JPH0591653A - Overheat detector - Google Patents

Abstract

PURPOSE:To maintain high performance stably for a long period by outputting an overheating state detection signal when an output signal of a band pass filter for passing only sound of a special sound satisfies predetermined conditions. CONSTITUTION:Sound from a sound generator is received by a microphone 20 of a sound receiver 3. In this case, peripheral noise is included in the sound received by the microphone 20. However, a decision detector 18 of the receiver 3 passes only a special frequency through band pass filters 22a-22c and judges that the sound generator for detecting the overheated state is operated only when the state that sound pressure levels of all the special frequencies exceed the set value is continued for a predetermined time. The receiver 3 outputs a signal indicating the overheated state in which a position to be monitored out of the receiver 3 is a predetermined temperature or higher by closing a contact 29. Thus, high performance can stably be maintained for a long period.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overheat detecting device for detecting an overheated state of a main circuit conductive portion under a high electric field / high magnetic field environment such as a high voltage application state and a large current passing state in power distribution equipment. is there.

[0002]

2. Description of the Related Art In a power receiving and distributing facility, an odor detecting device has been used as a conventional overheat detecting device in order to detect an overheated state of a conductive portion due to a high electric field / high magnetic field. When the conductive part overheats, its temperature becomes extremely high.Therefore, the odor detection device is conventionally used as an overheat detection device that does not use an electric circuit etc. so that the detection device operates reliably even in such a high temperature state. It was being done. This odor detecting device was composed of an odor generating device and an odor detecting device. The odor generator is
For example, it is attached to a temperature monitored portion such as a main circuit conductive portion of a closed switchboard, and the inside of this odor generating device is filled with a substance that generates an odor (specific gas) at a set temperature or higher. On the other hand, the odor sensing device detects the peculiar gas by converting the peculiar gas generated from the odor generating device into an electric signal using an odor detection sensor that causes a resistance change due to adsorption on the surface. ..

In the odor detecting device which is the conventional overheat detecting device constructed as described above, the odor generating device is provided when the temperature monitored portion where the odor generating device is provided becomes high temperature and becomes higher than a preset temperature. The substance filled in the inside of the container generates an odor (specific gas). This peculiar gas is detected by the odor detecting sensor of the odor detecting device which is arranged apart from the temperature monitored portion. When a peculiar gas generating an odor is detected by the odor sensing device, the odor sensing device outputs an overheated state detection signal which is an electric signal, and the overheated state detection signal is used for the closed switchboard which is the temperature monitored device. It is configured to be transmitted to the outside and report the overheated state of the temperature monitored part.

[0004]

Since the conventional overheat detecting device is constructed as described above, it is possible to detect the aging of the odor-producing substance used in the odor detecting device which is the overheat detecting device and to detect the odor. Due to deterioration of the detection sensitivity due to surface contamination of the sensor and the like, stable performance could not be maintained for a long period of time, and it was necessary to replace parts frequently. Further, there is a problem that the odor sensing device has to be provided at a portion where the peculiar gas, which is the source of the odor, flows, and the installation location of the odor sensing device is limited.
The present invention has been made in order to solve the above-mentioned problems, and is capable of stably maintaining high performance for a long period of time and exposing a portion having an electric circuit to a high temperature. An object of the present invention is to obtain an overheat detecting device which can be arranged at a desired position.

[0005]

SUMMARY OF THE INVENTION An overheat detecting device according to the present invention is provided in a temperature monitored portion and operates at a temperature equal to or higher than a predetermined temperature. Sound generating means for releasing the generated mechanical energy to generate a sound having a peak level at at least one specific frequency; and a sound generated by the sound generating means, which is arranged apart from the temperature monitored portion. Sound receiving means, at least one bandpass filter that transmits only sound of a specific frequency among the output signals sensed by the sound receiving means, and overheat when the output signal of the bandpass filter satisfies a predetermined condition And a detection unit that outputs a state detection signal.

