Class TJ^Q ^ Book_J±1_ COPYRIGHT DEPOSIT. EK T DESr rl PRKPARbJj THE USE OP STUDENTS IN 'THh MECHANICAL ENGINEERING DEPARTMENT OP THE ASSACHUSETTS jOF TECHNOLOGY IRD P, MILLER 1915 NOTES ON POWER PLANT DESIGN PREPARED FOR THE USE OF STUDENTS IN THE MECHANICAL ENGINEERING DEPARTMENT 2^ OF THE SyK, MASSACHUSETTS INSTITUTE OF TECHNOLOGY EDWARD Fr MILLER 1915 Copyright, 1916 BY EDWARD F. MILLER . H 7 / b U> ',o ■1^ aA420847 FEB 21 1916 INTRODUCTION An attempt has been made to assemble here, in condensed form, data which it is beUeved will be of assistance to one beginning on the laying out of a power plant. j Some of the material has been taken from articles which have appeared either in the Trans- actions of the American Society of Mechanical Engineers or in the engineering periodicals. Abstracts have also been made from Gebhardt's Steam Power Plant Engineering, from Koester's Steam Electric Power Plants, from Peabody and Miller's Steam Boilers, from Illustrations of Steam Engines, Steam Turbines, etc., from trade catalogues and from publications gotten out by manufacturers of the different pieces of apparatus which enter into the equipment of a power plant. E. F. M. TABLE OF CONTENTS Distribution of Heat 5, 6 Boilers 7-15 Methods of supporting; dimensions of; flues for; using fuel oil; stack for boilers using fuel oil. Economizers 16-23 Calculation of size of; tables of dimensions of. Mechanical Stokers 24-25 Chimneys, Flues and Draught 26-29 Feed Pumps — Venturi Meter 29-33 Engines 34-49 Steam Consumption of; calculation of power of; cylinder efficiency of steam engines and steam turbines; Rankine efficiency and cylinder efficiency; calculation of bleeder type of engine or turbine; bleeding steam; comparison of engines and turbines and water rate of small tur- bines; general dimensions of and floor space required by engines. Condensers and Accessories 50-68 Surface; jet; air pumps; dry air pumps; circulating pumps; exhaust relief valves. Flow of Steam in Pipes '. 69-71 Feed Water Heaters 72-75 Cooling Towers 76-80 Calculation of; power required by fan; extra work put on circulating pump. Spray Nozzles . 80-81 Centrifugal Pumps 82-90 Characteristics of; friction of water in pipes. Coal Handling and Coal Bunkers 91-106 Pivoted bucket conveyors; belt conveyors, scraper conveyor; power required; crushers; parabolic bins. Foundations, Concrete Floors, Walls 106-125 Costs . 126-139 Cost of various items entering into power house construction and into equipment of power house; cost of operation and distribution of operating costs; failure to make guarantees as to performance as affecting cost. Piping and Pipe Fittings 140-156 Dimensions of fittings; list price and discounts; cast iron pipe for water work. Pipe Covering 157-159 Cost of; insulating value of different thickness of; covering for flues and for boiler drums. Specifications 160-178 Surface condenser; hot well pump; dry vacuum pump; low pressure turbine; direct acting boiler feed pump; automatic pump and receiver; horizontal cross compound non-condensing Cor- liss engine; steam driven centrifugal pumping unit; motor driven centrifugal pumping unit. Cuts of Stations 179-185 DISTRIBUTION OF HEAT It is generally known that but a small proportion of the heat of the coal burned in a power plant goes into power. In cases where there is a large demand for steam for heating during eight months of the year the exhaust steam from the engines or turbines used for power or lights may be saved by utilizing this steam in the heating system. Under such conditions the cost of power for the period of heating is low and during this period the economy of the engine is of little moment provided there is never a surplus of exhaust steam. During the remaining four months when no heat is required, the economy of the engine is of importance. Under all conditions the efficiency of the boiler affects the cost of operation. The distribution of heat throughout a plant may be illustrated by the two cases worked out below. Case I Engine uses 30 lbs. steam, 100 lbs. gage per Brake Horse Power per hour; exhausting out- board. Feed water enters boiler at 70°. No heater installed. Per Cent hij Weight B. T. U. Engine 30 (1187-38) 100 34,470 Feed Pump .6 (1187 -38) 2 689 Drips, radiation .45 (1187 -38) 1.5 517 35,676 One horse power hour corresponds to 2,545 2 545 The thermal efficiency of the engine end = -^-x-^^r^ = .0713 35,676 The boiler supplying steam we will assume to use a coal of 14,600 B.T.U. to the lb. and that the Per Cent Per Cent of heat of coal utilized by boiler is ■......, 68 Per Cent lost by radiation, loss of coal through grate, etc. is 10 Per Cent of heat of coal carried off by flue gas is 22 100 14,600 X.68 = 9,928 B. T. U. Coal per Brake Horse Power Hour = -^ ' = 3.594 lbs. The overall efficiency of the plant is .0713 x.68 = .0485 ^^^^^^^^g 3.594 x\t 600 =-Q^^^ 3.594 X 14,600 = 52,470 B. T. U. per I. H. P. hour. which may be found by dividing „ ^^. ' , , -^^ = .0485 3.594 X 14,600 NOTES ON POWER PLANT DESIGN Case IT Modern Turbine or Engine Plant using Superheated Steam at high pressure with 28" vacuum in condenser. Economizer, Primary and Secondary heaters installed. Coal 14,600 B. T. U. per lb. Combined Boiler and Economizer Efficiency = 76 per cent. Boiler pressure 184 lbs. absolute, superheat 52° F. Back pressure 1 lb. absolute. Feed water enters primary heater at 65°; leaves at 88°; enters secondary at 88°; leaves at 150°; enters economizer at 150°; leaves at 300°. Engine or turbine requires 12.1 lbs. per I. H. P. hr. or 12.1 ^.93 = 13 lbs. per brake horse power hour. Per ( Engineor turbine 13 (1228.6 -118) Feed Pump Circulating Pump for Condenser Wet Pump . Dry Vacuum Pump Drips, radiation, etc. 5 hy Weight B. T. U. 100 14,438 1.5 216 3.0 432 1.5 216 1.5 216 1.5 216 15,734 2,545 15,734 = .1617 the engine efficiency assuming feed pump part of engine room outfit. .1617 X.76 = overall efficiency = .1229 The auxiliaries use 9% of engine steam, or .09 xl3 = 1.17 lbs. hr. per engine horse power. There is consequently 13 +1.17 = 14.17 lbs. passing through primary and secondary heater and through economizer per 13 lbs. supplied to engine. (88 - 65) 14.17 = 326 B. T. U. recovered in Primary heater. (150 - 88) 14.17 = 878 B. T. U. recovered in Secondary heater. The total coal per engine horse power output hr. is 15,734 = 1.418 lbs. 524-70 B.T.U. from Coal -^ 14,600 X.76 1.418 X 14,600 = 20,702 B. T. U. supplied by coal per engine H. P. output. 20,702 X.1229 = 2,545 B. T. U. put into work or one horse power hour. Had the primary and secondary heaters not been supplied there would have been required 326 -1-878 additional coal by an amount equal to .. . r.r.r, ^^ = -109 lbs. making the coal consumption per engine H. P. hr. = 1.528 lbs. The results of these two calculations have been plotted in Fig. 1, the area of the small square in each case repre- senting the heat units to be supplied for one horse power hour output. The full lines represent Case I and the dotted lines Case II. The heat exhausted outboard per horse power hour is for Case 1 35,676-2,545 = 33,131 B. T. U. The heat exhausted to the condenser in Case II is 14,438 - 1,545 - 326 = 11,567 B. T. U. The 2,545 being the amount put into work and the 326 that transferred to the feed water in the primary heater. Many plants like that cited in Case I with constantly growing demands for power, have overloaded engines, and boilers which cannot be run at increased pressures. Often times if condensing water be available a low pres- sure turbine may be installed and the exhaust of the engine at from 1 to 5 lbs. gage pressure passed through the 3S676 to Engine and Aux. -^ 347 7 O to Engine -^ Z070Z B.TM. -from Coal^ 15734- to Engine and Aux. \ ~U'4S3~r^lEng//7e'-^~>\'^* 254-5 NOTES ON POWER PLANT DESIGN 7 turbine and additional power amounting to from 50 to 80 per cent of the engine power obtained from the exhaust steam. In general an engine designed to run non-condensing is not made sufficiently strong and the bearing surfaces are not large enough to stand the extra load brought to the parts when the engine is run condensing. BOILERS With few exceptions every large power plant where the units are steam driven, is equipped with some form of water tube boiler. This type is selected (1) because large powers can be obtained from single units, (2) because of the saving in floor space over that of any other type suitable for large power houses and (3) because high steam pressures in large units can be carried without any appreciable thickening of the metal through which the heat of the fire is transmitted. A plant which is to be kept in continuous operation should have a sufficient number of units so that with one laid off for repairs the other units are able to carry the entire load. Hand fired boilers working with natural draft can be run 33 per cent above their rating, with- out difficulty, provided the draft at the smoke outlet at normal rating is at least .5" of water. Stoker fired boilers working either with forced draft, induced draft or with both forced and induced draft may be run at times of peak load at 300 per cent of their rating. In recent years the boilers in nearly all of the power stations have been planned to develop from 150 to 200 per cent of their rating during ordinary running, and even higher than the figures given in times of emergency. But little loss in thermal efficiency, results from forcing a boiler to 150 per cent of its rating. When boilers are supplied with attached superheaters it is not advisable to have any possibility of a large amount of saturated steam being drawn from the drums of the boiler as such a proce- dure would result in the burning out of the superheater. Boilers rated 400 to 600 H. P. cost per H. P., erected on foundations provided by the purchaser, from $16.50 to $17.50; with attached superheater, the price increases from $1.00 to $1.50 per H. P. If the demand on a boiler plant amounted to 3600 H. P. and 2000 H. P. were installed, the boilers running 180 per cent of their rating, the reduction in first cost would amount to ($16.50 + $1.50) xl600 = $28,800. Taking interest, taxes, insurance, repairs and depreciation as 13 per cent, the saving on overhead charge would amount to .13 x 28,800 = $3,744. Any slight loss in economy due to forcing the boilers would be more than offset by the reduced overhead on the building due to the smaller boiler room required. Water tube boilers are given a nominal rating on a basis of 10 sq. ft. of heating surface per boiler horse power. Tables giving some general dimensions of the Stirling, Heine and Babcock and Wilcox boilers follow. These may be useful in getting general overall dimensions, weights, etc. It is evident that any of these boilers may be modified within certain limits. As an illustration suppose it is found advisable to put in a B. & W. boiler 27 sections wide, 14 tubes high, tubes 18 ft. long. What would be the increase in width and in height over a boiler 21 wide and 9 high. The width increases approximately 7" per section and the height approximately 6" per tube, making the width and height of the boiler 19' - 6" and 18' — 3" respectively. With 4" tubes the heating surface added per tube is 18' x4 X 3.1416 ^___ .^ r^ = 18.85 sq. ft. The 30 tubes add 566 sq. ft. or 57 H. P., making the rating 57 + 396 = 453 H. P. It must be remembered that adding heating surface does not necessarily increase the power of a boiler ; the grate surface must be increased in the proper proportion at the same time. Roughly a sq. ft. of grate is to be added for two 18 ft. tubes. 8 NOTES ON POWER PLANT DESIGN HEINE WATER TUBE BOILER This boiler requires a space at the back as it is cleaned from the ends. Any number of boilers of this type can be set side by side. The space in front of the boiler should be sufficient to allow of the renewal of a tube. The length of setting from fire front to rear of brickwork is always 1 foot 4 inches longer than the length of the tubes, for instance, the setting of a 90 horse-power boiler is 17 feet 4 inches long and a 101 horse-power boiler is 19 feet 4 inches long. The shell with manhead extends about 15 inches beyond rear of setting, so that if possible a 4-foot space should be allowed behind the setting for access to same. In special cases the manhole is placed in the front head, or an opening may be made in the building wall opposite manhole, in which case 2 feet behind setting will be sufficient. The width of setting may be determined by adding the thickness of brick walls to the width of furnace. Thus, three 101 horse-power boilers in a battery, with 19 inches side and 28 inches divi- sion walls, will be 19^' + 53" + 28" + 53" + 28" -f- 53" -t- 19" = 21' 1". Existing walls may be utilized where space is limited, and the outside walls here reduced to a furnace lining 9 or 10 inches thick. The grate-surface given for bituminous coal is such that the rating may be easily developed with a J/^-inch draught at the smoke outlet. The grate area given for anthracite pea coal is that necessary in order to develop the rating of the boiler with i'2-inch draught at the smoke outlet. For convenience of handling it is advisable to limit the grate length for anthracite coal to 7 feet 6 inches. Where this does not give area enough for the desired maximum capacity it is necessary to increase the draught. Standard grate lengths are 6 feet 6 inches, 7 feet and 7 feet 6 inches. Safety-valves are provided as required to meet local inspection laws. NOTES ON POWER PLANT DESIGN Heine Water-Tube Boilers Tubes 31/2" Shells Steam Outlet Square Feet Diameter Horse- Height of Diam. power Heating surface Height of Flange Above Center Line Above Floor Feed-pipe No. Length No. Diam Length Diam. Floor Level Level Speoia 1 1 Ins. Ft. Ins. Ins. Ft. Ins. Ft. Ins. Ins. 90 903 53 16 for 36 19 41/2 4 11 71/2 9 91/2 IV2 101 1010 53 18 all 36 21 41/2 4 11 71/2 9 91/2 IV2 113 1130 68 16 Horse 36 19 41/2 4 12 21/2 10 41/2 11/2 126 1263 68 18 Power 36 21 41/2 4 12 21/2 10 41/2 11/2 127 1273 77 16 36 19 41/2 5 12 21/2 10 41/2 lly^ 143 1424 77 - 18 36 21 41/2 5 12 21/2 10 41/2 11/2 153 1533 94 16 36 19 4 1/2 5 12 91/2 10 11 1/2 11/2 171 1714 94 18 36 21 41/2 5 12 91/2 10 111/2 11/2 142 1420 86 16 42 19 6V2 5 12 8 1/2 10 10 11/2 158 1588 86 18 42 21 61/2 5 12 8 1/2 10 10 11/2 170 1708 105 16 42 19 6V2 5 13 31/2 11 5 11/2 191 1911 105 18 42 21 61/2 5 13 31/2 11 5 11/2 156 1564 95 16 42 19 6 1/2 5 12 8 1/2 10 10 11/2 175 1749 95 18 42 21 61/2 5 12 8 1/2 10 10 IV2 188 1883 116 16 42 19 6 1/2 5 13 31/2 11 5 11/2 210 2106 116 18 42 21 6 1/2 5 13 31/2 11 5 11/2 171 1716 104 16 48 19 91/4 6 13 21/2 11 91/2 2 192 1920 104 18 48 21 91/4 6 13 21/2 11 91/2 2 206 2061 127 16 48 19 91/4 6 14 21/2 12 71/2 2 230 2306 127 18 ' 48 21 91/4 6 14 21/2 12 71/2 2 224 2244 138 16 - 48 19 91/4 6 14 21/2 12 71/2 2 250 2508 138 18 48 21 91/4 6 14 21/2 12 71/2 2 262 2621 163 16 48 19 91/4 6 14 91/2 13 21/2 2 293 2931 163 18 48 21 91/4 6 14 91/2 13 21/2 2 241 2417 149 16 48 19 91/4 6 14 6 12 10 2 270 2702 149 18 48 21 91/4 6 14 6 12 10 2 282 2826 176 16 48 19 91/4 6 15 1 13 5 2 316 3160 176 18 48 21 91/4 6 15 1 13 5 2 258 2586 160 16 48 19 91/2 8 14 6 1/2 12 101/2 2 289 2892 160 18 48 21 91/2 8 14 6 1/2 12 10 1/2 2 302 3024 189 16 48 19 91/2 8 15 11/2 13 51/2 2 338 3383 189 18 48 21 91/2 8 15 11/2 13 51/2 2 Grates Space Occu pied Standard Setting Special Settng Low CeiUngs Blow off- Bituminous Anthracite Height Height Height Height Cocks, Coal Pea Coal over over over over IV2" Furnace Safety- Breeching Shell Breeching Diam. Width Length Area Length Area Valve at Front No. Ft. Ins. Ft. Ins. Sq. Ft. Ft. Ins. Sq. Ft. Ft. Ins. Ft. Ins. Ft. Ins. Ft. Ins. 2 4 5 4 6 20.3 4 71/2 20.4 13 41/2 12 8 10 10 11 2 2 4 5 5 22.5 5 21/2 23.0 2 4 5 5 22 . 5 5 10 25.7 13 11 1/2 13 4 11 5 11 11 2 4 5 5 6 24.7 6 51/2 28.6 2 5 5 25.4 5 9 28.8 13 111/2 13 4 11 5 11 11 2 5 5 6 27.9 6 6 32.5 2 5 6 30.4 6 11 34.7 14 6V2 13 11 12 12 7 2 5 6 6 32.9 7 9 38.8 2 5 7 5 28.4 5 9 32.2 14 71/2 13 9 11 101/2 12 6 2 5 7 5 6 31.2 6 5 35.9 2 5 7 6 34.0 6 11 38.6 15 21/2 14 4 12 51/2 13 2 2 5 7 6 6 36.8 7 9 43.4 2 6 2 5 31.4 5 9 35.4 14 71/2 13 9 11 101/2 12 7 2 6 2 5 6 34.4 6 6 39.9 2 6 2 6 37.5 6 11 42.7 15 21/2 14 4 12 51/2 13 2 2 6 2 6 6 40.6 7 9 47.7 2 6 9 5 34.3 5 9 38.8 15 3 14 7 12 11 13 9 2 6 9 5 6 37.7 6 6 43.6 2 6 9 6 41.1 6 11 46.8 16 3'/2 15 3 13 9 14 11 2 6 9 6 6 44 . 5 7 9 52.2 2 7 4 5 44 . 6 6 11 50.9 16 31/2 15 3 13 9 15 2 7 4 5 6 48.4 7 9 56.8 2 7 4 6 6 48.4 8 1 59.5 16 101/2 15 10 14 4 15 7 2 7 4 6 52.0 3 7 11 6 6 48 . 2 6 11 54.7 17 41/2 15 10 14 15 6 3 7 11 6 52 . 2 7 9 61.3 3 7 11 6 6 52.2 8 1 64.0 17 IIV2 16 6 14 7 16 2 3 7 11 7 56.1 3 8 6 6 6 51.7 6 11 58.6 17 5 15 10 14 01/2 15 6 3 8 6 6 56. 0' 7 9 65.6 3 8 6 6 6 56.0 8 1 68.6 18 16 6 14 71/2 16 2 3 8 6 7 60.2 10 NOTES ON POWER PLANT DESIGN Heine Water-Tube Boilers Tubes Steam Outlet 31/2" Shells Heiu-ht nt Square Diameter Height of Center Line Horse - Feet. Heating Flange Above P Floor ibove Floor Level surface No. Length No. Diam. Length Diam. Level Special Ins. Ft. Ins. Ins. Ft. Ins. Ft. Ins. Double- 280 2808 171 16 2 36 19 41/2 8 14 1 11 11 1/2 shell 314 3140 171 18 for 36 21 41/2 for 14 1 11 111/2 boilera 328 3280 202 16 all 36 19 41/2 all 14 8 12 6 1/2 367 3669 202 18 horse- 36 21 41/2 horse- 14 8 12 6 1/2 297 2978 182 16 powers 36 19 41/2 powers 14 \ 11 ni/2 333 3330 182 18 36 21 41/2 14 1 11 111/2 348 3479 215 16 36 19 41/2 14 8 12 6 1/2 389 3892 215 18 36 21 41/2 14 8 12 6I/2 254 2546 154 16 36 ■ 19 41/2 12 101/2 10 101/2 285 2848 154 18 36 21 41/2 12 101/2 10 lOi/a Two 284 2840 172 16 42 19 6 1/2 13 41/2 11 4 sections 317 3176 172 18 42 21 6 1/2 13 41/2 11 4 over 341 3416 210 16 42 19 6 1/2 13 111/2 11 11 one 382 3822 210 18 42 21 6 1/2 13 111/2 11 11 furnace. 312 3128 190 16 42 19 6 1/2 13 41/2 11 4 350 3498 190 18 42 21 6 1/2 13 41/2 11 4 576 3766 232 16 42 19 6 1/2 13 111/2 11 11 421 4212 232 18 42 21 6 1/2 13 111/2 11 11 440 4400 274 16 42 19 6 1/2 14 6 1/2 12 6 492 4924 274 18 42 21 6 1/2 14 6 1/2 12 6 343 3432 208 16 48 19 91/4 13 101/2 11 9.V2 384 3840 208 18 • 48 21 91/4 13 101/2 11 91/2 412 4122 254 16 48 19 91/4 14 101/2 12 71/2 461 4612 254 18 48 21 91/4 14 101/2 12 71/2 482 4822 300 16 48 19 91/4 15 51/2 13 21/2 539 5396 300 18 48 21 91/4 15 51/2 13 21/2 448 4488 276 16 48 19 91/4* 14 101/2 12 71/2 501 5016 276 18 48 21 91/4 14 101/2 12 71/2 524 5242 326 16 48 19 91/4 . 15 51/2 13 21/2 586 5862 326 18 48 21 91/4 15 51/2 13 21/2 Blowoff Grates Space Occupied Diam. Standard Setting Special Setting, Low Ceilings Feed- Cocks, F urnace Bituminous Anthracite Height Hei ght Height Height pipe 1 \L" Width Coal Pea Coal over over over over ] Diam. L sngth Area Length Area Safety-Valve Breeching Shell at Front Breeching Ins. Nn Ft. Ins. F t. Ins. Sq. Ft. Ft. Ins. Sq. Ft. Ft. Ins. Ft. Ins. Ft. Ins. Ft. Ins. 2 1/2 "4" c 1 « 55.2 7 63.6 15 41/2 15 6 13 1 . 14 5 21/2 2y2 for c 1 6 6 59.8 7 10 71.3 all £ 1 e 59.8 8 3 74.5 15 111/2 16 1 13 8 15 2V2 2V2 2 1/2 horse- powers 1 8 8 7 e c 6 64.4 58.8 6 63 . 6 7 7 10 67.5 75.6 15 41/2 15 6 13 1 14 6 8 e 63.6 8 2 79.0 15- 111/2 16 1 13 8 15 1 21/2 ) 8 ' 6 68.5 2-11/2 2-1 1'i 1( ) 7 r ) 53 . 7 5 6 57.7 13 111/2 13 10 11 11 12 11 ) 7 ) 6 59.0 6 2 64.8 2-1 1/2 2-11/2 2-11/2 L 9 ) 59 . 7 5 6 64.5 14 71/2 14 3 12 41/2 13 3 I 9 L 9 c ) 6 65 . 6 ) 71.5- 6 6 2 7 72.0 77.3 15 21/2 14 10 12 111/2 13 10 2-1 1/2 2-11/2 2-11/2 2-11/2 2-11/2 2-1 1/2 9 e ) 6 77.3 7 5 86.7 > 65.7 5 6 70.8 14 71/2 14 3 12 41/2 13 9 \ ) 6 72 . 1 ) 78 . 6 6 6 2 7 79.5 85.4 15 21/2 14 10 12 111/2 14 6 i ) 6 85 . ) 85 . 7 7 5 9 95.7 100.0 15 91/2 15 5 13 6 1/2 15 1 2-2 r 9 91.5 5 71.5 5 7 78.0 15 3 14 7 12 11 13 9 2-2 > 6 78.5 6 2 87.2 2-2 \ 3 85 . 3 6 8 93.6 16 31/2 15 9 13 9 14 11 2-2 ( 3 6 92.8 7 5 104.8 2-2 3 92.3 7 9 109.5 16 101/2 16 4 14 4 15 6 2-2 2-2 5 3 ( f 6 99 . 7 5 92.7 6 8 101.8 16 31/2 15 9 13 9 15 2-2 2-2 5 3 5 3 ( f 3 6 100.3 3 100 . 3 7 7 6 10 114.0 119.1 16 101/2 16 4 14 4 15 7 2-2 5 3 1 6 108.0 NOTES ON POWER PLANT DESIGN 11 STIRLING BOILERS These boilers clean from the side, and only two can be set together without a space between. If necessary the boiler may be set without a space at the back, but it is advisable to have at least 3 feet back of the rear wall. These boilers are also built with attached superheaters. The superheater is placed at differ- ent parts of the setting, according to the number of degrees of superheating desired. The following table gives dimensions of this boiler for different boiler horse-powers. If the boiler is equipped with a superheater, deduct 10 per cent from the rated horse-power. If, however, the superheater is flooded the capacity of the boiler is increased approximately 7 per cent above the ratings given. Horse-Power of Stirling Boilers CLASS B-low P E B A Q F R K L N Width of Height Setting 11' 11" 15' 41/2" 15' 3" 15' 8" 18' 9" 18' 10" 20' 7" 20' 8" 214.10" 22' 4" 24' 6" Single Battery* Depth ft. in. feet 14' 0" 18' 7" 16' 3" - 14' 0" 16' 0" 18' 9" 16' 9" 18' 2" 17' 7" 18' 3" 18' 10" 5 6 10 50 50 6 11 55 '75 60 6 6 12 65 90 70 7 13 75 iis 100 80 iis i45 lib i45 i.56 165 i75 7 6 14 85 130 115 90 130 165 155 160 170 185 195 8 15 95 145 125 100 145 180 175 180 185 205 220 8 6 16 105 160 140 110 160 200 190 200 205 230 240 9 17 115 175 150 120 175 215 205 215 225 250 260 9 6 18 125 190 165 130 190 235 225 235 245 270 285 10 19 135 205 175 140 205 255 240 250 260 290 305 10 6 20 140 220 190 150 215 270 260 270 280 310 330 11 21 150 230 200 160 230 290 275 285 300 330 350 11 6 22 160 245 215 170 245 310 295 305 315 350 370 12 -0 23 170 260 225 180 260 325 310 325 335 370 395 12 6 24 180 275 240 190 275 345 330 340 355 395 415 13 25 190 290 250 200 290 360 345 360 375 415 435 13 6 26 200 305 265 210 305 380 360 375 390 435 460 14 27 210 320 275 220 320 400 380 395 410 455 480 14 6 28 220 335 290 230 335 415 395 410 430 475 505 15 29 230 350 300 240 350 435 415 430 450 495 525 15 6 30 240 365 315 250 360 450 430 450 465 515 545 16 31 250 375 330 260 375 470 450 465 485 540 570 16 6 32 260 390 340 270 390 490 465 485 505 560 590 17 33 265 405 355 280 405 505 485 505 520 580 610 17 6 34 275 420 365 290 420 525 500 520 540 600 635 18 35 285 435 380 300 435 545 515 540 560 620 655 sides. * The horse-power is double for battery width shown. Single boilers require an alley on one side; battery boilers require an alley on both 12 NOTES ON POWER PLANT DESIGN least 5 feet between each BABCOCK AND WILCOX BOILERS These boilers clean from the side. ,There must be a space of at set of two. The tables give space taken up by boilers with vertical headers. For inclined headers, any number of tubes high, add 3 feet 8 inches to the length given. A double-deck boiler is 10 inches higher than a single-deck boiler of same number of tubes high. Space must be left in front of the boiler to enable the lowest tube to be replaced. Babcock AND "Wilcox Veetical Header Boilers.— -s mg le Deck Hor.se- power Heating Sections Drums at 10 surface, Steam Square Square Nozzle Opening Feet Feet Wide High Long N 0. Dia. Length Dia. Flange Dia. Flange Ft. Ins. Ft. Ins. Ins. Ins Ins. Ins. One 101.8 1018 6 9 16 36 18 7Vd 5 11 5 11 Boiler 114.3 L143 6 9 IS 36 20 2 5 11 5 11 in 117.5 1175 7 9 16 36 18 7Vi 5 11 5 11 One 132.0 L320 7 9 18 36 20 2 5 11 5 11 Battery. 134.5 1345 8 9 16 42 18 71/4 5 11 5 11 151.0 1510 8 9 18 42 20 2 5 11 5 11 150.2 L502 9 9 16 42 18 71/4 5 11 5 11 168.7 1687 9 9 18 42 20 2 6 121/2 6 121/2 203 . 6 2036 12 9 16 < 36 18 7V4 8 15 8 15 228.7 2287 12 9 18 2 36 20 2 5 11 8 15 235 . 1 2351 14 9 16 36 18 7V4 5 11 8 15 264.0 2640 14 9 18 2 36 20 2 5 11 8 15 269.0 2690 16 9 16 2 42 18 7V4 5 11 8 15 302.1 3021 16 9 18 2 42 20 2 5 11 8 15 300.5 3005 18 9 16 2 42 18 71/4 5 11 8 15 337 . 5 3375 18 9 18 2 42 20 2 5 11 8 15 352 . 7 3527 21 9 16 c 36 18 71/4 5 11 10 171/2 396.0 3960 21 9 18 3 36 20 2 5 11 10 171/2 1 \Iud-drums Height from Front f 3 rates Safety Valve Floor to top of Boiler to Center of Hand Blow-off Steam Steam No DlQ I >ed Hole No. Dia. Outlet Outlet Length Width Area Ins I QS. No. Ft. Ins. Ft. Ins. Ft. Ins. Ft. Ins. 3V '2 11/2 1 2 14 8 3 2 6 3 10 23.00 3V '2 11/2 1 2 14 8 ar 7 3 10 26.81 31/ '2 IV2 1 2V2 14 8 8 2 6 4 5 26.50 4 11/2 1 21/2 14 8 7 4 5 30.94 4 IV2 2 2 '72 15 2 6 5 30.00 4 iy2 2 21/2 15 2 7 5 35.00 4 iy2 2 IV2 15 2 6 5 7 33.50 4V 'j 11/2 2 2V2 15 2 7 5 7 39.06 2 3V 2 3 2 2V2 15 8 6 7 4 44.00 2 3V 2 2 3 2 2'/2 15 8 7 7 4 51.31 2 4 2 4 2 2V2 15 8 6 8 6 51.00 2 4 2 4 2 2V2 hi 8 7 8 6 59.50 2 4 2 4 2 21/2 2 6 9 8 58.00 2 4 2 4 2 2V2 16 2 7 • 9 8 67.66 2 4 2 4 2 21/2 16 2 6 10 10 65.00 2 4V '2 2 4 2 2V2 16 41/2 7 10 10 75.81 3 4 21/2 4 3 21/2 15 9 6 12 7 75.50 3 4 2V,. 4 3 2V2 15 9 7 12 7 88.06 Spac e Occupiec 1 Ai 5prox. eight Su 1 Lpprox. spended A' eight Approx. Total Weight Approx. of Ir icluding of Shipping Length Widi .h Vi Taier \ Vater Setting Weight R ed Brick Fire-brick Ft. Ins. Ft. ins. No. No. 17 91/2 6 8 < ),200 29 ,300 120 ,000 26 ,000 14 ,200 3250 19 9 6 8 1 3,170 31 ,300 130 ,600 27„500 15,600 3550 17 OVi 7 3 1 D,020 32 ,100 126 ,000 28 ,600 14 ,500 3450 19 9 7 3 1,080 34 ,300 137 ,800 30 ,300 16 ,000 3700 17 91/2 7 10 2 ,330 38 ,600 135 ,300 32,700 15,100 3700 19 9 7 10 i,720 41 ,300 147 ,000 34 ,800 16 ,600 3950 17 91/2 8 5 5,220 41 ,300 142 ,800 36 ,400 15 ,300 3950 19 9 8 5 1,670 44 200 155 100 38 ,300 16,700 4100 17 91/2 10 2 1! 5,400 59 200 151 ,500 47 ,400 15 ,800 4000 19 9 10 2 2( ) ,.340 63 ,200 163 ,600 50 ,300 17 ,400 4550 17 91/2 11 4 2( ),040 64 ,900 162 ,500 53 ,600 16 ,400 4400 19 9 11 4 2. 2,160 69 ,300 175 ,100 56 ,000 17 ,900 4700 17 91/2 12 6 2- 1,600 78 ,000 178 ,900 62 ,200 17,200 4700 19 9 12 6 2" 7,440 83 ,400 191 ,900 65 ,900 18,900 5200 17 91/2 13 8 2( 5,440 83 ,600 190 ,700 68 ,400 17 ,800 4950 19 9 13 8 2' ) ,340 89 ,300 204 ,900 72 ,500 19 ,.500 5300 17 9V2 15 5 3( 3,000 1 08 ,700 209 ,800 79,100 18,100 5200 19 9 15 5 3. 5,240 1 16 ,200 224 ,100 83 ,900 20 ,000 5400 NOTES ON POWER PLANT DESIGN 13 Babcock and Wilcox Vertical Header Boilers, — Single Deck Horse-power at 10 Sq. Feet Heating- surface Sq. Ft. Width of Settings Ft. Ins. Shipping Weight Red Brick Number Fire Brick Number Two Boilers in One 203.6 228.6 235.0 264.0 2036 2286 2350 2640 11 11 11 11 13 1 13 1 52 ,000 55 ,000 57 ,200 60 ,600 20 ,300 22 ,000 20 ,900 23,000 6,500 7,100 6,900 7,400 Battery. 269.0 302.0 2690 3020 14 3 14 3 65 ,400 69 ,600 21 ,900 24 ,000 7,400 7,900 300.4 337.4 3004 3374 15 5 15 5 72 ,800 76 ,600 22,200 ■ 24 ,300 7,700 8,200 407.2 457.4 4072 4574 19 6 19 6 94 ,800 100 ,600 26 ,800 29 ,400 8,000 9,100 470.2 528.0 4702 5280 21 10 21 10 107 ,200 112 ,000 27 ,900 30 ,500 8,800 9,400 538.0 604.2 5380 6042 24 2 24 2 124 ,400 131 ,800 30 ,200 32 ,400 9,400 10,400 601.0 675.0 6010 6750 26 6 26 6 136 ,800 145 ,000 . 31,600 33 ,600 9,900 10 ,600 705.4 792.0 7054 7920 30 30 158 ,200 ■ 167 ,800 31 ,650 34 ,750 10 ,400 10 ,800 Both the B. & W. and the Stirhng have cleaning doors for blowing soot from the tubes on the side, consequently only two boilers can be placed side by side without an aisle. The height of the tubes above the grate can be made to suit the requirements of the engineer ; a much greater height is used now than was the custom a few years ago. In many boiler houses the boilers are located on the first floor above the basement which may be at ground level or below ground level. The space below the boiler is used for collecting the ash, for the main steam line and feed pump lines, for conveying machinery, etc. The boilers are supported, in such cases, by steel beams running between the columns which must be spaced to suit the width of the boilers used. The column spacing is often made unequal to allow for a 5 or 6 ft. aisle between batteries. In some cases where small units are installed, the two boilers in any one battery are carried at the front end by steel beams, running from the face of a column at one side of the battery to a similar column at the other side. This method of supporting requires a rather heavy beam. More often there is a column in the center of the battery. In every case the columns must be protected by a sleeve so that should the brickwork of the boiler become burned through, there would be no possibihty of the heat of the fire softening the column. This sleeve is frequently made of thin iron encircling the column to a height of three cr four feet above the tubes, the sleeve being open at the bottom and at the top to allow of a circulation of air between the sleeve and the column. When boilers are carried by beams attached to the side of the columns there is an eccentric load brought to the end columns. These columns adjacent to the aisles between batteries must be diagonally braced above the boilers on account of this eccentric loading. The back ends of the boilers may be supported in the same way as the front ends or I beam uprights resting on steel floor beams, may ssrve to carry the cross beams from which the drums of the boiler are suspended. When a boiler house is arranged with a double row of boilers, having a firing aisle in the centre the coal pocket is often suspended from the columns so as to utilize the space over the firing aisle. Economizers if used, would then be located over the boilers at the back end; this plan utilizes space otherwise wasted but makes a boiler room which is dark. An arrangement found in some of the large plants in Chicago secures both a well lighted and a well ventilated boiler room. 14 NOTES ON POWER PLANT DESIGN The boilers at both front and back are supported by columns which are carried up to the roof. A coai pocket is hung between these columns over each row of boilers and the middle bay, which is the firing aisle, is open to the roof, which in this bay is of the monitor type. FLUES FOR BOILERS The area of the flue leading from a row of boilers to the stack should be as great as the area of the stack designed to carry the row. It is evident that a greater draft obtained from a high stack would diminish the cross sectional area required by a shorter stack giving less draft. The old rule which applied to hand fired boilers by which the flue area was made from 1/8 to 1/10 the grate area does not hold with stoker fired boilers under which coal is burned at three times the rate found common with hand fired boilers. To illustrate the method of determining the size of the flue for a row of boilers let us assume that 5000 lbs. of coal are burned per hour under a battery of boilers. Chimney 150 feet high. Referring to the chart of chimney capacity in the section treating of chimneys, it is seen that a chimney 150 feet tall will take care of 176 lbs. of coal per hour per sq. ft. of chimney area accord- ing to Kent's values and 157 lbs. according to Christie's values. It appears from these figures that a flue of from 28 to 32 sq. ft. area is required. BOILERS USING FUEL OIL In the middle western states and in the southwestern part of the country oil is in general use for steam generation. On account of the sudden fluctuations in the price of oil here in the east very few concerns in this part of the country have used oil. Contracts are now being made, however, for delivery of oil at a fixed price through a long period of years and there is every reason to believe that the use of oil in this part of the country will increase. Texas oil has a heating value of approximately 18,500 B. T. U. per pound. It contains gen- erally about 2 per cent of moisture although in some cases as much as 25 per cent has been found. The gross efficiency of an oil fired boiler plant is with good management about 82 per cent; as 2 per cent of the steam made is used in heating the oil and in spraying it, a net efficiency of 80 per cent may be expected. An efficiency of 75 per cent would be consid6red very good for a coal fired boiler, 70 being nearer that obtained in every day running in the best plants. The price of oil varies either side of $1.00 per barrel of 42 gallons, 8 lbs. to the gallon. A table giving the number of barrels of oil equivalent to a ton of coal burned with boiler effi- ciencies varying from 65 to 75 per cent will enable one to make a comparison of the cost of evapora- tion, using oil at so much a barrel as against coal of a certain price per ton. Heat Value of Coal 14,600 per lb. Equivalent Evaportation per lb. coal from and at 212° F. in lbs Barrels of oil 336 lbs. to barrel 18,500 B. T. U. per lb. burned with 80 per cent net efficiency equiv- alent to one ton of coal of 14,600 B. T. U. to lb. Oil weighs 8 lbs. per gallon. 42 gallons per barrel. The crude oil has to be stored in steel tanks, generally placed underground outside of the building. The oil in the tank must be heated by a steam coil in order to keep it sufficiently fluid Boiler Efficiency .750 .725 .70 .675 .650 11.284 5.543 10.908 4.257 10.532 4.110 10.392 3.964 9.779 3.817 NOTES ON POWER PLANT DESIGN 15 to flow through the suction pipe of the oil pump supplying the burners with oil under 30 to 50 lbs. pressure. The exhaust of the oil pump is frequently used to still further heat the oil before it enters the burner. The temperature of the oil should not be high enough to cause the gas to volatilize as this would cause the flame at the burner to be extinguished and might result in a flooding of the furnace and an explosion. The advantages and the disadvantages of petroleum as a fuel compared with coal are given in "Steam" thirty-fifth edition, Babcock and Wilcox Co.'s catalogue, page 214, as follows: The advantages of the use of oil fuel over coal may be summarized as follows: 1st. The cost of handling is much lower, the oil being fed by simple mechanical means, result- ing in: 2nd. A general labor saving throughout the plant in the elimination of stokers, coal passers, ash handlers, etc. 3rd. For equal heat value, oil occupies very much less space than coal. This storage space may be at a distance from the boiler without detriment. 4th. Higher efficiencies and capacities are obtainable with oil than with coal. The combus- tion is more perfect as the excess air is reduced to a minimum; the furnace temperature may be kept practically constant as the furnace doors need not be opened for cleaning or working fires; smoke may be eliminated with the consequent increased cleanliness of the heating surfaces. 5th. The intensity of the fire can be almost instantaneously regulated to meet load fluctua- tions. 6th. Oil when stored does not lose in calorific value as does coal, nor are there any difficulties arising from disintegration, such as may be found when coal is stored. 7th. Cleanliness and freedom from dust and ashes in the boiler room with a consequent sav- ing in wear and tear on machinery; little or no damage to surrounding property due to such dust. The disdavantages of oil are : 1st. The necessity that the oil have a reasonably high flash point to minimize the danger of explosions. 2nd. City or Town ordinances may impose burdensome conditions relative to location and isolation of storage tanks, which in the case of a plant situated in a congested portion of the city, might make the use of this fuel prohibitive. 3rd. Unless the boilers and furnaces are especially adapted for the use of this fuel, the boiler upkeep cost will be higher than if coal were used. This objection can be entirely obviated, how- ever, if the installation is entrusted to those who have had experience in the work, and the opera- tion of a properly designed plant is placed in the hands of intelligent labor. SIZE OF STACK REQUIRED FOR OIL BURNING BOILERS The cross sectional area of stack for an oil burning boiler need be only 60 per cent of that required by the same plant burning coal. This may be shown by a simple calculation. The composition of a semi-bituminous coal is approximately C = .85 11= .06 ash, sulphur moisture, etc. .09. Fuel oil is made up of C = .84, H = .12, S. N. O. and moisture .06. The air for coal = 11,5 x .85 + .06 x 34.5 = 12.34 lbs.; allowing 50 per cent dilution in order to get air to all parts of furnace gives 18.51 lbs. For oil 11.5 X .85 + .12 x 34.5 = 13.86; allowing 20 per cent for dilution gives 16.63 lbs. As the heat utilized by the boiler from a pound of coal is about 10,000 B. T. U., while that taken up from a pound of oil is about 14,800 B. T. U., it is evident that 1.48 lbs. of coal would be required to furnish the heat absorbed from one pound of oil and consequently the weight of gases from the coal fired boiler would in comparison with the oil be as 1.48 x 18.51 = 27.39 is to 16.63, which means that the same stack will with oil fired boilers have 1.65 the capacity of coal fired boilers. Many plants which are overloaded, which have insufficient chimney area and in which there is not room for the installation of mechanical stokers with forced or induced draft fans, have adopted oil burning. 