Abstract: Two outer steel pipes (16 and 16A) are each lined by corrosion resistant lining pipes (18 and 18A) of compressible plastics material which stop short of the ends (20, 20A) of the outer pipes to leave an annular recess or counterbore (24 and 24A) at each of those ends. A tubular bridging-member (2) of ductile, plastically deformable, corrosion resistant material, for example brass or stainless steel has two tubular end portions (4 and 6) extending in opposite directions from an intermediate tubular portion (8) having an outer diameter greater than that of the end portions (4 and 6) and an inner diameter greater than that of the said end portions. The end portions (4 and 6) are encircled by ribs (12). Initially the outer diameter of the end portions (4, 6) is less than that of the inner diameter of the lining pipes (18, 18A). Thus each lined pipe (16, 16A) can be fitted over the respective end portions (4 and 6) with the intermediate portion (8) occupying the combined counterbore (24, 24A).

Abstract: A method and apparatus for lining a pipe with a polymer liner in which the liner is pulled through a die to reduce the liner's diameter and through the pipe and on removal of the pulling load, allowing the liner to revert to at least the minimum internal diameter of the pipe, wherein the liner has a maximum diameter before entering the die and a minimum diameter in the die. The die having an aperture which is symmetrical with respect to a central, longitudinal axis and comprising in the direction that the liner is passed an entry, a throat and an exit. The diameter of the aperture decreasing over the entry to a minimum to the throat and increasing over the exit. The entry of the die, when viewed in a sectional plane extending longitudinally of the liner and containing the axis, is convex over substantially an entire axial length between where the liner first contacts the die and the throat, wherein the liner substantially continuously engages the die over substantially the entire axial length.

Abstract: The invention provides a joint 80 for two steel pipes 50, 52 each containing a liner 54, 56 of polyethylene. The invention also provides an electrofusion fitting for joining the liners 54, 56; a method of making the fitting and a method of making the joint 80. The joint 80 consists of an electrofusion fitting having two frusto-conical outer end surfaces which match similar surfaces on the insides of the end portions of the liners 54, 56. Fusion welded joints are formed at the interfaces between the frusto-conical surfaces. A body of insulating material 66 is received in a central recess in the fitting and protects the fitting from the high temperature of the seam 70 between the steel pipes 50, 52. The frusto-conical surfaces make an angle of 10.degree. or less with the longitudinal axis of the fitting. A support body 14 of metal or of synthetic plastics material contained by the electrofusion fitting ensures that the fitting is adequately supported during electrofusion.

Abstract: A method of lining a pipeline 24 intended to carry gas, oil, water, sewage or chemicals in which a cross-linked polymeric liner pipe 10, which has been reduced from its original diameter to a lesser diameter or to a shape of reduced maximum dimension, is pulled through the pipeline 24. The lesser diameter is less than the least inner diameter of the pipeline 24. After the liner pipe 10 has been fully pulled through, the pipe liner 10 is heated by means of a source 60 of visible or infrared radiation forming part of a pig assembly 50 to cause it to revert to the pipeline. The pig assembly or assemblies are stationary at zones 70 where service connections are to be made. Subsequently, the remaining liner pipe 10 is reverted by pulling the source 60 through the liner pipe 10.

Abstract: A die for reducing polyethylene pipe temporarily to enable it to be inserted in a pre-existing metal pipe is made of cast iron and has formations by which the die is splittable into two portions. The formations receive cylindrical bars which are squeezed together by a hydraulic squeeze off machine. Each formation is a U-shaped aperture with a saw cut extending from the base of the U into the ligament beneath the formation. The saw cut acts as a stress raiser. In a modification only one formation is provided. The die is made of grey cast iron or some other brittle material.