[0006]

In the overheat detecting device according to the present invention, when the temperature exceeds the set temperature, the temperature sensor used in the temperature detecting means, for example, the deformation of the bimetal, causes the accumulator used in the sound generating means, for example, the mainspring. Sound is generated by releasing the energy stored mechanically in advance, and the generated sound is sensed by the sound receiving device that is arranged at a distance, and the detection means converts it into an electric signal to output the overheat state detection signal. It is output and the overheated state of the temperature monitored part is detected.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the overheat detecting device of the present invention will be described below. FIG. 1 is a schematic side sectional view showing a case where the overheat detecting device of the present invention is applied to a closed switchboard,
In FIG. 1, the sound generating devices 2, 2, 2 of this overheat detecting device are provided respectively in the three-phase main circuit conductive parts 1, 1, 1. The sound generating device 2 includes a temperature sensor that deforms when a temperature exceeds a certain set temperature, for example, temperature detecting means having a bimetal, and a sound generating means having an energy storage device such as a spring. Further, the sound receiving device 3 of the overheat detecting device
Are separated from the main circuit conductive parts 1, 1, 1 in which the sound generating device 2 is provided. This sound receiving device 3
The microphone 20 is a sound receiving means for receiving the sound from the sound generating device 2, and the determination detector 18 is a detecting means for determining and detecting the received sound.

FIG. 2 is a side view showing the sound generator 2 of the overheat detecting device of this embodiment mounted on the main circuit conductive portion 1 which is the temperature monitored portion, and FIG. 3 is shown in FIG. It is a front view of the sound generator 2. As shown in FIG. 2, the sound generating device 2 is fixed at the connecting portion of the main circuit conductive portion 1 via a bell mounting metal fitting 5 by bolts and nuts which are the connecting means 4. A fixing plate 6 of the sound generating device 2 is screwed to the bell mounting member 5.

FIG. 4 is an exploded perspective view of the sound generator 2.
As shown in FIG. 4, a gear portion mounting plate 7 provided with a gear portion 8 is fixed to the fixed plate 6 by three pins 17, 17, 17. The gear drive shaft 13 of the gear portion 8 passes through a center hole 6a formed in the fixed plate 6 and has a mainspring 9
Is connected to the center end of. Further, one end of the mainspring winding rod 14 is fixed to the center end of the mainspring 9, and the other end of the mainspring 9 is fixed to the fixing plate 6. Therefore, the mainspring winding rod 14 is manually rotated. The moving energy is stored in the mainspring 9 by moving. The energy stored in the mainspring 9 is converted into rotational energy decelerated in the gear portion 8, and the hammer gear 10 at the final stage of deceleration of the gear portion 8 reciprocates the hammer 11 engaging with the gear tooth 10a. ing. The end of the hammer 11 that engages with the hammer gear 10 has a first pawl 11a.
And the second claw 11b are formed. When the hammer gear 10 rotates, the first claw 11a and the second claw 11b alternately engage and disengage with the groove of the gear tooth 10a of the hammer gear 10, and the hammer 11 is configured to swing around a shaft 11c.
By this swinging motion of the hammer 11, the convex portion 12a formed on the bell flange 12 is continuously hit by the protrusion 11d of the hammer 11, and the sound generating device 2 generates a sound having a vibration of a predetermined frequency.

The fixing plate 6 to which one end of the mainspring 9 is fixed is provided with a temperature detecting means which is a temperature sensor composed of a first bimetal 15 and a second bimetal 16. The first bimetal 15 is provided so as to be curved in the A direction in FIG. 4 when the temperature exceeds the set temperature, and the second bimetal 16 is provided so as to be curved in the B direction. In the normal state, the tip end 16a of the second bimetal 16 locks the hammer 11 and prohibits the swinging motion of the hammer 11. Therefore, when the first bimetal 15 is curved in the A direction and the second bimetal 16 is curved in the B direction, the tip 16a of the second bimetal 16 is released from the locked state of the hammer 11.
The hammer 11 continuously strikes the convex portion 12a of the bell flange 12 by the rotational energy stored in the mainspring 9.

