Sealing and restraint system for joining plastic pipe sections having pre-formed sockets
A seating and restraint system is shown for joining the spigot and socket ends of two sections of plastic pipe to form a pipe joint. The socket pipe ends are preformed at the factory with an internal raceway which receives both a sealing ring and a companion gripping ring. The sealing ring is an elastomeric member having a periphery with a protruding ear formed at one circumferential location. The companion gripping ring is a hardened member having one opening gap in the circumference thereof. The protruding ear on the sealing ring fits within the opening gap in the gripping ring, engagement of the protruding ear within the opening gap serving to prevent extrusion of the sealing ring within the gap in the gripping ring and also limiting closure of the gripping ring after engagement of the spigot end with the socket pipe end as the pipe joint is assembled.
1. A method of joining a first longitudinal section of plastic pipe to a second longitudinal section of plastic pipe to form a secure pipe joint, each of the sections of plastic pipe each having a spigot for mating with a socket end of a next adjacent pipe section, the socket ends each being preformed with an internal raceway formed adjacent a mouth opening thereof which is formed during the manufacture of the pipe section, the method comprising the steps of:
first, installing a sealing element within the raceway of the socket end of one section of plastic pipe, the sealing element comprising an elastomeric sealing ring having a periphery and having a protruding ear located at one circumferential location about the periphery thereof, the sealing element being installed by temporarily collapsing the sealing element inwardly upon itself and positioning the sealing element in the raceway, and thereafter allowing the sealing element to return to a normal uncollapsed state;
next, installing a restraining element within the raceway of the socket end of the same section of pipe, the restraining element comprising a hardened gripping ring having an external peripheral surface and an internal peripheral gripping surface, the griping ring having an opening gap at one circumferential location about the periphery thereof;
wherein the protruding ear of the sealing ring engages and fits within the opening gap in the gripping ring when the gripping ring is installed within the raceway of the socket end of the section of plastic pipe, whereby engagement of the protruding ear within the opening gap serves to prevent extrusion of the sealing ring within the gap in the gripping ring and also limits closure of the gripping ring after engagement of the spigot end with the socket pipe end as the pipe joint is assembled.
2. The method of claim 1 , wherein the two sections of plastic pipe are molecularly oriented plastic pipe.
3. The method of claim 1 , wherein the gripping ring has an external diameter and an internal diameter, and wherein the opening gap in the gripping ring can be forced closed to thereby temporarily decrease the external diameter of the gripping ring, so that the gripping ring can be positioned within the raceway in the socket end of the plastic pipe.
4. The method of claim 1 , wherein the sealing ring and the gripping ring are provided with interlocking profiles which help to ensure retention of the sealing ring by the gripping ring after the sealing ring and gripping ring have been installed in the raceway within the socket end of the plastic pipe.
5. The method of claim 1 , wherein the internal peripheral gripping surface of the gripping ring comprises a series of gripping teeth which allow movement of a mating spigot pipe end within the mouth opening of the spigot pipe end in a first longitudinal direction as the pipe joint is being assembled, but which restrain movement in a second, opposite longitudinal direction.