Time delay control and system embodying same
US4844798A · kind A · utility
Inventor
Key dates
| Filing date | Oct 13, 1988 |
| Grant date | Jul 4, 1989 |
| Priority date | — |
| Expiry date | Oct 13, 2008 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/86413
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A fluid-operated, time delay control and system embodying same are set forth. The time delay control includes an accumulator chamber communicating with a source of fluid under negative pressure or vacuum and a second chamber having a partition dividing it into two parts, a first of which communicates with the accumulator chamber. The second part communicates with a vacuum-sensitive switch which is energized when sensing a vacuum of a predetermined value. The partition has a check valve for maintaining the vacuum switch in communication with a vacuum after the vacuum is released at the source and the pressure rises in the first part of the second chamber. An adjustable flow control valve in the partition slowly releases the vacuum which the switch senses. The switch then reverts to a de-energized condition when a predetermined value is reached. A filtering system incorporates the time delay control with the control controlling a vacuum break valve and a motor for moving a strip of filter media.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.