Patent ID: 7722085

Claim:
A pipe presenting at least two pipe elements having internal lining and assembled end to end, in which the ends of the two pipe elements are welded to each other, each pipe element comprises: an inner liner of plastic material, presenting at each end a terminal portion of thickness that is reduced relative to the thickness of the main portion of said liner, defining a circularly symmetrical inside surface having an inside diameter that is greater than the inside diameter of the main portion of said liner and terminating at a certain distance from the end of said pipe element; and a single tubular junction sleeve of material that withstands corrosion, having substantially the same inside diameter as said liner, interposed inside the abutting ends of the two pipe elements so as to overlap said terminal portions of reduced thickness of the two liners, said sleeve presenting, at each of its ends, a respective terminal portion of thickness that is reduced relative to the thickness of the central portion of said sleeve, said terminal portions of the sleeve defining an outside surface of outside diameter that is smaller than the outside diameter of the central portion of the sleeve, and a cylindrical inside surface having substantially the same inside diameter as the inside diameter of the cylindrical inside surfaces of the main portions of the liners and of the central portion of the sleeve; wherein: the outside surface of each of said terminal portions of reduced thickness of the inner liner is locked by adhesive bonding of the end of the liner at or near said terminal portion of reduced thickness of the liner against the corresponding inside surface of the steel wall of the pipe, using an adhesive; said outside surface of each terminal portion of said sleeve is a notched surface enabling it to be inserted in and anchored against the inside surface of the terminal portion of reduced thickness of the corresponding liner, thereby providing a mechanical connection between said outside surface of the sleeve and said inside surface of the liner, merely by forcing said sleeve in the axial longitudinal direction XX′ into the inside of said pipe element; and the outside diameter of said cylindrical central portion of the sleeve is less than the inside diameter of the non-lined ends of the steel walls of said pipe element so that said sleeve does not come directly into contact with said steel walls, and cooperates therewith and with the ends of the liners on either side of the sleeve to define an annular chamber.