JP2007250284A - Plasma electrode - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma electrode capable of efficiently generating plasma with reduced power consumption, improving a contact circulative property between fluid and the plasma, and facilitating the utilization of plasma for a consumer use or the like. <P>SOLUTION: A dielectric film is formed at least on one surface of the opposing plate faces of metal plates firmly fitted to each other with ruggednesses formed of a height difference within a range of 5 μm or more and 50 μm or less and an arbitrary flat-pattern shape, whereby, microplasma discharge is generated between both the metal plates. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

Detailed Description of the Invention

  The present invention relates to an electrode configuration that causes plasma discharge for indoor air purification, ozone generation, sterilization / sterilization, exhaust gas purification, water purification, and sterilization in water.

Technical background

  From the industrial field to the consumer field, research and development of discharge electrodes for generating plasmas that are expected to be applied in various fields are being promoted in various fields.

In particular, in a field of use where ozone is generated from oxygen in the atmosphere by plasma to purify the air, various discharge electrodes have been developed to adapt to consumer demand (Patent Documents 1 and 2). reference).
JP-A-63-190702 JP 2005-21319 A

  However, in the prior art, the flow between the discharge electrodes is about several millimeters because the fluid such as air is in contact with the plasma to ensure sufficient flowability, so that the applied voltage for generating the plasma is therefore Needs to be several kV or more, and power consumption is large.

  In addition, a technology (microplasma technology) has been developed to generate a silent discharge or creeping discharge with a gap between the electrodes of the order of μm, thereby realizing efficient plasma generation at a low voltage. In order to reduce the size, a very large pressure differential loss occurs when a fluid such as air is circulated, and a special press-fitting means or the like is required for that purpose. In addition, since the electrode is embedded in the ceramic substrate, there are problems such as heat generated during long-term operation, ozone generation efficiency is reduced, and discharge cannot be sustained due to base generation due to harmful gas on the surface electrode. There has been a problem.

  In the conventional technology, it is difficult to achieve both the contact property between the fluid and the plasma and the reduction in energy consumption. In the microplasma technology, the mechanical configuration of plasma generation requires the combination of fine members. This is a major limitation in plasma applications for consumer use.

In view of the problems of the conventional invention, the inventor of the present application can reduce power consumption by a gap between electrodes on the order of μm, improve fluid flowability, and use a mechanical structure with ease and durability. It came to invent the plasma electrode with. Providing indoor air cleaning with a microplasma filter that has a cooling structure that does not affect even long-time operation and suppresses the sustained decrease in discharge due to contamination of the electrode surface. Objective.
The invention of claim 1 of the present application is a plasma electrode composed of a pair of metal plates in which one or more flow ports for allowing fluid to flow in a direction perpendicular to the plate surface are formed, the plate surfaces facing each other. A dielectric film is formed on at least one surface of the metal plate, and the surface of the dielectric film is formed with concavities and convexities having a height difference in the range of 5 μm or more and 50 μm or less and an arbitrary planar pattern shape, and is opposed to a metal plate These plate surfaces are plasma electrodes characterized in that they are surface-attached to each other and a voltage is applied between both metal plates to cause plasma discharge.

  In the invention of claim 2, the plasma electrode on which the dielectric film is formed has a range of 5 μm or more and 50 μm or less on the surface of the dielectric film previously formed on the surface of the metal plate by chemical or mechanical removal means. The plasma electrode according to claim 1, wherein the unevenness having a height difference of 2 and an arbitrary planar pattern shape is formed.

  According to the invention of claim 3 of the present application, the plasma electrode on which the dielectric film is formed has a height difference in the range of 55 μm or more and 550 μm or less and an arbitrary planar pattern shape on the surface of the metal plate in advance by chemical or mechanical removal means. 3. The plasma electrode according to claim 1 or 2, wherein a concavo-convex shape is formed, and then a dielectric film is formed on the surface of the metal plate.

  The invention according to claim 4 is the plasma electrode according to any one of claims 1 to 3, wherein the dielectric film is made of a material mainly composed of barium titanate and alumina.

  A fifth aspect of the present invention is the plasma electrode according to any one of the first to fourth aspects, wherein the dielectric film formed on the surface of the metal plate has a thickness of 50 μm or more and 500 μm or less. .

  The invention according to claim 6 of the present application is characterized in that a resin film made of tetrafluoroethylene resin or silicone resin is further formed on the surface of the dielectric film. Electrode.

  In the invention of claim 7 of the present application, the flow for flowing the fluid is such that the horizontal or vertical diameter on the surface of the plasma electrode on which the dielectric film is formed is 100 μm or more and 10 mm or less, preferably 200 μm or more and 400 μm or less. The plasma electrode according to any one of claims 1 to 6, characterized in that:

  According to the invention of claim 8 of the present application, the area ratio of the opening of the flow port on the plasma electrode surface on which the dielectric film is formed is 2% to 60%, preferably 20% to 40% of the outer peripheral area of the electrode surface. The plasma electrode according to any one of claims 1 to 7, wherein one or more flow ports are formed as described above.

