JPH0340631B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an automatic fire alarm system, and more particularly to a fire alarm system equipped with a circuit breakage automatic recovery device.

(Conventional technology) The content of automatic fire alarm equipment is based on the Fire Service Act.
It is decided based on the size of the building, its purpose, etc., but there is little consideration given to the equipment or work inside the building. Therefore, depending on the equipment inside the building or the nature of the work, the same conditions that trigger a fire detector may occur.
False alarms are common in such buildings. Moreover, the frequent occurrence of false alarms creates a wolfish atmosphere towards alarms, fosters distrust of automatic fire alarm equipment, and invites tragedy in the event of an emergency.

This invention addresses matters that cause false alarms.
This proposal was made from the standpoint of proactively responding to this issue if possible.

That is, in factories, workshops, etc., the use of fire, opening of furnaces, cleaning with hot water, etc. may cause the indoor temperature to temporarily rise rapidly, causing a fire detector to be activated. In such a case, the sensor circuit at the site is cut off before the work begins to stop alarms from being issued throughout the building.

However, if the circuit is completely cut off, it will not be possible to detect a fire after the work is completed.
Above all, it is absolutely necessary to avoid a situation where the fire detector circuit is left cut off for longer than necessary, whether temporarily or intentionally.

(Problems to be Solved by the Invention) In view of this situation, the device of the present invention has a backup alarm circuit in the cut-off fire alarm circuit and a circuit that automatically returns to the original fire alarm circuit as time passes. By providing this, the above-mentioned conventional problems are attempted to be solved.

(Means for Solving the Problem) That is, the present invention provides a cutoff circuit in a fire alarm circuit that connects a fire detector and its receiver,
When the cutoff circuit is activated, the fire alarm circuit is cut off to connect the fire detector and a preliminary alarm circuit that senses a fire signal from the fire detector and issues a preliminary alarm, and the cutoff circuit This invention relates to an automatic fire alarm device characterized in that the circuit stops operating after a predetermined cut-off time has elapsed and automatically returns to the fire alarm circuit.

(Example) Hereinafter, an example will be described in detail according to the attached drawings. Fig. 1 is an overall block diagram of an automatic fire alarm system showing an example of the device of this invention, and Fig. 2 shows its operation. It is a frochart diagram.

The fire detectors 1, 1, . . . installed at various locations shown in the upper left of FIG. 1 are connected to the receiver 2 shown in the lower left of the figure to form a fire alarm circuit, thereby configuring an automatic fire alarm system.

However, in the device of this invention, the fire alarm circuit connecting the fire detector 1 and the receiver 2 is cut off, and a preliminary alarm circuit and a timer automatic reset circuit are interposed as shown to the right of the chain line in the figure. It has particular characteristics.

In the figure, reference numeral 10 indicates a cutoff circuit for interrupting the fire alarm circuit, 20 indicates a fire signal receiving circuit for a preliminary alarm circuit, 30 indicates a preliminary alarm circuit, 40 indicates a starting and recovery circuit for a timer automatic recovery circuit, 50 is also an early recovery alarm timer circuit;
Reference numeral 60 similarly indicates the time advance alarm circuit, 70 indicates a cutoff time timer circuit, 80 indicates a cutoff time display circuit, and 90
Reference numeral 100 indicates a power supply circuit, and 100 indicates a test switch fast-forward circuit.

First, when the set switch 41 of the starting circuit 40 is pressed, the fire alarm circuit connecting the fire detector 1 and the receiver 2 is cut off by the relay 11 of the cutoff circuit 10.

As shown in FIG. 1, the relay 11 is a change-over type switch, and connects each fire detector 1 to the backup alarm circuit 30 at the same time as cutting off the main fire alarm circuit.

This preliminary alarm circuit 30 has its own fire signal receiving circuit 20, which is activated upon sensing the fire signal from the fire detector 1, and issues an appropriate preliminary alarm such as a lamp or a buzzer.

As is clear from the operation flowchart in Figure 2, the cut-off time timer circuit 70 is activated at the same time as the switch that activates the cut-off circuit is turned on, and the cut-off time set in the timer is digitally displayed, and the cut-off time is also displayed. The circuit 80 displays the remaining time as time passes.

Then, before the predetermined cut-off time expires by the early recovery alarm timer circuit 50,
For example, when the time for an early warning comes 5 to 10 minutes in advance,
A signal is input to the pre-time alarm circuit 60 and an alarm such as a buzzer is emitted. Although this alarm can be stopped, for example, by pressing a stop button, the time continues to elapse and the circuit is restored to its original state when the predetermined cut-off time expires.

If you wish to extend the cutoff time, press the set switch 41 again to return to the initial set time.
Further, even during the cut-off time, the reset switch 42 can restore the circuit to its original state. Furthermore, the test switch of the fast-forward circuit 100 is designed to fast-forward a set time to test its operation.

(Function/Effect) As explained above, the device of the present invention interrupts the fire alarm circuit in automatic fire alarm equipment and connects it to the preliminary alarm circuit, and also detects the fire alarm after a predetermined cut-off time has elapsed. Since the device is equipped with a cutoff circuit that automatically returns to the fire alarm circuit, it prevents false alarms and maintains confidence in the automatic fire alarm system, and also prevents the alarming situation of leaving the cutoff state unattended by automatic recovery using a timer. It has now become possible to significantly improve the functionality of automatic fire alarm systems.

In addition, in the device of the invention, even if the main fire alarm circuit is cut off, each fire detector 1 is connected to the backup alarm circuit 30, so the fire detectors placed at various locations can operate normally. You can confirm that it works. Furthermore, even during the time when the main fire alarm circuit is cut off, it is not impossible for this alarm to be activated due to a fire. More than anything,
Even if the circuit of the fire alarm system is cut off, it is significant that the backup alarm system is still operating.

As described above, the present invention is extremely effective, particularly in buildings and facilities such as factories and workshops where work to temporarily raise the indoor temperature is frequently performed, and where false alarms are commonplace.

[Brief explanation of drawings]

FIG. 1 is a general block diagram of an automatic fire alarm system showing an example of the device of the present invention, and FIG. 2 is a flowchart showing its operation. 1...Fire detector, 2...Receiver, 10...Circuit breaking circuit, 30...Preliminary alarm circuit, 40...Start-up and recovery circuit, 60...Time advance alarm circuit, 70
...Break-off time timer circuit, 80...Break-off time display circuit.

Claims (1)

[Claims] 1. A cutoff circuit is provided in the fire alarm circuit that connects the fire detector and its receiver, and when the cutoff circuit is activated, the fire alarm circuit is cut off and the fire signal from the fire detector and the fire detector is interrupted. In addition to connecting with a preliminary alarm circuit that detects and issues a preliminary alarm,
An automatic fire alarm device characterized in that the cut-off circuit is configured such that the operation of the circuit stops after a predetermined cut-off time has elapsed, and the circuit automatically returns to the fire alarm circuit.