16 NOTES ON POWER PLANT DESIGN ECONOMIZERS Economizers are made up of cast iron tubes 4" to 4J^" inside diameter and 9' long. The tubes are turned at the end to a slight taper and are forced into top and bottom headers by hydraulic pressure. These headers are made to take different numbers of tubes, as is shown by the table of dimensions given on pages which follow. The lower headers project through the brick work housing and are joined together by a "bottom branch pipe" running lengthwise of the econo- mizer. This "bottom branch pipe" has on one side, a series of flanges for making the connection with the bottom headers and on the opposite side, in line with each header, a hand hole through which the header may be cleaned. The feed water enters this "bottom branch pipe" at the end of the economizer nearer the chimney and leaves the economizer at the top, at the end nearer the boiler. The top headers are similarly connected. This pipe joining the top headers is placed above, instead of at the end of the header, and at the opposite side of the economizer. In some cases means are provided for washing out the bottom headers, by sending a stream of water from a hose down through the tubes at the back end of the bottom headers and letting it flow along the entire length of the bottom headers and out through the clean-out openings directly opposite the headers. In setting up an economizer, room should be left opposite these clean-out openings so that a scraper can be put into each header to remove any scale which may lodge there, as the headers are sometimes cleaned out in this way instead of by washing out. In order to repair a tube and replace it by a second tube without dismantling that section or that header, a slot is made in the upper end of the tube with a chisel so as to enable the tube to be sprung together. The tube is then withdrawn from the bottom header in the following manner : A piece of iron shaped as shown by the accompanying sketch is pushed down inside the tube and moved to one side so as to engage the bottom end of the tube, this piece being held by a rod with thread and nut at the top. A second piece like a wedge, is held against the first piece by a second rod and prevents any side motion of the first piece. By screwing on the first nut the tube may now be withdrawn from the bottom header. The new tube is now inserted, driven into the bottom header, and a conical wedge used to make the joint between the tube and the top header. Sometimes a tube which has given trouble may be plugged and cut out of service. As the tubes are withdrawn through the top of the economizer, or in case of serious mishap, the entire section is taken up through the top of the economizer, — there should be sufficient room left over the economizer to allow for this. The arrangement of the brickwork should be such as to enable a section to be withdrawn without making it necessary to take down a large amount of masonry. The heating surface needed may be put either in one large economizer, through which all the gases from all of the boilers pass, or there may be a number of smaller economizers known as "unit economizers," one for each battery of boilers. With the first arrangement, any accident to the economizer which might put it out of service, would reduce the power of the boiler plant 10 or 15 per cent. The draft would be reduced to a considerable amount by this arrangement. In the second arrangement, as only one unit would be cut out, in case of accident, the reduction in power of the boiler plant would be inappreciable. The flue gas leaving the boiler should have a direct passage to the chimney around the econo- mizer. Suitable dampers should be provided so that the gases may be sent either through the economizer or directly to the chimney. When the economizer is out of service both dampers at entrance and exit to the economizer should be closed. In general, an economizer will save from 8 to 15 per cent. In figuring whether the saving is going to pay for the interest on the first cost, and for the depreciation, the saving to be made in any particular case has to be taken into account. The life of an economizer is generally considered to be 20 years, and the cost set is generally taken as about $4.50 per boiler horse power or $10 to $12 per tube erected. This latter figure does not include an induced draft-outfit which if installed would add to the cost. Reducing the temperature of the flue gas by passing it through the economizer reduces the draft practically in the proportion that the absolute temperature of the flue gas is reduced. The NOTES ON POWER PLANT DESIGN 17 draft is still further reduced by the friction of the gas in passing through the economizer and in the many instances where the draft is poor, it would be unwise to install an economizer unless an induced draft fan were to be installed also. Usually on the side of the economizer there is a space about 12 inches wide left between the last tubes and the casing or brickwork, to allow of inspection. Sometimes there are two such passages, one either side of the economizer. These passages are closed by side dampers when the economizer is in use. Provision should be made for removing the soot from the bottom of the economizer. To remove the soot which collects on the tubes, scrapers are provided, these scrapers being in the form of loose collars which are alternately raised and lowered by chains operated from a shaft run- ning along the top of the economizer. If the economizer is only eight tubes wide, one shaft will serve, but if the economizer is ten or twelve tubes wide there should be two sets of shafts. In place of the brickwork walls a sectional covering of steel bolted together through angle irons may be used. This covering is insulated by building it up of two steel plates with 2" of magnesia or asbes- tos as an insulating material between. The economizers must each be provided with a relief valve of sufficient size, and with a blow- off valve. Various arrangements of economizers as appUed to different types of boilers, and the various arrangements of the direct flues may best be seen by studying some of the cuts of power stations or by referring to some of the cuts shown on later pages. The economizer is always connected on the feed line in such a way that the feed may be by- passed around the economizer, and when the economizer becomes steam bound it should be cut out and allowed to cool until the steam has condensed. The rise of temperature of the feed-water in an economizer may be calculated as follows: Th = temperature of flue gas entering economizer. Tc = temperature of flue gas leaving economizer. th = temperature of feed water leaving economizer. 18 NOTES ON POWER PLANT DESIGN tc = temperature of feed water entering economizer. .24 = specific heat of flue gas. 30 = number of pounds of water fed per boiler H. P. 24 = pounds of flue gas per pound of coal. 9 = probable evaporation of water per pound of coal. {Th - Tc) X 24 X y X .24 = 30 (th - ic) Tc= Th- 1.562 {ih - tc) For different evaporations or for different weights of flue gas per pound of coal the value to replace 1.562 may be easily figured. S = square feet of heating surface in the economizer per boiler H. P. or per 30 lbs. of feed water fed per hour. 3 = B.T.U. transmitted per square foot of surface per hour per degree difference of tempera- ture between the gases outside the tubes and the water inside the tubes. As the coldest gas is at that end of the economizer at which the cold water enters and the hottest gas at the end where the water is hottest, there can be but little error in taking the difference of the mean tempera- tures of the gas and of the water. 30 ih - Q = (^^^ - -^^) xSxS _ 20 tc + 2 S Th + .562 S h ^~ . 20 + 2.562 S The Green Economizer Company use the following formula: S (Th -tc) th-tc = (5w +GC)S ^ + 2GC In this w = pounds of feed water per boiler H. P. G = pounds of flue gas per pound of combustible. C = pounds of coal per boiler H. P. hour. This formula is practically the same as the one already worked out. Example Flue gas leaves the boiler and enters the econpmizer at 550°F. The feed water after passing through both a primary and a secondary heater enters the economizer at 200° F. What is the tem- perature of the feed water leaving the economizer? What is the temperature of the flue gases leaving the economizer? It is customary to provide from 3.5 to 5 sq. ft. of heating surface in an economizer per boiler H. P. Assume in this case 4 sq. ft. 20 X 200 + 2 X 550 X 4 + .562 x 4 x 200 '"' 20 + 2.562 X 4 th = 292° Tc = 550 - 1.562 (292 - 200) = 407° The feed water is heated from 200° to 292° by the economizer. Suppose the boiler pressure car- ried in a battery of boilers to have been 164.8 lbs. ab. with 100° superheat, then theheat needed to make a pound of water at 200°' F. into superheated steam of pressure and conditions specified is 1252 -168= 1084 B.T.U. NOTES ON POWER PLANT DESIGN 19 92 The economizer saved 92 B. T. U. per lb. of water or ^ = .0849 say 83^ per cent. On a coal consumption of 592 tons per week with coal at $4.20 per ton a saving of 83/^ per cent amoimts in the course of a year to .085 X 592 X 52 X $4.20 = $10,989 The economizer consisting of 672 tubes cost at $12.00 a tube, $8,064; the piping etc. brought the cost up to $10,000. There should be charged against the economizer which may be assumed to be worn out in 20 years, a certain percentage for depreciation (see later pages) which we will take as 3.02 per cent, interest 5 per cent, taxes 1.5 per cent, insurance 0.5 per cent and repairs 2.5 per cent making a total of 12.52 per cent. .1252 X $10,000 = $1,252 The saving apparently amounts to 10,989 - 1,252 = $9,737 per year. If an induced draft had to be maintained there should be charged against the economizer the cost of running the fan and the interest, depreciation, etc. on the cost of the outfit. This would make the saving less. In spite of the fact that figures show a decided saving made by the use of an economizer many engineers will not recommend their installation. Some arrangements of economizers follow: The resistance offered to the flue gases by an economizer amounts to from .25" to 30" of water. In many instances on account of this loss of draft, it becomes necessary to install an induced draft fan. Illustrations of induced fan cutfits as erected in two manufacturing plants are shown. 20 NOTES ON POWER PLANT DESIGN GENERAL DIMENSIONS OF GREEN'S IMPROVED FUEL ECONOMIZERS Height over gearing, 13 ft. 514 in. Height over section, 10 ft. 2l^ in. in ">. Dimensions Inside Area Between Xi 3 .0 3 Walls Tubes c ™ s h H ^ ai fc. It n c _ *^ "0 J3 "0 Xi (^ 3 »\ 1 j=3 E § 2 ^11 ^•0 a u S. ^=.■2 E = 5 £ E B c - (fl ^ " ^ rt -•« i .-« n .;: UJ (- a: Z) H CO u. O IT) N C/5 Q < a z < cn to Z < 1 X 1 .. c C r i;......,... ^-■rsisirsssis .^. .. . ...^ : :3;;ss25s=»3 O 2 u J,. = -. = = ..-, = = ------ .,.......i J < U z o ?— — =■— = ' — -=::. = = : = = -- = ^ f ' 1 1 Til Ml 1 Tm .J - N -^rvO C>« TfvO Ov- rOvOOO -\0 - --J-Onp) r--0 ^O moo - On N r^ "^0 '*100 — vO — tT lUUUiUli r^O "^O <^oO —NO ■-' -^O**^ OOOvO -^N OCOMD -^ci OOO rf-O-r^-* — CO rr — cO'"^^^co <^\0 00 — ■^'O O M "* r^ O c) 1- rococo O M "^ r^ O — -^-O o ^ NO - vo r-i r^ M p^ CI 00 r^oo ON r-oO w^ — 00 On\0 r^ -v lo ONr^TTfi 000 w^fo- o^no -a- ■V r- *^NO 00 — -^ 1^ ON CI *^ f I OM^ Tf - CO ^ ri ONNO M t^ Nooo - rrr^ONM i>-tr-.o myj CI CI ror^c^'^'^'^'^^^'^rp rONO On CI u-tCO — 'T t-^ Q ^nO c^ m CO TT rr tT "^ "-) 'OnS ^0 ^ 1 External Healing Surface. Sq. ft M M rr^ c^ -rf -^ tf tJ-i irj\0 ^ r>. TfMOO Tf — CO "-iciOO iJ^N o^o CO oo r^ r-^ t^NO vO nD tn u-) t>^ Tt- -^ TrcN-^ONrroNTro^-^ONTfON-^ rt M n-) rn -^ "^ "^ u-)\0 NO t^ r^OO U-) « 00 Tf — NO <^ 0^'^ M On u-1 - \0 Ln -T ON r^oO ro r^ N On^ io-\0 - r^MOO <^0> ■^ u-vso NO r^ rN.cO 00 On On O O 1 Csu->— r^r^ON^O— r^ "^^ ON >r^i Tr-^Tpcoc^ft CI tfi — — oo\o vn— i^coOniO— r^c^ON-rfO \0 P^ t^CO OOOnOO — — '^m 'uoipsg Os On On ^N O* O^ on O^ O^ On On On OOOOOOOOOOOOO MC4nMMMr^«'i'^*^(^^ _-.««««^-«-«--« •suoipsg JO O -^00 N\0 O '^OO N nD O -T O --i-oo N NO O "^cO mnO O --tco M ci M rnfO' -"d- ■<*■ -^ Ny-» \r,\0 vO NO r^ t^OO Z%''K3,S^^^f~&^» ■sadij JO jaquinM QvO NOO Tj-ONO MCO Tj-ONO 30 •- ^ooo N NO ON rno o -^ r^ OOOOOOOOOOOOO o -^00 M no o Tfoo N NO o ■3-00 N M PI r^ r^ TT -rr -rt ^^ U-INO \0 NO NO too N NO -^CO N NO On ^00 CI r- - NO ^ ON moo rr^r -^ u-i Loso NO r^ r> r^co oo 10 lAvO vO r^ r^oo CO ON ON 31 JEW O w « CO ^ »o\o t^oo oi O M « « ^ into t*.fio tf» M « m ^ irtio t>oo 01 M CJ fO^ V>JD t>. C- ci. C^CO 00 op 00 00 CO CO £-s8.s.asss"a&?. ui z a z < H X X 1« 11 So T- = =-= = - = :.: = = :: = :-. - -- -- « Z s .2 S ............ a < OS Id Z w ■ ■3 l^= = = = = = = : - T — — — — — LO ^ 2.=...==.==. ■5 = B C^OO - NO — T COCO — NO — ■^ ON CI T MM 1 1 I 1 1 1 1 I 1 II ■* r^ ON CJ ^0 ON Tj- t^ ON CI TTO Cn — TT rocO "NO - TTOCI V^ r^. On PI ■TNO ON — ttno On 00-0 - -j-CN r^0"^0 On PI "TNO on— -^TNO On ■- CO CO -0 - ttOnn ts,i tno 00 pi -t CO -TNO r^CO ON Q CI ro -^ 1^0 w^O n/^OnO -no - Tf nO r*. On ci ro iy->\o 00 NO -3-00 M NO "^00 p^ NO tOPico -T— r^-^ONO coOn OOOloco — COnO ■^'-' OnnO r^co PI ■^Lor^ON— ^^ t1- 8064 10080 12096 14112 16128 18144 20160 22176 24182 26198 28224 30240 External Heating Surface. Sq. ft. lllllll On 0^ onco 0^ r^ r^ r^O o^-ro^-q-o-rro^TO^ -rr^ONCi -(rr^ONN tt r^\0 nOui-3-coci h- On OnOO^OnO'O'O^On OnCO 00 — 'T f^ COnO On M to «««NMC|MCOro TT CO PI ON P^nO "-> CO M On -T o^ Tco cooo COCO moo en r-. Ti- r-v - Tf CO - t^co 1- - P4P^ CI romcOTr-<3--T i 0^ 000 cooooooo i^r^r^i^r^ •uotpss Dl SSdt J JO 'OK Tj- TT rr Tf -rr TT -d- nOOnOnOnOnOnOOnOO cocccooocoooccoooooooooo ■SU0l»D3S JO 4aqainfj 00 CI NO -rco CI - - N n CI ro CO CI NO -TCO CI NO - - Cl M CI .CO CO TT PI -^00 Ct NO -TCO NO -rrCO fl NO •'l-OO PI NO --NN ►- N en TT u-no t^ 00 0^ - « *n ■* «mo t^oo o» N M w tn tri rri " ,^ ^^y^ 250 -'' '-'' ^^ / ^,'' ^ y ^ y .'' 230 ^'' ,.-'' ^ ,' .^ >> X ,^ -^ -'■ *' -^ a a g210 ■4-* ^^. ^f- " / ^ y ^x .A ^ ^ ^ ^^ P-190 u ^' A X ^^ / y / 'c^ ^ y^ a. 1 170 y • ^ ^ y > ,/' ^ ^ r y • y X 150 y y y ,,;; y *» ^ '^ 130 y *■ y 90 110 .130 150 170 190 210 Height of Chimney 230 250 270 290 With Taylor or Riley underfed stokers the air is delivered through the fuel bed under pressures of 4" to 6" of water, whatever may be needed to maintain a balanced draft over the fire; the stack is by this means relieved of the resistance offered by the fuel bed and generally gives sufficient draft to pull through an economizer. The gases after leaving an economizer are cooled and the draft of the chimney reduced because of the lower temperature. It will be found that adding 25 feet to the height of a chimney does not increase the draft very much. The dimensions of a chimney may be found with as great accuracy as is required by means of a chart which has been constructed from the tables of H. P. of chimneys given by Kent and NOTES ON POWER PLANT DESIGN 29 by Christie (See Steam Boilers, Peabody & Miller). On this chart the capacities in lbs. of coal per hour per square foot of chimney area are given for different heights of chimney. Knowing the coal to be burned per hour, the cross sectional area for any assumed height may be calculated. The ratio of height to cross section must be considered, otherwise a poorly proportioned chim- ney may be obtained. For discussion of the stability of a chimney see Steam Boilers. In general the maximum com- pression due to both dead load and wind pressure is not allowed to exceed 10 tons per square foot. FEED PUMPS FOR BOILERS STEAM CONSUMPTION OF PUMPS The steam consumption of a duplex pump varies with the speed at which the pump runs. At half speed or at one-half rated capacity 125 to 150 pounds of steam will in general be re- quired per horse power hour of water work done. For slower speeds the rate may become as large as 200 or 250 lbs. At full speed and at rated capacity 90 to 100 pounds is a fair value to use for the steam consumption per water horse power per hour. Turbine driven centrifugals are now quite generally used as feed pumps in the larger power plants. The efficiency of a centrifugal pump designed for a given head and given capacity may reach 80 per cent, but under the conditions which apply to centrifugals used as feed pumps a value between 40 and 55 per cent should be used. The steam consumption for the driving end may be obtained from the curves already given. Drawings and table of dimensions of the Terry steam turbine with centrifugal feed pump are given on page 39. 30 NOTES ON POWER PLANT DESIGN THE KNOWLES HORIZONTAL DOUBLE ACTING PLUNGER PUMP. POT VALVE TYPE. End packed for 300 lbs. working water pressure. Center packed for 200 lbs. working water pressure. Center Packed 4J 2f 6 .11 150 16.5 i 1 n 1 68x10 4J 23 6 .15 150 22.5 i 1 n 1 68x10 5J H 7 .25 125 31. i 1 2 n 72x12 G m 7 .33 125 41. 1 L 2 n 72x12 6i 4J 8 .46 125 57.5 ? li 2% 2 75x12 n 4i 10 .69 100 69. 1 u 2* 2 89x14 8 5 10 .85 100 85. 1 u 3 2h 89x14 8 5 12 1.02 100 102. 1 n 3 2\ 96x14 10 6 12 1.47 100 147. n U' 3^ 3 98x22 12 7 12 2.00 100 200. 2 2h 5 4 100 X 27 14 8 12 2.61 100 261. 2 2* 5 4 102 X 27 16 9 18 4.96 67 332. 2h 3 8 6 136 X 30 End Packed ■a o -3 £ E -g r si PI Capacity per Minute at Maxi- mum Speed a. a S g a 1" t a A 1" ES|S OS a " u Strokes Oal3. 4 24 5 .11 150 16?s * 1 u 1 57x10 5i 3J 7 .25 125 31 I 1 2 14 72x12 6 31 7 .33 125 41 I 1 2 14 72x12 7i 31 10 .47 100 47 li 2 14 92x12 n. 4* 10 .69 100 69 u 2i 2 92x12 8 5 10 .85 100 85 u 3 24 92x12 8 4 12 .65 100 65 u 2i 2 112x12 8 5 12 1.02 100 102 u 3 24 112x12 10 5 12 1.02 100 102 U n 3 24 112x12 10 6 12 1.47 100 147 U n. 34 3 112x22 12 6 12 1.47 100 147 2 2h. 34 3 114x22 12 7 12 2.00 100 200 2 2* 5 4 120 x 27 14 7 12 2.00 100 200 2 2h 5 4 120 X 27 14 8 12 2.61 100 261 2 2h 6 5 124 X 27 16 8 12 2.61 100 261 2\ 3 5 4 124x28 16 8 18 3.91 67 261 2\ 3 6 5 164 X 30 16 9 18 4.96 67 332 2\ 3 8 6 164x30 18 9 18 4.96 67 332 2i 3 8 6 172 X 30 In an emergency the capacities of these pumps can be doubled. For continuous work such as boiler feeding, speeds and capacities one half of those given are recommended. NOTES ON POWER PLANT DESIGN 31 THE VENTURI METER Nearly every large power plant has a Venturi meter in the boiler feed pipe. This meter may have a recording indicator or simply a Venturi meter manometer. The table following gives the sizes of the meters for boiler feed pipes as made by the Builders Iron Foundry of Providence, R. I. The Venturi meter manometer contains a well filled with mercury into whichaglasstubedips. The higher pressure from the inlet of the Venturi is conducted to the top of the mercury surface, and the lower pressure from the throat of the meter to the interior of the glass tube. The difference in these two pressures is indicated by the height of the single column of mercury within the glass tube. The rate of flow for any difference of pressures can be read opposite the surface of the mer- cury of the inner tube from the graduated scale shown at the left. The total quantity of water flowing may be obtained by taking readings periodically, averaging the same and multiplying the average by the elapsed time. The manometer is not suitable for installations where the rate of flow changes rapidly. For such cases the recording indicator shown would be preferable. Extra heavy meter tubes with "Manufacturers Standard" flange ends are usually selected for hot water. These are adapted to pre sures'up to 250 pounds per square inch. Inches D-iameter of Pipe Catalog Number Length of Meter Tube Boiler Horse Power 30 lbs. per H. P. pel hour Pounds per Hour Gallons per Minute Mininiuni Maximum Mlomum Maximum Mlmmum Manmum 2 2^8 21 r-ii^s" I'-lOX" l'-7" 45 65 115 590 850 1500 1360 1960 3470 17600 25400 45100 35 50 90 T^ 2J^A 2KB 2KC 2'.45/8" 2'-3" 1'.113^" 85 115 180 1150 1500 2350 2660 3470 5420 34500 45100 70400 11 70 90 140 3 31 31^ 2'-ll" 2'-73^" 2'-4>^" 115 180 260 1500 2350 3380 3470 5420 7820 45100 70400 102000 11 16 90 140 205 4 41^ 41 H 42 4'-33/" 3'-10%'' 3'-6" 180 305 465 2350 4000 6000 5420 9170 13900 70400 119000 181000 11 18 28 140 240 360 5 515/8 52 52'/ 5'- 13^" 4'-8'/i" 4'-2" 305 465 725 4000 6000 9400 9170 13900 21700 119000 181000 282000 18 28 45 240 360 560 6 62 63 5'-ll" 5'-4// 4'-IO" 465 725 1040 6000 9400 13600 13900 21700 31300 181000 282000 406000 28 43 63 360 560 810 680 950 1440 8 82K 83 K 84 7'-6K" 6'-ll3,," 6'-2" 870 1230 1850 11300 16000 24100 26500 36600 55600 344000 476000 722000 53 73 111 10 103 -i 104 105 9'-434'' 7'-6" 1230 1850 2900 16000 24100 37600 36600 55600 86900 476000 722000 1129000 73 ill 174 950 1440 2260 12 124 125 126 11 '-0" 9'-ll" 8'- 10" 1830 2900 4200 24100 37600 54200 55600 86900 125000 722000 1129000 1626000 111 174 250 1440 2260 3250 32 NOTES ON POWER PLANT DESIGN Glass Tube Graduated Scale Float O CHART RECORDER DIAL (Continuoash' records the rate of flow) INDICATOR DIAL (Shows the present rate of flow) DI:MENSI0NS, Etc. Base — 16 inches square Height — 6H feet Shipping Weight — 500 lbs. NOTES ON POWER PLANT DESIGN 33 CALIBRATION TESTS ON METERS IN SERVICE Test No. 1. Made at Worcester Polytechnic Institute on 4-inch meter tube No. 2319, 1^ inch throat, equipped with manometer. Water was pumped through the meter tube into a verj' large wooden tank resting on platform scales, which form a part of the regular laboratory equip- ment. The manometer was placed on the floor immediately below the meter tube to which it was connected by flexible pipes. The rated capacity of this meter is 9,170 to 119,000 pounds per hoiu". The results were as follows: Numbers Pounds of Water Per Hour Error of Meter of Tests Meter Manometer Actual W'^eight Manometer 1 120,600 122,640 - 1.87% 2 90,000 89,820 + 0.20% 3 59,950 59,940 + 0.02% 4 and 5 30,000 29,370 + 2.10% 6 and 7 9,000 8,950 + 0.55% Test No. 2. Four-inch Venturi Meter (134-inch throat) at the plant of the Woonsocket (Mass.) Electric Machine & Power Company. Wtter pumped by duplex feed pump to two bar- rels which were filled alternately, the weight of water which each would hold having been deter- mined previously. The test lasted five hours and the flow was continuous. Corrected weight of water by barrels ..... 132,802 lbs. Corrected weight of water by Venturi . . . . . 131,000 lbs. Difference, 1.35%. Test No. 3. Four-inch Venturi Meter (134-inch throat) at plant of Brown & Sharpe Mfg. Company, Providence. Meter Tube was located on suction side of single plunger pump and course of water was from two calibrated open heaters (emptied alternately) to Meter Tube to pump. Total pounds of water by heaters ...... 392,453 lbs. Total pounds of water by Venturi Meter .... 397,104 lbs. Difference, 1.18%. Duration of test, 10 hours. A paper prepared by Prof. C. M. Allen presented before the A. S. M. E. gives a full discus- sion of the Ventiu-i Meter as applied for measuring feed water. 34 NOTES ON POWER PLANT DESIGN ENGINES STEAM CONSUMPTION OF ENGINES The steam consumption of a simple non-condensing engine varies both with the cut-off and ^^ ith the boiler pressure. There is but little gain in raising the pressure on a simple engine above 150 lbs. The variation in steam consumption per I. H. P. hour with the cut-off may be figured with reasonable accuracy from the full load consumption by multiplying the full load consumption by the following ratios: Load ^ 3^ M Full IVa Ratio 1.26 1.13 1.09 1 1.05 From tests on engines, of about the same type and size as the engine under consideration, working through the same ranges of pressure and temperature, from the same initial conditions, one can predict the probable performance with reasonable accuracy. In the absence of such tests the cylinder efficiency of a single valve non-condensing engine working with steam under 150 lbs. absolute may be taken between 55 and 65 per cent, when work- ing at its economical load. The cylinder efficiency of a four valve condensing engine may be taken at most economical load as from 66 to 72 per cent. The size of the engine, the valve gear, etc. all have an influence on the so-called "cylinder efficiency." This cylinder efficiency multiplied by the Rankine efficiency and by the mechanical efficiency gives the overall efficiency from which the steam consumption may be calculated as explained later CALCULATION OF POWER OF ENGINES The mechanical efficiency of an engine or the ratio of the brake power to the indicated horse power is between 90 and 93 per cent. The power of an engine at any speed and cut off may be found by drawing an indicator card using hyperbolae for expansion and compression lines, getting the M. E. P. from the card and then proceeding in the usual way. For a compound or triple expansion engine the M. E. P. is calculated on the assumption that the entire pressure drop is to be obtained in the low pressure cylinder. The ratio of cylinder volumes is for compound engines H. to L. 1 to 23/^ or 3 in some rare cases 1 to 7 or 8 for triple expansion engines H. to I. 1 to 3 I. to L. 1 to 3M or 33/^ or H. to L. 1 to 93| or lOj/^. A calculation for Horse Power, which will give results more or less in error depending upon the accuracy with which one knows the multiplier used in getting the actual M. E. P. from the calculated, may be made as follows: — Calculated M. E. P. x multiplier x J^ X .7854 x 2 x Revs, x S ^ •" 33000 D = dia. low pressure cylinder in inches Revs. = revolutions per minute Pi = absolute initial pressure on a square inch P2 = back pressure absolute on a square inch N = No. of expansions = 77- — ^ ^ H^xcutoff Cut-off is expressed as a decimal. NOTES ON POWER PLANT DESIGN 35 S = stroke in feet H = dia. high in inches Calculated M. E. P. = -^+-^2.3026 %io N - Pi CYLINDER EFFICIENCY OF STEAM ENGINES AND STEAM TURBINES The ratio corresponding to the cylinder efficiency is for condensing turbine units about the same {%. e., .60 to .72) as for condensing steam engines; for non-condensing turbine units, however, the ratio is much lower than for non-condensing engines, the value being .40 to .49 as against .55 to .65. The higher the back pressure the lower the ratio becomes and .40 would apply for pressures of 50 to 70 lbs. absolute back pressure, .45 for back pressures about 35 lbs. absolute, and .49 for back pressures of 15 to 20 lbs. absolute. From these figures it is at once evident that the non-condensing turbine working against back pressure cannot compete in economy with the better class of non-condensing reciprocating engines. It is the custom in many manufacturing establishments to bleed steam from some stage of a turbine or from a receiver between the cylinders of a multiple expansion engine and to use this steam for industrial purposes. This is done rather than to draw live steam from the boilers through a reducing valve. It is also customary where there is a surplus of exhaust steam coming from the auxiliaries or in other words more steam than can be condensed in heating the feed water in a secondary heater, to exhaust this surplus into one of the low pressure stages of the turbine or into the second receiver of a triple engine and to thus get additional work out of this waste steam. Where steam is bled in this way a valve has to be provided to prevent steam from getting back into the turbine through the bleeder opening and causing the turbine to run away when under light load, at which time, boiler steam taken through a reducing valve would be fed into the bleeder Jine to supply at reduced pressure the steam needed for industrial purposes. RANKINE EFFICIENCY AND CYLINDER EFFICIENCY A simple calculation for a bleeder turbine with steam withdrawn at one of the higher stages and having the exhaust steam from the auxiliaries sent back into the low stage will serve to illus- trate the method of getting the steam consumption. Assume : 2000 K. W. output at switchboard. Mechanical Efficiency of Turbine, 92%. Generator Efficiency, 93%. 9000 lbs. steam bled out per hr. at 36 lbs. abs. 2000 lbs. exhaust steam per hr. with 1.7% moisture put back at 15 lbs absolute. What is the steam consumption per K. W. hour with boiler pressure 177.5 lbs. ab. 97.3. Sup. and 1 lb. absolute pressure in condenser? Making use of a temperature entropy plot or diagram, the values maj'' be tabulated as below. Press, ab. Quality Entropy Heat Contents Heat of Liquid H q 177.5 97.30 Sup. 1.62 1.252.2 36 .95 1.62 1120.6 230 1 .807 1.62 904.8 70 15 .983 1.73 1133.6 181.3 1 * .867 1.73 966 6 70 36 NOTES ON POWER PLANT DESIGN Rankine eff. =—^7 Hi- qi Hi - Hi = {Hi - gs) X Rankine Eff. = heat put into work per pound in non-conducting engine. {Hi -Hi) X cylinder eff. = heat per pound of steam actually put into work. 1252.3 - 1120.6= 131.7 131.7 X .45 X .93 X .92 = 50.7 .45 = cylinder eff. „.._ 33,000x60 2545 =— 7y8— 2545 X 1000 50.7 X 746 = 67.3 lbs. steam per K. W. hour between 177.5 and 36 lbs. ab. -Fn~o = 133.7 K. W. developed by the steam before it is bled. 1133.6 - 966.6 = 167 167 X .50 X .93 X .92 = 71.4 A. cylinder efficiency of .5 has been used because of the moisture in the steam 2545 X 1.34 71.4 _2000_ 47.76 = 47.76 lbs. steam per K. W. hour between 15 lbs. and 1 lb. absolute. = 42.0 K. W. recovered from exhaust put back at 15 lbs. ab. 1252.3 - 904.8 = 347.5 347.5 X 63. X .93 x .92 = 187.3 ■ 2545 X 1.34 ^ ^g_21 187.3 2000 - 133.7 - 42 = 1824.3 1824.3 X 18.21 = 33,220 Steam bled = 9,000 Total steam to turbine from boiler = 42,220 Total steam to condenser = 33,220 + 2,000 While it may be allowable to use a ratio higher than .63, in this case .63 is conservative. Although efficiency ratios as great as 71.8 have been obtained, in general the ratio actually realized on the commercial machine is lower. By the addition of extra wheels in a stage or of extra stages it is possible to get the high ratios quoted, as the loss from leakage by the blades is thereby reduced, at the same time however the cost of the turbine is increased and it becomes a question as to whether or not the better economy warrants the extra expenditure due to the increased first cost. For low pressure turbines the efficiency ratio for machines of 50 to 75 K. W. capacity is between 50 and 55 per cent. A paper read by Mr. Francis Hodgkinson before the A. S. M. E. gives the steam consumption of Parsons Turbines under different conditions of pressure, superheat and vacuua. As this data may be found useful the table has been reproduced here. SSSi :*- : :S2- :» SS5 :« 5Slg in as : • Sc3 S5 .t: M i :i| is 8 ■ •« c5 KR3 :i- K? cooeo =.S :? SS :S5 : ;='3 : 153.5 27.0 2.0 3,583 i ill 1 " Si ss' i| : :ss ■"■ s s 148.3 27.0 6.0 3,563 g 5t-e- ;•?)_ 30 -O-^ • • ■— -eo «o -oa SS". :g- : Sg :g8 "Si" 5S S5S ■■' :-«■ SS :a 149.8 4.0 ■3,59a i iiS 15 ' ,§0 .§ 6,916 77 » :S? s§ : •" i :2t . ■- iftO 5§' :S| . -O-H :S 3 00 5S : Igg ■■£ S ka : :3S 5S : "w o fc « Mo 2 ■ Jj-rxl ; : : : :S.S . -00 :•= i « tt S; -ja 5 w *■ 0- SE« Eii'OCo 6; 32*3 .SB ) « a ^ S ^d S S ' o e Q •sa a s;: 5S?S S iis is -- S--iS-2 SsS ;::- S8 :"-2 ^^iS^ ~5 :«S II 152 :S= ■"' "5 Is- ss eS :«£; •:- || :g-: Si;|! ■dS •sgs •sg ;ss ssss 'is- •ss- i ° .s. ? "SS.'aS — — ^^^ 0000c J,JHB> c SE Reference Q 2128 rt a: Eh > O l^A cp X X H Erste Briinner M. F. G Curtis-Parsons 1910 1500 156.2 482 27.89 0.995 1 13.82 16460 247.0 343.8 71.8 Periodische Mittcilungen Erste Brunner M. F. G Curtis-Parsons 6000 960 184.9 573 28.18 0.854 12.56 15570 271.5 380.7 71.3 Zeit. D.V.D. Ing., 12/10/'10 Erste Brunner M. F. G Curtis-Parsons 1910 7442 960 192.0 584 28.18 0.853 12.625 15705 270.2 384.4 70.3 Periodische Mitteilungcn Westinghouse Machine Co. Curtis-Parsons 1910 9173 1800 181.7 433 27.81 1.032 14.57 16925 234.1 340.2 68.9 Trans. A.S.M.E., vol. 32 Brown Boveri & Cie Curtis-Parsons 3053 1360 150.2 505 29.00 0.456 13.01 15990 262.2 385.5 68.0 Dinglers P.J., 6/17/'ll Erste Brunner M. F. G Curtis-Parsons 1910 1416 1260 128.2 482 27.60 1.137 15.18 18060 224.6 326.5 68.8 Periodische Mitteilungen Brown Boveri & Cie Curtis-Parsons 1911 1750 1500 176.4 586 27.08 1.392 14.23 17500 239.5 354.8 67.5 Zeit. F.D.G. Turb., 5/30/'ll Brown Boveri & Cie Curtis-Parsons 1910 3764 1500 161.2 561 28.77 0.562 13.04 16290 261.5 391.4 66.8 Zeit. F.D.G. Turb., 5/30/'ll Westinghouse Machine Co. Curtis-Parsons 9830 750 192.2 475 27.22 1.322 15.15 17790 225.2 336.0 67.0 Trans. A.S.M.E., vol. 32 Brown Boveri & Cie Curtis-Parsons 1911 1495 3000 200.6 563 26.41 1.720 14.78 17880 230.7 345.5 66.8 Data from Manufacturer Brown Boveri & Cie Curtis-Parsons 1911 1271 3000 172.1 568 27.31 1.278 14.61 17880 233.5 354.3 65.9 Data from Manufacturer Westinghouse Machine Co. Curtis-Parsons 11466 750 191.7 484 28.07 0.910 14.45 17210 236.0 360.5 65.5 Trans. A.S.M.E., vol. 32 Erste Brunner M. F. G Curtis-Parsons 1250 3000 184.9 573 27.89 0.996 14.32 17680 238.2 373.1 63.9 Zeit. D.V.D. Ing., 12/10/'10 Brown Boveri & Cie Curtis-Parsons 1910 3320 1500 180.9 525 29.02 0.440 13.50 16680 252.7 401.3 63.0 Zeit. F.D.G. Turb., 5/30/'ll Brown Boveri & Cie Curtis-Parsons 5128 1000 171.2 565 28.52 0.726 14.35 17830 237.7 382.9 62.1 Stodola, 4th ed., p. 449 Breitfield, Danek & Co Impulse-Parsons 1909 3585 896 160.7 457 28.32 0.782 16.08 19070 212.0 352.4 60,2 Zeit. D.V.D. Ing., 12/10/'10 Brown, Boveri & Cie Parsons 1910 6257 1210 203.7 559 29.02 0.440 11.95 14980 285.5 415.0 68.8 Official Test Report Parsons 1908 4300 1800 186.4 484 27.96 0.960 14.02 16690 243.4 355.7 68 4 Sibley Jour, of Eng.. 1/11' Zeit. D.V.D. log., 12/10/'10 Brown Boveri & Cie Parsons 1903 3500 1360 156.4 499 28.84 0.532 13.71 16720 248.5 378.6 65.6 Brown Boveri & Cie Parsons 3000 1360 165.0 625 27.02 1.120 14.75 18433 231.3 359.5 64.3 Die Turbine, 6/20/'ll C. A. Parsons & Co Parsons 5164 1200 214.3 509 28.95 0.473 13.18 16140 258.7 402.3 64.3 Stodola, 4th ed., p. 439 Allis-Chalmers Parsons 1911 3850 1800 164.7 491 27.91 0.983 15.40 18410 221.3 348.3 1 63.5 Power, l/2/'12 " 1 A. E. G Curtis-Rateau 1911 6518 1220 198.7 601 29.28 0.352 11.43 14640 1 298.4 | 434.2 68.7 Official Test Report Official Test Report A. E. G Ciirtis-Ratpau 1911 6565 1220 200.2 597 29.18 n.40R 11.64 14848' 293.0 ' 427.7 68.5 British Westinghouse.. M.A.N Uergnaann Bergmann A.E.G British Westinghouse. A.E.G M. A. N Bergmann Curtis- Curtis- Curtis- Curtis- Curtis- Curtis- Curtis- Curtis- Curtis- Rateeu Zoelly Rateau Rateau ■Rateau Rateau ■Rateau ■Zoelly ■Rateau 1911 1909 1910 1908 1911 1907 1911 5060 3584 1545 2477 4?39 2930 3169 2507 3365 1500 1500 1500 1500 1500 1500 1500 1500 1500 190.2 178.3 188.5 140.0 188.3 210.2 184.7 175.5 171.0 552 569 581 522 662 568 592 460 536 28.68 27.54 28.59 28.81 29.11 28.18 29.11 27.40 26.00 D.649 1.166 0.654 0.588 0.397 0.894 0.397 1.234 1.98 13.00 13.99 12.97 13.93 11.97 13.72 12.74 16.24 15.09 16100 17190 16230 17135 15620 16935 16230 19020 17970 262.4 243.7 263.0 244.8 284.9 248.7 267.7 210.0 234.1 391.5 361.3 396.3 373.4 439.0 383.3 425.1 334.6 381.3 67.0 67.5 66.4 65.6 64.9 64.9 63.0 62.8 68.5 Electrical Review, 6/23/'ll Data from Manufacturer Zeit. D.V.D. Ing., 12/]0/'10 Elec. Zeit., 4/20/'ll Stodola, 4th ed., p. 404 Electrical Review, 4/28/' 11 Trans. A.S.M.E.. vol. 32 Data from Manufacturer Official Test Report James Howden & Son. M.A.N Escher Wyss & Co. . . . Efcher Wyss & Co. ... F. Ringhoffer M. A. N Oerlilion Esther Wyss & Co.... Eacher Wyss & Co. . . . Escher Wyss & Co. . . . Escher Wyss & Co. . . . Escher Wyss & Co. .. . Zoelly Zoelly Zoelly Zoelly Zoelly Zoelly Rateau Zoelly Zoelly Zoelly Zoelly Zoelly 1909 1910 1910 1910 1908 1910 1911 1908 1910 1910 6383 1400 2052 4189 3000 1250 3166 5118 5000 3540 1641 1235 1000 3000 3000 1000 1000 3000 1500 1000 1000 1500 3000 3000 202.7 180.7 193.9 179.7 170.7 182.1 213.9 133.7 166.4 155.1 221.0 176.8 520 554 585 557 470 582 663 549 539 469 672 451 27.33 27.40 28.39 28.66 27.60 28.82 29.25 27.55 26.38 28.21 27.91 28.39 1.269 1.237 0.750 0.618 1.138 0.540 0.367 1.161 1.736 0.838 0.985 0.750 14.305 14.21 13.04 13.30 15.52 13.09 11.44 15.18 16.13 15.07 13.08 15.35 17150 17310 16290 16520 18278 16500 14970 18530 19350 17940 16775 18156 238.5 240.0 261.5 256.5 219.8 260.2 298.2 224.6 211.2 226.3 260.6 222.3 353.0 356.2 392.6 391.3 339.2 404.5 450.6 341.6 330.4 349.5 406.5 357.8 67.5 67.4 66.6 65.5 64.8 64.4 66.1 65.7 63.9 64.8 64.1 62.2 Engineer, London, 10/29/'O9 Zeit. D.V.D. Ing., 12/10/'10 Zeit. F.D.G. Turb., 2/20/'ll Zeit. F.D.G. Turb., 2/20/'ll Zeit. D.V.D. Ing., 12/10/'10 Zeit. D.V.D. Ing., 12/10/'10 Engineering, 10/20/'10 Dinglers P. J., 7/15/'ll Zeit. D.V.D. Ing., 12/10/'10 Dinglers P. J.. 7/15/'ll Zeit. F.D.G. Turb., 2/20/'ll Zeit. F.D.G. Turb., 2/20/'ll British Thomson-Houston Gen. Elec. Co British Thomson-Houston A.E.G A. E. G Gen. Elec. Co British Thomson-Houston Gen. Elec. Co Gen. Elec. Co British Thomson-Houston Gen. Elec. Co Curtis Curtis Curtis Curtis Curtis Curtis Curtis Curtis Curtis Curtis Curtis 1911 1909 1906 1909 1911 1911 1910 2987 3464 2500 3000 2236 8880 1541 10816 5095 1221 8775 1500 1500 1500 1500 1500 750 3000 750 154.7 210.0 126.5 191.3 191.6 192.5 149.7 190.0 185.1 134.7 194.0 505 513 414 590 654 487 365 525 554 448 451 26.75 28.75 28.47 29.05 29.34 28.02 27.97 29.39 29.40 27.16 27.95 1.557 0.575 0.711 0.427 0.284 0.933 0.956 0.260 0.255 1.353 0.956 15.96 13.62 15.92 12.79 11.77 15.05 17.46 12.90 12.71 17.75 15.95 18960 16620 18590 16240 15450 17965 19720 16135 16090 20690 18720 213.7 250.4 214.0 266.6 289.8 226.7 195.3 264.5 268.4 192.2 213.8 321.2 393.4 336.1 420.4 455.8 359.5 320.2 427.3 436.0 ■314.0 350.8 66.5 63.6 63.7 63.4 63.6 63.1 61.0 61.9 61.6 61.2 61.0 Engineering, 10/20/'ll Trans. A.S.M.E., vol. 32 Zeit. D.V.D. Ing., 12/10/'10 Zeit. D.V.D. Ing., 12/10/'10 Zeit. D.V.D. Ing., 12/10/'10 Trans. A.S.M.E., vol. 32 Engineering, 10/20/'ll Trans. A.S.M.E., vol. 32 Trans. A.S.M.E., vol. 32 Engineering, 10/20 ''11 Trans. A.S.M.E., vol. 32 References: Zeit. D.V.D. Ing. — Zeitschrift des Vereines Deutscher Ingenieure; Zeit. F.D.G. Turb. — Zeitschrift f tlr das Oesammtw Tuibinenwesen; Dinglers P.J. — Dinglers Polytechnisches Journal; Elec. Zeit. — Electrotechnische Zeitschrift. Il NOTES ON POWER PLANT DESIGN A 39 Discharge^ £')chausi- Port/a/ £'nd and S/cfe E/ei/af/ons. •5hoiv/nff change /n stsarn connection /n .sizes: — /80-360 Sai. joer min J"^ ^Sfeam 360 -S^O •• £nd and 3/c/e £'/ek'ai-/ons:— 90 -/80 Gcf/.per m. Partial End and Sids Elei^ations, 3 halving change in ^team connection in sizss ■' — S'^O-IZO Sai.permin 720 -i20O " Gcr/. per m in. 90-180 /ao-360 360-S40 540-720 720 -/20C 1) j' 4-k" 9" A a -ig 3--7i- 8'-6^' ll'-9ji" 12' -/O^' i/" 'y£ II" B 2'-S" 2'-S" 3'- 1" 4-'-7" -#•'-7" Exhaust dia. 4" 4" 6" 9" id' C~ ,9i" 2--8f 3'-4-i" K i4' J4-" ei iSg 17" D 2'-///' 3'-z" 3'-6f S'-3^" 4-'-/o" L 22" 23^ 2'-2k" 3-1" 3-1" E 2 '-6/" 2'-'04' 4-'-2f: 4'-oi" i^ < 764:" 78^" 2'-4" 2'-&" F ae" z-^i 24^ 3'-0" 2'-8^' 1 Suction dia. 4" s" s" 6" s" 1 _ Jfeom dia z" z' 3i" ^i" 3S" N 7/ iif iif /&" iSi" 6 6/ O i9i' '&ra ^eg 20" 2'i" G' ^4' '^r '7i' '^i' Discharge dia. 3" 4" 4-" s" 6" H "g" "f '^k- - P ^$ 7^' ^" iof lO" h' 24" 2-3^" Q 'S^" 24'M' ^^.r 2-4,r 3'-Sf J s" P //" i2i" '2s" i6s" 22" 5 ■^-^i" ^'-sM' s-ef y'-'Og 8'-3i' T 23^ ^ - Hb .40% bled r. X % bled %bled (^ 1 - iifc) -TRTT- qh + —TT^TT- tib 100 ' ' "' 100 ^" ' 100 '- — ^^ (Hi -Hb) -I 'TncT' (Hb ~ Ih) which is the difference in the heat supplied by the boiler per pound of steam 42 NOTES ON POWER PLANT DESIGN GENERAL DIMENSIONS OF ENGINES Tables of cylinder sizes, horse power and overall dimensions of a number of different engines are given on the pages following. The engines shown are each typical of a class and have been selected with this in mind only. In general the single cylinder engines are rated on a cut-off at about one quarter stroke. NOTES ON POWER PLANT DESIGN WATER RATES OF SMALL TURBINES 43 The water rates of small turbines, exhausting against atmospheric pressure, based on test are shown by the accompanying plots taken from an Article by G. A. Orrok in Vol. .31 of Transactions of A. S. M. E. 5000-1 10000 120" 160 Brake Horse Power Steam Consumption Cuhves, Bliss Turbine, Non-Condensing 83 100 120 Brake Horse Power TESTED BY F. L. PRTOR AT HOBOKEN, N. /. O = Two-nozzle, X = Four-nozzle 1500 Load CtmvES of Kerr Turbine 24-IN. WHEEL, 8-8TAOB 175-I-B. OAQE PEE88UEE, NON-CONDBNSIN^ 26 38 34^ 39 43X- 46X 4SU 54 57 STA 108X 118 123K 137 K 139 35;^ 38;^ •43;^ 45 45. 45 48 27;^ 33 43 49 54 S/2 4 5 6 6 7 5 6 7 8 9 10 12 11,600 15.350 31,500 24,500 31,700 39,500 48,000 19,800 25,350 33,100 39,300 48,200 Note— The cylinders mentioned in this table are adapted for 100 pounds steam pressure, non-condensing. For other conditions the cylinders-- will he varied to give best economy. 48 NOTES ON POWER PLANT DESIGN THE AJAX ENGINE, MADE BY HEWES & PHILLIPS NON RELEASING CORLISS VALVE GEAR FOR DIRECT CONNECTING UNITS tial Pressure n Pounds 125 1 '5° Size of Engine Revo- lutions Initial Pres! ure s 150 Diameter Pu ley Cubic Feet in Approximate Floor Space lielted From Center ot Engine to Center of Back From Center of Crank-shaft to end of From Center of Engine to Floor Con- stant in Pound .00 1 ,25 Dia- Based lOO on I Steam Exhaust meter Face Foundation Length Width Bearing Cylinder Pound M. E. P. kilowatts Inches Horse-power Inches Inches Inches Inches Ft. Ins. Ft. Ins. Ft. Ins. Ft. Ins. Ft. Ins. I Rev. 58 72 88 12 X 15 225 86 108 132 4'A 6 72 16 252 II 7 6 4 6 8 21 .0085 66 85 104 13 X 15 225 100 127 156 5 6 72 16 260 II 7 6 4 6 S 21 .0100 73 91 112 '3>^xi5 225 IIO '37 168 5 6 72 16 260 I I 7 6 4 6 I 3 21 .0108 79 95 120 14 XI5 225 118 147 181 5 6 72 16 270 I I 8 6 5 8 3 21 .0116 83 los 129 I4>^xi5 225 125 157 '93 5 6 72 16 270 1 I 8 6 5 ? 5 21 .0124 90 "3 140 '5 X15 225 135 170 210 6 7 72 16 280 I I 10 6 5 I ^ 5 21 .0134 100 1-9 160 16 X 15 225 150 193 237 6 7 72 16 280 11 10 6 5 ' S S 21 .0152 83 105 129 14 X 16 225 125 '57 '93 6 7 72 16 270 II 8 6 5 9 21 .0124 90 112 '38 H}4xi6 225 ■35 169 207 6 7 72 16 270 I I 8 6 5 0. 9 21 •o'33 96 120 150 15 X 16 225 145 181 223 6 7 72 16 290 I I 10 6 5 ' 9 2 21 .0143 106 136 .67 i6 X 16 225 160 204 251 6 7 72 18 290 II 10 6 9 5 2 9 2 21 .0161 123 '54 190 17 X 16 225 185 23' 286 6 7 73 iS 290 I I 10 6 9 1 - 9 4 21 0183 "3 '43 '73 16 X 18 210 170 215 265 6 7 78 20 300 ■3 5 7 7 6 9 6 21 .0182 130 162 200 17 X 18 210 '95 244 300 6 7 78 22 320 ■3 5 7 9 6 I 9 6 21 0206 '43 181 223 i8 X18 210 215 272 335 6 7 78 24 330 '3 5 7 1 1 6 3 9 8 2 I .0230 160 202 269 19 X18 210 240 3°4 404 7 8 78 26 360 '3 8 10 7 9 8 2 I .0257 178 225 276 20 X 18 210 268 338 415 7 8 78 28 420 '3 8 9 7 3 9 10 2 I .0285 130 162 200 17 X 19 200 ■95 245 301 6 7 84 24 430 13 1 1 7 II ^' ^ 10 2 I .0217 150 182 225 18 X 19 200 220 274 337 6 7 84 25 440 13 1 1 8 (> 3. 