High accuracy calibration-free electrical parameter measurements using differential measurement with respect to immersion depth
US5489849A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 14, 1994 |
| Grant date | Feb 6, 1996 |
| Priority date | — |
| Expiry date | Mar 14, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N27/02
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An apparatus and method for measuring electrical parameters of a medium such as electrical conductivity and dielectric constant between a pair of electrodes are disclosed. The medium can be a liquid, gas, powder, etc., and the electrodes can be coaxial metallic circular cylinders. To compute electrical conductivity, the device is immersed in the medium to an immersion depth and the conductance across the electrodes is determined. The measurement is repeated at at least one additional immersion depth. By obtaining a differential conductance measurement with respect to the immersion depth, the effects of fringe conductances are eliminated from the measurement. The device can also be used to determine dielectric constant of the material by obtaining a differential capacitance measurement with respect to immersion depth. The device need not be calibrated by performing resistance measurements in a known standard solution. Also, because the electrodes can be purely metallic and include no dielectric material, the device can be used to perform measurements in highly corrosive media whose compositions would be altered upon contact with dielectric materials.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.