JPH01275403A - ozone generator - Google Patents

Abstract

PURPOSE:To utilize both creeping discharge and silent discharge, to remove effecting the discharge heat, to prevent the fatigue of an electrode, and to stabilize the O3 generation efficiency by superposing a counter electrode on both front and rear surfaces of one electrode of specified structure through a ceramic sheet. CONSTITUTION:Many flat parts 2, 2,... are arranged in parallel on the same plane on the front and rear outermost surfaces of a metallic flat sheet 1, the region of the flat sheet 1 other than the flat part 2 is formed with the recesses 3, 3,... having a depth successively increasing in the direction separating from the flat part 2, the recess 3 is allowed to extend from one to other sides of the flat sheet 1, and a small hole 4 communicating with the recess 3 on the front side and the recess 3 on the rear side is bored through the flat sheet 1 to constitute one thin sheet-shaped electrode 10. A ceramic sheet 11 is allowed to abut on both front and rear surfaces of the electrode 10 at the flat part 2, a conductive paint, for example, is applied on the outer surface of the ceramic sheet 11, or a thin metallic sheet is used to superpose the couter electrode 12 on the electrode 10, and a gaseous raw material is passed through the recess 3 from one side of the electrode 10 to the other side.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application 1 The present invention relates to an ozone generator that converts oxygen into ozone by electric discharge.

``Prior art'' The most common type of ozone generator in the past is called the silent discharge type, in which one electrode to which high-voltage, high-frequency power is applied is placed with a predetermined gap between it and a dielectric material such as glass or ceramics. and a counter electrode on the ground side is arranged on the opposite side of the one side electrode of the dielectric body, and a strong electric field is generated in the gap between the one side electrode and the dielectric body, A source gas such as oxygen or air is allowed to pass through this discharge field.

Also, recently, one side electrode pattern in the form of metal foil is laminated on one side of a dielectric, and the other side electrode is laminated on the other side (sometimes the other side +'Tt4,4 is buried in the dielectric). A creeping discharge type ozone generator has been proposed in which a creeping discharge is generated on a surface where electrode patterns are laminated, and a raw material gas is brought into contact with this creeping discharge field.The problems to be solved by the present invention In the ozone generator, there remain problems such as how to efficiently remove the heat generated by discharge, and how to efficiently bring the raw material gas into contact with the discharge field.

It is known that ozone generation in a high-temperature discharge field is caused by the generated ozone being decomposed by heating, which reduces the ozone generation efficiency, and also generates harmful NOx when air is used as the raw material. There is. Although the reason for the generation of NOx is not necessarily clear, the main cause is thought to be that oxygen activated when ozone decomposes combines with nitrogen.

That is, in the conventional ozone generator described above,
The former silent discharge type has the disadvantage that it is necessary to cool the outer surface of one electrode and the outer surface of the other electrode while electrically insulating each other, making the cooling device complicated. Specifically, if cooling water is to be circulated for cooling, the cooling water system of one electrode and the cooling water system of the other electrode must be separated without being electrically connected.

In addition, in the latter creeping discharge type, since the surface contact between one electrode, the dielectric, and the other electrode makes it possible to efficiently cool the creeping discharge field by cooling the outer surface of the other electrode, If the upper part of the creeping discharge field is appropriately covered with an insulating material and the raw material gas is allowed to pass between this insulating material and the dielectric material, electrical continuity can be established between the outer surface of the other electrode and the outer surface of this insulating material. However, since the creeping discharge type has a thin electrode pattern and creeping discharge layer on one side, the electrodes on the other side may be worn out or damaged due to discharge, resulting in poor durability. It has the disadvantage that the raw material gas passing through it comes into surface contact with the creeping discharge field, making it difficult for the entire amount of the raw material gas to come into contact with the discharge field, resulting in a low ozone generation efficiency.

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks, the present invention provides an ozone generator that can efficiently cool several electrodes and the discharge field by a simple means, and can also ensure that the entire amount of raw material gas passes through the discharge field. The purpose is to

"Means for Solving the Problems" In line with the above-mentioned object, the structure of the present invention, which is summarized in the above-mentioned claims, has the same structure on both the front and back outermost surfaces of the metal flat plate 1 in order to solve the above-mentioned problems. A large number of flat parts 2, 2, 2, etc. are arranged side by side on a plane, and the parts of the flat metal plate 1 other than each flat part 2 are gradually deepened in the direction away from the flat part 2. The recesses 3, 3, 3, . A technique in which one side electrode 10 is formed by opening a small hole 4 communicating with the recess 3 on the back surface side, and a mating mold 8i12 is superimposed on both the front and back surfaces of the one side electrode 10 via ceramic plates 11, respectively. The measures taken were as follows.

r Effect J Therefore, in the ozone generator of the present invention, when a high voltage, high frequency power source is applied between one electrode 10 and the other electrode 12, 12, a discharge field is formed within each recess 3.

