LIBRARY OF CONGRESS. Shelf ..(1^4. UNITED STATES OF AMERICA. :'f!? v A DESCRIPTION OF THE CROSBY Steam Engine Indicator, WITH DIRECTIONS FOR ITS USE, AXD A FEW GENERAL RULES FOR READING AND MEASURING DIAGRAMS. By GEORGE H. CROSBY. ALSO, -^0 AN APPENDIX ; ENUMERATING SPECIALTIES MANUFACTURED CROSBY STEAM G AG E,j&--VA LVE GO. ^0. SkX^J' ' 1880. Copyright, 1880, BY Geohge H. Crosby MilU, Kniglit ^- Co., Printers, 115 Congress Street, Boston. INTRODUCTION In this pamphlet, which accompanies and intro- duces The Crosby Steam Engine Indicator, we desire to draw the attention of all persons interested in the steam engine to the great ad- vantages attending the use of this instrument, and to give such information as will enable any person to use it to the best advantage. It is not inteirded to be a treatise on the Indicator, but merely to present, in an intelligible form for practical use, a few facts which have been gleaned from various sources, namely: the invention of the first Indicator; its primitive condition; subsequent im- provements; as improved by Geo. H. Crosby in 1879; what it is now capable of doing; how to do it; and what to do with it after using. There are also given a few explanations as to the diagram and formulas for calculating the power of the engine. For the benefit of those who desire to become more fully informed as to all that pertains 4 INTRODUCTION. to the Indicator and the properly computed tables, reference is made to the following works : '^ The Steam Engine Indicator/^ by Chas. T. Porter; ^•Elementary Treatise on Steam and the use of the Indicator/^ by J. C. Graham ; " Treatise on the Indicator and Dynamometer," by Thos. I. Main and Thos. Brown; "Engineering Popularized," byWm. Lee Church. GEORGE H. CROSBY. Crosby Steam Gage & Valve Co., 1880. THE STEAM ENGINE INDICATOR, The Steam Eno^ine Indicator is desiofned to register automatically upon paper the pressure of steam in the cylinder at every point of the piston's stroke. The form of the diagram thus drawn b}^ it affords information of a variety of facts not otherwise readily obtained. It must be remembered, however, that it tells nothing about the causes which have determined the form of the fioure which is described ; the operator concludes what these are by a process of reasoning based upon observation and expe- rience and some given data ; errors are here very liable to be committed, and the ability to arrive at accurate conclusions is of the greatest importance, and one of the highest attainments of an engineer. It is now universally conceded that the Indicator is an invalua1)le appendage to the steam engine, and when successfully applied and intelligently read, cannot be too highly estimated. The good condition and economy of every engine made or sold ought to be proved b THE STEAM ENGINE INDICATOR. by the Indicator diagram. In fact, no builders of first-class engines consider their canvass complete without showing a fac-simile of the diao'ram of their enoine. The advantao'e re- o O o sultino' from the use of this instrument, in point of economy, safety and power, is very great, and is recognized by the master mechanics and engineers thoughout the country. HISTORY OF THE INDICATOR. The invention of the Steam Engine Indicator is accredited to James Watt. It has undergone various modifications and improvements since his time. It was at first direct-acting, or, in other words, the pencil was attached directly to the piston-rod, and registered the motion of the same without multiplication ; and was only adapted for slow running engines. In this form it attained its highest point of excellence as manufactured by Wm. McNaught of Scot- land. (See cut No. 1.) The adoption of increased velocities of piston, with greater pressures of steam and higher grades of expan- sion, caused the long and tremulous spring used to oscillate violently by the momentum of the THE STEA31 ENGINE INDICATOR, piston and its connections, and gave as a a serrated fioiire, from which but little infor- mation could be extract- ed. At this time an Improved Steam Engine Indicator was invented by Chas. B. Richards. This Indicator had a short, strong spring, short motion of piston, combined with a lever and links for multiply- ing the motion of the piston and transmitting it to the pencil. These were the distino-uishino: features, and were de- signed to obviate the difficulties before men- tioned, but it was found still subject to grave errors of r egi st ration . The multiplication* of the motion of the piston was not uniform for all portions of the stroke ; the line of motion of result 8 THE STEAM ENGINE INDICATOR. the pencil was not strictly parallel with the line of motion of the piston, describing not a straight line but only an elongated S. But it was a great stride in the right direction, and answered in the absence of anything better, until the still increasing velocities of piston out- stripped its capacity to register without ser- rated lines. (See Diag. No. 7.) This last fault, with its other defects, ^ade it imperative that a more reliable instrument should be made before correct indications could be procured. After considerable study and experiment, Mr. Crosby invented the Improved Parallel Motion Steam Engine Indicator, which obviates the above difficulties to a great extent, and superiority is claimed for this instrument for engines running at any velocity. DESCRIPTION OF THE CROSBY INDICATOR. The principle and action of Indicators are so simple, and to most practical engineers now so well understood, that it will only be neces- sary to give the following cut and description of THE STEAM ENGINE INDICATOR the parts of this instrument to readily appre- ciate the advantages accruing from its use. No. 2. The Crosby Steam Ewjine Indicator, 10 THE STEAM ENGINE INDICATOK. A is a case or jacket enclosing a cylinder, into which a piston is nicely fitted to move Avithout friction ; to the upper side of this piston is attached a steel helical spring, the upper end of which is fastened to the cap or head of the cylinder ; to the upper end of the piston- rod B is directly jointed the short lever C D, whose short end is jointed to the head of a vibrating standard at D, and its long end is jointed to the long lever E F at the point C. The long arm of the lever E F is jointed at its outer extremity to a second vibrating standard at E, and to the other extremity is attached the pencil F. To the case A is permanently attached the horizontal plate G, at one end of which is jointed a corresponding plate H, situated above the former and carrying the revolving drum, covered by the paper cylinder I. To this drum is attached a cord, wound around a groove at its base and carried by the guide wheel K, between the two extra guide wheels L and M ; the guide wheels L and M are attached to the arm N, which swivels around a point in line with the axis of guide wheel K, and is held in its proper position by the thumb-nut O. The drum carrying the paper cylinder I is rotated in one direction by the THE STEAM ENGINE INDICATOR. 11 tension on the cord, and in the reverse direction by the reaction of a spring enclosed therein ; the tension upon this spring may be adjusted to suit by the thumb-nut at the open end of the drum. The plate H, carrying the drum and paper cylinder, is held away from the pencil F by a spring situated between the plates H and G, directly in line with the axis of the drum, until the operator desires to take a diagram. By pressing upon the handle P the paper cylinder is moved forward and the pencil comes in contact with the paper. Immediately upon removing this pressure the paper cylinder automatically assumes its former position. Two adjustable stops determine the amount of this motion and regulate the force with which the pencil presses upon the paper, a hair line beins^ attainable without friction. The bushino- which carries the pencil is bored to receive a graphite or metallic wire, and is supplied with means for holding it in any position desired. The piston-rod is bored at each end almost half its length, leaving a thin partition or stop in the centre ; the upper chamber is used as a reservoir for a lubricant, and is provided with pin-holes close to the partition to allow the oil to flow out and down, and so lubricate the 12 THE STEAM ENGIJSE INDICATOK. rod and piston ; the lower chamber allows the ^team to enter and warm the lubricant, causing it to assume a more limpid form and flow freely in cold weather. The piston-rod is thus made lighter without weakening it materially. A minute portion of felt placed at the bottom of the reservoir will prevent the oil frora flowing too readily. It can be filled at the cross-head with a few drops of oil, by using a common pressure-oiler with a very small nozzle. To adjust the pencil to the proper position for springs of diff'erent scales, the head of the piston- rod is provided with a screw-threaded sleeve and lock-nut, by means of which the pencil may be made to assume any desired height. If it is washed, the guide wheels, etc., may be removed to the opposite end of the plates H and G. The use of a revolving drum for transmitting motion to the paper having been demonstrated to be the best means for the purpose, it has been adopted ; the only prerequisites being sufficient strength of spring and inelasticity of cord to overcome the momentum of the reciprocating parts. In any other devices, such as require a connecting-rod, there is imparted to the latter a tremulous and excessive motion, caused by its length and weight running at high speed when THE STEAM ENGINE INDICATOR. 