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 psi | Adjustable psi | Bar | Discharge Connection |
| A140VB2PA | 100 | 50-150 | 3.45-10.3 | 1/4″ NPT (M) |
| A140VB2P1 | 150 | 50-150 | 3.45-10.3 | 1/4″ NPT (M) |
| A140VB2P2 | 145 | 50-150 | 3.45-10.3 | 1/4″ NPT (M) |
| A140VB2PB | 200 | 150-350 | 10.3-24.1 | 1/4″ NPT (M) |
| A140VB2PC | 600 | 350-600 | 24.1-41.4 | 1/4″ NPT (M) |
| A140VB2PD | 300 | 150-350 | 10.3-24.1 | 1/4″ NPT (M) |
| Pressure Relief Valves for High Pressures | |||
| Part No. | Relief Pressure Range, psi |
Bar | Discharge Connection |
| A175VB | 750-1500 | 52-103 | 1/4″ NPT (F) |
| A175VB2 | 1500-2250 | 103-155 | 1/4″ NPT (F) |
| A175VB3 | 2250-3000 | 155-207 | 1/4″ NPT (F) |
| A175VB4 | 3000-4000 | 207-276 | 1/4″ NPT (F) |
| A175VB5 | 4000-5000 | 276-345 | 1/4″ NPT (F) |
| A175VB7 | 350-750 | 24-52 | 1/4″ NPT (F) |
| A175VB7CH (Hast C) | 350-750 | 24-52 | 1/4″ NPT (F) |
| A175VB8 | 50-350 | 3.4-24.1 | 1/4″ NPT (F) |
| A175VB8CH (Hast C) | 50-350 | 3.4-24.1 | 1/4″ NPT (F) |
*Note: When ordering any of the above relief valves, the user may specify a desired set pressure.