the passage of the gas should be so conducted as to pass the foul gas first through the dirtiest box, or that least recently cleaned. It should then pass through the boxes in such order as to leave the cleanest box last, it being arranged, if pos- sible, that the last box in the series be kept as absolutely clean as practicable, thereby removing from the gas any impurities which may remain in it due to a surcharge or a lack of combining strength of the oxide in the preceding boxes, which may, possibly, have passed the point of chemical saturation. In many works it is customary of late years to build concrete purifiers, these having the advantage of cheapness and extreme durability. It is also possible to build these out of doors, thereby effecting a saving of floor-space inside the works, lessening the orig- inal cost of buildings, etc. These boxes are not as convenient for the handling of purifying materials as the elevated box. High boxes PURIFIERS. 77 greatly facilitate the labor in removing and replacing the oxide during revivifying where the in situ method is not adopted, as they are built with dumping-trays and cleaning -valves which enable the workmen to readily drop the entire contents upon the floor below. This floor, by the way, should be either of concrete, cement, or brick, by reason of the great heat attained by the sulphur in the oxide during its recombination with oxygen. In fact, all portions of the purifying-house should be well ventilated and as nearly as possible fire-proof. Nine-tenths of the explosions occurring in gas- works happen in this department, the danger being greatly dimin- ished where there is free ventilation, and where any gas escaping through blowing -boxes, evaporation of water from the lutes, leaks, etc., does not have an opportunity to collect in sufficient quantities to form an explosive mixture. Only electric incandescent lights should be permitted in purifying-houses. Where they can be used, reversing valves or center valves are unquestionably of great advantage over the old and complicated multiple-valve system, and will be found a great economizer of space and time. Making Oxide. The following synopsis of purification is taken from one of the publications of the Gas Machinery Co. : The sesqui- hydroxide of iron, Fe2(OH) 6 , is the most active form of " oxide," but is very unstable, decomposing when heated to about 100 and forming Fe2O3.3H2O. This last compound forms the most active constituent of "oxide," combining with the sulphureted hydrogen in or Fe 2 O 3 .3H 2 O +3H 2 S = 2FeS +S 2 4-6H 2 O. The bulk of the sulphureted hydrogen is absorbed according to the first equation, probably about one-fifth according to the second equation. Various methods are used to make oxide, the principal object being in every case to obtain the ferric oxide in as fine a state as possible and intimately mixed with soft-wood chips, shavings, or sawdust. Pine or spruce shavings are best, as they contain no objectionable tannic acid found in oak, poplar, or whitewood. An oxide should always be alkaline. Method 1. Mix clean fine cast-iron borings with sal-ammoniac in proportion of 20 Ibs. to 1 oz., distribute on floor in layer of about 6 inches, and allow it to rest for at least three weeks, turning and wetting the borings every few days. Mix with soft-wood shavings or chips, previously wetted to make material weigh about 40 Ibs. per cubic foot. 78 AMERICAN GAS-ENGINEERING PRACTICE. Method 2. Mix coarse sawdust or small chips with slaked lime in proportion of four barrels of sawdust to one of lime. Pour cop- peras dissolved by steam over same, using about 9 pounds of copperas per bushel of shavings. Dissolve 1 Ib. sal-ammoniac in water and mix with 20 Ibs. of iron borings. Then mix sawdust and lime with borings. Method 3. Spread pine shavings in a layer of about 18 inches; cover with 3 inches of previously rusted cast-iron borings, sprinkle with salt water and mix thoroughly, turning over every day for about one week. It is good practice in the manufacture of purifying material to mix the sawdust or shavings with the iron borings prior to oxidiza- tion, so that the iron in rusting forms a coating or crust upon the shavings, and is better retained in the material. Where ground cork can be obtained at a reasonable price it can be used as the base of purifying material with great advantage over shavings, for the following reasons: It does not become soggy, cake, pulverize or, owing to its spongy nature, become compressed as do other materials, thereby greatly relieving the back pressure thrown by the box; its back pressure is only one-third that of the material ordinarily used. As 50 per cent, more oxide can be mixed with ground cork than with either sawdust or shavings, the capacity of the box is increased 50 per cent. Cork can be obtained as the waste from cork factories, and although the initial cost is invariably greater than sawdust or shavings, it is sometimes offset by its other qualities. Ground corn-cobs are also in use as a substitute for cork, and it is claimed for them that they possess nearly if not all of the qualifications possessed by cork. Their cheapness is a great recom- mendation in their favor. The following table gives the weights of one bushel (2150 cubic inches) of different purifying materials: Material. Lbs. per Bushel. Pine shavings 5 . 25 Ground cork 6 . Pine sawdust 12 . 75 Ground corn-cobs 15. Iron oxide. : 112 . There is authority for the statement that 1.5 per cent, of air admitted to the purify ing -boxes with the gas will add 25 per cent, to the purifying capacity. Preparing Lime. Baker's Masonry Construction gives the fol- lowing characteristics for good mortar. Lime: 1. Freedom from cinders and clinkers, with not more than 10 per cent, of other im- PURIFIERS. 79 purities, as silica, alumina, etc. 2. Chiefly in hard lumps with but little dust. 3. Slakes readily in water, forming a very fine, smooth paste without any residue. 4. Dissolves in soft water when this is added in sufficient quantities. These simple tests can be readily applied to any sample of lime. Common lime is a substance resulting from the calcination of pure, or nearly pure, limestones, such as marble or chalk at a high temperature, applied for a certain time to drive off the CO 2 in the limestone. It principally has calcic oxide with 3 to 10 per cent, of impurities, silica and alumina, magnesia, oxide of manganese, and trace of alkalies. It is highly caustic, with a strong affinity for water, rapidly absorbing about one-fourth of its own weight, which absorption increases its temperature to an intense heat, together with an increase of bulk of from two to three times the original volume. This reduction to an impalpable powder is called " slaked lime" or "calcic hydrate," which forms with water an unctuous paste. This paste, in common with mortar, will not harden in the presence of water. The advantage of using lime for purification, either alone or in combination with iron oxide, is the more complete removal from the gas of sulphur compounds and also the removal of carbonic acid, for which the oxide alone has no affinity (see table of Effect of CO 2 on Candle Power). The effect of CO 2 on illuminating gas can only be removed entirely by purification. Its removal causes a whiter, purer, and brighter light, which cannot be compensated for by increased enrichment or the addition of hydrocarbons. These advantages may be worth the additional cost in purification, even where lime is comparatively dear. It is, however, claimed by advocates of iron oxide that Amer- ican coal-gas contains but few sulphurous compounds other than sulphureted hydrogen, and that this latter is the only needful impurity to remove, and can be accomplished entirely by the use of oxide. It is also claimed that while lime removes the CO 2 it also mechanically separates from the gas certain of the heavier hydrocarbons, thereby neutralizing the benefit derived by its removal. The question reduces itself largely to a basis of cost of materials and as to whether additional oil be used to make up the loss, or whether a saving can be effected by the removal of the CO 2 , thereby increasing the efficiency of a less amount of enrichment used. Calculations. As to the purifying capacity of lime for CO 2 , the theory is as follows: Assuming a bushel of unslaked lime to weigh 80 Ibs. and to contain 90 per cent, of CaO, one bushel of lime would therefore contain about 72 Ibs. of pure CaO, Slaking this lime the following reaction would take place; 80 AMERICAN GAS-ENGINEERING PRACTICE CaO + H 2 O=Ca(OH) 2 , or calcic hydrate. Since the atomic weight of Ca is 40, O is 16, H being 1, the equation would represent (40 + 16) + (2+ 16) = (40 + 17X2) = 74. Therefore, 56 Ibs. of CaO will make 74 Ibs. of Ca(OH) 2 , and 72 Ibs. of CaO will make 95.11 Ibs. of Ca(OH) 2 . The reaction equation between slaked lime and CO 2 is Ca(OH) 2 + CO 2 = CaCO 3 + H 2 O 74 + 44 = 100 + 18 We see that 74 Ibs. of Ca(OH) 2 will combine with 44 Ibs. of CO 2 , therefore 95.11 Ibs. of Ca(OH) 2 will combine with 56.55 Ibs. of CO 2 . Dry CO 2 at 60 F. and 30 in. barometer weighs 1 Ib. for each 8.595 cubic feet, so that 56.55X8.595 = 486.047 cubic feet. Supposing gas to contain 3 per cent, of C0 2 or 30 cubic feet per 1000 cubic feet of the gas, we have 486.047 divided by 30, or 16.202 cubic feet multiplied by 1000, equaling 16,202 cubic feet, the maximum amount of gas with which the calcic oxide in one bushel of lime, as aforesaid, will theoretically combine. Of course, under working conditions, this combination would be exceedingly less complete. On the other hand, the maximum amount of sulphureted hydrogen which can be removed from gas (theoretically) can be calculated as follows: Suppose a bushel of the purifying material to contain an amount of Fe 2 O 3 .H 2 O equivalent to a weight of 25 Ibs. of iron, and assuming that there is no oxygen present in the gas, the proportions would be as follows: Of the Fe 2 O 3 .H 2 O the atomic weights are Fe = 56, O=16, andH=l. The molecule of the oxide will therefore contain (56X2) + (16X3) + (1X2) + 16 = 178 parts by weight, of which 112 parts are iron and therefore 25 Ibs. of iron will form 25X|if =39.7 Ibs. of ferric hydrate. The reaction given by Butterfield for the removal of H 2 S from gas by this ferric hydrate is as follows: Fe 2 O 3 .H 2 O + 3H 2 S = 2FeS + S + 4H 2 0. The proportion between Fe 2 O 3 .H 2 O and H 2 S is the same in both equations; the amount of H 2 S absorbed by a given quantity of Fe 2 O 3 .H 2 O is the same, no matter which of the two above reactions may occur. The atomic weight of S is 32; therefore, the weight of H being PURIFIERS. 81 one, the molecule H 2 SX3, as in the equation, equals 3 (2X1 + 32), or 102 parts. Therefore, 178 atomic parts of Fe 2 O 3 .H 2 O will combine with 102 parts of H 2 S, or 1 Ib. will combine with 0.573 Ibs., from which we derive that 39.7 Ibs. of Fe 2 O 3 .H 2 O will combine with 22.748 Ibs. of H 2 S. Now, if 1 Ib. of dry H 2 S at 60 F. and 30 in. barometer occupied a volume of 11.1229 cubic feet, we con- clude that 22.748 Ibs. will correspond with 22.748X11.1229, or 253.02 cubic feet of H 2 ST Assuming a gas, therefore, to contain 0.85 per cent, by volume of H 2 S it will contain 8.5 cubic feet of H 2 S per 1000 cubic feet of gas, or 253.02-^8.5 equals 29.791, denoting that 29.791 cubic feet is the maximum amount of gas containing the said amount of H 2 S that can be theoretically removed by chemical union with one bushel of the above-mentioned purifying material. But, as noted in the calculations for the theoretical purifying power of lime, these results cannot be nearly attained under working conditions. Temperature. It may be noted, however, that conditions of temperature have much to do with the combining power of both the lime and the oxide, as at a temperature below 30 F. both lime and ferric oxide are practically inactive with reference to H 2 S, and abjve this temperature their capacities for com- bination increase more and more, until at a temperature of 100 to 120 F. the action becomes as complete as can be obtained under working conditions. It follows from this that purifying- houses, lime-rooms, and revivifying-sheds should always be main- tained at a temperature not less than 60 F., and that concrete boxes built out of doors and other exposed purifiers should be properly heated with steam-coil, or the gas itself should be heated prior to entry therein. Testing Oxide Boxes. For determining whether the bed of oxide is doing service or not, Fig. 16, on the following page, illus- trates an easy method. Byron E. Choller describes the arrange- ment thus: "It frequently happens that both inlet and outlet of a purifying-bed will show an equally foul test with lead paper, while the bed may yet be doing work. The cut shows how this condition may be ascertained: a pipe and stop-cock leading from each side of the bed, rubber tubes with glass nozzles of equal size attached, and a weak solution of permanganate of potash are all that are required. Put equal quantities of equal strength of the solution in the test-tubes, insert the glass tubes, and turn on the gas in both at the same time. Foul gas will make the solution clear almost immediately. If the bed is doing work, the inlet side will clear up quicker than the outlet side. Two or three grains, or perhaps less, of permanganate of potash to a quart of clean 82 AMERICAN GAS-ENGINEERING PRACTICE. water is sufficient. Keep the solution in a well-stoppered bottle, and do not make up too much at a time." Judging from a few experiments, when it takes the outlet four or five times as long as it does the inlet to clear up by this method it is time to change the box, as in such case it would be taking out only about 20 per cent, of the sulphur in the gas. SULPHUR TEST TI/5E, FIG. 16. Comparison of Sulphur in Inlet and Outlet Gas. Revivification. This can be done while the gas is passing through the boxes for purification by admitting a small percent- age of air or oxygen, ij per cent, to 0.5 per cent., with the gas; or air can be blown or sucked through the foul oxide after the box is turned off and opened; otherwise the oxide can be re- moved from the box and revivified elsewhere. By revivification is meant the reduction of the iron-sulphur compounds again to active iron oxides or hydroxides; reactions are 2Fe 2 S 3 + 3O 2 - 2Fe 2 O 3 + 3S 2 or 12FeS +9O 2 +6Fe 2 O 3 +6S 2 . PURIFIERS. 83 Oxide can generally be used until it has taken up 60 per cent, of sulphur by weight, although it generally becomes fouled by tar, etc. , before this point is reached. As to the proper handling of oxide for revivification, the Trustees of the American Gaslight Association have to say as follows: "As probably no two samples of iron oxide (the words being used to denote a purifying material in which the active agent is hydrated ferric oxide) are exactly alike, it is impossible to lay down hard-and-fast rules that will apply in all cases. But there is one truth that must always be borne in mind and acted upon to secure the best results; this is, that revivification will be the more rapid and complete the higher (within reasonable limits) the temperature of the oxide. Therefore, the treatment should be such as to retain, as far as possible, in the material all the heat generated by the chemical action that occurs, pro- vided, of course, that this heat is not excessive. "At a works using oxide purchased from three different firms, the following method of handling during revivification was found to give the best results: As the oxide was removed from the box it was thrown on to the re vivify ing -floor, beneath the box, into heaps, each about 8 feet high, and allowed to remain in these heaps until it was thoroughly heated, the length of time required for the attainment of this result varying from one to two hours for fresh, active oxide to forty-nine hours or more for that nearly spent, or sluggish from any other causes. When hot it was taken from the heap and placed on the floor in long ridges, whose cross- section was approximately an equilateral triangle with 24-inch sides. Spaces were left between the ridges, and as the oxide on the two exposed faces revivified, as shown by its change in color, it was scraped down into these spaces until the whole batch was spread out in a layer, with a uniform depth of about 9 to 10 in. It was then turned over with shovels, care being taken to have it really turned and the material that had been on the bottom placed on top, instead of the whole mass being merely shoveled to one side, which is very often all that the so-called turning over amounts to. By this time it was usually thoroughly revivified. If not, it was again turned over as often as necessary. When revivified the batch was piled in a heap about 6 feet high and 4 to 6 feet wide to remain until it was put back into the box in due course. Sufficient time was allowed to elapse between each handling for complete revivification of the top layer of oxide. During the operation the oxide was then wet, unless it became excessively heated or so dry that there was a loss and a nuisance in handling, owing to the dust arising from it. By thus keeping 84 AMERICAN GAS-ENGINEERING PRACTICE. the oxide as dry as possible, all the heat produced by chemical action was made available for maintaining the temperature of the material and thus promoting complete revivification, instead of being used up in vaporizing added water. "In handling batches of fresh oxide care must be taken to prevent their becoming so highly heated as to ignite the sulphur and shavings contained in them. Even in such cases, however, it is better to allow the oxide to stay in heaps. Since less surface is exposed to thp air in this way, the liability of ignition is less, and if it does occur the fire can be more readily extinguished by the use of water. Such heaps should be examined at frequent intervals and any tendency to fire be attended to. Ignition can- not occur with wet oxide until the water has been practically all evaporated, so wetting the oxide will always prevent it. But as it also retards revivification it should only be resorted to in cases of necessity. Spreading the oxide out in layers and turn- ing it constantly will also cool it. "If a batch of oxide does not heat and revivify properly when handled as above, and its record shows that it is not yet saturated with sulphur, it can sometimes be brought into good condition again by being exposed out of doors in the sun during the warm weather, the sun imparting the heat necessary to start and main- tain the revivification; or the batch can be heated artificially. "Another method of revivification consists in placing the oxide, when taken from the heaps, on a platform of purifier-trays, supported about a foot above the floor of the revivifying-room in such a way as to permit a free circulation of air underneath the whole bed, the oxide being spread in a layer 24 to 30 inches deep. When using such a platform revivification takes place on the bottom as well as at the top of the layer, proceeding faster on the bottom. When the batch is turned, the oxide, still foul, should be put on the trays, and the oxide that has revivified either piled to one side or placed on top of the foul oxide. If this method is used with active oxide great care will be necessary to prevent firing, as revivification proceeds very rapidly, owing to the fact that ah* passes up through the oxide instead of merely being in contact with it." It is generally the custom in slaking lime at works to reduce the lime to a sort of paste which will neither adhere to the fingers when suspended from them nor yet fall in a granular powder. It is probable, however, that this is hardly sufficient moisture, and it is better to add enough water to bring the lime to a homo- geneous mass. This mass should be allowed to lie over some hours and then be worked over to rid it from lumps. The tendency of all gas-engineering points toward revivifi- PURIFIERS. 85 cation in situ. This can be best accomplished by the admission of air in a fixed ratio (under 3 per cent.) with the gas at the inlet of the purifiers, which is easily arranged by belting a forge-blower FIG. 17. Revivifying in situ. or one of the Connelly compressors direct to the shaft of the exhauster (Fig. 17). LOSS BY IN SITU PURIFICATION. Air Admitted, Loss in Candle Power, Per Cent. Per Cent. 1.0 2.0 1.2 2.3 1.4 2.6 1.6 3.0 1.9 3.6 2.1 3.9 2.3 4.3 2.5 4.8 Removal of Traces. It must be noticed in all forms of purification that the elimination of impurities, being chemical, can occur only where there is an intimate union and thorough contact of the gas with the material used. Should any tar or oily matter be allowed to come in contact with the purifying material, it will form a coating or insulation which will tend to prevent chemical action from taking place, besides fouling the material and causing it to solidify and coke, thereby producing back pressure. It is of enormous advantage to remove such substances as completely as possible before bringing them in contact with the purifying material, to which end the gas should first be passed through a bed of shavings or coke-breeze (oak- wood shavings should never be used for any purifying purpose, because of the tannic acid contained), forming a filter, which 86 AMERICAN GAS-ENGINEERING PRACTICE. material should be changed immediately as soon as it becomes saturated. In extreme cases a P. & A. condenser may be used or some device of baffle-plates, in which the tar and oil molecules carried along in suspension impinge and drain away by gravity. Some such device will be found a great economy in works, as it has been the experience of the writer from a number of tests that the oxide or lime in the first boxes of the purifying series almost invariably become so foul as to become useless long before its combining affinity has ceased, and that by the use of proper extractors or filters the life of these materials will be indefinitely prolonged. In addition to the injury done purifying material by small portions of heavy tar and oil, carried over in suspense by the gas, and for which there should be mechanical separation, tarry vapors are likewise a great menace not only to the material itself, but to the subsequent features of distribution, such as mains, services, the drums of meters, the cocks of fixtures, and espe- cially the tips of burners and Welsbach mantles and appliances. The simplest method of breaking up these vapors consists in placing a layer of chips and shavings or coke-breeze on the lowest tier of the trays of each purifying-box, so that when a box becomes the first in the series the gas passes through this filter, and the vapors are filtered out before the material in the upper portion of the box is reached. It is, however, better, where possible, to have one box or other vessel retained solely for the use of such scrubbing and containing several thick layers of wood chips, sawdust, and shavings or breeze. This box should invariably be the first in the purifying series, and this arrangement has the advantage that it can be easily determined as to the time when complete satura- tion of its material takes place, after which time it very imper- fectly filters out the passing vapors. A discussion of the subject will be found in the Proceedings of the American Gaslight Asso- ciation, Vol. 15, pp. 142 to 147, and can be read to some advantage. A gas is said to be saturated with vapor at a certain tempera- ture and pressure when it contains the full amount of vapor that it can carry under these conditions. Any change in these condi- tions will change its point of saturation, thereby causing it to carry more or less vapor or moisture. Also, when a gas is so saturated it cannot be made to take up any more vapor unless these condi- tions be altered. At any given temperature and pressure a definite quantity of a given vapor is required to saturate a gas, and this quantity is invariably the same under the same conditions. This is called the saturation- or dew-point. Analysis for Total Sulphur. The following excellent system was described before the American Gaslight Association by W. B. PURIFIERS. 87 Calkins of St. Louis, Mo.: The method depends upon the well- known chemical fact that sulphur compounds, such as carbon bisulphide, mercaptan, and other organic forms, break up and form H 2 S when mixed with free hydrogen and passed over heated platinized asbestos or pumice. After the sulphur compounds have been changed to the form of H 2 S, it is a very simple matter to precipitate the sulphur in some form easily weighed or titrated, and the per cent, of sulphur figured back as grains of total sulphur per 100 cubic feet of gas. In order to have the analysis as rapid as possible, gravimetric methods were not considered, but the well-known titration method with a standard iodine solution was used. The iodine method used is one commonly employed for rapid determination of sulphur in pig iron and steel, and consists in absorbing or precipitating the sulphur evolved from the iron or steel as H 2 S in solutions of NaOH, KOH, or in an ammoniacal solution of cadmium or zinc chloride. The use of the two latter are to be preferred on account of the sulphur being in a visible form (CdS or ZnS), and one which is not liable to alteration on standing. The reaction that takes place when H 2 S is run into a strongly ammoniacal solution of cadmium chloride is as follows : H 2 S + CdCl 2 + 2NH 4 OH = CdS + 2NH 4 C1 + 2H 2 0. Now if the solution containing the precipitate of CdS is diluted with a large volume of cold, distilled water and a sufficient quantity of HC1 added, H 2 S is set free by the following reactions: A considerable excess of HC1 is needed to effect a complete reaction, and the volume of water present must be large and cold in order to prevent the escape of any H 2 S. The solution of H 2 S in water is now titrated with a standard iodine solution, using a little fresh starch solution as an indicator; the reaction is as follows: H 2 S + 2I = 2HI+S. The least excess of iodine is shown by the intense blue color (iodide of starch) that is instantly formed as soon as the reaction is complete. The solutions needed are a standard solution of iodine, a fresh, clear solution of starch, and a strongly ammoniacal solution of cadmium or zinc chloride. 88 AMERICAN GAS-ENGINEERING PRACTICE. No arbitrary standard solution of iodine is needed, but one can be made up and standardized to suit local conditions, the prepara- tion and standardizing of which can be found fully explained in any good book on quantitative analysis. For the cadmium chloride solution a good strength for the stock bottle is made by dissolving four grains of cadmium chloride in 100 c.c. of water, and when dissolved add an equal volume of strong, chemically pure ammonia. The platinized asbestos for filling the combustion-tube is easily prepared: Take J pound of clean asbestos wool, free from sulphur, wash in 2 ounces of a 5 per cent, solution of platinum chloride, then dry, place in a large evaporating, dish, separate the wool, moisten evenly with alcohol and ignite ;Ythis forms a coating of platinum black over the wool fibers. The wool must now be strongly heated in order to drive off any free acid. The apparatus needed for this method consists in a good meter, on 3 that will accurately measure -^ of a cubic foot (or, in place of this, a good meter-prover can be used, and the sample of gas it contains can be taken as representing the average gas made for several hours); a small 15-burner combustion furnace; some good Jena glass combustion-tubing 30 in. long, or a flanged porcelain tube glazed inside, 30 in. long and J in. inside diameter; about four plain, ringed-neck glass cylinders 9 in. high, to hold about 150 c.c. , with 2-holed rubber stoppers to fit; one small brass aspira- tor^ filter-pump, and several feet of good glass and pure gum rubber tubing for making connections. FIG. 18. Analysis for Total Sulphur Apparatus. Before starting the test the meter and combustion-tube must be filled full of the gas to be tested and the gas shut off, then the combustion furnace heated up, slowly at first so as not to crack the combustion-tube, until the tube is a dull red (about 1000 to 1200) ; now read the meter, turn on the gas, and by means of the aspirating-pump draw the gas through the loosely packed combus- tion-tube, which is connected to a delivery-tube which reaches almost to the bottom of the first receiving cylinder, then through a second receiving cylinder and out through the aspirating-pump, PURIFIERS. 89 which is attached to the water service. By means of the pump the gas can 'be drawn at any required speed through the apparatus, but faster than J foot an hour is liable to bubble the cadmium chloride solution out of the first cylinder into the second. The second cylinder is used as a guard in case any H 2 S might pass the first one. Both cylinders are filled with a solution of the same strength; 3 c.c. of the strong cadmium solution is first added to each cylinder, then about 10 c.c. of strong ammonia, after which the cylinders are filled with distilled water to a depth of about 7 in. When the required volume of gas has been passed, the meter and aspirating-pump are shut off, the cylinders disconnected and washed out with a large volume of cold water into a deep cylin- drical beaker, a few cubic centimeters of starch solution are added, and then a large excess of concentrated chemically pure HC1, and, without much stirring at first, the whole titrated with the iodine solution as rapidly as possible, adding it until the last drop changes the opalescent liquid to a deep blue, not disappearing on standing for two or three minutes. There must be no delay in titrating, for if the solution contain- ing the CdS is allowed to stand it will lose [28, or the sulphide may oxidize. Another method is to quickly filter off the flocculent precipi- tated CdS, the filter and precipitate placed in a deep beaker con- taining a large volume of cold water, the HC1 and starch solu- tions added, then titrating. This avoids the presence of a large amount of ammonia salts and any hydrocarbons absorbed in the liquid with which it has been claimed the iodine reacts slightly. The combustion-tube must be loosely packed from time to time with fresh platinized asbestos, for the old will gradually be coated with carbon and the tube stopped up. To prove that the chemical reaction was complete, known quantities of chemically pure carbon bisulphide and mercaptan were vaporized with pure hydrogen gas. This mixture was passed through the apparatus, the H^S precipitated with cadmium chloride, and the amount of sulphur found agreed with the per cent, of sulphur contained in the organic sulphur compounds. Other tests for accuracy were made by comparing results obtained from the same sample of gas, by determining the per cent, of total sulphur present, first with the London Gas Referees' sulphur apparatus, then by the combustion method, and the results agree very closely. The following are a few of the results : 90 AMERICAN GAS-ENGINEERING PRACTICE. SULPHUR IN GAS PER ONE HUNDRED CUBIC FEET. Referees' Combustion Method. Method. 1 14.512 14.530 2 16.224 16.320 3 15.820 15.980 4 18.256 18.724 f Correction for temperature and pressure must be made as in any gas analysis. ...-,.,... ^-. v SecT,eN CO B PURIFIERS. 91 n t a, E FIG. 20. The accompanying cuts. A, B, C, D (Figs. 19 and 20), show the arrangement of a Purifying-box equipped with the Jaeger Grid, while cut E shows a section of the Grid itself. AS will be seen the object of the Grid is to increase the inti- macy of the circulation, and obtain for the box higher cubical capacity and greater oxide efficiency. CHAPTER VIII. EXHAUSTERS. THE trustees of the American Gaslight Association give the following calculation for obtaining the horse-power necessary to handle a given quantity of gas, pumping it with an exhauster. As an example of their calculation, they take the pumping of 17,000 cubic feet of gas per hour, with an inlet pressure of 1.1 in. against an outlet pressure or head of 12 in. " Power Required. The term horse-power is used to indicate the rate at which mechanical work is done and denotes the per- formance of 33,000 foot-pounds of work per minute; that is, the raising of a weight of 33,000 pounds through a height of one foot, or the overcoming of a resistance of 33,000 pounds through a space of one foot. The horse-power required to pump gas can therefore be calculated by dividing the product of the resistance overcome and the space through which it is overcome in a minute by 33,000, the resistance being measured in pounds pressure and the space in feet. The resistance is determined by the net pres- sure against which the exhauster is working, that is, by the differ- ence between the pressure at the outlet and that at the inlet of the exhauster. The space can be taken as the number of cubic feet of gas pumped in a minute, without any reference to the actual velocity with which the gas passes through the outlet-pipe, since with a given outlet pressure the total resistance against which the exhauster is working varies directly as the area of the out- let-pipe, while the velocity of the gas, or the space passed through in the unit of time, varies (when the same quantity is pumped per minute) inversely as the area of the outlet-pipe, and there- fore the product of the total resistance and the space passed through will always be equal to the product obtained by mul- tiplying the resistance per square foot by the number of cubic feet of gas pumped in the unit of time. The gas pressure is usu- ally given in terms of the height in inches of the water column which it will balance; to convert this to pounds per square foot, 92 EXHAUSTERS. 93 it is necessary to multiply it by the weight- of a column 01 water 1 sq. ft. in area and 1 in. high. A cubic foot of water weighs 62.5 pounds; therefore a column of water 12 in. high exerts a pressure of 62.5 pounds per sq. ft., and a column 1 in. high will exert a pressure 62.5 -=-12 =5. 2 pounds per sq. ft. The horse- power required for the actual work of pumping the gas can there- fore be determined by multiplying the number of cubic feet pumped per minute by the product obtained by multiplying the net pressure in inches of water by 5.2 (which gives the pressure in pounds per square foot against which the exhauster is work- ing) and dividing the final product by 33,000. Putting this rule into the shape of a formula, we have 33,000 ' in which V= number of cubic feet of gas pumped per minute, and H = thQ difference between the outlet and the inlet pres- sure in inches of water. In the present problem 17.000 - -^- = 283.33 cu. ft., and # = 12-0.1 = 11.9 in., 283.33X11.9X5.2 33,UUU 17532.46 33,000 -0.531 h.p. " Therefore the horse-power required for pumping the gas, without taking into consideration the friction of the exhauster or any other losses of power in the machinery, is 0.558 h.p. " George J. Roberts, from actual tests on pumping gas into a holder, deduced the following formula for an exhauster of the \Vilbraham type: H.P. =0.00511#7; H = the net pressure in inches pumped against, and V= thousands of cubic feet pumped per hour. " Substituting the value of H and V in the present problem, we have H.P.=0.00511X11.9X17 = 1.03. 94 AMERICAN GAS-ENGINEERING PRACTICE. " So that the total horse-power required according to this for- mula is nearly double that required for pumping the gas." Or, in other words, the efficiency of the engine and exhauster when working at this rate is only about 50 per cent. Installation. In installing the exhauster, solid masonry should invariably be used, no other material being as good for a founda- tion. The bed-plate is bolted directly by bed-bolts to this, and without any intervening wooden structure, which may have a tendency to decay and increase vibration. One of the most common causes of trouble is due to the springing of the outlet and inlet connections into place to correct the fitting, the latter not being true. This tension has a tendency toward causing knock- ing and binding of the working parts of the machine. The con- nections should invariably be square and true, and so supported as to relieve the flanges of the exhauster not only of any torsion, but of their own weight. Internal heating, which is difficult to discover, occasioned by the thrust of the crank-shaft of the engine, is another contin- gency with exhausters. This is frequently caused by the set of the machine not being perfectly level and can usually be de- tected and the cause located by taking out the bolts of the coup- ling, an imperfect alignment being indicated by the springing of the coupling flanges. Misalignment of the parts of the bed- plate is indicated by a separation of these parts, while a thrust of the crank-shaft is shown by the binding of the flanges against each other. This can be remedied by forcing the engine to or from the exhauster, re-reaming the dowel-holes and driving in fresh dowels. Operation. It sometimes happens, after an exhauster is shut down, that it is " tar-bound." This is overcome by the intro- duction of benzine or kerosene through the sight-feed oilers, placed at the top of the exhauster case. An exhauster should be as carefully kept up as any other form of a steam-engine. The first and most important point is that of cleanliness, which cannot be overrated, all excess of tar, oil, and dirt being kept away from the governor and other working parts. The adjustments should be examined daily, and once or twice a season an indicator diagram should be taken from the engine, to note if valves are properly set. The machine should have constant attention with regard to oiling, and the engineer should by regular inspection note that the oil-cups are replenished and are emptying equally. The packing of ex- hausters is especially prone to become hard and to grind the axle-shafts and other working parts. It should be removed as often as inspection shows to be necessary, perhaps once in three EXHAUSTERS. 95 months. It is needless to say that all bearings must be prop- erly kept up, especially those supporting the impellers. The gears may best be lubricated with a mixture of grease of good quality or graphite. Losses. The power lost in friction in an exhauster will aver- age between 7 and 9 per cent, of the total amount applied to the machine during the period of full load. It is, however, very nearly constant and varies but slightly between the maximum and minimum load. The slip is also a constant quantity under any one pressure, the total slip per minute being about the same, whether the machine is running fast or slow. In a com- parative test, where the air delivered was measured by meter, and in what is known as the " closed discharge test," the results disclosed little or no discrepancy. The " closed discharge test " is apparently the more accurate, and consists in closing the valve on the discharge side of the machine, when the machine is then operated at such speed as to maintain the pressure desired. The slip is then equal to the displacement of the machine per revolution, multiplied by the number of revolutions per minute, to maintain the pressure. It is, of course, understood that the valves in the connection should be perfectly tight. As to thermal loss, there is but little known. Air compressed to three pounds, according to the test of Geo. C. Hicks, Jr., shows an increase in temperature of 18 deg. F. The specific heat at constant pressure is about 0.2377; hence it will appear that the loss would be extremely small in actual units of work. For in- stance, the maximum loss, due to the difference between iso- thermal and adiabatic compression in air compressed to five pounds, is only about 4.5 per cent. In the case of the rotary machine, at least, the compression is adiabatic or very nearly so. Where the steam-piping is small, or the steam pressure vari- able, it is advisable to interpose a regulating-valve immediately before the steam-inlet of the exhauster. In the use of any positive-pressure gas-pump (especially where there is no holder on the line) and in the connections of an ex- hauster, a relief-valve or seal-pot should be placed upon the pressure side, its overflow or " escape" being connected to a blow-back or by-pass, leading into one of the holders or the suction side of the pump or exhauster. In the first case this is to prevent excessive " building up" of pressure in the pipe-line; in the case of the latter, or exhauster, the arrangement is to prevent the "blowing" of the purifying- boxes; in this instance the relief -valve or seal for blow-back must be adjusted considerably under the seal capacity of the boxes, securing thereby a margin of safety. 96 AMERICAN GAS-ENGINEERING PRACTICE. Few engineers are aware of the loss, amounting to a material item, occurring through the blowing of the boxes and the conse- quent escape and loss of gas, to say nothing of the tremendous danger to life and property. Slip. According to Mr. Geo. C. Hicks, Jr., "the slip of a ro- tary blower should vary as the square root of the pressure, speed being constant, and inversely as the speed, the pressure being constant; directly as the clearance; directly as the square root of the reciprocal of the specific gravity, and directly as the square root of the ratio of the absolute temperatures." For continuous-contact impellers the law of flow of gas through an orifice is very close to actual results. It will, therefore, appear that to at- tain high efficiency in a machine it should be as nearly as possible of such size as will warrant approximately its maximum rate of speed during service. For the increase of volume of gas passed in a given time decreases the per cent, of slip in inverse ratio as the increase of revolutions per min- FIG 21 - Exhauster By-pass ut ?' Thi f !? ? enerall y true U P to the and Connections. safe speed limit. The slip also varies directly as the square inches of the opening of clearance, which should therefore be kept down to the lowest margin compatible with safety. This is especially true with heavy-duty exhausters (operating over 3 to 4 Ibs. pressure). In low-pressure work the slip may be said to vary, inversely with the speed, from 1 to 20 per cent. Temperature affects the slip only, as has been stated, as proportional to the square root of the ratio of absolute temperature, and has nothing to do with the shrinkage in volume due to a decrease in gas temperature. Specific gravity affects the slip, as above stated, as the square root of the reciprocal, as, for instance, gas at 0.5 gravity would give a slip 1.41 times as much as air under similar conditions. The friction losses in an exhauster are practically those en- tailed by the bearings and the gears. The pressure of the gears should be plus in a downward direc- tion, in order to prevent a "floating shaft," as such an arrange- ment is hard to keep in alignment and tends toward hot bearings. EXHAUSTERS. 97 In this connection we may say that much depends upon the accuracy of cutting and keying of the impeller-gears, the juxta- position of the impellers, the conditions of clearance, and the general alignment subject to such accuracy. For low-pressure machines (1 to 2 Ibs.) single gears with double outboard bearings are preferable, while with the heavy-duty machines double gears with outboard bearings give better satisfaction. The advantage of the outboard bearing is to distribute the strain upon the machine and furnish double- instead of single-bearing surface, besides stiffening the entire apparatus. Horizontal machines are, moreover, stiffer and better adapted to heavy duty than the vertical type. The double outboard bearings mentioned should be invariably specified, their cases in the instance of high pressures being approximately 2.25 times the gear diameter in length, and a bore, say, 1.65 times the gear diameter; for light duty (say 1 or 2 Ibs.) 1.5 times the gear diameter will be sufficient. The driving of exhausters belongs to three classes, viz., belt or rope drive, pinion gear and silent chain, and " direct connec- tion." For the first the belt pull should average about 75 Ibs. and have a speed of between 3000 and 4000 feet per minute. At this figure the loss of power should not exceed over 3 per cent. Counterbelting should be permitted only on very light service loads. For this class of drive outboard bearings are especially ne3essary to maintain rigidity. The silent chain should give an efficiency of about 98 per cent., gear transmission 95 per cent. These methods are especially necessary in connection with turbine or high-speed motive power. Where direct connection is used the flexible connection is decidedly advisable, and is absolutely essential in heavy-duty machines having the service of over 4 Ibs. This is by reason of the facility with which alignment between the exhauster and prime mover may be maintained, this being almost impossible where the connection is rigid. Of late years small exhausters have come into frequent use in connection with " booster" or high-pressure feed-lines, also for long-distance transmission. Such service rarely exceeds a maximum of over 4 Ibs. dis- charge duty with 8 to 12 inches water pressure on the suction end. Under such conditions the total losses (principally slip and friction) will hardly exceed a maximum of 15 per cent., 7 or 8 per cent, being the average. As this service must be executed under variable conditions of speed, the prime mover should be designed for very sympathetic hand regulation. The highest efficiency of this service is at about 5 Ibs. duty, where the minimum efficiency is possibly not below 80 per cent. 98 AMERICAN GAS-ENGINEERING PRACTICE. For heavier duty, however, say 8 to 10 Ibs. or over, its commer- cial efficiency ceases, and some other form of condenser or pump should be used. In emergency, however, for service of this kind two or more exhausters may be connected in tandem with a fair degree of efficiency. In summing up the losses due to slip, Mr. Geo. C. Hicks, Jr., an expert in the matter, says : " Losses due to slip are dependent on two principal factors, pressure and speed. The curves shown for constant speed and varying pressure cover a range of pressure from 22 in. of water to 122.1 and a loss due to slip within the ranges of ordinary opera- tion of from 30 per cent, maximum to 1 per cent, minimum. "In gas-exhauster work, say at a maximum pressure of 22.5 in. of water, the slip ranges from 1 per cent, for various speeds on an air basis. Modifying this for gas by multiplying by the square root of the reciprocal of the specific gravity or 1.41, the resultant loss is from 1.41 per cent, to 28 per cent., or an average slip of 14.75 per cent, for speeds ranging from 50 to 170 r.p.m. " For pumping clean gas, where it is possible to use a nearly constant speed, it is clearly advisable to select a machine to oper- ate at its highest safe speed and thus get an efficiency of 81 per cent, according to these tests, which were made on a machine not specially built for this service. Later results show an effi- ciency of 85 per cent, under 5 Ibs. pressure. The loss due to friction ranges from 1 to 15.5 per cent, and shows an aver- age of about 7 per cent, at 130 and 170 r.p.m., and 5.4 per cent, at 110 r.p.m.; so it is safe to assume 7 per cent, as an average friction load. This gives for gas-exhauster work an average efficiency of power applied to the shaft of 85.26 per cent, times 93 per cent., or nearly 80 per cent., as the useful effort of the power applied to the shaft. For high-pressure pumping we have 81 per cent, multiplied by 93 per cent., or 75.3 total, and on a basis of 85 per cent, volumetric efficiency a total efficiency of 80 per cent. The loss due to temperature is not chargeable to the machine construction, as it is simply a shrinkage proposition and brings one to much the same set of formulas as those used in estimating condenser surfaces. Not considering the latent heat of the vapors, an approximate method is to consider the volumes as propor- tional to their absolute temperatures. "The increased slip, as stated before, would be proportional to the square root of the ratio of the absolute temperature. As- suming a rise to 140 deg. from 60 deg., the slip would be multi- plied by the ratio 1.07; this 14 per cent, slip times 1.07 equals about 15 per cent., or an increase of only 1 per cent, due to a rise in temperature of 80 deg. The heat of compression at 10 Ibs. EXHAUSTERS. 99 would raise air at 60 deg. up to 145, affecting the slip about the same amount 1 per cent. The heating effect on the incoming air would be slight and I do not believe would result in an appre- ciable loss in volume delivered. The results stated before in- clude all these losses, and these points are brought up to show there is no need to consider these items as separate losses, at least at the comparatively low pressure used in rotary machines, and as a matter of fact it is probable that, the case expansion being less than the impeller expansion, the clearance is reduced and the slip decreased to some extent, probably enough to offset the additional slip due to the decrease in the density of the gas." Air=compressor Capacity. Capacities of air-compressors in cu. ft. of free air per minute in common practice are Uoually cal- culated by multiplying the area of the intake cylinder by the feet of piston travel per minute. The free air capacity divided by the number of atmospheres will give the volume of compressed air per minute. To ascertain the number of atmospheres at any given pressure, add 14.7 Ibs. to the gage pressure, divide this sum by 14.7, and the result will be the number of atmospheres. This calculation, however, is merely theoretical, and the results derived are never attained in actual practice, even with compres- sors of the very best design. Allowances should be made for vari- ous losses, the principal one being due to clearance spaces, but in machines of poor design and construction considerable losses occur through imperfect cooling, leakages past the piston and through the discharge-valves, insufficient area and improper working of inlet-valves, etc. There are compressors where the total losses run as high as 30 per cent., whereas 2.5 to 10 per cent, should be the maximum. The altitude at which the compressor is to operate is an impor- tant factor, as it affects its capacity in direct ratio to the ele- vation. It will be seen, as the density of the atmosphere de- creases with the altitude, a compressor at hi?h altitude takes in less weight of air at each revolution. The air being taken in at the intake at a lower initial pressure, the earlier part of each stroke is occupied in compressing the air up to the normal pres- sure of 14.7 Ibs., and the net capacity of the air-cylinder is thereby reduced. The power required to drive the same compressor is also less than at sea-level, but this decrease being in lesser ratio is not an offset. Compressors to be used at high altitudes should have the steam- and air-cylinders properly proportioned to meet varying conditions. The first table on page 103, based on a compressor working at sea-level and discharging at a pressure of 70 Ibs., in- dicates the variation of compressors at different altitudes. 100 AMERICAN GAS-ENGINEERING PRACTICE. TABLE OF SIZES, POWER, AND CAPACITIES OF ROOT'S GAS- EXHAUSTERS. No. of Exhauster. Suction and Discharge Diameters. Horse-power at Stated Speed. Speed of Exhauster. Displacement in Cu. Ft. per Revolution. Capacity per Hour in Cu. Ft., No Allowance for Shrinkage. 2 4 .75 200 .72 8,600 3 6 1.5 190 1.50 17,100 4 8 2.5 180 3.07 33,150 5 10 3.75 170 5.20 52,140 6 12 5. 160 8.20 78,720 7 16 7.50 150 12.43 111,840 8 16 11. 140 20. 168,000 8| 20 15.5 130 29. 226,200 9 20 19. 120 37.25 268,200 9i 20 24. 110 50. 330,000 10 24 29. 100 63.10 378,600 10| 30 36. 95 83. 473,100 11 30 50. 90 116. 626,400 12 36 80. 85 196. 999,600 14 42 115. 80 300. 1,444,000 NOTE. Horse-power figured on basis of one pound per square inch, at speeds given in this table. WILBRAHAM-GREEN GAS-EXHAUSTERS. J 1 c"-S I II "pQ ki "c 1 &l |3 u +3 O || .2 i* fe li 0> 22 1! 1* fg 6 V o'S.2 II! I 1 8 ew Jpi .fS %\ I 3 Ss &S fiL 2 s Q tf 5 B H Q Q 3 6 li 100 9,000 216,000 150 13,950 334,800 4 8 3 100 18,000 432,000 150 27,000 648,000 5 10 5i 100 33,000 792,000 150 49,500 1,188,000 6 12 9 100 54,000 1,296,000 130 70,200 1,684,800 7 16 15 90 81,000 1,944,000 125 112,500 2,700,000 8A 16 22 90 118,800 2,851,000 125 165,000 3,960,000 9A 20 35 85 178,500 4,284,000 115 241,500 5,796,000 9s 20 45 75 202,500 4,860,000 110 297,000 7,128,000 9i 24 55 75 247,500 5,940,000 110 363,000 8,712,000 10 24 67 70 281,400 6,753,600 100 402,000 9,648,000 10i 30 85 70 357,000 8,568,000 100 510,000 12,240,000 11 30 112 70 470,400 11,289,600 100 672,000 16,128,000 SB 16 25 Special size The above volumes are the displacement of the exhausters at a moderate speed, without allowing anything for loss or shrinkage. EXHAUSTERS. 101 Is Q OQ Is SB I-HOQO OO-*CO l(N-*O> OOcOrfc (W 1 * T-HT-ICOC '(NO 1CDO> !> t--< 00 O5 CO 00 ^ ^H c lO^ ^CO COCO' O5 WOO >O coco r^-< I^HO 0>< >t-t>- O ^05 )CO"3 iC^Tj<( CO 00 1C OOCO 1C So 102 AMERICAN GAS-ENGINEERING PRACTICE. Z1 I si 85; ^ o O ^ CO I s * Oi*OCM>O f>- 00 *C GO CO CO CO 'O ^ i i CM C 'O CO O CO CM O 00 CO 'l CO <-< O O5 00 t- h- CO CO >O ' ^fCOCOCM CMCN^H^H i-Hi-li-li-l iCMOOCO tMCMt-UJ >00 lO -> CO >O CMO )"*TfTti COCOCOCO OS-HOCO oscoco-* TfcOCMtM w2In2 O OOOC OO CO T t TT (NrH COOS ' CO *O S COCO 1C * OI-H CD iTtiQO * r-iost^- 1C < COCMCM CNi-ii-H I-H os^-ico--i coi 'OOO ^H CO i-H I oor-i>co coi t^ CMOS O O0< 1^ "O CM OS iO { ^ <* -^ co co ( -HCO'-iCO OOCOCO OCO^CO OOCOOt^- CMCMOOb- OCOTt.CO OOOCO"C CO'-iOOS COt-COCO CCiC'* MH r}< TJH CO COCOCMCM Tt^COCMcM CM ^H t i ii T-H T I ? ( 500 qOQOQOiC COOSOO CM CM CO TJH.-HO5CD COO< ^ ^ coco co coi CO CO CN CM 5t-00 CNCO'tfOO CO^CDb- COC3Sb-OS * CM CM h. 00 <** ^H Tf ) >C CO (NOOSCO t-COCOiC C C ^ * * T}H CO CO COCMCMCM CO>CO5CM CMOSt-iO iCi-irHO OlCMt-^H OCOIOO5 OT}CCM OOOCOCO O 00 CO * * O COCO^CO CMOOSOO t>-COCOiC ^^^^ -^COCOCO COCMCMCM 5 CM CM ( )OOiC fcOOCDCO OiCMt^CO JCOCM ^HOiOOt- CDCO'C'C "CCOtM^H OOOt-CO CO CMCOOO t-OOCMO OCMCOOO iC'COOrt* COOOOCD ^fCMOr- "CcOiO ^^COCO CO CO CO CM CMCMCMCM JCOOO^H ^HiOCOCO Tfi^nOC JCMOOCO -^CMr-iO O500IX oooo iOCO CO COCOCMCM II- SfS EXHAUSTERS. 103 INFLUENCE OF ALTITUDE ON EFFICIENCY OF COMPRESSORS. Altitude, Feet. Barometric Pressure. Volumetric Effi- ciency of Com- pressors, Per Cent. Sea-level = 100. Loss of Capacity, Per Cent. Decreased Power Required, Per Cent. Inches Mercury. Pounds per Square Inch. 1,000 28.88 14.20 97 3 1.8 2,000 27.80 13.67 93 7 3.5 3,000 26.76 J3.16 90 10 5.2 4,000 25.76 12.67 87 13 6.9 5,000 24.79 12.20 84 16 8.5 6,000 23.86 11.73 81 19 10.1 7,000 22.97 11.30 78 22 11.6 8,000 22.11 10.87 76 24 13.1 9,000 21.29 10.46 73 27 44.6 10,000 20.49 10.07 70 30 16.1 11,000 19.72 9.70 68 32 17.6 12,000 18.98 9.34 65 35 19.1 13,000 18.27 8.98 83 37 20.6 14,000 17.59 8.65 60 40 22.1 15,000 16.93 8.32 58 42 23.5 The National Tube Co. has compiled the following table: HORSE-POWER REQUIRED TO COMPRESS 100 CUBIC FEET FREE AIR FROM ATMOSPHERIC TO VARIOUS PRESSURES. Gage Pressure, Pounds per Sq. In. One-stage Compression, D.H.P. Gage Pressure, Pounds per Sq. In. Two-stage Compression, D.H.P. Four-stage Compression, D.H.P. 10 . 3.60 60 11.70 10.80 15 5.03 80 13.70 12.50 20 6.28 100 15.40 14.20 25 7.42 200 21.20 18.75 30 8.47 300 24.50 21.80 35 9.42 400 27.70 24.00 40 10.30 500 29.75 25.90 45 11.14 600 31.70 27.50 50 11.90 700 33.50 28.90 55 12.67 800 34.90 30.00 60 13.41 900 36.30 31.00 70 14.72 1000 37.80 31.80 80 15.94 1200 39.70 33.30 90 17.06 1600 43.00 35.65 100 18.15 2000 45.50 37.80 2500 39.06 3000 40.15 D.H.P. = delivered horse-power at compressor cylinder. 104 AMERICAN GAS-ENGINEERING PRACTICE. Another table is as follows: HORSE-POWER DEVELOPED IN COMPRESSING ONE CUBIC FOOT OF FREE AIR FROM ATMOSPHERIC PRESSURE (14.7 POUNDS) TO VARIOUS GAGE PRESSURES. Initial Temperature of the Air in Each Cylinder Taken as 60 F. (Jacket Cooling Not Considered.) Gage Pressure. Isothermal Compression. Adiabatic Compression. One Stage. Two Stage. Three Stage. Four Stage. 10 0.0332 0.0358 20 0.0551 0.0623 30 0.0713 0.0842 40 0.0842 0.1026 50 0.0950 0.1187 60 0.1042 0.1331 70 0.1122 0.1465 0.128 0.122 0.119 80 0.1194 0.1585 0.137 0.131 0.127 90 0.1258 0.1695 0.146 0.139 0.135 100 0.1317 0.1800 0.154 0.146 0.142 125 0.1443 0.2036 0.171 0.161 0.157 150 0.1549 0.2244 0.186 0.174 0.169 200 0.1719 0.2600 0.210 0.196 0.190 300 0.1964 0.3164 0.247 0.229 0.220 400 0.2141 0.3613 0.276 0.253 0.242 500 0.2279 0.3889 0.299 0.272 0.260 600 0.2393 0.4318 0.318 0.288 0.275 700 0.2489 0.4608 0.335 0.302 0.289 800 0.2573 0.4873 0.349 0.314 0.299 900 0.2649 0.5114 0.363 0.325 0.310 1000 0.2720 0.5337 0.375 0.335 0.318 1200 0.2820 0.5742 0.397 0.353 0.333 1400 0.2924 0.6102 0.414 0.368 0.347 1600 0.3012 0.6427 0.432 0.381 T).359 1800 0.3087 0.6724 0.447 0.393 0.369 2000 0.3154 0.7003 0.460 0.403 0.379 NOTE. The above values are for sea-level conditions only. The loss in delivery of power in compressed air and gas (approximately) for single-stage compression will average perhaps 30 per cent., while that of two-stage compression will perhaps not exceed 17 per cent., while four-stage compression reduces the transmission loss to about 8 per cent.; as a stand-off against this economy, of course, is the additional initial power necessary to overcome the resistance and friction caused by additional valves, ports, coolers, etc., which may require an increase of from 10 to 15 per cent. There is also a reduction of the unit strain upon the apparatus, all depending largely, however, for its efficiency upon the details EXHAUSTERS. 105 PRESSURE AND VOLUME OF COMPRESSED AIR (SHONE). Pressure above Atmosphere. Comparative Volume of Air after Compression. Initial Volume = 1. Tempera- ture by Adiabatic Compres- sion, that Rate of Com- pression Average Load against Compress- ing Piston, per Square Inch. of the Isother- Free Air mally. Isother- Adia- being 60 Isother- Adia- mally. batically F. mally. batically. Lbs. per Sq. In. Inches of Mercury. Feet of Water. Volume. Volume. Fahr. Com- pression. Load. Load. 2.041 2.31 0.936 0.954 70.04 .0680 0.967 0.976 2 4.082 4.61 0.880 0.913 79.64 .1361 1.876 1.910 3 6.123 6.92 0.831 0.876 88.84 .2041 2.730 2.805 4 8.164 9.23 0.786 0.843 97.68 .2721 3.538 3.664 5 10.205 11.54 0.746 0.812 106.18 .3401 5.303 4.491 6 12.246 13.84 0.710 0.784 114.39 .4081 5.031 5.288 7 14.287 16.15 0.677 0.758 122.32 .4762 5.725 6.060 g 16.328 18.46 0.648 0.735 129.99 .5442 6.387 6.806 9 18.369 20.76 0.620 0.713 137.43 .6122 7.021 7.529 10 20.410 23.07 0.595 0.692 144.65 .6803 7.629 8.232 11 22.451 25.38 0.572 0.673 151.66 .7483 8.212 8.914 12 24.492 27.68 0.551 0.655 158.48 .8164 8.774 9.578 13 26.533 29.99 0.531 0.638 165.13 .8844 9.315 10.224 14 28.574 32.30 0.512 0.622 171.60 .9524 9.836 10.854 15 30.615 34.61 0.495 0.607 177.92 2.0204 10.338 11.468 16 32.656 36.91 0.479 0.593 184.09 2.0884 10.825 12.068 17 34.697 39.22 0.464 0.579 190.11 2.1565 11.297 12.654 18 36.738 41.53 0.450 0.567 196.01 2.2245 11.753 13.227 19 38.779 43.83 0.436 0.555 201.77 2.2925 12.193 13.788 20 40.820 46.14 0.424 0.544 207.42 2.3605 12.623 14.337 21 42.861 48.45 0.412 0.533 212.95 2.4286 13.044 14.875 22 44 . 902 50.75 0.401 0.522 218.37 2.4966 13.450 15.403 23 46 . 943 53.06 0.390 0.512 223 . 69 2 . 5646 13.844 15.921 24 48.984 55.37 0.380 0.503 228.91 2.6327 14.230 16.429 25 51.025 57.68 0.370 0.494 234.03 2.7007 14.604 16.927 26 53.066 59.98 0.361 0.485 239.07 2.7687 14.970 17.419 27 55.107 62.29 0.353 0.477 244.02 2.8367 15.327 17.898 28 57.148 64.60 0.344 0.469 248.88 2.9048 15.676 18.371 29 59.189 66.90 0.336 0.461 253.66 2.9728 16.016 18.837 30 61 . 230 69.21 0.329 0.454 258.37 3.0408 16.348 19.294 31 63.271 71.52 0.322 0.447 263.00 3.1088 16.673 19.745 32 65.312 73.82 0.315 0.440 267 . 56 3.1769 16.992 20.190 33 67.353 76.13 0.308 0.434 272.05 3 . 2449 17.303 20.626 34 69.394 78.44 0.302 0.427 276.48 3.3129 17.608 21.056 35 71.435 80.75 0.296 0.421 280.84 3.3810 17.907 21.480 36 73.476 83.05 0.290 0.415 285.14 3 . 4490 18.200 21.899 37 75.517 85.36 0.284 0.409 289.38 3.5170 18.487 22.312 38 77.558 87.67 0.279 0.404 293.56 3 . 5850 18.768 22.718 39 79.599 89.97 0.274 0.399 297.68 3.6531 19.045 23.121 40 81 . 640 92.28 0.269 0.393 301.75 3.7211 19.316 23.516 41 83.681 94.59 0.264 0.388 305.77 3.7891 19.581 23.908 42 85.722 96.89 0.259 0.383 309.74 3.8571 19.844 24.293 43 87.763 99.20 0.255 0.379 313.66 3.9252 20.101 24.675 44 89.804 101.51 0.250 0.374 317.53 3.9932 20.353 25.052 45 91.845 103.82 0.246 0.370 321.36 4.0612 20.602 25.424 46 93.686 106.12 0.242 0.365 325.13 4.1293 20.846 25.729 47 95.927 108.43 0.238 0.361 328.87 4.1973 21.086 26.155 48 97.968 110.74 0.234 0.357 332.56 4 . 2653 21.323 26.515 49 100.009 113.04 0.231 0.353 336.21 4.3333 21.555 26.870 50 102.050 115.35 0.227 0.349 339.82 4.4014 21.784 27.221 106 AMERICAN GAS-ENGINEERING PRACTICE. of design. For low pressures the saving acquired is hardly justified by the multiplication of cylinders and the losses attendant upon the operation of numerous additional parts. Best practice recom- mends the use of the single-sta:,e compressor up to 70 or 100 Ibs., above that amount (preferably 75 Ibs.) the use of the compound (two-, three-, or four-stage type compressor). Of course, as beforesaid, these matters are largely a matter of design, the theory being that the ratios of the cylinders should be such that the final temperatures 'and M.E.P. in each cylinder should be identical, thereby effecting an equal distribution of the work throughout. LOSS OF WORK DUE TO HEAT IN COMPRESSING AIR FROM ATMOSPHERIC PRESSURE TO VARIOUS GAGE PRESSURES BY SIMPLE AND COMPOUND COMPRESSION. (Air in Each Cylinder: Initial Temperature, 60 F.) One Stage. Two Stage. Three Stage. Four Stage. Percentage of Work Lost in Terms of I j j j 1 j 1 d j i 13 o 1 "3 1 .s i - *- .si "* 1 o | E ft **"* CL S ^ "*** ft ft +s Q^ a "S ft 5 o 11 A 3 1 ji I 1 ji II T J 1 V jl 60 29.9 23.0 13.4 11.8 8.6 7.9 4.7 4.5 70 30.6 23.4 14.1 12.4 8.7 8.0 6.1 5.7 80 32.7 24.6 14.7 12.8 9.7 8.9 6.4 6.0 90 34.7 25.8 16.1 13.8 10.5 9.5 7.3 6.8 100 36.7 26.8 16.9 14.5 10.9 9.8 7.8 7.3 125 41.1 29.2 18.5 15.6 11.6 10.4 8.8 8.1 150 44.8 30.9 20.1 16.7 12.3 10.9 9.1 8.4 200 51.2 33.9 22.2 18.1 14.0 12.3 10.5 9.5 300 61.2 37.9 25.7 20.5 16.6 14.2 12.0 10.7 400 68.7 40.7 28.9 22.4 18.2 15.4 13.1 11.5 500 70.6 41.4 31.2 23.8 19.3 16.2 14.1 12.3 600 80.4 44.5 32.8 24.7 20.4 16.9 14.9 13.0 700 85.0 46.0 34.6 25.7 21.3 17.6 16.1 13.8 800 89.5 47.2 35.7 26.3 22.0 18.1 16.2 13.9 900 93.0 48.2 37.1 27.0 22.6 18.5 16.6 14.4 1000 96.1 49.0 37.9 27.5 23.2 18.8 16.9 14.5 1200 102.8 50.7 40.3 28.8 24.8 19.9 17.7 15.0 1400 108.6 52.0 41.5 29.3 25.9 20.5 18.6 15.7 1600 113.4 53.1 43.5 30.3 26 . 5 20.9 19.2 16.1 1800 117.5 54.0 44.8 31.0 27.3 21.2 19.6 16.4 2000 122.0 55.0 45.8 31.4 27.5 21.5 19.9 16.5 EXHAUSTERS. 107 The following are a few of the formulas used by the B. F. Sturtevant Manufacturing Company, large makers of blowers, exhausters, fans, etc. . for calculating horse-power requisite for the compression of various quantities of air under various conditions: V HP "$). " - W . 33,000 ' (2) ll,UU) 33,000 Ibs. per sq. in.xF HJ - = where V= volume of free air in cubic feet per minute; P= pressure of the atmosphere or suction pressure (absolute) in Ibs. per sq. ft. ; P 1 = pressure of compression (absolute) in Ibs. per sq. ft. Of the above, formula (1) is principally used when the H.P. required is for air which is cooled during compression, as in ordinary compressor practice. Formula (2) when the air is assumed to be compressed so quickly that it does not return to atmospheric temperature. This is the usual case in all blower work. Formula (3) is generally known as the " hydraulic" formula, and in common practice is rarely used above five ounces to half a pound. Formula (4) is usually adopted in the case of positive com- pressors, etc., no allowance being made in this formula for "slip," the calculation being "net." 108 AMERICAN GAS-ENGINEERING PRACTICE. DIRECT-CONNECTED EXHAUSTERS, Nos. 1 TO 8 (Inclusive). ISBELL-PORTER CO., NEWARK, N. J. (For data see page 111.) PLAN OF BED-PLATE EXHAUSTERS. 109 GEARED COMBINATION EXHAUSTERS, Nos. 7 TO 12 (Inclusive). ISBELL-PORTER CO., NEW YORK AND NEWARK, N. J. (For data see page 111.) PLAN OF BED-PLATE 110 AMERICAN GAS-ENGINEERING PRACTICE. COMBINATION EXHAUSTERS, Nos. 13 TO 15 (Inclusive). ISBELL-PORTER CO, NEWARK, N. J. (For data see page 111.) PLAN OF BED-PLATE EXHAUSTERS. Ill CO X X X C00500M hd^hj^dP bbbb' Size of Engine. No. of Blades. Gears, 4D. P. 7 ft. Length over Reducers. to to to to to to 3 05 05 p W W W ,_! W W 3"* tO 3 000 to MH to *r to s f (INCLUSIVE). S CO CO ? ^ g 5' 5 z* 5 i 5 hU p O w to 69 to 09 to ? M K to to B 00 Cn <:- ,s p ft if MM 09 i ^ Cc Oft Oi to p H ^- 01 to p Q CO CO 00 3"* 5 co *- ? ^ CO co F i to i 'Ocooo * **>*, tr XX XXXXX ? on oo fft os os o o Size of Engine. ww wwwww . I No. of I Blades. Length Over Re ducers. Diam. of Shell. OCO OOGOOOOOOO *-h*-H MiHMpioji-iif-io|M r ^i- 1 ooo * *+-*+-*+-* toto tototototo OS OS OS O5 OS 3"* ww 000003 00000^ 05 00 OS *> W) h- coco ^i -^i ~a -j - 3MfT TOO THl/t TO J*f>. 4- aecr.ion HLOUS une. FIG. 27. Patching Rent in Holder-sheet. etc., are being drilled. In the case of a crown-sheet this can be done by simply laying the patch over the hole and weighting it down; but in the case of a side hole, eye-bolts may be attached to the side of the sheet, and the patch clamped on by means of a chain or rope running around the holder, and, by the use of block HOLDERS. 127 and tackle, tightly pulled up and cleated. The eye-bolts may be sawed off after the patch is permanently attached. Capacity. The ratio of holder capacity to daily consumption in small works generally equals 1 to 1. In larger works this ratio is generally decreased, some of the larger plants of the country having only half the storage capacity of their daily output. It is less necessary to have this ratio equal in the case of water-gas than in that of coal-gas. In both instances it should depend considerably upon manufacturing capacity. In no instance, how- ever, in the opinion of the writer, should the minimum storage capacity exceed 85 per cent, of the maximum daily demand. The wash-water from the condensers is sometimes success- fully pumped to and from the relief-holder, thereby reducing the temperature of the water and economizing the quantity used. Salt should never be used in holder-cups for the prevention of freezing, by reason of its injurious effect upon the metal of the holder. TO OBTAIN WEIGHT OF ANY HOLDER. Diameter 2 X pressure in y^th inch X 0.4091= weight of holder in pounds. TO OBTAIN PRESSURE WHICH A HOLDER WILL THROW. Weight of holder in Ibs. -1,1-1 ^~ 7 ovx/% A* = pressure in xVtn men. Diameter 2 X0.4091 WEIGHT AND PRESSURE OF HOLDERS. W areaX5.2r TF=PXareaX5.21. CALCULATIONS FOR HOLDER PRESSURE. Single-Lift Holders. Let P be the pressure of water column in inches; W the weight of holder in pounds; D l ' diameter of holder in feet. If we consider that the pressure changes with the different height of shell above the water-line, the following formula will have to be observed: - . (2) in which S represents weight of shell in pounds; H the entire height of shell; h " the height of shell above water. 128 AMERICAN GAS-ENGINEERING PRACTICE. Two-Lift Holders. If D=the diameter of inner lift; W= weight of the inner lift in pounds; TFi = " " " outer " " " W2= " " ll water in the cup in pounds; $= " " shell of inner lift in pounds ; H height of inner and outer lifts, minus cup, in feet; h= " above water. Then, if only the upper part is working, 0.245 XW 52- v \j-m.*s s^rr i w.v/^j.^A^ 2 .t.* ft) t ^ nnnoQ?