| 摘要 |
PROBLEM TO BE SOLVED: To provide a fire detector that can reduce false alarms and alarm failures in a structure in which fire occurrence is determined, according to the attenuation of ultrasonic waves in a monitored space. SOLUTION: The fire detector comprises a monitoring sound source part 1 capable of transmitting ultrasonic waves to a monitored space Sp1 communicating with an external space and accessible to suspended particles containing smoke particles from the external space; a reference sound source part 10 capable of transmitting an ultrasonic wave to a reference space Sp2 inaccessible to suspended particles containing smoke particles; a control part 2 for controlling the monitoring sound source part 1 and reference sound source part 10; a monitoring wave receiving element 3 for detecting the sound pressure of the ultrasonic waves transmitted from the monitoring sound source part 1; a reference wave receiving element 30 for detecting the sound pressure of the ultrasonic waves transmitted from the reference sound source part 10; and a signal processing part 4 for determining whether there is a fire according to the output of the monitoring wave receiving element 3 and reference wave receiving element 30. The signal processing part 4 has an output correction means 40 for correcting the output of the monitoring wave receiving element 3, based on the rate of change in the output of the reference wave receiving element 30 from the initial value. COPYRIGHT: (C)2009,JPO&INPIT
|
