US Patent 10082137 Over pressure relief system for fluid ends

A relief valve assembly includes a housing assembly defining a chamber therein. The relief valve assembly includes a piston. The piston may be at least partially disposed within the chamber. The relief valve assembly includes a pilot inlet. The pilot inlet may be configured to provide a pilot pressure proximate a second end of the chamber. The relief valve assembly includes an overpressure inlet sealed from a first end of the chamber by the piston. The overpressure inlet may be configured to provide an inlet pressure which may actuate the piston when the inlet pressure exceeds the pilot pressure.