FIRE SENSOR FOR AUTOMATIC FIRE ALARM SYSTEMS, AND AUTOMATIC FIRE ALARM SYSTEM USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a fire sensor for automatic fire alarm systems that enables the master machine to restrain misrecognition of fire alarm, and an automatic fire alarm system using the fire sensor.SOLUTION: A transmitting unit 101, electrically connected to paired electric wires 51 and 52 to which voltages are applied, transmits fire alarm and linked alarm. A voltage detecting unit 3 detects a voltage V5 between the paired electric wires 51 and 52. A control unit 4 controls the transmitting unit 101. The transmitting unit 101 draws in the current flowing to the paired electric wires 51 and 52, and transmits fire alarm, keeping the voltage V5 between the paired electric wires 51 and 52 not below a second reference voltage and not above a first reference voltage. The transmitting unit 101 transmits linked alarm, keeping the voltage V5 between the paired electric wires 51 and 52 below the second reference voltage. The control unit 4 does not allow fire alarm to be transmitted from the transmitting unit 101 if the voltage V5 between the paired electric wires 51 and 52 is not above the first reference voltage on the basis of the result of detection by the voltage detecting unit 3.SELECTED DRAWING: Figure 2