JP3058716B2 - Temperature sensitive element destruction test equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a destructive test apparatus for performing a test until a temperature-sensitive element having a self-temperature control characteristic, for example, a temperature-sensitive element such as a sheet heating element is broken.

[0002]

2. Description of the Related Art Japanese Patent Application No. Sho 63-309825 filed by the present applicant and Japanese Patent Application No. Hei 1-270939 filed by the present applicant are examples of temperature-sensitive elements having the above-mentioned self-temperature control characteristics.
There is a number. The former application is a composite of graphite or carbon black and a low-dimensional substance mainly composed of a cross-linked polymer and a linear polymer, and the latter application is a cross-linked polymer formed of graphite or carbon black. And a composite of a low-dimensional substance mainly composed of a linear polymer and an inorganic compound.

[0003] By the way, the temperature-sensitive element having the above-mentioned structure is used as a sheet heating element. However, in this temperature-sensitive element, the characteristics of the temperature-sensitive element deteriorate or deteriorate in the manufacturing process, in actual use, or when left naturally. It shows. Therefore, before commercialization using the above-described device, the characteristics of the device and the change in characteristics shown during actual use and, if actually used, what process leads to destruction, It is necessary to measure in advance.

Therefore, conventionally, direct current or alternating current overvoltage is applied to the surface heating element, and measurement is performed by destruction of the surface heating element due to a rise in temperature.

[0005]

However, in the above-mentioned life test, it is impossible to find an accurate destruction process because it is performed by destruction due to a temperature rise of the temperature-sensitive element. There was a problem.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to make it possible to find a process leading to the destruction of a temperature-sensitive element by using a simple device, and to use a temperature-sensitive element. It is an object of the present invention to provide a temperature-sensitive element destruction test device capable of continuously measuring a change in internal resistance of the device.

[0007]

SUMMARY OF THE INVENTION A destructive testing apparatus for a thermosensitive element according to the present invention is intended to achieve the above-mentioned object.
The means includes a pulse generator that outputs a high-frequency pulse, a means that generates a high-voltage pulse output by a pulse from the pulse generator, and a temperature-sensitive element to which the high-frequency and high-voltage pulse is applied. A temperature sensor for detecting a temperature of the temperature-sensitive element; and an analog recorder for displaying an internal temperature of the temperature-sensitive element based on an output from the temperature sensor.

A DC power supply is connected to the circuit through a series circuit of a choke coil and a resistor for cutting a pulse to the temperature sensing element, and a resistor is connected in series with the temperature sensing element. Then, a circuit for measuring the voltage generated in the two resistors and continuously measuring the change in the resistance value of the temperature sensing element is connected.

[0009]

According to the thermosensitive element destruction test apparatus of the present invention having the above-described structure, when a high-frequency, high-voltage pulse is applied,
The surface temperature of the temperature sensing element is detected by a temperature sensor and recorded on an analog recorder. Then, in the recorded waveform diagram, when the crystal of the temperature-sensitive element is destroyed, the internal temperature of the temperature-sensitive element greatly fluctuates, so that the destruction state of the temperature-sensitive element can be known.

In addition, a DC power supply is connected to the temperature-sensitive element via a series circuit of a choke coil and a resistor for cutting a pulse, and a resistor is connected in series with the temperature-sensitive element to form the two resistors. Since the circuit for measuring the voltage generated in the temperature sensor is connected, it is possible to continuously measure the change in the resistance value of the temperature-sensitive element.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A temperature-sensitive element such as a surface heating element is made of a conductive material of carbon and mixed with another insulating material. In general, a type of capacitor having a dielectric between two electrodes and a resistive element are mixed. It can be regarded as a circuit. Here, the point different from a normal capacitor is that the resistance characteristic is much higher than the capacitor characteristic and the resistance characteristic, and that the capacitor characteristic has a strong influence on the resistance characteristic even in direct current. .

