Enclosed pump switch level control system
US7578657B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 18, 2003 |
| Grant date | Aug 25, 2009 |
| Priority date | — |
| Expiry date | Aug 12, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01H35/18
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An arrangement (10) for controlling the liquid level in a basin (60) by selectively actuating a pump (64) has an environmentally-sealed enclosure (22) with an internal volume subject to thermal and pressure effects. A first (14) and a second (16) pressure sensing means are positioned in the enclosure and a barrier fluid (18) fills a balance of the internal volume. The first sensing means (14) is in a first chamber (22a) of the enclosure (22) and the second sensing means (16) is in a second chamber (22b). The barrier fluid (18) has a first portion (18a) in the first chamber (22a) and a second portion in the second chamber (22b). The first pressure sensing means (14) communicates an “on/off” signal to the pump (64). Diaphragms (26, 40) in the respective chambers (22a, 22b) allow the device to adjust to changes in atmospheric pressures. The barrier fluid (18) is electrically non-conductive, chemically non-reactive with any materials comprising the pressure sensing means and, preferably, an oil.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.