For steam flowing through an orifice from a higher to a lower pressure where the lower pressure is greater than 58 per cent of the higher, the flow per minute may be calculated from the formula:

W = 1.9 A K( (P - d ) d ) ( 50 )
WhereW=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=
[Pg 322] a constant = .93 for a short pipe, and .63 for a hole in a thin plate or a safety valve.

Vesta Coal Co., California, Pa., Operating at this Plant 3160 Horse Power of Babcock & Wilcox Boilers

FOOTNOTES

[ [80] ] D, the density, is taken as the mean of the density at the initial and final pressures.

[ [81] ] Diameters up to 5 inches, inclusive, are actual diameters of standard pipe, see [Table 62] , page [308] .

[ [82] ] Diameters up to 4 inches, inclusive, are actual internal diameters, see [Table 62] , page [308] .