10 2 I .0243 160 204 251 19 X19 200 240 306 376 7 8 84 26 450 '3 1 1 8 10 7 10 2 2 I .0271 180 226 278 20 X 19 200 270 340 418 7 8 84 26 460 '3 II S 10 7 10 6 2 I .0301 '53 192 236 18 X 20 200 230 289 355 6 7 84 26 470 '4 10 8 2 6 5 10 8 2 I .0256 170 215 264 19 X 20 200 25s 322 396 6 7 84 28 480 '4 10 9 7- 3 10 S .0285 190 238 293 20 X 20 200 285 358 440 7 8 84 3° 500 14 10 9 2 7 4 10 10 .0317 206 262 323 21 X 20 200 310 394 485 7 8 84 32 500 14 10 9 2 7 4 1 1 2 I •0349 Horse-power. — In the computation of the power of an engine, the prime factors are area of cylinder, pressure of steam, piston speed, and point at which steam is cut off. Our calculations of horse-power, as indicated in the above table, are based upon an initial steam pressure of 100, 125 and 150 pounds per square inch, valve gear cutting off at ^ stroke, piston speed varying from 562 feet for the smallest up to 666 for the largest, size. These conditions can be changed, and by increasing one or all, the power of an engine is increased in like proportion. NOTES ON POWER PLANT DESIGN 49 HEWES & PHILLIPS HEAVY DUTY CROSS COMPOUND CORLISS ENGINE — TANGYE TYPE Dimensions of Cylinder I and Wliee s Horse-power 80 Lbs. Initial Pressure % Cut-oH Horse-power 90 Lbs. Initial Pressure % Cut-off Horse-power too Lbs. Initial Pressure K Cut-off Size of Quadrangle witliin which Engine ii-.cluding Fly-wheel will stand Length of Crank-shaft from Outside of Main I3earhig5 Distance from Center of Crankshaft to End of Cylinder Height from Base-plate Ho to Center of C Crankshaft B Pc se -power onstant ased on und M. P.. I Rev. Bore Stroke Diameter Face Weight Revs, per Horse- Revs, per Horse- Revs, per Horse- Length Width E. in Inches in inches in Feet in Inches in Pounds Minute power Minute power Minute power Ft. Ins. Ft. Ins. Ft. Ins. Ft. Ins. Ft. Ins. 10 24 6 12 4000 125 5° 125 55 125 62 ■ '3 I 5 " 5 2rV 10 I I II 0094 12 24 7 14 5000 125 75 125 84 125 93 14 1 1 6 9 5 3 10 II I II 0137 12 30 8 '4 6coo 120 85 120 94 120 104 16 II 6 9 5 2i3 12 II I II 017I 14 30 8 18 7000 120 '■5 120 125 120 '37 17 7 7 7 5 '0^ 13 ' 2 I 0230 U 36 9 18 Sooo ) 10 126 I 10 '43 I 10 160 '9 7 7 7 5 ^0% 15 I 2 I 0276 i6 30 10 20 9000 120 '5' 120 170 120 190 iS 5 8 8 6 6 13 5 2 3 0301 :6 36 10 24 1 0000 I 10 166 I 10 190 I 10 2'3 20 5 8 8 6 6 ■5 5 2 3 0361 i6 42 12 24 10600 100 177 100 200 100 S26 23 5 8 8 6 6 '7 5 2 3 0421 i8 36 12 26 12000 I 10 210 I 10 240 7 10 270 21 6. 9 5 8 3rV 15 6 2 5 0457 i8 42 14 28 14000 100 2^3 100 255 100 287 24 6 9 5 8 3tV 17 6 2 5 0533 20 36 12 28 I4OCO I 10 236 no 270 110 305 22 II 10 3 8 8'A 15 II 2 6 0564 20 42 '4 30 17000 100 275 100 3'5 100 355 24 II 10 3 8 S'A 17 II 2 6 0658 20 48 16 3j 19000 90 2S4 90 3^5 90 365 27 II '0 3 8 S'/, 19 1 1 2 6 °753 22 42 16 36 21000 100 334 100 382 100 422 26 2 1 1 I '0 3 18 2 2 9 0797 22 48 16 38 23000 90 344 90 393 90 442 28 2 II I 10 3 20 2 2 9 0911 22 54 16 40 25000 So 344 So 395 80 442 30 2 1 1 I '° 3 22 2 2 9 1024 24 42 .6 40 22000 100 398 100 454 100 510 28 8 12 " 3 20 8 2 I I 0948 24 48 16 40 24000 90 408 90 468 90 527 30 8 12 " 3 22 8 2 n 10S4 24 54 16 44 26000 80 410 80 468 80 526 32 8 12 " 3 24 8 2 It 1219 26 48 16 44 30000 90 4S0 90 548 90 6,7 21 5 2 9 1272 26 54 iS 46 32000 80 4S0 80 549 80 61S 23 5 2 9 1431 26 60 18 48 34000 75 501 75 572 75 644 25 5 2 9 1 591 28 48 18 48 32000 90 563 90 645 90 726 21 9 2 10 1477 28 54 iS 52 34000 80 563 So 645 So 727 23 9 2 10 1662 28 60 iS 54 36000 75 5S7 75 672 75 757 25 9 2 10 1846 3° 48 18 56 34000 90 646 90 739 90 833 22 2 2 10 1694 30 54 18 60 38000 80 6^6 80 740 80 834 Shafts as de sired 24 2 2 10 1906 30 60 18 64 4OOGO 75 671 75 771 75 86S 26 2 2 10 2118 32 48 18 58 36000 90 736 90 841 90 948 22 7 2 10 1928 32 54 20 62 39000 So 734 So 841 80 947 24 7 2 10 2166 32 60 20 66 43000 75 766 75 877 75 9S8 26 7 2 10 2410 34 54 20 78 60000 So 840 80 961 So 1083 24 1 1 2 I I 2477 34 60 20 78 60000 75 865 75 99° 75 1115 26 II 2 II 2720 Horse-power. — In the computation of the power of an engine, the prime factors are area of cylinder, pressure of steam, piston speed, and point at which steam- is cut off. Our calculations of horse-power, as indicated in the above table, are based upon an initial steam pressure of 80, go and 100 pounds per square inch', valve gear cutting off at ^ stroke, piston speed varying from 500 feet for the smallest uj) to 750 for the largest size. These conditions can be changed, and by increasing one or all, the power of an engine is increased in like proportion. 50 NOTES ON POWER PLANT DESIGN CONDENSERS AND ACCESSORIES The pressure in a condenser is always higher than the pressure due to the temperature of the steam. The difference between the pressure in the condenser and the pressure due to the tem- perature of the steam, gives the pressure exerted by the air in the condenser. The air comes in part from the feed water entering the boiler, in part from the circulating water, in the case of the jet condensers, and in part from leakages of air into the condensing outfit. Water at atmo- spheric conditions, contains from 2 to 5 per cent of air by volume. It is evident that the leakage of air into the condensers may be much or little according to the care with which the condenser outfit was installed. In general, a wet air pump handling the air and circulating water for a jet condenser, when running at a piston speed of 50 feet per minute, should displace in one hour from three to three and one-half times the volume of circulating water used per hour. The wet pump for a surface condenser handling both condensed steam and air, should displace per hour, 35 times the volume of water coming out of the condenser per hour as condensate. The displacement of 35 volumes is generally considered about right for a vacuum of 28 inches. If higher vacuua are carried, the figure should be increased, running up to perhaps 40. The vacuum in a condenser is generally measured either by the difference in level of mercury in a U-tube, or by the height of a column of mercury in a single tube, this height being measured above the surface in an open vessel filled with mercury, into which the tube extends. The differ- ence in level thus read, should be corrected for temperature, if the percentage of the perfect vacuum is to be obtained by comparison with a barometric reading reduced to 32 degrees and to sea level. This correction may be made with sufficient accuracy as follows: — The corrected height = observed height (1 - .0001 (t - 32) ). The amount of cooling water required for the condensation of a pound of steam is commonly figured, assuming a 20 degree increase in temperature with cold cooling water at 70 degrees. The heat to be abstracted from each pound of steam which has passed from the throttle through the condenser may be found by subtracting from the heat brought in by a pound of boiler steam, the heat transformed into work by a pound of this steam and the heat of the liquid condensate leaving the condenser. If steam is bled from or supplied to any stages or receivers of a turbine or engine, the amount of heat to be abstracted by the condenser may be calculated by the same process. Proper allow- ance of course must be made for the steam which is taken out before reaching the condenser and for the heat in any steam put back into the condenser and for the heat, from such steam, which is transformed into work. See in this connection the discussion of the bleeder type turbine under the general heading of Cylinder Efficiency and Rankine EflBciency. SURFACE CONDENSERS (1) The rate of heat transmission through a tube is nearly directly proportional to the mean difference in temperature between the liquid on the inside and the vapor on the outside of the tube. (2) The rate of heat transmission is proportional to the square root of the velocity of the vapor normal to the line of tubes. (3) The rate of heat transmission is proportional to the cube root of the velocity of the water in the tubes. An article by Mr. Orrok in "Power" of August 11, 1908, gives a summary of the various tests made on the transmission of heat through condenser tubes, A smooth curve representing the mean of the various experimental results was drawn by Mr. Orrok, who proposed the following formula NOTES ON POWER PLANT DESIGN 51 for U the heat transmission per sq. tt. per hour per degree difference of temperature inside and outside of the tube: — _ 3 f/ = 17 Ws V.023 + Vy, Vs = velocity of steam by the tube generally taken as 625 ft. p. sec. Vw = velocity of water in tube in ft. per sec. Values read from the curve give — 3l. of water in tubes in ft. per second. U .5 1 2 3 350 430 545 620 Vel. of water in tubes in ft. per second. U 4 675 5 725 6 775 7 815 Experiments by Mr. E. Josse have shown much higher values for tubes which were drained in such a way that the steam condensed on the upper rows did not trickle down over the lower rows but was drained to the shell, thus keeping the efficiency of the lower tubes equal to that of the upper tubes. For such tubes it appeared that the constant 17 in the preceding formula for U should be made 20 or 25. Later on Mr. Crrok did a considerable amount of experimental work on this subject and as a result of his more recent work he developed the following formula and conclusions which are copied from Transactions A. S. M. E., 1910. (a) The heat transferred from condensing steam surrounding a metallic tube to cold water flowing through the tube is proportional to the seven-eighths power of the mean temperature dif- ference of the water and steam temperatures. This is equivalent to the statement that the co- efficient of heat transfer, U, is inversely proportional to the eighth root of the mean temperature difference. (b) The coefficient of heat transmission, U, is approximately proportional to the square root of the velocity of the cooling water. (c) The coefficient U is independent of the vacuum and of the velocity of the steam among the tubes or in the condenser passages. It may be proportional to the square root of the velocity normal to the tubes, but in all common cases this velocity does not vary more than a tenth part. (d) The effect of air on the heat transferred is very marked indeed, particularly at high vacuua, and most of this air is due to leakage through the walls and joints of the apparatus. The effect of the presence of air in reducing the value of U is as follows: where Ps is the partial pressure due to the steam and Pt is the total steam and air pressure. (e) Taking the heat transfer of the copper tube as 1.00 under similar conditions the transfer for other materials is approximately as follows: — copper, 1.00, Admirality 0.93, aluminum lined 0.97, Admiralty oxidized (black) 0.92, aluminum-bronze 0.87, cupro-nickel 0.80, tin 0.79, Admiralty lead-lined 0.79, zinc 0.75, Monel metal 0.74, Shelby steel 0.63, old Admiralty (badly corroded) 0.55, Admiralty vulcanized inside 0.47, glass 0.25, Admiralty vulcanized both sides 0.17. This coefficient (due to the material of the tube) will be designated by n. Corrosion, oxidation, vul- canizing, pitting, etc., have also a marked effect in reducing the transfer. This reduction, best shown by the Admiralty tube which gave fx = 0.55, may reduce the transfer at least 60 per cent. (f) The foregoing conclusions may be expressed mathematically as follows: 05 52 NOTES ON POWER PLANT DESIGN where C = the cleanliness coefficient varying from 1.00 to 0.5 fj, = material coefficient varying from 1.00 to 0.17 (f = the steam richness ratio „ ^ varying from 1.00 to Vv, = the water velocity in ft. per sec. 9 = the mean temperature difference. K = a constant, probably about 630. The effect of the length of tube, or rather length of water travel, has not been considered and the design of the condenser must be such that there is a free steam passage to every tube. (g) This expression for U is cumbersome to use and for modern turbine condenser work cer- tain conditions may be taken as well settled. The guaranteed vacuum i,, usually 28 ins. The entrance circulating water is usually 70 deg. and a 20-deg. temperature rise is considered economical. Under these conditions 6 =18.3 and 6'^ = 1.44. 6 calculated on the geometrical curve is 18.2. For these cases it will be nearly as accurate and much simpler to calculate 6 by the logarithmic no r\ method, neglecting 6 in the denominator and using 435 or :j— 77- for K^. The expression will then be U = K'C n 3g 3k' /2f llf llf L ^4' 2'-9§" B'-yf 3'-3i" 2''9f Cirv. Inlet dia 7' 12' 14' /(>' 18" M 6" /o" /o' /4" I4-' P '^'-li' ^■-7f 4-'-il" 4'-llf S'-3k" N 8' -3" I'-o" II -2" 8' -10" lo'-o" 9 le" 18' a'-a' 2'-e>" 2'- 4' O a'- 6" J '-4-" 3-9" 4-'-8" 4- '-10" C/'rc. Disch. dia. 7" 12" 14' 16' 18" P /a' 23" 2'- 4-" -? '- 7 " 2'- 10" r /a" IS' 18" 19" 21" Q I2£ ,2k' llf /^i' I9M Turb. 3t d/a 2s 2k" 2k' 2k' 2k' /? 18' 18' 4'-er' ^'-",7" 4'-ll,f t izi" 12k' '2s lof 'Of s 2'-l" 2-7" 2'-7f 2'-ll^" 2'-iir u isf isf isf 19" /9' ■St. /e/ef c^/a 2Z' 36' 4-2" 4-a' 4-8" \r ■ ^£ ■^k' 4k' 37Z 3^" a 6-uf 7-/5-" 9 '-of a'-iof 8- llf Turb- S'X- d/a. 4' 4' 4-" 6' 6' b 2j£ /-7i' 2-8" 3-0" 3-3" »^ iH' 17k' 17k' '7rl' ''16 y n" 11' 11" Ilk" Ilk" Note:- In the 1000 ana/ 2000 j^. ft, s/zss no rectucing gear is ussid, the turbine couples direct to pump ^. ^ Where no reducing gear is used these connections are on other side of cona/enser from thaf st)o^vn in c/iogrom. (j> In th^o smallest -sizes priming connect/on opens alon/ntyard. NOTES ON POWER PLANT DESIGN THE WHEELER CONDENSER AND ENGINEERING COMPANY WHEELER ADMIRALTY SURFACE CONDENSER Sq. Ft. Diameter of of Weight Surface A B C D E F Tube Lbs. 463 7'-0" 8'-3" 3'-0" 15J<" 21 J<" 18H" Vs" 3400 606 8'-0" 9'-4" 3'-l" 16X" 22><" 22H" Vs" 4500 751 8'-0" 9'-7" 3'-0" IQVs" 22><" 2'-l" Vs" 5200 1042 8'-0" 9'-8" 3'-5" 18K" 2'-2j^" 2'-3K" Vs" 6600 1109 8'-0" 9'-5" 3'-8" IQVs" 2'-2K8" 2'-4><" y." 7200 1379 8'-0" lO'-O' ■ 4'-0" 221/8" 2'-5^" 2'-9^" y," 9200 1778 8'-0" 10'-2" 4'-4" 23'A" 2'-8X" 3-2" y" 11100 2051 8'-0" 10'-2" 4'-8" 2'-l" 2'-ll>^" 3'-4" y" 12900 2223 lO'-O" 12'-5" 4'-6" 2'-l" ■ 2'-8>^" 3'-2" y" 14000 2757 8'-0" 10'-8" 5'-4" 2'-3X" 2'-93^" 3'-10" y" 16200 3446 lO'-O" 12'-7" 5'-4" 2'-5>^" 3'-lK" 3'-10" y" 19600 4135 12'-0" 14'-7" 5'-4" 2'-5>^" 3'-l>^" 3'-10" y" 23000 4679 12'-0" 15'-0" 5'-6" 2-6" 3'-4>^" 4'.y," y" 26500 5069 13'-0" 16'-0" 5'-6" 2'-6" 3'-4>^" 4'->^" y" 28300 5849 • 15'-0" 18'-0" 5'-6" 2'-6" 3'-4>^" i'.y," y" 31800 6733 15'-0" 17' 0" 5'-8" 2'-7" 3'-7>^" 4'-6" y" 36900 7714 13'-0" 16'-0" 6'-6" 3'-0" 4'-2>^" 5'-2K" y" 44200 8307 14'-0" 17'-0" 6'-6" 3'-0" 4'-2K" 5'-2K" y" 46700 60 NOTES ON POWER PLANT DESIGN WESTINGHOUSE LE BLANC JET CONDENSERS SIZES Dia. Dpenings 8zb 1 2 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 1 3"-4y2 6"-6 3/4 30 333/8 261/2 163/4 151/8 10 91/7 25 V: 22 34 35 Vs 2, 6"-ll/4 13% 22 5 3 6 5 2 3 "-4 1/2 6 "-6 3/4 31 y 333/s 261/2 163/4 151/8 10 91/, 25% 223/g 35 ys 2 6"-li/4 13% 22 5 3 6 5 4 3"-10V2 7"-iy8 33 34 273/4 18 151/, 10 91/, 253/ 23% 3 "-2% 28% 6"-6y8 141/4 28 6 3% 7 5 5 3"-10y2 7"-l% 351/6 34 273/4 18 151/, 10 91/, 253/4 23 Vr 3 "-2% 28% 6"-6y8 141/4 28 6 4 7 5 7 4"-4V2 8"-5i/2 3 "-3 35 H 271/8 20 173/, 10 10 y, 301/4 25 3"-5% 313/, 7"-10 151/4 30 7 4 Cl 6 8 4 "-4 1/2 8"-5i/2 3"-7 35 H 271/8 20 173/4 10 10 1/, 301/4 25 3"-5y 313/t 7"-10 151/4 30 7 S V 10 5"-0 8 "-8 1/4 3"-10i/2 35i| 271/8 20 18% 10 10 v, 301/4 251/4 3"-9% 35 7"-103/4 151/4 36 9 6 12 G U 5"-0 8"-8i/4 4"-0i/2 35 M 271/8 20 181/8 10 10% 301/4 251/4 3"-9% 35 7"-103/, 15% 36 9 6 n 6 13 5"-7i/2 9"-10y8 4 "-8 3"-7y8 34 y8 21 19 10 113/ 353/4 28% 4"-13/f 3"-3 8"-ll% 20% 42 12 6 14 U 5 "-7 1/2 9"-ioy8 5"-0 3"-7y8 34 ys 21 19 10 113/1 353/4 28% 4"-13/8 3 "-3 8"-l 1 % 20% 42 12 7 14 6 16 0"-7i/2 10"-113/8 5 "-6 34 3"-10H 3"-lA 24 193/4 9% 14 3"-7 29 y. 4 "-8 1/2 3"-7i/, 9"-113/8 22% 48 14 8 If 10 17 6"-7i/2 10"-113/8 6"-0 3"-10|i, 3"-lA 24 193/4 9% 14 3 "-7 29% 4"-8i/2 3"-7% 9"-113/8 22% 48 14 9 10 10 18 7 "-5 1/2 13"-5i/2 6 "-4 1/2 4"-6H 3"-8A 3"-10i/4 18% 9% 14 4"-3l/4 291/2 5"-li/2 4"-2 12"-2i/2 293/4 54 18 9 20 10 19 7"-5i/2 13"-5i/2 6"-8i/2 4"-6H 3"-8A 3"-10i/4 18% 9% 14 - 4"-3i/4 291/2 5"-li/2 4"-2 12"-2y2 293/, 54 18 9 20 10 NOTES ON POWER PLANT DESIGN Gl WESTINGHOUSE LEBLANC JET CONDENSERS CAPACITIES Turbine Driven Based on 5° Terminal Difference. Con- Circulating » 28" VACUUM denser Wpt-r Number Lbs.per Hr. 35° F. 40° r. 45° F, 50° F. 50° F. ■55° F. 60° F. 70° F. 75° F. 80° F. 1 235,000 17200 15750 14400 ISCOO 11575 10150 8750 7300 5950 4500 2 320,000 20SC0 19200 174C0 15700 14000 12250 10500 8800 7200 5450 4 350,000 22750 20750 19000 17100 15880 13400 11600 9550 7800 5950 5 400,000 26000 23800 21700 19600 17500 1.5325 13200 11050 9025 6820 7 000,000 39000 £5750 32750 290C0 26400 23000 19750 16600 13400 10250 8 750, ceo 49000 44750 40750 37000 32750 2rooo 24800 20500 16750 12850 10 825,000 53500 49000 44750 40400 34750 31800 27300 22750 18400 14100 11 940.000 610C0 55800 51000 46000 41000 36000 31000 25750 21000 16000 13 1,200, OCO 775C0 71000 C5200 58600 52750 46000 39250 33250 26600 20500 14 l,5.50,0CO 100600 92500 84000 75750 57750 59300 51150 42750 34650 26400 16 l,850,CfO 120500 11000 100500 910C0 81000 71000 61000 51000 41500 31600 17 2,200 OCO 143000 I310C0 119000 107500 96000 84000 72500 60800 49250 37500 18 2,620,000 170000 356000 142000 128000 114500 100320 86300 72250 58600 44500 19 3,000,000 194700 178500 163000 147000 131000 1150C0 99040 82000 67000 61100 20 4,000,000 26C00O 238000 217500 196000 174600 1.53200 132000 110300 89400 68100 21 5,000,000 325CC0 298000 271500 245000 218500 191500 165300 138000 111600 85200 22 6,000,000 2S90CO S57C0O ?25000 293000 262000 2300C0 198000 166000 134000 102000 23 7,000 000 4550C0 416000 £80000 3420GO 305000 268000 231000 194000 156000 119000 24 9,000,000 5800C0 530C00 485000 447000 390000 344000 295000 248000 212000 153000 25 11,000,000 710000 65C0C0 590000 545000 475000 420000 360000 3O4000 258000 187000 26 13,000,000 8400CO 77C0C0 700000 645000 560000 495000 425000 360000 305000 220000 The figures given aro based on the assumption that the temperature of the mixture of water and steam is 5 degrees less than the theoretical temperature corresponding to the vacuum. The following conditions are assumed: 1. That condenser pumps are steam driven. 2. Temperature of injection water . 70 Degress F. 3. Level of watar supply bslow top of condenser dDss not exceed 13 Feet 4. Discharge water is to be elevated above base of condenser, not to exceed (including pipe friction) 4 Feet 5. Suction pipe is to be so arranged that friction head will not exceed the equivalent of. 2 Feet 6. Vacuum at rated load, referred to a barometric pressure at 30 inches ... 28 Inches C2 NOTES ON POWER PLANT DESIGN THE WHEELER CONDENSER AND ENGINEERING COMPANY DIMENSIONS OF WHEELER-EDWARDS AIR PUMP Capacity in lbs. per hour Size 28" Vac. Suction Discharge A B C D E 3Kx8x6 ' 22£0 3" 3" 5'-2'^" 2'-3" 8%" 16?^" 22" 4x10x8 4500 4" 4" 6'-7" 2'-6" 10^" 20>^" 2'-6" 5x12x10 7500 5" 5" 7'-9" 3'-0" 13" 243X" 3'-0" 6-14-10 107£0 6" 6" 8'-2" 3'-6" 15" 2'-2K" 3'-3" 7-16-10 14000 6" 6" 8'-8" 4'-0" ^ I^Va" 2'-2" 3'-6" 8-18-12 20750 7" 7" 9'-6" 4'-6" 18" 2'-8" 3'-9" 8-20-12 26000- 8" 8" 9'-8" 4'-6" , 18K" 2'-8" 3'-9" 9-24-12 36750 10" 10" 9'-10" 5'-0" 21K" 2'-my2" 4'-4" 10-26-12 43250 12" 10" 10'-8" 5'-0" 23H" 3'-0" 4'-4" 12-30-14 62500 NOTES ON POWER PLANT DESIGN 63 THE WHEELER CONDENSER AND ENGINEERING COMPANY DIMENSIONS OF WHEELER ROTATIVE DRY VACUUM PUMP H A H H E- I Capacities for Condenser Surface in lbs. per Size Size Size hr. 28 ' Vac. Suction Discharge A B C qD E 5-12-12 18000 4" 2" 9'-ll>^" 3'-l" 3'-3" 17}4" 2'-l" 7-14-14 27400 4>^" 3" 11' 3%" 3'-6" 3'-6" 20" 3'-4" 7-16-10 34600 5" 3" 11 -3 J^" 3'-8" 3'-6" 22" 3'-4" 9-18-16 48000 6" 4" 13-4" 4'-3" 4'-6" 24" 4'-l" 9-22-16 68600 8" iH" 13'-5>^" 4'-7" 4'-6" 2'Aj4" 4'-l" 10-26-18 102600 9" 5" 15'-53^" 5'-J<" 5'-6" 2'-S}4" 5'-0" 12-30-18 130000 10" 6" 15'-7" 6-3^" 5'-6" 3'-4" 5'-0" 14-34-18 154600 14' 6" 15'-6" 6'-4" 5'-6" 3'-5" 5'-3y<' 16-30-24 160000 10" 6" ' 19'-9" 6'-7K" 7'-0" 3'-K" 5'-9" 16-36-24 197000 16" 8" 20'-7K^" 6'-5" 7'-0" 2'-9>^" 5'-9" Note: — For 26" Vacuum capacity may be doubled. For 27" Vacuum capacity is 50% greater. For 283^" Vacuum capacity is 25% less. LONGITUDINAL SECTION OF AIR CYLINDER •=howing Rotative Valve and Flash Port for minimizing clearance less. WHEELER PATENT COMPOUND DISCHARGE VALVE The lift if regulated by outside adjusting screws; if water collects in the cylinder the secondary spring compresses and gives extra large lift. 64 NOTES ON POWER PLANT DESIGN THE WHEELER CONDENSER AND ENGINEERING COMPANY WHEELER DUPLEX HOT WELL PUMP Capacity lbs. per Size hour Suction Discharge A B C D E 3x2^x3 4200 2" \y^" 2VA" 2'-iy,-' 121^" wy 5X" 4j^x4x4 11500 2K" IW 3'-63/8" 3'-63/," 17H" 14" 8^8" 5Xx4>^x6 57000 6" 5" 4'-10" 4'-10" 2'-6K" 2'-l>^" 15" 6x8>^x6 73500 6" 5" 4'-10" 4'-10" 2'-6X" 2'-ly2" 15" 7>^x8KxlO 98000 10x10x10 142000 8" 7" &.y," 6'-J<" 3'-4>i" 3'-6>^" 7K" 10x12x10 195600 10" 8" 6'-lK" 6'-lK" 2'-9>^" 3'-ll" 8><" NOTES ON POWER PLANT DESIGN 65 THE WHEELER CONDENSER AND ENGINEERING COMPANY WHEELER CENTRIFUGAL PUMP ^iScAoiTfe Gallons per Size Minute A B C D E F 4" 400-475 18^" 12K" 15^" 9J<" 17^" 21K" 5" 600-725 22" 12>^" 20J<" IVA" 19^" 23^" 6" 900-1050 23" 15" 22>^" 12" 2VA" 2'-l" 8" 1600-1900 2'-3^" 16" 2l%" 14K" 2'-2" 2'-53^" 10" 2500-3000 2'-7" 18" 24^" 16" 2'-6X" 2'.\VA'- 12" 3500-4200 Z'-y^" 22" 2'-4>^" . 18K" 2'-9" 3'A" 14" 4800-5600 3'-6" 22" 2'-6K" 21J<" 2'-6><" 2'-llJ<" 16" 6400-7500 3'-9" 23>^" 2'-8K" 233-^" 2'-9><" 3'-2>^" 18" 8000-9500 4'-l^" 2'-l" 3'-2" 2'-0" 3'-2?<" 3'-ll>^" 20" 10000-11600 4'-l" 2'-3" 2'-ll" 22>^" 3'-4>^" 4'-K" SA" 14000-17000 4'-10K" 2'-8" 4'-0" 2'-4" 4'-0" 4'-8" 30" 22000-26000 5'-4" 3'-3" 3'-10" 3'-2" 5'-K" 5'-7" 66 NOTES ON POWER PLANT DESIGN C. H. WHEELER SPECIAL EXHAUST GATE VALVE Size of DIMENSIONS Valve A. B C D E F G H J K L M 16 8 14 16 42 48 10 23>^ IVs 13>^ IVs 16 20 10 14 20 54 53 11^ 271^ VA 16 IVs 20 24 10 16K 24 55 59 13 32 1^ 16 m 20 30 14 18 30 65 69 UVs 38^ IK 21 w% 24 36 18 20 33 77 83 16 46-^ IH 25 1V-, 36 42 20 22 42 89 95 16 53X 2 27K V/2 36 C. H. WHEELER T" t1 M ^ C. H. ^ WHEELER C Surface Condenser with Multiflex Automatic Relief Valve, Gate Valve and Expansion Joint. NOTES ON POWER PLANT DESIGN 67 THE C. H. WHEELER "MULTIFLEX" PATENT EXHAUST RELIEF VALVE This valve consists of a brass valve deck which is indived into a number of rectangular port'^ arranged in rows, each port accurately faced on an angle and covered by a flap valve made of Phos- phor Bronze sheet, coiled at one end. The valves in each row are mounted on, and controlled by, a slotted bronze stem, to one end of which is keyed a bronze crank; these cranks have a common connecting rod which communicates with an external lever and locking device which not only allows the valves to be secured in either an open or closed position, but the valves can be seated with any desired degree of tension, because of the coiled spring. The angle of the ports and valve seats avoids abrupt turns and gives the steam an easy, smooth and noiseless passage through the valve. In normal operation the vacuum, or unbalanced condition of the atmosphere, holds the valve,* tightly on their seats; but to insure absolute tightness for high vacuum service, a water seal with brass globe valve on inlet side and visible funnel overflow with drain connection on discharge is provided. Size of Valve A B 6 28K 8 28K 10 29 12 29 14 37 16 42 18 37 20 45 24 56 30 64 DIMENSIONS C D 9^ 11 ^'A 13>^ 13^ 16 15J^ 19 12 21 13 23>^ 21 25 19 K 27K 26 J^ 32 26 38M E Shipping Weight IVh 330 lbs li/s 384 " m 900 " Wa 975 " m 1128 " IH 1440 " VA 1995 " VA 2440 " \A 3822 " \y. 6000 " 68 NOTES ON POWER PLANT DESIGN KNOWLES VERTICAL AUTOMATIC EXHAUST RELIEF VALVE With screw lifting device s D L H A B HH 1, « i Number ^ Si7,e V C B = .2 fc Q 2 Width Height Height above Gentle Distance below Centre Height Over All S 5 S 5 E 2 S « and Size of Bolts 4 9 12 9 lOlf cl 1 54 16A 1 74 4-1 5 10 134 lU 13 64 64 m * «4 8-f 6 11 15 12;^ 14|t 7S 7tV 21H i 94 8-f 8 13^ 18 17 17^ 9J 84 25 111 8-f 10 16 24 23 231 111 lis 31S 14 14J 12—1 12 19 26 25 27S 144 12i m 1* 17 12—1 14 21 32 29 318 16S 15 43 n 181 12-S 16 23^ 36 32 34f 18 161 m 14 2U 16-i 18 25 42 36^ 38g 19ft 181 544 14 221 16—1 20 274 48 411 m 214 21i 584 If 25 20—1 22 294 48 42i m 21s 22 61i 27i 20—1 24 3U 52 43i 464 241; 22i 641 If 29J 20—1 26 m 58 50 52 26 26 724 2 31i 24—1 28 36 66 56 59g 29S 291 m 2 334 28—1 30 38 72 604 634 314 32 871 2 354 28—14 Double dash pot with screw lihin§ device s D A L H E Thick- DIam. Number Diam. Heiglit Distance ness of of Bolt and Size Size of Flanges Face to Face Length WiJIh Height Centre to Inlet Flanges Circle of Bolts 4 9 94 144 9 144 41 1 74 4-1 5 10 11 14| lOi 161 54 * 84 8-fe 6 11 13 165 Hi 19 64 s 94 8^ 8 134 18 21| 16 25 9 113 8-g 10 16 19 24g 18 28t 94 14 14i 12-f 12 19 20 284 20 291 10 14 17 12-f 14 21 23 32| 234 34 114 u 181 12-S 16 234 27 36i 274 42 134 14 m 16-J 18 25 30 40J: 31 44g 15 14 221 16-1 20 274 34 444 34| 51 17 11 25 20-1 22 294 36 49i: 36i 56 18 1* 27J 20-1 24 314 37 49g 38J 58 184 n 29i 20-1 26 331 42 55 42 63 21 2 3U 24-1 28 36 46 59 46 67 23 2 334 28-1 30 38 50 63 50 72 25 2 354 28-14 NOTES ON POWER PLANT DESIGN 69 FLOW OF STEAM IN PIPES The area of a steam pipe, if the pipe is of short length, may be calculated by dividing the volume of steam to be delivered per minute by an assumed velocity of flow. For engines of the Corliss type taking steam in large quantities intermittently, a velocity not exceeding 6000 feet per minute may be used. A receiver having a volume equal to three times the capacity of the high pressure cylinder is sometimes placed close to the throttle valves of such engines. This re- ceiver furnishes a reservoir from which the engine draws steam; it enables a smaller steam pipe to be used and thereby -prevents the vibrations of the steam main which are so common in plants where slow speed engines are in use. For steam turbines or high speed engines which practically make a steady flow a velocity as high as 10,000 feet per minute may be used. The drop in pressure in a pipe of long length may be calculated by the formulae proposed by Mr. G. H. Babcock. These formulae are based on actual tests made on pipes up to 4" in diameter, and it is probable that the results will hold good for pipes of even larger size. Similar tests were conducted by R. C. Carpenter and a formula derived which is practically the same as that proposed by Babcock. In the formula : w = weight of steam in lbs. per minute. d = diameter of pipe in inches. L = length of pipe in feet. P = drop in pressure in lbs. per sq. inch. y = mean density in lbs. per cu. ft. V = velocity in feet per minute. V = 19,590 -^ Pd yL 1 + 3.6) d W=87 u-^ L ( 1 +• ■ P=. 0001321 \-}r VELOCITY OF EXHAUST STEAM The velocity of exhaust steam is taken from 6000 feet per minute for steam at 3 pounds back pressure to 40,000 feet per minute at a 29.5" vacuum. As the pressure gets lower the velocity increases, and some engineers use velocities which would increase from 20,000 feet per minute at a 26" vacuum to 35,000 feet per minute for a 29" vacuum. There has been in the past but little information as to the drop in pressure or the loss of vacuum due to these high velocities. Two series of experiments were carried on in the engineering laboratories at M.I.T. to determine the loss of pressure with such velocities. These experiments were with a pipe 6" in diameter. While the results apply specifically to a pipe of about this size it is probable that the equations may be used for pipes of larger sizes. No doubt the drop in pressure in the larger size pipe will be less than given by the equation. These experiments cover a range from a 25" vacuum through 70 NOTES ON POWER PLANT DESIGN 29H"- The formulae proposed are modifications of the Babcock formula and the letters used have the same tneaning, i. e.: L = the length of pipe in feet. y = the mean density of the steam in lbs. per cu. ft. V = mean velocity of the steam in ft. per min. P = difference in pressure in lbs. per sq. inch. d = diameter of the pipe in inches. Pd V = 13,700 xl o~ft"\ for straight pipe. „.L(l+ljl) P = .0001791 Tr ^ for straight pipe. y d^ Pd V = 9600 \ o-g \ for a 90° elbow. Pd V = 7200 \ 3~6~\ ^^^ ^^^ ^^° elbows making a return bend. yLii+-j-) The accuracy of the work does not warrant calculation of results within velocities of 500 feet either side of the true velocity. Problem to Illustrate Application of Formula. Suppose that the exhaust pipe leading from a turbine to a condenser is 15' long, 20" diameter, with an elbow at each end. If it be assumed that the steam has a mean velocity of 30,000 feet per minute, what will be the drop in pressure between the turbine and the condenser? The vacuum midway between the turbine and the con- denser being 28^", barometer 29.95". The absolute pressure is .933 lbs. and the specific volume of steam at this pressure is 355 cu. ft. P X 20 For the straight pipe 30,000 = 13,700\ -^ ■ - ^5-5X1^(1 + P = .012 lbs. / Px20 For each elbow 30,000 = 9600 \-j — o X2(l+- 3.6 \ 20 / 355 ' ' 20 P = .003 Note: — The length of the elbow is taken as 2 ft. along the center line. The total loss is .012 + .003 + .003 = .018 lbs. •018 n.// f = .04 of mercury pressure. .491 The loss resulting from an elbow is equivalent to the loss in a piece of straight pipe having a length a little greater than twice the distance along the center line of the elbow. NOTES ON POWER PLANT DESIGN 71 Example to Illustrate An engine is connected to a barometric tube condenser through 40 feet of vertical pipe, 10 feet of horizontal pipe and three elbows; one elbow being located at the exhaust opening of the cylinder and the second and third elbows being on the vertical pipe leading to the condenser. The exhaust pipe is 12" diameter and the vacuum to be maintained is 26", with the bt rometer at 30.1". If the maximum difference in pressure between the condenser and the engine is to be not over .1" of Hg. how many pounds of steam per hour can be put through this 12" pipe? The length through the center of a 12" elbow is about 1 foot so that about 1x2x3=6 feet should be added to the length of the pipe making a total of 56 feet. .0491 X 12 V = 13,700 \~i g-^rv r = 16,150 ft. per min. ^^^^i+T2-; 172 16150 X .7854 x 60 172 Had .2" mercury been the greatest drop allowed = 7370 lbs. 1.2 X .491 X 12 X 172 V = 13,700 \ g-g^ V = 22,850 56(1+ ^2 and 10,400 lbs. could be taken care of through the 12" pipe. 72 NOTES ON POWER PLANT DESIGN FEED WATER HEATERS Feed water heaters are of two classes, open heaters and closed heaters. In an open heater the water can not be heated above 212° while in a closed heater higher temperatures than 212° are possible. A primary heater is a heater placed on the exhaust pipe between the main engine or turbine and the condenser. A secondary heater which may be either an open or a closed heater utilizes the heat of the auxiliaries, exhausting at atmospheric pressure, in raising the temperature of the water leaving the primary heater to a temperature within 8 or 10 degrees of that of the exhaust steam. From the secondary heater the water passes through the economizer (if one is used) to the boiler. A feed water heater is very much like a surface condenser and consequently the same laws, regarding the interchange of heat per square foot of surface per degree difference of temperature, apply. The interchange of heat in condensers was found to be proportional to the square root of the velocity of the water through the tubes. Feed water heaters designed for torpedo boats, etc., where space is very limited have been made with the water flowing at high velocity in the annular space between two tubes placed one inside the other. The high velocity of water gives a large interchange of heat but requires 8 or 10 lbs. additional pressure on the pump forcing the water through the heater. The C. H. Wheeler Co. use the following formula in figuring the surface needed in a closed heater: S = sq. ft. surface W = lbs. of water per hour ts = temperature of steam °F. tc = temperature of cold water entering °F. th = temperature of hot water leaving °F. K = constant of transmission taken as 250 >S ^ 2.3026 logio ^^ ~ ^" K ^^" ts-tk It is always safer to put in a larger heater than appears at first to be necessary. Tables of dimensions of both a Primary and a Secondary heater are given. These tables will give the general dimensions only. The feed piping at a heater should be arranged so that in case of any trouble with the heater, the water can be by-passed around the heater. This necessitates three valves. The piping must be of brass in order to resist the action of the hot water. NOTES ON POWER PLANT DESIGN 73 VIS 1 "-1 SHELL. TUBES. N PIPING ' Capacity in gallons at one filling. ■5 % 2 i 5 5 J3 2 B s a J2 2 .2 "5 . ,, Heating Surface in sq. ft. it ■i 30 I_2 20 "K 15 21 25 II.6 4 6.0 33 40 12 24 ■M ■5 25 31 .14.3 4 9,8 39 50 • 14 28 i>. 17 29 41 18.7 5 ■63 45 6o 14 31 I'A 17 32 45 20.7 5 18,0 48 75 14 38 I'A 17 39 55 253 5 21.9 55 loo 16 40 2 i5 41 54 329 'K ■6 28.0 58 •50 16 S6 2 i5 57 76 46.0 IK 6 393 74 20O 20 44 2 28 45 105 6J.4 8 45-6 67 250 20 54 2 28 55 126 76.2 8 57 7 77 300 25 45 2 40 46 152 92 2'A 10 I, '2 768 72 350 25 53 2 40 54 180 1088 2!^ 10 ' iK 895 80 400 «o 48 2 50 49 204 1233 2>i 10 121. 8 78 500 30 S8 2 50 59 24s 147.0 12 147-8 88 600 30 61 2 55 62 282 171. 7 1 2 151.8 9' 700 34 58 2 68 59 333 201 5 1 2 2 'r, 1868 94 800 34 68 2 68 69 391 2364 12 ^'A 219,1 104 900 34 75 2 68 76 420 254 '5 VA 241.8 HI 1000 34 82 2 68 83 469 282.9 '5 2'A 264.2 118 s. ^ 300 435 625 700 750 87s idbo 1300 1650 1650 2450 3470 3800 4000 4:50 50CO 5JOO 5700 In computing the heating surface of the above table 15 per cent, is added for the corrugations. 74 NOTES ON POWER PLANT DESIGN Secondary Heater. o ID 25 f 1 .0 £j i S z "0 ^ c 5 « '5 •" Total Hcatiup Surface, Allowing 15 per cent. Tor Corruantioii'i' SIZES IN INCHES. F. c. H. K. L. M. N. p. R. s. T. 10 9 26 ■)< ,8.89 I 5 I ■ 4?i 49 8 .7?^ 36 'i 'i'4 42!..; 's'4 10 50 12 12 37 ''A 16.69 I )-> 6 154 16% 63 8 '9'. 48M 14 55 '4 n'4 II 60 12 12 45 '/2 20.30 ''A 6 >K 16% 71 8 '9 '-J Sf-'A 14 63>4 ■7'i "/ 80 12 12 60 iH 27.06 'A 6 '.M 16I4 86 8 '9'.- T'i 14 78 '4 ■7 ''4 ■' 100 12 12 74 iJi 33.38 ''A 6 1^4 16% 100 8 '9'j 85)4 14 92>:i '7 '4 -' '50 '5 24 60 iK 54.05 2 8 IM 20 92 9 23?^ 72H ■7. 82^4 20 '-J >3 200 18 36 50 I>s 67.68 2J^ 10 ''4 23!-i 89 12 29'.. (>sX 21' 77 'i 25 >5 250 18 36 62 ■x 83.91 '2H 10 i.M 23.'< 101 12 29>;; nX 21 895 100.17 2y, 10 •J4 23>< I '3 12 2g'A ,»9X 21 ■ 101 '<: 25 '5 350 22 54 58 I>« "7-77 2K 12 i>^ 27 104 14 34 Ji 77 24J^ 90 M 29^ 18 400 22 54 66 Ij^ 134.00 3 12 i.'4 27 112 14 34 ?i 85 2AX 98^ 29 j<; 18 500 24 63 72 IK 170.56 3 12 iK 30 122 16 40 14 92Ji i7i 87 '4 i\ 104 37 21 700 27 84 74 1>< 233.74 4 14 2 34 '31 18 4ih 97 J4 31 114 37 21 800 30 102 70 iK 268.48 4 14 2 38 '33 20 49 95 34 114 Ai'< 21 tyxi 30 102 80 i>i 306.85 4 "4 2 38 143 20 49 '05 .34 124 41 'i 21 1000 32 114 78 Ijo 334.36 4 18 2 40 ■43 20 51 103 34 124 42)-. 26 i;oo i' 114 94 'X. 402.97 5 18 2 40 ■59 20 51 119 34 140 42'; 26 1500 36 144 93 '>2 503.59 5 24 3 44 162 22 57 119 39 144 44 32 2(KJC> 36 144 124 •IX 671.80 5 24 3 44 192 22 58 .50 J9 ■75 44 32 300*1 48 258 104 '.'<; 1008 96 6 30 3 56 181 24 66 130 45 160 48 38 40(xj 48 258 138 1 <4 1338.87 6 30 3 56 211 24 66 164 43 194 48 38 5o<-io 60 402 111 ''A 1677.99 8 30 3 68 202 26 72 •43 47 «7S 52 38 6000 60 402 13s ''A 2038.51 8 30 3 68 226 26 72 167 47 199 52 38 A type of feed water heater which has been recently developed by Shutte and Koerting Co. for use in battleships, torpedo boat destroyers and places where saving of space is an item, is shown by the sectional cut which follows. In this type of heater, the water to be heated is sent through a narrow space between sets of corrugated tubes. The lower tube in the cut referred to shows one set of tubes in section. The steam which heats the water is on the outside of the larger corrugated tube and on the inside of the inner corrugated tube. The feed water is sent through these tubes under high velocity and, due to the fact that the water is broken up into a thin film, it is possible to heat it to within a very few degrees of the temperature of the steam. The loss in head in passing the water through the heater may be as great as 12 pounds. Dimensions of the different sizes of the heater, together with the horsepower rating may be obtained from the diagram and table which accompanies the same. NOTES ON POWER PLANT DESIGN 75 DIMENSION TABLE (Boil sr Horse Power Feed Water Size at 3# back Connections Steam Drain No. Pressure A B E FWI FWO S D 1 80 5'1" lOK" 4' VA" 1" 2" 1" 2 160 5'1" 14" 4' VA" lA" 3" 1" 3 330 5'1" 17" 4' VA" lA" 3" IJi" 4 500 5' 3" 21" 4' 2" 2" 4" lA" 5 650 5' 3" 22" 4' 2" 2" 4" m" 6 830 5' 3" 24" 4' 2" 2" 4" lA" 7 1000 5' 5" 24" 4' 2K" 3" 5" 2" 8 1150 5' 5" 27" 4'2M" 3" 5" 2" 9 1300 5' 5" 27" 4' 2A" 3" 5" 2" 10 1500 5' 7" 28" 4' 3" 3H" 6" 2A" 11 1660 5' 7" 28" 4' 3" 3^" 6" 2A" 12 2000 5' 7" 30" 4' 3" 3>^" 6" 2A" 13 2330 5' 9" 33" 4' 4" 4" 7" 3" 14 2700 5' 9" 33" 4' 4" 4" 7" 3" 15 3000 5' 9" 36" 4' 4" 4" 7" 3" 16 3300 5' 11" 40" 4' 5" 4>^" 8" 3H" 76 NOTES ON POWER PLANT DESIGN COOLING TOWERS The amount of water surface in a cooling tower working with forced air circulation varies from 23 to 27 square feet per I. H. P. More surface is needed in a natural draft tower than in a fan tower, in general the surface being double that of a forced draft tower. The amount of air needed depends to a large extent upon the humidity of the air entering the tower. The air leav- ing the tower is either saturated or nearly so. It is not advisable to send an abnormal amount of air through a tower, as the cost of the in- creased poAver needed to run the fan and the greater shrinkage due to evaporation, amount to more than the gain made by the increased vacuum on the engine, resulting from the cooler circulating water, will offset. The materials used inside of a cooling tower to expose as large a surface of cooling water as possible to contact with the air without at the same time obstructing the free flow of air, are tiers of the tile pipes 6" diameter, 2 feet long, used by the Worthington Company, galvanized iron wire screens set nearly vertical, used by the Wheeler Company, galvanized iron troughs set horizontally and arranged so that the water flows from trough to trough as it descends (Jennison tower), boards, brush, or other material. The amount of air to be supplied to a tower and the shrinkage of water from evaporation may be calculated approximately from the following equations: Z = weight of cooling water entering condenser per lb. of steam. E = weight of water evaporated from tower per lb. of steam condensed. Yc = cu. ft. of cold air entering tower per lb. of steam condensed. This air may enter by natural draft, or as is most often the case it may be sent in by disc fans. Yh= cu. ft. of hot air leaving tower per lb. of steam condensed = 1, i- e Y = the wt. of air entering the tower may be figured thus: Vc ^ Vc 29.92 X 12.39 Tc ^^, To .954 491.5 Pc P, Tc = absolute temperature of air entering. Pc = absolute pressure of air entering tower in ins. of mercury. If the excess pressure of the air entering the tower is measured by the difference of water level in a U-tube, Pc = the sum of the barometer reading and — r^ times the difference of water level. This excess pressure can usually be neglected. Qh and Qc are the heats of the liquid corresponding to the temperatures of the hot and cold condensing water. Yh and Yc are the weights of water carried by a cu. ft. of saturated air at temperatures th and tc respectively. See curves Z X {Qh- Qc) = ^% X .24 (th -tc) +r (.90 xVhYh- relative humidity x Vc Yc) th and tc are temperatures of air at top of tower and at entrance to tower, r is the heat of evaporation corresponding to the temperature of the air at top of the tower. The temperature of the air at the top of the tower is from 10 to 25 degrees lower than the temperature of the hot con- densing water taken where it enters the tower. NOTES ON PO^VER PLANT DESIGN 77 In making a calculation for a tower it is probably safe to assume a difference of 15 degrees. The air leaving the tower may be saturated or only partially saturated, the condition depending upon the amount of air sent in and the design of the tower. In general it is a good plan to assume that the air at the top of the tower is only 90% saturated and that the temperature of this air is 15 degrees lower than the temperature of the hot water entering the tower. These assumptions have been made in the calculations which follow. E = .90x Vk Yh - relative humidity x Vc Yc In the case of a jet condenser the steam condensed adds one pound to each Z pounds of cooling water entering the condenser. If E is greater than one pound then the excess must be supplied as make-up water. For a surface condenser E represents the make-up water. Problem. A cooling tower receives water from a surface condenser at 122° F., the water leaves the cooling tower at 90° F.; temperature of outside air 72°, relative humidity 80%. Temperature of condensed steam 95°, vacuum in condenser 25", barometer 29.7". Engine of 500 H. P. and consumes 20 pounds of steam per H. P. What is the amount of air needed per pound of steam condensed and what is the per cent loss of cooling water due to evaporation? 