Method for lining lateral and main pipes

Abstract

A generally U-shaped lateral liner having a radially outwardly directed flange at its proximal end is drawn through a main pipe into a lateral pipe to be lined. A generally U-shaped main pipe liner is drawn through the main pipe to be lined, with a side wall portion overlying the radial flange of the lateral liner. Steam is supplied to reform the main liner into a generally cylindrical configuration into conformance with the interior walls of the main pipe. A pair of packers are disposed in the lined main pipe on opposite sides of the lateral pipe and a ball-like member with surface grooves is provided between the packers. Upon application of steam to the region between the packers, the steam raptures the side wall portion of the main liner, causing the ball to seat in the opening. Steam flow along the grooves at high velocity causes heat transfer to the abutting main and lateral liners to fuse the liners one to the other. Steam supplied through the grooves also reforms the lateral liner. In another form, the lateral liner and main liner may be fused together by electrofusion processes wherein electrical heating wires are provided on the flange. After fusion, a cutter cuts through the wise wall portion to form the opening between the lined main and lateral pipes.

Dependencies are inferred from the claim text.