Fire and explosion and detection suppression

• Main Authors: BALL; DAVID N, FARQUHAR; ROBERT L
• Format: Patent
• Language: English
• Published: 20.12.1983
• Subjects: ALARM SYSTEMS; ORDER TELEGRAPHS; PHYSICS; SIGNALLING; SIGNALLING OR CALLING SYSTEMS

The invention is for discriminating between the fire or explosion of an ammunition round and the fire or explosion which may then take place in the object struck by the round, and for initiating suppression of the latter fire or explosion only. Short wavelength radiation detectors feed a ratio detector which produces a logical output dependent on whether or not the color temperature of an event being monitored is above or below a fixed value. If the event is an exploding round then this will take the color temperature above this fixed value. A threshold unit and a rate of rise unit produce logical outputs dependent on whether the magnitude and rate of rise of the output of one of these two detectors are above or below fixed values. An infra-red detector detects radiation at a wavelength characteristic of a fire in the object; its output rises relatively slowly. If this detector detects a fire at this wavelength, it enables an AND gate but the gate does not initiate fire suppression if the ratio unit indicates that the color temperature is above the fixed value, because this signifies that the event is an exploding round. Fire suppression cannot take place until after the color temperature has fallen (and after a fixed delay produced by a monostable). The threshold unit and the rate of rise unit provide protection against incorrect initiation of fire suppression in conditions when the exploding round does not produce a color temperature clearly in excess of the fixed value.