JPH06118055A - Detecting sensor for sf6 cracked gas - Google Patents

Abstract

PURPOSE:To provide a detecting sensor for SF6 cracked gas capable of detecting the internal abnormality of a SF6 gas insulated electric apparatus with a simple method. CONSTITUTION:When a ceramic plate 1 absorbs an active SF6 cracked gas such as SF4, HF, a spontaneous current is carried between electrodes 2, 3 of different metals. Since this value is greatly influenced by the ceramic material, the porosity 5-40%, and the pore diameter 5-50mum are limited, or the composition is limited.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a sensor capable of detecting an internal abnormality of SF ₆ gas-insulated electric equipment by detecting deterioration of SF ₆ (sulfur hexafluoride) gas.

[0002]

BACKGROUND OF THE INVENTION SF ₆ SF ₆ gas insulated electrical apparatus in which the gas is sealed, with energy at the time of abnormality when the abnormality in the apparatus main body occurs, gases such as in SF ₆ gas is thermally decomposed SF _4, HF can Since they are generated, it is possible to confirm the abnormality of the SF ₆ gas-insulated electric equipment by detecting these SF ₆ decomposed gases.

As a method for detecting the decomposition of SF ₆ gas,
In general, to collect the SF ₆ gas insulated electrical apparatus inside the SF ₆ gas, gas chromatography, and analyzed by ion chromatography, a method of confirming an abnormality is widely put into practical use.

Several methods have been proposed for detecting anomalies online or in a manner similar to the equipment. For example, JP-B-60-14152 and JP-B-63-4087.
Japanese Patent Publication No. 5 discloses a method of disposing an adsorbent at a position communicating with the gas in the device. Also, for example, Japanese Patent Publication Sho 6
In Japanese Patent Publication No. 0-14152, the dielectric properties of the adsorbent when SF ₆ decomposition gas is adsorbed, are disclosed in JP-B-63-4087.
Japanese Patent Publication No. 5 discloses a method of detecting an abnormality in a gas-insulated electric device from a color change.

Further, for example, in Japanese Examined Patent Publication (Kokoku) No. 1-100444 or Japanese Examined Patent Publication (Kokoku) No. 64-12807, the conductivity of the metal thin film disposed on the insulating film is lowered, so that the abnormality of the SF ₆ gas-insulated electrical equipment is detected. A method of detecting is disclosed.

[0006]

However, the generally used method by gas analysis has a problem that it takes a lot of manpower and time from the collection of gas to the output of the analysis result. Further, since the SF ₆ decomposed gas is active and easily reacts chemically, if the time from the collection of gas to the analysis is long, a part of the gas chemically reacts, and accurate analysis cannot be performed. There were problems such as.

Further, the method disclosed in the above-mentioned patent publication has the following problems. Japanese Patent Sho 60-1
The method disclosed in Japanese Patent No. 4152 requires a means for applying a constant voltage to the electrodes arranged on the adsorbent,
The device becomes complicated. Further, in the method disclosed in Japanese Patent Publication No. 63-40875, it is necessary to detect the degree of discoloration of the adsorbent for online monitoring, but no good method has been found.

According to the method disclosed in Japanese Patent Publication No. 1-100444 or Japanese Patent Publication No. 64-12807, it is necessary to stack an insulating film and a metal thin film on a substrate, which makes it difficult to manufacture the device. The method disclosed in Japanese Patent Publication No. Sho 60-14152 requires a constant voltage device.

The present invention has been made to solve the above-mentioned problems, and an internal abnormality of SF ₆ gas-insulated electrical equipment or the like can be detected early by a simple method.
The purpose is to obtain a sensor for detecting F ₆ decomposed gas.

[0010]

S according to the invention of claim 1
The F ₆ decomposed gas detection sensor is limited to a ceramic having a porosity of 5 to 40% and a pore diameter of 5 to 50 μm.

In the sensor for detecting SF ₆ decomposed gas according to the second aspect of the present invention, the composition of the ceramic is zinc oxide 15-40.
% By weight, silica 10-20% by weight, boric acid 8-25% by weight, cordierite 12-15% by weight, synthetic mica 20-
It is composed of 50% by weight.