In the discharge field within each of the recesses 3, creeping discharge occurs near the outer periphery of the flat portion 2 because the flat portion 2 overlaps the ceramic plate 11. Then, since the gap gradually becomes larger at a portion away from the outer periphery of the flat portion 2, a silent discharge occurs. This combination of creeping discharge and silent discharge has the effect that the creeping discharge induces silent discharge and prevents rapid changes in current value such as peak current.

One side electrode 10 is placed in the recess 3 in this discharge state.
When the raw material gas is passed from one side to the other side, the raw material gas passes through the discharge field generated in the recess 3 and is ozonized.

In addition, the small holes 4 allow the raw material gas to freely move to the front and back sides of the metal flat plate 1, allowing it to flow through the flow path. 31 becomes rough and even forms eddy currents in some parts, increasing the probability of contact with the discharge field and the contact time.Furthermore, it has the effect of averaging the flow rate on the front and back sides of the metal flat plate 1 and preventing fluctuations in ozonization efficiency. , the other electrode 1 is connected to the front and back surfaces of the one side electrode 10 via ceramic plates 11, respectively.
2 are superposed, the inner surface of the ceramic plate 11 contacts the flat surface 2 of the one side electrode 10, and the inner surface of the other electrode 12 contacts the outer surface of the ceramic plate 11. The other electrode 12.12 maintains high thermal conductivity without passing through a highly insulating air layer.
connected to the outer surface of the two-phase square electrode 12.12
are electrically the same polarity.

"Example" Next, embodiments of the present invention will be described based on the accompanying drawings.

In the figure, 1 is a metal flat plate that constitutes one side electrode 10.

The metal flat plate 1 has a large number of flat parts 2, 2, 2, . There are a large number of recesses 3, 3.
3..., each of the recesses 3 is continuous from at least one side of the metal flat plate 1 to the other side, and furthermore, the metal flat plate 1 has a recess 3 on the back side than the recess 3 on the front side. A small hole 4 is opened to communicate with the electrode 10 on one side.

The flat portion 2, recessed portion 3, and small hole 4 may be formed by a conventionally known manufacturing method such as press molding, excavation molding, or etching molding. The area ratio between the flat part 2 and the recessed part 3 may be selected as appropriate, but it is preferable that the two are arranged alternately and uniformly over the entire surface. Ensure contact surfaces and position them on the same plane with mechanical precision (one side electrode 10 and the other side electrode 1 described later).
2), and the contact surface contacts the ceramic plate 11 with a predetermined area to maintain good heat conduction. By uniformly receiving the inner surface, the mechanical strength of the ceramic plate 11 is supplemented.

In addition, the surface recess 3 secures a discharge space and a flow path for raw material gas, and in the embodiments shown in FIGS. 1 and 3,
As shown most clearly in FIGS. 2 and 3, this recess 3 has a trapezoidal cross section and parallel straight lines. It has a flat bottom surface of 3° and sloped parts 3', 3', and has a small hole 4 in the recess 3 that communicates with the recess 3 on the back side from the recess 3 on the front side. They will be installed side by side. Note that the recesses 3 are not linear as shown in FIG. 3, but are curved in a complicated manner to increase the distance from one side to the other side of the metal flat plate 1, and also to extend the distance from the recesses 3 of each row to the recesses of other rows. If the raw material gas is allowed to flow into the 4th stage and passes through a maze-like complicated flow path, it is possible to increase the probability of contact with the discharge field and the contact time. The embodiment shown in FIGS. 6 to 6 is a one-side electrode 10 manufactured for the purpose of increasing the contact probability and contact time between the raw material gas and the discharge field. A titanium plate (using a titanium plate) is processed into a lath net shape, and the lath net is pressed with a pressure roller or the like to flatten the most protruding parts on the front and back surfaces to such an extent that they are not continuous with each other. Therefore, each mesh of the lath net becomes a small hole 4, and the crushed most protruding part becomes a flat part 2. Regular (ploidy) slits are made in the metal flat plate 1 and the metal flat plate 1 is inserted into the slit. The twisted portion when stretched in the direction perpendicular to the curve constitutes the inclined surface 3' or the recessed portion 3. Therefore, this lath mesh-like one side electrode 10 can be easily formed into the above-mentioned complicated shape by combining conventionally known processing methods, and the gas passing through the flat parts 2 arranged in a zigzag pattern,
2.2..., and furthermore, as appropriate, moves toward the opposite side from the small hole 4 as shown by the arrow P in FIG. 6, creating a complicated meandering and vortex flow. Note that the shapes of the front and back surfaces of the one-side electrode 10 obtained by this manufacturing method did not appear symmetrical, and the area ratio of the flat portion 2 to the recessed portion 3 was different between the front and back sides. Board 1
When 1.11 is polymerized on both sides and the raw material gas is supplied to the flow path composed of each recess 3, the internal pressure and flow rate on both sides are approximately constant due to the presence of the small holes 4, and there is no special problem. It turned out that they did not have it.