> i /o\ ^CK -r^r., TT r U.uuy^o/i I . . \o) should be used. If both are working, the following formula is applicable : In the last or fourth formula we included the bottom ring of the outer section, which is not correct, but the difference is so small that it would not alter the result. The pressures obtained by following the given formulas would be maximum. The minimum pressures, however, can be readily calculated by deducting from the weight of holder, in pounds, the tendency of the gas to rise, in pounds. For example, if C would represent the capacity of the holder above the water-line, in cubic feet, S the specific weight of gas, and A the weight of one cubic foot of air, we obtain, by using formula (1), p 0.245 XTF-CXX4 D 2 WEIGHT OF SNOW (TRAUTWINE). Fresh-fallen snow per cubic foot, 5 to 12 Ibs. Moistened and compact by rain, 15 to 50 Ibs. For the reduction of wind pressure on a circular surface to an equivalent plane area (such as an arched roof or a gas-holder) Prof. Rankine gives ................ 0.5 M. Arson " ................ 0.46 R. J. Hutton " ................ 0.67 W. H.Y.Webber " ................ 0.5 Molesworth " ................ 0.75 G. Livesey " ................ 0.57 Prof. Adams " .............. 0.7854 HOLDERS. 129 Walmisley V. Wyatt Bancroft Cripps Sir B. Baker gives. < < Trautwine Prof. Kernot (of Melbourne Uni- versity) gives 0.5 FORCE OF THE WIND. (O'CONNOR.) 0.56 1.0 (October, 1887) 0.5 0.3 - 0.41 0.5 area of section 0.5 " " " Velocity. Force. Miles per Hour. Feet per Second. Lbs. per Square Foot. 1 1.47 .005 Hardly perceptible. 2 2.93 .012 3 4.40 .044 Just perceptible. 4 5.87 .048 5 7.33 .123 Gentle, pleasant breeze. 10.0 .229 10 14.67 .300 Pleasant, brisk gale. 20.0 .915 15 22.0 1.107 20 29.34 1.968 30.0 2.059 25 36.67 3.075 Very brisk gale. i 40.0 3.660 30 44.01 4.429 50.0 5.718 35 51.34 6.027 High winds. > 40 58.68 7.873 ! 60.0 8.234 Hard gale. 70.0 11.207 50 73.35 12.300 Very high winds. 80.0 14.638 60 88.12 17.715 A storm. 90.0 18.526 100.0 22.872 A great storm. > 110.0 27.675 80 117.36 31.490 A hurricane. 120.0 32.926 130.0 38.654 90 132.02 39.852 140.0 44.830 100 146.7 49.200 150.0 51.462 120 176.04 70.860 130 AMERICAN GAS-ENGINEERING PRACTICE. Paint. As a holder, purifying-box, or gas-machine paint, the writer, after a number of years of experiment, has obtained the best results from the Eclipse graphite paint called "gas-house red/' as manufactured by the Acme White Lead & Color Works. This paint is manufactured of pure graphite. It possesses a heavy body and attractive appearance, and will stand almost any degree of temperature without cracking or scaling. Placing in commission holders, purifying-boxes, mains, or other apparatus. These should be purged by expelling the air which they contain through a double water-sealed siphon, at the outlet of which mav be a test light which may be operated with immunity from explosion. Old paint and rust should first be removed from a holder before re-painting, by the use of wire brushes or scrapers, or, better still, by a sand-blast. Locating a site for a holder should be a matter of the most careful consideration. Other conditions being satisfactory, a first test should consist of making a boring in the ground with an earth auger to a depth of 20 ft. and recording the character of the soil as the borings are brought to the surface. The second test should be the weighting of a square foot of the ground (at a number of places to obtain a general average) with a load of from 2500 to 3000 Ibs., being balanced upon a short piece of 12X12 timber (standing on end). Before the load has been applied, take the elevation of the top of the timber with regard to a bench-mark, then immediately after the application of the weight, continuing to note the amount of settlement, until same apparently ceases. Then by subtracting the last elevation from the first, the total settlement can be ascertained, together with the sustaining quality of the ground, from which data the character of the foundation necessary may be intelligently determined. Piling should be avoided wherever possible, and only re- sorted to where piles can conveniently reach to bed-rock, and where marshy soil or quicksand is encountered it is invariably ultimately cheaper to procure another or different site. The Stacey Manufacturing Co. cite a recent instance of a holder of about 1,500,000 cu. ft. capacity, erected upon soft ground at a cost for piling of 75 cents per square foot, over the whole area of same. These piles were capped by two feet of concrete, composed of good Portland cement, clean coarse sand and broken stone; but the foundations failed immediately upon the filling of the holder tank with water. CHAPTER XI. DETAILS OF WORKS OPERATION. ALL valves about works, mains, or pipe systems should be distinctly marked "open" or "shut," with arrow marking direc- tion of rotation; generally some one valve, right-hand or left- hand, should be universally adopted to prevent confusion, and when so adopted there should be no exception to this rule. There can be no doubt that the standard of gas service for the future, maintained either by municipal legislation or by the gas-engineer, will be based upon the calorific value of the gas. This may be ascertained in two ways: first, by analysis of the gas and by the addition of the heat values of its constituent factors; secondly, by the direct use of calorimeters. There are several types of this instrument, of which the Junker is perhaps in most general use. Another in common use in England is that named Simmance and Abady. A recording instrument has recently been patented by F. N. Speller. The subject of the measurement of temperatures has been best treated by Le Chatelier and Boudouard of Paris, of whose work there is an excellent English translation. Where the Jones jet photometer is used to check the candle power at the works it should be placed in such a position that the temperature will be as nearly as possible constant. As the readings depend principally upon the specific gravity of the gas, they may vary by reason of temperature. It should be periodically standardized against a bar photometer and its value noted. This should occur at no greater interval than once a week where it is used to indicate actual candle power. Its prin- cipal use is a check upon works operation. The reading of water-gages may be done more accurately and the meniscus more clearly defined by dropping into the water a small portion of cochineal, mixed in hot water, which is first filtered and the color fixed by the addition of a few drops of nitric acid. 131 132 AMERICAN GAS-ENGINEERING PRACTICE. The following readings should be taken daily in every works : 1. Temperature of air (average atmospheric). 2. Average barometric pressure. 3. Photometer and calorimeter reading of the gas. 4. Temperature of gas at each stage of manufacture, con- densation, scrubbing, purification, etc. 5. Hourly temperature of gas passing through station-meter. 6. Pressure of gas throughout every point in the works and on the town, the latter being recorded mechanically. 7. Purifiers changed. 8. Records of test for sulphur at inlet and outlet of purifiers. 9. Test-cards from sight-cocks on superheater, showing traces of either tar or lampblack, or probably fixed oil. 10. Gas on hand in holders. 11. Oil on hand in tanks. 12. Tar on hand in tanks. 13. Coke or coal used. 14. Oil used. 15. Percentage of ash or screenings. 16. Station-meter indexed. 17. Air-meter indexed. 18. Average pressure of gas through station-meter (mechanic- ally registered). 19. Differential pressure or resistance of station-meter at maximum load. 20. Average gallons oil and pounds of generator fuel used per 1000 cu. ft. manufactured. The Green fuel-economizer is a special device for heating feed- water, the apparatus consisting of a coil of pipes with an auto- matic scurfing device, through which the waste gases of the superheater pass. Experiments show that these gases enter the economizer at a temperature of about 1500 deg. F., and leave it at between 400 and 700 deg. Through the heat thus absorbed the feed-water is enabled to enter the boiler at 350 deg., effecting a considerable saving of boiler fuel. The only objection to this apparatus is the rather considerable cost of installation in the case of small works, the arrangement being particularly fortu- nate where gas and electric works are combined and the steam production amounts to a large portion of the total manufacturing cost. At the present time the Green Economizer Company are at work on another type of generator, with which they will preheat the blast air, permitting it to enter the retorts at a temperature of about 400 deg., and effecting not only a saving from 6 to 8 per cent, in generator fuel, but a very considerable saving in the de- DETAILS OF WORKS OPERATION. 133 terioration caused by the chill to the checker brick of the other two retorts. Where large valves are frequently used and are important in their nature they should be surrounded by manholes properly covered to facilitate repairs and render them easy of access. Flow of Water. Great loss is sustained about works, offices, etc., by the leaking of various water fixtures, due to a failure on the part of valves to properly seat, and the water escaping therefrom, often without possibility of detection, through -drains and sewers. The following paragraph and table are taken from a paper written by W. L. Calkins, hydraulic engineer: "Few people have even an approximate idea of the quantity of water which may be wasted through small openings, and for this reason I give the following table, which gives the number of gallons of water discharged through various small openings in 24 hours, under a pressure of 60 Ibs. per square inch: Diam. of Orifice, Inch. Gallons. & 61 & 230 A 907 t 3,649 } 14,616 | 32,558 '2 PART II. GAS DISTRIBUTION. CHAPTER XII. NAPHTHALENE. NAPHTHALENE is a hydrocarbon formed in comparatively small quantity (about 13.15 Ibs. per ton of ordinary English coal distilled in coal-gas retorts, according to R. W. Irwin) during the distillation at high temperatures of carbonaceous substances such as coal and petroleum. It has been claimed that naphtha- lene can be formed in the gas after it leaves the retorts and during distribution, but this view is generally held to be incorrect, and from the present knowledge of the subject it seems practically certain that all of the naphthalene found either in coal-gas or coal-tar is produced during the distillation of the coal in the re- torts. The molecule of naphthalene is composed of 10 atoms of carbon and 8 atoms of hydrogen, its chemical symbol being Properties. It is a solid at ordinary temperatures and pres- sures, melting at a temperature of 176 F. It will, however, exist in a state of vapor suspended in gas at temperatures far below even that at which it solidifies as long as the gas is not saturated with it. As soon as the point of saturation is reached the vapor passes directly into the solid state in the form of very light, flaky, flat crystals which occupy a large volume in proportion to their weight. It is this property which renders naphthalene so trouble- some to the gas-manufacturer, since, though the weight contained in a given quantity of gas is small, the crystals occupy sufficient space to seriously obstruct the apparatus and pipes around the works and the services in which they are deposited through chill- ing of the gas. 135 136 AMERICAN GAS-ENGINEERING PRACTICE. Naphthalene obstructions in the apparatus and pipes at the works are usually removed either by flushing with hot water or by steaming, the former being preferable since the steam merely melts the naphthalene, and unless it can escape from the pipe at once it may cool down again and solidify in another part of the apparatus, while the hot water acts not only by melting the naphthalene, but also by carrying it along to a certain extent in mechanical suspension. It is well to use the water in consider- able volume in order to secure this latter effect. Naphthalene is removed from service-pipes and small mains by means of light naphtha, gasoline, or kerosene, which is poured into and allowed to run through the pipes, dissolving the crystals and carrying the naphthalene in a liquid form back into the mains and drips. Sometimes wood-alcohol is used instead of naphtha or kerosene. If the obstruction is very light it may be blown out of the service into the main by means of an air-pump, or even by the lungs. Naphthalene in the form of crystals, like water in the form of ice or snow, will pass from the solid state directly into that of vapor, and thus naphthalene that has been deposited in the pipes hi quantities too small to cause trouble and render it necessary to clean it away will evaporate again and pass off with the gas when this reaches the deposit in an unsaturated condition. This same naphthalene may be redeposited further along in the sys- tem if the temperature changes so as to bring the gas tempera- ture again to the point of saturation with naphthalene, and it is probable that some action of this kind has given rise to the theory that naphthalene can be formed during distribution in a gas which was free from it when it left the holders. Deposits. Accumulations of naphthalene in the inlet-pipes of gas-holders occur most frequently in that portion of the pipe which passes down under the tank-wall and up inside the holder. When naphthalene exists in the pipe as a flocculent lining of approximately uniform thickness throughout a large portion of its length, it can be removed by charging the gas with the vapor of light naphtha, gas so charged being able to pick up naphtha- lene deposited in the form of loose crystals. The gas can be charged with the vapor either by injecting the naphtha into the inlet-pipe in the form of a spray, by means of a steam-jet, or by filling the drip at the bottom of the pipe with naphtha, which gradually evaporates into the gas passing over it. Naphthalene in the condition named can also be removed by blowing steam into the pipe in sufficient quantity to raise the temperature to the point at which the naphthalene will either melt and run down into the drip, from which it can be pumped out, or vaporize and NAPHTHALENE. 137 be taken up by the gas. In all of these methods it is necessary to have gas flowing through the pipes, so that the naphthalene as it is vaporized will be picked up by the gas and carried along with it out of the pipe, and there is always danger that the naph- thalene so picked up will be again deposited at an inconvenient point during the further travel of the gas. When naphtha vapor is employed this will condense at the same time that the naph- thalene is deposited, dissolve the latter, and carry it along to the nearest drip, thus preventing any obstruction, but when steam is used the liability is great that the obstruction will be merely transferred from one point of the pipe system to another. In many cases the presence of naphthalene is not suspected until it has formed, on the inside of the portion of the pipe which rises through the water in the tank, a layer of such thickness that it is detached from the sides of the pipe by its own weight and falls into the elbow making the turn from the vertical into the horizontal part running under the tank-wall, where it forms a compact mass. Such a mass seems to be very little affected by heat or with naphtha in the liquid form. Hot water may be used in several ways. At one works, the water, heated by means of steam in an old boiler equipped for the purpose, the pressure being run up to between thirty and forty pounds per square inch, was conducted to the holder by a temporary line of pipe. Removing Deposits. The operation of cleaning out the holder- inlet was carried on as follows : The holder was practically emptied of gas, the time chosen being that when the stock of gas was small enough to be contained in the other holders, and kept so as long as possible, though this was merely to keep the weight of pipe to be handled at a minimum, as the holder could be raised through the outlet-pipe without interfering with the work. Through a hole drilled in the top of the bonnet over the inlet- pipe was inserted a one-inch pipe on the bottom of which was screwed a 1 X 1 in. L, the direction in which this L pointed being marked on the pipe at the top. This pipe was made long enough at the start to reach down to the bottom of the holder-inlet, and a number of short pieces of pipe were provided to screw on as the holder rose. The pipe fitted loosely in the hole in the bon- net, but a practically gas-tight joint was made by wet cloths wound round the pipe at this point. The pipe was supported and turned by means of a bar handle clamped on at the proper height. A hose connection being made between this pipe and that from the hot-water heater, and the water being turned on, it issued from the opening in the L in a jet which broke up and dissolved the naphthalene and ran down into the drip, from which it was pumped, bringing the naphthalene with it both in solu- 138 AMERICAN GAS-ENGINEERING PRACTICE. tion and in suspension. The drip-pump was kept working all the time the hot water was being run in, so that the water should be pumped out before it cooled down and dropped the naphtha- lene. The water-pipe being turned so that the stream played against all parts of the inlet-pipe, a very complete cleaning could be given by this method. Another method of washing out the naphthalene is called "plunging." In this the inlet-pipe is sealed with water, the flange at the top of the vertical pipe outside the holder taken off, and the drip-pump removed. The pipe is then rilled as full of hot water as it is possible to have it without filling up the horizontal run coming to the holder from the station-meter. A plunger or wooden cylinder, about 18 inches to 2 feet long and a little smaller in diameter than the pipe, fastened to a pipe handle, the axes of the pipe and the cylinder coinciding, is then inserted and worked up and down, so as to impart a surging motion to the whole body of water. The surging back and forth of the water dislodges the naphthalene that is not dissolved, and the large pieces rising to the surface are fished out, the remaining fine par- ticles being pumped out with the water. It is rather a difficult matter to get the large body of water contained in pipes above 6 in. in diameter moving with sufficient velocity to dislodge the compact masses of naphthalene; but if the motion can be produced, "plunging" is a very effective method for the removal of naph- thalene from the pipes. When naphtha or any other liquid solvent is used it is not economical to pour it into the pipe by itself, since if this is done it will cut channels in the deposit, through which it will run to the drip before it is fully saturated with naphthalene. A better effect can be obtained by pouring water into the inlet until it is filled to half its height. Then from four to five gallons of sol- vent naphtha are poured in and the water slowly pumped out at the drip, so that the liquid gradually falls in the main. The consequence is that the solvent, which forms a layer on the top of the water, is forced to act on the whole of the interior surface of the main, both where the latter is upright and where it is nearly horizontal. The time during which it acts on the surface is deter- mined by the rate of pumping, and thus may be made sufficiently long to complete the solution of the naphthalene. When the solvent has reached the elbow, the rate of pumping is diminished in order to give it time to act on the greater horizontal section of the pipe which then becomes exposed to it. By this method of treatment the whole of the inner surface of the pipe is freed from naphthalene, which is completely removed from the main through the pumps. NAPHTHALENE. 139 Preventing Deposits. The various methods employed or proposed to prevent the deposition of naphthalene in a solid state in the mains and services may be divided into two general classes, those which remove the naphthalene from the gas at the works by means of some absorbent, and those which consist in add- ing to the gas-vapors of liquids having a solvent action on naphtha- lene and approximately the same vapor tension as that sub- stance. Methods of the first class have been adopted quite generally on the continent of Europe and to some extent in Great Britain. In them the gas is washed or scrubbed with an oil which possesses the property of absorbing naphthalene vapor, the process being exactly similar to that by which the ammonia is removed from the gas. The operation is usually carried on in a rotary mechanical scrubber of the Standard type, in which either creosote-oil, heavy tar-oil, or anthracene-oil is used instead of water. A small amount of benzol, from 4 to 8 per cent, by weight, is added to the oil used, to saturate it and thus prevent it from absorbing benzol from the gas and reducing the illuminating power. According to Dr. Bueb at Dessau, Germany, an anthracene-oil boiling between 480 and 750 F. is used, and 176.4 Ibs. (19 to 20 gallons) of this oil removed, from 706,000 cu. ft. of gas, naphtha- lene to the amount of about 200 grains per 1000 cu. ft. The capacity of the oil for naphthalene increases with the tempera- ture, and the naphthalene scrubber should follow the tar-extractor and work on comparatively hot gas. In some cases, however, two or three compartments of the ammonia scrubber are used. After being saturated with naphthalene the oil can be put in a still and the naphthalene driven off, or it can be chilled, crys- tallizing the naphthalene, which is then removed by means of a filter-press. In either case the oil can be used over again. If working on a small scale, it may be more economical to run the saturated oil into the tar-tank and sell it as tar. The frequently employed method of running into the gas, as it goes out into the district, naphtha which becomes vaporized and travels along with the gas, belongs to the second class. The naphtha is usually added to the gas at the outlet of the governor, being blown into the gas in a finely divided spray by a small steam-jet atomizer. The success of this method depends upon the precipitation of the naphtha in liquid form at the time and place at which the naphthalene is deposited, so that the latter will be dissolved and carried off by the former, and as this does not always occur the remedy is not always successful. J A modification of the above method, known in English as the Hastings carburation process, consists in forming in the gas as 140 AMERICAN GAS-ENGINEERING PRACTICE. it goes out from the works into the street-mains a mist of oil, the oil used being one that is not volatile at ordinary tempera- tures. This mist, in very minute drops, is formed by blowing the oil through specially constructed atomizers by means of a portion of the gas, which is compressed to a pressure of 75 Ibs. per square inch. It is found that in this state of minute sub- division some of the oil will remain in the gas until it reaches the farthest point in the district; the conditions which will cause the deposition of naphthalene at any point will also precipitate enough of the oil to dissolve this naphthalene and carry it off as a liquid. It is stated that at Hastings one gallon of oil used in this way for each 166,000 cubic feet of gas is sufficient to do away with all trouble from naphthalene stoppages, although these begin to show as soon as the process is discontinued. Much information on the subject of prevention of deposits of naphthalene in street-mains and services can be found in Vols. LXXII to LXXVI of the Journal of Gas-lighting. According to Dr. Paul Eitner, in the Journal fur Gasbeleuch- tung, Vol. 42, p. 89, One gram of benzine will dissolve 0.32 grams of naphthalene at 32 F. 0.407 grams of naphthalene at 50 F. From tables of the vapor tensions of benzine and naphthalene it is found that One cubic foot of gas can take up 3.25 grams of benzene at 32 F. 5.72 grams of benzene at 50 F. 9.45 grams of benzene at 70 F. One cubic foot of gas can take up 0.0005 grams of naphthalene at 32 F. i 0.0045 grams of naphthalene at 50 F. 0.0155 grams of naphthalene at 70 F. These figures show that gas, if saturated, can carry 2000 times as much benzene as would be required to dissolve the largest amounts of naphthalene the gas can hold at 32 F. Oil-tar, after being separated from oil and entrained water, is suggested as a remedy for naphthalene, the gas being scrubbed through it in the same manner as with anthracene oil, when it will absorb about 25 per cent, of its own bulk of naphtha- lene.. NAPHTHALENE. 141 A Continuous Naphthalene Test may be arranged as follows: Dissolve 150 grains picric acid in one quart warm distilled water. Bubble 1 ft. to 1J ft. gas per hour through 100 c.c. of this solution. If gas contains an excess of naphthalene, a heavy precipitate will appear. Avoid use of rubber tubing in making test. If gas contains tar, filter through a tube containing cotton. Tar will color solution brown and prevent naphthalene precipitate forming. If gas contains an excess of ammonia say more than 5 grains bubble gas first through 5 per cent sulphuric-acid solution. Ammonia will color the acid red-brown and prevent precipitation. One or more of the absorption bottles like that represented in Fig. 28 may be used. FIG. 28. CHAPTER XIII. MAINS. Capacity. The gas-consumer is connected with the gas-supply in the works holder by underground pipes or mains with their branches and service-pipes. These pipes are generally of cast iron, although in the natural-gas districts steel screw-joint pipe is largely used, and the connections to services are made by tapping into the top or side as preferred. The formula for calculating the capacity of cast-iron mains was given by Clegg and attributed to Pole, being known as Pole's formula, and is stated as follows: - gl where V= cubic feet delivered per hour into atmospheric pressure; d = internal diameter of the pipe in inches; h = pressure on gas at entrance in inches of water-head; g= specific gravity of the gas, air=l; 1= length of pipe in yards. The constant 1350 is arrived at when considering a fixed fric- tion derived from very old experiments. Some engineers assume this figure only for pipes 10 in. or over in diameter, taking 1250 for 6- to 10-in. pipes and 1000 for pipes under 6 in. diam. This formula is of course applicable to low-pressure distribution only. When higher pressures are employed, such as exist in high-pres- sure distribution or natural-gas practice, a formula must be em- ployed taking into consideration both entrance and terminal pressures, influence of compression and temperature, such as that developed by Professor Robinson: 142 MAINS. 143 where T = 461 +37 = 498 deg. F., the absolute temperature at the maximum density of water; TI = absolute temperature of gas after delivery (461+ deg. F.); T2 = absolute temperature of gas in the main; d = diameter of the pipe in inches; L= length of main in miles; pi = initial and p 2 = terminal gage pressure in Ibs. per sq. in., and g= specific gravity of the gas transmitted (that of natural gas being 0.6). The Cox gas-flow computer, a slide-rule device, was calculated from this formula: = 33. 3> |g where PI and P^ are the initial and terminal pressures absolute (14.7+gage pressure) in Ibs. per sq. in. A more accurate deter- mination by actual test is made by the Pitot tube, described in the chapter upon Pressures. J, D. Shattuck in 1905 made a re- port upon the various formulas for this purpose to the Ohio Gas- light Association, subsequently published in Progressive Age. In comparing the capacities of mains it is thus seen that this varies as the square root of the fifth power of the diameter. Laying Mains. The depth at which mains should be laid should depend upon two conditions, namely, climate and the protec- tion of mains from the crushing stress of heavy traffic. It is cus- tomary, with regard to climate, to place the top of the pipe below the nominal frost-line, which varies from 6 ft. in Canada to some 24 in. in the Southern States. For ordinary purposes, however, 30 in. below the ground generally gives satisfactory results. Such laying, however, depends somewhat upon topography and local conditions, such as the presence of sewer-lines and -services, water- mains, etc. It is necessary, of course, to lay pipe upon a grade sufficient to completely drain it, and it is economical and good practice to lay as long a line as possible without putting in drip- pots. As an offset, however, to this is the increased expense of ditching not only in the initial installation, but the subsequent laying of service-lines. The writer strongly advises that at no time shall a smaller size of cast-iron pipe than 4 in. diam. be laid. There are occa- sions where districts will not require a larger size than 3 in. for an indefinite period, but these are rare and generally can be sup- , plied by long services of wrought-iron pipe. 144 AMERICAN GAS-ENGINEERING PRACTICE. A good average weight for 4-in. cast-iron pipe is 220 Ibs. per length of 12 ft., or in the neighborhood of 18 Ibs. per ft. A lighter pipe than this is not advised, as it is impossible to anticipate what crushing stress it may have to endure, to say nothing of the ad- vantage of strong bells for calking. Specifications for various classes of cast-iron pipe and fit- tings, as designed by the Committee on Research for the Ameri- can Gaslight Association, are appended to this volume. Gradient. The minimum grade permissible for draining mains should certainly in no instance exceed one inch per 100 ft. How MAWS SHOULD BE FIG. I- CORRECT P/PE B EDO INC <]\ BELL HQL. 77777: BL C K ING LoUHTfffSUNK. 'J ^BELL HOLE,: f/ //f V/ 7 *~^&lfiW3 y^T^^.^m^f'l TT7777\ FIG. z - /ncofiRECT Pi PE Betiowe v / BL oc*//v6 on TOP orD/ 7- FIG. 29. Proper Method for Laying Mains in Trench. of main. This, however, is about the minimum permissible in a sewer. Where a greater hydraulic head as well as hydraulic radius is obtained, the hydraulic radius in gas-mains is so exceed- ingly small and the viscosity of the condensation (composed largely of tar and other oily ingredients) is so great that better practice suggests a fall of at least a quarter of an inch, or better 0.318 in. per length of 12 ft. of pipe. This is more necessary in low-pressure mains than in high pressure, the latter having less condensation and the velocity of the gas tending to free the main from liquids collecting in trapped portions. Where the soil is bad and shifting, the bottom of the ditch should be blocked. This should be done in any event where the size of the pipe exceeds 18 in. diam. These blocks, usually 2X12X20 in., should be below the level of the bed of the ditch, as per Fig. 29, th whole surface presented to the pipe being MAINS. 145 flush and forming a continuous bearing for it. The same gra- dient or fall of the pipe is maintained throughout. District mains should be invariably laid with an allowance for extension of business, and the calculation should be based upon a system, which, when loaded to capacity, would not show a pressure drop at the moment of peak-load in excess of 25 per cent., 20 per cent, being better practice. Pipe=joint Specifications. The following are the specifica- tions of the United Gas Improvement Co. of Philadelphia, for the making of lead joints: ''Each spigot end should be driven home into the bottom of the bell, the joints should be well calked with jute packing, the greatest care should be taken that the packing is calked as solid as the yarning-iron and heavy hammer will calk it. This joint in itself should be gas-tight. The calking should be done evenly, so that all parts of the joint will be evenly solid. The lead should be of the best quality of soft lead and the amount required per joint approximately as follows: 3-in. pipe about 2J Ibs. lead. 4-in. " " 4 " " 6-in. " " 1 " " 8-in. " " 10 " " 10-in. " " 14 " " 12-in. " " 18 " " 16-in. " " 28 " " 18-in. " " 32 " " 20-in. " " 35 " " "The weights given above have been found to be sufficient if the yarning has been properly done. The lead should be evenly, gradually, and thoroughly calked, so that when finished all parts of the joint will be of an equal decree of hardness. In no case should a joint be completely calked at one part before the other parts of the joint are taken in hand. "In layin.s; mains, when it is required to turn a corner, or to make a bend for any purpose, elbows or specials should always be used. It is bad practice to make a bend by making each joint give a little and thus dispensing with the use of a special. Quarter bends and eighth bends can be always obtained, and special angles can be made by the use of circle bends. These specials can be cut so as to obtain almost any required an^le. "Great economy will result from the proper handling of the ditch or trench in which main is to be laid. The earth, stone, gravel, etc., should be separated upon being excavated with large forks, each according to its kind, and in back-filling should be re- 146 AMERICAN GAS-ENGINEERING PRACTICE. laid in strata, the large stones first, then smaller stones, and finally gravel with the dressing of loose earth, each stratum being sepa- rately and thoroughly tamped into place. This back-filling, when properly done, will not settle and leave a depression in the street. "No larger ditch or trench should be excavated than is actu- ally needful for the size of pipe to be laid. An approximate table of the width of a trench for various sizes of pipe is herewith given. 4-in. diameter, width 20 in. 6-in. " " 22 in. 8-in. " " 24 in. 12-in. " " 30 in. 16-in. " " 35 in. 20-in. " " 40 in. 24-in. " " 44 in. 30-in. " " 50 in. 36-in. " 56 in. In excavating the bottom of the trench should be carefully graded and bell-holes made at intervals of 12 feet. The bottom of the ditch shall be such as to give a continuous and positive bearing for the main. "In running lead joints, standard pipe being used, the spigot end being first rammed home, the space formed by the junction of the spigot and bell shall be filled and calked with strands of tarred oakum until the space is filled to give the lead depth required for the size of pipe, and driven up sufficiently tight to cause the yarning to spring back when impinged. This lead depth to be left in the bell should vary with different sizes of pipe and should be about as follows: 4-in. diameter pipe, lead joint to be 1J in. deep. >_: ( i tt (i ( ( t ( i <. -1 i 1 1 u n t i n it i ( < i -i& i c 1 1 .< li ..i M if ri 16-in. " " " " " il 2 " " 20-in. " " " " " " 21 " " o/i ; >t a it u u it it 01 << " ^Tt~iii ^x 30-in. " " " ll " " 2J " " 36-in. " " " " " " 2J " " All joints when run should be flush with the face of the bell, and should they be driven up in calking more than in. they should be re-run. "All joints should be invariably tested before joint-holes are MAINS. 147 back-filled. It is best where feasible to test long sections of pipe by pumping up an air pressure, using a pressure-gage and noting loss of pressure due to leakage. The test pressure should not be less than 5 Ibs. per sq. in. (10 in. of mercury). But where this method is impossible each joint should be covered with heavy soap- suds while under gas pressure and an examination made for bubbles. "It sometimes becomes necessary to use a split sleeve in the case of a broken main, although its use is to be avoided. When used, however, it is an invariable rule that the two ends of the pipe should be bound together by wrapping with unbleached muslin or canvas, a mixture of red lead and white lead being spread in the folds of the cloth, the whole securely wrapped with strong twine or cord, and coated with shellac. The width of the wrapping should be such that the sleeve projects on either side at least 2 inches. After this is completed the split sleeve is to be applied, care being taken that there should be no leak at the flanged joint. It is sometimes necessary if the flanges are not faced that the joint between them should be made with tar board which has been softened by soaking in warm water. It is better, however, to face them by grinding them upon each other with fine emery powder. "It is well to purchase all cast pipe and specials uncoated, var- nished, or tarred, as defects in the casting, sand-holes, etc., are frequently concealed in this manner, even to the temporary stand- ing of gas pressure, but in the long run such stoppages will give way and leaks occur. " When it is necessary to work upon a broken main, etc., in frozen ground, it is convenient to thaw the ground in the follow- ing manner: A recess 6 or 10 inches deep is dug over the section of main to be worked on, and of the desired length. This is filled with a good quality of unslaked stone lime and several buckets of water thrown thereon. The recess is then covered closely with old cement sacks and boards and left for several hours. In this manner the frost can be drawn from the ground for a con- siderable depth. " When it is necessary to cross a bridge with a gas-main, the practice should be to run from the lower level in the street to the upper level on the bridge a pipe of larger diameter than the pipe to which it is connected; for instance, let A = the main and F=the risers and specials crossing the bridge, then when a mam is 3 in. it requires the riser to be 6-in. diam.; for A 4 in., B must be 8 in.; a 6-in. main requires a 10-in. riser; an 8-in. main a 12-in. riser; a 10-in. main a 14-in. riser; a 12-in. main a 16-in. riser, and a 16-in. main a 20-in. riser. Should the pipe crossing the bridge 148 AMERICAN GAS-ENGINEERING PRACTICE. be exposed, expansion joints should be placed on either side to take up vibration and change of temperature. "All records of drips and valves should be carefully kept not only in a file index, but also entered upon the company's map, and extensions and changes corrected thereon and kept up to date." The following paragraph, taken from the gas educational trustees of the American Gaslight Association, cannot be too forcibly urged upon the attention of engineers and foremen: "In the laying of street mains it is of the utmost importance to see that all pipes are on a slight incline or gradient, so as to drain all condensation to a given point which is situated at the lowest part of the main, where all the condensation is collected by means of drip-wells. If the pipes are not laid on a perfect gradient there would be a collection of water in the various parts of the pipes where sags or traps occurred, which would hinder and stop the flow of gas according to the depth of the trap and the amount of water therein." For all sags in the pipe-line, drips, or traps, proper drip-pots, such as described in the standard specials of the American Gas- light Association, should be provided. Cement Pi pe= joints. The following information -upon this subject will be found in the Proceedings of the American Gas- light Association: "The cement joint for street mains is cheaper than the lead joint. It is more rigid, and under changes of temperature is more apt to remain tight. The lead joint is more easily cut out than the cement joint, more easily repaired, and has the advan- tage of ' coming' and 'going' with the changes of temperature, which, in the case of the cement joint, might fracture the pipe." (See Vol. 13, p. 47.) "The joints commonly employed in this country for connect- ing together the separate lengths of cast-iron pipes are the lead joint and the cement joint. The lead joint, while, as a rule, more expensive than the cement joint, has the advantage of being more easily cut out, more easily repaired, and of allowing the pipes to expand and contract, under the influence of changes of temperature, without fracture, since the lengths can move in the joints. On the other hand, the cement joint is cheaper and more ri^id than the lead joint, and when properly made will remain tight under almost any possible conditions. A line of pipe laid with cement joints if exposed to changes of temperature will not show small leaks at the joints as will one laid with lead joints, but, on the other hand, it will probably be fractured in one or more places. In most instances the choice between lead MAINS. 149 and cement joints is determined by the relative disadvantages of a number of small leaks, no one of which is lar^e enough to be dangerous, and one large leak, which, though it will be quickly detected, may cause great damage before it can be repaired. In one large city lead joints are used in the heart of the city, where gas from a large leak would be apt to accumulate in cellars, sewers, and electrical conduits, with danger of disastrous explosions, and cement joints are used in the outskirts, where the conditions are favorable for the gas from a leak passing away into the open air without forming an explosive mixture in any confined spaces." (See Vol. 17, p. 137.) "Use Portland cement. Natural cements are not uniform in quality, and, as a rule, are too quick-setting to permit of their use with safety. In selecting the brand, take a relatively quick- setting Portland. If the cement sets too slowly there is danger of the finished joint being disturbed before setting. Use the cement neat no sand. Use the cement as dry as possible, so that it requires hammering the yarn against it in order to bring the moisture to the surface. When sufficient water is added the cement will still appear crumbly in the pan, and will just retain the impression of the finrers when squeezed in the hand. The cement should be used immediately after mixing, only enough being mixed at one time for, say, two joints; if it lies unused over five minutes, it should be discarded. The cement remaining in the pan should be entirely removed before mixing FIG. 30. Cement Joint. up any new cement. In mixing cement, first determine the quantity required for one joint, and the quantity of water re- quired for this cement, and then always use the cement and water by measurement. Use jute yarn, untarred. When the joint is made the yarn and sides of joint may be moist or damp, but should not be wet (Fig. 31). The finished joint should con- sist of one roll of yarn (A) of the exact circumference of the pipe, twisted and driven tightly to the bottom of the bell; then a solid mass of cement () extending to a point about 1.5 in. back of the face of the bell; then a second roll of yarn (C); then 150 AMERICAN GAS-ENGINEERING PRACTICE, a facing of cement (D). Do not make a large fillet extending to the outside diameter of bell. In entering the cement be very careful to completely fill the whole space. A wooden pusher shaped something like a yarning-tool is useful for pushing back the cement after it has been entered by the hand. Sometimes a roll of yarn is used to drive the cement back, the yarn being withdrawn, more cement entered, and the process repeated until the desired quantity has been entered. After the first yarn is in, and before the joint is made, the pipe should be thoroughly bedded and tamped in between the bell-holes, to prevent any movement of the joint after it is made. When the joint is made, it should be protected from the sun. As few joints as possible should be made in the rain. All joints should be tested before being covered up. The test is made by connecting gas pressure to the new pipe through a meter, thus measuring the amount of leakage, if any. If the meter indicates leakage, the holes should be found by using soap-suds on the joints. Fire should never be used. Better still, an air-pump and mercury-gage may be employed. The joints should be tested only after the cement has set sufficiently to prevent its being hurt by the soap- suds; where feasible, this should be on the following day. "In the sketch (Fig. 31) is a side view of a 6-in. cement joint, with part of the hub removed, showing cement and packing. In the sketch C is the cement, P packing. After the pipe has been 'sent home ' graded, and the joint equalized as near as possible, 1 in. of hemp packing is firmly driven in as shown in the pre- FIG. 31. Another Form of Cement Joint. vious illustration; then 1 in. of cement and 1 in. more of pack- ing, followed by 1J in. of cement, of which in. is on the outside of hub, and slopes from center of rim down to pipe as shown. To make this joint requires 3i pounds of cement and sand mixed dry 2 parts of cement to 1 of sand and 3 ounces of hemp packing. The joint can be made in 15 minutes." Lead Pipe=joints. "In making a lead joint in 6-in. cast-iron main, the first step in the operation, after the spigot end of one length has been inserted in the bell of the other and the length driven home, lined up, and fixed in place by the tamping of a MAINS. 151 little dirt around the middle of it, is to fill solidly with packing a portion of the joint space between the spigot and bell, the amount of space so filled being determined by the depth of lead which it is desired to have. For ordinary straight work with 6-in. pipe the depth of lead may be taken at 1.5 in., and the joint space will therefore be filled with packing to a point 1.5 in. back from the face of the bell. Jute packing, either plain or tarred, is usually employed. Packing which has been allowed to absorb a small quantity of tar can be driven tighter than plain pack- ing, but, tar being cheaper than jute, it is hard to avoid the pres- ence of too much tar in tarred packing, and for this reason plain packing is often given the preference. A sufficient number of strands of packing should be twisted to form a rope of a diam- eter a trifle larger than the width of the joint space, and this should be cut into pieces of such length that the end will come into close contact when a piece is placed around the outside of the spigot end of the pipe and pulled up tight. One of these pieces is used to lift the spigot end as it is inserted into the bell of the pipe previously laid, and is sent home with it, thus keep- ing the spigot central in the bell and avoiding the necessity of wedging it up after it is in place. This piece of packing is driven solidly into place in the bottom of the joint space by means of a calking-hammer and packing-iron, and other pieces are in- serted one at a time, the joint in each ring being put say one- fourth of the circumference away from the joint in the pre- ceding ring, and each driven home, a sufficient number being used to fill the joint space to the required depth, leaving 1.5 in. for the lead. The packing must be driven hard and the finished layer must be of uniform depth, so that the lead space will be uniform all around the pipe. A clay roll or other form of joint runner is then placed around the spigot end of the pipe, being brought tight against the face of the bell, and so set as to leave a triangular space, having its base on the pipe and its apex on the face of the bell slightly above the inside edge, which the lead can fill and thus make it certain that when driven the joint will be of the shape shown in the cut. Molten lead is run into the joint and this space until both are completely filled and the lead stands above the highest point of the inside edge of the bell, the lead being poured in through an opening or 'gate ' left on top of the pipe. When the lead has hardened the joint runner is removed, and the 'gate ' or lump of lead where the opening for pouring was made is cut off. The lead is then chiseled all around the pipe with a cold chisel and calking-hammer. This separates the lead from the surface of the pipe, and makes a groove in which the first calking-tool, the face of which is about & in. 152 AMERICAN GAS-ENGINEERING PRACTICE. thick, can fit. The lead is driven all around with this tool and then with tools successively increasing in thickness about J in. until the full width of the joint has been reached. The work with each tool should be begun at the bottom of the pipe and carried around each way, finishing up at the top. The thickness of the last tool used should not be greater than the width of the joint, and the driving with this tool should cut the lead off sharp with the inside edge of the bell, otherwise there is danger that the force of the blows will be expended against the face of the bell instead of doing the full amount of work that it should do in compressing the lead in the joint. - In order to have the tools fit the joints exactly it is well to have them made in sizes vary- ing in thickness by A in., though it is only necessary to use on any joint tools varying by J in., the proper sizes being selected. The position in which tools are naturally held when calking the joint will give it the finished shape shown in the cut, if the joint runner has been put on properly and sufficient lead used. There will be required for making a 6-in. lead joint about 7 to 8 Ibs. of lead and 7 to 10 oz. of jute packing. A good workman should be able to average nearly 3 joints an hour for a day's work." TABLE OF CEMENT AND YARN REQUIRED, AS PREPARED BY Size of Pipe. Cement in Quarts. Cement in Pounds. Water in Pints. Yarn in Ounces. 4" 1 to IJ 2.25 to 4.10 fteti 4 6" H to 2 4.10 to 5.50 H to if 6 8" 2 to 2$ 5.50 to 6.87 1| to li 8 10" 2to5 6.87 to 8.25 li to 2 10 12" 3 to 4 8.25 to 11 2 to2J 12 16" 4 to 5 11 to 13 f 2J to 2$ 15 20" 5 to 6 13J to 16J 2J to 3 20 24" 8 to 8 20 to 23 5 to5i 27 30" 7 to?i 19 to 21 4 to 4* 27 Advantages of Various Joints. " In England and on the con- tinent of Europe a great variety of joints for cast-iron pipe have teen devised and to a certain extent used. These include mov- able flange joints, clip joints, collar joints, screwed joints, bell- and-sprrot joints in which the joint is made by means of a vul- canized rubber ring, and bored and turned joints as well as the fixed flange joints, bell-and-spigot joints of lead or cement, and ball-and-socket joints, which are practically the only joints used in this country, and are therefore the only ones considered in this article. Flange joints allow of an easy removal, when desired, MAINS. 153 of any one of the various pieces of pipe. They are, however, very rigid, and their use is confined to lines of pipe above ground and at the works. On long, straight lines of flanged pipe one or more expansion joints should be provided to relieve the pipe of the strains that would be thrown upon it by its expansion and contraction under the influence of changes in temperature. Ball- and-socket joints are expensive and are used only for lines where great flexibility is necessary, as in laying pipes under water. FIG. 32. " Cup-and-ball " or swivel joint, especially used in crossing 1 rivers, or any occasion where it is necessary for the pipe to " flex." Disjointing Cement Joints may be most easily effected by the heating of the pipe bell and joint, after the fashion of melting out lead joints. Cement joints should never be made in pipe recently exposed to the sun, without first reducing the temperature of the pipe to that of the atmosphere by wet cloths or water. The fresh joint should be protected from the heat or cold by shrouding it in wet or dry burlap or bagging respectively. In cement joints untarred yarn is to be preferred, making a more homogeneous joint. Combination Joints. A frequent practice is to lay the pipes with cement joints, except at intervals of from six to twelve lengths, where a lead joint would be put in to act as 154 AMERICAN GAS-ENGINEERING PRACTICE. an expansion joint the location being marked and noted, and the lead joint occasionally examined. This should make cement- jointed pipe practically as free from liability to fracture as lead- jointed lines." The whole secret of success in joint-making lies in the yarn and calking. Every yarn joint should be in itself perfectly gas-tight, and every joint yarned or finished should be driven up perfectly tight with the calking-tools. The first requisite of cement joints is that no more cement should ever be made than is to be used within five minutes, all of the remaining cement being thrown away and discarded, as after that time the setting has begun to take place. In the smaller sizes of pipe, where it is inadvisable to use a chisel in cutting, roller cutters, such as the Hall, manufactured by the Walworth Mfg. Co. and the Rodefeld Mfg. Co., may be found advantageous. The rollers in these cutters may be removed, retempered, and sharpened. It should be remembered as the basal principle of all cast- iron pipe-joints, whether lead or cement, that the first yarn driven should be of itself independently "gas-tight." If this work is properly executed, the yarn being tightly calked and conscien- tiously worked over, the material subsequently used is a matter of .secondary importance. High=pressure Pipe=joints. In laying high-pressure mains, which should be of extra heavy wrought-iron or steel pipe, where the usual coupling is used, it is good practice, after carefully lubri- cating the joints, to make up four or five sections of pipe hand- tight, when the whole may be screwed up with a power-winch. This should be done so that each joint is turned to a point where the threads completely disappear within the socket or coupling, and the whole will be found not only a most effective joint, but capable of extraordinary speed in execution, thereby greatly facilitating and expediting the labor of main-laying. For the taking up of bends in the pipe, obviating the effects of imperfectly calked joints, and to reduce the electrolytic damage of current jumping around the joint, a pipe has been designed, under the name " Universal," in which the hub and spigot ends are machined to fit tightly without any packing whatsoever. The method of bolting sections together by flanges and a section of the joint are shown in Fig. 33. Fig. 34 illustrates not only how to allow for the extra length caused by the joint, but also, by the use of short pieces and a nipple, how any desired length may be obtained. For ordinary pressure Universal joints should not be drawn close up. When ordering pipe for exact measurements allow, in MAINS. 155 addition to the pipe lengths, for each male end as specified in the table below, which gives the average exposure of the joint when made up as represented by letter A in Fig. 34. FIG. 33. Universal Joint. FIG. 34. Universal Joint Connections. 1, the hub end of a 4-in.'pipe; 2, 4-in. close nipple: 3, 4-in. elbow; 4, 4-in. X2-ft. pipe; 5, 4-X9-in. pipe; 6, 4-Xli-in. space nipple; 7, 4-in. tee; A, i in., which is the exposed part of the joint. Diam. Pipe, Averaged Exposed Portion of Joint Inches. represented by A, Inches. 2 A 3 A . 4 t 5 i 6 A 8 * 10 f 12 f 14 The following are some of the usual forms of high-pressure pipe-couplings: 156 AMERICAN GAS-ENGINEERING PRACTICE. Dresser An^le-coupling. Insulating Coupling, Style 10, for Special or Dresser Style, Cast-iron Pipe. Section of the Dresser Pipe-joint. A, spigot; B, V-shaped bell of pipe; C, cement; D, malleable iron ring; Fand G, bolt and nut; H, asbestos ring; R t rubber ring. Clamp for Matheson Joints. Split Sleeve for Repairing Broken Bell on Cast-iron Pipe. Clamp, Style 4, for Repairing Leaks on Regular Hub and Spigot Cast- iron Pipe-head or Cement Joints. Light Split Sleeve, Style 13, for Repair- ing Wrought-iron Pipe. Split Sleeve, Style 12, for Wrought- iron Pipe. Large enough to go over Dresser Coupling in Case of Accident. Insulating Coupling for Dresser, Style 9, Split Sleeve for Repairing Broken Cast-iron Pipe. Cast-iron Pipe. FIG, 35. MAINS. 157 Although high-pressure service merely exaggerates the con- ditions of low-pressure transmission, the increased duty is so severe and these conditions so strongly emphasized as to make necessary and essential a perfection of engineering, material, and workman- ship which would in more or less degree be otherwise commercially dispensable. The pipe used in high-pressure work should be extra heavy iron or steel, and of the best quality of meter, with the closest approximation to an equality of texture throughout, free from chilled spots, cores, sand-holes, etc. The thr3ads should be taper and constitute the best order of machine work, which threads in the transportation, assembling, and fitting of the pipe should receive infinite care, to prevent bruis- ing, chamfering, or stripping. These threads should be carefully examined by a competent inspector immediately before " making - up," all pipe with defective threads being discarded, their threaded section being cut off and the threads re-run. Although this may seem an extravagance, it is in reality economical practice, and should be adhered to without deviation. 'The quality of valves, cocks, fittings, etc., is also most important. Commercially speaking and to all practical purposes, the quality of brass varies between two extremes, its highest refinement and efficiency being reached at an approximate composition of red brass consisting of 90 parts copper, 10 parts tin, and 2 parts zinc, while at the other or opposite extreme we find a yellow brass as low as in copper, as 50 parts copper and 50 parts zinc. The various grades and qualities of brass, commercially used and for the manu- facture of fittiir s, lie between these extremes, although the former is occasionally and the latter frequently reached. Red brass of the composition named attains a tensile strength of 68,000 Ibs. per square inch, while the yellow alloy runs as low as 10,000 Ibs. per square inch tensile strength, the various compositions and formula now in commercial service varying between these extremes very exactly in ratio with the preponderance of copper and the amount of tin and zinc. As the proportion of lead, zinc, and tin becomes higher and the preponderance of copper less in the mixture obtained each ingre- dient preserves more distinctly its individual characteristics and attributes. Going from red to yellow brass, the tendency is to revert from the close-prained tenacious copper to the spongy zinc. In alloying elements of such widely varying gravities as copper, lead, and tin, when such elements are in a molten state some separation or segre- gation must take place, the heavier metals going to the bottom of the molten mass in the order of their respective weights. It is 158 AMERICAN GAS-ENGINEERING PRACTICE. necessary to overcome this tendency by a certain amount of agita- tion ; if this is incomplete, the result is an unequal distribution of the elements throughout the admixture. This condition tends to destroy any possible homogeneity in the structure and fiber of the resultant casting, and such inequality in the metal causes rapid excoriation, unequal grinding, as well as scoring of working parts and bearings where they meet. If we take two fittings, one a red and another of the yellow metal, and place them on an anvil, striking them in succession with a sledge-hammer, using the same degree of force, it will be observed that while the red-brass casting may become slightly distorted, the brittle yellow-brass casting will fly in pieces. This is due to the extreme tenacity, ductility, and elasticity of the red brass obtained from its copper component, a peculiarity which the writer has observed in fittings during experiments with the Barrett pipe- forcing jack. In a number of instances where obstructions were encountered, under the enormous amount of pressure from the jack, the fitting was completely distorted without breaking, but, even in its distorted condition, preserved its tightness against leaking. Moreover, it was found even in the case of the standard- weight fitting that the pipe in the connection ruptured under the stress before the fitting would give way. Another illustration of the extreme tenacity of the red brass is shown by the fact that it is nearly 50 per cent, more difficult to machine, polish, and buff than is yellow casting, being prima facie proof that a metal which will resist the incursion of the machine tool will possess paramount qualities from a wearing standpoint, and possesses the highest resistance to all forms of erosion. While copper is not ordinarily affected or corroded by such agencies as moisture or acids inducing rust and oxidation, yet tin, zinc, and lead are especially affected by these, and we may there- fore say that fittings are susceptible to rust, oxidation, or corrosion in direct ratio with the amount of tin, zinc, and lead which they contain. Inasmuch as corrosion attacks that portion of any structure which is most delicate, its inroads principally affect the threads and working surface of these fittings, and leaks are more often occa- sioned by this agency than are usually conceded. Especial attention is here called to the fact that in testing a fit- ting for high-pressure gas or air, the hydraulic test is only good as indicating the tensile strength of the fitting and not to indicate tightness, it being found that valves or cocks found tight under the 300 Ibs. of water pressure frequently leak when subjected to 40 Ibs. of air. This fact seems little known among either manu- facturers or engineers, but it will be found, as a rule, that when a MAINS. 159 fitting is found tight under a pressure of 40 Ibs. it will be tight under any other reasonable pressure, or, generally speaking, up to its safe working capacity or even to the rupture point of the metal. Globe=valves, Tees, and Elbows. The reduction of pressure produced by globe-valves is the same as that caused by the follow- ing additional lengths of straight pipe, as calculated by the formula: Additional length of pipe= 1 14 X diameter of pipe 1 + (3.6 -diameter) ' Diameter of pipe, Additional length Diameter of pipe Additional length 112 4 7 10 3 13 3J 4 16 20 5 28 6 inches 36 feet .7 8 10 12 15 18 20 22 24 inches 44 53 70 88 115 143 162 181 200 feet The reduction of pressure produced by elbows and tees is equal to two-thirds of that caused by globe-valves. The following are the additional lengths of straight pipe to be taken into account for elbows and tees. For globe- valves multiply by f : Diameter of pipe, Additional length Diameter of pipe. Additional length, 1 1J 2 2j 3 3J 4 5 6 inches .2 3 5 7 9 11 13 19 24 feet 7 8 10 12 15 18 20 22 24 inches 30 35 47 59 77 96 108 120 134 feet These additional lengths of pipe for globe-valves, elbows, and tees must be added in each case to the actual length of straight pipe. Thus a 6-inch pipe 500 feet long, with 1 globe-valve, 2 elbows, and 3 tees, would be equivalent to a straight pipe 500 + 36 + (2 X24) + (3X24) = 656 feet long. Joints for High=pressure Mains. All sockets or couplings shall be extra heavy, of the best quality of metal, and have taper threads. Preferably these joints should be tight and free from leakage without the use of "dope," but where some joint com- pound is necessary litharge and glycerine are best used. Where flange-joints of any kind are used, the gasket should be made of ^-in. lead wire, the ends of which are soldered together. Where valves are used upon high-pressure lines or storage- tanks instead of cocks, these too should be of the extra-heavy ammonia type, although even these will be found to give more or less trouble, unless of a first-class quality and carefully selected. Main=regulators. Where high-pressure mains are controlled through automatic regulators the equipment should invariably be in duplicate, the regulators being connected into the line in 160 AMERICAN GAS-ENGINEERING PRACTICE parallel, and each equal to sustaining the maximum load of the entire line. The regulators should be connected in with proper valves and possess by-passes between their inlets and outlets, all of which connections to be flanged, to expedite ready removal and replacement. All of the above should be surrounded by proper brick or concrete manholes to afford accessibility. Drips. All traps, pockets, or depressions in almost every high- pressure fine should be dripped after the method of low-pressure practice. This may usually be done by cutting into the line a tee (looking down and whose opening is equal to the diameter of the pipe) into whose run a short section of pipe is connected, which is duly capped and fitted with a small relief -pipe terminating at some convenient place and fitted with a pocket-head pet-cock, which latter acts as a " bleeder." Through an arrangement of this kind the condensation accumulating in the drip can be periodically "blown off." This condensation is usually created by the change of vapor tension due to the varying compression upon the vol- ume of gas in the main, extending from the maximum pressure during peak load hours to possibly atmosphere or merely holder pressure (if the service be a booster or feeder line) , or at least con- siderably reduced during the period of minimum demand. Anchorage. All bends and curves in high-pressure mains should be firmly anchored in order to prevent gyration ; the straight runs should also be heavily anchored, perhaps about twice as often as the expansion joints (about one every 500 ft.). Expansion joints and lateral branches of all sorts should also be strongly anchored to prevent buckling and thrust. The tendency of a high-pressure main to " writhe " is much greater than is generally known, for, in addition to the initial pulsations caused by the compressor, there is a reflex which creates a powerful " gas-hammer." Expansion Joints should be placed not less frequently than one every 1000 feet. Testing High=pressure Mains is done much after the fashion of low-pressure work, with the exception that a portable air-com- pressor, say 6 H.P., direct-connected to a gasoline-, alcohol-, or vapor-engine, is generally used. An outfit of this kind will also be found extremely convenient for a number of purposes; it can have in its equipment a centrifugal pump and hose connections, which will be found of great convenience in emptying ditches, cesspools, drips, etc., of water, with a saving of time and labor. Pneumatic Tools. The compressor may also be fitted with a pneumatic hammer into which cape and diamond-point chisels may be used for cutting pipe; and with calking-tools for driving up joints. These tools should fit the chuck loosely so as to move freely in the workman's hand. The calking done by the pneu- MAINS. 161 matic hammer is far superior to that done by hand, being equal throughout, and especially driving home the lead at the bottom of the joint and underneath the pipe, which is usually slighted in handwork. It has the further advantage of time and economy, and in permitting the ordinary laborer to do a better job of calking ALCOHOL . t Benzine ran*. FIG. 36 Naphthalene Removal Vaporizer. than that usually accomplished by a skilled and expensive work- man. Pipe Deposits. To remove stoppages in the mains, services, meters, house-pipes, fixtures, and burners, and to clear out naph- thalene, tar, and other hard stoppages, the writer has found it 162 AMERICAN GAS-ENGINEERING PRACTICE. convenient to vaporize wood-alcohol or benzine and inject it into the mains by means of a vaporizer (Fig. 36), a diagram of which is herewith given. A quantity, say 20 gallons, of alcohol is put into a tank and admitted through a sight-feed into a drum, where it is vaporized by a steam-coil. The inlet of this drum is duly sealed by a pipe- trap in order to prevent the return of the vapor or the exit of the gas into the alcohol-tank. This alcohol vapor, passing out through another trap, is admitted into the mains and carried for- ward by the gas, experiment showing it to have a travel of at least 3 miles. It instantly dissolves all naphthalene and invari- ably attacks and makes soluble other similar substances. Ten or 15 gallons per 1,000,000 cu. ft. thus admitted into the mains for a day or so, say twice a year, will be of incalculable value in cleansing the system, especially where Welsbach service is extensively used. Leaks. The question of leakage, or a large portion of what is known as "gas unaccounted for," should be a matter of con- roftG6t> -ROUND T BAA f OR LOCATING FIG. 37. Pavement-piercing Bar. stant attention upon the part of the superintendent. Of course a large portion of this seeming discrepancy is by reason of change of temperature, either during the process of works distribution or after storage, gas varying -^-% of its bulk approximately for every degree Fahrenheit over 32 above zero. There is, however, in all systems a certain amount of leakage due to bad joints, which occur either from poor construction, change in temperature, or instability on the part of the ground or foundation where laid. The entire system of every gas company should be periodically MAINS. 