Method and device for detecting gases by absorption spectroscopy
US7352463B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Sep 6, 2002 |
| Grant date | Apr 1, 2008 |
| Priority date | — |
| Expiry date | Oct 27, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2201/0668
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and device for measuring a concentration of a preselected gas in a gas sample are disclosed. The device comprises a Herriott type multipass cell (10) having a center axle (74) and a housing (80A, 80B) surrounding and spaced from the axle to provide a tubular sample cavity (84). The gas sample is pumped through the sample cavity via apertures (154, 156) provided in opposed ends of the axle. A first mirror (44) and a second mirror (46) are supported at opposed ends of the axle. A light source, e.g. a laser or LED, is provided for emitting a light beam into the sample cavity via an entry aperture (30) in the first mirror, the light beam having a wave length at which the preselected gas strongly absorbs. The beam is reflected between the mirrors for a number of times before exiting the cell via an exit aperture (48) in the second mirror and impinging on a detector (52). The device further comprises a reference detector (32) for monitoring the intensity of the unattenuated light beam and a detector for detecting the intensity of light transmitted through the second mirror after a single pass through the cell. The light source is operatively connected to a heat control assembly …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.