15 connected with a vibrating arm, which is trans- mitted to the lines of the diagram, thus pro- ducino; error. The greatest degree of accuracy and excel- lence is maintained in the manufacture of this in- strument, and if properly connected and operated its indications may be relied upon implicitly. The advantao^es in usino- this Indicator are numerous, and a few of the most obvious need only be mentioned. First, The motion of the pencil is a uniform multiplication of the piston motion. Second. The parallel motion is a true par- allel and not a geometrical approximation. Third. The weight of the reciprocating parts is greatly reduced. Fourth, The parts which require the most lubricating, viz., the cylinder, piston and rod, are automatically oiled. Fifth. The pencil instead of projecting be- 3^ond the piston-rod several inches is directly behind the piston-rod, only about one quarter of an inch. Sixth, It is more easily operated. With former Indicators it was necessary to be an expert (to some extent), with a delicate sense of touch, to determine just the proper force tcK 14 THE STEAM ENGINE INDICATOR. move the pencil against the paper, so not to tear it or cause undue friction. Now in this Indicator all this is predetermined, and is so nicely adjusted that a child can operate two Indicators — one on each end of the engine cylinder — simultaneousl}^ without the slight- est difficulty, and obtain hair lines without friction. Seventh, This instrument can he used right or left handed, by simply removing the guide- wheels, etc., to the opposite end of the plates. To adapt the Indicator to any pressure, springs are made of the following scales : N'os.— 8 12 16 20 24 30 40 50 60 80 100 Lbs.— 24 36 48 60 70 90 120 150 180 240 300 The number of the spring represents the pounds per square inch required to compress it sufficiently to move the pencil vertically one inch on the diagram. The figures in the lower line designate the maximum pressure of steam or steam and vacuum, w^hich, together with space allowed at each end of stroke for adjust- ment, equals the whole distance which the pen- cil can travel. THE STEAM EXGIXE IXDICATOR. 15 WHAT CAN BE ASCERTAINED BY THE USE OF THIS INDICATOR. First. Whether the steam passages from the boiler to the cylinder are of sufficient size to supply steam in time to produce the best re- sults ; and what proportion of the boiler pres- sure is utilized. Second. Whether the discharge passages from the cylinder are of sufficient size to relieve properlj^ ; and, if not, how much remains as counter-pressure . Tliivd. Whether the piston is properly fitted ; or allows steam to escape into the .exhaust. Fourth. What pressure of steam there is on the piston at every position in the cylinder ; as well as its averao:e. Fifth. At what point in the stroke, and at what pressure the steam is cut oflf ; and whether it is cut oft' sharply or is wire-drawn. Sixth. At what pressure the steam is finally released. Seventh. How soon in the stroke the high- est pressure is reached : and how well main- tained. 16 THE STEAM ENGINE INDICATOR. EigMli, The amount of vacuum acting upon the piston of a condensing engine at every point in the stroke ; and its average. Ninth. Whether there is any compression of the steam remaining in the cylinder before the stroke commences ; and, if so, where it be- gins and how high it rises. Tenth, The actual consumption of steam in giving motion to the engine alone ; and also what additional steam is used in giving motion to the shafting or the machinery at- tached. Eleventh. Where power is sold, how much each tenant consumes ; and in large establish- ments, where friction of shafting and machinery forms a large proportion of the resistance oflered, it guides in the selection of proper lubricants. Tivelfth. The economy of using high pres- sure steam and expansion; and the relative efficiency of the different apparatus for procur- ing expansion. Thirteenth. The quantity of water that would under given circumstances be most economically used in the condensation of the steam, if attached to the air-pump of condens- ing engines. THE STEAM ENGINE INDICATOR. 17 Fourteenth, The accuracy of the steam gage when applied correspondingly. Fifteenth. Whether the valves are properly adjusted and in good condition or not. DIRECTIONS FOR USING THE CROSBY INDICATOR. Hoio to Attach it, — The Indicator should be connected as closely to the cylinder of the engine as possible, as pressure is lost by the use of pipes. The connection may be made by drilling the cylinder or its heads ; but care should be used in drilling the cylinder that the piston does not cover the hole when at the end of the stroke. By allowing a small quantity of steam to enter the cylinder as the drill begins to go through, all chips will be blown out. Xo lead or putty should be used in making the connections. Keep clear of the thoroughfares, as steam passing the hole for the connection reduces the pressiu^e in the Indicator; screw the stop-cock to its place, then open it and blow steam through to clear the connections, and attach the In- 18 THE STEAM ENGINE INDICATOR. dicator by means of the union nut, when in the best position to operate ; move the ad- justable guide wheels to the best position for receiving the cord, and then connect the cord to the apparatus for transmitting the motion from the engine to the paper. The cord must be connected with some part of the engine having a movement co-incident with the piston, and which would give the paper cylinder a movement of about three-fourths of a revolu- tion ; it will frequently be found necessary to erect a temporary rocker-shaft, or lever con- necting with the cross-head, for reducing the motion ; for a beam-engine, a point on the parallel bar, beam, or beam-centre will answer. Beyond these suggestions, the ingenuity and judgment of the operator must determine what is required to produce the proper movement. Care should be taken that the cord be so led off from the part which gives it motion that when the engine is on half-stroke it will be at right angles to such part ; but between the first pulley and the Indicator it may take any required direction. Use as few pulleys and as short a cord as possible. It is also necessary that the length of the cord be easily adjusted and readily connected and discon- THE STEAM ENGINE INDICATOR. 19 nected. To meet these requirements, one end should be provided with a running loop and hook (see cut No. 3) . Arrange the motion of the No. 3. paper cylinder, hv means of the running loop, so that it shall not be checked at one end of the stroke by the stop fixture, and thereby slacken the cord ; nor at the other end by the springs for holding the paper on the cylinder, coming in contact with the pencil ; either of which would render the diagram useless. HoiD to take a Diagram. — Remove the paper cylinder from the drum and place the paper upon it ; the easiest method of doing this is to secure the two lower corners of the paper be- tween the thumb and finger, then put the loop so made over the top of the cylinder ; slip the edges under the springs and slide the whole down to the bottom, leaving it smooth and tight. Instead of the ordinary springs for holding the paper upon the cylinder, a hinged snap- lever supplied with pins and corresponding pin 20 THE STEAM ENGINE INDICATOR. holes, can be furnished when desired. (See Appendix.) This facilitates the placing of the paper upon the cylinder, and keeps it perfectly tight and smooth. Eeturn the cjdinder to the drum ; adjust the cylinder to the pencil for a hair line ; open the stop-cock and allow the steam to enter, heat and expand the cylinder to give freedom of motion, then turn the T handle of the cock- plug to a horizontal position to allow of atmospheric pressure under the piston as well as above it ; connect the cord and draw the atmospheric line ; then turn the T handle to a vertical position and press the paper cylinder up to the pencil, by means of the handle P, long enough for the engine to make one revolu- tion. No nicety is required in this, as the adjustable stop determines the distance moved and delicacy of the lines drawn. The engine should be allowed to run a short time before taking diagrams, to clear the cylinder from water and thoroughly heat it. If it is a new Indicator allow its piston to work for a few moments before taking a diagram. After a diagram is taken, disconnect the cord by means of the hook and close the stop-cock, as continual working only wears out THE STEAM ENGINE INDICATOR. 