Lightweight, compact detector of sudden changes in concentration of a gas
US4761639A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 8, 1986 |
| Grant date | Aug 2, 1988 |
| Priority date | — |
| Expiry date | Oct 8, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N33/0063
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Lightweight, compact apparatus for detecting sudden changes in the concentration of at least one selected gas provides a warning when said gas concentration increases suddenly. In one embodiment, a chemically sensitive field effect transistor provides a sensing signal two amplifiers having different overall gains and widely different time constants. Detection of sudden gas concentration changes causes the relative magnitudes of the amplifier output signals to be inverted triggering a warning. The apparatus may occupy less than 1.25 cubic inches and weigh less than 4 ounces so that it may be worn by an individual throughout his work place.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.