Flow coefficient (Cv for control valve) is the capability of a valve to flow a liquid. One Cv is equal to a flow of 1 gallon per minute (gpm) of water at 60 degrees Fahrenheit with a pressure differential of 1 pound per square inch. The larger the Cv, the greater the flow in gpm. If you are dealing with a pressure differential other than 1 pound per square inch (psi), then gpm can be calculated in a few steps.
Instructions
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1
Determine the pressure differential of the valve by subtracting the downstream pressure from the upstream pressure.
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2
Take the square root of the pressure differential.
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3
Multiply the square root of the pressure differential by the valve coefficient to calculate the flow in gallons per minute.