21 the instrument needlessly. Remove the paper and make the proper memoranda upon the back at once; this should at least include the follow- ing particulars, viz., description of engine; scale or spring ; diameter of cylinder and piston- rod ; which end of cylinder ; length of stroke ; number ofrevolutions per minute ; cubic contents of clearance and thoroughfares ; pressure of steam in the boiler ; and, if a condensing engine, the vacuum indicated by the gage. As many more particulars and circumstances should be added as can be readily ascertained ; among which it is well to include the length of con- necting-rod and the weight of all the recipro- cating parts. To avoid mistakes, designate the two ends of the cvlinder as out-end and craiik-end, Hoiv to take apart and clean it. — Immedi- ately after using the Indicator it should be properly cleaned and oiled. This is done b}^ disconnecting the short lever at the points B and C ; then unscrew the cap or head of the cylinder and carefully remove the piston and spring ; empty the cylinder of water and clean and dry all the parts ; lubricate the cylinder, joints and journals, with a very small quantity of oil, which must be free from all impurities — 22 THE STEAM ENGINE INDICATOR. porpoise or watch oil is the best ; never unscrew the rod from the piston. If the inner surface of the cylinder or the piston should get scratched by any means (and it will be detected by the unsteady lines of the diagram) it should be remedied at once, and in this manner : When the instrument is apart, cleaned and oiled, the piston may be replaced in the cylinder without the spring ; screw on the cap or cylinder-head for a guide and then revolve the piston-rod between the thumb and finger, at the same time moving it up and down ; remove it occasionally and wipe all the parts clean ; after a few opera- tions the surfaces will wear themselves smooth. No grinding or polishing should ever be resorted to. When the parts are clean and the cylinder plumb, the piston, with spring removed, should move freely and uniformly, but slowly, through the whole length of the stroke, with the levers attached and the cock closed ; with the cock open it should drop freely from any position. In putting the parts together the levers and standards should be tested to see if they move freely of their own weight and without side motion in the joints ; then securely screw the spring to the piston and cap. Care should be taken that the slot in the head of the piston- THE STEAM ENGINE INDICATOR. 23 rod is in line with the lever when making con- nection, otherwise it would bind and cause friction. ^ DIAGRAMS. It must always be remembered that the Indi- cator's oflSce is only to represent the pressure on the piston at each point of the stroke, by lines circumscribed upon paper. The correct reading of these lines is left entirely to the operator. For the mere purpose of ascertain- ing the condition of the valves, piston, etc., it will be quite sufficient to scan the outlines of the diagram; but if the power of the engine is required, the mean pressures upon the opposite sides of the piston must be ascertained by meas- urement. In using a graphite wire for marking the lines, any paper susceptible of taking a line impression from an ordinary lead pencil will answer, but if the metallic point is used, a paper expressly prepared for the purpose is necessary, and will be furnished upon applica- tion. The impression in this instance is indelil)le. Diagrams should be taken from both ends of the cylinder, and simultaneously, if practicable ; and the mean result of the two taken as a basis for estimating the power of the engine. The common idea that if the valves are 24 THE STEAM ENGINE INDICATOR. properly adjusted, two diagrams thus taken must be alike, is a mistake. They will in some respects be dissin^lar, from various causes, one of wiiich is the difference in the speed of the piston at opposite ends of the stroke. (See Diag. 9.) There may be a differ- ence also in the size of the thoroughfares. The extreme ends of the diagram are produced at the exact time the engine is passing its centres. In diagrams of non-condensing engines, the lower line is usually drawn slightly above the atmospheric pressure (see Diag. 1) ; while in condensing engines it approximates more or less to that of perfect vacuum (see Diags. 8 and 9) . EXPLANATION OF LINES OF DIAGRAMS. For convenience in describino^ diao;rams their several parts will be described as follows : Atmospheric Line, AA. Clearance Ijine, AB. Boiler Pressure Line, BP. Admission Line, , . HC. Steam Line, CD. Point of Cut-off, D. Expansion Curve, DE. Point of Exhaust, E. Exhaust Line EF. Counter Piessu.re Line, EG. Compression Curve, GH. Vacuum J.ine YY. Theoretic Curve, . . . . . Dotted Line. (See Diag. 1.) THE STEAM ENGINE INDICATOR. 25 In condensino' eno-ines consider line EFG as all exhaust. Different eno-ines oive different diao-rams, and diaoTams taken from the same eno-ine under different circumstances differ. On account of the diversity of style of engines, and the attend- ing variety of circumstances and surroundings, no design for a perfect diagram will answer for more than one particular engine,' and then only with one particular combination of conditions, as every change, whether of speed, pressure, friction, work, etc., produces different results. The important thing always is to procure the greatest mean effective pressure with the lowest terminal pressure. But a few general rules may apply. By taking the different lines drawn bj^ the Indicator, in succession, commencing with the stroke, Ihe main features of merit or defect may be pointed out. For convenience to the beginner, however, all the lines of the Diagram will be noticed and explained in the usual order of production. The A.t7nosj}]ieric Line is traced wlien the atmosphere has free access to both sides of the piston of the Indicator before steam is admitted, and indicates the line of atmospheric pressure, or zero, on the steam gage. The following 26 THE STEAM EXGINE I^^DICATOR. lines are automatically traced by the Indicator and are described as follows : The Admission Line represents the rise of pressure due to the admission of steam to the cylinder. If it is at right angles to the atmospheric line, and is not curved or inclined forwards where conjoining with the steam line, it indicates that full pressure is exerted upon the piston at the commencement of the stroke, caused either by the quick entrance of steam, or by compression, or by both combined. Should this line incline forwards and form a curve in connecting with the steam line, the reverse is indicated ; or should this line continue ver- tically beyond, and then suddenly drop to the level of the steam line, it signifies that the steam is wire-drawn and cannot enter the cylinder with freedom sufficient to keep up the full pressure as the piston starts forward ; but should this line, after projecting above, be suddenly depressed below the level of the steam line, vibrating back and forth one or more times on the latter line with acute angles of return, it may be attributed to the momen- tum of the reciprocating parts of the Indi- cator while running at very high speed. (See Diag. 7.) THE STEAM ENGINE INDICATOR. 27 The Steam Line represents the pressure of the steam upon the piston and its duration^ while acting directly, that is, being constantly- reinforced, from the boiler ; and shows what proportion of boiler pressure is attained, and how soon, and how well maintained. Should this line dip below a horizontal (see Diag. 5) it is an indication of either wire-drawing of the steam somewhere between the boiler and the cylinder, or loss of steam from some cause ^ such as leakage around the piston, or conden- sation of steam on entering the cylinder from loss of heat by radiation and condensation, in- ternal and external. It also shows at its ter- mination the point at which the valve closes or steam is cut off. The TJxioansion Line commences at the point of cut-off wdiere the steam line ends, and rep- resents the fall of the pressure due to the expansion of steam remaining in the cylinder after cut-off. The nearer this line corresponds to the theoretic expansion curve the better, but it generally runs somewhat above, as the pis- ton continues on its course. This is caused partly by leakage of the valve. Should this line, after falling considerably, begin to rise again, and show before the termination of the 28 THE STEAM ENGINE INDICATOR. stroke a pressure in excess of what it did at some preceding point, it indicates that re- ^yaporation of the moist steam has taken place. The heat for this purpose is supplied by the surfaces of the cylinder and piston in contact with the steam, and must he regained at the lieo'innino' of the next stroke from the direct steam. The excess or rise of the line measures the heat lost in the process. Where the ex- jDansion curye intersects the steam line, there is the point of cut-off; it is clearly defined where the yalye closes quickly (see Diag. 4), but where it closes slowly it is more difficult to locate ; in the latter case, take the point on the curyature where it chanoes from conyex to concaye, and through it extend the expansion <3urye upwards by the eye until it cuts the steam line ; the point of intersection is the apparent cut-off. (See Diag. 1.) Should the expansion line drop below the true curye, it indicates, in a non-condensing engine, that the piston leaks, or that condensation has taken place ; in a condensing engine, that either the piston or the exhaust yalye leaks. Should this line fall below the atmospheric line (see Diag. 3), the area thus enclosed should be measured and deducted from the impelling THE STEAM ENGINE IXDICATOR. 29 pressure, as it represents counter-pressure or power lost. The steam may be cut off so early that ex- pansion cannot be advantageously employed even with the highest pressure. If this line is loavy^ consequent upon extreme speed andpres- sure and the use of a spring worked at its^ utmost capacity, or should the pencil describe several diaoTams before removal, the averaa^e or mean should be ascertained. The Exhaust Line commences where the ex- pansion line ends, and is traced while the excess of pressure remaining at the point of exhaust is being released. It indicates whether the ex-^ haust valve opens properly or not, and whether the exhaust port and passages are of sufficient size for the free exit of the steam. 