These valves are commonly used for preventing a safe pressure being exceeded in pressurised systems. The lift is proportional to the system overpressure. Particularly suitable for most liquid applications where a ‘small’ discharge often prevents the safe pressure in a system being exceeded. Also suitable for steam, gases & vapour applications where a low discharge is suitable.

Specifications:

Size Range: DN15-DN50 (½” – 2”)
Pressure Range: 0.5 Bar.g (7 PSI) to 20.7 Bar.g (300 PSI)
Pipe Connections:
- Inlet: Threaded ‘G’ BSP Male to BS EN ISO 228/BS 2779
- Outlet: Threaded ‘Rp’ Parallel Female to BS 21/BS EN 10226/ISO 7
- Alternative thread standards, i.e. BSPT or NPT are available upon request.
- Flanged connections also available. Most flange standards can be accommodated.
Features and Benefits:
- Gresswell Valves are quality assurance approved to BS EN ISO 9001: 2015 and manufactured in accordance with BS EN ISO 4126-1 & BS6759.
- Full Cat IV PED approval.
- Only 4 springs are needed to cover the full pressure range.
- Clear operating and maintenance instructions are supplied with each dispatch.
- Screwed/Flanged or a combination of both are available as standard.
Testing:
- All Gresswell Relief Valves are given a hydraulic seat tightness test before leaving the factory and all valves are supplied pre-set.
- Special tests or witness testing can be arranged at extra cost.

Please Note: These valves need to be set to a pressure. Enter your requirements in the comments box at the checkout, otherwise a member of our staff will contact you for the pressure you require and whether a certificate is required. Also available with PTFE and Viton seat.