8/20/2019 PRV and PSV

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Pressure Relief Device

• Pressure Relief Valve – Term used to describe relief device on liquid filled vessel. For such of 

valve, opening is proportionally increased in vessel pressure. Hence opening valve is notsudden, but gradually if the pressure gradually increase. 

• Pressure Safety Valve – Term used to describe relief device on compressible fluid or gasfilled vessel. For such a valve the opening is sudden. When the set pressure of the valve isreached, the valves open almost full.

Rupture Disk vs PSV