Control Valve Cv Si Units. The valve flow coefficient cv or its metric equivalent kv has been adopted universally as a comparative value for measuring the capacity of control valves. The flow of water through a valve at 60°f in us gallons/minute (gpm) at a pressure drop of 1lb/in².
Valve sizing calculations (traditional method) 626 technical introduction fisher® regulators and valves have traditionally been sized using equations derived by the company. Just to make things a bit interesting and more confusing the resistance of a valve can also be expressed in terms of k, the resistance coefficient. It allows you to calculate the flow or c v (flow coefficient) to make the relationship visible between the pressure drop (the difference in pressure between two points in a network transporting a liquid or gas) and the flow rate.
Flow coefficient is an imperial measurement and is defined as:
C v & flow calculator. M 3 /s, pascal and kg/m 3. Engineering units are by default set to us units, but can be easily changed to si units. Flow for a given cv is typically calculated from the following formula.