Dual seal pipe coupling

Abstract

An improved dual seal pipe coupling is provided of the type having matingly interfitting male and female pipe fittings formed on adjacent ends of a pair of conduit members, wherein at least one of a pair of seal rings is vented at low pressure to prevent pressure build-up and potential seal ring distortion or damage upon initial assembly of the pipe fittings. The seal rings are seated respectively within a pair of axially spaced-apart recessed grooves formed on one of the pipe fittings for slidably and sealingly engaging the other one of the pipe fittings upon assembly therewith. A bypass vent is formed in at least one of the seal ring grooves, to include a shallow recessed channel underlying the associated seal ring and leading axially to a smoothly curved and generally arch-shaped relief port formed in an outboard side wall of the seal ring groove. Upon initial assembly of the pipe fittings, when an incompressible fluid such as water is trapped at relatively low pressure between the pair of seal rings, the fluid can escape through the bypass vent to prevent seal ring distortion or damage. However, in the presence of higher fluid pressure, the seal ring resiliently conforms with and seals against the smoothly curved recessed relief port to prevent fluid escape.