Unidirectional capacitive fluid-gauging systems
US4525792A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 10, 1983 |
| Grant date | Jun 25, 1985 |
| Priority date | — |
| Expiry date | Mar 10, 2003 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01F23/266
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A fuel-gauging system has a capacitive probe mounted in a fuel tank and supplied with an alternating voltage V.sub.s from a drive unit. The output of the probe is rectified by a diode mounted in the tank, prior to supply to a measuring unit. The voltage V.sub.D across the diode varies with temperature and is measured periodically by reducing the input voltage V.sub.s by a known factor X. The voltage V.sub.D is calculated by the measuring unit from the two output currents I.sub.1 and I.sub.2 produced respectively at the two different voltages V.sub.s and V.sub.s /X. The capacitance and hence the depth of fluid is calculated using the known voltage V.sub.D across the diode. The drive unit has a transformer that is used to reduce the voltage periodically by switching between different tappings of its secondary windings.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.