JP6067152B2 - Ozone generator - Google Patents

Description

  The present invention relates to an ozone generator, and more particularly to an ozone generator that industrially generates ozonized gas used in water treatment facilities and the like.

  The ozonized gas contains a predetermined concentration of ozone. Ozonized gas has deodorizing and bactericidal action and is used in water treatment facilities and the like. Ozone is generated by discharge energy when oxygen or a source gas containing oxygen is circulated in a minute space and a silent discharge is generated by applying a high-frequency electric field to the minute space. Industrially used ozonated gas is generally produced by this method. A minute space for generating silent discharge is formed in the gap between the ground electrode and the dielectric discharge tube (for example, Patent Documents 1 to 3).

  The ground electrode is made of a metal tube such as stainless steel. The dielectric discharge tube is inserted into a ground electrode, and a glass tube having a high voltage electrode inside is used. The high voltage electrode is a thin film in which a metal such as aluminum or nickel is formed on the inner surface of a dielectric discharge tube by plating, thermal spraying, or the like. A high-frequency high-voltage potential is supplied to the high-voltage electrode. The micro discharge generated at the contact portion with the high voltage potential causes the high voltage electrode to deteriorate. In order to suppress contact deterioration of the high-voltage electrode, contact power supply using a power supply brush or the like is used (for example, Patent Document 4).

  Ozone is generated in a very small space. The discharge voltage is proportional to the gap width of the minute space, and if the gap width is not uniform, the ozone generation efficiency decreases (for example, Patent Document 5). In order to lower the operating cost, it is better that the gap width is short. The discharge voltage is reduced and the load on the power supply is reduced. The manufacturing accuracy of the ground electrode and the dielectric discharge tube affects the variation of the gap width. When the gap width is shortened, the influence of the manufacturing accuracy of the ground electrode and the dielectric discharge tube becomes relatively large. In general, a dielectric discharge tube made of glass or the like has a higher absolute accuracy of the outer diameter as the tube diameter is smaller.

  Compared with the same gap width, a smaller diameter ground electrode can provide higher ozone generation efficiency. On the other hand, if the glass tube diameter is too small, the area of the minute space becomes smaller in proportion to the tube diameter, so the amount of ozone generated per discharge tube decreases and the cost per amount generated increases. In a normal ozone generator, the glass tube diameter is selected from several mm to several tens mm in view of the above situation.

JP 2005-216663 A JP 2009-96693 A JP 2013-155073 A JP 2010-64917 A JP 2009-196823 A

  The ozone generator is configured as described above. When forming a conductive film (high voltage electrode) on the inner surface of a dielectric discharge tube, if the tube diameter of the discharge tube is large, a metal film such as aluminum is sprayed inside the discharge tube to form a sufficiently thick conductive film. be able to. However, in an ozone generator using a discharge tube having a high ozone generation efficiency and a tube diameter smaller than 50 mm, it is difficult to put the thermal spraying device in the dielectric tube. Since it becomes impossible to form a sprayed film on the inner surface of the glass tube, for example, a metal is plated to form a conductive film.

  As the plating film becomes thicker, it becomes easier to peel off from the glass. Therefore, only a thin conductive layer can be formed by the plating method. When the film thickness is thin, the film is easily affected by discharge and reactive gas. Even when a slight partial discharge occurs at the power supply portion or the end of the conductive film, the conductive layer is insulated and power supply is delayed. Therefore, if a power supply brush is used without directly supplying power to the conductive film, the cost of the ozone generator increases by the amount of the power supply brush.

  Usually, in order to feed power from the high voltage wiring to the conductive film in the glass tube, a feeding brush is used to suppress deterioration of the contact portion due to discharge. At present, Ni plating is used as a conductive film for small-diameter glass tubes. In Ni plating, since power is supplied through an oxide film on the surface, brush-like power supply is required. Since plating cannot be formed on a pre-sealed glass tube, pre-sealing is performed after the plating is formed. The pre-sealing cost cannot be ignored for measures such as Ni plating deterioration due to high temperatures during processing.

  That is, in the ozone generator, when the diameter of the glass tube used for the ozone generating tube is large, an aluminum sprayed film that is sufficiently thick and resistant to discharge or the like can be used. On the other hand, in an ozone generator having a high ozone generation efficiency and a small glass tube diameter, a plating film that is weak against discharge and corrosive gas has been used. When the high voltage electrode is manufactured by plating with an ozone generator having high discharge efficiency, the conductive film (plating film) easily deteriorates due to local discharge or a mistake in the operation procedure. The present invention has been made in view of the above-described problems, and an object thereof is to improve the conductive reliability of a high-voltage electrode in an ozone generator.

