JP2008222495A - Ozone generation apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ozone generation apparatus where a high voltage electrode does not corrode in emergency stop and the like so that gas pressure is not applied to a dielectric discharge tube. <P>SOLUTION: The ozone generation apparatus where an ozonized gas being an ozone-containing gas is generated by electric discharge from an oxygen-containing raw material gas comprises the cylindrical dielectric discharge tube 3 where a gas flow plug 16 with a gas flow port 17 is located at an end of the flowing side of the raw material gas and where another end is closed, the cylindrical high voltage electrode 1 located at the inside of the dielectric discharge tube 3 and applied with AC voltage, a grounding electrode 2 being a metallic cylindrical tube and being located at the outside of the dielectric discharge tube 3 with specified intervals, a high voltage power supply 8 to apply AC voltage to the high voltage electrode 1 and a raw material gas supply part 11 to flow the raw material gas between the dielectric discharge tube 3 and the grounding electrode 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ozone generator for industrially generating ozonized gas used in water treatment facilities and the like.

Ozonized gas, which is a gas containing ozone at a predetermined concentration, has a deodorizing and sterilizing action and is used in water treatment facilities and the like. As a method for industrially generating ozonized gas, a method is generally used in which oxygen or a source gas containing oxygen is circulated in a minute space, an electric field is applied to the minute space to generate a silent discharge, and this discharge energy is generated. It is.
In the minute space that generates silent discharge, a dielectric discharge tube made of glass or the like having a high-voltage electrode inside is inserted into a ground electrode composed of a metal tube such as stainless steel. Formed between the tubes. The high voltage electrode is a thin film formed by spraying a metal such as aluminum on the inner surface of a dielectric discharge tube.
In general, since an ozone generator is highly efficient when operated at a high gas pressure, a ground electrode, a dielectric discharge tube, and the like are housed in a high-pressure tank.

The dielectric discharge tube is sealed at one end so that the source gas flows only in the discharge space and does not pass through the dielectric discharge tube. Since ozone and nitrogen oxides (referred to as ozone, etc.) generated by the discharge are often downstream in the gas flow, the downstream end should be placed so that these ozone etc. do not enter the dielectric discharge tube as much as possible. Seal.
Although the upstream side is open, ozone or the like moves upstream against the gas flow and does not enter the inside of the dielectric discharge tube from the open end on the upstream side. The electrode is not corroded by ozone or the like. Even when the operation of the ozone generator is stopped, the gas flow is stopped after holding the state in which the discharge is stopped and only the gas is allowed to flow for a predetermined period of time. Never go inside.
In some cases, the dielectric discharge tube is hermetically sealed so that the high voltage electrode is not corroded by ozone generated by the discharge field or ozone such as nitrogen oxides. (For example, see Patent Document 1)

JP-A-11-35303.

  The dielectric discharge tube whose end on the downstream side of the gas flow is closed will not corrode the high-voltage electrode if it is started and stopped according to the normal operation state and procedure as described above. However, if a sudden accident such as electrode breakage or water leakage occurs and the inside of the high-pressure tank is released to the atmosphere immediately after stopping the ozone generator for inspection or repair, moisture in the atmosphere Nitrogen oxide and water react on the surface of the high voltage electrode to produce nitric acid, and the high voltage electrode corrodes in a short time. The same applies to the case where the ozone generator is stopped without taking a predetermined procedure. The inventors have discovered these.

When the dielectric discharge tube is sealed, a pressure difference between the gas pressure and the atmospheric pressure is applied to the dielectric discharge tube. It is known that the dielectric strength decreases when a dielectric under pressure is exposed to an electric field. Moreover, the probability that the dielectric discharge tube breaks is increased from that where pressure, that is, mechanical stress is applied, and reliability is lowered.
The ozone generator according to the present invention aims to obtain an ozone generator in which gas pressure is not applied to the dielectric discharge tube so that the high-voltage electrode is not corroded even in an emergency stop or the like. It is.

  An ozone generator according to the present invention is an ozone generator that generates an ozonized gas, which is a gas containing ozone, from a source gas containing oxygen by discharge, and has a gas distribution port at one end on the side from which the source gas flows. A gas discharge plug provided and a cylindrical dielectric discharge tube sealed at the other end; a high voltage electrode provided in a cylindrical shape inside the dielectric discharge tube to which an AC voltage is applied; and the dielectric A ground electrode which is a metal cylindrical tube provided outside the body discharge tube at a predetermined interval; a high voltage power source for applying an AC voltage to the high voltage electrode; the dielectric discharge tube; the high voltage electrode; and the ground electrode. A high-pressure container capable of sealing and containing an ozonized gas, a source gas supply unit for supplying source gas flowing between the dielectric discharge tube and the ground electrode to the high-pressure container, and the high-pressure vessel Power supply and raw materials It is obtained by a controller for controlling the scan supply unit.

  Further, an ozone generator for generating an ozonized gas, which is a gas containing ozone, from a source gas containing oxygen by discharge, a cylindrical dielectric discharge tube having one end opened and the other end sealed, A high voltage electrode provided in a cylindrical shape inside the dielectric discharge tube to which an AC voltage is applied, a protective portion that covers and protects the high voltage electrode, and a predetermined interval outside the dielectric discharge tube A ground electrode that is a cylindrical metal tube, a high-voltage power source that applies an AC voltage to the high-voltage electrode, the dielectric discharge tube, the high-voltage electrode, and the ground electrode are housed, source gas is contained, and ozonized gas is contained. A sealable high-pressure vessel, a source gas supply unit that supplies a source gas flowing between the dielectric discharge tube and the ground electrode to the high-pressure vessel, and a control unit that controls the high-pressure power source and the source gas supply unit And with Than is.