27^6 Line of Counter-pressure in a non-con- densing engine represents by its distance above the atmospheric line the pressure in front of the piston during the return stroke. (See Diag. 1.) Its presence, to any considerable degree, indicates one or more defects, such as smallness^ of exhaust port or pipes, leakage of piston or valves, etc. In a condensing engine it indicates by its distance below the atmospheric line the amount of vacuum existing under the 30 THE STEAM ENGINE INDICATOR. piston at eveiy point of the return stroke, lio^v quickly produced, and how well main- tained ; the efficiency of the condenser, air pump and exhaust valye. (See Diags. 8 and 9.) The Comjpression Line^ when it exists, rep- resents the rise of pressure due to the compres- sion of the steam shut in the cylinder by closure of the exhaust, and indicates the point on the return stroke at which the exhaust-valve closed and compression commenced, and the amount of pressure resisting the movement of the piston as it nears the end of the stroke. (See Diags. 1, 4 and 6.) This pressure is called "cushion- ing," and should be calculated and deducted from the impelling pressure. Should this line be projected above the boiler-pressure, then sud- denl}^ drop in nearly a perpendicular line to the level of the steam line, thus forming a loop, it indicates an excess of "compression, due to closing the exhaust too soon. The remaining lines are drawn by the oper- ator, and are described as follows : Boiler Pressure Line is drawn when the engine is blocked so that the full pressure on the boiler can act upon the Indicator, thereby testing the steam gage, or it may be drawn by scale, at a distance from the atmospheric line THE STEAM EXGIXE INDICATOR. 31 equal to the pounds pressure per square inch as shown by the steam o*ao'e, if this is known to be correct. This line shows by comparison with the steam line the amount of pressure in boiler not utilized by the engine. The Vacuum Line is laid down by scale, usually 15. pounds below the atmospheric line, but 14.7' is nearer correct, and rep- resents perfect yacuum or absence of all pressure. The Clearance Line is laid ojff a certain dis- tance from the steam end of the diaoram, which distance is to the whole leno*th of the diaOTam as the total yolume of clearance, including ports, is to the piston displacement. It represents the waste room between the cut-off yalye and piston when the latter is at this end of the stroke, and is found by either calculating or actually measuring' by water the cubic inches contained in the space between the piston and coyer when the eno-ine is on its centre, and that of the ports and passage ways back to the yalye ; diyide by this the solid contents of that portion of the cylinder occupied by the stroke of piston, and the quotient will represent the denominator of a fraction, which with one for a numerator will giye the pro- 32 .THE STEAM ENGINE INDICATOR. portional part of the length of the diagram to be added to the steam end thereof. (See Fig. 1 . ) Through the point thus formed draw a line at right angles to the atmospheric line. When the clearance is taken into account, this space must be reckoned as part of the diagram in cal- culating the average pressure, and in producing the theoretic curve, or line of perfect expansion. The Theoretic Curve represents the line of true expansion, or isothermal line, and shows by comparison with the line of expansion drawn by the Indicator the degree of excellence at- tained in regard to the construction, adjustment and working of valves, fitting of piston, pro- tection of the cylinder and efficiency of appa- ratus for procuring expansion. According to the law of expansion, if a perfect gas enters freely to tlie cylinder while the pis- ton is travelling a distance equal to one of the above divisions (see Diag. 2) , and is then cut off and the piston continues onto the next division, supposing the gas to remain at the same tem- perature, the pressure is reduced one-half; con- tinue the piston to the third and it will be reduced to one-third ; if to the fourth^ to one- fourth ; and so on to the end of the stroke. This line should always be drawn after the THE STEAM ENGINE INDICATOR. 33 diagram is taken, so that the expansion line actually produced may be compared therewith. If the valves are properly constructed and ad- justed, the piston properly fitted, and the cylinder sufficiently protected, or jacketed, these two curves should nearly coincide, the nearer the better. The true curve commences on the steam line at the point of cut-off, and terminates at the end of the stroke. It may be ascertained in the following manner : Let an area be supposed (seeDiag, 2) whose length represents the stroke of the engine and clearance, and whose breadth represents ninety pounds of steam pressure above the atmosphere, scale forty pounds to the inch. Draw the line of perfect vacuum W ; divide the whole area into any number of equal divisions, by drawing lines (ordinates) at right angles to the vacuum line, and have one of these lines pass through the point of cut-off; numl)er these lines in the direction of stroke, 1, 2, 3, 4, etc. Take the number of the line at the point of cut-off for a numerator and the number of the next line for a denominator, and this fraction will, by measuring from the vacuum line, determine the point on this next line, through which the theoretic curve passes. Continue in this 34 THE STEAM ENGINE INDICATOR. way through the whole number of lines ; then connect these points by lines drawn suffi- ciently curved to make the whole curve regular. The result is the theoretic curve. The ^freater number of divisions the more perfect the curve will be ; but ten is generally sufficient for ordi- nary purposes. Should difficulty occur in ascertaining a distance which will enter into both divisions without a remainder, divide the steam line from clearance to the point of cut- off, into equal spaces ; then continue with these spaces through the remaining division, even should they project beyond the diagram, as the terminal pressure can be measured where the curve crosses the line desiofnatino- the ter- mination of the diaoram. TO COMPUTE THE AVERAGE PRESSURES. Divide the diagram into a number of equal spaces by lines drawn at right angles to the atmospheric line ; ten is usually sufficient, but twenty is l>etter if great accuracy is required. (We furnish, when requested, a convenient instrument for this purpose, i.e., a propor- THE STEAM ENGINE INDICATOR. 35 tional divider, which with a small tiy-square answers every purpose.) In non-condensing engines^ when calculating the average pressure on the steam side of the piston for the whole stroke, the mean pressure in each division or space enclosed by these lines, between the upper line (steam and expansion) and the atmospheric line, should be first ascer- tained. This may be done either by carefully measuring each space between the atmospheric line and the upper line of the diagram, by tl/e scale corresponding to the spring used in the instrument, and the sum of these measurements divided by the number of spaces gives the aver- age pressure per square inch upon the work- ing side of the piston, or average impelling pressure for the whole stroke ; or upon meas- uring the spaces with a common ride, divide their sum by the number of spaces, and multiply the quotient l)y the number of the spring, and the result is the same. Proceed in like manner to find the average resisting pressure upon the opposite side of the piston, measuring the distance in each space l)etween the lower line (counter-pressure and compres- sion) and the atmospheric line ; the difference between the average impelling pressure and the 36 THE STEAM ENGINE INDICATOK. average resisting pressure gives the mean effect- ive pressure exerted. (See examples.) Shovild the expansion line fall below the atmospheric line, the area of the loop thus formed should be measured in like manner, and deducted the same as the compression and counter-pressure. If the diagram is also divided by lines drawn parallel to the atmospheric line, into equal spaces and corresponding to a certain number of pounds pressure, say five pounds, as per scale, beginning at vacuum, the operator is enabled readily to read the general charac- teristics by sight. A very simple method of measurinof diaorams has been suo'o-ested which is much easier than either of the above, and reduces liability of error. Take a nar- row strip of paper which has a straight edge, place it across the diagram, and let one end of this strip come directly over the atmospheric line ; then with a knife blade or sharp pencil mark the length of the first space as determined by the steam line ; then move the paper along to the next space, placing the mark made by the pencil over the atmospheric line ; then make another mark at the point where it crosses the steam or expansion line, whichever it may be, being careful always to take a point THE STEAM ENGINE INDICATOR. 