Method of installing a substantially rigid thermoplastic pipe in existing main and lateral conduits

摘要

A substantially rigid thermoplastic pipe for repairing a pipeline by installing the thermoplastic pipe in an existing underground pipeline, such as a service lateral, having access from only one end and a bend along its length is provided. The thermoplastic pipe may be manufactured in reduced form so as to have a memory for the reduced form, is heated to make it pliable for installation, and is pulled into the lateral from the access opening using a cable-and-pulley arrangement anchored temporarily at the intersection of lateral and main pipelines. When installed in a lateral, it is rounded and cooled in its rounded shape by passing steam under pressure through passages along the folds of the pipe while its leading end is restricted.