JPH04370699A - Cylindrical plasma generating device - Google Patents

Abstract

PURPOSE:To generate plasma in stable expansion under the atmospheric pressure. CONSTITUTION:A thin wire is wound at a certain specified pitch on an insulative rod 3 arranged in a cylindrical pos. electrode 1 in coaxial arrangement to form a spiral neg. electrode 2, and a barrier pipe 4 made from a heat resistant insulative material is installed inside of the pos. electrode 1, and thereby a stable plasma is produced being expansive from the spiral neg. electrode 2 toward the cylindrical pos. electrode 1, continuous spirally, and with no gap when viewed in the axial direction.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a plasma generator that generates discharge plasma in the atmosphere by applying a high voltage between electrodes. Regarding equipment.

0002

2. Description of the Related Art Conventionally, there are electrode devices for generating discharge plasma that use various electrodes, such as parallel plate type electrodes, Rogowski type electrodes, and needle-to-plate type electrodes.

0003

[Problem to be solved by the invention] However, most of these are plasma generating electrodes that are used at a pressure lower than atmospheric pressure, and are capable of stably generating and sustaining corona discharge or glow discharge that spreads at atmospheric pressure. There are few electrode structures like this. In particular, there are few electrodes that can generate stable and widespread corona discharge or glow discharge in ozone generation or exhaust gas treatment at atmospheric pressure, and most electrodes have small electrode spacing or use creeping discharge, etc. is narrow.

[0004] Therefore, the flow rate of gas that can generate ozone or exhaust gas is limited, making it unsuitable for processing large flow rates. Further, even if parallel plate type or Rogowski type electrodes used in low-pressure glow discharge are used at atmospheric pressure, arc discharge is likely to occur, and it is difficult to generate a wide plasma.

The present invention has been made in view of these conventional problems, and its purpose is to create a cylindrical plasma generator capable of generating a stable and expansive plasma at atmospheric pressure. The goal is to provide equipment.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the cylindrical plasma generator of the present invention includes a cylindrical positive electrode and an insulating rod disposed coaxially within the cylindrical positive electrode. It consists of a spiral negative electrode wound at a predetermined pitch and a barrier tube made of a heat-resistant insulating material placed inside a cylindrical positive electrode.

[0007]

[Operation] When a high voltage is applied between the cylindrical positive electrode and the spiral negative electrode, the spiral electrode is made of thin wire, so
Even if the electric field is distorted and the high voltage is relatively low, plasma is generated that continues in a wide spiral shape with a wide discharge region that spreads toward the cylindrical positive electrode and has no gaps when viewed in the axial direction. This plasma is stabilized by a barrier tube provided inside the cylindrical positive electrode. Therefore, within this barrier tube, for example,
If air or oxygen for ozone generation or exhaust gas for exhaust gas treatment is flown, all of these gases can be exposed to plasma, so ozone generation or exhaust gas treatment using plasma can be performed efficiently. be able to.

[0008]

Embodiments An embodiment of the present invention will be described with reference to the drawings.

In FIGS. 1 and 2, 1 is a cylindrical positive electrode, and 2 is a cylindrical positive electrode.
4 is a spiral negative electrode formed by winding a thin wire at a predetermined relatively large pitch around a heat-resistant insulating rod 3 arranged coaxially within the cylindrical positive electrode 1; 4 is a heat-resistant insulating rod 3 provided inside the cylindrical positive electrode 1 This is a barrier tube made of a conductive insulating tube. In the barrier pipe 4, for example, air or oxygen to be ozonated or exhaust gas to be treated flows.

Direct current is applied to the cylinder between electrode 1 and the spiral negative electrode.
When a high voltage is applied from either an alternating current or pulsed high voltage source, the spiral negative electrode 2 moves toward the cylindrical positive electrode 1 as shown in Figure 2.
Plasma a is distributed and continuous in a spiral shape as shown in
occurs. This plasma a becomes more stable because of the presence of the barrier tube 4.

Barrier tube 4 in which this plasma a is generated
When, for example, exhaust gas b flows into the exhaust gas from one end, nitrogen oxides and sulfur oxides in the exhaust gas b are decomposed by plasma, and processing gas c is discharged from the other end.

[0012] As the cylindrical positive electrode, it is possible to use a metal cut into a cylindrical shape, a metal plate or a metal plate mesh bent into a cylindrical shape, or a cylindrical film in which metal is deposited directly on the outside of the barrier tube. .

[0013]

[Effects of the Invention] Since the present invention is constructed as described above, it produces the following effects.

(1) Since a spiral electrode is provided within the cylindrical positive electrode, plasma is generated without any gaps.

(2) Since the barrier tube is placed inside the cylindrical positive electrode, plasma is stabilized and deterioration of the cylindrical positive electrode is prevented.

(3) Since the spiral negative electrode is a thin wire, the electric field is distorted and plasma can be generated even when the applied voltage is relatively low, so the diameter of the cylindrical positive electrode can be increased.
A wide plasma can be generated.

[Brief explanation of drawings]

FIG. 1 is a partially cross-sectional perspective view of an electrode portion of a cylindrical plasma generator according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of an electrode section showing plasma distribution.

[Explanation of symbols]

1...Cylindrical positive electrode, 2...Spiral negative electrode, 3...Insulating rod,
4...Barrier tube.

Claims (1)

[Claims] Claim 1: A cylindrical positive electrode, a spiral negative electrode formed by winding a thin wire at a predetermined pitch around an insulating rod coaxially arranged inside the cylindrical positive electrode, and a heat-resistant electrode arranged inside the cylindrical positive electrode. A cylindrical plasma generator characterized by consisting of a barrier tube made of insulating material.