Tubing and fittings with cast-in-place liners

Claim 1

In combination: a first tubular conduit comprising a central tubular liner and an outer organic plastic jacket cast upon and surrounding said liner and having an outer wall, said conduit having an end, said outer jacket being recessed from said end to expose the surface of a length of the central liner, and to form an abutment shoulder on the end of said outer jacket; a sleeve member having a central passage adapted to fit over and embrace said outer wall of said outer jacket, an internal step so disposed and arranged as to bear against said abutment shoulder, and a tapered forming surface which enlarges as its extends away from said abutment shoulder, said exposed portion being displaced against the forming surface whereby to form a tapered seal surface; a second tubular conduit having a central tubular liner, an outer organic plastic jacket cast upon and surrounding said last-named tubular liner, said jacket having adjacent said end an abutment surface, a flange on said last-named liner engaging said last-named abutment surface, and a tapered nose on said liner extending beyond said last-named end forming a tapered seal surface that is complementary to said seal surface on said first tubular conduit, whereby said tubular conduits are joined and sealed at the said ends by abutment of said seal surfaces; and compression means engaging said tubular conduits and holding them together.