JP2003002615A - Electric discharge-type ozonizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric discharge-type ozonizer which can keep a gap between an insulator and an anode always constant and uniform and attain the yield of ozone with high efficiency. SOLUTION: This ozonizer contains an ozone generating unit formed by inserting an insulator between a cathode and an anode in an electric discharge space, which has an inlet of a starting gas at one end and an outlet of a product gas at the other end, in a tank equipped with a starting gas supplying unit and a product gas discharging unit. The inlet of the starting gas of the ozone generating unit is opened to the inner space of the tank and the outlet of the product gas is closed to the inner space of the tank but connected to the outlet of the product gas of the tank.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ozone generator, and more particularly to a discharge ozone generator.

[0002]

2. Description of the Related Art Conventionally, as an ozone generator, for example, as disclosed in Japanese Patent Publication No. 4-745281, a discharge space is formed between an anode and a cathode through an insulating film, and a raw material containing oxygen is formed in this space. A method is known in which a source gas is ozonized by applying a high-frequency high-frequency voltage while flowing a gas (oxygen, air, etc.) to form a discharge field. However, in the method described in the publication, since the contact portion between the insulator (dielectric layer) and the anode is formed by surface contact, current flows in this portion where there is no gas flow, and therefore the input power is reduced. There is a problem that a part of the heat is consumed as wasted Joule heat without contributing to ozonization. Therefore, the inventors previously proposed a new device configuration in which a large number of protrusions are formed on the front and back surfaces of the anode and the contact portion with the insulating film is point contact (see Japanese Patent Laid-Open No. 9-241005), We came to solve this problem. With this proposal, the amount of product ozone generated per input electric power is significantly increased as compared with the above-mentioned conventional type, and it has been highly praised by the industry for providing a device with excellent productivity.

However, when the inventors further conducted experiments and studies after the commercialization of this new device, it was found that there is still room for improvement in its efficiency.
The problems of this ozone generator will be described below with reference to the drawings.

6 and 7 are a plan view and a vertical sectional view showing the basic structure of this apparatus. Here, 1 is an anode, 2 is an insulator, 3 is a frame, 4 is a high voltage cable, 5
Is a source gas supply port, 6 is a product gas outlet, 7 is a cathode, and 8 is a discharge space. Two parallel plate-shaped upper and lower cathodes 7, 7 each having a film-shaped insulator 2 lined therein are arranged facing each other with a constant space, that is, a discharge space 8, in which the anode 1 is vertically arranged. The insulators 2 and 2 are inserted and arranged so as to be partially in point contact with each other, and these are supported and fixed by the frames 3 and 3. Note that the anode 1 is actually a mesh-like structure having a large number of protrusions formed on the upper and lower sides, such as expanded metal, but here, in order to make the description easier to understand, a simple structure in which the peaks and valleys are repeated is shown in the figure. It is schematically shown in a zigzag shape. And the top of each mountain valley is
It becomes a point contact portion C between the anode 1 and the insulators 2 and 2 (see an enlarged portion surrounded by a circle in FIG. 1).

Therefore, when the ozone production operation is performed by such an apparatus, a raw material gas such as oxygen is introduced into the discharge space from the raw material gas supply port 5 and a high frequency high voltage is applied via the high voltage cable 4. It is applied between the anode 1 and the cathodes 7, 7. Then, first, the anode 1 and the insulator 2,
In 2, pre-ionization occurs and discharge starts. By the start of this discharge, the electron density around the area increases, and as a result, the discharge phenomenon spreads from these point contact portions C toward the discharge space 8 around it. As a result, the raw material gas flowing in the discharge space 8 is gradually ozoned and finally becomes a product gas and flows out from the product gas outlet 6. At this time, since the portion where the anode 1 and the insulators 2 and 2 are in direct contact is only the point contact portion C, and the contact area is close to zero, the input power contributes to ozone generation energy with almost no loss. As a result, superior ozone generation efficiency can be achieved as compared with the conventional surface contact type device.

Even in this apparatus, in order to maintain good ozone generation efficiency, the discharge region and the gas flow path in the discharge space 8 must be substantially aligned with each other. The discharge is stronger as the gap between the insulators 2 and 2 and the anode 1 is smaller. On the other hand, the larger this gap, the more gas flow. FIG. 8 is a schematic sectional view similar to FIG. 6, but shows this relationship when a large amount of gas flows to the left side and a small amount of gas flows to the right side of FIG.
The gap G between the point contacts between the insulators 2 and 2 and the anode 1 is large on the left side and small on the right side. As a result, the discharge appears on the contrary, with the right side being strong and the left side being weak. Such a phenomenon may occur due to partial pressure fluctuations in the discharge space even during normal operation, and it should be noted that this phenomenon adversely affects the ozone generation efficiency.