In the sensor for detecting SF ₆ decomposed gas according to the third aspect of the present invention, the two kinds of metal film electrodes on the surface of the ceramic plate for adsorbing the SF ₆ decomposed gas are faced in a comb shape. .

The sensor for detecting SF ₆ decomposed gas according to the invention of claim 4 has a large number of through holes each having a small diameter in the thickness direction and has two kinds of different kinds above and below the plane of the ceramic plate for adsorbing the SF ₆ decomposed gas. The metal is fixed as an electrode.

In the sensor for detecting SF ₆ decomposed gas according to the fifth aspect of the present invention, two spiral grooves are provided in parallel on a ceramic rod, and dissimilar metal electrode wires are wound around the grooves.

[0015]

According to the invention of claim 1, the ceramic material is S.
When an active SF ₆ decomposition gas such as F ₄ or HF is adsorbed, a spontaneous current flows between the electrodes of dissimilar metals on this surface, and the value of this spontaneous current is greatly influenced by the ceramic material, and the porosity is 5 -40%, the pore size increases with increasing adsorption area only when the pore size is 5-50 μm.

According to the second aspect of the present invention, the value of the spontaneous current is greatly influenced by the ceramic material as described above, and the above composition range in which the SF ₆ decomposition gas adsorption efficiency is good is useful and exceeds the range. Therefore, a dense sintered product cannot be obtained or the machinability is poor. Further, the compounds of zinc oxide and boric acid and the compounds of zinc oxide and silica, which compose the ceramic, partially react with each other when adsorbing the active SF ₆ decomposition gas, and the electric resistance decreases, so that the spontaneous current value generated between the electrodes is Increase.

According to the invention of claims 3 to 5, when the ceramic material adsorbs an active SF ₆ decomposition gas such as SF ₄ and HF, a spontaneous current flows between the electrodes of different metals, and the value of this spontaneous current is It is greatly affected by the shape of the electrodes formed on the ceramic surface, and if the gap between the electrodes is constant, it will increase in proportion to the electrode length of the facing electrode portions, so the electrode length will be increased to improve sensitivity. .

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows SF _{6 according} to Embodiments 1 to 8 of the present invention.
It is a figure showing the basic composition of the sensor for detection of decomposition gas, and the composition of the test device. In FIG. 1, 1 is an electrically insulating ceramic plate, 2 is, for example, a gold electrode, 3 is, for example, an aluminum electrode, and the electrodes 2 and 3 have a certain interval (electrode gap) on the plate surface of the ceramic plate 1. The metal film is arranged in this manner. Reference numeral 4 is a lead wire connected to each of the electrodes 2 and 5, reference numeral 5 is a container in which the sensor for detecting SF ₆ decomposed gas composed of reference numerals 1 to 3 is stored, and 6 is for sealing SF ₆ gas in the container 5. Is a connecting pipe connected from the gas pump 6 into the container 5, and 8 is a voltmeter connected to the lead wire 4.

The operation of the sensor for detecting SF ₆ decomposed gas having the above structure will be described. SF ₆ gas is enclosed in the container 5 by the gas pump 6 through the connecting pipe 7. This SF ₆
When the decomposed gas component is present in the gas, the decomposed gas component is adsorbed by the ceramic plate 1 and a potential difference generated between the electrodes 2 and 3 causes a current to spontaneously flow, which flows through the lead wire 4 and the voltmeter 8 Is measured. If there is no decomposition gas in the SF ₆ gas, the voltage generated between the electrodes 2 and 3 is almost zero, and the voltage measured by the voltmeter 8 is almost zero.

Example 1. As the ceramic plate 1, mullite having a porosity of 10% and a pore diameter of 20 to 30 μm was used.

Example 2. As the ceramic plate 1, an alumina sintered product having a porosity of 30% and a pore diameter of 5 to 20 μm was used.

Example 3. As the ceramic plate 1, a cordierite sintered product having a porosity of 30% and a pore diameter of 20 to 50 μm was used.

