Pocketbook of Useful Formulæ and Memoranda
for Civil and Mechanical Engineers

493 OF ENGINEERING FOBMULÆ. FEED-WATER. C = Cubic contents of cylinder and of one steam passage. c = Cubic contents of displacement of pump- plunger. S = Specific volume of steam (varying with the pressure), see Table, “ Specific Volume.” 4G Approximately about -07 cube foot, or nearly A gallon per nominal horse-power per minute for condensing stationary engines. Feed-wateb in Expansive Engines. A = Area of piston in inches. S = Stroke of engine in feet. R = Number of revolutions per minute. x' = Ratio of admission of steam; stroke being = 1. v — Specific volume of steam corresponding to the, pressure of ateam on admission to the cylinder. Q = Cubic feet of steam consumed per hour, allowing for loss in passages, piston clearance, leakage, &c. q = Cubic feet of water to be evaporated per hour. Q = 1-05 ASRar; q = - • V Fire-grate area in Cornish or Lancashire boilers about = ‘72 q.