JP2625291B2 - Glass-lined discharge electrode - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge electrode made of glass lining and, more particularly, to a discharge electrode used for a discharge device for generating a discharge phenomenon.
Further, the present invention relates to an industrial discharge electrode required to have excellent withstand voltage characteristics and thermal shock resistance.

[0002]

2. Description of the Related Art A discharge device is a device in which a voltage is applied between a pair of discharge electrodes facing each other at an interval by a DC power supply or an AC power supply to cause a discharge phenomenon between the discharge electrodes.
This device has a function of exciting a gaseous substance and converting it into a different substance by utilizing a discharge phenomenon, and is used in various industries for substance conversion and the like. For example, obtained by converting the O ₃ when flowing O ₂ between discharge electrodes under reduced pressure, and, CO ₂
When flowing, laser light can be converted to laser light, and is therefore used for production of O ₃ , generation of laser light, and the like.

[0003] The discharge electrode for the above-mentioned discharge device is not only composed of a conductor, but is also formed by coating the surface of a conductor with a dielectric. This is because, when using only a conductor, there is a disadvantage that the discharge becomes non-uniform and the conductor is easily deteriorated. However, when the dielectric is coated, a homogeneous discharge is generated and the conductor is hardly deteriorated.

Conventionally, such discharge electrodes include a metal material (conductor) coated with plastics (dielectric), a glass or ceramics (dielectric) with a metal deposited thereon,
2. Description of the Related Art There has been known a material in which a dielectric made of a glass coating layer fused to a surface of a conductor made of metal is provided (that is, a discharge electrode made of glass lining).

[0005] Among the above-mentioned various types of discharge electrodes, those in which a metal material is coated with plastics are not baked after coating, so that the interface adhesion is not good, and the dielectric constant and heat resistance of the plastics are low. Therefore, the dielectric constant is extremely low, the thermal shock resistance is inferior, and damage or deterioration due to discharge heat is likely to occur.
Similar to the above, a metal deposited on glass or the like has a problem that the interface adhesion is not good and the dielectric constant is low, and the corrosion resistance of the deposited metal is poor and the durability is poor. On the other hand, a glass-lined discharge electrode has excellent interface adhesion and a high dielectric constant, and is the most practical and excellent among conventional discharge electrodes.

[0006]

However, the conventional glass-lined discharge electrodes have a problem that the interface adhesion is still insufficient or the dielectric constant of the glass coating layer is not uniform. The solution is desired.
That is, in a conventional glass-lined discharge electrode, the glass coating layer usually consists of one layer, and when a glass coating capable of homogenizing the dielectric constant is provided, the interfacial adhesion between the glass coating layer and the metal (conductor) of the fabric is required. Is not good.

As a countermeasure, an undercoating glass coating layer containing a ceramic powder such as silica as a burnout preventing material is provided first, and an overcoating glass coating layer is further provided thereon. A method for forming a dielectric is known. The glass-lined discharge electrode obtained by this method (hereinafter referred to as a two-layer GL electrode) functions not only as an upper coating glass coating layer but also as a lower coating glass coating layer as a dielectric. It has excellent interfacial adhesion with (conductor).

However, in this two-layer type GL electrode, the upper glass coating layer and the lower glass coating layer have different physical properties and different relative dielectric constants. Therefore, the dielectric constant of the dielectric must be reduced, and there is a new problem that the applied voltage becomes non-uniform and the withstand voltage characteristic is reduced, and the practical use as a discharge electrode is lacking. However, it is not a comprehensive solution. In particular, when the relative dielectric constant of the subbing glass coating layer is lower than that of the subbing glass coating layer, the voltage sharing applied to the subbing glass coating layer increases, so that the subbing glass coating layer has high voltage characteristics. Unless this occurs, there is a risk of dielectric breakdown and destruction of the discharge electrode.

In order to solve this problem, it is conceivable to make the relative permittivity of the upper glass coating layer equal to that of the lower glass coating layer. However, this method (hereinafter
In the proposed method), it is necessary to select a subbing glass coating layer having a relative dielectric constant equivalent to that of the upper coating glass layer, which is not always easy. There is a point. Also, even if it can be selected, the undercoating glass coating layer is not always good in terms of the adhesion to the metal (conductor) and the coating layer of the base material and the matching property of the coefficient of thermal expansion. In some cases, this method is not practical, and thus the proposed method has a drawback that its application range is limited depending on the type of metal of the upper coating glass layer and the fabric.

Furthermore, all of the above-mentioned conditions (having a relative dielectric constant equivalent to the relative dielectric constant of the overcoating glass coating layer, and good adhesion to a base metal and the like and good thermal expansion coefficient matching properties) can be satisfied. Even if an undercoating glass coating layer can be selected, it is necessary to produce a glass raw material powder for forming the undercoating glass coating layer, which causes a problem that the number of manufacturing steps is increased.

The present invention has been made in view of such circumstances, and has as its object the use of two-layer type discharge electrodes made of glass lining, which is the most practical and excellent among the conventional discharge electrodes. The purpose of the present invention is to solve the problems of the GL electrode and to provide a glass-lined discharge electrode having a high dielectric constant and excellent withstand voltage characteristics as compared with the conventional two-layer GL electrode. is there.

