Apparatus including a capacitive probe for measuring the level and/or the volume of a liquid
US5052223A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 30, 1990 |
| Grant date | Oct 1, 1991 |
| Priority date | — |
| Expiry date | May 30, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01F23/263
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The present invention relates to apparatus for measuring the level and/or the volume of liquid contained in the tank. The apparatus being of the type comprising a capacitive probe including at least two generally vertical parallel separate main plates for immersing in the liquid, and capacitance-measuring means having a detection input and a ground, the detection input being connected to a first one of the main plates and the ground being connected to the second main plate, wherein the first plate is surrounded by a guard ring. Furthermore, the present invention measures the level or volume of a liquid by calculating a coefficient K using the expression K=(Cmes-Cair)/(Cimm-Cair); in which Cmes is the measuring capacitance between the first and second plates; Cair is the capacitance of the first plate and the second plate in air; Cimm is the capacitance of the first plate and the second plate when they are totally immersed; and K is defined as the area of the first plate in the liquid divided by the total area of the first plate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.