163 "barred." An iron bar (Fig. 37) with a loose handle for removing, large at one end to form an anvil for the sledge and tapering at tha other, should be driven down at the bell end of a pipe, such joint being first definitely located. Great care should be taken that the bar should not be driven with sufficient force to injure the pipe, and to this end it is better to use a bar with a malleable point than a steel bar, which is apt to cut. The bar then being removed from contact with the bell, leaking gas should be sought in the hole thus made, first by the sense of smell and afterwards by the application of a match. Test for Leakage. Under conditions where, by reason of a comparatively odorless gas or for other reasons, it is impracticable to discover leakage by the sense of smell, test may be made by applying at suspected points a paper saturated with a solution of palladous chloride from which metallic palladium is precipitated in the pres- ence of traces of carbon monoxide; the reaction being as follows: PdCl 2 +CO+H 2 O=Pd+2HCl+CO 2 . The blackening of the paper indicates the presence of CO gas. Records. A measurement should then be taken in the direc- tion of the run of the pipe (equal to one length of the pipe) and the next joint located, when the experiment can be repeated. All leaks discovered* should be marked, reported, dug up, and re- calked. Where the calking lead drives up too far, a new lead joint should be run and its tightness ascertained by the applica- tion of heavy soap-suds. This sort of work, together with all repair work, can be greatly facilitated by the use of accurate records in the office, recording the location of all pipes, drips, valves, services, etc., indicating the direction of flow, the juncture of feed-line and crosses, etc. In order to bring this information to the office, where a proper record can be made and filed, the writer suggests the use of a card (Fig. 38), which should be supplied to the foreman of main construction, who can fill in thereon, with a rule and pencil, the location of pipe, distance from property line, class of fittings, location of valves, drips, crosses, etc., and the direction of fall. From these cards a map can be made, showing an entire district, which will be found valuable in the regulation of pressure and the addition of extensions, after which the card should be filed for future use. Service Connections. It is doubtful whether under any conditions it is good economy to use galvanized pipe for ser- vices, inasmuch as nearly all agencies which tend to destroy black iron will also attack the zinc coating of galvanized pipe. Medium- weight steel pipe will be found far better. 164 AMERICAN GAS-ENGINEERING PRACTICE. It is good practice in connecting a service with the main to tap the latter on top and screw therein a street T. The street L is then screwed into the street T at its side outlet, thereby form- ing a swing joint. The chief advantage of this connection is that gas can be cut off by the opening in the T from the service while it is being laid, which opening can be also used for examining the IJ M il DISTANCE TO PROPERTY LINE DISTANCE TO PROPERTY LINE DEPTH < DEPTH STREET DISTANCE TO PROPERTY LINE DISTANCE TO PROPERTY LINE i CO s = - 1 s E $ g j f E < E DISTANCE TO PROPE ENGTH OF BLOCK NOICATES POINT TWENT OPERTY CORNER. rE DIRECTION OF FALL. OCATION OF ALL VALVES re POSITION AND SIZE O ;LASS OF PIPE, SIZE OF - 1 i * 5 B E | i 1 i __ FIG. 38. Main and Service Chart. service in case of trouble. It also relieves both pipes from either horizontal or vertical strain in settling or crawling (Fig. 39). There are two methods of cutting cast-iron pipe, both of which can be recommended. The more convenient, especially for sizes under 12 in., is the Hall cutter, which can be used after the man- MAINS. 165 ner of wrought-iron pipe-cutters; otherwise the pipe should be cut around with a diamond-nosed chisel until a ring at least ^ in. deep has been formed, when the pipe may be severed with the aid of a dog-chisel. In pipes over bridges, contraction and expansion, together with vibration, must be allowed for. Wrought-iron pipe is gen- t (rift re mm FIG. 39. Plug for T Connection to Prevent Gas Escaping while Laying Service Irises. erally used in preference to cast, and at either end expansion joints, or, better still, the Dresser sleeves, are placed. There should be valves on either side of the bridge to control the flow of gas in case of accident. These pipes should be kept thoroughly coated, inasmuch as the sulphur in engine smoke, in the case of railway bridres, is most deleterious in its action. It is the custom of a number of companies in the United States to base their extension of mains into unoccupied territory upon one prospective consumer to every 100 feet of main. The ad- vantage of this system seems to be demonstrated by the best practice. All valves in a main system should systematically and con- 166 AMERICAN GAS-ENGINEERING PRACTICE. sistently be either all right-handed or all left-handed, that is, closing in the direction of the hands of a clock or the reverse. This, more than anything else, prevents confusion and the pos- sibility of having a valve in the system closed without the likeli- hood of discovery. One of the great nuisances in gas distribution is the formation of iron carbonyl. It may possibly be the result of unoxidized purifying material, but is more likely the result of gas coming in contact with new iron borings, such as the tapping of a large number of services into a new section of main is apt to produce. It appears generally at the burner tip and may be remedied by the admission of water into either main, services, or purifying- boxes to complete the oxidation. The general advantages of cast-iron over wrought-iron pipe for gas purposes are: first, its greater ability to resist the cor- rosion of the soil; secondly, its greater thickness between internal and external diameters, permitting better service connection and abolishing the necessity of additional fittings for such connec- tions, thereby reducing the liability to leakage. Repairing Breaks. In case of broken mains a temporary repair can be made by bandaging with cloth between the folds of which are wrapped copious layers of soap, pipe-clay, or, better still, Tucker's cement, portions of which filling having been pre- viously forced into the crack or crevice of the pipe before the application of the bandage. The permanent remedy depends upon the nature of the injury. Should the break run around the circumference and the entire damage be included within a lateral space of 4 or 5 in., a split sleeve may be used. Should, however, the break run lengthwise the pipe, the better practice is to cut out the injured section, replacing it with new pipe, the final joint being made with a solid sleeve which is slipped over the joint. When a split sleeve is used, the pipe must be first thoroughly cleaned of all dirt and rust, and if it is settled it should be blocked back into proper grade and alignment. A strip of unbleached muslin, wide enough to cover the break, with a margin of 6 or 8 in. on either side, and long enough to circle the pipe twice or more, should be smeared thickly with putty or Tucker's cement, or a mixture of equal parts of white and red lead and linseed-oil, and wrapped tightly around the pipe above the break. A split sleeve can then be applied so as to cover the break, with a margin of at least 4 in. on either side. The joint between the sleeve and the pipe may be made as follows: A number of pieces of millboard soaked to a pulp in hot water may be forced between the sleeve and the pipe and tightly corked. When this MAINS. 167 is dry a lead or cement joint of the regular .type, the former pre- ferred, may be made on either end of the sleeve. When it is necessary to remove altogether a damaged section of pipe, the pipe should be cut at a distance not less than 8 in. FIG. 40. Method of " Cutting" in a Fitting (Correct), Using a Solid Sleeve. FIG. 41. Method of "Springing" in a Fitting (to be Avoided) without Use of Sleeve. prior to appearance of the break or crack; this cut may be made either by the use of regular pipe-cutters, or by cutting around with a diamond-nosed chisel and severing with a dog-chisel. When the new section is installed, aligned, and graded before sliding the sleeve, which in this case should be solid, into place, the spigot ends, which must just meet, should be brought to- gether and wrapped with unbleached muslin, prepared as before described, with the use of the split sleeve. The solid sleeve may then be slid over the bandage and the joint made as before de- scribed in the regular manner. Flour or meal in small sacks has on several occasions been used to choke dangerous fires occurring through leakage in man- holes. Main=stoppers. In bagging off a main that is likely to be internally coated with naphthalene or rust, the rubber ba; should be inserted in a canvas cover in order to protect the rubber sur- face from the action of the oily deposit. This may be placed by use of a bag fork, which is a simple wire contrivance, with blunt end. Where the main is under considerable pressure, it should be doubly bagged, two separate taps and bags being placed on each gas-head, and' as an additional precaution, where the pressure is especially hrrh, a patent gas diaphragm stopper, con- sisting of a contrivance of canvas and wires, may be placed before the bag in a separate tap. It is well to use bags one size larger 168 AMERICAN GAS-ENGINEERING PRACTICE. than the diameter of the tap to be plugged. These bags should always be inflated by the use of a small hand bicycle pump, and never by the lungs, as the breath condensation is deleterious to the rubber, to say nothing of the effect upon the workmen of the gas inhaled. Gas bags after use may be preserved by being inflated with dry air, the necks being corked, instead of tied, with wooden pins or plugs. The bags should then be coated with tallow and stored in a damp place. Successful efforts have been made to bag off a main with water, extra-strong bags being used. Repair Work. Pressure may be shut off and the end of a main plugged temporarily by the use of a large compact ball of cloth or cord, fitting the pipe, to which proper straps have been firmly attached to facilitate ready removal. COSTS OF INSTALLING MAINS. Excavation Costs. The following table, for which the writer is indebted to M. E. Malone, will be of value in estimating labor operations, and constitutes a very fair average of work in hand- ling different kinds of material that the average laborer can handle in a specified time, in cu. ft. per man per hour. MATERIAL HANDLED PER MAN. Cu. Ft. per Man-hour. Asphalt (3.5-in. and 6-in. concrete) 4.298 Sand and clay 24.700 Clay " 19.220 Sand and broken stone 22.000 Loam 35.000 Broken shale 17.330 Cost of Loading and Hauling Cast=iron Pipe. Much of t*he following data is from Gillette's Handbook of Cost Data. Three men assisted by a driver averaged 5' lengths of 12-in. pipe loaded from a flat car to a wagon and the pipe was rolled down the plank runway. This same gang would unload a wagon in 6 minutes. As each length of pipe weighed nearly short ton, the wagon load was 2.5 tons. It therefore cost 5 cents per ton to load and 2.5 cents per ton to unload the wagons, wages of men being 15 cents per hour; but this does not include the lost time of two horses during loading and unloading, which is equivalent to about 2 cents per ton. The total fixed cost of loading; and unloading was 10 cents per ton, including team time. The hauling costs 12 cents per MAINS. 169 ton per mile where 2.5 tons are the load (wages of team and driver 35 cents per hour) and the team returns empty. Good hard level roads are required for so large a load. If the haul is short and this loading gang of 3 men walks along with the wagon, the cost of hauling becomes 25 cents per ton-mile in- stead of 10 cents. Pipe should never be shipped in hopper-bottom cars, for the difficulty of unloading adds very much to the cost. I have had a gang of 6 men who unloaded only 75 lengths of 12-in. pipe in 10 hours from a hopper gondola into wagons. Each length weighed 800 Ibs., making 30 tons the day's work at 30 cents per ton. This work was by hand, no derrick being available. Trenches for water-pipes in the northern United States are usually 5 ft. deep from the surface of the street to the axis of the pipe. In the South trenches are only 3 ft. deep. Water- pipe trenches are usually dug not less than 18 to 24 ins. wider than the inside diameter of the pipe; and just before the pipes are laid a gang of men enlarge and deepen the trench for a short space where each pipe joint is to come; this is called digging the " bell-holes." The bell-holes enable the yarners and calkers to make the joints properly. It is usually not necessary to brace the sides of a trench that is only 5 or 6 ft. deep. Cost of Trenching. At Corning, N. Y., a trench for a 10-in. water-pipe was excavated 2.5 ft. wide X 5 ft. deep X 1500 ft. long, which equals 600 cu. yds., in 4.5 days by 24 men, or at the rate of 6 cu. yds. per man per 10-hour day, equivalent to 1 1 cents per running foot or 25 cents per cu. yd. The backfilling was done in three days by 2 men and 1 horse with driver, usin; a drag scraper and a short length of rope, so that the horse worked on one side of the trench while the two men handled the scraper on the opposite side, pulling the scraper directly across the pile of earth. In this way the backfilling was made at a cost of 1.1 cents per linear foot or 2.5 cents per cu. yd., there being no ram- ming of the backfill required. This is a remarkably low cost for backfilling and one not ordinarily to be counted upon. The material was a loamy sand and gravel. At Rochester, N. Y. With the size of trench and kind of mate- rial practically the same results were obtained as above: One man excavated 8 cu. yds. a day at a cost of 19 cents per cu. yd. ; 1 man backfilled 16 cu. yds. a day at a cost of 9 cents per cu. yd. Total cost of excavation and backfill, 28 cents per cu. yd. Cost of Trenching, Great Falls, Mont. The Great Falls (Montana) Water Co. excavated 25,500 cu. yds. of earth, 1900 cu. yds. of loose rock, and 1500 cu. yds. of solid rock in trenching 170 AMERICAN GAS-ENGINEERING PRACTICE. V for a 6-in. water-pipe. The work was done by company labor (not by contract), wages being $2.25 for laborers, and the cost was 34 cents per cu. yd. for excavation and 3.5 cents more per cu. yd. for backfilling and tamping. If wages had been $1.50 a day the cost would have been 23 cents per cu. yd. for excava- tion and 2.5 cents per cu. yd. for backfilling. Cost of Trenching, Astoria, Oregon. A. L. Adams states that in trenching for the Astoria (Oregon) Water-works in 1896 the first contractor averaged only 7 to 8 cu. yds. per man per day. Later on another contractor, even in the rainy sea- son, averaged nearly 10 cu. yds. per man per 10-hour day of trenching (including backfilling) at a cost (including foreman) of 17.5 cents per cu. yd., wages being $1.70 a day. The mate- rial was yellow clay dug with mattocks and shovels. Cost of Trenching, Hilburn, N. Y. W. C. Foster gives the following data on 17,000 ft. of trenching for water-pipe at Hil- burn, N. Y. The trench was 4 ft. deep for 4-in. to 8-in. pipe. The digging was hard, the banks being full of cobbles and fre- quently caved in. The streets were not paved. The cost of trench- ing and backfilling was 10.1 cents per lin. ft., wages being $1.35 for laborers and $3 for foreman. Cost of Trenching and Pipe-laying, Providence, R. I. In Engineering News, June 28, 1890, E. B. Weston, Engineer Water Department, Providence, R. I., gives very full records of pipe- laying costs. The tables on page 171 are given by him and are based upon many miles of trench- work. Wages in all cases above were $1.50 a day for laborers trench- ing and laying, $3 a day for foreman, $2.25 for calkers, and $2.25 for teams, which probably refers to teams without driver. Carting was in all cases $1 a ton. Allowance for tools (item 4) was made on a basis of 7.25% of items 1 and 2. Short lengths, 15 to 50 ft., of 6-in. pipe cost 34 cents per foot in easy digging to 45 cents in hard digging for excavation, laying, and backfilling, wages being as above stated. The trench for a 24-in. pipe 19,416 ft. long and 6.6 ft. deep cost 32 cents per cu. yd. for excavation and backfill with wages at $1.50 a day. A 48-in. main was laid for $1.65 per ft., including digging, laying, calking, and backfilling. A 16-in. pipe 374 ft. long passed under two railway tracks, and the cost of trenching, laying, and backfilling was 50 cents per ft. An 8-in. pipe was laid across a bridge, and the cost of boxing, laying pipe, etc., was $1.32 per ft., while for a 12-in. pipe the cost was $1.50 per ft. MAINS. 171 EASY DIGGING, SAND. Size of Pipe, In. 4 6 8 10 12 16 20 1. Trenching *.. . 2. Laying .0422 .0129 .0518 .0162 .0611 .0191 .0707 .0219 .0798 .0249 .1445 .0370 .2088 .0497 3. Foreman 4. Tools, etc. . . . 5. Calking .0130 .0041 .0106 .0158 .0050 .0107 .0188 .0059 .0108 .0216 .0069 .0111 .0244 .0078 .0118 .0303 .0134 .0159 .0360 .0191 0301 6. Lead, Sets. Ib. 7 Teams . . .0224 0070 .0320 0090 .0431 0115 .0553 0136 .0683 0160 .0950 0203 .1203 0216 8 Carting 0078 0149 0208 0275 0346 0518 0746 9. Total .1200 .1554 .1911 2286 .2676 4082 5602 MEDIUM DIGGING, GRAVEL, ETC. Size of Pipe, In. 4 6 8 10 12 16 20 24 1. Trenching *.. . 2. Laying 3. Foreman 4; Tools, etc. . . . 5. Calking .0597 .0189 .0180 .0056 0106 .0697 .0220 .0206 .0065 0107 .0790 .0249 .0234 .0075 0108 .0883 .0279 .0265 .0084 0111 .0974 .0307 .0294 .0093 0118 .1700 .0440 .0350 .0154 0159 .2400 .0577 .0373 .0214 0301 .3019 .0639 .0396 .0602 0757 6. Lead, 5 cts. Ib. 7. Teams .0224 0070 .0320 0090 .0431 0115 .0533 0136 .0683 0160 .0950 0203 .1203 0216 .1600 0228 8. Carting .0078 .0149 .0208 .0275 .0346 .0518 .0746 .1317 9. Total .1500 .1854 .2210 .2586 .2975 4474 6030 8630 HARD DIGGING, HARD OR MOIST CLAY. Size of Pipe, In. 4 6 8 10 12 16 20 1. Trenching *... 2 Laying . .0860 0271 .0959 0303 .1053 0333 .1147 0362 .1300 0411 .2261 0530 .3264 OfifiQ 3. Foreman 4. Tools, etc. . . . 5. Calking 6. Lead, 5 cts. Ib. 7. Teams .0260 .0081 .0106 .0224 .0070 .0286 .0090 .0107 .0320 .0090 .0314 .0099 .0108 .0431 0115 .0343 .0109 .0111 .0553 0136 .0372 .0118 .0118 .0683 0160 .0428 .0201 .0159 .0950 0203 .0452 .0283 .0301 .1203 0216 8. Carting .0078 .0149 .0208 .0275 .0346 .0513 .0746 9. Total. . . 1950 2304 2661 3036 3508 5250 7104 * Including backfilling. In all cases the depth of the trench was such that the center of the pipe was 4 ft. 8 in. below ground surface. Trenches were ordinarily 2 ft. wider than the pipe and 5 ft. plus half the diameter of the pipe deep. Such trenches were dug, the pipe laid, and backfilling made at the following rate per laborer engaged: 172 AMERICAN GAS-ENGINEERING PRACTICE. Diameter Pipe Feet Length Inches. Material. per Day. 6 Easy earth 21 .0 6 Medium earth 17.2 6 Hard earth 10.3 8 Easy earth 19.3 12 Medium earth 13.4 20 Easy earth 9.0 24 Medium earth 4.4 Earth excavation in trenches where digging is easy cost 20 cents per cu. yd.; rock excavation averages $2 per cu. yd., run- ning as high as $3 per cu. yd., wages being $1.50 per day. Where long pipe-lines are to be constructed a line of levels should first be run and, the drip of the pipe being taken into account, the entire length should be laid off by the engineer in convenient units of equal volume. Although the quality of the soil, unforeseen obstacles, etc., will vary to some extent the unit rate of progress, this will serve as a basis for the checking of the progress of work from day to day besides establishing a basis for the computing of future oper- ations. Careful records should be made of the character of the soil, nature of obstacles, etc., encountered, which should be filed as a portion of the daily data and should be ultimately classified for future reference. The labor itself should also be handled on the unit basis, the work being so laid out in units and decimals thereof that a check can be kept upon the individual output. Upon these data (where not hampered by Unionism) the labor may be classified under the respective headings A, B, C, and D, of which B may represent the normal or average and be paid the standard rate of wage, the normal being obtained either from empiric data or the immediate work done. A may con- stitute a class of labor whose output is in excess of the average or B class, to whom a bonus of from 10 to 20 per cent should be paid, depending upon their marginal efficiency. It must be re- membered, however, that in addition to their work per se these men constitute the " pace-makers " of the force and should be paid accordingly. Class C will be formed of those falling immediately below the average and should be constantly culled for dismissal, while all those crossing the dead-line between Class C and Class D, or, let us say, showing a deficiency of 15% helow the average of Class B, should be discharged from the work at once. MAINS. 173 174 AMERICAN GAS-ENGINEERING PRACTICE. c K 3 O O O (M O O CO rH O C O O 00 O * (N O >0 as S f 8 S d CD 06 1C CO O rH CO d t* c^ 00 t- 3 (N 8 8 S X 8 8 Tt< C rH 1C CO 1C O t- CO (N 00 TM S 3 I HP * CO CS O ^ I s - oo' d d 3 t, * g* b CO 1C (N (N a CO O O rH rH O C O O CO O W rH CO CO g -2 *M CO O> O (N 2 S . O C CO CN CN CO p o v O O CN rH O O CO c5 ^o to $ g ^ d 8 " (N CO d 06 a N '~ l "ft S CO ^ ^ CD 8 8 8 o 8 co 28 8 ^ S S S CO rH | g - 8 rt (N O N T3 (N O O co O O "O CO O CO 2 i 8 8 2 8 5 N O .2 1 C5 05 gjj rH " 1-1 O W S O O CD O O CO CO O 00 C^l C^ C^ 00 ~ B . 1 Oi CN O O O rH CO CO CN d 1-1 d N I i I 1 i I 1 CO 'C 00 *C 00 O CO rH rH W CO O O O rH O S 8 S g S g 00 06 >c d d >o rH d d CO r-I CO * 1 rH ^ 00 g. CD 8 8 S S 8 8 9 O O O O O S iO O O 00*0 ? * O O O CN rH CD CO d d d co" -J I 0001-00 O rH CO I- CD C tN J qf| 8 8 2 o 8 CD ON 8 8 8 o o oo CO o *o w u co 06 d d oo d d d M 0) ' C . C *T3 -T3 " * "S * **^ MIC '"wS fe'iS-S ^ a ora 6t ^ H '"-^ ^ g 3 5" Illiillillii |rt|"S|"S|c|rt4|.S U Q O O Q U OJ! j! - i-H CM 00 CM 00 Oi CM i-i b- iO iO CO O CM O l> 00 CM 00 CM Pipe per oot of Sq X 3 GO GO I-H ' iOCMO5 i i Tt< CO O5 CM to GO N- -^ 00 CO '-' l> 00 |> Tt< i i Tt< -^ 00 !> ooooooco l>COOOt^ oioocor^ Oi001>O 1>Ol>OOO O5 CM CMtoO5TjHTtiiooOCMOOOt>- i ii ii iCNCO^OI>O5OCM i CMiOOO' iTft>. CMCMCMCOCOCO CM CO ^"^ OS O5 ^^ ^O O^ ** CM t^ OS CM CO O^ CO T " H CO CO CO CM CO ^^ CO CM *~4 C'l w^ "^ O t^* 00 t^* CO ^O CO 00 CM ^ *O CO ^^ !> '"^ *-O O^ CO t^* i"H i-O 1 "~ 1 t^* "^ 00 O^ O CM t^* OS O 00 00 i i Oi CO Tt* iO -^ ** !> CO r^ CO O i-t CM i Oi CO Or- i :83I3$ -* co ^ oo i i> os SERVICES. 205 206 AMERICAN GAS-ENGINEERING PRACTICE. steel pipe. These connections are special patterns and are usually tested under 150 Ibs. of air pressure. The clamps are especially galvanized, and the fittings made of FIG. 45. High-pressure Cocks Connected in Service -clamps. material and composition adapted to this class of work, the keys having greater lap and the bodies being carefully ground and oil- polished. Fig. 45 shows a number of these connections, they being made preferably with a swing- joint. A wooden plug is shown inserted in the hole in the main through the fittings which prevents the escape of gas while the service is being completed, after which it can be removed and the fittings permanently plugged. Should it become necessary at any time to remove the service- clamp from the main, a wooden plug may be again inserted and the clamp removed without further escape of gas. Fig. 43 indicates a number of .fittings used in this connection, FIG. 46. Types of Mueller Century Service- clamp. especially manufactured for the purpose, and Fig. 49 indicates the Mueller High-pressure Gas-main Drilling-machine, operating Ion boring-bars, so that the hole in the main may be drilled through either the clamps illustrated in Figs. 46 and 47, or through any of the fittings of Fig. 43. This is of especial advantage where exceedingly high pressure SERVICES. 207 is used, it being good practice to use gas-service cocks in connec- tion with the clamps and tees, both to prevent the escape of gas FIG. 47. Combined High-pressure Clamp and Service Tee. FIG. 48. Lead Gasket Filling under Saddle of Service-clamp. and to enable at all times uninterrupted access in the construction or maintenance of the service. The writer believes that the double clamp, illustrated in Fig. FIG. 49. Mueller High-pressure Tapping-machine. 46, in connection with the swing-joint and service-cock, illustrated in Fig. 45, is the ideal high-pressure connection. Where services are to be subjected to pressure of over 20 Ibs., extra-heavy wrought-iron pipe or steel pipe, together with extra- heavy fittings, should be used. This is not so much by reason of its safe working-pressure as by the saving in leakage and rigidity attained. 208 AMERICAN GAS-ENGINEERING PRACTICE. FIG. 50. General Scheme for High-pressure Service Connection. High-pressure Service Connections. The scheme of arrangement fop connecting a high-pressure system, as illustrated in the above diagram, Fig. 50, working from right to left, is as follows: On the gas main, which is pre- sumed to be a steel, wrought-iron, cast-iron, or Universal pipe, the yoke service clamp with proper lead gaskets is attached and tightly clamped. The main being tapped through the orifice of the yoke, a high-pressure main cock is inserted, into which in turn is inserted a service tee having one end plugged, and a service ell screwed into its side port. Into this ell the service pipe is screwed and the run of the service taken up to the curb, where a curb cock, protected by a proper service box, is intersected. Continuing the run of the service, it enters the building, and immediately inside the wall a high-pressure female lock-wing meter cock is interposed, from whence the service continues to a tee, one side having a plug or pet cock for dripping purposes, and into the other a riser, which proceeds to the inlet of the regulator. This regulator is of the opposed diaphragm balance-valve type with a by-pass connecting its shell with the safety vent pipe, in case of breakage to the diaphragm of possible leakage. From the outlet of the regulator the riser is connected with a by- pass upon which is placed a mercury seal, which is so designed that in case of " blowing the seal" the mercury will overflow into a receiving trough and by-pass the gas supply to the safety air-vent until replaced into its cup. The function of the seal is to act as an additional safety valve and should have a resistance only slightly above the maximum pressure required at the outlet of the meter, in order that in case of accident occurring to the proper working of the regulator the seal will blow and the gas escape through the fresh-air vent operating the alarm whistle, 1 rather than forcing its way all through the meter and into the house pipe and fixtures. The fresh-air vent should be carried to a considerable height and should not be immediately adjacent to any window, flue, or other orifice in the wall. From the mercury- seal by-pass the gas passes through a regular goose-neck meter connection he meter and from thence into the main riser of the house pipe, CHAPTER XV. CONSUMERS' METERS. Testing. All meters, when received from the factory, should be proved before being placed in service. The rating of consumers' meters, as to capacity, is three times its rated capacity of 6 cu. ft. of gas consumption per burner-hour; thus we have in a three-light meter about 3X3X6 = 54 cu. ft. per hour. In addition to the orig- inal test and such test as may be occasioned through complaints and contested bills, each meter should be tested whenever removed and brought to the shop and a record concerning such test be duly filed. Periodically these files should be gone over numerically and all meters which have not been tested within a period of 3 years should be brought to the shop and duly proved. It is good prac- tice to permit a meter to remain in the shops at least 12 hours before proving, in order that there may be an equalization of tem- perature. All meters showing a deviation by the prover-test of 2 per cent., either fast or slow, should be corrected or returned to the factory for repairs. Test each meter with gas to see that it registers with a very small consumption (called "check-test"); using a flame not larger than a dime, after which turn off the flame, leaving gas- pressure on meter; this is for detecting any holes in the dia- phragm or a leak in the valve. Then test for sticking or irregularity of flow by turning the gas on stronger until the flame should show two small horns. The best way to make this test is to have burners connected up on a header or stand of burners with sufficiently numerous outlets to work the meter to its full capacity. The third test is the regular one on the prover. When tests are made with the cover on the meter they should be for not less than two revolutions of the test-hand. When the cover is off a satis- factory test can be made with one revolution, this being made by both the "open" and "check" test. Meters showing a variance within 4 per cent, can generally be regulated in the shop, but for more than that amount it is good practice to return them to the factory. 209 210 AMERICAN GAS-ENGINEERING PRACTICE. In making the prover-test care should be taken that the water in the prover and the air in the room are at an identical tempera- ture. Make sure that the connections of the prover are perfectly tight, and then allow a cubic foot or more of air to pass through the meter, stopping with the pointer on the test-dial exactly at a divi- sion mark, then carefully adjust the pointer on the holder to zero, turn on the air to the meter and make one more complete revolu- tion of pointer on dial, stopping precisely at the point started from. The error corresponding to the discrepancy between the meter and the prover can then be calculated. Capacities. The following table is given by the gas educational trustees of the American Gaslight Association as the average capacity of the number of gas-meters resulting from a series of tests of several makes: CAPACITY OF GAS-METERS. Size Meter. Capacity in Cubic Feet per Hour with Loss of Pressure of & in. Capacity in Cubic Feet per Hour with Loss of Pressure of T 8 o in. 3-light 40 55 5-light 10-light 20-light 50 80 115 75 120 160 30-light 175 270 45-light 60-light 100-light .... 215 330 385 315 475 600 150-li?ht 300-light 1015 1635 It is important that all consumers' meters not in use should be carefully corked so as to make them air-tight in order to prevent the drying of the diaphragms. These corks should also remain in when the meters are shipped to the repair shops. Every consumer's meter, when set, should be carefully supported in position by a bracket, and in no case should it be allowed to hang on its own connections. Meters should be badged immediately when purchased and their identity established by recording them in a meter-record book or card system with index. This is of the utmost importance. In the case of a condemned meter, or one otherwise destroyed, a proper note should be made, embracing all details upon this register. In shipping meters back to the repair shop an invoice should be inclosed giving description of each meter and the reading of the CONSUMERS' METERS. 211 index. The returns made by the repair shop should be carefully preserved. Every meter should thus be accounted for either as set (as shown by route book and consumer's ledger), in stock, sent away for repairs, destroyed, or condemned. With the meter- badges on hand this should account for the whole number of badges. As a general rule all meters not being used should be removed and put in stock. Meter Connections. Meter connections should be made of uni- form length so that they will be interchangeable. They should not be too short, as they are then hard to bend without buckling. A good length for the smaller sizes is 12 in. and for the larger sizes 14 in., 16 in., and 18 in. When a meter is removed for an indefi- nite period the lead connections and cock should be removed and the service and riser capped or plugged. Meter connections should be made as follows: SIZE OF METER CONNECTIONS. Diameter of Diameter of Diameter of Siae Meter. Iron Pipe. Cock. Lead Pipe. Inch. Inch. Inch. 3-light a 2 5-light 3 10-light 1 1 1 Meters rated at 30 lights and over should be provided with screw connections instead of lead. Only standard connections FIG. 51. Iron Meter Connection. should be used and a set of hard-brass standard gages should be provided in every meter-shop. All new meters and unions should 212 AMERICAN GAS-ENGINEERING PRACTICE. immediately upon receipt from the factory be tested with these gages, and failing in standard should be rejected. The gage consists of two parts, a screw and a nut. The threads of the screw are exactly standard ; the countersink in the end of the screw is the diameter of the nose of the swivel. The nut is made to fit the standard screw exactly, and the hole in it is a gage for the swivel. The standard dimensions of unions for 3-, 5-, and 10- light meters are as follows: METER UNION STANDARDS. 3-light. 5-light. 10-light. Number of threads per inch 18 12 11* Diameter of screw inch 18 1|3 lt " swivel or nipple inch 5| 1* tl ll nose of swivel inch II 1 ? Frost and naphthalene can be removed from meters by pouring in the inlet a small quantity of wood alcohol or benzine. The process of injecting alcohol in a vaporized condition into the main, as described elsewhere by the writer, has an exceed- ingly beneficial effect upon the meters dia- FIG. 52. Test-meter. FIG. 53. Complaint Meter. phra;m and removing tar, naphthalene, and frost. Meter-readers should be prevented from using matches in read- ing meters; proper lanterns (Davy safety-lamp type) being sub- CONSUMERS' METERS. 213 MM* Atldrrts ^c"7 METER. /"3 to the use of pans of great depth for baking, their deep sides depriving the upper portion of their contents from its neces- sary quota of heat. It may, of course, be caused by defective con- struction of the oven, which in this day of gas-range competition is extremely unusual. Defective regulation, insufficient insulation of the oven-bottom, etc., may also be contributory causes. Care should be taken that all the drilled holes in the burners are clear and free from stoppage and that the flame produced is of a proper 254 AMERICAN GAS-ENGINEERING PRACTICE. color and forms with the air-mixture a jet in the shape of a per- fectly symmetrical cone. There is no economy in placing food in the oven before it attains the proper heat, which under usual conditions is approximately four minutes. This period of prepara- tion permits the walls and linings of the range to heat up and the atmosphere of the range to obtain the temperature requisite to efficient service. This is especially necessary with a gas-range, because the intense heat is localized immediately beneath the oven, usually within 3 in. under the bottom of the bread, whereas, with the ordinary coal-range, the oven is more or less insulated from direct heat, but is heated by the products of combustion, all parts equally and practically simultaneously. In extreme cases a covered baking-pan with a ventilator may be used; this ventilator should remain closed until the bread is nearly baked. This cover should be removed at from two to three minutes before taking the bread from the oven, which period is usually sufficient to properly brown it. During this final period the heat should be increased to the maximum capacity of the burner. The rule, to preheat the oven, should be invariable, and it is usually best to accomplish this by using the maximum capacity of the oven-burner, after which the flames may be somewhat reduced until a slow, even heat is secured. As before mentioned, the tem- perature is again increased to maximum during the "browning" period. The temperature necessary in ovens, of course, varies directly with the food to be cooked, pastries, etc., requiring intense quick heat, while other food requires slow, even temperature. Gas-ranges when leaving the factory are generally regulated for the average pressure in the town in which they are to be in- stalled. In every town, however, the district or local pressure varies widely. It is occasionally necessary to change this rating on the part of the range, which is done either by supplying a dif- ferent nozzle or tip, these being furnished by the range-makers and located in the gas-inlet of the burner. Gas-ranges cannot be expected to operate efficiently under a greater variation than that of 1.8 to 3.5 in., 2 to 2.5 in. obtaining the highest efficiency. Should the district pressure vary between greater limits than these, a proper governor should be placed either upon the house service or directly before entering the gas-range itself. Essentials. A few of the essentials to be observed in the selection of a gas-range by any gas company are: 1. Removable burners to facilitate cleaning. 2. Snugly fitting air-shutters, convenient to adjust and fitted with set-screws to retain the adjustment. APPLIANCES. 255 3. Removable linings for facilitating repairing. 4. Sufficient weight of castings to prevent breakage in mov- ing and mechanical strength, such as unusual strength on the part of hinges, brackets, and all castings subject to strain. 5. Distribution of heat in the oven. 6. Properly set burners, their position being located so as to obtain the highest efficiency in combustion. 7. Oven-burners, evenly drilled, distributing the flame in equal cones and low enough not to impinge the flame upon the baffles or heat-distributors over the bottoms. 8. Sufficient flue-opening to prevent smothering the burners, to remove aqueous vapors from the oven, and to furnish ventilation for steam. 9. Sufficient air-ports to supply ventilation to the above flues. 10. Linings of sufficient thickness, say not less than 22 or 24 B. & S. gage, so as to prevent rusting out in a reasonable length of time. 11. Proper construction of top burner to prevent leakage in cemented joints. The quantity of heat lost by radiation in gas-ranges will aver- age 20 to 25 per cent. Combustion. The drilled burner has now been almost uni- versally adopted. The size of drill-holes for an average illuminat- ing-gas of 2-in. pressure will average for the top burners (single burners) ^ in. diameter. For the top burners (double) ^g- in., except in the case of double top burners with two valves, which have drilled holes of ^ in.; even burners having two valves will average -^ in. diameter holes. The following excellent description of the inductor or aspirator in a gas-burner is given by P. A. Degener. The action of the inductor of an atmospheric gas-burner depends upon the friction of the moving stream of gas which draws in air around it, the kinetic energy of the gas giving power to bring the mixture to the outlet of the burner. The two essential points are: to com- bine the velocity and force of the gas-jet with the largest possible surface, and shape the inductive body in such a way that the in- coming air will be forced against the jet. Qas=range Cocks. Where the range cock is used it should in- variably be of the lock -wing removable-handle, socket-head type in order to insure the proper control of this valve and to prevent its use by children or ignorant persons. It is a matter of history that ninety per cent, of the gas-range accidents which have occurred have been through a meddling with 256 AMERICAN GAS-ENGINEERING PRACTICE. or improper use of this cock, with the result that its service has been abandoned by at least half of the gas companies of this country. After gas-ranges are set they should be inspected thoroughly by a competent inspector, who will note pressure, adjustment, and me- chanical correctness of fittings, and who should then instruct the consumer in the use of the appliance. As it may occasionally be necessary to set the gas-ranges or gas- burning appliance in districts where the pressure is abnormally low or subject to very considerable fluctuation, having a low minimum sawed burner will be found to be advantageous, as it is less liable to iiash back under sudden drops of either pressure or candle-power. The quality of gas most efficient for the use of gas-ranges and other gas-burner appliances depends entirely upon its calorific value, which varies in the case of coal-gas, straight water-gas, or mixed gas. The gas should have, however, a value of about 650 B.t.u., and should not be less than a minimum of 16 to 17 candles; for coal-gas 18 candles are better, 20 candles for water-gas, and 18 candles for mixed gas (see table of candle-power compared with calorific value). The most satisfactory results from water-gas, however, are obtained from a 22-c.p. gas; with this gas, while it is possible to adjust aBunsen mixture at 1.5 in. pressure, the most satisfactory results obtain under 2.5 in. pressure, the maximum permissible being about 3.5 in. Where ranges or other heating appliances are used adjacent to walls, such walls should be invariably protected by sheet asbestos- board. Testing Ranges. As has been said, under very widely varying pressure conditions, or rather under conditions of extreme high or low pressure, where local governors may be deemed inadvisable, it may sometimes be best to vary the size of the nozzle used on the gas-inlet to the Bunsen burners. These nozzles are bored or drilled according to the B. & S. or Morse standard drill gages, and to test or identify their sizes, which run usually between 30 and 45, an internal-diameter gage is used, as shown in Fig. 63, opposite. It should always be among the tools of every fuel-appliance or repair department. An examination into the standards for gas-ranges maintained by the largest fuel-supplying companies of this country shows about the following average: The floor test, which is made by placing a black-bulb chemical thermometer upon the floor immediately beneath the oven and just below the center of the range, should show a mean tempera- ture of about 120 deg. Fah. in 40 minutes after lighting. It is necessary that a black-bulb thermometer be used in order to prevent the reflection of radiant heat. APPLIANCES. 257 It is presumed that a gas-range oven of ordinarily good con- struction will attain a baking heat, viz., about 400 deg. Fah., with 650 B.t.u. gas in from 9 to 11 minutes (pressure from 1.5 to 2.0 in.). The consumption of gas during this period of time (i.e., 10 minutes) varies from 4.5 cu. ft. with air-jacketed, sheet-iron ranges to 11 cu. ft. with "all cast-iron type." Very few makes of ranges, from a standpoint of efficiency, show identical results, those of low efficiency being sometimes com- pensated to some extent by points of durability, strength, etc. Bottom of Qauge FIG. 63. Gage for Burner-holes. The oven test is made by perforating the side of the oven and inserting a 700-deg. Fah. straight-tube thermometer through an asbestos saddle. The saddle should shield the thermometer from contact with the case of the range, and the saddle and thermometer when inserted should completely close the orifice. Range-ovens should be so constructed and ventilated that they will become evenly heated in all parts after the burners have been lighted for ten minutes. Both top and bottom of any food baked should be evenly browned and upper and lower racks should show uniform results and identical heat. Moreover, the center of the oven should show no different results from its extreme edges, a test for even heat throughout the oven being best effected by placing small pieces of unglazed paper of equal size in various portions of the oven and noting the degree of equality with which they are browned. 258 AMERICAN GAS-ENGINEERING PRACTICE. The floor temperature test should never indicate a higher heat than 1100 deg. Fah., as any increase over this may become danger- ous to woodwork. A number of companies specify an air-space of not less than 1 inch in the bottom construction of the oven, and that there be not less than 3 inches of clear air-space between the bottom of the range and the floor. This arrangement gives practically no floor temperature at all and should produce an oven of high efficiency. Where asbestos sheets are used, the construction should be such (see Fig. 64) as to permit their being readily interchanged. oooooooooo I < > u t_ Asbestos Asbestos FIG. 64. Asbestos Gas-range Lining. A simple test for determining whether a range oven is ready for baking consists in placing an ordinary piece of white writing-paper upon the lower shelf; in the case of bread it should turn dark brown quickly; for cake it should turn golden brown when placed upon the middle shelf. Demonstrators should be urged to, as far as possible, instruct consumers in the method of boiling, broiling, etc., within the oven instead of upon the upper burners. It is possible, in fact, to exe- cute any manner of cooking within the oven which can be done upon the top burners, and usually much more efficiently and with better culinary result. Demonstrators and canvassers should also urge upon the consumer the absolute necessity of cleanliness in the maintenance of a range, both for the preservation of the appliance and the obtaining of efficient results. The range should be washed at least twice a month with a stiff brush and afterwards by a cloth with warm water and a little caustic APPLIANCES. 259 soda. The casting should be gone over while the parts are still warm. All loose parts, including racks, burners, and any small or movable portion of the range, should be placed within the soda water and permitted to soak, after which the whole should be wiped off with a soft clean cloth and the burners lighted for a few mo- ments after reassembling to dissipate any possible dampness and prevent rust. The whole should then be gone over and carefully oiled with a rag containing machine-oil. This will prevent rust and is infinitely preferable to any form of stove-polish. A set of specifications gotten out by one of the leading gas engineers is herewith appended. Range Specifications. The weight of a 16-in. range complete shall not be less than 150 Ibs.; that of an 18-in. range not less than 175 Ibs. Top Burners, To consist of three single, one giant, and one simmer burner. Giant burner to be the left- hand front burner. Simmer burner to be lo- hed cated back of the front burners and not inside of any of the burners. To be separable with a good depth of bowl, with a well-fitting joint, construction as shown on accompanying drawing preferred. All burn- FIG. 64. Gas-range ers to be so placed that they can be lifted out; Top Burner, no bolts to be used. Carrying-tube. Top burners to be open on the mixer end to admit brush for cleaning. Mixer to have adjustable shields that can be made rigid when required. Top and Oven Mantles. To be extra heavy f-in. pipe through- out. Gage of Metal. In the body and linings of the stove to be No. 24. Body of Stove. To have dead air-space not less than J in. asbestos-lined. Pipe-collar. To take 4-in. pipe, and to be located on rear of range top. Oven Flame-plate. The oven flame-plate and bottom should be of not less than 20-gage metal with center braces. (See Fig. 61.) This flame-plate construction is preferred. Oven-burners. To be two long drilled burners, open at mixer, and to admit brush for cleaning. Pilot-light. To be so constructed that it will light both oven- burners, and the flame to be visible from the outside of the oven. Valves. Ranges to have "needle-valves having independent adjustable apertures with needle-point heads that can be easily 260 AMERICAN GAS-ENGINEERING PRACTICE. moved with fingers for the purpose of properly adjusting the gas supply. Needle-point heads to be covered by suitable caps. Gas Supply to Top Burners. To be taken off manifold at back before supply is taken for oven-burners. Gas supply to all burners should rise. Not less than 3 in. of clear air-space to be provided between bottom of range and floor. Doors. To be drop pattern balanced by counterweight; no catch or spring to be used. Gas Apertures. To be drilled to allow a consumption by oven- burner of 27 cu. ft. each. Single-top burners to be 12 cu. ft. capacity, giant burners 18 cu. ft., water-heater burners 40 cu. ft., measured at a gas pressure of 1.2 in. B. LIGHTING APPLIANCES. Mantle Burners. Incandescent gaslights increase in candle- power in direct ratio with the pressure of the gas flow, and it is the experience of the writer that they cannot be successfully operated under less pressure than 1.8 in. of water. There are many makes of these lights, the best of which should comply with the following specifications: First. That both the air-inlet and gas-inlet be capable of easy and complete regulation. Second. That the parts be as nearly as possible interchange- able. Third. That the mantles burn with an even light throughout their entire service, and be of satisfactory longevity, in which latter respect the aluminum-type mantle seems to take preference over those supported by asbestos. The gas-apertures in the regulating-valves of these burners are exceedingly small and easily clogged. It should therefore be a cardinal rule with all gas companies that their workmen should carefully examine the condition of the fixtures before installing a burner or replacing a mantle, and that this examination should reveal a clear, unimpeded flow of gas with full pressure and free- dom from obstructions, this latter being caused, as a rule, by con- densation in the pipes, meter, or services, and which can generally be removed by the sudden admission of compressed air from a pump to the proper condensing-chamber. Candle=power and Heat Value. In a lecture delivered be- for the Institution of Gas Engineers, Prof. V. B. Lewes gave the following table as the average relation between candle-power and calorific value as determined by a number of tests, but said that the results in any particular case might vary 5 per cent, either way from these, and even with this qualification exception was APPLIANCES. 261 taken to the figures by gome gas engineers. They stand, how- ever, as the most definite statement yet published. Calorific Value, B.t.u. per Cubic Foot. Candle-power. Coal-gas. Carburetted Water-gas. Gross. Net. Gross. Net. 12 540 480 490 452 13 560 500 510 472 14 585 522 529 489 15 610 542 547 508 16 625 562 567 527 17 647 582 587 547 IS 670 603 607 567 19 690 622 627 587 20 712 642 647 607 As a result of work done in the University of Michigan, Messrs. White, Russell, and Traver decided that, all other conditions being the same, the light given per cubic foot of gas, when consumed in incandescent burners, was proportionate to the calorific value of the gas, and increased directly at the rate of one candle per each additional four calories (or 15.87 B.t.u.). With these experiments the ordinary C. Welsbach burner, with Welsbach mantles, was used, the air and gas adjustment of the burner being such as to obtain the maximum of light. Prof. V. B. Lewes claims, however, that the efficiency of the gas in an incandescent burner depends more upon the flame temperature than upon the calorific value, and cites results of certain experiments, showing a duty of from 19 to 20 candles per cubic foot from blue water-gas when burned in a certain design of Argand burner without any preadmixture of air. The mantle itself never attains the theoretical, or even the actual, temperature of the flame, so for all practical purposes the efficiency of illuminating-gas for use in incandescent burners may be stated as being directly proportional to the calorific value. By the calorific or heat value of a fuel is meant the total number of heat-units which may be developed from it by complete combus- tion, the comparison being per cubic foot. The calorific value of an elementary substance can only be obtained by experiment, but that of compounds is simply calculated by an addition of the sum of the known heat value of their constituents. Caloric Requirements for Incandescent Lighting. Man- tles can be made to give their full lighting power with low 262 AMERICAN GAS-ENGINEERING PRACTICE. heat-unit gas, such as blue water-gas, which runs as low as 290 B.t.u. per cubic foot. With 350 B.t.u. blue gas a first-class 80- candle-power Welsbach burner will give its full lighting power on 6J feet of gas. There is always a peculiarity to be noted in the case of blue gases, such, as was found with the 80-c.p. burner just cited. The ordinary American Welsbach No. 71 burner consumes about 4 cubic feet of 600 B.t.u. gas to give its full lighting power. This same burner, which should theoretically burn 7 to 8 cubic feet of 300 B.t.u. gas to give the same effect, burns only about 6^ to 6^ feet to do so. In other words, the efficiency of the blue gas relative to its heating power is greater than that of ordinary illuminating-gas. Flat=flame Burners. The principles governing the efficient combustion of gas for the direct production of light are very fully set forth in King's "Treatise on Coal-gas," from which the following summary has been taken: "Since the light given by a gas-flame is due principally to the raising to incandescence of particles of carbon set free by reactions occurring in the flame, to obtain the maximum amount of light it is necessary that the gas should be so consumed as to secure the setting free in the flame of the greatest possible number of carbon particles and the raising of the particles to the highest possible temperature. These two conditions can only be secured by the proper regulation of the amount of air supplied to the gas-producing flame, and of the manner in which the air is brought into contact with the gas. The formation of the carbon particles being due to decomposition of the hydrocarbon constitu- ents of the gas, principally by effect of heat, anything which tends to cause the combustion of these hydrocarbons before they are sufficiently heated to be decomposed reduces the amount of light given by the flame by reducing the number of carbon particles present in it. And since the amount of light produced by any given number of carbon particles increases with the temperature to which they are raised, anything that tends to lower the temperature of the flame also reduced the amount of light given by it. "Any admixture or intermingling of air and gas reduces the illuminating power, both by partially consuming the hydrocarbons before they are sufficiently heated to be decomposed, and so reducing the number of carbon particles in the flame, ar.d also by cooling the flame. Any over-draught by which an excess of air is brought into contact with the flame so as to be heated by it reduces the illumi- nating power by cooling the flame. To secure the maximum amount of light from the gas, it is therefore necessary that the air should be brought into contact with the gas in just the proper amount required for its complete combustion, and in such a way that the contact takes place only on the surface of the flame. With APPLIANCES. 263 flat flames the great cause of intermingling of air and gas and of excess rush of air against the surface of the flame is a high velocity of exit of the gas from the burner-tip into the atmosphere. The velocity of exit increases rapidly with the pressure at which the gas is supplied to the burner-tip. It is therefore essential that the pressure at the tip be low. With an Argand burner this pressure can be reduced to practically nothing, but with flat-flame burners a certain amount of pressure is necessary to develop the flame to its proper shape, this being especially the case with union jet (fish- tail) burners. " Any swirling motion in the gas also tends to produce an inter- mingling of gas and air as well as a disagreeable noise, and therefore the arrangement of the burner should be such as to supply the gas to the points of ignition in an even flow free from eddies or rotary motion. To insure that all the gas shall be consumed to the best advantage, it is necessary that the proper proportions between the gas and air supply shall exist over the whole surface of the flame, and therefore that the gas shall be supplied in equal quantity at all the points of ignition. "The following details of construction have been adopted to put into effect the principles brought out above. To insure the existence of a low pressure at the burner-tip the improved forms of flat-flame burners are provided either with some forms of governor, which maintains the pressure at the tip constantly at the proper point, no matter how much the pressure on the piping increases, or else with a ' check/ which is usually a metal, steatite, or lava disk inserted in the burner pillar so as to cut off any flow of gas to the tip except through a hole in the disk, the area of which is smaller than that of the opening in the tip, the relation between the area of the opening in the check and that of the opening in the tip varying with the pressure at which the burner is designed to be used, that is, the higher the pressure the smaller the hole in the check for same-sized tip. "To produce a steady, even flow of gas without any swirling motion, some burners have placed between the check and the tip a screen of fine wire gauze, which breaks up any currents and ren- ders the flow of gas uniform throughout the whole area of the burner pillar, while others depend upon the steadying action pro- duced by the large area of the burner pillar above the check as compared with the area of the opening in the tip. "To secure an equal supply of gas to all parts of the flame, slit (batswing) burners are made with what is called a hollow top, by means of which the slit is kept at the same depth in all parts instead of being much thicker at the top than at the sides, as it would necessarily be if the top of the tip were left solid instead of hollowed 264 AMERICAN GAS-ENGINEERING PRACTICE. out inside to conform with its shape outside. The effect of extra thickness at any place is that less gas passes through the slit at the thick place, and that consequently the conditions are not the same at all parts of the flame. A further improvement in this direction, introduced in some burners, consists in cutting the slit with a cir- cular saw applied from above the tip, and thus making it curved on the bottom instead of flat, as is the case when it is cut by sawing in the ordinary way. With the flat-bottom slit some of the gas issues at right angles to the axis of the burner, only to be folded back on the upper part of the flame by the upward draught of air caused by the heat of the flame, while with a curved-bottom slit this effect is avoided, as the gas issues in a direction along which it is free to travel without being turned aside, and the flame is thus kept of more even thickness throughout. "In Snugg's table-top burners the effect of the upward rush of air in increasing the thickness of the lower edges of the flame is still further guarded against by forming a circular ' table' immediately under the top of the tip, the projection of which deflects the cur- rents of air and prevents them from rising vertically against the flame." C. INDUSTRIAL APPLIANCES. Operation. For gas-furnaces and industrial appliances the air pressure should have a minimum of one pound and a maximum of two. The exact air pressure, of course, depends upon the ther- mal quality of the gas, it being necessary to obtain the exact ratio between the two for complete combustion. Flashing back in all forms of Bunsen burners is caused by the flame traveling back through the burner to the issuing gas-jet and may be due to insufficient velocity of exit at the burner-head of the gas-air mixture, to a too highly heated burner-head, to the exit orifices of the burner-head being too small, to the mixing-tube being too hot, etc.; it may be overcome by increase of gas pres- sure or the removal of the mixer to a further distance from the heat area. It is sometimes caused by the faulty design of the burner, but in practice more often by the clogging of the burner or air-hole strainer, thereby reducing the gas velocity, as before mentioned. It is occasionally remedied by the intervention of one or more wire screens between the head of the burner and the air- intake. This acts on the principle of the Davy lamp, reducing the temperature of the gas to below the combustion-point. An angle bend or deflection in the pipe intervening between the air-mixture and burner outlet tends to prevent flashing back, which fact is utilized in the construction of the Martin incandescent burner. A test made by the Troy Laundry Machine Co. shows a saving APPLIANCES. 265 of one-half of the gas consumed by admission of air to Bunsen burners under pressure, as against the use of atmospheric burners. The minimum pressure of gas for gas-arcs should never be less than 2 in., 3 in. being good average. The maximum of low-pres- sure efficiency is usually obtained at about 4.5 in. ; but under high- pressure conditions the result obtained at one pound per sq. in. pressure practically doubles the efficiency of the appliance. Where air is admitted to Bunsen burners under considerable pressure and the gas and air are brought together at the burner, there is a chance, due usually to some stoppage in the burner, of the air backing up into the meter and forming there an explosive mixture. To prevent this, it is a safeguard to place a free-swing- ing check-valve on installations of this kind between the burner and the meter. The writer's tests of efficiency of burners under stereotyping crucibles and linotype machines vary between 60 and 70 per cent. The complete combustion, of course, depends upon the chemical constituents of the gas; it will run, however, between two and three times the gas volume in general practice. The Bunsen mixture or complete combustion of gas through the preadmixing of air is best observed by its gradation in color. The pure gas burns a yellow flame; the preadmixture of air is indicated by a blue cone, an increase of air showing green, which in excess shades down almost to the white of an alcohol flame, high economy in the admixture, continuing the air addition, stopping just short of the flashing-back point. The writer's data show the highest record of flame tempera- ture obtained from a Bunsen flame to be 1950 to 2000 C. Consumption. The consumption of burners used in various industrial furnaces and processes has been found to be as follows : Appliances. Average Consumption, Cu. Ft. per Yr. Appliances. Average Consumption, Cu. Ft. per Yr. Rivet-heaters 300,000 Braziers 75000 Meat-branding machine. 150,000 Caldron heaters 120 000 Hotel range 300,000 Soldering furnaces 40000 Tinning-bath. 300 000 Gas-arc lamps 24 000 Linotype machine Gas forges 50,000 300,000 Tailor- iron heaters Laundry irons 40,000 18000 Gas bakery ovens 200,000 Gas manglers 50000 Gas steam-tables Enameling ovens 200,000 120 000 Glue pots Water-stills 40,000 Qf) ooo Confectioners' gas- Gas broilers. . . 50000 stoves 120,000 Incubators. . . . 10000 Popcorn poppers and peanut roasters 50,000 Gas-engines per actual working h.p 60000 266 AMERICAN GAS-ENGINEERING PRACTICE. Qas=engines. In order to find the size of meter required for a gas-engine, multiply the brake horse-power by 3.4+5 for the num- ber of lights of meter. Exhaust-pipe. From 1 to 5 horse-power requires a 1-in. to IJ-in. pipe; above that size the diameter of the pipe should equal D =0.528 h.p.- 57 , or about 0.528Xthe square root of the horse- power. The heat of the exhaust-pipe is great and likely to burn wood if too near. Bends of 6 in. diam. or more should be used and no elbows or T's allowed. Turn the outlet of the pipe to look downward. To prevent excessive noise, the pipe can be carried into a drain-pit and surrounded with stones covered over with straw. Cooling-water. About 5 gallons of water per horse-power per hour will be required for the cylinder if the water be taken direct from the main. If hard water is used, a handful of washing-soda should be used in the tank every month. Circulating-tank. About 20 or 30 gallons per h.p. of cooling- water with pipes from 1 to 3 in. diam. are necessary. The return- pipe is usually a little larger than the flow, with a rise of at least 2 in. per foot leading to the tank at the normal water-level. PART III. GENERAL TECHNICAL DATA. CHAPTER XIX. PROPERTIES OF GASES. A. Composition. B. Volume. C. Specific Gravity. D. Specific Heat. E. Calorific Value. F. Temperatures. G. Heat Data. A. COMPOSITION OF GASES. Various Gases. The following table is given by Bates as the average percentage constitution of the gases named. AVERAGE COMPOSITION OF GAS (PER CENT). Gases. CO 2 O CO N C 2 H 4 CH 4 H Flue gas (bituminous coal). Hoffman coke-oven gas. . Producer-gas (bitumi- nous coal) 9.65 1.41 2.05 8.55 0.43 0.30 0.00 6.49 27.00 81.80 0.00 55.30 0.00 2.04 0.40 0.00 36.31 2.50 0.00 33.32 12 00 Producer-gas (anthracite coal) 2 50 30 27 00 57 00 00 1 20 12 00 Water-gas 4 00 50 45 00 2 00 00 3 50 45 00 Natural gas 00 80 60 3 00 1 00 72 00 22 00 Coal-gas. . 0.30 0.40 0.60 2 80 4 30 36 50 48 10 268 AMERICAN GAS-ENGINEERING PRACTICE The following table is credited to J. M. Morehead. APPROXIMATE COMPOSITION OF ORDINARY GASES. 4 g 9 . *i Gas. 3 o.o I 1 -aj | o jj 1 n 5 1 i o >> n 1 2 PQ Water-gas 24 c.p. . . 4.5 13.0 0.5 29.0 32.0 16.0 5.0 720 0.63 Coal-gas 16 c.p. . . . 2.0 5.5 0.5 11.5 43.5 35.0 2.0 610 0.45 Acetylene (commer- cial) 96 1 4 1600 92 Flue gas 16.0 4.5 0.5 79.0 1.06 Pintsch gas 0.5 23.5 0.5 1.0 18.5 52.5 3.5 1100 0.73 Engine exhaust. . . . 8.0 17.0 75.0 1.04 Producer-gas Natural gas 6.0 2 27 1 22.0 1 11.6 3.6 88 1 58.0 5 2 150 900 0.89 56 Blue water-gas. 3 43 25 50 5 3 25 350 42 20 7 79.3 1.00 The above figures are given as an average of those which ordi- narily obtain in the best practice. Local conditions and require- ments probably will, of course, vary these figures in individual instances. Properties. Another authority compiles the following char- acteristics of gases usually met with in metallurgical calculations. CARBONIC ACID OR CARBON DIOXIDE. Formula CO 2 Composition by weight 73 . 7% O, 27 . 3% C Density or specific gravity, air= 1 1 . 529 Lbs. per cubic foot .116 Cubic feet per Ib 8 . 62 Cubic feet air necessary to consume 1 cu. ft Non-cumbustible B.t.u. per cubic foot Non-combustible Solubility : Vols. absorbed in 1 vol. water 1 .23 ILLUMINANTS OR HEAVY HYDROCARBONS. Formula 90% C H 4 Composition by weight 85.7% C, 14.3% H Density or specific gravity, air= 1 . 985 Lbs. per cubic foot . 074 Cubic feet per Ib 13 . 38 Cubic feet air necessary to consume 1 cu. ft 14.34 B.t.u. per cubic foot 1675 Solubility: Vols. absorbed in 1 vol. water .15 PROPERTIES OF GASES. 269 OXYGEN. Formula Composition by weight 100% O Density or specific gravity, air= 1 1 . 105 Lbs. per cubic foot .084 Cubic feet per Ib 11 . 94 Cubic feet air necessary to consume 1 cu. ft Non-combustible B.t.u. per cubic foot Non-combustible Solubility: Vols. absorbed in 1 vol. water .028 CARBONIC OXIDE OR CARBON MONOXIDE. Formula CO Composition by weight 42.9% C, 57. 1% O Density or specific gravity, air = 1 .967 Lbs. per cubic foot .073 Cubic feet per Ib 13 . 57 Cubic feet air necessary to consume 1 cu. ft 2.39 B.t.u. per cubic foot 341 Solubility: Vols. absorbed in 1 vol. water.. .023 HYDROGEN. Formula H Composition by weight 100% H Density or specific gravity, air= 1 .069 Lbs. per cubic foot .006 Cubic feet Ibs 189 . 23 Cubic feet air necessary to consume 1 cu. ft 2.39 B.t.u. per cubic foot 345 Solubility: Vols. absorbed in 1 vol. water .019 METHANE OR MARSH GAS. Formula CH 4 Composition by weight 75% C, 25% H Density or specific gravity, air= 1 . 556 Lbs. per cubic foot .0422 Cubic feet per Ib . 23 . 72 Cubic feet air necessary to consume 1 cu. ft 9 . 56 B.t.u. per cubic foot 1065 Solubility: Vols. absorbed in 1 vol. water .035 NITROGEN. Formula N Composition by weight 100% N Density or specific gravity, air= 1 .971 Lbs. per cubic foot .073 Cubic feet per Ib 13 . 