  Furthermore, it is an ozone generator that generates ozonized gas, which is ozone-containing gas, from oxygen-containing source gas by discharge, and is provided with a gas distribution stopper with a gas distribution port at one end on the side where the source gas flows A cylindrical first dielectric discharge tube with the other end open, a cylindrical second dielectric discharge tube with one end open and the other end sealed, and the first dielectric discharge tube A cylindrical shape made of an insulating material that closes the open end of the second dielectric discharge tube in an airtight manner and connects the inside of the first dielectric discharge tube and the second dielectric discharge tube. A connecting member, a high-voltage electrode provided in a cylindrical shape within the first dielectric discharge tube and the second dielectric discharge tube, to which an alternating voltage is applied, the first dielectric discharge tube, Metal provided at a predetermined interval outside the second dielectric discharge tube A cylindrical ground electrode, a high-voltage power supply for applying an alternating voltage to the high-voltage electrode, the first dielectric discharge tube, the second dielectric discharge tube, the high-voltage electrode, and the ground electrode; A sealable high-pressure vessel in which source gas enters and ozonized gas exits, and source gas flowing between the first dielectric discharge tube and the second dielectric discharge tube and the ground electrode is supplied to the high-pressure vessel. A source gas supply unit, and a control unit that controls the high-voltage power source and the source gas supply unit are provided.

  An ozone generator according to the present invention is an ozone generator that generates an ozonized gas, which is a gas containing ozone, from a source gas containing oxygen by discharge, and has a gas distribution port at one end on the side from which the source gas flows. A gas discharge plug provided and a cylindrical dielectric discharge tube sealed at the other end; a high voltage electrode provided in a cylindrical shape inside the dielectric discharge tube to which an AC voltage is applied; and the dielectric A ground electrode which is a metal cylindrical tube provided outside the body discharge tube at a predetermined interval; a high voltage power source for applying an AC voltage to the high voltage electrode; the dielectric discharge tube; the high voltage electrode; and the ground electrode. A high-pressure container capable of sealing and containing an ozonized gas, a source gas supply unit for supplying source gas flowing between the dielectric discharge tube and the ground electrode to the high-pressure container, and the high-pressure vessel Power supply and raw materials Since that a control unit for controlling the scan supply unit, advantageous effect is attained that never corrode high voltage electrode even for emergency stop ozone generator.

  Further, an ozone generator for generating an ozonized gas, which is a gas containing ozone, from a source gas containing oxygen by discharge, a cylindrical dielectric discharge tube having one end opened and the other end sealed, A high voltage electrode provided in a cylindrical shape inside the dielectric discharge tube to which an AC voltage is applied, a protective portion that covers and protects the high voltage electrode, and a predetermined interval outside the dielectric discharge tube A ground electrode that is a cylindrical metal tube, a high-voltage power source that applies an AC voltage to the high-voltage electrode, the dielectric discharge tube, the high-voltage electrode, and the ground electrode are housed, source gas is contained, and ozonized gas is contained. A sealable high-pressure vessel, a source gas supply unit that supplies a source gas flowing between the dielectric discharge tube and the ground electrode to the high-pressure vessel, and a control unit that controls the high-pressure power source and the source gas supply unit And with Since it such, the effect is there that never corrode high voltage electrode even for emergency stop ozone generator.

  Furthermore, it is an ozone generator that generates ozonized gas, which is ozone-containing gas, from oxygen-containing source gas by discharge, and is provided with a gas distribution stopper with a gas distribution port at one end on the side where the source gas flows A cylindrical first dielectric discharge tube with the other end open, a cylindrical second dielectric discharge tube with one end open and the other end sealed, and the first dielectric discharge tube A cylindrical shape made of an insulating material that closes the open end of the second dielectric discharge tube in an airtight manner and connects the inside of the first dielectric discharge tube and the second dielectric discharge tube. A connecting member, a high-voltage electrode provided in a cylindrical shape within the first dielectric discharge tube and the second dielectric discharge tube, to which an alternating voltage is applied, the first dielectric discharge tube, Metal provided at a predetermined interval outside the second dielectric discharge tube A cylindrical ground electrode, a high-voltage power supply for applying an alternating voltage to the high-voltage electrode, the first dielectric discharge tube, the second dielectric discharge tube, the high-voltage electrode, and the ground electrode; A sealable high-pressure vessel in which source gas enters and ozonized gas exits, and source gas flowing between the first dielectric discharge tube and the second dielectric discharge tube and the ground electrode is supplied to the high-pressure vessel. Since the raw material gas supply unit and the control unit for controlling the high voltage power source and the raw material gas supply unit are provided, there is an effect that the high voltage electrode is not corroded even when the ozone generator is emergency stopped.

Embodiment 1 FIG.
FIG. 1 is a view for explaining the structure of an ozone generator according to Embodiment 1 of the present invention. 2 to 5 are diagrams for explaining the structure of the dielectric discharge tube. FIG. 2 is a sectional view in a section parallel to the gas flow. FIG. 3 is a sectional view in a section perpendicular to the gas flow. FIG. 4 is an arrow view of the dielectric discharge tube as viewed from the upstream side of the gas flow. FIG. 3 is a cross-sectional view taken along the line AA in FIG. 2, and FIG. The BB cross section in FIG. 3 becomes FIG.

