Pipe liner, a coiled liner product and methods for forming, installing and coiling the liner

摘要

A thermoplastic liner is extruded in cylindrical form and deformed at a temperature below the crystallization temperature of the polyethylene material forming the liner into a generally W-shaped configuration. The liner in that configuration has three convex lobes and two concave lobes along one side of the liner with a convex portion of the liner wall along the opposite side. The cylindrical liner is initially extruded in cylindrical form and deformed by a series of axially spaced sets of rollers progressively inclined toward a vertical position wherein the final W-shaped configuration of the liner is formed. The liner has a cross-section in any direction less than one-half of the diameter of the liner when expanded into a cylindrical configuration. The deformed liner is coiled about a reel. At an installation site, the liner is pulled from the reel through the pipe and sealed at opposite ends. Steam under pressure expands the W-shaped liner to a cylindrical configuration to line the pipe.