57 Cubic feet of ah* necessary to consume 1 cu. ft Non-combustible B.t.u. per cubic foot Non-combustible, Solubility: Vols. absorbed in 1 vol. water ,,,.,, .01 270 AMERICAN GAS-ENGINEERING PRACTICE. ACETYLENE. Formula C 2 H 2 Composition by weight 93 . 3% C, 7.7% H Density or specific gravity, air = 1 . 918 Lbs. per cubic foot . 069 Cubic feet per Ib 14 . 32 Cubic feet air necessary to consume 1 cu. ft 11 .91 B.t.u. per cubic foot 1600 Solubility: Vols. absorbed in 1 vol. water 1.11 AIR. Formula Mixture O and N Composition by weight. 77% N, 23% O Density or specific gravity, air= 1 1 .000 Lbs. per cubic foot . 076 Cubic feet per Ib 13.15 Cubic feet air necessary to consume 1 cu. ft. . Non-combustible B.t.u. per cubic foot Non-combustible Solubility: Vols. absorbed in 1 vol. water .017 SPECIFIC GRAVITY, WEIGHT, AND SOLUBILITY IN WATER OF VARIOUS GASES AT 60 FAHR. AND 80 IN. BAROMETER. Name. Hydrogen Light carburetted hydrogen Ammonia Carbonic oxide Olefiant gas Nitrogen Air Nitric oxide Oxygen Sulphureted hydrogen . Nitrous oxide Carbonic acid Sulphurous acid Chlorine Bisulphide of carbon. . . Specific Gravity, Air Equal 1.000. 0.0691 0.559 0.590 0.967 0.968 0.9713 .000 .039 .1056 .1747 .527 .529 2.247 2.470 2.640 Weight of a Cu. Ft. in Pounds Avoir. 0.00529997 0.0428753 0.045253 0.0741689 0.0742456 0.07449871 0.0767 0.0796913 0.08479952 0.0900994i, 0.1171209 0.1172743 0.1723449 0.189449 0.202488 Weight of a Cu. Ft. in Grains. 37.09 300.12 316.77 519.18 519.71 521.49 536.60 557 . 83 593.59 630.69 819.84 820.92 1206.41 1326.14 1417.41 Number of Cu.Ft. Equal to 1 Ib. 188.68 23.32 22.09 13.48 13.46 13.42 13.03 12.54 11.79 11.09 8.53 8.52 5.80 5.27 4.93 Solubility. 100 Vols. of Water Absorbed. 1.93 vols 3.91 " 72,720 2.43 " 16.15 " 1.48 " 1.70 " Not soluble 2.99 vols 323.26 " 77.78 " 100.20 " 4276.60 " 236.80 " Not soluble PROPERTIES OF GASES. 271 B. VOLUME OF GASES. Expansion of Gases. According to Professor Lineham, " two laws govern the varying volume of a gas, according to whether temperature or pressure be kept constant. The first law of gas expansion, discovered by Boyle in 1662 and verified by Marriotte in 1676, states that the volume of a given portion of gas varies in- versely as its pressure if the temperature be constant. Shown by symbols, V varies as -^ and PV= a constant. The relation of P and V is shown by diagram in Fig. 66, the ordinates PP f of the curve representing pressure and the ab- scissaB VV corresponding volumes, a temperature t being main- VOLUMES FIG. 66. Relation of Volume to Pressure. tained. Only one curve, the rectangular hyperbola, has ordinate X abscissa constant throughout, and that is the form of the curve AB. Although always approaching the co-ordinates OC, OD, it only meets them at infinity. Isothermals. By reason of equality of temperature, AB is also known as the isothermal of a perfect gas, that is, of a gas fol- lowing Boyle's law perfectly. Marriotte's tubes, Fig. 67, prove fairly well the accuracy of this law. A and B are strong glass tubes, A being sealed at top, level with mark 10, and C is a stout though flexible rubber tube. Taking the first position, mercury is poured into the funnel D until about level with 0, and a final adjustment made by moving B up and down. A portion of air, imprisoned in the leg A, supports a pressure of one atmosphere, D being open, and has the volume of 10 in. Raise B until the mercury reaches 35", and the fluid in A will have risen to 5". The difference of mercury levels is now 30 in., representing an additional pressure of one atmosphere; so the air 272 AMERICAN GAS-ENGINEERING PRACTICE. now supports two atmospheres and has a volume of 5 in., or PXV is constant. Intermediate experiments can easily be ob- tained and the law more generally proved. The so-called per- manent gases are practically perfect, and others fairly so, if meas- ured at a much higher temperature than that of liquefaction. The second law of gas expansion was discovered by Charles in 7 Je J - i 6 1 3 ,W "ft ' JL A 1 i 11 - \ I 3 if / / \ v. c, J ^ ' / 32 ... o FIG. 67. Apparatus Illustrating Boyle's Law. FIG. 68. Relation of Volume to Temperature. 1787, published by Dalton in 1801, and by Gay-Lussac in 1802, all independently. The last-named completely verified the law, which states that the increase in volume of a given portion of gas varies directly as the increasing temperature, if the pressure be constant; or, if Fbe original volume, V\ the increase, V 2 the total volume after increase, and t the rise in temperature. varies as t and Vat, PROPERTIES OF GASES. 273 a being the coefficient of cubical expansion. V and a are constant and t the only variable; hence The coefficients of linear expansion for solids vary with the substance, as do also their cubical coefficients (being three times the linear ones); but all gases not only expand regularly, but each to the same amount, increase of temperature being equal, one coefficient serving for all. Between 32 and 212 the total expan- n *^\fi^ sion is 0.3665F or =0.00204 for each degree: figures found loU by Gay-Lussac, expanding the air in an air-thermometer, the bulb dipping in heated water, whose temperature was taken by mercury- thermometer. Absolute Zero of Temperature. Let AB, Fig. 68, be an air- thermometer with an air-tight piston C, and the volume AC be called 1, the temperature being 32. Set off ordinate CD for vol- ume at 32, and FE for that of 212. The latter will be 1.3665, and the gradual volumetric increase be shown by the straight line DE. Supposing the law true for extreme limits, -line DA (a pro- duction of DE} will mark out the volume as we decrease the tem- perature, ultimately meeting AB in A. Then at A the volume will have decreased to nothing, and all the heat will have been taken out of the air. Though these possibilities are absurd, their supposition enables us to fix a zero-point having important advan- tages in thermo- volumetric calculations. To find A, the absolute zero of temperature, we proceed by similar triangles : AC DG DGXCD 180X1 CD=GE and AC= Tffl = = 492 ab Ut > then A's reading = 492- 32 =460 below zero F. Any ordinary temperature F. may, then, be made absolute by adding 460, and while t indicated Fahrenheit readings, r will show absolute readings. Note that Fig. 68 is a graphic statement of Charles' law, AE being an isopiestic or line of constant pressure, and AB a line of constant temperature. Combination of Boyle's and Charles' Laws. PV is invari- able for any particular position on the thermometric scale; but 274 AMERICAN GAS-ENGINEERING PRACTICE. if t be raised, the value of PV will be raised also. In Fig. 68, if P be kept constant, v will vary as i; so if V increases at the same rate as t, any series of multiples of V will similarly increase; and as P would be such a multiplier in Fig. 68, then PV varies as t and PV=ct, which is strictly general, c being a coefficient depending on the gas. Taking one pound of air at a temperature of 32, and at atmos- pheric pressure, reckoning in Ibs. per sq. ft. and in cubic feet, Regnault found by experiment that PV= 26,214= ct, then c= For superheated steam c=85.5. The above formula gives P or V at any temperature, when c is known. Three States of Matter. These, the solid, liquid, and gaseous, are well understood, and it is also now admitted that all bodies are capable of existence in each case successively, though not necessarily at the normal pressure and temperature. Taking one pound of any substance and applying the specific heat due to its state, its temperature rises one degree, and as the specific heat is approximately regular for each state, practically the whole heat is registered on the thermometer. But in all substances two crit- ical points occur, called the points of fusion and evaporation, and known respectively in case of water as the 'freezing- and boiling- points*; at these points additional heat is absorbed merely to do the work of rearranging the molecules, of fusing or melting on the one hand and of evaporating on the other hand. Such 'latent' heat is not observable on the thermometer and must, therefore, be otherwise detected." SOME OF THE MORE COMMON GASES. Gas. Sym- bol. Molec- ular Weight. Gas. Sym- bol. Molec- ular Weight. A 'a NHs 17 Nitrogen No 28 At h " " a' N 9 O 44 Br 2 160 Nitric oxide NO 30 Clo 71 Nitrous anhydride. N 9 O-< 76 CO 28 Nitric peroxide NO 2 46 CO 2 44 N 2 O 4 92 Ethylene CoH* 28 32 Ha 2 Sulphureted hydrogen . . . TT 34 Hydrogen chloride HC1 I 2 36.5 254 Sulphurous anhydride. . . . Sulphur s6 2 S 2 64 64 Methane CH 4 16 Water H 2 O 18 Hg 200 PROPERTIES OF GASES. 275 < 2 > 5 i a 5 1 M li fe*' l|fl ; a-S-Ti a h 3 is S o o "5 Di*- ?! >-o hJ . lC'*l^CO'-Hb- i ((MCOiOOOi ! ppppppppppppppppoppoop o ;8S8S: O CO CO O >O O CO 'ooooooo I>TtiO"* ll C>cocoeoOO5 >ooo OcOcOcOt^. b-b-OOt ddddd ddddd ddddd do. iiiii iO iO O C ? l^- t-* t^ OO 00 00 OS OS 31 (NCOO5 COCO OOOOO OOOOO ooooo ooooo ooooo o. OS OS OS OS C odddo ooooo COOS IM CO < 00 OC OS OS < O C5 05 Oi < O "*t^ O ''t 1 t -i Tf 00 -i O COOSCCOO >0 >0 CO CO t^ OO^Ort O^l> f t>-t^OOOOOO OSOSO3O< O5OSO5O5O5 O3OSO5OC Jooo 888 OOOOO OOOOO 000- CO CO CO t^ t- t^ 00 00 00 OS OS OS O < OS OS OS OS OS OS OS OS OS OS OS OS O C ddddd ddddd dd^'. CCCOO5C 000< OCOt^O^ t>-r-I^IOO' 8COCOTOOOCCOS NCOCSI SCO TTl Tf Tf 1C "C 'C . ( OOOO OOO< ooooo ooooo OSOSO5O5OS OSOSO5O5C5 OOOOO ddodd ddod-< ^^^^^ OOOOO OOO' -HOO5CI-H -H ' >o o< 11 rH lOCO^GOOS O'-H OOt^OOOs O^HNCO 1 ^ >OCOt^OOOS O ososososos ooooo dddod -< (N(N(NCOCO< t>-t-C > 00 OCX S CM >O OS CN >C 00 frJ 1C 00 1-1 O CO i-i^t^i-i 5 i i I i t CN CN CN CO CO CO **f ^T 1 ^ 1C 1C *C CD C SOSOS CSCSO5OSOS CSOSOSOSOS asOSOSCS -H ^ 00 I-H *& N- 1 4 ^ I s - I-H ^ t^- O ^ t'-OCOt^O CO ^H <-i >-H N WC^fOCOCO Tt< T}< TJ< >C >C iCCDCOCOl>- t^ t^OCO COOCOCOO5 COCDO5C O5 CN C OS CM 1C 00 CM C COCO^' < -^ iCiC>CCOCD O5O5O5O5OS O3 O5 OJ O5 OS ) GO 00 OS OS OSOSOSOSOS OSOSOSOSOS OSOSOSOSOS OSOSOSOSOS OSO5O5OSOS OSO5O5O5OS OS t>l>t^ SO5O5OS >- ( OSOSOSOSOS OSOSOSOSOS OSOSOSOSOS OS OS ( d rHTtiOO i-( TJ< 00 i-i kC OOi i>COO^H *COOcNiCO iCiCiC COCOCOI>b. t^OOOOOOOS OSOSOQO rHrH^HCNCN SOSCSOS OSOSOSOSOS OSOSOSOSOS O3OSOOO OOOOO 1 1C >C i 278 AMERICAN GAS-ENGINEERING PRACTICE. The tension of water-vapor for the temperature observed must be found from tables containing these tensions for the different temperatures, such as the following : TENSION OF AQUEOUS VAPOR IN INCHES OF MERCURY. Tempera- ture, deg. F. Inches of Mercury. Tempera- ture, deg. F. Inches of Mercury. Tempera- ture, deg. F. Inches of Mercury. 40 0.247 57 0.465 74 0.840 41 .257 58 .482 75 .868 42 .267 59 .500 76 .897 43 .277 60 .518 77 .927 44 .288 61 .537 78 .958 45 .299 62 .556 79 .990 46 .311 63 .576 80 1.023 47 .323 64 .596 81 1.057 48 .335 65 .617 82 1.092 49 .348 66 .639 83 1.128 50 .361 67 .661 84 1.165 51 .374 68 .685 85 1.203 52 .388 69 .708 86 1.242 53 .403 70 .733 87 1.282 54 .418 71 .759 88 1.323 55 .433 72 .785 89 1.356 56 .449 73 .812 90 1.401 TENSION OF AQUEOUS VAPOR. Degrees Centigrade. Tension in Millimeters of Mercury. Degrees Centigrade. Tension in Millimeters of Mercury. Degrees Centigrade. Tension in Millimeters of Mercury. -20 0.927 + 2. 5.302 6.4 7.193 -10 2.093 + 2.2 5.378 6.6 7.292 2 3.955 + 2.4 5.454 6.8 7.392 - .8 4.016 + 2.6 5.530 7. 7.492 - .6 4.078 + 2.8 5.608 7.2 7.595 - .4 4.140 + 3. 5.687 7.4 7.699 - .2 4.203 + 3.2 5.767 7.6 7.840 4.267 + 3.4 5.848 7.8 7.910 - o'.8 4.331 + 3.6 5.930 8. 8.017 - 0.6 4.397 3.8 6.014 8.2 8.126 - 0.4 4.463 4. 6.097 8.4 8.236 - 0.2 4.531 4.2 6.183 8.6 8.347 - 0. 4.600 4.4 6.270 8.8 8.461 + 0.2 4.667 4.6 6.350 9. 8.574 + 0.4 4.733 4.8 6.445 9.2 8.690 + 0.6 4.801 5. 6.534 9.4 8.807 + 0.8 4.871 5.2 6.625 9.6 8.925 + 1. 4.940 5.4 6.717 9.8 9.045 + 1.2 5.011 5.6 6.810 10. 9.165 + 1.4 5.0 2 5.8 6.904 10.2 9.288 + 1.6 5.155 6. 6.998 10.4 9.412 + 1.8 5.228 6.2 7.095 10.6 9.537 PROPERTIES OF GASES. 279 TENSION OF AQUEOUS VAPOR Continued. Degrees Centigrade. Tension in Millimeters of Mercury. Degrees Centigrade. Tension in Millimeters of Mercury. Degrees Centigrade. Tension in Millimeters of Mercury. 10.8 9.665 20.6 18.047 32. 35.359 11. 9.792 20.8 18.271 33. 37.410 11.2 9.923 21. 18.495 34. 39.565 11.4 10.054 21.2 18.724 35. 41.827 11.6 10.187 21.4 18.954 40. 54.906 11.8 10.322 21.6 19.187 45. 71.391 12. 10.457 21.8 19.423 50. 91.982 12.2 10.596 22. 19.659 55. 117.478 12.4 10.734 22.2 19.901 60. 148.791 12.6 10.875 22.4 20.143 65. 186 . 945 12.8 10.919 22.6 20.389 70. 233.093 13. 11.162 22.8 20.639 75. 288.517 13.2 11.309 23. 20.888 80. 354.643 13.4 11.456 23.2 21 . 144 85. 433.041 13.6 11.605 23.4 21.400 90. 525.450 13.8 11.757 23.6 21.659 95 633.778 14. 11.908 23.8 21.921 99. 733.21 14.2 12.064 24. 22.184 99.1 738.5 14.4 12.220 24.2 22.453 99.3 741.16 14.6 12.378 24.4 22.723 99.4 743.83 14.8 12.538 24.6 22.996 99.5 746.5 15. 12.699 24.8 23.273 99.6 749.18 15.2 12.864 25. 23.550 99.7 751.87 15.4 13.029 25.2 23.834 99.8 754.57 15.6 13.197 25.4 24.119 99.9 757.28 15.8 13.366 25.6 24.406 100. 760. 16. 13.536 25.8 24.607 100.1 762.73 16.2 13.710 26. 24.988 100.2 765.46 16.4 13.885 26.2 25.288 100.3 768.20 16.6 14.062 26.4 25.88 100.4 771.95 16.8 14.241 26.6 25.891 100.5 773.71 17. 14.421 26.8 26.198 100.6 776.48 17.2 14.605 27. 26.505 100.7 779.26 17.4 14.790 27.2 26.820 100.8 782.04 17.6 14.977 27.4 27.136 100.9 784.83 17.8 15.167 27.6 27.455 101. 787.63 18. 15.357 27.8 . 27.778 105. 960.41 18.2 15.552 28. 28.101 110. 1075.37 18.4 15.747 28.2 28.433 120. 1491.28 18.6 15.945 28.4 28.765 130. 2030.28 18.8 16.145 28.6 29.101 140. 2717.63 19. 16.346 28.8 29.441 150. 3581.23 19.2 16.552 29. 29.782 160. 4651.62 19.4 16.758 29.2 30.131 170. 5961.66 19.6 16.967 29.4 30.479 180 7546.39 19.8 17.179 29.6 30.833 190. 9442.70 20. 17.391 29.8 31.190 200. 11688.96 20.2 17.608 30. 31.548 220. 17390. 20.4 17.826 31. 33.405 224.7 25 atmos. 280 AMERICAN GAS-ENGINEERING PRACTICE. The following tables will be useful in calculating the flow of gases in pipes by Pole's formula given in the chapter upon mains. SQUARE ROOT OF PRESSURE. Water, Inches. Square Root. Water, Inches. Square Root. Water, Inches. Square Root. 0.1 0.3162 1.5 1.2251 2.8 .6733 0.2 0.4472 .6 .2649 2.9 .7029 0.3 . 5477 .7 .3038 3.0 .7320 0.4 . 6324 .8 .3416 3.1 .7606 0.5 0.7071 .9 .3784 3.2 .7888 0,6 0.7745 2.0 .4142 3.3 .8165 0.7 0.8366 2.1 .4491 3.4 .8439 0.8 0.8944 2.2 .4832 3.5 .8708 0.9 0.9487 2.3 .5165 3.6 .8793 1.0 1.0000 2.4 .5491 3.7 .9235 1.1 1.0488 2.5 .5811 3.8 1.9493 1.2 1.0954 2.6 1.6123 3.9 1.9748 1.3 .1401 2.7 1.6431 4.0 2.0000 1.4 1.1832 SQUARE ROOT OF THE SPECIFIC GRAVITY OF GAS. Specific Gravity. Square Root. Specific Gravity. Square Root. Specific Gravity. Square Root. Specific Gravity. Square Root. 0.350 0.5916 0.440 0.6633 0.530 0.7280 0.620 0.7874 .355 .5958 .445 .6671 .535 .7314 .625 .7905 .360 .6000 .450 .6708 .540 .7348 .630 .7937 .365 .6041 .455 .6745 .545 .7382 .635 .7969 .370 .6083 .460 .6782 .550 .7416 .640 .8000 .375 .6124 .465 .6819 .55 .7449 .645 .8031 .380 .6164 .470 .6856 .560 .7483 .650 .8062 .385 .6205 .475 .6892 .565 .7517 .655 .8093 .390 .6245 .480 .6928 .570 .7549 .660 .8124 .395 .6285 .485 .6964 .575 .7583 .665 .8155 .400 .6325 .490 .7000 .580 .7616 .670 .8185 .405 .6364 .495 .7035 .585 .7648 .675 .8216 .410 .6403 .500 .7071 .590 .7681 .680 .8246 .415 .6442 .505 .7106 .595 .7713 .685 .8276 .420 .6481 .510 .7141 .600 .7746 .690 .8306 .425 .6519 .515 .7176 .605 .7778 .695 .8337 .430 .6557 .520 .7212 .610 .7810 .700 .8367 .435 .6595 .525 .7246 .615 .7842 PROPERTIES OF GASES. 281 C. SPECIFIC GRAVITY. Specific Gravity Determination. The relative weight of gases often determines the character of their constituents, whether they contain much or little heavy hydrocarbons or the proportion of hydrogen. Specific gravity is also one of the factors that deter- mine the rate of flow through pipes and occur in Pole's formula. When we say the specific gravity of simple coal-gas is 0.4, we mean o u FIG. 69. Apparatus for Bunsen's FIG. 70. Wooden Mercury Trough for Effusion Test of the Specific Effusion Test. Gravity of Gas. that it is 0.4 as heavy as the same volume of air under like con- ditions. The gas balances of Letheby and Dr. F. Lux weigh the gas directly and thus determine its gravity, but the precautions and corrections are too refined for ordinary works operation. The apparatus devised by Professor Bunsen is applicable, however, and accurate as well. It depends upon the property of gases by which the velocity with which they pass through a small orifice depends upon their specific gravity, or, more exactly stated, the densities of two gases are directly proportional to the squares of the times 282 AMERICAN GAS-ENGINEERING PRACTICE. required for equal volumes under like conditions to pass through the same minute orifice. The apparatus is herewith illustrated and is in two parts, the glass tube for the gas and the stand for the mercury seal, Figs. 69 and 70, as shown by J. A. Butterfield in his 'work on the Chemistry of Gas Manufacture. A thick-walled glass tube has one end hermetically sealed by a platinum-foil diaphragm pierced at its center by a hole about -%fa inch diameter and fitting by a gas-tight ground joint into a long tube B about 0.75 in. in- ternal diameter, provided with a stop-cock C and an internal float D. On the tube a level line K is scribed, and two sets of double lines & in. apart on the float. Mercury is then poured into the top receptacle of the stand, filling the stem and top up to a line on the glass windows in its side. The apparatus is now ready for a test. First dry the tube and float thoroughly; see that the mercury is dry and clean, and fill the tube with gas which has been dried by drawing through calcium chloride; insert the open end of the tube into the mercury-bath and into the stem of the stand until the mark K coincides with the surface of the mercury. The float, which has been inserted into the tube previously, will float upon the mercury, filling the lower portion of the tube, and rise gradually as the pressure expels the gas through the opened stop-cock and the small aperture in the platinum-foil diaphragm. For more accurate observation a telescope is placed at some distance on a level with the mercury, and as the float appears above the surface of the mercury the appearance, of the black scribe lines is watched for, the first one being a warning, and as the second one gets level with the surface of the mercury a stop-watch is started; when the second of the second set of double lines is seen, the watch is stopped and the time elapsed noted. Dried air is then tested in the same manner. If the gas required t minutes and the air t\ minutes and the density of air be taken as 1, we would then have the proportion Sp. gr. gas_ t 2 from which the specific gravity can be found with sufficient accu- racy for ordinary industrial purposes. Several observations should be made of each, however, and the mean used for calculation. Schilling's Apparatus. Another apparatus resembling the Bunsen type is often used in determining the specific gravity of a gas. It is known as the Schilling effusion test, using the apparatus shown in Fig. 71. The outer vessel contains water in which is immersed the inner glass tube, weighted at its lower end to keep it immersed and provided at its upper end with two tubes, PROPERTIES OF GASES. 283 one to the left with a valve and the upright one having a 3-way valve with scale having the positions "vent," "off," and "on" marked upon it. The tube also has two scribe marks encircling it. The vertical tube is terminated by a plati- ^ num-foil disk perforated by a minute hole. The tube is first raised, air enters through the "vent" position of the cock, which is then turned to "off", the tube placed on the bottom and the cock turned to " on," the air thus being forced through the perforation in the platinum foil by the head of water outside. When the water-level inside rises to the lower scribe mark a stop-watch is started, and stopped imme- diately when the water reaches the upper mark. The tube is then charged through the side valve with the gas to be tested, and the time in sec- onds noted as before. Since the velocity of gas passing through such an orifice is propor- tional to the square root of the density, the densities vary as the squares of the times required for the same volume to pass under like conditions, or, if the gas required t g or 120 seconds and the air t a or 180 seconds, Sp.gr. gas = tf Sp.gr.air=l tf (120) 2 = 0.44. FIG. 71. Schilling's Effusion Test. Dr. Letheby devised a more accurate piece of apparatus for the same purpose, consisting of a glass globe having extensions and valves above and below. The upper end, as shown in Fig. 72, is terminated by a tube surmounted by a small gas-burner and containing a sensitive thermometer. The lower end is attached to a gas-jet and gas allowed to flow through until all the air is expelled, when the cock is closed and the upper cock an instant later. The thermometer is then read and the globe weighed complete in a sensitive balance in a dry atmosphere. Previously it had been weighed when filled with air and the weight of air contained corrected to 60 deg. F. and 30 in. barometric pressure; suppose it to have been 31 grains. Suppose the temperature of the gas to have been found to be 56 deg. F., the barometric pressure 30.3 in., and its weight, over the weight when holding a vacuum, found to be 15 grains. The correction for tempera- ture and pressure is 0.98, making the corrected weight of the gas 14.7 at 60 deg. and 30 in. Then 14.7^31=0.47, the specific gravity desired. 284 AMERICAN GAS-ENGINEERING PRACTICE. The volume of this globe can be readily calculated when once the weight of air contained is accurately determined. Since 1 cu. ft. of moist air weighs 532.4 grains and of dry air 535.9 grains, 100 cu. in. of moist air will weigh 30.81 grains, which will contain 0.336 grain of moisture, making the weight of 100 cu. in. to be 30.81 0.336 = 30.474 grains. Suppose the given globe was found to contain 30.964 grains of air at 60 deg. and 30 in.; divide this by 30.474 and the resultant volume of the globe will be 100.5 cu. in. As found in the test the globe con- tained 15 grains of gas; then (15X100) -=-100.5 = 14.92 grains will be the weight of gas it con- tained for 100 cu. in. capacity. Greville Williams described a method for determining the specific gravity of gas in the Transactions of the Gas Institute for 1882. He dries the gas and air before testing, although this is not essential for the method. Balances used in specific gravity determinations must be of extreme accuracy, weighing to one-tenth mil- ligram when the globe need not be over 400 c.c. capacity. The globe is not exhausted and temperature and barometer corrections are avoided by selecting a day when the barometer is steady and keeping the gas and air at the same temperature by means of a gas-stove. The air must first be freed from CO2 and moisture by passing through KOH, then H 2 SC>4, then soda-lime and calcium chloride. The air is drawn through the globe until all trace of other gases is removed, indicated by the globe remaining constant in weight, the cocks are closed, the globe carefully wiped with clean chamois leather and hung by platinum wire to the balance- arm, balanced, and the weight noted; after hanging 5 minutes the weight is noted again. The gas is then passed through the globe for an hour, after first being dried by tubes of calcium chloride) the cocks closed, the one on the supply-pipe end first, and the globe again weighed. Gas may be thus weighed continuously, as long as the barometer and thermometer remain constant. Some tests on hydrogen showed a deviation of 0.0014 from its theoret- ical gravity of 0.0693. Bunsen obtained a value of 0.079, or an error of 0.01, by this method. The specific gravity can now be calculated by this formula: Vnt-P FIG. 72. Letheby Globe for Weigh- ing Gases. D= Vn t PROPERTIES OF GASES. 285 where V= capacity of globe in cubic centimeters; P= difference between the weights of globe with air and with gas, grammes; n= weight of 1 c.c. of air at T deg. C.; D = specific gravity by experiment. The advantage is, of course, the doing away with producing a vacuum in the globe. Dr. Lux invented a balance which goes by his name and is shown in Fig. 73. The globe is at one end of a balance-arm, the FIG. 73. Lux Gas-balance. gas connections dipping into mercury, and the specific gravity is read directly on the scale at the other end, uncorrected for atmos- pheric conditions. Thus air will be 1 on the scale, hydrogen at 0.07, etc. The corrections to be made are for pressure and tem- perature. For every millimeter at which the barometer stands above or below 760 mm. there is added or deducted 0.0007 from the reading on the scale. For every degree C. at which the ther- mometer is above or below 15 deg. C. deduct or add 0.002 to the scale reading. The apparatus requires very careful adjustment, but affords a ready means for determining specific gravity. Specific Gravity of Oils. This can best be found by a specific- gravity bottle, or a carefully graduated hydrometer, the oil being either at 60 deg. F. or 39.1 deg. F. Take a glass-stoppered specific- gravity bottle, weigh it, fill it up to a mark with recently boiled distilled water at 60 deg. or 39.1 deg. F., weigh again, dry with alcohol, fill to the mark on the neck with the spirit or oil to be tested (at 60 deg. or 39.1 deg.), weigh again. Then the weight of oil divided by the weight of the water will equal the specific grav- ity. The coefficient of expansion of petroleum oils is about 0.0036 per deg. F. or 0.0065 per deg. C. To find the weight of a cubic foot of oil, multiply its specific gravity by 62.425, the weight of a cubic foot of water. Oils are usually tested in degrees Baume, 286 AMERICAN GAS-ENGINEERING PRACTICE. the following table therefore being useful in converting Baume degrees into specific gravity. CONVERSION OF HYDROMETER DEGREES INTO SPECIFIC GRAVITY. Degrees Baum6. Specific Gravity, Water = 1.5. Pounds per Gallon. Degrees Baum6. Specific Gravity, Water = 1. Pounds per Gallon. 10 1.0000 8.33 49 0.7821 6.52 11 .9929 8.27 50 .7777 6.48 12 .9859 8.21 51 .7734 6.44 13 .9790 8.16 52 .7692 6.41 14 .9722 8.10 53 .7650 6.37 15 .9655 8.04 54 .7608 6.34 16 .9589 7.99 55 .7567 6.30 17 .9523 7.93 56 .7526 6.27 18 .9459 7.88 57 .7486 6.24 19 .9335 7.83 58 .7446 6.20 20 .9333 7.78 59 .7407 6.17 21 .9271 7.72 60 .7368 6.14 22 .9210 7.67 61 .7329 6.11 23 .9150 7.62 62 .7290 6.07 24 .9090 7.57 63 .7253 6.04 25 .9032 7.53 64 .7216 6.01 26 .8974 7.48 65 .7179 5.98 27 .8917 7.43 66 .7142 5.95 28 .8860 7.38 67 .7106 5.92 29 .8805 7.34 68 .7070 5.89 30 .8750 7.29 69 .7035 5.86 31 .8695 7.24 70 .7000 5.83 32 .8641 7.20 71 .6990 5.80 33 .8588 7.15 72 .6956 5.78 34 .8536 7.11 73 .6923 5.75 35 .8484 7.07 74 .6889 5.72 36 .8433 7.03 75 .6829 5.69 37 .8383 6.98 76 .6823 5.66 38 .8333 6.94 77 .6789 5.63 39 .8284 6.90 78 .6756 5.60 40 .8235 6.86 79 .6722 5.58 41 .8187 6.82 80 .6666 5.55 42 .8139 6.78 81 .6656 5.52 43 .8092 6.74 82 .6619 5.50 44 .8045 6.70 83 .6583 5.48 45 .8000 6.66 84 .6547 5.45 46 .7954 6.63 85 .6511 5.42 47 .7909 6.59 90 .6363 5.30 48 .7865 6.55 95 .6222 5.18 PROPERTIES OF GASES. 287 D. SPECIFIC HEAT. Specific Heat Defined. This term denotes the amount of heat, expressed in heat-units, which is required to raise by 1 the tem- perature of unit weight of a substance. Since a heat-unit is the amount of heat required to raise by 1 the temperature of unit weight of water, the specific heat of a substance is the ratio between the amount of heat needed to raise by 1 the temperature of unit weight of the substance and the amount of heat required to raise by 1 the temperature of unit weight of water. If the unit of weight is the pound avoirdupois, and the temperature is measured in Fahrenheit degrees, the specific heat is expressed in British ther- mal units, while if the unit of weight is the kilogram, and the temperature is measured in centigrade degrees, the specific heat is expressed in calories. It is expressed by the same number in each case. More heat is required to raise the temperature of unit weight of water a given amount than is needed to raise by the same amount the temperature of unit weight of any other sub- stance, with the exception of hydrogen; therefore, with this excep- tion, the specific heats of all substances are less than 1. The amount of heat required to raise by 1 the temperature of a body which is free to expand, or, as it is said, is kept under constant pressure, is not the same as the amount required to pro- duce the same change in temperature in the body if it is kept at a constant volume. For every substance there are, therefore, two values for the specific heat, one for constant pressure and one for constant volume. There is also what is termed specific heat by volume, which is the amount of heat, expressed in heat-units, required to raise by 1 the temperature of unit volume of a sub- stance. But when the term "specific heat" is used without any qualification, as in the statement "the specific heat of nitrogen is 0.244," it refers to specific heat by weight and at constant pres- sure. The relative illuminating value of the different hydrocarbons contained in water-gas has been stated as follows when the gas is tested in a burner consuming it at 5 cu. ft. per hour: Benzene C 6 H 6 349.0 Ethane C 2 H 6 35.0 Ethylene C 2 H 4 68.5 Methane CH 4 5.0 288 AMERICAN GAS-ENGINEERING PRACTICE CALCULATING MEAN SPECIFIC HEAT IN A GAS. Constituent. Per Cent by Volume. Weight of 1 Cu. Ft. in Pounds. Weight of Constituent in Pounds. Specific Heats. Sp. H. X Wt.XVol. Authority for Value of Sp. H. Benzol. . . . C 2 H 4 CO 1.00 3.75 8.04 0.20640 0.07410 0.7407 0.20640 0.27787 . 59552 .187 .245 .403 0.2450 0.3460 0.8355 Wullner. t ( n H 47.04 0.00530 0.24931 .396 . 3580 Regnault CH 4 36.02 0.04234 1 . 52508 .319 2.0115 Masson. CO, O N 1.60 0.39 2.15 0.11637 0.08463 07429 0.18619 0.03300 16046 .300 .405 1 405 0.2420 0.0464 . 2255 t ( Regnault. 100 00 3 22383 4 3099 4.3099 3.2283 = 1.337, the value of the mean specific heat for the above gas. TABLE OF MEAN SPECIFIC HEATS AT CONSTANT PRESSURE. (In B.t.u. per Pound.) Degrees Fahrenheit. Carbon Dioxide. Water- vapor. Nitrogen. Oxygen. 212 0.201 0.446 0.244 0.214 392 0.210 0.462 0.249 0.218 572 0.219 0.478 0.253 0.222 752 0.227 0.494 0.257 0.225 932 0.236 0.510 0.262 0.229 1112 0.245 0.526 0.266 0.233 1292 0.254 0.541 0.270 0.237 1472 0.263 0.557 0.275 0.241 1652 0.271 0.573 0.279 0.244 1832 0.280 0.589 0.284 0.248 2012 0.289 0.605 0.288 0.252 2192 0.298 0.621 0.292 0.256 2372 0.307 0.637 0.297 0.260 2552 0.315 0.652 0.301 0.264 2732 0.324 0.668 0.305 0.267 2912 0.333 0.684 0.310 0.271 3092 0.342 0.700 0.314 0.275 3272 0.351 0.716 0.318 0.279 3452 0.360 0.732 0.323 0.282 3632 0.368 0.748 0.327 0.286 3812 0.377 0.764 0.331 0.290 3992 0.385 . 0.780 0.336 0.294 4172 0.394 0.796 0.340 0.298 4352 0.403 0.812 0.344 0.301 4532 0.412 0.828 0.349 0.305 Inaccuracies in the experimental data on which this table is based render it useless to attempt to interpolate more closely than to ninety degrees. PROPERTIES OF GASES. 289 SPECIFIC HEATS AT CONSTANT PRESSURE. Air 0.2375 Oxygen 0.2175 Hydrogen 3 . 4090 Nitrogen . 2438 Carbon dioxide, CO 2 0.2170 Carbon monoxide, CO . 2479 Olefiant gas (ethylene), C 2 H 4 0.4040 Marsh gas (methane), CH, 0.5929 Blast-furnace gas . 2280 Chimney gases from boilers . 2400 Steam, superheated 0.4805 "VOLUMETRIC" SPECIFIC HEATS. Air, oxygen, carbon monoxide, hydrogen, and nitrogen = 0.019. Carbon dioxide and marsh gas = 0.027. Producer gas = 0.019. Volumetric specific heat is the quantity of heat required to raise the temperature of 1 cubic foot 1 degree from 32 to 33 F. SPECIFIC HEAT OF SOLIDS AND LIQUIDS. (Water = 1.) Substance. Specific Heat. Substance. Specific Heat. Acetic acid 6589 Lead 0314 Alcohol (sp gr 793) 622 Lime burned . 217 Aluminium 2143 Lithium 9408 Antim ny cast 05077 Magnesium 2499 Arsenic 0814 Manganese 0.1217 Beeswax 0.45 Marble, white 21585 Benzine . 3952 Mercury . 03332 Birch 48 Nickel 10863 Bismuth 03084 Oil olive 3096 Brass . 09391 Oil sweet 31 Brick, common Brick fire 0.2 22 Oil of turpentine Palladium 0.472 05928 Cadmium 05669 Phosphorus . . 18949 Chalk, white 0.21485 Pine 65 Charcoal, animal, calcined. . 26085 Platinum 03243 Charcoal, wood 0.24111 Potassium . 1606 Clay white burned 185 Selenium 07616 Ccal. 2777 Silicon crystallized 1774 Cobalt 10696 Silicon f u sed 175 Copper 09215 Silver 05701 Diamond c. 14687 Sodium 2934 Ether 5207 Spermaceti 32 Glass 19768 Steel 1175 Gold 03244 Sulphur 20259 Graphite 20187 Sulphuric acid . ... 222 Ice 504 Tellurium 4737 Iodine 05412 Thallium 0336 Iron, cast 12983 Tin 05695 Iron, wrought 11379 Zinc 09555 290 AMERICAN GAS-ENGINEERING PRACTICE. SPECIFIC HEAT OF GASES AND VAPORS. Specific Heat of Equal Weights. Specific Heat of Equal Volumes. Specific Heat of Constant Volumes. Simple Gases Air. . 0.2374 0.2175 0.2438 3.4090 0.1210 0.0555 0.2374 0.2405 0.2370 0.2359 0.2962 0.3040 . 1687 0.1559 0.1740 2.4096 Oxygen. . Nitrogen Hydrogen Chlorine Biomine Compound gases Binoxide of nitrogen 0.2315 0.2450 0.2163 0.2432 0.1553 0.1845 0.2262 0.2317 0.5083 0.5929 0.4040 0.2406 0.2370 0.3307 0.2857 0.3414 0.2333 0.3447 0.2406 0.2966 0.3277 0.4106 0.1768 0.1714 0.1246 0.4683 Carbonic oxide Carbonic acid Sulphureted hydrogen Sulphurous an ydride Hydrochloric acid Nitrous oxide Nitric oxide Ammonia Marsh gas Olefiant gas (ethylene) Vapors Water (steam) 0.4805 0.4810 0.1567 0.4534 0.5061 0.1570 0.3754 0.4125 0.2984 1.2296 0.6461 0.7171 2.3776 0.4140 1.0114 0.8244 0.3337 0.3411 0.3200 Ether Chloroform Alcohol Turpentine Bisulphide of carbon Benzole . . . The following figures are given by D. K. Clark in his treatise: Substance. Specific Heat. Substance. Specific Heat. Ice 0.504 Brickwork, masonry. . . . 0.200 Water at 32 F 1 000 Coal 2411 Gaseous steam 475 Anthracite 2017 Saturated steam 305 Oak wood 570 Mercury 0.0333 Fir wood . 650 Sulphuric ether Alcohol (0.715)0.5200 . 6588 Oxygen (constant wt. and vol.) 0.1559 Lead 0.0314 Air (const, pres.) 0.2377 Gold 0.0324 Air (con naturally higher, the value of C is multiplied by === . There is another correction not yet mentioned, the heat carried off by the moisture condensed from the water vapor formed during com- PROPERTIES OF GASES. 297 bustion, which escapes from tube No. 35 shown in the section. When 1 kilogram of hydrogen burns to form 9 kg. of water vapor, at 100 deg. C. (212 deg. Fah.) it generates 28732 calories, but if this vapor is brought to deg. C. the heat given up is 34462, the difference being due to the latent heat of the steam and in the water formed. As calorimeter results may vary as much as 10 per cent from this cause, it is always well to state whether the calories found are gross or net. The correction is easy, consisting in deducting from the calories found by the formula 0.636 calories per cubic centimeter of water of condensation collected ; as less than 1 c.c. of water is thus collected per liter of gas, it is generally meas- ured after the series of tests. Example. In a 5.5-minute test by Bates in which three read- ings were made on the gases and twelve on the water, the averages were found to be: 7^=25.6 deg., 7^=20 deg., T IW = 14.739 deg., T w= 29.76 deg., (7=4.5 liters, W =1.74 liters. Substituting these values in the formula we get 1.740(29.76-14.739) 1000+0.01 (14.739-25.6) +2.466(20-14.739) 4.5 =5820.985 calories per cubic meter. Applying now the temperature correction we find that at deg. C. the calorific value will be (273 + 2^ fi\ 273 / 6344 - 8736 calories - To reduce this to B.t.u. per cu. ft. multiply by 0.11236, thus: 6344.8736X0.11236=712.9099 B.t.u. Liquid Fuels. This instrument can also be used to test liquid fuels, such as oils, alcohol, turpentine, naphtha, kerosene, gasoline distillate or petroleum, the arrangement of apparatus being shown in Fig. 79. Instead of the gas-meter, governor, and burner are substituted scales upon one arm of which is suspended a burner suitable for burning the liquid fuel. At the beginning of the test the lamp is lighted and inserted, the scales are balanced with the lamp end slightly low, the water supply is adjusted as with gas, and as the beam comes to a perfect balance, the water-outlet is switched into the empty graduate and readings taken as with gas. Place a weight on the weight-pan equal to the quan- 298 AMERICAN GAS-ENGINEERING PRACTICE. FIG. 79. Junker's Calorimeter Adapted for Liquid Fuels. PROPERTIES OF GASES. 299 tity it is desired to test, and as the beam again comes to equilibrium take final readings quickly. The calorific value is then calculated by this formula: W(T ow -T IW )lWOm where Gr C= calories per kilogram; GQ = weight of fuel burned in milligrams; the other terms being the same as before. Calories per kilogram can be reduced to B.t.u. per pound by multiplying the calories by 1.8. THE SIMMANCE-ABADY GAS-CALORIMETER. With the purpose in mind of devising a calorimeter by which quick tests could be made with the greatest chance of accuracy, FIG. 80. Arrangement of Simmance- FIG. 81. Sections of Simmance- Abady Gas-calorimeter with Ther- Abady Calorimeter, mometers Used. Messrs. Simmance and Abady, two consulting chemists of London, invented the calorimeter which bears their names. It is of the 300 AMERICAN GAS-ENGINEERING PRACTICE. Junker type with distinct improvements. Short and rapid tests may be made with it, taking but a few seconds by reason of the convenient arrangement of instruments to be read, and but a minute to make a complete test for calorific power of a gas. The rapidity at which gases can be burned can be regulated, the relative area exposed to the burning gases is increased, the thermometers are arranged together and with magnified scales for quick reading, the head of water entering can be determined with positive accu- racy, and every effort made to secure an instrument which combines quickness with accuracy. In the accompanying illustrations the water-inlet is shown at A, cock at B, whence the water rises in the tube C to a height equal to its pressure, flows around the thermometer D in centigrade degrees divided into tenths, thence through annular shells E, down tubes F, up through tubes G, past the baffle-plate into the upper space H containing a thermometer J, and escapes at K either through the waste-pipe L, or into the graduated measure M of 1000 c.c. capacity in 2 c.c. graduations. The consumed gas rises through N to 0, where the temperature is low enough for the water-vapor formed to condense, falls down through the passages P to the chamber below, which is about the temperature of the air entering the burner chamber, and escapes through a shutter with thermometer at Q, the condensed moisture being collected at R. For every cubic centimeter of this condensed vapor of water thus collected per cubic foot of gas burned 0.6 calorie must be deducted from the gross . calories per cubic foot, or 2.382 B.t.u. per cubic centimeter per cubic foot of gas burned must be deducted from the gross B.t.u. per cubic foot. In setting up the calorimeter the instructions of the makers should be fol- lowed closely, being very careful in handling all its parts. The gas supply must be under uniform pressure. The operation is similar to that of the Junker. The water supply must be under uniform pressure, preferably from an elevated tank provided with a ball valve, as indicated by the height of the float or water in the tube C. Light the gas-burner outside ancj put it in place, adjusting the flow of gas to get the best com- bustion results, adjust the damper at G so that the products of combustion are of the same temperature as the entering water, take the temperature of the gas and air of the laboratory, and the barometric reading. As the meter-hand passes zero mark turn the outlet running water into the graduate M, and as the hand passes a determined point, say 12, switch the water back into the waste-drain ; repeat the test twice, and take the mean of the three readings. Suppose 362 c.c. water were collected in M; gas burned 12 divisions, or 0.06 cu. ft.; difference in temperature of inlet and PROPERTIES OF GASES. 301 J5nd E fetation &*<** le*alin FiQ. 82. The Earnshaw Blue-glass Pyrometer. 302 AMERICAN GAS-ENGINEERING PRACTICE. exit water, 21.7 12.5=9.2 deg. C. The makers supply a table in which 12 will be found at the head of a column, 362 in left- hand column, and 18.1 opposite, which being multiplied by 9.2 equals 166.52 calories per cu. ft.; or, 166.52X3.97 = 661.08 B.t.u. per cu. ft. of gas. The method thus simplified is not laborious. Suppose 3 c.c. of condensation water was collected, or 36 c.c. per cu. ft.; then 36X0.6 = 21.6 calories, which taken from 166.52 calories leaves 144.92 calories per cu. ft., net. Or, 36X2.382 = 85.75 B.t.u., which subtracted from 661.08 B.t.u. is 575.32 B.t.u., net. The same modifications can be made for testing oils as described under the Junker instrument. Another improved form has been devised by the Metropolitan Gas Referees of London, which aims still further to absorb the heat of combustion by the circulating water. F. TEMPERATURES. The Earnshaw Blue=glass Pyrometer, herewith illustrated in Fig. 82, is of the visual type, its principle being the absorption of light of its diminution, through the use of a varying number of slides or blue-glass lenses to create a vanishing point of light, said light of course presumed to vary directly as the intensity of the heat observed. As the personal equation is very marked in the use of an instrument of this kind, its use would of course be of little service in establishing absolute values, but it will be found of extraordinary usefulness in making comparisons or establishing empiric tests. Gas. The theoretical flame temperature of a gas is the highest temperature that can be obtained by the combustion of the gas when no heat is lost in any way, all the heat that is developed being employed to heat up the products of com- bustion. Hydrogen and hydrocarbon gases containing a large percentage of hydrogen yield upon combustion large weights of aqueous vapor, which has a high specific heat, and consequently, in spite of their high heating value, do not produce as high flame temperatures as do such gases as carbonic oxide, which have a lower heating value, but give smaller weights of products having a lower specific heat than aqueous vapor. Since when the gas is burned in air the weight of the nitrogen mixed with the oxygen in the air is added to that of 'the products of combustion, the flame temperature is lower when the combustion takes place in air than it is for combustion in oxygen, as is practi- cally illustrated in the oxyhydrogen flame. PROPERTIES OF GASES. 303 The highest temperature that can theoretically be obtained by burning a gas in air is the temperature that will be reached when no heat is lost in any way ; all the heat developed being employed to heat up the products of combustion and the nitrogen accom- panying the oxygen drawn from the air for this combustion. These conditions are of course never obtained hi practice, but, as it is very hard to measure accurately the losses that occur in practice, the maximum theoretical temperatures are used to furnish a basis for comparisons between different gases, it being assumed that the 'relations between the temperatures actually obtained will be nearly the same as those existing between the theoretical tempera- tures, although the absolute temperatures will be very different hi the two cases. This maximum theoretical temperature evidently depends upon the quantity of heat developed by the combustion of a unit weight of gas and upon the quantity of heat required to raise, by one degree, the temperature, of the products resulting from the com- bustion of this unit weight, and the quotient obtained by dividing the quantity of heat produced by the quantity required to raise the temperature of the products of combustion one degree will give the highest temperature that can be reached by burning the given gas. The quantity of heat produced is given by the calorific value of the gas. The amount of heat required to raise the temperature of the products of combustion one degree can be calculated by multiplying the weight of each product that is produced by its specific heat, the nitrogen mixed with the oxygen in the air and drawn into the flame with it being included. It is therefore neces- sary to determine what substances are produced by the combustion of the gas and the weight of each of these substances that is ob- tained from the unit weight of the gases, to multiply the deter- mined weight of each substance by its specific heat, and to add together the numbers obtained by these multiplications, the sum forming the divisor of the fraction. The maximum temperature that can be produced by burning a gas in air can therefore be determined by dividing the calorific value of the gas per pound by the sum of the numbers obtained, by multiplying the weight of each of the products of combustion produced from one pound of gas by its proper specific heat, the nitrogen mixed in the air with the oxygen required for combustion being considered as one of the products of the combustion. To illustrate by a simple example, the maximum temperature that can be produced by the combustion of carbonic oxide, CO, may be determined as follows: 1 Ib. of CO requires for its combustion to carbonic acid, CO2, 0.571 Ib. of oxygen, which will have mixed with it in the air 304 AMERICAN GAS-ENGINEERING PRACTICE. 0.571X3.31 = 1.89 Ibs. of nitrogen, N, and the products of the combustion of 1 Ib. of CO will therefore be 1.571 Ibs. of CO 2 and 1.89 Ibs. of N. The calorific value of CO is 4383 B.t.u. per pound, the specific heats of CO 2 and N are respectively 0.217 and 0.244, and the equation of the maximum temperature in degrees Fahren- heit is 4383 _4383 1.571X0.217 + 1.89X0.244 0.802 5465 F. Melting=points. For the determination of moderately high temperatures, such as that of hot blast supplied to furnaces, use is often made of metals or alloys of known melting-points, and wher- two such substances are procurable with melting-points differing only by a few degrees, the temperature of the blast, etc., can be readily kept within that range by regulating the heating apparatus, so that one test-piece is liquid and the other solid. By employing a series of test-pieces whose melting-points ascend by small and fairly regular increments a tolerably reliable measurement can be made of any temperature within the range of the test-pieces. Princeps alloys furnish us with fairly good means of reading temperatures between the melting-point of silver and that of platinum. MELTING-POINTS OF PRINCEPS ALLOYS. Percentage Composition of Alloy. Melting- Percentage Composition of Alloy. Melting- point, deg. C. point, deg. C. Silver. Gold. Platinum. Silver. Gold. Platinum. 100 954 60 40 1320 80 20 975 55 45 1350 60 40 995 50 50 1385 40 60 1020 45 55 1420 20 80 1045 40 60 1460 100 1075 35 65 1495 95 'S 1100 30 70 1535 90 10 1130 25 75 1570 85 15 1160 20 80 1610 80 20 1190 15 85 1650 75 25 1220 10 90 1690 70 30 1255 5 95 1730 65 35 1285 100 1775 The values of the higher melting-points are probably within some twenty degrees of the truth. PROPERTIES OF GASES. 305 TEMPERATURES OF MOLTEN IRON CORRESPONDING TO CERTAIN COLORS (POUILLET). Deg. Fah. Intense white 2730 Bright white 2550 White heat 2370 Bright orange 2190 Orange 2010 Bright cherry 1830 Cherry-red 1650 Brilliant red 1470 Dull red 1290 Faint red . 977 MELTING-POINT OF CAST IRON. Deg. Fah. White 1920 to 2010 Gray 2010 to 2090 Optical Pyrometer. The St. Jacques Lunette Pyrometrique is a polariscope arranged for plane polarized light, having between the analyzing and polarizing prisms a quartz crystal about 11 mm. long which has been cut perpendicular to its principal axis. The plane of polarization will be turned by such a piece of quartz through an angle that varies directly as the thickness of the quartz, and (approximately) inversely as the wave length of the light, so that the amount of rotation is much larger for the violet end of the spectrum than for the red. The higher the temperature the INDICATIONS OF THE LUNETTE PYROMETRIQUE. Character of Light. Rotation Angle (Degrees). Approximate Corresponding Temperature. C. Fah. Incipient cherry-red 33 40 46 52 57 62 66 69 84 800 900 1000 1100 1200 1300 1400 1500 1470 1650 1830 2010 2190 2370 2550 2730 Cherry-red. . Light cherry-red Slightly orange Bright orange ... .... White . . Welding white Brilliant white Bright sunlight. . 306 AMERICAN GAS-ENGINEERING PRACTICE. larger, the proportion of light rays of short wave-lengths, conse- quently the larger the angle through which the analyzer must be rotated in order to obtain the " Extinction Tint"; this for low temperatures is a grayish yellow charged by a slight turning of the analyzer in either direction to green or red ; for higher temperatures it is the same as for sunlight, a neutral purple changing to blue or red. For low temperatures where the light is feeble a condensing lens is employed to concentrate the beam for the polarizer. No useful indication can be obtained below incipient cherry-red. (See table at bottom of page 305.) TEMPERATURES. Degrees Fahrenheit = Degrees Centigrade +32, or F.=1.8 C.+32. Degrees Centigrade = | (Degrees Fahrenheit -32). Degrees Absolute Temperature, T. = C.+273. " " " T. = F. + 491. Absolute Zero= 273 on Centigrade Scale. " =- 491 on Fahrenheit Scale. Mercury remains liquid to 39 C., and thermometers with com- pressed N. above the column of mercury may be used for as high temperatures as 400 to 500 C. . HEAT-UNITS. A French Calorie =1 Kilogram of H 2 O heated 1 C. at or near 4C. A British Thermal Unit (B.t.u.) = l lb. of H 2 O heated 1 F. at or near 39 F. A Pound-Calorie Unit = 1 lb. of H 2 O heated 1 C. at or near 4 C. 1 French Calorie = 3.968 B.t.u. = 2.2046 Pound-Calories. 1 British Thermal Unit = .252 French Calories =.555 Pound- Calories. 1 Pound-Calorie =1.8 B.t.u. = .45 French Calories. 1 B.t.u. = 778 ft .-lbs. = Joule's mechanical equivalent of heat. 1 H.P. =33,000 ft.-lbs. per minute = 8^004 = 42.42 B.t.u. per minute = 42.42X60 = 2545 B.t.u. per hour. The British Board of Trade unit is not a unit of heat, but of electrical measurement and = 1 kilowatt hour = 1000 watts = SW= 1.34 H.P. per hour. PROPERTIES OF GASES. 307 TEMPERATURES IN SOME INDUSTRIAL OPERATIONS. Centigrade Fahrenheit Degrees. Degrees. Gold Standard alloy, pouring into molds 1180 2156 Annealing blanks for coinage, furnace cham- ber 890 1634 Silver Standard alloy, pouring into molds 980 1796 Steel Bessemer Process, Six-ton Converter: Bath of Slag 1580 2876 Metal in ladle 1640 2984 " " ingot mold 1580 2876 Ingot in reheating furnace 1200 2192 " under hammer 1080 1976 Siemens Open-hearth Furnace: Producer-gas near gas-generator 720 1328 ' ' entering recuperator chamber . . . 400 752 leaving " " ... 1200 2192 Air issuing from ... 1000 1832 Products of combustion approaching chimney. 300 590 End of melting pig charge 1420 2588 Completion of conversion 1500 2732 Pouring steel into Iad.e { Jg^; ; ; ; ; ; ; ; *j gJJ In the molds 1520 2768 Siemens Crucible Furnace: Temperature of hearth between crucibles 1600 2912 Blast-furnace on Gray Bessemer: Opening in front of tuyere 1930 3506 , , , . , i j beginning to tap 1400 2552 Moltenmetal 1 end of tap . 1570 2858 Siemens Glass-melting Furnace: Temperature of furnace 1400 2552 Melted glass 1310 2390 Annealing bottles 585 1085 Furnace for hard porcelain, end of "baking".. 1370 2498 Hoffman red-brick kiln, burning temperature.. 1100 2012 MELTING-POINTS. P. Sulphur 115 239 Copper 1054 1929 Tin 230 446 | Cast iron, white. . . 1135 2075 Lead 326 618 " " gray... 1220 2228 Zinc 415 779 Steel, hard 1410 2570 Aluminium 625 1157 " mild 1475 2687 Silver 945 1733 | Palladium 1500 2732 Gold 1045 1913 i Platinum 1775 3227 308 AMERICAN GAS-ENGINEERING PRACTICE. MELTING-POINTS (ANOTHER AUTHORITY). Substance. Degrees Fah. Substance. Degrees Fah. Aluminium 1247 Phosphorus Ill Antimony 797 Platinum 3227 Bismuth . . . 505 Potassium 136 Bronze 1652 Silver 1832 Butter 91 Sodium 203 to 204 Copper 2102 Spermaceti. 120 Gold 2192 Stearine. . . 131 " coined 2156 Steel 2372 to 2552 Ice 32 Sulphur , 230 Iodine 237 Tin 540 Iron cast 1922 to 2382 Wax, white 154 ' ' wrought . 2732 to 2912 Wax, yellow 144 Lead 617 Zinc 786 G. HEAT DATA. Heat Radiation. Good heat radiators are good absorbers to an equal degree, and reflecting power is the exact inverse of radiat- ing power. EELATIVE VALUE OF RADIATORS. Substance. Relative^Radiating Lampblack or soot 100 Cast iron, polished 26 Wrought iron, polished 23 Steel, polished 18 Brass, polished 7 Copper, polished 5 Silver, polished 3 Conduction is the transfer of heat by contact, molecular motion being then directly caused. Heat is thus transmitted through the thickness of a furnace-tube. There are good and bad con- ductors, the former being chosen for fire-boxes, other properties being suitable. RELATIVE VALUE OF GOOD HEAT CONDUCTORS. Substance. Relative^Conducting Silver 100* Copper 73.6 Brass 23.1 Iron 1.91 Steel 11.6 Platinum 8.4 Bismuth 1.8 Water.. 0.147 PROPERTIES OF GASES. 309 Bad conductors are of value for covering boilers, steam-cylin- ders, pipes, etc. RELATIVE VALUE OF HEAT INSULATORS. Substance. Relative^Insulating Silicate cotton or slag wool 100 Hair felt 85.4 Cotton wool 82 Sheep's wool 73.5 Infusorial earth 73 . 5 Charcoal 71 . 4 Sawdust 61 .3 Gas-works breeze 43 . 4 Wood, and air-space 35 .7 EXPANSION OF LIQUIDS IN VOLUME. Volume at 32 deg. Fah. = l. Volume at 212 deg. Fah. Water 1.046 Oil 1.080 Mercury 1 .018 Spirits of wine 1 . 110 Air 1.373 to 1.375 LINEAL EXPANSION OF METALS PRODUCED BY RAISING THEIR TEMPERATURE FROM 32 TO 212 FAH. Zinc 1 part in 322 Lead " " " 351 Tin (pure) " " " 403 Tin (impure) " " " 500 Silver " " " 524 Copper " ll "581 Brass.. . " " " 584 Gold 1 part in 682 Bismuth " " " 719 Iron " " " 812 Antimony " " " 923 Palladium " " " 1000 Platinum " " " 1100 Flint glass " " " 1248 COEFFICIENTS OF LINEAR EXPANSION. Elongation per deg. C. Glass 0.0000085 Platinum 0000085 Cast iron 00001 Wrought iron 000012 Copper 000017 Lead 000028 Zinc 00003 Brass. . .000019 310 AMERICAN GAS-ENGINEERING PRACTICE. RELATIVE POWER OF METALS FOR CONDUCTING HEAT. Iron 374.3 Zinc 363 Tin 303.9 Lead. . .179.6 Gold 1000 Silver 973 Copper 898.2 Platinum. . 381 Quantity of Heat Lost by a Square Unit of Exterior Pipe Surface Excess of Temperature in the Gas in the Pipes over that of the Atmosphere. For an Excess of When Radiating in Air. When Plunged in Water. 10. . 8 18 29 40 53 88 266 5,353 8,944 13,437 20. . 30 40 50 COMPARATIVE POWER OF SUBSTANCES FOR REFLECTING RADIANT HEAT. Polished brass 100 Silver 90 Tin 80 Steel 60 Lead 60 Glass 10 Lampblack RELATIVE POWER OF METALS FOR REFLECTING HEAT. Intensity of direct radiation =1.00. Silver plate 0.97 Gold 0.95 Brass 0.93 Speculum metal . 86 Tin.. . 0.85 Polished platinum 0.80 Steel 0.83 Zinc 0.81 Iron. . .0.77 CHAPTER XX. STEAM. A. PROPERTIES OF STEAM. THE conversion of water into steam is attended with certain heat phenomena which may be developed as follows: Latent Heat. The term latent heat is applied to the heat added to or abstracted from a substance to change its state with- out changing its temperature. Thus 144 B.t.u. must be added to 1 pound of ice to convert it into water at 32 deg. F. This can be found by direct experiment by allowing ice to melt in water, the heat lost by the water being absorbed by the ice. Suppose 2 oz. (wi) of ice at 32 deg. F. are added to 20 oz. of water (w) at 60 "deg. F. (ti) which was at 45 deg. F. when the ice was melted, 1 deg. being obtained from the higher temperature of the room, making the corrected final temperature (t 2 ) 44 deg. F. Then Heat lost by the water = heat gained by the ice. wfo-ti) =w ] [L+(t 2 -32)] } 20 (60 - 44) = 2[L + (44 - 32)], Latent heat, L= (320-24)^2=148. The exact value is more nearly 144 B.t.u. The calorimeter shown in Fig. 83 is often used for such experiments. A metal vessel B contains in its air-space another vessel surrounded by non-conducting ma- terial like felt and is provided with a ther- mometer for taking the temperature of the water. The Siemens pyrometer resem- bles this apparatus, the copper cylinder being brought up to the temperature of the furnace to be tested and then quickly thrown into the known weight of water; when the temperature becomes constant after gently stirring the heat lost by the copper will equal the heat gained by the water, as before, but the calculation is as -^ FIG. 83. Calorimeter, follows : 311 312 AMERICAN GAS-ENGINEERING PRACTICE. Weight > specific heat X decreased temperature of copper = weight X increased temperature of the water. where T is the temperature of the furnace and the other terms have the same values as before. When water is heated the rise in temperature ceases at 212 deg. F. (100 deg. C.) until all the water has been converted into steam without raising the pressure. The heat continually added goes to change the condition of water from that of a liquid to a vapor. This heat may be determined by the apparatus shown in Fig. 84. FIG. 84. Apparatus for Testing Latent Heat of Steam. Water is boiled in flask A, steam passing from A through B to flask C into water, which condenses it. This continues until the water in C nearly boils. The difference in weight of C before and after the test will give the weight of steam condensed (w). Since the heat lost by the steam equals that gamed by the water, or if there was 20 oz. of water in C at 70 deg. F. and the steam condensed was 1.5 oz., increasing the temperature to 147 deg., 1.5(212 + 1*- 147) = 20(147-70), L h = (1540-97 5)+- 15 = 931.6 B.t.u. The exact value for the latent heat of steam is 966 B.t.u. It should be well grasped that latent heat is a kind of specific heat given to the body during the change from solid to liquid and from liquid to gaseous. In the reverse order an equal quantity of heat is given out. Thus 1 Ib. of ice below 32 will give out or absorb 0.5 unit for every degree, and 144 units when melting. Water between 32 and 212 will require 1 unit per Ib. Finally, if the steam be superheated beyond 212, 0.48 unit will raise each pound by one degree at a time. STEAM. 313 Fig. 85 shows the changes indicated, ABC being the curve of volumes, with DEF as base, and the dotted line a curve of corre- NCREASINQ WITH TEMP. BYxGAY LUSSAC'S FORMULA spending temperatures. The base-line lengths indicate units of heat required to change both volume and temperature under atmos- 314 AMERICAN GAS-ENGINEERING PRACTICE. pheric pressure. The steam volume at F is too great to be shown on the diagram, but is given to a smaller scale at G and to a still smaller scale at C. The base of these narrow triangles corresponds to EF. Water will boil at 212 F. under 14.7 Ibs. per sq. in. pressure, but if the pressure is decreased the boiling-point is lowered, and if the pressure increases the boiling-point will be above 212 deg. When steam is in contact with boiling water it is wet or saturated, but when all water has been evaporated it becomes dry steam; further addition of heat forms superheated steam, which behaves like a fixed gas in that condition. In Fig. 85 the volume of steam is 1650 times that of the water from which it was formed, while 1 Ib. of water will form 26.36 cu. ft. of steam. The relation of temperature to pressure for the range of 32 to 32 deg. F. was tested by Gay-Lussac hi the apparatus shown in FIG. 86. FIG. 87. FIG. 86. Tension of Aqueous Vapor at Low Temperatures. FIG. 87. Tension of Aqueous Vapor at Medium Range. Fig. 86, consisting of two barometer tubes hi mercury, tube B containing some water above the mercury in its end, the tempera- ture of which was regulated by freezing-mixtures as shown. For the temperature ranges from 32 deg. to 122 deg. Itegnault used the apparatus shown in Fig. 87, hi which tube B again has a little water on the surface of the mercury. The ends of the barom- eter tubes are surrounded by water which is readily brought to the temperature desired. The tension of aqueous vapor and steam between the tempera* tures of 122 deg. and 219 deg. F. (since it has been carried to 432 STEAM. 315 deg.) was found by Regnault in the apparatus shown in Fig. 88, where A is a boiler in which steam is formed which is condensed by the water-jacket circulating water from D to E, B is a copper sphere in which the pressure is regulated by the pump C and measured by the U gage F. The thermometers in A measure the temperature of the steam, and the very high tube G permitted of pressures up to 24 atmospheres. The relation between temperature and specific volume or cubic feet per pound was determined by Fairbairn and Tate in the appa- ratus shown in Fig. 89, where a glass sphere A dips its open stem into mercury in tube E connected with B, containirg water. A known weight of water is placed in A while D and B are heated. As the tension in A and B are eqr.al at first the mercury columns are at the same level, but when the water in A has evaporated, FIG. 88. Vapor Tension of Steam. FIG. 89. Testing for Specific Volume. the vapor begins to superheat and the pressure becomes less than in B, which is still evaporating, so that the mercury-column levels separate. At this moment the steam in A is dry, its volume is known, and its weight, from which its specific volume at that tem- perature is readily found. The results from these experiments are shown by the curves of Fig. 90, where the curve to the left shows the rise in temperature and the curve to the right the decrease in specific volume as the absolute pressure (at mospheric-f pressure above atmospheric) increases. The total heat of evaporation is the quantity of heat required to raise the temperature of water from freezing-point to boiling- point and just convert it into steam. Regnault investigated the 316 AMERICAN GAS-ENGINEERING PRACTICE. total heat of steam in an apparatus shown in Fig. 91, consisting in a steam-boiler from which steam was taken through c into a coil, A, immsrsed in water connected with a bulb, B, in which the pres- sure could be regulated by the pump shown, and measured by the mercury column as shown in Fig. 88. Thermometers showed the temperatures of steam and cooling-water. From his experiments Regnault found that the total heat was equal to 1092+0.3 (-32). By deducting the sensible heat, t 32, the latent heat remained 800 200 TEMPERATURE FAH. VOL. 1 LB WT. FIG. 90. Relation of Pressure, Temperature, and Volume of Saturated Steam. as 1092-0.7 (/-32). To find a formula applicable to any tem- perat-ure for saturated steam above or below 212 deg. this formula becomes L=966-0.7(Z-212) = 1115-0.7$. STEAM. 317 In condensing steam the heat lost by the steam equals the heat gained by the water. Suppose the temperature of exhaust-steam o FIG. 91. Testing for Total Heat in Steam. FIG. 92. Graphical Diagram showing Distribution of "Work. to be 193 deg. F., that of the condensing water on entering 60 deg. and at exit 120 de'., then 966-0.7(212- 193) + (193- 120) = ^(120-60), W=17.53 Ibs. 318 AMERICAN GAS-ENGINEERING PRACTICE. Work in Steam. When steam is formed it occupies a relatively much greater volume than the water from which it had been formed; this expansion could take place only against the resistance of material previously occupying that space, and work is therefore done. This is illustrated in Fig. 92. where one pound of water is supposed to be heated in the tube having a piston above it of 1 square foot area. The steam pushes it upward against one atmos- phere, or 14.7 Ibs. per sq. in., or 14.7X144 = 2116.8 Ibs. As 1 cu. ft. of water weighs 62.5 Ibs. it will stand 1-^-62.5 = 0.016 foot high in the tube. The specific volume of 1 Ib. of steam at 212 deg. is 26.36 cu. ft., attained by doing 2116.8X26.36 = 55,799 ft.- Ibs. of work. The latent heat of steam absorbed 966 X 772 = 745,752 ft.-lbs. Taking from this 55,799 leaves 689,935 ft.-lbs. for internal work. Raising the temperature of water from 60 deg. to 212 deg. required 152X772=117,344 ft.-lbs. This may be summed up as Total work = [966 + 180- (60 -32)]772= 863,096 ft.-lbs. Thus 2. 1 parts of the work went to raise the temperature of the water 12.36 to internal work of changing water into steam and 1 part to external work of raising the piston or expansion. In the diagram let OA be 26.36 and OB 2116.8 Ibs.; then the shaded rectangle will represent external work. Make OD and DE 12.36 and 2.1 times OB respectively; the rectangle OD arid DG will rep- resent internal work and sensible heat respectively. The shaded area represents only useful work. The efficiency of steam-for- mation work therefore is 55,799^863,096 = 0.0646. Using these figures, let us take the example of a triple-expansion engine operat- ing with steam at 160 Ibs. gage pressure, or 160 + 14.7=174.7 Ibs. absolute pressure. Thence we have Specific volume of steam, cu. ft 2.5 Load on piston, 144X 174.7 Ibs 25,156.0 External work, 2.5X25,156 Ibs 62,890.0 Temperature of steam, deg. F 370.0 Latent heat, [966 -0.7 (370- 212)] X 772 ft.-lbs 660,369.0 Internal work, 660,369-62,890 ft, -Ibs 597,479.0 Raising temperature of water, (370-60)772 ft.-lbs 239,320.0 Total work, 62,890 + 597,479 + 239,320 ft.-lbs 899,689.0 -^~ . - , external work 62,890 Efficiency of steam = . . . -, = nn 1on =Q-Q7, total work 899,189 which shows that high-pressure steam is not more economical than low-pressure steam, weight for weight. Specific Heat. The relative quantity of heat required to raise the temperature of a substance 1 deg. F., as compared with water, STEAM 319 is termed its specific heat. As applied to gases it refers to two con- ditions constant volume and constant pressure, the temperature varying in both cases. As 1 cu. ft. of air weighs 0.0803 lb., 1 Ib. will occupy 12.4 cu. ft. at 1 atmosphere pressure and 32 deg. F. If it is heated to 212 deg. F., a rise of 180 deg. F., the increase in volume will be (180-^-492)12.4 = 4.54 cu. ft., which represents the rise of the piston in Fig. 92 against 2116.8 Ibs. ' The external work will therefore be 2116.8X12.4 = 9510.27 ft.-lbs. The specific heat of gases at constant pressure is 0.2375; thus the heat absorbed in raising the temperature of the air 180 deg. will be 180X0.2375 = 42.75 B.t.u. = 33,003 ft.-lbs. The difference, which is internal work, will therefore be 33,003-9510.27 = 23,492.75 ft.-lbs. = 30.43 B.t.u. Therefore the specific heat, constant volume, = 30.43-^180 = 0.1672 B.t.u., or, more correctly, 0.1686 B.t.u. The ratio of specific heats will therefore be 0.2375^0.1686= lAOS=y. When specific heats are represented in foot-pounds the symbols K p and K 9 may be used. According to Regnault's law the specific heat of a gas at con- stant pressure is the same at all temperatures. Suppose a gas to be heated under the constant pressure P, its volume being increased from V\ to V 2 and the absolute temperature rising from T l to T 2 , then the External work=P(7 2 -F ] ) = c(7 7 2 -7 7 1 ) ; Total " = K P (T 2 -T 1 ), Internal " =K p (T 2 -7 7 1 -c(7 7 2-r 1 ). Since only internal work is done when gas is heated at constant volume, C= Kp K v . Note that the internal work K v (T 2 Ti) may be either positive, negative, or nothing. Superheated Steam. By experiment K p = 370.56 ft.-lbs. Steam behaves like a perfect gas a few degrees above its saturation point, K p being practically a regular quantity. The ratio of the specific volumes of air to superheated steam is 0.622, and the constant C for steam equals the constant C for air divided by 0.622 or 85.5. Therefore 0=^-^=85.5, # = 370.56 -85.5 =285.06 ft.-lbs., K p 370.56 320 AMP:RICAN GAS-ENGINEERING PRACTICE. Expansion Curves. The hyperbola illustrating Boyle's law is shown in Fig. 93, and expresses the relation PV=C. FIG. 93. Hyperbolic Expansion Curve. FIG. 94. Expansion Area. Another expansion curve has the formula PV n =C, the exponent n changing with the material. The shaded area shows the work done during expansion, Fig. 94, and could be measured, but since the curve has a definite formula its area may be found by the formula ~. This of course requires the use of a table of hyperbolic logarithms. The area of the curve having the formula PV n =C is Area= rc-1 An isothermal curve follows the law of Boyle, the heat trans- formed into work during expansion being supplied so that the FIG. 95. Expansion Curves. FIG. 96. Compression Curves. temperature remains constant. If no heat is supplied, the curve will fall below the hyperbola as shown in Fig. 95. In compression STEAM. 