FIG. 5 shows the frequency characteristics of the sound emitted when the sound generator 2 shown in FIG. 4 operates, with the horizontal axis representing frequency and the vertical axis representing sound pressure level. As shown in FIG. 5, the sound pressure of the sound emitted from the sound generator 2 of this embodiment has peak levels at 3.6 kHz, 8.1 kHz and 12.5 kHz. Generally, the sound pressure of the sound generated by such mechanical sound generating means has a plurality of peaks.
6 and 7 are a side view and a front view of the sound receiving device 3.
The sound receiving device 3 includes a microphone 20 and a judgment detector 18 which is a detection means electrically connected to the microphone 20. The judgment detector 18 selects a signal received by the microphone 20. , Has a function of determining the overheated state of the temperature monitored portion.

FIG. 8 is a block diagram showing the electrical construction of the sound receiving apparatus 3 of this embodiment. The sound received by the microphone 20 is converted into an electric signal, input to the amplifier (AMP) 21, and amplified to a predetermined level. The output signal of the amplifier 21 is input to the first bandpass filter (BPF) 22a, the second bandpass filter (BPF) 22b, and the third bandpass filter (BPF) 22c. The first bandpass filter 22a transmits only the input signal near 3.6 kHz, and the second bandpass filter 22a
b transmits only the input signal around 8.1 kHz, and the third bandpass filter 22c transmits only the input signal around 12.5 kHz. A first rectifier (AC / DC) 23a and a second rectifier (AC / DC) 23b which are respectively connected to the first bandpass filter 22a, the second bandpass filter 22b, and the third bandpass filter 22c. The third rectifier (AC / DC) 23c converts the analog signal input to each of them into a digital signal. In the setting device 25, the lowest sound pressure level of each frequency of 3.6 kHz, 8.1 kHz, 12.5 kHz in the sound emitted by the sound generating device 2 is preset, and this setting device 25 is the same as the first comparator 24a. The set sound pressure level signals of the frequencies corresponding to the second comparator 24b and the third comparator 24c are output. 3.6 kHz of the sound received by the first comparator 24a
The signal is output when the sound pressure at the frequency of is higher than the set sound pressure level, and the second comparator 24b outputs the signal when the sound pressure at the frequency of 8.1 kHz is higher than the set sound pressure level. The comparator 24c outputs a signal when the sound pressure at the frequency of 12.5 kHz is higher than the set sound pressure level. First comparator 24a, second comparator 24b, third comparator
The respective signals output from 24c are input to the AND circuit 26, and when all the signals are input, that is, when the AND condition is satisfied, the AND circuit 26 outputs the signals.
The timer (T) 27 measures the time during which the AND circuit 26 outputs the signal, and closes the contact 29 when the AND circuit 26 outputs the signal over a predetermined time.

The operation of the overheat detecting device of this embodiment constructed as above will be described. When the temperature of the main circuit conductive portion 1 which is the temperature monitored portion of the closed switchboard exceeds the set temperature, the first bimetal 15 of the sound generating device 2 is
The second bimetal because it bends in the direction of arrow A in
16 is disengaged. Therefore, the second bimetal 16
Rapidly bends in the direction of arrow B (FIG. 4), and the locked state of the hammer 11 is released. Since the mainspring 9 is in the pre-accumulated state in advance, when the locked state of the hammer 11 is released,
Rotation of the hammer gear 10 causes the hammer 11 to vibrate,
The protrusion 11d of the hammer 11 continuously hits the protrusion 12a of the bell flange 12. The sound generated at this time has a waveform having peaks equal to or higher than the set sound pressure level of the sound pressure level at frequencies of 3.6 kHz, 8.1 kHz, and 12.5 kHz.