  A set of a plurality of high-voltage electrodes 1 and ground electrodes 2 is housed in a horizontal central portion of a high-pressure tank 100 that is a high-pressure vessel. The high voltage electrode 1 is formed on the inner surface of the dielectric discharge tube 3 as a metal film having high conductivity such as aluminum or nickel. The ground electrode 2 is composed of a metal tube such as stainless steel. Both the dielectric discharge tube 3 and the ground electrode 2 have a cylindrical shape, and the dielectric discharge tube 3 and the ground electrode 2 are arranged so as to be concentric. A space formed between the dielectric discharge tube 3 and the ground electrode 2 is a discharge space 4. Spacers 4A are provided at positions close to both ends of the dielectric discharge tube 3 in order to make the discharge space 4 have a donut-shaped cross section.

  The high-pressure tank 100 has an external shape such that a cylinder is placed sideways. A predetermined number of sets of a plurality of dielectric discharge tubes 3 and ground electrodes 2 are arranged on the circular cross section at a necessary interval. At both ends of the cylindrical ground electrode 2, a flat plate 5 </ b> A having a hole in the position of the ground electrode 2 is attached so that gas passes through the ground electrode 2. The two flat plates 5A and the ground electrode 2 are combined to form a cylindrical structure 5B having an outer shape provided with a plurality of through holes (inner surfaces of the ground electrode 2) in the axial direction. The structure 5B can be sealed and filled with cooling water 6 for cooling the ground electrode 2. The cooling water 6 is supplied to and discharged from the structure 5B by the cooling water header 7 provided below the high-pressure tank 100.

  In the figure of the high-pressure tank 100, there is a raw material gas inlet 101 at the lower left, and an ozonized gas outlet 102 at the lower right. The raw material gas that has entered from the raw material gas inlet 101 passes through the discharge space 4 where silent discharge is generated, becomes ozonized gas containing ozone generated by the discharge, and is discharged from the ozonized gas outlet 102. A high voltage line inlet 103 is provided on the upper left of the high pressure tank 100 in order to introduce the high voltage wiring 9 from the high voltage power supply 8 into the high pressure tank 100. At the high voltage line inlet 103, measures are taken to sufficiently insulate the grounded high pressure tank 100 and the high voltage wiring 9 from each other and prevent gas from leaking. Each of the source gas inlet 101 and the ozonized gas outlet 102 has a valve 10 (not shown), which can adjust the pressure and flow rate of the source gas. If the two valves 10 are closed, the high-pressure tank 100 is sealed. The two valves 10 are controlled by the source gas supply unit 11. The source gas supply unit 11 also controls the flow rate and pressure of the source gas. The source gas supply unit 11 and the high voltage power source 3 are controlled by the control unit 12.

The source gas is air. Oxygen may be used. Any gas may be used as the source gas as long as it is a gas that contains oxygen, does not generate harmful substances by discharge, and is acceptable in cost.
A cylindrical dielectric discharge tube 3 made of glass or the like and sealed at one end has a power supply film, ie, a high-voltage electrode 1, on which an metal such as aluminum or nickel is deposited. The high voltage electrode 1 also has a cylindrical shape. A power supply rod 14 is connected to the high voltage electrode 1 through a power supply brush 13. The power feeding rod 14 is connected to the high voltage wiring 9 through the fuse 15. The fuse 15 immediately cuts off an excessive current when a situation occurs in which an excessive current flows between the high-voltage electrode 1 and the ground electrode 2 due to dielectric breakdown occurring in the dielectric discharge tube 3. belongs to. The fuse 15 is attached to the dielectric discharge tube 3 by a gas flow rate control plug 16 that closes the open end of the dielectric discharge tube 3. The power supply brush 13 and the power supply rod 14 are made of stainless steel resistant to corrosion, and the high voltage wiring 9 and the fuse 15 are provided with a coating resistant to corrosion. The open end of the dielectric discharge tube 3 is disposed on the side from which the source gas flows.

  The gas flow rate control plug 16 is made of a fluororesin having high corrosion resistance. The gas flow rate control plug 16 is provided with a gas flow port 17 so that a small amount of gas can flow. The inside of the high-pressure tank 100 is pressurized to about 2 atmospheres during operation. The size of the gas flow port 17 is such that the time required for the pressure inside the dielectric discharge tube 3 to become atmospheric pressure is several minutes to several tens of minutes when the pressurized dielectric discharge tube 3 is at atmospheric pressure. The size is as follows. As the dielectric discharge tube 3, a glass tube such as borosilicate glass, a ceramic tube such as alumina ceramics or titanium dioxide ceramics, a metal tube with a dielectric coated on the outer surface, or the like is used.

  Next, the operation will be described. In FIG. 5, the figure explaining the starting procedure and stopping procedure of an ozone generator is shown. FIG. 6 shows a diagram for explaining the operation when the ozone generator is brought to an emergency stop. 5 and 6 are virtual diagrams for explaining the concept of operation. 5 and 6, the discharge power amount, the gas flow rate, the gas pressure in the high-pressure tank 100, the pressure in the dielectric discharge tube 3, the upstream side (abbreviated as the vicinity of the inlet) and the downstream side (outlet) of the dielectric discharge tube 3. The time variation of the ozone concentration in the inside of the abbreviation is abbreviated. The ozone concentration has a logarithmic axis on the vertical axis. In addition, although nitrogen oxide etc. are produced | generated by discharge, since the density | concentration of nitrogen oxide etc. is substantially proportional to ozone concentration, only ozone concentration is shown.