321 the curve would rise above the isothermal as the gas becomes heated by work done upon it, as shown in Fig. 96. The value of the exponent n for the adiabatic expansion curve is thus developed : Area of curve = PlVl ^ 2 = -^ (T 2 - Tfi = external work. 71 1 71 J. Total work = internal work + external work Since no heat is added nor abstracted in adiabatic expansion this last expression is equal to zero; since the factor (T 2 TI) is tangible, nK v K p =0 and n=-^=y, A r and PVy=C is the general equation for adiabatic expansion. External work is done at the expense of the heat in the gas. Therefore, in adia- batic expansion P 2 V 2 y= P l VS, P 2 V 2 V 2 -i = P l V, TV-i, (FA^" 1 /FA^" 1 vj = cT *= cT \v 2 ) ' (rr \y-l /T.\ 0.408 il) , or Ti-T for air. 322 AMERICAN GAS-ENGINEERING PRACTICE. The formula thus far developed may now be collected: Isothermal expansion, PV = C, .,. , ,. ,-. T7< ( y= 1.408 for air Adiabatic PVy=C [ y = 1>3 forsup Saturated steam expansion, PV^=C (Rankine) = 475, Adiabatic " " p 71.235 = Q (Zeuner) , PV=C (Rarjkine), superheated steam expansion, PF 1 - 3 = C. These adiabatic curves represent the expansion of steam in a cylinder under good conditions. As shown in Fig. 97, all start- FIG. 97. Curves Compared. ing at the same point, the hyperbolic curve lies highest and the adiabatic for air lowest. By consulting Fig. 98 it will be seen that AB is the curve for dry steam; if V is decreased by compression at constant tempera- FIG. 98. Curves of Wet and Dry Steam. ture the steam becomes wet, but if V is increased the steam becomes superheated and has the formula PV l - 135 =C. Tables I and II give the properties of dry saturated steam and facts connected with steam generation. Table II gives the properties of dry saturated steam for differ- ences of 1 Ib. per sq. in. pressure and ranges usual in steam- boiler practice. STEAM. 323 I. PROPERTIES OF SATURATED STEAM. Abso- lute Pres- sure. Gage Pressure. Temper- ature F. Weight in 'ounds per Cubic Foot of Steam. Volume in Cubic Feet of One Pound of Steam. Total Heat above 32 F. Latent Heat, Heat- units. In the Water, Heat- units. In the Steam, Heat- units. 1 -27.9 102.1 .003 334.23 70.09 1113.1 1043.0 5 -19.7 162.3 .014 72.50 130.7 1131.4 1000.7 10 - 9.6 193.2 .026 37.80 161.9 1140.9 979.0 14.7 0. 212.0 .038 26.36 180.9 1146.6 965.7 15 .3 213.0 .039 25.87 181.9 1146.9 965.0 20 5.3 227.9 .050 19.72 197.0 1151.5 954.4 25 10.3 240.0 .063 15.99 209.3 1155.1 945.8 30 15.3 250.2 .074 13.48 219.7 1158.3 938.9 35 20.3 259.2 .086 11.66 228.8 1161.0 932.2 40 25.3 267.1 .097 10.28 236.9 1163.4 926.5 45 30.3 274.3 .109 9.21 244.3 1165.6 921.3 50 35.3 280.9 .120 8.34 251.0 1167.6 916.6 55 40.3 286.9 .131 7.63 257.2 1169.4 912.3 60 45.3 292.5 .142 7.03 262.9 1171.2 908.2 65 50.3 297.8 .153 6.53 268.3 1172.8 904.5 70 55.3 302.7 .164 6.09 273.4 1174.3 900.9 75 60.3 307.4 .175 5.71 278.2 1175.7 897.5 80 65.3 311.8 .186 5.37 282.7 1177.0 894.3 85 70.3 316.0 .197 5.07 287.0 1178.3 891.3 90 75.3 320.0 .208 4.81 291.2 1179.6 888.4 95 80.3 323.9 .219 4.57 295.1 1180.7 885.6 100 85.3 327.6 .230 4.36 298.9 1181.8 882.9 110 95.3 334.5 .251 3.98 306.1 1184.0 877.9 120 105.3 341.0 .272 3.67 312.8 1185.9 873.2 130 115.3 347.1 .294 3.41 319.1 1187.8 886.7 140 125.3 352.8 .315 3.18 325.0 1189.5 864.6 150 135.3 358.2 .336 2.98 330.6 1191.2 860.6 160 145.3 363.3 .357 2.80 335.9 1192.7 856.9 170 155.3 368.2 .378 2.65 340.9 1194.2 853.3 180 165.3 372.8 .398 2.51 345.8 1195.7 849.9 190 175.3 377.3 .419 2.39 350.4 1197.0 846.6 200 185.3 381.6 .440 2.27 354.9 1198.3 843.4 210 195.3 385.7 .461 2.17 359.2 1199.6 840.4 220 205.3 389.7 .485 2.06 362.2 1200.8 838.6 230 215.3 393.6 .506 1.98 366.2 1202.0 835.8 240 225.3 397.3 .527 1.90 370.0 1203.1 833.1 250 235.3 400.9 .548 1.83 373.8 1204.2 830.5 300 285.3 417.4 .651 1.535 390.9 1209.2 818.3 400 385.3 444.9 .857 1.167 419.8 1217.7 797.9 500 485.3 467.4 1.062 .942 443.5 1224.5 781.0 600 585.3 486.9 1.266 .790 464.2 1230.5 766.3 700 685.3 504.1 1.470 .680 482.4 1235.7 753.3 800 785.3 519.6 1.674 .597 498.9 1240.3 741.4 900 885.3 533.7 1.878 .532 514.0 1244.7 730.6 950 935.3 540.3 1.980 .505 521.3 1246.7 725.4 1000 985.3 546.8 2.082 .480 528.3 1248.7 720.3 324 AMERICAN GAS-ENGINEERING PRACTICE. II. PROPERTIES OF SATURATED STEAM. Absolute Pressure per Square Inch. Temper- atures. Total Latent Heat of Steam from Water Supplied Water Heat of Steam (to Raise Tempera- ture of Water from 32 F.). Total Heat of One Pound of Steam from Water Supplied at 32 F. Density or Weight of One Cubic Foot of Steam. Volume of One Pound of Steam. Relative Volume, or Cubic Feet of Steam from One Cubic Foot at 32 F. of Water. Lbs. Fahr. B.t.u. B.t.u. B.t.u. Lbs. Cu. Ft. Rel. Vol. 122 342 .4 872.8 313.0 1185.8 0.2781 3.595 224.2 123 343.0 872.3 313.7 1186.0 .2803 3.567 222.4 124 343.6 871.9 314.3 1186.2 .2824 3.541 220.8 125 344.2 871.5 314.9 1186.4 .2846 3.514 219.1 126 344.8 871.1 315.5 1186.6 .2867 3.488 217/5 127 345.4 870.7 316.1 1186.8 .2889 3.462 215.8 128 346.0 870.2 316.7 1186.9 .2910 3.436 214.3 129 346.6 869.8 317.3 1187.1 .2931 3.411 212.7 130 347.2 869.4 317.9 1187.3 .2951 3.388 211.3 131 347.8 869.0 318.5 1187.5 .2974 3.362 209.7 132 348.3 868.6 319.0 1187.6 .2996 3.338 208.1 133 348.9 868.2 319.6 1187.8 .3017 3.315 206.7 134 349.5 867.8 320.2 1188.0 .3038 3.291 205.2 135 350.1 867.4 320.8 1188.2 .3060 3.268 203.8 136 350.6 867.0 321.3 1188.3 .3080 3.246 202.4 137 351.2 866.6 321.9 1188.5 .3102 3.224 201.0 138 351.8 866.2 322.5 1188.7 .3123 3.201 199.6 139 352.4 865.8 323.1 1188.9 .3145 3.180 198.3 140 352.9 865.4 323.6 1189.0 .3166 3.159 197.0 141 353.5 865.0 324.2 1189.2 .3187 3.138 195.6 142 354.0 864.6 324.8 1189.4 .3209 3.117 194.3 143 354.5 864.2 325.4 1189.6 .3230 3.096 193.1 144 355.0 863.9 325.8 1189.7 .3251 3.076 191.8 145 355.6 863.5 326.4 1189.9 .3272 3.056 190.6 146 356.1 863.1 326.9 1190.0 .3293 3.037 189.4 147 356.7 862.7 327.5 1190.2 .3315 3.017 188.1 148 357.2 862.3 328.0 1190.3 .3336 2.998 186.9 149 357.8 861.9 328.6 1190.5 .3357 2.979 185.7 150 358.3 861.5 329.2 1190.7 .3378 2.960 184.6 151 359.0 861.1 329.8 1190.9 .3400 2.941 183.4 152 359.5 860.7 330.3 1191.0 .3421 2.923 182.2 153 360.0 860.4 330.8 1191.2 .3442 2.905 181.2 154 360.5 860.0 331.4 1191.4 .3463 2.887 180.0 155 361.1 859.6 331.9 1191.5 .3484 2.870 179.0 156 361.6 859.2 332.5 1191.7 .3505 2.8f3 177.9 157 362.1 858.9 332.9 1191.8 .3527 2.836 176.8 158 362.6 858.5 333.5 1192.0 .3548 2.818 175.7 159 363.1 858.1 334.0 1192.1 .3569 2.802 174.7 160 363.6 857.8 334.5 1192.3 .3590 2.785 173.7 165 366.0 856.2 336.7 1192.9 .3696 2.706 168.7 170 368.2 854.5 339.2 1193.7 .3801 2.631 164.1 175 370.8 852.9 341.5 1194.4 .3905 2.59 159.7 180 372.9 851.3 343.8 1195.1 .4011 2.493 155.5 185 375.3 849.6 346.2 1195.8 .4115 2.430 151.5 190 377.5 848.0 348.5 1196.5 .4220 2.370 147.8 195 379.7 846.5 350.7 1197.2 .4324 2.313 144.2 200 381.7 845.0 352.8 1197.8 .4419 2.263 141.1 STEAM. 325 The rate at which stearn is evaporated in a given boiler will depend to a considerable extent upon the temperature at which the feed-water enters it. The table on page 331 will illustrate this fact clearly and demonstrates the value of preheating feed-water in an economizer or otherwise. B. STEAM-BOILER PRACTICE. Fuels. There is a large variety of fuels adapted for steam- raising. Possibly the first hi order of precedence is wood, which is equal to 40 per cent, of its weight of coal, or 2.5 Ibs. of wood equal 1 Ib. of coal. Some say 2.25 Ibs. of dry wood equal 1 Ib. of good coal. The table here presented gives a comparison of some of the usual fireplace woods. .-.": ...... Weight,Lb, <*$ One cord of hickory or hard maple 4500 2000 " " " white oak 3850 1711 " " " beech, red oak, black oak 3250 1445 " " " poplar, chestnut, elm 2350 1044 " " "pine 2000 890 Sharpless assumes a coal equivalent of about 10 per cent, less than that given above. Coal and other solid fuels vary considerably in composition, as shown by these average examples: ANALYSES OF FUELS. Water. Volatile Matter. Fixed Carbon. Ash. Sulphur. Anthracite (mixed). . . Semi-bituminous Bituminous 3.40 1.00 1.20 3.80 20.00 32.50 83.80 73.00 60.00 8.40 5.00 5.30 0.60 1.00 1 00 T ignite . 22.00 32.00 37.00 9 00 ~*oke . 89 . 00 10 00 80 Carbon. Hydrogen. Oxygen. Nitrogen. Ash. Vood dry 50 6 41 1 2 Charcoal ... .... 75 5 2 5 12 1 Peat, dry and ash-free 58.0 5.7 35.0 1.2 326 AMERICAN GAS-ENGINEERING PRACTICE. WEIGHT PER CUBIC FOOT OF COAL AND COKE. Lbs. per Storage for Cu. Ft. Long Ton. Anthracite coal, market sizes, loose 52-56 40-43 cu. ft. Anthracite coal, market sizes, moderately shaken " 56-60 Anthracite coal, market size, heaped bushel, loose 77-83 Bituminous coal, broken, loose 47-52 43-48 " Bituminous coal , moderately shaken .... 50-56 Bituminous coal, heaped bushel 70-78 Dry coke 23-32 80-97 " Dry coke, heaped bushel (average 38).. . 35-42 HEATING VALUE OF SOME FUELS. B.t.u. Peat, Irish, perfectly dried, ash 4 per cent 10,200 Peat, air-dried, 25 per cent, moisture, ash 4 per cent 7,400 Wood, perfectly dry, ash 2 per cent 7,800 Wood, 25 per cent, moisture 5,800 Tanbark, perfectly dry, 15 per cent, ash 6,100 Tanbark, 30 per cent, moisture 4,300 Straw, 10 per cent, moisture, ash 4 per cent 5,450 Straw, dry, ash 4 per cent 6,300 Lignites 11,200 The above are approximate figures, for on such materials qualities are very variable. Coal ard coke are often measured by the bushel. The stand- ard bushel of the American Gaslight Association is 18J in. diam. and 8 in. deep = 2150.42 cu. i~. A Iraped bushel is the samo plus a ccne 19 in. diam. and 6 in. high, or a total of 2747.7 cu. in. An ordinary heaped bushel = 1J struck bushels = 2688 cu.in. = 10 gallons dry measure. Crude petroleum = 7.3 Ibs. per gallon. ANTHRACITE-COAL SIZES. Size and Name. Chestnut Pea No. 1 buckwheat "' 2 " or rice. .. "3 " or barley. Dust. . Through a Round Hole. \\ inches diameter Over a Round Hole. inches diameter STEAM. 327 Comparative Values of Fuel. The following table shows the relative values of fuel used in furnace practice, either coal or coke, with different percentages of ash, showing the influence of the latter. h |u F 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 98 Percentage of Ash. 2% 3% 4% 5% 6% 7% 8% 9% $2.81: 2.86 2.90 2.93 2.96 3.00 3.04 10% 11% $2.79 2.83 2.87 2.88 2.92 2.96 3 00 12% $2.77 2.81 2.85 2.86 2.90 2.94 2.98 13% $2.76 2.79 2.84 2.84 2.88 2.92 14% $2.74 2.78 2.82 $2.83 2.88 2.91 2.95 2.97 3.02 306 2.80 2.84 2.88 2.90 2.94 2.98 302 $2.93 2.97 2.99 3.04 308 S3.01 3.06 3.10 $3.17 3.21 3.25 3.3] 3.35 3.39 3.42 3.45 3.50 3.54 3.57 3.6] 3.15 3.19 3.23 3.29 3.33 3.37 3.39 3.43 3.48 3.52 3.13 3.17 3.21 3.26 3.30 3.34 3.36 3.41 3.10 3.14 3.18 3.23 3.27 3.32 3.33 3.0F 3.12 3.16 3.20 3.24 3.29 3.06 3.10 3.14 3.18 3.04 3.08 3.12 3.02 3.06 $3^33 3.37 3.41 3.44 3.47 3.51 3.56 3.59 3.64 $3^54 3.58 3.63 3.68 $3.46 3.49 3.52 3.57 3.61 3.66 Approximately 1.43 to 1.54 Ibs. of petroleum of 7.3 Ibs. per gallon equals 1 Ib. best soft coal. It requires about 4 per cent, of the steam generated to operate the atomizing oil spray for a boiler, this being preferred to an air spray. Probably 35,000 cu. ft. of natural gas will be equal in heating value to a ton of coal. Water Supply. The water-pipe should be ample in size, so as not to restrict the flow should incrustations form. Bends in the pipe also reduce the delivery. Weisbach gives this formula for the loss due to friction: T72 f- 64.4' 172 P=f = where P=loss in pressure, Ibs. per sq. in.; V= velocity of flow in ft. per second; /= coefficient of friction found in the following table for various angles of bend, A: A.. 20 40 45 60 80 90 100 110 120 130 /..0.02 0.06 0.079 0.158 0.32 0.426 0.546 0.674 0.806 0.934 OF THE UNIVERSITY OF 328 AMERICAN GAS-ENGINEERING PRACTICE. This applies to such short bends as are found in ordinary fittings, such as 90 and 45 ells, tees, etc. A globe valve will produce a loss about equal to two 90 bends, a straightway valve about equal to one 45 bend. To use the above formula find the velocity V from the table, square this speed, and divide the result by 64.4; multiply the quotient by the tabular value of F, corresponding to the angle of the turn A. For example, a 400-h.p. battery of boilers is to be fed through a 2-in. pipe. Allowing for fluctuations we figure 40 gallons per minute, making 244 feet per minute speed, equal to a velocity of 4.06 ft. per second. Suppose our pipe is in all 75 ft. long, we have from the second table on page 329, for 40 gallons per minute, 1.6 Ibs. loss; for 75 ft. we have only 75 per cent, of this, =1.2 Ibs. Suppose we have six right-angled ells, each giving F= 0.426. We have then 4.06X4.06= 16.48; divide this by 64.4 = 0.256. Multiply this by F= 0.426 lb., and as there are six ells, multiply again by 6, and we have 6X0.426X0.256=0.654. The total friction in the pipe is therefore 1.2+0.654 Ibs. per sq. in. If the boiler pressure is 100 Ibs. and the water-level in the boiler is 8 feet higher than the pump- suction level we have first 8X0.433 = 3.464 Ibs. The total pres- sure on the pump-plunger then is 100 + 3.464 + 1.854=105.32 Ibs. per sq. in. If in place of six right-angled ells we had used three 45 ells, they would have cost us only 3X0.079=0.237 lb.; 0.237X 0.256=0.061. The total friction head would have been 1.20+0.061 = 1.261 and the total pressure on the plunger 100+3.464 + 1.261 = 104.73 Ibs. per sq. in., a saving over the other plan of nearly 0.6 lb. To be accurate we ought to add a certain head in either case "to produce the velocity." But this is very small, being for velocities of: 2 0.027 3 0.061 4 0.108 5 0.168 6 0.244 8 0.433 10 0.672 12 and . 970 and 18 feet per sec. 2. 18 Ibs. per sq. in. Our results should therefore have been increased by about 0.11 Ibs. It is usual, however, to use larger pipes and thus to materially reduce the frictional losses. The weight of water varies with the temperature as given by the table by C. A. Smith on page 330. STEAM. 329 TABLE GIVING RATE OF FLOW OF WATER, IN FEET PER MINUTE, THROUGH PIPES OF VARIOUS SIZES, FOR VARYING QUANTITIES OF FLOW. Gallons Diamete ", Inches. per Minute. 1 1 H ii 2 Zi 3 4 5 218 122.5 78.5 54.5 30.5 19.5 13.5 7.6 10 436 245 157 109 61 38 27 15.3 15 653 367.5 235.5 163.5 91.5 58.5 40.5 23 20 872 490 314 218 122 78 54 30.6 25 1090 612.5 392.5 272.5 152.5 97.5 67.5 38.3 30 .... 735 451 327 183 117 81 46 35 857.5 549.5 381.5 213.5 136.5 94.5 53.6 40 980 628 436 244 156 108 61.3 45 .... 1102.5 706.5 490.5 274.5 175.5 121.5 69 50 785 545 305 195 135 76.6 75 1177.5 817.5 457.5 292.5 202.5 115 100 1090 610 380 270 153.3 125 762.5 487.5 337.5 191.6 150 915 585 405 230 175 1067.5 682.5 472.5 268.5 200 1220 780 540 306.6 LOSS IN PRESSURE DUE TO FRICTION. POUNDS PER SQUARE INCH FOR PIPE 100 FEET LONO. Gallons Dis- charged Diameter , Inches. per Minute. * 1 H 11 2 2| 3 4 5 3.3 0.84 0.31 0.12 10 13.0 3.16 1.05 0.47 0.12 15 28.7 6.98 2.38 0.97 20 50.4 12.3 4.07 1.66 0.42 25 78.0 19.0 6.40 2.62 0.21 0.10 30 .... 27.5 9.15 3.75 O.Q1 35 .... 37.0 12.4 5.05 40 .... 48.0 16.1 6.52 1.60 45 20.2 8.15 50 . . '. '. 24.9 10.0 2.44 0.81 0.33 0.09 75 56.1 22.4 5.32 1.80 0.74 100 39.0 9.46 3.20 1.31 0.33 125 14.9 4.89 1.99 150 21.2 7.0 2.85 0.69 175 28.1 9.46 3.85 200 37.5 12.47 5.02 1.22 330 AMERICAN GAS-ENGINEERING PRACTICE. WEIGHT OF WATER PER CUBIC FOOT AND HEAT-UNITS IN WATER BETWEEN 32 AND 212 F. Weight Weight Weight in in in Temp., Pounds Heat- Temp., Pounds Heat- Temp., Pounds Heat- Deg. F. per Cubic units. Deg. F. Cubic units. Deg. F. per Cubic units. Foot. Foot. Foot. 32 62.42 0.00 96 62.07 64.07 160 60.98 128.37 34 62.42 2.00 98 62.05 66.07 162 60.94 130.39 36 62.42 4.00 100 62.02 68.08 164 60.90 132.41 38 62.42 6.00 102 62.00 70.09 166 60.85 134.42 40 62.42 8.00 104 61.97 72.09 168 60.81 136.44 42 62.42 10.00 106 61.95 74.10 170 60.77 138.45 44 62.42 12.00 108 61.92 76.10 172 60.73 140.47 46 62.42 14.00 110 61.89 78.11 174 60.68 142.49 48 62.41 16.00 112 61.86 80.12 176 60.64 144.51 50 62.41 18.00 114 61.83 82.13 178 60.59 146.52 52 62.40 20.00 116 61.80 84.13 180 60.55 148.54 54 62.40 22.01 118 61.77 86.14 182 60.50 150.56 56 62.39 24.01 120 61.74 88.15 184 60.46 152.58 58 62.38 26.01 122 61.70 90.16 186 60.41 154.60 60 62.37 28.01 124 61.67 92.17 188 60.37 156.62 62 62.36 30.01 126 61.63 94.17 190 60.32 158.64 64 62.35 32.01 128 61.60 96.18 192 60.27 160.67 66 62.34 ^34. 02 130 61.56 98.19 194 60.22 162.69 68 62.33 36.02 132 61.52 100.20 196 60.17 164.71 70 62.31 38.02 134 61.49 102.21 198 60.12 166.73 72 62.30 40.02 136 61.45 104.22 200 60.07 168.75 74 62.28 42.03 138 61.41 106.23 202 60.02 170.78 76 62.27 44.03 140 61.37 108.25 204 59.97 172.80 78 62.25 46.03 142 61.34 110.26 206 59.92 174.83 80 62.23 48.04 144 61.30 112.27 208 59.87 176.85 82 62.21 50.04 146 61.26 114.28 210 59.82 178.87 84 62.19 52.04 148 61.22 116.29 212 59.76 180.90 86 62.17 54.05 150 61.18 118.31 88 62.15 56.05 152 61.14 120.32 90 62.13 58.06 154 61.10 122.33 92 62.11 60.06 156 61.06 124.35 94 62.09 62.06 158 61.02 126.36 STEAM. 331 Pure water at 62 deg. F. weighs 62.355 Ibs. per cu. ft., or 8 Ibs. per U. S. gallon; 7.48 gallons= 1 cu. ft. It takes 30 Ibs. or 3.6 gallons of boiler feed-water for each horse-power per hour. HEAT TRANSMITTED BY CONDENSER SURFACES PER SQUARE FOOT PER HOUR. Surface. B.t.u. Smooth vertical plane 406 Vertical plane with about 80% surface in ribs or cor- rugations 170 Smooth vertical pipe surface 480 Vertical tube with 67% of surface in corrugations. . . 221 Horizontal smooth tube or pipe 369 Horizontal tube with 67% of surface in corrugations 185 Note. This table is correct for steam of 15 to 22 Ibs. pres- sure ; for exhaust-steam reduce in proportion to temperature, except for corrugated and ribbed surfaces, which lose very rapidly for low steam temperatures. For hot water, 50 per cent, of the tabular numbers is approximately correct. PERCENTAGE OF SAVING FOR EACH DEGREE OF INCREASE IN TEM- PERATURE OF FEED-WATER HEATED. Initial Tempera- ture of Feed. Pressure of Steam in Boiler, Lbs. per Sq. In. above Atmosphere. 20 40 60 80 100 120 140 160 180 200 32 .0872 .0861 .0855 .0851 .0847 .0844 .0841 .0839 .0837 .0835 .0833 40 .0878 .0867 .0861 .0856 .0853 .0850 .0847 .0845 .0843 .0841 .0839 50 .0886 .0875 .0868 .0864 .0860 .0857 .0854 .0852 .0850 .0848 .0846 60 .0894 .0883 .0876 .0872 .0867 .0864 .0862 .0859 .0856 .0855 .0853 70 .0902 .0890 .0884 .0879 .0875 .0872 .0869 .0867 .0864 .0862 .0860 80 .0910 .0898 .0891 .0887 .0883 .0879 .0877 .0874 .0872 . 0870 .0868 90 .0919 .0907 .0900 .0895 .0888 .0887 .0884 .0883 . 0879 .0877 .0875 100 .0927 .0915 .0908 .0903 .0899 .0895 .0892 .0890 .0887 .0885 .0883 110 .0936 .0923 .0916 .0911 .0907 .0903 .0900 .0898 .0895 .0893 .0891 120 .0945 .0932 .0925 .0919 .0915 .0911 .0908 .0906 .0903 .0901 .0899 130 .0954 .0941 .0934 .0928 .0924 .0920 .0917 .0914 .0912 .0909 .0907 140 .0963 .0950 .0943 .0937 .0932 .0929 .0925 .0923 .0920 .0918 .0916 150 .0973 .0959 .0951 .0946 .0941 .0937 .0934 .0931 .0929 .0926 .0924 160 .0982 .0968 .0961 .0955 .0950 .0946 .0943 .0940 .0937 .0935 .0933 170 .0992 .0978 .0970 .0964 .0959 .0955 .0952 .0949 .0946 .0944 .0941 180 .1002 .0988 .0981 .0973 .0969 .0965 .0961 .0958 . 0955 .0953 .0951 190 .1012 .0998 .0989 .0983 .0978 .0974 .0971 .0968 .0964 .0962 .0960 200 .1022 .1008 .0999 .0993 .0988 .0984 .0980 .0977 .0974 .0972 .0969 210 .1033 .1018 .1009 .1003 .0998 .0994 .0990 .0987 .0984 .0981 .0979 220 .1029 .1019 .1013 .1008 .1004 .1000 .0997 .0994 .0991 .0989 230 .1039 .1031 .1024 .1018 .1012 .1010 .1007 .1003 .1001 .0999 240 . 1050 .1041 . 1034 .1029 .1024 .1020 .1017 .1014 .1011 .1009 250 .1062 .1052 .1045 .1040 .1035 .1031 .1027 .1025 .1022 .1019 332 AMERICAN GAS-ENGINEERING PRACTICE. MAXIMUM HEIGHT WATER CAN BE LIFTED BY SUCTION AT VARIOUS DISTANCES ABOVE SEA-LEVEL. Height Above Sea- level, in Feet. Average Barometric Pressure. Height of Lift, Feet. Inches. Lbs. per Sq. In. 30.00 14.7 33.9 100 29.89 14.6 33.8 200 29.78 14.6 33.7 300 29.68 14.5 33.6 400 29.57 14.5 33.5 500 29.46 14.4 33.3 600 29.35 14.4 33.2 700 29.25 14.3 33.1 800 29.14 14.3 32.0 900 29.04 14.2 32.9 1000 28.94 14.2 32.7 1250 28.67 14.1 32.4 1500 28.42 13.9 32.1 2000 27.91 13.7 31.6 2500 27.40 13.4 31.0 3000 26.92 13.2 30.4 3500 26.43 13.0 29.9 4000 25.96 12.7 29.4 4500 25.49 12.5 28.9 5000 25.02 12.3 28.3 6000 24.12 11.8 27.3 7000 23.28 11.4 26.3 8000 22.44 11.0 25.4 9000 21.64 10.6 24.5 10000 20.85 10.2 23.6 Note. The heights given above are for a perfect vacuum. In practice, pumps will ordinarily lift water about" eight-tenths the height given. CHIMNEYS. The " proportions of chimneys " vary very much according to the requirements. Every chimney should be large enough in cross-section to carry off the gases and high enough to produce sufficient draught to cause a rapid combustion. The object of a chimney being to carry off the waste gases, it naturally determines the amount of fuel that can be burnt per hour, and it is advisable to have invariably a good draught, as it can always be regulated by a damper. .Draught pressure is caused by the difference in weight between a column of hot gases in the chimney and a column of air of equal height and area outside the chimney. STEAM. 333 Formula for finding the force of draught in inches of water for any given chimney : 7.64 7.95 N where F = force of draught in inches of water; H = height of chimney in feet; TI = absolute temperature of chimney gases (t + 460) ; T 2 = " the external air ( t = temperature of chimney gases; ti= " " external air. Formula for finding the height of a chimney in feet for a given force of draught: /7.64 7.95V \ T, ~ Tj To find the maximum force of draught for any given chimney, the external air being 60 deg. F. and the heated column being 600 deg. F., multiply the height above the grate in feet by 0.0073, and the product is the force of draught expressed in inches of water. William Kent, in his " Mechanical Engineer's Pocket-book" (pages 734 and 736, 4th Revised Ed.), gives the following: " The sizes corresponding to the given commercial horse-powers are believed to be ample for all cases in which the draught areas through the boiler-flues and connections are sufficient, say rot less than twenty per cent, greater than the area of the chimney, and in which the draught between the boilers and chimney is not checked by long horizontal passages ard right-angled bends." Note that the figures in table p. 336 correspond to a coal con- sumption of 5 Ibs. coal per horse-power hour. This liberal allowance is made to cover the contingencies of poor coal being used, and of boilers being driven beyond their rated capacity. In large plants with economical boilers and engines, good fuel, and other favorable conditions, which will reduce the maximum rate of coal consumption at any one time to less than 5 Ibs. per h.p. per hour, the figures in the table may be multiplied by the ratio of five to the maximum expected coal consumption per horse-power per hour. Thus, with conditions which make the maximum coal consumption 2.5 Ibs. per hour, the chimney 300 ft. high X 12 ft. diameter should be sufficient for 6155X2= 12,310 h.p. The formula is based on the following data. Chimney Draught. According to the data of the Green Fuel Economizer Co.: 334 AMERICAN GAS-ENGINEERING PRACTICE. 1. The draught power of the chimney varies as the square root of the height. 2. The retarding of the ascending gases by friction may be considered as equivalent to a diminution of the area of the chimney, or to a lining of the chimney by a layer of gas which has no velocity. The thickness of this lining is assumed to be 2 ins. for all chimneys, or the diminution of area equal to the perimeter X 2 ins. (neglecting the overlapping of the corners of the lining). Let D= diameter in feet, J. = area, and E= effective area in square feet. or\ o _ For square chimneys, E=D 2 =A \ // A. For round chimneys, E= For simplifying calculations, the coefficient of V A may be taken as 0.6 for both square and round chimneys, and the formula becomes 3. The power varies directly as this effective area E. 4. A chimney should be proportioned so as to be capable of giving sufficient draught to cause the boiler to develop much more than its rated power, in case of emergencies, or to cause the com- bustion of 5 Ibs. of fuel per rated horse-power of boiler per hour. 5. The power of the chimney varying directly as the effective area E, and as the square root of the height H, the formula for horse-power of boiler for a given size of chimney will take the form h.p. = CM///, in which C is a constant, the average value of which, obtained by plotting the results obtained from numerous examples in practice, the author finds to be 3.33. The formula for horse-power then is h.p. = 3.33tfv#, or h.p. = If the horse-power of boiler is given, to find the size of chimney, the height being assumed, vH For round chimneys, diameter of chimney = diameter of E+4 ins. For square chimneys, side of chimney = v / # + 4 ins. If effective area E is taken in square feet, the diameter in inches STEAM. 335 is d= 13.54\/J + 4 ins. ; and the side of a square chimney in inches is s=12V / r +4 ins. If horse-power is given and area assumed, the height In proportioning chimneys the height is generally first assumed, with due consideration to the heights of surrounding buildings or hills near to the proposed chimney, the length of horizontal flues, the character of coal to be used, etc., and then the diameter required for the assumed height and horse-power is calculated by the formula or taken from the table. From these formula the table on page 336 has been calculated, assuming that for each horse-power 5 Ibs. of coal are burned per hour. WEIGHT OF COAL AND STORAGE. 21 bushels coke=l cubic yard (English). 72 ". -1 ton. Cannel coal, 45 cubic feet per ton. Coal store should equal six weeks' supply. SPACE OCCUPIED PER TON OF DIFFERENT COALS. Weight per Cubic Foot. Average anthracite = 39 cubic feet 58.25 Ibs. bituminous =43 " " 53 " Navy allowance for storage = 48 ' ' " COKE. 23 to 32 Ibs. per cu. ft. Ton occupies from 80 to 97 cu. ft. Coal in coking swells in bulk from 25 to 50 ptr cent. Coke and coal will evaporate about equal amounts of water and about twice the amount of an equal weight of wood. COAL ANTHRACITE . Actual weight about 93.5 Ibs. per cu. ft. Broken (average) 52 to 60 Ibs. per cu. ft. Ton occupies from 40 to 43 cu. ft. COAL BITUMINOUS. Actual weight about 84 Ibs. per cu. ft. Broken (average) 47 to 56 Ibs. per cu. ft. About 70 to 78 Ibs. per bu. Ton occupies 43 to 48 cu. ft. Coal when broken increases in bulk up to 75 per cent. 336 AMERICAN GAS-ENGINEERING PRACTICE OOCMT^t^CxMiO r-i r-i O COCOOCOt^C^T-Hi-* (MJMCOCOCOTfiOCO coco T icjicoscotoo:' < ^O oc ^""1 "^ t^* o ^r oc co co -00 OOO OOi OS 1-1 Tf OS CO *Ol>O TJH o CO i i Tf b- i ^ (M OS $< t O ^* CO t-SoOSQNNO *O t^ OS i"H CO ^O t s ^ O CO *^' OS C^ OS t^* i i W 1C OS -tf OS T-I Tfi t>. TJI CO (M T CO O OS OS *~^ ^ ^ t^ OS co i ' os r i irj CM co OC 1 co oo rf ^O OS O^J t^ CD t^* OS C^l t^-* CO i^ i i I-H M N09^df^gOQO4 -O5O5CMO5 00 00 Ci *C Tfi 1*5 tOTj i co OS-f0 00 TfH C^ CM tO !M co >O 1> OS -* Effective A = A-0.6 Sq. Ft. t^t^-OOOOOOOOt^t^ CO^t 1 ' iGOCOOOCOCO OS^COCO'COiMOOfM 'CD t^ococdd'oos-t cc6^ooocoosco r-t i i F-i .00 OCO'MOO't'O'M'ti a OS O STEAM. FLUE AREA REQUIRED FOR THE PASSAGE OF A GIVEN VOLUME OF AIR AT A GIVEN VELOCITY. Volume in Cubic Feet per Minute. Velocity in Feet per Minute. 300 400 500 600 700 800 900 1000 1100 1200 100 48 36 29 24 21 18 16 14 13 12 125 60 45 36 30 26 23 20 18 16 15 150 72 54 43 36 31 27 24 22 20 18 175 84 63 50 42 36 32 28 25 23 21 200 96 72 58 48 41 36 32 29 26 24 225 108 81 65 54 46 41 36 32 29 27 250 120 90 72 60 51 45 40 36 33 30 275 132 99 79 66 57 50 44 40 36 33 300 144 108 86 72 62 54 48 43 39 36 325 156 1x7 94 78 67 59 52 47 43 39 350 168 126 101 84 72 63 56 50 46 42 375 180 135 108 90 77 68 60 54 49 45 400 192 144 115 96 82 72 64 58 52 48 425 204 153 122 102 87 77 68 61 56 51 450 216 162 130 108 93 81 72 65 59 54 475 228 171 137 114 98 86 76 68 62 57 500 240 180 144 120 103 90 80 72 65 60 525 252 189 151 126 108 95 84 76 69 63 550 264 198 158 132 113 99 88 79 72 66 575 276 207 166 138 118 104 92 83 75 69 600 288 216 173 144 123 108 96 86 79 72 625 300 225 180 150 129 113 100 90 82 75 650 312 234 187 156 134 117 104 94 85 78 675 324 243 194 162 139 122 108 97 88 81 700 336 252 202 168 144 126 112 101 92 84 725 348 261 209 174 149 131 116 104 95 87 750 360 270 216 180 154 135 120 108 98 90 775 372 279 223 186 159 140 124 112 101 93 800 384 288 230 192 165 144 128 115 105 96 825 396 297 238 198 170 149 132 119 108 99 850 408 306 245 204 175 153 136 122 111 102 875 420 315 252 210 180 158 140 126 115 105 900 432 324 259 216 185 162 144 130 118 108 925 444 333 266 222 190 167 148 133 121 111 950 456 342 274 228 195 171 152 137 124 114 975 468 351 281 234 201 176 156 140 128 117 1000 480 360 288 240 206 180 160 144 131 121 338 AMERICAN GAS-ENGINEERING PRACTICE. FLUE AREA REQUIRED FOR THE PASSAGE OF A GIVEN VOLUME OF AIR AT A GIVEN VELOCITY (Continued). Volume in Cubic Feet per Minute. Velocity in Feet per Minute. 1300 1400 1500 1600 1700 1800 1900 2000 2100 100 11 10 9.6 9 8.5 8 7.6 7.2 6.9 125 14 13 12 11.3 10.6 10 9.5 9 8.6 150 16 15 14.4 13.5 12.7 12 11.4 10.8 10.3 175 19 18 16.8 15.8 14.8 14 13.3 12.6 12 200 22 21 19.2 18 16.9 16 15.2 14.4 13.7 225 25 23 21.6 20.3 19.1 18 17.1 16.2 15.6 250 28 26 24 22.5 21.2 20 19 18 17.1 275 30 28 26.4 24.8 23.3 22 21.8 19.8 18.9 300 33 31 28.8 27 25.4 24 22.7 21.6 20.6 325 36 33 31.2 29.3 27.5 26 24.6 23.4 22.3 350 39 36 33.6 31.5 29.6 28 26.5 25.2 24 375 42 39 36 33.8 31.8 30 28.4 27 25.7 400 44 41 38.4 36 33.9 32 30.3 28.8 27.4 425 47 44 40.8 38.3 36 34 32.2 30.6 29.1 450 50 46 43.2 40.5 38.1 36 34.1 32.4 30.9 475 53 49 45.6 42.8 40.2 38 36 34.2 32.6 500 55 51 48; 45 42.4 40 37.9 36 34.3 525 58 54 50.4 47.3 44.5 42 39.8 37.8 36 550 61 57 52.8 49.5 40.6 44 41.7 38.6 37.7 575 64 59 55.2 51.8 48.7 46 43.6 41.4 39.4 600 66 62 57.6 54 50.8 48 45.5 43.2 41.1 625 69 64 60 56.3 52.9 50 47.4 45 42.9 650 72 67 62.4 58.5 55.1 52 49.3 46.8 44.6 675 75 69 64.8 60.8 57.2 54 51.2 48.6 46.3 700 78 72 67.2 63 59.3 56 53.1 50.4 48 725 80 75 69.6 65.3 61.4 58 55 52.2 49.7 750 83 77 72 67.5 63.5 60 56.9 54 51.4 775 86 80 74.4 69.8 65.6 62 58.8 56.3 53.1 800 89 82 76.8 72 67.8 64 60.6 57.6 54.9 825 91 85 79.2 74.3 69.9 66 62.5 59.4 56.6 850 94 87 81.6 76.5 72 68 64.4 61.2 58.4 875 97 90 84 78.8 74 70 67.3 63 60 900 100 93 86.4 81 76.2 . 72 68.2 64.8 61.7 925 103 95 88.8 83.3 78.4 74 70.1 66.6 63.4 950 105 98 91.2 85.5 80.5 76 72 68.4 65.1 975 108 100 93.6 87.8 82.6 78 73.9 70.2 66.8 1000 111 103 96 90 84.7 80 75.8 72 68.7 STEAM 339 FLUE AREA REQUIRED FOR THE PASSAGE OF A GIVEN VOLUME OF AIR AT A GIVEN VELOCITY (Continued). Volume in Velocity in Feet per Minute. Cubic I 1 eet per Minute. 2200 2300 2400 2600 2700 2800 2900 3000 3100 100 6.6 6.3 6 5.5 5.3 5.1 5 4.8 4.6 125 8.2 7.8 7.5 6.9 6.7 6.4 6.2 6 5.8 150 9.8 9.4 9 8 8 7.7 7.5 7.2 7 175 11.5 11 10.5 9.7 9.3 9 8.7 8.4 8.1 200 13.1 12.5 12 11.1 10.7 10.3 9.9 9.6 9.3 225 14.7 14.1 13.5 12.5 12 11.6 11.2 10.8 10.4 250 16.4 15.7 15 13.9 13.3 12.9 12.4 12, 11.6 275 18 17.2 16.5 15.2 14.7 14.1 13.7 13.2 12.8 300 19.6 18.8 18 16.6 16 15.4 14.9 14.4 13.9 325 21.3 20.6 19.5 18 17.3 16.7 16.1 15.6 15.1 350 22.9 21.9 21 19.4 18.7 18 17.4 16.8 16.3 375 24.5 23.5 22.5 20.8 20 19.3 18.6 18 17.4 400 26.2 25 24 22.2 21.3 20.6 19.8 19.2 18.6 425 27.8 26.6 25.5 23.5 22.7 21.9 21.1 20.4 19.7 450 29.5 28.2 27 24.9 24 23.1 22.3 21.6 20.9 475 31.1 29.7 28.5 26.3 25.3 24.4 23.6 22.8 22.1 500 32.7 31.3 30 27.7 26.7 25.7 24.8 24 23.2 525 34.4 32.9 31.5 29.1 28 26.9 25 25.2 24.4 550 36 34.4 33 30.5 29.3 28.3 27.3 26.4 25.5 575 37.6 36 34.5 31.9 30.7 29.6 28.5 27.6 26.7 600 39.3 37.6 36 33.2 32 30.8 29.8 28.8 27.8 625 40.9 39.1 37.5 34.6 33.3 32.1 31 30 29 650 42.5 40.7 39 36 34.7 33.4 32.2 31.2 30.2 675 44.1 42.3 40.5 37.5 36 34.7 33.5 32.4 31.3 700 45.8 43.8 42 38.8 37.3 36 34.7 33.6 32.5 725 47.4 45.4 43.5 40.2 38.7 37.3 36 34.8 33.6 750 49.1 47 45 41.5 40 38.6 37.2 36 34.8 775 50.7 48.5 46.5 42.9 41.3 39.9 38.5 37.2 36 800 52.4 50.1 48 44.3 42.7 41.2 39.7 38.4 37.1 825 54 51.7 49.5 45.7 44 42.4 40.9 39.6 38.3 850 55.6 53.2 51 47.1 45.3 43.7 42.2 40.8 39.4 875 57.3 54.8 52.5 48.5 46.7 45 43.4 42 40.6 900 58.9 56.3 54 49.9 48 46.3 44.6 43.2 41.8 925 60.5 57.9 55.5 51.3 49.3 47.6 46 44.4 42.9 950 62.2 59.5 57 52.6 50.7 48.8 47.1 45.6 44.1 975 63.8 61.0 58.5 54 52 50.2 48.4 46.8 45.3 1000 66 62.6 60 55.4 53.3 51.4 49.6 48 46.4 340 AMERICAN GAS-ENGINEERING PRACTICE. PERCENTAGE OP THE TOTAL HEAT VALUE OF THE COAL REPRESENTED BY THE VARYING AMOUNTS OF CO2 IN FLUE-GAS.* * CO 9 , Heat Value of Coal, Per Cent. Per Cent. 2 5.3 3 8.0 4 10.8 5 13.7 6 16.6 7 19.6 8 23.0 9 26.5 10.. .30.0 * From H. H. Campbell's work on the Manufacture of Iron and Steel, page 243. CHAPTER XXI. MATHEMATICAL TABLES. DIMENSIONS OF CIRCLES, POWERS, AND ROOTS. Number or Diameter. Circum- ference. Circular Area. Square. Cube. Square Root. Cube Root. 1 3.1416 0.7854 1 1 1.000 1.000 2 6.2832 3.1416 4 8 1.414 1.259 3 9.4248 7.0686 9 27 1.732 1.442 4 12.57 12.57 16 64 2.000 1.587 5 15.71 19.63 25 125 2.236 1.709 6 18.85 28.27 36 216 2.449 1.817 7 21.99 38.48 49 343 2.645 1.912 8 25.13 50.27 64 512 2.828 2.000 9 28.27 63.62 81 729 3.000 2.080 10 31.42 78.54 100 1000 3.162 2.154 11 34.56 95.03 121 1331 3.316 2.223 12 37.70 113.10 144 1728 3.464 2.289 13 40.84 132.73 169 2197 3.605 2.351 14 43.98 153.94 196 2744 3.741 2.410 15 47.12 176.71 225 3375 3.872 2.466 16 50.26 201.06 256 4096 4.000 2.519 17 53.41 226.98 289 4913 4.123 2.571 18 56.55 254.47 324 5832 4.242 2.620 19 59.69 283.53 361 6859 4.358 2.668 20 62.83 314.16 400 8000 4.472 2.714 21 65.97 346.36 441 9261 4.582 2.758 22 69.11 380.13 484 10648 4.690 2.802 23 72.26 415.48 529 12167 4.795 2.843 24 75.40 452.39 576 13824 4.898 2.884 25 78.54 490.87 625 15625 5.000 2.924 26 81.68 530.93 676 17576 5.099 2.962 27 84.82 572.56 729 19683 5.196 3.000 28 87.96 615.75 784 21952 5.291 3.036 29 91.11 660.52 841 24389 5.385 3.072 30 94.25 706.86 900 27000 5.477 3.107 31 97.39 754.77 961 29791 5.567 3.141 32 100.53 804.25 1024 32768 5.656 3.174 33 103.67 855.30 1089 35937 5.744 3.207 341 342 AMERICAN GAS-ENGINEERING PRACTICE. DIMENSIONS OF CIRCLES, POWERS, AND ROOTS (Continued). Number or Diameter. Circum- ference. Circular Area. Square. Cube. Square Root. Cube Root. 34 106.81 907.92 1156 39304 5.830 3.239 35 109.96 962.11 1225 42875 5.916 3.271 36 113.10 1017.88 1296 46656 6.000 3.301 a? 116.24 1075.21 1369 50653 6.082 3.332 38 119.38 1134.11 1444 54872 6.164 3.361 39 122.52 1194.59 1521 59319 6.244 3.391 40 125.66 1256.64 1600 64000 6.326 3.419 42 131.95 1385.44 1764 74088 6.480 3.476 44 138.23 1520.53 1936 85184 6.633 3.530 46 144.51 1661.90 2116 97336 6.782 3.583 48 150.80 1809.56 2304 110592 6.928 3.634 50 157.08 ' 1963.50 2500 125000 7.071 3.684 52 163.36 2123.72 2704 140608 7.211 3.732 54 169.65 2290.22 2916 157464 7.348 3.779 56 175.93 2463.01 3136 175616 7.483 3.825 58 182.21 2642.08 3364 195112 7.615 3.870 60 188.50 2827.43 3600 216000 7.745 3.914 62 194.78 3019.07 3844 238328 7.874 3.957 64 201.06 3216.99 4096 262144 8.000 4.000 66 207.34 3421 . 19 4356 287496 8.124 4.041 68 213.63 3631.68 4624 314432 8.246 4.081 70 219.91 3848.45 4900 343000 8.366 4.121 72 226.19 4071.50 5184 373248 8.485 4.160 74 232.48 4300.84 5476 405224 8.602 4.198 76 238.76 4536.46 5776 438976 8.717 4.235 78 245.04 4778.36 6084 474552 8.831 4.272 80 251.33 5026.55 6400 512000 8.944 4.308 82 257.61 5281.02 6724 551368 9.055 4.344 84 263.89 5541.77 7056 592704 9.165 4.379 86 270.18 5808.80 7396 636056 9.273 4.414 88 276.46 6082.12 7744 681472 9.380 4.447 90 282.74 6361.73 8100 729000 9.486 4.481 92 289.03 6647.61 8464 778688 9.591 4.514 94 295.31 6939.78 8836 830584 9.695 4.546 96 301.59 7238.23 9216 884736 9.797 4.578 98 307.88 7542.96 9604 941192 9.899 4.610 100 314.16 7853.98 10000 1000000 10.000 4.641 102 320.41 8171.28 10404 1061208 10.099 4.672 104 326.73 8494.87 10816 1124864 10.198 4.702 106 333.01 8824.73 11236 1191016 10.295 4.732 108 339.29 9160.88 11664 1259712 10.392 4.762 11 345.57 9503.32 12100 1331000 10.488 4.791 112 351.86 9852.03 12544 1404928 10.583 4.820 114 358.14 10207.03 12996 1481544 10.677 4.848 116 364.42 10568.32 13456 1560896 10.770 4.876 118 370.71 10935.88 13924 1643032 10.862 4.904 120 376.99 11309.73 14400 1728000 10.954 4.932 122 383.27 11689.87 14884 1815848 11.045 4.959 MATHEMATICAL TABLES. 343 TABLE OF DIAMETERS, CIRCUMFERENCES, AND AREAS OF CIRCLES, AND SIDES OF EQUAL SQUARES. Diam. Circum- ference. Area. Sides of Equal Square. Diam. Circum- ference. Area. Sides of Equal Square. 11 34.557 95.033 9.7482 1 0.7854 0.0490 0.2215 Hi 35.343 99.402 9.9698 1.5708 .1963 .4431 Hi 36.128 103.869 10.191 2.3562 .4417 .6646 111 36.913 108.434 10.413 1 3.1416 .7854 .8862 12 37.699 113.097 10.634 1} 3.9270 1.2271 1 . 1077 121 38.484 117.859 10.856 1} 4.7124 1.7671 1.3293 12 39.270 122.718 11.077 If 5.4978 2.4052 1.5508 12| 40.055 127.676 11.299 2 6.2832 3.1416 1.7724 13 40.840 132.732 11.520 2* 7.0686 3.9760 J.9939 131 41.626 137.886 11.742 2* 7.8540 4.9087 2.2155 13J 42.411 143.139 11.963 2J 8.6394 5.9395 2.4370 13| 43.197 148.489 12.185 3" 9.4248 7.0686 2.6586 14 43.982 153.938 12.406 31 10.210 8.2957 2.8801 141 44.767 159.485 12.628 3* 10.995 9.6211 3.1017 14| 45.553 165.130 12.850 3| 11.781 11.044 3.3232 14| 46.338 170.873 13.071 4 12.566 12.566 3.5448 15 47.124 176.715 13.293 41 13.351 14.186 3.7663 151 47.909 182.654 13.514 4 i 14.137 15.904 3.9880 15 48.694 188.692 13.736 4| 14.922 17.720 4.2095 15| 49.480 194.828 13.957 5 15.708 19.635 4.4310 16 50.265 201.062 14.174 51 16.493 21.647 4.6525 161 51.051 207.394 14.400 5i 17.278 23.758 4.8741 16i 51.836 213.825 14.622 5| 18.064 25.967 5.0956 16| 52.621 220.353 14.843 6 18.849 28.274 5.3172 17 53.407 226.980 15.065 61 19.635 30.697 5.5388 171 54.192 233.705 15.286 6i 20.420 33.183 5.7603 17 54.978 240.528 15.508 6| 21.205 35.784 5.9819 17f 55.763 247.450 15.730 7 21.991 38.484 6.2034 18 56.548' 254.469 15.951 71 22.776 41.282 6.4350 181 57.334 261.587 16.173 7i 23.562 44.178 6.6465 18i 58.119 268.803 16.394 7| 24.347 47.173 6.8681 18| 58.905 276.117 16.616 8 25.132 50.265 7.0897 19 59.690 283.529 16.837 81 25.918 53.456 7.3112 191 60.475 291.039 17.060 8i 26.703 56.745 7.5328 19^ 61.261 298.648 17.280 81 27.489 60.132 7.7544 19| 62.046 305.355 17.502 9 28.274 63.617 7.9760 20 62.832 314.160 17.724 91 29.059 67.200 8.1974 201 63.617 322.063 17.945 9i 29.845 70.882 8.4190 20J 64.402 330.064 18.167 9| 30.630 74.662 8.6405 20| 65.188 338.163 18.388 10 31.416 78.540 8.8620 21 65.973 346.361 18.610 101 32.201 82.516 9.0836 211 66.759 354.657 18.831 10i 32.986 86.590 9.3051 2l| 67.544 363.051 19.053 10| 33.772 90.762 9.5267 2l| 68.329 371.543 19.274 344 AMERICAN GAS-ENGINEERING PRACTICE. TABLE OF DIAMETERS, CIRCUMFERENCES, AND AREAS OF CIRCLES, AND SIDES OF EQUAL SQUARES (Confined). Diam. Circum- ference. Area. Sides of Equal Square. Diam. Circum- ference. Area. Sides of Equal Square. 22 69.115 380.133 19.496 33 103.672 855.300 29.244 221 69.900 388.822 19.718 331 104.458 868.308 29.466 22* 70.686 397.608 19.939 33* 105.243 881.415 29.687 22! 71.471 406.493 20.161 33 106.029 894.619 29.909 23 72.256 415.476 20.382 34 106.814 907.922 30.131 231 73.042 424.557 20.604 341 107.599 921.323 30.352 23* 73.827 433.731 20.825 34* 108.385 934.822 30.574 23! 74.613 443.014 21.047 34! 109.170 948.419 30.795 24 75.398 452.390 21.268 35 109.956 962.115 31.017 241 76.183 461.864 21.490 35J 110.741 975.908 31.238 24* 76.969 471.436 21.712 35* 111.526 989.800 31.460 24 77.754 481 . 106 21.933 35! 112.312 1003.79 31.681 25 78.540 490.875 22.155 36 113.097 1017.87 31.903 251 79.325 500.741 22.376 36J 113.883 1032.06 32.124 25* 80.110 510.706 22.598 36* 114.668 1046.39 32.349 25| 80.896 520.769 22.819 36! 115.453 1060.73 32.567 26 81.681 530.930 23.041 37 116.239 1075.21 32.789 261 82.467 541 . 189 23.262 371 117.024 1089.79 33.011 26* 83.252 551.547 23.484 37* 117.810 1104.46 33.232 26! 84.037 562.002 23.708 37! 118.595 1119.24 33.454 27 84.823 672.556 23.927 38 119.380 1134.11 33.675 271 85.608 583.208 24.149 381 120.166 1149.08 33.897 27* 86.394 593.958 24.370 38* 120.951 1164.15 34.118 27| 87.179 604.807 24.592 38! 121.737 1179.32 34.340 28 87.964 615.763 24.813 39 122.522 1194.59 34.561 281 88.750 626.798 25.035 391 123.307 1209.95 34.783 28* 89.535 637.941 25.256 39* 124.093 1225.42 35.005 28| 90.321 649.182 25.478 39! 124.878 1240.98 35.226 29 91.106 660.521 25.699 40 125.664 1256.64 35.448 291 91.891 671.958 25.921 401 126.449 1272.39 35.669 29* 92.677 683.494 26.143 40* 127.234 1288.25 35.891 29! 93.462 695.128 26.364 40f 128.020 1304.20 36.112 30 94.248 706.860 26.586 41 128.805 1320.25 36.334 301 95.033 718.690 26.807 411 129.591 1336.40 36.555 30* 95.818 730.618 27.029 41* 130.376 1352.65 36.777 30! 96.604 742.644 27.250 41! 131.161 1369.00 36.999 31 97.389 754.769 27.472 42 131.947 1385.44 37.220 311 98.175 766.992 27.693 421 132.732 1401.98 37.442 31* 98.968 779.313 27.915 42* 133.518 1418.62 37.663 31| 99.745 791.732 28.136 42! 134.303 1435.36 37.885 32 100.531 804.249 28.358 43 135.088 1452.20 38.106 321 101.316 816.865 28.580 431 135.874 1469.13 38.328 32* 102.102 829.578 28.801 43* 136.659 1486.17 38.549 32| 102.887 842.390 29.023 43! 137.445 1503.30 38.771 MATHEMATICAL TABLES. 345 TABLE OF DIAMETERS, CIRCUMFERENCES, AND AREAS OF CIRCLES, AND SIDES OF EQUAL SQUARES (Continued). Diam. Circum- ference. Area. Sides of Equal Square. Diam. Circum- ference. Area. Sides of Equal Square. 44 138.230 1520.53 38.993 55 172.788 2375.83 48.741 441 139.015 1537.86 39.214 55i 173.573 2397.48 48.962 44 $ 139.801 1555.28 39.436 55 174.358 2419.22 49.184 44! 140.586 1572.81 39.657 55! 175.144 2441.07 49.405 45 141.372 1590.43 39.879 56 175.929 2463.01 49.627 451 142.157 1608.15 40.110 561 176.715 2485.05 49.848 45* 142.942 1625.97 40.322 56 J 177.500 2507.19 50.070 45| 143.728 1643.89 40.543 56| 178.285 2529.42 50.291 46 144.513 1661.90 40.765 57 179.071 2551.76 50.513 46i 145.299 1680.01 40.986 571 179.856 2574.19 50.735 46J 146.084 1698.23 41.208 57^ 180.642 2596.72 50.956 46| 146.869 1716.54 41.429 57| 181.427 2619.35 51.178 47 147.655 1734.94 41.651 58 182.212 2642.08 51.399 471 148.440 1753.45 41.873 581 182.998 2664.91 51.621 47i 149.226 1772.05 42.094 58 1^3.783 2687.83 51.842 47| 150.011 1790.76 42.316 58| 184.569 2710.85 52.064 48 150.796 1809.56 42.537 59 185.354 2733.97 52.285 481 151.582 1828.46 42.759 591 186.139 2757.19 52.507 48J 152.367 1847.45 42.980 59 *, 186.925 2780.51 52.725 48 1 153.153 1866.55 43.202 59! 187.710 2803.92 52.950 49 153.938 1885.74 43.423 60 188.496 2827.44 53.172 491 154.723 1905.03 43.645 601 189.281 2851.45 53.393 49i 155.509 1924.42 43.867 60| 190.066 2874.76 53.615 491 156.294 1943.91 44.088 60! 190.852 2898.56 53.836 50 157.080 1963.50 44.310 61 191.637 2922.47 54.048 501 157.865 1983.18 44.531 6U 192.423 2946.47 54.279 5Qi 158.650 2002.96 44.753 61J 193.208 2970.57 54.501 501 159.436 2022.84 44.974 6lf 193.993 2994.77 54.723 51 160.221 2042.82 45 . 196 62 194.779 3019.07 54.944 511 161.207 2062.90 45.417 62} 195.564 3043.47 55.166 51*. 161.792 2083.07 45.639 62*. 196.350 3067.96 55.387 51! 162.577 2103.34 45.861 62! 197.135 3092.56 55.609 52 163.363 2123.72 46.082 63 197.920 3117.25 55.830 521 164.148 2144.19 46.304 631 198.706 3142.04 56.052 524 164.934 2164.75 46.525 63* 199.491 3166.92 56.273 52f 165.719 2185.42 46.747 63| 200.277 3191.91 56.495 53 166.504 2206.18 46.968 64 201.062 3216.99 56.716 53| 167.290 2227.05 47.190 64} 201.847 3242.17 56.931 53J 168.075 2248.01 47.411 64* 202.633 3267.46 57.159 53| 168.861 2269.06 47.633 64| 203.218 3292.83 57.381 54 169.646 2290.22 47.853 65 204.204 3318.31 57.603 54i 170.431 2311.48 48.076 651 204.989 3343.88 .57.824 54 171.217 2332.83 48.298 65J 205.774 3369.56 58.046 54 1 172.002 2354.28 48.519 65! 206.560 3395.33 58.267 346 AMERICAN GAS-ENGINEERING PRACTICE. TABLE OF DIAMETERS, CIRCUMFERENCES, AND AREAS OF CIRCLES, AND SIDES OF EQUAL SQUARES (Continued). Diani. Circum- ference. Area. Sides of Equal Square. Diam. Circum- ference. Area. Sides of Equal Square. 66 207.345 3421.20 58.489 77 241.903 4656.63 68.237 661 208.131 3447.16 58.710 771 242.688 4686.92 68.459 66* 208.916 3473.23 58.932 77* 243.474 4717.30 68.680 66! 209.701 3499.39 59.154 77| 244.259 4747.79 68.902 67 210.487 3525.66 59.375 78 245.044 4778.37 69.123 671 211.272 3552.01 59.597 781 245.830 4809.05 69.345 67* 212.058 3578.47 59.818 78* 246.615 4839.83 69.566 67| 212.843 3605.03 60.040 78! 247.401 4870.70 69.788 68 213.628 3631.68 60.261 79 248.186 4901.68 70.009 681 214.414 3658.44 60.483 791 248.971 4832.75 70.231 68* 215.199 3685.29 60.704 79* 249.757 4963.92 70.453 68| 215.985 3712.24 60.926 79| 250.542 4995.19 70.674 69 216.770 3739.28 61.147 80 251.328 5026.56 70.869 69J 217.555 3766.43 61.369 801 252.113 5058.01 71.119 69* 218.341 3793.67 61.591 0* 252.898 5089.58 71.339 69| 219.126 3821.02 61.812 80! 253.684 5121.24 71.562 70 219.912 3848.46 62.934 81 254.469 5153.00 71.782 701 220.697 3875.99 62.255 811 255.255 5184.86 72.005 70* 221.482 3903.63 62.477 81* 256.040 5216.82 72.225 70| 222.268 3931.36 62.698 81! 256.825 5248.87 72.449 71 223.053 3959.20 62.920 82 257.611 5281.02 72.668 711 223.839 3987.13 63.141 821 258.396 5313.27 72.892 71* 224.624 4015.16 63.363 82* 259.182 5345.62 73.111 71| 225.409 4043.28 63.545 82| 259.967 5370.07 73.335 72 226.195 4071.51 63.806 83 260.753 5410.62 73.554 721 226.980 4099.83 64.028 831 261.538 5443.26 73.778 72* 227.766 4128.25 64.249 83* 262.3*23 5476.00 73.997 72| 228.551 4165.77 64.471 83| 263.109 5508.84 74.221 73 229.336 4185.39 64.692 84 263.894 5541.78 74.440 731 230.122 4212.11 64.914 841 264.679 5574.81 74.664 73* 230.907 4242.92 65.135 84* 265.465 5607.95 74.884 73! 231.693 4271.83 65.357 84! 266.250 5641.18 75.107 74 232.478 4300.85 65.578 85 267.036 5674.51 75.327 741 233.263 4329.95 65.800 851 267.821 5707.94 75.550 74* 234.049 4359.16 66.022 85* 268.606 5741.47 75.770 74! 234.834 4388.47 66.243 85! 269.392 5775.09 75.994 75 235.620 4417.87 66.465 86 270.177 5808.81 76.213 751 236.405 4447.37 66.686 861 270.963 5842.63 76.437 75* 237 . 190 4476.97 66.908 86* 271.748 5876.55 76.656 75| 237.976 4506.67 67 . 129 86f 272.533 5910.57 76.880 76 238.761 453.47 67.351 87 273.319 5944.69 77.099 761 239.547 4566.36 67.572 871 274.104 5978.90 77.323 76* 240.332 4596.35 67.794 87* 274.890 6013.21 77.542 76| 241.117 4626.44 68.016 87! 275.675 6047.62 77.766 MATHEMATICAL TABLES. 347 TABLE OF DIAMETERS, CIRCUMFERENCES, AND AREAS OF CIRCLES, AND SIDES OF EQUAL SQUARES (Continued). Diam. Circum- ference. Area. Sides of Equal Square. Mam. Circum- ference. Area. Sides of Equal Square. 88 276.460 6018.13 77.985 99 311.018 7697.70 87.736 88} 277.246 6116.74 78.209 99j 311.803 7736.62 87.958 88| 278.031 6151.44 78.428 99? 312.589 7775.65 88.179 278.817 6186.25 78.652 99| 313.374 7814.79 88.401 89 279.602 6221.15 78.871 100 314.160 7854.00 88.622 89} 280.387 6256.15 79.095 100] 314.945 7893.31 88.844 89* 281.173 6291.25 79.315 100* 315.730 7932.73 89.065 89| 281.958 6326.44 79.538 lOOf 316.516 7972.21 89.287 90 282.744 6361.74 79.758 101 317.301 8011.86 89.508 90} 283.529 6397 . 13 79.982 101} 318.087 8051.57 89.730 90i 284.314 6432.62 80.201 101* 318.872 8091.38 89.952 90f 285.100 6468.21 80.424 101| 319.657 8131.29 90.173 91 285.885 6503.89 80.644 102 320.443 8171.30 90.395 91} 286.671 6539.68 80.868 102} 321.228 8211.40 90.616 91 287.456 6573.56 81.087 102 322.014 8251.60 90.838 9l| 288.241 6611.54 81.311 102! 322.799 8291.86 91.059 92 289.027 6647.62 81.530 103 323.584 8332.30 91.281 92} 289.812 6683.80 81.754 103} 324.370 8372.80 91.502 92 290.598 6720.07 81.973 103* 325.155 8413.40 91.724 92J 291.383 6756.45 82.197 103| 325.941 8454.09 91.946 93 292.168 6792.92 82.416 104 326.726 8494.88 92.167 93} 292.954 6829.49 82.640 104} 327.511 8535.77 92.389 93 293.739 6866.16 82.859 104] 328.297 8576.76 92.610 93| 294.535 6902.92 83.083 1041 329.082 8617.85 92.832 94 295.310 6939.79 83.302 105 329.868 8569.03 93.053 94} 296.095 6976.75 83.526 105} 330.653 8700.31 93.275 94 296.881 7013.81 83.746 105i 331.438 8741.69 93.496 94| 297.666 7050.97 83.970 105! 332.224 8783.17 93.718 95 298.452 7088.23 84.189 106 333.009 8824.75 93.940 95} 299.237 7125.58 84.413 106} 333.794 8866.42 94.161 95i 300.022 7163.04 84.632 1C6J 334.580 8908.20 94.383 95| 300.808 7200.59 84.856 106s 335.365 8950.07 94.604 96 301.593 7238.24 85.077 107 306.151 8992.04 94.826 96} 302.379 7275.99 85.299 107} 306.935 9034.11 95.047 96 303.164 7313.84 85.520 107^ 337.722 9076.27 95.269 96f 303.949 7351.78 85.742 107J 338.506 9118.54 95.491 97 304.735 7389.82 85.964 108 339.292 9160.90 95.712 97} 305.520 7427.96 86.185 108} 340.077 9203.36 95.534 97i 306.306 7466.20 86.407 108. 340.863 9245.92 96.155 97| 307.091 7504.54 86.628 108? 341.648 9288.58 96.377 98 307.876 7542.98 86.850 109 342.434 9331.33 96.598 98} 308.662 7581.51 87.071 109} 343.219 9374.18 96.820 98i 309.447 7620.14 87.293 109i 344.005 9417.14 97.041 98| 310.233 7658.87 87.514 109: 344.789 9460.19 97.263 348 AMERICAN GAS-ENGINEERING PRACTICE. TABLE OF DIAMETERS, CIRCUMFERENCES, AND AREAS OF CIRCLES, AND SIDES OF EQUAL SQUARES (Confined). Diam. Circum- ference. Area. Sides of Equal Square. Diam. Circum- ference. Area. Sides of Equal Square. 110 345.575 9503.34 97.485 121 380.132 11499.04 107.334 1101 346.360 9546.59 97.707 1211 380.918 11546.61 107.455 110$ 347.146 9589.93 97.928 121* 381.703 11594.27 107.677 110| 347.931 9633.37 98.150 121! 382.489 11642.0c 107.898 Ill 348.716 9776.91 98.371 122 383.274 11689. 8S 108.120 11U 349.502 9720.55 98.593 122-1 384.059 11747.85 108.341 111* 350.287 9764.29 98.814 122$ 384.845 11785.91 108.563 111| 351.073 9808.12 99.036 122f 385.630 11834.0t 108.784 112 351.858 9852.06 99.258 123 386.416 11882.31 109.006 1121 352.643 9896.09 99.479 123-1 387.201 11930.67 109.228 112* 353.429 9940.21 99.701 123$ 387.986 11979.11 109.449 112! 354.214 9984.45 99.922 123! 388.772 12027.6e 109.671 113 355.000 10028.77 100.144 124 389.557 12076.31 109.892 1131 355.785 10073.20 100.365 124} 390.343 12 125. Of 110.114 113* 356.570 10117.72 100.587 124* 391.128 12173. 9C 110.335 113| 357.356 10162.34 100.808 124! 391.913 12222. 8< 110.557 114 358.141 10207.06 101.030 125 392.699 12271. 8 110.778 114$ 358.927 10251.88 101.252 1251 393.484 12321.01 111.000 114* 359.712 10296.79 101.473 125$ 394.270 12370.25 111.222 114f 360.497 10341.80 101.695 125f 395.055 12419.5* 111.443 115 361.283 10386.92 101.916 126 395.840 12469.01 111.665 1151 362.068 10432.12 102.138 1261 396.626 12518.54 111.886 115* 362.854 10477.43 102.359 126* 397.411 12568.17 112.108 115| 363.639 10522. 8< 102.581 126! 398.197 12617. 8 112.329 116 364.424 10568. 3< 102.802 127 398.982 12667.72 112.551 1161 365.210 10613.94 103.024 1271 399.767 12717.64 112.772 116* 365.995 10659.65 103.246 127$ 400.553 12767.66 112.994 116| 366.780 10705.44 103.467 127! 401.338 12817. 7 113.216 117 367.566 10751.34 103.689 128 402.124 12868. Of 113.437 1171 368.351 10797.34 103.910 1281 402.909 12918.3] 113.659 117* 389.137 10843.43 104.132 128$ 403.694 12968.71 113.880 117| 369.922 10889.62 104.353 128! 404.480 13019.22 114.102 118 370.708 10935.91 104.575 129 405.265 13069.84 114.323 1181 371.493 10982.30 104.796 1291 406.051 13120.55 114.545 118* 371.278 11028.78 105.018 129* 406.836 13171.35 114.767 118| 371.064 11075.37 105.240 129! 407.621 13222.26 114.988 119 373.849 11122.05 105.461 130 408.407 13273.26 115.210 1191 374.635 11168.83 105.683 1301 409.192 13324.36 115.431 119* 375.420 11215.71 105.904 130* 409.977 13375.56 115.653 119! 376.205 11262.69 106.126 130! 410.763 13426.85 115.874 120 376.991 11309.76 106.347 131 411.548 13478.25 116.096 1201 377.776 11356.93 106.569 1311 412.334 13529.7^ 116.317 120* 378.562 11404.20 106 . 790 131* 413.119 13581.33 116.539 120| 379.347 11451.57 107.012 131! 413.904 13633.01 116.761 MATHEMATICAL TABLES. 349 TABLE OF DIAMETERS, CIRCUMFERENCES, AND AREAS OF CIRCLES, AND SIDES OF EQUAL SQUARES (Continued). Diam. Circum- ference. Area. Sides of Equal Square. )iam. Circum- ference. Area. Sides of Equal Square. 132 414.690 13684.81 116.982 143 449.247 16060.64 126.731 1321 415.475 13736.70 117.204 1431 450.033 16116.85 126.952 132* 416.260 13788.68 117.425 1431 450.818 16173.15 127.174 132| 417.046 13840.76 117.647 143| 451.604 16229.55 127.395 133 417.831 13892.94 117.868 144 452.389 16286.05 127.617 1331 418.617 13945.22 118.090 1441 453 . 174 16334.66 127.838 133* 419.402 13997.60 118.311 144f 453.960 16399.35 128.060 133| 420.188 14050.07 118.533 144| 454.745 16456.14 128.281 134 420.973 14102.64 118.755 145 455.531 16513.04 128.503 1341 421.758 14155.31 118.976 1451 456.316 16570.03 128.725 1341 422.544 14208.08 119.198 145* 457.101 16627.11 128.946 134f 423.329 14260.95 119.419 145| 457.887 16684.30 129.168 135 424.115 14313.92 119.641 146 458.672 16741.59 129.389 1351 424.900 14366.98 119.862 1461 459.458 16798.97 129.611 1351 425.685 14420.14 120.084 146} 460.243 16856.45 129.832 135| 426.470 14473.40 120.305 146| 461.028 16914.03 130.054 136 427.256 14526.76 120.527 147 461.814 16971.71 130.276 1361 428.042 14580.21 120.749 1471 462.599 17029.48 130.497 1361 428.827 14633.77 120.970 1471 463.385 17087.36 130.719 133| 429.612 14687.42 121.192 147| 464.170 17145.33 130.940 137 430.398 14741.12 121.413 148 464.955 17203.40 131.162 1371 431.183 14795.02 121.635 1481 465.741 17261.57 131.383 1371 431.969 14848.97 121.856 1481 466.526 17319.84 131.605 137| 432.554 14903.01 122.078 148| 467.312 17378.20 131.826 138 433.539 14957.16 122.299 149 468.097 17436.67 132.048 1381 434.325 15011.40 122.521 1491 468.882 17495.22 132.270 138J 435.110 15065.74 122.743 1491 469.668 17553.89 132.491 13SJ 435.896 15120.18 122.964 149| 470.453 17612.64 132.713 139 436.681 15174.71 123.186 150 471.239 17671.50 132.934 1391 437.466 15229.35 123.407 1501 472.024 17730.45 133.156 1391 438.252 15284.08 123.629 1501 472.809 17789.51 133.377 1391 439.037 15338.91 123.850 150| 473.595 17848.66 133.599 140 439.823 15393.84 124.072 151 474.380 17907.91 133.820 140J 440.608 15448.87 124.293 1511 475.165 17967.2, r 134.042 140* 441.393 15503.99 124.515 1511 475.951 18026.7C 134.264 140f 442.179 15559.22 124.737 151| 476.736 18086.24 134.485 141 442.964 15614.54 124.958 152 477.522 18145.88 134.707 1411 443.750 15669.96 125.180 1521 478.307 18205.62 134.928 14ll 444.535 15725.48 125.401 1521 479.092 18265.46 135.150 141| 445.320 15781.09 125.623 152| 479.878 18325. 3e 135.371 142 446.106 15836.81 125.844 153 480.663 18385.43 135.593 1421 446.891 15892.62 126.066 1531 481.449 18445.56 135.814 142* 447.677 15948.53 126.287 1531 482.234 18505.79 T36.036 142| 448.462 16004.54 126.509 153| 483.019 18566.12 136.258 350 AMERICAN GAS-ENGINEERING PRACTICE. TABLE OF DIAMETERS, CIRCUMFERENCES, AND AREAS OF CIRCLES, AND SIDES OF EQUAL SQUARES (Continued). Diam. Circum- ference. Area. Sides of Equal Square. Diam. Circum- ference. Area. Sides of Equal Square. 154 483.805 18626.55 136.479 165 518.362 21382.52 146.228 154* 484.590 18687.07 136.701 165} 519.148 21447.36 146.449 154* 485.376 18747.69 136.922 65* 519.933 21512.30 146.671 154f 486.161 18808.42 137.144 165| 520.719 21577.34 146.892 155 486.946 18869.24 137.365 166 521.504 21642.48 147.114 1551 487.932 18930.15 137.587 166} 522.290 21707.72 147.335 155* 488.517 18991 . 17 137.808 166* 523.075 21773.06 147.557 155| 489.303 19052.28 138.030 66| 523.860 21838.49 147.779 156 490.088 19113.49 138.252 167 524.646 21904.02 148.000 1561 490.873 19174.80 138.473 167} 525.431 21969.65 148.222 156* 491.659 19236.21 138.695 167* 526.216 22035.08 148.443 156f 492.444 19297.72 138.916 167| 527.002 22101.21 148.665 157 493.230 19359.32 139.138 168 527.787 22167.13 148.886 1571 494.015 19421.03 139.359 168} 528.573 22233.15 149.108 157* 494.800 19482.83 139.581 168* 529.358 22299 . 27 149.329 157J 495.586 19544.73 139.802 168| 530.143 22365.49 149.551 158 496.371 19605.73 140.024 169 530.929 22431.81 149.773 1581 497.157 19668.82 140.246 169} 531.714 22498.22 149.994 158* 497.942 19731.02 140.467 169* 532.500 22564.74 150.216 158| 498.727 19793.31 140.689 169| 533.285 22631.35 150.437 159 499.513 19855.70 140.910 170 534.070 22698.06 150.659 1591 500.298 19918. IT 141.132 170} 534.856 22764.87 150.880 159* 501.084 19980.77 141.353 170* 535.641 22831.77 151.102 159| 501.869 20043. 4C 141.575 170| 536.426 22898.79 151.323 160 502.654 20106.24 141.796 171 537.212 22965.88 151.545 1601 503.440 20169.12 142.018 171} 537.997 23033.08 151.767 160* 504.225 20232.10 142.240 171* 538.783 23100.38 151.988 160| 505.011 20295. If 142.461 17l| 539.568 23167.78 152.210 161 505.796 20358.35 142.683 172 540.353 23235.27 152.431 1611 506.581 20421.6? 142.904 172} 541.139 23302.87 152.653 161* 507.367 20485.00 143 . 126 172* 541.924 23370.56 152.874 161| 508.152 20548.47 143.347 172| 542.710 23438.35 153.096 162 508.938 20612.0;' 143.569 173 543.495 23506.24 153.317 162} 509.723 20675.70 143.790 173} 544.280 23574.22 153 . 539 162* 510.508 20739.47 144.012 173* 545.066 23642.31 153.761 162| 511.294 20803.33 144.234 173J 545.851 23710.49 153.982 163 512.079 20867. 2P 144.455 174 546.637 23778.77 154.204 1631 512.865 20931.35 144.677 174} 547.422 23847.15 154.425 163* 513.650 20995.51 144.898 174* 548.207 23915.63 154.1647 163| 514.435 21059.76 145.120 174| 548.993 23984.20 154.868 164 515.221 21124.12 145.341 175 549.778 24052.88 155.090 164} 516.006 21188.57 145.563 175} 550.564 24121.65 155.311 164* 516.792 21253.12 145.784 175* 551.349 24190.52 155.533 164f 517.577 21317.77 146.006 175| 552.134 24259.48 155.755 MATHEMATICAL TABLES. 351 TABLE OF DIAMETERS, CIRCUMFERENCES, AND AREAS OF CIRCLES, AND SIDES OF EQUAL SQUARES (Continued'). Diam. Circum- ference. Area. Sides of Equal Diam. Circum- ference. Area. Sides of Equal Square. Square. 176 552.920 24328.55 155.976 188 590.619 27759 . 18 166.611 1761 553.705 24397.71 156.198 1881 591.404 27833 . 05 166.832 1761 554.491 24466.98 156.419 1881 592.190 27907.03 167.054 176| 555.276 24536.34 156.641 188| 592.975 27981 . 10 167.276 177 556.061 24605.80 156.862 189 593.761 28055.27 167.497 1771 556.847 24675.35 157.084 1891 594.546 28129.54 167.719 177J 557.632 24745.01 157.305 1891 595.331 28203.91 167.940 177| 558.418 24814.76 157.527 189| 596.117 28278.38 168.162 178 559.203 24884.61 157.749 190 596.902 28352.94 168.383 1781 559.988 24954.56 157.970 1901 597.687 28427.60 168.605 1781 560.774 25024.61 158.192 190| 598.473 28502.36 168.826 178| 561.559 25094.76 158.413 190J 599.258 28577.22 169.048 179 562.345 25165.00 158.635 191 600.044 28652.18 169.270 1791 563 . 130 25235.34 158.856 1911 600.829 28727.23 169.491 1791 563.915 25305.78 159.078 1911 601.614 28802.39 169.713 179| 564.701 25376.32 159.299 19lf 602.400 28877.64 169.934 180 565.486 25446.96 159.521 192 603 . 185 28952.99 170.156 1801 566.272 25517.70 159.743 1921 603.971 29028.43 170.377 1801 567.057 25588.53 159.964 192* 604.756 29103.98 170.599 180| 567.842 25659.46 160.186 192| 605.541 29179.62 170.820 181 568.628 25730.49 160.407 193 606.327 29255.37 171.042 1811 569.413 25801.62 160.629 1931 607.112 29331.21 171.264 181* 570.199 25872.84 160.850 1931 607.898 29407 . 14 171.485 181| 570.984 25944.17 161.072 193| 608.683 29483.18 171.707 182 571.769 26015.59 161.293 194 609.468 29559.32 171.928 1821 572.555 26087.11 161.515 1941 610.254 29635 . 55 172.150 182^ 573.340 26158.73 161.737 1941 611.039 29711.88 172.371 182| 574.126 26230.45 161.958 194| 611.825 29788.31 172.593 183 574.911 26302.26 162.180 195 612.610 29864.84 172.814 1831 575.696 26374.17 162.401 1951 613.395 29941.46 173.036 1831 576.482 26446 . 19 162.623 1951 614.181 30018.19 173.258 183| 577.267 26519.29 162.844 195| 614.966 30095.01 173.479 184 578.053 26590.50 163.066 196 615.752 30171.93 173.701 1841 578.838 26662.81 163.287 1961 616.537 30248.95 173.922 1841 579.623 26735.21 163.509 196* 617.322 30326.06 174.144 184f 580.409 26807.71 163.732 196f 618.108 30403.28 174.365 185 581.194 26880.32 163.952 197 618.893 30480.59 174.587 1851 581.980 26953.01 164.174 1971 619.679 30588.00 174.808 1851 582.765 27025.81 164.395 1971 620.464 30635.51 175.030 185| 583.550 27098.71 164.617 197| 621.249 30713.12 175.252 186 584.336 27171.70 164.838 198 622.035 30790.82 175.473 1861 585.121 27244.79 165.060 1981 622.820 30868.63 175.695 1861 585.907 27317.98 165.282 198* 623.606 30946.53 175.916 186| 586 . 692 27391.27 165.503 198| 624.391 31024.53 176.138 187 587.477 27464.65 165.725 199 625.176 31102.63 176.359 1871 588.263 27538.14 165.946 1991 625.962 31180.82 176.581 1871 589.048 27611.72 166.168 1991 626.747 31259.12 176.802 187| 589.834 27685.40 166.389 199| 627.533 31337.49 177.024 200 628.318 31415.98 177.246 352 AMERICAN GAS-ENGINEERING PRACTICE. DECIMAL EQUIVALENT OF AN INCH. 8ths. A = .5625 H = .53125 A = . 140625 tt =.578125 i =.125 ft = .6875 ft = .59375 tt = . 171875 if = .609375 i = .250 tt =.8125 ft = .65625 if = .203125 tt = .640625 t = .375 if = .9375 & = .71875 if = .234375 if = .671875 * = .500 ft = .78125 = .265625 If = .703125 * = .625 32ds. ft = .84375 if = .296875 tt = .734375 f = .750 A = .03125 * = .90625 tt = .328125 tt = . 765625 J = .875 A = .09375 ft = .96875 If = .359375 tt = .796875 A = 15625 if = .390625 tt =.828125 leths. A =.21875 64ths. tt = .421875 if =.859375 A = . 0625 A = .28125 A = .015625 if = .453125 tt =.890625 A = . 1875 ft = . 34375 A = -046875 if = .484375 if = .921875 A = .3125 ft = . 40625 A = .078125 H = .515627 it = .953125 A = .4375 H = .46875 A - .109375 if = .546875 H = .984375 LOGARITHMS OF CONVENIENT CONSTANTS. Compiled by J. J. Clark. Number. Logarithm. Reciprocal. Logarithm. TT 3 1416 .4971509 318309 1 5028491 -= 7854 1 . 8950909 1 273237 1049091 ^ 7r 2 = 9.86965 .9943018 . 10132 1 . 0056982 VTT= 1 772457 2485755 .5641888 1 7514245 .11.= 564189. . 1 7514245 1 . 772456 2485755 N* 32 16 1 5073160 0310945 2 4926840 $016 08 1 2062860 06218906 2 7937140 20 6432 1 8083460 01554727 2 1916540 V^2g= 8.019974 1 cu. in. water weighs .03617 Ibs. . . Water-column l"Xl"Xl' weighs 43403 Ibs .9041730 2.5583485 1 6375197 . 1246887 27.64723 2 303988 1.0958270 1.4416515 3624803 Water-column 1" d.Xl' weighs 34088 Ibs 1 5326015 2 . 933584 4673985 1 Ib . water = column 1" X V X 2.304' 1 Ib. water = column 1" d. X 2.9336' 1 cu. ft. air at 32 F. and 30" Hg weighs 08073 Ibs .3624825 .4674009 2 9070350 .4340278 .340878 12 387 1.6375175 1.5325991 1 0929650 1 gal H O weighs 8 355 Ibs 9219465 11969 1 0780535 1 cu. ft. H 2 O contains 7.48 gal 147 .8739016 1 1673173 . 13369 06802721 I . 1260984 2 8326827 1728 3 2375437 .0005787037 4 . 7624563 778 2 . 8909796 .001285347 3.1090204 144 . 2.1583625 . 00694445 3.8416375 12 1.0791812 .0833333 2.9208188 33000 4 5185139 0000303 5 4814861 MATHEMATICAL TABLES. 353 LENGTHS OF CHORDS FOR SPACING CIRCLE WHOSE DIAMETER IS 1. For Circles of other Diameters Multiply Length given in Table by Diameter of Circle. No. of Spaces Length of Chord. No. of Spaces. Length of Chord. No. of Spaces. Length of Chord. No. of Spaces. Length of Chord. 26 .1205 51 .0616 76 .0413 27 .1161 52 .0604 77 .0408 3 .8660 28 .1120 53 .0592 78 .0403 4 .7071 29 .1081 54 .0581 79 .0398 5 .5878 30 .1045 55 .0571 80 .0393 6 .5000 31 .1012 56 .0561 81 .0388 7 .4339 32 .0980 57 .0551 82 .0383 8 .3827 33 .0951 58 .0541 83 .0378 9 .3420 34 .0923 59 .0532 84 .0374 10 .3090 35 .0896 L 60 .0523 85 .0370 11 .2817 36 .0872 61 .0515 86 .0365 12 .2588 37 .0848 62 .0507 87 .0361 13 .2393 38 .0826 63 .0499 88 .0357 14 .2225 39 .0805 64 .0491 89 .0353 15 .2079 40 .0785 65 .0483 90 .0349 16 .1951 41 .0765 66 .0476 91 .0345 17 .1838 42 .0747 67 .0469 92 .0341 18 .1736 43 .0730 68 .0462 93 .0338 19 .1646 44 .0713 69 .0455 94 .0334 20 .1564 45 .0698 70 .0449 95 .0331 21 .1490 46 .0682 71 .0442 96 .0327 22 .1423 47 .0668 72 .0436 97 .0324 23 .1362 48 .0654 73 .0430 98 .0321 24 .1305 49 .0641 74 .0424 99 .0317 25 .1253 50 .0628 75 .0419 100 .0314 354 AMERICAN GAS-ENGINEERING PRACTICE. LOGARITHM OF NUMBERS FROM TO 1200. No. 1 2 3 4 5 6 7 8 9 Prop. 00000 30103 47712 60206 69897 77815 84510 90309 95424 10 00000 00432 00860 01284 01793 02119 02531 02938 03342 03743 415 11 04139 04532 04922 0530S 05690 06070 06746 06819 07188 07555 379 12 07918 08279 08636 08991 09342 09691 10037 10380 10721 11059 344 13 11394 11727 12057 12385 12710 13033 13354 13672 13988 14301 323 14 14613 14922 15229 15534 15836 16137 16435 16732 17026 17319 298 15 17609 17898 18184 18468 18752 19033 19312 19590 19866 20140 281 16 20412 20683 20952 21219 21484 21748 22011 22272 22531 22789 264 17 23045 23300 23553 23805 24055 24304 24551 24797 25042 25285 249 18 25527 25768 26007 26245 26482 26717 26951 27184 27416 27646 234 19 27875 28103 28330 28556 28780 29003 29226 29447 29667 29885 222 20 30103 30320 30535 30750 30963 31175 31387 31597 31806 32015 212 21 32222 32428 32634 32838 33041 33244 33415 33646 33846 34044 202 22 34242 34439 34635 34830 35025 35218 35411 35603 35793 35984 193 23 36173 36361 36549 36736 37922 37107 37291 37475 37658 37840 185 24 38021 38202 38382 38561 38739 38917 39094 39270 39445 39620 177 25 39794 39967 40140 40312 40483 40654 40824 40993 41162 41330 170 26 41497 41664 41830 41996 42160 42325 42488 42651 42813 42975 164 27 43136 43297 43457 43616 43775 43933 44091 44248 44404 44560 158 28 44716 44871 45025 45179 45332 45484 45637 45788 45939 46090 153 29 46240 46389 46538 46687 46835 46982 47129 47276 47422 47567 148 30 47712 47857 48001 48144 48287 48430 48572 48714 48855 48966 143 31 49136 49276 49415 49554 49693 49831 49969 50106 50243 50379 138 32 50515 50651 50786 50920 51055 51189 51322 51455 51587 51720 134 33 51851 51983 52114 52244 52375 52504 52634 52763 52892 53020 130 34 53148 53275 53403 53529 53656 53782 53908 54033 54158 54283 126 35 54407 54531 54654 54777 54900 55023 55145 55267 55388 55509 122 36 55630 55751 55871 55991 56110 56229 56348 56467 56585 56703 119 37 56820 56937 57054 57171 57287 57403 57519 57634 57749 57864 116 38 57978 58093 58206 58320 58433 58546 58659 58771 58883 58995 113 39 59106 59218 59329 59439 59550 59660 59770 59879 59988 60097 110 40 60206 60314 60423 60531 60638 60746 60853 60959 61066 61172 107 41 61278 61384 61490 61595 61700 61805 61909 62014 62118 62221 104 42 62325 62428 62531 62634 62737 62839 62941 63043 63144 63246 102 43 63347 63448 63548 63649 63749 63849 63949 64048 64147 64246 99 44 64345 64444 64542 64640 64738 64836 64933 65031 65128 65225 98 45 65321 65418 65514 65610 65706 65801 65896 65992 66087 66181 96 46 66276 66370 66464 66558 66652 66745 66839 66932 67025 67117 95 47 67210 67302 67394 67486 67578 67669 67761 67852 67943 68034 92 48 68124 8215 68305 68395 68485 68574 68664 68753 68842 68931 90 49 69020 69108 69197 69285 69373 69461 69548 69636 69723 69810 88 50 69897 69984 70070 70157 70243 70329 70415 70501 70586 70672 86 51 70757 70842 70927 71012 7109f> 71181 71265 71349 71433 71517 84 52 71600 71684 71767 71850 71933 72016 72099 72181 72263 72346 82 53 72428 72509 72591 72673 72754 72835 72916 72997 73078 73159 81 Indices of Logarithms: Log. 4030 = 3.60530 " 403 = 2.60530 Log. 40.3 = 1.60530 " 4.03= .60530 " .403= .60530 Log. .0403 = " .00403= t. 60530 r. 60530 Find Log. of 5065 Log. of 5060 Prop. 86 X Diff. 5 = 3.70415 430 Log. required = 3 . 704580 Find number of Log. . . 3. 771442 Log. of 5900= 3.770850 iff. 592 -H Prop. 73 = 8. Diff. = 592 No. required 5908 MATHEMATICAL TABLES. LOGARITHM OF NUMBERS FROM TO 1200 Con tinned. 