Flow control system
US5000221A · kind A · utility
Inventor
Key dates
| Filing date | Sep 11, 1989 |
| Grant date | Mar 19, 1991 |
| Priority date | — |
| Expiry date | Sep 11, 2009 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/7822
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
To control the flow of a fluid from an environment to a vacuum source, a device including a piston (2) is mounted in the path of the fluid. The path is not vented so that the mass of fluid entering the device is equal to the mass exiting the device. The piston (2) is mounted so that it may constrict the path at a constriction point (5), and so that it may move in a direction (14) transverse to the flow of the fluid at the constriction point (5). The frontal face (15) of the piston (2) is exposed to the fluid in the path, and the distal face (16) of the piston (2) is exposed to a reference pressure (17). A restoring force, such as a spring (10) or the weight of the piston (2) is exerted on the piston (2) so as to tend to widen the path at the constriction point (5).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.