Pocketbook of Useful Formulæ and Memoranda
for Civil and Mechanical Engineers

468 Molesworth’s pocket-book “Fbench" or “Elephant” Boiler. (See ‘ Trans. Inst. Civ. Eng.,’ vol. xlii.) D = Diameter of boiler in feet. <Z = Diameter of heater in feet = • 6 D. L = Mean length of the boiler and heaters. H = Nominal horse-power at 16’9 square feet per HP. n = Number of heaters. S — Heating surface in square feet. No. of heaters. 0 1 2 n S = 16'1H; S = 8-05 II + 8'05 H; S = 5-37 H + 10-73H; 161H 16-lHn. ~ n + 1 + n + 1 ’ 10-75H D~' 5-38H L=—p — _ 3’58 H T - 10-7511 ~ b(n + 1) The heating surface of the heater is assumed at |ths of the circumference, that of the boiler and with the proportion of <Z — *6 I), the heating surfaces of boiler and heater will be equal per unit of length. Maximum diameter of boiler = 4 feet. „ „ heater = 2 feet 3 inches. Minimum diameter of heater = 1 foot 6 inches.