Method of making plastic pipes having walls with lengthwise extending channels
US4390383A · kind A · utility
25Cited by
7References
9Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Mar 25, 1981 |
| Grant date | Jun 28, 1983 |
| Priority date | — |
| Expiry date | Mar 25, 2001 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T156/1005
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Plastic pipes comprising an inner and outer wall being interconnected by lengthwise extending connecting partitions, forming channels, the ends of the channels being each separately sealed by sealingly pressing the end walls of a channel to each other after these walls have been heated to a temperature surpassing the plasticizing temperature.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.