Stop valve for a vacuum apparatus
US5172722A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 12, 1991 |
| Grant date | Dec 22, 1992 |
| Priority date | — |
| Expiry date | Sep 12, 2011 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/87499
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A stop valve for a vacuum apparatus comprises a valve casing having an inlet port and an outlet port, a main valve element housed in the valve casing for selectively opening and closing a flow passageway for causing the inlet port to comunicate with the outlet port, an auxiliary valve element for selectively opening and closing an orifice formed in the main valve element and capable of opening the flow passageway by opening the orifice when the main valve element is closed, a valve shaft for driving the main valve element and the auxiliary element, and a control mechanism for controlling the operation of the valve shaft and opening the main valve element after the auxiliary valve element has been opened.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.