Saturation filtering NDIR gas sensing methodology
US8003944B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Apr 13, 2010 |
| Grant date | Aug 23, 2011 |
| Priority date | — |
| Expiry date | Apr 13, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2201/0231
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
NDIR gas sensing methodology is advanced which renders the output of an NDIR gas sensor, when implemented with this new methodology, to remain stable or drift-free over time. Furthermore, the output of such a sensor will also be independent of the temperature of an environ wherein the sensor is in physical contact. This method utilizes the same narrow band-pass spectral filter for the detection of the gas of interest for both the signal and the reference channels. By so doing, the two channels always receive radiation of the same spectral content from the infrared source of the sensor convoluted with that from any external elements exposed to the sensor. While the same sample chamber through which the gas of interest to be detected flows is shared by the two channels, the detector package for the reference channel is hermetically sealed with 100% of the gas to be detected instead of 100% N2 as for the signal detector. In so doing, the reference channel is rendered almost completely “blind” to the presence or absence of the gas of interest flowing in the common sample chamber thereby creating an absorption bias or difference between the two channels enabling the concentration of the…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.