As Comparative Example 1-1, a mullite sintered product having a porosity of 50% and a pore diameter of 20 to 50 μm, and as Comparative Example 1-2, an alumina sintered product having a porosity of 20% and a pore diameter of 50 to 100 μm. 1 shows an alumina sintered product having a porosity of 10% and a pore diameter of 3 μm as Comparative Example 1-3, and an alumina sintered product having a porosity of 3% and a pore diameter of 10 to 20 μm as Comparative Example 1-4. The same apparatus as shown was used as a ceramic plate of a sensor for detecting SF ₆ decomposed gas.

The distance between the electrode gaps during the production of the electrodes was measured with a coordinate measuring machine. Examples of the gap distance are from Example 1
In 3 and Comparative Examples 1-1 to 1-4, it was manufactured to have a thickness of 0.5 mm. Also, the accuracy of the electrode gap is good (± 0.1
mm) in the new SF ₆ gas, after the SF ₆ decomposition gas was exposed for 30 minutes, and after the decomposition gas was exposed, the spontaneous emission currents after vacuuming the inside of the container 5 and removing the decomposition gas are shown in FIG. It was determined by the device shown in. In addition, the spontaneous current is a voltmeter 8
The voltage obtained in Step 2 is measured by the impedance of the voltmeter 8 (1 × 10
⁶ Ω). Table 1 below shows the measured values of the distance between the electrode gaps and the spontaneous current.

[0025]

[Table 1]

The spontaneous current is generated only when the SF ₆ decomposed gas comes into contact with the ceramic plate 1, and in Comparative Example 1-1, the accuracy of the electrode gap is lowered and the metal electrodes are short-circuited. In Comparative Example 1-2 as well, the accuracy between the electrode gaps decreases,
There is a sufficient possibility that the same problem as in Comparative Example 1-1 will occur. Further, in Comparative Examples 1-3 and 1-4, the accuracy of the electrode gap is improved, but the amount of spontaneous current generated is in Examples 1 to 3 (10).
^{-Compared to 7} A), it is very small.

From the results shown in Table 1, the ceramic plate 1 used in the sensor for detecting SF ₆ decomposed gas is SF ₄ , HF.
It was found that a spontaneous current flows between the electrodes 2 and 3 made of different metals when adsorbing an active SF ₆ decomposition gas such as, and the value of the spontaneous current is greatly influenced by the material of the ceramic plate 1.

That is, it was found that the spontaneous current was relatively large only when the material of the ceramic plate 1 had a porosity of 5 to 40% and a pore diameter of 5 to 30 μm.
The ceramic plate 1 is an electrically insulating ceramic such as alumina,
Any cordierite, mullite, forsterite or the like having a normal insulation resistance of 10 ¹⁰ Ω or more may be used.

When the pore diameter of the ceramic material is 5 μm or less, the spontaneous current value is too small to detect SF ₆ decomposed gas. When the pore size is 50 μm or more,
Adhesion with the metal electrode and dimensional accuracy of the electrode are reduced, which is not preferable for downsizing the sensor. If the porosity of the ceramic material is 5% or less, the amount of adsorbed SF ₆ decomposed gas is small and the value of the spontaneous current is small, so that the SF ₆ decomposed gas cannot be detected. Also, when the porosity is 40% or more, the adhesion to the electrode and the dimensional accuracy of the electrode are deteriorated, which is not preferable in downsizing the sensor.

That is, an electrically insulating ceramic material characterized in that the ceramic plate 1 shown in FIG. 1 has a porosity of 5 to 40% and a pore diameter of 5 to 50 μm detects SF ₆ decomposition gas by spontaneous current. It was found to be useful as a sensor material.

Although the mechanism of generating the spontaneous current has not been clarified, ionization of the metal occurs in the electrode portion on the ceramic, a potential difference is generated due to the difference in the ionization tendency of the metal, and the spontaneous current flows between the electrodes. The value of this spontaneous current is estimated to have a positive correlation with the amount of SF ₆ decomposition gas adsorbed on the ceramic plate.

