Fluid-tight coupling system for corrugated pipe

Abstract

A bell and spigot coupling system is provided for joining corrugated plastic pipe which improves the coupling's sealing capability with increasing hydrostatic pressure, and causes a substantial component of the force generated therefrom to be absorbed axially through the coupled sections of adjoining pipe. The spigot end of one pipe which is received within a bell coupler for an adjoining pipe terminates in a small annular bed-forming rib which forms a gasket bed that holds a gasket compressed against a radially extending gasket sealing surface of the bell coupler. Inward protruding latches formed in the bell coupler engage the adjoining section of corrugated pipe to resist axial separation and hold the gasket compressed against the sealing surface of the bell coupler. The sealing surface of the bell coupler contours the spigot end of the adjoining pipe and forms radially constricting pathways at opposite sides of the gasket. The presence of either internal or external hydrostatic pressure on the coupling joint causes the gasket to wedge into one of the opposing radially constricted pathways, thus transferring the force generated by such pressure axially through the coupled sections of pipe.