| 摘要 |
The invention provides that an underground pipeline or passageway (10) is lined using a thermoplastic pipe. The pipe is extruded vertically downwards into a manhole (14) and then is fed into the pipeline or passageway (10) to be lined. The extrudate (34) is provided with longitudinal folds (38) so it will temporarily take up a reduced cross section. When in the pipeline or passageway (10) it is expanded up to size to line the pipeline or passageway (10) surface. It is kept hot and soft until it is expanded, when it is cooled so that it will retain its full size shape. |
