Calculate pilot operated relief valves in liquid systems.
The minimum discharge area of a pilot operated relief safety valve in a liquid system can be calculated as
A = q SG1/2 / (36.81 Kvisc dp1/2) (1)
A = discharge area (Square Inches)
q = relieving capacity (Gallons per Minute)
SG = Specific Gravity of the fluid
Kvisc = correction factor due to velocity - 1.0 for most water systems
dp = differential pressure - set pressure (psig) + over pressure (psig) - back pressure (psig)