The flow coefficient Cv for a water control valve can be estimated with the diagram below:
Example - Required Cv for a water control valve
With water flow 6 gpm and designed pressure drop 10 psi through a control valve - the required flow coefficient Cv can be estimated to ~2 as indicated in the chart below.
Control Valve terminology, bodies, trim, flow characteristics, Cv and Kv sizing, noise, actuators and positioners
Flow coefficients - Cv - for typical ball valves - reduced and full bore.
Typical flow coefficients - Cv - for butterfly valves.
How to add flow coefficients for control valves in series or parallel.
Comparing flow coefficients Cv to flow factors Kv.
Calculate flow coefficients for the design of control valves - Imperial units.
Critical pressure ratios for water and other liquids.
Designing steam control valves and their Kv values.
Flow coefficients - Cv - and flow factors - Kv - for straight through diaphragm valves.
The valve authority expresses the ratio between pressure drop across the control valve compared to total pressure drop across the whole system.
Sizing of water control valves - SI units
Designing water process control valves and their Kv values.