JPH0262309B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric field curtain device, and more particularly to an electric field curtain device with improved dielectric strength.

A conventional single-phase exposed electric field curtain sheet will be explained with reference to FIGS. 1 and 2. Figure 1 is a plan view of a single-phase exposed curtain sheet, and Figure 2 is a -
A part of the line cross section is shown. As is clear from FIG. 2, on the insulating support layer 3, the buried electrode group 5 (V phase),
6 (W phase) are provided parallel to each other with a predetermined interval maintained. An internal dielectric layer 2 is provided on the insulating support layer 3 and the buried electrode groups 5 and 6 so as to cover them, and a surface dielectric layer 1 is further provided thereon. On this surface dielectric layer 1 is an exposed electrode group 4.
(U phase) is provided parallel to the buried electrode groups 5 and 6. Reference numerals 7, 8, and 9 are distribution electrodes connected to the exposed electrode group 4 and the buried electrode groups 5 and 6, respectively. Furthermore, electrode terminals 10, 11, and 12 are connected to the respective ends of the exposed electrode group 4 and the buried electrode groups 5 and 6.

It is known that the conventional single-phase exposed electric field curtain sheet having the above-mentioned structure is weak in the following two places in terms of withstand voltage.

(1) The end of the sheet where the exposed electrode group 4 and the distribution electrode 8 intersect three-dimensionally with the surface dielectric layer 1 interposed (the area marked by diagonal lines A in FIG. 1).

(2) Near the end of each electrode group 4, 5, 6, especially the part of the surface dielectric layer 1 immediately above the end of the buried electrode group 5 (the area marked by diagonal line B in FIG. 1).

Among these, problem (1) was completely overcome through research by the present inventors by taking measures as shown in FIG.

FIG. 3 shows a sectional view taken along the line Y--Y in FIG. A layer with a thickness of approximately 500 μm is provided between the internal dielectric layer 2 and the surface dielectric layer 1 at the portion where the distribution electrode 8 for the buried electrode group 5 formed on the insulating support layer 3 and the exposed electrode group 4 intersect three-dimensionally. An insulator layer 13 made of silicone rubber is provided. By providing this insulating layer 13, the withstand voltage is improved and there is no fear that dielectric breakdown will occur at the three-dimensional intersection portion.

Next, the withstand voltage of the above part (2) will be explained. FIG. 4 shows an enlarged view of a part of the shaded area B in FIG. In FIG. 4, exposed electrode groups 4a, 4b,
4c...... and buried electrode groups 5a, 5b, 5c...
The degree of electric field concentration is significantly greater at the end of the electrode than in other parts, especially in the exposed electrode groups 4b and 4c.
A large amount of ions are released from the end of .
Many of these ions or electrons are generated along the lines of electric force formed between the ends of the exposed electrode groups 4b, 4c, where the electric field density is particularly high, and the ends of the buried electrode groups 5b, 5c,... It is accelerated.

Now, the electrical relationship between the exposed electrode group 4 and the buried electrode group 5 can be roughly represented by an equivalent circuit as shown in FIG. That is, as the first circuit,
From the exposed electrode group 4 through the surface of the surface dielectric layer 1,
There is one in which a resistor R1 extending directly above the buried electrode group 5 and a resistor R2 extending vertically through the surface dielectric layer 1 and the internal dielectric layer 2 from directly above the buried electrode group 5 to the buried electrode group 5 are connected in series. As a second circuit, from the exposed electrode group 4, the surface dielectric layer 1 and the inner dielectric layer 2
The resistance R that penetrates through and directly reaches the buried electrode group 5
It consists of 3.

Among these resistances R1, R2, and R3, the resistance R1+R2 that passes through the interface between the surface dielectric layer 1 and the outside air or through the outside air and reaches the buried electrode group 5 is higher than the resistance R3 that penetrates inside the surface dielectric layer 1. has a much smaller impedance. For this reason, ions, oxygen radicals, and/or electrons generated from the end of the exposed electrode group 4 are accelerated through the interface or in the outside air near the interface and are injected onto the surface dielectric layer 1 directly above the end of the buried electrode group 5. There will be a collision. For this reason, the portion of the surface dielectric layer 1 directly above the buried electrode group 5 deteriorates and wears more severely than other portions, and a hole is formed through this portion in a relatively short period of time. In this case, the impedance between the ends of the exposed electrode group 4 and the buried electrode group 5 is drastically reduced, resulting in a drawback that spark discharge occurs between the ends of the exposed electrode group 4 and the buried electrode group 5.

