Apparatus for detecting the presence of a specific substance in a gas stream
US4181699A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 7, 1978 |
| Grant date | Jan 1, 1980 |
| Priority date | — |
| Expiry date | Mar 7, 1998 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/8483
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An apparatus for detecting the presence of a specific substance in a gas stream is disclosed. The apparatus comprises a sensing chamber adapted to receive a test paper which is subject to coloration when contacted by a specific substance in a gas contained in the sensing chamber, means for generating a light beam and directing it toward the test paper in the sensing chamber, a light beam sensing device responsive to the extent to which the test paper in the sensing chamber undergoes coloration in response to exposure to the specific substance in the gas stream, an amplifier connected to the light beam sensing device for providing an output voltage which is proportional to the coloration of the test paper, and means connected to the amplifier for providing an output signal which is an instantaneous indication of the concentration of the substance to be monitored, comprising a signal conditioning circuit connected to the amplifier for providing an output which is a linear function of the cumulative amount of the substance to be detected contacting the test paper, and a differentiator responsive to the output of said amplifier for deriving the instantaneous concentration of the substa…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.