Pressure Relief Valves

A175VB Relief Valve
A175VB Relief Valve
A140VB2 Relief Valve
A140VB2 Relief Valve

Spring-loaded relief valves should be viewed as supplements and not substitutes for a safety rupture disc. The rupture disc is the primary means for protection of the operator and the vessel 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 constructed of stainless steel and have FKM O-rings. Other valve and O-ring materials are available on special order. Relief valves with CE Certification are also available.

Pressure Relief Valves for Low Pressures
Part No.Preset psiAdjustable psiBarDischarge
A140VB2PA10050-1503.45-10.31/4″ NPT (M)
A140VB2P115050-1503.45-10.31/4″ NPT (M)
A140VB2P214550-1503.45-10.31/4″ NPT (M)
A140VB2PB200150-35010.3-24.11/4″ NPT (M)
A140VB2PC600350-60024.1-41.41/4″ NPT (M)
A140VB2PD300150-35010.3-24.11/4″ NPT (M)


Pressure Relief Valves for High Pressures
Part No.Relief Pressure
Range, psi
A175VB750-150052-1031/4″ NPT (F)
A175VB21500-2250103-1551/4″ NPT (F)
A175VB32250-3000155-2071/4″ NPT (F)
A175VB43000-4000207-2761/4″ NPT (F)
A175VB54000-5000276-3451/4″ NPT (F)
A175VB7350-75024-521/4″ NPT (F)
A175VB7CH (Hast C)350-75024-521/4″ NPT (F)
A175VB850-3503.4-24.11/4″ NPT (F)
A175VB8CH (Hast C)50-3503.4-24.11/4″ NPT (F)

 *Note: When ordering any of the above relief valves, the user may specify a desired set pressure.

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