Method of and apparatus for manufacturing a plastic pipe comprising longitudinally extending hollow channels in its wall
US4321228A · kind A · utility
31Cited by
8References
8Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Mar 25, 1980 |
| Grant date | Mar 23, 1982 |
| Priority date | — |
| Expiry date | Mar 25, 2000 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29L2031/60
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Method and extruder for manufacturing plastic pipes provided with longitudinal channels in its wall. Before the extrusion nozzle of the extruder, the stream of plastics to be extruded for forming the pipe is subdivided into two concentric annular streams flowing through two annular division channels formed by means of a dividing member being retained by only a breaker in the outer division channel, the other division channel forming a free passage between the channel inlet and the outlet.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.