Pure steam-related apparatus protected from fouling and method of manufacturing the same
US6150040A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 14, 1998 |
| Grant date | Nov 21, 2000 |
| Priority date | — |
| Expiry date | May 14, 2018 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/12854
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A pure steam-related apparatus, which is one of apparatus in the group of pure steam generators generating pure steam from purified water, pipelines for pure steam and sterilizers using pure steam, is protected from discoloration, so-called "fouling", to red or black caused by contact with the pure steam. The apparatus is manufactured by using an austenitic stainless steel sheet as the material, by taking the blanks from the material which received no mechanical surface polishing, by deforming and welding, without electrolytic polishing customarily done, and by passivating the surface to contact pure water to increase Cr-content in the passivation film to such extent as 45 atomic % or higher, preferably 55 atomic % or higher. Better results will be obtained by ensuring Cr/Fe ratio in the passivation film at the level of 1.45 or higher, preferably, 1.70 or higher.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.