Throttle cycle cryopumping system for Group I gases
US5687574A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 14, 1996 |
| Grant date | Nov 18, 1997 |
| Priority date | — |
| Expiry date | Mar 14, 2016 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S417/901
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A Group I gas cryopumping system includes a compressor throttle cycle refrigerator using mixed refrigerants. Cold refrigerant flows through a cryopumping surface located in a vacuum chamber, whereon vapor freezes. The refrigerant then passes through a heat exchanger in cross flow with refrigerant from the compressor. Refrigerant flow entering and leaving the heat exchanger is in uninsulated lines at substantially room temperature. All exposed cold lines are eliminated. The throttle device and cold cryopumping surface are an integral unit that connects directly to the flow paths of the heat exchanger without intermediate lines. The compressor/aftercooler unit may be located at any convenient distance from the heat exchanger and cryopumping surface, and the heat exchanger is located immediately adjacent to the pumping surface in a separate housing outside the vacuum chamber. The heat exchanger housing may share or be isolated from the vacuum of the vacuum chamber. Selected mixed refrigerants provide a wide range of cooling capacity over narrow, selectable temperature ranges. Thus, in a selected temperature range, gases are selectively collected to the exclusion of other gases. A tray…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.