Multilayer pipe and method for manufacturing one
US6959736B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jun 6, 2002 |
| Grant date | Nov 1, 2005 |
| Priority date | — |
| Expiry date | Nov 1, 2022 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/1393
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A multilayer pipe which comprises at least an inner layer and an outer layer. The inner layer is made of extrudable plastic, such as polyethylene PE, cross-linked polyethylene PEX or polypropylene PP. The outer layer forms a fire-protecting layer and the matrix plastic of the outer layer is also made of extrudable plastic. A foaming agent, which does not react during the manufacture of the pipe, is mixed with the matrix. Further, the outer layer contains at least one additive in such a manner that the outer layer has a pipe-reinforcing component and a fire-retardant component. Most preferably, at least the outer layer is extruded by an extruder having a screw length ratio of less than 10 to its biggest diameter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.