1053.2 - 63.1 990.1 31.8 = Z Vc X 566.5 X .00347 90.0 - 58.1 31.9 ^^^•l = .754 x'531.5 X -24 I (122 - 15) - 72 I + 1031.8 j .9 ^3^^ - .SVcX .00124 29.7 The figures .00347 and .00124 are the lbs. of water required to saturate a cu. ft. of dry air at 107 and at 72 deg. respectively. The figure 1031.8 is the value of the heat of vaporization at 107°. 990.1 = 3.036 Vc Vc = 326 cu. ft. E = (.00333 - .00099) Vc = .763 lbs. evaporation per lb. of steam condensed or per 31.8 lbs. of circulating water. This is „ p = .0240 or 2.40% shrinkage. As the first term of the right hand side of this equation ol . o evaluates .623 Fc it is evident that the heat carried off by the air is 5^1-5^ percentage of the total amount abstracted. This figiires as 20.5%; the heat taken out by evaporation being 79.5%. To illustrate more fully the use of the equation and to illustrate also the extra cost (at the cooling tower) of a high vacuum over a moderate vacuum, two cases will be taken up : First a condensing and cooling outfit maintaining a 28" vacuum and, second, a similar outfit maintaining a 26" vacuum. The illustration will be worked through for each case with relative humidities of the enter- ing air as 90, as 70, and as 50% First case — A condenser maintaining a 28" vacuum with hot condensing water at 95^ or 7 degrees below the temperature corresponding to the vacuum. The exhaust steam is assumed to contain 4% of moisture. The temperatin-e of the air may be taken as 72° and it will be assimaed that the tower is to cool the water to this temperature. For air 90% saturated at 72° the volume required per pound of steam = Vc may be cal- culated thus: To abstract the heat from a pound of exhaust steam 43.5 lbs. of cooling water would .78 NOTES ON POWER PLANT DESIGN be the minimum weight required, since 1000 heat units are to be abstracted from each pound of steam with an increase in temperature in the circulating water of 23°. ) ' 29.92 ] ' - .9 Fc X 0.0124 1000 = .143 Vc + 1046.6 (.00144 - .00112) Vc J 1000 = .143 Vc + .335 Vc Vc = 2100 cu. ft. The evaporation = .00032 x 2100 = .672 lbs. Of this total heat abstracted the heating of the air accounts for 30 per cent and the evaporation 70 per cent. Similar calculations for 70 per cent and for 50 per cent humidities give Per cent Cu. ft. air Evap. per lb. Per cent heat Per cent heat humidity- per lb. of of exhaust abstracted by abstracted by entering air exhaust condensed the air vaporization 90 2090 .672 30 70.0 70 1350 .770 19.4 80.6 50 990 .812 14.1 85.9 Second: Suppose that the vacuum to be carried is 26" with air at 72° and hot condensing water at 119° or 7 degrees below the temperature corresponding to the vacuum. Cold water at 72°; and 4 per cent moisture in the exhaust steam. The heat to be abstracted per pound of exhaust is 983 B. T. U. and 20.9 lbs. of cooling water is the minimum required per pound of exhaust. From calculations similar to the preceding it appears that the amounts of air needed and the evaporations are: lative Cu. ft. Evaporation Per cent heat Per cent heat nidity air in pounds abstracted by the air abstracted by vaporization 90 386 .737 22.5 • 77.5 70 350 .756 20.8 79.2 50 321 .773 ~ 18.7 81.2 The amount of water evaporated per pound of steam condensed is about the same in each case. In the first case with 70 per cent humidity the evaporation was .770 in 43.5 lbs. of water sent into the tower, or 1.8%. In the second case with 70 per cent humidity about 3.6%. The curve showing the pounds of water needed to saturate one pound of air at any tempera- ture may be constructed very quickly from values taken from any steam tables. Example. — The amount of water required to saturate one cubic foot of air at 88° F. is .002 lb. If the air was of a relative humidity of 60 to start with, then 40 x .002 would be the amount the air would take up in becoming saturated and the B. T. U. abstracted would be 1042.2 X .40 X .002 = .834 per cu. ft. of air. PER CENT OF ENGINE POWER REQUIRED BY COOLING TOWER FAN AND BY THE EXTRA DISCHARGE HEAD ON THE CIRCULATING WATER Referring to the first case already cited, with relative humidity of 70, 1350 cu. ft. of air were needed. Suppose a disc fan is to be used and a dynamic head of .3" of water maintained at the fan. As the static head is zero the velocity head will be .3". This velocity pressure corresponds at 70° to a velocity of 2200 ft. per minute. Suppose the NOTES ON POWER PLANT DESIGN 79 engine uses 14 pounds of steam per H. P. per hour, then the steam per minute is 14/60 lbs. and the cu. ft. of air sent through the tower is 14/60 x 1350. The H. P. input to the fan is, for this case, if 30 per cent is assumed as fan efficiency: of engine power. To this should be added the power due to pumping 14/60 x 43.5 pounds of cooling water per minute through an additional head of about 30 feet. This amounts to .00889 H. P. If the fan were driven by a small engine using 35 pounds of steam per H. P. hour and the circulating apparatus were also steam driven using 40 lbs. per H. P. hour, then the extra steam required by the cooling tower outfit would be 2 10 .050 X 35 + .0089 x 40 = 2.10 and -jj- = .15 or 15.0 per cent additional. A similar calculation for the second case with 26°" vacuum, 70% humidity with engine using 15 pounds of steam per H. P. hour gives: 15 Air per minute = ttkX 350 60 .3 X 5.2 X ^ X 350 H- ^- *^ ^^^ = 33000 X .30 = -^^^^ 20.9 x^ X 30 Extra H. P. on circulating pump = oonnn ^ .00472 If fan engine and circulating apparatus were steam driven then using same rate as before .0137 X 35 + .00472 x 40 = .668 .668 15 = .0445 or about 4.45% additional. If the cooling surface used in the tower offers much resistance to the free discharge of air from the fan through the tower, it may be necessary to run the fan at higher velocity which increases the work of driving. In the Wheeler Barnard cooling tower the cooling surface consists of galvanized wire screens placed in parallel vertical rows about 3" apart. Water is distributed to the tops of these screens bj^ U-shaped troughs each trough supplying two screens. In this way as each side of a screen is figured as coofing surface, 8 sq. ft. of surface is obtained per cubic foot of volume in the screen section of the tower. But little resistance is offered to the passage of air between the screens. From experiments made by the company it is found that ordinarily eleven feet of vertical length of screen offers sufficient evaporating surface to saturate the air. The tower is square or rectangular in section and the number of fans needed depends upon the size of the tower. The B. T. U. per hour per square foot of surface in a cooling tower apparently varies from 200 to 900. It is not possible to get figures for a square foot of surface which will apply to every type of tower since with different kinds of surface there is a variable amount of spraying; even with the same surface this spraying varies with the quantity of water flowing; and consequently there is available an unknown amount of surface besides that provided in the tower. A drop of water .178" in diameter weighs .75 grains and the surface of a number of drops suffi- cient to make a gallon would be about 54 square feet. Cooling towers are occasionally placed on the roof of buildings. By using a surface condenser 80 NOTES ON POWER PLANT DESIGN the extra work on the up leg of the circulating water is practically offset by the gain from the down leg and there is simply the friction hi the extra lengths of pipuig to make additional work for the circulating pump. Where one tower is used for a number of condensers having centrifugal circulating pumps it is advisable to have a separate discharge pipe from each centrifugal to the tower. Towers cost above the foundation from $2.60 to $4.00 per K. W. capacity. SPRAY NOZZLES By spraying water into the air a cooling may be effected through the evaporation of a part of the water just as was the case in the cooling tower. The total exposed surface of the sprayed jet meets less air per pound than in the cooling tower, and on this account it is often advisable to spray 30 to 50 per cent of the water a second time before sending it through the condenser. Generally spray nozzles of the size known as 2" are the most economical. The 2" size screws on to a 2" outlet; the opening in the nozzle tip being about .8". As many nozzles should be pro- vided as are needed to discharge the entire weight of condensing water under a pressure of not over 15 lbs. gage at the nozzle. The nozzles should be set from 8 to 10 feet apart if 2"; a greater distance if over 2". Where a considerable number of nozzles are used it is customary to have the water which is sprayed into the air fall back into an artificial pond one or two feet deep. When a number of nozzles are in use the aspirator action exerted by the jets causes a current of air to flow along the surface of the pond from the edge towards the centre. This current of air assists to some extent in the cooling. In some few instances spray nozzles have been put along the edges of a narrow brook and the falling spray caught on board fences inclined 30° with the ground and draining into the brook. There are one or two small plants where the cooling nozzles discharge on to the roof of the building. From tests made in the Engineering Laboratories of the Massachusetts Institute of Technology on the Schutte Koerting nozzles it seems that 1° The temperature of the water after spraying is more dependent upon the temperature and humidity of the atmosphere and upon the fineness of the spray than upon the initial tem- perature of the water. Therefore it is advisable to spray -the water as hot as may be without excessive steaming. 2° At high humidity, 80% or 90%, the temperature of the water, may be lowered to within 12° F. or 13° F. of the temperature of the air, with a total drop in temperature of 35° F.. to 40° F. 3° At low humidity 20% to 30%, the temperature of the water after spraying may be as much as 8° F. below the temperature of the air and the total drop in temperature 40° F. to 45° F. 4° The loss of water by evaporation is approximately .15 pounds per degree lowering of temperature per 100 pounds of water discharged, or a gross loss of about 6% for 40° F. lowering of temperature. In no case was the loss found to exceed 7%. The discharge of these nozzles was found to be as follows: Head in ft. Cu. ft. per Cu. ft. per min. Cu. ft. per mm. at base of min .. for 1" for 2" pipe for 3" pipe nozzle. pipe. Diam. Tip = = .800" diam. Tip = 1.181" diam, nozzle at tip .406" 25 1.782 6.736 14.83 30 1.952 7.379 16.24 35 2.109 7.971 17.54 40 2.254 8.521 18.75 45 2.391 9.036 19.89 50 2.520 9.526 20.97 55 2.643 9.991 21.99 60 2.761 10.44 22.97 65 2.873 10.86 - 23.91 NOTES ON POWER PLANT DESIGN 81 Tempera/'ure of /J//-. 82 NOTES ON POWER PLANT DESIGN CENTRIFUGAL PUMPS Centrifugal pumps either single or multistage are replacing the reciprocating piston pump for pumping condensate, circulating water and feed water. Centrifugal pumps should have the impeller designed for the conditions of suction head, de- livery head, speed and capacity the pump is to work under. Well designed pumps give efficiencies of from 75 to 80 per cent. The centrifugal pumps of five stages used in the high pressure fire service in the City of New York showed under test efficiencies of 75 and 77 per cent when working with delivery pressures of 300 lbs. Centrifugals are sometimes arranged so that two pumps driven by the same shaft may deliver into a common discharge, thus giving a large quantity at a moderate pressure; or the discharge of one may be sent into the suction of the other and the delivery pressure increased ; the quantity of water being, of course, decreased. If the efficiency of each pump is 71 per cent the efficiency of the outfit used either way will remain practically the same. In pumping circulating water from a jet condenser to a cooling tower, as there is less than atmospheric pressure on the suction side of the pump, the total static head should be calculated from the difference of the absolute pressures at entrance to and exit from the pump. To this head expressed in feet should be added an amount sufficient to allow for the friction and other losses. The efficiency of the smaller pumps is probably not over 60 per cent. The velocity of water in the discharge pipe should not exceed 400 feet per minute; 6 feet a second is a velocity quite commonly allowed. Although a number of centrifugal pumps connected to jet condensers may work successfully when piped to a common discharge leading to a cooling tower, it is always safer to connect each centrifugal with the tower through a separate pipe. Turbine driven stage centrifugals are quite generally used now in the large boiler plants in place of the steam or power driven reciprocating feed pump. The hot feed water must conie to the pump under a head. The efficiency of centrifugals used as feed pumps may be assumed to be between 40 and 55 per cent; 45 per cent has been used as the efficiency in the calculation for horse power input given below. The maximum horse power input required by a centrifugal boiler feed pump is r^ X T , T- J T^ TT Ti • X 2.32 X Gage Pressure x 30 x Max. Boiler H. P. Centrifugal Feed Pump H. P. mput = 33 000 x 60 x 45 7.8 X Gage Pressure x Max. Boiler H. P. lopoo ^ "PP^^^- Centrifugal pumps have to be primed (filled with water) before starting. This may be done by putting a foot valve on the end of the suction pipe and then filling with water under pressure, the air at the top of the casing being vented, or the pump may be primed by closing a valve in the delivery pipe and then exhausting air from the top of the pump casing by a steam ejector, a water ejector or by means of a connection to a dry vacuum pump. As a foot valve offers considerable resistance to the flow of water it is to be avoided whenever possible; should it be necessary to use a foot valve one at least two sizes larger than the suction pipe is to be recommended. Centrifugal pumps of large capacity either turbine driven or motor driven have been used as pumping units in municipal pumping stations. While it is not possible to get as high a duty as may be obtained with a reciprocating pump the first cost is only about one third that of the recip- rocating and the number of operatives required to run the centrifugal outfit is less. These pumps should have both a check valve and a hydraulically operated discharge valve in the discharge pipe. In shutting the pump down the discharge valve is closed before the power NOTES ON POWER PLANT DESIGN 83 is shut off. While the pump might be stopped without closing this valve and the check valve de- pended upon to prevent a flow-back from the reservoir or standpipe, should this valve stick open and close suddenly the water hammer blow resulting could not be withstood by the pump or the piping. Pumps used for this service should have suitable characteristics. The pressure should not build up over 15 per cent when the discharge valve is closed with the pump running. Following are some characteristic curves obtained from test data on different types of pumps. All of these curves were plotted for a constant speed. The pumps would have different characteristic curves at every speed. These curves were plotted at the most economical speed of the unit. Fig. 1 shows the curves taken from a Worthington Tri-rotor pump. This pump was con- nected to an 800 H. P. Curtis Turbine and installed for the Carnegie Steel Company for pump- ing dirty water. This pump has no discharge valves and gives an efficiency of 74% which is high for a volute pump. Fig. 2 gives the curves of a DeLaval pump which are notable in that the power taken by the pump decreases rapidly after the point of maximum efficiency is reached. This allows of the installation of a motor which is just capable of handling the full load of the pump. Fig. 3 shows the characteristic curves for a Worthington Boiler Feed Pump installed at the Commonwealth Edison Company. The pump is of the double suction type in which water it admitted to both sides of the impeller. This pump has three stages and is connected to a 150 H. P. Curtis Turbine running at 2350 R. P. M. The feature of the characteristics is the wide range of discharge over which the efficiency is high. Fig. 4. The set of curves was taken from a double stage Alberger Fire Pump which runs at a speed of 1400 R. P. M. and requires a 90 H. P. motor. The high efficiency of this pump is notable for a double stage pump. These curves also show what would take place if the discharge piping should fail while the pump was in operation. The head would, of course, fall nearly to zero and the discharge would go up rapidly. The horse power taken from the motor under these con- ditions would increase rapidly due to the marked decrease in efficiency. In this set of curves the power supplied would be 107 at zero head and hence the 90 H.P. motor must be capable of sub- taining this overload of 17 H. P. for a short time. All centrifugal pumps operating under suction head must be primed before they can be started. All the passages of the pump must be completely filled with water before the pump will "pick up." It is dangerous in many cases to allow a pump to be started without priming, since many pumps are so constructed that they depend on the presence of water for running balance and inter- ference at the clearance spaces may destroy the pump if water is not present. The theory of centrifugal pumps with reference to the blade angles, calculation of pressures in the casing, and other points of design, is extremely complicated and based entirely on assump- tions as to existing conditions in the pump. The entrance angle of the impeller depends upon what assumptions are made in regard to the direction of absolute velocity at entrance. This velocity is usually assumed to be radial, and is taken as 15 feet per second for pumps without lift and 10 feet per second for pumps with lift. The construction of the blade is arbitrary to some extent. Some manufacturers use the arc of a circle, others an involute, and still others a logarithmic spiral. In the accompanying pruit oc represents the angle of entrance of the impeller and U the angle of entrance to the guide vanes. The effect of the shape of the blades on the exit and entrance velo- city diagrams is also shown in the print. The De Laval centrifugal is made with the angle at exit 20° with the tangent. 84 NOTES ON POWER PLANT DESIGN In order to estimate the loss of head through friction in piping the accompanying chart taken from the catalogue of the De Laval Co. is quite convenient to use. If the quantity of water passing through the pipe and the size of the pipe are known, the fric- tion head in 1000 feet length of pipe is found by laying a straight edge through the known points of the scales representing capacity and size of pipe. The friction head is then read off on the third scale at the point of intersection between the straight edge and this scale. The values obtained from this chart are based upon the Hazen-Williams formula: 0.63 /;jX 0.5* 0.12 V = cr ( -y- 1 X 10 where v is the velocity in feet per second, r is the hydraulic radius = t in feet, h the fric- tion head and / the length of piping, c is a constant depending upon the roughness of the pipe and upon the hydraulic radius. The formula can also be written 147.85 _Q_y-852 where h is, as before, the friction head in feet for / = 1000 ft., Q is the water quantity in gallons per minute and d is the diameter of pipe in inches. The chart is based upon a value of c = 100, which is mostly used and considered safe for ordin- ary conditions. 1.852 For other value of c the figure obtained from the chart should be multiplied by i^ = ( For information regarding coefficient c for different kinds and size of pipes, and also value of K for different values of c, see table below. Size of Pipe, inches 2 to 3 4 5 6 8 10 12 16 20 24 30 36 42 48 54 60 c K Condition of pipe Year of Service for Cast Iron Pipe 140 .54 Very smooth and straight and Brass, Tin, etc. 00 00 00 00 00 00 ■ 00 00 00 00 00 00 00 00 00 130 .61.5 Ordinary straight Brass or Tin 120 .715 Smooth new Iron 4 4 4 5 5 c 5 5 5 6 6 6 6 6 6 110 .84 10 10 10 11 11 11 12 12 12 12 12 12 100 1.0 Ordinary Iron* 13 14 15 16 17 17 18 19 19 19 20 20 20 20 20 90 1.21 26 27 28 29 30 30 30 30 31 31 80 1.51 Old Iron 26 28 30 33 35 37 39 41 42 43 44 45 45 46 47 60 2.58 Very rough 45 50 55 62 68 40 5.45 Badly tuberculated 75 87 95 00 indicates the very best cast iron pipe laid perfectly straight, and when new. indicates good new cast iron pipe. NOTES ON POWER PLANT DESIGN 85 /Sooots O.I - /ooooo Soooo Qooeo 70000 60000 -Soooo -4.0000 - 30000 -,^0000 /Sooo —/oooo Sooo sooo '7000 6000 —Sooo -4ooo -3ooo -Zooo /Soo -/ooo 900 Soo Too 600 — Soo 4So —400 3SO —3 00 .:?oo /SO -100 9o So 7o 60 ^So ■ S6 ■9o ■S4 •73 -7Z -66 .60 .£4 -4-3 -36 -Jo -^o -/3 ■/£ ■/4 1? ■/Z ■/o ■ 6 -S -3 \ \ \ oJS 0.3 OA oS \ \ 0.6 — £7.7 0.8 0.9 /.O — /.£ - s 3.5- 4- 4-5- 10 ■ Zo 30 40 r ^ Chart for determining resistance of pipes to How of water, 86 NOTES ON POWER PLANT DESIGN /60 aoo Q A*>e> gooo 3000 400a S009 6OO0 fooo 8000 Sooo /ooco /^eea /iooo /3000 /fooo /javo /sooo //oati NOTES ON POWER PLANT DESIGN 87 /80 /GO 8000 aioo geoo eaoo s&oo 3^00 3400 ^600 NOTES ON POWER PLANT DESIGN no /ao zoo 300 400 JOO 600 SCO NOTES ON POWER PLANT DESIGN 89 90 NOTES ON POWER PLANT DESIGN i/i = Linear i^e/oc/ty of irnpe/Ier at outer edge. Ttl = " " " " " inner " . Vea = Abso/ute ye/ocity at entrance (TaJcen rac//a/). Vrw== Veioc/ty of y/ater reiative to wbeei. Vab = Absoiute exit veiocity from impeiier. I^adiai y^eiociiy at entrance is usuaily fal^ 23 28H 22K mvz 5x15 mu 62 46K 31 40>^ ^m 22^ 6x18 80 60 40 49>i 40H 31J^ 8x18 120 90 60 72 57 48 8x20 105 70 84 66H 56 8x24 135 90 120 96 72 10x24 172H 115 150 120 90 , The horse-power required for handling anthracite coal may be determined from the follow- ing formula, this taking no account of gearing or other driving connections. H.P. = ATL + BWS 1000 T = net tons per hour. L = length, centre to centre, in feet. W = weight of chain and flights (both runs) in pounds. S = speed per minute in feet. 92 NOTES ON POWER PLANT DESIGN A and B are constants depending on the inclination from the horizontal. (See value below.) Hor. 5° 10° 15° 20° 25° 30° 35° 40° 45° A 0.343 0.42 0.50 0.585 0.66 0.73 0.79 0.85 0.90 0.945 B 0.01 0.01 0.01 0.01 0.009 0.009 0.009 0.008 0.008 0.007 The common working speeds are from 100 to 200 feet per minute, and the capacities are as shown by the table, these conveyors in some cases handling upwards of 500 tons per hour. As an illustration, suppose it is desired to elevate hard coal 50 feet by a flight conveyor inclined 30 degrees, the capacity of the conveyor being 30 tons per hour at 100 feet speed per minute. From the table it is evident that at a speed of 100 feet per minute the flight should be 6 inches by 18 inches and spaced 24 inches apart. The length of the conveyor, centre to centre, would be at least 100 feet. Calling the weight of the chain 20 pounds per foot, and the weight of the flights spaced every 2 feet, 40 pounds, as given, the total weight per foot figures as 40 pounds. Substituting, in the formula given, the „ p _ 0.79 X 30 X 100) + (0.009 x 200 x 40 x 100) " 1000 = 7.77 >. PIVOTED BUCKET CARRIERS Where the design of the plant requires conveying machinery adapted to the combined service of handling coal and ashes, the pivot-bucket carrier is hard to excel. The handling of ashes is very hard on conveying machinery, and the construction of the carrier permits replacement of the several parts as corrosion or wear proceeds. Pivoted-bucket carriers for elevating coal in power-plant service have become quite popular. Their advantages are slow speed, silent operation, adaptability to change of direction without transfer, high efficiency, and easy renewal of worn parts. Their disadvantages are danger of buckets sticking or upsetting and jamming in the supports, and the difficulty of preventing spill at the loading and turning points. Protection against jamming may be had by connecting with the driving machinery through a safety pin whose margin of strength beyond the power requirements is very slight; or better, by designing the supports so that the buckets will clear in whatever posi- tion they may come around. _ _ Uncleanly loading is guarded against in various ways in the several latest designs of carriers, of which the following may be noted. In the Hunt carrier, the buckets are spaced an inch or so apart and are loaded by a special device consisting of a series of connected funnels at the loading chute, in synchronism with, and dipping into, the carrier buckets, vso that each bucket receives its proper charge only. The Webster carrier has buckets with carefully planed lips, the pitch of the buckets being very slightly less than the pitch of the carrier chain links, thus depending on close contact to eliminate the leakage. The McCaslin carrier uses overlapping buckets. These lap the wrong way after tripping for discharge, and are reversed by a "righting mechanism" before again passing the loading point. The Peck carrier uses overlapping buckets similar to the McCaslin, but they are attached to the links extended beyond the points of articulation. This arrangement unlatches the buckets at the turns by giving them a path of greater radius than the chain joints, thereby doing away with a righting device otherwise necessary with the overlapping bucket. None of these devices for preventing spill at the loading and turning points are particularly effective. The difficulty is inherent in this type of conveyor whose many advantages, however, far outweigh their defects. The alternative of the pivoted-bucket carrier for handling coal is the standard arrangement of an elevator with rigid steel buckets discharging into a flight conveyor which crosses above the NOTES ON POWER PLANT DESIGN 93 bunkers, and is provided with discharge gates at convenient intervals ; or instead of a flight con- veyor, a belt with movable tripper. This is a well tried-out system, thoroughly reliable, and by many preferred to the run-around carrier, on the ground of lower first cost and simpler con- struction. The elevator conveyor system is not adapted to handling ashes, which, however, should be tr.ken care of by separate machinery whenever possible to do so. Diagram Showing Operation of the Peck Carrier, The general arrangement of a "rectangular" pivoted bucket conveyor is shown by the accom- panying cut. Coal discharged from a car or from a cart falls into a crusher where the large lumps are broken up. From the crusher the coal is taken directly into the conveyor or into the feeding mechanism which fills the conveyor. Somewhere in the system there must be a tightener, which in this cut is shown as located at the lower right-hand corner. The reciprocating feeder consists simply of a movable plate, at the bottom of the hopper, which is pushed forward and back through the action of an eccentric. On the forward stroke coal is fed into the crusher. The length of the plate is such that coal in the hopper will not flow over the left-hand edge when the feeding plate is still. When coal is discharged directly through the track hopper, feeder and crusher into the con- veyor buckets as shown in the cut, the track must be from 10 to 12 feet above the bottom run of the conveyor. Where there is not sufficient depth for this arrangement an apron feeder (see illustration) would be used to elevate the coal to the crusher. The speed of the apron must be regulated to suit the capacity of the carrier or a reciprocat- ing feeder may be inserted between the hopper and the apron. 94 NOTES ON POWER PLANT DESIGN STANDARD SIZES AND CAPACITIES OF PECK CARRIERS For a speed of from 40 to 50 feet per minute with pitch of chain 24 inches the capacity is with buckets 24" x 18" 40 to 50 tons coal per hour with buckets 24" x 24" 55 to 70 tons coal per hour with buckets 24" x 30" 75 to 100 tons coal per hour with buckets 24" x 36" 90 to 120 tons coal per hour XrHIMUM T CLEARANCE General Dimensions, 24-inch Pitch Carriers NOTES ON POWER PLANT DESIGN 95 The general dimensions of a Peck carrier 24" pitch may be obtained from the cuts shown on the preceeding page. The power required for driving a rectangular conveyor similar to those referred to may be obtained from the following formula which is based on tests made on a number of such conveyors. H. P. = .000085 X tons per hour x speed in feet per minute x elevation in feet. The power run- ning empty is approximately one-half of the power for loaded condition. The power required for an apron feeder may be calculated from the same formula. A reciprocating feeder requires about 5 H. P. A coal crusher of 30 tons capacity per hour requires a floor space of 7' x 4'-6" and height of 3 feet overall when set on a cast iron base and 2 feet when set as shown in the cut illustrating the apron feeder. It requires 5 H. P. to drive it. A 50 ton crusher 10 H. P. with floor space 9' x 5' and heights of 3' 6" and 2' 6" according to setting. A 70 ton crusher 15 H. P. space 9' x 6' and heights of 4' 6" and 3' 6". The accompanying cut shows, a crusher with hopper and casing removed. A V bucket elevator conveyor is shown by the sketch on the page following, diagrams A-F indicate some of the possible arrangements. The small 96 NOTES ON POWER PLANT DESIGN 'I -,^-^-cNj==^^-j:^iAsr; -i^^^-^i^jg^ f5=** W **=^ f?^ ^ fP^TT? ^^ Coal is fed to the lower run. by a plain chute, is then pushed along the run till the vertical is reached, where the coal is carried inside the buckets; on the upper run the coal is pushed along until it reaches an opening through which it is discharged. A 40 ton V bucket elevator installed at the Bergner and Engel Brewing Co.'s plant and a 40 ton coal elevator and flight conveyor at the U. S. Arsenal at Frankford are shown by the cuts which follow. U. S. Arsenal. Frankford,. Phila. NOTES ON POWER PLANT DESIGN 97 A locomotive crane operating a grab bucket is frequently used to move coal from a storage pile onto a belt or bucket conveyor, for unloading barges, etc. -►--»— »-->•-»->— '>^- •<~« CONCRETE ■¥ STCEL COAL BUNKEII CAPACIir lOOOTONS WW \oo& Bergner and Engel Brewing Co., -Phtladelpiita, Pa. 40 ton per hour v-bucket elevator. Conveyor for coal; push car and electric skip for ashes. Such cranes are either mounted on a car like a platform car or elevated as shown by the accom- panying figure. For unloading barges and hoisting coal to an elevator a tower known as the Boston tower is quite generally used. This handling device consists of a grab bucket operated from the tower, which has projecting out a distance of 20 or 30 feet, a horizontal arm on which travels a movable carriage through which run the hoisting ropes operating the grab bucket. This carriage may be moved out or in while the grab is being raised or lowered. 98 NOTES ON POWER PLANT DESIGN BELT CONVEYORS If coal is to be conveyed any considerable distance a belt conveyor would be used. Belt con- veyors will carry coal at an angle as great as 20° and may be built to handle any quantity of coal. The following table gives the capacity, maximum size of lumps, and advisable speed for the different widths of belts. BELT CAPACITY AND SPEED Capacity in Cubic Maximum Advis- Feet at the Maxi- Width of Maximum Size able Speed in mum Advisable Belt. of Pieces. Feet per Minute. Belt Speed. 12 2 300 1380 14 2K 300 1890 16 3 300 2460 18 4 350 3640 20 5 350 4480 22 , 6 400 6200 24 8 400 7400 26 9 450 9810 28 12 450 11250 30 14 450 13050 32 15 500 16500 34 i6 500 18500 36 18 ■ 500 21000 38 19 550 25300 40 20 550 28050 42 20 550 30800 44 22 600 37200 46 22 600 40800 48 24 600 44400 When the quantity to be conveyed is small, and the pieces large, the size of the material fixes the width of the belt, and the speed should be as low as possible to carry safely the desired load. When the quantity is great, the capacity fixes the width, and in this case also, the speed should be as low as possible. A belt at slow speed may be loaded more deeply than one at high speed, and when a narrow belt is run much above the advisable speed, the load thins out and the capacity does not increase as the speed. The maximum length of the different widths of conveyors is determined by the fibre stress in the belt, and is, therefore, closely related to the load and speed. Naturally level conveyors may be built longer than those lifting material. Conveyors 1000 feet from centre to centre, hand- ling 400 tons per hour, have been most satisfactorily operated. Another important factor in the design of conveyors operated at high speed and handling large quantities is the flow of material in the chutes. A 36-inch conveyor handling 750 tons of coal per hour, with a belt speed of 750 feet per minute under a 10,000 ton pocket, could not be loaded from a single chute, because it was not possible for the coal to attain a speed of 750 feet per minute in the chute. It was necessary, therefore, in order to obtain a full load, to open seven gates, each placing a layer of coal on the belt until the desired load was obtamed. During a test this belt carried about 800 tons per hour. NOTES ON POWER PLANT DESIGN 99 POWER REQUIRED FOR BELT CONVEYORS The power required to drive a belt conveyor depends on a great variety of conditions, such as the spacing of idlers, type of drive, thickness of belt, etc. In figuring the power required, it is important to remember that the belt should be run no faster than is required to carry the desired load. If for any reason it is necessary to increase the speed, the figure taken for load should be increased in proportion and the power figured accordingly. In other words, the power should always be figured for the full capacity at the chosen speed, as follows: C = power constant from table. T = load in tons per hour. L = length of conveyor between centres in feet. H = vertical height in feet that material is lifted. (S = belt speed in feet per minute. B = width of belt in inches. For level conveyors, H. P. = For inclined conveyors, H.P. C xT xL 1000 C xTxL ^TxH 1000 1000 Add for each movable or fixed tripper horse-power in column 3 of table below. Add 20 per cent to horse-power for each conveyor under 50 feet in length. Add 10 per cent to horse-power for each conveyor between 50 feet and 100 feet in length. The above figures do not include gear friction, should the conveyor be driven by gears. POWER REQUIRED FOR GIVEN LOAD 1 2 3 4 C C H.P. Fcr Material For Material Required for Weighing from Weighing from Each Movable Minimum Maximum Width 25 lbs. to 75 75 lbs. to 125 or Fixed Tripper Plies of Plies of of lbs. per lbs. per Belt. Belt. Belt. Cu. ft. Cu. ft. 12 .234 .147 Vs 3 4 14 .226 .143 K 3 4 16 .220 .140 M 4 5 18 .209 .138 1 4 5 20 .205 .136 IM 4 6 22 .199 .133 1^ 6 6 24 .195 .131 Wi 5 7 26 .187 .127 2 5 7 28 .175 .121 2J€ 5 & 30 .167 .117 23^ 6 8 32 .163 .115 2M 6 9 34 .161 .114 3 6 10 36 .157 .112 3J4 6 10 With the load and size of material known, choose from the capacity table the proper width of belt and proper speed. The above formulae give the horse-power required for the conveyor when handling the given load at the proper speed. With the horse-power and the speed known, the stress in the belt should be figured by the following formula in order to find the proper number of plies. 