Auto-compensating capacitive level sensor

US6539797B2 · kind B2 · utility

Assignee

• BECS TECHNOLOGY, INC. · US

Inventors

• Richard Livingston · Webster Groves, US
• Roger D. Chamberlain · Chesterfield, US

Key dates

• Filing date: Jun 25, 2001
• Grant date: Apr 1, 2003
• Expiry date: Jun 25, 2021

Classification

• Technology area (CPC G): Physics
• CPC primary: G01F23/268
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A capacitive sensor array is adapted to be disposed in a reservoir containing fluid or material along an axis of measurement of the fluid or material to determine the level of fluid or material contained within the reservoir. The sensor array includes a plurality of reference electrodes, wherein the capacitance of each of the electrodes varies in accordance both with the extent of the array's immersion in the fluid or material and the dielectric constant of the fluid or material. The plurality of reference electrodes preferably includes a lower electrode adapted to be immersed within the fluid or material in the reservoir and whose capacitance provides an estimate of the dielectric constant of the fluid or material contained within the reservoir. The reference electrodes also include an upper electrode adapted to be positioned above the fluid or material level that provides an estimate of the dielectric constant above the level of the fluid or material in the reservoir, and a middle electrode whose capacitance varies from a calibrated initial value to a value that is dependent on the level of and the dielectric constant of the fluid or material contained within the reservoir as det…