METHOD OF FORMING A WELDED JOINT BETWEEN POLYOLEFINIC MEMBERS

摘要

A polyethylene pipe (10) is jointed by a welded joint to a cross-linked polyethylene coupler (14) which has been expanded to make the coupler heat recoverable. Radiant energy (eg light in the visible spectrum or infra-red light) illuminates the outer surface of the coupler (14) supplied by an array of150W reflector lamps (20). The coupler (14) shrinks and is forced into engagement with the pipe (10) and the pipe (12) to join the pipes. A fusion welded joint is formed between the coupler (14) and each pipe (10), (12). In an alternative a pipe is drawn down and inserted in an aperture through the wall of another pipe. A lamp is inserted in the drawn down pipe and the radiant energy causes the pipe to expand into engagement with the edge of the aperture and to be joined to it by a welded joint.