Steam:
Its Generation and Use

Comparative Test, made at the station of the Brush Electric Light Co., Philadelphia, between the Babcock & Wil- cox and Return Tubular boilers, by J. C. Hoad- ley, on the part of the Babcock & Wilcox Co., and W. Barnet Le Van, on the part of the Brush Electric Light Co., October, 1882, the conditions as to quality of coal and management of fires being much in favor of the return tubular boilers, as was certified to by both experts. This state- ment and full data and details of calculation were published in Van NostrancPs Magazine, 1883, copy of which will he furnished on application. 1. Test by Evaporation of Water. Points Observed. Babcock & Wilcox. Return Tubular. Date of test Oct. 18, It), 20. 21.5 hours Oct. 23, 24, 25. Duration of test 16 hours. Quality of coal (anthracite Wet and dirty Screened Chestnut) and dry. Coäl thrown on grate Surface water in coal lbs. 16,388.5 “ 1,207.8 “ 15,180.7 “ 462 is.vj-s 378 Dry coal thrown on grate.. 12,793-5 Wood used for kindling... 319 Cotton waste, to start fires. 72-5 34-5 Ashes and residue Combustible (in coal) con- “ 3,305 2,697 sumed “ 11,875-7 10,096.5 Combustible =wood xo.36. “ 166.3 “5 Combustible = cotton waste Total combustible con- “ 73-S 34-5 sumed “ ’2,114.5 134,410,015 10,246 Heat units apparently re- ceived by boiler 106,300,397 Heat units actually received — water allowed for Heat units received per 1 lb. 130,176,100 104,110,609 of combustible Water evaporated from and at 2120 F. per 1 lb. com- 10,745.48 10,161.1 bustible lbs. 11.127 10.522 Apparent efficiency, per ct. Heat units required to dry 74.18 yo-'S 482,555 the coal Water evaporated from and 1,497.793 at 2120 F. per 1 lb. of com- bustible expended in dry ing the coal, lbs. Water actually evaporated 0.128 0.049 from and at 212° F. per 1 lb. of combustible 11.255 10.571 Actual efficiency, per cent. 75.03 70.47 of theoretical Comparative Economy by the Evaporative Test: 11.255— IP*S7I 0*684 ; and ——~ 0.0647 6.47 per cent. 2, Test by Power Developed Through Engines. Points Observed. Babcock & Wilcox. Return Tubular. Mean indicated horse-power 130.41 I37-78 Duration of experiments as above hours ai-5 16 Combustible consumed lbs. 12,114-5 10,246 Combustible consumed per hour 563.46 64o-375 Combustible consumed per H. P. per hour 4.321 4.648 Water evaporated 130,156 104,562 Water evaporated per hour... Water evaporated per H. I*, per hour 6,054 6,535 46.57 47-43 Dry steam per H. I’, per hr.. 45 1 46-45 Leakage per H, P. her hour.. >o-43 12.33 Dry steam used per H. P. per hour 34-67 34-12 Comparative Economy by the Engine Test: , 0.327 _ __ 4.648 — 4*321 = 0.327; and ---------- = 0.0757 = 7.57 per cent. 4.321 3. Test by Waste Heat in Chimney. Character of Waste. Babcock & Wilcox. Parts in 100. Return Tubular. Parts in 100. Loss of heat carried off by heated gases in chimney. Loss by imperfect combus- tion, and radiation Aggregate losses Actual efficiency by evapor- ative test Total heating power of combustible 20.54 4-43 25-47 4.06 24.97 75.03 29-53 70.47 100.00 100.00 Loss carried off by hot gases, Ret. Tub. boilers. .25.47 Pr- ct- Loss carried off by hot gases, B. & W. boilers.. .20.54 Pr- ct- Difference ; greater loss by Ret. Tub. boilers.... 4.93 pr. ct. This difference, or excess of heat lost by the Return Tubular boilers, divided by the effi- ciency of these boilers (70.47 per cent.), gives the ratio of the excess of loss to actual efficiency : —- = 0.06996 = 7.00 per cent. 70-47 4. Test by Light. Points Observed. Babcock & Wilcox. Return Tubular. 1. Indicated horse-power, mean of all tests 130.41 137.78 2. Hours run 21-5 16 3. No. of arc lights run... 121 128.75 4. Average H. P. per light. 1-0703 I.0701 5. Pounds of combustible per light per hour 4-6567 4-0738 Comparative Economy by the Light Test: 0-3171 4.9738 — 4.6567 = 0.3171 ; and--*= 0.0681 = 6.81 per cent. 4 6567 4. Summary of Results by the Four Methods. Tests. Babcock & Wilcox. Return Tubular. Difference in favor of B. & W. Boilers. Difference per centum. Evaporative test ”•254 10.570 .684 6-47 Power, engine test 4-321 4.648 ■327 7-57 Light test 4•6567 4-9738 •3I71 6.81 Test by loss at chimney.. 20.54 25-44 4-9 7.00 Mean of four tests 6.96 Explanation of Table.—The Babcock & Wil- cox boilers evaporated more water for each pound of combustible consumed; consumed less combustible per hour for each indicated H.P. produced, consumed/^ combustible per hour for each arc light in use; and lost less heat by hot gases escaping to the chimney, than the Re- turn Tubular boilers. While doing this, they were evaporating 6054 pounds of water per hour, into steam, containing 87