Self-checking photoelectric smoke detector
US4306230A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 10, 1979 |
| Grant date | Dec 15, 1981 |
| Priority date | — |
| Expiry date | Dec 10, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01B13/0033
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A photoelectric smoke detector for providing indications of both alarm and trouble conditions is disclosed having a source of light, a detector apparatus having a light responsive device, said detector apparatus providing an output subject to a first change dependent upon the presence of smoke, the smoke detector further having a housing for mounting the source of light and the light responsive device, the housing having light path means for allowing light from the source of light to fall upon the light responsive device, the output from the detector apparatus being subject to a second change dependent upon trouble conditions, a first level sensor responsive to the first change to provide an alarm indication, and a second level sensor responsive to the second change to provide a trouble indication.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.