[0012]

In order to achieve the above object, a glass-lined discharge electrode according to the present invention has the following configuration. That is, the discharge electrode according to claim 1 is
A glass-lined discharge electrode comprising an undercoating glass coating layer containing a burn-out preventing material provided on the surface of a conductor made of metal, and a dielectric comprising an overcoating glass coating layer provided on the coating layer. A glass-lined discharge electrode, characterized in that the undercoating glass coating layer has an electric resistance of 10 ⁷ Ωcm or less.

According to a second aspect of the present invention, in the discharge electrode, the burnout preventing material contained in the undercoat glass coating layer is one or more conductive ceramic powders of silicide, boride, and carbide. It is a glass lining discharge electrode of the description.

[0014]

The glass-lined discharge electrode according to the present invention comprises:
As described above, a glass lining made by providing a subbing glass coating layer containing a burnout preventing material on the surface of a conductor made of metal, and further providing a dielectric material consisting of an upper coating glass coating layer on the coating layer A discharge electrode, wherein the undercoat glass coating layer has an electric resistance of 10 ⁷ Ωcm or less. That is, it is a two-layer type GL electrode in which the electric resistance value of the subbing glass coating layer is set to 10 ⁷ Ωcm or less.

The undercoat glass coating layer has an electric resistance of 10
Since it is as small as ⁷ Ωcm or less, it is not a dielectric, and therefore does not function as a dielectric, and only the glass coating layer functions as a dielectric. Therefore, in the glass-lined discharge electrode (two-layer GL electrode) according to the present invention, the dielectric constant is uniform, so that the dielectric constant does not decrease due to the dielectric constant inhomogeneity, and the dielectric constant is maintained at a high level. In addition, there is no reduction in withstand voltage characteristics due to non-uniformity of applied voltage. Further, no voltage is applied to the undercoat glass coating layer, so that the dielectric breakdown of the undercoat glass coating layer due to the voltage sharing does not occur. still,
The above-mentioned undercoating glass coating layer is an uppering glass coating layer (dielectric)
It has the effect of improving the interfacial adhesion between the substrate and the metal (conductor) of the fabric, and in this respect it is the same as the effect of the subbing glass coating layer in the conventional two-layer GL electrode.

Therefore, the two-layer GL electrode according to the present invention has a uniform dielectric constant, a high dielectric constant, and excellent withstand voltage characteristics as compared with the conventional two-layer GL electrode, and as a result, has excellent discharge characteristics. It can exhibit electrode characteristics.

The reason why the electric resistance value of the undercoating glass coating layer is set to 10 ⁷ Ωcm or less as described above is that when the electric resistance value exceeds 10 ⁷ Ωcm, the undercoating glass coating layer functions as a dielectric substance. This is because the effect cannot be obtained.

The electric resistance value of the undercoat glass coating layer is 10 ⁷ Ωc
m or less, what is necessary is just to select a material having conductivity as an anti-burning material to be contained in the undercoating glass coating layer,
By adding such a burnout prevention material, the electric resistance value: 10 ⁷
The undercoating glass coating layer of Ωcm or less can be easily realized, and the level of the electric resistance value can be adjusted. And these burnout prevention materials also exhibit burnout prevention function,
It also plays the role of improving the interface adhesion between the coating glass coating layer (dielectric) and the metal (conductor) of the fabric.

Examples of the anti-burnout material having such conductivity and having the function of preventing burnout include conductive ceramic powders. It is preferable to include it as an anti-burning material, and the addition thereof can easily and surely realize a subbing glass coating layer having an electric resistance value of 10 ⁷ Ωcm or less.

As described above, the two-layer GL electrode according to the present invention comprises:
Compared to the case of the conventional two-layer GL electrode, it can be manufactured only by changing the kind of the burnout prevention material, and therefore, it can be obtained by the same manufacturing process as that of the conventional two-layer GL electrode. Further, it does not have a problem as in the case of the above-mentioned proposed method. That is, in the case of the above-mentioned proposed method, there is a problem that the selection of the undercoat glass coating layer is not easy, as described above, the application range is limited, and the number of manufacturing steps is further increased. On the other hand, in the two-layer GL electrode according to the present invention, the conductive burn-out preventing material as described above may be selected, and no special selection of the subbing glass itself is required. Selection is easy,
In addition, the range of application is wide because the degree of freedom of selection is high. Furthermore, there is no need to produce special undercoating glass raw material powder,
An existing ordinary two-layer GL electrode subbing glass raw material powder may be used, so that the production process does not increase.

[0021]

【Example】

Example 1 An alkali-free silicate glass powder containing yttria, having a coefficient of thermal expansion of 90 × 10 ⁻⁷ (1 /
C), a dielectric constant of 20 and an anti-burning material made of titanium disilicide powder were mixed at a ratio of 2: 1 and JIS R 42
Specimen of the size specified in one of the 01 standards (thickness: 5mm,
Steel plate of width: 80mm, length: 80mm [SS41 steel (SS40 in Si unit)
0)] and fired at 900 ° C. to cover the undercoat glass layer (thickness: 0.2 ± 0.1 mm). The electric resistance value of this undercoat glass layer was 10 ⁷ Ωcm.