  An ozone generator according to the present invention includes a casing having a source gas chamber into which source gas flows and an ozone gas chamber into which ozonized gas flows out, and is disposed inside the casing and has a cylindrical cavity inside A ground electrode having one end sealed, and a glass tube having a solder film formed on the inner surface, and a high-frequency power source for supplying a potential to the solder film via a power supply line, the glass tube being grounded The solder film is disposed concentrically in the cavity of the electrode, and the solder film contains a rare earth element.

  In the ozone generator according to the present invention, the conductive film is formed on the inner surface of the glass tube using the rare earth-containing solder attached to the glass. In the case of a solder film, since it has a film thickness of 10 μm or more, even if the surface is slightly insulated by oxidation, the entire film is kept conductive, so that high conductive reliability can be obtained.

It is a schematic side view which shows the ozone generator by Embodiment 1 of this invention. It is a model front view which shows the ozone generator by Embodiment 1 of this invention. It is a model side view which shows the ozone generator by Embodiment 2 of this invention.

  Embodiments of an ozone generator according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited to the following description, In the range which does not deviate from the summary of this invention, it can change suitably.

Embodiment 1 FIG.
FIG. 1 is a schematic diagram showing an ozone generator according to Embodiment 1 of the present invention. In the present embodiment, one discharge tube is arranged in the ozone generator 100. In the figure, an ozone generator 100 includes a ground electrode 2, a glass tube 3, a raw material gas chamber 8, an ozone gas chamber 10, a high-voltage high-frequency power source 11, a high-voltage power supply line 12, a housing 14, and the like. The housing 14 includes a source gas chamber 8 and an ozone gas chamber 10. Oxygen source gas 7 containing oxygen is introduced into source gas chamber 8. The ozone gas 9 generated by the silent discharge flows out from the ozone gas chamber 10 to the outside. The ground electrode 2 has a tubular partition wall 6 inside. The high voltage power supply line 12 is connected to the high voltage electrode 1. The tip of the glass tube 3 is hemispherically sealed in order to stop the gas flow. The glass tube is pre-sealed by following the steps of heating the glass tube, melting the glass tube, and shaping the glass tube. Cooling water 5 is supplied to the ground electrode 2. A gap (discharge gap 4) is formed between the glass tube 3 and the ground electrode 2.

  FIG. 2 shows the relationship between the ground electrode 2 and the glass tube 3. The ground electrode 2 has a cylindrical cavity 2a inside. The high voltage electrode 1 is formed all around the inner surface of the glass tube 3. The glass tube 3 is concentrically disposed in the cavity 2 a of the ground electrode 2. Silent discharge occurs in the gap (discharge gap 4) formed between the glass tube 3 and the ground electrode 2. As a normal high voltage electrode, a plating film or an aluminum sprayed film is used. In this embodiment, a solder film made of a rare earth-containing solder is used for the high voltage electrode 1.

  The rare earth-containing solder has a property that it adheres to the glass by applying ultrasonic waves at the time of bonding to the glass. High voltage high frequency is applied from the high voltage high frequency power source 11 to the glass tube conductive film thus prepared. Since the high voltage electrode 1 according to the present embodiment has high adhesive strength with glass, it has sufficient adhesive strength. The glass tube is pre-sealed before the solder film (high voltage electrode 1) is formed.

  Since the high voltage electrode 1 is a solder film, it has a film thickness of 10 μm or more. Even if the surface of the solder film is slightly insulated by oxidation, the entire film remains conductive, and therefore has high conductive reliability. Moreover, since it is a solder film, the high voltage electrode 1 can be easily joined to the high voltage power supply line 12 by soldering. In the case of a rare earth-containing solder corresponding to glass, the high-voltage power supply line 12 can be directly joined to the inner surface conductive film, so that a power supply brush is not necessary. The high voltage feeder 12 and the high voltage electrode 1 can be stopped with a metal tape.

  If the head of the aluminum sprayer is small, one with a diameter of about 50 mm can be obtained. If the inner diameter of the glass tube is larger than φ50, an aluminum film can be formed by thermal spraying. If the length of the glass tube is less than 300 mm, since it is short, aluminum may be sprayed from the entrance. A conductive film formed by aluminum spraying is less expensive than a conductive film formed by a rare earth-containing solder, and a connection without using a power supply brush is possible by applying a tape-shaped power supply line to the inner surface of the glass in advance and then spraying. The film thickness of the metal plating formed on the inner surface of the glass tube is usually about 1 μm even if it is thick, but the high voltage electrode 1 according to the present embodiment has a film thickness of 10 μm or more, and therefore has long-term reliability. .