100 NOTES ON POWER PLANT DESIGN Stress in belt in pounds per inch of width = — ^ — ~ ~ S X B With this value known, the number of plies may be determined, using 20 pounds per inch per ply as the maximum. Columns 4 and 5 of this table give the maximum and minimum advisable plies of the different widths of belt. Belts between these limits will trough properly and will be stiff enough to support the load. Belt conveyors may be driven from either end. Somewhere in the system there must be a tightener to allow for the stretch of the belt. The troughing idlers should be placed dependent upon the weight of material carried as f oUows : For belts 12 to 16 inches wide, from 43^2 to 5 feet apart; For belts 18 to 22 inches wide, from 4 to 4}^ feet apart; For belts 24 to 30 inches wide, from 33^ to 4 feet apart, and For belts 30 to 36 inches wide, from 3 to 33^ feet apart. The life of the belt depends a great deal upon the care which it receives, upon the material handled, and upon the quality of the belt to begin with. In general the life of the belt may be taken as from three to eight years. THE DARLEY CONVEYOR A system for handling coal or ash by a current of air flowing in a pipe has been in use in some plants during the last three years. A description of a system arranged for handling ash will show the method of operation. A pipe is laid under the floor in front of the boilers with an opening through the floor into the pipe in front of each ash-pit door, each opening being closed unless ash is being hauled from the ash-pit into it. The end of the pipe under the floor is open to the air. The other end of this pipe connects with a riser which leads up to the top of a closed steel storage tank in which the ash is to be stored. An exhaust fan or a Root exhauster draws air out of the tank, thus creating a flow in the pipe in front of the boilers. Any ashes, clinker, or even bricks dumped in through the holes in front of the boilers will be carried along by the air and delivered into the closed tank elevated 20 to 40 feet above the boilers. After the exhauster has been stopped the ashes may be discharged from this tank into a car or cart by opening an ash valve in the bottom. To quench the hot ash and to prevent dust from being drawn over into the exhauster, a jet of water is sent in on the ash as it is entering the closed tank. The fittings, especially those at the corners where the direction changes wear rapidly. The elbows are made with renewable chilled backs or in some cases a tee is used in place of an elbow. The plugged end of the tee filling up with ash causes the wear to come on the ash. COAL BUNKERS Coal bunkers may be of the cylindrical type with conical bottom ; of the parabolic type made either of steel plate lined or unlined with concrete or of suspended steel straps with reinforced concrete carryi^j.g the load between the straps, of the structural steel type carried on girders running either parallel with the boiler fronts or on cross girders at right angles to the boiler fronts; the steel being protected by a reinforced concrete lining. It is difficult to make a calculation of the stresses in the girders supporting a coal bunker, 1st, on account of the unequal and variable loading and 2nd, because the coal may act like a dry sand under certain conditions and again under other conditions like moist earth. A treatise on walls, bins and grain elevators by Ketchum contains the best information available on this subject. The parabolic type of bunker is easy to construct and brings no eccentric load of any mag- nitude to the columns carrying it. NOTES ON POWER PLANT DESIGN 101 A simple method of drawing a parabolic for any sag and span is shown by the illustration. The actual curve is slightly different from a parabola. The coal may be heaped from the edges towards the centre of the span at an angle depending upon the angle of repose of coal which is from 35° to^40°. If D = the depth of the curve S = the span C = the capacity per foot of length X = zero at the lowest point of the curve. The correct equation becomes 2D F = -9^ (3X2 _ 2XA S J The capacity when filled level full is per foot of length C = .625 DS. The supporting forces, the thrust brought to the compression members placed between the columns at the top and the tension in the upper ends of the plate, may be found graphically. The total horizontal tension in the plate at the bottom is the same, as the total compression carried to the compression members at the top. A parabolic pocket known as the Brown is constructed of steel straps, bent to the correct shape, riveted at either end to channel bars attached to the columns. These straps carry the load and are spaced from 3 feet to 4 feet 10 inches according to the weight to be carried. On these straps a special crimped steel sheet known as "ferro-inclave" is laid as a reinforcing material and a thickness of concrete from 2" to 4" plastered over the inside and a similar but thinner coating on the outside. A section of "ferro-inclave" drawn full size is shown. Where the coal valves are attached, a piece of steel plate is fastened to the straps as shown by the illustration. The "Baker" suspension type has a rigid bottom carried by suspension rods spaced longitudin- ally at such distances as the load warrants. Between the suspension rods unit reinforced concrete slabs having rounded ends form the sides of the bin. The bottom may be constructed as shown or made up of unit slabs like the side. This method of constructing the sides allows of a bending of the rods, due to the loading of the pocket, without cracking the lining. 102 NOTES ON POWER PLANT DESIGN NOTES ON POWER PLANT DESIGN 103 rr- wk M \ ftm'mre, rn/^tire /.:// \\ ■%v- ¥^^N; /j/pJ^ ^ \. ^^^T / ^'""' ^°^™^ /«.. ^ . &r roy 7^1^^ SaTF ^ '"i^^r / mrStcTii/n Tff" Sv'^r^"'^ Mtniet ^/ Unit Concrete Slab Bin. "Baker" Suspension Type. Coal may be taken from the coal pocket overhead into a weighing hopper and from this discharged to the stoker through a spout in front of each boiler. The end of the spout is frequently spread out fan like and known as a spreader. The nozzle type is preferable however. The cut shows a spout with nozzle and with a swivel or universal joint at the top. The fireman by means of the handle directs the coal to any part of the stoker reservoir and fills same evenly. Movable weighing hoppers of capacity up to one ton may be installed and operated from the floor in plants of moderate size (see illustration). In large plants a motor driven crane carries a weigh- ing hopper of larger size which travels under the coil pocket over the firing aisle and automatically records the weight of coal fed to each stoker. i 104 NOTES ON POWER PLANT DESIGN NOTES ON POWER PLANT DESIGN 10^ Cuts of two different weighing hoppers and a number of coal valves taken from Steam Boilers are given. Volume of Ton of Coal Cu. Ft. Soft coal 41 to 43 Buckwheat or Pea Nut Furnace Size Coke Ash dry not packed 37 34 36 76 48 to 50 ..^% 106 NOTES ON POWER PLANT DESIGN FOUNDATIONS CONCRETE FLOORS, WALLS, ETC. The type of foundation used will depend upon the character of the soil and upon the load to be brought to the soil. Baker in his Masonry Construction gives the following safe bearing loads of soils. These values have been generally accepted. Tons per sq. ft. Min. Max. Clay in thick beds always dry ...... 6 Clay in thick beds moderately dry Clay soft ..... Gravel and coarse sand well cemented Sand dry, compact, well cemented Sand clean dry . . . . . Quicksand, Alluvial soils 4 1 8 4 2 .5 8 6 2 10 6 4 1 If the footing is spread sufficiently so that the load is carried by the soil it is customary to decrease the cross section of the footing as the depth decreases. <-o- <-o-^ With a 1-2-4 concrete the allowable offset is for a pressure on the soil of .5 ton per sq. ft lAt, for a load of 1 ton .8^ and for a load of 2 tons .bt where t is the thickness of the lower section of the footing. In many cases, especially where the load coming to the footing is not the same per foot, as for example in the setting of a water tube boiler, it is customary to reinforce the footing with steel rods or with steel beams buried in the concrete. If the land on which the structure is to be built, is made land, it will probably be necessary to put in piles to support the footing. The piles may be either wooden or concrete. The wooden piles cost for oak 20 to 30 feet long 6" top 12" butt 17 cents per foot of length; oak 40 to 60 feet long, 21 to 25 cents per foot of length; spruce, 20 to 30 feet 15 cents per foot of length. The cost of driving a pile and cutting off is about 9 cents a foot. Concrete piles cost about $20 for a 40 foot length as against $9.50 for wooden piles; the bear- ing power of a concrete pile is however 2.5 times that of a wooden pile. Wooden piles should not be driven closer than 30" on centers. The safe bearing load of a wooden pile may be figured with more or less uncertainty by what is known as the Wellington or the Engineering News formula: P = safe load in lbs. (factor of six used) M = weight of drop hammer in lbs. h = fall of hammer in ft. s = penetration or sinking in inches at last blow. This to be measured when there is no appreciable rebound of the hammer and the head of the pile is not broomed. NOTES ON POWER PLANT DESIGN 107 If there is a rebound the drop of hammer should be reduced. 2Mh P = s + 1 Illustration Hammer = 3000 lbs. Drop in ft. = 10 Penetration = 3" P = 15,000 lbs. BRICKS A mason and laborer will lay 1000 to 1500 bricks per day in a wall averaging 10" to 12" thick. The cost of labor per 1000 bricks laid, including mason and helper and cost of erecting stagings is from $8.00 to $8.50. Bricks cost from $7.50 to $10.00 per 1000 and a thousand bricks will lay about 2 cubic yards of masonry. It takes about 20 bricks 83^" x 4" x 23^" per cubic foot; the masonry weighing 125 lbs. per cu. ft. In a power house the floors are usually of reinforced concrete on steel beams. The boiler room floor is generally figured for 250 lbs. live load and the engine or turbine room for 400 lbs. live load. The dead load of various types of floors may be estimated from the following approximate data : the weights are given per sq. ft. of surface. Wooden wearing surface Granolithic finish Cinder filling Stone concrete . Cinder concrete Plaster, 2 coats 4 lbs. per inch thick 12 lbs. per inch thick 5 lbs. per inch thick 123/^ lbs. per inch thick 9 lbs. per inch thick 5 lbs. per inch thick The dead load of any roof may be estimated from the following 5 ply felt and gravel roofing 3 ply ready roofing Slate 3/16 thick Clay tile Tin roofing Copper roofing . Corrogated iron Dry cinders 6 lbs. lib. 73^ lbs. 12 lbs. lib. 2 lbs. 3 lbs. 4 lbs. The minimum live loads, for roofs pitching less than 20° vary from 30 to 50 lbs. per sq. ft. according to different City Bldg. Laws. For a pitch greater than 20°, 25 to 30 lbs. should be used. For light floor loads a 1-3-6 concrete might be used. This mixture might also be used in walls carrying but small loads. For heavy loads or for columns a 1-2-4 or richer mixture would be used. 108 NOTES ON POWER PLANT DESIGN REINFORCED CONCRETE FLOORS Various types of reinforcing rods, woven wire fabric, welded wire fabric and expanded metal are used as reinforcing material in concrete floors. The woven fabrics and the expanded metal are made in certain definite sections and from tests which have been made on slabs of different thick- ness, the makers of the various reinforcing fabrics have constructed tables some of which have been given in these pages. While tables might have been given for the strength of slabs reinforced by rods of one type or another, it was felt that one had better make his own calculations for such cases. The formulae generally given for figuring reinforced concrete beams and slabs are derived on the assumption that (1) the tensile resistance of the concrete may be neglected and (2) that the stress diagram for the concrete is a straight line up to the safe compressive strength of the concrete. The formulae and notation given below are practically as given in Turneaure and Maurer's Principles of Reinforced Concrete Construction. See also Baker's Treatise on Masonry Construc- tion, Report of Joint Committees of Engineering Societies and Taylor & Thompson's Reinforced Concrete. fs = fibre stress in steel per sq. inch taken as 16 to 18,000 lbs. fc = fibre stress in concrete, the maxinjum compression per square inchi at outer face; for 1-2-4 stone concrete from 600 to 700 lbs. ; for 1-2-4 cinder concrete from 300 to 400 lbs. Es = elongation of steel per inch of length due to stress fs per sq. inch. Ec = shortenmg per inch of leng-th of the concrete due to the stress /c per sq. inch. Es ?= modulus of elasticity of steel. Ec = modulus of elasticity of concrete in compression. pi n = r~f generally taken as 15 for 1-2-4 stone concrete and as 30 for 1-2-4 cinder concrete. Ec T = total tension in the steel at any section of the beam. C = total compression in the concrete at any section. Ms = resisting moment as determined by the steel ; inch lbs. Mc = resisting moment as determined by the concrete; inch lbs. M = bending moment or resisting moment in general; inch lbs. h = breadth of rectangular beam or slab in inches. d = distance in inches from the compressive face of the concrete to the plane of the steel. K = ratio of the depth of the neutral axis of a section below the top, to the distance d, generally taken as .375. j = ratio of the arm of the resisting couple to the distance d. A = area of cross section of the steel. P = — — = the steel ratio generally from .007 for a 1-2-4 cinder concrete to .0122 for a 1-2-4 stone concrete. Since cross sections that were plane before bending remain plane after bending the unit defor- mations of the fibres vary as their distances from the neutral axis. ■p fc Es Ec " d-Kd ' Kd Ec Es fc fc d-Kd ~ Kd -K K NOTES ON POWER PLANT DESIGN IOC as the total tension equals the total compression f,Pbd=y2fcbdK; P=V2K but j^ = n ^-^- u — n K K P=V2K K^ + 2 Pn K + {PnY = 2 Pn + {Pn)'' K + Pn= V2Pn + {PnY Es from which K may be found as soon as the steel ratio is known and the ratio of -^ j d= d - HKd If K = 0.375 j =1 - VsK j = 0.872 or about % A value of j = .85 is used by some designers on both cinder and stone concrete of 1 -2-4 mixture Ms=Tjd = fsAjd = fsPjbd^ Mo=Cjd=y2fcbKdjd=y2foKjbd' The fibre stress in the steel for a given bending moment is equal to /. M M Ajd Pjbd^ The fibre stress in the concrete /c = ^j^-j^ equating values of M; 2M_ Kjbd^ fc = 2fsP K bd^ 2M fcKj ' bd^ = M fsPj 110 NOTES ON POWER PLANT DESIGN W l^ The bending moment for beams and for slabs contmuous over the supports is M = — -— , where W is the load per inch of length and / is the length in inches. If continuous over one support only W l^ W P M = - - ;" while if freely supported M = — — If a rectangular slab be reinforced in two directions the bending moment would, for a square W l^ panel where one-half the load would be carried in each direction, be ikf = , where W is the total load per square inch. For a rectangular panel the proportion of the load carried by the reinforcement placed the short way of the span is r = -^ — p rW P The reinforcement for the short span is then figured taking as the bending moment and in a similar way the reinforcement for the long span by using a value of ikf = 10 {\-r)W P 10 The distance from the center of the reinforcing bars to the bottom of the floor slab should be 1"; the distance between centers of adjacent bars at least 23/^ diameters. The distance from the side of a beam or slab to the center of the outer bar should be about 2 diameters of bar. The bearing pressure per square inch where a slab rests on its supports is not to exceed 650 lbs. per sq. inch. Concrete beams sometimes fail through diagonal tension; floor slabs seldom fail in this way. A beam or slab may be made safe against such failure by keeping the average shear on a concrete having a compressive strength at 28 days of 2000 lbs., under 40 lbs. per sq. in. in cases where the horizontal reinforcing steel is not bent so as to offer help in resisting diagonal tension: where the reinforcing material is bent so that it does offer help the average shear may be taken as 60 lbs. per sq. in.; where ample reinforcement for resisting diagonal tension is specially provided, the average shear in the concrete may be taken as 120 lbs. per sq. in. As the horizontal and the vertical shear are of the same intensity, the unit shear may be , Vertical shear on Section expressed as = r-^ j may be taken as .85 or .87. In finding the area of reinforcing steel (As) necessary for width 6 if it be assumed that the concrete resist one third of the total shear (F) on this width, and the steel the remaining two- thirds, then for vertical stirrups spaced a distance (*S) apart longitudinally A - ^^^ If the reinforcing material makes an angle of 45" "then the area of the steel becomes .7 of this value. If the safe bonding strength of steel rods be taken as 80 lbs. per sq. inch of rod surface, and as 40 lbs. per sq. inch of wire surface then calling (o) the entire surface per inch of length of rods in V a section Cb) the bond stress per unit of surface of the bars = . , which must be less than 80 for ■ jdo rods and less than 40 for wire. NOTES ON POWER PLANT DESIGN 111 Example : A continuous slab 8'-4" span is to carry a total load of 288 lbs. per sq. ft. — the slab to be of 1-2-4 stone concrete. Required depth of slab and area of reinforcement. /c = 650 lbs. sq. inch. fs = 16,000 lbs. sq. inch. n= 15 288 X 100 X 100 = 20,000 r ui SI iiiy L /J WlUC IV. L — 12 X 12 bd^ = 40,000 188 650 X .375 X .872 P = 20,000 = .762% 188 X 16,000 X .872 d' = 188 = 15.66 d = 3.96" 12 use 5" slab. Steel 4 X 12 X .00762 = .366 sq. ins. per ft. width use 5^" rods spaced 3" on centres. 1200 The unit shear = The bond stress 12 X .87 X 4 1200 29 lbs. .87 X 4 X (4 X .375 x tt) = 74 lbs. Some types of concrete floors are shown by illustrations taken from the Catalogue of the Clinton Wire Cloth Co., Clinton, Mass. The wire cloth consists of a wire mesh made up of a series of parallel longitudinal wires spaced certain distances apart and held at intervals by means of transverse wires arranged at right angles to the longitudinal ones and electrically welded to them at the points of intersection. A regulation governing the use of any type of reinforcement for concrete floors in New York City requires that the system be subjected to a load test. The test is made upon a sample floor approximating as nearly as possible the conditions of actual construction, and the particular span, slab and reinforcement as tested are approved by the Bureau of Buildings for one-tenth of the load which the test specimen actually carries. The following floor slabs have thus been tested in New York City and approved by the Bureau of Buildings for the various live loads as given: The dias, of wire correspondmg to W. & M. gages: dia. area No. 3 .331 .086 No. 4 • .307 .074 No. 5 .283 .063 No. 6 .263 .054 dia. area No. 7 .244 .047 No. 8 .225 .040 No. 9 .207 .034 No. 10 .192 .029 In this type of reinforcement the wire is placed %" above the bottom of the slab on all slabs from 3" to through 43^" in thickness; 1" above on thicknesses of 5", 6" and 7"; and 134" above on slabs 8" thick. Another reinforcing material known as "steelcrete" made by the Eastern Expanded Metal Co. of Boston is shown by the illustration which appears on page 114. 112 NOTES ON POWER PLANT DESIGN •^- ■ -.V ■ U« ■ -i •* 4 "^A'U /£' Afesfy *7-^/0 C///7/-0/? M/^e<^ Mre C///)fo/7 JY^/(^ec/ )y/'re 7'-6' Approved L.ive Load 200 Pounds Per Square Foot r-^ l-Z'S C/nc/er Ca/?crefe ----- ■■ "u 'J >■■' ■ -I ■ ^^'x/2'Me5/? *J~9 C///?fa/7 Jrl'/a'^i/ Mre Approved Live Load 250 Pounds Per Square Foot Z"x8"Me5/7 *3'd C//nf£>/7 )fe/ded hire Approved Live Load 150 Pounds Per Square Foot /■ 1-2-^ C//?der Concrete ^d'x /a" Afes/? ^S-/0 C//nton }fe/<:/ec/ JiT/re 6'-D" \ V Approved Live Load 150 Pounds Per Square Foot ^ /-E-ff 0/7der Ca/?cre/s :r^J t: a^ " ■■ ' '-' ■ "^"' -" -■^'x/tMes/? *J-*3 Cf/ntan Jfe/ded M're ^t-C//>7Ap/7 M/dec/ Mrt^ 6'-6 " Approved Live Load 300 Pounds Per Square Foot rfi 1-2-S C/nder Co/?crefe •3'xl2" MesA *4^9 C///?fo/J /fe/dea^ Mre (J-6' C/into/? //e/ded J//re Approved Live Load 400 Pounds Per Square Foot NOTES ON POWER PLANT DESIGN 113 This cut also gives some idea of the method by which the mesh is manufactured. "Steelcrete" can be obtained in lengths up to 144" and in lengths less than 144" varying by- some multiple of 8". The size of the diamond, weight of reinforcement per sq.ft., etc., are given in the following table which has been taken from the maker's catalogue. DECIMAL STANDARDS FOR "STEELCRETE" EXPANDED METAL Width of Length of Section in Wt. per Number Size of Standard Number of Wt. per Diamond Diamond sq. in. per square foot of Sheets Sheets sq. ft. in bundle in ft. of width in lbs. in a bundle a bundle lbs. Designation of Size of Mesh Mesh 3-13-075 3" 8" .075 .27 10 1 r6'0"x 8'0" 1 6'0" x 12'0" 480 720 129.6* 194.4 3-13-10 3" 8" .10 .37 7 1 r6'9"x S'O" 1 6'9" X 12'0" 378 567 ' 139.9 209. S 3-13-125 3" 8" .125 .46 7 1 r5'3"x 8'0" [ 5'3" X 12'0" 294 441 135.2 202.9 3-9-15 3" 8" .15 .55 5 , r7'0"x 8'0" 1 7'0" X 12'0" 280 420 154.0 231.0 3-9-20 3" 8" .20 .73 5 ^ f5'3"x 8'0" 1 5'3" X 12'0" 210 315 153.3 230.0 3-9-25 3" 8" .25 .92 5 ' r4'0"x 8'0" 1 4'0" X 12'0" 160 240 147.2 220. S 3-9-30 3" 8" .30 1.10 .2 1 r7'0"x S'O" 1 7'0" x 12'0" 112 168 123.2 184.8 3-9-35 3" 8" .35 1.28 2 1 r6'0"x S'O" 1 6'0" X 12'0" 96 144 122.9 1S4.3 3-6-40 3" 8" .40 1.46 2 1 r7'0"x S'O" 7'0" X 12'0" 112 168 163.5 245.3 3-6^5 3" 8" .45 1.65 2 1 ^6'3"x S'O" 6'3" X 12'0" 100 150 165.0 247.5 3-6-50 3" 8" .50 1.83 2 1 '5'9"x S'O" 5'9" X 12'0" 92 138 168.4 252.5 3-6-55 3" 8" .55 2.01 2 1 ^5'3"x S'O" 5'3" X 12'0" 84 126 168.8 253.3 3-6-60 3" 8" .60 2.19 2 1 '4'9"x S'O" 4'9" X 12'0" 76 114 166,4 249.7 3-6-75 3" 8" .75 2.74 2 1 '3'9"x S'O" 3'9" X 12'0" 60 90 164.4 246.6 3-6-100 3" 8" 1.00 3.66 2 1 '2'9"x S'O" . 2'9" X 12'0" 44 66 161.0 241.6 "STEELCRETE" SPECLA.L MESHE S ^-13-25 .95" 2" .225 .80 5 6'0" X S'O" 240 192.0 13^-13-20 1.36" 3" .181 .73 5 4'0" X S'O" 240 116.8 2-13-15 1.82" 4" .15 .50 5 S'O" X S'O" 200 100.0 114 NOTES ON POWER PLANT DESIGN "St€®!cirone/ea''Afe'/a/. 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' &/>aa 7 /£ZZ /ZU /a/3 SZ6 d83 ^73 4SS 4/3 333 Z66 Z03 /36 /z/ 93 7/ 33 39 Z7 " 9. a/) a e Z/2S /66S /334 /aS9 F03 7S9 ^413 ss/ 473- 339 Z76 2/3^ /6S 732 /as 3a 6/ 43- 3Z 'f /a^a/> 7 Zi^ Z/03 /6S^ /379 //^'f 963 ff/9 7az ^a6 4^6/ 337 Z3a zzz 776 /4o /// 37 67 •3/ >. 76>.9aa /a 3?ff4 ZS7^ Z0^9 /i9S /407 //^ /if/>S SU 7^^ ^7Z 4413 33/ ZSo ZZ4 73a 74^ //3- 9/ 7/ '. //, 7aa // 3'93s\3o8£ Z4S0 2C3Z /^9a /4ZS /Z/3 /a44 9/>.s 693 34/ 4Z9 3'^4 277 Z2S /8Z 747 7/9 94 - /z:3aa /Z" 'fiZ0\3iZS\z9/£ Z3a7 /9S7 /677 /4sa /Z3/ 7/>6S SZO 64Z ^// 4// 333 Z7/ ZZZ 73/ 747 //f /3.3aa 122 NOTES ON POWER PLANT DESIGN Adjoining sheets should be lapped 8" on the end and one and one-half inches on the side. They should be wired together every three feet on the ends and every four feet on the sides. A reinforcing fabric known as the Triangle Mesh Concrete Reinforcement is manufactured by the American Steel and Wire Co. The tables which follow have been copied from an Engineer's Handbook published by the Company. This triangle mesh steel woven wire is made with both single and stranded longitudinal, or tension members. That with the single wire longitudinal is made with one wire varying in size from a No. 12 gauge up to and including a K" dia., and that with the standard longitudinal is composed of two or three wires varying from No. 12 gauge up to and including No. 4 wires stranded or twisted together. These longitudinals either stranded or solid are invariably spaced 4" centres, the sizes being varied in order to obtain the desird cross-sectional area of steel per foot of width. (See illustration.) Area ol S2i 4 I li2Ki5. oareinUy traded JiA •So II o2 1 " MOMENTS OF RESISTANCE IN FOOT POUNDS PER FO'OT OF WIDTH Iss CROSS SECTIONAL AREA IN SQUARE INCHES OF STEEL REINFORCEMENT PER FOOT OF WIDTH |i- .04 .06 .08 .10 .12 .14 .16 .18 .20 ■25 .30 .3a .40 .45 .50 .55 .60 .65 .70 .75 .80. .90 1.00 3 % K X 1 1 1 1 1 m IK 30 36 42- 48 54 60 66 72 78 84 90 96 102 108 114 120 86 114 137 160 192 130 165 203 237 275 313 337 168 222 268 329 377 407 455 489 ■547 210 271 332 4D4 458 498 572 634 678 756 764 248 327 395 478 557 589 659 742 811 913 934 1023 1104 289 375 458 552 636 679 774 849 941 1017 1103 1156 1257 1346 1437 325 423 520 625 734 769 888 991 1071 1172 1216 1S52 1409 1508 1623 1728 341 353 377 578 611 858 1136 900 1194 1519 1246 1585 1764 1644 18a5 2232 1893 2314 2756 2381 2848 3334 3872 2922 3431 3968 42.'i5 3525 4072 4371 4963 4169 4464 5080 5725 6077 4259 4566 5207 5860 6200 6914 5309 5987 6340 7055 7836 5498 6201 6576 7338 8114 478 592 697 812 858 973 1095 1199 1326 1383 1483 1636 1670 1807 1936 525 653 769 890 968 1086 1201 1327 1478 1548 1678 1786 1831 1992 2144 3>^ 4 804 954 1100 1187 1337 1513 1664 1831 1877 2062 2232 2309 2447 2660 i}4 5 6 7 g 1327 1403 1612 1787 1957 2179 2257 2443 2673 2703 2897 3068 1637 1857 2058 2286 2524 2632 2820 3037 3172 3343 a573 2099 2359 2612 2866 2951 3257 3470 3560 3874 4075 2625 2895 3157 3320 3627 3900 4021 4313 4572 3216 3541 3686 3995 4256 4479 4749 5066 3998 4360 4679 4857 5182 5557 4723 5100 5308 5612 6044 5668 8>i g 5518 6125 6529 6410 6788 10 6550 7571 701l| 7395 8393 Maiimnm Strcaaeai Steel = = 16.000 pound a, Coiaorete = 700 ponnda Cone. Ii2i4 is u oS MOMENTS OF RESISTANCE IN FOOT POUNJuS PER FOOT OF WIDTH lU CROSS SECTIONAL AREA IN SQUARE INCHES OF STEEL REINFORCEMENT PER FOOT OF WIDTH w .04 .06 .08 .10 .12 .14 .16 .18 .20 .25 .30 a5 .40 .45 .50 .55 .60 .65 .70 .75 .80 .90 1.00 2V< X % X X IK IK 30 36 42 48 54 60 66 73 78 84 90 96 102 108 U4 120 86 114 137 160 192 130 165 2oa 237 275 313 337 168 222 268 329 377 407 455 489 547 210 271 332 404 458 498 572 634 678 756 764 248 327 395 478 557 589 659 742 811 913 934 1023 1104 289 375 458 552 636 679 774 849 941 1017 1103 1156 1257 1346 1437 325 423 520 625 734 769 888 991 1071 1172 1216 ia52 1409 1508 1623 1728 366 478 592 697 812 858 973 1095 1199 1326 1383 1483 1636 1670 1807 1936 379 406 623 658 924 969 1286 1342 1707 1770 1976 2038 2492 2.565 3066 3147 3698 3796 4386 4704 4490 4802 4586 4913 5607 5717 6447 6828 5920 6678 7081 7902 8739 3 525 653 769 890 968 1086 1201 1327 1478 1548 1678 1786 1831 1992 2144 3V< 804 954 1100 1187 1337 1513 1664 1831 1877 2062 2232 2309 2447 2660 4 1137 1327 1403 1612 1787 1957 2179 2257 2443 2673 2703 2897 3068 i% 1532 1637 1857 2058 2286 2524 2632 2820 3037 3172 3343 $573 5 1849 2098 2359 2612 2866 2951 3257 3470 3560 3874 4075 s^ 2340 2625 2895 3157 3320 3627 3900 4021 4313 4572 6 2889 3216 3541 3686 3995 4256 4479 4749 5066 6^4 3495 3875 3998 4360 4679 4857 5182 5557 7 7^ 416C 435S 4723 51O0 5308 5612 6044 8 5084 5519 5683 6125 6529 5444 5866 6129 6550 7011 6104 9 6280 6500 6973 7395 6903 7310 9^ 10 7395 7968 8154 9038 Moxunnm Streaaeat Sleel = = IS.OOO ponnda. Cotterete = 70U ponnd Cone. l>2i4 Mx, II •So |s u 2 'if MOMENTS OF RESISTANCE IN toOt POUNDS PER FOOT OF WIDTH S|| CROSS SECTIONAL AREA IN SQUARE INCHES OF STEEL REINFORCEMENT PER FOOT OF WIDTH .04 .06 .08. .10 .15 .14 .16 .18 .20 .25 .30 .35 v40 .45 .50 .55 .60 .65 .70. .75 .80 .90 1.00 2K X X X X 1 1 1 1 1 IX ■ IK. IK IK 30 36 42 ■48 54 60 66 7? 78 84 90 96 102 108 114 120 97 128 154 J8C 216 146 185 228 267 309 362 379 189 250 301 370 424 456 512 550 616 237 305 373 454 515 ,560 644 714 765 851 859 276 368 444 538 627 663 741 835 ' 913 1027 .1050 1152 1243 325 515 621 716 764 871 956 1059 1144 1240 laoo 1414 1514 1618 353 -367 379 579 406 623 872 658 924 1223 968 1286 1636 1821 1342 1707 1899 2316 1770 1976 2404 2871 2038 2492 2968 3489 2560 3066 4442 3147 3898 4274 4579 6210 3796 4386 4704 e34S 6035 6373 4490 4802 6166 6544 7284 4586 4913 5607 6311 6677 7446 8224 5717 6447 6828 7597 8440 5920 6678 7081 7902 8739 3 476 585 703 g26 865 yyy 1115 1206 1318 1366 1522 1586 1697 1827 1944 .537 666 784 914 965 1095 1234 1349 1491 1554 1668 1840 1879 2034 2180 3K 734 865 1001 1O90 1352 1493 16^ 1741 1887 2009 2059 2240 2413 4 1074 1238 1336 1702 1872 2059 2110 .2320 2511 K98 2753 2993 4K 5 1493 1578 1814 2010 2200 2452 2537 2749 3006 3041 3259 3451 5K 2089 2315 2573 2840 2958 3173 3416 3569 3761 4O20 6 2654 2938 3225 3318 3664 3906 4004 4358 4584 6J^ 3257 3551 3T35 4081 4386 4524 4852 5144 7 3984 4143 4494 4789 5700 8 4905 6264 5464 5830 6252 6104 8K 9 5738 5972 6313 6810 6903 7310 9K 6890 7345 8154 10 7889 9038 124 NOTES ON POWER PLANT DESIGN LONGITUDINALS SPACED 4-INCH CENTERS CROSS WIRES SPACED 4- INCH CENTERS Number and Gauge of Wires, Areas Per Foot Width and Weights Per 100 Square Feet Styles Marked * Usually Carried in Stock. Style No. of Wires Gauge of Wire Gauge of Sectional Area Sectional Area Cross Sectional Approximate Number Each Long Each Long Cross Wires Long. Sq. In. Cross Wires Area per Ft. Width Weight per 100 Sq. Ft. *4 6 14 .087 .025 .102 43 5 8 14 .062 .025 .077 34 6 10 14 .043 .025 .058 27 *7 12 14 .026 .025 .041 21 *23 K" 12>^ .147 .038 .170 72 24 4 12J^ .119 .038 .142 62 25 5 12>^ .101 .038 .124 55 *26 6 nyi .087 .038 .110 50 *27 8 12K .062 .038 .085 41 28 10 12>^ .043 .038 .066 34 29 12 12K .026 .038 .049 28 31 2 4 12K .238 .038 .261 106 32 2 5 12K .202 .038 .225 92 33 2 6 12K .174 .038 .196 82 34 2 8 12>^ .124 .038 .146 63 35 2 10 123^ .086 .038 .109 50 36 2 12 12K .052 .038 .075 37 *38 3 4 12>^ .358 .038 . .380 151 39 3 5 12K .303 .038 .325 130 40 3 6 12K .260 .038 .283 114 41 3 8 12K .185 .038 .208 87 *42 3 10 12K .129 .038 .151 66 43 3 12 liyi ' .078 .038 .101 47 LENGTH OF ROLLS: 150-ft., 300-ft. and 600-ft. WIDTHS: 18-in., 22-in., 26-in., 30-in., 34-in., 38-in., 42-in., 46-in., 50in., 54-in. and 58-in. LONGITUDINAL SPACED 4-INCH CENTERS CROSS WIRES SPACED 2-INCH CENTERS Number and Gauge of Wires, Areas Per Foot Width and Weights Per 100 Square Feet Styles Marked * Usually Carried in Stock Style No. of Wires Gauge of Wire Gauge of Cross Sectional Area Sectional Area Cross Sectional Approximate ^lunber Each Long Each Long Wires Long. Sq. In. Cross Wires Sq. In. Area per Ft. Width Weight per 100 Sq. Ft. 4-A 6 14 .087 .050 .102 53 5-A 8 14 .062 .050 .077 44 6-A 10 14 .043 .050 .058 37 * 7-A 12 14 .026 .050 .041 31 23-A K" 12K .147 .076 .170 86 24-A 4 12K .119 .076 .142 76 25-A 5 \2y^ .101 .076 .124 70 26-A 6 viyi .087 .076 .110 64 27-A 8 i2y2 .062 .076 .085 55 *28-A 10 12K .043 .076 .066 48 29-A 12 12K .026 .076 .049 42 31-A 2 4 12K .238 .076 .261 120 32-A 2 5 i2y2 .202 .076 .225 107 33-A 2 6 12K .174 .076 .196 97 34-A 2 8 12K ,124 .076 .146 78 35-A 2 10 12K .086 .076 .109 64 36-A 2 12 12>^ .052 .076 .075 52 38-A 3 4 12^ .358 .076 .380 165 39A 3 5 viy .303 .076 .325 145 40-A 3 6 12K .260 .076 .283 129 41-A 3 8 i2y2 .185 .076 .208 101 42-A 3 10 12K .129 .076 .151 81 43-A 3 12 12K .078 .076 .101 62 LENGTH OF ROLLS: 150-ft., 300-ft. and 600-ft. WIDTHS: 18-in., 22-)n., 26- in., 30-in., 34-in.. 38-in., 42-in., 46-in., 50-in., 54-in. and 58-in. NOTES ON POWER PLANT DESIGN 125 This table taken from the Engineer's Handbook gotten out by the American Steel and Wire Co. contains information which may be of use. Mixtures Required for 1 cub ic yard ram med concrete Stone Stone Gravel 1 in. and under. 2* in and under. dust screened out dust screened out J in. and under " i2' . m- m -o ^ ■S -o -0 T3 , '^ >. >> ,. m >> >> •A ^ ^ a c3 3 .3 ^^ 3' .3' C-5 3 -TfS S a a o g a o g - 0) c r T V a c3 ^ S C3 -S 0) a a V a t-t O ra M O m m O w m w 1 1.0 2.0 2.57 0.39 0.78 2.63 0.40 0.80 2.30 0.35 0.74 1 1.0 2.5 2.29 0.35 0.70 2.34 0.36 0.89 2.10 0.32 0.80 1 1.0 3.0 2.06 0.31 0.94 2.10 0..32 0.96 1.89 0.29 0.86 1 1.0 3.5 1.84 0.28 0.98 1.88 0.29 1.00 1.71 0.26 0.91 1 1.5 2.5 2.05 0.47 0.78 2.09 0.48 0.80 1.83 0.42 0.73 1 1.5 3.0 1.85 0.42 0.84 1.90 0.43 0.87 1.71 0.39 0.78 1 1.5 3.5 1.72 0.39 0.91 1.74 0.40 0.93 1.57 0.36 0.83 1 1.5 4.0 1.57 0.36 0.96 1.61 0.37 0.98 1.46 0.33 0.88 1 1.5 4.5 1.43 0.33 0.98 1.46 0.33 1.00 1.34 0.31 0.91 1 2.0 3.0 1.70 0.52 0.77 1.73 0.53 0.79 1.54 0.47 0.73 1 2.0 3.5 1.57 0.48 0.83 1.61 0.49 0.85 1.44 0.44 0.77 1 2.0 4.0 1.46 0.44 0.89 1.48 0.45 0.90 1.34 0.41 0.81 1 2.0 4.5 1.36 0.42 0.93 1.38 0.42 0.95 1.26 0.38 0.86 1 2.0 5.0 1.27 0.39 0.97 1.29 0.39 0.98 1.17 0.36 0.89 1 2.5 3.5 1.45 0.55 0.77 1.48 0.56 0.79 1.32 0.50 0.70 1 2.5 4.0 1.35 0.52 0.82 1.38 0.53 0.84 1.24 0.47 0.75 1 2.5 4.5 1.27 0.48 0.87 1.29 0.49 0.88 1.16 0.44 0.80 1 2.5 5.0 1.19 0.46 0.91 1.21 0.46 0.92 1.10 0.42 0.83 1 2.5 5.5 1.13 0.43 0.94 1.15 0.44 0.96 1.03 0.39 0.86 1 2.5 6.0 1.07 0.41 0.97 1.07 0.41 0.98 0.98 0.37 0.89 I 3.0 4.0 1.26 0.58 0.77 1.28 0.58 0.78 1.15 0.52 0.72 1 3.0 4.5 1.18 .0.54 0.81 1.20 0.55 0.82 1.09 0.50 0.75 1 3.0 5.0 1.11 0.51 0.85 1.14 0.52 0.87 1.03 0.47 0.78 1 3.0 5.5 1.06 0.48 0.89 1.07 0.49 0.90 0.97 0.44 0.81 1 3.0 6.0 1.01 0.46 0.92 1.02 0.47 0.93 0.92 0.42 0.84 1 3.0 6.5 0.96 0.44 0.95 0.98 0.44 0.96 0.88 0.40 0.87 1 3.0 7.0 0.91 0.42 0.97 0.92 0.42 0.98 0.84 0.38 0.89 1 3.5 5.0 1.05 0.56 0.80 1.07 0.57 0.82 0.96 0.50 0.76 1 3.5 5.5 1.00 0.53 0.84 1.02 0.54 0.85 0.92 0.48 0.78 1 3.5 6.0 0.95 0.50 0.87 0.97 0.51 0.89 0.88 0.46 0.80 1 3.5 6.5 0.92 0.49 0.91 0.93 0.49 0.92 0.83 0.44 0.82- .1 3.5 7.0 0.87 0.47 0.93 0.89 0.47 0.95 0.80 0.43 0.85 1 3.5 7.5 0.84 0.45 0.96 0.86 0.45 0.-98 0.76 0.41 0.87 1 3.5 8.0 0.80 0.42 0.97 0.82 0.43 1.01 0.73 0.39 0.89 1 4,0 6.0 0.90 0.55 0.82 0.92 0.56 0.84 0.83 0.51 0.77 1 4.0 6.5 0.87 0.53 0.85 0.88 0.53 0.87 0.80 0.49 0.79 1 4.0 7.0 0.83 0.51 0.89 0.84 0.51 0.90 0.77 0.47 0.81 1 4.0 7.5 0.80 0.49 0.91 0.81 0.50 0-.93 0.73 0.44 0.83 1 4.0 8.0 0.77 0.47 0.93 0.78 0.48 0.95 0.71 0.43 0.86 1 4.0 8.5 0.74 0.45 0.95 0.76 0.46 0.98 0.68 0.42 0.88 1 4.0 9.0 0.71 0.43 0.97 0.73 0.44 1.01 0.65 0.40 0.89 I bbl. cement & 2 bbl. sand will cover 99 sq. ft. of floor i in. thick. I ' " J « << << .■< 68 .. « .< a J << << 126 NOTES ON POWER PLANT DESIGN COSTS To give an idea as to the relative costs of the different items entering into the total cost of a Power House two tables have been given. It is seen from these tabulations that the total cost per K. W. exclusive of the land is around $105 for a station of moderate size and goes as low as $60 for large stations. In one station the cost of piping may be greater than that in another of the same size. This may be offset, however, by the lower cost of some other item so that the total cost of the two does not differ much. and discharge and buildings $3.50 15.00 3.50 POWER HOUSE COST PER RATED K. W. INSTALLED Max Foundations ...... Sidings, roadways, circulating water intake Chimneys and flues .... Building Total $22.50 Boilers, installed 14.00 Superheater . . . . . . . . . . . . 1.50 Stokers 10.00 Economizers . . . . . . . . . . . . 5.00 Coal Conveyor and bunkers . . . . . . . . . 6.00 Ash conveyor . . . , . . . . . . . 1 . 50 Piping and pipe covering . . . . . . . . . 12 . 00 Feed pumps . . . . . . . . . . . . 1 . 00 Feed water heater • . . . . . . , . . . . 2 . 00 Turbine and generator . . . . . . . . . . 15 . 00 Condenser, jet type . . . . . . . . . . 3.00 Exciter 1,50 Switchboard 4.00 Cables and conduits in power house . . . . . . . . 6 . 00 Incidentals ............ 2.00 Machinery Total Grand Total Min. $1.50 8.00 2.50 $12.50 8.00 1.00 00 00 00 00 6.00 1.00 1.00 12.00 2.50 .75 2.50 3.00 2.00 ,50 106.50 60 ,75 25 Koester in Steam Electric Power Plants gives the following tabulations of costs for plants of 3000 to 5000 K.W. capacity. COST OF TURBINE PLANTS 3000 to 5000 K. W. — per K. W. Min. Max. Excavations and Foundations Building Tunnels . Flues and Stacks Boilers and Stokers . Superheaters Economizers . Coal and Ash System Blowers and Ducts . Pumps and Tanks . Piping complete Turbo-Generators . Condensers — surface Exciters . Cranes . Switchboard . Labor and Incidentals $2.00 10.00 1.75 2.50 8.50 2.00 2.00 1.50 1.00 1.00 2.25 22.00 5.00 .75 .25 2.00 1.00 $2.50 15.00 4.00 3.50 12.00 2.50 2.25 3.00 1.50 1.25 4.50 25.00 8.00 1.00 .50 3.50 2.00 $65.00 $92.00 NOTES ON POWER PLANT DESIGN 127 COST OF EXCAVATION FOR FOUNDATIONS Cost per cubic yard Poor Sand Pile onf or wet clay Good" Good" Good* dry crib or Ledge Gravel Sand Clay Work Sand 1st 5 ft. 2.00 0.40 0.30 0.25 0.50 0.60 2nd. 5 ft. 2.75 0.60 0.50 0.35 0.70 0.75 3rd. 5 ft. 3.50 0.80 0.70 0.80 1.00 1.50 ° Some bracing of banks required. * No bracing of banks required (large quantities excavated), t Average for 15 feet depth without sheet piling $0.90. Average for 15 feet depth with sheet piling $1.00. Rock excavation $2.00 to $3.00 per cu. yd. Cement costs from $1.30 to $1.50 per bbl. Sand costs $1.00 per cu. yd. delivered. Stone costs $1.00 per cu. yd. at crusher. Concrete footings concrete alone costs $7.20 per cu. yd. Forms cost about 12 cents a sq. ft. A rough estimate of the cost of a footing including excavation, concrete and forms may be made by figuring the concrete at $9.00 per cubic yard. PILES Oak piles 20-30 ft. long 12" butt 6" top, 17 cents per ft. of length. Oak piles 40-60 ft. long, 21 to 25 cents per ft. of length. Spruce piles 20-30 ft. long 10" butt, 15 cents per ft. of length. Cost of driving and cutting off, 9 cents per ft. of length. Concrete piles in place from $1.25 to $1.50 per ft. of length. BRICKS Bricks per 1000, $7.50 to $10.00. Cost of laying 1000 bricks in a wall 10" to 12" thick including mason, helper and staging is $8 to $8.50. 1000 bricks laid make 2 cu. yds. masonry and cost $16 to $18. CONCRETE WALLS AND FLOORS Concrete forms for floors, 12 cts. per sq. ft. Concrete forms for walls (2 sides) 24 cents sq. ft. wall area. Concrete wall 6" thick including forms, costs, 40 cents per sq. ft. Concrete, $7.20 cu. yard. If there is no abnormal amount of reinforcement the cost of a floor may be figured by adding the cost of the form 12 cents per sq. ft. to the cost of the concrete per sq. ft. which is $.0222 x thick- ness of floor in inches. Where there is an abnormal amoimt of reinforcement the cost of the steel should be considered. STEEL FRAMEWORK The cost of structural steel work varies with the price of steel and fluctuates between $45 and $75 per ton erected. " In general $60 a ton is a safe figure to use. 128 NOTES ON POWER PLANT DESIGN FLUES, DAMPERS, ETC. Flues should be figured by the cost per pound. A flue {}4" thick) without difficult bends may be estimated at 10 cents per pound erected. A flue may cost as much as 15 cents a pound where there is difficulty in erecting it on account of lack of space. BOILERS A high pressure water tube boiler 400 to 800 H. P. per unit, $16.50 H. P. erected. Superheater for same, f 1.50 to $1.00 per H. P. ECONOMIZERS Economizers 110 to $12 per tube erected or about * .50 per Boiler Horse Power. Stokers cost from STOKERS to $10 per rated H. P. of boiler. CHIMNEYS The cost of Radial Brick Chimneys is approximately as given below. These costs being for the structure above the foundations. Height Top diams. in ft. Ft. 4 6 8 10 12 14 75 1400 2000 2700 3700 125 3500 4300 4700 5100 150 6200 7200 7800 8300 175 7000 8000 9000 9800 200 10500 11000 12500 250 16500 18300 22000 16 24300 The comparative total costs of a chimney 150 ft. tall 8 ft. diam. as given by Christie in "Chim- ney Design and Theory" are: Red brick .... Radial brick Steel, self supporting full lined Steel, self supporting half lined Steel, self supporting unlined Steel guyed .... $8500 $5820 COAL CONVEYOR For a station of 15000 K. W. capacity about 1000 K. W. about $4.00 per K. W. .15 per K.W.; for 5000 K.W. about $2.50; for COAL BUNKERS For parabolic form estimate steel if of suspended type, rods or straps as $100 per ton erected, if of steel plate $75 per ton erected. Add to this the cost of the concrete lining. If of girder type figure steel as $65 per ton and add cost of concrete. NOTES ON POWER PLANT DESIGN 129 TURBINES AND GENERATORS Price depends upon market conditions but generally around $13 K. W. Some quotations obtained in February, 1915, at a time when steel was low in price were as follows : Turbine and Genebator 2000 K. W. . G. E. Co. 2000 K. W. bleeder type 1000 K. W. . 2000 . Westinghouse 2000 bleeder . 1000 . A Le Blanc condenser for the 2000 K. W. cost .... 1000 K. W. cost .... A cooling tower for 3000 K. W. 26" vacuum $7,800 above foundation. $23,000 $24,000 $13,500 $18,500 $19,500 $13,000 $4250 COMPARISON OF COSTS OF DIFFERENT TYPES OF ENGINES* Steam Consumption Cost per H. P. Cylinders Speed Exhaust Lbs. per I. H. P. hr. Total non cond'g cond'g Engine erected Bldgs. Boilers Chimney cost Simple High speed Non-cond'g 33 — . $17.50 $15.20 $32.70 High speed Cond'g — 22 21.00 12.00 33.00 Low speed Non-cond'g 29 — 25.00 14.20 39.20 Low speed Cond'g — 20 27.00 11.50 38.50 Compound High speed Non-cond'g 26 — 21.00 13.10 34.60 High speed Cond'g — 20 24.50 11.40 35.90 Low speed Cond'g — 18 30.00 11.00 41.00 Triple Exp. High speed Non-cond'g 24 — 26.00 12.50 38.50 High speed Cond'g — 17 29.00 10.50 39.50 Low speed Cond'g — 16 37.50 10.30 47.80 ""From Mr. Chas. E. Emery. The following pages giving the Cost of Steam and Power Plant Equipment were taken from an Article by Professor A. A. Potter, M. I. T. 1903, in Power, December 30, 1913. 130 NOTES ON POWER PLANT DESIGN TABLE OF COSTS OF STEAM AND GAS POWER-PLANT EQUIPMENT Name of Apparatus Air compressora Boilers, steam Condensers Economizers Type Single cylinder, belt-driven Duplex, belt-driveri Compound, belt-driven Single cylinder, f-team-driven Duplex, steam-driven Compound, steam-driven Vertical, fire-tube Submerged tubes, 100 lb. per sq. in. or less Full length tubes; 100 lb. per sq. in. or less Horizontal, fire-tube cylindrical, multi- tubulai, 100 lb. per sq. in. or less Portable locomotive Vertical, water-tube, pressures over 125 lb. per sq. in. Horizontal, water-tube, pressures over 125 lb. per sq, in. Barometric (28-in. vacuum) Jet condensers Fans and blowers Feed-water heaters Generators, electric Motors, electric Capacity Up to 4000 cu. ft. per rnin. Up to 850 cu. ft. per min. Up to 550 cu. ft. per min. Up to 350 ou. ft. per min. Up to 600 cu. ft. per min. Up to 500 cu. ft. per min. Under 20 hp. 20 to 50 hp. Up to 50 hp. Up to 200 hp. Up to 100 hp. 100 hp. to 225 hp. Up to 100 hp. Surface condensers Number of tubes 32 to 10,000, heating sur- face per tube = 12 to 13 sq. ft. Engines, internal combustion Engines, steam Gas engines Gasoline engines, hit-and-miss governor Gasoline engines, throttling governor Oil engines Producer gas engines, American mfg. Simple, Throttling governor, slide valve, vertical Up to 70 hp. Throttling governor, slide valve, horizontal 100 to 500 hp. 100 to 600 hp. Up to 30,000 lb. of steam per hr. Up to 30,000 lb. of steam per hour; 28-in vacuum. 