Apparatus and method for coating pipes

Abstract

A system for first heating a section of pipe and then wrapping a sheet of heat-shrinkable material around the pipe to cover the section, the heat-shrinkable material having an outer polyethylene side and an inner mastic side which goes against the pipe, the mastic side forming a mechanical bond to the pipe when heated and having a lower melt temperature than the shrink temperature of the material, comprising arranging a plurality of induction coil assemblies in spaced relation around the pipe section, the induction coil assemblies having relatively arcuate induction coils therein, mounting the coils on a rotation fixture to form an arcuate surface adjacent to and parallel with the surface of the pipe, locating a heater assembly on the rotatable fixture between a pair of induction coil assemblies, rotating the rotatable fixture around the pipe section to heat the pipe section to the melt temperature of the mastic, wrapping a sheet of heat-shrinkable material around the pipe to form a sleeve with overlapping ends, placing a closure patch having a lower mastic surface over the overlapping ends of the sleeve, activating the heater assembly to bond the closure patch to the overlapping ends of the sleeve, and thereafter rotating the rotatable fixture while simultaneously applying a alternating electric potential to the induction coil assemblies to heat the pipe to a relatively higher shrink temperature thereby shrinking the applied sleeve.

Dependencies are inferred from the claim text.