Coupling for lined pipe

The method of joining the open ends of two sections of metal pipe each having a plastic liner bonded to the internal surface thereof to form a continuously lined conduit comprising the steps of:

• (a) inserting a plastic collar in the open end of one of said pipe sections, said plastic collar comprising a cylindrical body having outer dimensions substantially conforming to the inner dimensions of the liner in the pipe and having a flange extending radially from one end thereof to mate with the end facing of the open end of the pipe;
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• (b) forming an interference fit coupling between said pipe sections by telescopically inserting the open end of said one pipe section into the open end of the other pipe section until said flange mates with the liner in said other pipe section.

The method of joining the open ends of two sections of metal pipe each having plastic liners bonded to the internal surfaces thereof to form a continuously lined conduit comprising the steps of:

• (a) inserting a plastic collar in the open end of each of said pipe sections, said plastic collar comprising a cylindrical body having outer dimensions substantially conforming to the inner dimensions of the liner in the pipe and having a flange extending radially from one end thereof to mate with the end facing of the open end of the pipe;
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• (b) inserting the open ends of said pipe sections in opposite ends of a coupling sleeve having an internal diameter less than the external diameter of said pipe sections prior to insertion of said pipe ends thereinto until said flanges meet in abutting relationship forming an interference fit between said pipe sections and said coupling sleeve.

An interference fit coupling joint interconnecting two sections of plastic lined metal pipe comprising:

• (a) a plastic end face collar positioned within the end of each pipe section, said end face collar comprising a cylindrical body with its outer surface mating with the inner surface of the liner in the end portion of the plastic liner and having a flange radially extending from one end thereof, said flange mating with the end face of said pipe section;
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• (b) a coupling sleeve comprising a cylindrical body having an internal diameter less than the external diameter of said pipe sections prior to assembly of said coupling joint surrounding the open ends of said pipe sections and maintaining the end faces of said end face collars in abutting relationship.