Process and apparatus for installing a new pipe inside an existing pipe

Abstract From the Canadian patent

or the Disclosure, A thermoplastic pipe in a flattened and folded configuration and of selected characteristics is formed either by manufacturing it in this reduced shape or by heating a round thermoplastic pipe enough to make it pliable and then reducing its cross sectional dimension. It is inserted in this reduced dimension and in a pliable state into a pipe to be rebuilt. It is then expanded and when set series as a rigid or semi-rigid pipe within a pipe capable of withstanding external hydrostatic and earth pressures. The thermoplastic pipe is heated during its installation for installing it in an exiting pipe and for expanding it. In a preferred process, the thermoplastic pipe upon …