Example 4. The ceramic plate 1 shown in FIG. 1 has a compounding ratio of zinc oxide 36.6% by weight, silica 8.4% by weight, boric acid 11.3% by weight, cordierite 5.7% by weight, and synthetic mica 38.0% by weight. After mixing, a fired ceramic plate was used.

Example 5. Similarly, as the ceramic plate 1,
Zinc oxide 40.0% by weight, silica 10.0% by weight, boric acid 16.0% by weight, cordierite 14.0% by weight, and synthetic mica 20.0% by weight were mixed and mixed, and then the fired ceramic plate was mixed. used.

Example 6. Similarly, as the ceramic plate 1,
A mixture of zinc oxide (20.0% by weight), silica (10.0% by weight), boric acid (14.0% by weight), cordierite (6.0% by weight), and synthetic mica (50.0% by weight) was mixed and fired to obtain a ceramic plate. used.

Example 7. Similarly, as the ceramic plate 1,
A ceramic plate that was burned after mixing at a compounding ratio of 15.0 wt% zinc oxide, 10.0 wt% silica, 25.0 wt% boric acid, 10.0 wt% cordierite, and 40.0 wt% synthetic mica was used. used.

Example 8. Similarly, as the ceramic plate 1,
A mixture of zinc oxide (30.0% by weight), silica (20.0% by weight), boric acid (10.0% by weight), cordierite (10.0% by weight) and synthetic mica (30.0% by weight) was mixed and then fired to obtain a ceramic plate. used.

As Comparative Example 2-1, zinc oxide 10.0% by weight, silica 20.0% by weight, boric acid 20.0% by weight, cordierite 10.0% by weight, synthetic mica 40.0% by weight.
A ceramic plate that had been fired after being mixed with was used. Comparative example 2
-2, zinc oxide (50.0% by weight), silica (10.0% by weight), boric acid (10.0% by weight), cordierite (5.0% by weight) and synthetic mica (25.0% by weight) were mixed and fired to obtain a ceramic plate. used. Zinc oxide 3 as Comparative Example 2-3
0.0% by weight, silica 30.0% by weight, boric acid 10.0
% By weight, cordierite 5.0% by weight, synthetic mica 25.
A ceramic plate that was fired after mixing at 0% by weight was used.

As Comparative Example 2-4, after mixing with 40.0% by weight of zinc oxide, 5.0% by weight of silica, 15.0% by weight of boric acid, 10.0% by weight of cordierite and 30.0% by weight of synthetic mica. A fired ceramic plate was used. Comparative Example 2-
5 as zinc oxide 35.0% by weight, silica 15.0% by weight, boric acid 5.0% by weight, cordierite 5.0% by weight,
A ceramic plate was used which was mixed with 40.0% by weight of synthetic mica and then calcined. Zinc oxide 25.0 as Comparative Example 2-6
%, Silica 10.0%, boric acid 30.0%, cordierite 5.0% by weight, and synthetic mica 30.0% by weight, and a fired ceramic plate was used.

As Comparative Example 2-7, zinc oxide 25.0% by weight, silica 10.0% by weight, boric acid 15.0% by weight, cordierite 20.0% by weight, synthetic mica 30.0% by weight.
A ceramic plate that had been fired after being mixed with was used. Comparative example 2
As -8, zinc oxide 35.0% by weight, silica 15.0% by weight, boric acid 15.0% by weight, cordierite 0.0% by weight, synthetic mica 35.0% by weight were mixed, and then the fired ceramic plate was mixed. used. Zinc oxide 2 as Comparative Example 2-9
0.0 wt%, silica 10.0 wt%, boric acid 8.0 wt%, cordierite 2.0 wt%, synthetic mica 60.0
A ceramic plate that had been fired after mixing in wt% was used.

As Comparative Example 2-10, zinc oxide 40.0
% By weight, silica 20.0% by weight, boric acid 20.0% by weight, cordierite 10.0% by weight, synthetic mica 10.0
A ceramic plate that had been fired after mixing in wt% was used. As Comparative Example 2-11, a commercially available alumina (96%) ceramic plate was used.

