METHOD OF MAKING A PLASTIC PIPE UNION PIECE EMBEDDED INTO PIPE END BY ELECTRIC FUSION AND PLASTIC PIPE UNION PIECE USED IN THAT METHOD

摘要

A method for the manufacture of an electrofusion fitting comprises the following steps: (i) assembling an electrical heating element 7 and a layer in the form of a mesh tube 13 of thermoplastic polymeric sheet material on a support member which is a collapsible winder mandrel 1; (ii) heating the layer of thermoplastic polymeric sheet material in order to soften the material and cause it to flow in order to form a shape-retaining structure 14 with the electrical heating element 7; and (iii) moulding a body of thermoplastic polymeric material over the structure produced in (ii) and mounted on a collapsible mandrel to form an electrofusion fitting 26. The structure 14 is removed from the mandrel 1 before the final step of moulding over the structure 14.