As described above, the characteristics of this element are such that a current flows with a kind of resistance against a direct current, and is not a dielectric property of a normal capacitor but a low value for an alternating current. The current flows through the resistance characteristic damped by the value. For this reason, the destructive test according to the present invention was performed using the following test apparatus.

In FIG. 1, 1 is a pulse generator,
It generates a pulse voltage of a constant frequency (for example, 3200 Hz). Reference numeral 2 denotes a transistor which is turned on by a positive pulse from the pulse generator 1, reference numeral 3 denotes a power transistor which is turned on when the transistor 2 is turned on, and reference numeral 4 denotes one end of a primary side 4a connected to the collector of the power transistor 3. A transformer 5 is a DC stabilized power supply connected to the emitter of the power transistor 3 and the other end of the primary side of the transformer 4, 6 is a spike killer capacitor connected to both ends of the primary side of the transformer 4, and 7 is a transformer 4 Is a surface heating element which is a temperature-sensitive element having the above-described composition and connected to the secondary side 4b.

Next, the operation will be described based on the circuit configuration. When the pulse generator 1 operates and a positive pulse is output, the transistors 2 and 3 are turned on. When the transistor 3 is turned on, a DC current from the DC stabilized power supply 5 flows to the primary side 4a of the transformer 4,
A voltage of 12000V is generated on the secondary side 4b of the surface heating element 7, and this voltage is applied to the surface heating element 7. When the output from the pulse generator 1 becomes negative, the transistors 2 and 3 are turned off, and the application of the voltage to the surface heating element 7 is cut off. Therefore, a voltage of 12000 V at 3200 Hz is applied to the surface heating element 7.

FIG. 2 illustrates a circuit for measuring the internal resistance of the surface heating element 7 to which the above-described voltage is applied. 8 is a high-voltage output unit shown in FIG. 1 for applying a high voltage to the surface heating element 7; 9 is a temperature sensor such as a thermocouple mounted on the surface of the surface heating element 7;
A converter for converting a high-frequency pulse voltage applied to the DC voltage into a DC voltage, a digital thermometer 11 for digitally displaying an output from the temperature sensor 9, a current / temperature analog recorder 12, and an output from the converter 10 And the output from the recorder are input.

When a high-frequency, high-voltage pulse is applied by the circuit 8 shown in FIG. 1, the surface temperature of the surface heating element 7 is detected by the temperature sensor 9 and displayed on the digital thermometer 11. At the same time, a waveform diagram such as the characteristic diagram shown in FIG. 3 is recorded on the analog recorder 12 to which the output from the digital thermometer 11 and the output from the converter 10 for converting a high-frequency pulse voltage into a DC voltage are input. Is done. That is, the vertical axis indicates the internal temperature of the surface heating element 7 and the horizontal axis indicates time.

Judgment from this experimental result is that in the initial state where a high-frequency, high-voltage pulse is applied, an initial fluctuation A occurs until the internal resistance becomes stable, and after a predetermined time, the first stable fluctuation A occurs. B occurs. Further, after the intermediate fluctuation C occurs about twice with the lapse of time, crystal breakage of the surface heating element 7 occurs like the first order D and the second order E. Further, a final destruction F occurs approximately 72 hours after the start of energization of the surface heating element 7. In this final destruction F, the internal resistance of the surface heating element 4 fluctuates greatly as can be seen from FIG.

As described above, by applying a high-frequency, high-voltage pulse voltage to the surface heating element 7, the process of breaking down the internal crystal in the surface heating element 7 can be known in a short time. In addition, the life of the surface heating element 7 can be improved.

Although the above embodiment measures the destruction state of the surface heating element 7, it is also important to measure the progress of the destruction state. Therefore, a circuit as shown in FIG. 4 is connected to the surface heating element 7.

