Combined method of determining fires
US5260687A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 2, 1992 |
| Grant date | Nov 9, 1993 |
| Priority date | — |
| Expiry date | Jan 2, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B29/185
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
First sensors measure physical quantities correlated with the heat release value of a fire source, and second sensors measure physical quantities correlated with the amount of the product of burning. At least a pair of one first sensor and one second sensor are arranged in a zone to be monitored. A first threshold of high sensitivity and a second threshold of low sensitivity are set at the first sensors. A third threshold is set at the second sensors. A pre-alarm is given only when the level of signals from the second sensors exceeds the third threshold. A fire alarm is given when the level of the signals from the second sensors exceeds the third threshold and when the level of signals from the first sensors exceeds the first threshold. The outputs from a plurality of such sensors detecting different objects, such as heat and smoke, are processed in the manner in which these outputs are combined together to reliably detect fires and to give a fire alarm. It is possible to improve the accuracy of detecting fires, and to reduce the incidence of false alarms.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.