JPH0624953Y2 - Fire alarm - Google Patents

Description

[Detailed Description of the Invention] [Industrial application] The present invention relates to a fire alarm device, and more particularly to a fire alarm device capable of detecting falling of a fire detector.

[Prior Art] Conventionally, as a fire alarm device in which a plurality of fire detectors are connected to a pair of lines extending from a receiver, a fire alarm device that constantly monitors disconnection of the pair of lines has been put into practical use. Among such line monitoring methods, there is a method in which a capacitor is connected to a terminating element, a pair of line power sources is intermittently cut off, and the disconnection state is detected from the voltage or discharge current between the lines at that time. For example, Japanese Utility Model Publication No. 57-38777, "Fire alarm equipment disconnection detection circuit", and Japanese Patent Application Laid-Open No. 57-48191, "Fire alarm device" are available.

In addition, by using the detector base that becomes conductive when the fire detector is connected and becomes non-conductive when the fire detector is dropped, make the drop of the fire detector the same state as the disconnection state and There is a device that detects the dropout. For example, there is Japanese Utility Model Publication No. 54-24622 “Fire detector drop detection device”.

[Problems to be solved by the invention] In this way, when the fire detector is dropped and the drop is detected in the same state as the disconnection state, the signal line with the subsequent fire detector is cut from the dropped portion. Therefore, there is a drawback that this part cannot be monitored by the fire detector.

[Means for Solving the Problem] The fire alarm device of the present invention is connected to a plurality of fire detectors which are conducted at a low impedance when a fire phenomenon is detected, and when the fire detectors are connected, they are conducted and dropped. A sensor base provided with two terminals that become non-conducting, a pair of lines sent and wired through the two terminals of the sensor base, and a capacitor connected to the ends of the pair of lines. , A power supply which is intermittently cut off between the pair of lines, and the operation of the fire detector and the disconnection of the pair of lines are detected from a change in the current or voltage of the pair of lines to receive an alarm display. And a diode connected in a forward direction with respect to a power source between two terminals of the sensor base.

[Embodiment] An embodiment of the fire alarm device of the present invention will be described below with reference to the drawings.

The drawing is a circuit block diagram showing an embodiment of the fire alarm device of the present invention.

This fire alarm device includes a receiver 1, a pair of lines 4,5 extending from the receiver 1 to a warning area, and a plurality of sensor bases 31 to 31 for sending and wiring the pair of lines 4,5.
3n, the plurality of fire detectors 21 to 2n connected to the plurality of detector bases 31 to 3n, and the detector bases 31 to 31n.
It is composed of diodes 61 to 6n connected in the forward direction to the power source of the receiver 1 between the two terminals 3b and 3c of 3n.

The receiver 1 includes a DC power supply 10 and fire detectors 21 to 2n.
A relay 11 that is energized during operation of the relay 11, a fire alarm 14 connected to a normally open contact 12 of the relay 11, and a switch circuit 13 that intermittently cuts off power supply to the pair of lines 4 and 5. A detection circuit 15 that detects the disconnection state of the lines 4 and 5 from the voltage between the pair of lines 4 and 5 or the discharge current from the terminating capacitor 7 in synchronization with the switching circuit 13 being cut off.
And an alarm device 16 for a failure alarm driven by the detection signal (failure signal) of the detection circuit 15.

When the fire detectors 21 to 2n are normally connected to the detector bases 31 to 3n, the terminals 3b and 3c are electrically connected, and when they are not connected (when they are disconnected), they are in a non-conductive state.

To explain the operation of the fire alarm device thus configured, normally, the pair of lines 4 and 5 are normally wired, and the fire detectors 21 to 2n are normally connected to the detector bases 31 to 3n. In this case, the termination capacitor 7 is charged with a predetermined voltage by the power source supplied to the pair of lines 4 and 5. The voltage between the pair of lines 4 and 5 does not fall below a predetermined level due to the charge stored in the capacitor 7 even while the power source 10 is shut off by the switch circuit 13. Further, the discharge current flows through the internal resistance of the detection circuit 15. In such a state, the detection circuit 15 judges that it is in a normal state and outputs no signal. Then, if there is a disconnection in the pair of lines 4 and 5 or if any of the fire detectors 21 to 2n falls off from the detector bases 31 to 3n, the voltage or current due to the charge charged by the terminating capacitor 7 is not detected when the power is cut off, so the detection circuit. 15 detects this and outputs a failure signal to the alarm device 16. In this way, the pair of tracks 4,
The disconnection of 5 and the fall of the fire detectors 21 to 2n are monitored.

When any of the fire detectors 21 to 2n detects heat, smoke, etc. of a fire phenomenon, it conducts with a low impedance and the detector base 31
.. 3n terminals 3a, 3b (3c) are electrically connected, an operating current flows through the pair of lines 4, 5, and the relay 11 is energized. The normally open contact 12 of the relay 11 is closed to supply power to the alarm device 14 to drive the alarm device 14 to display a fire alarm.

If the fire detectors 21 to 2n are detached from the detector bases 31 to 3n (contact failure, forgetting to connect detectors, etc.),
Power can be normally supplied to the fire detectors 22 to 2n subsequent to this drop-off point through the diodes 61 to 6n-1 connected to the detector bases 31 to 3n at the drop-off point, and the monitoring state can be maintained. Further, in such a state, since the diodes 61 to 6n are in the opposite directions with respect to the discharge current of the terminating capacitor 7, the state becomes the same as the disconnection state and a failure is displayed.

[Effects of the Invention] As described above, the fire alarm device of the present invention detects the fall of a fire detector and normally supplies power to the subsequent fire detector from the place of fall when it falls. It has the effect of maintaining the monitoring status by using this method, which is extremely useful for disaster prevention.

[Brief description of drawings]

The drawing is a circuit block diagram showing an embodiment of the fire alarm device of the present invention. 1 ... Receiver, 21-2n ... Fire detector, 31-3n ... Detector base, 4, 5 ... Line, 61-6n ... Diode,
7 ... Capacitor, 10 ... DC power supply, 11 ... Relay, 12
... normally open contact of relay 11, 13 ... switch circuit, 14,
16 ... Alarm device, 15 ... Detection circuit.

Claims (1)

[Scope of utility model registration request] 1. A plurality of fire detectors that conduct with a low impedance when a fire phenomenon is detected, and two terminals that conduct when the fire detectors are connected and become non-conducting when dropped. A sensor base, a pair of lines that are sent and wired via two terminals of the sensor base, a capacitor connected to the ends of the pair of lines, and intermittently cut off between the pair of lines. Between the two terminals of the detector base and the receiver that supplies power and detects the operation of the fire detector and the disconnection of the pair of lines from the change in the current or voltage of the pair of lines, and displays an alarm. A fire alarm device comprising a diode connected in a forward direction with respect to a power source.