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# Pilot Operated Safety Valves in Liquid Systems

## 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)

where

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)

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## Citation

• The Engineering ToolBox (2005). Pilot Operated Safety Valves in Liquid Systems. [online] Available at: https://www.engineeringtoolbox.com/safety-valves-liquids-pilot-d_875.html [Accessed Day Month Year].

Modify the access date according your visit.

5.16.12

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