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Cv = Flow coefficient (number of U.S. gallons of water flowing through a valve with a pressure drop of 1 psig)
G = Specific gravity of flowing media at system temperature. water = 1 @ 60 deg. F.)
DELTA P = Pressure drop, P1 -P2, psig
Cf = Critical flow factor (0.65 @ 60 deg.; 0.55 @ 90 deg.)
P1 = Inlet pressure, psia
P2 Outlet pressure, psia
Q = Flow, gallons per minute, GPM
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T = Absolute temperature of flowing media, deg. R (deg. F + 460)
q = Flow, standard cubic feet per hour, SCFH
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W = Flow, lbs./hr.
Add 7% to Cv for each 100° F of super heat.
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K = Constant for vapor
Vapor |
K |
Freon 11 |
7.4 |
Freon 12 |
7.1 |
Freon 14 |
8.4 |
Freon 114 |
8.3 |
Ammonia |
2.7 |
Dowtherm A |
5.6 |