In particular, since this device needs to be operated under a high pressure to some extent, a pressure of about 1 kgfcm ² is applied to the discharge space 8. Thus, when the internal pressure of the discharge space 8 rises when the pressure is high, what is constant at any position when the pressure is low as shown in the diagram on the left side of FIG.
As shown in the figure on the right side of the figure, the central part deforms outward and swells, the gap G increases and the discharge in this part weakens,
A large amount of gas flow is generated, that is, the discharge region and the gas flow path do not match with each other, resulting in a reduction in ozone generation efficiency.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and always maintains a constant and uniform gap between the insulator and the anode in the discharge space. It is an object of the present invention to provide an ozone generator capable of stably achieving high ozone generation efficiency.

[0009]

As a means for solving the above problems, in a first aspect of the present invention, a tank provided with a raw material gas feeding section and a product gas discharging section is provided with an insulator between a cathode and an anode. An ozone generator configured to have a raw material gas supply port at one end and a product gas outlet at the other end of the discharge space formed through, and to supply the raw material gas to the ozone generator. The mouth is opened to the internal space of the tank, while the product gas outlet of the ozone generator is cut off from the internal space of the tank so as to communicate with the product gas discharge part of the tank. A characteristic discharge ozone generator is proposed.

According to a second aspect of the present invention, in the ozone generator, a flat-plate cathode having an insulator stretched on the lower surface is the uppermost layer, and a flat-plate cathode having an insulator stretched on the upper surface is the ozone generator. As a lowermost layer, a flat plate-shaped cathode in which insulators are stretched on both upper and lower surfaces between them is laminated as an intermediate layer to form one or more layers, and a discharge is formed between the insulator on the upper and lower surfaces of each cathode and the insulator on the lower upper surface. 2. A discharge type ozone generator as claimed in claim 1, characterized in that the discharge type ozone generator has a laminated structure constituted by forming a space and providing an anode in each of the discharge spaces, the anode being in partial contact with the insulators on the lower surface and the upper surface. Is.

According to a third aspect of the present invention, the anode provided in the discharge space of the ozone generator is formed in point contact with the insulators on the lower surface and the upper surface. The discharge type ozone generator according to claim 2, further, in claim 4, a through hole communicating with each discharge space is formed on the product gas extraction side of the ozone generator having the laminated structure, and The discharge type ozone generator according to claim 2 or 3, wherein one end is used as the product gas outlet and is connected and communicated with the product gas discharge portion of the tank by a single pipe. is there.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic side view of an apparatus according to the present invention, where U is an ozone generator, T is a strong metal tank (main body), and C is a cap of the tank. Although details are omitted, the ozone generator U has a laminated structure in which a plurality of parallel plate-shaped ones of the same type as those in FIG. 6 are laminated (hereinafter, may be referred to as a plural laminated type).
And a discharge space 8 is formed between each cathode 7 having a thickness of about 20 mm with a film-like insulator (not shown) of about several hundred μ at an interval of about 0.5 mm.
An anode is inserted and arranged in this space 8 as in FIG. Therefore, an insulator is stretched (lined) exactly as in FIG. 6 on the lower surface of the flat plate-shaped cathode 7 of the uppermost layer and the upper surface of the same cathode 7 of the lowermost layer. The cathode 7 forming the intermediate layer between them has a structure in which insulators are provided on both the upper surface and the lower surface.

A material gas supply port 5 is provided at one end (left end in the figure) of the discharge space 8 of the ozone generator U, and a product gas outlet 6 is provided at the other end (right end in the figure). . Here, the product gas outlet 6 has a structure in which an outlet pipe 9, a manifold 10 and an exhaust pipe 11 are sequentially connected as in the conventional case, but the source gas supply port 5 remains open (open) in layers. With the configuration, no connection structure such as supply piping is attached. That is, as shown in FIG. 2 which is a side view of the raw material gas supply side, all the raw material gas supply ports 5 having four layered slits are exposed.

In the ozone generator of the present invention, the ozone generator U having the above structure is inserted and fixed in the cylindrical tank body T as shown by the arrow, and then the tank cover C is provided on both bodies. It is assembled by fixing it airtightly through the seal member by the flange.

