Multiple-gas NDIR analyzer
US5811812A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 1, 1996 |
| Grant date | Sep 22, 1998 |
| Priority date | — |
| Expiry date | Nov 1, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2201/0228
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A non-dispersive infrared (NDIR) multi-gas analyzer has an optical element that is positioned with respect to the axis of incident IR radiation such that it passes nearly all of the IR energy within a narrow band pass to one detector and reflects nearly all of the IR energy outside the narrow band pass to another detector. Thus, the optical element simultaneously functions both as a narrow band pass filter and a beam splitter, which transmits nearly all the IR energy within a band pass and reflects nearly all the IR energy outside the band pass. Additionally, the separation of the incoming energy can be achieved without an extended roll off. This allows using a reference transmission band that is very close to the absorption band of the gases of interest. It more specifically allows using a reference transmission band that is located between the absorption bands for hydrocarbons and carbon dioxide in an infrared analyzer that uses beam splitters.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.