JPS5937911Y2 - fire alarm repeater - Google Patents

Description

[Detailed explanation of the idea] This invention relates to the improvement of fire alarms.

Figure 1 is a circuit diagram of a conventional fire alarm system, where 1 is the receiver, 2
is a line having a power source for the receiver 1; 3 is a repeater connected in parallel to the line 2 and provided in each caution area; and D is a fire alarm provided in the repeater 3.

When a detector is activated due to a fire outbreak, the relay N of the associated relay 3 is activated, its contact n is closed, and the relay N is self-maintained, and the relay N is connected to the relay 3 through other contacts (not shown). A signal was sent to Receiver 1 to display the fire area.

However, since there is no particular restriction on the current flowing through the line 2 when the repeater 3 operates, if each repeater operates one after another, a predetermined voltage may not be obtained at each repeater 3 due to the voltage drop on the line 2. There is a fear that the repeater 3 will be lost, which has the disadvantage that the number of repeaters 3 that can be connected is limited.

In view of the above points, the present invention provides a fire alarm system that allows a large number of repeaters to be connected in parallel to a line by limiting the current flowing through the line when the repeaters are in operation.

Hereinafter, the fire alarm system of the present invention will be explained with reference to the drawings. In the embodiment shown in FIG. 2, 3 is a repeater installed in each warning area connected in parallel to the railway line, and 4.5 is a connection terminal of the repeater 3. , Dl is a fire detector equipped with a self-holding circuit such as an ion type or photoelectric type, and D2 is a fire detector without a self-holding circuit that mechanically detects heat, such as a bimetal or differential type. are connected in parallel to connection terminals 6 and 7 of.

N is a detection relay connected in series to the detectors DI and D2, C is a constant current circuit that limits the current when the relay N is in operation, and S is a fire detector DI.

A switching circuit that becomes non-conductive when D2 is activated and conductive when restored, is connected in series with the make contact n of the relay N to form a self-holding circuit for the relay N.

The constant current circuit C includes a transistor T1 having a relay N connected to its emitter side, and a Zener diode d1 connected in parallel with the relay N through the base and emitter of the transistor T1. A first constant current consisting of a constant current circuit, a transistor T2 connected between the base and collector of the transistor T1 through a resistor R1, a diode d' connected in parallel to the resistor R1 through its base and emitter, and its bias resistor R2; and a second constant current circuit that limits the control current of the circuit.

Further, the switching circuit S is connected to the sensor D19 due to the voltage drop across the resistor R3 connected in series with the sensor D2.
A transistor T3 is turned ON by detecting the operation of D2, and a resistor R6 is connected to the emitter side, which is turned OFF when R5 of bias resistor R4 and R5 is short-circuited by the transistor T3.
A transistor T4 is provided.

Next, to explain the operation of the embodiment shown in FIG. 2, the fire detector D1, which is equipped with a self-holding circuit such as an ion type
When activated, a constant current flows through the relay N due to the action of the constant current circuit C, and the relay N is activated, and a signal unique to the relay 3 is sent to the receiver through contacts not shown, and the fire area is displayed. .

Furthermore, while the sensor D1 is operating, the switching circuit S maintains a non-conducting state, so that the constant current circuit C is not burdened with unnecessary current that would be generated when a self-holding circuit of the relay N is configured. By doing so, care is taken to prevent the current consumption of the repeater and the entire system from increasing.

Further, if the sensor D1 is provided with an operation indicator light, the indicator light is lit with a constant current by the action of the constant current circuit C.

Furthermore, even if the fire detector D2, which is not equipped with a self-holding circuit such as a bimetal type, operates, the constant current circuit C
Since the resistors R1 and R2 are selected to have high resistance, a constant current approximately determined by the constant current circuit C flows through the repeater 3.

When the sensor D2, which is not equipped with a self-holding circuit, is restored, the transistor T3 changes from ON to OFF, and the transistor T4 conducts to the closed make contact n.
A weak self-holding current flows through the relay N to maintain its operation.

In the embodiment of FIG. 3, the transistor T 5 p T is complementary connected to the connection terminal 4°5 of the repeater 3.
6, a Zener diode d2, and a high-resistance resistor R7 through which its bias current flows, a constant voltage circuit is connected to the output side of the constant voltage circuit, and a relay N, a resistor R3 of a switching circuit S, and a fire detector D1. A series circuit of D2 is connected, and a Zener diode d3 is connected in parallel to the relay N through the base-emitter of the transistor T6, so that the fire detector D1. A circuit C is configured which functions as a constant voltage circuit when D2 is not in operation and as a constant current circuit when it is in operation.

The rest is the same as the embodiment shown in FIG. 2 above.

Next, to explain the operation of the embodiment shown in FIG.
1. When sensor D2 is inactive, the constant voltage circuit operates to activate the sensor D1.D2. The voltage across D2 is held constant and the voltage across sensor D1. When D2 is in operation, the constant voltage circuit acts as a constant current circuit due to the action of the Zener diode d3, so that the same effect as in the embodiment shown in FIG. 2 can be obtained.

According to the present invention, as described above, since the current flowing through the line when the repeater is operating is limited to a small amount, it is possible to obtain a fire alarm system in which a large number of repeaters can be connected in parallel to the line.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram of a conventional fire alarm, Figures 2 and 3 are
The figures are circuit diagrams of different embodiments of a repeater used in a fire alarm according to the present invention. D 1 j D 2... Fire detector, N...
...Relay, n...Make contact, c, c
'-... Constant current circuit, S... Switching circuit.

Claims (1)

[Scope of utility model registration request] 1. A fire detector equipped with a self-holding circuit such as an ion type or photoelectric type and a fire detector without a self-holding circuit such as a bimetallic or differential type are connected in parallel, and the operation of these fire detectors is carried out on a common electric circuit. In a fire alarm that is transmitted to a receiver through a repeater to which a plurality of repeaters are connected in parallel, the repeater includes a relay that detects the operation of the fire detector, and a relay that detects the operation of the fire detector. and a self-holding circuit for the relay, which is comprised of a constant current circuit that limits the current of the relay, and a series circuit of the make contact of the relay and a switching circuit that conducts when the fire detector is restored. fire alarm. 2. The constant current circuit is composed of a first and a second constant current circuit,
The first constant current circuit limits the current flowing through the relay, and the second constant current circuit limits the control current flowing through the first constant current circuit.Claim 1 of the Utility Model Registration Claim: Fire alarm listed.