37 on the upper line, which shall represent the mean length as nearly as possible ; so proceed until the length of each space has been added to the first ; then measure with a rule from the end of the paper to the last pencil mark, divide this by the number of spaces to get the average length, and multiply the quotient by the number of the spring in use, and the result is the aver- age impelling pressure per square inch. Pro- ceed in like manner to measure the average resisting pressure, etc. Ten is the usual number of spaces used, but for exactness tT\^enty is better. In condensing engines it is usual to find the value of the steam and vacuum pressures separately. To do this, measure from the atmospheric line upiuards for steam, as be- fore, and downwards to the exhaust line for vacuum. In calculating the average pres- sures of each, proceed in the same manner described for non-condensing engines, not forgetting the remark concerning the de- duction necessary should the expansion line drop below the atmospheric line before the completion of the stroke. The sum of these average pressures is the mean effective pres- 38 THE STEAM ENGINE INDICATOR. sure exerted. Draw the line of perfect vacuum at the bottom, measuring hy scale from the atmospheric line ; for greater accuracy and to ascertain the duty performed by the condenser and air-pump this should be determined by the barometer, as the pressure of the atmosphere varies according to its density. In lieu of measuring Diagrams from the atmospheric line, as a base, some prefer to use the vacuum line, representing, as it does, the line oi no pressure ; in which case any loop formed by the expansion line dropping below the atmospheric line will necessarily have been included in the resisting pressure, and deducted the same as compression and counter- pressure. A quicker method of ascertaining the effect- ive pressure^ whether in condensing or non- condensing engines, is to measure the spaces between the upper and lower lines of the dia- gram without regard to the atmospheric line, and then proceed in the manner as before stated. (See examples.) This does away with separ- ate measurements, excepting when a loop is formed in non-condensino' enoines. THE STEA31 ENGINE INDICATOR. 39 THE POWER OF THE ENGINE. It is customary to designate the capacity of an engine in "horse-powers" as the units of meas- urement, by which term is understood, power sufficient to raise 33,000 pounds one foot high per minute. Its distinctions are "nominal," " actual " and " effective " horse-power. The first is applied to the size, the second to the power of the steam engine, and the last to the power, less the force, which is required to overcome its own friction, running at the same speed. The friction of the engine alone the Indicator will show by taking a separate dia- gram. (See Diag. 3.) But the increase of fric- tion when resistance is being overcome is not known to any degree of certainty, excepting the fact that it increases as the resistance increases, and is proportionately less as the size of the engine is increased ; and it is generally estimated at five per cent, of the actual power exerted. The actual power is found correctly only by the use of the Indicator, and the eftective power by deducting from the actual power the power required to overcome the friction of the engine alone, together with five per cent, of the actual power for additional friction, created by 40 THE STEAM ENGINE INDICATOR. the increased resistance when loaded. (See Examples.) Initial pressure is the pressure which acts upon the piston at the beginning of the stroke. Terminal pressure applies to exhaust or re- lease pressure that would exist at the end of the stroke, if the steam had not been released earlier. TO CALCULATE THE POWER OF EN- GINES. The mean eflective pressure, multiplied by the number of square inches contained in the piston, and this product multiplied by the mean velocity of the piston in feet per minute, and the result divided by 33,000, gives the actual horse-powers exerted. Another method of cal- culation which commends itself is to multiply the area of the piston in inches by the speed of the piston in feet j^er minute ; divide the pro- duct by 33,000, and the quotient will be the number of horse-powers exerted for each pound of eflFective pressure on the piston ; this multiplied by the average eflective pressure per square inch gives the actual horse-powers of the engine. To obtain the effective power ^ as has been before said, the power required to run the engine alone, ascertained by the Indicator, must be THE STEAM ENGINE INDICATOR. 41 deducted from the actual power, together with five per cent, of the latter for increased friction when overcoming resistance occasioned by the load. (See Examples.) To ascertain the precise area of the piston that is acted upon by pressure, the cross-sec- tional area of piston-rod should be deducted from the side to which it is attached or one- half from the mean. Ordinarily an eno-ine will o-ive the same dia- gram at each successive revolution, unless the resistance should vary, but should several lines be drawn their mean should be taken as the proper diagram. In ascertaining the power requisite to o^'^rcome different resistances, it is better that the speed of the engine should be the same in each case. If the Indicator is used on a locomotive, the grade, curve, weight of train and diameter of the driving-wheels should be taken into account in certain calculations. TO MEASURE THE QUANTITY OF STEAM CONSUMED IN THE CYLINDER. Add to the diagram the clearance ; multiply the pressure in the cylinder (measuring from 42 THE STEAM ENGINE INDICATOR. the line of perfect vacuum) at the point in the stroke where the steam is released, by the area of the piston in square inches, and the product by that part of the length of s.troke, measured in inches, from the clear- ance line to the point of release. Multiply this result by the number of strokes per hour ; reduce the cubic inches to cubic feet. Multiply this by the weight of a cubic foot of steam at the pressure at release ; from which subtract the quantity of steam shut in by compression, ascer- tained in like manner, for the pressure and part of stroke, and the difference will be the pounds of water used per hour, passing through the cylinder in the shape of working steam. While the Indicator Diagram, taken as an ex- ponent of the steam engine, furnishes facts which could not otherwise be ascertained, among others, the amount of steam consumed in the cylinder as working material, it does not indicate the amount actually furnished by the boiler. This is only ascertained by actual measurement of water evaporated, and is in excess ; the difference measures the loss from leakage, prim- ing, blow-off, radiation and conduction and en- trained water (of which priming is an extreme degree), and cannot be debited to the engine. EXAMPLES Compute the Mean Effective Pressure, Actual and Eff^ective Horse-powers, from Dlagravis Nos, 3 and 4. MEASUBED BY SCALE IN POUNDS. From the sura of impelling pressures in spaces, 290 lbs. Deduct the sum of resisting pressures in spaces, 10 '' Divide the remainder by number of spaces, 10)280 Result, mean effective pressure, 28 OR, MEASURED BY RUUE IX INCHES. From the sum of distances from atmospheric line to upper lines, 7.25 Deduct the sum of distances from atmospheric line to lower lines, .25 Divide the remainder by number of spaces, 10)7.00 Multiply the quotient, .7 By the number of spring, 40 Result, mean effective pressure, 28 OR, MEASURED WITHOUT REGARD TO ATMOSPHERIC LINE. In pounds per scale, = 280 -^ 10 = 28 = mean effective pressure. In inches by rule = 7 -r- 10 = .7 X 40 = 28 = mean effect- ive pressure. Multiply the mean effective pressure in lbs., 2S By area of piston in inches, 50.26 Multiply this product, 1407.2S By the speed of the piston in feet per minute, oGO Divide this result by 33000 )506620.80 The quotient is the actual horse-powers exerted, 15.352 Or, multiply area of piston in inches, 50.26 By speed of piston in feet per minute, 360 Divide the product by 33000) 18093.60 Which gives the horse-powers exerted per each lb. mean effective pressure, .548^^ Multiply this by the mean effective pressure, 28 For the actual Horse-powers exerted, 15.3524 From which deduct the power required to run engine alone, .24 And 5% for increased friction when loaded, .76 1 Result effective horse-powers of engine, 14.3524 44 EXAMPLES. Cornpute the Mean Effective Pressure, Actual and Effective Horse-powers, from Diagram No. 8. MEASURED BY SCALE IN POUNDS. To the sum of pressures above atmospheric line, 84 lbs. Add the sum of pressures below atmospheric line, 120 " Divide this sum by the number of spaces, 10)204 '^ The result is the mean effective pressure, 20.4 ^' OE, MEASURED BY RULE IN INCHES. To the sum of distances from atmospheric line to upper lines, 7 inches Add the sum of distances from atmospheric line to lower lines, JjO ^' Divide this sum by the number of spaces, 10)17 " Multiply the quotient, 1.7 '^ By the number of the spring, 12 '' The result is the mean effective pressure, 20.4 *' OR, MEASURED WITHOUT REGARD TO ATMOSPHERIC LINE. In pounds per scale = 204 -4- 10 = 20.4 = mean effective pressure. In inches by rule = 17 -^ 10 = 1.7 X 12 = 20.4 = mean effective pressure. JVIultiply the mean effective pressure in lbs,, 20.4 By area of piston in inches, 7088.24 Multiply this product, 144600.096 By the speed of piston in feet per minute, 300 Divide this result by 3300 0)4.3380028.8 The quotient is the actual horse-powers exerted, 1314.546 Or, multiply area of piston in inches, 7088.24 By speed of piston in feet per minute, 300 Divide product by 33000) 2126472 "Which gives the horse-powers exerted per each lb. of mean effective pressure, 64.4385 Multiply this by mean effective pressure, 20.4 For the actual horse-powers exerted, 1314.5454 From which deduct the power required to run engine alone, about H%, say 20.0 And 5% for increased friction when loaded, 65.7 85.7 Kesult, effective horse-powers of engine, 1228.8454 THE STEAM ENGINE INDICATOK. 