The accuracy of the electrode gap when the electrode gap distance between the electrodes 2 and 3 on the ceramic plate 1 was set to 0.5 mm was measured by a coordinate measuring machine as shown in Table 2. . In Comparative Examples 2-1 to 2-9, the gap accuracy of the electrodes is low, and a short circuit may occur between the electrodes.

[0042]

[Table 2]

Also, the accuracy of the above-mentioned electrode gap is good (±
0.1 mm) in new SF ₆ gas, and SF ₆
Spontaneous currents after the decomposition gas was exposed for 30 minutes and after the decomposition gas was exposed to a vacuum in the container 5 to remove the SF ₆ decomposition gas were obtained. For the spontaneous current, the voltage obtained by the voltmeter is the impedance of the voltmeter (1 x 10Ω).
I asked for it except. The measured values are shown in Table 3, and the ceramic sensor of the present invention occurs only when the decomposed gas comes into contact with the ceramic plate, and as can be understood from Comparative Example 2-11, the material within the range defined by the present invention. Only a large spontaneous current is generated.

[0044]

[Table 3]

As can be understood from the results shown in Tables 2 and 3, the ceramic plate material is composed of zinc oxide, silica, boric acid, cordierite, and synthetic mica. It was found that the value of the spontaneous current of the sensor for detecting SF ₆ decomposed gas was remarkably large in the case of ceramics. This ceramic plate is an electrically insulating ceramic and has a normal insulation resistance of 1
0 is ¹⁰ or more of those.

The composition ratio of zinc oxide is preferably 15 to 40% by weight. If it is more or less than this, a dense sintered product cannot be obtained, and the adhesiveness of the electrode and the dimensional accuracy of the electrode are deteriorated, which is not preferable in downsizing the sensor. The composition ratio of boric acid is preferably 8 to 25% by weight, and the composition ratio of silica is also preferably 10 to 20% by weight. If silica and boric acid are both larger or smaller than the above composition ratios, a dense sintered product like zinc oxide cannot be obtained, which is not preferable.

The cordierite content is preferably 2 to 15% by weight. Even if it is less than this, if it is more than this, a dense sintered product cannot be obtained, which is not preferable. 20 to 5 synthetic mica
It is preferably 0% by weight. If it is more than this, a dense sintered product cannot be obtained, and if it is less than this, the machinability is poor, and it is difficult to form a predetermined shape, which is not preferable.

That is, it has a composition of 15 to 40 wt% zinc oxide, 10 to 20 wt% silica, 8 to 25 wt% boric acid, 2 to 15 wt% cordierite, and 20 to 50 wt% synthetic mica. Electrically insulating ceramic material is S
It has been found that it is useful as a sensor element material for detecting F ₆ decomposition gas by spontaneous current.

Although the mechanism of generation of a spontaneous current between different metal electrodes due to adsorption of active SF ₆ decomposition gas such as SF ₄ , HF has not been clarified, the ceramic plate having the above composition is hydrolyzed by SF ₄ , HF and the like. When it adsorbs the SF ₆ decomposed gas, it acts as a solid electrolyte medium. Therefore, it is presumed that ionization of the metal occurs at the electrode portion, a potential difference is generated due to the difference in the ionization tendency of the metal, and a spontaneous current flows between the electrodes.

Further, the compounds of zinc oxide and boric acid and the compounds of zinc oxide and silica, which compose the ceramic of the present invention, partially react when adsorbing the active SF ₆ decomposition gas and the electric resistance is lowered, so that the interelectrode electrode is reduced. It is also presumed that the spontaneous current value that occurs in 1 increases. Further, it is considered that the synthetic mica and cordierite also react with the SF ₆ decomposed gas to lower the electric resistance, but it is not clear in the present state of the reaction forms in detail.

Example 9. 2A and 2B are a plan view (FIG. 2A) and a side view (FIG. 2B) of the sensor for detecting SF ₆ decomposed gas according to the present embodiment. In FIG. 2, 1A is a flat plate whose length and width are, for example, 40 mm each. Shaped ceramic plate, and an electrode 2A made of a dissimilar metal film on the upper surface of the ceramic plate 1A,
The shape of 3A is faced in a comb shape, and the distance between the electrodes 2A and 3A (distance between electrode gaps) is 0.5 mm.

