What is a Pressure Relief Valve

All drilling fluid circulation pumps are positive displacement type pumps and so they deliver a constant volume of fluid irrespective of the pressure against which the pump is pumping.

In a drilling operation, this means that if a blockage occurs at the drill bit or in the borehole, the pressure in the system will increase until something happens to relieve the pressure; for example, a waterswivel hose may burst or one or more cylinder covers may be blown off the circulation pump. The pressure relief valve is therefore a critical piece of safety equipment on the drill rig.

Pressure relief valves from different manufacturers may look different, but all pressure relief valves fitted to positive displacement pumps used in drilling applications are spring type relief valves and they work on the same principle.