26-in. vacuum Up to 35,000 lb. of steam per hr.; 28-in. vacuum Up to 30,000 lb. of steam per hr. ; 26-in. vacuum Capacity in lb . of water per tube = 60 to 70 Economizer alone Economizer erected Up to 300 hp. Up to 100 hp. Up to 75 hp. Up to 400 hp. Up to 300 hp. Equation of Cost in Dollars 52 -t- 1.95 X cu. ft. 316 4- 1.675 X cu. ft. 3.1 X cu. ft. 231 -I- 2.32 X cu. ft. 460 + 2.55 X cu. ft. 71.25 -f 4.025 X cu. ft. 49.2 4- 6.66 X hp. 116.4 -I- 3..35 X hp. 51.5 + 3.62 X hp. 64 -f- 4.14 X hp. 5.8 X hp. - 20 211 -f- 3.35 X hp. 121 + 5.68 X hp. 912 -I- 6.28 X hp. 149 + 8.24 X hp. 1055 -1-0.112 X (lb. steam cond.) 1176 -I- 0.1138 X (lb. steam cond.) 116 -f- 0.0591 X (lb. steam cond.) 1630 -I- 0.2038 X (lb. steam cond.) 413 + 0.1015 X (lb. steam cond.) Upper limit in cost Lower limit in cost Simple, Flywheel governor, piston or balanced slide valve, horizontal Automatic cut-ofi, single valve, vertical Flywheel governor, Corliss non-releasing valve, horizontal Corliss governor and valves, horizontal Flywheel governor, multiple fiat valves Cross compound, Ball governor, single-valve, horizontal Ball governor, single-valve, vertical Flywheel governor, multiported valves, horizontal Shaft governor, Corliss non-releasing valves, horizontal Tandem compound. Flywheel governor and slide valves, hori- zontal Flywheel governor and slide valves, ver- tical Flywheel governor, Corliss non-releasing valves, horizontal Flywheel governor, multiple slide valves Sizes 70to 140 in. Open Closed Direct current (voltage 110-2.50), belted Direct-connected .Alternating-current, belted Direct-connected Direct-current, belted ; smzll sizes Variable speed Alternating current: Single-phase (110-220 volts) Belted ; polyphase induction Variable speed Up to 70 hp. Up to 200 hp. $8 to $10 per tube $12 to $15 per tube 33.6 X hp. - 115 141 + 24.8 X hp. 309 -t- 36.1 X hp. 63.8 X hp. - 316 400 -f 33.5 X kp. 63.5 -I- 17.5 X hp. 107 + 13.3 X hp. 80 -f- 5.81 X hp. Up to 500 hp. Up to 30 hp. 30 to 150 hp. Up to 600 hp. Up to 400 hp. 300 to 900 hp. Up to 400 hp. Up to 330 hp. Up to 200 hp. Up to 600 hp. Up to 600 hp. Up to 400 hp. Up to 140 hp. Up to 300 hp. Up to 500 hp. Up to 1500 boiler hp. 1500 to 3000 boiler hp. Up to 3000 boiler hp. Up to 7 kw. (1400 to 2300 r.p.m.) 10 kw. to 300 kw. (600 to 1400 r.p.m.) Up to 300 kw. (100 to 350 r.p.m.) 300 to 1000 kw. (moderate speed) Up to 300 kv.a. (600 to 1800 r.p.m.) Up to 300 kv.a. (200 to 300 r.p.m.) 250 to 2500 kv.a. (100 to 250 r.p.m.) Up to 1.5 hp. (1400 to 2500 r.p.m.) 1.5 to 30 hp. (1000 to 1800 r.p.m.) 30 to 100 hp.— Upper limit (500 to 800 r.p.m.) Lower limit— (800 to 1000 r.p.m.) Up to 10 hp. — Upper limit Lower hmit Up to 25 hp. (1200 to 1800 r.p.m.) Up to 130 hp. (1200 to 1800 r.p.m.) Up to 25 hp. 35 to 60 hp. 386 -I- 6.69 X hp. 164 + 9.53 X hp. 372.5 -I- 9.55 X hp. 1100 -I- 8.94 X hp. 1040 -I- 8.45 X hp. 730 -i- 9.1 X hp. 685 -I- 7.69 X hp. 735 -I- 8.0 X hp. 750 -I- 10.4 X hp. 1100 -1- 9.62 X hp. 2015 + 9.74 X hp. 559 -I- 8.83 X hp. 610 + 12.7 X hp. 1295 -I- 10.79 X hp. ' 1010 -I- 7.65 X hp. 6.25 X (size in inches) 114.5 + 0.3787 X hp. 326 -I- 0.237 X hp. 40 -I- 0.72 X hp. 21.1 + 28.5 X kw. 10 X (kw.) — 9 313.3 + 10.93 X kw. 12.08 X (kw.) - 383 81 -I- 9.723 X kv.a. 375 -I- 7.477 X kv.a. 2413 -I- 4.69 X kv.a. 18..53 -I- 42.37 X hp. 53.3 -t- 12.4 X hp. 191.7 -I- 10.94 X hp. 213 -I- 8.264 X hp. 64.1 4- ,36.786 X hp. 69.2 -I- 10.56 X hp. 25 -t- 11.75 X hp. 116 -I- 4.72 X hp. 60.7 -f- 7.15 X hp. 157.6 + 3.573 X hp. NOTES ON POWER PLANT DESIGN 131 TABLE OF COSTS OF STEAM AND GAS POWER-PLANT EQUIPMENT - Name of Apparatus Producers, gas Producer plants, gas Pumps Purification plants Stokers Superheaters Transformers Turbines, steam Type Suction Pressure Suction Boiler feed Single-cylinder, piston pattern Duplex, piston pattern Single-cylinder, out«ide-packed, plunger pattern Duplex, outside-packed plunger pattern Centrifugal Horizontal, low-pressure, single-stage Horizontal, high-pressure, single-stage Horizontal, high-pressure, multi-stage Vertical, low-pressure, single-stage Vertical, high-pressure, single-stage Vertical, high-pressure, multi-stage Geared power Single cylinder Single-acting, triplex Double-acting, triplex Rotary force pumps Wet vacuum pumps Water Chain-grate Front-feed Under-feed 200 to 750 boiler hp. Air-cooled Oil-cooled Water-cooled Reaction type : Turbine and generator Impulse type : Turbine alone Turbine and generator Capacity Up to 300 hp. Up to 300 hp. Up to 200 hp. Up to 6000 gal. per hr. 6000 to 27,000 gal. per hr. Up to 29,000 gal. per hr. Up to 24,000 gal. per hr. Up to 49;000 gal. per hr. Up to 14,000 gal. per rain. Up to 5000 gal. per min. 5000 to 20,000 gal. per min. Up to 2200 gal. per min. Up to 20,000 gal. per min. Up to 20.000 gal. per min. Up to 1100 gal. per min. Up to 20,000 gal. per hr. Up to 83,000 gal. per hr. Up to 89,000 gal. per hr. 1200 to 20,000 gal. per hr. Up to 13,000 gal. per hr. 13,000 to 50,000 gal. per hr. 1000 to 20,000 gal. per hr. 100 to 300 boiler hp. 300 to 500 boiler hp. 100 to 660 boiler hp. Up to 600 boiler hp. 100 deg. of superheat 200 deg. of superheat 300 deg. of superheat Sizes up to 3000 ky. a Sizes up to 30 kv.a. 25 cycles 60 cycles Sizes 30 to 100 kv.a. 25 cycles 60 cycles Sizes up to 1000 kv.a. 1000 to 3000 kv.a. 500 to 5000 kw. 5000 to 10,000 kw. Up to 50 hp. 50 to 400 hp. Up to 40 kw. 25 to 350 kw. 1000 to 10,000 kw. - Continued Equation of Cost in Dollars 252 + 14.2 X hp. 860 + 15.15 X hp. 570 + 46.5 X hp. 17.8 + 0.2586 X (gal. per hr.) 106.8 + 0.011045 X (gal. per hr.) 585 + 0.0115 X (gal. per hr.) 0.034 X (gal. per hr.) " 0.042125 X (gal. per hr.) 52 -I- 0.05525 X (gal. per min.) 61 -I- 0.0868 X (gal. per min.) 210 + 0.05R7 X (gal. per min.) 117-1- 0.233 X (gal. pei min.) 60 + 0.05575 X (gal. per min.) 50 -I- 0.0865 X (gal. per min.) 12,5.7 + 0.27 X (gal. per min.) 90 -f- 0.0316 X (gal. per hr.) 56 + 0.03867 X (gal. per hr.) 195 -I- 0.0148 X (gal. per hr.) 8 4-0.0117 X (gal. perhr.) 18 + 0.01435 X (gal. per hr.) 14 + 0.00863 X (gal. per hr.) 1000 -t-0.2 X (gal. perhr.) 86 -t-4.28 X(hp.)j 434 4-3.1 X(hp.) f 312 4-3.015 X (hp.) 379 4-2.785 X (hp.) 165 4- 2.578 X (hp.) 52 4-3 466 X (hp.) 40 4- 4.28 X (hp.) 439 4- 1.467 X kv.a. 52.9 4- 8.1 X kv.a. 26.2 4- 6.25 X kv.a. 157 4- 4.68 X kv.a. 119.5 4- 3.57 X kv.a. 181 4- 1725 X kv.a. 805 4- 1099 X kv.a. 3335 4- 13.33 X kw. 17,500 4- 10.5 X kw. 171.5 4- 10.7 X hp. 10.74 X hp. — 54 304.2 4- 36.78 X kw. 30.4 X kw. - 100 8106 4- 11.34 Xkw. 132 NOTES ON POWER PLANT DESIGN The "Load Factor" = LOAD FACTOR Yearly output in K. W. hrs. 8760 X rated capacity in K.W. or The Station Load Factor = Yearly output in H. P. hrs. 8760 X rated capacity in H.P. 8760 = 24 X 365. Yearly output K. W. hrs. Rated capacity in K. W. x hrs. plant ran It is evident that the higher the load factor the cheaper the cost per K. W. hr. or per H. P. hr. becomes, inasmuch as the fixed charges are the same whether the plant is running at half load, full load, full time, half time or idle. If a plant had to be run continuously it would be advisable to have at least one spare unit and due to the cost of this spare unit the fixed charge would be greater than for a plant which was idle at night and hence gave opportunity to make repairs, so that a spare unit was not necessary. COST OF OPERATION The cost of operation of a power plant may be divided into: A. Fixed charges. 1. Investment. B. Operating expenses. 2. Administration. A. Fixed Charges. — These include under (1) interest on the investment, generally taken as 5 per cent; taxes 1 to 1.5 per cent; insurance .5 per cent; depreciation, a varying amount depend- ing upon the life of the apparatus and maintenance or ordinary repairs, frequently taken as 2.5 per cent. The maintenance is sometimes charged against operating expense. Under (2) such items as salaries of officers, clerks, stenographers, etc. not connected with the operating end. Office rent and office supplies are included. B. Operating Expenses. — This includes coal, oil, water, supplies for boiler and turbine room and labor. The life of the different items making up the Equipment of a Power Plant may be taken from the following table: LIFE OF APPARATUS Belts Boilers, Fire Tubes .... Boilers, Water Tubes . ... Breeching Steel ..... Buildings; Brick, Concrete, Steel Concrete Coal Bunkers ..... Coal conveyors — rectangular, bucket Coal Conveyor; Belt .... Cranes ...... Chimneys, brick .... Chimneys, steel, self-supporting Chimneys, steel guyed Economizers ..... Years 7 15 25 10 50 14 8 10 25 50 20 10 20 NOTES ON POWER PLANT DESIGN 133 Engines: Corliss Engines: High speed . Feed pumps, turbine centrifugal Feed pumps, plunger Generators, D. C. . . Generators, A. C. Heaters, open type . Heaters, closed type Motors .... Motor generator sets Piping Steel Flues Stokers Switchboard Turbines Wiring 25 15 15 12 20 25 20 10 20 15 15 10 7 25 15 20 DEPRECIATION If the life of a piece of apparatus is known to be 20 years, that is to say, at the end of 20 years the apparatus is considered worthless and its value as junk is enough to pay for its removal, then each year a certain amount of money should be put by as a sinking fund so that at the end of the 20th year, this money shall have accumulated to a sum sufficient to replace the apparatus. Evidently if the money put away did not draw interest, 5 per cent of the original cost would be added to the sinking fund each year; if however, the money drew 43^ per cent interest, com- pounded annually, the amount to be laid by each year would be 3.19 per cent of the first cost of the apparatus as is found by reference to the "interest table" which follows: lOOR This table has been calculated by means of the formula X = q , ^\n _ ^ X = rate of depreciation expressed in per cent of first cost. R - rate of interest received, compounded annually ; expressed as a decimal. n = years of life of apparatus. S = first cost of apparatus. This formula may be deduced thus : X The amount of money laid by each year is -tkt^S There has accumulated then X at the end of the first year -jr^S X X at the end of the second year -txptS {1 + R) + -TKrrS at the end of the third year -^S (1 + Rf + -^S (1 + i?) + -^S at the end of the fourth year -^S (1 + R)^ + -~^S (1 + Rf + -~^S {1 + R) + -~-S 134 NOTES ON POWER PLANT DESIGN at the end of the nth year -^S (1 + RTK . . .-^S (1 + Rf + -^S {I + R) + -^S This summation should equal S. Equating and solving for X. X = 100 (1 + i?)-l + . . . (1 + i?)2 + (1 + i?) +1 X°- 1 The summation of a series Z"'^ . . . X^ + X + 1 = hence X = X - 1 100 (1 + i?) - 1 lOOi? (1 + i?)° - 1 (1 + RY - 1 RATE OF DEPRECIATION (Per Cent of First Cost) Rate of Interest, Per Cent. 3.5 4 4.5 5 5.5 5 18.83 18.65 18.46 18.28 18.10 17.91 17.73 17.40 17.04 6 15.46 15.26 15.08 14.89 14.70 14.52 14.33 13.97 13.63 7 13.05 12.85 12.66 12.46 12.28 12.09 11.91 11.15 11.20 8 11.24 11.05 10.85 10.66 10.47 10.28 10.10 9.74 9.40 9 9.84 9.64 9.45 9.26 9.07 8.88 8.70 8.34 8.00 10 8.72 8.52 8.33 8.14 7.95 7.76 7.58 7.23 6.90 11 7.80 7.61 7.41 7.22 7.04 6.85 6.68 6.33 6.00 12 7.04 6.85 6.65 6.46 6.28 6.10 5.92 5.60 5.27 13 6.40 6.20 6.01 5.83 5.64 5.47 5.29 4.96 4.65 14 5.85 5.65 5.46 5.28 5.10 4.93 4.75 4.49 4.13 15. 5.37 5.18 4.99 4.81 4.63 4.46 4.29 3.97 3.66 16 4.96 4.77 4.58 4.40 4.22 4.06 3.89 3.58 3.30 17 4.59 4.40 4.22 4.04 3.87 3.70 3.54 3.24 2.96 18 4.27 4.08 3.90 3.72 3.55 3.39 3.23 2.94 2.66 19 3.98 3.79 3.61 3.44 3.27 3.11 2.96 2.67 2.47 20 3.72 3.53 3.36 3.19 3.02 2.87 2.71 2.44 2.18 25 2.74 2.56 2.40 2.24 2.09 1.95 1.82 1.58 1.36 30 2.10 1.93 1.78 1.64 1.50- 1.38 1.26 1.06 0.88 35 1.65 1.50 1.36 1.23 1.10 0.99 0.89 0.72 0.58 40 1.32 1.18 1.05 0.93 0.83 0.73 0.64 0.50 0.38 45 1.07 0.94 0.82 0.72 0.62 0.54 0.47 0.35 0.26 50 0.88 0.76 0.65 0.56 0.42 0.40 0.34 0.25 0.17 Assumed useM life of apparatus at left of column. The continuous expense based upon the original cost of the plant is sometimes taken as 14 per cent per year divided as follows :• interest 5 per cent; depreciation 5 per cent, repairs 2^/^ per cent, insurance 3^ per cent and taxes 1 per cent. NOTES ON POWER PLANT DESIGN 135 OPERATING COSTS IN CENTS PER K. W. HOUR FOR CERTAIN CENTRAL STATIONS IN MASSACHUSETTS Coal .462 .710 .618 .690 .703 .565 .635 .880 .740 .650 .740 Wages .192 .262 .296 .347 .360 .320 .342 .538 .308 .285 .410 Oil, Waste, etc .008 .009 .012 .019 .027 .020 .017 .032 .015 .019 .025 Water .024 .008 .040 .055 .034 .045 .032 .012 .025 .003 .027 Station Repairs, Bldgs. .015 .020 .052 .021 .012 .023 .035 .012 .017 .063 .034 Steam Equipment Repairs .042 .020 .147 .059 .055 .072 .072 .037 .041 .073 .158 Electrical Equipment Repairs. , .056 .009 .045 .046 .055 .014 .014 .029 .072 .019 .011 Miscellaneous .023 .022 .000 .000 .000 .021 .033 .080 .024 .040 .000 Total .822 1.060 1.210 1.237 1.246 1.080 1.180 1.620 1.242 1.152 1.412 Coal per ton $ . . . , , 3.99 4.75 3.60 4.40 4.79 3.78 4.49 4.68 4.52 3.97 4.51 K. W. Hours Output 88.5 9.4 8.7 6.0 5.4 4.7 4.6 4.0 4.0 3.7 3.1 1,000,000 BOSTON ELEVATED RAILWAY COMPANY Year Rated capacity 38,470 Yearly load factor Cost of coal per K. W. hour, cents Labor plus labor on repairs per K. W. hour, cents Coal and all supplies per K. W. hour, cents .... Total per K. W. hour, cents Cost of coal per ton $ 1906 1908 1910 1912 38,470 50,425 51,163 61,350 43 37 41.5 36.4 .47 .56 .48 .41 .17 .21 .17 .17 .60 .86 .58 .52 .77 1.07 .75 .69 3.186 3.568 3.283 3.202 OPERATING COSTS, COSTS IN CENTS PER K. W. HOUR Tyfical British Electric Light and Power Plants — 1902 (From Engineering Record — March, 1904) K.W. Yearly Coal Oil, waste Wages Repairs Total installed load . factor per cent and Supplies 6380 20.93 .52 .10 .16 .26 1.04 8740 12.31 .56 .06 .34 .28 1.24 1340 17.84 .52 .06 .34 .38 1.30 10477 14.75 .68 .08 .18 .36 1.30 3700 18.87 .70 .12 .30 .20 1.32 850 28.44 .82 .06 .30 .22 1.40 21190 25.11 .74 .12 .30 .26 1.42 1600 15.82 .74 .08 .40 .30 1.52 5642 12.97 .92 .20 .32 .18 1.62 1920 13.31 .72 .12 .36 .46 1.66 610 14.54 .92 .20 .36 " .22 1.70 990 19.79 1.10 .08 .42 .18 1.78 TOTAL COST IN DOLLARS OF A H. P. FOR A YEAH ON 10 HOUR BASIS Size of Plant Maximum Cost Minimum Cost H.P. per H. P. per H. P. 2000 . 24 21 1500 . 26 21 1200 30 22 1000- . 33 24 800 . 38 26 600 . 46 28 500 60 31 400 . 57 33 300 . 65 38 200 . 77 45 100 96 60 50 . 110 80 25 . . 130 110 136 NOTES ON POWER PLANT DESIGN DISTRIBUTION OF OPERATING COSTS The operating cost per K. W. hour varies from less than one cent in the large plants to three and one-half cents in the small plants. Plants of from 2000 to 5000 K. W. capacity would operate (between one and one-half and one and one-tenth cents. The cost is distributed about as follows : Coal . Wages . Oil and waste, etc. Water . Station Repairs, Bldgs. Steam Equipment Repairs Electrical Equipment Repairs Per Cent 56.0 28.0 2.0 2.0 1.6 6.3 4.1 100.0 A certain station of 10,000 K. W. rated capacity cost $100 per K. W. This cost was divided as follows: Buildings $20, Machinery $80. Charging 14 per cent on machinery and 7.5 per cent on buildings gives for fixed charges, .075 X 200,000 = 15,000 .14 X 800,000 = 112,000 127,000 Suppose the yearly load factor is 18 per cent and that the total operatuig cost per K. W. hour, is 1.121 cents. The total output in K. W. hours for the year is 8760 X 10,000 X .18 = 15,768,000 $127000 - 15,768,000 gives the overhead charge per K. W. hour to be added to the operating cost. This figures as .804 cents. .804 + 1.12= 1.925 cents. It is evident that the higher the load factor the less the overhead to be added per K. W. to operating cost. COST OF STEAM POWER — (Small Units) Size of plant in H. P. Cost of plant per H. P. . Fixed charge, 14 per cent ....... Coal per H. P. hour, in pounds ...... Cost of coal at $5 per ton ....... Attendance, 3080 hours ........ Oil, waste and supplies ........ Cost 1 H. P. per annum, 10-hour basis $279.00 Cost of 1 H. P. per hour $0.0906 6 10 20 $250.00 $220.00 $200.00 $35.00 $30.80 $28.00 20 15 12 $154.00 75.00 15.00 $103.00 50.00 10.00 $82.50 30.00 6.00 $194.80 $0.0832 $146.50 $0.0475 NOTES ON POWER PLANT DESIGN 137 COST OF GASOLENE POWER — Small Units Engineering News, Aug. 15, 1907. Size of plant in H. P. Price of engine in place . Gasolene per B. H. P. per hour Cost per gallon Cost per 3,080 hours Attendance at $1 per day Interest, 5 per cent Depreciation, 5 per cent Repairs, 10 per cent Supplies, 20 per cent Insurance, 2 per cent Taxes, 1 per cent Power Cost 2 6 10 20 $150.00 $325.00 $500.00 $750.00 . . . Hgal. Mgal. 3^ gal. Hgal. $0.22 $0.20 $0.19 $0.18 $451.53 $924.00 $975.13 $1386.00 308.00 308.00 308.00 308.00 7.50 16.25 25.00 37.50 7.50 16.25 25.00 37.50 15.00 32.50 50.00 75.00 30.00 65.00 100.00 150.00 3.00 6.50 10.00 15.00 1.50 3.25 5.00 7.50 $825.03 $1371.75 $1498.13 $2016.50 To these figures should be added charges on space occupied as follows: Value of space occupied ..... $100.00 Interest, 5 per cent ...... Repairs, 2 per cent . . Insurance, 1 per cent ...... Taxes, 1 per cent ...... Total annual charge for space Total cost per annum .... Cost of 1 H. P. per annum, 10 hour basis Cost of 1 H. P. per hour $833.03 416.51 $0.1352 $150.00 $200.00 $1385.25 239.87 $0.0780 $1516.13 151.61 $0.0492 $300.00 $5.00 2.00 1.00 1.00 $7.50 3.00 1.50 1.50 $10.00 4.00 2.00 2.00 $15.00 6.00 3.00 3.00 $9.00 $13.50 $18.00 $27.00 $2043.30 102.17 $0.0331 COST OF GAS POWER — Small Units .50 per 1000 cubic feet of gas less 20 per cent, if paid in 10 days = $1.20 net, gas 760 B. T. U. Size of plant in H. P. Engine cost in place Gas per H. P. hour in cu. ft. Value of gas consumed, 3080 hours Attendance, $1 per day Interest, 5 per cent Depreciation, 5 per cent Repairs, 10 per cent Supplies, 20 per cent Insurance, 2 per cent Taxes, 1 per cent Power cost Annual charge for space Total cost per annum . Cost of 1 H. P. per aimum, 10 hour basis Cost of 1 H.P. per hour . . 2 6 10 20 $200.00 $375.00 $550.00 $1050.00 30 25 22 20 $221.76 $554.40 $843.12 $1478.00 308.00 308.00 308.00 308.00 10.00 18.75 27.50 52.50 10.00 18.75 27.50 52.50 30.00- 37.50 55.00 105.00 40.00 75.00 110.00 210.00 4.00 7.50 11.00 21.00 2.00 3.75 5.50 10.50 $615.76 9.00 $624.76 312.38 $0.1014 $1023.65 13.50 $1387.62 18.00 $1037.15 172.86 $0.0561 $1405.62 110.56 $0.0456 $2237.50 27.00 $2264.50 143.22 $0.0367 138 NOTES ON POWER PLANT DESIGN GUARANTEES It is customary to ask that contractors, when submitting a bid for prime movers or for power- driven machinery, give a guarantee as to the performance or efficiency of the equipment they pro- pose to furnish. This guarantee may in the case of a steam engine be based on povmds of steam per I. H. P. or per K. W. hour at rated load which should be specified, as should also the pressure and con- dition of the steam at the throttle and the temperature of the cold condensing water. The steam consumption at half load and at twenty-five per cent overload may also be given and included in the guarantee. The performance of large pumping engines is stated in figures representing the "duty" or foot pounds of water work done per 1,000,000 B. T. U. or per 1000 lbs. of steam of quality and pressure specified. The performance of centrifugal pumping units when motor driven is often given in overall mechanical efficiency of pump and motor when working at stated conditions as to head and capacity. In contracts containing a guarantee as to performance, provision is made for deducting from the first cost ot the apparatus a fixed amount for each fraction of a pound the engine or turbine exceeds the consumption mentioned in the guarantee; similarly in the case of a high duty pumping engine a deduction is made for each million duty under that guaranteed. It is not necessary that there be a "bonus" for a performance better than that guaranteed. The deduction made from the original price in case of a failure to meet the guarantee is in no way to be in the nature of a penalty. It must be that amount which the purchaser would lose in money and accrued interest during the life of the apparatus through the less efficient performance than that guaranteed. For example, a certain contractor guaranteed a steam consumption per I. H. P, hour on an engine and condenser and failed to meet his guarantee. The contract read that should the steam consumption per I. H. P. at full load, namely 2000 I. H. P., exceed 13.7 lbs. per I. H. P. hour a deduction is to be made from the original contract price at the rate of $4400 per 1/10 lb. that the actual performance exceeds the guaranteed steam consumption, provided the steam consumption does not exceed that guaranteed by as much as 3/10 of a pound. Should the steam consumption at full load exceed that guaranteed by 3/10 of a pound or more, the purchaser could at his option reject the engine. The figure $4400 was arrived at in this way : The life of the engine may be taken as 18 years and it may be assiuned to run 3000 hours per year with full load in this case. The extra steam per hour per 1/10 lb. in excess of guarantee is per year .1 x 2000 x 3000 = 600,000 lbs. for engine alone. Adding 10% of this as the extra steam used by the auxiliaries makes 660,000 lbs. Assuming 9.5 lbs. actual evaporation per lb. of coal makes the extra coal per year 69,474 lbs. or 34.74 tons. With coal at $4.50 per ton this figures $156.33. If money draws 5 per cent interest, the loss at the end of 18 years may be figured as follows: End of first year, 156.33 End of second year, 1.05x156.33 + 156.33 End of third year, 1.05 x 156.33 + 1.05 x 156.33 -1- 156.33 End of fourth year, 1 . 05*x 156.33 + 1 . 05^x 156.33 + 1.05 x 156.33 + 156.33 End of 18th year, 1.051^ x 156.33 + 1.05i« x 156.33 + 1.05 X 156.33 + 156.33 = $4402.25 If R is taken as the rate of interest; n = number of years and- the loss for the first year is $1. This may be written: 1 — Cl 4- R)^ 1+ (l+i?) + (l + i?)2 + (i+i?)3 + (l+i?)-i = l-\l+R) which may be put into this form q , ^\n _ j R NOTES ON POWER PLANT DESIGN 139 One dollar lost each year plus the interest which would have accrued would at the end of n (1 + i?)° — 1 years amount to -^ ^ which is the "annuity value of one dollar." In the case just considered this gives (1 + .05)18 - 1 .05 = 28.16 28.16 X 156.33 = $4402.25 A guarantee on the duty of a 12,000,000 gallon pump read as follows: "With steam at the throttle of 150 lbs. gage pressure and containing not over IJ^ per cent moisture, the pump is guaran- teed when pumping 12,000,000 U. S. gallons in 24 hours against a total head of 200 feet to give a duty of 140,000,000 per 1000 lbs. of steam." "Should the pump fail to make the duty guaranteed an amount representing the monetary loss suffered by the city in a period of 20 years, takeft as the life of the pimap, is to be deducted from the original contract price of the pump." "The amount to be deducted per 1,000,000 loss of duty as calculated and mutually agreed upon by engineers representing the city and the contractor is $2116.41." "The extra cost of coal per year per million loss of duty, figured on coal at $4.60 a ton with an evaporation of 10 lbs. of water per pound of coal and on the basis that the pump runs only 90 per cent of the year and that it runs at 5/6 of its rated capacity is $63.94." The annuity value of $1 for 20 years a?b 5 per cent is $33.1. 63.94 X 33.1 = $2116.41. The calculations are outlined below: , 365. X .9 = 328.5 days 12,000,000 X 5/6 = 10,000,000 gals, per 24 hours. 328.5 X 10,000,000 X 8.33 x 200 = ft. lbs. per year. Ft. lbs. per year 140,000,000 steam used per year ^^ 1000 - "^^ ,092 (A) Ft. lbs. per year 139,000,000 steam used per year oqq^a m\ 1000 = "^^^^^ ^^^ B A Steam per year 39,370,000 39,092,000 Coal per year, lbs. 3,937,000 3,909,200 ^ Coal per year, tons 1968.5 1954.6 13.9 13.9 X 4.60 = $63.94 63.94 X 33.1 = $2116.41 140 NOTES ON POWER PLANT DESIGN PIPING Steel pipe is cheaper than wrought iron pipe and is generally furnished when an order is given for pipe unless wrought iron pipe is specifically called for. There are two weights of pipe in addition to the Extra Strong and Double Extra Strong one known as "Merchant," and the other known as "Card" or "Full Weight" pipe. The term "Standard" or "Merchant," is used to describe a pipe not "Card" or "Full Weight." For many purposes this lighter weight is just as good as the "Full Weight." The term "Card" or "Full Weight" refers to a pipe of weights as given in the table which follows. Pipe in sizes up to and including 12" refers to inside dia. Above 12" the pipe is rated by the outside dia. Pipe comes in lengths of from 18 ft. to 21 ft. and in figuring the cost of a system of piping there is some waste pipe which must be taken account of. Pages 141 to 154 are taken from the catalogue of the Walworth Mfg. Co. The discounts vary from time to time but may be assumed as being approximately correct. The coefficient of expansion of steel piping is .0000065 or in other words, a pipe expands .0000065 its length per degree F. The expansion on high pressure work is taken care of by expansion bends similar to those shown on the plot (page 155). The amount of motion such bends will provide for has been determined experimentally by the Crane Company. The results of this work were published in the Valve World of October, 1915. This plot is reproduced from that paper. If the total expansion to be taken up by a double offset or U bend is 5" in general, the bend or offset would be sprung apart one-half the expansion, or in this case 2^/^" when the pipe was erected. By this means the expansion first relieves the stress, then puts into the pipe a stress of the opposite kind but of equal amount. Much of the high pressure piping put up to-day has outlets, taking the place of cast tees, welded to the pipe. This saves joints and thereby reduces the trouble from leaky gaskets. The labor cost of the erection of piping depends upon the design of the system; in general however, for the ordinary power house the cost varies from 15 per cent to 25 per cent of the first cost of the fabricated material; 15 per cent would be considered a low cost; 20 per cent about an average value. Card or Full Weight pipe is generally used for pressures carried in power plants. The discount on card or Full Weight is 68 per cent. The discount on Extra Strong 62 per cent; on Double Extra Strong 45 per cent. NOTES ON POWER PLANT DESIGN 141 PRICE LIST OF WROUGHT IRON AND STEEL PIPE. Nominal Inside Diameter. STANDARD. 1 EXTRA STRONG. I DOUBLE EXTRA STRONG. | Price Per Foot. Nominal Weight Per Foot. Price Per Foot. Nominal Weight Per Foot. Price Per Foot. Nominal Weight Per Foot. i,s .05y2 0.24 .11 0.29 % .OSVa 0.42 11 0.54 % 1 .051/2 0.56 11 0.74 .25 96 1/2 I .081/2 0.85 .12 1.09 .25 1.70 % .111/2 1.12 15 1.39 .30 2.44 1 .levs 1.67 .22 2.17 .37 3.65 l',4 .221/3 2.24 .30 3.00 .52 5.20 11/2 .27 2.68 .36 3.63 65 6.40 2- .36 3.61 .50 5.02 95 9.02 21/2 .571/2 5.74 .81 7.67 1.37 13.68 3 .751/2 7.54 1.05 10.25 1.92 18.56 31,4 .95 9.00 1.33 12.47 2.45 22.75 4 1.08 10.66 1.50 14.97 2.85 27.48 4V2 1.30 12.49 1.95 18.22 3.30 32.53 5 1.45 14.50 2.16 20.54 3.80 38.12 6 1.88 18.76 2.90 28.58 5.30 53.11 7 2.35 23.27 3.80 37.67 6.25 62.38 8 2.50 25.00 8 2.82 28.18 4.30 43.00 7.20 71.62 9 3.40 33.70 5.00 48.73 10 3.50 35.00 10 4.00 40.00 5.50 54.74 12 4.50 45.00 6.50 65.42 . 12 4.90 49.00 On orders for 8-incli, 10-inch, 12-inch pipe we will ship 8-inch, 25 lb.. 10-inch, 35 lb., 12-inch, 45 lb., Unless otherwise specified. Customers should, however, always indicate which weight is wanted. When Standard Pipe is ordered, black pipe, random lengths, with threads and couplings, will be shipped^ unless otherwise specified. For pipe smoothed on the inside, known as plugged and reamed, an extra charge will be made above regular pipe. Extra Strong and Double Extra Strong Pipe will be shipped in random lengths and plain ends, unless otherwise ordered. For this pipe, fitted with threads and couplings, an extra charge will be made above regular. For cut lengths of any pipe, an extra charge will be made above random lengths. For galvanized or asphalted pipe, an extra charge will be made above black. For Price List for Cutting and Threading, see page 79. GALVANIZED FLANGED FITTINGS. Faced and Drilled. Size. Inches. 90" Elbows. Galvanized 45" Elbows. Galvanized. Tees. Galvanized. Reducing Tees. Galvanized. Crosses. Galvanized. Y-Branches. Galvanized. 3 2.80 2.35 4.40 4.75 5.85 , 4 4.00 3.70 6.40 7.00 9.70 9.90 5 5.50 4.90 8.00 8.80 12.00 12.60 6 6.40 5.50 9.20 9.80 13.50 16.50 7 8.00 6.00 11.20 12.00 19.00 18.70 8 12.^0 9.50 18.00 19.00 31.00 27.00 9 17.00 14.00 22.50 24.00 40.00 37.50 10 19.20 15.00 26.00 28.00 50.00 50.00 12 26.60 22.00 41.00 44.00 72.00 71.00 14 41.70 24.00 61.00 66.00 86.00 100.00 15 53.00 30.00 76.00 82.00 108.00 116.00 16 76.00 49.00 113.50 122.00 138.00 168.00 18 91.00 70.00 148.00 159.00 174.00 191.00 20 120.00 84.00 157.00 168.00 197.00 208.00 22 142.00 100.00 206.00 222.00 260.00 266.00 24 178.00 122.00 253.00 272.00 325.00 336.00 The above list is for fittings drilled in accordance with SPIRAL PIPE STANDARD. These fittings are also furnished flanged and drilled in accordance with A. S. M. E., Standard at an additional cost. Base elbows for supporting vertical runs furnished as ordered. SPIRAL RIVETED GALVANIZED PRESSURE PIPE. Lengths up to 20 Feet. Size. Inches. U.S. Standard Gauge. Per Foot. Galvanized. No Flanges. * Flanges Attached. Each. ** Diameter Flanges. Inches. Bolt Circle. Inches. No. of Bolts. Size Bolts. Inches. 3 1 20 1 .474 1.90 6 4% 4 Vie 4 18 1 .680 2.30 7 51=/l6 8 yi6 5 18 1 .826 2.70 8 6'yio 8 '/,<, 6 16 1.04 3.15 9 Vk 8 1/2 7 16 1.216 3.40 10 9 8 1/2 1 8 16 1.395 4.05 11 10 8 1/2 9 16 1.564 4.90 13 ' HI/4 8 li. 10 16 1.731 1 5.45 14 12Vi 1 8 1/2 12 16 2.067 1 5.85 16 141/4 1 12 1/2 14 14 2.91 1 6.80 18 16U 12 1/2 15 14 3.12 9.35 19 17-/1 12 1/' 16 14 3.33 11.00 2114 19'/4 12 y2 18 14 3.66 13.35 231/4 211/t 16 % 20 14 4.06 1 15.85 251/4 1 23i,'8 16 % 22 12 5.91 1 20.25 281/4 26 16 % 24 12 1 6.41 1 22.70 30, 27% 16 % •Flanges Drilled. ■•■•Spiral Pipe Diameters. Additional price charged for A. S. M. E. Standard Diameters. The discount on Spiral Riveted pipe is 403per cent, iron or flanged fittings. Galvanized fittings cost 15 per cent, more than the net price of ordinary cast 142 NOTES ON POWER PLANT DESIGN TABLE OF DIMENSIONS OF *CARD OR FULL WEIGHT WROUGHT IRON OR STEEL PIPE. Foir Steam, Water and Gas. Nomi- nal Inside Diam. Ins. Actual Outside Diameter. lnche.s. Approx. Inside Diameter. Inches. Approx. Thick- ness. Inches. Length of Pipe per Sq. Ft. of Outside Surface. Feet Inside Area. Inches. Length of Pipe Con- taining One Cu. Ft. Feet. ••Nomi. nal Weight per Ft Pounds. No. of Threads per Inch of Saew. Contents in •*»Gals. per Ft. Vs .405 .270 .068 9.44 .0568 2513. .24 27 .0006 Vi .54 .364 .088 7.075 .1041 1383.3 .42 18 .0026 % .675 .494 .091 5.657 .1909 751.5 .56 18 .0057 V2 .84 .623 .109 4.547 .3039 472.4 .85 14 .0102 % 1.05 .824 .113 3.637 .5333 270. 1.12 14 .0230 1 1.315 1.048 .134 2.903 .8609 166.9 1.67 IIV2 .0408 1% 1.66 1.380 .140 2.301 1.496 96.25 2.24 IIV2 .0638 iy2 1.90 1.611 .145 2.010 2.038 70.65 2.68 IIV2 .0918 2 2.375 2.067 .154 1.608 3.355 42.91 3.61 IIV2 .1632 2;^ 2.875 2.468 .204 1.328 4.780 30.11 5.74 8 .2550 3 3.50 3.067 .217 1.091 7.388 19.49 7.54 8 .3673 3V2 4.00 3.548 .226 .955 9.887 14.56 9.00 8 .4998 4 4.50 4.026 .237 .849 12.730 11.31 10.66 8 .6528 4^2 5.00 4.508 .246 .765 15.961 9.03 12.49 8 .8263 5 5.563 5.045 .259 .687 19.985 7.20 14.50 8 1.020 6 6.625 6.065 .280 .577 28.886 4.98 18.76 8 1.469 7 7.625 7.023 .301 .501 38.743 3.72 23.27 8 1.999 8 8.625 7.982 .322 .444 50.021 2.88 28.18 8 2.6U 9 9.625 8.937 .344 .397 62.722 2.29 33.70 8 3.300 10 10.75 10.019 .366 .355 78.822 1.82 40.00 8 4.081 12 12.75 12.000 .375 .299 113.098 1.270 49.00 8 5.87 "MERCHANT WEIGHT" WROUGHT IRON OR STEEL PIPE. 8-INCH, lO-mCH, 12-INCH SIZES. Nomi- nal Inside Diam. Ins. Actual Outside Diameter. Inches. Approx. Inside Diameter. Inches. Approx. Thick- ness. Inches. Length of Pipe per Sq. Ft. of Outside Surface. Feet. Inside Area. Inches. Length of Pipe Con- taining One Cu. Ft. Feet. **Nomi- nal Weight per Ft Pounds. No. of Threads per Inch of Screw. Contents in "'Gals, per Ft 8 1 8.625 1 8.073 .276 | .444 | 51.187] 2.81 | 25.00 | 8 | 2.659 10 1 10.750 1 10.138 .306 .355 | 80.715 1 1.78 35.00 | 8 | 4.190 12 1 12.750 1 12.094 | .328 .299 1 114.875 1 1.25 45.00 | 8 | 5.967 *EXTRA STRONG WROUGHT IRON OR STEEL PIPE. _ . * DOUBLE EXTRA STRONG WROUGHT IRON OR STEEL PIPE. Nominal Inside Diam. Inches. Approx. Inside Diameter. Inches. Actual Outside Diameter, tnches. Approx. Thickness. Inches. Length of Rpe per Square Foot of Outside Surface. Feet Inside Area. Square Inches. **Nominal Weight per Foot Pounds. Nominal Inside Diam. Inches. Approx. Inside Diameter. Inches. Actual Outside Diameter. Inches. Approx. Thickness. Inches. Length of Pipe per Square Foot of Outside Surface. Feet Inside Area. Square Inches. **Nominal Weight per Foot Pounds. Vb .205 .405 .10 9.433 .033 .29 ?'s .230 .675 220 5.660 .041 .96 Vi .294 .54 .123 7.075 .068 .54 % .421 .675 .127 5.657 .139 .74 % .244 .84 .298 4.547 .047 1.70 1/2 .542 .84 .149 4.547 .231 1.09 % .422 1.05 314 3.637 .140 2.44 % .736 1.05 .157 3.637 .425 1.39 1 .587 1.315 .364 2.904 .271 3.65 1 .951 1.315 .182 2.904 .710 2.17 VA 1.272 1.66 .194 2.301 1.271 3.00 VA .885 1.66 .388 2.304 .615 5.20 . W2 1.494 1.90 .203 2.010 1 1.753 3.63 IV2 1.088 1.90 1 .406 2.010 .930 6.40 2 1.933 2.375 .221 1.608 1 2.935 5.02 2 1.491 2.375 .442 1.608 1.744 9.02 2y2 2.315 2.875 .280 1.328 4.209 7.67 3 2.892 3.50 .304 1.091 1 6.569 10.25 2y2 1.755 2.875 .560 1.328 2.419 13.68 3y2 3.358 4.00 .321 .955 8.856 12.47 3 2.284 3.50 .608 1.091 4.097 18.56 4 3.818 4.50 .341 .849 1 11.449 14.97 SVa • 2.716 4.00 .642 .955 5.794 22.75 4>/2 4.280 5.00 .360 .764 1 14.387 18.22 4 3.136 1 4.50 1 .682 .849 7.724 27.48 5 4.813 5.563 .375 .687 1 18.193 20.54 6 5.751 6.625 .437 .577 1 25.976 28.58 4y2 3.564 5.00 .718 .764 9.976 32.53 7 6.625 7.625 .500 .501 1 34.472 37.67 5 4.063 5.563 1 .75 .687 12.965 38.12 8' 1 7.625 8.625 .500 .443 1 45.664 43.00 6 4.875 6.625 .875 .577 18.665 53.11 9 1 8.62 9.62 .500 .397 1 58.426 48.25 7 5.875 1 7.625 .875 .501 27.109 62.38 10 1 9.75 10.75 .500 .355 74.662 54.00 12 1 11.75 12.75 .500 .299 1 108.430 65.00 8 6.875 8.625 .875 .443 37.122 71.62 NOTES ON POWER PLANT DESIGN 143 DIMENSIONS OF STANDARD WEIGHT CAST IRON SCREWED FITTINGS. For Steam Working Pressures up to 125 Lbs. 11 i2_18 81 32 Size Inches % % Vs % 1 1% 1^2 2 2y2 3 3y2 4 4y2 5 6 7 8 9 10 12 A-Center to Face.Inches % % IVio 1%6 iy2 ll?i6 2 2% 2ys '36A0 3Hi6 4 4%6 4iyi6 55/10 eyio 6"A6 7y2 8y4 9%«f AA-Face to Face.Inches IV2 1% 2^8 2% 3 3% 4 4% 5% 6% 7% 8 syg . 9% 10% i2y8 13% 15 i6y2 i9y8 B-Center to Face.Inches %c %G His i%o 1%6 IWe l?io 1% 1% lys 2%6 2y4 2yi6 2%e 2i?ie 3y8 3%6 3y8 45/16 478 C-Center to Face.Inches ... 1%6 1% 2%6 2y2 3 31,4 4 5 5% 6% 7y8 778- 8^2 91%6 iiy* 1215/10 i4y2 16 — D-Face to Face.Inches ... 2IA0 2%fl ■ 2% 3^4 3% 43/4 SVa eme 7% 8% 9% ioy2 11%6 isyg 14% 161%6 19 2oy8 ... X-Centerto Back 1 T„^t,oe of Thread.- r"<=h^ % Via %6 % Ys lys 1%6 1^2 m 2%6 2% 2% 3%8 3yio 3i%o 4%6 53/16 5% 6y2 711/16 Y-CentertoBack ( t„^^„, of Thread.. 1^"^^^ Via Vs %e 1/4 S/^6 % % y2 % % 1 lys 1%6 1%« l%e 1% 115^6 2y8 2%6 3 Z-CentertoBack / , ^. ^ of Thread., i^"^*^^ ... 1 1% 11/2 1% 25/ie 2%6 sys 4 4% 5%6 6 6% 7y4 8%6 9% 115/8 12% im — DIMENSIONS OF EXTRA HEAVY CAST IRON SCREW FITTINGS. For Steam Working Pressures to 250 Lbs. 331 332 333 334. Size . Inches y2 % 1 iy4 iy2 2 272 3 372 4 472 5 6 ... A-Center to Face Inches 15/32 1% 11%2 115A6 2yi6 272 3 31716 4y32 415/'32 42732 5732 51 %6 ... AA-Face to Face Inches 25/16 2% 3%6 378 478 5 6 7% 8%6 816/16 9i7i6 lO^Ae 115/8 ... B-Center to Face ■. Inches % Vs 1 1%6 ly* iy2 1% 2% 2%« 21%6 278 378 35A8 ... E-Outside Diameter of Bead—Inches 12yS2 1=^%2 25/16 2% 3^6 3% 4%6 5% 6 613A6 7% 715A6 95A6 — . F-Widthof Bead Inches %e y2 %6 1^6 % 78 1 17* 15/le 1%6 19/16 11%*^ -1% — . G-Thread Length Inches %6 % 11^6 i%e % 1 178 1% 1%6 1%.6 11M6 ll?l6 178 X-Centerto Back of Thread..Inches 1%2 % 2%2 lys 15A6 15/'8 2 25/18 2^6 27i6 21%6 3?l6 315A6 ■Y-Center to Back of Thread.. Inches %6 % 5/16 % % 72 % 1 178 1%6 15A6 1%6 ... 144 NOTES ON POWER PLANT DESIGN STANDARD WEIGHT. CAST IRON SCREWED FITTINGS. 125 Lbs. Working Pressure. STRAIGHT ELBOWS. REDUCING ELBOWS. Size ..Inches | Vi % 1/2 % 1 IVi 11'2 2 21/2 1 3 Size Inches | % V2 | % 1 VA IV2 1 2 21/2 3 1 3y2 Fig. 11, R. H Eacli 1 .05 .05 .06 .08 .101/2 .16 .20 .28 .50 .75 Fig. 13-.__ - Each 1 .06 .07 | .09 .12 .18 .23 1 .32 .60 .85 | 1.20 R. H. Galvanized-_.Each .10 .10 .12 .16 .21 .32 .40 .56 1.00 1 1.50 Galvanized _.. Each 1 .12 .14 | .18 ^24 .36 .46 1 .64 1.20 1.70 2.40 Fig.l2, R.andL._..Each .06 .06 .07 .09 .12 .18 .23 .32 .60 .85 Size _._. Inches | 4 41/2] 5 6 7 8 9 10 12 i .-.- Size Inches | SVi 4 41/2 5 6 7 8 9 10 1 12 Fig. 13 Each |l.40 2.00 1 2.30 3.15 5.40 7.75 1 10.50 15.50 23.00 ___. Fig. 11, R. H Each 1 1.05 1.20 1.75 2.00 2.75 4.70 6.75 9.00 13.50 20.00 Galvanized ___ Each I2.8O 4.00 1 4.60 6.30 10.80 15.50 1 21.00 31.00 1 46.00 1 .— R. H. Galvanized-. .Each | 2.10 2.40 3.50 4.00 5.50 9.40 13.50 18.00 27.00 40.00 For Elbows tapped left hand use Right and Left Elbow List. Ri^ht and Left Hand Elbows have ribs on the band of the end that is tapped left hand. ELBOWS 45°. SIDE OUTLET ELBOWS. Size .Inches ',i % V2 % 1 VA 11/2 2 21/0 3 Fig. 21 _.__ ...Each .06 .06 .07 .10 .12 .19 .24 .34 .60 .90 Galvanized- ...Each .12 .12 .14 .20 .24 .38 .48 .68 1.20 1.80 Size .Inches 3Vi 4 41/2 5 6 7 8 9 10 12 Fig.21_... ...Each 1.25 1.45 2.20 2.50 3.45 5.90 8.50 11.25 17.00 25.00 Galvanized. ...Each 2.50 2.90 4.40 5,00 6.90 11.80 17.00 22.50 34.00 50.00 Size ..Inches V2 % 1 1% W2 2 2V2 3 1 3% Fig. 22 ...Each .18 .24 .30 .48 .60 .84 1.50 2.25 3.15 Galvanized. . ..Each .36 .48 .60 .96 1.20 1.68 3.00 4.50 6.30 Size ..Inches 4 4V2 5 6 7 8 9 10 12 Fig. 22 ...Each 3.60 5.25 6.00 8.25 14.00 20,00 26.00 40.00 60.00 Galvanized _ Each 7.20 10.50 12.00 16.50 28.00 40.00 52.00 80.00 120.00 STRAIGHT TEES. REDUCING TEES. Size ..Inches % % 1/2 % 1 1% IJ/2 2 21/2 3 ■: Size .Inches :<: V2 % 1 1 lU IV2 2 2'/2 3 3"2 Fig.31__._ ...Each .08 .08 .09 .12 .15 .23 .29 .41 .73 1.10 Fig. 32 .... - . . Each .09 .10 .14 .17 1 .27 .33 .47 .83 1.25 1 1.75 Galvanized. ...Each .16 .16 .18 .24 .30 .46 .58 .82 1.46 2.20 Galvanized. ...Each .18 .20 .28 .34 1 .54 .66 .94 1.66 2.50 3.50 Size ..Inches 3'/2 4 414 5 6 7 8 9 10 12 Size ..Inches 4 41/2 5 6 1 7 8 9 10 12 Fig. 31 .... ...Each 1.50 1.75 2.55 3.00 4.00 6.80 9.75 13.00 19.50 29.00 Fig. 32..... ...Each 2.00 2.95 3.50 4.60 1 7.80 11.25 15.00 22.50 33.50 Galvanized. ...Each 3.00 3.50 5.10 6.00 8-00 13.60 19.50 26.00 39.00 58.00 Galvanized ...Each 4.00 5.90 7.00 9.20 Il5.60 22.50 30.00 45.00 67.00 STRAIGHT SIZES. The largest opening of Reducing Fittings determines the list price. CROSSES. REDUCING SIZES. Size ..Inches % V2 % 1 IVi 1 IV2 2 21/2 3 1 3'/2 Size . Inches V' ?i 1 1% 11/2 2 21/2 3 •31/3 Fig. 51.. . —Each .15 .16 .22 .27 1 .42 1 .53 .75 1.30 2.00 1 2.70 -Fig. 52 ...Each .18 .25 .30 .46 .60 .83 1.45 2.20 3,00 Galvanized .. Each .30 .32 .44 .54 1 .84 1.06 1.50 2.60 4.00 5.40 Galvanized. Each .36 .50 .60 .92 1.20 1.66 2.90 4.40 6.00 Size __ Inches 4 4Vi 5 6 1 7. 1 8 9 10 12 |._.. Size .