45 DIAGRAM No. 1. 46 THE STEAM ENGINE INDICATOR. DIAGRAM No. 2, ^ > ^^^■■L ■■■■1 < > THE STEAM ENGINE INDICATOR, 47 DIAGRAM No. 3. 48 THE STEAM ENGINE INDICATOR, DIAGRAM No. 4. THE STEAM ENGINE INDICATOR. 4^ DIAGRAM No. 5 50 THE STEAM ENGINE INDICATOR. DIAGRAM No. 6. THE STEAM ENGINE INDICATOR. 51 DIAGRAM No. 7. 52 THE STEAM ENGINE INDICATOR, DIAGRAM No. 8. Cylinder 95x120. 15 revolutions. 12 scale. Low Pressure Condensing. Crosby Indicator. THE STEAM ENGINE INDICATOK DIAGRAM No. 9. 53 CROSBY STEAM GAGE AND VALYE COMPANY. J. H. MiLLETT, President. Geo. H. Crosby, Superinteuueni, Geo. H. Eager, Treasurer. Sole Proprietors and Manufacturers of the iEtill Adjustable Pop Safety Valve, Steam Pressure Gage, Safety Water Gage, Automatic Reducing Valve, Steam Engine Inaicator. Sole Manufacturers and General Agents of THE "VICTORY" Steam Cylinder Lubricator, KEYES' SELF-TESTING PEESSUKE GAGE. Manufacturers of Steam Pressure and Vacuum Gages ^vith Bourdon Spring, Engine Revolution Counters, Marme Clocks, Hydraulic Gages, Test Gages, Test Pumps, Water Gages, Gage Cocks, Whistles, Pyrometers, Sah- nometers. Thermometers, etc., AND ALL INSTRUMENTS Incidental to the use of Sieana Engines and Boilers. DEALERS IN SCOTCH AND AMERICAN GLASS TUBES, And Steam Fittings of Every Description. COR. MILK AND BATTERYMARCH STS„ BOSTON, MASS. SEND FOR n.I.USTRATED CATALOGUE. 56 ArPENDIX Interior View. Bourdon Pressure and Vacuum Gages. This style of Gage is better adapted for indicating low pressures and vacuums than any other known, and is fully warranted for such uses. The pressure required should be stated in ordering gages. SIZES. No. 0, Brass Case and Ring, - - - 1, 2, 3, I 7. 2y2, 10, Iron Case, Brass Ring, Spun 10 in . Dial - SVs (( 6% tt - 6 n bK it - 41^ ft 3y> (t - 2V2 tt ^V2 tt - C3/4 tt (') (t - .^>y2 tt 4V2 tt - r.i/o irass Ring, - - - "> '* Cases made with Deep Hkass Cases or Octago.n Fackd Rings when ordered. All Gages are graduated and tested by an open mercury column, and warranted cofect. m^^A Siphon is indispensable for every Steam Gage, and none war- ranted without it. SEND FOR ILLUSTRATED CATALOGUE. APPENDIX , 57 Interior VrEW. Crosby's Improved Steam Gages. The hollow spring in this Gage is so shaped and arranged, and the mechanism is such, that the vertical as well as the horizontal movement of its free ends is fully utilized. It thereby permits the use of springs 100 per cent, stronger than can be used in any other gage, so presenting its setting under any pressure which may he indicated upon its dial. While this Gage is especially adapted for high pressures, it is as sensitive as the Bourdon Gage. No vibration of the pointer. No Freezing. ^ SIZES. No. 0, Brass Case and Ring, - - - - i« 2 «. « « f( 2* •* ** ** - - - - « ^^ it u " . , - - (( 5' « «< «<_.-- No. 1 V2, Iron Case, Brass Ring, - - - - u 21/2. '* " . - . - « 01/ it »< . - - . " 4: " ...--- u 51/ it *« _ _ - ^ *^^ Gages marked to any pressure not exceeding 500 lbs. per square inch. m^ A Siphon is indispensable for every Steam Gage— and none warranted without it. ■, ^s^a All Gages are graduated and tested by an open mercury column ana warranted correct. „. , „ o„„« A maximum pointer can be attached to any High-Pressure Gage. SEND FOR ILLUSTRATED CATALOGUE. 10 in SV2 6% 6 6 51/2 Dial. tt (( (( tt it ii a it n 58 APPENDIX. Crosby's Improved Hydraulic Gages. To sustain witli safety the enormous pressure to which these gages are subjected, a hollow steel spring, bent ac- cording to the Crosby Improved pattern, hardened and carefully drawn to spring temper, is substituted for the ordinary gage spring. In ordering, the maximum pressure to which they will be subjected should be stated ; and if the Tons on a Ram are required to be show^n on a second grad- uated circle, the diameter of the ram should also be given. No extra charge for second circle. Gages can be marked up to 20,000 lbs. per square inch, and warranted to stand any pressure indicated upon the dial. SIZES. No. 1, Brass Case, 814 in. Dial, it 2, «' " 6% ♦* 3, " " 6 " " IV2, Iron '* 81/2 '' *' 21/2, " " 63/4 " " 31/2, *' •* 6 1000 to 16,000 lbs. 1000 " 10,000 " 1000 ♦' 6,000 " 1000 " 16,000 '* 1000 " 10,000 " 1000 *• 6,000 " These Gages are only made to order. Combination Pressure Gages. WE MANUFACTURE SEVERAL KINDS, AS FOLLOWS: — For Water Works. Graduated for pounds pressure per square inch and height of water in feet. — For Condensers. Graduated for pounds pressure per square inch and Vacuum in inches. — For Dentists, etc. Graduated for pounds pressure per square inch and Degrees of Heat. Sizes as per page 56. Test Gages. These Gages are highly finished in every particular. The movements are accurately adjusted and work smoothly. The dials are graduated in pound marks, tested by an open mercury column, and every instrument is fully war- ranted. Sizes as per page 56. SEND FOR ILLUSTRATED CATALOGUE. APPENDIX. 59 CROSBY'S ADJUSTABLE POP SAFETY VALVE. One of the prime causes of boiler explosions is the gradual and insidious increase of the pressure of steam beyond the endurance of the boiler; but to every boiler there is a limit of pressure within which it is substantially safe. This point should be ascertained by hydraulic test annually, and no excess of pressure beyond this limit should be allowed at any time. The only sure pr(ventive is a safety valve which is all its name implies. The diameter of a safety valve is not an infallible test of its efficiency. A valve is effective in direct proportion to its lift, other conditions being equal. The higher the i^ressure of the steam, the less will a common safety valve lift; at most, its lift is very slight; and under its own action, with the increasing pressure of steam it will not increase suffi- ciently to relieve the boiler under all circumstances; but the pressure can .and may increase until an explosion occurs, while the valve is in operation. The co:nmon safety valve has much to answer for. Owing to the great friction of its parts, it will not open until the prtsfiure is above what it is set at; it will continue to blow a 'fer the pressure of the steam has fallen far below the point of opening; it wastes large quantities of valuable steam in operation. There are other grave faults, but these stated are sufficient to condemn it. Instead of standing guard over the boiler, a sentry has to be set over it, and sliould li«, by accident, ignorance or negligence, not properly attend to his duties, as is so often the case, especially in the use of portable boilers, the boiler is Avithout any safeguar.l what- ever. Hence the importance of any device which sUall re- duce the danger to its minimum. A safety valve which is automatic, certain in its action, prompt in opening and closing at the required points of pressure, and can be fully relied upon to relieve the boiler under all circumstances, is what is necessary. SEND FOR ILLUSTRATED CATALOGUE. 60 APPENDIX. THE CROSBY Adjustable Fop Safety Valve, Affords all these qualities^ and experience and use have confirmed the following claims for it, namely : — 1st — Opens precisely at fixed working pressure. 2d — Discharges all excess of steam above fixed working pressure. 3d — Reduces the pressure rapidly upon opening. 4th — Closes with the least possible loss of steam. 6th — The limits of pressure within which the valve will open and close are adjustable, 6th — Uniform in action at different pressures. 7th — Simple in arrangement and easily connected and ad- justed. 8th — ^Does not deteriorate under continued use. 9th — ^Never sticks on seat. 10th — Makes comparatively little noise in discharging. 11 th — Occupies less room than any other safety valve. SIZES. 2 *i 2V4 2% ft ft 3 ft 1*A tt ft ft 2 ft 2V4 (( 2V« (( 3 tf 3% (( 4 <( 5 (( with Iro» Case and Lockup. tt <( tt tt it ft if ft it it it it it tt ^ (( (( (( In ordering state what pressure valves shall be set at. If flange is required, state the diameter. SEND FOR ILLUSTRATED CATALOGUE. APPENDIX, 61 CROSBY'S ADJUSTABLE POP SAFETY VALVE. With Lock-up for Steamboat or Stationary Boilers. SEND FOR ILLUSTRATED CATALOGUE. fe2 APPENDIX. *ii/is£xj. ct/f/ovA^osa/v sa CROSBY'S ADJUSTABLE POP SAFETY VALVE Half -SIZED cut of 2\ inch Locomotive Valve. SEND FOR ILLUSTRATED CATALOGUE. APPENDIX. 