Embodiments relate to an ozone generator.
An ozone generator includes a tubular metallic electrode both ends of which are held by end plates, a discharge tube including a conductive film formed inside a tubular dielectric placed inside the metallic electrode, and a high voltage feeding terminal connected to the conductive film. The ozone generator causes a silent discharge in a discharge gap between the metallic electrode and the conductive film, thereby generating ozone. The generated ozone is used for various purposes including advanced water purification treatment, and clarification, sterilization, oxidation, decolorization, and deodorization of industrial waste water and sewage, for example.
Such an ozone generator includes the conductive film and the high voltage feeding terminal extending to the position of the end plate which needs to cause a silent discharge, thereby ensuring a discharge region.
Patent Literature 1: Japanese Patent Application Laid-open No. 2012-144425
The above ozone generator, however, generates an electric field from the outer ends of the conductive film and the high voltage feeding terminal to the end plate, so that anomalous discharge may occur, which would deteriorate the components.
In view of solving the problem and attaining an object, an ozone generator includes a first end plate, a second end plate, a metallic electrode, a dielectric, a conductive film, and a high voltage feeding terminal. The second end plate is located opposite the first end plate. The metallic electrode is tubular and held at both ends by the first end plate and the second end plate. The dielectric is located inside the metallic electrode with a discharge gap, and tubular with an open end on a first end plate side and a closed end on a second end plate side. The conductive film is located on an inner surface of the dielectric. The high voltage feeding terminal is electrically coupled to the conductive film. The conductive film and the high voltage feeding terminal are at least partially in the same position as the first end plate in an axial direction of the dielectric. An end of the conductive film and an end of the high voltage feeding terminal on an opening side of the dielectric extend further toward the opening of the dielectric than the first end plate in the axial direction of the dielectric.
The following exemplary embodiments and modifications include the same or like elements. Thus, same or like elements are denoted by the common reference numerals and overlapping descriptions are partially omitted below. Part of an embodiment or a modification can be replaced with a corresponding part of another embodiment or modification. A structure, position, and the like of part of an embodiment or a modification are similar to those of another embodiment or modification unless otherwise stated.
The apparatus body 12 includes an airtight container 20, a pair of end plates 21a, 21b, a plurality of metallic electrodes 22, a plurality of dielectric electrodes 24, a fuse 40, a spacer 42, and a positioning member 48.
The airtight container 20 has a hollow cylindrical shape having an axis in the Y direction. The airtight container 20 houses and holds the end plates 21a, 21b, the metallic electrodes 22, the dielectric electrodes 24, the fuse 40, the spacer 42, and the positioning member 48. The outer periphery of the airtight container 20 is connected to a gas inlet 27, a gas outlet 28, a cooling water inlet 30, and a cooling water outlet 32. A feed gas containing oxygen is supplied from the outside through the gas inlet 27 into the airtight container 20. The gas outlet 28 discharges an unreacted feed gas and ozone (O3) to the outside. The cooling water inlet 30 is located at the bottom of the airtight container 20. Cooling water flows into the cooling water inlet 30 from the cooling water supplier 16. The cooling water outlet 32 is located at the top of the airtight container 20. The cooling water outlet 32 discharges the cooling water to the outside.
The end plates 21a, 21b contain a conductive material such as stainless steel. The end plates 21a, 21b have a discoid shape. The outer periphery of the end plates 21a, 21b is fixed to the airtight container 20. The end plate 21b is located opposite the end plate 21a in substantially parallel to the end plate 21a. The end plates 21a, 21b are connected to ground potential through the airtight container 20. The end plates 21a, 21b are each provided with a plurality of circular holes 26a, 26b of substantially the same shape as that of an end of the metallic electrodes 22.
The metallic electrodes 22 contain the same material as the end plates 21a, 21b, the material being a conductive material such as stainless steel, and have electrical conductivity. The metallic electrodes 22 are arranged inside the airtight container 20. The metallic electrodes 22 are disposed at substantially equal intervals in the X direction and the Z direction, with the longitudinal side of each metallic electrode 22 extending in the Y direction. The metallic electrodes 22 have a tubular shape (a cylindrical shape, for example) with an axis in the Y direction in parallel to the axis of the airtight container 20. One end of each metallic electrode 22 is coupled to the corresponding circular hole 26a of one of the end plates 21a. The other end of the metallic electrode 22 is coupled to the corresponding circular hole 26b of the other end plate 21b. Thus, both ends of the metallic electrode 22 are not closed but held by the end plates 21a, 21b and are electrically connected to the end plates 21a, 21b. The ends of the metallic electrode 22 are coupled to the end plates 21a, 21b by welding, for example. The metallic electrodes 22 are connected to ground potential through the end plates 21a, 21b. Of the metallic electrodes 22, the metallic electrodes 22 located at the outermost circumference each form a cooling-water channel 46 with the inner circumference of the airtight container 20. The channels 46 are connected to the cooling water inlet 30 and the cooling water outlet 32 of the airtight container 20. The channels 46 are also connected to inner hollows of the metallic electrodes 22 in the middle other than the metallic electrodes 22 located at the outermost circumference.
Each dielectric electrode 24 is located in the airtight container 20 inside any of the metallic electrodes 22. The dielectric electrode 24 includes a dielectric 34, a conductive film 36, and a high voltage feeding terminal 38.
