Heat exchanger tube repair
US4559436A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 4, 1984 |
| Grant date | Dec 17, 1985 |
| Priority date | — |
| Expiry date | Apr 4, 2004 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49352
- WIPO fieldThermal processes and apparatus
- WIPO sectorMechanical engineering
Abstract
Prior to effecting a repair of a leaking heat exchanger tube by an internal repair tube brazed to the leaking tube, strain in the leaking tube is measured while heating it to brazing temperature. A braze is only effected if the strain is below a predetermined level. Apparatus for carrying out the strain measurement typically of probe form having a strain gauge head (21) at the nose of the probe and a heater element (23). Preferably, the length of the probe is such that the head (21) reaches to just above a grid support plate (12). Where strain is found to be above said predetermined level and the leaking tube is of U-shape the strain may be relieved by heating both legs of the tube. Alternatively, strain may be relieved by thinning and bulging the leaking tube (FIGS. 5A-C) at a region close enough to the braze for the thinned zone to experience heat from the braze to allow it to yield under the strain.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.