Cryopump with rapid cooldown and increased pressure
US4546613A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 20, 1984 |
| Grant date | Oct 15, 1985 |
| Priority date | — |
| Expiry date | Dec 20, 2004 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S417/901
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
In a cryopump, condensation of gases such as argon, oxygen and nitrogen on surfaces other than the second stage array 38, 40 is avoided to prevent cross over hang up and pressure instability. To prevent condensation of argon, oxygen and nitrogen on the frontal cryopumping array 46, that array is held to a temperature of at least 50.degree. K. A heat load to the first stage increases as the temperature of the first stage drops. That heat load is provided by a high emissivity radiation shield 44 or by a thermal switch 56, 58. Condensation of argon and other gases on the second stage refrigerator cylinder 32 is avoided by a close fitting sleeve 52 positioned over the refrigerator cylinder 32 in thermal contact with the second stage heat sink 30 but out of thermal contact with the cylinder 32.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.