Buckling pin relief on a pump bypass that kept simmering
Replacing spring relief valves on a positive displacement pump bypass, where a valve that opens gradually is a valve that passes product it should not.
- Scope
- Pump bypass and vessel relief
- Supplied from
- Safety Device
A spring safety valve simmers before it lifts. On most duties that is harmless. On a positive displacement pump against a closed discharge it is not: pressure builds fast, and a valve that leaks past its seat on the way up is passing product for the whole of the ramp.
A buckling pin device does not simmer. It holds to the pin's rating and then opens fully, which is why BPCV™ is listed for pump bypass duty specifically. The trade is that a pin is a consumable: once it goes, it is replaced rather than reset.
What went in
- BPCV™ on the bypass lines, sized to the pump's discharge.
- BPRV™ on the vessels feeding them.
- ARI-SAFE flanged angle pattern safety valves where the duty was conventional and a spring valve was the right answer.
The last line is the point worth making. Buckling pin is not a replacement for spring relief across the board; it earns its place on the duties that punish a spring. Both sit on the Safety Device page.
Sizing relief for a bypass duty
Give us the set pressure, the line size and whether the service is liquid or gas. Back pressure conditions and the area classification decide the rest.
