Method and system for monitoring gas pressure for reference cavity of capacitance diaphragm gauge
US8997576B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 14, 2014 |
| Grant date | Apr 7, 2015 |
| Priority date | — |
| Expiry date | Jan 14, 2034 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01L21/34
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A system and method detect the presence of an unacceptable quantity of gas molecules in the reference vacuum cavity of a capacitance diaphragm gauge (CDG). An independent pressure transducer has an active portion exposed to the reference vacuum cavity. The transducer includes a ring anode, a cylindrical inner wall surface that forms at least one cathode, and a magnet positioned with respect to the ring anode such that the magnetic flux of the magnet is generally aligned with the central axis of the ring anode. A high voltage source applies a voltage between the ring anode and the cathode. A current sensor senses a magnitude of any current flowing between the ring anode and the cathode via ionized gas molecules. A monitoring unit monitors the magnitude of the current sensed by the current sensor and activates an alarm when the magnitude of the current exceeds an acceptable magnitude.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.