An object of the present invention is to eliminate the above-described drawbacks of the conventional electric field curtain sheet, thereby extending its life and improving safety.

A feature of the present invention is to stop or reduce the generation of ions and electrons from the ends of the electrode group by covering the surface of the electric field curtain device located at the ends of the electric field curtain electrodes with an insulator, and to stop or reduce the generation of ions and electrons from the ends of the electrode group. The point is that the impedance is extremely large.

The present invention will be explained below with reference to Examples.

FIG. 6 shows one embodiment of the present invention, and is a plan view of a single-phase exposed type three-phase electric field curtain sheet. Also,
FIG. 7 shows a sectional view taken along the Z-Z line in FIG. 6.

Among the three electrode groups 4, 5, and 6, exposed electrode group 4
are disposed in a pattern as shown in the figure by etching or other means on a surface dielectric layer made of polyester or polymide or the like with a thickness of about 100 μm. Further, the buried electrode groups 5 and 6 are arranged on the insulating support layer 3 in a pattern as shown in the figure, and the surface dielectric layer 1
An internal dielectric layer 2 made of silicone rubber and having a thickness of approximately 100 μm is provided between the insulating support layer 3 and the insulating support layer 3 for the purpose of bonding them together.

Further, the exposed electrode group 4 is placed on the surface dielectric layer 1 at a location where the exposed electrode group 4 and the buried electrode group 5 face each other.
A band-shaped insulator layer 14 is provided to cover the end portion of the insulator. As this band-shaped insulating layer 14, a silicone rubber layer having a thickness of about 0.3 to 0.5 mm and a width of about 5 mm is suitable.

When a three-phase alternating voltage is applied to the electrode terminals 10, 11, and 12 of the electric field curtain sheet configured as described above, the electrode groups 4, 5, and 6 appear on the surface dielectric layer 1.
An unequal electric field array is formed that moves perpendicular to the
Charged particles present on the surface dielectric layer 1 can be transported in said direction. Note that this operation has been clarified in the patent application filed by the present inventors, so a detailed explanation will be omitted.

By the way, in the electric field curtain sheet of this embodiment, when the gap between adjacent electrodes is about 3 mm, the interphase applied voltage is generally required to be about 3 to 6 KV (RMS). For this reason, sufficient attention must be paid to dielectric strength.

In particular, it is necessary to increase the dielectric strength at point (2) mentioned in the explanation of the prior art. In this example,
As described above, since the strip-shaped insulating layer 14 covers the end portion of the exposed electrode group 4, the following effects can be obtained.

(1) Generation of corona discharge from the end of exposed electrode group 4 is stopped, and ionization of air is stopped.

(2) The impedance between the end of exposed electrode group 4 and the end of buried electrode group 5 becomes large.

Therefore, it becomes possible to strengthen the dielectric strength between the end portion of the exposed electrode group 4 and the end portion of the buried electrode group 5.

In the above embodiments, the present invention has been explained using a one-phase exposed type electric field curtain sheet as an example, but the present invention is not limited thereto, and can of course be applied to an all-phase buried type electric field curtain sheet.

As described above, according to the present invention, it is possible to prevent corona discharge from occurring from the end of the exposed electrode group of the electric field curtain sheet, and also to prevent the occurrence of corona discharge from the end of the exposed electrode group and the end of the buried electrode group. Since the impedance between the electric field curtain sheets can be increased, the life of the electric field curtain sheet can be extended, and safety can be improved.

[Brief explanation of drawings]

Figure 1 is a plan view of a conventional electric field curtain sheet.
Figure 2 is a sectional view taken along the line X-X in Figure 1, and Figure 3 is a cross-sectional view of Figure 1.
4 is an enlarged detailed view of the vicinity of the end of the electrode in FIG. 1, FIG. 5 is an electrical equivalent circuit diagram between the exposed electrode and the buried electrode, and FIG. FIG. 7 is a plan view of an electric field curtain sheet according to an embodiment, and a sectional view taken along the Z-Z line in FIG. 6 is shown. 1...Surface dielectric layer, 2...Inner dielectric layer, 3...
Insulating support layer, 4... Exposed electrode group, 5, 6... Buried electrode group, 7, 8, 9... Distribution electrode, 10, 11, 1
2... Electrode terminal, 13... Insulator layer, 14... Band-shaped insulator layer.

Claims (1)

[Claims] 1. An electric field curtain device in the form of a sheet or a panel, characterized in that the surface of the electric field curtain device located at the end of the electric field curtain electrode is covered with an insulator.