Manufacture of plastic jacketed steel pipe
US4904323A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 15, 1988 |
| Grant date | Feb 27, 1990 |
| Priority date | — |
| Expiry date | Sep 15, 2008 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T156/1013
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Making jacketed pipe using metal strip coated with a plastic coating compatible with the jacket material. After the strip is formed into tube by turning over longitudinal edges of the strip, the jacketing material is then extruded onto the tube under an extrusion pressure insufficient to cause tube collapse. This is conveniently done by the known "tubing" process. Subsequent to the extrusion step, the jacket material is subjected to radial inward pressure also insufficient to cause tube collapse. This pressure reduces the outside diameter of the jacket and presses it against the coating on the tube. The inward pressure step is performed while residual heat from extrusion remains at the inner surface of the jacket to fuse the jacket to the plastic coating. Inward pressure is preferably applied by a polishing die.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.