63 This cut represents a 2i in. Yalve, as designed for locomotive use, half size. Each of these Yalves is tested under steam pressure, and set to open at the exact point of pressure desired, and is adjusted to close at about two pounds reduction ordinarily ; both of these points can be readily changed by the operator without removing it from the boiler or reducing steam. It is believed any person of ordinary intelligence will readily understand the principle and operation of this Yalve by the following description and explanation: The Yalve proper B B rests upon two flat annular seats Y Y and W W on the same plane, and is held down against the pressure of steam by the steel spiral spring S. The tension of this spring is caused by screwing down the threaded bolt L, at the top of the cylinder K. The area contained between the seats W and Y is what the steam pressure acts upon, ordinarily, to overcome the resist- ance of the spring. The area contained within the smaller seat W W, is not acted upon at all until the Yalve opens. The large seat Y Y is formed on the upper edge of the shell or body of the Yalve A A. The smaller seat W W is formed on the upper edge of a cylindrical chamber or well C C, which is situated in the centre of the shell or body of the Yalve, and is held in its place by four arms D D, radi- ating horizontally at right angles to each other, and connect- ing it with the body or shell of the Yalve. These arms are hollow and form four passages E E, for the escape of the steam or other fluid from the well into the air when the Yalve is open. This well is deepened so as to allow the wings X X of the Yalve proper to project down into it far enough to act as guides. The area of the apertures, at the outer ends of the passages through the arms, is reduced more or less at will, by screwing up or down the adjustable ring G G. SEND FOR ILLUSTRATED CATALOGUE. 64 APPENDIX, Action of the Valve when Working Under Steam. When the pressure under the Valve is within about one pound of the maximum pressure required, the Yalve will open slightly, and the steam will escape under the larger seat into the cylinder surrounding the spring, thence into the air; the steam is also forced mider the smaller seat into the well and thence through the passages in the arms into the air. As soon as the pressure attains the exact maximum point, the Yalve will be lifted so high as to force the steam into the well faster than it can escape through the apertures in the arms; a pressure will then accumulate under the inner seat, which will be in excess of what was required to overcome the increasing resistance offered by the spring, and acting upon the additional area presented, at once forces the Yalve wide open and rapidly relieves the boiler. This pressure under the inner seat is of itself differential. The Yalve then at once slowly settles down and the pres- sure under the inner seat as slowly diminishes, and so con- tinues until the area of the opening under the smaller or inner seat is less than the area of the apertures in the arms for the escape of the steam ; the pressure then ceases and the Yalve promptly closes. The point of opening can be readily changed while under steam by screwing the threaded bolt at the top of the cylinder, either up or down ; and the point of closing is as easily adjusted by screwing up or down the ring surrounding the outside shell or body of the Yalve. The seats of this Yalve are flat and do not wear out and leak so readily as beveled seats. SEND FOR ILLUSTRATED CATALOGUE. APPENDIX. 65 Crosby's Self-Regulating Reducing Valve. This Valve was produced to meet an important want, i. e.y to reduce the pressure of direct steam, gas, or other fluid taken from a boiler or generator, to a lighter pressure in the pipes or apparatus for manufacturing or heating purposes, and maintaining such pressure constantly, not- withstanding the variation that may take place in the boiler above the pressure required. The operator can re- adjust at will by simply turning the screw upwards for in- creased, and downwards for diminished pressure, and a steam gage attached through the nut on top of the valve will indicate the pressure which the valve is supplying. It is adapted for use in Distilleries, Sugar Refineries, Bleacheries, Paper Mills, and for reducing and regulating the pressure of steam supplied from boiler or street mains to dwelling houses, etc., and steam heating in general, or wherever a constant unvarying pressure is required. We make the following claims as to its qualities and capacity, which are being confirmed daily, viz. : 1st. Certainty and nnifonnity of action at different pressures. 2d. Simple in arrangement, easily connected and adjusted. 3d. Compact, occupying no more space than a G-lobe Valve. 4tli. Does not deteriorate under continued use. 5tli. No outside leakage or drip. 6tli. Works without Diaphragm or Rubber. 7th. No Stuffing boxes to take care of. 8th. Costs less than any other Eegulating Valve. SIZES, For 1/^ inch Pipe, i For 2 inch Pipe. (< 8/ (( (( "3 '^ *' " 114 " *' I "5 " " CROSBY STEAM ENGINE INDICATOR. Each Indicator is equipped with one Spring, tscale, Elbow and Cock ; also, two quires of metallic paper, bottle of watch oil, screw-driver and wrench, and is neatly fitted into a velvet-lined walnut case, with nickel handle, hinges, hooks, and lock and key. Directions for using the Indicator and a few general rules for reading and measuring diagrams accompanies the whole. When requested, any extras, such as Proportional Dividers, Telescope-Connection, Carrjdng Pulleys, Clamps, or any extra Springs, Scales, Elbows, Cocks, Paper or Oil, will be furnished as such. N. B. A hinged snap-lever for holding the paper on the cylinder is supplied instead of the ordinary springs for that purpose, when especially ordered. SEND FOR ILLUSTRATED CATALOGUE. 66 APPENDIX. Engine Revolution Counters These instruments are made upon an improved plan, taken from a German device used for another purpose, and are in many respects superior to, and more durable than any other. The mechanism is very simple and will not readily get out of order. The running parts are all made of iron or steel, and so less liable to wear. Every counter fully guaranteed. Sizes as follows : 10 in. Dial, _ _ _ _ - Brass Case and Ring. 81/2 ** ------ *' " " 6% '' ----- '^ «« ii Counter Movement witliout Case, - - 2 in. and 2l^ in. Pedestals furnished when ordered. Marine Clocks. The movements in these Clocks are very superior, are fitted with the Patent Kegulator and Chronometer Balance, are full jewelled and warranted. SIZES, 10 in. Dial, 634 - ^ - 1 or 8 Day. _ _ a Pedestal furnish Cases Fitter! witi 6 in. Dial, - 51/2 - . - - 41/2 " - - ed when ordered. h a Lock and Key, 1 or 8 Day. Test Pumps. SIZES AND STYLES. Small Screw (Inspector's). Large Screw, with stand. Large Lever, with table. Crosby's Safety Water Gage. A very simple device, which does not alter the external appearance of the water gage and enhances its value greatly. Its action is so complete, that upon the sudden breaking of a glass tube not a drop of either steam or water is percepti- ble, other than was in the glass at the moment of breaking. SEND FOR ILLUSTRATED CATALOGUE. APPENDIX. 67 The " Victory'* Lubricator, For Oiling the Valves and Cylinders of Steam Engines. For Effectiveness, Economy and Reliability, this Lubri- cator is without a rival. It embraces the remarkable fea- ture of SIGHT FEEDING, which enables the engineer to set the proper feed at once, relieving him from the necessity of GUESSING the rate at which his lubricator is feeding, or whether it is feeding at all. In this Lubricator the oil is seen passing to the engine in drops, and may be regulated to deliver even less than one drop a minute, while uniform and certain action is still secured. SIZES. Quarter Pint. One Quart. Half Pint. Half Gallon. One Pint. One Gallon. Crosby's Improved Pyrometer. Adapted for Blast Furnaces, Hot Air Pipes, Superheated Steam, Varnish Kettles, Tempering Ovens, Baker's Ovens, Drying and Japan Ovens, Oil and Tar StiUs, Galvanizing Baths, Wire Annealing, Chimneys, etc. This Pyrometer correctly indicates Temperatures to 1200 degrees Fahrenheit by the expansion of its Metallic Stem. Each instrument is carefully graduated to a standard, and is fully warranted to the highest Temperature marked upon its dial. SIZES. Iron Case and Brass Ring. 5 inch Dial, 6 i ' 6% 8% i 5 i 6 t < 63/4 . (( 8y2 < Brass Case and Ring, THERMOMETERS OF ALL KINDS. Salinometers. SEND FOR ILLUSTRATED CATALOGUE. 68 APPENDIX. Crosby^s Low Water Alarm. This instrument works automatically and irresistibly without the use of Fusible Plugs, Floats, Cranks, Springs, or other moving machinery, and no part need be removed or readjusted to fit it for work again after its action. Is simple, reliable, cheap and durable. Open Mercury Columns. Delicately graduated and warranted coiTect, Siphons, for Steam Gages- improved Brass Siphon and Cock combined, non-freezinj ♦' " " without Cock, '• Cocks, for Gages. STYLES, Large and Small Common Cocks, with T handles. Large and Small Union Cocks, Lever or 'J' handles. Gage Cocks. With or ivithout Self Cleaning Attachment. Steam Whistles. STYLES, No. 1, without valve. No. 2, with upright valve. No. 3, with side valve. Chime whistles, of any number or size of Bells required. Whistle Valves. Scotch Glass Tubes American Glass Tubes Any size or length to order. SEND FOR ILLUSTRATED CATALOGUJi APPENDIX. 69 U. S. GOVERNMENT APPROVAL. Our Gages and Yalves have been approv^ed and adopted by the board of U. S. Supervising Inspectors of Steamboats and the Secretar}' of the Treasury. The Committee of U. S. Supervising Inspectors, appointed to test Safety Valves, state in their printed Report to the Board: *' that they have no hesitancy in report- ing THAT AMONG THE VERY EFFICIENT INSTRUMENTS THE Crosby was one of the most efficient;'' and that *' upon the first trials an excess was OBTAINED, BUT THIS WAS ONLY TEMPORARY ; AND UPON A TRIAL AFTER RE-ADJUSTMENT, NO EXCESS WAS OBTAINED." A tabulated report of which is as follows : CO 1o '6 o Q 5 in. 68-2 70 671-2 68 Opened and closed fire times in 1 min. 10 in. 69 70 u ». «. ten ** 10 " *' Movement of Opening and Closing very- clear and points well defined. Actions steady^ Opening promptly. Closing promptly." SEND for illustrated CATALOGUE. INDEX. PAGES, Admission Line .... 