  The invention according to claim 9 is the plasma electrode according to any one of claims 1 to 8, wherein a dielectric film or a resin film is further formed on the back surface of the opposing plate surface.

  As described above, the plasma electrode of the present invention can generate plasma efficiently by reducing power consumption, and can improve the contact flow between fluid and plasma. Can be facilitated. In addition, the plasma electrodes according to claims 1 to 9 are arranged in pairs, and a plurality of plasma electrodes are arranged so that fluid passes through the flow path to constitute one plasma electrode as a whole. Thus, it is possible to improve the efficiency of cleaning the indoor air and improve the ozone generation concentration. Furthermore, in such an application, it is also possible to adopt a configuration in which the electrodes are closely opposed to each other by a configuration in which odd-numbered and even-numbered plasma electrodes are electrically connected and supplied with power.

Hereinafter, embodiments of the present invention will be described.
FIG. 1 schematically shows a cross-sectional view and a plan view of a plasma electrode of the present invention. The shape of the opening can be any shape such as a circle, a triangle, a rectangle, or a polygon, and other design shapes such as a star shape can also be used.

  As shown in FIG. 1, a plasma electrode formed by opposing a pair of metal plates has a dielectric film formed on at least one surface, and the surface of the dielectric film has a height difference of 5 μm or more and 50 μm or less and an arbitrary plane pattern. Concavities and convexities having a shape are formed, and the multiple surfaces of the opposing metal plates are surface-attached to each other.

  In addition, as shown in FIG. 2, the plasma electrode has irregularities formed in an arbitrary pattern on the dielectric film.

  As shown in FIG. 3, it is recognized that ozone is generated at a low voltage when an arbitrary height difference is low.

  As shown in FIG. 4, the optimum value of the dielectric coating film thickness is recognized. In the case of this example, it is 400 μm.

  As shown in FIG. 5, it is recognized that a higher ozone concentration can be obtained even when the relative humidity is higher than the creeping discharge.

As shown in FIG. 6, it is recognized that formaldehyde is removed with low power consumption.

Diagram showing plasma electrode Photo created on the surface with an arbitrary height difference using a dielectric film Characteristic diagram showing the relationship between ozone generation concentration and discharge voltage by changing the distance between electrodes Diagram showing the relationship between ozone generation concentration and discharge voltage depending on dielectric film thickness Diagram showing the relationship between relative humidity and generated ozone concentration Diagram showing the removal characteristics of formaldehyde

Claims (9)

A plasma electrode in which a metal plate having one or more flow ports formed is disposed opposite to each other, and a dielectric film is formed on at least one surface of the opposing plate surfaces of the metal plate. The surface of the metal plate is uneven with an elevation difference of 5 μm or more and 50 μm or less and an arbitrary plane pattern shape, and the plate surfaces of the opposing metal plates are fixed to each other, or are 5 μm or more. A plasma electrode, characterized in that it is fixed to maintain an interval of 100 μm or less, and a power is applied to cause plasma discharge between both metal plates.   The plasma electrode on which the dielectric film is formed is formed on the surface of the dielectric film previously formed on the surface of the metal plate by a chemical or mechanical removal means, with a height difference in the range of 5 μm to 50 μm and an arbitrary plane pattern. The plasma electrode according to claim 1, wherein the plasma electrode is formed with irregularities having a shape.   The plasma electrode on which the dielectric film is formed is formed in advance on the surface of the metal plate by means of chemical or mechanical removal means, with irregularities having a height difference in the range of 55 μm to 550 μm and an arbitrary plane pattern shape. 3. The plasma electrode according to claim 1, wherein a dielectric film is formed on the surface of the metal plate.   4. The plasma electrode according to claim 1, wherein the dielectric film is made of a material mainly composed of barium titanate and alumina.   5. The plasma electrode according to claim 1, wherein the dielectric film formed on the surface of the metal plate has a thickness of 50 μm or more and 500 μm or less.   6. The plasma electrode according to claim 1, wherein a resin film made of tetrafluoroethylene resin or silicone resin is further formed on the surface of the dielectric film.   The flow for flowing the fluid is characterized in that the diameter in the horizontal direction or the vertical direction on the surface of the plasma electrode on which the dielectric film is formed is 100 μm or more and 10 mm or less, preferably 200 μm or more and 400 μm or less. The plasma electrode according to any one of claims 1 to 6.   One or more flow ports so that the opening area ratio of the flow port on the plasma electrode surface on which the dielectric film is formed is 2% or more and 60% or less, preferably 20% or more and 40% or less of the outer peripheral area of the electrode surface. The plasma electrode according to claim 1, wherein the plasma electrode is formed.   9. The plasma electrode according to claim 1, wherein a dielectric film or a resin film is further formed on the back surface of the opposing plate surface.