-Inches 4 4V2 5 6 7 8 9 10 12 Fig. 51 ...Each 3.15 4.60 5.50 7.25 1 12.25 17.50 23.50 35.00 52.50|_... Fig. 52 ...Each 3.50 5.10 6.00 8.00 13.50 19.25 26.00 38.50 58.00 Galvanized . ...Each 6.30 9.20 11.00 14.50 1 24.50 1 35.00 47.00 70.00 105.00|-..- Galvanized. ...Each 7.00 10.20 12.00 16.00 27.00 38.50 52.00 77.00 116.00 REDUCING COUPLINGS. REGULAR PATTERN, The largest opening of Reccing Fittings determines the list price. ECCENTRIC REDUCING COUPLINGS. Size ...Inches 2 21/2 3 31/2 4 41/2 5 6 7 8 9 10 12 Fig. 61... Each .43 .60 .80 1.00 1.35 1.85 2.00 2.70 5.35 6.75 8.35 10.00 15.00 Galvanized ... .86 1.20 1.60 2.00 2.70 3.70 4.00 5.40 10.70 13.50 16.70 20.00 30.00 Size ...Inches 1 IVt V/2 2 2y2 3 3% 4 Fig. 62.. .Each -.50 .55 .72 1.00 1.50 2.40 3.00 4.00 1 Size... Inches 41/2 5 6 7 8 9 . 10 12 ' Fig. 62.. -Each 5.00 6.00 8.00 9.00 11.00 12.50 14.00 18.00 1 The largest opening of Reducing Fittings determines the list price. Discount 60 and 10 NOTES ON POWER PLANT DESIGN 145 DIMENSIONS OF EXTRA HEAVY CAST IRON FLANGED FITTINGS. For Steam Working Pressures up to 250 Lbs. K— C ^-A--! 971 981 973 ^1 f--- Alk 991 1101 K- A— ^--A— 1 rn? h-B-H 1021 1022 1012 Size Inches 1% t 1% 2 21/2 3 3y2 4 4% 5 AA-Face to Face 8% 1 9 10 11 12 13 14 15 16 A-Center to Face 41/4 1 41/2 5 51/2 6 6V2 7 7V2 8 B-Centerto Face 41/4 1 41/2 5 51/2 6 6I/2 7 772 8 C-Center to Face _..- 1 61/2 7 7% 81/2 9 91/2 101/4 D-Radius .__. 1 51/4 5% 6I/4 evs 7% 73/4 81/2 E-Center to Face ...^ 21/2 1 2% 3 31/2 3y2 4 4% 41/2 5 Size Inches 6 1 7 8 9 10 12 14 15 16 AA-Face to Face 17 1 18 20 21 23 26 29 30 32 A-Ceriter to Face 81/2 1 9 10 101/2 111/2 13 141/2 15 16 B-Center to Face .... 8y2| 9 10 101/2 111/2 13 141/2 15 16 C-Centerto Face 111/2 1 12% 14 151/4 I6I/2 19 211/2 22% 24 D-Radius 9% 1 loys 12 13 141/8 161/2 1878 20 2iy4 E-Center to Face 51/2 1 6 6 6I/2 7 8 8 81/2 9 All Reducing Fittings, IVi inches to 9 inches inclusive, are the same dimensions, Center to Face, as straight sizes. For Dimensions of Reducing Fittings 10 inches and larger, see lower table. Size Inches | 10 12 1 14 15 1 16 18 1 20 22 24 Size of Outlets | 6 and 1 8 and 1 9 and 9 and 10 and 1 12 and 1 14 and 1 15 and 1 15 and SmallerlSmallerlSmaller Smaller Smaller|Smaller|SmallerlSmaller|SmaIler AA-Face to Face of Run | 18 21 1 22 23 1 24 27 1 30 30 30 A-Center toFace of Run | 9 101/2 1 11 111/2 1 12 13y2| 15 15 15 B-Cen.to Face of Outlet] 11 121/2 1 131/2 131/2 1 15 I61/2 1 171/2 18y2 191/2 146 NOTES ON POWER PLANT DESIGN Straight Tee. EXTRA HEAVY. CAST IRON FLANGED FITTINGS. 250 Lbs. Working Pressure. Reducing Tee. FIGURE 1011. FIGURE 1012. 1 Size. Inches. Faced Only. Each. Faced and Drilled. Each. Center to Face. Inches. Face to Face. Inches. Diam. of Flanges. Inches. Size. Inches. Faced Only. Each. Faced and Drilled. Each. Center to Face. Inches. Face to Face. Inches. 2 7.00 8.50 5 10 6I/2 2 8.00 9.50 i n a, 1982 Size Inches 21/2 3y2 4 4% A-End to End Inches IOV2 IIV2 12% 13 14 14% 161/2 "I -Center to End ._ -Inches 5% 5% 63/8 6I/2 1% 81/i B-Face to Face Inches 111/2 121/2 131/2 14 15 15% 171/2 ^-Center to Face Inches 5% 6% 6% 71/2 VA 8% C-Center to Top, Closed Inches 13 14 15% 16% 171/2 18 20 D-Center to Top, Open Inches 141/2 15% 17% 19 20 20% 231/2 E-Diameter ofWheel Inches 12 12 14 16 F-Diameter of Flange Inches 71/2 81/^ 10 101/2 11 I2V2 G-Thickness of Flange Inches 1%. 11/^ 15/lC 1% F/k Size -• Inches 10 12 B-Face to Face Inches 191/4 21 241/2 28 § -Center to Face Inches 9% 101/2 121/4 14 C-Center to Top, Closed Inches 211/2 25 28 32 D-Center to Top, Open Inches 25i/4 29 33 38 E-Diameter of Wheel Inches 16 20 24 30 F-Diameter of Flange Inches 14 15 171/2 20 G-Thickness of Flange Inches 11/2 1% V/s Size Inches 21/2 3y2 Globe or Angle Valves, Screwed Ends Each 33.00 37.00 42.00 46.00 Globe or Angle Valves, Flanged Ends Each 35.00 40.00 45.00 50.00 Fig. 1981, Drilling Each .75 .75 1.00 1.25 Fig. 1982, Dialling Each 1.25 1.25 1.50 1.75 Size _' Inches 41/2 Globe or Angle Valves, Screwed Ends Each 56.00 61.00 75.00 Globe or Angle Valves, Flanged Ends Each 60.00 65.00 80.00 Fig. 1981, Drilling Each 1.50 1.50 1.75 Fig. 1982, Drilling Each 2.00 2.00 2.50 Size Inches 10 12 Globe or Angle Valves, Flanged Ends Each 100.00 120.00 200.00 300.00 Fig. 1981, Drilling Each 2.25 2.25 2.50 3.5o Fig. 1982, Drilling Each 3.00 3.00 3.50 5.00 Discount 60 per cent. NOTES ON POWER PLANT DESIGN PRILLING TEMPLATES FOR FLANGED VALVES, FLANGED FITTINGS AND FLANGES. 250 Lbs. Working Pressure. 153 size. Inches. Diameter of Flanaes. Thickness of Flanges. Bolt Circle. Number of Bolts. Size of Bolts. Length of Bolts. 1 4% ^%6 m 4 % 2 IVi 5 % 3% 4 % 2y4 1% 6 i?ie 4% '4 % 2% 2 m % 5 4 % 2% 2V2 m 1 5% 4 % 3 3 &Vi 1% 6% 8 % 3 3% 9 l%e n'i 8 % SVi 4 10 IH 7% 8 % 3% 4H WVi 1%6 8% 8 % 3% 5 - 11 1% 9% 8 % 3% 6 12^! I'Ae 10% 12 % 3% 7 14 1% 11% 12 Vs 4 6 15 1% 13 12 % m 9 16% 1%, 14 12 1 4% 10 17% 1% 15H 16 1 4% 12 20 2 17% 16 1 5 14 22% 2% 20 20 1 5% 15 23% ' 2?46 21 20 1% 5% 16 25 2% 22% 20 1% 5% 18 27 2% 24% 24 1% 6 20 29% 2% 26% 24 IH 6% 22 31% 2% 28y4 28 ly* 6% 24 34W 2% 3Wi 28 1% 7 From Wall to Center of Pipe, Adjustable ^ fnthes Horizontal Center between Wall Bolts Inches Vertical Center between Wall Bolts , Incl,g3 From Wall to End of Bracket. _.^ j^ Price, including Wall Bolts -Each 15 to 19 18% 27 28.00 Discount on Cast Iron Rolls, Chains and Wall Brackets 373^ per cent. 154 NOTES ON POWER PLANT DESIGN SEAMLESS DRAWN BRASS PIPE. STANDARD IRON PIPE SIZES. Iron Pipe Sizes. Actual Outside Diameter. Actual Inside Diameter. Approximate Wt. per Foot Pounds.* Iron Pipe Sizes. Actual Outside Diameter. Actual Inside Diameter. Approximate Wt per Foot Pounds.* Vs . .405 .281 .25 2'i 2.875 2.5 5.75 H .540 .375 .43 3 3.500 3.062 8.30 % .675 .494 .62 3>/2 4.000 3.5 10.90 1/2 .840 .625 .90 4 4.500 4. 12.7C % 1.050 .822 1.25 414 5.000 4.5 13.90 1 1.315 1.062 1.70 5 5.563 5.062 15.75 1% 1.660 1.368 2.50 6 6.625 6.125 18.31 V/2 1.900 1.6 3.00 7 7.625 7.082 23.73 2 . 2.375 2.062 4.00 8 8.620 7.980 29.88 EXTRA HEAVY IRON PIPE SIZES. Iron Pipe Sizes. Actual Outside Diameter. Actual Inside Diameter. -Approximate Wt. per Foot Pounds.* Iron Pipe Sizes. Actual Outside Diameter. Ac^Jal Inside Diameter. .Approximate VVL per Foot Pounds.* Vs .405 ■ .205 .370 2 2.375 1.933 5.460 M .540 .294 .625 2'b 2.875 2.315 8.300 % .675 .421 .830 3 3.500 2.892 11.200 V2 .840 .542 1.200 3>,i 4.00 3.358 13.700 % 1.050 .736 1.660 4 4.50 3.818 16.500 1 1.315 .951 2.360 5 5.563 4.813 22.800 l^i 1.660 1.272 3.300 6 6.625 5.750 32.00 I'.fe 1.900 1.494 4.250 * Some variation must be expected in these weights. Stock lengths of Is inch to 2 inches Standard Weight Pipe average 16 feet in length ; 2Vi inches to 4 inches, 14 feet to 16 feet ; 5 inches to 6 inches, 10 feet to 12 feet Stocl< lengths of Extra Heavy Pipe run somewhat shorter than Standard Weight BRASS FITTINGS. EXTRA HEAVY— IRON PIPE SIZE. CAST IRON PJ^TTERN. For 250 Lbs. Steam Working Pressure. TEES, CROSSES, AND Y BENDS. BRASS FLANGED FITTINGS STANDARD WEIGHT. For 125 Lbs. Size Inches 1 I4 1 1 lU ! lU- 2ij Size Inches 3K. I 4 41^ Elbows, 90°. Faced Each 25.00 33.75 43.75 58.75 68.00, 78.00 93.00123.00 90O, Faced and Drilled. ...Each 26.00 35.00 45.00 60.00 70.00 80.00 95.001125.00 Elbows, 450, Faced Each 27.50 37.25 47.75, 63.75,73.00 83.00 98.00,133.00 45", Faced and Drilled Each 28.50 38.50 49.00 65.001 75.00 85.00 100.00 135.00 Tees. Faced __Each 37.50 50.75 65.75 88.25 102.00 117.00137.00187.00 Faced and Drilled Each 39.00 52.50 67.50 90.00 105.00 120.00 140.00 190.00 Tees Each I 35 1 .40 .65 1.00 1.35 i 2.00 3.00 4.50 1 7.50 11.00 16.50 20.00 Crosses, Faced Each 50.00 67.50 87.50 117.50 136.00156.00186.00 246.00 Tecs, Reducing -Each .46 ' .75 1.15' 1.55 2.30 3.45 ' 5.20 ' 8.60 12.65 .-_ ! 22.00 Faced and Drilled .Each 52.00,70.00 90.00 120.00 140.00 160.00 190.00 250.00 Crosses. . Each .90 1.301 1.80 2.75 4.00 ' 5.25 ' 9.00 14.00 21.00: 27.00 Companion Flanges, Faced ...Each 10.75 12.5015.50 19.25 24.25 26.75 29.00 36.50 Crosses. Red Each .. 11.04 1.50 2.10 I 3.15 i 4.60 ' 6.00 10.35 16.00 24.00 30.00 Faced and Drilled Each 11.0013.0016.00 20.00 25.00 27.50 30.00i 37.50 Y Bends Each 1.30 1.35 2.25 I 2.90 ' 4.25 '. 6.50 i 9.60!l3.25 22.50; 30.00 Finished Fittings at double above lists. ELBOWS. Dimensions same as Standard Weight Cast Iron Fittings. Reducing sizes to order at special prices. EXTRA HEAVY. For 250 Lbs. Steam Working Pressure. Size Inches | ¥4 1 % | V-i \ ^a \ 1 | Ui | IV2 1 2 i 21/2 ^ 3 ! 3V2 i 4 Size -Inches 1 2 ' 2'. ' 3 ! S'i. ! 4 1 4^<2 1 5 I 6 Elbows..-. Each | .25 1 .28 .36 [ .70 i 1.00 ! 1.50 ! 2.00 I 3.00 ' 5.50 i 8.5012.50, 16.00 Elbows. 90", Faced .-Each 125.00 33.75 43.75 58.75 68.00 78.001 93.00123.00 Elbows, Red Each i .. | .32 i .42 1 .80 i 1.15 i 1.72 i 2.30 3.45 i 6.30 1 9.75 14.50 18.50 90", Faced and Drilled ._ -.Each 26.00 35.00 45.00 60.00 70.00! 80.00^ 96.00i 125.00 Elbows, 45", Faced --Each 27.50 37.25 47.75 63.75 73.00' 83.001 98.00133.00 Elbows, R. and L. Each , .. 1 .32 '' .42 i .80 ■ 1.15 1 1.72 2.30 3.45 i 6.30 ! 9.75; ... ! ... 45", Faced and Drilled .. Each 28.50 38.50 49.00 65.00 75.00: 85.00100.00135.00 Elbows, 45° Each ! .35 : .40 .43 1 .84 1 1.20 1 1.80 , 2.40 i 3.60 ■ 6.60 j 10.20 15.50i 20.00 Tees, Faced -Each 37.50 50.75 65.75 88.25102.00117.00137.00187.00 Finished Fittings at double above lists. Faced and Drilled ..Each 39.00 52.50 67.50 90.00105.00120.00140.00190.00 Crosses, Faced Each 50.00 67.50 87.50 117.50 136.00 156.00 186.00 246.00 Faced and Drilled Each 52.00 70.00 90.00! 120.00 140.00 160.00 190.00 250.00 Companion Flanges, Faced. .-Each 1IO.75 12.50 15.501 19.25 24.25 26.75 29.00, 36.50 Facedand Drilled Each 11.0013.0016.001 20.00 25.001 27.501 30.001 37.50 Dimensions same as Extra Heavy Cast Iron Fittings. Reducing sizes to order at special prices, Discount on all brass fittings flanged or screwed, 65 per cent. NOTES ON POWER PLANT DESIGN 155 i||||||||||||n s nil III nil 1 II II 1 11 3r TfTttt — I'll 'i' :J c I |;;;;:;;;:i::;;;;n::;; -'!' a L;j I; :::: :::;:: ii: i ^:::: ^B |;:;;;::;;;;;;:;;;i:|iii > :':! m i TMM ^-^m^m S:H: -::!F;T:^i;:i| : --- :iiq 1: ■ HI :;;;;ii;l;;;; '& m --- + 1 ? :::±::::::::i| ,::: ;!fi li!!:! 1 :::: :::::: >| :::tt: + : : :: it:- U=^ fc ifliil 1 TiT ■ -+--r- IMIIlll 1 1 w :||:::::|::::: :::ti::::g:! 1 ::::::: iC 1 iiiii :: :: :;:::: i::?:: ^jlllllllllllllll |;::::::::::::::::<|:i::|S:::: :!!i 1^1 1 1 (:::::i:^:: lii iH :: ::i: ■ ■ ■ i ■ ■ ■----L.-::::J^:--l::-!f^::- ii:i;it if i'*^ — h T--f- :::i;::::::;±:::*: :( :::: p^ - :: :::: ::|;::::: :: -■( - r ■■": ■■- } - 1 :/: 7=: ■ ( :: ::;: :: (::: :i :::: PI 1^ - ; liip if S:!:^ II 11 : -■ --±-it-- :::;^i: [f: :a::;|;.J:; . - - - - Q- - r^ +1t--- ;|i j^jP fw4mw Mr :::; i::::::::: - ;: : ,!::::!:::: : 1 -j jatt 111111 ttw ]z:±:;l:::-':::(:::t'::: : ■.::::-:ii: '. "f ■ ■t\ ^^i-------r-l /- fE"T^ w LH K K M y :::: ::::::!::: :i :::: :: :: : : ::::l!:i;: :: ; it- ■ i ^^i--: ipH fmTn -^f^ i 5:±!!:::::2 :::::; :::: — :: -I '* ■■ ■ ■ f m i:'i:;::: :: = :;:!,:: :::l;=;;i :: :::^!:|:: ; ;;|;i!^;M;::;s[;|:|;; |::;;;n:l|:i| ::::::: - ^:-:;f±::::::;K:: : Hfi Mtllili- 1 :;;:;;!:;;;!;:;;i;i::-E-;::;;:::;;;p pWiiiiinmife ^'ff :::::!: r? /I kl/K 4?::?:3 i:;|!:!|;;i!;:;:: mi +:::::■ ;:: ■:: ::(:: Em\:iiiv:im ™4 ;4 5' -^' -' Ww = |::: ;. = ::;::::^;;:;:; '^^^^^^ "1^ i^v'3^ffl^ffl4 •HB ?l':^'X i?:;;4 / i:?' :? ::::::::::: ::: ::::::::: ::::::::::::::g:: ffflWff frt ^-^^^ ;|?'|;^=';;;J^=;: ' ;i!: :::::::::: \\\\\\\\\\\ \\] iii]]]\\ !i 1 W ^ ^■'■■' ft 5' ^ W''i ^n :i±::::::::::2E - J ■ '- ■ " ?■-'--.-< i' — ^:: ■.■:i::'ii: ::: hj: :;! s: :;;: : :;;;;;ffi 1^ 1 e||;:^ W^'-'-'~ i ..::::._:::::::::: j«iiwm»mtH H 1 IIIII liM ^^^ m| 1 11 1 1 ly :::.:::::. .... ::;;:::: ::::!::: ■ ■H TmnTi + i!s: i;?! [: h :kl. • ■: ! m s m - niiimiii 1111m ::4:::: :^::: In figuring the cost of a bent pipe, add to the net cost of the pipe and flanger the following for each bend of 90° or less For pipe size 6" 7" 8" 9" 10" 12" add per bend $8 $9 $12 $13 $16 $26 156 NOTES ON POWER PLANT DESIGN CAST IRON PIPE Cast iron pipe may be used to convey cooling water to the power house. This pipe comes in lengths of about twelve feet and has a bell on one end and a spigot on the other. The joint be- tween the bell and spigot is made by pouring in melted lead and then calking with a blunt chisel. A table giving the weights of cast iron pipe is convenient in figuring costs which are taken at a certain rate per ton, the price depending upon the price of pig iron. The price is between and 125 a ton. DIMENSIONS OF CAST IRON PIPE Standard adopted by American Water Works Association. The weight per length refers to length of 12 feet and includes allowance for bell and spigot. Class A, 100 ft. Head Class B, 200 ft .Head Class C, 300 ft. Head Nominal Thick- Weight Lbs. Thick- Weight Lbs. Thick- Weight Lbs. inside ness Ft. Length ness Ft. Length ness Ft. Length dia. In. In. In. 8 .46 42.9 515 .51 47.5 570 ;56 52.1 625 10 .50 57.1 685 .57 63.8 765 .62 70.8 850 12 .54 72.5 870 .62 82.1 985 .68 91.7 1100 14 .57 89.6 1075 .66 102.5 1230 .74 116.7 1400 16 .60 108.3 1300 .70 125.0 1500 .80 143.8 1725 18 .64 129.2 1550 .75 150.0 1800 .87 175.0 2100 20 .67 150.0 1800 .80 175.0 2100 .92 208.2 2500 24 .76 204.2 2450 .89 233.3 2800 1.04 279.2 3350 30 .88 192.7 3500 1.03 333.3 4000 1.20 400.0 4800 36 .99 391.7 4700 1.15 454.2 5450 1.36 545.8 6550 NOTES ON POWER PLANT DESIGN 157 PIPE COVERING The heat radiated from a bare pipe is about 3 B. T. U. per hour per square foot of pipe sur- face per degree difference in temperature between the steam inside the pipe and the air in the room. The saving made by coverings of different thickness is shown by the figures below which apply to a 5" pipe: B. T. U. loss per hour per square foot of surface of 5" pipe per degree diff. in temperature .... Bare Pipe No Covering 3.00 Covering Covering Covering Covering 1/" 72 Thick .67 1' Thick .43 Thick .37 Thick .33 The B. T. U. loss per square foot of pipe surface per hour per degree difference in temperature gradually increases for the covered pipes as the diameter of the pipe decreases, the values for a 2" pipe being about 20 per cent greater than the values given above. For sizes over 5" diameter the values gradually decrease until at 10" diameter, the figures are 10 per cent lower than those given. The efficiency of a covering, or the percentage of heat saved, varies slightly with different cov- erings of the same thickness, in general, however, a covering 3" thick may be assumed to have an efficiency of 88 per cent and one, IM" thick, 85 per cent. The saving per year due to covering an 8" header 200 feet long supplied with steam at 170 lbs. absolute superheated 100° may be figured thus. For high pressure steam, 100 to 150 lbs., the Double Layer Double Standard Thickness sectional covering should be used. This covering should be applied by the broken joint method, each set of sections being thoroughly wired in place. Outside of the sections 3^" of plastic should be added and the whole covered with 8 oz. canvas sewed on. The fittings should be covered with blocks and plastic or with all plastic of a thickness to correspond with the covering on the pipe. The flanges should be covered with removable flange covering made up of blocks and plastic, 2" thick on special netting, and covered with canvas to match the pipe covering. Exhaust piping, feed piping, drips, etc., should be covered with Standard Sectional Covering and with regular canvas jacket. For standard thickness of covering apply 45 per cent discount to list given. For fittings apply 45 per cent. Note that the cost of covering the flanges on an elbow or tee is not included in the cost as given for elbow or tee and is to be added. For superheated steam lines the 3" thickness is advisable. Figure a discount on 3" thickness of 35 per cent. This makes the price of the 3" thickness per lineal foot all installed with canvas jacket : 4" pipe $2.05 for 8" pipe 5" " 2.37 " 10" " 6" " 2.67 " 12" " ^.43 for 1.63 " 1.76 " 1.89 " For fittings covered with 3" thickness use regular fitting prices as per list for Standard Thick- ness and add 10 per cent. Removable flange covers for this thickness of covering would be 2" thick and the cost of these covers is not included in the cost of elbows and tees as given in the price list. The price of these flange covers installed is 10 per cent above the figures given in the right hand column. Boiler drums should be covered with blocks 2" thick and 3^" of plastic added. Such covering costs 35 cents per square foot area of the external surface of the covering. 158 NOTES ON POWER PLANT DESIGN For smoke flues, flues leading to economizers, etc., blocks 1" thick should be wired on and cov- ered with ^2" of plastic. This costs 25 cents a square foot. The outside diameter of 8" pipe is 8.625", the circumference in feet is 2.258. The total surface of 200 ft. of pipe is 451.6 sq. ft. and the B. T. U. loss per year is 365 x 24 X 451.6 X 3 X (468.5 - 68.5) = 4,747,200,000, assuming room to be 68.5° F. If 10,000 B. T. U. are utilized by the boiler per lb. of coal burned, the coal required to supply this loss would be 474,200 lbs. or 237.1 tons. At $4.50 per ton this amounts to $1067. If a covering 3" thick is used, an efficiency of 88 per cent may be assumed. The saving due to the covering becomes .88 x 1067 = $939 per year. The first cost of the covering would be for the 200 feet of pipe 200 x $2.05 = $410 10 pairs of flanges 10 x $2.53 = 25.30 $435.30 The covering would more than pay for itself in six months. The cost of a covering may be figured from the price list, noting the discount given on the different items. PRICE LIST OF 85% MAGNESIA AND ALL OTHER SECTIONAL COVERINGS Price per Price per Price per Inside Standard Line al Lineal Lineal Diameter Thickness Foot Can- Thicliness Foot Can- Thickness Foot Can- of of vas Jaciceted of vas Jacketed of vas Jacketed Pipe Coveri ng Covering Covering 'A" K' $.22 lA' $.46 2" $.75 H" y%' .24 \A' .49 2" .80 1" Vs' .27 \A' .52 2" . .85 IH" ' Vs' .30 lA' .56 2" .90 . Wi" %' .33 lA' .60 2" .95 2" lA' ' .36 lA' .64 2" 1.00 2J^" lA' .40 IK' .70 2" 1.05 3" U' .45 lA' .76 2" 1.15 3J^" lA' .50 lA' .82 2" 1.25 4" 1^'- .60 . \Vi .88 2" 1.35 m" 1%' .65 lA' .94 2" 1.45 5" IVs' .70 lA' 1.00 2" 1.55 6" 1^' .80 lA' 1:10 2" 1.70 7" IM' 1.00 lA' 1.20 2" 1.85 8" IW 1.10 lA' 1.35 2" . 2.00 9" IM' 1.20 lA' 1.50 2" 2.20 10" IK' 1.30 lA' 1.65 2" 2.40 12"* IH' 1.85 \A' 1.85 2" 2.70 14" 1^' 2.10 lA' 2.10 2" 3.00 16" I'A' 2.35 m' 2.35 2" 3.30 18" 1^' 2,60 lA' 2.60 2" 3.60 20" I'A' 2.85 lA' 2.85 2" 4.00 24" m' 3.30 lA' 3.30 2" 4.50 30" iM' 4.00 lA' 4.00 2" 5.50 *A11 coverings above 10 in. furnished in segment form; jackets not included in the prices. NOTES ON POWER PLANT DESIGN 159 PRICE LIST OF 85% MAGNESIA AND ALL OTHER SECTIONAL COVERINGS — Cont. Block List Double Price per Price per Double Price per Price per Layer. Lineal Double Lineal Layer. Lineal Double Lineal Double Foot Can- layer. To- Foot Can- Double Foot Can- layer. To- Foot Can- Standard vas Jack- tal Thick- vas Jack- Standard vas Jack- tal Thick- vas Jack- Thickness eted ness 3 in. eted Thickness eted ness 3 in. eted m" $.65 3" $1.20 K" $.27 2%" $.64 m" .70 3" 1.35 M" .27 2M" .68 iVi" .75 3" 1.40 • %" .30 2%" .72 iVi" .80 3" 1.45 1" .30 W2" .75 iVi" .85 3" 1.55 IH" .34 2%" .79 n 1 II ■''16 .90 3" 1.65 IM" .38 2M" .83 2A" 1.00 3" 1.75 i%" .42 2K" .87 2A" 1.10 3" 1.90 iy2" .45 3" .90 9 1 // •^16 1.20 3" 2.05 i%" .49 31^" .98 2^" 1.40 3" 2.20 m" .53 Z'A" 1.05 2M" 1.50 3" 2.35 W%" .57 4 1.20 2M" 1.60 3" 2.50 2" .60 2K" 1.80 3" 2.70 2>^" 2.25 3" 2.90 2H" 2.50 3" 3.15 W2" 2.70 3" 3.40 2}^" 2.90 3" 3.65 3" 4.10 3" 4.10 3" 4.60 3" 4.60 3" 5.10 3" 5.10 3'^ 5.60 3" 5.60 3" 6.00 3" . 6.00 3" 7.00 3" 7.00 3" 8.40 3" 8.40 Sizes of G. , Flange Fittings Elbows Tees Crosses Valves Covers ¥2" $.30 $.36 $.48 $.54 $.50 M" .30 .36 .48 .54 .50 1" .30 .36 .48 .54 .50 1J€" .30 .36 .48 .54 .50 iy2" .30 .36 .48 .54 .50 2" .36 .42 .54 .60 .60 2J^" .42 .48 .60 .78 .70 3" .48 .54 .70 .96 .80 3^" .54 .60 .80 1.20 .90 4" .60 .75 .95 1.50 1.00 4K" .72 .90 1.10 1.85 1.30 5" .90 1.20 1.50 2.25 1.60 6" 1.30 1.60 2.00 2.80 1.90 7" 1.80 2.20 2.80 3.60 2.20 8" 2.40 3.00 3.60 4.40 2.50 9" 3.00 3.80 4.40 5.30 2.90 10" 3.60 4.60 5.20 6.20 3.30 160 NOTES ON POWER PLANT DESIGN SPECIFICATIONS The specifications for a Condensing Equipment for a 1500 K. W. Low Pressure Steam Turbine; for Automatic Pump and Receiver; for Direct Acting Boiler Feed Pumps and for Turbine Driven Centrifugal Boiler Feed Pumps were furnished by Mr. B. II. T. Collins '88. SPECIFICATIONS FOR CONDENSING EQUIPMENT Including Surface Condenser, Hot Well Pump, Dry Vacuum Pump 1. Number Wanted. One. 2. Type. Surface condenser with separate wet and dry air pumps. 3. Capacity. Amount of steam to be condensed, 000 lbs. per hour. Temperature of injection water, 70° Fahrenheit. Absolute pressure in condenser, 2 inches of mercury or 28 inches vacuum referred to a 30-inch barometer. 4. Character of Circulating Water. Fresh river water. 5. Source op Circulating Water. From factory water supply system. Any quantity up to 000 gallons per min. at any pressure required." 6. Relative Location of Condensing Equipment and Turbine. The surface condenser with the dry air pump will be located directly beneath the horizontal turbine to which it will be connected and as near to it as practicable. The wet or hot well pump can be located as much below this level as required. The exhaust outlet of the turbine will look down. 7. Equipment to be Furnished. The equipment to be furnished includes surface condenser, wet or hot well pump and dry air or dry vacuum pump required to give the results stated under "Capacity." The hot well pump shall be of the duplex direct-acting steam driven type. The dry vacuum pump shall be of the rotative steam driven type. The condenser proper, hot well and dry vacuum pumps are described in detail under sep- arate specifications following. SPECIFICATIONS FOR SURFACE CONDENSER 1. Number Wanted. One. 2. Construction. This surface condenser shall contain not less than 000 sq. ft. of cooling surface. The shell and heads are to be furnished Avith openings for the exhaust steam, circulating water inlet and discharge, dry air and condensed steam, of sizes and locations approved by the Engineer. NOTES ON POWER PLANT DESIGN 161 The tube heads are to be of rolled brass. The tubes are to be seamless drawn brass of the following composition : Copper 60% Zinc 40% Every tube is to be inspected for faults on both inside and outside and all tubes show- ing any indication of imperfection of any kind are to be rejected. The condenser is to be tested under 25 lbs. per sq. in. cold water pressure applied in both steam and water spaces before shipment from the factory and made tight. The interior of the shell is to be carefully painted with two coats of anti-rust metallic paint. The whole exterior is to be scraped, filled and painted with the best lead and oil paint before leaving the shops. All interior bolting in contact with the circulating water is to be of composition unless otherwise specified. 3. Bolts, Etc. Bolts, nuts and screws shall be of the United States standard. 4. Finish. All castings shall be carefully dressed down, filled and painted with the best quality of paint. 5. Drilling. All flanges shall be faced and drilled in accordance with Manufacturers' Standard for flanges and drilling. 6. Design, Material and Workmanship. The design shall be such as to insure safe, reliable and economical operation. The material and workmanship shall be the best of their respective kinds. The contractor shall furnish, without charge, F. O. B. cars, a duplicate of any part that may prove defective in material or workmanship within one year after the condensing equipment has been started. 7. Drawings. Bidder shall submit in connection with his proposal an outline drawing to scale and a description of the condenser he proposes to furnish, giving in detail the design, and arrangement made for removal of parts and for repairs. 8. Condenser Data. The bidder shall furnish the following data on each condenser: Number of tubes Length of tubes ft in. Outside diameter of tubes in. Thickness of tubes No. 18 B. W. G. Thickness of tube heads in. Cooling surface sq. ft. Material of tubes Area exhaust opening Size of circulating water inlet opening in. Size of circulating water discharge opening in. Size dry air opening in. Approximate finished weight lbs. Approximate shipping weight lbs. 162 NOTES ON POWER PLANT DESIGN SPECIFICATION FOR DIRECT ACTING HOT WELL PUMP 1. Number Wanted. One. 2. Type. Horizontal duplex piston type. 3. Kind of Service. Removing condensed steam from surface condenser. 4. Working Steam Pressure. 175 lbs. per sq. in. gage. 5. Minimum Steam Pressure. 125 lbs. per sq. in. gage. 6. Steam Temperature. 527.6° F. (approx.) or 150° superheat. 7. Back Pressure. 17 lbs. per sq. in. absolute. 8. Discharge Water Pressure. Not over 15 ft. head. 9. Capacity. The pump shall be capable of delivering at least gallons of water per minute under the conditions of operation as described in this specification. 10. Water End Fittings. Bronze cylinder linuigs, piston rods, pistons, stuffing box glands, valve seats, bolts, plates and springs. Hard rubber valves for 212° F. water. 11. Lubrication. There shall be furnished with the pump one (1) pint "Detroit" lubricator. 12. Drilling. All flanges shall be faced and drilled in accordance with Manufacturers' Standard for flanges and drillings. 13. Material and Workmanship. The material and workmanship shall be the best of their respective kinds. The Contractor shall furnish without charge F. O. B., a duplicate of any part that may prove defective in material, or workmanship one year after the pump has been started. 14. Drawings. Bidder shall submit in connection with his proposal, an outline drawing to scale and a de- scription of the pump he proposes to furnish, giving all necessary details. 15. Pump Data. Bidder shall furnish the following data on the pump: Diameter steam cylinder ins. Diameter water cylinder ins. Length of stroke ins. Diameter steam inlet ins. Diameter exhaust outlet . ins. Diameter suction ins. Diameter discharge ins. Approximate finished weight lbs. Approximate shipping weight lbs. SPECIFICATION FOR ROTATIVE DRY VACUUM PUMP 1. Number Wanted. One. 2. Type. Horizontal, crank and fly wheel rotative dry vacuum pump. 3. Kind of Service. Removing non-condensible vapors from condenser. 4. Speed. Not over 150 R. P. M. Piston speed not over 300 feet per minute. 5. Working Steam Pressure. 175 lbs. per sq. in. gage. 6. Minimum Steam Pressure. ' 125 lbs. per sq. in. gage. 7. Steam Temperature. 527.6° F. (approx.) or 150° superheat. NOTES ON POWER PLANT DESIGN 163 8. Back Pressure. 17 lbs. per sq. inch absolute. 9. Capacity. The capacity of this air pump shall be at least 35 times the volume of the condensed steam. 10. Cylinders. The cylinders shall be of close-grained cast iron. The air cylinder shall be strong enough to withstand a normal working pressure of 50 lbs. per sq. in. and the steam cylinder shall be strong enough to withstand a steam pressure of 200 lbs. per sq. in. after being rebored ]/i" in diameter without causing the tensile strength in the metal to exceed 2500 lbs. per sq. in. The steam cylinder shall be lagged with 85% carbonate of magnesia held on with Russia iron covering. Provision shall be made on both the steam and air cylinders for attaching indicators. All cylinders shall be provided with drip cocks. The steam and air ports shall be of ample size to allow easy and quick action of the steam and air. All parts shall be so arranged as to be readily accessible. 11. Steam Valves and Valve Motion. Throttle valve will be furnished by the purchaser. The steam valve shall be of the balanced type with provision for taking up wear. 12. Air Valves. The air valves shall be of a suitable type for obtaining the greatest vacuum under the conditions herein specified. 13. Lubrication. Ample lubrication shall be provided for all parts subject to wear. There shall be fur- nished with pump one (1) nickle plated, 2 qt., two feed Richardson sight feed lubri- cator with divided reservoir for supplying two different kinds of oil, one for the steam cylinder and the other for the air cylinder. 14. Wrenches. One full set of wrenches shall be furnished with the pump. 15. Bolts, Etc. Bolts, nuts and screws shall be of the United States standard. 16. Finish. The working parts of the pump shall be highly finished, all exposed metal parts usually polished, such as cylinder cover and the faces of flywheels, shall be smooth turned, and together with all castings carefully filled and painted ^^ith the best quality of paint. 17. Drilling. All flanges shall be faced and drilled in accordance with Manufacturers' Standard. 18. Design, Material and Workmanship. The design shall provide ample bearing surfaces, abundant lubrication and strong ruggeil parts and shall insure safe, reliable and economical operation. The material and workmanship shall be the best of their respective kinds. The contractor shall furnish without charge f. o. b. a duplicate of any part that may prove defective in material or workmanship within one year after the pump has been started. 19. Drawings. Bidder shall submit in connection with his proposal, an outline drawing to scale and a description of the pump he proposes to furnish, giving in detail the design of pistons, plungers, valves, and arrangement made for removal of parts and for repairs. 20. Pump Data. Bidder shall furnish the following data on the pump : Dimensions : Diameter steam cylinder ins. Diameter air cylinder ins. Length of stroke ins. 164 NOTES ON POWER PLANT DESIGN Floor Space: Length ft ins. Width ft. ins. Height ft ins. Pipe Opening: Steam ins. Suction ins. Exhaust ins. Discharge ins. Steam End: Type of steam valve Area admission ports sq. ins. Area exhaust ports sq. ins. Air End: Type of air valve Area admission ports sq. ins. Area exhaust ports sq. ins. Bearings : Diameter main bearings ins. Length main bearings ins. Diameter crank pin ins. Length crank pin . ins. Diameter wrist-pin ins. Length wrist-pin ins. Diameter of shaft ins. Dimensions of cross-head shoes ins. Governor: Type of governor Flywheel: Diameter ft ins. Width of face ins. Approximate Weights: Finished weight lbs. Shipping weight lbs. SPECIFICATION FOR 1500 K. W. MAXIMUM RATED HORIZONTAL LOW PRESSURE STEAM TURBINE Steam End 1. Number Wanted. One. 2. Type. Horizontal low pressure condensing. 3. Kind of Service. Direct cormected to generator supplying current for factory motors and motor-generators or rotaries. 4. Speed. Revolutions per minute. 5. Steam Pressure at Throttle. Fifteen pounds absolute. Alternate proposition on turbine suitable to use both fifteen poimds absolute and 175 pounds per sq. in. gage. 6. Steam Temperature at Throttle. Temperature due to pressure given above. No super- heat. 7. Back Pressure. 2" of mercury absolute. 8. Regulation. The speed of the turbine shall not vary more than 23^^% above or below the normal speed at any load less than 500 K. W. Maximum speed variation where full load is thrown on or off instantaneously will not exceed %. The con- tractor shall furnish as part of the turbine an electrical synchronizing device for vary- ing the speed of the turbine from the switchboard. NOTES ON POWER PLANT DESIGN " 165 9. Capacity. When operating condensing under the condition herein stated the turbine shall furnish power to generate, — - 1500 K. W. continuously; 2000 K. W. momentarily. 10. Throttle Valve, ^he throttle valve shall be of the Schutte and Koerting make, actuated at a speed of 10% above normal by a safety governor. 11. Bolts, Nuts, Etc. Bolts, nuts and screws shall be of the United States Standard. 12. Finish. The turbine as a whole shall be highly polished, all exposed metal parts polished and castings carefully dressed down, filled and painted with the best quality of paint. 13. Drilling. All flanges shall be faced and drilled in accordance with Manufacturers' Standard for flanges and drilling. 14. Steam Consumption. The turbine shall consume not more than the amoimts of steam given below when developing the corresponding kilowatts, running at a speed of revolutions per minute, with a steam pressure of fifteen pounds absolute per sq. in. and exhausting against a back pressure of 2 inches of mercury absolute. The steam pressure shall be the averaged measured just outside the throttle valve, and the back pressure shall be measured in the exhaust pipe near the turbine. Steam Consumption Pounds per K. W. hour K. W lbs. per K. W. H. 375 lbs. per K. W. H. 750 lbs. per K. W. H. 1125 lbs. per K. W. H. 1500 lbs. per K. W. H. 15. Erection. The contractor shall provide for the superintendence of erection of the turbine, all common labor to be provided by the purchaser. The contractor agrees to have the turbine and generator erected ready for operation within 15 days after their arrival at destination provided no delays are caused by the purchaser. 16. Design, Material and Workmanship. The design shall provide ample bearing surfaces, abundant lubrication and strong rugged parts, and shall insure safe, reliable and econo- mical operation, and without undue heating or vibration. The material and workman- ship shall be the best of their respective kinds. The contractor shall furnish, without charge, f. o. b., a duplicate of any part that may prove defective in material or work- manship within one year after the turbine has been started. 17. Drawings. Bidder shall submit in connection with his proposal an outline drawing to scale and a description of the turbine he proposes to furnish, giving in detail the arrange- ments made for the removal of parts for repairs. 18. Turbine Data. Bidder shall furnish the following data on the turbine: Dimensions : Length Width Height Piping : Steam Exhaust ". Weight: Weights of heaviest part Weight of heaviest part to be moved when mak- ing ordinary repairs Shipping weight Finished weight 166 NOTES ON POWER PLANT DESIGN GENERATOR END 1. Number Wanted. One. 2. Type. Revolving field. 3. Kind op Service. Supplying current for factory motors and motor-generators or rotaries. 4. Speed. Revolutions per minute 5. Number op Poles 6. Frequency. 60 cycles per second. 7. Phase. Three phase. 8. Voltage. 480 at no load. 480 at full load, 80% power factor. 9. Regulation. The regulation of generator when operating at 100% load and 80% power factor shall not exceed %. By "regulation" is meant the rise in potential of generator when specified load at specified power factor is thrown off. 10. Capacity. The generator shall develop: 1500 K. W. continuously. 2000 K. W. momentarily. Generator shall be capable of developing K. W. as above, at voltage specified above and at any power factor not less than 80%. 11. Amperes. Full load current amperes per phase. 12. Temperature Rise. Shall not exceed the following: When generating continuously at 1500 K. W. 480 volts. 80% Power Factor. Field and armature by thermometer 50 deg. C. Collector rings and brushes by thermometer 50 deg. C. Bearings and other parts by thermometer 50 deg. C. 13. Style op Field Winding. Separately excited. 14. Excitation. Excitation of separately excited fields shall be by direct current at 125 V. It shall not be necessary to raise excitation above 125 V. in order to maintain voltage spec- ified above on the generator with 1500 K. W. load and 80% power factor. 15. Rheostat. A hand operated rheostat shall be furnished in field circuit to control the voltage. 16. Field Discharge Resistance. A suitable field discharge resistance shall be furnished. 17. Rheostat Mechanism. The generator field rheostat shall be furnished with hand wheel and chain operating mechanism suitable for mounting on switchboard panel. 18. Parallel Operation. The generator shall be designed so that it may be operated in parallel with other machines of similar type, of the same or different size, or inductive or non- inductive loads without seriously disturbing the regulation of any of the machines, or affecting the lights on the line. 19. Insulation Test. The ohmic resistance and dielectric strength of the insulation shall meet the requirements of the latest report of the Committee on Standardization of the Amer- ican Institute of Electrical Engineers. 20. Generator Data. Bidder shall furnish the following data on generator: ■ Maximum voltage that can be obtained from generator at 100% load and 80% power factor will be volts. The commercial efficiency of the generator will be as follows: % at 3^ load. % at 3/i load. % at ^ load. % at full load. Exciting current at full load and 80% power factor will be amperes at 125 volts. Maximum current on short circuit will be. amperes at unity power factor. Shipping weights will be as follows: Rotor pounds. Generator complete pounds. Heaviest piece pounds. NOTES ON POWER PLANT DESIGN 167 SPECIFICATION FOR DIRECT ACTING BOILER FEED PUMPS 1. Number. Two. 2. Type. Horizontal duplex outside packed plunger. 3. Service. Boiler feed. 4. Working Steam Pressure. 175 lbs. per sq. inch gage. 5. Working Exhaust Pressure. 17 lbs. absolute. 6. Working Discharge Water Pressure. 250 lbs. per sq. inch. . 7. Working Suction Head. 8 ft. above floor on which pump stands. 8. Temperature of Water. 212 deg. F. 9. Capacity. Normal capacity 250 gallons per minute for each pump. Maximum capacity 500 gallons per minute for each pump. 10. Water End Fittings. Hard, close-grained cast iron plungers, composition covered, bronze stuffing box glands, valve seats, and valves of the pot valve type. 11. Air Chambers of proper capacity and length to be furnished for both suction and discharge connections. 12. Proposal. Make proposal f. o. b.. .stating price; time before shipment; shipping weight; and enclose print showing general dimensions and sizes of all connections. SPECIFICATION FOR TURBINE DRIVEN CENTRIFUGAL BOILER FEED PUMPS 1. Type. Multistage Centrifugal Pumps, direct connected to Steam Turbines, on common bed plate with flexible shaft coupling. 2. Number. Two. 3. Service. Boiler Feed. 4. Maximum Capacity. 500 gallons per minute for each pump. Capacity for most economical steam consumption, — 250 gallons per minute for each pump. 5. Working Discharge Water Pressure. 250 pounds per square inch. 6. Working Suction Head above Center of Pump Shaft. 8 ft. of water. 7. Working Steam Pressure. 175 lbs. per square inch, gage. 8. Working Exhaust Pressure. 17 lbs. absolute. 9. Make Proposal f.o. b.. .stating price; time before shipment; shipping weight; print showing general dimensions and sizes of all connections; guaranteed steam consumption of tur- bine at maximum rating of 500 gallons per minute, also at 250 gallons per minute in pounds per H. P. per hour and efficiency of pump at each of above capacities. SPECIFICATION FOR AUTOMATIC PUMPS AND RECEIVERS 1. Number. Five. 2. Type. Alternate propositions on (1st) single cylinder direct acting piston type steam pump with receiver and automatic arrangement for starting and stopping pump and (2nd) horizontal duplex piston type with receiver and automatic arrangement for starting and stopping pump. 3. Service. Returning hot water drips from trap discharges, heating and curing systems, etc., to open feed water heater. 4. Working Steam Pressure. Maximum 100 per sq. inch; minimum 20 per sq. inch. 5. Working Exhaust Pressure. 17 absolute. 6. Working Discharge Water Pressure. Not over 40 ft. head including pipe friction. 7. Working Suction Head. Gravity and trap returns to receiver. 8. Temperature of Water. 150 deg. F. to 212 deg. F. 9. Capacity. Four pumps 60 gallons per minute and the fifth pump 100 gallons per minute. 