Example 10. FIG. 3 shows SF ₆ according to this embodiment.
FIG. 3 is a plan view (FIG. 3A) and a side view (FIG. 3B) of the decomposed gas detection sensor. In FIG. 3, 1B is a flat plate having a length and width of, for example, 40 mm and a diameter of 0.1 to 1. A ceramic plate having a large number of 0 mm through holes 9 in the thickness direction in a matrix, 2B is an electrode made of, for example, a gold metal film fixed to the entire upper surface of the ceramic plate 1B, and 3B is the ceramic plate 1.
It is an electrode of a metal film made of, for example, aluminum fixed to the entire lower surface of B.

Example 11. FIG. 4 shows SF ₆ according to this embodiment.
4A and 4B are a front view (FIG. 4A) and a partially enlarged view (FIG. 4B) of a sensor for detecting decomposed gas. In FIG. 4, 1C is a round rod-shaped ceramic rod, 1C ₁ and 1C ₂ are ceramic rods 1.
Spiral grooves 2C and 3C provided in a spiral shape in parallel with the C surface in the form of _two spiral grooves 1C ₁ and 1C ₂
Is a dissimilar metal electrode wire of, for example, gold and aluminum, which is wound so as to face each other.

The materials of the ceramic plates 1A and 1B and the ceramic rod 1C listed in the above Examples 9 to 11 have the same porosity of 5 to 40% and the pore diameter of 5 to 50 as in Examples 1 to 3.
First condition of μm, zinc oxide 15 similar to those in Examples 4 to 8
-40 wt%, silica 10-20 wt%, boric acid 8-2
5% by weight, cordierite 2-15% by weight, synthetic mica 2
It is more preferable that at least one of the second conditions of the composition composed of 0 to 50% by weight is satisfied, and Example 9
In Nos. 11 to 11, the first condition is satisfied.

FIG. 5 shows a comparative example 3 with respect to Examples 9 to 11.
The front view of the sensor for detecting SF ₆ decomposed gas of No. 1 (Fig. 5
(A)) and a side view (FIG. 5 (b)). 1D is a flat ceramic plate having a length and width of 40 mm, and 2D and 3D face each other with a gap of 0.5 mm on the upper surface of the ceramic plate 1D. For example, the electrode is made of a dissimilar metal film of gold and aluminum. The ceramic plate 1D was made of the same material as the ceramic used in Examples 9 to 11.

[0056] The SF ₆ decomposition gas sensing sensor shown in SF ₆ decomposition gas detection sensors and Comparative Examples 3-1 shown in Examples 9-11 in the same configuration as that of FIG. 1, the new SF ₆ gas, and discharge Each spontaneous current after exposure to the decomposed SF ₆ decomposed gas for 30 minutes was measured. The spontaneous current was obtained by dividing the voltage obtained by the voltmeter by the impedance of the voltmeter (1 × 10 ⁶ Ω).

[0057]

[Table 4]

The measured values are shown in Table 4 above.
The sensor for detecting F ₆ decomposed gas generates a spontaneous current only when the SF ₆ decomposed gas comes into contact with the ceramic. The shape of the SF ₆ decomposed gas detection sensor shown in FIGS. 2 and 3 is shown in FIG.
Compared with the comparative example of the sensor shown in, the spontaneous current value obtained from the ceramic material of the same size and the same material is increased by about one digit, and the shape of the SF ₆ decomposition gas detection sensor shown in FIG. 4 is also enlarged. However, a larger spontaneous current can be obtained as compared with the sensor of Comparative Example 3-1.

Since the value of this spontaneous current increases in proportion to the electrode length of the facing electrode portion when the gap between the electrodes is constant, the sensitivity of the sensor can be improved by increasing the electrode length.

Although gold and aluminum are used as the electrode material in each of the above-mentioned embodiments, it is needless to say that the same effect can be obtained by combining other metals as long as they are different metals.

