JPH0696718A - Electrode for atmospheric pressure glow-discharge plasma - Google Patents

Abstract

PURPOSE:To accomplish the stabilization of glow discharge by arranging a number of metal-made pipes each having a ceramic thermal spraying layer on the surface thereof in parallel to each other at small intervals to easily replace air between electrodes with plasma generating gas. CONSTITUTION:A stainless steel pipe with the diameter of about 10mm and the length of about 1150mm is bent at a right angle in the position of 50mm from the end thereof to form a part of an electrode 2. About 60 similar pieces are fitted to a metal frame 3 at an interval of 2 to 5mm to form an electrode. After the pipes are so lightly pressed as to form the bottom of the pipes in a uniform plane, ceramic thermal spray is applied to the whole surface of the pipes to make a dielectric coating film to be an upper electrode. For a lower electrode, a glass plate of 1mm thick is placed for a dielectric material on a brass plate of 10mm thick with an area of 1m<2>. The upper and lower electrodes are placed at an interval of 10mm in a plasma reaction vessel, and the mixed gas of Ar and He is injected thereinto and a voltage of 3000 volts at 3000Hz is applied to make decision on the complete replacement with air at the time when glow discharge is brought about.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode for an atmospheric pressure glow discharge plasma used to generate an atmospheric pressure plasma, and more particularly, to easily replace the air between the electrodes with a gas for generating a plasma, which is stable. The present invention relates to an atmospheric pressure glow discharge plasma electrode that performs glow discharge.

[0002]

2. Description of the Related Art Atmospheric pressure plasma is a mixture of inert gases such as helium and helium argon, or a gas in which a small amount of ketone is added to argon, and a high frequency voltage is applied between the upper and lower electrodes to generate a glow discharge. It is obtained by the method of modifying the surface of the substance located between them, and a major feature is that the equipment cost can be reduced because different vacuum plasma devices are used in the atmosphere.

Conventionally, an electrode used to obtain plasma is a plate-shaped metal electrode, and a dielectric sheet larger than the electrode is attached to the surface of the plate-shaped metal electrode, which is placed in a reaction vessel with a small gap. . The metal used for the electrode is made of a plate of brass, stainless steel, aluminum or the like, and Kapton, Teflon, glass, mica, or ceramic is used as the dielectric sheet.

Then, this electrode is installed in a reaction vessel,
The air in the container is replaced with an inert gas for generating an atmospheric pressure plasma as described above, and generally between 500 and
When a high frequency of 10000 Hz is applied at a high voltage, a purple glow discharge occurs. Plasma is excited in the gap of the glow discharge, and the plastics, fibers, and the like placed between them are made hydrophilic, and the contact angle of the surface can be reduced, that is, wetting can be made extremely good.

Such an atmospheric pressure plasma electrode is not a problem when it is used in a small scale such as in a laboratory, but when the area of the electrode is industrially 1 m ² or more, the air in the gap between the electrodes becomes easy. Stable, not completely replaced with
There is a problem that it takes a long time to generate a discharge.

[0006]

The present inventor has completed the present invention as a result of various studies to solve the above-mentioned drawbacks, and an object of the present invention is to generate air for generating plasma between the electrodes. It is an object of the present invention to provide an electrode for atmospheric pressure glow discharge plasma which can be replaced easily and can perform stable glow discharge.

[0007]

SUMMARY OF THE INVENTION The gist of the present invention is to provide an electrode for an atmospheric pressure glow discharge plasma comprising a large number of metal pipes having a ceramic sprayed layer on the surface thereof and arranged in parallel at a small interval. Is. That is, in the present invention, a large number of pipes or circular rods are used as electrode plates, and a large number of these are arranged in parallel in parallel with each other at a small interval. Further, the surface of the electrode is subjected to ceramic spraying so that air between both electrodes is piped. Or, since it is discharged from the gap between the circular rods, the replacement with the inert gas for plasma generation can be done very quickly, and further,
It is possible to generate a strong glow discharge.

The present invention will be described in more detail. The electrode pipe or round bar used in the present invention has a diameter of about 5 to 15 mm, preferably about 10 mm, and its length varies depending on the size of the reaction vessel, but it is about 50 to 90, preferably 70 to It is about 80. The tip of this pipe or round bar may be bent. The gap between the pipes or round bars is not particularly specified, and is usually 1 to 10 mm, preferably 2 to 5
However, if the frame to be mounted has a size of 1 m ² , about 7,80 pipes with a diameter of 10 mm can be mounted. The surface of these pipes or round bars is welded with ceramic by a conventional method.