While the ozone generator is stopped, the pressure in the high-pressure tank 100 is made higher than the atmospheric pressure to seal it so that air and moisture do not enter the high-pressure tank 100 from the outside. When starting the ozone generator, as shown in the left half of FIG. 5, first, the raw material gas is fed into the high-pressure tank 100 at a predetermined pressure (about 2 atmospheres) and a predetermined flow rate. When a predetermined time elapses and the pressure inside the dielectric discharge tube 3 becomes the same as the pressure in the high-pressure tank 100, a predetermined magnitude is set such that discharge occurs with the gap length between the high-voltage electrode 1 and the ground electrode 2. The AC voltage is applied to the high voltage electrode 1. Silent discharge occurs in the discharge space 4 and ozone is generated. The ozone concentration in the vicinity of the outlet is a predetermined value, and an ozonized gas containing ozone having a predetermined concentration is produced in a predetermined amount. Since there is a steady gas flow, the ozone generated by the discharge hardly comes near the inlet upstream of the gas flow. Therefore, the ozone concentration near the entrance is low. Furthermore, since the cross-sectional area of the gas flow port 17 is sufficiently smaller than the cross-sectional area of the dielectric discharge tube 3, the amount of gas passing through the gas flow port 17 in a state where there is no pressure difference is very small. Therefore, almost no ozone or the like enters the dielectric discharge tube 3. Therefore, the ozone concentration inside the dielectric discharge tube 3 is maintained at the value before starting discharge (the ozone concentration naturally existing in the atmosphere). The same applies to nitrogen oxides.
In addition, it expresses that it hardly enters that the quantity of ozone etc. which enter the inside of the dielectric discharge tube 3 is an allowable range (a range which does not cause corrosion).

When the ozone generator is stopped, as shown in the right half of FIG. 5, first, the application of the AC voltage to the high-voltage electrode 1 is stopped to prevent the discharge. The supply of the source gas is continued as it is until ozone and nitrogen oxides are discharged out of the high-pressure tank 100. The time for which the gas is circulated after the discharge is stopped depends on the size of the tank (capacity: V (m ³ )) and the amount of the circulated gas (Q (m ³ / s)). What is necessary is just to set several times or more longer than the time t1 (= V / Q (s)) to be replaced. It is also effective to measure the ozone concentration meter at the gas outlet and stop the gas after it reaches a sufficiently small value (for example, 0.1 ppm).
Since ozone is no longer generated when the discharge is stopped, the ozone concentration near the outlet is lowered. In a state where the ozone concentration in the vicinity of the inlet and the outlet is sufficiently lowered after a predetermined time has passed, the supply of the raw material gas into the high-pressure tank 100 is stopped, and the tank inlet / outlet valve 10 is closed. When the gas supply is stopped, the pressure in the high-pressure tank 100 is lowered by the pressure for flowing the gas, and the gas pressure is further slowly lowered. The gas pressure in the tank is always higher than atmospheric pressure. As described above, when the ozone generator is stopped in a predetermined procedure, the ozone concentration near the inlet is kept low, so that the high-pressure electrode is not provided in the conventional dielectric discharge tube with the upstream end of the gas flow open. There is no corrosion.
Furthermore, in the dielectric discharge tube 3 having the gas flow rate control plug 16, even if the pressure in the high-pressure tank 100 decreases, the pressure in the dielectric discharge tube 3 is higher than the pressure in the high-pressure tank 100 for a predetermined time. Kept high. During this time, only gas is emitted from the dielectric discharge tube 3, and ozone or the like does not enter the dielectric discharge tube 3. Further, even after the pressure becomes the same, the gas circulation port 17 is sufficiently small, so that ozone and the like hardly enter the dielectric discharge tube 3.

  When the ozone generator is stopped emergencyly and opened to the atmosphere, as shown in FIG. 6, the stop of the discharge, the stop of the gas flow, and the release to the atmosphere occur almost simultaneously. When released to the atmosphere, the pressure in the high-pressure tank 100 becomes atmospheric pressure. Since ozone generated by the discharge remains in the high-pressure tank, when the gas flow stops and is released to the atmosphere, ozone diffuses into and out of the high-pressure tank, and the ozone concentration near the inlet increases. Even if the ozone concentration near the entrance increases, the pressure inside the dielectric discharge tube 3 is kept higher than the atmospheric pressure for a predetermined time after being opened to the atmosphere, and during this time, gas is discharged from the dielectric discharge tube 3. It only exits, and ozone or the like does not enter the dielectric discharge tube 3. Since it takes several minutes to several tens of minutes for the pressure inside the dielectric discharge tube 3 to become atmospheric pressure, ozone diffuses into the atmosphere, the ozone concentration near the inlet is low, and the gas circulation port 17 is sufficiently Since it is small, ozone or the like and moisture in the atmosphere hardly enter the dielectric discharge tube 3. Even if the ozone concentration is not low, take some measures to protect the high-pressure electrode from corrosion in a few minutes to several tens of minutes until the pressure inside the dielectric discharge tube 3 reaches atmospheric pressure. Is possible.

On the other hand, in the conventional dielectric discharge tube, the internal pressure and ozone concentration are the same as the vicinity of the inlet. For this reason, as soon as it is opened to the atmosphere, the internal pressure drops to atmospheric pressure, and ozone, nitrogen oxides and moisture in the atmosphere diffuse into the dielectric discharge tube as well as outside. As a result, the high voltage electrode is corroded by nitric acid generated from nitrogen oxides and water.
The pressure difference between the inside and the outside of the dielectric discharge tube 3 is generated only for a predetermined time after the internal pressure of the high-pressure tank 100 is changed, and the pressure is not applied to the dielectric discharge tube 3 at all times. Further, the dielectric discharge tube 3 is not discharged during the time when pressure is applied. For this reason, its reliability is much higher than that of a sealed dielectric discharge tube.