355 No. 1 2 3 4 5 6 7 8 9 Prop. 54 73239 73320 73400 73480 73560 73670 73719 73799 73878 73957 80 55 74036 74115 74194 74273 74351 74429 74507 74586 74663 74741 78 56 74819 74896 74974 75051 75128 75205 75282 75358 75435 75511 77 57 75587 75664 75740 75815 75891 75967 76042 76118 76193 76268 75 58 76343 76418 76492 76567 76641 76716 76790 76864 76938 77012 74 59 77085 77159 77232 77305 77379 77452 77525 77597 77670 77743 73 60 77815 77887 77960 78032 78104 78176 78247 78319 78390 78462 72 61 78533 78604 78675 78746 78817 78888 78958 79029 79099 79169 71 62 79239 79309 79379 79449 79518 79588 79657 79727 79796 79865 70 63 79934 80003 80072 80140 80209 80277 80346 80414 80482 80550 69 64 80618 80686 80754 80821 80889 80956 81023 81090 81158 81224 68 65 81291 81358 81425 81491 81558 81624 81690 81757 81823 81889 67 66 81954 82020 82086 82151 82217 82282 82347 82413 82478 82543 66 67 82607 82672 82737 82802 82866 82930 82995 83059 83123 83187 64 68 83251 83315 83378 83442 83506 83569 83632 83693 83759 83822 63 69 83885 83948 84011 84073 84136 84198 84261 84223 84386 84448 63 70 84510 84572 84634 84696 84757 84819 84880 84942 85003 85065 62 71 85126 85187 85248 85309 85370 85431 85491 85552 85612 85673 61 72 85733 85794 85854 85914 85974 86034 86094 86153 86213 86273 60 73 86332 86392 86451 86510 86570 86629 86688 86747 86806 86864 59 74 86923 86982 87040 87099 87157 87216 87274 87332 87390 87448 58 75 87506 87564 87622 87680 87737 87795 87852 87910 87967 88024 57 76 88081 88138 88196 88252 88309 88366 88423 88480 88536 88593 57 77 88649 88705 88762 88818 88874 88930 88986 89042 89098 89154 56 78 89209 89265 89321 89376 89432 89487 89542 89597 89653 89708 55 79 89763 89818 89873 89927 89982 90037 90091 90146 90200 90255 54 80 90309 90363 90417 90472 90526 90580 90634 90687 90741 90795 54 81 90849 90902 90956 91009 91062 91116 91169 91222 91275 91328 53 82 91381 91434 91487 91540 91593 91645 91698 91751 91803 91855 53 83 91908 91960 92012 92065 92117 92169 92221 92273 92324 92376 52 84 92428 92480 92531 92583 92634 92686 92737 92788 92840 92891 51 85 92942 92993 93044 93095 93146 93197 93247 93298 93349 93399 51 86 93450 93500 93551 93601 93651 93702 93752 93802 93852 93902 50 87 93952 94002 94052 94101 94151 94201 94250 94300 94349 94399 49 88 94448 94498 94547 94596 94645 94694 94743 94792 94841 94890 49 89 94939 9*988 95036 95085 95134 95182 95231 95279 95328 95376 48 90 95424 95472 95521 95569 95617 95665 95713 95761 95809 95856 48 91 95904 95952 95999 96047 96095 96142 96190 96237 96284 96332 48 92 96379 96426 96473 96520 96567 96614 96661 96708 96755 96802 47 93 96848 96895 96942 96988 97035 97081 97128 97174 97220 97267 47 94 97313 97359 97405 97451 97497 97543 97589 97635 97681 97727 46 95 97772 97818 97864 97909 97955 98000 98046 98091 98137 98182 46 96 98227 98272 98318 98363 98408 98453 98498 98543 98588 98632 45 97 98677 98722 98767 98811 98856 98900 98945 98989 99034 99078 45 98 99123 99167 99211 99255 99300 99344 99388 99432 99476 99520 44 99 99564 99607 99651 99695 99739 99782 99826 99870 99913 99957 44 100 00000 00043 00087 00130 00173 00217 90260 00303 00346 00389 43 101 00432 00475 00518 00561 00604 00647 00689 00732 00775 00817 43 102 00860 00903 00945 00988 01030 01072 01115 01175 01199 01242 42 103 01284 01326 01368 01410 01452 01494 01536 01578 01620 01662 42 To multiply by logarithms add the logarithms together and find the corresponding number. To divide by logarithms subtract one from the other. To extract the root divide the logarithm by the index of the root and find the num- ber corresponding to it. To raise a number to any power multiply the logarithm by the index of the power and find the corresponding number. 356 AMERICAN GAS-ENGINEERING PRACTICE. LOGARITHM OF NUMBERS FROM TO 1200 Continued. No. 1 2 3 4 5 6 7 8 9 Prop. 104 01703 01745 01787 01828 01870 01912 01953 01995 02036 02078 42 105 02119 02160 02202 02243 02284 02325 02366 02407 02449 02490 41 106 02531 02572 02612 02653 02694 02735 02776 02816 02857 02898 41 107 02938 02979 03019 03060 03100 03141 03181 03222 03262 03302 41 108 03342 03383 03423 03463 03503 03543 03583 03623 03663 03703 40 109 03743 03782 03822 03S62 03902 0394] 0398! 04021 04060 04100 40 110 04139 04179 04218 04258 04297 04336 04376 04415 04454 04493 39 111 04532 01571 04610 04650 04689 04727 04766 Oi805 04844 04883 39 112 04922 04961 04999 05038 05077 05115 05154 05192 05231 05269 39 113 05308 05346 05385 05423 05461 05500 05538 05576 05614 05652 38 114 05690 05729 05767 05805 05843 05881 05918 05956 05994 06032 38 115 00076 0^108 06145 06183 06221 06258 06296 06333 06371 06408 38 116 06446 064S3 06521 06558 06595 06633 06670 06707 06744 06781 37 117 06819 068 6 06893 06930 06967 07004 07041 07078 07115 07151 37 118 07188 07225 07262 07298 07335 07372 07408 07445 07482 07518 37 119 07555 07591 07628 07644 07700 07737 07773 07809 07846 07882 36 INVOLUTION AND EVOLUTION or FRACTIONS BY LOGARITHMS. In a logarithm the integer is called the characteristic, and the decimal portion the man- tissa. INVOLUTION. The number carried from the mantissa to the characteristic being posi- tive, must be deducted from the negative characteristic . Example. Find the 5th power of .05. or the value of .05 s . Log. .05 = 2 .J>9897 then 2X5 =10 + and .69897X5 = 3.49485 Then log. .05 s = 7. 49485 and .05 5 = .0000003125 EVOLUTION. If the negative characteristic be not divisible without a remainder by the index of the required root, the number of units sufficient to make it so divisible must be added to it, and the same number of units must also be added to the mantissa before division. Example. Find the value of ^.0000003125. Log. .00000031 25 = 7. 49485_ then 7 + 3=-- 10, and 10-5-2 and 3. 49485- 5= . 3.03654 1.83442 Therefore log. .0000003125 = 2. 69897 = log. of .05. PROPORTION BY LOGARITHMS. Add together the logarithms of the 2d and 3d terms, and from jtheir sum subtract the logarithm of the first term, then the number corresponding to the logarithm of fhe remainder gives the required answer. Example. 68.30 : 13.70 : : 79.40 : ? Log. 13.70 = 1.13672 Log. 79. 40-1. Sum Log. 68.30 = Diff. 1.20212 = log. of 15.93. The common logarithm of any number is the power to which, if 10 be raised, the said number is the result, thus: 10 2 = 100 therefore log. == 2. 1( VM2 = 263 " r = 2.42 ]0-2-42 = .0263 " " = 2.42 To multiply by the aid of logarithms add the logarithms of the numbers together and find the corresponding number of the logarithm obtained. TO divide by the aid of logarithms subtract one logarithm from the other. To extract any root divide the logarithm by the index of the root and find the corre- sponding number of the logarithm obtained. To raise a number to any power multiply the logarithm of the Number by the index of the power, and find the corresponding number of the logarithm obtained. To find proportion by the aid of logarithms add together the logarithms of the second and third ter^is and subtract th logarithm of the first term; the answer is the correspond- ing number of the logarithm obtained. MATHEMATICAL TABLES. 357 VALUES OF SQUARES, CUBES, SQUARE ROOTS, AND CUBE ROOTS OF NUMBERS 1 TO 100. No. Square. Cube. Square Root. Cube Root. No. Square. Cube. Square Root. Cube Root. 1 1 1 1.0 1.0 51 2601 132651 7.14143 3.7084 2 4 8 1.41421 1.2599 52 2704 140608 7.21110 3.7325 3 9 27 1.73205 1.4422 53 2809 148877 7.28011 3.7563 4 16 64 2.0 1.5874 54 2916 157464 7.34847 3.7798 5 25 125 2.23607 1.7100 55 3025 166375 7.4162 3.8030 6 36 216 2.44949 1.8171 56 3136 175616 7.48331 3.8259 7 49 343 2 . 64575 1.9129 57 3249 185193 7.54083 3.8485 8 64 512 2.82843 2.0 58 3364 195112 7.61577 3.8709 9 81 729 3.0 2.0801 59 3481 205379 7.68115 3.8930 10 100 1000 3.16228 2.1544 60 3600 216000 7.74597 3.9149 11 121 1331 3.31662 2.2240 61 3721 226981 7.81025 3.9365 12 144 1728 3.46410 2.28P4 62 3844 238328 7.87401 3.9579 13 169 2197 3.60555 2.3513 63 3969 250047 7.93725 3.9791 14 196 2744 3.74166 2.4101 64 4096 262144 8.0 4.0 15 225 3375 3.87298 2.4662 65 4225 274625 8.06226 4.0207 16 256 4096 .0 2.5198 66 4356 287496 8.12404 4.0412 17 289 4913 .12311 2.5713 67 4489 300763 8.18535 4.0615 18 324 5832 . 24264 2 . 6207 68 4624 314432 8.24621 4.0817 19 361 6859 . 35*90 2.6684 69 4761 328509 8.30662 4.1016 20 400 8000 .47214 2.7144 70 4900 343000 8 . 36660 4.1213 21 441 9261 .58258 2.7589 71 5041 357911 8.42615 4.1408 22 484 10648 . 69042 2.8020 72 5184 373248 8.48528 4.1602 23 529 .12167 .79583 2.8439 73 5329 389017 8.54400 4.1793 24 576 13824 .89898 2 . 8845 74 5476 405224 8.60233 4.1983 25 625 15625 5.0 2.9240 75 5625 421875 8.66025 4.2172 26 676 17576 5.09902 2.9625 76 5776 438976 8.71780 4.2358 27 729 19683 5.19615 3.0 77 5929 456533 8.77496 4.2543 28 784 21952 5.29150 3.0366 78 6084 474552 8.83176 4.2727 29 841 24389 5.38516 3.0723 79 6241 493039 8.88819 4.2908 30 900 27000 5.47723 3.1072 80 6400 512000 8.94427 4. 3089 31 961 29791 5.56776 3.1414 81 6551 531441 9.0 4.3267 32 1024 32768 5.65685 3.1748 82 6724 551368 9.05539 4.3445 33 1089 35937 5.74456 3.2075 83 6889 571787 9.11043 4.3621 31 1156 39304 5.83095 3.2396 84 7056 592704 9.16515 4.3795 35 1225 42875 5.91608 3.2711 85 7225 614125 9.21954 4.3968 36 1296 46656 6.0 3.3019 86 7396 636056 9.27362 4.4140 37 1309 50653 6.08276 3 . 3322 87 7569 658503 9.32738 4.4310 38 1444 54872 6.16441 3.S620 88 7744 681472 9 . 38082 4.4480 39 1521 59319 6.245 3.3912 89 7921 704969 9.43398 4.4647 40 1600 64000 6.3245G 3.4200 90 8100 729000 9.48683 4.4814 41 1681 68921 6.40312 3.4482 91 8281 753571 9.53939 4.4979 42 1764 74088 6.48074 3.4760 92 8464 778688 9.59166 4.5144 43 1849 79507 6.55744 3.5034 93 8649 804357 9.64365 4.5307 44 1936 85184 6 . 63325 3.5303 94 8836 830584 9.69536 4 . 5468 45 2025 91125 6.70820 3.5569 95 9025 857375 9 . 74679 4.5629 46 2116 97336 6.78133 3 . 5830 96 9216 884736 9 . 79796 4.5789 47 2209 103823 6.85565 3.6088 97 9409 912573 9.84886 4.5947 48 2304 110592 6.92820 3.6342 98 9604 941192 9.89949 4 . 6104 49 2401 117649 7.0 3.6593 99 9801 970299 9.94987 4 . 6261 50 2500 125000 7.07107 3.6840 100 10000 1000000 10.0 4.6416 358 AMERICAN GAS-ENGINEERING PRACTICE. VALUES OF n-K AND FOR NUMBERS FROM 1 TO 100. n nn "1 n nn *r n UK "1 1.0 3.142 0.7854 2(5.0 81.681 530.93 52.0 1()3.36 2123.72 1.5 4.712 1.7672 26.5 83.252 551.55 53.0 166.50 2206.19 2.0 6.283 3.1416 27.0 84.823 572.56 54.0 169.64 2290.22 2.5 7. 854 4.9087 27.5 86.394 593.96 55.0 172.78 2375.83 3.0 9.425 7.0686 28.0 87.965 615.75 56.0 175.93 2463.01 3.5 10.996 9.6211 28.5 89 . 535 637.94 57.0 179.07 2551.76 4.0 12.566 12.566 29.0 91.106 660.52 58.0 182.21 2642.08 4.5 14.137 15.904 29.5 92.677 683.49 59.0 185.35 2733.97 5.0 15.708 19.635 30.0 94.248 706.86 60.0 188.49 2827.44 5.5 17.279 23.758 30.5 95.819 730.62 61.0 191.63 2922.47 6.0 18.850 28.274 31.0 97.389 754.77 62.0 194.77 3019.07 6.5 20.420 33 . 183 31.5 98.960 779.31 63.0 197.92 3117.25 7.0 21.991 38.485 32.0 100.53 804.25 64.0 201 . 06 3216.99 7.5 23.562 44.179 32.5 102.10 829.58 65.0 204 . 20 3318.31 8.0 25.133 50.266 33.0 103.67 855.30 66.0 207.34 3421.20 8.5 26.704 56.745 33.5 105.24 881.41 67.0 210.48 3525.66 9.0 28.274 63.617 34.0 106.81 907.92 68.0 213.63 3631.69 9.5 29.845 70.882 34.5 108.38 934.82 69.0 216.77 3739.29 10.0 31.416 78.540 35.0 109.96 962.11 70.0 219.91 3848 . 46 10.5 32.987 86.590 35.5 111.53 989.80 71.0 223.05 3959.20 11.0 34.558 95.033 36.0 113.10 1017.88 72.0 226.19 4071.51 11.5 36.128 103.87 36.5 114.67 1046.35 73.0 229.33 4185.39 12.0 37.699 113.10 37.0 116.24 1075.21 74.0 232.47 4300.85 12.5 39.270 122.72 37.5 117.81 1104.47 75.0 235.62 4417.87 13.0 40.841 132.73 38.0 119.38 1134.11 76.0 238.76 4536.47 13.5 42.412 143.14 38.5 120.95 1164.16 77.0 241.90 4656.63 14.0 43.982 153.94 39.0 122.52 1194.59 78.0 245.04 4778.37 14.5 45.553 165.13 39.5 124.09 1225.42 79.0 248.18 4901 . 68 15.0 47.124 176.72 40.0 125.66 1256.64 80.0 251.32 5026.56 15.5 48.695 188.69 40.5 127.23 1288.25 81.0 254.47 5153.01 16.0 50.265 201 . 06 41.0 128.81 1320.25 82.0 257.61 5281.03 16.5 51.836 213.83 41.5 130.38 1352.65 83.0 260.75 5410.62 17.0 53 . 407 226.98 42.0 131.95 1385.44 84.0 263.89 5541.78 17.5 54.978 240.53 42.5 133.52 1418.63 85.0 267.03 5674.50 18.0 56.549 254.47 43.0 135.09 1452.20 86.0 270.17 5808.81 18.5 58.119 268.80 43.5 136.66 1486.17 87.0 273.32 5944.69 19.0 59.690 283.53 44.0 138.23 1520.53 88.0 276.46 6082.13 19.5 61.261 298.65 44.5 139.80 1555.28 89.0 279.60 6221.13 20.0 62.^32 314.16 45.0 141.37 1590.43 90.0 282.74 6361.74 20.5 64.403 320.06 45.5 142.94 1625.97 91.0 285.88 6503.89 21.0 65.973 346.36 46.0 144.51 1661.90 92.0 289.02 6647.62 21.5 67.544 363.05 46.5 146.08 1698.23 93.0 292.17 6792.92 22.0 69.115 380.13 47.0 147.65 1734.94 94.0 295.31 6939 . 78 22.5 70.686 397.61 47.5 149.23 1772.05 95.0 298.45 7088.23 23.0 72.257 415.48 48.0 150.80 1809.56 96.0 301.59 7238.24 23.5 73.827 433.74 48.5 152.37 1847.45 97.0 304.73 7389.83 24.0 75.398 452.39 49.0 153.94 1885.74 98.0 307.87 7542.98 24.5 76.969 471.44 49.5 155.51 1924.42 99.0 311.02 7697.68 25.0 78.540 490.87 50.0 157.08 1963.50 100.0 314.16 7854.00 25.5 80.111 510.71 51.0 160.22 2042.82 MATHEMATICAL TABLES. 359 IMPORTANT VALUES OF x. = 3.14159 Log. 0.4971499" ^* = 1.46459 Log. . 1657160" = 0.10132 = 9.8696 1.0056952" 0.9942996" -0.31831 7C V =0.54619 n 3.5028503" I. 7373437" - 1.77245 0.2485749" ^-=0.785398 1.8950899'* = 31.00628 1.4914496" -| = 0.52359 I. 7189986" AREAS AND VOLUMES OP BODIES. Volume of rectangular vessel = o6c, where a, 6 and c are the three dimensions. Area of triangle = base X height. Area of circle ^d 2 =xr 2 . r = radius. =0.7851. Area of ellipse = trans verse axisX . 7854 X con jugate axis=ra&, where a and & are lengths of the two semi-axes. Surface of sphere =?rd 2 = 4;rr 2 . d = diameter. 4^ = 12.5664. Surf ace of cy Under = area of both ends X length X diameter. Surface of cone = area of base + circumference of baseXi slant height. Volume of sphere=4>rt*. |* = 4. 1888=^X0. 5236, i.e., -|<#. 66 o Volume of cylinder =xr 2 h. r radius of base, h = height. Volume of cone or pyramid = area of baseXi perpendicular height. Volume of frustum of cone = 0.26 18 H(D*+cP+Dd) t where D and d = diameters of each end, and H = perpendicular height. Volume of cask considered as middle frustum of a prolate spheroid: D = diameter of cylinder equal in volume and length to cask. B = diameter at bung. H (or H ') = diameter at head. Or (approximately) : Ascertain the difference between B and H, and multiply it by .7 (or .68 if less than 6 inches); add the product to H to obtain diameter of required cylinder. Or Capacity in gallons =. 00141 02 L(HH' + B 2 ). L = length. All the measurements are of course internal. PHYSICAL. To convert Degrees of Twaddle's hydrometer into S.G. (water = 1000), multiply by 5, and add S.G. (water = 1000) into degrees Twaddle, subtract 1000, and divide by 5. S.G., air-lto8.G.,#-l, multiply by 14.43S. S.G., H = 1 to S.G., air = l, multiply by 0.06926. Weight in air to weight in vacuo: P = weight required in vacuo. q = weight in air. V = volume of body weighed. v^= volume of the weignts. = specific gravity of air (weight of one cubic unit). 360 AMERICAN GAS-ENGINEERING PRACTICE. TABLE SHOWING THE AREAS OF CIRCLES IN IMPERIAL GALLONS CORRE- SPONDING TO DIAMETERS IN IMPERIAL INCHES. By the area in gallons is meant the number of gallons which are contained by a cylin- der having the circle as base, and a height of one inch. This table can be employed for calculating the area of ellipses, according to the formula Area= ~ 9 a ~ , where a is the area of the circle, having the transverse diameter of the ellipse as its diameter, B the area of corresponding circle for the congregate diameter, and (aB} the area of R circle having the difference between the transverse and congregate diameters as its diameter, the various diameters being expressed in inches. Diam. in Ins. 1 2 3 4 5 6 7 S 9 1 .002s .0034 .0040 .0047 .0055 .0063 .0072 .0081 .0091 .0102 2 .0113 .0124 .0137 . 0149 .0163 .0177 .0191 .0206 .0222 .0238 3 .0254 .0272 .0290 .0308 .0327 .0346 .0367 .0387 .0409 .0430 4 .0153 .0476 .0499 .0523 .0548 .0573 .0599 .0625 .0652 .0680 5 .0708 .0736 .0765 .0795 .0825 .0856 .0888 .0920 .0952 .0986 6 .1019 .1053 . 1088 .1124 .1160 .1196 .1233 .1271 .1309 . 1348 7 .1387 .1427 .1468 .1509 .1551 .1593 .1636 .1679 .1723 .1767 8 .181? .1858 .1901 . 1951 .1998 .2046 .2094 .2143 .2193 .2243 9 .2204 .2345 .2397 .2449 .2502 .2556 .2610 .2665 .2720 .2776 10 .2832 .2889 .2947 .3005 .3063 .3122 .3182 .3243 .3303 .3365 11 .3427 .3490 .3553 .3616 .3681 .3746 .3811 .3877 .3944 .4011 12 .4078 .4147 .4215 . 4285 .4355 .4425 .4496 .4568 .4640 .4713 13 .4787 .4860 .4935 .5010 .5086 .5162 .5239 .5316 .5394 .5472 14 .5551 .5631 .5711 .5792 .5873 .5955 .6037 .6120 .6204 .6288 15 .6373 .6458 .6544 .6630 .6717 .6805 .6893 .6982 .7071 .7161 16 .7251 .7342 .7433 .7525 .7618 .7711 .7805 .7899 .7994 .8090 17 .8186 .8282 .8379 .8477 .8575 .8674 .8774 .8874 .8974 .9075 18 .9177 .9279 .9382 .9485 .9589 .9694 .9799 .9905 .0011 .0118 19 1.0225 .0333 1.0441 1.0551 .0660 .0770 1.0881 1.0992 .1104 .1217 20 1.1330 .1443 1.1558 1.1672 .1788 .1903 .2020 1.2137 .2254 .2372 21 1.2491 .2610 .2730 1.2851 .2972 .3093 .3215 1 .3338 .3461 .3585 22 1.3709 .3834 .3960 1.4086 .4212 .4339 .4467 1.4595 .4724 .4854 23 1.4984 .5114 1.5246 1.5377 .5510 .5642 .5776 1.5910 .6044 .6179 24 1.6315 .6451 .5588 1.6726 .6863 7002 .7141 1.7281 .7421 1.7562 25 1.7703 .7845 .7987 1.8131 1.8274 1.8418 1.8563 1.8708 .8854 1.9001 26 1.9148 1.9295 1.9443 1.9592 1.9741 1.9891 2.0042 2.0193 2.0344 2.0496 27 2.0049 2.0802 2.0956 2.1110 2.1265 2.1421 2.1577 2.1734 2.1891 2.2049 28 2.2207 2.2366 2.2525 2.2685 2.2846 2.3007 2.3169 2.3331 2.3494 2.3657 29 2.3821 2.39S6 2.4151 2.4317 2.4483 2.4650 2.4817 2.4985 2.5154 2.5323 30 2.5473 2.5663 2.5834 2.6005 2.6177 2.6349 2.6523 2.6696 2.6870 2.7045 31 2.7221 2.739P 2.7573 2.7750 2.7928 2.8106 2.8284 2.8464 2.8644 2.8824 32 2.9005 2.9187 2.9369 2.9551 2.9735 2.9919 3.0103 3.0288 3.0473 3.0660 33 3.0846 3.1033 3.1221 3.1410 3.1599 3.1788 3.1978 3.2169 3.2360 3.2552 34 3.2744 3.2937 3.3130 3.3324 3.3519 3.3714 3.3910 3.4106 3.4303 3 4500 35 3.4698 3.4897 3.5096 3.5296 3.5496 3.5697 3.5898 3.6100 3.6303 3.6506 36 3.6710 3.6914 3.7119 3.73?4 3.7520 3.7736 3.7943 3.8151 3.8359 3.8568 37 3.8777 3.8987 3.9198 3.9409 3.9620 3.9833 4.0045 4.0259 4.0472 4.0687 38 4.0902 4.1117 4.1334 4.1550 4.1767 4.1985 4.2204 4.2423 4.2642 4.2862 39 4.3083 4.3304 4.3526 4.3748 4.3971 4.4195 4.4419 4.4643 4.4869 4.5094 40 4.5321 4.5548 4.5775 4.6003 4.6232 4.6461 4.6690 4.6921 4.7152 4.7383 41 4.7615 4.784S 4.8081 4.8314 4.8549 4.8783 4.9019 4.9255 4.9491 4.9728 42 4.9966 5.0201 5.0443 5.0682 5.0922 5.1163 5.1404 5.1645 5.1888 5.2130 43 5.2374 5.2618 5.2862 5.3107 5.3353 5.3599 5.3846 5.4093 5.4341 5.4589 44 5.483S 5.50SS 5.533S 5.55S8 5.5S40 5.6091 5.6344 5.6597 5.6850 5.7104 45 57359 5.7614 5.7870 5.8126 5.8383 5.8641 5.8899 5.9157 5.9417 5.9676 MATHEMATICAL TABLES. 361 AREAS OF CIRCLES IN IMPERIAL GALLONS FROM DIAMETERS Continued. Diam. in Ins. 1 2 3 4 5 6 7 8 9 46 5.9937 6.0198 6.0459 6.0721 6.0984 6.1247 G.1510 6.1775 6.2040 6.2305 47 6.2571 6.2838 6.3105 6.3372 6.3641 6.3909 6.4179 6.4449 6.4719 6.4990 48 6.5262 6.5534 6.5807 6.6080 6.6354 6.6629 6.6904 6.7179 6.7455 6.7732 49 6.8010 6.8287 6.8566 6.8845 6.9124 6.9405 6.9685 6.9967 7.0248 7.0531 50 7.0814 7.1097 7.1381 7.1666 7.1951 7.2237 7.2524 7.2810 7.3098 7.3386 51 7.3675 7.3964 7.4254 7.4544 7.4835 7.5126 7.5418 7.5711 7.6004 7.6298 52 7.6592 7.6887 7.7183 7.7479 7.7775 7.8072 7.8370 7.8668 7.S967 7.9265 53 7.9566 7.9867 8.0163 8.0170 8.0772 8.1075 8.1378 8 1682 8.1987 8.2292 54 8.2597 8.2903 8.3210 8.351S 8.3825 8.4134 8.4443 8.4753 8.5063 8.5373 55 8.5685 8.5997 8.6309 8.6622 8.693. 8.7250 8.7564 8.7880 8.8196 8.8512 56 8.8829 8.9146 8.9465 8.9783 9.0102 9.0422 9.0743 9.1064 9.1385 9.1707 57 9.2030 9.2353 9.2677 9.3001 9.332] 9.3651 9.3977 9.4301 9.4631 9.4959 58 9.5287 9.5816 9.5945 9.6275 9.660:] 9.6937 9.7269 9.7601 9.7934 9.8267 59 9.8601 9.8933 9.927J 9.9807 9.9943 10.0280 10.0617 10.0995 10.1293 10.1632 60 10.1972 10.2312 10.2653 10.2994 10.3336 10.3679 10.4022 10.4365 10.4709 10.5054 61 10.5399 10 5745 10.6092 10.6439 10.6786 10.7134 10.7483 10.7832 10.8182 10.8533 62 10.S884 10.9235 10.9537 10.9940 11.0293 11.0647 11. 1001; 11. 1356 11.1712 11.2068 63 11.2424 11.2781 11.3139 11.3497 11.3356 11.4216 11.4576 11.4936 11.5293 11.5659 64 11.6022 11.6334 11.6748 11.7112 11.7476 11.7842 11.8207 11.8573 11.8940 11.9308 65 11.9676 12.0044 12.0413 12.0783 12.1153 12.1524 12.1895 12.2267 12 2640 12.3013 66 12.3386 12.3760 12.4135 12.4511 12.4886 12.5263 12.5640 12.6017 12.6396 12.8774 67 12.7154 12.7533 12.7914 12.8295 12.8676 12.9058 12.9441 12.9824 13.0203 13.0593 68 13.0978 13.1353 13.1749 13.2136 13.2523 13.2911 13. 3299' 13.3388 13.407,^ 13.4468 69 13.4853 13.52 49 13.5641 13.6033 13.0126 13.6320 13.7214 1 13.7603 13.8003 13 8399 70 13.8795 13.9192 13.9590 13.993S 14.0386 14.0785 14.1185 14.1585 14.1986 14.2387 71 14.27S9 14.3192 14.3595 14.3999 14.4403 14.480S 14.5213 14.5819 14.6025 14.6432 72 14.6840 14.7248 14.7657 14.8036 14.8476 14.8886 14.9297, 14.9709 15.0121 15.0534 73 15.0947 15.1361 15.1775 15.2190 15.2606J 15.3022 15.343915.3356 15.4274 15.4692 74 15.5111 15.5531 15.5951 15.6371 15.6792J 15. 7214 15.70371 15.8059 15.8483 15.8907 75 15.9332 15.9757 15.0182 16.0609 16.1036 16.1463 16.1891 16.2320 16.2749 16.3179 76 16.3609 16. 40 JO 16.4471 16.4903 16.5336 16.5769 16.6202 16.6637 16.7071 16.7507 77 16.7943 16.8379 16.8816 16.9254 16.9092 17.0131 17.0570 17.1010 17.1450 17.1891 78 17.2333 17.2775 17.3218 17.3661 17.4105 17.4550 17.4995 17.5440 17.5386 17.0333 79 17.6780 17.7228 17.7676 17.8125 17.8575 17.9025 17.9478 17.9927 18.0379 18.0831 80 18.1284 18.1738 18.2192 18.2646 18.3101 18.3557 18.4013 18.4470 18.4928 18.5386 81 18.5S44 13.6301 18.6763 18.7224 18.7684 18.8146 18.8608 18.9079 18.9534 18.9997 82 19.0462 10.0926 19.1392 19.1858 19.2324 19.2791 19.3259:19.3727 19.4198 19.4665 83 19.5135 19.. C 608 19.6077 19.6548 19.7021 19.7493 19.7967 19.8441 19.8915 19.9390 84 19.9860 20.0342 20.0819 20.1296 20.1774 20.2252 20.2731 20.3211 20.3691 20.4171 85 20.4653 20.5135 20.5617 20.6100 20.6583 20.7007 20.7552 20.8037 20.8523 20.9096 86 20.9198 20.9934 21.0172 21.0961 21.1450 21.1940 21.2430 21.2921 21.3412 21.3904 87 21.4397 21.4890 21.5384 21 .5878 21.6373J21.686S 21.7364 21.7861 21.8358 21.8856 88 21.935* 21 .9853 21 0352 22.0852 22. 1352 122. 1854 22.2355 22.2857 22.3360 22.3863 89 22.4367 22.4872 22.5377 22.5883 22.6389 22.6895 22.740322.7911 22.8419 22.8928 90 22.9138 22.9948 23.0459 23.0970 23.1482 23.1994 23.2507 23.3021 23.3535 23.4049 91 23.4565 23.50SO 23.5597 23.6114 23.6631 23.7149 23.7668 23.8187 23.8707 23.9227 92 23.974S 24.0270 24.0792 24.1314 24.1838 24.2361 24.288624.3411 24.39S6 24.4462 93 24.4939 21.5516 24.6043 24.6572 24.7100 24.7630 24.8160 24.8690 24.9222 24.9753 94 25.02S5 25.0S18 25.1352 25.1886 25.2420 25.2955 25.3491 25.4027 25.4564 25.5101 95 25.5639 25.6177 25.6717 25 7256 25.779025.8337 25.8878 25.9420 25.9963 25.0506 96 26.1049 26.1593 26.213? 26.2683 26.3229l26.3776 20.4323 20.4870 26.5418 26.5967 97 26.6516 26.7C66 26.7610 26.^167 26.8719^26.9271 26.9823 27.0377 27.0930 27.1485 98 27.2040 27.2595 27.3151J27.3708 27.4265,27.4823 27.5381 27.5940 27.6499 27.7059 99 27.7620 27.8181 27.8743i 27.9305 27.9868 I 28.0431 28.0995 28.1500 28.2125 28.2690 100 28.3257 28.3823 28.4391 28.4959 28.5527 28.6096 28.6666 28.7236 28.7807 28.8378 362 AMERICAN GAS-ENGINEERING PRACTICE. AREAS OF CIRCLES IN IMPERIAL GALLONS FROM DIAMETERS Continued. Diam. in Ins. 1 2 3 4 5 6 7 8 9 101 28.8950 28.9522 29.0096 29.0669 29.1243 29.1818 29.2393 29.2969 29.3546 29.4123 102 29.4700 29.5278 29.5857 29.6436 29.7016 29.7596 29.8177 29.8759 29.9341 29.9924 103 30.0507 30.1091 30.1675 30.2260 30.2845 30.3432 30.4018 30.4695 30.5193 30.5781 104 30.6370 30.6960 30.7550 30.8140 30.8732 30.9323 30.9916 31.0508 31.1102 31.1696 105 31.2290 31.2886 31.3481 31.4077 31.4674 31.5272 31.5870 31.6468 31.7067 31.7667 106 31.8267 31.8868 31.9469 32.0071 32.0674 32.1277 32.1880 32.2485 32.3089 32.3695 107 32.4301 32.4907 32.5514 32.6122 32.6730 32.7338 32.7948 32.855S 32.9168 32.9779 108 33.0391 33.1003 33.1615 33.2229 33.2842 33.3457 33.4072 33.4687 33.5303 33.5920 109 33.6537 33.7155 33.7773 33.8392 33.9012 33.9632 3 i. 0252 34.0874 34.1495 34.2118 110 34.2741 34.3364 34.3988 34.4613 34.5238 34.5863 34.6490 34.7117 34.7744 34.8372 111 34.9001 34.9630 35.0259 35.0890 35.1520 35.2152 35.2784 35.3416 35.4049 35.4683 112 35.5317 35.5952 35.6587 35.7223 35.7860 35.8497 35.9134 35.9772 36.0411 36.1051 113 36.1690 36.2331 36.2972 36.3613 36.4256 36.4898 36.5542 36.6185 36.6830 36.7475 114 36.8120 36.8766 36.9413 37.0030 37.0708 37.1357 37.2006 37.2655 37.3305 27.3956 115 37.4607 37.5259 37.5911 37.6564 37.7217 37.7871 37.8526 37.9181 37.9837 38.0493 116 38.1150 38.1808 38.2466 38.3124 38.3783 38.4413 38.5103 38.5764 38.6426 38.7088 117 38.7750 38.8413 38.9077 38.9741 39.0406 39.1071 39.1737 39.2404 39.3071 39.3738 118 39.4407 39.5075 39.5745 39.6415 39.7085 39.7756 39.8428 39.9100 39.9773 40.0146 119 40.1120 40.1791 40.2469 40.3145 40.3821 40.4498 40.5175 40.5853 40.6531 40.7210 120 40.7890 40.8570 40.9250 40.9932 41.0613 41.1296 41.1979 41.2662 41.3346 41.4031 121 41.4716 41.5402 41.6088 41.6775 41.7463 41.8151 41.8839 41.9528 42.0218 42.0908 122 42.1599 42.2291 42.2983 42.3675 42.4368 42.5062 42.5756 42.6451 42.7147 42.7843 123 42.8539 42.9236 42.9934 43.0532 43.1331 43.2030 43.2730 43.3131 43.4132 43.4833 124 43.5536 43.623? 43.6942 43.7646 43.8350 43.9055 43.9761 44.0467 44.1173 14.1881 125 44.2589 44.3297 44.4006 44.4716 44.5426 44.6136 44.6848 44.7560 44.8272 44.8985 126 44.9693 45.0412 45.1127 45.1842 45.2558 45.3275 15.3991 45.4709 45.5427 45.6146 127 45.6865 45.7585 45.8305 45.9026 45.9747 46.0469 46.1192 46.1915 46.2639 46.3363 128 46.4088 46.4813 46.5539 46.6266 46.6993 46.7721 46.8449 46.9178 46.9907 47.0637 129 47.1368 47.2099 47.2830 47.3563 47.4295 47.5029 47.5763 47.6497 47.7232 47.7968 130 47.8704 47.9441 48.0178 48.0916 48.1654 48.2392 48.3133 48.3873 48.46H 18.5355 131 48.6097 48.6839 48.7582 48.8326 48.9070 48.9815 49.0560 49.1306 49.2052 49.2799 132 49.3547 49.4295 49.5043 49.5793 49.6542 49.7293 49.8014 49.8795 49.9547 50.0300 133 50.1053 50.1807 50.2561 50.3316 50.4071 50.4827 50.5584 50.0341 50.7099 50.7857 134 50.8616 50.9375 50.0135 51.0896 51.1657 51.2419 51.3181 51.3944 51.4707 51.5471 135 51.6235 51.7001 51.7766 51.8532 51.9299 52.0067 52.0834 52.1003 52.2372 52.3142 136 52.3912 52.4682 52.5454 52.6226 52.6998 52.7771 52.8545 52.9319 53.0094 53.0869 137 53.1645 53.2421 53.3198 53.3976 53.4754 53.5532 53.6312 53.7091 53.7872 53.8653 138 53.9434 54.0216 54.0999 54.1782 54.2566 54.3350 54.4135 54.4921 54.5707 54.6493 139 54.7280 54.8068 54.8856 54.9645 54.0435 55.1225 55.2015 55.2807 55.'359^ 55.4390 140 55.5183 55.5977 55.6771 55.7565 55.8360 55.9156 55.9952 56.0749 56.1546 56.2344 141 56.3143 56.3942 56.4742 56.5542 56.6343 56.7144 56.7946 56.8748 56.9551 57.0355 142 57.1159 57.1964 57.2769 57.3575 57.4381 57.5188 57.5996 57.6804 57.7613 57.8422 143 57.9232 58.0042 58.0853 58.1065 58.2477 58.3290 58.4103 58.4917 58.5731 58.6546 144 58.7361 58.8177 58.8994 58.9811 58.0629 59.1447 59.2286 59.3086 59.3905 59.4726 145 59.5547 59.6369 59.7191 59.8014 59.8838 59.9662 60.0486 60.1311 60.2137 60.2963 146 60.3790 60.4618 60.5446 60.6274 60.7103 60.7933 60.8763 60.9594 60.0425 61.1257 147 61 .2090 61.2923 61.3756 61.4591 61.5425 61.6261 61.7097 61.7933 61.8770 01.9608 148 62.0446 62.1284 62.2124 62.2964 62.3804 62.4615 62.5487 62.6329 62.7171 62.8015 149 62.8858 62.9703 63.0548 63.1393 63.2239 63.3086 63.3933 63.4781 63.5629 63.6478 150 63.7328 63.8178 63.9029 63.9880 64.0731 64.1584 64.2437 64.3290 64.4144 64.4999 151 64.5854 64.6710 64.7566 64.8423 64.9280 65.0138 65.0997 65.1856 65.2716 85.3576 152 65.4437 65.5298 65.6160 65.7022 65.7886 65.8749 65.9613 65.0478 66.1344 66.2209 153 66.3076 66.3943 66.4811 66.5679 66.6548 66.7417 66.8287 66.9157 67.002S 07.0900 154 67.1772 67.2645 67.3518 67.4392 67.5266 67.6141 67.7017 67.7893 67.8770 67.9617 155 68.0525 68.1403 68.2282 68.3161 68.4041 68.4922 68.5803 68.6685 68.7567 68.8450 MATHEMATICAL TABLES. 363 AREAS OF CIRCLES IN IMPERIAL GALLONS FROM DIAMETERS Continued. Diam. in Ins 1 2 3 4 5 6 7 8 9 156 68.9334 69.021S 69.1103 69.1988 69.2873 69.3760 69.4647 69.5534 69.6422 69.7311 157 69.8200 69.9090 69.9980 70.0871 70.1762 70.2654 70.3547 70.4440 70.5333 70.6228 158 70.7122 70.8018 70.8914 70.9810 71.0707 71.1605 71.2503 71.3402 71.4301 71.5201 159 71.6102 71.7003 71.7904 71.8805 71.9709 72.0613 72.1516 72.2421 72.3326 72.4231 160 72.5138 72.6044 72.6952 72.7859 72.8768 72.9677 73.0586 73.1496 73.2407 73.3318 161 73.4230 73.5142 73.6055 73.6969 73.7883 73.8798 73.9713 74.0629 74.1515 74.2462 162 74.3379 74.4297 74.5216 74.6135 74.7055 74.7975 74.8896 74.9817 75.0739 75.1662 163 75.2585 75.3509 75.4433 75.5358 75.6283 75.7209 75.8136 75.9063 75.9991 76.0919 164 76.1848 76.2777 76.3707 76.4637 76.5569 76.6500 76.7432 76.8365 76.929^ 77.0232 165 77.1167 77.2102 77.3037 77.3974 77.4910 77.5848 77.6786 77.7724 77.8663 77.9603 166 78.0543 78.1483 78.2425 78.3366 78.4309 78.5252 78.6195 78.7139 78.8084 78.9029 167 78.9975 79.0921 79.1868 79.2816 79.3764 79.4713 79.5662 79.6612 79.7562 79.8513 16^ 79.9464 80.0416 80.1369 80.2322 80.3276 80.4230 80.5185 80.6140 80.7096 80.8053 169 80.9010 80.9988 81.0926 81.1885 81.2844 81.3804 81.4765 81.5726 81.6687 81.7650 170 81.8612 81.9576 82.0540 82.1501 82.2469 82.3435 82.4401 82.5368 82.6335 82.7303 171 82.827) 82.9240 83.0210 83.1180 83.2151 83.3122 83.4094 83.5067 83.6039 83.7013 172 83.7987 83.8962 83.9937 84.0913 84.1889 84.2866 84.3844 84.4822 84.5801 84.6780 173 84.7760 84.8740 84.9721 85.0702 85.1684 85.2667 85.3650 85.4634 85.5618 85.6603 174 85.7589 85.8575 85.9561 86.0548 86.1536 86.2524 86.3513 86.4503 86.549? 86.6483 175 86.7474 86.8466 86.9458 87.0451 87.1444 87.2438 87.3433 87.4428 S7.5424 87.6420 '176 87.7417 87.8414 87.9412 88.0410 88.1409 88.2409 88.3409 88.4410 88.5411 88.6413 177 88.7416 88.8419 88.9422 89.0426 89.1431 89.2436 89.3442 89.4449 89.5455 89.6463 178 89.7471 89.8480 89.9489 90.0499 90.1509 90.2520 90.3532 90.4544 90.5556 90.6570 179 90.7583 90.8593 90.9613 91.0628 91.1644 91.2661 91.3678 91.4696 91.5714 91.6733 180 91.7752 91.8772 91.9793 92.0814 92.1836 92.2858 92.3881 92.4904 92.5928 92.6953 181 92.7978 92.9001 93.0030 93.1057 93.2084 93.3112 93.4140 93.5170 93.6199 93.7229 182 93.8260 93.9292 94.0323 94.1356 94.2389 94.3423 94.4457 94.5491 94.6527 94.7563 183 P4.8599 94.9636 95.0674 95.1712 95.2750 95.3790 95.4830 95.5870 95.6911 95.7952 184 95.8995 96.0037 96.1080 96.2124 96.3169 96.4214 P6.5259 96.6305 96.7352 96.8399 185 96.9447 97.0495 97.1544 97.2593 97.3644 97.4694 97.5745 97.6797 97.7849 97.8902 186 97.9956 98.1010 98.2064 98.3119 98.4175 98.523! 98.6288 98.7345 98.8403 98.9462 187 99.0521 99.1581 99.2641 99.3702 99.4763 99.5825 99.6888 99.7951 99.9014 100.0078 188 100.1143 100.2209 100.3274 100.4341 100.5403 100.6476 100.7544 100.8612 100.9682 101.0752 189 101.1822 101.2893 101.3965 101.5037 101.6109 101.7183 101.8256 101.9331 102.0406 102.1481 190 102.2557 102.3634 102.4711 102.5789 102.6868 102.7946 102.9026 103.0106 103.1187 103.2268 191 103.3350 103.4432 103. 551 5 103.6598 103.7682 103.8767 103.9852 104.0938 104.2024 104.3111 192 104.4198 104.5?86 104.6375 104.7464 104.8554 104.9644 105.0735 105.1826 105.2918 105.401 1 193 105.5104 105.6197 105.7292 105.8386 105.9482 106.0578 106.1674 106.2771 106.3869 106.49P7 194 106.6066 106.7 165 106.8265 106.9365 107.046P, 107.1568 107.2670 107.3773 107.4876 107.5980 195 107.7084 107.8189 107.9294 108.0401 108.1508 108.2615 108.3723 198.4831 108.5940 108.7050 190 108.8160 108.9270 109.0382 109.1493 109.2606 109.3719 109.4832 109.5946 109.7061 109.8176 197 109.9292 110.040S 110.1525 110.2642 110.3760 110.4879 110.5998 110.7118 1 10.8238 110.9359 198 111.0480 111.1602 111.2725 111.3848 111.4972 111.6096 111.7221 111.8346 111.9472 112.0599 199 112.1726 112.2853 112.3982 112.5110 112.6240 112.7370 112.8500 112.9631 113.0763 113.1895 200 113.3028 113.4161 113.5295 113.6429 113.7564 113.'8700 113.9836 114.0973 114.2110 114.3248 364 AMERICAN GAS-ENGINEERING PRACTICE. TABLE SHOWING THE AREAS OF SEMI- SQUARES IN IMPERIAL GALLONS CORRESPONDING TO SIDES IN IMPERIAL INCHES. This table shows the number of gallons contained in a prism haying the semi-square described on the side as base, and a height of one inch. It is of use in finding the area in gallons of a rectangle. The area is aXb, a and b being the sides of the rectangle. But =+ ~ "Rules. Add the area of the semi-square on the longer side of the rectangle to the area of the semi-square on the shorter side, and from the sum deduct the semi-square on a line equal to the difference between the two sides, dimensions being in inches. Sides in Ins. 1 .00002 2 .00007 3 .00016 4 .00029 5 1.00045 6 .00065 7 .00088 8 .00115 9 .00146 1 .0018 .0022 .0026 .0030 .003.0 .0041 .0046 .0052 .0058 .0065 2 .0072 .OOSO .0087 .0095 .0101 .0113 .0122 .0131 .0141 .0152 3 .0162 .0173 .0185 .0196 .0203 .0221 .0234 .0247 .0260 .0274 4 .0289 .0303 .0318 .0333 .0349 .0365 .0382 .0398 .0415 .0433 5 .0451 .0469 .0488 .0507 .0526 .0545 .0566 .0586 .0607 .0628 6 .0649 .0671 .0693 .071fl .7390 .0762 .0786 .0809 .0834 .0859 7 .0884 .0909 .0935 .0961 .0987 .1014 .1042 .1009 .1097 .1125 8 .1154 .1183 .1213 .1242 .1272 .130?. .1334 .1265 .1396 .1428 9 .1461 .1493 .1526 .1560 .1593 .1627 .1662 .1697 .1732 .1767 10 .1803 .1840 .1876 .1913 .1950 .1988 .2026 .2065 .2103 .2142 11 .2182 .2222 .2262 .2303 .2344 .2385 .242P .2468 .2511 .255* 12 .2597 .2640 .2684 .2728 .2773 .2818 .2863 .2908 .2954 .3001 13 .3048 .3095 .3142 .3190 .3238 .3286 .3335 .3385 .3434 .3484 14 .3534 .3585 .3636 .3688 .3739 .3791 .3844 .3897 .3950 .4003 15 .4057 .4112 .4166 .4221 .4277 .4332 .4388 .4445 .4502 .4559 16 .4616 .4674 .4733 .4791 .4850 .4909 .4969 .5029 .5090 .5150 17 .5211 .5273 .5335 .5297 .5460 .5523 .5586 .5649 .5713 .5778 18 .5843 .5908 .5973 .6039 .6105 .6172 .6239 .6306 .6373 .6441 19 .6510 .6579 .6648 .1)717 .6787 .685? .6927 .6998 .7070 .7141 20 .7213 .7285 .7358 .7431 .7504 .7578 .7652 .7727 .7802 .7877 21 .7952 .8028 .8105 .8181 .8258 .8336 .8413 .8491 .8570 .8649 22 .8728 .8807 .8887 .8967 .9048 .9129 .9210 .9292 .9374 .9457 23 .9539 .9622 .9706 .9790 .9874 .9959 .0043 1.0129 1.0214 1.0300 24 1.0387 1.0474 1.0561 1 .0648 1.0736 .0824 .0913 1.1002 1.1091 1.1180 25 1.1270 1.1361 .1451 1.1543 1.1634 .1720 .1818 1.1910 1.2003 1.2097 26 1.2190 .2284 ' .2378 1.2473 1.2568 .2663 .2759 1.2855 1.2952 1 .3049 27 1.3146 .3243 .3341 1.3440 1 .3538 1.3637 .3737 1.3836 1.3936 1.4037 28 1.4138 .4239 .4340 1.4442 1 .4544 1.4647 .4750 1.4853 1.4957 1 .5061 29 1.5166 .5270 .5375 1.5481 1.5587 .5693 .5800 1.5906 1.6014 1.6121 30 1.6229 .6338 .6447 1.6556 1.6665 1.6775 1.6885 1.6996 1.7107 1.7218 31 1.7329 7441 1.7554 1.7666 1.7780 1.7893 .8007 1.8121 1.8235 1 .8350 32 1.8465 .8581 1 .8697 1.8813 1.8930 1.9047 .9164 1 .9282 1.9400 1.9519 33 1.9638 .9757 1.9876 1.9996 2.0117 2.0237 2.0358 2.0480 2.0601 2.0723 34 2.0846 2.0969 2.1092 2.1215 2.1339 2.1463 2.1588 2.1713 2.1838 2.1964 35 2.2090 2.2216 2.2343 2.2470 2.2598 2.2726 2.2854 2.2983 2.3111 2,3241 30 2.3370 2.3500 2.3631 2.3762 2.3893 2.4024 2.4156 2.4288 2.4421 2.4554 37 2.4687 2.4820 2.4954 25089 2.5223 2.5358 2.5494 2.5630 2.5766 2.5902 38 2.6039 2.6176 2.6314 2.6452 2.6590 2.6729 2.6868 2.7007 2.7147 2.7287 39 2.7428 2.7569 2.7710 2.7851 2.7993 2.8136 2.8278 2.8121 2.8565 2.8708 40 2.8852 2.8997 2.9142 2.9287 2.9432 2.9578 2.9724 2.9871 3.0018 3.0165 41 3.0313 3.0461 3.0609 3.0758 3.0907 3.1057 3.1207 3.1357 3.1507 3.1658 42 3.1810 3.1961 3.2113 3.2266 3.2418 3.2572 3.2725 3.2879 3.3033 3.3188 43 3.3342 3.349S 3.3653 3.3809 3.3966 3.4122 3.4279 3.4437 3.4595 3.4753 44 3.4911 3.5070 3.5229 3.5389 3.5549 3.5709 3.5870 3.6031 8.6192 3 6354 45 3.651P 3.6679 3.6842 3.7005 3.7168 3.7332 3.7496 3.7661 3.7826 3.7991 MATHEMATICAL TABLES. 365 AREAS OF SEMI-SQUARES IN IMPERIAL GALLONS Continued. Sides in Ins. 1 2 3 4 5 6 7 8 9 16 3.8157 3.8323 3.8490 3.8657 3.8824 3.8991 3.9159 3.9327 3.9496 3.9665 47 3.9834 .40004 4.0174 4.0344 4.0515 4.0686 4.0858 4.1030 4.1202 4.1374 48 4.1547 4.1721 4.1894 4.2068 4.2243 4.2417 4.2593 4.2768 4.2944 4.3120 49 4.3297 4.3473 4.3651 4.3828 4.4006 4.4185 4.4363 4.4542 4.4722 4.4902 50 4.5082 4.5262 4.5443 4.5624 4.5806 4.5988 4.6170 4.6353 4.6536 4.6719 51 4.6903 4.7087 4.7272 4.7456 2.7642 4.7827 4.8013 4.8199 4.8386 4.8573 52 4.8760 4.8948 4.9136 4.9325 4.9513 4.9703 4.9892 5.0082 5.0272 5.0463 53 5.0651 5.0845 5.1037 5.1229 5.1421 5.1614 5.1807 5.2001 5.2195 5.2389 54 5.2583 5.2778 5.2974 5.3169 5.3365 5.3562 5.3758 5.3955 5.4153 5.4351 55 5.4549 5.4747 5.4946 5.5146 5.5345 5.5545 5.5746 5.594C 5.6147 5.6349 56 5.6551 5.6753 5.6955 5.7158 5.7361 5.7565 5.7769 5.7973 5.8178 5.8383 57 5.8588 5.8794 5.9000 5.9207 5.9413 5.9621 5.9828 6.0036 6.0244 6.0453 58 6.0662 6.0871 6.10S1 6.1291 6.1502 6.1712 6.1924 6.2135 6.2347 6.2559 59 6.2772 6.2985 6.3198 6.3412 6.3626 6.3840 6.4055 6.4270 6.4486 6.4702 60 6.4918 6.5134 6.5351 6.5569 6.5786 6.6004 6.6223 6.6441 6.6660 6.6880 61 6.7100 6.7320 6.7540 6.7761 6.7983 6.8204 6.8426 6.8649 6.8871 6.9094 62 6.9318 6.9542 6.9766 6.9990 7.0215 7.0440 7.0666 7.0892 7.1118 7.1345 63 7.1572 7.1799 7.2027 7.2255 7.2484 7.2712 7.2942 7.3171 7.3401 7.3631 64 7.3862 7.4093 7.4324 7.4556 7.4788 7.5021 7.5253 7.5487 7.5720 7.5954 65 7.6188 7.6423 6.6658 7.6893 7.7129 7.7365 7.7601 7.7838 7.8075 7.8313 66 7.8550 7.8789 7.9027 7.9266 7.9505 7.9745 7.9985 8.0226 8.0466 8.0707 67 8.0949 8.1191 8.1433 8.1675 8.1918 8.2162 8.2405 8.2649 8.2893 8.3138 68 8.3383 8.3629 8.3874 8.4121 8.4367 8.4614 8.4861 8.5109 8.5357 8.5605 69 8.5854 8.6103 8.6352 8.6602 8.6852 8.7102 8.7353 8.7604 8.7856 8.8108 70 8.8360 8.8613 8.8866 8.9119 8.9373 8.9627 8.9881 9.0136 9.0391 9.0647 71 9.0903 9.1159 9.1416 9.1673 9.1930 9.2188 9.2446 9.2704 9.2963 9.3222 72 9.3482 9.3741 9.4002 9.4262 9.4523 9.4784 9.5046 9.5308 9.5570 9.5833 73 9.6096 9.6360 9.6624 9.6888 9.7152 9.7417 9.7682 9.7948 9.8214 9.8480 74 9.8747 9.9014 9.9282 9.9549 9.9818 10.0086 10.0355 10.0624 10.0894 10.1164 75 10.1434 10.1705 10.1976 10.2247 10.2519 10.2791 10.3063 10.3336 10.3609 10.3883 76 10.4157 10.4431 10.4706 10.4981 10.5256 10.5532 10.5808 10.6084 10.6361 10.6638 77 10.6916 10.7194 10.7472 10.7751 10.8030 10.8309 10.8589 10.8869 10.9149 10.9430 78 10.9711 10.9992 11.0274 11.0557 11.0839 11.1122 11.1405 11.1689 11.1973 11.2257 79 11.2542 11.2827 11.3113 11.3398 11.3685 11.3971 11.4258 11.4545 11.4833 11.5121 80 11.5409 11.5698 11.5987 11.6276 11.6566 11.6856 11.7147 11.7438 11.7729 11.8021 81 11.8313 11.8605 11.8898 11.9191 11.9484 11.9778 12.0072 12.0366 12.0661 12.0956 82 12.1252 12.1548 12.1844 12.2141 12.2438 12.2735 12.3033 12.3331 12.3629 12.3928 83 12.1227 12.4527 12.4827 12.5127 12.5428 12.57?9 12.6030 12.6332 12.6634 12.6936 84 12.7239 12.7542 12.7845 12.8149 12.8453 12.8758 12.9063 12.9368 12.9674 12.9980 85 13.0286 13.0593 13.0900 13.1208 13.1515 13.1824 13.2132 13.2441 13.2750 13.3060 86 13.3370 13.3680 13.3991 13.4302 13.4613 13.4925 13.5237 13.555C 13.5863 13.6176 87 13.6490 13.6803 13.7118 13.7432 13.7747 13.8063 13.8379 13.8695 13.9011 13.9328 88 13.9645 13.9963 14.0281 14.0599 14.0918 14.1237 14.1556 14.187C 14.2196 14.2516 89 14.2837 14.315S 14.3480 14.380:> 14.4124 14.4446 14.4769 14.509? 14.5416 14.5740 90 14.6065 14.6390 14.6715 14.7040 14.7366 14.7692 14.8019 14.8346 14.8673 14.9001 91 14.9329 14.9657 14.9986 15.0315 15.0644 15.0974 15.1304 15.1635 15.1966 15.2297 92 15.2629 15.2961 15.3293 15.3626 15.3959 15.4292 15.4626 15.4960 15.5295 15.5630 93 15.5965 15.6300 15.6636 15.6973 15.7309 15.7646 15.7984 15.8322 15.8660 15.8998 94 15.9337 15.9676 16.0016 16.0356 16.0696 16.1037 16.1378 16.1719 16.2061 16.2403 95 16.2745 16.3088 16.3431 16.3775 16.4119 16.4463 16.4807 16.5152 16.5498 16.5843 96 16.6189 16.6536 16.6883 16.7230 16.7577 16.7925 16.8273 16.8622 16.8971 16.9320 97 16.9670 17.0020 17.0370 17.0721 17.1072 17.1423 17.1775 17.2127 17.2480 17.2833 98 17.3186 17.3540 17.389* 17.4248 17.4603 17.4958 17.5313 17.5669 17.6025 17.6382 99 17.6739 17.7096 17.7453 17.7811 17.8170 17.8528 17.8887 17.9247 17.9606 17.9967 100 18.0327 18.0688 18.1049 18.1411 18.1773 18.2135 18.2497 18.2860 18.3224 18.3588 366 AMERICAN GAS-ENGINEERING PRACTICE. AREAS OF SEMI-SQUARES IN IMPERIAL GALLONS Continued. Sides in Ins. 1 2 3 4 5 6 7 8 9 101 18.3952 18 4316 18.4681 18.5046 18.5412 18.5777 18.6144 IS. 65 1C 18.6877 18.7245 102 18.7612 18.7980 18.8349 18.8717 18.9087 18.9456 18.9826 19.0191 19.0567 19."93S 103 19.1309 19.1681 19.2053 19.2425 19.2798 19.3171 19.3544 19.3918 19.4292 19.466/ 104 19.5042 19.5417 19.5793 19.6169 19.6545 19.6922 19.7299 19.7676 19.8054 19.8432 105 19.8811 19.9189 19.9569 19.9948 20.0328 20.0709 20.1089 20.1470 20.1852 20. 2233 106 20.2615 30.2998 20.3381 20.3764 20.414S 20.1531 20.4916 20.5300 20.5685 20.6071 107 20.6456 20.684.? 20.7229 20.7616 20.8003 20.8390 20.8778 20.9167 20.9555 20.9944 108 21.0333 21.0723 21.1113 21.1504 21.1894 21.2286 21.2677 21.3069 21.3461 21.3 54 109 21.4247 21.4640 21.5034 21.5428 21.5^22 21.6217 21.6012 21 .7007 21.7403 21.7799 110 21.8195 21.8593 21.8990 21.9388 21.9785 22.0184 22.0583 22 .0981 22.1381 22.1781 111 22.2181 22.2581 22.2982 22.3384 22.3785 22.4187 22.4589 22.499i 22.5395 22.5793 112 22.6202 22.6606 22.7011 22.7416 22.7821 22.8226 22.8632 22.9039 22.9445 22.9852 113 23.0260 23.0667 23.1075 23.1484 23.1893 23.2302 23.2711 23.3121 23.3531 23..3942 114 23.4353 23.4764 23.5176 23.5588 23.6000 23.6413 23.6826 23.7240 23.7654 23. 008 115 23.8483 23.8897 23.9313 23.9728 24.0144 24.0561 24.0978 24.1395 24.1812 24.2230 116 24.2648 24.3067 24.3486 24.3905 24.4324 24.4744 24.5165 24.5585 24.6006 24.6428 117 24.6850 24.7272 24.7694 24.8117 24.8540 24.8964 24.9388 24.9812 25.0237 25.0662 118 25.1087 25.1513 25.1939 25.2386 25.2793 25.3220 25.3647 25.407i 25.4503 25.4932 119 25.5361 25.5790 25.6220 25.6650 25.7081 25.7512 25.7943 25.837; 25.880o 25.9238 120 25.9671 26.0104 26.0537 26.0971 26.1405 26.1839 26.2274 26.270S 20.3145 26.3581 121 26.4017 26.4453 26.4890 26.5328 20.5765 26.6203 26.6542 26.708f 2G.751P 26.7959 122 26.8399 26.8839 26.9279 26.9720 27.0162 27.0603 27.1045 27.148* 27.1931 27.2373 123 27.2817 27.3201 27.3705 27.4149 27.4594 27.5089 27.5485 27.5931 27.6377 27.6824 124 27.7271 27.7718 27.8166 27.8614 27.9063 27.9511 27.9961 28.04K 28.0860 28.1310 125 28.1761 28.2212 28.2663 28.3115 28.3567 28.4020 28.4472 28.492( 28.5379 28.5833 126 28.6287 28.6742 28.7197 28.7652 28.8108 28.8564 28.9020 28.9477 28.9934 28.0392 127 29.0849 29.1303 29.1766 29.2225 29.2684 29.3144 29.3C04 29.406. r 29.4525 29.4986 128 29.5448 29.5910 29.6372 29 6834 29.7297 29.7761 J9.8224 29.868; 29.9152 29.9017 129 30.0082 30.0548 30.1013 30.1480 30.194C 30.2413 30.2880 30.334,' 30.3816 30.4284 130 30.4753 30.5222 30.5691 30.6161 30.6631 30.7101 30.7572 30.^,04; 30.8515 30.8987 131 30.9459 30.9932 31.0405 31.0878 31.1352 31.12fi 31.2300 31.277 31.3250 31.3726 132 31.4202 31.4678 31.5155 31.5631! 31.0109 31.65S7 31.7005 31.7545 31.8022 31.8501 133 31.8981 31.9460 31.9941 32.0421 32.0902 32.1383 32.1805 32.2347 32.2829 32.3312 134 32.3795 32.4279 32.4763 32.5247 32.5731 32.6216 32.6701 32.7187 32.7673 32.8159 135 42.8646 32.9133 32.9621 33.0108 33.0596 33.1085 33.1574 33.2003 33.2553 33.3043 136 43.3533 33.4024 33.4515 33.5006 33.5498 33.5990 33.6482 33.6975 33.74^)8 33.7962 137 33.8456 33.8950 33.9445 33.9940 34.0135 34.0931 31.1427 34.1923 34.2420 34.2917 138 34.3415 34.3913 34.4411 34.4910 35.5409 34.5908 34.6408 34.6908 34.7408 .34.7909 139 34.8410 34.8911 34.9413 34.9915 35. Oil.S 35.0921 35.1424 35.1928 35.2432 35.29.36 140 35.3441 45.3946 35.4452 35.4957 35.5464 35.597C 35.6477 ''5.6984 35.7492 35.8000 !41 35.8508 35.9017 35.95?0 36.0035 36.0545 36.1055 36.1560 30.2077 36.2588 36.3009 142 36.3611 36.4124 36.4636 36.5149 36.5663 36.6177 36.6691 30.7205 36.7720 36.8235 143 36.8751 36.9267 36.9783 37.0300 37.0817 37.1334 37.1852 37.2370 37.2888 .37.3407 144 37.3926 37.4446 37.4960 37.5480 37.600'] 37.6527 37.7049 37.7570 37.8092 37.8615 145 37.9138 37.9661 38.0184 38.0708 38.1232 38.1757 38.2282 38.2807 38.3.333 38.3859 14(5 38.4385 38.4912 3S.5439 38.5966 38.0494 38.7022 38.7551 38.8080 38.8609 38.9139 147 38.9069 39.0199 39.0730 39.1201 39.1792 39.2324 39.2850 39.3389 39.3922 39.4455 148 39.4988 39.5522 39.6057 39.0591 39.7126 39.7662 39.8197 39.8734 39.9270 39.9807 149 40.0344 40.0882 40.1420 40.1958 40.24% 40.3035 40.3575 40.4115 40.4055 40.5195 150 40.5736 40.6277 40.6819 40.7360 40.7903 40.8445 40.8988 40.9532 41.0075 41.0619 151 41.1164 41.1708 41.2254 41.2799 11.3345 41.3891 41.4438 41.4985 4 1 .5522 41 .6080 152 41.6628 41.7176 41.7725 41.8274 41.8823 41.9373 41.9923 41.0474 42 1025 42.1576 153 42.2128 42.2080 12.3232 42.3785 42.4338 42.4891 42.5445 42.5999 42.6554 42.7108 154 42.7664 42.8219 42.8775 42.9331 42.9888 43.0445 43.1003 43.1500 4.4.2118 43.2077 155 43.3236 43.3795 43.4354 43.4914 43.5475 43.6035 43.6596 43.7158 43.7719 43.8281 MATHEMATICAL TABLES. 367 AREAS OF SEMI-SQUARES IN IMPERIAL GALLONSCtafMMM*. Sides in Ins. 1 2 3 4 5 6 7 9 156 157 158 159 160 43.8844 44.4488 45.0168 45.5885 46.1637 43.9407 44.5055 45.0738 45.6458 46.2214 43.9970 44.5621 45.1309 45.7032 46.2792 44.0533 44.6188 45.1880 45.7607 46.3370 44.1097 44.6756 45.2451 45.8181 46.3948 44.1661 44.7324 45.3022 45.8757 46.4527 44.2226 44.7892 45.3594 45.9332 46.5106 44.2791 44.8461 45.4166 45.9908 46.5685 44 3356 44.9029 45.4739 46.0484 46.6265 44.3922 44.9599 45.5312 46.1060 46.6845 161 162 163 164 165 46.7426 47.325C 47.9111 48.5003 49.0940 46.8007 17.3835 47.9099 48.5599 19.153b 46.8588 47.4420 48.0287 48.6191 49.2131 46.9169 47.5005 48.0876 48.6784 49.2727 46.9751 47.5590 48.1435 48.7376 49.3324 47.0333 47.6176 48.2055 48.7969 49.3920 47.0916 47.6762 48.2645 48.8563 49.4517 47.1499 47.7349 48.3235 48.9157 49.5115 47.2082 47.7936 48.3825 48.9751 49.5713 47.2666 47.8523 48.4416 49.0345 49.6311 166 167 168 169 170 49.6909 50.2914 50.8955 51.5032 52.1145 19.7508 50.3517 50.9561 51.5642 52.1753 49.8107 50.4119 51.0168 51 .6252 52.2372 49.8707 50.4723 51.0774 51.6862 52.2986 49.9307 50.5323 51.1382 51.7478 52.3600 49.9907 50.5930 51.1989 51.8084 52.4215 50.0508 50.6534 51.2597 51.8696 52.4830 50.1109 50.7139 51.3205 51.9307 52.5446 50.1710 50.7744 51.3814 51.9920 52.6062 50.2312 50.8349 51.4423 51.0532 52.6678 171 172 173 174 175 52.7291 53.3480 53.9701 54.5958 55.2252 52.7911 53.4100 54.0325 54.0533 55.2883 52.8528 53.4721 54.0919 54.7214 55.3515 52.9146 ^3.5342 54.157-; 54 7842 55.4147 52.9764 53.5904 54.2199 54.8471 55.4779 53.0382 53.6586 54.2825 54.9100 55.5412 53.1001 53.7208 54.3451 54.9730 55.6045 53.1620 53.7831 54.4077 55.0360 55.6678 53.2240 53.8454 54.4704 55.0990 55.7312 53.2859 53.9077 54.5331 55.1621 55.7946 176 177 178 179 180 55.8581 56.4947 57.1348 57.7786 58.4260 55.9216 56.5585 57.1990 57.8432 58.4909 55.9851 56.6224 57.2633 57.9078 58.5559 56.0487 56.6863 57.3276 57.9724 53.6209 56.1123 56.7502 57.3919 58.0371 58.6859 56.1759 56.8143 57.4563 58.1018 53.7510 56.2396 56.8783 57.5206 58.1666 58.8161 56.3033 56.9424 57.5851 58.2314 58.8813 56.3671 57.0065 57.6495 58.2962 58.9465 56.4308 57.0706 57.7140 58.3611 59.0117 181 182 183 184 185 59.0769 59.7315 60.3397 61.0515 31.7169 59.1422 59.7972 80.4557 31.1179 61.7837 59.2076 59.8629 60.5218 31.1843 61.8504 59.2729 59.9286 60.5879 61.250S 61.9173 59.3383 59.9944 60.6540 61.3173 61.9841 59.4038 60.0602 60.7202 61.3838 62.0510 59.4693 60.1260 60.7864 61.4503 62.1179 59.5348 60.1919 60.8526 61.5169 62.1849 59.6003 60.2578 60.9189 61.5836 62.2519 59.6659 60.3237 C0.9852 61 .6502 62.3189 186 187 188 189 190 62.3859 33.0536 63.7318 64.4146 85.0931 62.4530 83.1230 63.8023 64.4328 65.1638 32.5202 63.1935 33.8705 84.5510 55.2352 62.5874 63.2611 63.9384 34.6193 65.3038 62.6546 63.3286 64.0063 64.6870 65.3724 62.7218 63.3962 64.0743 64.7559 65.4411 62.7891 63.4639 64.1423 64.8243 65.5099 62.8564 63.5315 64.2103 64.8927 65.5786 62.9238 63.5993 64.2784 64.9311 65.6474 62.9911 63.6670 64.3465 65.0296 35.7162 191 192 193 194 195 65.7851 66.4753 67.1700 C7.8679 68.5694 65.8540 86.5450 37.2396 67.9379 68.6397 65.9229 66.6143 67.3093 68.0079 68.7101 65.9919 66.6837 67.3790 68.0779 68.7805 66.060G 66.7530 67.4487 68.1480 68.8510 66.1300 66.8224 67.5185 68.2182 68.9214 66.1991 66.8919 67.5883 68.2883 68.9920 66.2682 66.9614 67.6581 68.3585 69.0625 66.3373 67.0309 67.7280 68.4288 69.1331 66.4065 67.1004 67.7979 68.4990 69.2038 196 197 198 199 200 69.2744 69.9831 70.6954 71.4113 72.1 80S 69.3451 70.0542 70.766S 71.4831 72.2030 69.4159 70.1253 70.8383 71.5549 72.2752 69.4867 70.1964 70.9098 71.6268 72.3474 69.5575 70.2676 70.9813 71.0987 72.4196 69.6283 70.3388 71.0529 71.7706 72.4919 69.6992 70.4101 71.1245 71.8426 72.5C43 69.7701 70.4813 71.1962 71.9146 72.6366 69.8411 70.5527 71.2678 71.9866 72.7090 69.9121 70.6240 71.3396 72.0587 72.7815 CHAPTER XXII. CONVERSION FACTORS. THE use of metric units on the continent of Europe for indus- trial and commercial purposes, their use in this country in chemical, metallurgical, and physical calculations, makes it often necessary to convert our customary English measures into metric units or vice versa. The following table, compiled by C. W. Hunt, is very useful in this regard: Millimeters X .03937 = inches. Millimeters -=- 25.4 = inches. Centimeters X .3937 = inches. Centimeters -*- 2.54 = inches. Meters X 39. 37= ins. (Act Congress). Meters X 3.281 = feet. Meters X 1 .094 = yards. Kilometers X -621 = miles. Kilometers -~ 1.6093 = miles. Kilometers X 3280.8693 = feet. Square millimetersX.00155 = sq. ins. Square millimeters ~- 645. l = sq. ins. Square centimeters X .155 = sq. inches. Square centimeters -f- 6. 451 =sq. ins. Square meters X 10.764 = square feet. Square kilometers X 247. 1 = acres. Hectare X 2.47 1 = acres. Cu. centimeters -f- 16. 383 = cu. inches. Cu. centimeters -r- 3.69 = fluid drams (U. S. P.). Cu. cent. -*- 29.57 = fl. oz. (U. S. P.). Cubic meters X 35.3 15 = cubic feet. Cubic meters X 1 .308= cubic yards. Cubic meters X 264.2 = gallons (231 cu. in.). LitersX61.022 = cu. in. (Act Cong.). Liters X 33.84 = fl. oz. (U. S. P.). Liters X, 2642 = gallons (231 cu. in.). Inters -h3.78= gallons (231 cu. in.). Li ters-f- 28.3 16= cubic feet. Hectoliters X 3,531 = cubic feet. Hectoliters X 2.84= bushels (2150.42 cu. in.). Hectoliters X . 131 = cubic yards. Hectoliters -r- 26.42 = gals. (231 cu. in.). Grammes XI 5. 432 = grains (Act Con- Grammes -f- 981 = dynes. Grammes (water)-r-29.57 = fl. ounces. Grammes -* 28.35 = ounces avoir. Grammes per cu. cent. -7-27.7 = Ibs. per cu. in. Joule X .7373 = foot-pounds. Kilogrammes X 2.2046 = pounds. Kilogrammes X 35.3 = ounces avoir. Kilogms. -=-907.2 = tons (2000 Ibs.). Kilogms. per sq. cent.X 14. 223 = Ibs. per square inch. Kilogram-meters X 7.233 = f t.-lbs. Kilogms. per meter X .672 = Ibs. per ft. Kilogms. per cu. meter X .062 = Ibs. per cubic foot. Kilogms. per chevalX 2.235 = Ibs. per horse-power. Kilowatts X 1.34= horse-power. Watts -r- 746 = horse-power. Watts X. 7373 = ft.-lbs. per second. Calorie X 3.968 =B.t.u. Cheval vapeur X .9863 = horse-power. (Centigrade XI. 8)+ 32 = deg. Fahr. Franc X . 193 = dollars. Gravity Paris =980.94 centimeters per second. 368 CONVERSION FACTORS. 369 One cubic meter. REDUCTION OF FRENCH AND ENGLISH MEASURES. f 39. 37043 inches Onemeter I 3.28087 feet ( 35. 314 cubic feet I 1 . 308 cubic yards One cubic yard . 7645 cubic meters One cubic foot 0.02832 cubic meters ^ u - i / 6 1.023 cubic inches One cubic decimeter { Q Q353 cubic ^ One cubic foot 28.32 cubic decimeters One cubic centimeter 0.061 cubic inches One cubic inch 16.387 cubic centimeters 61.023 cubic inches 0.03531 cubic feet 2. 1135 pints 1.0567 quarts (American) . 2642 gallons (American) 2 .202 pounds of water at 62 F. One cubic foot 28.317 liters One gallon (American, 231 cubic inches). . 3 . 785 liters One gallon (British, 277.274 cubic inches) . 4 . 543 liters One quart (57.75 cubic inches) 946.30 cubic centimeters One pint (28.875 cubic inches) 473.15 cubic centimeters One milligramme .015432 grains One grain 64 . 799 milligrammes One gramme 15 . 43235 grains One grain .064799 grammes One gramme .03215 ounces (troy) One ounce (troy, 480 grains) 31 . 10348 grammes One liter (0.001 cubic meter or one cubic decimeter). . . . Milligrammes to Grains. Grains to Milligrammes. Grammes to Grains. Grains to Grammes. Grammes to Ounces (Avoirdupois). 1 0.01543 64.7989 15.43235 0.064799 0.035274 2 0.03086 129.5978 30.86470 0.129598 0.070548 3 0.04630 194.3968 46.29705 0.194397 0.105822 4 0.06173 259.1957 61.72940 0.259196 0.141096 5 0.07716 323.9946 77.16175 0.323995 0.176370 6 0.09259 388.7935 92.59100 0.388794 0.211644 7 0.10803 453.5924 108.02645 0.453593 0.246918 8 0.12346 518.3914 123.45880 0.518392 0.282192 9 0.13889 583.1903 138.89115 0.583191 0.317466 10 0.15430 647.9890 154.32350 0.647990 0.352740 370 AMERICAN GAS-ENGINEERING PRACTICE. One gramme .035274 ounces (avoirdupois) One ounce (avoirdupois, 437.50 grains) J 28 . 35 grammes One kilogramme 2.2046 pounds (avoirdupois) One pound (avoirdupois, 7000 grains) . 45359 kilogrammes One pound (troy, 5760 grains). . . 0.37324 kilogrammes Ounces (Avoirdupois) to Grammes. Grammes to Ounces (Troy). Ounces (Troy) to Grammes. Kilogrammes to Pounds (Avoirdupois). Pounds (Avoirdupois) to Kilogrammes. 28.3495 0.03215 31 . 10348 2.20462 0.45359 56.6991 0.06430 62.20696 4.40924 0.90719 85.0486 0.09645 93.31044 6.61386 1.36078 113.3981 0.12860 124.41392 8.81849 1.81437 141.7476 0.16075 155.51740 11.02311 2.26796 170.0972 0.19290 186.62089 13.22773 2.72156 198.4467 0.22505 217.72437 15.43235 3.17515 226.7962 0.25721 248.82785 17.63697 3.62874 255.1457 0.28936 279.93133 19.84159 4.08233 283.4950 0.32150 311.03480 22.04620 4.53590 EQUIVALENTS OF WORK AND HEAT. 1 B.t.u. = 778 ft.-lbs. = 17.59 watts. 42.41 " = 33000 " =746 " = 1 H.P. In the French or metric system of units, a heat-unit or calorie is the quantity of heat required to raise 1 kilogramme of pure water 1 C. at or about 4 C. The following tabular statement shows the relation of the French and English units: FRENCH AND ENGLISH UNITS COMPARED. 1 calorie 3.968 B.t.u. 0.252 calorie 1 French mechanical equivalent, 425.0 kilogram- meters 3075 ft.-lbs. 107.7 kilogram-meters 1, or 778 ft.-lbs. For convenience in translating French and German results into English or American we have the following compound units: EQUIVALENT COMPOUND UNITS. 1 calorie per square meter . 369 B.t.u. per square foot 1 B.t.u. or 1 H.u. per square foot. . 2.713 calories per square meter 1 calorie per kilogramme 1 .800 H.u. per pound 1 H.u. per pound ' .556 calorie per kilogramme CONVERSION FACTORS. 371 CONVERSION OF HEAT-UNITS. Calories per Kilogramme to British Thermal Units per Pound. Calories per Cubic Meter to British Thermal Units per Cubic Foot. British Thermal Units per Pound to Calories per Kilogramme. British Thermal Units per Cubic Foot to Calories per Cubic Meter. 1 1.8 0.11236 0.556 8.898 ' 2 3.6 .22472 1.112 17.796 3 5.4 .33708 1.668 26.694 4 7.2 .44944 2.224 35.592 5 9.0 .56180 2.780 44.490 6 10.8 .67416 3.336 53.388 7 12.6 .78652 3.892 62 . 286 8 14.4 .89888 4.448 71.184 9 16.2 1.01124 5.004 80.082 10 18. 1 . 1236 5.560 88.980 15 27. 1.6854 8.340 133.470 20 36. 2.2472 11.120 177.960 25 45. 2.809 13.900 222.450 30 54. 3.3708 16.680 266.940 35 63. 3.9326 19.460 311.430 40 72. 4.4944 22.240 355.920 45 81. 5.0562 25.020 400.410 50 90. 5.618 27.800 444.900 55 99. 6.1798 30.580 489.390 60 108. 6.7416 33.360 533.880 65 117. 7.3034 36 . 140 578.370 70 126. 7.8652 38.920 622.860 75 135. 8.427 41.700 667.350 80 144. 8.9888 44.480 711.840 85 153. 9.5506 47.260 756.330 90 162. 10.1124 50.040 800.820 95 171. 10.6742 52.820 845.310 100 180. 11.236 55.600 889.800 200 360. 22.472 111.200 1779.600 300 540. 33.708 116.800 2669.400 44.944 222.400 359.200 400 720. 56.180 278. 4419. 500 900. 67.416 333.600 5339.200 600 1080. 78.652 389.200 6228.600 700 1260. 89.888 444.800 7118.400 800 1440. 101.124 500.400 8008.200 900 1620. 112.36 556. 8898. 1000 1800. 372 AMERICAN GAS-ENGINEERING PRACTICE. CONVERSION OF DEGREES CENTIGRADE AND FAHRENHEIT. In the centigrade thermometer the freezing-point of water is taken as 0, and on the Fahrenheit scale as 32. The boiling-point of water is taken as Iw0 0> onthe former and as 212 on the latter. This gives a range of 100 degrees between the freezing- and boil- ing-points of water on the centigrade scale, and of 180 degrees on the Fahrenheit scale, or a ratio of 1 to 1.8. Hence to change degrees centigrade to Fahrenheit, multiply the degrees centi- grade by 1.8 and add 32 to the product; and to change degrees Fahrenheit to centigrade, subtract 32 from the degrees Fahren- heit and multiply the remainder by the reciprocal of 1.8 or 0.556. In the following tables are tabulated for convenience of use the comparative values on the two scales. CONVERSION FACTORS. 373 CONVERSION OF THERMOMETRIC READINGS. Fahrenheit to Centigrade. F. c. F. ' C. F. C. F. C. -40 -40 1 -17.2 41 5. 81 27.2 -39 -39.4 2 -16.6 42 5.5 82 27.7 -38 -38.8 3 -16.1 43 6.1 83 28.3 -37 -38.3 4 -15.5 44 6.6 84 28.8 -36 -37.7 5 -15. 45 7.2 85 29.4 -35 -37.2 6 -14.4 46 7.7 86 30. -34 -36.6 7 -13.8 47 8.3 87 30.5 -33 -36.1 8 -13.3 48 8.8 88 31.1 -32 -35.5 9 -12.7 49 9.4 89 31.6 -31 -35. 10 -12.2 50 10. 90 32.2 -30 -34.4 11 -11.6 51 10.5 91 32.7 -29 -33.8 12 -11.1 52 11.1 92 33.3 -28 -33.3 13 -10.5 53 11.6 93 33.8 -27 -32.7 14 -10. 54 12.2 94 34.4 -26 -32.2 15 - 9.4 55 12.7 95 35. -25 -31.6 16 - 8.8 56 13.3 96 35.5 -24 -31.1 17 - 8.3 57 13.8 t 97 36.1 -23 -30.5 18 - 7.7 58 14.4 98 36.6 -22 -30. 19 - 7.2 59 15. 99 37.2 -21 -29.4 20 - 6.6 60 15.5 100 37.7 -20 -28.8 21 - 6.1 61 16.1 101 38.3 -19 -28.3 22 - 5.5 62 16.6 102 38.8 -18 -27.7 23 - 5. 63 17.2 103 39.4 -17 -27.2 24 - 4.4 64 17.7 104 40. -16 -26.6 25 - 3.8 65 18.3 105 40.5 -15 -26.1 26 - 3.3 66 18.8 106 41.1 -14 -25.5 27 - 2.7 67 19.4 107 41.6 -13 -25. 28 - 2.2 68 21.1 108 42.2 -12 -24.4 29 - 1.6 69 20. 109 42.7 -11 -23.8 30 - 1.1 70 20.5 110 43.3 -10 -23.3 31 - 0.5 71 21.6 111 43.8 - 9 -22.7 32 + 72 22.2 112 44.4 - 8 -22.2 33 + 0.5 73 22.7 113 45. - 7 -21.6 34 1.1 74 23.3 114 45.5 - 6 -21.1 35 1.6 75 23.8 115 46.1 - 5 -20.5 36 2.2 76 24.4 116 46.6 - 4 -20. 37 2.7 77 25. 117 47.2 - 3 -19.4 38 3.3 78 25.5 118 47.7 - 2 -18.8 39 3.8 79 26.1 119 48.3 - 1 -18.3 40 4.4 80 26.6 120 48.8 -17.7 374 AMERICAN GAS-ENGINEERING PRACTICE. CONVERSION OF THERMOMETRIC READINGS Continued. Fahrenheit to Centigrade. F. C. F. C. F. C. F. e. 121 49.4 161 71.6 201 93.8 241 116.1 122 50. 162 72.2 202 94.4 242 116.6 123 50.5 163 72.7 203 95. 243 117.2 124 51.1 164 73.3 204 95.5 244 117.7 125 51.6 165 73.8 205 96.1 245 118.3 126 52.2 166 74.4 206 96.6 246 118.8 127 52.7 167 75. 207 97.2 247 119.4 128 53.3 168 75.5 208 97.7 248 120. 129 53.8 169 76.1 209 98.3 249 120.5 130 54.4 170 76.6 210 98.8 250 121.1 131 55. 171 77.2 211 99.4 251 121.6 132 55.5 172 77.7 212 100. 252 122.2 133 56.1 173 78.3 213 100.5 253 122.7 134 56.6 174 78.8 214 101.1 254 123.3 135 57.2 175 79.4 215 101.6 255 123.8 136 57.7 176 80. 216 102.2 256 124.4 137 58.3 177 80.5 217 102.7 257 125. 138 58.8 178 81.1 218 103.3 258 125.5 139 59.4 179 81.6 219 103.8 259 126.1 140 60. 180 82.2 220 104.4 260 126.6 141 60.5 181 82.7 221 105. 261 127.2 142 61.1 182 83.3 222 105.5 262 127.7 143 61.6 183 83.8 223 106.1 263 128.3 144 62.2 184 84.4 224 106.6 264 128.8 145 62.7 185 85. 225 107.2 265 129.4 146 63.3 186 85.5 226 107.7 266 130. 147 63.8 187 86.1 227 108.3 267 130.5 148 64.4 188 86.6 228 108.8 268 131.1 149 65. 189 87.2 229 109.4 269 131.6 150 65.5 190 87.7 230 110. 270 132.2 151 66.1 191 88.3 231 110.5 271 132.7 152 66.6 192 88.8 232 111.1 272 133.3 153 67.2 193 89.4 233 111.6 273 133.8 154 67.7 194 90. 234 112.2 274 134.4 155 68.3 195 90.5 235 112.7 275 135. 156 68.8 196 91.1 236 113.3 276 135.5 157 69.4 197 91.6 237 113.8 277 136.1 158 70. 198 92.2 238 114.4 278 136.7 159 70.5 199 92.7 239 115. 279 137.2 160 71.1 200 93.3 240 115.5 CONVERSION FACTORS. 375 Inches X Inches X Inches X Square inches X Square inches X Cubic inches X Cubic inches X Cubic inches X Feet X Feet X Square feet X 144 Square feet X Cubic feet X 1728 Cubic feet X Cubic feet X 7 Yards X 36 Yards X 3 Yards X Square yards X 1296 Square yards X 9 Cubic yards X 46656 Cubic yards X 27 Miles X 63360 Miles X 5280 Miles X 1760 Avoir, oz. X Avoir, oz. X Avoir. Ibs. X 16 Avoir. Ibs. X Avoir. Ibs. X Avoir. Ibs. = 27 Avoir, tons X 32000 Avoir, tons X 2000 Watts X 746 Horse-power X USEFUL FACTORS. .08333 =feet .02778 = yards .00001578^miles .00695 = square feet .0007716 =square yards .00058 = cubic feet .0000214 = cubic yards .004329 =U.S. gallons .3334 = yards .00019 = miles .00 = square inches .1112 = square yards .00 = cubic inches .03704 = cubic yards .48 = U.S. gallons .000 = inches .000 =feet .0005681 = miles .000 = square inches .000 = square feet . 000 = cubic inches .000 = cubic feet .000 = inches .000 =feet .00 = yards .0625 = pounds .00003 125 = tons .000 = ounces . 00 1 = hundredweight .0005 =tons . 681 cu. inches of water at 39.2 F. .00 = ounces .00 = pounds . 00 = horse-power .00134 = watts Weight of round iron per foot= square of diameter in quarter inches -r- 6. Weight of flat iron per f oot = width X thickness X 10. 3. Weight of flat plates per square foot =5 pounds for each J inch thickness. Weight of chain = diameter squared X 10. 7 (approximately). Safe load (in pounds) for chains = square of quarter inches in diameter of bar. 376 AMERICAN GAS-ENGINEERING PRACTICE. WATER FACTORS. U. S. gallons X 8.33 -pounds U. S. gallons X . 13368 = cubic feet U. S. gallons > 2? 1 . 00 = cubic inches U. S. gallons X . 83 = English gallons U. S. gallons X 3 . 78 = liters English gallons (Imperial) X 10 = pounds English gallons (Imperial) X 0.16 = cubic feet English gallons (Imperial) X 277. 274 = cubic inches English gallons (Imperial) X 1.2 =U. S. gallons English gallons (Imperial) X 4 . 537 = liters Cubic feet (of water) (39.1) X 62.425 = pounds Cubic feet (of water) (39.1) X 7.48 =U. S. gallons Cubic feet (of water) (39.1) X 6.232 = English gallons Cubic feet (of water) (39.1) X 0.028 =tons Cubic foot of ice X 57.2 = pounds Cubic inches of water (39. 1) X . 036024 = pounds Cubic inches of water (39.1) X 0. 004329 =U. S. gallons Cubic inches of water (39.1) X 0.003607= English gallons Cubic inches of water (39. 1) X . 576384 = ounces Pounds of water X 27 . 72 = cubic inches Pounds of water X 0.01602 = cubic feet Pounds of water X 0.083 =U. S. gallons Pounds of water X . 10 = English gallons Tons of water X 268 . 80 = U. S. gallons Tons of water X 224 . 00 = English gallons Tons of water X 35.90 = cubic feet Ounces of water X 1 - 735 = cubic inches A column of water 1 inch square by 1 foot high weighs 0.434 pound, A column of water 1 inch square by 2.31 feet high weighs 1.000 pound. Water is at its greatest density at 39.2 F. Sea water is 1.6 to 1.9 heavier +han fresh. One cubic inch of water makes approximately 1 cubic foot of steam at atmospheric pressure. 27222 cubic feet of steam at atmospheric pressure weigh 1 pound. CHAPTER XXIII. PIPE AND MISCELLANEOUS DATA. THE formula generally used for calculating the capacity of a pipe for transmitting gas under low pressures not exceeding the head due to a few inches of water column is credited to Dr. Pole and is where Q=cu. ft. discharged at the exit end per hour; d= internal diameter, inches; h = pressure in inches of water column; 1= length of pipe in yards; g= specific gravity of the gas, air= 1. Prof. S. W. Robinson of Columbus, Ohio, has deduced the following formula for high pressures, which is slightly in excess of the observed results: y=48.4-= where 7 = cubic feet per hour at atmospheric pressure and TI; TI = absolute temperature of storage = 461 + reading F; T 2 = absolute temperature of gas flowing in pipe-line reading F; TQ = absolute temperature = 461 + 37 F. = 498 (at maxi- mum density of water) ; d 5 = diameter of pipe-line in inches; L = length of pipe-line in miles; p 1 = gage pressure at entrance end of gas-main, pounds per square inch; p 2 =gage pressure at exit end of main, pounds per square inch. 377 378 AMERICAN GAS-ENGINEERING PRACTICE. Some of the data found valuable in connection with pipe are given herewith in the following tables: WROUGHT-IRON WELDED PIPE. (1 in. diam. and below are butt-welded and tested to 300 Ibs. per sq. in. hydraulic pressure; 1| in. and above are lap-welded and tested to 500 Ibs. per sq. in. hydraulic pressure.) Inside Diameter. Outside Diameter. External Cir- cumference. Length of Pipe per Sq. Ft. of Outside Surface. Internal Area. External Area Length of Pipe containing 1 Cubic Foot. Weight per Foot of Length. No. of Threads per Inch per Screw. Contents in Gallons * per Foot. i! Inch. Inch. Inches. Feet. Inches. Inches. Feet. Lbs. Lbs. 0.40 1.272 9.440 0.012 0.129 2500.0 0.24 27 0.0006 0.005 0.54 1.696 7.075 0.049 0.229 1385.0 0.42 18 0.0026 0.021 0.67 2.121 5.657 0.110 0.358 751.5 0.56 18 0.0057 0.047 0.84 2.652 4.502 0.196 0.554 472.4 0.84 14 0.0102 0.085 j 1.05 3.299 3.637 0.441 0.866 270.0 1.12 14 0.0230 0.190 1 1.31 4.134 2.903 0.785 1.357 166.9 1.67 11} 0.0408 0.349 l\ 1.66 5.215 2.301 1.227 2.164 96.25 2.25 11} 0.0638 0.527 Ij 1.9 5.969 2.01 1.767 2.835 70.65 2.69 11} 0.0918 0.760 2 2.37 7.461 1.611 3.141 4.430 42.36 3.66 11} 0.1632 1.356 2\ 2.87 9.032 1.328 4.908 6.491 30.11 5.77 8 0.2550 2.116 3 3.5 10.996 1.091 7.068 9.621 19.49 7.54 8 0.3673 3.049 3^ 4. 12.566 0.955 9.621 12.566 14.56 9.05 8 0.4998 4.155 4 4.5 14.137 0.849 12.566 15.904 11.31 10.72 8 0.6528 5.405 4J 5. 15.708 0.765 15.904 19.635 9.03 12.49 8 0.8263 6.851 5 5.56 17.475 0.629 19.635 24.299 7.20 14.56 8 1.020 8.500 6 6.62 20.813 0.577 28.274 34.471 4.98 18.76 8 1.469 12.312 7 7.62 23.954 0.505 38.484 45.663 3.72 23.41 8 1.999 16.662 8 8.62 27.096 0.444 50.265 58.426 2.88 28.34 8 2.611 21.750 9 9.68 30.433 0.394 63.617 73.715 2.26 34.67 8 3.300 27.500 10 10.75 33.772 0.355 78.540 90.792 1.80 40.64 8 4.081 34.000 * The Standard U. S. gallon of 231 cubic inches. Equation of Pipes. It is frequently desired to know what number of pipes of a given size are equal in carrying capacity to one pipe of a larger size. At the same velocity of flow the volume delivered by two pipes of different sizes is proportional to the squares of their diameters; thus, one 4-inch pipe will deliver the same volume as four 2-inch pipes. With the same head, however, the velocity is less in the smaller pipe and the volume delivered varies about as the square root of the fifth power (i.e., as the 2.5 power). The following table has been calculated on this basis. The figures opposite the intersection of any two sizes is the number of the smaller-sized pipes required to equal one of the larger. Thus, one 4-inch pipe is equal to 5.7 2-inch pipes. PIPE AND MISCELLANEOUS DATA. 379 3 CO CO Oi CO 00 CO 'f OS CO rH rH r-i CrHlOCOI>COCOCOCO ' rH IO O rH rH (M Oi (M rH Tj< 00 rH CO OS CO Oi o CO CO OS CO 00 rH tO O CO O Tt< CO CO t>- OS rH CO OS I> tO CO 00 CO !> rH OS C^ rH r I C^ CO- CO CO (N CO IXN OS OS rH CO CO CO CO rH COtOl>-'OOOCO'OOOrHHHt>rHOOSOCOOO b-CO OS (N -, ^^ ^1 l"A * ift CO 81 380 AMERICAN GAS-ENGINEERING PRACTICE. PIPING AND PIPE-FITTINGS. The Crane Co. of Chicago, 111., have conducted tests on piping, and some of the conclusions were presented in a paper before the Engine Builders' Association at the spring meeting, 1902, by J. B. Berryman. The following is abstracted: Strength of Ordinary Commercial Pipe. Tests of lengths taken at random out of stock: 8-in. stood 2000 Ibs.; 10-in. 2300 Ibs.; 12-in. 1500 Ibs.; 16-in., } in. thick, 800 Ibs.; and 24-in., J in. thick, 600 Ibs. per sq. in. without rupture or distortion. Thou- sands of pieces of 20-in. size and under have stood 800 Ibs. per sq. in. Hence there is no reason why pipe heavier than standard should be used in power plants, except where water is bad and there may be corrosion. Flanged Joints. Most of our orders are for screwed or shrunk flanges in the ratio of 85 screwed to 15 shrunk. We prefer the screwed joint and use the following lengths of thread, those first given being for pressures up to 125 Ibs. and those in last column for pressure up to 250 Ibs. Diameter, Pipe. Thread Lengths. 