  Next, the operation will be described. High voltage high frequency is applied to the high voltage electrode 1 from a high voltage high frequency power supply 11 through a high voltage power supply line 12. In this way, a high electric field is generated in the discharge gap 4 provided between the glass tube 3 and the ground electrode 2. Due to this high electric field, a silent discharge is generated in the discharge gap 4, and the raw material gas 7 undergoes a chemical change, and a part thereof is ozonized. The ozone gas 9 generated in the ozone gas chamber 10 reaches the ozone pipe.

  In the ozone generator according to the present invention, a conductive film is formed on the inner surface of a glass tube (dielectric discharge tube) using rare earth-containing solder adhering to glass. The conductive film according to the present invention exhibits its effect particularly when a discharge tube is formed using a glass tube having an inner diameter of φ50 mm or less and a length of 300 mm or more. By pre-sealing the glass tube before forming the conductive layer, deterioration of the conductive layer due to heat input associated with the pre-sealing can be suppressed.

Embodiment 2. FIG.
FIG. 3 is a schematic diagram showing an ozone generator according to Embodiment 2 of the present invention. The figure is a schematic view of an ozone generator in which a plurality of discharge tubes are arranged. The ozone generator 100 includes a high voltage electrode 1, a ground electrode 2, a glass tube 3, a raw material gas chamber 8, an ozone gas chamber 10, a high voltage high frequency power supply 11, a common high voltage power supply line 13, and the like. Oxygen source gas 7 containing oxygen is introduced into source gas chamber 8. Cooling water 5 is supplied to the ground electrode 2. The high voltage electrode 1 is formed on the entire inner periphery of the glass tube 3.

  The ground electrode 2 has a tubular partition wall 6 inside. The ground electrode 2 is arranged on the coaxial outer peripheral portion of the glass tube 3 via a gap (discharge gap 4). The common high voltage power supply line 13 is connected to the high voltage electrode 1. The ozone gas 9 generated by the silent discharge is led out from the ozone gas chamber 10 to the outside. The tip of the glass tube 3 is hemispherically sealed in order to stop the gas flow. The glass tube is pre-sealed by following the steps of heating the glass tube, melting the glass tube, and shaping the glass tube.

  Next, the operation will be described. High voltage high frequency is applied to the high voltage electrode 1 from a high voltage high frequency power supply 11 through a high voltage power supply line 12. In this way, a high electric field is generated in the discharge gap 4 provided between the glass tube 3 and the ground electrode 2. Due to this high electric field, a silent discharge is generated in the discharge gap 4, and the raw material gas 7 undergoes a chemical change, and a part thereof is ozonized. The ozone gas 9 generated in the ozone gas chamber 10 reaches the ozone pipe.

  In the ozone generator according to the present invention, a conductive film is formed on the inner surface of a glass tube (dielectric discharge tube) using rare earth-containing solder adhering to glass. The conductive film according to the present invention exhibits its effect particularly when a discharge tube is formed using a glass tube having an inner diameter of φ50 mm or less and a length of 300 mm or more. By pre-sealing the glass tube before forming the conductive layer, deterioration of the conductive layer due to heat input associated with the pre-sealing can be suppressed.

  It should be noted that the present invention can be freely combined with each other within the scope of the invention, and each embodiment can be appropriately modified or omitted.

1 high voltage electrode, 2 ground electrode, 2a cavity, 3 glass tube,
4 Discharge gap, 5 Cooling water, 6 Bulkhead, 7 Source gas,
8 Raw material gas chamber, 9 Ozone gas, 10 Ozone gas chamber,
11 high voltage high frequency power supply, 12 high voltage power supply line,
13 common high voltage feeder, 14 housing, 100 ozone generator.

Claims (4)

A housing having a source gas chamber into which source gas flows and an ozone gas chamber from which ozonized gas flows out;
A ground electrode disposed inside the housing and having a cylindrical cavity inside;
A glass tube with one end sealed and a solder film formed on the inner surface;
A high frequency power supply for supplying a potential to the solder film via a power supply line,
The glass tube is disposed concentrically in the cavity of the ground electrode,
The ozone generator according to claim 1, wherein the solder film contains a rare earth element.   The ozone generator according to claim 1, wherein the power supply line is joined to the solder film.   The ozone generator according to claim 1 or 2, wherein the glass tube has an inner diameter of 50 mm or less and a tube length of 300 mm or more. A housing having a source gas chamber into which source gas flows and an ozone gas chamber from which ozonized gas flows out;
A ground electrode disposed inside the housing and having a cylindrical first cavity and a tubular second cavity inside;
A first glass tube having one end sealed and a first solder film formed on the inner surface;
A second glass tube having one end pre-sealed and a second solder film formed on the inner surface;
A high-frequency power source for supplying a potential to the first solder film and the second solder film via a power supply line,
The first glass tube and the second glass tube are disposed concentrically in the first cavity and the second cavity, respectively, and the first solder film and the second solder film are made of rare earth elements. An ozone generator characterized by comprising.

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