Fire alarm system
US4881060A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 16, 1988 |
| Grant date | Nov 14, 1989 |
| Priority date | — |
| Expiry date | Nov 16, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B29/22
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
An improved alarm system and method for use in a fire detection system of the type including at least one sensor for sensing the level of a parameter of a fire condition such as heat or smoke density and which transmits electrical signals indicative of the sensed levels over a communication link. The alarm system and method provides for indicating a first alarm condition by receiving electrical signals from the sensor, keeping time from the time that the parameter reaches a first level, and indicating the first alarm condition when the parameter reaches a second level within a first predetermined time period. The second level has a magnitude greater than the first level. The alarm system and method also indicates a first alarm condition corresponding to a third level of the parameter prior to the third parameter level being reached. A clock keep time from the time that the parameter reaches the first level and alarm means indicates the first alarm condition when the parameter reaches the second level from the first level within a first predetermined time period. The second level has a magnitude greater than the first level and less than the third level.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.