Process and apparatus for heat treating articles while hardening in gaseous medium
US5158625A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 4, 1991 |
| Grant date | Oct 27, 1992 |
| Priority date | — |
| Expiry date | Apr 4, 2011 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D1/773
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Process for heat treating articles by hardening them in a recirculating gas medium which is in contact with the treated articles, the hardening gas being cooled by means of a heat exchanger, of the type in which helium is used as hardening gas, and is stored under holding pressure in a buffer container, wherein at the end of a hardening operation, a helium load is extracted from the treatment enclosure, in final phase by means of pump until a primary vacuum is obtained, the extracted helium is brought to purifying pressure by means of a compressor associated to a mechanical filter, and the helium under purifying pressure is sent to a purifier in which impurities are removed, after which it is transferred, if desired, after recompression in the buffer container.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.