15, 24, 26 ^^ ^' Explanation of . 26 Air-pump, Efficiency of . . 16, 29, 30, 38 Appendix 54-70 Atmosphere, Density of . . 38 Atmospheric Pressure . 20, 24, 25, 28, 38 Line . . . . 20, 24, 25, 35, 36, 37, 38 '' '' Explanation of . 25 " '' Measuring from . 31, 35, 36, 37, 38 Average Pressures . . . . 15, 23, 32, 34, 35, 37, 40 To Compute . . 32, 34 Boiler, Steam furnished by . 15, 27, 31, 42 '' Pressure . . . . 15, 21, 27, 30, 31, 42 Line . . . 24, 30, 31, Clearance . . . .21, 24, 31, 32, 33, 34, 41, 42 '* Contents of . 21, 31,*32 ** To be added to Diagram . 31, 32, 33, 34, 41 ** Line . . . . 24, 31, 32, 33, 34, 42 ** " Explanation of . . 31 ^* ^* Measuring from . . 31, 32, 33, 34, 42 Compression . . .15, 16, 24, 26, 30, 35, 36, 38, 42 " Average . . 30,42 " Line . . . . 24, 30, 42 '' '' Explanation of . 30 Cord, Indicator . . . . 10, 11, 12, 18, 19, 20 *' Point on Engine to Connect . . 18 Condenser, Efficiency of . . 16, 29, 30, 38 Counter-pressure . . . . 15, 24, 28, 29, 35, 36, 38 n INDEX. Counter-pressure Line, Explanation Crosby's Improved Indicator . Description of Directions for Using PAGKS. . 29 8, 9, 17 . 8 . 17 . 30 Cushioning, Explanation of . Cut-off, Point of ... . 15, 27, 28, 29, 32, 33, 34 '• Pressure at 15,23,27 Cylinder, Dimensions of Engine .... 21, 31 Diagrams from each end of . . 14, 21, 23, 24 Discharge Passages from . . 15, 24, 29 Drilling and Connecting with . . .17 Indicator .... 10, 13, 20, 21 , 22, 32 Name of ends of 21 Paper ...... 10, 19, 20 Pressure in 5, 14, 15, 16, 20, 23, 25-30, 32, 34-38, 41, 42 Scratches on Indicator Piston or . . . 22 Steam consmned in . . 15, 16, 31, 41, 42 ^* Passages between Boiler and 15, 24, 26, 27 Disideratum, or the important thing . . . .25 Diagrams, 23 '' as Exponents of Steam Engines, 5, 6, 15, 16, 23, 25, 42 Causes which determine figures of 5, 25, 24, 29 Clearance to be added to .31, 32, 33, 34, 41 Divisions or Spaces of . Difference in . Errors in Keading '^ Measuring *^ of Registration on 7, Explanation of Lines of Examples of . Features of Merit or Defect' Form of . Friction .... from each end of Cylinder 33, 34,36, 37, 38 23, 24, 25, 29, 41 5 5, 36 12, 13, 17, 19, 23, 29 24-34 45-53 25-34 . 5, 7, 23, 25 16, 25, 39, 40, 41 . 14, 21, 23, 24 INDEX. Diasrrams, How to take Instrument for Spacing Indicator, Loops on , . . Lines of . . 23, 24-34, Memoranda on Methods of Measuring . 28, 35, 36, *' Names of Lines "" Paper used for '• Reading .... ^' Serrated Lines on . " Upper and Lower Lines of Dividers, Proportional Drum. Indicator .... Errors of Calculation '• Measurement . " Reading .... '* Registration . . .7, Examples of Computation ^' Diagrams . Exhaust Line . . , . . ^' " Exj)lanation of '' Yalve, Condition of 15,17,23, Expansion, Apparatus for Procuring " Economy of . " Law of . '' Line, . . 24, 27 " '^ Explanation of '' " Theoretic Friction Diagrams . '* of Steam Engine Gage, Steam . '' Vacuum Horse-power, Definition of Term '^ see Power of Steam Engine Hook and Running Loop 28, 5,1 24 12,1 27, 28, 32, 111 PAGES. . 19 . 34 23, 25, 42 30, 36, 37, 38 37, 38, 41, 42 . 21 35, 36, 37, 38 . 24 14, 19, 21, 23 . 5, 23, 36 7, 22, 26, 29 35, 36, 37, 38 . 34 10, 12, 19, 20 5 5,36 17, 19, 23, 29 . 43, 44 45-53 24, 29, 37 . 29 29, 30, 32, 33 . 16, 32 . 16 16, 35, 36, 37, 38 . . 27 27, 28, 32, 33 25, 39, 40 25, 39, 40, 41 17, 25, 30, 31 . 21 . 39 . 40 . 19, 20 IV INDEX. PAGES. Improvements in Indicator 6, 7, 8 Indicator, Advantages resulting from Use of 5, 6, 9, 13, 39 " Crosby's Improved . . . . 8, 9, 17 a Cord Condition of . Cylinder, Description of Diagrams, Direct-acting . Directions for Using 10, 11, 12, 18, 19, 20 . 22 10, 13, 20, 21, 22, 32 . 8 23, 25, 42 . 6 . . . 17 Facts Ascertained by Use of 5, 6, 15, 16, 23, 25, 39, 40, 42 For High Speed or Pressure . . . 6, 8, 14 How to Attach . 17 How to Take Apart and Clean '' " "2, Diagram with Improvements ... McNaught's . . . . . 21 . 19 . . 6,^7, 8 . 6 Kichards' .... . 7 Reciprocating Parts of . 6, 7, 12, 13, 26 ** Multiplication of Piston Motion of . 6, 7, 13 '' Oil for Lubricating . . .12, 16, 21, 22 ** On Locomotives 41 ** Original Inventor of 6 " Parallel Motion for .... 7, 8, 13 ** Piston, . . 7, 8, 10, 12, 13, 20, 21, 22, 23, 25 Piston-rod . . . .10, 11, 12, 13, 22 " Self-lubricating .... 11, 12, 13 " Simplicity of Operating Crosby's . . 13, 14 '' Springs . . 6, 7, 10, 11, 12, 19, 21, 22, 29, 35 ^' Superiority of Crosby's . . . . 13, 14 " The Steam Engine . . . . . 5, 6 '' Watt's . . , 6 Introduction, 3 Law of Expansion 32 Lines, Admission 15, 24, 26 INDEX. Lines, Atmospheric . '* Boiler Pressure ** Clearance ^' Counter-pressure " Compression . PAGES. 20, 24, 25, 35, 36, 37, 38 24, 30, 31 24, 31, 32, 33, 34, 42 . 24, 29 24, 30, 42 Errors in Registering, Reading and Measuring 5, 7, 12, 13, 17, 19, 23, 29 Exhaust 24, 29, 37 Expansion . . 24, 27, 28, 32, 33, 35, 36, 37, 38 Explanation of 24-34 m 23, 24 -34, 24. ** Forming Loops ** Features of Merit or Defect '' Hair '^ Indellible " Names of Diagram *' of Diagram . ** Reading Diagram . *^ Serrated '' Steam . *' Theoretic Expansion ^^ Upper and Lower . ** Vacuum *^ Variable or Double '' Wavy . Loops on Diagrams . "" Running Lubi-icating, Oil for Self . McNaught's Indicator Measuring Clearance " Diagrams ** from Vacuum Line ** '^ Atmospheric Line ^^ Steam Consumed in Cylinder Oil for Lubricating . '* Reservoir in Piston-rod 28, 30, 36, 37, 38 25-34 11, 14, 20 . 23 . 24 35, 36, 37,38,41,42 . 5, 23, 36 . 7, 22, 26, 29 26, 27, 33, 34, 35, 36 24, 27, 28, 32, 33 24, 35, 36, 37, 38 ^4, 31, 33, 36, 38, 42 . 29, 41 . 29 28, 30, 36, 37, 38 19, 20 . 12, 16, 21, 22 11, 12, 1:5 ... 6 31, 32, 33, 34, 42 23, 29, 35, 36, 37, 38 31, 33, 36, 38, 41, 42 31, 35, 36, 37, 38 15, 16, 31, 41, 42 . 12, 16, 21,22 11, 12 VI INDEX. Papei^, Common and Silica finish Parallel Motion Pencil, Adjustment of . . *' Metallic and Graphite ^' Oscillation of " Travel of . Piston, Area of . . . Indicator . . 7, 8, 10, 12, 13, 20, 21, 22, 23, 25 '' Pressure on 5, 14, 15, 16, 20, 23, 25-30, 32, 34-38, 41, 42 " Proper fitting of . . . 15, 23, 27, 28, 29, 32, 33 " Speed of Piston-rod, Area of Engine ** Indicator PAGK.-^. 5, 11, 14, 19, 21, 2S . 7, 8, 13 11, 12, 13, 20 . 11, 23 6,29 . 14 21, 40, 41, 42 6, 8, 24, 25, 26, 29, 40, 42 . 21,41 . 10, 11, 12, 13, 22 11, 12 . . .11 16, 41 '* Hollow . '^ Oil Reservoir in Power Consumed by Tenants Horse 39, 40, 43, 44 '' Lost . . 16, 25, 28, 29, 30, 36, 37, 38, 39, 40, 41 '' Nominal, Actual and Effective . 39, 40, 41, 43, 44 of Steam Engine ... 23, 29, 39, 40, 43, 44 " to Drive Machinery 16, 41 " to Overcome Friction of Engine 16, 25, 39, 40, 41, 43, 44 Pressure, Atmospheric . . . . 20, 24, 25, 28, 38 Average .... 15, 23, 32, 34, 35, 37, 40 at Point of Cut-off . . 15, 27, 28, 29, 32, 33, 34 " '' " Release . 15, 25, 29, 34, 40, 42 " ** any Point in Stroke 5, 15, 16, 20, 23, 26-30, 32, 33, 34, 40, 42 Boiler . . . . 15, 21, 27, 30, 31, 42 Counter . Effective . Impelling Initial of Pencil upon Paper Resistinsr . 15, 24, 28, 29, 35, 36, 38 25, 36, 37, 38, 40 . 28, 30, 35, 37 26, 27, 40 . 11, 13, 14, 20 28, 30, 35, 36, 37, 38 INDEX. Vll Pressure, Scales for various . " Springs '' . 6, 7 ** Steam . . 5, 14 ** Terminal . ' ' To Compute Average '^ Vacuum (so-called) Proportional Dividers Reciprocating parts of Engine ** ^* Indicator Richard's Indicator . Scales, Graduated Indicator . Scratches on Indicator Cylinder or Serrated Lines on Diagram Snap-latch .... Springs, Adjusted Drum *^ Graduated Indicator . 6, \ " Other Indicator . Steam Consumed by Engine . Engine, Area of Piston of '* '' Piston-rod of " Computing Power of ^* Condition of . PAGES. 21, 30, 31, 33, 35, 38 10, 12, 14, 21, 22, 29, 35 15, 26, 27, 30, 34-38, 40 15, 25, 29, 34, 40, 42 . 34, 35, 43, 44 14, 16, 21, 31, 37, 38 . 34 . 21 6, 7, 12, 13, 26 7 21, 30, 31, 33, 35, 38 Piston . . .21 . 7, 22, 26, 29 . 19 . 11 12, 14, 21, 22^29, 35 11, 19 15, 16, 31, 41, 42 . 21, 40, 41, 42 . 21, 41 40, 43, 44 . 5, 15, 23 10, Condensing 16, 21, 24, 25, 28, 29, 37, 38, 40 Cylinder 14, 15, 16, 17, 21, 23, 26, 27, 32, 33 Different Diagrams from same 25, 29, 41 Exponent of . 5, 6, 15, 16, 23, 25, 39, 40, 42 Friction of . . .16, 25, 39, 40, 41 Indicator 5, 6 :N'on-condensing . 24, 28, 29, 35, 37, 38 Power of .... 23, 29, 39, 40 Reciprocating Parts of . . . .21 Regularity of Speed of . , , .41 Revolutions of . 20, 21, 24, 29, 41, 42 Speed of Piston of 6, 8, 24, 25, 26, 29, 40, 42 Strokes of " 5, 15, 16, 19, 21, 25, 26, 27, 80, 33, 35, 37, 40, 42 Vlll INDEX. PAGKS. Steam Engine, Style of 21, 25, 35, 36 Steam, Expansion of . . 6, 16, 27, 28, 29, 32, 33, 34 " Gage, Accnracy of .... 17, 25, 30, 31 *^ Line 24, 26, 27, 33, 34, 35, 36 *' Explanation of 27 Lost 15, 27, 28 '' Pressure of . . 5, 14, 15, 26, 27, 30, 34-38, 40 Tenants, Power Consumed by .... 16, 41 Theoretic Curve or Isotliermal Line . 24, 27, 28, 32, 33 " How to Draw . , . . , . 33 Yacuum . . 14, 16, 21, 24, 29, 31, 33, 30, 37, 38, 41, 42 '' Average 16, 37 Perfect 24, 31, 33, 38, 41 '' Gage 21 '' Line 24, 31, 33, 36, 38, 42 '' '' Explanation of 31 " '' Measuring from . 31, 33, 36, 38, 41, 42 Yalves, Condition of . 15, 17, 23, 27, 28, 29, 30, 32, 33 " Exhaust 17, 23, 28, 29, 30 ' Watf s Indicator 6 Wavy Lines 29