4-in. 1A 1} 6-in. 1& 2 8-in. If 2& 12-in. 2^ 2& 16-in. 2^ 2J 20-in. 2| 3J Assuming a shearing strength of one-half tensile strength, the above proportions give a holding power fully three times ultimate strength of pipe. We have tested joints, starting with long threads on pipe, as per above table, and gradually cutting threads away. In no case were threads stripped, and results show that strength of joints was limited by strengths of the cast-iron flanges. On a 10-inch pipe threads were reduced until only 5 remained. Flanges broke at 650 pounds pressure, all threads remaining intact. A cal- culation of the amount of metal which would have to be sheared off before a joint parted will show that there is no likelihood of the threads stripping. Taking our standard length of thread, eight per inch, the results work out as follows: T ,, r Metal in Sectional Size. TH H Contact, Area of Full- Square Inches. weight Pipe. 8 1| 42 8.396 12 2^ 77 14.579 16f 2& 116 18.41 PIPE AND MISCELLANEOUS DATA. 381 Mess. Crane made a great number of tests on 8-in. pipe, using regular wrought-iron couplings to demonstrate that long threads are not necessary to strength. Final tests were made with barely 6 threads in contact, and f inch length of threaded part. The pipe was tested to 1000 pounds, the pressure being held a day without giving way. The only object in using long threads is to make a tight joint and not to gain strength. Pipe should be screwed clear through flange to guard against vibration and make a bearing for gasket on end of pipe and close thread against oxi- dizing action of steam. Screw flange on by power until pipe pro- jects TS in.; then face off end of pipe and face true with axis of pipe. In making shrunk joints the pipe is rounded up and calipered, flange bored out to a shrinking-fit size, brought to red heat, the pipe slipped in and peened over. Facing Flanges. Flanges are generally made with straight face finished smooth, straight face finished corrugated, male and female, tongue and groove and -h in. raised face inside bolt-holes. For pressure of 180 Ibs. or less our experiments show that a straight, concentrically corrugated face will hold a Rainbow or copper gasket. Have made repeated tests with pressures up to 1000 pounds without blowing out the gasket. Flanges. There are two recognized standards for flanges. One, for pressures up to 125 Ibs., was adopted by a joint committee of the A. S. M. E., the Master Steam Fitters' Association, and the manufacturers. The other, for pressures up to 20 Ibs., was adopted at a meeting of the manufacturers held in New York, June 28, 1901, and is generally referred to as the "Manufacturers 7 Standard." Flanged Fittings. We manufacture these in three weights for pressures up to 50, 125, and 250 Ibs. respectively. The thickness of the body metal of each is as follows: Diameter Pipe. Light. Standard. Extra Heavy. 6-in. & f 10-in. f if 12-in. I H 1 16-in. f 1 1& 20-in. ft l.i 1& 24-in. f 1J 1| These thicknesses give factors of safety of 10 or 12, when com- puted by the formula for pipes, which is desirable, since tests show that fittings burst at pressures less than indicated by theory. Valves. Valves are made of same thickness as the flanged fittings and designed for corresponding pressures. The standard 382 AMERICAN GAS-ENGINEERING PRACTICE. valves, 4-in. to 8-in., will burst at about 700 Ibs.; 10-in. to 16-in. at about 600 Ibs. The extra heavy valves, 4-in. to 8-in., burst at 1600 to 1900 Ibs.; 10-in. to 16-in. at about 1200 to 1500. A medium valve is also made for pressures between those for which the standard and extra-heavy valves are designed. In all these cases the valves were of the solid wedge type, and it was found that their disks would stand about 80 per cent, of the burst- ing pressure without leaking. It would not be possible to obtain equivalent results from parallel-seated double-disk valves, as their disks have comparatively light faces, set out by an internal wedg- ing mechanism, and will spring under pressure. It is not con- sidered desirable to rib the bodies of heavy valves owing to unequal strains. For high pressures use valves without outside screw and yoke. Pipe-bends. Unless of very short radius, they are generally made of standard pipe for pressures of 125 pounds or less, full- weight pipe up to 175 pounds, and extra-heavy pipe for higher pressures. WHITWORTH'S. SCREW-THREADS. GAS- AND WATER-PIPING. Diameter of Piping. Diameter Diameter of Piping. Diameter at No. of at No. of Bottom Threads Bottom Threads In- ternal. External. of Thread. per Inch. In- ternal. External. of Thread. per Inch. 0.3825 0.3367 28 11 2.245 2.1285 0.518 0.4506 19 2 2.347 2.2305 0.6563 0.5889 19 2\ 2.467 2.3505 0.8257 0.7342 14 2] 2.5875 2.4710 0.9022 0.8107 14 2\ 2.794 2.3775 1.041 0.9495 14 2i 3.0013 2.8848 1.189 1.0975 14 2| 3.124 3.0075 U" 1.309 1 . 1925 2| 3.247 3.1305 1.492 1.3755 25 3.367 3.2505 1.650 1.5335 3 3.485 3.3685 1.745 1.6285 11 31 3.6985 3.5820 1.8825 1.7660 si 3.912 3.7955 1 2.021 1.9045 sf 4.1255 4.0090 1' 2.047 1.9305 J 4 4.339 4.2225 PIPE AND MISCELLANEOUS DATA. 383 ijri r~ ^ II-HOOOOOOOOOOOOOOOOOOOOOOOOOOOOCX500 ill < i O O Oi O5 00 oooo< 1 o o fl ill 5*0 ' i oo i i co o i i i i i O iO 00 CO OQ 00 1-1 - O CO CO t^ !> CO CO r-l T-H (M < 1 -I Sf g e IM CO -I b- 00 CO CO t^rfii i't | co^icooocO'-t 00 t^ 00 CO 1 co c^j I s * o^ 3g Q OOOOi I"-*! ii ( o3 lal ^ rH i-l r-( (M > tfo . C g CO -f K3 00 |1^;S|3SS3 0) O ME 6- I* (M ^ t>rf5C^rfO rH rH i-t i I C<1 1 1 Tt< CO i-t 10CO r-l CO ^COt^ O i i(N i"^ ^O "^ CO CO CO *O O5iOOOr-(cOcOt^ PIPE AND MISCELLANEOUS DATA. 385 STANDARD WROUGHT-IRON AND STEEL-PIPE DIMENSIONS. (Pipes li in. diam. and smaller are butt welded; 1 in. diam. and larger are lap welded.) Size, Diam., Inches. Thickness of Wall, Inches. Area of Opening. Sq. Inches. Actual Outside Diameter, Inches. Nominal Weight per Foot, Lbs. Number of Threads per Inch of Screw. j . 0.068 0.0573 0.405 0.24 27 '. . 0.088 0.1041 0.54 0.42 18 l 0.091 0.1917 0.675 0.56 18 '. . 0.109 0.3048 0.84 0.84 14 \ 0.113 0.5333 1.05 1.12 14 1 0.134 0.8626 1.315 1.67 11* 11 0.140 1.496 1.66 2.24 H| 1* 0.145 2.038 1.9 2.68 n| 2 0.154 3.356 2.375 3.61 Hi zi 0.204 4.784 2.875 5.74 8 3 0.217 7.388 3.5 7.54 8 3i 0.226 9.887 4. 9. 8 0.237 12.73 4.5 10.66 8 4* 0.246 15.961 5. 12.49 8 5 0.259 19.99 5.563 14.5 8 6 0.28 28.888 6.625 18.76 8 7 0.301 38.738 7.625 23.27 8 8 0.322 50.04 8.625 28.18 8 9 0.344 62.73 9.625 33.7 8 10 0.366 78.839 10.75 40. 8 11 0.375 95.033 11.75 45. 8 12 0.375 113.098 12.75 49. 8 13 0.375 137.887 14. 54. 8 14 0.375 159.485 15. 58. 8 15 0.375 187.04 16. 62. 8 386 AMERICAN GAS-ENGINEERING PRACTICE. WEIGHT OF MALLEABLE-IRON FITTINGS FOR GAS-PIPE. Size, Inches. Lbs. per Hundred. Size, Inches. Lbs. per Hundred. Size, Inches. Lbs. per Hundred. ELBOWS, 90 DEGREES. SHORT FEMALE DROP ELBOWS. TEES. i 8 i 13 *xlx* 22 ixi 7* fxl 22 *xi Xi 20 i 8* f 19 *Xi Xf 24* m 14* 14 *xf 27 27 Ixi x* 26* 32* f 15 IX* 40* *xi 21 *xi Ixi 22* 19* 22 1 41* SHORT MALE AND FEMALE DROP ELBOWS. *xf ixi 26 29* fxf if! 31 35 33* ixf ixf 12 16* *> *> i xi Cl / 1 1 "xf 34* 75 29 ix* 47* f 26 -x* 35* ixi 45 LONG MALE AND FEMALE i XJ -xi 30* 1 42* DROP ELBOWS. ! Xj xi 50 ilxl 11X1 83 88* IX! 16 26 i X*Xr i x*xi 33 29 11 76 o \ XfXji 34 i*x| 102* SIDE OUTLET ELBOWS. i XlXJ 38 1*X1 94* 101 fxfxi 12 16 \ x*xi ixi 50* 29* 2X11 105 176 *x*xf 19* 2Q IX* 30* 34 2X1* 2 169 169* ixlxf ixix* 9 37 38 ixi 41 34 ELBOWS, 45 DEGREES. 8 121 ixixf 40 48 ixi* 64 69 116* ixix* 49* i x i X| 44* I v * 31 ixixl 51* } x x| 47* 1 49 1 55* IX -xi 54 11 83* 118 11 87 9U ixfxii ix*xf 67* 37* A 2 17O ix*x* 42 TEES. ix*x| 40* STREET ELBOWS. .J 9 ix*xi 48 f 16 iXl 8 ix*xii 68 I 26 ixi 9* ixi xf 39* IX* 44 12 IX: x* 44 47 ixf 16 1 X J X| 38 ix| 72 fxixi 15 IX: xi 49 1 73 , fxixf 18* ixi xil 67* iixi 107 fxi 16 i> 37 11 114 fxi 15 ixi 35 153 f 16* ix* 41* 1* 158 fx* 24 ixi 50* 2X1* 229 fxf 27 ] I 53 2 260 *xlxl . 18* iX 11 60* PIPE AND MISCELLANEOUS DATA. 387 WEIGHT OF MALLEABLE-IRON FITTINGS FOR GAS-PIPE Continued. Size, Inches. Lbs. per Hundred . Size, Inches. Lbs. per Hundred. Size, Inches. Lbs. per Hundred. TEES. TEES. MALE AND FEMALE DROP TEES. 1\ 1 i 1X1} xf xi xfxil x}xi x}xil xixi 109 83 89 83 94 67 79 2Xl}X2 2Xf 2X} 2X| 2X1 2X11 214 118 120 107 130 152 I XlXf ixixf fwith2}"l drop / MALE AND FE TENSION ] 44 37 25} MALE EX- >IECES. i xfxii i 89 2X1} o 154 1Q7 1 9* i xixf 56 \ r 15 l| XIX} 47 SIDE OUTLET TEES. , 22} I: xixi 65 32i ]_; xixi 74 1 28} a lj xixij 92 I 46 R. H. COUPLINGS. |j XIX} 109 1 56} i|xl 63 H 102 } *t 66 1 ; 7 iixi 71 FEMALE DROP TEES. ; 10} ] li ijxi H LlXl} x}xi 80 90 89 91 ixj ix] x| 15} 20} 21 1 11 17 25 40} 53 *1 1} i i X}X1} \/ 3 v/ 1 1 113} on i x j xl 16 21 $ 80 127 1^/\I /\ AJ 1}X!X1} i}xix| %/u 114 81 91 }xi xi fXi! 27 26} 16 33 R. & L. COUPLINGS. \- 9 i}xixil 94 !i s vl.v.1 31 | 13 i}xilxf 109 82 t /N * /N , x- 37} 35 17} 29 1} xitxi 91 1 xi 34 ] i 50} i} i} XllXll xilxi} 96 110 i xi xii 42 49} 1 1 I 72 106 1 Xf 1 vy 1 85 TTL ixi xf ^ 2 46 2 152 15 A$ 1 X| 1 XI liXH 77} 91} 102 102 ixixf ixix} ixixf 43 58 63 REDUCING C< IX} )UPLINGS. 6} 1}X2 126 131} MALE AND FEMALE DROP TEES. ixi ixi 9 7} 2X}X2 250 }> Cl 12 2X|X2 203 lx Xf 17 }Xf 14 2X1X2 221 f X ;Xf 14} ixi 21 2XHX11 172 i 18} Xf 21 2X11X1} 146 xi 181 i X} 22 2XHX2 203 }x 26 ixt 33 2Xl}XH 155 fx Xi 33 ixi 33 2Xl}Xl} 169 Ixi xi 36 IX} 36 388 AMERICAN GAS-ENGINEERING PRACTICE. WEIGHT OF MALLEABLE-IRON FITTINGS FOR GAS-PIFE^Continued. Size, Inches. Lbs. per Hundred. Size, Inches. Lbs. per Hundred. Size, Inches. Lbs. per Hundred. REDUCING COUPLINGS. CROSSES. CLOSE PATENT RETURN BENDS. 1X1 31 IX* 38* | 30* Uxt 54* 1 37* 1 88 HX* Hxl ifxi i*x* i*x| 53 47 53 68 69 ixfxi ixfxi ixlx* ixfxi 1X1 37 39 50* 54* 42 H 1* 2 OPEN PATENT BEN oo 152 228 333 " RETURN i*xi 59 IX* 32 * 35 ]i X 11 70 1 x I 37 I 104 2X| 85 1 59 4 1 134 2X* 90 Hxixi 73* 202* 2X| 102 Hxixi 83 1* w 2 251 2X1 125* 1- ' Xf 65 2 454 2XH 91 1 'X* 71* 2X1* 108* 1 tX* 86 i 3 1 92 | 5* CROSSES. H 100 8 I 7* i 13* 1*X 92 2 11* |Xi 16 fXf 85 1 19 ; 19* I] x * 87 11 27 *xfxi 22 li x| 108 4 34 23* xi 100 o 48i *xgx* 25 ii xu 121 CAPS. *Xi 13* i* 142 5* *xf 23* 2 x* 101 3 ** 2 8 29* 2X| 122 1 11* iXfX* 34* 2X1 118 3 2 19 1 x*xf 26 2.X 1J 162 1 30 |X*X* 36* 2X1* 149 40 32 2 218 li 70 2 97 DIMENSIONS OF FLANGE PIECES. "8 j. 3 . Q) o oT 1|| |fi |E| Ill ft. II 1 1 ' I o PQ II 1 -*-* Q P^ 13 o '^ o fa SO W 3 o O 3 O ^ 03 "o gw 2^ ^aj H o Q Q O J s i8 Ins. Ins. Ins. Ins. Ins. Im i. In s. Ins. Ins. Ins. 30 I 1| 37* 34* 20 1 . j 4 25 7 24 20 | 31 27 28* 24* 16 16 i 4 4 22 20 7 7 16 f | 22* 20 12 1 3 17 6 12 Z 18 15| 8 2* 14 5 10 1 | 16 13| 8 2* 12 4 8 A ! 13 Ml 8 2* 10 4 6 1 1 11 9* 4 2 8 3 4 1 f 9 91 4 i \ 2 6 2 4 A 7f 51 4 ] ; f 2 5 2 PIPE AND MISCELLANEOUS DATA. 389 WEIGHT AND THICKNESS OF LEAD PIPE. Caliber. Mark. Weight per Foot. Thickness. Mean Burst- ing Pressure. Safe Work- ing Pressure. In. Lb. Oz. In. Lbs. per Sq. In. Lbs. per Sq.In. f AAA 1 12 0.180 1968 492 AA 1 5 0.150 1627 406 A 1 2 0.130 1381 347 B 1 0.125 1342 335 1 C 14 0.110 1187 296 | 10 0.087 1085 271 & . . . 9i 0.080 775 193 AAA 3 0.250 1787 446 I .... 2 8 0.225 1655 413 I AA 2 0.180 1393 343 A 1 10 0.160 1285 321 B 1 3 0.125 980 245 C 1 0.100 782 195 D 9 0.065 468 117 10 0.070 556 139 12 0.090 625 156 , AAA 3 8 0.230 1548 387 AA 2 12 0.210 1380 345 , A 2 8 0.180 1152 288 B 2 0.160 987 246 i C 1 7 0.117 795 198 D 1 4 0.100 708 177 i AAA 4 14 0.290 1462 365 AA 3 8 0.225 * 1225 306 i A 3 0.190 1072 268 I B 2 3 0.150 865 216 C 1 12 0.125 782 195 | D 1 3 0.090 505 126 1 AAA 6 0.300 1230 307 1 AA 4 8 0.230 910 227 1 A 4 0.210 857 214 1 B 3 4 0.170 745 186 1 C 2 8 0.140 562 140 1 D 2 4 0.125 518 129 1 E 2 0.100 475 118 1 1 8 0.090 325 81 1 AAA 6 12 0.275 962 240 1 AA 5 12 0.250 823 205 1- A 4 11 0.210 685 171 1- B 3 11 0.170 546 136 390 AMERICAN GAS-ENGINEERING PRACTICE. WEIGHT AND THICKNESS OF LEAD PIPE Continued. Caliber. Mark. Weight per Foot. Thickness. Mean Burst- ing Pressure. Safe Work- ing Pressure. In. Lb. Oz. In. Lbs. per Sq. In. Lbs. per Sq. In. ii r C 3 0.135 420 105 i D 2 8 0.125 350 87 i* 2 0.095 322 80 1\ r AA 8 0.290 742 185 1< AA 7 0.250 700 175 ia A 6 4 0.220 628 157 li B 5 0.180 506 126 ; C 4 4 0.150 430 107 ; J D 3 8 0.140 315 78 I 3 0.120 245 61 a , B 5 116 I . C 4 93 \ , D 3 10 0.125 sis 79 2 AAA 10 11 0.300 611 152 2 AA 8 14 0.250 511 127 2 A 7 0.210 405 101 2 B 6 0.190 360 90 2 C 5 0.160 260 65 2 D 4 0.090 200 50 WEIGHTS OF STANDARD GAS-PIPE. Internal Diameter in Inches. Thickness of Shell in Inches. Weight per Foot in Pounds. Weight per Pipe in Pounds. Laid Length. 2 A 6 48 8 3 & 12| 150 12 4 1 17 204 12 5 ifa 24 288 12 6 A 30 360 12 8 1*5 40 480 12 10 A 50 600 12 12 | 70 840 12 14 16 84 1000 12 16 16 100 1200 12 18 H 134 1600 12 20 H 150 1800 12 24 1 184 2200 12 PIPE AND MISCELLANEOUS DATA. 391 APPROXIMATE SQUARE FEET OF RADIATING SURFACE OF PIPE PER LINEAL FOOT. (On all lehgths over one foot fractions less than tenths are added to or dropped.) f= Diameter of Pipe. r 1 l H H 2 2* 3 4 5 6 7 8 i .275 .346 .434 .494 .622 .753 .916 1 . 175 1.455 1.739 1.996 2.257 2 0.5 0.7 0.9 1. 1.2 1.5 1.8 2.4 2.9 3.5 4. 4.5 3 8 1 1.3 1.5 1.9 2.3 2.7 3.5 4.4 5.2 6 6 8 4 1.1 1.4 1.7 2. 2.5 3. 3.6 4.7 5.8 7. 8. 9. 5 1 4 1 7 2.2 2.4 3.1 3.8 4.6 5.8 7.3 7.7 10 11 3 6 1.6 2.1 2.6 2.9 3.7 4.5 5.5 7. 8.7 10.5 12. 13.5 7 1.9 2.4 3. 3.4 4.4 5.3 6.4 8.2 10.2 12.1 14. 15.8 8 2.2 2.8 3.5 3.9 5. 6. 7.3 9.4 11.6 13.9 16. 18. 9 2.5 3.1 3.9 4.4 5.6 6.8 8.2 10.6 13.1 15.7 18. 20.3 10 2.7 3.5 4.3 4.9 6.2 7.5 9.1 11.8 14.6 17.4 20. 22.6 11 3. 3.8 4.8 5.4 6.8 8.3 10. 12.9 16. 19.1 22. 24.9 12 3.3 4.1 5.2 5.9 7.5 9. 11. 14.1 17.4 20.9 24. 27.1 13 3.6 4.5 5.6 6.4 8.1 9.8 11.9 15.3 18.9 22.6 26. 29.4 14 3.8 4.8 6.1 6.9 8.7 10.5 12.8 16.5 20.3 24.3 28. 31.6 15 4.1 5.2 6.5 7.4 9.3 11.3 13.7 17.6 21.8 26.1 30. 33.9 16 4.4 5.5 6.9 7.9 10. 12., 14.6 18.8 23.2 27.8 32. 36.1 17 4.7 5.9 7.4 8.4 10.6 12.8 15.5 20. 24.7 29.5 34. 38.4 18 5. 6.2 7.8 8.9 11.2 13.5 16.5 21 .2 26.2 31.3 36. 40.6 19 5.2 6.6 8.3 9.4 11.8 14.3 17.4 22.3 27.6 33.1 38. 42.9 20 5.5 6.9 8.7 9.9 12.5 15. 18.3 23.5 29.1 34.8 40. 45.2 21 5.8 7.3 9.1 10.4 13. 15.8 19.2 24.7 30.5 36.5 42. 47.4 22 6. 7.6 9.6 10.9 13.7 16.5 20.2 25.9 32. 38.3 44. 49.7 23 6.3 8. 10. 11.3 14.3 17.3 21.1 27. 33.5 40. 46. 52. 24 6.6 8.3 10.4 11.9 14.9 18. 22. 28.2 34.9 41.7 48. 54.2 25 6.9 8.6 10.9 12.3 15.6 18.8 22.9 29.3 36.3 43.5 50. 56.4 26 7.1 9. 11.3 12.8 16.2 19.5 23.8 30.5 37.8 45.2 52. 58.6 27 7.4 9.4 11.7 13.3 16.8 20.3 24.7 31.7 39.3 47. 54. 61. 28 7.7 9.7 12.2 13.8 17.4 21. 25.6 32.9 40.7 48.7 56. 63.2 29 8. 10. 12.6 14.3 18. 21.8 26.6 34.1 42.2 50.4 58. 65.5 30 8.3 10.4 13. 14.8 18.7 22.5 27.5 35.3 43.6 52.1 60. 67.7 31 8.5 10.7 13.5 15.3 19.3 23.3 28.4 36.4 45.1 53.9 62. 70. 32 8.8 11.1 13.9 15.8 19.9 24.1 29.3 37.6 46.5 55.6 64. 72.2 33 9.1 11.4 14.3 16.3 20.5 24.8 30.2 38.8 48. 57.4 66. 74.4 34 9.4 11.7 14.7 16.8 21.2 25.6 31.1 40. 49.5 59.1 68. 76.7 35 9.6 12.1 15.2 17.3 21.8 26.3 32. 41.1 50.9 60.8 70. 79. 36 9.9 12.5 15.6 17.8 22.4 27. 33. 42.3 52.4 62.6 72. 81.3 37 10.2 12.8 16.1 18.3 23. 27.8 33.9 43.5 53.8 64.3 74. 83.5 38 10.5 13.2 16.5 18.8 23.7 28.5 34.8 44.6 55.2 66. 76. 85.8 39 10.7 13.5 16.9 19.3 24.3 29.3 35.7 45.8 56.7 67.8 78. 88. 40 11. 13.8 17.4 19.8 24.9 30.1 36.6 47. 58.2 69.5 80. 90.2 392 AMERICAN GAS-ENGINEERING PRACTICE. APPROXIMATE SQUARE FEET OF RADIATING SURFACE OF PIPE PER LINEAL FOOT Continued. fl* Diameter of Pipe. $* | l H 11 2 2i 3 4 5 6 7 8 41 11 3 14 ? 17.8 20.3 25.5 30.8 37.6 48.2 59.6 71.3 82. 92.5 42 11.5 14.5 18.2 20.8 26.1 31.6 38.5 49.4 61.1 73. 84. 94.8 43 11.8 14.9 18.7 21.3 26.8 32.3 39.4 50.6 62.5 74.8 86. 97. 44 12.1 15.2 19.1 21.8 27.4 33.1 40.3 51.7 64. 76.5 88. 99.3 45 12.4 15.6 19.5 22.2 28. 33.8 41.2 52.9 65.5 78.2 90. 101.6 46 12.7 15.9 20. 22.7 28.6 34.6 42.2 54. 67. 80. 92. 103.8 47 12.9 16.3 20.4 23.2 29.2 35.3 43. 55.2 68.4 81.7 94. 106. 48 13.2 16.6 20.8 23.7 29.9 36.1 43.9 56.4 69.8 83.5 96. 108.4 49 13.5 17. 21.3 24.2 30.5 36.8 44.8 57.6 71.2 85.1 98. 110.5 50 13.8 17.3 21.7 24.7 31.1 37.6 45.8 58.7 72.7 87. 100. 112.8 SINGLE-RIVETED LAP-JOINT WITH INSIDE COVER-PLATE. (1) Resistance to tearing between outer row of rivets = (Pd}tT. (2) Resistance to tearing between inner row of rivets and shearing outer row of rivets (P 2d)tT+ S. (3) Resistance to shearing three rivets j-S. (4) Resistance to crushing in front of three rivets = 3tdC. (5) Resistance to tearing at inner row of rivets and crushing in front of one rivet in outer row= (p2d)T + tdC. PIPE AND MISCELLANEOUS DATA. 393 DOUBLE-RIVETED LAP-JOINT WITH INSIDE COVER-PLATE. (1) Resistance to tearing at outer row of rivets = (Pd)tT. (2) Resistance to shearing four rivets = j-$. (3) Resistance to tearing at inner row and shearing outer row 7Q of rivets= (P-l^d)tT+~S. C (4) Resistance to crushing in front of four rivets = (5) Resistance to tearina; at inner row of rivets and crushing in front of one rivet =(P-lM)tT + tdC. Forms o-f Rivetirig 2 D - \60* & HL W//^,___j2Z6&. '- D 4\y\v\N A^^\^S\\H"D~- eD' ^> D^ C_7 * I.6D Hand Snap Machrne Countersunk Riyetirjcj Riv^t-incj. F?iveting. Riveting, 394 AMERICAN GAS-ENGINEERING PRACTICE. TENSILE STRENGTH OF PLATE PER ONE INCH OF WIDTH. Thickness . Tensile Strength per Square Inch. 50,000 55,000 60,000 65,000 70,000 .& 3125 3437 3750 4062 4375 i 6250 6875 . 7500 8125 8750 1 9375 10312 11250 12187 13125 7 12500 13750 15000 16250 17500 ft 15625 17187 18750 20312 21875 1 18750 20625 22500 24375 26250 A 21875 24062 26250 28437 30625 * 25000 27500 30000 32500 35000 1 28125. 30937 33750 36562 39375 ? 31250 34375 37500 40625 43750 tt 34375 37812 41250 44687 48125 1 37500 41250 45000 48750 52500 40625 44687 48750 52812 56875 I 43750 48125 52500 56875 61250 46875 51562 56250 60937 65625 50000 55000 60000 65000 70000 SHEARING STRENGTH OF RIVETS. (SINGLE SHEAR.) Shearing Strength per Square Inch. Diameter Area of _* Rivet. section. 30,000 35,000 40,000 45,000 50,000 t 0.1104 3312 3864 4416 4968 5520 0.1963 5889 6870 7852 8833 9815 | 0.3068 9204 10738 12272 13806 15340 | 0.4418 13254 15463 17672 19881 22090 0.6013 18039 21045 24052 27058 30065 1 0.7854 23562 27489 31416 35343 39270 PIPE AND MISCELLANEOUS DATA. 395 CRUSHING STRENGTH OF RIVETS. The crushing strength of rivets and plates, in joints that fail by crushing, is found by experiment to be high and irregular. In some cases it has amounted to 150,000 Ibs. per square inch; in a few tests it has been less than 85,000 Ibs. per square inch. A value of 95,000 Ibs. may be used with safety for general calculations. DOUBLE-RIVETED BUTT-JOINT. (1) Resistance to tearing at outer row of rivets = (P d)tT. (2) Resistance to shearing two rivets in double shear and one 57TG? 2 in single shear = j o. (3) Resistance to tearing at inner row of rivets and shearing one of the outer row of rivets= (P-2d')tT+^S, (4) Resistance to crushing in front of three rivets = 3tdC. (5) Crushing in front of two rivets and shearing one rivet TRIPLE-RIVETED BUTT-JOINT. (1) Resistance to tearing 'at outer row of rivets = (P d)tF. (2) Resistance to shearing four rivets in double shear and one . . . , 9rrd2 in single shear = ""T~~& (3) Resistance to tearing at middle row of rivets and shearing one rivet= (P 396 AMERICAN GAS-ENGINEERING PRACTICE. (4) Resistance to crushing in front of four rivets and shearing one rivet D (5) Resistance to crushing in front of five rivets dtC+dt" 13 2|" H" 7 j '22 P i /' 14 M;; 1|" 8 1" i '24 ft" j "16 H" 7 IA" No. 25 14 ft" ', "18 ft" H" 8 }< 25 16 A" \ "20 ft" 1|" 6 25 18 H" '12 M" H" 6 ^ft" 25 20 ft" ^ '14 H" if" 5 Jit" 26 14 A;; 1 '10 r If" 5 1 1?'' 26 16 '11 if" 4 ^A" 26 18 Q j '12 M" if" ^i ^H" 26 20 c '11 A" 2" 4 144" 28 14 u '12 ft" 2" 4| iii" 28 16 s I "10 M r/ USEFUL INFORMATION. Water. Doubling the diameter of a pipe increases its capacity four times. Friction of liquids in pipes increases as the square of the velocity. The mean pressure of the atmosphere is usually estimated at 14.7 Ibs. per square inch, so that with a perfect vacuum it will sustain a column of mercury 29.9 inches or a column of water 33.9 feet high at sea-level. To find the pressure in pounds per square inch of a column of water, multiply the height of the column in feet by .434. Approxi- mately, we say that every foot elevation is equal to J Ib. pressure per square inch; this allows for ordinary friction. To find the diameter of a pump cylinder to move a given quan- tity of water per minute (100 feet of piston being the standard of speed), divide the number of gallons by 4, then extract the square root, and the product will be the diameter in inches of the pump cylinder. To find the quantity of water elevated in one minute running at 100 feet of piston speed per minute, square the diameter of the water cylinder in inches and multiply by 4. Example : Capacity of a 5-inch cylinder is desired. The square of the diameter (5 inches) is 25, which, multiplied by 4, gives 100, the number of gallons per minute (approximately). 402 AMERICAN GAS-ENGINEERING PRACTICE. To find the horse-power necessary to elevate water to a given height, multiply the weight of the water elevated per minute in pounds by the height in feet, and divide the product by 33,000 (an allowance should be added for water friction, and a further allowance for loss in steam cylinder, say from 20 to 30 per cent.). The area of the steam piston, multiplied by the steam pressure, gives the total amount of pressure that can be exerted. The area of the water piston, multiplied by the pressure of water per square inch, gives the resistance. A margin must be made between the power and the resistance to move the pistons at the required speed say from 20 to 40 per cent., according to speed and other conditions. To find the capacity of a cylinder hi gallons: Multiplying the area hi inches by the length of stroke in inches will give the total number of cubic inches; divide this amount by 231 (which is the cubical contents of a U. S. gallon in inches), and the product is the capacity in gallons. WEIGHT AND CAPACITY OF DIFFERENT STANDARD GALLONS OF WATER. Cubic Inches in a Gallon. Weight of a Gallon in Pounds. Gallons in a Cubic Foot. Weight of a cubic foot of water, English Imperial or English . United States 277.274 231.0 10.00 8.33111 6.232102 7.480519 standard, 62.321 Ibs. avoirdupois Weight of crude petroleum, 6J Ibs. per U. S. gallon, 42 gal- lons to the barrel. Weight of refined petroleum, 6J Ibs. per U. S. gallon, 42 gal- lons to the barrel. A " miner's inch " of water is approximately equal to a supply of 12 U. S. gallons per minute. HANDY RULE FOR FINDING (APPROXIMATELY) THE CONTENTS OF A PIPE IN GALLONS AND CUBIC FEET. Rule. Multiply the square of the diameter of the pipe in inches by the length in yards, and divide by 10 for gallons and by 60 for cubic feet. Example. A pipe is 6 inches diameter and 400 yards long; what is the content? 6 2 X400-J- 10 = 1440 gallons. 62X400-^60 = 240 cubic feet. PIPE AND MISCELLANEOUS DATA. 403 CHEMICAL EQUATIONS FOR COMBUSTION IN OXYGEN. Hydrogen, H. 2H 2 +O 2 =2H 2 O. Relation by volume (2 vols.) + (1 vol.) = (2 vols.). " weight -1 + 8=9 Carbon monoxide, CO. 2CO+O 2 =2CO 2 . Relation by volume (2 vols.) + (1 vol.) = 2 vols. " weight 7 + 4 = 11 Olefiant gas, C 2 H 4 . C 2 H 4 +3O 2 =2CO 2 +2H 2 0. Relation by volume (1 vol.) + (3 vols.) = (2 vols.) + (2 vols.). " weight - 7 + 24 = 22 + 9 Marsh-gas, CH4. CH 4 +2O 2 =CO 2 +2H 2 O. Relation by volume - (1 vol.) + (2 vols.) = (1 vol.) + (2 vols.). " weight - 4 + 16 = 11 + 9 1 cu. ft. of hydrogen at 32 F. and 14.7 Ibs. per sq. in. = .00599 lb. To find the weight of any other gas per cubic foot, multiply half its molecular weight by .00599. CALORIFIC POWERS OF FUELS CALCULATED FROM ULTIMATE ANALYSIS. Dulong's formula: Heating value in B.t.u. = ^[14,600 C +62,000 (H- ~) +4050 SJ. Heating value in calories =y^ [8140 C +34,400 (H-^j +2250 S]. Mahler's formula: Heating value, calories = T ^ [8 140 C+34,500 H-3000(O+N)]. In the above C = carbon, H= hydrogen, 0= oxygen, N= nitro- gen, S= sulphur. 404 AMERICAN GAS-ENGINEERING PRACTICE. HEATS OF COMBUSTION OF VARIOUS SUBSTANCES IN OXYGEN. (Favre and Silberman.) One Part by Weight of Burning to Evolves Kilo-calories. B.t.u. Hydrogen H 2 at C H 2 A at 100 C C0 CO" CO 2 CO., and H O CO* and H,O 34462 28732 8080 2473 2403 13063 11858 62032 51717 14544 4451 4325 23513 21344 Carbon (wood charcoal) i ( Carbon monoxide Marsh-gas Olefiant gas . HEATS OF COMBUSTION OF GASES IN OXYGEN. (By Julius Thompsen.) Heat-units Products of Evolved. Kilo- Name. Sym- bol. at 18 C. (64.4 F.), Calories B.t.u. calories per B.t.u. cSbic Water Liquid. Kilo- per Pound Meter. Foot. of Gas. of Gas. Acetylene C,H, 2CO 2 + H 2 O 11917 21421 13881 1554 Benzine CH 6 6CO 2 + 2H 2 O 10102 18183 35300 3954 Carbonic oxide CO CO 2 2436 4385 3055 342 Ethane 2 H 6 :co 2 + 3H 2 o 12420 22356 16692 1870 Ethylene (olefiant gas) . Hydrogen ... .... A 2CO 2 + 2H 2 O H 2 O 11931 34180 21476 61524 14967 3062 1677 344 Methane (marsh-gas) . . CH, CO 2 + 2H 2 O 13320 23976 9548 1070 WEIGHT AND VOLUME OF GASES AND AIR REQUIRED IN COMBUSTION. Name. Weght per Cubic Foot in Pounds at 32 F. and 14.7 Pounds per Square Inch. Volume in Cubic Feet of 1 Pound of Gas at 14.7 Pounds per Square Inch. Cubic Feet Required to Burn 1 Cubic Foot of Gas. Pounds Re- quired to Burn 1 Pound of the Gas. Cubic Feet Formed of 32 F. 62 F. Oxy- gen. Air. Oxy- gen. Air. Steam. C0 2 1 1 2 Air 0.08073 0.12300 0.07830 0.00599 0.04470 0.07830 0.07830 0.08940 12.39 8.12 12.77 178.80 22.37 12.77 12.77 11.20 13.12 8.60 13.55 189.80 23.73 13.55 13.55 11.88 0.5 0.5 2.0 3.0 2.39 2.39 9.60 14.4 0.57 8.00 4.00 3.43 2.4B 34.8 17.4 14.9 1 2 2 Carbon dioxide . Carb. monoxide Hydrogen Marsh-gas Nitrogen .... Olefiant gas . . . Oxvsen . . Air = 20.92 per cent of oxygen. PIPE AND MISCELLANEOUS DATA. 405 1 Ib. carbon burning to CO 2 requires 11.6 Ibs. of air. 1 " " " " Co " 5.8 " li " Liquid hydrocarbons approximate 20,000 B.t.u. per Ib. Good coal approximates 14,000 B.t.u. per Ib. 2J Ibs. of dry wood=l Ib. of coal or .4 Ib. coal=l Ib. wood. SPECIFIC HEATS OF SUBSTANCES. SOLIDS AND LIQUIDS. Glass 1937 Coal. . 20 to 24 Cooper 0951 Cast iron 1298 Coke. . . . 0.203 Charcoal . . . 2410 Wrought iron 1138 Brickwork 1 /- nf \ Mercury . . . 0333 Steel soft 0.1165 TUT > . . .0.20 Masonry / Water 1 0000 Wood 0.46 to 0.65 PRESSURES, TEMPERATURE, AND VOLUME OF STEAM, FROM ATMOS- PHERIC PRESSURE TO 140 LBS. PER SQUARE INCH. Lbs. per Sq. In. Temperature. Volume. Lbs. per Sq. In. Temperature. Volume. At. pres. 212.8 1669 34 281.9 564 *1 216.2 1573 40 289.3 508 2 219.6 1488 45 295.5 470 3 222.7 1411 50 301.3 437 4 225.6 1343 55 306.4 408 5 228.5 1281 60 311.2 383 6 231.2 1225 65 315.8 362 7 233.8 1174 70 320.1 342 8 236.3 1127 75 324.3 325 9 238.7 1084 80 328.2 310 10 241.0 1044 85 332.0 295 12 245.5 973 90 335.8 282 14 249.6 911 95 339.2 271 16 253.6 857 100 342.7 259 18 257.3 810 105 345.8 251 20 260.9 767 110 349.1 240 22 264.3 729 115 352.1 233 24 267.5 569 120 355.0 224 26 270.6 664 125 357.9 218 28 273.6 635 130 360.6 210 30 276.4 610 135 363.4 205 32 279.2 586 140 366.0 198 * These are boiler pressures (above atmospheric), as shown by the steam-gage. The temperatures are Fahrenheit scale. The volumes given represent cubic inches of steam for every cubic inch of water evaporated. 406 AMERICAN GAS-ENGINEERING PHACTICE. FRENCH One milligramme (0.001 of a gramme) One centigramme (0.01 of a gramme) One decigramme (0. 1 of a gramme) One gramme (unit of weight) One decagramme (10 grammes) One hectogramme (100 grammes) One kilogramme (1000 grammes) One myriagramme (10,000 grammes) One quintal (100,000 grammes) One millier (1,000,000 grammes) 1016.0475443 kilogrammes 0.45359265 kilogramme 0.37324 kilogramme WEIGHTS. 0.0154 0.0000022 0.1543 0.0000220 1.5432 0.0002204 15.4323 0.0022046 154.3234 0.0220462 1543.2348 0.2204621 15432.3487 2.2046212 154323.487 22.0462124 1543234.87 220.462124 15432348.7 2204.62124 15680000.0 2204.0 7000.0 1.0 5760.0 1.0 grains avoirdupois Ibs. grains avoirdupois Ibs. grains avoirdupois Ibs. grains avoirdupois Ibs. grains avoirdupois Ibs. grains avoirdupois Ibs. grains avoirdupois Ibs. grains avoirdupois Ibs. grains avoirdupois Ibs. grains avoirdupois Ibs. grains avoirdupois Ibs. one long ton grains avoirdupois Ibs. grains troy pound TENSION OF MERCURY VAPOR. Degrees Centigrade. Tension in Millimeters. Degrees Centigrade. Tension in Millimeters. Degrees Centigrade. Tension in Millimeters. 100 0.75 180 11.00 260 96.73 110 1.07 190 14.84 270 123.01 120 1.53 200 19.90 280 155 . 17 130 2.18 210 26.35 290 194.46 140 3.06 220 34.70 300 242.15 150 4.27 230 45.35 310 299.69 160 5.90 240 58.82 320 368.73 170 8.09 250 75.75 330 450.91 FRENCH MEASURE. One millimeter (0.001 meter) .............. One centimeter (0.01 meter) One decimeter (0.1 meter) ................ One meter (unit of length) ................ One decameter (10 meters) ................ One hectometer (100 meters) ............. 3937 .043196 One kilometer (1000 meters) .............. 39370 . 431960 One myriameter (10,000 meters) ........... 393704.319600 or 6 miles, 376 yards, feet and 8^ inches 0.039370 inches . 393704 ' ' . 3 .937043 " 39 . 370432 " 393 . 704320 " PIPE AND MISCELLANEOUS DATA. 407 WHITWORTH'S STANDARD SCREW-THREADS FOR BOLTS, WITH SIZES OF HEXAGONAL NUTS AND BOLT-HEADS. Diameter of Bolt. Number of Threads per Inch. Diameter at Bottom of Thread. Distance Across Flats. Distance Across Corners. Thickness of Bolt- head. Thickness of Nut. Fractional Sizes. Decimal Sizes. Tif 0.0625 60 0.0411 0.212 0.2447 0.0547 TS & 0.09375 48 0.0670 0.280 0.3233 0.0820 & 0.125 40 0.0929 0.338 0.3902 0.1093 * JL 0.15625 32 0.1162 0.3875 0.4474 0.1367 :& 0.1875 24 0.1341 0.448 0.5173 0.1640 A | 0.25 20 0.1859 0.525 0.6062 0.2187 JL 0.3125 18 0.2413 0.6014 0.6944 0.2734 JL 3 0.375 16 0.2949 0.7094 0.8191 0.3281 | 0.4375 14 0.3460 0.8204 0.9473 0.3828 7 0.5 12 0.3932 0.9191 1.0612 0.4375 T & 0.5625 12 0.4557 1.011 1.1674 0.4921 & 1 0.625 11 0.5085 1.101 1.2713 0.5468 1 u 0.6875 11 0.5710 1.2011 1.3869 0.6015 ft ! 0.75 10 0.6219 1.3012 1.5024 0.6562 if 0.8125 10 0.6844 1.39 1.6050 0.7109 1 i 0.875 9 0.7327 1.4788 1.7075 0.7656 1 If 0.9375 9 0.7952 1.5745 1.8180 0.8203 if 1.0 8 0.8399 1.6701 1.9284 0.875 1 1.125 7 0.9420 1.8605 2 . 1483 0.9843 li if 1.25 7 1.0670 2.0483 2.3651 1.0937 if if 1.375 6 1.1615 2.2146 2.5571 1.2031 ii 1.5 6 1.2865 2.4134 2.7867 1.3125 i; if 1.625 5 1.3688 2.5763 2.9748 1.4218 if if 1.75 5 1.4938 2.7578 3 . 1844 1.5312 li ii 1.875 4.5 1.5904 3.0183 3.4852 1.6406 If 2 2.0 4.5 1.7154 3.1491 3.6362 1.75 2 2i 2.125 4.5 1.8404 3.337 3.8532 1.8593 2i 2f 2.25 4 1.9298 3.546 4.0945 1.9687 2* 2f 2.375 4 2.0548 3.75 4.3301 2.0781 2f 21 2.5 4 2 . 1798 3.894 4.4964 2.1875 21 2f 2.625 4 2.3048 4.049 4.6753 2.2968 2f 2| 2.75 3.5 2.3840 4.181 4.8278 2.4062 2| 2 2.875 3.5 2.5090 4.3456 5.0178 2.5156 2 3 3.0 3.5 2.6340 4.531 5.2319 2.625 3 H 3.125 3.5 2.7590 4.69 5.4155 2.734 3i 31 3.25 3.25 2.8559 4.85 5.6002 2.843 31 3f 3.375 3.25 2.9809 5.01 5.7850 2.953 3f 31 3.5 3.25 3.1059 5.157 5.9755 3.062 31 408 AMERICAN GAS-ENGINEERING PRACTICE. WHITWORTH'S STANDARD SCREW-THREADS FOR BOLTS, WITH SIZES OF HEXAGONAL NUTS AND BOLT-HEADS Continued. Diameter of Bolt. Number of Threads Diameter at Bottom Distance Across Distance Across Thickness of Bolt- Thickness Fractional Decimal per Inch. of Thread Flats. Corners. head. of Nut. Sizes. Sizes. 31 3.625 3.25 3.2309 5.362 6.1915 3.171 3J 3.75 3 3.3231 5.55 6.4085 3.281 3| 3.875 3 3.4481 5.75 6 . 6395 3.39 4.0 3 3.5731 5.95 6.8704 3.5 4 41 4.125 3 3.6981 6.162 7.1152 3.609 41 4J 4.25 2.875 3.8045 6.375 7.3612 3.718 41 4f 4.375 2.875 3.9295 6.6 7.6210 3.828 4f 8 4.5 2.875 4.0545 6.825 7.8819 3.937 41 if 4.625 2.875 4.1795 7 . 0625 8 . 1550 4.046 4f 4| 4.75 2.75 4.2843 7.3 8.4293 4.156 4f 41 4.875 2.75 4.4093 7.55 8.7179 4.265 41 5 5.0 2.75 4.5343 7.8 9.0066 4.375 5 51 5 . 125 2.75 4.6593 8.065 9.3126 4.484 51 5* 5.25 2.625 4.7621 8.35 9.6417 4.593 5j 5f 5.375 2.625 4.8871 8.6 9.9304 4.703 51 5 5.5 2.625 5.0121 8.85 10.2190 4.812 5i H 5.625 2.625 5.1371 9.15 10.5655 4.921 5f 5 5.75 2.5 5.2377 9.45 10.9119 5.031 51 5.875 2.5 5.3627 9.75 11.2583 5.140 51 6 6.0 2.5 5.4877 10.0 11.5470 5.25 6 The tables given below will be found useful in heat calcula- tions, and although not minutely accurate are sufficiently so for practical work. The British thermal unit (B.t.u.) is used, and the heat-energies given are calculated upon the assumption of 62 F. as the initial temperature, and the reduction of the temperature of the products of combustion to the same point as the standard for the computation of all heat-energies: Air by weight contains 23 parts O, 77 parts N. Air by volume contains 21 parts O, 79 parts N. Air consumed in combustion: 1 pound C burned to CO consumes 1.33 pounds O, with 4.46 N, making 5.79 air. 1 pound C burned to C0 2 consumes 2.667 pounds O, with 8.927 N, making 11.594 air. PIPE AND MISCELLANEOUS DATA. 409 Heat-units For 1 Lb. ' For 1 Cu. Ft. Developed in of Combustible, of Combustible, Burning. B.t.u. B.t.u. CtoCO 4,400 CtoCO 2 14,500 CO to CO 2 4,325 319 H to H 2 62,000 327 CH 4 to CO 2 and H 2 23,500 1007 C 2 H 4 to C0 2 and H 2 21,400 1593 Of course hydrogen is usually only burned to steam, and the energy in this case at 62 initial and 212 final temperature is 52,000 heat-units, or, making both temperatures 212, about 53,000 heat-units. Many writers use this standard for hydrogen in their computations; but in all theoretical calculations hydrogen should be given credit for the energy developed when the products of combustion are reduced to the standard temperature and the losses computed in its utilization from that standard. Number of cubic feet in one pound of the following gases at 62 F. and atmospheric pressure: Air 13 . 14 cubic feet per pound. N 13.50 " " " " 11.88 " " " H 189.70 " " " CO 13.55 " " " " CO 2 8.60 " " " CH 4 23.32 " " " C 2 H 4 13.46 " " " " Specific heat of hydrogen 3.4 " " tl all other gases may be taken at 0.25 The terms "heat-units " and " specific heat " are not well understood by many people, but the following definitions by a well-known authority will make them clear: Specific heat is that quantity of heat required to raise one pound of any substance one degree compared with that required to raise the temperature of an equal weight of water one degree. In other words, in writing down the specific heat of any substance we do it in comparison with water. That is to say, water is the unit or standard. If it takes three and four-tenths times as much heat to raise one pound of hydrogen one degree as to raise one pound of water one degree, we say the specific heat of hydrogen is 3.4. Now the same quantity of heat that will raise a pound of water one degree will raise about ten pounds of iron one degree, so we say the specific heat of iron is 0.10, or, to be exact, 0.1098. 410 AMERICAN GAS-ENGINEERING PRACTICE. Wood and Coal Fuel. The American Society of Mechanical Engineers in their rules for boiler tests allow 1 Ib. of wood = 0.4 Ib. of coal, or 2 Ibs. of wood=l Ib. of coal. Other authorities esti- mate 2 1 Ibs. of dry wood=l Ib. of good coal. One pound of any wood is practically equivalent to 1 Ib. of any other kind of wood equally dry. Lbs. Lbs. Coal. 1 cord of hickory or hard maple weighs 4500 = 2000 1 cord of white oak weighs 3850 = 1711 1 cord of beech, red oak, or black oak weighs 3250 = 1445 1 cord of poplar, chestnut, or elm weighs 2350 = 1044 1 cord of average pine weighs 2000 = 890 COMPARISON OF THERMOMETER SCALES. Centi- grade. Reau- mur. Fahren- heit. Centi- grade. Reau- mur. Fahren- heit. Centi- grade. Reau- mur. Fahren- heit. -30 -24.0 -22.0 14 11.2 57.2 58 46.4 136.4 -28 -22.4 -18.4 16 12.8 60.8 60 48.0 140.0 -26 -20.8 -14.8 18 14.4 64.4 62 49.6 143.6 -24 -19.2 -11.2 20 16.0 68.0 64 51.2 147.2 -22 -17.6 - 7.6 22 17.6 71.6 66 52.8 150.8 -20 -16.0 - 4.0 24 19.2 75.2 68 54.4 154.4 -18 -14.4 - 0.4 26 20.8 78.8 70 56.0 158.0 -16 -12.8 3.2 28 22.4 82.4 72 57.6 161.6 -14 -11.2 6.8 30 24.0 86.0 74 59.2 165.2 -12 - 9.6 10.4 32 25.6 89.6 76 60.8 168.8 -10 - 8.0 14.0 34 27.2 93.2 78 62.4 172.4 - 8 - 6.4 17.6 36 28.8 96.8 80 64.0 176.0 - 6 - 4.8 21.2 38 30.4 100.4 82 65.6 179.6 - 4 - 3.2 24.8 40 32.0 104.0 84 67.2 183.2 - 2 - 1.6 28.4 42 33.6 107.6 86 68.8 186.8 0,0 32.0 44 35.2 111.2 88 70.4 190.4 2 1.6 35.6 46 36.8 114.8 90 72.0 194.0 4 3.2 39.2 48 38.4 118.4 92 73.6 197.6 6 4.8 42.8 50 40.0 122.0 94 75.2 201.2 8 6.4 46.4 52 41.6 125.6 96 76.8 204.8 10 8.0 50.0 54 43.2 129.2 98 78.4 208.4 12 9.6 53.6 56 44.8 132.8 100 80.0 212.0 PIPE AND MISCELLANEOUS DATA. 411 MULTIPLIERS FOR FINDING THE EQUIVALENT RATE OF EVAPORATION OF WATER FROM AND AT 212 F., FOR GIVEN PRESSURES OF STEAM AND TEMPERATURES OF FEED-WATER. Temper- ature of Feed- water, Fahr. Boiler Pressures in Pounds per Square Inch above the Atmosphere. 5 10 15 20 25 30 32 1.187 1.192 1.195 1.199 1.201 1.204 1.206 35 1.184 1.189 .192 1.196 1.198 1.201 1.203 40 1.179 1.184 .187 1.191 1 . 193 1.196 1.198 45 1.173 1.178 .181 1.185 1.187 1 . 190 1.192 50 1.168 1.173 .177 1.180 1.182 1.185 1.187 55 1.163 1.168 .171 1.175 1.177 1.180 1.182 60 1.158 1.163 .166 1.170 1.172 1.175 1.177 65 1.153 1.158 1.161 1.165 1.167 1.170 1.172 70 1.148 1.153 1.156 1.160 1.162 1.165 1.167 75 1.143 1.148 1.151 1.155 1.157 1.160 1.162 80 1.137 1.143 .146 1.149 1.151 1.154 1.156 85 1.132 1.137 .140 1.144 1.146 1.149 1.151 90 1.127 1.132 .135 1.139 1.141 1.144 1.146 95 1.122 1.127 .130 1.134 1 . 136 1.139 1.141 100 1.117 1.122 .125 1.129 1.131 1.134 1.136 105 1.111 1.117 .120 1.123 1 . 125 1.128 1.130 110 1.106 1.111 .114 1.118 1.120 1.123 1.125 115 1.101 1.106 1.109 1.113 1.115 1.118 1.120 120 1.096 1.101 1.104 1.108 1.101 1.113 1.115 125 1.091 1.096 1.099 1.103 1.105 1.108 1.110 130 .085 1.091 1.094 1.097 1.099 1.102 1.104 135 .080 1.085 1.088 1.092 1.094 1.097 1.099 140 .075 1.080 1.083 1.087 1.089 1.092 1.094 145 .070 1.075 1.078 1.082 1.084 1.087 1.089 150 .065 1.070 1.073 1.077 1.079 1.082 1.084 155 .059 1.065 1.068 1.071 1.073 1.076 .078 160 .054 .059 .062 1.066 1.068 1.071 .073 165 1.049 .054 .057 1.061 1.063 1.066 .068 170 1.044 .049 .052 1.056 1.058 1.061 .063 175 1.039 .044 .047 1.051 1.053 1.056 .058 180 1.033 .039 .042 1.045 1.047 1.050 1.052 185 1.028 .033 .036 1.040 .042 1.045 1.047 190 1.023 .028 .031 1.035 .037 1.040 .042 195 1.018 .023 .025 1.030 .032 1.035 .037 200 1.013 1.018 .021 1.025 .027 1.030 .032 205 1.008 1.013 .015 1.020 .022 1.025 .027 210 1.008 1.008 .011 1.015 .017 1.020 .022 212 1.002 1.002 412 AMERICAN GAS-ENGINEERING PRACTICE. MULTIPLIERS FOR FINDING THE EQUIVALENT RATE OF EVAPORATION OF WATER FROM AND AT 212 F., FOR GIVEN PRESSURES OF STEAM AND TEMPERATURES OF FEED-WATER Continued. Temper- ature of Feed- Water, Fahr. Boiler Pressures in Pounds per Square Inch above the Atmosphere. 35 40 45 50 60 70 80 32 1.209 1.211 .212 .214 .217 .219 1.222 35 1.206 1.208 .209 .211 .214 .216 1.219 40 .201 1.203 .204 .206 .209 .211 1.214 45 .195 1.197 .198 .200 .203 .205 1.208 50 .190 1.192 .193 .195 .198 .200 1.203 55 .185 1.187 1.188 1.190 1.193 .195 1.198 60 .180 1.182 1.183 1.185 1.188 .190 1.193 65 1.175 1.177 1.178 1.180 1.183 1.185 1.188 70 1.170 .172 1.173 1.175 1.178 1.180 1.183 75 1.165 .167 1.168 1.170 1.173 1.175 1.178 80 1.159 .161 1.162 1.164 1.167 1.169 1.172 85 1.154 .156 1.157 1.159 1.162 1.164 1.167 90 1.149 .151 1.152 1.154 1.157 .159 1.162 95 1.144 .146 1.147 1.149 1.152 .154 1.157 100 1.139 .141 1.142 1.144 1.147 .149 1.152 105 1.133 .135 .136 1.138 1.141 .143 1.146 110 1.128 .130 .131 1.133 1.136 .138 1.141 115 1.123 .125 .126 1 . 128 1.131 .133 1.136 120 1.11-8 .120 .121 .123 .126 1.128 1.131 125 1.113 .115 .116 .118 .121 1.123 1.126 130 1.107 .109 .110 .112 .115 1.117 1.120 135 1.102 .104 .105 .107 .110 1.112 1.115 140 1.097 .099 .100 .102 .105 .107 1.110 145 .092 .094 .095 .097 .100 1.102 1.105 150 .078 .089 .090 .092 .095 1.097 1.100 155 .081 .083 .084 1.086 .089 1.091 1.094 160 .076 .078 .079 1.081 .084 1.086 1.089 165 1.071 .073 1.074 1.076 .079 1.081 1.084 170 1.066 .068 1.069 1.071 .074 1.076 1.079 175 1.061 1 063 1.064 1.066 .069 1.071 1.074 180 1.055 1 057 1.058 1.060 .063 1.065 1.068 185 1.050 1.052 1.053 1.055 .058 1.060 1.063 190 1.045 1.047 1.048 1.050 .053 1.055 1.058 195 1.040 1.042 1.043 1.045 .048 1.050 1.053 200 1.035 1.037 1.038 1.040 .043 1.045 1.048 205 1.030 1.032 1.033 1.035 1.038 1.040 1.043 210 1.025 1.027 1.028 1.030 1.033 1.035 1.038 PIPE AND MISCELLANEOUS DATA. 413 MULTIPLIERS FOR FINDING THE EQUIVALENT RATE OF EVAPORATION OF WATER FROM AND AT 212 F., FOR GIVEN PRESSURES OF STEAM AND TEMPERATURES OF FEED- WATER Continued. Temper- ature of Feed- water, Fahr. Boiler Pressures in Pounds per Square Inch above the Atmosphere. 90 100 120 140 160 180 200 32 1.224 1.227 1.231 1.234 1.237 1.239 1.241 35 1.221 1.224 1.228 1.231 1.234 1.236 1.238 40 1.216 1.219 1.223 1.226 1.229 1.231 1.233 45 1.210 1.213 1.217 1.220 1.223 1.225 1.227 50 1.205 1.208 1.212 1.215 1.218 1.220 1.222 55 1.200 1.203 .207 1.210 1.213 1.215 1.217 60 1.195 1.198 .202 1.205 1.208 1.210 1.212 65 1.190 1 . 193 .197 .200 1.203 1.205 1.207 70 1.185 .188 .192 .195 1.198 1.200 1.202 75 1.180 .183 .187 .190 1.193 1.195 1.197 80 1.174 .177 .181 .184 1.187 1.189 1.191 85 1.169 .172 .176 .179 1.182 1.184 1.186 90 1.164 .167 1.171 .174 1.177 1.179 1.181 95 1.159 .162 1.166 .169 1.172 1.174 1.176 100 1.154 1.157 1.161 .164 1.167 1.169 1.171 105 1.148 1.151 1.155 1.158 1.161 1.163 1.165 110 1.143 1.146 1.150 1.153 1 . 156 1.158 1.160 115 1.138 1.141 1.145 1.148 1.151 1.153 1.155 120 1.133 1.136 1.140 1.143 1.146 1.148 1.150 125 1.128 1.131 1.135 1.138 1.141 1.143 1.145 130 1.122 1.125 1.129 1 . 132 1.135 1.137 1.139 135 1.117 1.120 1.124 1.127 1.130 1.132 1.134 140 1.112 1.115 1.119 1.122 1.125 1.127 1.129 145 1.107 1.110 1.114 1.117 1.120 1.122 1.124 150 1.102 1.105 1.109 1.112 1.115 1.117 1.119 155 1.096 1.099 1 . 103 1.106 1.109 1.111 1.113 160 1.091 1.094 1.098 1.101 1.104 1.106 1.108 165 1.086 1.089 1.093 1.096 1.099 1.101 1.103 107 1.081 1.084 1.088 1.091 1.094 1.096 1.098 175 1.076 1.079 1.083 1.086 1.089 1.091 1.093 180 1.070 1.073 1.077 1.080 1.083 1.085 1.087 185 1.065 1.068 1.072 1.075 1.078 1.080 1.082 190 1.060 1.063 1.067 1.070 1.073 1.075 1.077 195 1.055 1.058 1.062 1.065 1.068 1.070 1.072 200 1.050 1.053 1.057 1.060 1.063 1.065 1.067 205 1.045 1.048 1.052 1.055 1.058 1.060 1.062 210 1.040 1.043 1.047 1.050 1.053 1.550 1.057 414 AMERICAN GAS-ENGINEERING PRACTICE. STANDARD SPECIFICATIONS FOR CAST-IRON PIPE AND SPECIAL CASTINGS. DESCRIPTION OF PIPES. SECTION 1. The pipes shall be made with hub and spigot joints, and shall accurately conform to the dimensions given in Tables Nos. 1 and 2. They shall be straight and shall be true circles in section, with their inner and outer surfaces concentric, and shall be of the specified dimensions in outside diameter. They shall be at least 12 feet in length, exclusive of socket. For pipes of each size from 4-inch to 24-inch, inclusive, there shall be two standards of outside diameter, and for pipes from 30-inch to 60-inch, inclusive, there shall be four standards of outside diam- eter, as shown by Table No. 2. All pipes having the same outside diameter shall have the same inside diameter at both ends. The inside diameter of the lighter pipes of each standard outside diameter shall be gradu- ally increased for a distance of about 6 inches from each end of the pipe so as to obtain the required standard thickness and weight for each size and class of pipe. Pipes whose standard thickness and weight are intermediate between the classes in Table No. 2 shall be made of the same outside diameter as the next heavier class. Pipes whose standard thickness and weight are less than shown by Table No. 2 shall be made of the same outside diameter as the Class A pipes, and pipes whose thickness and weight are more than shown by Table No. 2 shall be made of the same outside diameter as the Class D pipes. For pipes 4-inch to 12-inch, inclusive, one class of special castings shall be furnished, made from Class D pattern. Those having spigot ends shall have outside diameters of spigot ends midway between the two standards of outside diameter as shown by Table No. 2, and shall be tapered back for a distance of 6 inches. For pipes from 14-inch to 24-inch, inclusive, two classes of special castings shall be furnished, Class B special castings with Classes A and B pipes, and Class D special castings with Classes C and D pipes, the former to be stamped " AB" and the latter to be stamped "CD". For pipes 30-inch to 60-inch, inclusive, four classes of special castings shall be furnished, one for each class of pipe, and shall be stamped with the letter of the class to which they belong. PIPE AND MISCELLANEOUS DATA. 415 ALLOWABLE VARIATION IN DIAMETER OF PIPES AND SOCKETS. SECTION 2. Especial care shall be taken to have the sockets of the required size. The sockets and spigots will be tested by circular gages, and no pipe will be received which is defective in joint room from any cause. The diameters of the sockets and the outside diameters of the bead ends of the pipes shall not vary from the standard dimensions by more than *.06 of an inch for pipes 16 inches or less in diameter; .08 of an inch for 18-inch, 20-inch, and 24-inch pipes; .10 of an inch for 30-inch, 36-inch, and 42-inch pipes; .12 of an inch for 48-inch, and .15 of an inch for 54-inch and 60-inch pipes. ALLOWABLE VARIATION IN THICKNESS. SECTION 3. For pipes whose standard thickness is less than 1 inch the thickness of metal in the body of the pipe shall not be more than .08 of an inch less than the standard thickness, and for pipes whose standard thickness is 1 inch or more, the varia- tion shall not exceed .10 of an inch, except that for spaces not exceeding 8 inches in length in any direction, variations from the standard thickness of .02 of an inch in excess of the allowance above given shall be permitted. For special castings of standard patterns a variation of 50 per cent, greater than allowed for straight pipe shall be permitted. DEFECTIVE SPIGOTS MAY BE CUT. SECTION 4. Defective spigot ends on pipes 12 inches or more in diameter may be cut off in a lathe and a half-round wrought- iron band shrunk into a groove cut in the end of the pipe. Not more than 12 per cent, of the total number of accepted pipes of each size shall be cut and banded, and no pipe shall be banded which is less than 11 feet in length, exclusive of the socket. In case the length of a pipe differs from 12 feet, the standard weight of the pipe given in Table No. 2 shall be modified in accord- ance therewith. SPECIAL CASTINGS. SECTION 5. All special castings shall be made in accordance with the cuts and the dimensions given in the table forming a part of these specifications. The diameters of the sockets and the external diameters of 416 AMERICAN GAS-ENGINEERING PRACTICE. the bead ends of the special castings shall not vary from the stand- ard dimensions by more than .12 of an inch for castings 16 inches or less in diameter; .15 of an inch for 18-inch, 20-inch, and 24-inch; .20 of an inch for 30-inch, 36-inch, and 42-inch, and .24 of an inch for 48-inch, 54-inch, and 60-inch. These variations apply only to special castings made from standard patterns. The flanges on all manhole castings and manhole covers shall be faced true and smooth, and drilled to receive the bolts of the sizes given in the tables. The manufacturer shall furnish and deliver all bolts for bolting on the manhole covers, the bolts to be of the sizes shown on plans and made of the best quality of mild steel, with hexagonal heads and nuts and sound, well-fitting threads. MARKINGS. SECTION 6. Every pipe and special casting shall have distinctly cast upon it the initials of the maker's name. When cast espe- cially to order, each pipe and special casting larger than 4-inch may also have cast upon it figures showing the year in which it was cast and a number signifying the order in point of time in which it was cast, the figures denoting the year being above and the number below, thus: 1901 1901 1901 1 2 3 etc., also any initials, not exceeding four, which may be required by the purchaser. The letters and figures shall be cast on the outside and shall be not less than 2 inches in length and J of an inch in relief for pipes 8 inches in diameter and larger. For smaller sizes of pipes the letters may be 1 inch in length. The weight and the class letter shall be conspicuously painted in white on the inside of each pipe and special casting after the coating has become hard. ALLOWABLE PERCENTAGE OF VARIATION IN WEIGHT. SECTION 7. No pipe shall be accepted the weight of which shall be less than the standard weight by more than 5 per cent, for pipes 16 inches or less in diameter, and 4 per cent, for pipes more than 16 inches in diameter, and no excess above the standard weight of more than the given percentages for the several sizes shall be paid for. The total weight to be paid for shall not exceed for each size and class of pipe received the sum of the standard weights of the same number of pieces of the given size and class by more than 2 per cent. PIPE AND MISCELLANEOUS DATA. 417 No special casting shall be accepted the weight of which shall be less than the standard weight by more than 10 per cent, for pipes 12 inches or less in diameter, and 8 per cent, for larger sizes, except that curves, Y pieces, and breeches pipe may be 12 per cent, below the standard weight, and no excess above the standard weight of more than the above percentages for the several sizes will be paid for. These variations apply only to castings made from the standard patterns. QUALITY OF IRON. SECTION 8. All pipes and special castings shall be made of cast iron of good quality, and of such character as shall make the metal of the castings strong, tough, and of even grain, and soft enough to satisfactorily admit of drilling and cutting. The metal shall be made without any admixture of cinder iron or other inferior metal, and shall be remelted in a cupola or air- furnace. TESTS OF MATERIAL. SECTION 9. Specimen bars of the metal used, each being 26 inches long by 2 inches wide and 1 inch thick, shall be made without charge as often as the engineer may direct, and, in default of definite instructions, the contractor shall make and test at least one bar from each heat or run of metal. The bars, when placed flatwise upon supports 24 inches apart and loaded in the center, shall for pipes 12 inches or less in diameter support a load of 1900 pounds and show a deflection of not less than .30 of an inch before breaking, and for pipes of sizes larger than 12 inches shall support a load of 2000 pounds and show a deflection of not less than .32 of an inch. The contractor shall have the right to make and break three bars from each heat or run of metal, and the test shall be based upon the average results of the three bars. Should the dimensions of the bars differ from those above given, a proper allowance therefor shall be made in the results of the tests. CASTING OF PIPES. SECTION 10. The straight pipes shall be cast in dry sand molds in a vertical position. Pipes 16 inches or less in diameter shall be cast with the hub end up or down, as specified in the proposal. Pipes 18 inches or more in diameter shall be cast with the hub end down. 418 AMERICAN GAS-ENGINEERING PRACTICE The pipes shall not be stripped or taken from the pit while showing color of heat, but shall be left in the flasks for a sufficient length of time to prevent unequal contraction by subsequent exposure. QUALITY OP CASTINGS. SECTION 11. The pipes and special castings shall be smooth, free from scales, lumps, blisters, sand holes, and defects of every nature which unfit them for the use for which they are intended. No plugging or filling will be allowed. CLEANING AND INSPECTION. SECTION 12. All pipes and special castings shall be thoroughly cleaned and subjected to a careful hammer inspection. No cast- ing shall be coated unless entirely clean and free from rust, and approved in these respects by the engineer immediately before being dipped. COATING. SECTION 13. Every pipe and special casting shall be coated inside and out with coal-tar pitch varnish. The varnish shall be made from coal-tar. To this material sufficient oil shall be added to make a smooth coating, tough and tenacious when cold, and not brittle nor with any tendency to scale off. Each casting shall be heated to a temperature of 300 degrees Fahrenheit immediately before it is dipped, and shall possess less than this temperature at the time it is put in the vat. The ovens in which the pipes are heated shall be so arranged that all portions of the pipe shall be heated to an even temperature. Each casting shall remain in the bath at least five minutes. The varnish shall be heated to a temperature of 300 degrees Fahrenheit (or less if the engineer shall so order), and shall be maintained at this temperature during the time the casting is immersed. Fresh pitch and oil shall be added when necessary to keep the mixture at the proper consistency, and the vat shall be emptied of its contents and refilled with fresh pitch when deemed necessary by the engineer. After being coated the pipes shall be carefully drained of the surplus varnish. Any pipe or special casting that is to be recoated shall first be thoroughly scraped and cleaned. PIPE AND MISCELLANEOUS DATA. 419 HYDROSTATIC TEST. SECTION 14. When the coating has become hard, the straight pipes shall be subjected to a proof by hydrostatic pressure and, if required by the engineer, they shall also be subjected to a ham- mer test under this pressure. The pressures to which the different sizes and classes of pipes shall be subjected are as follows: 20-inch Diameter and Larger, Lbs. per Sq. In. Less than 20- inch Diameter Lbs. per Sq. In. Class A pipe 150 300 Class B pipe 200 300 Class C pipe 250 300 Class D pipe 300 300 WEIGHING. SECTION 15. The pipes and special castings shall be weighed for payment under the supervision of the engineer after the appli- cation of the coal-tar pitch varnish. If desired by the engineer, the pipes and special castings shall be weighed after their de- livery, and the weights so ascertained shall be used in the final settlement, provided such weighing is done by a legalized weigh- master. Bids shall be submitted and a final settlement made up on the basis of a ton of 2000 pounds. CONTRACTOR TO FURNISH MEN AND MATERIALS. SECTION 16. The contractor shall provide all tools, testing- machines, materials, and men necessary for the required testing, inspection, and weighing at the foundry of the pipes and special castings; and, should the purchaser have no inspector at the works, the contractor shall, if required by the engineer, furnish a sworn statement that all of the tests have been made as specified, this statement to contain the results of the tests upon the test- bars. POWER OF ENGINEER TO INSPECT. SECTION 17. The engineer shall be at liberty at all times to inspect the material at the foundry, and the molding, casting, 420 AMERICAN GAS-ENGINEERING PRACTICE. and coating of the pipes and special castings. The forms, sizes, uniformity, and conditions of all pipes and other castings herein referred to shall be subject to his inspection and approval, and he may reject, without proving, any pipe or other casting which is not in conformity with the specifications or drawings. INSPECTOR TO REPORT. SECTION 18. The inspector at the foundry shall report daily to the foundry office all pipes and special castings rejected, with the causes for rejection. CASTINGS TO BE DELIVERED SOUND AND PERFECT. SECTION 19. All the pipes and other castings must be delivered in all respects sound and conformable to these specifications. The inspection shall not relieve the contractor of any of his obli- gations in this respect, and any defective pipe or other castings which may have passed the engineer at the works or elsewhere shall be at all* times liable to rejection when discovered, until the final completion and adjustment of the contract; provided, how- ever, that the contractor shall not be held liable for pipes or special castings found to be cracked after they have been accepted at the agreed point of delivery. Care shall be taken in handling the pipes not to injure the coating, and no pipes or other mate- rial of any kind shall be placed in the pipes during transporta- tion or at any time after they receive the coating. DEFINITION OF THE WORD SECTION 20. Wherever the word " engineer" is used herein it shall be understood to refer to the engineer or inspector acting for the purchaser and to his properly authorized agents, limited by the particular duties intrusted to them. STANDARD PIPE SPECIALS. The following sections, dimensions, and weights of cast-iron pipe specials were adopted by the American Gaslight Association before it was merged into the American Gas Institute. They are the result of years of consideration and pretty well represent the average gas company requirements. PIPE AND MISCELLANEOUS DATA. 421 TABLE NO. 1. GENERAL DIMENSIONS OF PIPES. Nomi- nal Diam- eter, Inches. Classes. Actual Outside Diam- eter, Inches. Diameter of Sockets. Depth of Sockets. A B C Pipe, Inches. Special Castings, Inches. Pipe, Inches. Special Cast- ings, Inches. 4 A-B 4.80 5.60 5.70 3.50 4.00 1.5 1.30 0.65 4 C-D 5.00 5.80 5.70 3.50 4.00 1.5 1.30 0.65 6 A-B 6.90 7.70 7.80 3.50 4.00 1.5 1.40 0.70 6 C-D 7.10 7.90 7.80 3.50 4.00 1.5 1.40 0.70 8 9.05 9.85 10.00 4.00 4.00 1.5 1.50 0.75 8 'c-b' 9.30 10.10 10.00 4.00 4.00 1.5 1.50 0.75 10 A-B 11.10 11.90 12.10 4.00 4.00 1.5 1.50 0.75 10 C-D 11.40 12.20 12.10 4.00 4.00 1.5 1.60 0.80 12 A-B 13.20 14.00 14.20 4.00 4.00 1.5 1.60 0.80 12 C-D 13.50 14.30 14.20 4.00 4.00 1.5 1.70 0.85 14 A-B 15.30 16.10 16.10 4.00 4.00 1.5 1.70 0.85 14 C-D 15.65 16.45 16.45 4.00 4.00 1.5 1.80 0.90 16 A-B 17.40 18.40 18.40 4.00 4.00 1.75 1.80 0.90 16 C- 17.80 18.80 18.80 4.00 4.00 1.75 1.90 1.00 18 A-B 19.50 20.50 20.50 4.00 4.00 1.75 1.90 0.95 18 C-D 19.92 20.92 20.92 4.00 4.00 1.75 2.10 1.05 20 A-B 21.60 22.60 22.60 4.00 4.00 1.75 2.00 1.00 20 C-D 22.06 23.06 23.06 4.00 4.00 1.75 2.30 1.15 24 A-B 25.80 26.80 26.80 4.00 4.00' 2.00 2.10 1.05 24 C-D 26.32 27.32 27.32 4.00 4.00 2.00 2.50 1.25 30 A 31.74 32.74 32.74 4.50 4.50 2.00 2.30 1.15 30 B 32.00 33.00 33.00 4.50 4.50 2.00 2.30 1.15 30 C 32.40 33.40 33.40 4.50 4.50 2.00 2.60 1.32 30 D 32.74 33.74 33.74 4.50 4.50 2.00 3.00 1.50 422 AMERICAN GAS-ENGINEERING PRACTICE. TABLE NO. 1 Continued. Diameter of Depth of Nomi- Actual Sockets. Sockets. nal Outside Diam- Classes. Diam- A B C eter, Inches. eter, Inches. Pipe, Special Pipe, Special Cast- Inches. Castings, Inches. Inches. T in P' Inches. 36 A 37.96 38.96 38.96 4.50 4.50 2.00 2.50 .25 36 B 38.30 39.30 39.30 4.50 4.50 2.00 2.80 .40 36 C 38.70 39.70 39.70 4.50 4.50 2.00 3.10 .60 36 D 39.16 40.16 40.16 4.50 4.50 2.00 3.40 .80 42 A 44.20 45.20 45.20 5.00 5.00 2.00 2.80 .40 42 B 44.50 45.50 45.50 5.00 5.00 2.00 3.00 .50 42 C 45.10 46.10 46.10 5.00 5.00 2.00 3.40 .75 42 D 45.58 46.58 46.58 5.00 5.00 2.00 3.80 1.95 48 A 50.50 51.50 51.50 5.00 5.00 2.00 3.00 1.50 48 B 50.80 51.80 51.80 5.00 5.00 2.00 3.30 1.65 48 C 51.40 52.40 52.40 5.00 5.00 2.00 3.80 1.95 48 . D 51.98 52.98 52.98 5.00 5.00 2.00 4.20 2.20 54 A 56.66 57.66 57.66 5.50 5.50 2.25 3.20 1.60 54 B 57.10 58.10 58.10 5.50 5.50 2.25 3.60 1.80 54 C 57.80 58.80 58.80 5.50 5.50 2.25 4.00 2.15 54 D 58.40 59.40 59.40 5.50 5.50 2.25 4.40 2.45 60 A 62.80 63.80 63.80 5.50 5.50 2.25 3.40 1.70 60 . B 63.40 64.40 64.40 5.50 5.50 2.25 3.70 1.90 60 C 64.20 65.20 65.20 5.50 5.50 2.25 4.20 2.25 60 D 64.82 65.82 85.62 5.50 5.50 2.25 4.70 2.60 PIPE AND MISCELLANEOUS DATA. 423 TABLE NO. 2. STANDARD THICKNESSES AND WEIGHTS OF CAST-IRON PIPE. T J Class A, 100 Ft. Head, 43 Lbs. Pressure. Class B, 200 Ft. Head, 86 Lbs. Pressure. inside Diameter, Inches. Thick- Weight per Thick- Weight per Inches. Inches. Foot. Length. Foot. Length. 4 0.40 20.0 240 0.45 21.7 260 6 0.44 30.8 370 0.48 33.3 400 8 0.46 42.9 515 0.51 47.5 570 10 0.50 57.1 685 0.57 63.8 765 12 0.54 72.5 870 0.62 82.1 985 14 0.57 89.6 1075 0.66 102.5 1230 16 0.60 108.3 1300 0.70 125.0 1500 18 0.64 129.2 1550 0.75 150.0 1800 20 0.67 150.0 1800 0.80 175.0 2100 24 0.76 204.2 2450 0.89 233.3 2800 30 0.88 291.7 3500 1.03 333.3 4000 36 0.99 391.7 4700 1.15 454.2 545.0 42 1.10 512.5 6150 1.28 591.7 7100 48 1.26 666.7 8000 1.42 750.0 9000 54 1.35 800.0 9600 1.55 933.3 11200 60 1.39 916.7 11000 1.67 1104.2 13250 Class C, Class D, 300 Ft. Head, 130 Lbs. Pressure. 400 Ft. Head, 173 Lbs. Pressure. Inside Diameter, Inches. Thick- Weight per Thick- Weight per ness, Inches. n6ss, Inches. Foot. Length. Foot. Length. 4 0.48 23.3 280 0.52 25.0 300 6 0.51 35.8 430 0.55 38.3 460 8 0.56 52.1 625 0.60 55.8 670 10 0.62 70.8 850 0.68 76.7 920 12 0.68 91.7 1100 0.75 100.0 1200 14 0.74 116.7 1400 0.82 129.2 1550 16 0.80 143.8 1725 0.89 158.3 1900 18 0.87 175.0 2100 0.96 191.7 2300 20 0.92 208.3 2500 1.03 229.2 2750 24 1.04 279.2 3350 1.16 306.7 3680 30 1.20 400.0 4800 1.37 450.0 5400 36 1.36 545.8 6550 1.58 625.0 7500 42 1.54 716.7 8600 1.78 825.0 9900 48 1.71 908.3 10900 1.96 1050.0 12600 54 1.90 1141.7 13700 2.23 1341.7 16100 60 2.00 1341.7 16100 2.38 1583.3 19000 The above weights are for 12-feet laying lengths and standard sockets; proportionate allowance to be made for any variation therefrom. 424 AMERICAN GAS-ENGINEERING PRACTICE. TABLE NO. 3. ONE-QUARTER CURVES. (Dimensions in Inches.) Nominal Diameter. Class. T R K S 4 D 0.52 16 22.6 8 6 D 0.55 16 22.6 8 8 D 0.60 16 22.6 10 10 D 0.68 16 22.6 12 12 D 0.75 16 22.6 12 14 A-B 0.66 18 25.5 12 14 C-D 0.82 18 25.5 12 16 A-B 0.70 24 34. 12 16 C-D 0.89 24 34. 12 18 A-B 0.75 24 34. 12 18 C-D 0.96 24 34. 12 20 A-B 0.80 24 34. 12 20 C-D 1.03 24 34. 12 24 A-B 0.89 30 42.4 12 24 C-D 1.16 30 42.4 12 30 A 0.88 36 50.9 12 30 B 1.03 36 50.9 12 30 C 1.20 36 50.9 12 30 D 1.37 36 50.9 12 36 A 0.99 48 67.9 12 36 B 1.15 48 67.9 12 36 C 1.36 48 67.9 12 36 D 1.58 48 67.9 12 42 A 1.10 48 67.9 12 42 B 1.28 48 67.9 12 42 C 1.54 48 67.9 12 42 D 1.78 48 67.9 12 48 A 1.26 48 67.9 12 48 B .42 48 67.9 12 48 C .71 48 67.9 12 48 D .96 48 67.9 12 54 A .35 54 76.36 12 54 B .55 54 76.36 12 54 C .90 54 76.36 12 54 D .23 54 76.36 12 60 A .39 60 84.85 12 60 B .67 60 84.85 12 60 C 2.00 60 84.85 12 60 D 2.38 60 84.85 12 PIPE AND MISCELLANEOUS DATA. 425 TABLE NO. 4 ONE-EIGHTH AND ONE-SIXTEENTH CURVES. (Dimensions in Inches.) Nominal Diameter. Class. T One-eighth Curves. One-sixteenth Curves. R K s R K 4 D 0.52 24 18.4 4 48 18.7 6 D 0.55 24 18.4 4 48 18.7 8 D 0.60 24 18.4 4 48 18.7 10 D 0.68 24 18.4 4 48 18.7 12 D 0.75 24 18.4 4 48 18.7 14 A-B 0.66 36 27.6 72 28.1 14 O-D 0.82 36 27.6 72 28.1 16 A-B 0.70 36 27.6 72 28.1 16 C-D 0.89 36 27.6 72 28.1 18 A-B 0.75 36 27.6 72 28.1 18 C-D 0.96 36 27.6 72 28.1 20 A-B 0.80 48 36.7 96 37.5 20 C-D 1.03 48 36.7 96 37.5 24 A-B 0.89 60 45.9 120 46.8 24 C-D 1.16 60 45.9 120 46.8 30 A 0.88 60 45.9 120 46.8 30 B 1.03 60 45.9 120 46.8 30 C 1.20 60 45.9 120 46.8 30 D 1.37 60 45.9 120 46.8 36 A 0.99 90 68.9 180 70.2 36 B 1.15 90 68.9 180 70.2 36 C 1.36 90 68.9 180 70.2 36 D 1.58 90 68.9 180 70.2 42 A 1.10 90 68.9 180 70.2 42 B 1.28 90 68.9 180 70.2 42 C 1.54 90 68.9 180 70.2 42 D 1.78 90 68.9 180 70.2 48 A 1.26 90 68.9 180 70.2 48 B .42 90 68.9 180 70.2 48 C .71 90 68.9 180 70.2 48 D .96 90 68.9 180 70.2 54 A .35 90 68.9 180 70.2 54 B .55 90 68.9 180 70.2 54 C 1.90 90 68.9 180 70.2 54 D 2.23 90 68.9 180 70.2 60 A 1.39 90 68.9 180 70.2 60 B 1.67 90 68.9 180 70.2 60 C 2.00 90 68.9 180 70.2 60 D 2.38 90 68.9 180 70.2 426 AMERICAN GAS-ENGINEERING PRACTICE. TABLE NO. 5. ONE-THIRTY-SECOND AND ONE-SIXTY-FOURTH CURVES. (Dimensions in Inches.) Nominal Diameter. Class. T One-thi rt y-second Curves. One-sixty-fourth Curves. R K R K 20 A-B 0.80 240 47.05 480 47.10 20 C-D 1.03 240 47.05 480 47.10 24 A-B 0.89 240 47.05 480 47.10 24 C-D 1.16 240 47.05 480 47.10 30 A 0.88 240 47.05 480 47.10 30 B .03 240 47.05 480 47.10 30 C .20 240 47.05 480 47.10 30 D .37 240 47.05 480 47.10 36 A 0.99 240 47.05 480 47.10 36 B .15 240 47.05 480 47.10 36 C .36 240 47.05 480 47.10 36 D .58 240 47.05 480 47.10 42 A .10 240 47.05 480 47.10 42 B 1.28 240 47.05 480 47.10 42 C 1.54 240 47.05 480 47.10 42 D 1.78 240 47.05 480 47.10 48 A 1.26 240 47.05 480 47.10 48 B .42 240 47.05 480 47.10 48 C .71 240 47.05 480 47.10 48 D .96 240 47.05 480 47.10 54 A .35 240 47.05 480 47.10 54 B .55 240 47.05 480 47.10 54 C .90 240 47.05 480 47.10 54 D .23 240 47.05 480 47.10 60 A .39 240 47.05 480 47.10 60 B .67 240 47.05 480 47.10 60 C 2.00 240 47.05 480 47.10 60 D 2.38 240 47.05 480 47.10 PIPE AND MISCELLANEOUS DATA. 427 TABLE NO. 6. BRANCHES. (Dimensions in Inches.) Nominal Diam. A B c D E X F G Class. 4 4 11 23 11 D 6 4 12 24 12 D 6 6 12 24 12 D 8 4 13 25 13 D 8 6 13 25 13 D 8 8 13 25 13 D 10 4 14 26 14 D 10 6 14 26 14 D 10 8 14 26 14 D 10 10 14 26 14 D 12 4 15 27 15 D 12 6 15 27 15 D 12 8 15 27 15 D 12 10 15 27 15 D 12 14 12 4 15 16 27 28 15 16 1.25 1.62 2.50 D A-B 14 4 16 28 16 C-D 14 6 16 28 16 A-B 14 6 16 28 16 C-D 14 8 16 28 16 A-B 14 8 16 28 16 C-D 14 10 16 28 16 A-B 14 10 16 28 16 C-D 14 14 12 12 16 16 28 28 16 16 1.25 1.25 1.62 1.62 2.50 2.50 A-B C-D 428 AMERICAN GAS-ENGINEERING PRACTICE. TABLE NO. 6. BRANCHES (Continued). (Dimensions in Inches.) Nominal Diam. A B C D E X Y G Class. 14 14 16 14 14 4 16 16 17 28 28 29 16 16 17 1.25 1.25 1.62 1.62 2.50 2.50 A-B C-D A-B 16 4 17 29 17 C-D 16 6 17 29 17 A-B 16 6 17 29 17 C-D 16 6 17 29 17 A-B 16 6 17 29 17 C-D 16 8 17 29 17 A-B 16 8 17 29 17 C-D 16 10 17 29 17 A-B 16 10 17 29 17 C-D 16 16 16 16 16 16 18 12 12 14 14 16 16 4 17 17 17 17 17 17 18 29 29 29 29 29 29 30 17 17 17 17 17 17 18 1.25 1.25 1.25 1.25 1.25 1.25 1.62 1.62 1.62 1.62 1.62 1.62 2.50 2.50 2.50 2.50 2.50 2.50 A-B C-D A-B C-D A-B C-D A-B 18 4 18 30 18 C-D 18 6 18 30 18 A-B 18 6 18 30 18 C-D 18 8 18 30 18 A-B 18 8 18 30 18 C-D 18 10 18 30 18 A-B 18 10 18 30 18 C-D 18 18 18 18 18 18 18 18 20 20 12 12 14 14 16 16 18 18 6 6 18 18 18 18 18 18 18 18 19 19 30 30 30 30 30 30 30 30 31 31 18 18 18 18 18 18 18 18 19 19 1.25 1.25 1.25 1.25 1.25 1.25 1.25 1.25 1.25 1.62 1.62 1.62 1.62 1.62 1.62 1.62 1.62 1.62 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 A-B C-D A-B C-D A-B C-D A-B C-D A-B C-D 20 8 19 31 19 A-B 20 g 19 31 19 C-D 20 10 19 31 19 A-B 20 10 19 31 19 C-D 20 20 20 20 20 20 20 20 12 12 14 14 16 16 18 18 19 19 19 19 19 19 19 19 31 31 31 31 31 31 31 31 19 19 19 19 19 19 19 19 .25 .25 .25 .25 .25 .25 25 .25 .62 .62 .62 .62 .62 .62 .62 1.62 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 A-B C-D A-B C-D A-B C-D A-B C-D PIPE AND MISCELLANEOUS DATA. 429 TABLE NO. 6. BRANCHES (Continued). (Dimensions in Inches.) Nominal Diam. A B C D E X Y G Class. 20 20 19 31 19 1.25 1.62 2.50 A-B 20 20 19 31 19 1.25 1.62 2.50 C-D 24 6 21 33 21 A-B 24 6 21 33 21 C-D 24 8 21 33 21 A-B 24 8 21 33 21 C-D 24 10 21 33 21 A-B 24 10 21 33 21 C-D 24 12 21 33 21 1.25 1.62 2.50 A-B 24 12 21 33 21 1.25 .62 2.50 C-D 24 14 21 33 21 1.25 .62 2.50 A-B 24 14 21 33 21 .25 .62 2.50 C-D 24 16 21 33 21 .25 .62 2.50 A-B 24 16 21 33 21 .25 .62 2.50 C-D 24 18 21 33 21 .25 1.62 2.50 A-B 24 18 21 33 21 .25 1.62 2.50 C-D 24 20 21 33 21 .25 1.62 2.50 A-B 24 20 21 33 21 . .25 1.62 2.50 C-D 24 24 21 33 21 .25 .62 2.50 A-B 24 24 21 33 21 .25 .62 2.50 C-D 30 12 15 27 24 .25 .62 2.50 A 30 12 15 27 24 .25 .62 2.50 B 30 12 15 27 24 .25 .62 2.50 C 30 12 15 27 24 .25 .62 2.50 D 30 14 16 28 24 .25 .62 2.50 A 30 14 16 28 24 .25 .62 2.50 B 30 14 16 28 24 .25 .62 2.50 C 30 14 16 28 24 .25 1.62 2.50 D 30 16 17 29 24 1.25 1.62 2.50 A 30 16 17 29 24 1.25 1.62 2.50 B 30 16 17 29 24 1.25 1.62 2.50 C 30 16 17 29 24 .25 1.62 2.50 D 30 18 18 32 24 .25 1.62 2.50 A 30 18 18 32 24 .25 1.62 2.50 B 30 18 18 32 24 .25 1.62 2.50 C 30 18 18 32 24 .25 1.62 2.50 D 30 20 19 34 24 .25 1.62 2.50 A 30 20 19 34 24 .25 1.62 2.50 B 30 20 19 34 24 .25 1.62 2.50 C 30 20 19 34 24 .25 1.62 2.50 D 30 24 21 36 24 .25 1.62 2.50 A 30 24 21 36 24 .25 1.62 2.50 B 30 24 21 36 24 .25 1.62 2.50 C 30 24 21 36 24 .25 1.62 2.50 D 30 30 24 41 24 .50 2.00 3.00 A 30 30 24 41 24 .50 2.00 3.00 B 30 30 24 41 24 .50 2.00 3.00 C 30 30 24 41 24 .50 2.00 3.00 D 430 AMERICAN GAS-ENGINEERING PRACTICE. TABLE NO. 6. BRANCHES (Continued). (Dimensions in Inches.) Nominal Diam. A B C D E X Y G Class. 36 12 15 27 27 1.25 1.62 2.50 A 36 12 15 27 27 1.25 1.62 2.50 B 36 12 15 27 27 1.25 1.62 2.50 C 36 12 15 27 27 .25 1.62 2.50 D 36 . 