[0061]

As described above, according to the present invention, the ceramic has a porosity of 5 to 40% and a pore diameter of 5 to 50 μm, or the composition of the ceramic is 15 to 40% by weight of zinc oxide. %, Silica 10 to 20% by weight, boric acid 8 to 25% by weight, cordierite 12 to 15% by weight, synthetic mica 20 to 50% by weight, or the facing electrode portion on the ceramic surface. since it is configured to SF ₆ decomposition gas detection sensors so as to increase the electrode length, the sensitivity can be improved by increasing the self power generation flow is measured SF ₆ during decomposition gas generation, the SF ₆ gas insulated electrical apparatus By using the device for detecting an abnormality, it is possible to easily and accurately detect the abnormality of the SF ₆ gas-insulated electric equipment.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a sensor for detecting SF ₆ decomposed gas and a test apparatus therefor according to Examples 1 to 8 of the present invention.

FIG. 2 is a diagram showing the structure of a sensor for detecting SF ₆ decomposed gas according to Example 9 of the present invention.

FIG. 3 is a diagram showing the structure of a sensor for detecting SF ₆ decomposed gas according to Example 10 of the present invention.

FIG. 4 is a diagram showing the structure of a sensor for detecting SF ₆ decomposed gas according to Example 11 of the present invention.

FIG. 5 is a diagram showing a configuration of a sensor for detecting SF ₆ decomposed gas in a comparative example.

[Explanation of symbols]

1, 1A, 1B Ceramic plate 2, 3, 2A, 3A, 2B, 3B Electrode 9 Through hole 1C Ceramic rod 1C ₁ , 1C ₂ Spiral groove 2C, 3C Dissimilar metal electrode wire

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Tadayoshi Murakami 8-1-1 Tsukaguchi Honcho, Amagasaki City, Hyogo Prefecture Sanryo Electric Co., Ltd. Production Technology Laboratory (72) Inventor Yoshihiro Makino 651 Tenwa, Ako City, Hyogo Prefecture Address Mitsubishi Electric Co., Ltd. Ako Plant (72) Inventor Hideo Shinohara 651 Tenwa, Ako City, Hyogo Prefecture Mitsubishi Electric Co., Ltd. Ako Plant

Claims (5)

[Claims] 1. Adsorbing SF ₆ decomposition gas and having a porosity of 5
It has a structure in which two kinds of metal electrodes are arranged on a ceramic surface having a pore size of ˜40% and a pore diameter of 5 to 50 μm so as to have a certain interval, and it is possible to detect deterioration of SF ₆ gas by a spontaneous current. Characteristic SF ₆ decomposed gas detection sensor. 2. Zinc oxide 15-40% by weight, silica 10
~ 20 wt%, boric acid 8-25 wt%, cordierite 1
2-15 wt%, having arranged structure so as to have a spacing in the two kinds of metal electrodes on a ceramic surface having a composition composed of a synthetic mica 20-50 wt%, SF ₆
SF characterized by detecting gas deterioration by spontaneous current
₆ Sensor for detecting decomposed gas. 3. A structure in which two kinds of metal film electrodes are arranged on a surface of a ceramic plate for adsorbing SF ₆ decomposed gas so as to have a certain interval, and the electrode shapes face each other in a comb shape. A sensor for detecting SF ₆ decomposed gas, which is characterized by detecting deterioration of SF ₆ gas by a spontaneous current. Wherein the thickness direction of the small diameter of the through hole to have a large number and SF ₆ decomposition gas two dissimilar metals sticking to the electrode and without the top and bottom of the plane of the ceramic plate to adsorb, SF ₆ gas A sensor for detecting SF ₆ decomposed gas, which is characterized by detecting deterioration by spontaneous current. 5. A ceramic rod for adsorbing SF ₆ decomposed gas is provided with two spiral grooves in parallel, and dissimilar metal electrode wires are wound around the groove so as to detect deterioration of SF ₆ gas by spontaneous current. A sensor for detecting SF ₆ decomposed gas.