The gas flow rate control plug 16 has the same effect even when an insulator such as Viton, EPD rubber, or silicon is used. Further, a metal material such as stainless steel, iron, aluminum, or the like may be used. Any material may be used as long as it has sufficient corrosion resistance and does not adversely affect the discharge.
Although the gas flow rate control plug 16 has a role of fixing the fuse 15 to the dielectric discharge tube 3, it is not always necessary to do so. Although a tube with one end closed is used, a tube open at both ends may be used to plug both ends. When plugging both ends, vents are provided in the plug on the upstream side of the gas flow, and vents are not provided in the downstream line.
Although the high-voltage electrode is a metal film deposited on the inner surface of the dielectric discharge tube, a cylindrical metal having conductivity may be inserted into the dielectric discharge tube. The high-voltage electrode and the ground electrode may be arranged in any manner as long as the high-voltage electrode and the ground electrode are concentrically arranged, and the distance between the high-voltage electrode and the ground electrode can be appropriately and evenly spaced to generate discharge.
The above also applies to other embodiments.

Embodiment 2. FIG.
In the second embodiment, the structure of the dielectric discharge tube is changed to one having plugs at both ends. FIG. 7 shows a cross-sectional view in a cross section parallel to the gas flow for explaining the structure of the dielectric discharge tube included in the ozone generator according to Embodiment 2 of the present invention. The overall structure is the same as in the first embodiment.

  Only the differences from the first embodiment will be described. Both ends of the dielectric discharge tube 3A are open, and a gas sealing plug 18 is provided at the downstream end. The gas sealing plug 18 completely shuts off the gas flow. Note that the same gas flow rate control plug 16 as in the first embodiment is used on the upstream side.

  The ozone generator according to the second embodiment operates in the same manner as in the first embodiment and has the same effect.

Embodiment 3 FIG.
In the third embodiment, the structure of the plug on the upstream side of the dielectric discharge tube of the second embodiment is further changed. FIG. 8 shows a sectional view in a section parallel to the gas flow for explaining the structure of the dielectric discharge tube included in the ozone generator according to Embodiment 3 of the present invention. The overall structure is the same as in the first embodiment.

  Only the differences from the second embodiment will be described. The gas flow control plug 16A fixes the power supply rod 14A, not the fuse 15, to the dielectric discharge tube 3A. In FIG. 8, the fuse 15 is disposed near the dielectric discharge tube 3A. However, the gas flow rate control plug 16A is also used when the fuse is installed away from the dielectric discharge tube or when the fuse is not provided. Can be used.

  The ozone generator according to the third embodiment operates in the same manner as in the first embodiment and has the same effect.

Embodiment 4 FIG.
In the fourth embodiment, two dielectric discharge tubes are arranged in series in one ground electrode, and the gas flow plug is closed while a voltage is applied to the high voltage electrode. FIG. 9 shows a cross-sectional view in a cross section parallel to the gas flow for explaining the structure of the dielectric discharge tube included in the ozone generator according to Embodiment 4 of the present invention.

  The reason for using two dielectric discharge tubes will be described. Since the amount of ozone generated is proportional to the surface area of the discharge electrode (dielectric discharge tube), when increasing the amount of ozone generated, the number of dielectric discharge tubes can be increased or the length of the dielectric discharge tube can be increased. Good. If the diameter of the high-pressure tank is increased, inconvenience occurs in maintenance and the like. Therefore, the diameter of the high-pressure tank has an appropriate size, and the number of dielectric discharge tubes also has an appropriate number. Increasing the length of the dielectric discharge tube also has an upper limit in cost. The dielectric discharge tube needs to satisfy a predetermined accuracy with respect to the outer diameter, inner diameter, roundness, linearity, and the like. Since the cost for obtaining a predetermined accuracy increases as the length increases, there is an upper limit to the length of the dielectric discharge tube that can be manufactured at an acceptable cost. As shown in FIG. 9, when two dielectric discharge tubes are arranged in one ground electrode, the unit ozone is larger than the case where two sets of one dielectric discharge tube are provided in one ground electrode. Manufacturing costs such as a high-pressure tank and a ground electrode per generation amount are reduced, and an ozone generator can be manufactured at a low cost.

  In FIG. 9, it is assumed that gas flows from left to right in the figure. The left side in the figure is called the upstream side, and the right side is called the downstream side. Both ends of the upstream dielectric discharge tube 3B are open, and a gas flow rate control plug 16B capable of opening and closing the gas flow port 17 is provided on the upstream side, and a gas sealing plug 18 is provided on the downstream side. The downstream side dielectric discharge tube 3C is open at both ends, and is provided with a gas flow rate control plug 16C capable of opening and closing the gas flow port 17 on the upstream side, and with a gas sealing plug 18A on the downstream side. The dielectric discharge tube 3 </ b> B and the dielectric discharge tube 3 </ b> C are inserted so that the side to which the high voltage wiring 9 is connected becomes both ends of the ground electrode 2 so that a high voltage can be applied to the high voltage electrode 1. Therefore, the gas flow control plug 16B and the gas sealing plug 18A also serve to attach the fuse 15 to the dielectric discharge tube 3B or the dielectric discharge tube 3C while maintaining airtightness.

  The gas flow rate control plug 16B and the gas flow rate control plug 16C close the gas flow port 17 while the voltage is applied to the high-voltage electrode 1 so as not to pass the gas, and when the voltage is not applied, the predetermined flow rate is applied. The gas is passed through. In the case of passing the gas, as in the first embodiment, the gas flow is such that the gas pressure during operation becomes atmospheric pressure in a predetermined time of several minutes to several tens of minutes.