When using the electrode of the present invention, both electrodes may use the electrode of the present invention, or
The electrode of the present invention may be used for only one of the electrodes, and the other may be a plate electrode to which Kapton, glass, or ceramic as a dielectric is laminated or ceramic is sprayed. Air in the container is discharged from one side and an inert gas for plasma generation flows into the reaction container from the other side. The inflow rate of the inert gas is not different from that when using a plate-shaped electrode,
In the case of the present invention, the inert gas freely flows between the electrodes from the gap between the pipes for the electrodes and replaces the air very quickly. When the replacement is completed or not, a voltage of 3000 V between the electrodes and about 3000 V is applied, and a purple glow discharge occurs when the replacement is complete. When the air component remains, glow discharge does not occur or higher voltage is required.

When a high frequency high voltage of 3000 Hz and 3000 V is applied between both electrodes in the state where the glow discharge occurs, a strong glow discharge occurs from the tip of the pipe, and a strong discharge occurs through the slit of the container. When the plastic film to be treated is run, its surface is uniformly plasma-treated, and a hydrophilic or hydrophobic surface can be freely formed.

In the electrode using such a pipe or round bar, it is necessary to move the object to be processed in a direction perpendicular to the pipe, and in parallel, the object to be processed becomes striped and uneven. In the case of an electrode using a pipe, cooling water may be passed through the pipe when cooling is required, and heating can be achieved by passing a heat medium when heating is required. In the case of the conventional plate electrode, a copper tube has to be stretched around the electrode plate for cooling and heating, and in comparison with this, when the electrode of the present invention is used, the apparatus is much simpler.

The details will be described below with reference to the drawings. Figure 1
FIG. 2 is a side view and a plan view of an electrode according to the present invention, and FIG. 2 is an enlarged explanatory view of the electrode. Further, FIG. 3 is a view showing a state in which the electrode is attached to the reaction container. A stainless pipe 2 having a diameter of 10 mm as shown in FIG. 2 is bent to have rounded corners and attached to a mounting frame 3 made of a metal frame to form an electrode 1 as shown in FIG.

The electrode 1 is attached to the reaction container 4 as shown in FIG. The gap between the stainless steel pipes is 2 to 3 mm, and the entire surface of the pipes is coated with the ceramic by performing thermal spraying of the ceramics. The reaction container is provided with a gas outlet 4 and a gas inlet 5. Air inside the container is discharged from one gas outlet 6 and an inert gas for plasma generation is introduced from the other gas inlet 5.

For example, 40 parts by volume of helium from the gas inlet,
When a mixed gas of 70 parts by volume of argon is flown into a reaction vessel having an internal volume of 15 liters at a flow rate of 6 liters per minute, the mixed gas freely enters through the gap between the pipes as shown by the arrow in FIG. Complete. Then, the object to be processed 7
Is introduced from one side of the reaction vessel 4, passes through between the electrodes, and is taken out from the other side for plasma treatment. Next, the present invention will be specifically described with reference to examples.

[0015]

[Examples and Comparative Examples]

Example 1 A stainless tube having a diameter of 10 mm and a length of 1150 mm is bent at a right angle at a distance of 50 cm from each end to form a part of the electrode 2 shown in FIG. Sixty of the same ones were made and attached to a metal frame at 5 mm intervals to form electrodes. The area of the electrode is 1 square meter. Since the stainless steel pipe used for the electrode is slightly deformed by the heat of welding, it was lightly pressed so that the lower surface of the pipe has a uniform flat surface. Ceramics were sprayed on the entire surface of the tube to form a dielectric film, which was used as the upper electrode. The thickness of the dielectric film was about 0.8 mm. The lower electrode is 10 mm thick and 1 m ²
A 1 mm thick glass plate was placed as a dielectric on the brass plate. The upper and lower electrodes were installed in a hard aluminum plasma reaction vessel with an internal volume of 400 liters, and the distance between the upper and lower electrodes was 10 m.
m. A mixed gas of argon and helium was injected into this at a rate of 40 liters per minute, and the time until the air was completely replaced was measured. This end point is 3000Hz, 3
It was determined by applying a voltage of 000 V and causing glow discharge. As a result, a glow discharge occurred 19 minutes after the gas was injected, and the replacement was completed. Further, the glow discharge was extremely stable and an output of 500 W or more was obtained.

Next, as a comparative example, the upper electrode has a thickness of 10 mm,
A brass plate of 1 square meter was used, the distance between the upper and lower electrodes was set to 10 mm as in the example, and a polyimide film having a thickness of 100 μm was laminated as the dielectric material, and the same replacement was performed. The lower electrode is exactly the same as in the embodiment. In this case, it took 40 minutes for the glow discharge to occur, and the output was 300W. From this example, it was found that the effect of the electrode according to the present invention was extremely large.
Furthermore, the weight of the electrode is about 80 for a brass plate electrode with a thickness of 10 mm.
In contrast to Kg, the electrode of the present invention has the same area of 35 Kg.
It is light and easy to hold.

