Wild stress relief power supply apparatus
US4237369A · kind A · utility
Inventor
Key dates
| Filing date | Jan 31, 1979 |
| Grant date | Dec 2, 1980 |
| Priority date | — |
| Expiry date | Jan 31, 1999 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB23K9/235
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Temperature responsive power supply apparatus for electrical resistance heating, e.g. for weld stress relief, has a power supply transformer comprising first and second secondary windings in series with one another and first, second and third conductors for connecting the secondary windings to heating elements. A pair of temperature sensors provide temperature signals corresponding to the temperatures of heated zones heated by the apparatus, and a pair of control units responsive to the temperature signals control the current flow through the conductors. A switch enables one or both control units to regulate saturable reactors or the like in series with the conductors, whereby the control unit can regulate two respective heating circuits each including one of the secondary windings or one of the control units can regulate a heating circuit including one or both of the secondary windings. The apparatus provided improved versatility for heating one or more large or small pipe welds.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.