Fire detector utilizing two bandwidths of radiation
US4119949A · kind A · utility
6Cited by
3References
3Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Mar 22, 1977 |
| Grant date | Oct 10, 1978 |
| Priority date | — |
| Expiry date | Mar 22, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B17/103
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
An optical fire detector has a radiation-emitting means which emits a beam of radiation which, after passing through an intermediate air-medium is received by a radiation detecting means for providing an alarm upon an obscuration of the beam or radiation. The radiation-detecting means has first means for individually measuring the intensity in a first and a second wave-length band of the beam of radiation and second means for comparing the invididually measured intensities to provide the alarm upon a predetermined difference between such intensities.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.