Apparatus for deforming plastic tubing for lining pipe
US4998871A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 19, 1989 |
| Grant date | Mar 12, 1991 |
| Priority date | — |
| Expiry date | Jan 19, 2009 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C67/0014
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Apparatus is provided for lining a pipe wherein a thermoplastic liner is initially formed in a cylindrical shape with a diameter slightly larger than the internal diameter of the pipe. The liner is temporarily deformed at an elevated temperature to a different cross-section, preferably U-shaped, to reduce its overall cross-sectional dimension to facilitate insertion into the pipe to be lined. The deformation occurs with substantially comparable elongation of the pipe lining along its opposite sides thereby precluding variations in wall thickness and stress in the pipe. Once inserted, the liner is pressurized and reheated first to a temperature below its crystallization temperature to round the lining in the pipe and subsequently, further pressurized and reheated to a second temperature higher than the crystallization temperature to cause the liner to retain its original round shape.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.