Method and apparatus for detecting a component gas in a sample
US5184017A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 19, 1991 |
| Grant date | Feb 2, 1993 |
| Priority date | — |
| Expiry date | Aug 19, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2201/1285
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A non-dispersive infrared gas analyzer especially adapted for measuring the concentrations of HC, CO and CO.sub.2 in a vehicle exhaust includes a sample chamber for holding a sample gas, a radiation emitter for directing a beam through the chamber and a detector for indicating the amount of radiation absorbed. A plurality of filters each of which transmit radiation at an absorption band of a gas component to be detected are alternatingly positioned in the radiation path to produce a time-multiplexed signal having concentration information for all gases. The time-multiplexed detector output is corrected for gain and offset errors "on-the-fly", without requiring demultiplexing, through the use of an analog multiplier circuit. The correction factors are themselves determined without demultiplexing the detector output signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.