JPS5886695A - Fire detector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mud fire detection device that is capable of detecting the location of a fire and is also less susceptible to noise.

The conventional fire detection device has a fire detection line (as shown in Figure 1).
It consists of a receiver (2) and a receiver (2).

For fire detection wires, two core wires (5) with conductor (3) coated with low-melting point plastic (4) are twisted together, a pressure tape (6) is applied to the outer periphery, and a sheath (
7) is used, and the receiver (2) includes a transformer Tr, a relay Ry display lamp PL, and an alarm buzzer BZ.
The one that consists of is used.

And this device uses low melting point plastic (
4) melts due to the heat of the fire and a short circuit occurs between the conductors (3), current flows through the relay Ry to the indicator light PL and the buzzer BZ, which operate to detect the occurrence of a fire. .

Although this device can detect the occurrence of a fire, it cannot detect the location of the fire, which makes it difficult to extinguish the fire quickly.

Furthermore, if the fire detection line is installed near a power cable, control cable, etc., it has the disadvantage that it is susceptible to noise, and if the noise is large, the receiver itself may malfunction.

An object of the present invention is to provide a fire detection device free from such difficulties, and one embodiment of the present invention is designed to detect a fire as shown in FIG. It consists of a line (8) and a receiver (9). Fire detection line (8)
As shown in Fig. 4, a conductor such as hard steel wire or piano wire (101 is covered with an insulating material 01 made of low melting point plastic or other low melting point material) to form a core wire (I21), and this core wire is Twist the two wires together and wrap copper tape, aluminum tape, aluminum mylar tape, etc. around the outer circumference or attach them vertically to form a shielding layer (131'f), and then cover the entire surface with a plastic sheath, pressure tape, etc. The thing I put on it is kumquat.

The receiver (9) includes a display lamp, a buzzer, etc. (not shown), a variable resistor f15+, a differential amplifier (+6
1. A drive body 07) using a DC servo motor is used.

In the present invention, as shown in FIG. 3, one of the two core wires (121) of the fire detection wire (8) is
8) is connected to the terminal ell of the shield (13), and the other end (201) of this core wire (12) is connected to the variable resistor (201) of the receiver (9).
By connecting one end (2I) of 19 to the other end (221) of the shield 03 to the other end (23) of the variable resistor (151), the core wire 02 and the variable resistor (15) can be connected. A Wheatstone bridge circuit is formed as shown in Fig. 5, and one end C94)' of the other core wire O2 is connected to the balanced detection terminal (2■) of the bridge circuit via a differential amplifier α6). It is what it is.

To use the fire detection location of the present invention, the fire detection wire (8
) It suffices to install it at fire detection locations such as the floors and walls of all buildings, and near cables, and it will serve as the input voltage of the dynamic amplifier (16). The difference between this voltage and the voltage at the moving terminal (25) of the variable resistor (I5) is applied to the differential amplifier (16).
The signal is amplified and input to the driver (171), and this input causes the driver On to operate and move the moving terminal (25) 'fr to the equilibrium point.

At this time, the movable resistor (both ends of I51 (2+1(23+
Total voltage between and moving terminal (29) & , Et total, total length of fire detection wire (8) t' t % Length fx of the same detection wire (8) from short-circuit point 0 to receiver (9), short-circuit Assuming that the length from point 0 to the terminal of the fire detection line is f t -x, X is determined as follows.

x: (t-x) =E, :Et...
(1) x&= (t-x) E, @・e・・(
21x (&10&)=tEx ” ” '
...(:31 From formula (5), in order to find the length xk from the receiver (9) to the point of fire outbreak 0, it is sufficient to find the voltage E. (E is the power supply voltage, t is the total length of the fire detection wire, which is already known.) The driving body 0η may be a pulse motor instead of a DC servo motor, and in this case, an A/D converter is connected to the output of the differential amplifier (16). The output voltage can be converted into digital data, inputted into a microcomputer, and then an instruction can be given to the pulse motor to set all A/D conversion contents (bits) to 0.

The voltage E may be measured by any suitable means commonly used. The measured voltage Et may be input into the microcomputer of the receiver (9), and the length xk to the fire occurrence position may be automatically determined using the above equation (5), and this may be displayed digitally. In this case, the shielding layer α3) is grounded at one point to make it less susceptible to external noise.

In this case, if the shield is grounded at two or more points, an induced voltage will be generated in the shielding layer 0'3 when a current flows to the ground, which will adversely affect the detection of fire occurrence, so the grounding must be made at the l1 point.

Also, make sure that the internal wiring of the receiver (9) is isolated from the fire detection # (81) and insulated from the earth.If the DC power source E is a dry battery, there will be no problem, but if the AC power source is a transformer, When obtaining DC power through a rectifier, if the secondary side of the transformer is not insulated from the ground on the AC power supply side, the ground point on the power supply side and the shielding layer (13) of the fire detection wire (8)
) will form a loop with the ground point of the AC power source, making it more susceptible to induction. Therefore, when obtaining DC power from an AC power source, use an isolation transformer to use a DC power source that is isolated from the ground on the AC power source side. As described above, the present invention is characterized in that one of the two core wires 02) of the fire detection wire (8), the shielding layer (13), and the variable resistance in the receiver (9) are used. form a bridge circuit with the conductor (15), and connect the other conductor (12)'t.
The balance detection end of the Zub9f circuit (because it is connected to 29,
When the twisted core wires (12) are short-circuited due to a fire, the bridge circuit is balanced and the voltage E1 at that time is measured to reliably detect the location of the fire (point 0).

Furthermore, if the bridge circuit is automatically balanced as described in claim 2, the entire location of a fire can be quickly detected. 5) By performing arithmetic processing based on the formula, when the core wires 02 are short-circuited due to a fire, the location of the fire occurrence will be immediately digitally displayed, making it possible to detect the location of the fire even more quickly, and, in turn, expediting extinguishing operations. Also useful.

Furthermore, as described in claim 3, the fire detection line and the internal wiring of the receiver connected thereto are grounded at one point through the shielding layer 0, making them less susceptible to external noise. Therefore, highly accurate fire detection can be performed.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing an example of a conventional fire detection device;
The figure is an explanatory diagram of the fire detection wire used in the device, FIG. 3 is an explanatory diagram showing an example of the fire detection device according to the present invention, FIG. 4 is an explanatory diagram of the fire detection wire used in the device, and FIG. 5 is an equivalent circuit diagram of FIG. 4. FIG. (8) is the fire detection wire, (9) is the receiver, 001 is the conductor, (11) is the insulator, θ2 is the core wire, (131 is the shield, (19 is the variable resistor, 0η is the driver. Figure 2 Figure 4

Claims (1)

[Scope of Claims] (1) Consisting of a fire detection wire and a receiver, which are made by twisting two core wires in which a conductor is coated with a low-melting point insulating material, and providing a metal electromagnetic shielding layer on the outside of the core wires. , the fire detection wire connects the terminal of the shielding layer and the terminal of one of the two core wires,
By connecting the sleeve end of this core wire to one end of the variable resistor in the receiver and the other end of the shield to the other end of the same resistor, a bridge circuit is formed between this core wire and the variable resistor in the receiver. (2) The balance detection end of the bridge circuit is connected to the balance detection end of the bridge circuit by a driver when the core wires are short-circuited. The fire detection device according to claim 1, wherein the fire detection device is automatically moved until the fire is removed. (3) The fire detection device according to claim 1, wherein the fire detection line and the internal wiring of the receiver connected thereto are grounded at one point via a shielding layer.