  Next, the operation will be described. FIG. 10 is a diagram for explaining the operation of the ozone generator according to Embodiment 5 of the present invention. In FIG. 10, the discharge power amount, the gas flow rate control plug 16B and the gas flow rate control plug 16C are opened or closed, the gas flow rate, the gas pressure in the high pressure tank 100, the pressure in the dielectric discharge tube 3, the high pressure tank The time change is shown about the ozone density | concentration inside each part in 100, and dielectric discharge tube 3B, 3C. The ozone concentration of each part in the high-pressure tank 100 is determined between the upstream side of the dielectric discharge tube 3B on the upstream side (referred to as the vicinity of the inlet) and between the two dielectric discharge tubes 3B and 3C (referred to as the vicinity of the middle). Three points on the downstream side (referred to as the vicinity of the outlet) of the downstream dielectric discharge tube 3C will be described. For comparison, the ozone concentration inside the dielectric discharge tube 3C on the downstream side when the gas flow port 17 is always open is indicated by a broken line.

  When starting the ozone generator according to the fifth embodiment, as shown in the left half of FIG. 10, first, the raw material gas is fed into the high-pressure tank 100 at a predetermined pressure and a predetermined flow rate. No voltage is applied to the high voltage electrode, and the gas flow port 17 of the gas flow rate control plug 16B and the gas flow rate control plug 16C is open, and the pressure inside the dielectric discharge tubes 3B and 3C gradually increases. The pressure inside the dielectric discharge tubes 3B and 3C is the same on the upstream side and the downstream side. When a predetermined time has passed and the pressure inside the dielectric discharge tubes 3B and 3C becomes the same as the pressure in the high-pressure tank 100, a predetermined discharge is generated with the gap length between the high-voltage electrode 1 and the ground electrode 2 An AC voltage of the magnitude is applied to the high-voltage electrode 1. When the voltage is applied, the gas flow port 17 of the gas flow rate control plug 16B and the gas flow rate control plug 16C are closed. When a voltage is applied, a silent discharge is generated in the discharge space 4 and an ozonized gas containing ozone having a predetermined concentration is produced in a predetermined amount. The ozone concentration near the outlet is a predetermined value, and the gas concentration near the middle is approximately half that near the outlet. Since there is a steady gas flow, the ozone generated by the discharge hardly comes near the inlet upstream of the gas flow. Therefore, the ozone concentration near the entrance is low.

When a voltage is applied to the high-voltage electrode and the discharge starts, the gas flow port 17 is closed. Therefore, ozone or the like does not enter the dielectric discharge tube 3C on the downstream side, and the inside of the dielectric discharge tubes 3B and 3C does not enter. The ozone concentration is kept at the same ozone concentration as the source gas. This effect by closing the gas flow port when a voltage is applied to the high-voltage electrode is the same even when one dielectric discharge tube is arranged in the ground electrode.
When the gas flow rate control plug 16B and the gas flow rate control port 16C of the gas flow rate control plug 16C are always open, as shown by the broken line in FIG. 10, the dielectric discharge on the downstream side during the operation of the ozone generator. There is a possibility that the ozone concentration inside the tube 3C gradually increases and the high voltage electrode 1 is corroded. If the gas circulation port 17 is closed during the generation of discharge, the ozone concentration inside the dielectric discharge tube 3C on the downstream side will not increase during the operation of the ozone generator, and the high voltage electrode 1 will not corrode. .

  When the ozone generator is stopped, as shown in the right half of FIG. 10, first, the application of the AC voltage to the high-voltage electrode 1 is stopped to prevent the discharge. When no AC voltage is applied to the high voltage electrode 1, the gas flow rate control plug 16B and the gas flow port 17 of the gas flow rate control plug 16C are opened. The supply of the raw material gas is continued as it is. When the discharge is stopped, ozone and the like are not generated, so the ozone concentration near the middle and near the outlet is greatly reduced in a short time. Although the gas flow port 17 is open, the gas flow port 17 is small, the time until the ozone concentration near the middle decreases is short, and there is no pressure difference inside and outside the dielectric discharge tubes 3B and 3C. Even in the dielectric discharge tube 3C, ozone and the like hardly enter the dielectric discharge tubes 3B and 3C. The upstream dielectric discharge tube 3B has a low ozone concentration in the vicinity of the entrance, so that ozone and the like hardly enter the dielectric discharge tube 3B.

  In a state where the ozone concentration in the vicinity of the middle and the outlet is sufficiently lowered after a predetermined time has passed, the feed of the source gas into the high pressure tank 100 is stopped, the gas valve is closed, and the high pressure tank 100 is sealed. When the supply of the source gas is stopped, the pressure in the high-pressure tank 100 is reduced by the pressure applied to generate the gas flow. The pressure inside the dielectric discharge tubes 3B and 3C higher than the atmospheric pressure gradually decreases and becomes the same as the pressure in the high-pressure tank 100 after a predetermined time. Even at this stage, ozone or the like does not enter the dielectric discharge tubes 3B and 3C.

  When the ozone generator is stopped emergencyly and opened to the atmosphere, as shown in FIG. 11, the stop of voltage application, the stop of gas flow, and the release to the atmosphere occur almost simultaneously. When no voltage is applied, the gas flow port 17 of the gas flow rate control plug 16B and the gas flow rate control plug 16C is opened. The pressure inside the dielectric discharge tubes 3B and 3C is higher than the atmospheric pressure, and during a predetermined time of several minutes to several tens of minutes, gas is discharged from the inside of the dielectric discharge tubes 3B and 3C, and ozone and the like The moisture inside does not enter the dielectric discharge tubes 3B and 3C. This is the same as the operation in the case of the first embodiment.

