Relief Valves

A175VB Relief Valve
A175VB Relief Valve

Spring-loaded relief valves should be viewed as supplements and not substitutes for a safety rupture disc as the primary means protecting the vessel and the operator in case of accidental over-pressure. Spring loaded relief valves can be added to a reactor or vessel to:


  • Relieve pressures near the maximum operating pressure.
  • Reseal once excess pressure has been relieved.
  • Protect low pressure components at pressures below available rupture disc ranges.

The relief valves listed below can be installed on any Parr vessel. These relief valves are stainless steel and have FKM O-rings. Other valve and O-ring materials are available on special order.

Relief Valves
Part No. Relief Pressure Range psi Discharge Connection
A140VB2PA 50-150 1/4″ NPT (M)
A140VB2P1  50-150 1/4″ NPT (M)
A140VB2PB 150-350 1/4″ NPT (M)
A140VB2PC 350-600 1/4″ NPT (M)
A140VB2PD 150-350 1/4″ NPT (M)
A175VB 750-1500 1/4″ NPT (F)
A175VB2 1500-2250 1/4″ NPT (F)
A175VB3 2250-3000 1/4″ NPT (F)
A175VB4 3000-4000 1/4″ NPT (F)
A175VB5 4000-5000 1/4″ NPT (F)
A175VB7 350-750 1/4″ NPT (F)
A175VB8 50-350 1/4″ NPT (F)