Pipe flow calculators
Calculator Description
Control valves sizing calculator can be used to calculate maximum flow rate through control valve for given pressure drop and known flow coefficient of control valve C_{v}.

Calculate:
 Maximum flow rate through control valve
 Flow velocity
 Flow coefficient

Input:
 Valve diameter
 Pressure drop
 Liquid density
Calculator Features
 For turbulent flow of water or other incompressible fluid
 Metric and imperial flow coefficient calculation
Control valve sizing is based on the flow coefficient C_{v} calculation. Calculation of C_{v} is made for required flow rate and related pressure drop in control valve. With flow coefficient C_{v} calculated, size of control valve can be selected. Two control valves from different manufacturers can be compared in terms of flow capacity for certain pressure drop and the same control valve size comparing its C_{v}.
C_{v} calculation is based on the relation between pressure drop and flow rate in control valve which is for complete turbulent flow following power law where flow coefficient C_{v} is the proportional constant. C_{v} is determined experimentally by control valve manufacturers.
Control valve C_{v} is expressed as the flow rate of water in gpm u.s. (m^{3}/h) for a pressure drop of 1 psi (1 bar) across a flow passage (flow coefficient: C_{v}imperial, K_{v}metric).
Control valve calculator can be used for turbulent flow of water or other incompressible fluid. For compressible flow of gases and steam gas flow coefficient C_{g} should be calculated.
Flashing and cavitation and chocked flow may reduce the control valve capacity and it is not in this version of control valve calculator.
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Q: Calculate flow coefficient of control valve for 500 gpm and pressure difference of 30 psi. Fluid density is 62 lb/ft^{3}. Valve diameter is 2 in
A: Calculation setup:
Input values:
q = 500 gpm US
D = 2 in
deltap = 30 psi
rho = 62 lb/ft^{3}
Q: Calculate pressure drop in control valve with flow rate of 500 gpm and flow coeffient of C_{v}150. Fluid density is 62 lb/ft^{3}. Valve diameter is 1.5 in
A: Calculation setup:
Input values:
q = 500 gpm US
D = 1.5 in
C_{v} = 150
rho = 62 lb/ft^{3}
Q: Calculate flow rate through control valve with flow coeffient of C_{v}150 and pressure drop of 4 psi. Fluid density is 62 lb/ft^{3}. Flow velocity is 5 m/s
A: Calculation setup:
Input values:
v = 5 m/s
C_{v} = 150
deltap = 4 psi
rho = 62 lb/ft^{3}
Control valve flow coefficient calculation is based on the following formula:
Read more about used theory on flow in valves and fittings page.
If you experience problems with calculator start try to find answers on instructions page.
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