Acoustic fire detection circuit responsive to microcapsule ruptures
AssigneeLa Detection Electronique Francaise Protecbat
InventorsDaniel Lecuyer, Anthonius H. Pietersen
Life of this patent
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Abstract
For the early detection of an abnormal rise in the temperature in an enclosure to be protected, a large number of micro-containers are arranged in the enclosure. These micro-containers are, for example, incorporated in the paint coating the walls of the enclosure. The micro-containers are filled with an extinguishing gas and produce when they burst a characteristic noise which is detected by microphones. The installation also comprises for the purpose of avoiding false alarms and achieving an adequate discrimination of the useful signal from that produced by the normal surrounding noise, a filtering and processing circuit which operates in an essentially digital manner.
Claims12
An installation for the early detection of a fire in an enclosure, comprising a plurality of noise producing means distributed in the enclosure and producing said noise upon an abnormal rise in the temperature in the enclosure, and an acoustic detecting circuit for detecting noise and setting off an alarm in the presence of said abnormal rise in temperature, said noise producing means being micro-containers each containing an extinguishing gas which has a vapour pressure capable of breaking the micro-container as a result of said rise in temperature and said detecting and alarm circuit comprises at least one microphonic transducer and a combined filtering circuit and digital processing circuit connected to the transducer for producing an alarm signal when the noise level produced by the bursting of the micro-containers reaches a predetermined level.
Dependencies are inferred from the claim text.