Gas gauge proximity sensor with a modulated gas flow
US7021121B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 27, 2004 |
| Grant date | Apr 4, 2006 |
| Priority date | — |
| Expiry date | Sep 7, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B13/12
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A gas gauge proximity sensor modulates a gas stream that is used to feed reference and measurement air gauges, respectively, in a reference portion proximate a reference surface and a measurement portion proximate a measurement surface. The gas stream can be modulated at a frequency at which there is minimal acoustical interference energy (e.g., minimal noise) in demodulated output signal. The sensor output can be filtered so that a measurement signal includes only the modulated frequency and side bands of that frequency to include the desired response band of the device as a whole. The filtered signal can be demodulated using a demodulator operating at a same frequency as the modulator to produce the demodulated output signal. In this embodiment, substantially only ambient acoustical energy in the band pass region may interfere with the device operation. Alternatively, the modulation can be introduced through the reference portion. A reference nozzle sets up a pressure field with the reference surface. A carrier frequency can be generated by mechanical motion of the reference surface. For example, this motion can be introduced by a mechanism like a piezoelectric device or a voice …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.