Patent ID: 8444186

Claim:
A combination seal and restraint system capable of both joining and sealing a female plastic pipe to a mating male plastic pipe having an interior surface and an exterior surface, the seal and restraint system comprising: a sealing ring formed as an elastomeric body, the sealing ring being integrally installed within a groove formed in a belled end of the female pipe during the manufacture of the belled pipe end; a companion restraint mechanism for the elastomeric sealing ring which allows movement of the mating male pipe relative to the belled end of the female pipe in a first longitudinal direction but which restrains movement in a second, opposite relative direction, the restraint mechanism including a ring shaped housing which is also integrally installed within the belled pipe end during manufacture and which has a circumferential interior region; the restraint mechanism also including a companion gripping ring which is installed as an insert within the circumferential interior region of the housing, the gripping ring having an exterior surface and having an interior gripping surface with at least one row of gripping teeth; and wherein a selected one of the interior circumferential region of the housing and the exterior of the gripping ring have applied thereto a low friction coating; wherein the coating which is applied to a selected one of the exterior surface of the gripping ring and the interior surface of the housing is a permanent, sprayed-on fluoropolymer coating which is applied and then heat treated; wherein a base, corrosion resistant coating is first applied to the selected one of the exterior surface of the gripping ring and the interior surface of the housing, followed by the fluoropolymer coating; wherein the base coating is selected from the group consisting of an electrostatically applied corrosion resistant powder coating, an aqueous electrophoretically applied coating, an aqueous autophoretically applied coating and a solvent or aqueous corrosion control coating; wherein the gripping ring exterior surface has a sloping profile which contacts a mating sloping interior surface of the housing, whereby insertion of a male pipe end within the female, belled pipe end causes the gripping ring exterior surface to ride up the sloping interior surface of the housing as the row of teeth on the gripping ring interior surface engage the male pipe end, the low friction coating serving to facilitate the movement of the gripping ring along the sloping profile of the housing in a direction generally along the same first longitudinal direction as the mating male pipe end.