The dielectric 34 contains a dielectric material such as silica glass, borosilicate glass, high silicate glass, aluminosilicate glass, and ceramic, and is electrically isolated. The dielectric 34 has a tubular shape (a cylindrical shape, for example). The dielectric 34 has a length of 60 mm, for example, in the axial direction. The dielectric 34 has an open end on the end plate 21a side. The dielectric 34 has a closed end which tapers toward the tip, on the end plate 21b side. The dielectric 34 is located inside any of the metallic electrodes 22 with a discharge gap 44. The dielectric 34 is placed such that the axis of the dielectric 34 is in substantially parallel to the axes of the airtight container 20 and the metallic electrodes 22 and that the outer circumference of the dielectric 34 opposes the inner circumferences of the metallic electrodes 22. The end of the dielectric 34 on the opening side protrudes more outward than the end plate 21a.
The conductive film 36 contains a conductive material such as stainless, nickel, carbon, or aluminum, and has electrical conductivity. The conductive film 36 is formed on the inner surface of the dielectric 34 by sputtering, thermal spraying, vapor deposition, electroless plating, electrolytic plating, or coating, for example, of a conductive material. Thus, the conductive film 36 has a tubular shape (a cylindrical shape, for example).
The high voltage feeding terminal 38 contains a conductive material and has electrical conductivity. For example, the high voltage feeding terminal 38 has a porous columnar structure made of a fibrous conductive material. The high voltage feeding terminal 38 is placed in the vicinity of the end of the dielectric 34 on the end plate 21a side. The high voltage feeding terminal 38 is electrically connected to the conductive film 36 and the fuse 40.
The fuse 40 is placed with the axis thereof coinciding with the axis of the dielectric 34. One end of the fuse 40 is electrically connected to the high-voltage power supply 14 through a high-voltage insulator 14a. The other end of the fuse 40 is electrically connected to the high voltage feeding terminal 38. In the case of a breakage of the dielectric 34 due to a dielectric breakdown, the fuse 40 serves to interrupt an overcurrent flowing through the conductive film 36 and isolates a broken discharge tube from the other discharge tubes. Thereby, the ozone generator can continue the operation.
The spacer 42 is located between the corresponding metallic electrode 22 and the dielectric electrode 24. Thus, the spacer 42 maintains the discharge gap 44 between the metallic electrode 22 and the conductive film 36 at a certain gap. Specifically, the spacer 42 retains the discharge gap 44.
Each positioning member 48 positions the corresponding dielectric electrode 24 in the axial direction. The positioning member 48 is located on the inner surface of the metallic electrode 22, and abuts on the closed end of the dielectric 34 on the end plate 21b side when inserted into the metallic electrode 22. In this manner, the positioning member 48 restrains the dielectric 34 from being inserted deeper into the metallic electrode 22, thereby positioning the dielectric 34 of the dielectric electrode 24.
The high-voltage power supply 14 is connected to the high voltage feeding terminal 38 through the fuse 40. The high-voltage power supply 14 applies a high alternating voltage to the conductive film 36 through the fuse 40 and the high voltage feeding terminal 38.
The cooling water supplier 16 represents a chiller or a pump, for example. The cooling water supplier 16 is connected to the cooling water inlet 30 of the airtight container 20, and supplies cooling water from the cooling water inlet 30 to the channel 46 inside the airtight container 20.
The operation of the ozone generator 10 is described next. The ozone generator 10 is supplied with a feed gas through the gas inlet 27 and the high-voltage power supply 14 supplies an alternating voltage between the metallic electrodes 22 and the respective conductive films 36 while the metallic electrodes 22 is cooled by cooling water supplied through the cooling water inlet 30. Thereby, the feed gas between the conductive film 36 and the metallic electrodes 22 is applied with a high voltage, and a silent discharge occurs in the discharge gap 44, which causes ozone from oxygen in the feed gas, and the ozone is discharged from the gas outlet 28.
As illustrated in
As described above, in the ozone generator 10, the end of the conductive film 36 and the end of the high voltage feeding terminal 38 can be longer in distance from the end of the metallic electrode 22 and the end plate 21a, as compared with both of them being in the same position as the end of the metallic electrode 22 and the end plate 21a. Thereby, the ozone generator 10 can be downsized, with the high voltage feeding terminal 38 being partially located in the same position as the end plate 21a, and can prevent an anomalous discharge by relaxing the electric field between the high voltage feeding terminal 38, and the end plate 21a and the metallic electrode 22. As a result, the ozone generator 10 can prevent the conductive film 36 from being damaged, and elongate the longevity of the dielectric electrode 24.
In the ozone generator 10, the positioning member 48 can facilitate the positioning of the dielectric 34 of the dielectric electrode 24.
The following describe simulations for proving the effects of the respective embodiments.
It is seen from illustrated in
It is seen from
It can be seen from
While certain embodiments of the present invention have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. These novel embodiments may be embodied in a variety of other forms, and various omissions, substitutions and changes may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover these embodiments or modifications thereof as would fall within the scope and spirit of the inventions.
Number | Date | Country | Kind |
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2017-028189 | Feb 2017 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2017/033783 | 9/19/2017 | WO | 00 |