Thermal gas sensing apparatus
US5897836A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Dec 19, 1996 |
| Grant date | Apr 27, 1999 |
| Priority date | — |
| Expiry date | Dec 19, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N27/185
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A thermal gas sensing apparatus for a gas detector is provided with a gas compartment containing a gas, a gas sensor exposed to the gas in the gas compartment, and a temperature sensor exposed to the gas in the gas compartment. The gas sensing apparatus includes a circuit for generating a gas signal having a magnitude which relates to the heat capacity of the gas and a circuit for generating a temperature signal having a magnitude which relates to the temperature of the gas. The apparatus includes a circuit for supplying a variable magnitude of electrical current through the gas sensor to cause the resistance of the gas sensor to remain substantially constant. The apparatus also includes a difference amplifier for generating a gas concentration signal based upon the temperature signal and the gas signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.