Bidirectional vacuum valve
US5174335A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 30, 1992 |
| Grant date | Dec 29, 1992 |
| Priority date | — |
| Expiry date | Apr 30, 2012 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/86936
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
To evacuate a vacuum chamber without stirring up particles in the chamber or associated piping, a pneumatically-actuated vacuum valve is used between the chamber and the vacuum pump. The valve controls evacuation in two stages: in the first stage, the valve partially opens, and a skirt with leak vents in it is brought into play so that air is drawn slowly through the leak vents to gradually achieve a vacuum of a few Torr without stirring up particles; in the second stage, the valve fully opens, and the remaining air in the chamber can be drawn out efficiently, utilizing the large diameter of the valve fully, without risk of stirring up particles. The actuation of the valve is controlled by a timer, which dictates how long the valve stays in the partially-open state before switching to the fully-open state.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.