Resistance heaters
US4754124A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 2, 1987 |
| Grant date | Jun 28, 1988 |
| Priority date | — |
| Expiry date | Mar 2, 2007 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D9/50
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A resistance heater for performing heat treatment of the braze-affected area of a metallic sleeve attached by brazing within and to a metallic tube, comprises a metal tube (10) of which a portion (16) is formed with a spiral groove (11) which penetrates the wall thickness of the tube (10) and thereby defines a heating coil. The radial thickness of the convolutions of the coil varies lengthwise of the coil so that, when energized with electrical current, the coil develops a temperature profile which is determined by the variation in radial thickness. The temperature profile may be selected according to the needs of the brazed joint to be heat treated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.