Further, a hole 13 is provided in advance at the upper end side (right side in the drawing) of the tank body T in accordance with the position of the discharge pipe 11 when the ozone generator U is fixed in the tank.
When the same generator U is incorporated, a product gas discharge pipe 11
A tank discharge short pipe 14 separately prepared from directly above is inserted so that a part thereof protrudes to the upper part of the tank, and is connected with the discharge pipe 11 by screwing, and this is the product gas on the tank side. It becomes the discharge part. After the discharge short pipe 14 is connected, the gap between the outer circumference of the short pipe 14 and the hole 13 is eliminated by welding or the like to maintain the airtightness. In addition, this discharge short pipe 14
Is connected to an ozone recovery store (not shown).

On the other hand, a hole 15 is also provided in the central portion of the lid C of the tank, and a raw material gas feed pipe 16 is connected and fixed to the hole 15. The pipe end outlet of the feed pipe 16 is directly opened in the tank, and as described above, the ozone generator U
It does not have a structure connected to the raw material gas supply port 5 by a pipe or the like. The source gas supply pipe 16 is connected to a source gas supply source (not shown).

Now, the operation of the above embodiment will be described. When the ozone gas is generated by this device, a raw material gas such as oxygen is once fed into the tank T through the raw material gas feed pipe 16 and then supplied from the raw material gas supply port 5 of the ozone generator U to the discharge space 8. Then, while discharging and ozoneizing the product gas, the product gas is caused to flow out from the product gas discharge port 6, and is discharged and collected outside the tank through the discharge pipe 9, the manifold 10, the discharge pipe 11 and the discharge short pipe 14.

As described above, in this apparatus, the ozone generator is airtightly contained in the tank, and the raw material gas supply port serving as the inlet of the discharge space is placed inside the tank in an open state. Since the dynamic pressure of the raw material gas once supplied to the tank is converted into static pressure, the pressure outside the ozone generator and the pressure in the discharge space are maintained at the same pressure.

Therefore, even when a high pressure is applied to the discharge space, there is no difference or a very small value with the pressure outside it, that is, the pressure inside the tank, and the value is extremely small. The occurrence of such deformation does not occur, and the gap between the insulator and the anode can always be kept constant.

As a result, the discharge region of the ozone generator and the gas flow path can be matched in a well-balanced manner according to the device design, and can be stably maintained.
The ozone generation efficiency can be improved.

Further, according to the present embodiment, since the raw material gas supply port 5 is opened inside the tank T, even if the ozone generator is of a type in which a plurality of ozone generators are stacked, a manifold or the like can be provided as in the conventional case. Since it is not necessary and only one source gas supply means is required, the size and weight of the apparatus can be reduced.

FIG. 3 is a graph showing the degree of improvement in ozone generation efficiency according to this embodiment. The power consumption (W) due to the operation of the apparatus and the maximum concentration of product ozone (g / m ² ) at that time are shown.
The graph of A is the result of the apparatus of the embodiment of the present invention having a built-in tank, and the graph of B is the result of the conventional apparatus having no built-in tank. All of them were parallel plate-shaped laminated types, and the capacities of the apparatus main body (ozone generator) were exactly the same. As is apparent from the above, it can be seen that the device of the embodiment of the present invention has a higher ozone generation efficiency than the conventional device, and the difference becomes larger particularly as the power consumption increases.

Next, another embodiment according to the present invention will be described with reference to FIG. FIG. 4 shows a perspective view of the ozone generator U to be built in the tank. Since this ozone generator is the same parallel plate-like plural laminated type as that of the above embodiment with respect to its basic structure, In the following, the above-mentioned duplication will be avoided and the structure peculiar to this embodiment will be mainly described.

In the main body mode, a total of eight flat plate-shaped cathodes 7 whose outer sides are integrated by a U-shaped frame 3 are laminated, and as shown in the exploded view of the upper part, the same frame 20 is formed.
A spacer 21 having a substantially U-shape is sandwiched between the upper and lower frames 3, and a discharge space corresponding to the thickness of the spacer 21 and the planar shape of the cathode 7 is formed inside the spacer 21. The raw material gas supply port 5 is open to communicate with this discharge space. Although the anode 1 is arranged in the discharge space, the anode 1 is shorter than the length of the discharge space, and a complete space, that is, a product gas discharge space 22 is formed on the product gas discharge side. Each cathode 7 corresponding to this gas extraction space 22 is provided with a through hole 23 which is vertically communicated with the cathode 7 except for the uppermost layer. The lower end of the cathode 7 in the lowermost layer of the through hole 23 becomes the product gas outlet 6. The product gas outlet 6 and the discharge short pipe 14 serving as the product gas discharge portion of the tank are connected by a single discharge pipe 9.

