Fluid monitor system and method using a resonator
US5455565A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 8, 1993 |
| Grant date | Oct 3, 1995 |
| Priority date | — |
| Expiry date | Nov 8, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2291/02433
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A non-invasive, fluid monitor engages an open resonator with a segment of fluid line. The fluid line is disposed such that it and the fluid within become a part of the dielectric loading on the resonator. The open resonator is a part of an oscillator circuit that changes frequency of oscillation in response to the dielectric loading on the resonator. A frequency discriminator monitors the frequency of the oscillator to detect an air bubble in the fluid line. In the case where the resonator comprises a microstrip line, the microstrip line is disposed in parallel to the segment of the fluid line and the length of the microstrip line is selected to be equal to or greater than the maximum length of air bubble permitted thus providing a volumetric air-in-line sensor. The output of the frequency discriminator is compared to a threshold to determine a frequency shift large enough to indicate the presence of an air bubble.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.