A counter electrode 12 is superimposed on both the front and back plates of the one side electrode 10 via a ceramic plate 11, respectively.

In other words, the ceramic plate 11 has its inner surface in contact with each flat surface 2 of the one electrode 10 and its outer surface in contact with the inner surface of the other electrode 12 . The ceramic plate 11 is made of alumina with a purity of 96% or more and a thickness of 1 mm or less, and the other electrode 12 is made by applying a conductive paint to the outer surface of the ceramic plate 11. Of course, a thin metal plate or a conductive heat sink may be used.

In the examples illustrated in FIGS. 1 to 3, two ceramic plates 11 are disposed opposite each other with an interval corresponding to the thickness of one side electrode 10, and a frame-shaped sealing agent 2 is attached to the periphery of both.
0, and in the center there is a partition 2 that does not reach the bottom edge.
1 is interposed between two storage chambers SL and S2, and both storage chambers SL are located at the bottom.

A connecting path S3 is formed to connect S2.

Then, one side electrode 10 is placed in both storage chambers Sl and S2.
are stored in each storage chamber S1, and an inlet 23 for the raw material gas is arranged at the upper side of the storage chamber S1 on the other side, and an ozone outlet 24 is arranged at the upper side of the storage chamber S2 on the other side. The inflowing raw material gas first passes through the storage chamber S1 on one side, then flows into the storage chamber S2 on the other side through the connecting passage S3, and finally flows out from the ozone outlet 24.

Therefore, in this case, it is a thermal theory that the direction in which the concave portion 3 of the one side electrode 10.10 continues is the vertical direction in FIG.

Further, on the outside of both the ceramic plates 11, the mating members N and Fi 12 are respectively superposed. Although not shown in the drawings, the device of the present invention is either water-cooled by being immersed in a cooling water circulation tank, or air-cooled by bringing the outer surface of the other electrode 12 into contact with outside air or a cooling air flow.

In the figure, reference numeral 30 denotes a conventionally known power supply device for supplying high-voltage, high-frequency power between the one-side electrode 10 and both phase-side electrodes 12.

r Effects of the Invention In the present invention, as described above, since the flat portion 2 of the one side electrode 10 is superimposed on the ceramic plate 11, the strength of the ceramic plate 11 is reinforced, and the ceramic plate 11 can be made thin. In addition, since creeping discharge and silent discharge are used together, it is possible to prevent fatigue of the ceramic plate 11 that burdens the power supply due to peak current, and the ceramic plate 11 can be made thin. In addition, since the one side electrode 10, the ceramic plate 11, and the other side electrode 12 have surfaces that are in contact with each other, although not the entire surface, the heat generated by the discharge is highly thermally conducted to the outermost side electrodes 12 and 12. It is possible to provide an ozone generator that can efficiently remove discharge heat by cooling both phase and side electrodes.

Furthermore, in the Kimoto invention, by arranging the small hole 4 in the recess 3,
The raw material air may move from one side of the one side electrode 10 to the other side, and the curved flow at this time disturbs the airflow and causes a vortex, which mixes the raw material gas and prevents the entire amount from coming into contact with the discharge field. Therefore, it is possible to provide an ozone generator that always generates ozone with stable efficiency.

Furthermore, it should be noted that the ozone generator of the present invention has a five-layer structure consisting of one side electrode 10, a pair of ceramic plates 11 and 11, and a pair of opposite electrodes 12 and 12, so that it can be constructed thin as a whole, and it is amphoteric. Since the opposite electrodes 12 and 12 are electrically of the same polarity on the surface side, discharge heat can be efficiently removed by a simple method such as immersing the entire body in a cooling water tank.

[Brief explanation of the drawing]

Fig. 1 is a front view showing an embodiment of the ozone generator of the present invention, Fig. 2 is an enlarged sectional view taken along the line A-A, Fig. 3 is a plan view of one side electrode used in the present invention, and Fig. 4. 5 is a plan view of one side electrode in another example, 5th is a bottom view of the same one side electrode,
FIG. 6 is an enlarged sectional view taken along line B-B.

Claims (1)

[Scope of Claims] A large number of flat parts 2, 2, 2... arranged on the same plane on both the outermost surfaces of the front and back surfaces of a flat metal plate 1,
The parts other than each flat part 2 are formed with a large number of recesses 3, 3, 3, etc. which become deeper in order in the direction away from the flat part 2, and each recess 3 is at least one side of the metal flat plate 1. The metal flat plate 1 has a small hole 4 that communicates from the recess 3 on the front side to the recess 3 on the back side to form a thin plate-like one side electrode 10. This ozone generator is formed by superimposing opposing electrodes 12 on both the front and back surfaces of the one-side electrode 10 via ceramic plates 11, respectively.