168 NOTES ON POWER PLANT DESIGN 10. Water and Fittings. Three 60-gallon and one 100-gallon pumps bronze cylinder linings, piston rods, pistons, stuffing box glands, valve seats, bolts, plates and springs. Hard rubber valves for 212 deg. F. water. Water piston to have metallic packing rings and also to be arranged for the use of fibrous packing if desired. One 60-gallon pump and receiver to be iron fitted throughout, no bronze whatever. (For use with water contain- mg sulphur.) 11. Proposal. Make proposal stating price for both sizes of pumps in both single and duplex types; also 60-gallon pump and receiver iron fitted throughout; time before shipment; shipping weights; prints showing general dimensions and sizes of all connections and details of float and steam regulating valve with connections between them. SPECIFICATIONS FOR 30" x 60" x 60" HORIZONTAL CROSS-COMPOUND NON- CONDENSING CORLISS ENGINE 1. Number Wanted. One. 2. Type. Horizontal Corliss, cross-compound, non-condensing. 3. Kind of Service. Rope drive to factory line shafting. Exhausting to low pressure steam turbine. 4. Indicated Horse Power: At lowest steam consumption At maximum load 5. Speed. 80 revolutions per minute. 6. Steam Pressure at Throttle. 175 lbs. per sq. in. gauge. 7. Steam Temperature at Throttle. 377° F. 8. Back Pressure. 17 lbs. per sq. in. absolute. 9. Point of Cut-off: At lowest steam consumption % At maximum load % 10. Regulation. The speed of the engine shall not vary more than 2]/2 per cent above or below the normal speed at any load less than indicated horse power. 11. Cylinder Sizes. The dimensions of the cylinder shall be as follows : Diameter Stroke High pressure cylinder 30" 60" Low pressure cylinder 60" 60" 12. Hand. The engine shall be right hand, that is, when standing at the high pressure cylinder and looking toward the shaft, the wheel will be on the right and the low pressure cylinder on the right of the wheel. 13. Wheel. The wheel shall have 40 grooves for 1^" rope and be 18 ft. in diameter. 14. Cylinders. The cylinders shall be of close-grained cast iron strong enough to withstand 200 lbs. steam pressure per sq. in., after being rebored %" in diameter without caus- ing the tensile strength in the metal to exceed 3500 lbs. per sq. in. It shall be lagged with 85% carbonate of magnesia held on with Russia iron covering. Provision shall be made on the cylinder for attaching indicators, and an indicator re- ducing motion shall be provided as part of the engine. The cylinder shall be provided with drip cocks. The steam ports shall be of ample size to allow easy and quick action of the steam. • 15. Valves. The cylinder shall be provided with relief valves of ample size and at suitable position to protect the engine from damage due to water. Throttle valve shall be furnished with the engine. The steam valves shall be of the Corliss type with separate eccentrics for the steam and exhaust valves. NOTES ON POWER PLANT DESIGN 169 16. Governors. The governor for the engine shall be of the flyball type. 17. Lubrication. Lubrication shall be by means of sight feed oil cups which shall be accessibly located and shall positively and continuously supply the main shaft bearings, crank pins, wrist pins, guides, valve parts, etc. with oil. These oil cups shall be provided with bottom connections piped to a common point ready for connection to a gravity oiling system. All pipe shall be semi-annealed iron pipe size brass pipe. All brass parts shall be polished and nickel plated. Grease cups will be allowed only on eccentrics. Two Richardson model "M" four-feed oil pumps shall be furnished for the cylinders. 18. Wrenches and Drawings. The following fittings shall be furnished with the engine: 1 set of forged steel wrenches. Foundation plans for setting foundation bolts. , Drawings showing dimensions of engine and foundation. 19. Packing. The piston rod shall be packed with metallic packing and the valve stems with metallic packing. 20. Bolts, Etc. Bolts, nuts and screws shall be of the United States standard. 21. Finish. The engine as a whole shall be highly finished, all exposed metal parts polished and castings carefully dressed down, filled and painted with the best quality of paint. 22. Drilling. All flanges shall be faced and drilled in accordance with Manufacturer's Standard. 23. Steam Consumption. The engine shall consume not more than the amounts of steam shown below for each load when running at a speed of 80 revolutions per minute with a steam pressure of 175 lbs. per sq. inch above the atmosphere at a temperature as indicated below and exhausting against a back pressure of 17 lbs. per sq. inch absolute. The steam pres- sure shall be the average measured just outside the throttle valve and the back pressure shall be measured in the exhaust pipe near the engine. Steam Consumption in Pounds per I. H. P. Load I. H. P. Saturated Steam M Full 24. Erection. The engine shall be erected by the Contractor on foundation furnished by the Purchaser. After the engine arrives at destination the Contractor agrees to push the erection through with all reasonable promptness, working a full day force. The engine is to be erected ready for operation within 30 days after its arrival at destination. 25. Design, Material and Workmanship. The design shall provide ample bearing surfaces, abundant lubrication and strong rugged parts and shall insure safe, reliable and econo- mical operation, and without undue heating or vibration. The material and workmanship shall be the best of their respective kinds. The Contractor shall furnish, without charge, f . o. b a duplicate of any part that may prove defective in material or workmanship within one year after the engine has been started. All nuts on cylinder heads, bonnets and other parts which are subject to re- moval shall be case-hardened. All connections about the engine shall be made perfectly tight and all parts of the engine made as accessible as possible and capable of ready removal for repair or replacement. All parts of the engine subject to wear shall have means provided for taking up such wear. All interchangeable parts shall be machined to gauge. 26. Drawings and Data. Bidder shall submit in connection with his proposal an outline drawing to scale and a description of the engine he proposes to furnish, giving in detail the design of cylinder, piston, governor, bearings and arrangement made for removal of parts and for repairs. 170 NOTES ON POWER PLANT DESIGN 27. Engine Data. Bidder shall furnish the following data on the engine: Floor Space Length ft inches Width ft inches Height ft inches Piping H. P. Cyl. L. P. Cyl. Steam inches Exhaust inches Valves Type of steam valves " Area admission ports sq. in. Area exhaust ports sq. in. Connecting Rods Type Length inches Bearings Diameter main bearings Length main bearings L.P. L.P. L.P. L.P. Diameter crank pin H.P. ... Length crank pin H.P. ... Diameter wrist pin H.P. ... Length wrist pin H.P. ... Diameter of shaft Dimensions of cross- head shoes . Governor Type of governor Belt Wheel Diameter 18 ft. inches Width of face 56 inches Weights Weight of heaviest part lbs. Weight of fly-wheel lbs. Shipping weight of engine lbs. Finished weight of engine lbs. NOTICE TO CONTRACTORS Steam Driven Centrifugal Pumping Unit for the City of. Sealed proposals and bids for furnishing to the City of Mass., and installing in the St., Pumping Station of the City of a steam turbine driven centrifugal pumping outfit, as hereinafter described, will be received by the Commission of Water and Water Works of at the City Hall, Mass., until 12m, September , 1913. Bids must be made in duplicate. Each bidder must leave with his bid a properly certified check for the sum of two thousand dollars ($2,000) payable to the order of the City of , which check will be returned to the bidder unless forfeited as hereinafter provided. A bond will be required, for the faithful performance of the contract, in the sum of ten thousand dollars ($10,000) of an approved surety company doing business in Massachusetts. The bidder is requested to name the surety company which will sign his bond in case the con- tract is awarded him. NOTES ON POWER PLANT DESIGN 171 If notice of the acceptance of the bid shall, within twenty days after September , 1913, be given to the bidder by the Commissioner of Water and Water Works of , the bond must be fm'nished within six days (Sunday excepted) after such notification; and in case of the failure of the bidder after such notification to furnish the bond within said time the bid shall be considered as abandoned and the certified check accompanying the bid shall be for- feited to the city. Each bidder is to furnish with his bid detailed description and specifications covering the appar- atus he purposes to install. He is to give also the duties (duty is here considered as the foot-pounds of water work done per million British Thermal Units) he will guarantee. First considering the steam used by the steam turbine alone without including the steam used by either wet or dry pumps used in connection with the condensing outfit, and Second including the steam used by these pumps with the turbine steam. The guarantees of duty to be made on a pressure at the throttle of 125 lbs. gage and on steam containing not more than one and one-half per cent moisture. The temperature of the returns to the boiler to be taken the same as the temperature of the condensed steam leaving the condenser. If the exhaust steam from the wet and dry pumps is sent through a feed water heater and used to heat the 'steam condensed from the turbine on its way to the boiler, the temperature of the returns will be taken as the temperature of this feed water. The temperature of the suction water to be taken at 70°. The conditions as to head and capacity to be taken as hereinafter outlined. Each bidder is to furnish dimensioned drawings giving the general outside measurements of the entire apparatus when assembled together with such drawings or cuts as may be necessary to show the construction of his apparatus. The one to whom the contract is awarded is to furnish the city with a working drawing of the foundation (to be built by the City) and complete working drawings of the turbine centri- fugal pumps and condensing outfit complete. The bidder is to guarantee that all bearings and reduction gears if used will be continuously lubricated and will run continuously without over-heating. The bidder is to agree to make at his own expense all repairs which may be made necessary through original faulty construction, design or workmanship for a period of six months after the unit goes into regular service. Neither experimental nor unusual types of apparatus will be considered. Each bidder must be prepared to prove to the satisfaction of the Commissioner that he has previously installed units of the type he purposes to furnish and he shall state where such units are in successful operation. The bidder must state the general type design and builders name of any part of the unit which is not built at the works of his own company. The bidder must give the date of delivery and the time required for the erection of the com- pleted plant. Payments will be made as follows : Fifty per cent of the contract price ten days after the de- livery of the turbine, pumps, condensers, and accessories at the pumping station and the balance due the contractor ten days after the acceptance of the unit by the City. The Commissioner reserves the right to reject any or all bids or to award the contract as he deems best. The duty guaranteed, the general design and accessibility of the parts, together with the cost, will be considered in awarding this contract. Bids in which the duty guaranteed per 1,000,000 British Thermal Units including the steam used by the condensing apparatus, falls below 92,000,000 foot-pounds will not be considered. The bidder will submit his bid and his specifications on his own printed forms and will add to the same the following: The Contractor will indemnify and save harmless the City from all claims against the City by mechanics, laborers, and others, for work performed or materials furnished for carrying on the contract. The Contractor will indemnify and save harmless the City, its agents and employees, from all 172 NOTES ON POWER PLANT DESIGN suits and claims against it or them, or any of them, for damages to private corporations and indi- viduals caused by the construction of the work to be done under this contract; or for the use of any invention, patent, or patent right, material, labor or implement by the contractor, or from any act, omission or neglect by him, his agents, or employees, in carrying on the work; and the Con- tractor agrees that so much of the money due to him under this contract as may be considered necessary by the Comtnissioner may be retained by the City until all such suits or claims for damages as aforesaid shall have been settled and evidence to that effect furnished to the Commissioner. The Contractor agrees to do such extra work as may be ordered in writing by the Commis- sioner, and to receive in payment for the same its reasonable cost as estimated by the Commis- sioner plus fifteen per cent of said estimated cost. The Contractor agrees to make no claims for compensation for extra work unless the same is ordered in writing by the Commissioner. The Contractor still further agrees that the Commissioner may make alterations in the work, provided that if such changes increase the cost, the contractor shall be fairly remunerated and in case they diminish the cost the proper deduction from the contract price shall be made — the amount to be paid or deducted to be determined by the Commissioner. General Description of Pumping Unit A steam driven turbine either directly connected to a centrifugal pump or connected through reduction gears and having a smaller stage centrifugal connected by friction clutch or other suit- able device to the end of the pump shaft or to one end of the turbine shaft all mounted on a suit- able bed plate is to be installed together with a water works type condenser and necessary wet and dry pumps in the St. Pumping Station of the City of A feed water heater using the exhaust steam of the wet and dry pumps may be installed by the contractor (the one to whom the contract is awarded is hereinafter designated as the Contractor) if hereby he is able to increase the duty by raising the temperature of the returns. This equipment is to be put in the ell at the back of the building which ell is now used as _a coal pocket and storage room. There is now a large outside door at the end of the ell leading from the back yard into the basement of this building. Another large door located over this basement door at the level of the present engine room floor is to be made by the city. The turbine will have to be taken in through this new door and the condensing equipment through the basement door. This outfit is to be erected and installed by the Contractor on a foundation built by the City in accordance with drawings furnished by the Contractor. (Foundation bolts are to be furnished by the Contractor.) The Contractor is to temporarily strengthen any floors, coal pockets, etc. he may move his machinery over and to take all responsibility during the erection of the machinery. Under no circumstances is the operation of the pumping station to be interfered with. The City will bring steam to the throttle of the turbine. The throttle valve and safety throttle are to be furnished and erected by the Contractor. The City will connect the "suction" pipe with the intake of the condenser and will make all connections to the force mains back to the discharge end of the centrifugals. In preparation for tests of this unit the City will install a Venturi meter in each of these force mains. The Contractor is to pipe the condensed steam back to the boiler feeding apparatus and to make all other connections, not specifically referred to. The Contractor is to provide, connect, and put in place suitable 8}^" polished brass gages with gage cocks as follows, all mounted on a gage board of mahogany or stone fastened to the wall of the room at some point to be designated by the chief engineer of the station. Gage for pressure at throttle to be divided to 150 lbs. by one pound marks. Gage pressure in condenser: this to be a combination pressure and vacuum: 20 lbs. pressure. Gage for measuring pressure in force mains of large centrifugal: 120 lbs. by 1 pound marks. Gage for measuring pressure in force mains of small centrifugal: 150 lbs. by 1 lb. marks. Gage for showing pressure of water at intake to condenser: 50 lbs. by 1 pound marks. A clock in a case like the gages is to be fm-nished by the Contractor and mounted on this gage board. The Contractor is also to provide, connect, and put in place, a mercviry column for measuring the vacuum in the condenser and thermometers m suitable wells for determining the temperature NOTES ON POWER PLANT DESIGN 173 of the water entering the condensers, the temperature in each force main and the temperature of the returns from the condenser to feed pumps. Water comes to these pumps at what has been called the "suction" side under a static head of about 23 feet, the head depending upon the level in Breed's Pond. In making calculations for duty an average value of the static head of 23 feet at the level of the main floor in the present sta- tion may be assumed. The pipe leading from Breed's Pond to the Street Station is about one-half mile in length and is 36" in diameter for the first third of the distance and 30" for the remaining two-thirds of the distance. There are four elbows in this 30" line. The centrifugal directly connected or connected through reduction gears to the turbine shaft is to discharge 13,000,000 U. S. gallons in 24 hours into a 30" force main about one-half mile long ■ — practically a straight run of pipe. The static pressure at the level of the station floor of the main station is 60 lbs. The present pumping outfit is discharging water through this pipe at the rate of 10,000,000 gallons in 24 hours. The stage centrifugal, connected to the turbine shaft or pump shaft by a friction clutch or other suitable device is to deliver 2,000,000 U. S. gallons in 24 hours to a stand pipe through about one- half mile of pipe; the first half of which is 16" diameter and the last half 12" diameter; all of cast iron. The static pressure at the level of the station floor of the main station is 105 lbs. Drawings of the pipe lines can be seen at the office of the City Engineer, City Hall, , Mass. The two pumps will be run together the greater part of the time, the high pressure pump con- nected and disconnected by means of a clutch or other suitable device without stopping the turbine. The water coming from Breed's Pond to the Street Station varies in tem- perature from 35° to 80°. A temperature of 70 degrees seems a fair average. The boilers now installed are to furnish the steam for this unit. These boilers are of the horizontal Multitubular type; two in number working at 125 lb. gage. The steam from these boilers may be considered to contain not more than 13^ per cent moisture. The condenser is to be made strong enough to stand with safety 105 lb. gage pressure on the water side and 20 lb. gage pressure on the steam side. A 2" safety valve with whistle is to be attached to the steam side of the condenser. The turbine is to be provided with a safety throttle quick operating trip or other suitable device, satisfactory to the commissioner to prevent speeding. The turbine is to be provided with an outboard exhaust through a water sealed automatic relief valve. The discharge from this valve to be carried by means of spiral riveted pipe through the roof. The opening made in the roof for this pipe is to be properly flashed with copper and made tight against rain and snow. To allow for expansion there is to be a flexible connection in the piping between the turbine and the condenser. The pump impellers are to be of bronze on suitable non-corrosive material and unbalanced end thrust on the impellers to be avoided as far as is possible. The impeller shafts are to be protected from corrosion by removable sleeves of composition. Composition packing glands and bronze studs are to be provided for the pumps. The contractor is to paint all machinery and piping erected by him. Such castings as are in sight from the floor of the engine room are to be made smooth, nicely fitted at all joints and flanges, filled with a proper paint filler and painted and striped in such colors as the commissioner may direct. The Contractor is to remove all blocking, tools or other material used by him in erecting and installing his work and to remove all debris of any nature, in and around the Street Pumping Station, produced by him in carrying out this contract. 174 NOTES ON POWER PLANT DESIGN SPECIFICATIONS FOR AND DESCRIPTION OF PUMPING UNIT FOR Location. The pumping unit is to be installed in a new building distant about 500 feet north from the pumping station on Pond now supplying the City of Floor Level. The building will be located on the shore of the pond. The pump room floor being from 4 to 7 feet above the level of full pond. Pump Motor. The pump is to be either a single or two stage centrifugal, driven by a 4000 volt three phase, 60 cycle alternating current motor of the external resistance, slip ring type com- plete with device for lifting brushes and short circuiting rings after the pump is up to speed, and all necessary starting equipment. Motor. The motor must be so designed that the starting current, under given load, will not exceed full load running current. Motor Characteristics. The temperature rise of the motor when operating at normal rating with a room temperature of 25° C. is not to exceed 40° C. Electrical Switchboard. A switchboard of slate with dull black finish with the following equipment is to be furnished and erected, all meters in black finish. (1) One voltmeter with scale calibrated to show 4000 volts. (2) One indicating watt meter. (3) One ammeter with switch to show current on any of the three phases. (4) One kilowatt hour meter. (5) Suitable testing terminals to enable check to be made on these instruments. (6) Available space for the instruments of the Electric Light Co. which will be one kilowatt hour meter and suitable testing terminals. (7) Complete switch-operating mechanism and mounting for all switches necessary for starting and controlling the motor. The oil circuit breaker to be of remote mechanical control type. (8) Necessary current and potential transformers for preceding equipment; also available space and mounting for the necessary current and potential transformers fur- nished by the Electric Light Co. (9) A 125-volt switch to control electrically operated discharge valve if such electrically operated valve is used; provision shall also be made for 125 volt lighting. Lightning Protective Apparatus. In addition to the preceding the following are to be fur- nished and separately mounted: One complete lightning arrester and choke coil outfit for one 3-phase 4000 volt circuit, (Y connected, neutral grounded at generating plant only, through low resistance); also suitable disconnecting switches for the lightning arresters and incoming circuit respectively. Circuit Breaker. One oil circuit breaker with inverse time limit overload relay and no-voltage release, with remote mechanical control. Bus Work and Wiring. All bus work and wiring necessary .for connecting the motor to the switchboard and to power wires on the outer wall of the pump house, consisting of copper conductors, clamps, insulators, pins and pipe frame-work and other details necessary for the successful operating of the equipment, are to be furnished and installed by the contractor. Power wires o*utside of the pump house are to be installed by the Electric Light Co. Pump Capacity. The centrifugal pump is to discharge 8,000,000 U. S. gallons in 24 hours from a pump well with water at grade 127, through about 2180 feet of new 36" cast iron pipe to a standpipe with water at grade 305. There is to be a hydraulically or an electrically operated valve and a check valve between the pump and the 36" main. These valves are to be fur- nished and installed by the city. Head. This 36" pipe will receive an additional 8,000,000 gallons in 24 hours from a second unit in the same pumping station or from another station approximately 500 feet away. This fact is to be noted in considering the total head the pump is to work against. Impeller End Thrust. The pump impeller is to be of bronze or suitable non-corrosive material, and unbalanced end thrust on the impeller is to be avoided as far as possible. The pump NOTES ON POWER PLANT DESIGN 175 impeller and the pump casing shall be provided with bronze renewable wearing rings so that they may be readily replaced if necessary. Impeller Shafts. The impeller shafts are to be protected from corrosion by removable sleeves of composition. Composition packing glands and bronze studs are to be provided for the pumps ; stuffing boxes on ends of pump shall be provided with water seals. Priming Device. The pump is to have a water ejector or other device capable of removing air from the pump, in priming, in a period of five minutes. Discharge Valve. A hydraulically or electrically operated valve in the discharge pipe of the pump and not over 20 feet from the discharge outlet of the pump will be installed by the City and all necessary pipmg, valves or wiring and switches needed for the operation of this valve are to be furnished and connected up by the contractor. This valve will be closed with the pump running at full speed preparatory to shutting down the unit. Pump Characteristics. The Contractor must submit with his bid curves showing the char- acteristics of the pump he proposes to furnish. He must guarantee also the efficiency of his pump at 8,000,000 gallons capacity when working under the total head (previously explained) . The pump shall be carefully tested before it leaves the manufacturer's shop to show that the efficiency guaranteed has been obtained. A certified test shall be submitted for the approval of the Water Board before shipment is made and notice 10 days previous to test shall be sent to the Water Board so that it may be present if it desires. Should the efficiency of the purnp as determined by the test fall below that guaranteed, the Water Board may reject the pump or at its option may accept the pump at such reduction in the original contract price as the city of may suffer in monetary loss during a period of eight years -through the lower efficiency. The Contractor shall furnish the Water Board with the necessary facili- ties for carefully inspecting the apparatus during the process of manufacture. Foundation. The foundation for the imit will be erected by the city in accordance with draw- ings to be furnished by the contractor. The contractor is to supply all foundation bolts and plates. The Contractor is to furnish, erect and connect the unit complete up to the discharge flange of the pump; also to make necessary and suitable connections for the opera- tion of the hydraulically or electrically controlled valve in the discharge pipe. AuxiLLVRY Apparatus. The Contractor is to furnish, erect, wire up and make all necessary cormections to such auxiliary apparatus as may be required for the quick and successful oper- ation of his unit. Wrenches. The Contractor is to furnish all special wrenches or tools required in assembling or in dismantling either the pump or the motor. Gages and Panel. The Contractor to provide a slate panel, dull black finish, matching the electrical board and mounted alongside same, containing the following: A seven day clock mounted in a brass gage case, black finish; a 10" dial brass mounted suction gage and a 10" dial brass mounted delivery gage, — these being connected to the suction and delivery pipes respectively. These gages to be marked in feet, pounds, or inches of mercury as may be re- quested by the Water Board, and the cases given a black finish. Painting. The Contractor is to paint all machinery and piping erected by him. Such castings as are in sight from the floor of the pump room are to be made smooth, nicely fitted at all joints and flanges, filled with a proper paint filler and painted and striped in such colors as the Water Board may direct. Debris. The Contractor is to remove all blocking, tools or other material used by him in erect- ing and installing his work and to remove all debris of any nature in and around the pumping station, produced by him in carrying out this contract, at least 100 feet from station or to such place as he may be directed. Bids. Bids must be made in duplicate. Each bidder must leave with his bid a properly certi- fied check for the sum of two thousand dollars ($2000) payable to the order of the City of , which check will be returned to the bidder unless forfeited as hereinafter provided. Bond. A bond will be required for the faithful performance of the contract in the sum of 50% of the contract price with a surety company approved by the mayor. 176 NOTES ON POWER PLANT DESIGN The bidder is requested to name the surety company which will sign this bond in case the contract is awarded him. If notice of the acceptance of the bid shall, within twenty days after June 20th, 1914, be given to the bidder by the Water Board, the bond must be furnished within ten days (Sunday excepted) after such notification; and in case of the failure of the bidder after such notification to furnish the bond within said time the bid may be considered as aban- doned and the certified check accompanying the bid may be forfeited to the City. Description. Each bidder is to furnish with his bid detailed description and specifications cover- ing the apparatus he purposes to install. Drawings. Each bidder is to furnish dimensioned drawings giving the general outside measure- ments of the entire apparatus when assembled together with such drawings or cuts as may be necessary to show the construction of his apparatus. Weights. The individual weights of the rotor, stator and pump are to be given and photographs of typical equipment or design proposed should be furnished if possible. Wiring. The bidder is to attach to his proposal wiring diagrams and detail drawings of the switch- board and power wiring. Motor Performance. The bidder is to furnish guarantee as to motor performance when operat- ing under the following conditions : (1) Speed regulation when operating between no load and full load, stating load at which motor is rated. (2) Power factor at 25, 50, 75, 100 and 125 per cent load. (3) Momentary overload, per cent which motor will carry safely. (4) Efficiency based on room temperature of 25° C. at the following percentages of load: (Respective ultimate temperatures used in the calculation of each case, to be stated) . 25, 50, 75, 100 and 125 per cent load. (5) Torque: Give pull out and starting torque in terms of full load torque. (6) Temperature rise at 125 per cent normal rating for two hours following a run at normal rating of sufficient length to enable the motor to attain a constant temperature. ■ (7) Certified tests covering the preceding to be furnished by the party to whom the con- tract is awarded before the apparatus leaves the manufacturer's shop. Shipment not to be made until approved by the Water Board. Test sheets are to be accompanied by a description of the method of test, which should as far as possible be in accordance with the Standardization Rules of the American Institute of Electrical Engineers. If doubt arises that the unit has not corne up to test the Water Board reserves the right to conduct another test after the installation; the party in error being responsible for payment of expenses of test. Bearings. The bidder is to guarantee that all bearings will be continuously lubricated and will run continuously without overheating. Repairs. The bidder is to agree to make all repairs which may be made necessary through original faulty construction, design or workmanship, for a period of one year after the unit goes into regular service, at his own expense. Neither experimental nor unusual types of apparatus will be considered. Units Previously Installed. Each bidder must be prepared to prove to the satisfaction of the Water Board that he has previously installed units of the type he pro- poses to furnish and he shall state where such units are in successful operation. The bidder must state the general type, design and builder's name, of any part of the unit which is not built at the works of his own company. Delivery. The bidder must give the date of delivery and the time required for the erection of the completed plant. Payments. Payments will be made as follows: One-third of the contract price ten days after the delivery of the motor, pump and accessories; one-third within thirty days after satis- factory and successful operation; one-third thirty days after the acceptance of the unit by the city. Acceptance. The '.Water Board reserves the right to reject any or all bids or to award the contract as it deems best. NOTES ON POWER PLANT DESIGN 177 The general design and accessibility of the parts, together with the cost will be consid- ered in awarding this contract. Bidder to Add to his Specifications. The bidder will submit his bid and his specifications on his own printed forms and will add to the same the following: That he will indemnify and save harmless the city from all claims against the city, mechan- ics, laborers, and others for work performed or material furnished for carrying on the contract. That he will indemnify and save harmless the city, its agents and employees, from all suits and claims against it or them or any of them, for damage to private corporations and individuals caused by the construction of the work to be done under this contract; or for the use of any invention, patent, or patent right, material, labor or implement by the contractor or from any act, omission or neglect by him, his agents, or employees, in carrying on the work; and that he agrees that so much of the money due to him under this contract as may be con- sidered necessary by the Water Board may be retained by the city until all suits or claims for damages as aforesaid shall have been settled and evidence to that effect furnished to the Water Board. The successful bidder will be required to furnish a certificate to the Water Board certifying that the men employed by him on the work herein set forth are insured under the provision of the Workmen's Compensation Act, so-called, of Massachusetts. That he agrees to do such extra work as may be ordered in writing by the Water Board, and to receive in payment for same its reasonable cost as estimated by the Water Board plus fifteen per cent of said estimated cost. That he agrees to make no claim for compensation for extra work unless the same is ordered in writing by the Water Board. And that he still further agrees that the Water Board may make altera- tions in the work provided that if such changes increase the cost he shall be fairly remunerated and in case they diminish the cost, the proper reduction from the contract price shall be made, — the amount to be paid or deducted to be determined by the Water Board. MASSACHUSETTS INSTITUTE OF TECHNOLOGY Coal Supply — 1914-1915 The Massachusetts Institute of Technology invites your bid on its supply of coal for the forth- coming fiscal year, July 1, 1914-July 1, 1915, on the following terms: (1) Delivery Daily, as called for, at 491 Boylston St., rear of 26 Trinity Place, Garrison St., and else- where, if desired, at the Technology buildings. (2) Kinds and Amounts (a) No. 2 Buckwheat, 2700 tons, more or less (b) Semi-bituminous, 3800 tons, more or less (3) Specifications (a) No. 2 Buckwheat — free from dust. (b) Semi-bituminous — of good steaming quality. The coal offered should be specified in terms of moisture "as received," ash, volatile matter, sulphur and B. T. U., "dry coal" basis, which values become the standards for the coal of the successful bidder. The trade name of the coal should be given. (4) Prices and Payments (a) No. 2 Buckwheat — payments monthly at price named. (b) Semi-bituminous — payments monthly on the basis of price named in bid, corrected for variations as to heat value, ash and moisture above or below, as follows: Heat Value — On a "dry coal" basis, no adjustment in price will be made for variations of 1% or less in the number of B. T. U.'s from the guaranteed standard. When such varia- tions exceed 1%, the adjustment will be proportional and determined as follows: B. T. U. delivered coal, "dry" ^.^ . B.T.U. specified in bid "" ^'^ P^^^" = '"^^^^^^S pnce. 178 NOTES ON POWER PLANT DESIGN Ash — On a "dry coal" basis, no adjustment in price will be made for variations of 1% or less above or below the per cent of ash guaranteed. When such variation exceeds 1%, the adjustment in price will be determined as follows: The difference between the ash content of analysis and the ash content guaranteed will be divided by 2 and the quotient multiplied by bid price, the result to be added to or subsracted from the B. T. U. adjusted price or the bid price, if there is no B. T. U. adjustment, according to whether the ash content by analysis is below or above the per- centage guaranteed. Moisture — The price will be further adjusted for moisture content in excess of amount guaranteed, the deduction being determined by multiplying the price bid by the percentage of moisture in excess of the amount guaranteed. (5) Sampling and Testing The samples of coal shall be taken by the Institute or its representative and no other sample will be recognized. The coal dealer or his representative may witness the operation of the sampling if so deptred. Samples of the coal delivered will be taken by the Institute or its representative from the wagons while being unloaded. Two or more shovelfuls of coal shall be taken from each wagon load and placed in a metal receptacle under lock. Not less than three times in any one month the samples, thus accimiulated, shall be thoroughly mixed and quartered in the usual manner. The final sample is to be pulverized and passed through an 80-mesh sieve. A part of the final sample shall be put aside in an air-tight jar properly marked, for the coal dealer, so that he may verify results if he so desires. The coal shall be dried for one hour in dry air at a temperature between 104° C. and 105° C. The coal shall be tested by the Institute, a bomb calorimeter being used. Should the coal dealer question the results, a sufiicient quantity of the original sample is to be furnished him for testing if he so requests it. The average of the results of the tests made each month shall be the basis for determining the price to be paid for coal delivered during that month. (6) Limits Should the heating value per pound of dry coal fall below 14,500 B. T. U., or should the moisture exceed 3%, or the ash exceed 7%, or the sulphur 1%, or the volatile matter 20%, the agreement may be terminated at the option of the Institute. (7) The Right to reject any or all bids is reserved by the Institute. Cross- Secfic Thc Engincerinq T tfPft Rft z »a« H < -n H s CO :2 z o G H > M < > C o > -1 O Oh u > J^ -1 < z o > 2 Q '5 U (73 < C c ^ J a. C/5 ^ NH o o z 6 ^sM#^-?-j^s;5ps|^ ^^S m^ ^ ^ff f £ 11 1 * JM Ir SECTIONAL ELEVATION OF PORT MORRIS STATION. — eoston Edison L Street Power-House. -Lots Road, Chelsea : Sectional Elevation. ,. — Quincy Point Power- House: Elevatioa LbAp'16 K LIBRARY OF CONGRESS 021 213 123 4