JP2799812B2 - Ozone generator - Google Patents

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 an ozone generator in which a gasket for holding a gap between discharge plates of electrodes is formed of fluororesin.

[0002]

2. Description of the Related Art As shown in FIG.
A raw material gas such as O ₂ is passed between the discharge plates 2 and 2 of the high-pressure side electrode 1 and the low-pressure side electrode 1 ′ facing each other.
By applying a high voltage to 1 'to induce a discharge phenomenon in the gap between the discharge plates 2 and 2, the source gas is converted into ozone O ₃ . Therefore, the gasket that holds the gap between the two discharge plates 2 and 2 has gas-sealing resistance, ozone resistance,
Withstand voltage is required.

As a gasket of this type, a gasket 4 made of ceramic has conventionally been used as shown in FIG.
A gasket 4 made of a silicone resin having relatively high ozone resistance, as shown in FIG. 5, is attached to both discharge plates 2 through an O-ring 8 serving as a sealing material. Some are bonded to the plate 2.

However, since these gaskets have been developed for an ozone generator having a relatively low concentration, the gasket has a high concentration of 125 g / Nm ³ or more required for a semiconductor production process or the like. When used in an ozone generator, in the case of the gasket of FIG. 4, the O-ring 8 made of rubber causes ozone deterioration early, and in the case of the gasket of FIG. In addition to the problem, the gasket 4 itself made of silicone resin has a problem that it is quickly degraded by ozone. The ozone generator shown in FIG. 6 has solved such a problem. In this apparatus, a gasket 4 for holding a gap between both discharge plates 2 and 2 of electrodes 1 and 1 'is formed of a fluororesin excellent in high concentration ozone resistance and high voltage resistance. It has a structure in which gas seal resistance is ensured by heat welding with the same fluororesin coating film 3 baked on the surfaces of the discharge plates 2 and 2.

[0005]

However, the ozone generator shown in FIG. 6 has the following problems with respect to the thermal welding between the gasket 4 and the coating film 3.

That is, a gasket 4 made of fluororesin
The thermal welding between the discharge plates 2 and 2 and the fluororesin coating film 3 baked on the surfaces of the discharge plates 2 and 2 is performed by heat-discharging the discharge plates 2 and 2
Is heated in advance to the melting temperature of the coating film 3 and the gasket 4, the gasket 4 is sandwiched between the sufficiently heated discharge plates 2, 2, and the weight is maintained at a constant weight for a required time. However, the welding conditions such as the preheating temperature and preheating time of the discharge plates 2 and 2 or the weight added after the gasket 4 is sandwiched and the holding time under the weight are determined by the thickness of the gasket 4 after the welding is completed. That is, the accuracy of the gap L between the two discharge plates 2 and 2 largely depends. Therefore, it is necessary to conduct sufficient tests in advance for these welding conditions and to strictly control them so that a target gap value can be obtained in actual thermal welding. However, the target gap L value to be obtained is extremely small, usually about 1 mm. Therefore, even if the above welding conditions are strictly controlled, the thickness of the gasket 4 after welding can be accurately adjusted to the target gap value L. It is extremely difficult to match. For this reason, the gap L between the discharge plates 2 and 2 varies, and as a result, the discharge voltage also varies and the ozone generation efficiency decreases.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and is intended to thermally bond a gasket 4 made of a fluororesin and a fluororesin coating 3 baked on the surfaces of both discharge plates 2 and 2. In this case, an object of the present invention is to provide an ozone generator which does not require strict control of the welding conditions and can always stably obtain a discharge plate gap L as a target value.

[0008]

In order to achieve the above object, an ozone generator according to the present invention is characterized in that a raw material gas is caused to flow through a gap between both discharge plates 2 and 2 of a high voltage side electrode 1 and a low voltage side electrode 1 'facing each other. In a device for generating ozone by applying a high voltage to the electrodes, a gasket 4 for holding the gap L between the discharge plates 2 and 2 for the high-voltage side electrode and the low-pressure side electrode is formed of a fluororesin having a relatively high melting point. And a fluorine resin coating film 3 having a relatively low melting point baked on the surface of the coating film 3 and heat-sealing at a melting temperature of the coating film 3.

