JPH01143926A - Abnormal overheat detecting method - Google Patents

Abstract

PURPOSE:To stably and accurately detect abnormal heating at a conductor contact part and other parts where the heating possibly occurs from the production of a gas by charging a gas producing agent in a cylinder container equipped with a plug of low-meeting point alloy which has its meeting point at overheating detection temperature point. CONSTITUTION:The gas producing agent 7 which produces the gas when said agent is heated at temperature below the overheating detection temperature is charged in the cylinder container 5 equipped with the plug 6 made of the low-meeting point alloy having its meeting point at the overheating detection temperature, and circuit conductors 1 and 2 which are connected mutually are installed at an object position of abnormal overheating detection, e.g. in an enclosed switchboard 4. Then the gas producing agent 7 is heated with the heat of abnormal overheating at the object position of detection to produce the gas and when the detection object position reaches the overheating detection temperature, the plug 6 melts to open the cylinder container 5. Consequently, the gas is discharged from the cylinder container 5 and detected by a gas detector 8 to detect the abnormal overheating of the circuit conductors 1 and 2 as the detection object position.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for detecting abnormal overheating due to, for example, poor contact at a circuit conductor connection portion.

(Prior technology) To detect abnormal heating due to poor contact at circuit conductor connection parts, an insulating material that melts when the temperature rises is applied to the conductor connection part, and the insulating material that melts and falls vertically below is applied. The receiver was equipped with a plate, and the receiver was designed to detect abnormal overheating of the conductor by determining the amount of insulating material that had accumulated in the plate.

However, it is necessary to prepare a tray for each circuit conductor connection part to be detected, and the tray must also be equipped with a mechanism to determine the amount of insulating material received by the tray. The whole process is extremely complicated, large-sized, and expensive.

(Problems to be Solved by the Invention) This invention detects abnormal overheating at conductor connections and other places where heat may be generated by the generation of gas, and can respond stably and accurately to the temperature to be detected. The purpose is to do so.

(Means for Solving the Problems) This invention includes a plug made of a low melting point alloy whose melting point is the overheating detection temperature at the location where abnormal overheating is to be detected, and the inside of which is heated at a temperature lower than the overheating detection temperature. A cylinder container filled with a gas generating agent that generates a gas when When the temperature rises to a detection temperature, the stopper melts and opens the cylinder container, thereby releasing the gas from the cylinder container to the outside, and detecting the released gas by a gas detector. It is characterized by detecting abnormal overheating at the detection target location.

(Function) When abnormal overheating occurs at the location where abnormal overheating is to be detected, gas is first generated from the gas generating agent due to the heat. This gas gradually reduces the internal pressure of the cylinder. The abnormal superheating temperature further increases and the low melting point alloy melts F! When temperature A is reached, the stopper of the cylinder container melts and opens, allowing the gas that has been generated up to that point to be released to the outside. By detecting this gas with a gas detector, it becomes possible to detect the occurrence of abnormal overheating at the detection target location.

As for the low melting point alloy used as the stopper, if you select and use one whose melting point is at the detection target temperature, for example, about 100 to 200°C, when the temperature rises to the detection target temperature,
It melts accurately and opens the cylinder container.

As this type of low melting point alloy, for example, eutectic solder, Homberg alloy, etc. can be used. Eutectic solder is Sn
61.9%, Pb 3g, 1%, and the melting point is 183°C. In addition, Homberg alloy is B134%
, Pb 33%, Sn 33%, and the melting point is 125°C.

As the gas generating agent, one that generates CO□ gas is suitable. Specifically, carbonate may be used alone or in combination with an organic acid. For example, a mixture of calcium carbonate and maleic acid (melting point 130°C) in a ratio of 1 = 2, an organic acid wrapped in a diaphragm with a low melting point and placed in a carbonate such as calcium carbonate, and even One that uses sodium bicarbonate alone can be used.

(Example) An example of the present invention will be described with reference to the drawings. In FIG. 1, reference numerals 1 and 2 indicate points to be detected for abnormal overheating, such as conductors connected to each other, which are connected by tightening bolts 3 or the like. 4 is a closed switchboard equipped with this circuit conductor.

5 is a cylinder container, which is sealed with a stopper 6 made of a low melting point metal. The cylinder container 5 is fixed to the surface of the detection point, that is, the surface of the conductor 1, with adhesive or a suitable band having sufficient fixing ability.

