Heat-fusible gasket and method of manufacture

摘要

A heat-fusible gasket for affecting a flexible seal between two adjoining components of a coupling, such as the spigot end of a section of plastic pipe and a bell coupler to be fitted thereover. The gasket has an inner core which is constructed of an elastomeric material, and outer opposing sealing surfaces that are formed at least in part of a heat-fusible material that is compatible with the heat-fusible components with which the gasket is intended to engage. The gasket is co-extruded in continuous lengths with electrically conductive heat resistance wires embedded in the outer compatibly heat-fusible layers. For annular gaskets, the co-extruded lengths of gasket material may be cut and spliced into any desired diameter gasket. Upon connection to a power source, the gasket seal is perfected through electrofusion along the opposing sealing surfaces of the gasket, thereby providing enhanced sealing capability.

主权项

1. A gasket for forming a flexible watertight seal between two adjoining components of a coupling, the gasket comprising:
(a) an annular sealing member defining a central opening and having a longitudinal axis extending circumferentially around said central opening, said sealing member having a core formed at least in part of a generally flexible elastomeric material; (b) a first portion of said sealing member being in direct engagement with a sealing surface of one of the adjoining components of the coupling; (c) a second portion of said sealing member being in direct engagement with a sealing surface of the other adjoining component of the coupling; (d) at least one of said first portion and said second portion of said sealing member comprising a homogeneous covering of material which extends continuously along said longitudinal axis substantially the circumference of said sealing member, and which is compatibly heat-fusible with at least one of the adjoining components of the coupling; (e) said compatibly heat-fusible material being of a different material composition than said core; and (f) said covering of material being devoid of interstices and maintaining watertight continuity throughout its length at all times when stretched circumferentially in the direction of said longitudinal axis.