This sizing calculator determines the flow coefficient (Cv/Kv) required to deliver a known flow rate at a known inlet pressure, outlet pressure and inlet temperature.
This calculator can be used for both gases and liquids.
If the PRV must operate across a range of pressures/flows/temperatures, size the PRV according to the maximum flow coefficient which can be calulated using:
- Maximum flow rate requirement
- Minimum inlet pressure
- Maximum inlet temperature
- Maximum outlet pressure
- The sizing guide will display if the flow is choked/unchoked (gases) or cavitating/non-cavitating (liquids).
The calculator outputs the minimum inlet/outlet pipe diameter required to satisfy a maximum allowable pipe velocity (30 m/s default).
The minimum outlet diameter calculation assumes that the outlet temperature is equal to the inlet temperature.
The Oxford Flow PRVs are shown under 'Regulator Sizes.'
The percentage open of each Oxford Flow PRV at the user-specified flow condition is displayed in the Regulator Sizes table. A value of 100% means the PRV is fully open,
0% that the PRV is fully closed, and greater than 100% that the PRV cannot deliver the required flow condition.
Ideally, select a PRV that is 75-95% open at the maximum flow coefficient condition (see above for details on the correct inmaximum flow coefficient).
The sizing calculator uses BS EN 60534-2-1 (2011) and a minimum choked pressure ratio (no pressure recovery) from the compressible isentropic flow equations for gases (www.grc.nasa.gov). Copyright © Oxford Flow 2018