Question

How do you calculate Cv flow?

Answer 1

Answer:

A practical example, if we wanted to calculate Cv to select a valve for 10 GPM flow with a required ΔP of 4, first find the square root of the ΔP √ 4=2, and use that to divide the flow of 10 GPM 10/2 = 5, which results in a Cv requirement of 5.

Answer 2

Answer:

Cv by definition is the number of gallons per minute (GPM) a valve will flow with a 1 psi pressure drop across the valve. For example a valve with a Cv of 10 will flow 10 GPM with a 1 psi pressure drop. The formula used to select the valve Cv with the specified differential pressure is: Cv=GPM/((SQ RT(∆P)).

Control Valve Sizing:

• When sizing a control valve, the most common approach is to calculate the flow coefficient, Cv which is a measure of the capacity of the valve body and trim

• C = Q/N1 * √ (ρ1/ρ0) / (∆P)

• ρ1/ρ0 is the relative density

• Fluid Density: 965.4 kg/m3

• Flow Rate (Q): 360 m3/h