14 16 28 27 .25 1.62 2.50 A 36 14 16 28 27 .25 1.62 2.50 B 36 14 16 28 27 .25 1.62 2.50 C 36 14 16 28 27 .25 1.62 2.50 D 36 16 17 29 27 .25 1.62 2.50 A 36 16 17 29 27 .25 .62 2.50 B 36 16 17 29 27 .25 .62 2.50 C 36 16 17 29 27 .25 .62 2.50 D 36 18 18 32 27 .25 .62 2.50 A 36 18 18 32 27 .25 .62 2.50 B 36 18 18 32 27 .25 .62 2.50 C 36 18 18 32 27 .25 .62 2.50 D 36 20 19 34 27 .25 .62 2.50 A 36 20 19 34 27 1.25 .62 2.50 B 36 20 19 34 27 1.25 .62 2.50 C 36 20 19 34 27 1.25 .62 2.50 D 36 24 21 36 27 1.25 .62 2.50 A 36 24 21 36 27 1.25 .62 2.50 B 36 24 21 36 27 1.25 1.62 2.50 C 36 24 21 36 27 1.25 1.62 2.50 D 36 30 24 41 27 1.50 2.00 3.00 A 36 30 24 41 27 1.50 2.00 3.00 B 36 30 24 41 27 1.50 2.00 3.00 C 36 30 24 41 27 1.50 2.00 3.00 D 36 36 27 44 27 1.50 2.00 3.00 A 36 36 27 44 27 1.50 2.00 3.00 B 36 36 27 44 27 1.50 2.00 3.00 C 36 36 27 44 27 1.50 2.00 3.00 D 42 12 15 27 30 1.25 1.62 2.50 A 42 12 15 27 30 1.25 1.62 2.50 B 42 12 15 27 30 1.25 1.62 2.50 C 42 12 15 27 30 1.25 1.62 2.50 D 42 14 16 28 30 1.25 1.62 2.50 A 42 14 16 28 30 1.25 .62 2.50 B 42 14 16 28 30 1.25 .62 2.50 C 42 14 16 28 30 1.25 .62 2.50 D 42 16 17 29 30 1.25 .62 2.50 A 42 16 17 29 30 1.25 .62 2.50 B 42 16 17 29 30 1.25 .62 2.50 C 42 16 17 29 30 1.25 .62 2.50 D 42 18 18 32 30 1.25 .62 2.50 A 42 18 18 32 30 1.25 .62 2.50 B 42 18 18 32 30 1.25 .62 2.50 C > 42 18 18 32 30 1.25 .62 2.50 D PIPE AND MISCELLANEOUS DATA. 431 TABLE NO. 6 BRANCHES (Continued). (Dimensions in Inches.) Nominal Diam. A B C D E X Y G Class. 42 20 19 34 30 1.25 1.62 2.50 A 42 20 19 34 30 1.25 1.62 2.50 B 42 20 19 34 30 1.25 1.62 2.50 C 42 20 19 34 30 1.25 1.62 2.50 D 42 24 21 36 30 1.25 1.62 2.50 A 42 24 21 36 30 1.25 1.62 2.50 B 42 24 21 36 30 1.25 1.62 2.50 C 42 24 21 36 30 1.25 1.62 2.50 D 42 30 24 41 30 1.50 2.00 3.00 A 42 30 24 41 30 1.50 2.00 3.00 B 42 30 24 41 30 1.50 2.00 3.00 C 42 30 24 41 30 1.50 2.00 3.00 D 42 36 27 44 30 1.50 2.00 3.00 A 42 36 27 44 30 1.50 2.00 3.00 B 42 36 27 44 30 1.50 2.00 3.00 C 42 36 27 44 30 1.50 2.00 3.00 D 42 , 42 30 47 30 1.50 2.00 3.00 A 42 , 42 30 47 30 1.50 2.00 3.00 B 42 42 30 47 30 1.50 2.00 3.00 C 42 42 30 47 30 1.50 2.00 3.00 D 48 16 17 29 33 1.25 1.62 2.50 A 48 16 17 29 33 1.25 1.62 2.50 B 48 16 17 29 33 1.25 1.62 2.50 C 48 16 17 29 33 1.25 1.62 2.50 D 48 18 18 32 33 1.25 1.62 2.50 A 48 18 18 32 33 1.25 1.62 2.50 B 48 18 18 32 33 1.25 1.62 2.50 C 48 18 18 32 33 .25 1.62 2.50 D 48 20 19 34 33 .25 1.62 2.50 A 48 20 19 34 33 .25 1.62 2.50 B 48 20 19 34 33 .25 1.62 2.50 C 48 20 19 34 33 .25 1.62 2.50 D 48 24 21 36 33 1.25 1.62 2.50 A 48 24 21 36 33 1.25 1.62 2.50 B 48 24 21 36 33 1.25 1.62 2.50 C 48 24 21 36 33 1.25 1.62 2.50 D 48 30 24 41 33 1.50 2.00 3.00 A 48 30 24 41 33 1.50 2.00 3.00 B 48 30 24 41 33 1.50 2.00 3.00 C 48 30 24 41 33 1.50 2.00 3.00 D 48 36 27 44 33 1.50 2.00 3.00 A 48 36 27 44 33 1.50 2.00 3.00 B 48 36 27 44 33 1.50 2.00 3.00 C 48 36 27 44 33 1.50 2.00 3.00 D 48 42 30 47 33 1.50 2.00 3.00 A 48 42 30 47 33 1.50 2.00 3.00 B 48 42 30 47 33 1.50 2.00 3.00 C 48 42 30 47 33 1.50 2.00 3.00 D 432 AMERICAN GAS-ENGINEERING PRACTICE. TABLE NO. 6 BRANCHES (Continued). (Dimensions in Inches.) Nominal Diam. A B C D E X Y G Class. 48 48 33 50 33 1.50 2.00 3.00 A 48 48 33 50 33 1.50 2.00 3.00 B 48 48 33 50 33 1.50 2.00 3.00 C 48 48 33 50 33 1.50 2.00 3.00 D 54 16 17 29 36 1.25 1.62 2.50 A 54 16 17 29 36 1.25 1.62 2.50 B 54 16 17 29 36 1.25 1.62 2.50 C 54 16 17 29 36 1.25 1.62 2.50 D 54 18 18 32 36 1.25 1.62 2.50 A 54 18 18 32 36 1.25 1.62 2.50 B 54 18 18 32 36 1.25 1.62 2.50 C 54 18 18 32 36 1.25 1.62 2.50 D 54 20 19 34 36 1.25 1.62 2.50 A 54 20 19 34 36 1.25 1.62 2.50 B 54 20 19 34 36 1.25 1.62 2.50 C 54 20 19 34 36 1.25 1.62 2.50 D 54 24 21 36 36 1.25 1.62 2.50 A 54 24 21 36 36 1.25 1.62 2.50 B 54 24 21 36 36 1.25 1.62 2.50 C 54 24 21 36 36 1.25 1.62 2.50 D 54 30 24 41 36 1.50 2.00 3.00 A 54 30 24 41 36 1.50 2.00 3.00 B 54 30 24 41 36 1.50 2.00 3.00 C 54 30 24 41 36 1.50 2.00 3.00 D 54 36 27 44 36 1.50 2.00 3.00 A 54 36 27 44 36 1.50 2.00 3.00 B 54 36 27 44 36 1.50 2.00 3.00 C 54 36 27 44 36 1.50 2.00 3.00 D 54 42 30 47 36 1.50 2.00 3.00 A 54 42 30 47 36 1.50 2.00 3.00 B 54 42 30 47 36 1.50 2.00 3.00 C 54 42 30 47 36 1.50 2.00 3.00 D 54 48 33 50 36 l.0 2.00 3.00 A 54 48 33 50 36 1.50 2.00 3.00 B 54 48 33 50 36 1.50 2.00 3.00 C 54 48 33 50 36 1.50 2.00 3.00 D 54 54 36 53 36 1.50 2.00 3.00 A 54 54 36 53 36 1.50 2.00 3.00 B 54 54 36 53 36 1.50 2.00 3.00 C 54 54 36 53 36 1.50 2.00 3.00 D 60 16 17 29 39 1.25 1.62 2.50 A 60 16 17 29 39 1.25 1.62 2.50 B 60 16 17 29 39 1.25 1.62 2.50 C 60 16 17 29 39 1.25 1.62 2.50 D 60 18 18 32 39 1.25 1.62 2.50 A 60 18 18 32 39 1.25 1.62 2.50 B 60 18 18 32 39 1.25 1.62 2.50 C 60 18 18 32 39 1.25 1.62 2.50 D PIPE AND MISCELLANEOUS DATA. 433 TABLE NO. 6 BRANCHES (Continued). (Dimensions in Inches.) Nominal Diam. A B C D E X Y G Class. 60 20 19 34 39 1.25 1.62 2.50 A 60 20 19 34 39 1.25 1.62 2.50 B 60 20 19 34 39 1.25 1.62 2.50 C 60 20 19 34 39 1.25 1.62 2.50 D 60 24 21 36 39 1.25 1.62 2.50 A 60 24 21 36 39 1.25 1.62 2.50 B 60 24 21 36 39 1.25 1.62 2.50 C 60 24 21 36 39 1.25 1.62 2.50 D 60 30 24 41 39 1.50 2.00 3.00 A 60 30 24 41 39 1.50 2.00 3.00 B 60 30 24 41 39 1.50 2.00 3.00 C 60 30 24 41 39 1.50 2.00 3.00 D 60 36 27 44 39 .50 2.00 3.00 A 60 36 27 44 39 .50 2.00 3.00 B 60 36 27 44 39 .50 2.00 3.00 C 60 36 27 44 39 .50 2.00 3.00 D 60 42 30 47 39 .50 2.00 3.00 A 60 42 30 47 39 .50 2.00 3.00 B 60 42 30 47 39 .50 2.00 3.00 C 60 42 30 47 39 .50 2.00 3.00 D 60 48 33 50 39 .50 2.00 3.00 A 60 48 33 50 39 .50 2.00 3.00 B 60 48 33 50 39 1.50 2.00 3.00 C 60 48 33 50 39 1.50 2.00 3.00 D 60 54 36 53 39 1.50 2.00 3.00 A 60 54 36 53 39 1.50 2.00 3.00 B 60 54 36 53 39 1.50 2.00 3.00 C 60 54 36 53 39 1.50 2.00 3.00 D 60 60 39 56 39 1.50 2.00 3.00 A 60 60 39 56 39 1.50 2.00 3.00 B 60 60 39 56 39 1.50 2.00 3.00 C 60 60 39 56 39 1.50 2.00 3.00 D 434 AMERICAN GAS-ENGINEERING PRACTICE. TYPE 1. 12" to 48". G=2.50" for 12" to 24" bells. X= 1.25" for 12" to 24" bells. F= 1.62" for 12" to 24" bells. Z= 1.00" for 12" to 14" bells. G=3.00" for 30" to 60" bells. X = 1.50" for 30" to 60" bells. Y = 2.00" for 30" to 60" bells. Z= 1.25" for 16" to 30" bells. Z=1.50" for 36" to 60" bells. TYPE 2. 4" to 16". TABLE NO. 7. Y BRANCHES. (Dimensions in Inches.) Nom.Diam. S P V W N R T! T 2 T 3 Type Class. E F 4 4 11.5 10.5 7 18 6.64 3.18 6 0.52 0.65 2 D 6 6 is!o 13.0 9.27 7.46 4.27 6 0.55 0.68 2 D 8 8 14.0 16.0 11.85 8.30 4.85 6 0.60 0.72 2 D 10 10 15.5 18.5 13.94 9.12 5.94 6 0.68 0.85 2 D 12 12 15.5 21.5 16.54 9.92 5.54 6 0.75 0.95 2 D 12 12 16.0 21.5 8.00 9.79 1.19 30 0.75 1.10 6.75 1 D 14 14 16.0 24.0 18.62 10.76 5.62 6 0.66 0.80 2 A-B 14 14 16.0 24.0 18.62 10.76 5.62 6 0.82 1.00 2 C-D 14 14 16.0 24.0 9.00 11.30 1.00 30 0.66 0.90 '6'.66 1 A-B 14 14 16.0 24.0 9 00 11.30 1.29 30 0.82 1.19 0.82 1 C-D PIPE AND MISCELLANEOUS DATA. 435 TABLE NO. 7. Y BRANCHES (Continued). (Dimensions in Inches.) Nom.Diam. . S P V W N R Ti T 2 T a Class. E F 16 16 17.5 27.5 21.70 11.60 6.70 6 0.70 0.85 A-B 16 16 17.5 27.5 21.70 11.60 6.70 6 0.89 1.10 C-D 16 16 17.0 27.5 10.50 13.00 1.10 30 0.70 1.00 o!70 A-B 16 16 17.0 27.5 10.50 13.00 1.50 30 0.89 1.30 0.89 C-D 18 18 18.0 30.0 12.0 14.7 1.17 30 0.75 1.08 0.75 A-B 18 18 18.0 30.0 12.0 14.7 1.36 30 0.96 1.40 0.96 C-D 20 20 18.0 34.0 13.5 16.4 1.25 30 0.80 1.15 0.80 A-B 20 20 18.0 34.0 13.5 16.4 1.62 30 1.03 1.50 1.03 C-D 24 18 9.0 30.0 12.0 14.7 1.17 30 0.89 1.08 0.75 A-B 24 18 9.0 30.0 12.0 14.7 1.36 30 1.16 1.40 0.96 C-D 24 20 12.0 34.0 13.5 16.4 1.25 30 0.89 .15 0.80 A-B 24 20 12.0 34.0 13.5 16.4 1.62 30 1.16 1.50 1.03 C-D 24 24 18.0 38.0 15.25 19.3 1.41 30 0.89 .30 0.89 A-B 24 24 18.0 38.0 15.25 19.3 1.84 30 1.16 .70 1.16 C-D 30 24 12.0 38.0 15.25 19.3 1.35 30 0.88 .25 0.89 A 30 24 12.0 38.0 15.25 19.3 1.35 30 1.03 .25 0.89 B 30 24 12.0 38.0 15.25 19.3 1.79 30 1.20 .65 1.16 C 30 24 12.0 38.0 15.25 19.3 1.79 30 1.37 .65 1.16 D 30 30 18 48 18 23.7 1.35 30 0.88 .25 0.88 A 30 30 18 48 18 23.7 1.62 30 1.03 .50 1.03 B 30 30 18 48 18 23.7 1.89 30 1.20 .75 1.20 C 30 30 18 48 18 23.7 2.16 30 1.37 2.00 1.37 D 36 30 10 48 18 23.7 1.35 30 0.99 1.25 0.88 A 36 30 10 48 18 23.7 1.62 30 1.15 1.50 1.03 B 36 30 10 48 18 23.7 1.89 30 .36 1.75 1.20 C 36 30 10 48 18 23.7 2.16 30 .58 2.00 1.37 D 36 36 18 54 21 28.2 1.62 24 .99 1.50 0.99 A 36 36 18 54 21 28.2 1.79 24 .15 1.65 1.15 B 36 36 18 54 21 28.2 2.16 24 .36 2.00 1.36 C 36 36 18 54 21 28.2 2.54 24 .58 2.35 1.58 D 42 30 6 48 18 23.7 1.35 30 .10 1.25 0.88 A 42 30 6 48 18 23.7 1.62 30 .28 1.50 1.03 B 42 30 6 48 18 23.7 1.89 30 .54 1.75 1.20 C 42 30 6 48 18 23.7 2.16 30 .78 2.00 1.37 D 42 36 10 54 21 28.2 1.62 24 .10 1.50 0.99 A 42 36 10 54 21 28.2 1.79 24 .28 1.65 1.15 B 42 36 10 54 21 28.2 2.16 24 .54 2.00 .36 C 42 36 10 54 21 28.2 2.54 24 .78 2.35 .58 D 42 42 18 60 25 33.1 1.79 24 .10 1.65 .10 A 42 42 18 60 25 33.1 1.95 24 .28 1.80 .28 B 42 42 18 60 25 33.1 2.44 24 .54 2.25 .54 C 42 42 18 60 25 33.1 2.87 24 .78 2.65 .78 D 48 36 2 54 21 28.2 1.62 24 .26 1.50 .99 A 48 36 2 54 21 28.2 1.79 24 .42 1.65 .15 B 48 36 2 54 21 28.2 2.16 24 .71 2.00 .36 C 48 36 2 54 21 28.2 2.54 24 .96 2.35 .58 D 436 AMERICAN GAS-ENGINEERING PRACTICE. TABLE NO. 7 (Continued). (Dimensions in Inches.) Nom.Diam s P F w N R T! T 2 T 3 Class. E F 48 42 10 60 25 33.1 1.79 24 1.26 1.65 1.10 A 48 42 10 60 25 33.1 1.95 24 1.42 1.80 1.28 B 48 42 10 60 25 33.1 2.44 24 1.71 2.25 1.54 C 48 42 10 60 25 33.1 2.87 24 1.96 2.65 1.78 D 48 48 18 68.5 28 37.6 1.95 24 1.26 1.80 1.26 A 48 48 18 68.5 28 37.6 2.27 24 1.42 2.10 1.42 B 48 48 18 68.5 28 37.6 2.76 24 1.71 2.55 1.71 C 48 48 18 68.5 28 37.6 3.13 24 1.96 2.90 1.96 D 54 36 2 54 21 28.2 1.62 24 1.35 1.50 0.99 A 54 36 2 54 21 28.2 1.79 24 1.55 1.65 .15 B 54 36 2 54 21 28.2 2.16 24 1.90 2.00 .36 C 54 36 2 54 21 28.2 2.54 24 2.23 2.35 .58 D 54 42 6 60 25 33.1 1.75 24 1.35 1.65 .10 A 54 42 6 60 25 33.1 1.95 24 1.55 1.80 .28 . B 54 42 6 60 25 33.1 2.44 24 1.90 2.25 .54 C 54 42 6 60 25 33.1 2.87 24 2.23 2.65 .78 D 54 48 10 68.5 28 37.6 1.95 24 1.35 1.80 .26 A 54 48 10 68.5 28 37.6 2.27 24 1.55 2.10 .42 B 54 48 10 68.5 28 37.6 2.76 24 1.90 2.55 .71 C 54 48 10 68.5 28 37.6 3.13 24 2.23 2.90 .96 D 54 54 18 78 31 42 2.16 24 1.35 2.00 .35 A 54 54 18 78 31 42 2.44 24 1.55 2.25 1.55 B 54 54 18 78 31 42 3.08 24 1.90 2.85 1.90 C 54 54 18 78 31 42 3.50 24 2.23 3.25 2.23 D 60 36 2 54 21 28.2 1.62 24 1.39 1.50 0.99 A 60 36 2 54 21 28.2 1.79 24 1.67 1.65 1.15 B 60 36 2 54 21 28.2 2.16 24 2.00 2.00 1.36 C 60 36 2 54 21 28.2 2.54 24 2.38 2.35 1.58 D 60 42 6 60 25 33.1 1.75 24 1.39 1.65 1.10 A 60 42 6 60 25 33.1 1.95 24 1.67 1.80 .28 B 60 42 6 60 25 33.1 2.44 24 2.00 2.25 .54 C 60 42 6 60 25 33.1 2.87 24 2.38 2.65 .78 D 60 48 8 68.5 28 37.6 1.95 24 1.39 1.80 .26 A 60 48 8 68.5 28 37.6 2.27 24 1.67 2.10 .42 B 60 48 8 68.5 28 37.6 2.76 24 2.00 2.55 1.71 C 60 48 8 68.5 28 37.6 3.13 24 2.38 2.90 1.96 D 60 54 12 78 31 42 2.16 24 1.39 2.00 1.35 A 60 54 12 78 31 42 2.44 24 1.67 2.25 1.55 B 60 54 12 78 31 42 3.08 24 2.00 2.85 1.90 C 60 54 12 78 31 42 3.50 24 2.38 3.25 2.23 D 60 60 18 90 35 46.7 2.22 24 1.39 2.05 1.39 A 60 60 18 90 35 46.7 2.70 24 1.67 2.50 1.67 B 60 60 18 90 35 46.7 3.25 24 2.00 3.00 2.00 C 60 60 18 90 35 46.7 3.78 24 2.38 3.50 2.38 D PIPE AND MISCELLANEOUS DATA. 437 TABLE NO. 8. BLOW-OFF BRANCHES. (Dimensions in Inches.) Norn. Diam. T T T y E F * 1 *2 8 4 12 7 0.60 52 D 10 4 12 8 0.68 0.52 D 10 6 12 8 0.68 0.55 D 12 4 12 10 0.75 0.52 D 12 6 12 10 75 55 D 14 4 12 11 66 52 A-B 14 4 12 11 82 52 C-D 14 6 12 11 66 55 A-B 14 6 12 11 82 55 C-D 16 4 12 12 70 52 A-B 16 4 12 12 89 52 C-D 16 6 12 12 70 0.55 A-B 16 6 12 12 0.89 0.55 C-D 18 4 12 13 75 52 A B 18 4 12 13 96 52 C-D 18 6 12 13 75 55 A-B 18 6 12 13 96 55 C-D 20 4 12 14 80 52 A-B 20 4 12 14 1 03 52 C-D 20 6 12 14 0.80 55 A-B 20 6 12 14 1.03 0.55 C-D 24 6 12 16 0.89 0.55 A-B 24 6 12 16 1 16 55 C-D 24 8 12 16 89 60 A-B 24 8 12 16 1 16 60 C-D 30 8 13 20 0.88 0.60 A 30 8 13 20 1.03 0.60 B 30 8 13 20 1 20 60 c 30 8 13 20 1 37 60 D 438 AMERICAN GAS-ENGINEERING PRACTICE. TABLE NO. 8 (Continued}. (Dimensions in Inches.) Nom. Diam. rrj /T? -\r E F L TI TZ A Class. 30 12 13 20 0.88 0.75 1.25 1.62 2.50 A 30 12 13 20 1.03 0.75 1.25 1.62 2.50 B 30 12 13 20 .20 0.75 1.25 1.62 2.50 C 30 12 13 20 .37 0.75 1.25 1.62 2.50 I) 36 8 13 23 .99 0.60 A 36 8 13 23 15 0.60 B Otl 36 8 13 23 .36 0.60 C 36 8 13 23 58 60 D 36 12 13 23 .99 0.75 .25 1.62 2.50 A 36 12 13 23 .15 0.75 .25 .62 2.50 B 36 12 13 23 .36 0.75 .25 .62 2.50 C 36 12 13 23 .58 0.75 .25 .62 2.50 D 42 12 15 26 .10 0.75 .25 .62 2.50 A 42 12 15 26 .28 0.75 .25 .62 2.50 B 42 12 15 26 .54 0.75 .25 .62 2.50 C 42 12 15 26 .78 0.75 .25 .62 2.50 D 42 16 15 26 .10 0.70 .25 .62 2.50 A 42 16 15 26 .28 0.70 .25 .62 2.50 B 42 16 15 26 .54 0.89 .25 .62 2.50 C 42 16 15 26 .78 0.89 .25 .62 2.50 D 48 12 17 30 .26 0.75 .25 .62 2.50 A 48 12 17 30 .42 0.75 .25 .62 2.50 B 48 12 17 30 .71 0.75 .25 .62 2.50 C 48 12 17 30 .96 0.75 .25 .62 2.50 D 48 16 17 30 .26 0.70 .25 .62 2.50 A 48 16 17 30 1.42 0.70 .25 .62 2.50 B 48 16 17 30 1.71 0.89 .25 .62 2.50 C 48 16 17 30 1.96 0.89 .25 .62 2.50 D 54 12 19 33 1.35 0.75 .25 .62 2.50 A 54 12 19 33 1.55 0.75 1.25 .62 2.50 B 54 12 19 33 1.90 0.75 1.25 .62 2.50 C 54 12 19 33 2.23 0.75 1.25 .62 2.50 D 54 16 19 33 1.35 0.70 1.25 .62 2.50 A 54 16 19 33 1.55 0.70 1.25 .62 2.50 B 54 16 19 33 1 .90 0.89 1.25 .62 2.50 C 54 16 19 33 2 23 0.89 1.25 .62 2.50 D 60 12 21 36 1.39 0.75 1.25 .62 2.50 A 60 12 21 36 1.67 0.75 1.25 .62 2.50 B 60 12 21 36 2.00 0.75 1 .25 1.62 2.50 C 60 12 21 36 2.38 0.75 .25 1.62 2.50 D 60 16 21 36 1.39 0.70 .25 1.62 2.50 A 60 16 21 36 1.67 0.70 .25 1.62 2.50 B 60 16 21 36 2.00 0.89 .25 1.62 2.50 C 60 16 21 36 2.38 0.89 .25 1.62 2.50 D PIPE AND MISCELLANEOUS DATA. ?X 2.0- *k BOUTS 439 TABLE NO. 9. BLOW-OFF BRANCHES WITH MANHOLES. (Dimensions in Inches.) Nominal Diameter. T P N T T Plaaa E F JL/ i \ * 2 i^iass. 30 8 17 20 21 0.88 0.60 A 30 8 17 20 21 1.03 0.60 B 30 8 17 20 21 1.20 0.60 C 30 8 17 20 21 1.37 0.60 D 30 12 17 20 21 0.88 0.75 A 30 12 17 20 21 1.03 0.75 B 30 12 17 20 21 1.20 0.75 C 30 12 17 20 21 1.37 0.75 D 36 8 17 23 24 0.99 0.60 A 36 8 17 23 24 .15 0.60 B 36 8 17 23 24 .36 0.60 C 36 8 17 23 24 .58 0.60 D 36 12 17 23 24 0.99 0.75 A 36 12 17 23 24 .15 0.75 B 36 12 17 23 24 .36 0.75 C 36 12 17 23 24 1.58 0.75 D 42 12 17 26 27 1.10 0.75 A 42 12 17 26 27 1.28 0.75 B 42 12 17 26 27 1.54 0.75 C 42 12 17 26 27 1.78 0.75 D 42 16 17 26 27 1.10 0.70 A 42 16 17 26 27 1.28 0.70 B 42 16 17 26 27 1.54 0.89 C 42 16 17 26 27 1.78 0.89 D 48 12 17 30 30 1.26 0.75 A 48 12 17 30 30 1.42 0.75 B 48 12 17 30 30 1.71 0.75 C 48 12 17 30 30 1.96 0.75 D 440 AMERICAN GAS-ENGINEERING PRACTICE. TABLE NO. 9 (Continued). (Dimensions in Inches.) Nominal Diameter. jj p N T\ To Class. E F * 2 48 16 17 30 30 .26 0.70 A 48 16 17 30 30 .42 0.70 B 48 16 17 30 30 .71 0.89 C 48 16 17 30 30 .96 0.89 D 54 12 19 33 33 .35 0.75 A 54 12 19 33 33 .55 0.75 B 54 12 19 33 33 1.90 0.75 C 54 12 19 33 33 2.23 0.75 D 54 16 19 33 33 1.35 0.70 A 54 16 19 33 33 1.55 0.70 B 54 16 19 33 33 1.90 0.89 C 54 16 19 33 33 2.23 0.89 D 60 12 21 36 36 1.39 0.75 A 60 12 21 36 36 1.67 0.75 B 60 12 21 36 36 2.00 0.75 C 60 12 21 36 36 2.38 0.75 D 60 16 21 36 36 1.39 0.70 A 60 16 21 36 36 1.67 0.70 B 60 16 21 36 36 2.00 0.89 C 60 16 21 36 36 2.38 0.89 D .- ^-H. - i -s-hK-r-M|-4 N TABLE NO. 10. REDUCERS. TYPE 1. (Dimensions in Inches.) Nom. Diam. s K M N L R ^ T 2 Class. E F 6 4 10 3.3 14.7 2 30 3 0.55 0.52 D 8 4 10 5.3 12.7 2 30 4 0.60 0.52 D 8 6 10 3.9 14.1 2 30 4 0.60 0.55 D 10 4 10 7.1 10.9 2 30 5 0.68 0.52 D 10 6 10 6.0 12.0 2 30 5 0.68 0.55 D 10 8 10 4.4 13.6 2 30 5 0.68 0.60 D 12 6 10 7.9 10.1 2 30 6 0.75 0.55 D 12 8 10 6.6 11.4 2 30 6 0.75 0.60 D 12 10 10 4.8 13.2 2 30 6 0.75 0.68 D PIPE AND MISCELLANEOUS DATA. 441 TABLE NO. 11. REDUCERS. TYPE 2. (Dimensions in Inches.) Nominal Diameter. V S TI T 2 Class. E F 14 6 20 8 0.66 0.55 A-B 14 6 20 8 0.82 0.55 C-D 14 8 20 8 0.66 0.60 A-B 14 8 20 8 0.82 0.60 C-D 14 10 20 8 . 0.66 0.66 A-B 14 10 20 8 0.88 0.68 C-D 14 12 20 8 0.66 0.66 A-B 14 12 20 8 0.82 0.75 C-D 16 6 20 8 0.70 0.55 A-B 16 6 20 8 0.89 0.55 C-D 16 8 20 8 0.70 0.60 A-B 16 8 20 8 0.89 0.60 C-D 16 10 20 8 0.70 0.68 A-B 16 10 20 8 0.89 0.68 C-D 16 12 20 8 0.70 0.70 A-B 16 12 20 8 0.89 0.75 C-D 16 14 20 8 0.70 0.66 A-B 16 14 20 8 0.89 0.82 C-D 18 8 20 8 0.75 0.60 A-B 18 8 20 8 0.96 0.60 C-D 18 10 20 8 0.75 0.68 A-B 18 10 20 8 0.96 0.68 C-D 18 12 20 8 0.75 0.75 A-B 18 12 20 8 0.96 0.75 C-D 18 14 20 8 0.75 0.66 A-B 18 14 20 8 0.96 0.82 C-D 18 16 20 8 0.75 0.70 A-B 18 16 20 8 0.96 0.89 C-D 20 10 26 8 0.80 0.68 A-B 20 10 26 8 1.03 0.68 C-D 442 AMERICAN GAS-ENGINEERING PRACTICE. TABLE NO. 11 (Continued). (Dimensions in Inches.) Nominal Diameter. V s T! T 2 Class. E F 20 12 20 8 0.80 0.75 A-B 20 12 20 8 1.03 0.75 C-D 20 14 26 8 0.80 0.66 A-B 20 14 26 8 1.03 0.82 C-D 20 16 26 8 0.80 0.70 A-B 20 16 26 8 1.03 0.89 C-D 20 18 26 8 0.80 0.75 A-B 20 18 26 8 1.03 0.96 C-D 24 14 26 8 0.89 0.66 A-B 24 14 26 8 1.16 0.82 C-D 24 16 26 8 0.89 0.70 A-B 24 16 26 8 1.16 0.89 C-D 24 18 26 8 0.89 0.75 A-B 24 18 26 8 1.16 0.96 C-D 24 20 26 8 0.89 0.80 A-B 24 20 26 8 1.16 1.03 C-D 30 18 26 8 0.88 0.75 A 30 18 26 8 1.03 0.75 B 30 18 26 8 1.20 0.96 C 30 18 26 8 1.37 0.96 D 30 20 26 8 0.88 0.80 A 30 20 26 8 1.03 0.80 B 30 20 26 8 1.20 1.03 C 30 20 26 8 1.37 1.03 D 30 24 26 8 0.88 0.88 A 30 24 26 8 1.03 0.89 B 30 24 26 8 1.20 1.16 C 30 24 26 8 1.37 1.16 D 36 20 32 8 0.99 0.80 A 36 20 32 8 1.15 0.80 B 36 20 32 8 1.36 1.03 C 36 20 32 8 1.85 1.03 D 36 24 32 8 0.99 0.89 A 36 24 32 8 1.15 0.89 B 36 24 32 8 1.36 1.16 C 36 24 32 8 1.58 1.16 D 36 30 32 8 0.99 0.88 A 36 30 32 8 1.15 1.03 B 36 30 32 8 1.36 1.20 C 36 30 32 8 1.58 1.37 D 42 20 32 8 1..10 0.80 A 42 20 32 8 1.28 0.80 B 42 20 32 8 1.54 1.03 C 42 20 32 8 1.78 1.03 D 42 24 32 8 1.10 0.89 A 42 24 32 8 1.28 0.89 B 42 24 32 8 1.54 1.16 C 42 24 32 8 1.78 1.16 D PIPE AND MISCELLANEOUS DATA. 443 TABLE NO. 11 (Continued). (Dimensions in Inches.) Nominal Diameter. E F V S Ti T 2 Class. 42 30 32 8 .10 0.88 A 42 30 32 8 .28 .03 B 42 30 32 8 .54 .20 C 42 30 32 8 .78 .37 D 42 30 66 8 .10 0.88 A 42 30 66 8 .28 .03 B 42 30 66 8 .54 .20 C 42 30 66 8 1.78 .37 D 42 36 32 8 1.10 0.99 A 42 36 32 8 1.28 .15 B 42 36 32 8 1.54 .36 C 42 36 32 8 1.78 .58 D 42 36 66 8 1.10 0.99 A 42 36 66 8 1.28 .15 B 42 36 66 8 .54 .36 C 42 36 66 8 .78 .58 D 48 30 32 8 .26 0.88 A 48 30 32 8 .42 .03 B 48 30 32 8 .71 .20 C 48 30 32 8 .96 .37 D 48 30 132 8 .26 0.88 A 48 30 132 8 1.42 1.03 B 48 30 132 8 1.71 1.20 C 48 30 132 8 1.96 1.37 D 48 36 32 8 1.26 0.99 A 48 36 32 8 1.42 1.15 B 48 36 32 8 1.71 .36 C 48 36 32 8 1.96 .58 D 48 36 132 8 1.26 .99 A 48 36 132 8 1 .42 .15 B 48 36 132 8 1.71 .36 C 48 36 132 8 1.96 .58 D 48 42 32 8 1.26 .10 A 48 .42 32 8 1. 42 .28 B 48 42 32 8 1.71 .54 C 48 42 32 8 1.96 .78 D 48 42 132 8 1.26 .10 A 48 42 132 8 1.42 .28 B 48 42 132 8 1.71 .54 C 48 42 132 8 1.96 .78 D 54 36 66 8 1.35 0.99 A 54 36 66 8 1.55 .15 B 54 36 66 8 1.90 .36 C 54 36 66 8 2.23 .58 D 54 36 132 8 1.35 0.99 A 54 36 132 8 1.55 .15 B 54 36 132 8 1.90 .36 C 54 36 132 8 2.23 .58 D 444 AMERICAN GAS-ENGINEERING PRACTICE. TABLE NO. 11 (Continued). (Dimensions in Inches.) Nominal I )iameter. E F V S TI T 2 Class. 54 42 66 8 1.35 1.10 A 54 42 66 8 1.55 . 1.28 A 54 42 66 8 1.90 1.54 C 54 42 66 8 2.23 1.78 D 54 42 132 8 1.35 1.10 A 54 42 132 8 1.55 .28 B 54 42 132 8 1.90 .54 C 54 42 132 8 2.23 .78 D 54 48 66 8 1.35 .26 A 54 48 66 8 1.55 .42 B 54 48 66 8 1.90 1.71 C 54 48 66 8 2.23 1.96 D 54 48 132 8 1.35 1.26 A 54 48 132 8 1.55 1.42 B 54 48 132 8 1.90 1.71 C 54 48 132 8 2.23 1.96 D 60 36 66 8 1.39 0.99 A 60 36 66 8 1.67 1.15 B 60 36 66 8 2.00 1.36 C 60 36 66 8 2.38 1.58 D 60 36 132 8 1.39 0.99 A 60 36 132 8 1.67 1.15 B 60 36 132 8 2.00 1.36 C 60 36 132 8 2.38 .58 D 60 42 66 8 1.39 .10 A 60 42 66 8 1.67 .28 B 60 42 66 8 2.00 .54 C 60 42 66 8 2.38 .78 D 60 42 132 8 1.39 .10 A 60 42 132 8 1.67 .28 B 60 42 132 8 2.00 .54 C 60 42 132 8 2.38 .78 D 60 48 66 8 1.39 .26 A 60 48 66 8 1.67 .42 B 60 48 66 8 2.00 .71 C 60 48 66 8 2.38 .96 D 60 48 132 8 1.39 .26 A 60 48 132 8 1.67 .42 B 60 48 132 8 2.00 .71 C 60 48 132 8 2.38 .96 D 60 54 66 8 1.39 .35 A 60 54 66 8 1.67 .55 B 60 54 66 8 2.00 .90 C 60 54 66 8 2.38 .23 D 60 54 132 8 1.39 .35 A 60 54 132 8 1.67 .55 B 60 54 132 8 2.00 .90 C 60 54 132 8 2.38 2.23 D PIPE AND MISCELLANEOUS DATA. 445 TABLE NO. 12. SLEEVES. (Dimensions in Inches.) Nominal Diameter. Class. A B L O T 4 D 1.50 1.30 10 5.80 0.65 6 D 1.50 1.40 10 7.90 0.70 8 D 1.50 1.50 12 10.10 0.75 10 D 1.50 1.60 12 12.20 0.80 12 D 1.50 1.70 14 14.30 0.85 14 A-B 1.50 1.70 15 16.20 0.85 14 C-D 1.50 1.80 15 16.50 0.90 16 A-B 1.75 1.80 15 18.50 0.90 16 C-D 1.75 1.90 15 18.90 1.00 18 A-B 1.75 1.90 15 20.60 0.95 18 C-D 1.75 2.10 15 21.00 1.05 20 A-B 1.75 2.00 15 22.70 .00 20 C-D 1.75 2.30 15 23.10 .15 24 A-B 2.00 2.10 15 26.90 .05 24 C-D 2.00 2.50 15 27.40 .25 30 A 2.00 2.30 15 32.80 .15 30 B 2.00 2.30 15 33.10 .15 30 C 2.00 2.60 15 33.50 .32 30 D 2.00 3.00 15 33.80 .50 36 A 2.00 2.50 15 39.00 .25 36 B 2.00 2.80 15 39.40 .40 36 C 2.00 3.10 15 39.80 .60 36 D 2.00 3.40 15 40.20 .80 36 A 2.00 2.50 20 39.00 .25 36 B 2.00 2.80 20 39.40 .40 36 C 2.00 3.10 20 39.80 .60 36 D 2.00 3.40 20 40.20 .80 42 A 2.00 2.80 15 45.30 .40 42 B 2.00 3.00 15 45.60 .50 42 C 2.00 3.40 15 46.20 .75 42 D 2.00 3.80 15 46.70 .95 42 A 2.00 2.80 20 45.30 .40 42 B 2.00 3.00 20 45.60 .50 42 C 2.00 3.40 20 46.20 1.75 42 D 2.00 3.80 20 46.70 1.95 446 AMERICAN GAS-ENGINEERING PRACTICE. TABLE NO. 12 (Continued). (Dimensions in Inches.) Nominal Diameter. Class. A B L T 48 A 2-.00 3.00 15 51.60 .50 48 B 2.00 3.30 15 51.90 .65 48 C 2.00 3.80 15 52.50 .95 48 D 2.00 4.20 15 53.10 .20 48 A 2.00 3.00 20 51.60 .50 48 B 2.00 3.30 20 51.90 .65 48 C 2.00 3.80 20 52.50 .95 48 D 2.00 4.20 20 53.10 2.20 54 A 2.25 3.20 15 57.70 1.60 54 B 2.25 3.60 15 58.20 1.80 54 C 2.25 4.00 15 58.90 2.15 54 D 2.25 4.40 15 59.50 2.45 54 A 2.25 3.20 20 57.70 1.60 54 B 2.25 3.60 20 58.20 1.80 54 C 2.25 4.00 20 58.90 2.15 54 D 2.25 4.40 20 59.50 2.45 60 A 2.25 3.40 15 63.90 1.70 60 B 2.25 3.70 15 64.50 1.90 60 C 2.25 4.20 15 65.30 2.25 60 D 2.25 4.70 15 65.90 2.60 60 A 2.25 3.40 20 63.90 1.70 B 2.25 3.70 20 64.50 1.90 C 2.25 4.20 20 65.30 2.25 D 2.25 4.70 20 65.90 2.60 PIPE AND MISCELLANEOUS DATA. 447 A and B as tabulated in Table No. 1. = 2.50" for 12" to 24" incl. X=1.25" for 12" to 24" incl. Y=1.62" for 12" to 24" incl. G = 3.00" for 30" to 60" incl. X=1.50" for 30" to 60" incl. Y=2.00" for 30" to 60" incl. TABLE NO. 13. CAPS. (Dimensions in Inches.) Nominal Diameter D O H T M K Z R Class. 4 4.0 5 7 4 10 0.60 D 6 4.0 7.8 4.15 0.65 D 8 4.0 10.0 4.75 0.75 .... D 10 4.0 12.1 4.75 0.75 1.50 6.75 .... 16.2 D 12 4.0 14.2 4.75 0.75 1.75 0.75 .... 18.7 D 14 4.0 16.1 4.90 0.90 1.90 0.75 22.4 A-B 14 4.0 16.45 4.90 0.90 1.90 0.75 22.4 C-D 16 4.0 18.4 5.00 1.00 2.00 0.75 27.0 A-B 16 4.0 18.8 5.00 .00 2.00 0.75 27.0 C-D 18 4.0 20.5 5.00 .00 2.00 1.00 32.0 A-B 18 4.0 20.92 5.00 .00 2.00 1.00 .... 32.9 C-D 20 4.0 22.6 5.00 .00 3.00 1.00 1.25 18.2 A-B 20 4.0 23.06 5.00 .00 3.00 1.00 1.50 18.2 C-D 24 4.0 26.8 5.25 .05 3.50 1.00 1.30 23.5 A-B 24 4.0 27.32 5.25 .05 3.50 1.00 1.55 23.5 C-D 448 AMERICAN GAS-ENGINEERING PRACTICE. TABLE NO. 13 (Continued). (Dimensions in Inches.) Nominal Diam. D O H T M K z R Class. 30 4.5 32.74 5.75 .15 3.50 .15 1.30 34.8 A 30 4.5 33.00 5.75 .15 3.50 .15 1.50 34.8 B 30 4.5 33.40 5.75 .15 3.50 .15 1.70 34.8 C 30 4.5 33.74 5.75 .15 3.50 .15 1.90 34.8 D 36 4.5 38.96 6.00 .25 4.00 .25 1.63 44.0 A 36 4.5 39.30 6.00 .30 3.95 .25 1.88, 44.0 B 36 4.5 39.70 6.00 .35 3.90 .25 2.08 44.0 C 36 4.5 40.16 6.00 .40 3.85 .25 2.30 44.0 D 42 5.00 45.20 7.00 1.40 4.00 .40 2.00 63.5 A 42 5.00 45.50 7.00 1.50 3.90 .40 2.25 63.5 B 42 5.00 46.10 7.00 1.60 3.80 1.40 2.55 63.5 C 42 5.00 46.58 7.00 1.70 3.70 1.40 2.80 63.5 D 48 5.00 51.50 7.00 1.70 4.00 1.50 2.10 76.5 A 48 5.00 51.80 7.00 1.90 3.80 1.50 2.40 76.5 B 48 5.00 52.40 7.00 2.00 3.70 1.50 2.70 76.5 C 48 5.00 52.98 7.00 2.10 3.60 1.50 3.00 76.5 D 54 5.5 57.66 7.5- 1.90 4.50 1.50 2.20 82.0 A 54 5.5 58.10 7.5 2.00 4.40 1.50 2.50 82.0 B 54 5.5 58.80 7.5 2.10 4.30 1.50 2.80 82.0 C 54 5.5 59.40 7.5 2.20 4.20 1.50 3.10 82.0 D 60 5.5 63.80 7.5 2.00 4.50 1.50 2.30 99.0 A 60 5.5 64.40 7.5 2.10 4.40 1.50 2.60 99.0 B 60 5.5 65.20 7.5 2.20 4.30 1.50 2.90 99.0 C 60 5.5 65.82 7.5 2.30 4.20 1.50 3.20 99.0 D --L 3 RIBS SPIGOT fee/VD 2. RIBS E actual outside diameter, Table No. 1. TABLE NO. 14. PLUGS. (Dimensions in Inches.) Nominal Diameter. L M Number of Ribs. TI T 2 T 3 Class. 4 5.5 0.50 0.40 0.20 D 6 5.5 f .... 0.60 0.40 0.20 D 8 5.5 2.0 2 0.60 0.40 0.20 D 10 6.0 2.0 2 0.70 0.50 0.20 D 12 6.0 2.0 2 0.75 0.50 0.20 D 14 6.0 2.0 2 0.70 0.50 0.20 A-B 14 6.0 2.0 2 0.75 0.50 0.20 C-D 16 6.5 2.0 3 0.70 0.50 0.30 A-B 16 6.5 2.0 3 0.80 0.60 0.30 C-D 18 6.5 2.5 3 0.75 0.60 0.30 A-B 18 6.5 2.5 3 0.85 0.60 0.30 C-D 20 6.5 2.75 3 0.85 0.60 0.30 A-B 20 6.5 2.75 3 1 .00 0.60 0.30 C-D PlPEAND MISCELLANEOUS DATA. 449 /"" |-_ TABLE NO. 15. BELL PLUG. (Dimensions in Inches.) Nom. Diam. Class. A B E J K L M N I T 24 A-B 25.95 25.8 8 4.5 2.5 2.25 5.00 2.25 50 0.89 24 C-D 26.45 26.32 8 4.5 2.5 2.25 5.00 2.25 50 1.16 30 A 31.86 31.74 8 4.5 2.62 2.25 5.25 2.5 64 0.88 30 B 32.12 32.00 8 4.5 2.62 2.25 5.25 2.5 64 .03 30 C 32.52 32.40 8 4.5 2.62 2.25 5.25 2.5 64 .20 30 D 32.86 32.74 8 4.5 2.62 2.25 5.25 2.5 64 .37 36 A 38.08 37.96 8 5.75 3.12 2.25 6.25 2.75 84 0.99 36 B 38.42 38.30 8 5.75 3.12 2.25 6.25 2.75 84 .15 36 C 38.82 38.70 8 5.75 3.12 2.25 6.25 2.75 84 .36 36 D 39.28 39.16 8 5.75 3.12 2.25 6.25 2.75 84 .58 42 A 44.32 44.20 9 6.25 3.37 2.25 6.75 2.87 100 .10 42 B 44.62 44.50 9 6.25 3.37 2.25 6.75 2.87 100 .28 42 C 45.22 45.10 9 6.25 3.37 2.25 6.75 2.87 100 1.54 42 D 45.70 45.58 9 6.25 3.37 2.25 6.75 2.87 100 1.78 48 A 50.62 50.50 9 6.75 3.62 2.25 7.25 3.00 120 1.26 48 B 50.92 50.80 9 6.75 3.62 2.25 7.25 3.00 120 1.42 48 C 51.52 51.40 9 6.75 3.62 2.25 7.25 3.00 120 1.71 48 D 52.10 51.98 9 6.75 3.62 2.25 7.25 3.00 120 1.96 54 A 56.78 56.66 9 7.25 3.87 2.25 7.75 3.12 140 1.35 54 B 57.22 57.10 9 7.25 3.87 2.25 7.75 3.12 140 1.55 54 C 57.92 57.80 9 7.25 3.87 2.25 7.75 3.12 140 1.90 54 D 58.52 58.40 9 7.25 3.87 2.25 7.75 3.12 140 2.23 60 A 62.92 62.80 9 7.75 4.12 2.25 8.25 3.25 160 1.39 60 B 63.52 63.40 9 7.75 4.12 2.25 8.25 3.25 160 1.67 60 C 64.32 64.20 9 7.75 4.12 2.25 8.25 3.25 160 2.00 60 D 64.94 64.82 9 7.75 4.12 2.25 8.25 3.25 160 2.38 450 AMERICAN GAS-ENGINEERING PRACTICE. U- -J TABLE NO. 16. OFF-SETS. (Dimensions in Inches.) Nominal Diameter. N 5 K L R T Class. 4 ' 2 10 13.85 35.85 8 0.52 D 6 2 10 24.25 46.25 14 0.55 D 8 2 10 26.00 48.00 15 0.60 D 10 2 10 27.70 49.70 16 0.68 D 12 2 10 29.45 51.45 17 0.75 D 14 2 10 31.20 53.20 18 0.66 A-B 14 2 10 31.20 53.20 18 0.82 O-D 16 2 10 32.90 54.90 19 0.70 A-B 16 2 10 32.90 54.90 19 0.89 C-D 20- H* BOUT* Hov.es TABLE NO. 17. MANHOLE PIPES. (Dimensions in Inches.) Norn. Diam. I N T Class. Norn. Diam. L N T Class. 30 17 21 0.88 A 48 17 30 1.26 A 30 17 21 .03 B 48 17 30 1.42 B 30 17 21 .20 C 48 17 30 1.71 C 30 17 21 .37 D 48 17 30 1.96 D 36 17 24 0.99 A 54 19 33 .35 A 36 17 24 .15 B 54 19 33 .55 B 36 17 24 .36 C 54 19 33 .90 G 36 17 24 .58 D 54 19 33 .23 D 42 17 27 .10 A 60 21 36 .39 A 42 17 27 .28 B 60 21 36 .67 B 42 17 27 .54 C 60 21 36 2.00 C 42 17 27 .78 D 60 21 36 2.38 D PIPE AND MISCELLANEOUS DATA. 451 NOTE REGARDING LUGS ON BRANCHES. Lugs of the form and dimensions given in the preceding tables are to be placed on the bells of side outlets on all branches, on outlets 12 inches in diameter and larger when desired. NUMBER AND WEIGHTS OF LUGS ON OUTLETS OF DIFFERENT SIZES. Diameter of Outlet, Inches. No. of Pairs of Lugs. Weight of Lugs on One Bell, Lbs. Diameter of Outlet, Inches. No. of Pairs of Lugs. Weight of Lugs on One Bell, Lbs. 12 4 32 36 6 80 14 4 32 42 8 111 16 6 56 48 8 114 18 6 56 54 Class A and B 8 126 20 6 56 54 " C " D 8 i 134 24 6 56 60 " A " B 8 , 129 30 6 80 60 " C " D 8 I 137 ! Two pairs of lugs to be placed on the vertical axis of eachibell, the others to be spaced at equal distances around the circumference. If branches are made without lugs, the standard weighjts given in the table should be increased in accordance with the weights giv^n above. A METHOD OF " CUTTINQ-IN " SPECIALS. Made in 4" to 16" diameters, inclusive, and especially desig- nated for use where it is necessary to cut a street main for set- Cut A. ting an extra hydrant, the opening of a new street, or for the introduction of any other large service. Cat B. The above cuts illustrate the advantage of the "Cutting-in" Special, one end of which is enlarged back of the bell, and with 452 AMERICAN GAS-ENGINEERING PRACTICE. its face made slightly oblique to the axis of the Special. Thus it is readily inserted as shown and necessitates but two joints. At the back of the bell and parallel to its face there is a projec- tion or rib which fits the main pipe and forms a stop for the yarn. The Special is so made as to be adapted to varying thicknesses of pipes and presents no difficulty in making up. TABLE OF STANDARD SIZES, CUTTING-IN TEES. Diameter in Inches. Laying Length in Inches. Approximate Weight in Lbs. Will take Pipe of Inside Diameter, Thickness, Inches. Inches. 3X 3 16 90 3 4X 4 19 100 4 &to& 6X 6 21 190 6 | f 8X 8 23 290 8 10X10 24 380 10 JL a. 12X12 24 580 12 X I 14X14 31 780 14 * tt 16X16 31 950 16 i 1 Side outlets of different diameter than main run, to order on Among the advantages in the use of this Special are diminished excavations, saving in joints and labor, absence of holding and blocking up of pieces, variation of an inch or two in length of piece cut out without causing trouble, and lessened length of time the water needs to be shut off. In addition, the "Cutting-in" Special may be used as an ordinary special if necessary, and where there is any uncertainty as to the location of side streets, it is cheaper to make the work continuous and " cut-in" branches with this Special as required. There are also SHORT LENGTHS OF PIPE with the PATENTED BELL and a SPIGOT or with the PATENTED BELL and an ORDINARY BELL END. Where a change of grade or alignment is not sufficient to require a curved pipe, this form of short pipe admirably answers the purpose. With them also a break can be repaired without a sleeve with the least excavation and with but one extra joint. Under ordinary circumstances, however, the author recommends the method illustrated in Cut A. PIPE AND MISCELLANEOUS DATA. 453 FLEXIBLE=JOINT PIPE. Made in Lengths to Lay 12 Feet. The joint A is that usually employed, and admits of the lead gasket moving upon the interior surface of the bell, which is care- fully machined. This design is sometimes modified by adding one or more lead grooves upon the spigot end. A. Bell End, Machined Inside. The design C is a more expensive joint, intended for the larger size of pipe, especially when they are used for conveying water under considerable pressure. This joint has a split retaining ring or collar bolted to the hub, as shown, forming a very secure FLEXIBLE-JOINT PIPE. (Weights are approximate only.) Inside Diameter of Pipe, Inches. Thickness of Shell in Inches. Weight per Length, Lbs. Lead per Joint, Lbs. Inside Diameter of Pipe, Inches. Thickness of Shell in Inches. Weight T pei Y Length, Lbs. Lead per Joint, Lbs. 4 A 350 10 16 ft 2190 77 4 A 280 10 16 ft 1660 77 6 1 550 15 18 1 2640 93 6 440 15 18 1900 93 8 5 730 21 20 3220 112 8 I 590 21 20 li- 2560 112 10 ft 1000 28 24 ls ' 4020 144 10 & 830 28 24 3440 144 12 H 1410 38 30 11 6190 181 12 f 1100 38 30 1 4870 181 14 i 1770 64 36 If 8800 250 14 ft 1450 64 36 l| 6770 250 454 AMERICAN GAS-ENGINEERING PRACTICE. connection. For large diameters, these C joints made in short lengths may be used for convenience in handling or in connection with a line partly made up of ordinary bell-and-spigot pipe, though usually resulting in extra expense; full-length pipe, necessitating fewer joints, are generally to be preferred. In standard flexible- joint pipe the maximum deviation per- mitted by the joint is 10, taken in any direction. In selecting the thickness of pipe for a submerged line, the internal pressure under which it will be in service is seldom the determining factor, as ample allowance should be made to mini- C. Spigot End, Machined Outside and Fitted with Retaining Ring or Collar, Complete with Bolts. mize the risk of breakage in laying, and to withstand external shocks from floating ice or other objects. The enlarged hubs naturally add materially to the weight of flexible-joint piping; and the thicknesses and weights suggested in the table may be taken as in line with good practice. Made regularly in lengths to lay about twelve (12) feet. A full assortment of flexible-joint pipe of design A, and of about the weights given in the table, usually in stock. Design C to order only. Short sections, design C, of sizes 20" diameter and upward, for laying between ordinary pipe, to order. Inquiries should state the approximate quantity of pipe, the thickness of shell, or weight per length, and time and place of delivery desired. PIPE AND MISCELLANEOUS DATA. 455 Knuckle-joints. Made with ordinary bell, bell-and-spigot, or flanged ends. These short sections are used in making river crossings in connection with regular flange or bell-and-spigot pipe. The larger sizes with cast-iron or steetriveted flange pipe make an excellent arrangement for intakes with floating screen. Flanged joints are drilled only to order. KNUCKLE-JOINTS, SHORT SECTIONS. STYLE A. Laying Length. Approximate Weight in Lbs. Inside Thick- Outside Joint with T:~* Diameter ness of Diameter Bell or umuv with. of Pipe, Inches. Pipe, Inches. of Flange, Inches. Bell Ends, Inches. Bell and Spigot, Inches. Flange Ends, Inches. Bell-and- spigot Ends, without Lead. Flange Ends, without Lead. Lead per Joint. 4 A 9 10* 22f 10* 100 80 10 6 11 11* 23* Hi 140 100 15 8* ft 13* 12* 131 220 160 21 10 1 16 26| 14* 310 230 28 12 tt 19 16* 28 16 440 350 38 14 21 17f 29| 17f 580 460 64 16 1 23 19* 3H 19* 780 640 77 18 *l 25 21* 33 1 21 i 990 800 93 20 i 27* 23 35 23 1280 1050 112 24 i^ 32 25 37* 25* 1700 1410 144 30 i* 38J 29 41 29 2720 2300 181 36 45f 32* 44* 32* 4100 3570 250 456 AMERICAN GAS-ENGINEERING PRACTICE. Connecting Mains. In a paper upon this subject Mr. Forstall advocates the following table to determine the size of connections and the method of making same: NEW MAIN TO EXISTING MAINS. Size of New Mains. Size of Existing Mains. 30 in. 24 in. 20 in. 16 in. 12 in. 8 in. 6 in. 4 in. 4 inch 6 inch 8 inch 12 inch I 16 inch f 20 inch 24 inch 30 inch Saddle Pee or Hat Fig. Insert Branch Saddle Piece Insert Branch Saddle P'ce Split si' ves Insert Branch Insert Branch Insert Branch Insert Branch Insert Branch Insert Branch Tools for Laying Cast=iron Pipes. After the material, in- cluding pipe and fittings, yarn, cement, or lead, has been ordered, the following tools will be needed for the work. The number of laborers required and the tools needed will, of course, vary with the size and length of the main to be laid. If a considerable main, say 4, 6, or 12 inch, to each fifty laborers two pipe handlers in trench, one yarner, four calkers, one lead-jointer, and one blocking man will be sufficient to start the men. 1 tapping-machine, I" to 2" taps. 4 calking-hammers. 2 Trimo wrenches, 18" and 24". 4 8-pound striking-hammers for use with dog-chisel in cutting cast-iron pipes. 2 15" monkey-wrenches. 3 dog-chisels with handles. 1 2-lb. machinists' hammer. 1 12-lb. sledge-hammer. 2 paving-hammers. 4 sets calking-tools 8 pieces to the set. 6 lead-chisels. 4 split-chisels. 4 yarning-irons. 6 cold-chisels. 6 diamond-points. 2 5-ft. crowbars. 10 railroad tamping-bars. 6 4" trowels. 1 10" trowel. 2 18" spirit-levels. 1 iron oil-can. PIPE AND MISCELLANEOUS DATA. 457 1 hand-saw. 1 2-man saw. 2 axes. 2 dozen street-lanterns with red globes. 1 dozen iron-plug dirt-pounders. 1 5-gallon kerosene-oil can. 1 15X30 galvanized-iron cement can. 1 100-ft. metallic tape measure. 1 12-ft. pipe-scraper for scraping dirt out of pipe. 1 wheelbarrow. A street-brooms. 1 salamander furnace with lead kettle for same. 2 small lead kettles for pouring joints. 2 pieces Manila rope 30 feet long. 2 tripods. A derrick or crabs. 2 Yale & Town chain-block, or similar make. 4 tunne ling-shovels. 90 railroad-picks. 40 pick-handles. 60 sharp-nose D-handle shovels. 10 flat-nose D-handle shovels for bottom work and street- cleaning. 1 lot assorted gas-bags. These should never be left around in the tool-box, but should be called for as needed. 6 12X18X4" galvanized-iron cement pans. 4 galvanized water buckets. 4 pairs rubber gloves. Wooden plugs or stoppers to fit various size mains. 2 tool-boxes 1 for lighter material and 1 for picks, shovels, crowbars, sledges, etc. 1 or more three-wheel pipe-cutters to cut from f " to 2". 1 threading-machine }" to 1", or Beaver die stock and portable vise. 2 slings of rope. 6 forks (for separating gravel). 2 sets of Lawn horseshoes for tamping (discretionary). 1 set C. I. pipe-cutters, Hall or Rodfield type, with extra links. Under some circumstances on long lines a pneumatic hammer, the compressor being driven by portable gasoline engine and the hammer fitted with calking-tools, may be used to advantage. Wrought=iron Low-pressure Mains. In laying wrought- iron mains the preparation to be made is the same as for cast-iron mains, with the exception that it is not customary in laying low- pressure natural-gas mains to make any provision for laying to grade. There is, of course, some difference in the tools required 458 AMERICAN GAS-ENGINEERING PRACTICE. for the work. In addition to the ordinary tools required by the laborers for digging the trench, etc., the following tools will be needed by the pipe-layers. 2 sets stocks and adjustable (retreating dies) for rechasing and cleaning threads. Swabs for cleaning out the different-size mains. 2 pipe- jacks and boards. 4 pairs of tongs for each size main to be laid. 2 sets of chain- tongs. Diamond-point chisels. Cape-chisels. Machinists' hammers. Crowbars. 1 large air-pump (may be power driven) and gage. The lay -tongs are pipe-tongs made for this kind of work. They are very long, are built heavy, and the bit is held in place by a wedge, and having four sides can be turned and a fresh biting edge obtained. Chain-tongs are best for fittings. Where the work is extensive and a long line of pipe to be run, a power winch, with two hand-wheels and a chuck for holding the pipe, may be used to advantage for screwing home pipe, the joint being started by hand and several lengths being screwed at one operation. Blasting. Where it is necessary to blast in close quarters, or where there is any danger from flying missiles, this danger can be obviated or reduced to the minimum by including in the equipment a heavy rope net under which is placed a lighter rope net, the sides being weighed down by heavy timbers and stones. The mesh of the nets should not exceed three to four inches and the net laid slack. Service Gang and Tools. A service gang usually consists of one fitter and his helper and three to six laborers. A competent fitter may be foreman of this gang. In addition to the service wagon containing pipe-lengths, fittings, etc., and a portable vise, either with bench or attachable to a post, the equipment usual for each gang is: 3 sharp-nose D-handle shovels. 1 set adjustable stock and dies, Beaver type. 1 ratchet stock and dies, for trench and repair work. 1 long-handled shovel for tunneling. 4 railroad-picks with handles. 2 steel forks for separating dirt and gravel. 2 3' 6" crowbars. 1 street-broom. I tapping-machine, }" to 2". PIPE AND MISCELLANEOUS DATA. 459 1 12-lb. sledge. 2 18" and 124" Trimo wrenches. 1 10" Trimo wrench. 2 18" wall-chisels. 1 3-wheel pipe-cutter (with extra wheels) for trench. 1 hatchet. 1 wheel pipe-cutter for vise work. 1 18" bastard file. 1 2-lb. machinist's hammer. 1 oil-can and oil. 3 lanterns and red globes, 1 oil-can for same. 1 small test-pump and gage. No laboring gang should be allowed to assemble upon the work without proper tool and supply equipment, as enormous delays frequently occur, due to the lack of some necessary tool, and the cost of the operation is correspondingly increased. The use of the above inventories will be found of some con- venience for checking up the equipment prior to the start of the day's work. Tool-books containing these inventories should be maintained and the equipment checked off at least twice a day, at which times either the tools or their parts should be in evidence, or the workman to whom issued held responsible. Haulage. An earth-cart should contain 1 cu. yd. An earth-wagon (small size) 1.5 cu. yds. An earth-wagon (large size) 3 cu. yds. Wheelbarrow, 0.1 cu. yd. One single load of earth=27 cu. ft. = 21 bushels. One double load of earth = 54 cu. ft. One cu. yd. of gravel = 18 bu. (in the pit). One cu. yd. of gravel = 24 bu. (when dug). When formed into embankments gravel sinks J in height and decreases \ in bulk. Earth (well-drained) will stand in embankments about l\ to 1. (O'Connor.) Weight of Yarn. In making lead joints for cast-iron mains the weight of calking-yarn necessary is about as follows: WEIGHT OF YARN PER JOINT. Diameter Pipe, Weight of Yarn, Inches. Ounces. 3 3 to 3} 4 3J 6 ' 4f 8 5} 10 6J Diameter Pipe, Weight of Yarn, Inches. Ounces. 12 10 16 12 20 14J 23 211 30 22" 460 AMERICAN GAS-ENGINEERING PRACTICE. Economic Sizes of Purifying=boxes (Newbiggin's 6th Edition) . " Where there are intended to be four purifiers (what we term the four-box system), three always in action, the maximum daily (24- hour) make of gas, expressed in thousand cubic feet, multiplied by the constant 0.6, will give the superficial area in feet for each purifier." Or 60 square feet of area in each box per 100,000 cubic feet make per 24 hours. (Mr. J . A. P. Crisfield, representing the most approved American practice.) Assuming a time contact of 60 seconds (oxide of iron), _ n _ 36007 ~ where V is volume of oxide in cubic feet (between inlet of first box and point of test); R equals rate of "make per hour." This "volume of oxide" may of course be divided by any num- ber necessary to determine the various sizes of boxes found to be convenient. Or the equation may be simplified to read or the volume of oxide between the inlet of the purifiers and the completion of treatment for sulphureted hydrogen must be 1/20 of the rate of flow of gas per hour. This rate of flow should be based upon the maximum or "peak" load of the year's output. Due allowance should of course be made in the installation of boxes for an increase of manufacture. It is also based upon the purification of carburetter water-gas, and should be increased approximately one-third in area of square feet for coal-gas. Mr. CrisfiekTs formula, being based upon an equation between cost of installation, interest, and depreciation of apparatus of boxes, and the cost of labor and operation, undoubtedly consti- tutes the highest authority for American engineers. SUBJECT-INDEX. Abel flash-test for oil, 45 Air, compressed, power required, 225 Air, saturation of, by aqueous vapor, 275, 279 Analyses of steam-boiler fuels, 325 Analysis: carbon dioxide, 23 carburetter oil, 44 fire-clay, 31 sulphur in oxide, 86 iodine method, 87 water-gas scrubber water*, 66 Appliances, gas: industrial, 264 lighting, 260 ranges, cooking, 249 Aqueous vapor in air, 275, 279 Area of circles, 343, 358 Asbestos lining for range ovens, 252, 258 Ash in fuel, influence on value, 327 Barometric temperature correction, 276 Barrel calorimeter, 13 Barring for gas leaks, 162 Barrus throttling calorimeter, 14 Beaume degrees into specific gravity conversion, 286 Blasting of water-gas generator, 3 pressure, 5 Blowers for generator blast, 4 Sturtevant, as exhausters, 107 Boyle's law, expansion of gases, 273 Branch main connections, 456 Brass fittings, red and yellow, 157 Breaks in mains, repairing, 166, 451 Bueb anthracene naphthalene sol- vent, 139 Bunsen's effusion test for specific gravity, 281 Burners: gas-range, 250 incandescent, 260 open flat-flame, 262 tar, water-gas, 62 Calculation by logarithms, 354 Calibration of the Barrus calorimeter, 15 Calorific power of gases, 404 calculation of, 291 Calorimeter, Junker's gas and oil, 292, 297 Simmance-Abady, 299 Calorimetry of steam, 13 Candle-power and heat value, 261 value of carburetter oil, 48 Capacity of consumer's meters, 210 Carbon deposits in superheater, 54 Carbon dioxide: analysis, 23 coal, equivalent of, in flue-gas, 340 water-gas containing, 10, 22 Carburetter brickwork, 36 Carburetter oils: analysis of, 44 comparison of, 50 pump for, 41 storage, 42 supply, 39 Carburetter, operation details, 51 temperature, 49 Cement pipe-joints, 148, 152, 153 Cements and fluxes for pipe, 248 Checker-brick spacing, 37 Chimneys: calculation of height, 332 draught, size, capacity, 334, 336 Chords of circle, polygons, 353 Circular functions, 341, 343, 358, 359 Circumference of circles, 343, 358 Clinker, generator, 6 Coal: anthracite, for generator, 20 461 462 SUBJECT-INDEX. Coal: size of, for generator, 21 Coating services, 201 Coke, qualities of generator, 19 Combustion of gases: calculations, 403, 409 flat-flame burners, 262 temperatures, 302 Complaint meters, 212 > Composition of gases, 267, 268 Compression of air, table, 105 Compression of gas: analysis, 227 candle-power affected by, 226 condensation due to, 226 volume affected by, 227 Conductors of heat, relative values, 308, 310 Condensers, water-gas, 67 principle of, 69 surface condensation, 68 temperatures in, 67 Connections to consumers' meters, 211 Consumption, gas, by industrial ap- pliances, 265 Conversion factors, French-English, 368 compound units, 370 English measures, water, 375 heat-units, 371 temperature scale, 306, 372 weights and measures, 369, 406 Correction, volume, for temperature, 215 Corrosion of services, protection, 201, 203 steel services, 397 Cost of main laying, 168, 176 Cox computers for gas flow, 143, 224 Cutting-in tee for cut main, 451 Cylindrical vessels, table of gallons, 360 Dimensions: cast-iron pipe specials, 199 iron and steel pipe, 204 Distillation data for carburetter oil, 47 Dresser pipe coupling, 156 Drill and tap, numbers for, 399 Drips on high- pressure mains, 160 Efficiency: gas ranges, 249 steam flow in water-gas generator, 10 Effusion test for specific gravity of gases, 281 Engine, gas: cause of pressure pulsa- tions, 223 installation and operation, 266 Evaporation of water, equivalent, 411 Excavating trenches, cost of, 169 Exhausters, gas, 92 capacity, 99 dimensions, 100 installation, 94 operation of, 94 effect of altitude, 103 power required for, 92, 103 pressure, high, 97 revolutions and pressure , 101 slip and losses, 95, 96 Expansion: curves for steam, 320 gases, laws of, 271 liquids and metals, 309 Fire-brick: analysis, 31 carburetter, 36 checker, spacing of, 37 properties of, 27 superheater, 37 Fire-clay for brick, properties of, 29 Fittings:, brass, red and yellow, 157 flanged, 381 Mueller high-pressure, 205 pressure, high, 205 service pipe, 203 weight of malleable iron, 386 Fixtures, gas, requirements, 238 Flexible pipe- joint, ball-and-socket, 453 Flow of gas in pipes, 142, 231 comparison of formulae, 235 Cox high- pressure formula, 224 Pole's formula, 142, 232, 280, 377 Robinson's formula, 377 through orifices, 251 Flow of water in pipe, 327, 329 Flue-gas, coal equivalent of CO 2 in, 340 Flues, boiler-stack, area of, 337 Forcing- jack for running services, 203 Freezing up: gas-holder tanks, 124 services, prevention, 202 French and English units, conversion of, 368 Fuel economizer, Green fuel, 132 Fuels: generator, 2, 19 steam raising, 325 Gages, pressure, 219 Barrus draught, 224 SUBJECT-INDEX. 463 Gages, differential, St. Louis, 221 multiple connections for, 220 Pitot tube, 222 Gallons: cylinders, table of, 380 in box-like vessels, 364 Generator, water-gas: blast-pressure, 26 clinker, 6 fuels compared, 1, 2, 19 linings, 19, 25, 27 operation, 3, 17, 18 safety devices, 27 steam supply, 6 Governors for gas pressure, 218 Grade of gas-mains, 144 Green fuel-economizer 132 Heat values: boiler-fuels, 326 calculation of, 291 candle-power relation, 280 combustion, 404, 408 conductors, comparative, 308 insulation, 252 radiation, 308 from pipe, 391 units, conversion, 306, 371 Holders, gas: calculations, 127 capacity of, 127 pressure by, 122 site of a, 130 tanks, 124 freezing, prevention, 124 patches on, 125 weighting of, 123 wind pressure on, 129 Hydrometer into specific gravity, conversion, 286 Incandescent gas-lighting, 260 Inch, fractions of an, decimal equiva- lents, 352 Industrial gas appliances, 264 consumption, 265 gas-engines, 266 operation, 264 Joints, pipe: see Pipe- joints. Junker's gas-calorimeter, 292 Latent heat of steam, 311 Laying of gas mains, 143, 147 cost of; 172, 176 Lead in pipe-joints, 145, 146, 150 lead wool, 180 Lead pipe, weight of, 389 Leaks in gas-mains, 162 Letheby's globe for specific gravity test, 2&3 Lighting appliances, 260 Linear expansion of metals, coeffi- cients, 309 Logarithms of convenient constants, 352 numbers, 354 Lunette pyrometer, polarizer, 305 Lux gas-balance for specific-gravity test, 285 Mains, gas: breaks, repairing, 166 capacity, 142 cost of, 168 subaqueous, 177 taking up, 177 crosses, designating, 179 deposits, 161 excavation cost, 168 gradient, 144 joints: see Pipe-joints. laying, pneumatic tools, 143, 160 leaks, records of, 162, 163 loading and hauling, 168 repair work, 168 service connection, 163 special for joining break, 451 specials, 182, 420 stoppers, 167 tools for laying, 456 trenching, cost of, 168 Mains, high-pressure gas: anchors, 160 drips, 160 joints, 154 regulators, 159 testing, 160 valves, 159 Mantle burners, 260 Mathematical tables, 341 Measurement: gas, standard unit, 117 generator steam, 7 Melting-points of metals, Princeps alloys, 304 Meters, gas, consumers': capacity, 210 complaint, 212 connections, 211 installation specifications, 237 operation of, 213 Sprague, 214 temperature correction, 215 testing of, 209, 212, 215 Meters, gas, station: by- pass, 114, connections, 113 464 SUBJECT-INDEX. Meters, operation hints, 118 rotary type, 119 sizes, schedule of, 112 volume correction for, 115 Meter, generator-steam, 8 Metric system, conversion of, 368, 406 Mueller high-pressure fittings, 205 Naphthalene: deposits in pipes, 136 preventing deposits, 139 properties of, 135 removal from pipes, 137, 161 solution in benzine, 140 test for, with picric acid, 141 Oils: gas-making, comparison of, 50 grades for carburetter, 43 specific-gravity determination, 285 storage for carburetter, 42, 52 supply for carburetter, 39 Oliphant's formula, flow of gas, 232 Operation of water-gas works, 131 data to be recorded, 132 Ounces pressure converted to inches, 228 Oxide of iron: preparation for puri- fication, 77 revivification of, 82 Paint, water-gas tar, 59 Palladium chloride test for leakage, 163 Patches on gas-holder tanks, 125 Photometer, jet, 131 Pipe: capacity for gas flow, 377 connection for high-pressure, 208 cost of handling, 168 dimensions of, 383 radiating surface of, 391 screw-threads for, 382 service-pipe dimensions, 204 specifications, 414 standard specials, 420 subaqueous, cost of laying, 177 tools for laying, 456 water-pipe, cost of laying, 173 Pipe cement and fluxes, 248 Pipe- joints: ball-and-socket, 152, 153, 453 cement, 148, 152, 153 comparison of various, 152 coupling, Dresser, 156 dimensions, 199 flanged, 380 high- pressure, 154, 159 Pipe-joints: lead, making of, 150 lead wool, 180 specifications, 145 universal, machined, 154 yarn required for, 153, 459 Piping, house: capacity of, 247 gas-engine, 247 gas ranges, 251 installation, 244 sizes of pipe allowed, 240 specifications, 236 weight of pipe, 246 Pitot tube for measuring gas flow, 222 Plates, riveted joints for, 392 Pneumatic tools for cutting mains, 160 Pole's formula for gas flow in pipes, 142, 232, 280, 377 Power required by exhausters, 92 Preheater for carburetter oil, 40 Pressure, gas: adequate, 216 aqueous vapor, effect of, 278, 279 burner pressure, 217 gages, charts, 219 governors, station, street, 218 holder, pressure thrown by, 122 ounces to inches, conversion, 228 Pitot tube for measuring, 222 pulsations, gas-engine, 223 regulators, high- pressure, 159 storage-tanks, high-pressure, 229 square-root table, 280 Pressure, generator blast, 5 Pressure, high, gas-fittings, 205 Pressure, wind, on gas-holders, 129 Princeps alloys, melting-points, 304 Properties of gases, 267 Pump, water-gas tar, 60 Purification practice, 72, 460 analysis of spent oxide, 86 boxes, size of, 460 calculations, 79 capacity of boxes, 74 grids, Jaeger, 90 lime, preparation of, 78 material, purifying, 74 oxide of iron, preparation, 77 testing-boxes, 81 Pyrometer, blue-glass optical, Earn- shaw, 300 Siemens, 311 Radiation of heat, 308, 310 surface of pipes, 391 Ranges, gas: baking, 253 burners, 250 SUBJECT-INDEX. 465 Ranges, care of, 258 cocks, 255 combustion, 255 essentials in selecting, 254 gas consumed, 253 heat insulation, 252 piping, 251 specifications, 259 testing, 256 Reactions in water-gas generator, 23 Receiving-tanks for compressed gas, 230 Recipes, 248, 398 Records of gas-mains, 163 Reflection of heat from surfaces, relative, 310 Regulation of gas pressure, 216 Removing old mains, cost of, 177 Repairing cements for generator, 26 Revivification of iron oxide, 82 in situ, 85 Riveted joints for plates, 392 Robinson's pressure formula for gas flow, 142, 377 Roots of numbers, 341, 357 Rotary station gas-meter, 119 Rules for house piping, 236 Saturated steam, properties of, 323, 324 Schilling's effusion test for specific gravity, 282 Screw-threads for bolts, 407 Scrubbers, water-gas: operation, 64 sprays, 65 trays, 64 water, analysis, 66 Services, 200 coating, 201 connections, 163, 208 fittings, high-pressure, 203 forcing-jack for running, 203 freezing, 202 stoppages, 202 tapping, 200 tools for laying, 458 Siemens pyrometer, 311 Simmance-Abady gas-ealorimeter,299 Sizes of pipe for house piping. 240, 242, 247 Slip in gas-exhausters, 96 losses due to, 98 Solubility of gases in water, 270 Spacing of checker-brick, 37 Special pipe- joint, ball-and-socket, 453 Specials, pipe: cutting-in, special form, 451 designating of, 179 gas-main, 182 Specifications: cast-iron pipe, 414 house piping, 236 pipe- joint, 145 Specific gravity: gas, determination, 281 oils, determination, 285 square roots of, 280 Specific heat: defined, 287 gases, constant pressure, 288 constant volume, 290 calculating mean, 288 solids and liquids, 289, 290, 405 steam, 318 Sprague meter, 214 Sprays for water-gas scrubbers, 65 Square roots of pressure and gravity, 280 Squares, cubes, etc., of numbers, 341, 357 Standards: pipe specials, 420 unit of gas volume, 117 Steam: calorimetry of, 13 equivalent evaporation of water, expansion curves, 320 formulae for, 322 generator, meter to measure, 7 rate of flow into, 9 supply, 6 latent heat of, 311 pressure, temperature, volume, 405 properties, 11, 311 quality, sampling, 12, 16 saturated, properties of, 323 specific heat, 318 specific volume, 315 superheated, 319 total heat, 315 vapor tension, 314 work in steam, 318 Steam-boiler practice, 325 chimney draught, 332 chimney, size of, 336 condensers, 331 flue area, capacity, 337 flue-gases, heat in, 340 fuels, properties of, 325, 335 preheating feed water, 331 water supply, 327, 332 Stoppage of services, 202 Stoppers for mains, 167 Storage-tanks for compressed gas, 229 466 SUBJECT-INDEX. Subaqueous pipe-laying, cost of, 177 Sulphur, compounds in gas, removal of, 73 Sulphureted hydrogen in gas, tests for, 72, 86 Superheated steam, properties of, 319 Superheater: carbon deposits, 53 checker-brick, 55 temperatures, 53 Tanks: box-like, gallons contained, 364 cylindrical, gallons contained, 360 storage of compressed gas, 230 Tap and drill numbers, 399 Tapping mains for services, 165, 200 high- pressure, 267 Tar, water-gas: burner, 62 composition, 58 paint and pavement, 59 pumps, 60 separator, 61 Technical data, 267 Temperature: absolute zero of, 273 air: effect on saturation, 275 effect on barometer, 276 certain industrial ope rat ions, 307 combustion of gases, 302 correction for volume, 215 generator, 6 purifier-boxes, 81 superheater, 53 Temperature measurement : blue glasses, 300 iron, color of highly heated, 305 melting-points, 304, 307 polariscope or lunette, 305 Testing: consumers' meters, 209 gas ranges, 256 Thermometer scales, French-English, 373, 410 Threads of screw-pipe, 382 Tools for laying cast-iron mains, 456 for laying services, 458 Trays for water-gas scrubbers,. 64 Trenches, gas-main: cost of, 169 size of, 146 Units: English and French, con- verted, 368 English measures for water, 376 English weights and measures, 375 Universal pipe- joints, 154 Valves, strength of pipe, 381 Vapor tension: aqueous vapor, 275, 278, 279, 314 mercury vapor, 406 steam, 315 Volume of air, effect of pressure on, 105 Volume of gases, 271 corrections for, 115 effect of pressure 'on, 227 Wash-box, water-gas, 56 Water: analysis, 66 calculations concerning, 401 equivalent evaporation of, 411 flow of, in pipes, friction, 327, 329 lift, suction, various altitudes, 332 measures of, conversion, 376 supply for water-gas works, 133 weight at various temperatures, 330 Water-gas apparatus, 1 Weight: fuels, 326, 335 gases, various, 268, 270 molecular, 274 lead pipe, 389 malleable iron gas-fittings, 386 Weighting of gas-holders, 123 Weights and measures, conversion of, 375 . Welsbach burners, 260 Work in steam, distribution of, 318 Yarn required for pipe- joints, 459 OF THE ( UNIVERSITY j ILIFORJ ADVERTISEMENTS WIDE VARIETY; SUPERIOR QUALITY Gas cocks in sixty styles : straight, round and oval, Meter connections in 1,600 specifications, 3 to 200 light. Service clamps, black or galvanized malleable iron, several hundred specifications. High pressure cocks designed by experts, heavier than actual needs demand. The H. Mueller Mfg. Co. Has for fifty years followed the policy of using only the best metal in all products. Every article tested beyond actual service requirements. Skillful workmen who know the company demands goods that will give the consumer satisfaction and service. Flat Head, Straight Way D-1500lf Century Pattern Service Clamps. Sweat Joint Meter Connections. DECATUR, ILL., West Cerro Gordo St. NEW YORK CITY, 254 Canal, cor. Laf. Phoenix Gas and Improvement Company Harrison Building, Philadelphia, Pa. Contractors and Builders of WATER GAS . . . PLANTS Also Owners and Builders of the Janeway and Logan Oil Gas Process and Apparatus Patents No coal used except for boiler. The cheap- est apparatus to operate where oil is low and coal is high in price. Satisfactory tests made with Indian Territory crude oil, Texas gas oil and California oil. Correspondence Solicited. ESTABLISHED 1861. A. D. CRE9SLER, President. INCORPORATED 1881. KERB MURRAY ENGINEERS AND BUILDERS OF GAS WORKS APPARATUS. PURIFIERS CONDENSERS SCRUBBERS STORAGE TANKS GAS HOLDERS AND STEEL TANKS. PLANS, ESTIMATES AND SPECIFICATIONS PROMPTLY FURNISHED. OFFICE AND .WORKS: FORT WAYNE, INDIANA. The United Gas Improvement Company. OWNERS, LESSEES AND BUILDERS GAS WORKS Originators and Builders of the Standard Double Superheater Lowe Water Gas Apparatus Gas Analysis Apparatus Bar Photometers Special Recording Pressure Gauges BROAD and ARCH STREETS PHILADELPHIA, PA. Warranted to Perfectly Meet Every Requirement of the User of Gas for Fuel. MANUFACTURED BY Schneider & Trenkamp Co. (Div. of American Stove Co.) CLEVELAND. CHICAGO. SAN FRANCISCO. American Meter Co. MANUFACTURERS OF Gas fleters of all descriptions also Meter Provers, Photometrical and Experimental Apparatus, Pressure Gauges, Etc. NEW YORK: N. E. Corner nth Avenue and 47th Street. PHILADELPHIA : N. W. Corner Arch and 22d Streets. CHICAGO : Corner Jefferson and flonroe Streets. THE WITH AUTOMATIC SAFETY CUTOFF for Artificial or Natural Gas. INLET TT7E manufacture Pressure Keducing Valves for any inlet pressure and to VV deliver any outlet pressure desired. Our DUPLEX SENSITIVE GAS GOVERNOR for district service will reduce h : gh pressure gas to inches of water without variation. Absolutely safe and reliable. No complicated mechanism to get out of order. No mercury seals or auxiliary devices. Send for latest- Catalogue. THE CHAPLIN=FULTON MFG. CO., 28=34 Penn Ave., Pittsburg, Pa. VALVOLINE OIL COMPANY Successor to LEONARD & ELLIS. Sole Manufacturers of .TRADE MARK, LUBRICATING OILS. We make a specialty of the manufacture of high grade oils for all classes of fine machinery, at our own Refineries, which we sell direct to users only, under guarantee as to their efficiency and cost, if used as recommended. Trial orders on above conditions, respectfully so- licited. STORES : New York, Boston, Philadelphia, Chicago, Cincinnati, St. Louis, San Francisco, Los Angeles, Portland, Ore. Liverpool, Paris, Hamburg. REFINERIES : Edgewater, N. J. Warren, Pa. Butler, Pa. a v I g nt, 1 bCrtf II Il U It! ^lf fl > o S W 00 C -2 | a ^ fl H 111 - ^ "* H H 3 .9 5 I I OD P^ *H ,14 r^ rrj Jill! - 1 g i I 3 < g rfl 3 ,^"ii 'a . 's * s S t>- d p *1^ 5 .a * 3 'ft 00 "^ b 5> |**1* *5 42 "*H o5 1 1 i I j H-t H ^ -H +3 fl 5 I a" o-l 5-1 = 5li ar a '^ Kfl O 'E a o ^ s, I & 1 a o o o !; !tg 00 0) LL LL D O UJ z h u oj Eo IL c fc *s g: at a te 09 LU 2* ^ "- Or *$! BARTLETT, HAYWARD & CO, BALTIMORE, MD. 100 BROADWAY, N. Y. DESIGNERS AND CONSTRUCTORS OF COMPLETE COAL- AND WATER=QAS PLANTS, Gas Holders Williamson Water-gas Apparatus Purifiers with Ordinary Grids, also Arranged for Jaeger System Condensers Standard Washer Scrubbers Tar Extractors Naphthalene and Cyanogen Washer System (Dr. Bueb) DeBrouwer Electrically Driven, Charging 7 and Discharging Machines DeBrouwer Hot Coke Conveyor Bench Iron Work STRUCTURAL IRON WORK for all Manner of Buildings GLAMORGAN PIPE AND FOUNDRY CO,, LYNCHBURQ, VIRGINIA, MANUFACTURERS OP Cast-iron Pipe, Special Castings, Flange Pipe and Fittings, Hydrants, Valves, Valve Boxes, Meter Boxes, Manhole Frames and Covers, etc. GENERAL FOUNDERS AND MACHINISTS. New York Office: General Office : DRUMMOND & CO., LYNCHBURO, VA. , 82 Broadway . THE SPRAQUE METER CO., BRIDGEPORT, CONN., Manufacturers of Cast Iron Gas Meters Regular and Prepayment FOR Artificial, Natural, Acetylene Qas C Los Angeles, Cal. BRANCHES: ( Toronto, Canada. BOOKS ON GAS MANUFACTURE PUBLISHED AND FOR SALE BY D. VAN NOSTRAND COMPANY 23 MURRAY AND 27 WARREN STS. NEW YORK ABADY, J. Gas Analyst's Manual. (Incorporating F. W. Hartley's " Gas Analyst's Manual" and " Gas Measure- ment.") With figures, tables and folding plates. 8vo, half morocco. Illustrated. 561 pp. London, 1902 net, $6.50 ARNOLD, R. Ammonia and Ammonium Compounds; com- prising their Manufacture from Gas-liquor and from Spent- oxide (^with the recovery from the latter of the by-products, Sulphur, Sulphocyanides, Prussian Blue, etc.) ; special atten- tion being given to the analysis, properties, and treatment of the raw material and final products. A Practical Manual for Manufacturers, Chemists, Gas Engineers, and Drysalters, from personal experience, and including the most recent Discoveries and Improvements. Translated from the Ger- man by Harold G. Colman. Second edition. 12mo, cloth, illustrated. London, 1890 $2.00 BRACKENBURY, C. E. Modern Methods of Saving Labor in Gas Works. With 60 engravings. 8vo, cloth. Illustrated. 64 pp. London, 1900 $2.00 BURNS, W. Illuminating and Heating Gas. A Manual of the Manufacture of Gas from Tar, Oil, and other Liquid Hydro-Carbons, and Extracting Oil from Sewage Sludge. 12mo, cloth. London, 1887 $1.00 BUTTERFIELD, W. J. A. The Chemistry of Gas Manufac- ture. Vol. I. A Practical Hand-book on the Production, Purification and Testing of Illuminating and Fuel Gas, and on the By-Products of Gas Manufacture. For the Use of Students, Chemists, and Gas Engineers. Third Edition. 8vo, cloth, with numerous illustrations. Philadelphia, 1904. Net, $2.50 Vol. II. Testing and Use of Gas In Press CLEGG, S. A Practical Treatise on the Manufacture and Dis- tribution of Coal-Gas. 4to Half Morocco $15.00 COLYER, FRED. Gas Works; Their Arrangement, Construc- tion, Plant and Machinery. With 31 Folding Plates. 8vo, cloth. London, 1884 $3-5 COX'S GAS-FLOW COMPUTER. In cloth case $2.50 CRIPPS, F. S. Gas Holder and Tank (of One Million Cubic Feet Capacity) at the Sutton Gas Works. Embracing Notes on Gas Holder Construction Generally. With folding plates. 8vo, cloth. Illustrated. 33 pp. London, 1898 $1.50 DIBDIN, W. J. Practical Photometry. A Guide to the Study of the Measurement of Light. With tables and numerous figures and folding plates. 8vo, cloth. Illustrated. 227 pp. London, 1889 net, $3.00 Public Lighting by Gas and Electricity. With figures, half-tones, tables and folding plates. 8vo, cloth. Illus- trated. 537pp. London, 1902 net, $8.00 EIJNDHOVEN, A. J. VAN. A Comparison between the Eng- lish and French Methods of ascertaining the Illuminating Power of Coal Gas. 8vo, cloth. London, 1897 $1.60 GRAFTON, W. Handbook of Practical Gas-Fitting. A treat- ise on the distribution of gas in service pipes, the use of coal gas, and the best means of economizing gas from main to burner. For the Use of Students, Plumbers, Gas-Fitters and Gas Managers. With tables and 143 figures, diagrams and folding plates. 12mo, cloth. Illustrated. 328 pp. London, 1901 $2.50 HASLUCK, PAUL N. Practical Gas-Fitting and Gas Manu- facture. With numerous diagrams and engravings. 12mo, cloth, illustrated. London, 1900 $1.00 2 HILLS, H. F. Gas and Gas Fittings. A Handbook of infor- mation relating to coal-gas, water-gas, power-gas, and acety- lene. For the use of Architects, Builders and Gas Consum- ers. With tables and 73 figures and diagrams. 12mo, cloth. Illustrated. 243 pp. London, 1902 net, $1.60 HORNBY, JOHN. Text-Book of Gas Manufacture for Stu- dents. (Bell's Technological Hand-Books.) 12mo, cl., il- lustrated. London, 1896 $1.50 HUGHES, S. Gas Works; Their Construction and Arrange- ment, and the Manufacture and Distribution of Coal Gas. Ninth edition, revised, with notes of recent improvements by Henry O'Connor. With tables, figures and folding plates. 12mo, cloth. Illustrated. 416 pp. London, 1904 $2.40 HUNT C. Gas Lighting; Chemical Technology of; or, Chem- istry in its Applications to Arts and Manufactures. Vol. III. Edited by C. E. Groves and W. Thorp. To which is incorporated Richardson and Watt's " Chemical Technology." 8vo, cloth. London, 1904 net, $3.50 KING'S Treatise on the Science and Practice of the Manufac- ture and Distribution of Coal Gas. Edited by Thomas New- bigging and W. T. Fewtrell. 3 vols., 4to, half morocco. London, 1878 $30.00 LATTA, M. N. Handbook of American Gas Engineering Prac- tice with numerous diagrams and figures 8vo, cloth, illus- trated, 460 pages, New York, 1907 net, $4.50 MENTOR. Self-Instruction in Gas Manufacture. Ele- mentary. Second edition. With figures and tables. 12mo, cloth. Illustrated. London net, $1.50 Self-Instruction in Gas Manufacture. Advanced. With figures and tables. 12mo cloth. Illustrated. London. Net, $1.50 Self-Instruction in Gas Analysis. Constructional. With figures and tables. 12mo, cloth. Illustrated. 134 pp. Lon- don net, $1.50 NEWBIGGING, THOS. Hand-Book for Gas Engineers and Managers. Seventh edition. 4to, morocco, illustrated. London and New York, 1904 net, $6.50 3 O'CONNOR, HENRY. The Gas-Engineer's Pocket-Book. Comprising Tables, Notes and Memoranda relating to the Manufacture, Distribution and Use of Coal Gas, and the Construction of Gas Works. Second edition, revised. 12mo, flexible leather. London, 1903 $3.50 PALAZ, A. Treatise on Industrial Photometry with Special Application to Electric Lighting. Authorized Translation from the French by G. W. Patterson and M. R. Patterson. Second edition, revised. With numerous diagrams and tables. 8vo, cloth. Illustrated. 324 pp. New York, 1896. $4.00 PECKSTON, T. S. Practical Treatise on Gas Lighting; in which the Gas Apparatus Generally in Use is Explained and Illustrated by twenty-two appropriate plates. Third edition. 8vo, cloth. Illustrated. 472 pp. London, 1841 $6.00 POOLE, H. Calorific Power of Fuels. With a collection of auxiliary tables and tables showing the heat of combustion of fuels ; solid, liquid, and gaseous. To which is appended the report of the committee on boiler tests of the American Society of Mechanical Engineers (December, 1899). Second edition, revised and enlarged. With tables, figures and dia- grams. 8vo, cloth. Illustrated. 269 pp. New York, 1905. $3.00 PRACTICAL GAS FITTING. Two illustrated articles re- printed from "The Metal Worker, Plumber and Steam Fitter," describing how to run mains, lay pipes and put up gas fixtures. With diagrams. 12mo, cloth. Illustrated. 116 pp. New York, 1906 $1.00 RICHARDS, WM. A Practical Treatise on the Manufacture and Distribution of Coal Gas. Plates and illustrations. 4to, cloth. London, 1877 $12.00 SPICE, R. P. A Treatise on the Purification of Coal Gas. 8vo, cloth. London, 1884 $3.00 STEVENSON, F. W. Modern Appliances in Gas Manfacture. 8vo, cloth. London, 1901 $2.00 WINKLER, C. Handbook of Technical Gas Analysis. 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