Apparatus for monitoring the level of liquid in a tank or reservoir
US4558456A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 27, 1982 |
| Grant date | Dec 10, 1985 |
| Priority date | — |
| Expiry date | Sep 27, 2002 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01F23/243
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Apparatus for monitoring the level of liquid in a tank or reservoir comprises a probe formed by a resistive metal element having a high temperature coefficient, and a supply means for the probe. The apparatus further comprises a voltage-frequency converter which is connected in parallel with the probe, two counters which are connected in parallel to the output of the converter, and a subtracting means connected to the outputs of the counters. A time base controls operation of the supply means during a complete cycle to effect a counting operation of the first counter for a given period of time at the beginning of a cycle, a counting operation of the second counter for the same period of time but at the end of the cycle, and operation of the subtracting means at the end of the cycle.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.