The sound emitted from the sound generating device 2 as described above is received by the microphone 20 of the sound receiving device 3.
At this time, the sound received by the microphone 20 includes ambient noise in addition to the sound from the sound generator 2. However, the determination detector 18 of the sound receiving device 3 of the present embodiment uses the first bandpass filter 22a, the second bandpass filter 22b, and the third bandpass filter 22c to determine a specific frequency (in the case of the present embodiment, 3.6kHz, 8.1kHz, 12.5kHz), the sound generator 2 that detects the overheat condition operates only when the sound pressure level of all specific frequencies exceeds the set value for a predetermined time. Since the sound receiving device 3 is configured to determine that the sound is being received, the sound receiving device 3 is not affected by the ambient noise. When the sound receiving device 3 determines that the sound generating device 2 is operating, the sound receiving device 3
Closes the contact 29 and outputs a signal to the outside of the apparatus indicating an overheated state that the temperature monitored portion is at a predetermined temperature or higher.

In the above embodiment, the bell flange 12 is continuously struck by the hammer 11 when an overheated state is detected. However, a part of the gear teeth 10a of the hammer gear 10 is stopped so that the generated sound is stopped for a certain period of time. A notched section may be provided in the sound generator 2 to generate an intermittent sound when an overheated state is detected. FIG. 9 is a block diagram of a sound receiving device 30 of another embodiment. In FIG. 9, components having the same functions as those of the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted. In FIG. 9, the sound receiving device 30 of this embodiment includes
First comparator 24a, second comparator 24b, and third comparator 24c
Circuit having the same configuration as that of the above-mentioned embodiment by a NOR circuit 260 that takes the NOR condition of the signal from the The judging means 280 for detecting that the device 2 is operating is added to the sound receiving device 3 in the above-described embodiment. For this,
The sound received by the microphone 20 has three specific frequencies (3.6k
(Hz, 8.1kHz, 12.5kHz) has a predetermined sound pressure level, and by detecting that a specific condition that the sound of this specific frequency is paused for a predetermined time is satisfied, The sound receiving device 30 of the embodiment can more reliably detect that the sound generating device 2 is operating.

[0016]

As described above, according to the overheat detecting device of the present invention, the sound generating device having the temperature detecting means is attached to the temperature monitored part, and the sound receiving device is provided at a position separated from the temperature monitored part. By providing the sound, it is possible to reliably detect the overheated state of the temperature monitored portion by using the sound diffused in all directions as a medium, and to freely select the location of the sound receiving device. Further, since the overheat detecting device of the present invention is provided with a bandpass filter in the sound receiving device to discriminate the received sound, it is possible to obtain a highly accurate overheat detecting device that is reliable for a long period of time. There is.

[Brief description of drawings]

FIG. 1 is a schematic side sectional view showing a case where an embodiment of the present invention is applied to a closed switchboard.

FIG. 2 is a side view showing the sound generator of FIG.

3 is a front view of the sound generator of FIG.

FIG. 4 is an exploded perspective view of the sound generator of FIG.

5 is a frequency characteristic diagram of a sound generated from the sound generator of FIG.

FIG. 6 is a side view of the sound receiving device of FIG.

FIG. 7 is a front view of the sound receiving device of FIG.

8 is a block diagram of the sound receiving device of FIG.

FIG. 9 is a block diagram of a sound receiving device in an overheat detecting device according to another embodiment of the present invention.

[Explanation of symbols]

 1 Main Circuit Conductor 2 Sound Generator 3 Sound Receiver 8 Gear 9 Spring 11 Hammer 12 Bell Flange 15 First Bimetal 16 Second Bimetal 18 Judgment Detector 20 Microphone 22a First Bandpass Filter 22b Second Bandpass filter 22c third bandpass filter

Claims (1)

[Claims] 1. A temperature detecting means which is provided at a temperature monitored portion and operates at a predetermined temperature or higher, and releases at least one specific frequency by releasing mechanical energy stored in advance by the operation of the temperature detecting means. A sound generating means for generating a sound having a peak level at, a sound receiving means spaced apart from the temperature monitored part, for sensing a sound generated by the sound generating means, and a specific one of the output signals sensed by the sound receiving means At least one band-pass filter that transmits only the sound of the frequency; detection means that outputs an over-heat state detection signal when the output signal of the band-pass filter satisfies a predetermined condition; Detection device.