Answer / abhishekk

pressure safety valve is automatic relieves the static
pressure on a gas..usually it opens completelly ..while
relief valve relieve the static pressure in a liquid filled
,its opens proportionally with increasing pressure...
PSV is used in case of gas and PRV is used in liquid.

Answer / manish dhamani

Relief valve (RV) - A pressure relief valve is a safety
device that relieves overpressure in a vessel or piping.
an automatic system that relieves liquid pressure above a
pre-set limit and opens propotionally to yhe liquid
pressure.
Safety valve (SV) - an automatic system that relieves gas
pressure above a pre-set limit (e.g., safety valves on
pressure cookers) usually it opens completelly
The difference being that PSVs have a manual lever to
activate the valve in case of emergency.

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