If the gas flow port 17 is opened when no voltage is applied to the high-voltage electrode 1, it is a very short time from when no voltage is applied to the high-voltage electrode 1 until the concentration of ozone or the like in the middle decreases. If the ozone or the like enters into the inside of the dielectric discharge tube 3C on the downstream side from the open gas flow port 17, and the number of times of starting and stopping the ozone generator becomes very large, the high voltage electrode may be corroded. A measure for further reducing this possibility will be described.
If the gas circulation port 17 is opened after a predetermined time has elapsed until no voltage is applied to the high-voltage electrode and ozone is discharged from the high-pressure tank, the gas circulation port is maintained in a state where ozone or the like remains in the high-pressure tank. Is closed, so that ozone or the like can be almost completely prevented from entering the dielectric discharge tubes 3B and 3C. If the gas pressure is slightly lower than when applying a voltage when applying a gas flow without applying a voltage to the high-voltage electrode, no voltage will be applied to the high-voltage electrode and the gas flow port will open. For a while, gas is emitted from the inside of the dielectric discharge tubes 3B and 3C, so that ozone or the like does not enter the inside of the dielectric discharge tubes 3B and 3C.
Even if these countermeasures are applied when a single dielectric discharge tube is arranged in the ground electrode, the same effect can be obtained.

Embodiment 5. FIG.
The fifth embodiment is a case where the high voltage electrode on the inner surface of the dielectric discharge tube is covered with a protective material having ozone resistance and nitrogen oxide resistance. FIG. 12 is a sectional view in a section parallel to the gas flow for explaining the structure of the dielectric discharge tube included in the ozone generator according to Embodiment 5 of the present invention. The overall structure is the same as in the first embodiment.
The high voltage electrode 1 is coated with the same kind of glass 19 as the dielectric discharge tube 3. Since the high-voltage electrode 1 is covered and coated with a very stable glass 19, there is no concern about corrosion. Further, since only one of the dielectric discharge tubes is sealed, no pressure is applied to the dielectric discharge tube. The glass 19 is a protective part that covers and protects the high-voltage electrode 1.

The ozone generator according to the fifth embodiment operates in the same manner as in the first embodiment and has the same effect. In addition, since the high voltage electrode is protected by the protection part, even if the open end of the dielectric discharge tube is directed downstream of the flow of the raw material gas, the high voltage electrode is not corroded by ozone or the like.
In this embodiment, the case of glass coating is shown, but the same effect can be obtained by coating by spraying ceramic such as alumina. Further, it may be coated with other ceramics or insulating materials. By coating the high voltage electrode with an insulating material in this way, the high voltage electrode can be protected from nitric acid and ozone generated from nitrogen oxides, and at the same time, creeping discharge that is likely to occur at the end of the high voltage electrode 1 Can also be suppressed, which is effective.

Embodiment 6 FIG.
The sixth embodiment is a case where the fourth embodiment is changed so that two discharge dielectric tubes are connected by a pipe-shaped connecting member. FIG. 13 shows a cross-sectional view in a cross section parallel to the gas flow for explaining the structure of the dielectric discharge tube included in the ozone generator according to Embodiment 6 of the present invention.

Only differences from FIG. 9 which is the case of the fourth embodiment will be described. The upstream side is the first dielectric discharge tube, and the downstream side is the second dielectric discharge tube. The downstream end of the upstream dielectric discharge tube 3D and the upstream end of the downstream dielectric discharge tube 3E are open, and a connecting member 20 that is a cylindrical tube is connected between them. The connecting member 20 is made of the same material as the gas flow rate control plug such as a fluororesin having high corrosion resistance. In addition, if the corrosion resistance is high, a material different from the gas flow rate control plug may be used.
The connecting member 20 serves as a plug with respect to the open ends of the dielectric discharge tubes 3D and 3E on both sides, and airtightness is maintained between the dielectric discharge tube 3D and the dielectric discharge tube 3E and the connecting member 20. The connecting member 20 communicates the internal space of the upstream dielectric discharge tube 3D and the downstream dielectric discharge tube 3E. At the upstream end of the upstream dielectric discharge tube 3D, a gas flow plug 16 similar to that of the first embodiment is provided. The downstream end of the downstream dielectric discharge tube 3E is sealed with a gas sealing plug 18A. With the above configuration, the two dielectric discharge tubes 3D and 3E function in the same manner as one long dielectric discharge tube.

  The ozone generator according to the sixth embodiment operates in the same manner as in the first embodiment and has the same effects. By connecting two dielectric discharge tubes with a connecting member, the length of the discharge space can be made longer than in the case of a single dielectric discharge tube, and the manufacturing costs of high-pressure tanks and ground electrodes per unit ozone generation amount are increased. The ozone generator can be manufactured at low cost.