By the way, the cathode 7 in this embodiment is
The ozone generator U has a flat plate shape for cooling and also has a cooling water passage (not shown) therein, and 24 and 25 are cooling water supply for supplying and discharging the cooling water to and from the cooling water passage, respectively. The pipe and the discharge pipe are shown. Although not shown,
Film-shaped insulators 2 formed by spray coating are lined on the lower surface of the upper cathode 7, the upper surface of the lower cathode 7, and the upper and lower surfaces of the intermediate cathode 7. In addition, 2 in the figure
Reference numeral 6 denotes a U-shaped insulating plate fitted inside the spacer 21 and disposed on the frame 3.

The operation of the above embodiment will be described below.
Since the through holes 23 communicating with the discharge spaces 8 are provided on the product gas outlet side of the multi-layer type ozone generator U, a manifold or the like which is conventionally required for taking out the product gas is not required, and the device It is possible to reduce the size and weight.

Further, supplementing the other embodiments,
Regarding the shape of the tank T in which the ozone generator U is incorporated, a cylindrical shape as shown in FIG. 1 is illustrated in the description of the first embodiment, but a plurality of flat ozone generators U are stacked. In the case of the type, a rectangular parallelepiped shape as shown in FIG. 5 can be mentioned as a preferable example. According to this aspect, since the ozone generator and the tank have similar shapes, there is an advantage that the dead space of the entire apparatus is eliminated and the size can be reduced.

[0028]

As described above, according to the discharge-type ozone generator of the present invention, the gap between the insulator and the anode in the discharge space is always kept constant and uniform, and is stable and high. It has an excellent effect of achieving ozone generation efficiency.

[Brief description of drawings]

FIG. 1 is a schematic side view showing an embodiment of the device according to the present invention.

FIG. 2 is a partial front view showing an embodiment of the device according to the present invention.

FIG. 3 is a graph comparing ozone generation efficiency based on the operation results of the device according to the present invention and the conventional device.

FIG. 4 is a perspective view showing another embodiment of the device according to the present invention.

FIG. 5 is a perspective view showing yet another embodiment of the device according to the present invention.

FIG. 6 is a schematic side sectional view of a conventional device.

FIG. 7 is a schematic plan view of a conventional device.

FIG. 8 is a schematic side sectional view for explaining a problem (phenomenon) of a conventional device.

FIG. 9 is a schematic side sectional view for explaining a problem (phenomenon) of a conventional device.

[Explanation of symbols]

1: Anode 2: Insulator 3: Frame 4: High-voltage cable 5: Raw material gas supply port 6: Product gas outlet 7: Cathode
8: Discharge space 9: Product gas extraction pipe 10: Manifold 11: Product gas discharge pipe 14: Product gas discharge short pipe 16: Raw material gas supply pipe 2
1: Spacer 22: Product gas extraction space 23: Through hole U: Ozone generator T: Tank (main body) G: Gap
C: Point contact part

Continued front page    (72) Inventor Tomohiro Daifukuchi             1-3-18 Wakihama-cho, Chuo-ku, Kobe-shi, Hyogo               Kobe Steel, Ltd. Kobe Head Office F-term (reference) 4G042 CA01 CC02 CC05 CC10 CC11                       CC23

Claims (4)

[Claims] 1. A tank provided with a raw material gas supply section and a product gas discharge section has a raw material gas supply port at one end of a discharge space formed between a cathode and an anode via an insulator and the other end. An ozone generator configured to have a product gas outlet therein, and the raw material gas supply port of the ozone generator is opened to the internal space of the tank, while the product gas outlet of the ozone generator is provided. An electric discharge type ozone generator characterized in that the outlet is arranged so as to be in communication with the product gas discharge portion of the same tank by blocking the internal space of the same tank. 2. The ozone generator has a flat-plate cathode having an insulator stretched on the lower surface as the uppermost layer, and a flat-plate cathode having an insulator stretched on the upper surface as the lowermost layer, with the upper and lower surfaces sandwiched therebetween. The cathode is formed by stacking one or more flat plate-shaped cathodes each having an insulator stretched as an intermediate layer, and a discharge space is formed between an insulator on the lower surface of the upper layer and an insulator on the upper surface of the lower layer. 2. The discharge type ozone generator according to claim 1, wherein an anode that partially contacts the insulators on the lower surface and the upper surface is provided in the laminated structure. 3. The discharge type ozone generator according to claim 2, wherein an anode provided in a discharge space of the ozone generator is configured to be in point contact with the insulators on the lower surface and the upper surface. 4. A product of the tank, wherein a through hole communicating with each discharge space is formed on the product gas outlet side of the ozone generator having the laminated structure, and one end of the through hole is used as the product gas outlet. The discharge type ozone generator according to claim 2, wherein the gas discharge part is connected and communicated with a single pipe.