Method of prestressing a tubular apparatus
US4538442A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 11, 1984 |
| Grant date | Sep 3, 1985 |
| Priority date | — |
| Expiry date | Jun 11, 2004 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49879
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A tubular apparatus is assembled of inner and outer tubes which are connected at spaced locations along their length. After heat treatment and other processing steps, either the inner or outer tube is heated to reduce its yield strength and then stretched beyond its yield point but not beyond the yield point of the other tubular. The heat source is removed so that the stretched state is maintained. The tubular apparatus is thus prestressed with the inner tube under compressive prestressing when the inner tube has been heated and stretched, and the inner tube under tensile prestressing when the outer tube has been heated and stretched.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.