What does the CV value of a valve mean?

Flow coefficient Cv flow coefficient Cv Flow coefficient in imperial units. Numerically equal to the number of US gallons of water at a temperature of 40℉-100℉ flowing through the valve in 1 minute at a pressure drop of 1psi (6894.8Pa)

CV represents the flow capacity of the valve. The Cv value is defined as follows:: Cv=V [G/ (P 1 -P 2)] 1/2 V---Maximum flow rate (US gallons/min) P 1 --- Inflow side pressure (lb/in 2) P 2 --- Outlet side pressure (lb/in 2) G--- Specific gravity of the circulating medium in the valve (water = 1) Domestic * Usually called Kv, Kv represents the flow capacity of the valve. Its definition is: When the regulating valve is fully open, the pressure difference ΔP across the valve is 100KPa, and the fluid weight r is 1gf/cm3 (i.e. normal temperature water), the flow rate flowing through the regulating valve per hour is measured in m3/h or t/h. Cv=1.167Kv

Definition of flow coefficient For incompressible fluids, Kv is a function of Q and △P. The Kv value is different when △P and r are different. In order to reflect the flow coefficient of different regulating valve structures and different diameters, it is necessary to unify the same test conditions with the regulating valve. Under the same test conditions, the size of Kv reflects the flow coefficient of the regulating valve. Therefore, the flow coefficient Kv of the regulating valve is defined as: When the regulating valve is fully open, the pressure difference ΔP across the valve is 100KPa, and the fluid weight r is lgf/cm3 (i.e. normal temperature water), the flow rate flowing through the regulating valve per hour (because at this time) is measured in m3/h or t/h. For example: There is a regulating valve with Kv = 50, which means that when the pressure difference across the valve is 100KPa, the water volume per hour is 50m3/h. 2. Conversion of Kv and Cv values ​​In foreign countries, the flow coefficient is often expressed as Cv, and its definition conditions are different from those in China. Cv is defined as: When the regulating valve is fully open, the pressure difference ΔP across the valve is 1 pound/inch2, and the medium is 60°F clean water, the flow rate flowing through the regulating valve per minute, measured in gallons/minute. Since the definitions of Kv and Cv are different, the values ​​measured in the test are different, and the conversion relationship between them is ； Cv = 1.167Kv (5)

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