That is, a parallel circuit of a resistor R ₁ and a capacitor C ₁ is connected to the secondary side 4 b of the transformer 4,
Connecting a parallel circuit of a resistor R ₂ and a voltmeter E ₁ in series.
The surface heating element 7 and the resistor R ₂ and a voltmeter E choke coil CH ₁ the series circuit of the parallel circuit ₁ and the resistor R _3, the choke coil CH ₂ resistor R ₄ and the DC constant pressure source B connected in series, and a series circuit of a resistor R ₅ and a voltmeter E ₂ is connected in parallel with a DC constant pressure source B.

As described above, the high-voltage pulse generated by the transformer 4 and the DC voltage from the DC constant-voltage power source B are applied to the surface heating element 7. Further, the high-voltage pulse does not flow after the resistors R ₄ and R _{5 due to the} choke coil CH ₁ , the resistor R ₃ and the choke coil CH ₂ . Here, the resistors R _{1 to} R ₃ and R ₅ are set to low resistance values that are not related to the basic operation of the circuit. Thus, the pulse voltage generated by the current of the high-voltage pulse is generated in the voltmeter E ₁ is the resistor R _2.

On the other hand, since the as surface heating element 7 which is the DC voltage via a resistor R ₄ from the DC constant-pressure source B is applied, divided by the resistance value of the resistance value and the resistance R ₄ of the surface heating element 7 pressure voltage is generated in the voltmeter E _2. Here, the resistance R
_{Since 5} is a protection resistor, its resistance value does not need to be considered. Then, the voltage between the voltmeters E ₂ and E ₁ , that is, A
Since the voltage is substantially equal to the point and A ', by measuring the voltage of the voltmeter E ₂ continuously, it is possible to continuously measure the resistance value of the surface heating element 7.

[0023]

As described above, the present invention measures the temperature of a temperature-sensitive element by applying a high-frequency, high-voltage pulse voltage to the temperature-sensitive element such as a surface heating element. It is possible to know the process of crystal destruction, so that it is possible to improve the life of the thermosensitive element by referring to the experimental results, and to continuously measure the change in the resistance value of the thermosensitive element. Therefore, the present invention has an effect that the characteristic change of the temperature sensing element can be known.

[Brief description of the drawings]

FIG. 1 is a circuit diagram for applying a high-frequency, high-voltage pulse to a surface heating element.

FIG. 2 is a circuit diagram for recording a temperature characteristic of a temperature sensing element;

FIG. 3 is a characteristic diagram showing an internal temperature characteristic with respect to time of a temperature-sensitive element.

FIG. 4 is a circuit diagram for measuring a characteristic change of a temperature-sensitive element.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Pulse generator 4 Transformer 5 DC stabilized power supply 7 Temperature sensing element (surface heating element) 8 High voltage output part 9 Temperature sensor 12 Analog recorder CH ₁ , CH ₂ Choke coil R _{1 to} R ₅ Resistance E ₁ , E ₂ Voltage Total B DC constant voltage power supply

Claims (2)

(57) [Claims] 1. A pulse generator for outputting a high frequency pulse, means for generating a high voltage pulse output by a pulse from the pulse generator, a surface heating element to which the high frequency and high voltage pulse is applied, etc. A temperature sensor for detecting the temperature of the temperature-sensitive element, and an analog recorder for displaying an internal temperature of the temperature-sensitive element based on an output from the temperature sensor. Device destruction test equipment. 2. A pulse generator for outputting a high-frequency pulse, means for generating a high-voltage pulse output by a pulse from the pulse generator, a surface heating element to which the high-frequency and high-voltage pulse is applied, etc. Temperature sensor, a temperature sensor for detecting the temperature of the temperature sensor, an analog recorder for displaying the internal temperature of the temperature sensor by an output from the temperature sensor, and a pulse cut to the temperature sensor. A DC power supply is connected through a series circuit of a choke coil and a resistor for connecting a resistor in series with the temperature-sensitive element.
A circuit for continuously measuring the change in the resistance value of the temperature sensing element by measuring the voltage generated at the two resistors.