Next, an alkali-free silicate glass powder containing yttria, having a coefficient of thermal expansion of 90 × 10 ⁻⁷ (1
/ ° C) and a dielectric constant of 20 were applied to the surface of the above-mentioned undercoating glass layer, and then fired at 860 ° C to cover the overcoating glass layer (glass lining). At this time, the total thickness of the glass coating layer composed of the undercoat and the overcoat glass layers was set to the total glass thickness (0.6 ± 0.1 mm) specified in the above standard. Thus, a discharge electrode (two-layer GL electrode) according to Example 1 was manufactured.

Comparative Example 1 A discharge electrode (2) according to Comparative Example 1 was prepared in the same manner as in Example 1 except that silica powder was used in place of the titanium disilicide powder as a burn-out preventing material. (Layered GL electrode). At this time, the electric resistance value of the undercoat glass layer was 10 ¹³ Ωcm.

Comparative Example 2 A discharge electrode (single-layer GL) according to Comparative Example 2 was formed in the same manner as in Example 1 except that the undercoating glass layer was not covered and only the overcoating glass layer was covered. Electrodes).

[0025] Embodiment 1, the discharge electrode according to Comparative Example 1 and 2, JISR 4201 voltage resistance test as defined in one standard (breakdown voltage measurement test), AC: relative dielectric constant at 10 ⁵ Hz , And an adhesion test by a steel ball drop method. As a result, the single-layer GL electrode according to Comparative Example 2 had a relative dielectric constant of 20, but had a breakdown voltage of 16 KV / mm, and cracked at 10 N · m in the adhesion test. The two-layer GL electrode according to Comparative Example 1 had a breakdown voltage of 20 KV / mm, but had a low relative dielectric constant of 12, and cracked at 30 N · m. In contrast, the two-layer GL electrode according to Example 1 had a relative dielectric constant of 20 and a breakdown voltage of 20 KV / mm.
Cracks did not occur even at 30 N · m, and all were at an excellent level.

(Example 2) An SS41 steel tube having an outer diameter of 25 mm and a length of 1000 mm was used in place of the SS41 steel sheet of Example 1 above, and an upper glass layer was formed in the same manner as in Example 1 except for this point. And the coating of the undercoating glass layer, and the two-layer GL according to Example 2
Electrodes were made. The relative permittivity and the like of the discharge electrode are the same as those according to the first embodiment. In addition, no spark was generated at 20 KV in the high voltage pinhole test.

After processing the electrode according to Example 2, a discharge experiment in which an AC voltage of 8 KV was applied and cooling water was allowed to flow in the tube was continuously performed. As a result, no abnormality such as electric breakdown of the glass coating layer was observed.

[0028]

The glass-lined discharge electrode (two-layer type GL electrode) according to the present invention has the above-described structure and functions, and is the most practical and conventional among the conventional discharge electrodes. Two-layer type with excellent glass-lined discharge electrodes
The conventional two-layer GL solves the problems of the GL electrode.
Compared to the electrodes, the dielectric constant can be made uniform, the dielectric constant can be made high, and the applied voltage becomes uniform and the withstand voltage characteristics are excellent, so the discharge performance of the discharge device that causes the discharge phenomenon In addition, there is an effect that the life can be greatly improved.

Further, the two-layer GL electrode according to the present invention can be obtained by the same manufacturing steps as in the case of the conventional two-layer GL electrode, which leads to an increase in the number of manufacturing steps as in the case of the above-mentioned proposed method. It can be manufactured without. Moreover, it does not have the problems as in the case of the above-mentioned proposed method, and has a two-layer GL compared to the case of the above-mentioned proposed method.
It is easy to select the subbing glass coating layer of the electrode, and also has the effect that the range of application is wide because the degree of freedom in the selection is high.

 ──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Tatsuo Hara 6-4-10-101 Sumiyoshinomiyacho, Higashinada-ku, Kobe (56) References JP-A-4-257281 (JP, A) JP-A-4-257280 (JP, A) JP-A-1-242403 (JP, A) JP-A-58-115004 (JP, A) JP-A-64-21980 (JP, A) JP-A-1-2055583 (JP, A) JP-A-61-224379 (JP, A) JP-A-62-44566 (JP, A) JP-A-2-142436 (JP, U)

Claims (2)

(57) [Claims] 1. A glass lining comprising: an undercoat glass coating layer containing a burnout preventing material provided on a surface of a conductor made of metal; and a dielectric material comprising an overcoat glass coating layer provided on the coating layer. A glass-lined discharge electrode, wherein the undercoat glass coating layer has an electric resistance of 10 ⁷ Ωcm or less. 2. The glass-lined discharge electrode according to claim 1, wherein the burnout preventing material contained in the undercoat glass coating layer is one or more kinds of conductive ceramic powders of silicide, boride, and carbide. .