Where W = the weight of steam discharged in pounds per minute,
A = area of orifice in square inches,
P = the absolute initial pressure in pounds per square inch,
d = the difference in pressure between the two sides in pounds
per square inch,
K = a constant = .93 for a short pipe, and .63 for a hole in a
thin plate or a safety valve.
[Illustration: Vesta Coal Co., California, Pa., Operating at this Plant
3160 Horse Power of Babcock & Wilcox Boilers]