Valve assembly and piston with double o-ring interface and relief passage

Abstract

A valve assembly includes a housing having an interior wall defining a chamber having a longitudinal axis. A piston is disposed in the chamber and is movable between first and second positions along the longitudinal axis, wherein the piston includes a piston head. The piston head has opposite first and second sides, longitudinally spaced first and second peripheral grooves disposed between the first and second sides, wherein the first and second grooves define a space therebetween, and a relief passage extending radially inwardly from the first groove and communicating between the space and the first side of the piston. Longitudinally spaced first and second O-rings are disposed in the first and second grooves and engage the interior wall.

Dependencies are inferred from the claim text.