Fire detector
US4538137A · kind A · utility
23Cited by
4References
9Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Jan 20, 1983 |
| Grant date | Aug 27, 1985 |
| Priority date | — |
| Expiry date | Jan 20, 2003 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B17/11
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
In a fire detector that includes a sensor for producing an output voltage corresponding to smoke concentration, temperature, etc., there is provided a charge-and-discharge circuit to be reset by the turning ON of a switching circuit which is made ON at a fixed voltage. The output of the charge-and-discharge circuit and the output of a sensor are applied to the switching circuit to vary the ON period of the switching circuit corresponding to the output voltage of the sensor. Any irregularity in the sensor can be monitored by changes in the ON period.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.