Non-stressed, high strength, cement-containing pipe and its production
US4077577A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 4, 1976 |
| Grant date | Mar 7, 1978 |
| Priority date | — |
| Expiry date | Feb 4, 1996 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16L9/16
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Non-stressed, high strength, substantially inflexible, rigid, cement-containing pipe, for example, asbestos-cement pipe well adapted as high pressure water pipe, comprising a tubular article body of spirally wound up layers of asbestos-cement, and a plurality of helical windings of a continuous filament of an aromatic polyamide fiber known and obtainable as KEVLAR aramid fiber about one or more of the asbestos-cement layers within the interior of the pipe without being stretched and without being in tension. The aromatic polyamide fiber of the continuous filament is of high tensile strength of about 390,000 psi or higher and a low elongation capability of no more than 7%, and the continuous filament of the belical windings is maintained about the cement-containing composition within the interior of the pipe without being stretched and without being in tension. Non-stressed, high strength concrete pipe is also embodied in the invention. The outer exposed main surface of the pipe is usually free or substantially free of the continuous filament.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.