The inside of the cylinder container 5 is filled with a gas generating agent 7. A gas detector 8 detects gas released from the cylinder container 5, and is installed in the same closed switchboard 4 together with the conductors 1 and 2.

In the example shown in Figure 1, if a mixture of calcium carbonate and maleic acid is used as the gas generating agent 7, and eutectic solder is used as the plug 6, overheating will occur at the connection point of the conductors 1 and 2. When it occurs and the temperature rises, first 13
At 0°C, maleic acid begins to dissolve and reacts with calcium carbonate to generate CO2 gas.

As the temperature further rises, the amount of CO□ gas generated increases and the internal pressure of the cylinder container 5 increases. When the temperature reaches 183° C. or higher, the stopper 6 melts and the internal pressure of the cylinder container 5 releases CO□ gas to the outside. When the gas detector 8 detects this, the occurrence of abnormal overheating is detected.

Note that as the gas detector 8, for example, an infrared detector, a glass electrode diaphragm type detector, etc. can be used.

In any case, it is sufficient to detect that the concentration of CO2 gas has increased beyond a predetermined value, and to sound an alarm or to put the output on-line.

The example shown in Figure 2 is polyethylene (melting point 108°C)
This is an example in which glutaric acid 10 is wrapped in a diaphragm 9 made of the following, placed in calcium carbonate 11, and sealed in a cylinder container 5. Here, Homberg alloy was used as the stopper 6.

In this case, the conductor gets heated up due to overheating.

Glutaric acid 10 melts at 98° C. or higher, and then diaphragm 9 melts at 108° C. or higher, and glutaric acid 10 flows out from the diaphragm 9 and reacts with calcium carbonate 11 to generate CO□ gas. If it is further heated to 125℃ or higher, stopper 6
is melted and CO□ gas is released to the outside. Gas detector 8 detects this.

The above was an example of generating 003 gas with carbonate and organic acid, but instead of generating CO2 gas by heating alone.
It may also be one that generates a gas, for example, only sodium bicarbonate may be used.

Now connect this to the plug 6 made of eutectic solder as shown in Figure 1.
If we confine the sodium bicarbonate in the atmosphere and heat it by overheating a conductor, the sodium bicarbonate will first be thermally decomposed at temperatures above 100°C and generate CO2 gas. This increases the internal pressure of the cylinder container 5, but once the dissociation pressure at that temperature is reached, no further decomposition occurs (third
See diagram. ).

As the temperature rises, the internal pressure of the cylinder container 5 increases and when it reaches 183° C. or higher, the stopper 6 melts and releases CO2 gas. At this time, unreacted sodium bicarbonate is also thermally decomposed and CO□ gas is completely released.

(Effects of the Invention) As detailed above, according to the present invention, the occurrence of abnormal overheating is detected by gas detection, so instead of receiving the insulating material that melts at each detection target point as in the past, it is replaced by a plate. Since the gas generating agent is sealed and filled in the cylinder container, stable characteristics can be maintained over a long period of time, and the stopper of the cylinder container is made of a low melting point alloy. With this structure, the overheating detection temperature can be set in a convenient manner, and therefore abnormal overheating can be accurately detected.

[Brief explanation of the drawing]

Fig. 1 is a sectional view for explaining an embodiment of the method of the present invention, Fig. 2 is a partial sectional view for explaining another embodiment of the method of the invention, and Fig. 3 is a dissociation pressure characteristic of sodium bicarbonate. It is a diagram. 1.2... Conductor, 5... Cylinder container, 6... Stopper,
7...Gas generating agent, 8...Gas detector, 7...ErL is LjiC)

Claims (1)

[Claims] A stopper made of a low melting point alloy whose melting point is the overheating detection temperature is provided at the location where abnormal overheating is to be detected, and the inside is filled with a gas generating agent that generates gas when heated to a temperature lower than the overheating detection temperature. A cylinder container is installed, and the gas generating agent is heated by the heat due to abnormal overheating of the detection target location to generate gas, and when the detection target location further rises to the overheating detection temperature, the stopper melts. Abnormal overheating at the detection target location is detected by opening the cylinder container, thereby releasing the gas from the cylinder container to the outside, and detecting the released gas with a gas detector. An abnormal overheating detection method characterized by: