JPS5972597A - Fire sensor - 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 fire detector that emits different signals to a receiver depending on changes in the ambient temperature of an electric circuit within the detector.

As the systemization of disaster prevention equipment progresses, fire detectors are also becoming more and more popular, such as those that send information such as the amount of smoke to the receiver in analog form, or those that send address signals indicating the location of those detectors to the receiver. has been requested. In this case, various electronic components such as ICs are used in the detector, but if these components are exposed to heat exceeding their rated and storage temperatures as the fire spreads, their functionality will rapidly deteriorate. The degraded A could no longer be used again, and had drawbacks such as the inability to accurately transmit the fire status to the receiver.

In consideration of the above points, this invention protects the electric circuits in a fire detector with a heat insulating material, prolongs the time it takes for these circuits to detect a fire, and furthermore, when the ambient temperature of these circuits exceeds the rated temperature of the circuit elements, It is an object of the present invention to provide a fire detector that detects a fire using fire detection means that is more reliable than detection using these circuits, and that notifies a receiver of these conditions using different signals.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings, taking a thermal sensor as an example. Outside Figure 1 and in Figure M2, ] is a thermistor as a heat-sensitive element, 2 is a heat receiving plate, 3 is a bowl-shaped pace, 4 is a heat insulating material provided to cover the inner wall of the base 3, 5 is a printed board, 6 is an electric circuit in the fire detector made up of IC etc. and covered with the heat insulating material 4, 7 is a bimetal that operates at the rated temperature of the circuit element and closes the contact, 8 is the maximum rating of the circuit element The temperature fuse melts at the storage temperature, which is the storage temperature, and the temperature fuse melts at the maximum operating temperature of the 9-key bimetal 7. As shown in FIG. 2, the electric circuit 6 includes a sensor circuit A consisting of a series circuit of the thermistor 1 and a resistor, and an amplifier thereof, a constant voltage circuit that maintains the pressure at a certain level, and the A-D converter. The bimetal 7 is connected to a terminal via a resistor R connected in parallel with the temperature fuse 9.

Connection can be written between 0.

Next, the operation of the above-mentioned sensor will be explained with reference to the characteristic curve diagram of FIG. 3, which shows how the terminal voltage of the sensor changes depending on the change in the ambient temperature of the electric circuit inside the fire sensor.

Even if a fire occurs and the ambient temperature outside the detector rises, the action of the heat insulating material 4 causes the ambient temperature of the electrical circuit 6 inside the fire detector to rise to point P, which is the rated temperature of the element, as shown by curve a. While the temperature is maintained below b, the thermistor l directly receives the heat from the fire on the heat receiving plate 2, and its analog quantity is output from the sensor circuit A, which is converted from A to D by the A to D converter circuit B, and then the transistor T is A digital pulse as shown by curve b1 is superimposed on the voltage between the terminals and sent to the receiver. If the fire progresses and the ambient temperature of the electric circuit inside the detector exceeds the rated temperature of the circuit element, the bimetal 7 will operate and the contact will close, as shown by curve b2, and the voltage between C will become almost zero. The spread of the fire is then transmitted to the receiver, and the power supply to the circuit elements is stopped to prevent destruction of the elements. Also, as shown by curve a, once the ambient temperature drops, sensor circuit A is activated again, and the temperature change in the sensing area is transmitted to the receiver as a digital pulse, as shown by curve b/2. As the fire spreads further, the bimetal 7 operates to ensure that the ambient temperature of the electric circuit 6 in the fire detector exceeds the rated temperature, and when it reaches the storage temperature point Q, which is the maximum rated temperature, the temperature fuse 8 melts. It is recorded that the circuit element has reached storage temperature. Further, when the ambient temperature of the circuit 6 reaches point X, which is the maximum operating temperature of the bimetal 7, as shown by curve a, the temperature fuse 9 melts and the resistance R
is connected between the terminals and 5 through the bimetal 7, and generates a terminal voltage as shown by curve b3, and this state is transmitted to the receiver.

Furthermore, by measuring the current consumption flowing through the sensor after the fire is extinguished, it is possible to determine whether or not the fuse 8 has melted. It is possible to determine whether the person has been exposed to

Further, in the above embodiment, a part of a sensor of a thermal sensor is used as the sensor circuit A, but a part of a sensor of a known ionization type or scattered light type smoke detector may be used as the sensor circuit.

Since this invention is configured and operates as described above, it is possible to detect fire with a highly reliable fire detection means according to the ambient temperature of the electric circuit in the fire detector, and whether it is reusable or not. This has the effect of providing a fire detector that can be easily inspected.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a fire detector according to an embodiment of the present invention, FIG. 2 is a circuit diagram of the sensor shown in FIG. 1, and FIG. 3 is a characteristic curve diagram of the sensor shown in FIG. 1. DESCRIPTION OF SYMBOLS 1...Thermistor, 2...Heat receiving plate, 3...Heath, 4...Insulating material, 5...Printed board, 6...Electric circuit in sensor, 7...Bimetal, 8.9... Temperature fuse, A... Sensor circuit, B... A-D conversion circuit, D... Constant voltage circuit, r, R... Resistance. Patent application Jinnomi Disaster Prevention Industry Co., Ltd. Figure 1 Voltage between L Figure 2 (V) Figure 3 Time

Claims (1)

[Claims] 1. The electrical circuit of the fire detector is protected by a material with a large thermal time constant, and depending on the ambient temperature of this electrical circuit, it is switched to a highly reliable fire detection means, and these outputs send different signals to the receiver. A fire detector characterized by a fire alarm.