[0017]

As described above, according to the present invention, a large number of metal pipes having a ceramic sprayed layer on the surface are arranged at small intervals as electrodes for the atmospheric pressure glow discharge plasma. Air can be easily replaced with an inert gas for plasma generation, and as a result, stable glow discharge can be generated early and,
Cooling or heating of the electrode can be easily achieved by introducing cooling water or a heat medium into the pipe, and therefore, the device can be simplified.

[Brief description of drawings]

FIG. 1 is a side view and a plan view of an electrode according to the present invention.

FIG. 2 is a perspective view of an electrode according to the present invention.

FIG. 3 is a side view of a reaction container having an electrode attached.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrode for plasma of this invention 2 Stainless steel pipe 3 Mounting frame 4 Reaction container 5 Gas outlet 6 Gas inlet 7 Object to be treated

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[Procedure amendment]

[Submission date] November 27, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 1

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

[0007]

SUMMARY OF THE INVENTION The gist of the present invention is that an atmospheric pressure glow discharge plasma is formed by arranging a large number of metal pipes having a ceramic layer or a glass layer on their surfaces in parallel with each other at a small interval. It is an electrode for. That is, in the present invention, a large number of pipes or circular rods are used as electrode plates, and a large number of these are arranged in parallel in parallel with each other at a small interval. Further, the surface of the electrode is subjected to ceramic spraying so that air between both electrodes is piped. Alternatively, since the gas is discharged from the gap between the circular rods, the replacement with the inert gas for plasma generation can be performed very quickly, and a strong glow discharge can be generated.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

The present invention will be described in more detail . The electrode pipe or round bar used in the present invention has a diameter of about 5 to 15 mm, preferably about 10 mm, and its length varies depending on the size of the reaction vessel, but is about 5 mm.
The number is 0 to 90, preferably 70 to 80. The tip of this pipe or round bar may be bent. The gap between the pipes or round bars is not particularly specified, and is usually 1 to 10 mm, preferably 2 to 5
However, if the frame to be mounted has a size of 1 m ² , about 7,80 pipes with a diameter of 10 mm can be mounted. The surface of these pipes or round bars is provided with a ceramic layer or glass layer by a conventional method .

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

When a high frequency high voltage of 3000 Hz and 3000 V is applied between both electrodes in the state where the glow discharge occurs, a strong glow discharge occurs between the both electrodes, and a strong discharge occurs through the slit of the container. When the plastic film of the object is run, its surface is uniformly plasma-treated, and a hydrophilic or hydrophobic surface can be freely formed.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

The electrode 1 is attached to the reaction container 4 as shown in FIG. The gap between the stainless steel pipes is 2 to 3 mm, and the entire surface of the pipes is coated with the ceramic by performing thermal spraying of the ceramics. The reaction container is provided with a gas outlet 6 and a gas inlet 5. Air inside the container is discharged from one gas outlet 6 and an inert gas for plasma generation is introduced from the other gas inlet 5.

[Procedure correction 6]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

[0015]

Make some of the Examples and Comparative Examples] Example 1 10mm diameter length respectively from the end of the stainless steel tube of 1150 mm 50 m electrodes are shown at right angles bent 2 at the m 2. Sixty of the same ones were made and attached to a metal frame at 5 mm intervals to form electrodes. The area of the electrode is 1 square meter. Since the stainless steel pipe used for the electrode is slightly deformed by the heat of welding, it was lightly pressed so that the lower surface of the pipe has a uniform flat surface. Ceramics were sprayed on the entire surface of the tube to form a dielectric film, which was used as the upper electrode. The thickness of the dielectric film was about 0.8 mm. The lower electrode is 10 mm thick and 1 m ²
A 1 mm thick glass plate was placed as a dielectric on the brass plate. The upper and lower electrodes were installed in a hard aluminum plasma reaction vessel with an internal volume of 400 liters, and the distance between the upper and lower electrodes was 10 m.
m. A mixed gas of argon and helium was injected into this at a rate of 40 liters per minute, and the time until the air was completely replaced was measured. This end point is 3000Hz, 3
It was determined by applying a voltage of 000 V and causing glow discharge. As a result, a glow discharge occurred 19 minutes after the gas was injected, and the replacement was completed. Further, the glow discharge was extremely stable and an output of 500 W or more was obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Sachiko Okazaki 2-20-11 Takaido, Suginami-ku, Tokyo (72) Inventor Masuhiro Ogoma 843-15 Shimoshinkura, Wako-shi, Saitama

Claims (1)

[Claims] 1. An electrode for atmospheric pressure glow discharge plasma, comprising a large number of metal pipes having a ceramic sprayed layer on the surface thereof and arranged in parallel at a small interval.