The gasket 4 is formed of a fluororesin having a relatively low melting point, and is baked together with the auxiliary gasket 5 formed of a fluororesin or a glass having a relatively high melting point on the surfaces of the discharge plates 2 and 2. The gasket 4 and the coating film 3 may be thermally welded at a melting temperature of the fluororesin coating film 3 having a low melting point.

[0010]

When the gasket 4 is formed of a high melting point resin and the coating film 3 to be baked on both discharge plates is made of a low melting point fluorocarbon resin and both are fused at the melting temperature of the coating film 3, only the coating 3 side is obtained. Is melted, and the thickness of the gasket 4 does not change due to the melting. Therefore, if the thickness of the gasket 4 is made to match the target gap value in the formation stage in advance, both the discharge plates 2
2 can be maintained at that thickness, and a discharge plate gap always at a target value can be obtained.

A gasket 4 is formed of a low-melting fluororesin, which is formed together with an auxiliary gasket 5 formed of a high-melting resin or glass, a low-melting fluororesin coating 3 baked on the surfaces of the discharge plates 2 and 2, and a gasket. In the case where the gasket 4 is melted at the melting temperature of the coating film 4 and the coating film 3, even if the gasket 4 melts and the thickness changes, the auxiliary gasket 5 that does not melt at all causes the gap L between the discharge plates 2 and 2 to reach its thickness. To hold. Therefore, if the thickness of the auxiliary gasket 5 is made to match the target gap value in advance, a discharge plate gap always equal to the target value can be obtained as in the case described above.

Hereinafter, embodiments of the present invention will be described.

[0013]

1 (a) and 1 (b) are a plan view schematically showing an example of an ozone generator embodying the present invention and a sectional view taken along the line AA.

As shown in FIG. 1, the high-voltage side electrode 1 and the low-voltage side electrode 1 'which are vertically opposed to each other are plate-type electrodes having a radiator structure also serving as a radiator, and a discharge plate is provided on the electrode plate surface. 2 is attached with a dielectric adhesive.

These discharge plates 2 and 2 are formed by coating a metal plate with glass or enamel. The coating surfaces of both discharge plates 2 and 2 are covered with a coating film 3 of a fluororesin (polyfluoroethylene: so-called Teflon) having a relatively low melting point. The coating 3 in the illustrated example has a melting point of 270 ° C.
And a low FEP type fluororesin paint filtered through a mesh of about 200 mesh, and spraying pressure of 2-3 kgf / c
It is applied by a spray gun adjusted to m ² to a film thickness of about 7 to 15 μm, dried (110 ° C. × 10 minutes), and baked (380 ° C. × 15 to 30 minutes).

The gap L between the two discharge plates 2, 2 is held by a frame plate-like gasket 4 disposed at the peripheral portion between the two discharge plates 2, 2. This gasket 4
PFA-based fluororesin (melting point 302-3)
10 ° C.), and the thickness of the sheet material is 0.8 mm, which is the same as the target gap value between the two discharge plates 2. The upper and lower surfaces of the gasket 4 are thermally welded to the coating film 3 baked on the surfaces of the discharge plates 2 and 2 at the melting temperature of the coating film 3. That is, the heat welding between the gasket 4 and the coating film 3 is performed by the two discharge plates 2 and 2 where the coating film 3 is baked.
About 270 ° C. which is the melting temperature of the coating film 3 beforehand.
The heating was carried out for 1 minute, the gasket 4 was sandwiched between the two sufficiently heated discharge plates 2 and 2 and a weight (weight) of 1 kgf was added from above and held for about 1 minute. As a result, the gasket 4 side was not melted at all, and only the coating film 3 side was melted to obtain a welded state, so that the target discharge plate gap of 0.8 mm could be stably obtained. During this thermal welding, the welding conditions such as the heating time of the discharge plate 2 and the holding time under the weight can be roughly estimated, and no strict control was required at all.

