JPS5949694A - Gas leak/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 gas leak and fire detection device that is capable of detecting heat-generating scum such as city gas, and also detecting temperature, thereby also detecting the occurrence of a fire.

In recent years, as disaster prevention awareness has improved, there has been a demand for the installation of disaster prevention detection devices such as scum leak detectors and fire detectors even in general households. However, each of these disaster prevention detection devices is quite expensive, and installing multiple types of these devices is a considerable burden on ordinary households. ``It was a hindrance.

Therefore, the gas leakage and fire detection device according to the present invention makes it possible to detect fires without installing a separate fire detector by simply adding a slight configuration to the gas leakage detectors that have been manufactured in large numbers in the past. It is something.

Conventionally, 5n (J2. Zn
There are those that do not use an O"9 oxide semiconductor as a gas output element, or those that use a platinum wire using a catalytic combustion method as a waste detection element, but in any case, the detection part does not detect gas. Gas detection is performed by forming a shift bridge circuit on one side of the detection element and compensating for changes due to factors other than gas detection.

The gas leak and fire detection device according to the present invention focuses on the compensation portion of the bridge circuit, and achieves the above object by disrupting the equilibrium state as necessary.

That is, some thermistors have a resistance value that rapidly changes at a specific temperature due to phase transformation.

For example, as shown in Figure 1a, as the temperature of barium titanate increases, its resistance value increases rapidly at a specific temperature of 1. When the temperature of vanadium is increased, its resistance value rapidly decreases at a specific temperature T2. Here, these devices whose resistance value changes rapidly are collectively referred to as critical temperature characteristic thermistors.

Therefore, as shown in Fig. 2, a critical temperature characteristic thermistor 1'S2 whose resistance value rapidly decreases at a specific temperature 1'2 as shown in Fig. 1 1] above is used in the bridge circuit [3]. It is connected to the side facing the gas detection element GS, and its output signal is detected by the comparison circuit CP. In this case, the specific temperature T2 is a temperature suitable for fire detection, for example 6
Set the temperature to 5℃. With such a configuration, at normal temperature, the impedance of the gas detection element O8 decreases as the detected gas concentration increases.
By monitoring the output signal of bridge circuit B, debris can be detected. In addition, when a fire occurs and the temperature rises and exceeds the set temperature, the critical temperature characteristic thermistor T S2 rapidly decreases its resistance value, and relatively, the gas detection element G8 decreases its impedance. Similarly, bridge circuit B generates an output signal. By monitoring the output signal of the bridge circuit I3 in this manner, a gas leak or a fire can be detected.

Further, as shown in FIG. 3, a critical temperature characteristic thermistor 1'S1 whose resistance value increases rapidly at a specific temperature T1 as shown in FIG. 1a above is connected to a bridge circuit B.
The waste detection element G is connected to the side adjacent to 8, and its output signal is detected by the comparison circuit CP. In this case as well, the specific temperature 1'1 is set to a temperature suitable for fire detection. With such a configuration, gas is detected at normal temperature as in the embodiment shown in FIG.
181 suddenly increases its resistance value, which is relatively similar to the case where the impedance is decreased by the dregs detection element GS, and the bridge circuit B generates an output signal.

As described above, the gas leak detection device according to the present invention is equipped with a bridge circuit of a gas leak detector, which has been manufactured in large numbers in the past. This makes it possible to detect fire simply by adding a thermistor, making it extremely useful for the widespread use of disaster prevention detection devices.

[Brief explanation of the drawing]

Figures 1a and b are curve diagrams showing the temperature characteristics of the thermistor used in this invention, Figure 2 is a circuit diagram of one embodiment of the gas leak and fire detection device according to the invention, and Figure 3 is another embodiment. FIG. B...bridge circuit, GS...gas detection element. TS...Critical temperature characteristic thermistor. Patent applicant: Nittan Electric Co., Ltd.

Claims (1)

[Claims] A critical temperature characteristic thermistor whose resistance value changes rapidly at a specific temperature is connected to at least one other side of a bridge circuit whose one side is a waste detection element, and a detection signal is obtained from the output signal of the bridge circuit. Gas leak and fire detection device.