CV KV value is an important parameter and technical index of the control valve.
CV (Circulation Volume) value is the abbreviation of flow coefficient, which represents the flow capacity of the valve. That is, the volumetric flow rate of the pipeline medium through the valve per unit time when the pipeline maintains a constant pressure. The CV value is defined as a temperature of 60 (60 F = 15.) with the valve fully open and the differential pressure across the valve at 1 pound5) The flow rate of water through the valve within one minute, measured in gallons.
In China, the kv value is usually used to represent the flow coefficient, which is also the volume flow rate (or mass flow) of the pipeline medium through the valve when the pipeline maintains a constant pressure per unit time, and the kv value is defined as: under the condition that the valve is fully open and the pressure difference between the two ends of the valve is 1bar, the flow rate of water with a temperature of 20 flows through the valve within one hour, measured in m hours.
Because the unit of pressure and the unit of volume are not the same, there is a relationship between the two: CV=1167kV (must flow unit: m h, pressure unit: bar).
1) The flow coefficients CV and KV are not fully expressed as the flow rate of the valve. Taking KV as an example, the only way to do this is when the medium is water at room temperature and the pressure difference is 100KPA. Under the same kv value, the flow rate through the valve is different due to the difference of r and p. For example, a control valve with KV=50 means that when the pressure difference between the two ends of the valve is 100kPa, the water volume per hour is 50m.
2) kv is the flow coefficient, so there is no unit. However, many materials and manuals have been mistakenly brought to the unit, which is worth correcting.