FIG. 2 shows another embodiment of the present invention. That is, the gap L between the two discharge plates 2 is held not only with the normal gasket 4 but also with a plurality of auxiliary gaskets 5. In this case, the auxiliary gasket 5 is made of a fluororesin having a relatively high melting point (for example, the aforementioned melting point of 302 to 310 ° C.).
(PFA-based fluororesin) or glass or the like, and the thickness thereof is made to match the target gap value of 0.8 mm. For the material for forming the gasket 4 and the coating film 3 to be baked on the discharge plates 2 and 2, a fluororesin having a relatively low melting point (for example, FEP-based fluororesin having a melting point of 270 ° C.) is used. The length is set to be slightly larger than the target gap value of 0.8 mm. In the heat welding, the two discharge plates 2 and 2 are previously melted at a melting temperature of the coating film 3 and the gasket 4 (270 ° C.).
The gasket 4 is held between the two discharge plates together with the auxiliary gasket 5 for a required time and under a required weight. Then, the gasket 4 melts together with the coating film 3 to reduce the thickness, but the auxiliary gasket 5 does not melt at all and keeps its thickness (0.8 mm) all the time.
Therefore, also in this case, it is not necessary to particularly strictly control the conditions at the time of heat welding, and the discharge plate gap of 0.8 mm can always be stably obtained as a constant target value.

The ozone generating apparatus having the above-mentioned configurations is
In each case, a high voltage is applied to the high-pressure side electrode 1 and the low-pressure side electrode 1 ′, and the raw material oxygen gas is supplied from the gas supply pipe 6 to the gap L between the high-pressure side and low-pressure side discharge plates 2 and 2 held by the gasket 4. (O
₂ ), high-concentration ozone (O ₃ ) is generated in the raw oxygen gas (O ₂ ) by the discharge phenomenon between the discharge plates 2 and 2, and the generated ozone is discharged to the outside through the discharge pipe 7. It has become.

The present invention can be applied not only to a plate-type ozone generator but also to a cylindrical ozone generator, and similar effects can be obtained.

[0020]

As described above, according to the ozone generator of the present invention, it has been conventionally difficult to heat-bond a gasket formed of a fluororesin to a fluororesin coating film baked on the surface of a discharge plate. It is not necessary to strictly control the heat welding conditions, and the discharge plate gap as intended can always be obtained stably. Therefore, the discharge voltage is stabilized, and the generation efficiency of ozone can be greatly increased.

[Brief description of the drawings]

FIG. 1A is a plan view of the device of the present invention, and FIG.
It is sectional drawing in the AA arrow of (a).

FIG. 2 is a sectional view showing another embodiment of the device of the present invention.

FIG. 3 is a diagram illustrating the principle of an ozone generator.

FIG. 4 is a sectional view of a main part for explaining a conventional ozone generator.

FIG. 5 is a sectional view of a main part for explaining another conventional ozone generator.

FIG. 6 is a cross-sectional view of a main part illustrating a conventional high-concentration ozone generator.

[Explanation of symbols]

 L Discharge plate gap 1, 1 'electrode 2 Discharge plate 3 Coating film 4 Gasket 5 Auxiliary gasket

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01T 19/00 C01B 13/11 H01T 23/00

Claims (2)

(57) [Claims] An apparatus for generating ozone by flowing a raw material gas between the discharge plates 2 and 2 of a high-pressure side electrode 1 and a low-pressure side electrode 1 'facing each other and applying a high voltage to both electrodes. And a gasket 4 for holding the gap L between the discharge plates 2 and 2 of the low-voltage side electrode, formed of a fluororesin having a relatively high melting point, and a fluororesin coating film 3 having a relatively low melting point baked on the surfaces of the discharge plates 2. An ozone generator characterized in that the coating film 3 is thermally welded at a melting temperature. 2. An apparatus for generating ozone by flowing a raw material gas between the discharge plates 2 and 2 of a high pressure side electrode 1 and a low pressure side electrode 1 'facing each other and applying a high voltage to both electrodes. The gasket 4 for holding the gap L between the discharge plate 2 and the low-voltage side electrode is formed of a fluororesin having a relatively low melting point, and an auxiliary gasket 5 formed of a fluororesin or glass having a relatively high melting point is formed. An ozone generator characterized in that a fluororesin coating film 3 having a relatively low melting point baked on the surface of each of 2, 2 and the gasket 4 and the coating film 3 are thermally welded at a melting temperature.