Method and system for detecting gases or vapors in a monitored area
US6061141A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 20, 1998 |
| Grant date | May 9, 2000 |
| Priority date | — |
| Expiry date | Jan 20, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/3504
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method of detecting the presence of a predetermined vapor of a predetermined concentration in a monitored area, the method including the steps of (a) exposing gas in or from the monitored area to radiation at wavelengths at least covering and surrounding from both sides a main absorption peak of the vapor; (b) simultaneously sensing the radiation after passing through the gas by a signal sensor and a reference sensor, each of the sensors including a radiation sensing element, wherein the signal sensor further includes a first optical filter passing wavelengths covering the main absorption peak, yet substantially blocking wavelengths from both sides of the main absorption peak of the vapor, whereas the reference sensor further includes a second optical filter passing wavelengths surrounding from both sides the main absorption peak, yet substantially blocking wavelengths covering the main absorption peak of the vapor; and (c) comparing signals obtained from the signal and reference sensors for determining a presence or absence of the vapor of the predetermined concentration in the gas.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.