Patent ID: 6278096
Filing Date: 2001-08-21
Classification: B29C,B29D,F16L

Abstract:
A method for providing electrical insulation over a field joint in a single heated insulated pipeline for subsea application, comprising:(a) providing joints of pipe, the joints having ends and a prefabricated layer of thermoplastic insulation;(b) welding two joints of the pipe to form a weld area between the joints;(c) placing a mold made from a material having low magnetic permeability around the weld area to form a mold cavity;(d) injecting a thermoplastic into the mold cavity;(e) placing an induction heating coil around the field joint; and(f) providing a selected amount of electric current to the induction heating coil for a selected time to heat the pipe in the vicinity of the weld area such that the thermoplastic becomes flowable for an effective distance from the pipe.