It is a figure explaining the structure of the ozone generator which concerns on Embodiment 1 of this invention. It is sectional drawing in the cross section parallel to the flow of gas explaining the structure of the dielectric discharge tube which the ozone generator which concerns on Embodiment 1 of this invention has. It is sectional drawing in a cross section perpendicular | vertical to the gas flow explaining the structure of the dielectric discharge tube which the ozone generator which concerns on Embodiment 1 of this invention has. It is the arrow line view seen from the upstream of the gas flow explaining the structure of the dielectric discharge tube which the ozone generator which concerns on Embodiment 1 of this invention has. It is a figure explaining the starting procedure and stop procedure of an ozone generator. It is a figure explaining operation | movement at the time of the emergency stop of the ozone generator which concerns on Embodiment 1 of this invention. It is sectional drawing in a cross section parallel to the flow of gas explaining the structure of the dielectric discharge tube which the ozone generator which concerns on Embodiment 2 of this invention has. It is sectional drawing in a cross section parallel to the flow of gas explaining the structure of the dielectric discharge tube which the ozone generator which concerns on Embodiment 3 of this invention has. It is sectional drawing in a cross section parallel to the flow of gas explaining the structure of the dielectric discharge tube which the ozone generator which concerns on Embodiment 4 of this invention has. It is a figure explaining operation | movement of the ozone generator which concerns on Embodiment 4 of this invention. It is a figure explaining operation | movement at the time of the emergency stop of the ozone generator which concerns on Embodiment 4 of this invention. It is sectional drawing in a cross section parallel to the gas flow explaining the structure of the dielectric discharge tube which the ozone generator which concerns on Embodiment 5 of this invention has. It is sectional drawing in a cross section parallel to the flow of gas explaining the structure of the dielectric discharge tube which the ozone generator which concerns on Embodiment 6 of this invention has.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100: High pressure tank 101: Source gas inlet 102: Ozonized gas outlet 103: High voltage wire inlet 1: High voltage electrode 2: Ground electrode 3: Dielectric discharge tube 3A: Dielectric discharge tube 3B: Dielectric discharge tube 3C: Dielectric discharge tube 3D: Dielectric discharge tube 3E: Dielectric discharge tube 4: Discharge space 4A: Spacer 5A: Flat plate 5B: Structure 6: Cooling water 7: Header for cooling water 8: High-voltage power supply 9: High-voltage wiring 10: Valve 11: Source gas supply unit 12: Control unit 13: Power supply brush 14: Power supply rod 14A: Power supply rod 15: Fuse
16: Gas flow control plug 16A: Gas flow control plug 16B: Gas flow control plug 16C: Gas flow control plug 17: Gas flow port 18: Gas seal plug 18A: Gas seal plug 19: Glass (protection part)
20: Connecting member

Claims (8)

An ozone generator that generates, by discharge, an ozonized gas that is a gas containing ozone from a source gas containing oxygen,
A gas flow plug with a gas flow port provided at one end on the side where the source gas flows, and a cylindrical dielectric discharge tube sealed at the other end,
A high-voltage electrode provided in a cylindrical shape inside the dielectric discharge tube to which an alternating voltage is applied;
A ground electrode which is a metal cylindrical tube provided at a predetermined interval outside the dielectric discharge tube;
A high voltage power source for applying an AC voltage to the high voltage electrode;
Containing the dielectric discharge tube, the high-voltage electrode and the ground electrode, and a sealable high-pressure vessel in which a raw material gas enters and an ozonized gas exits;
A source gas supply unit for supplying source gas flowing between the dielectric discharge tube and the ground electrode to the high pressure vessel;
The ozone generator provided with the control part which controls the said high voltage | pressure power supply and the said source gas supply part. The ozone generator according to claim 1, wherein the two dielectric discharge tubes are arranged in series inside one ground electrode. The ozone generator according to claim 1 or 2, wherein the gas circulation port is closed when an AC voltage is applied to the high-voltage electrode. The ozone generator according to claim 3, wherein the gas circulation port is also closed for a predetermined time after an AC voltage is no longer applied to the high-voltage electrode. The raw material so that the control unit makes the gas pressure in the high-pressure vessel smaller than when the AC voltage is applied to the high-voltage electrode at a predetermined time after the AC voltage is no longer applied to the high-voltage electrode. The ozone generator according to claim 3, wherein the gas supply unit is controlled. When the control unit stops the ozone generator, the high-voltage power supply stops applying an alternating voltage to the high-voltage electrode, and then the source gas supply unit stops supplying the source gas after a predetermined time. It controls so that it may carry out, The ozone generator in any one of Claims 1-5 characterized by the above-mentioned. An ozone generator that generates, by discharge, an ozonized gas that is a gas containing ozone from a source gas containing oxygen,
A cylindrical dielectric discharge tube with one end open and the other end sealed;
A high-voltage electrode provided in a cylindrical shape inside the dielectric discharge tube to which an alternating voltage is applied;
A protective part for covering and protecting the high-voltage electrode;
A ground electrode which is a metal cylindrical tube provided at a predetermined interval outside the dielectric discharge tube;
A high voltage power source for applying an AC voltage to the high voltage electrode;
The dielectric discharge tube, the high-pressure electrode and the ground electrode are housed, a source gas enters, and a sealable high-pressure container from which ozonized gas exits,
A source gas supply unit for supplying source gas flowing between the dielectric discharge tube and the ground electrode to the high pressure vessel;
The ozone generator provided with the control part which controls the said high voltage | pressure power supply and the said source gas supply part. An ozone generator that generates, by discharge, an ozonized gas that is a gas containing ozone from a source gas containing oxygen,
A gas flow plug provided with a gas flow port at one end on the side where the source gas flows, and a cylindrical first dielectric discharge tube with the other end opened,
A cylindrical second dielectric discharge tube with one end open and the other end sealed;
The open end of the first dielectric discharge tube and the open end of the second dielectric discharge tube are closed in an airtight manner, and the inside of the first dielectric discharge tube and the second dielectric discharge tube is sealed. A cylindrical connecting member made of an insulating material to be communicated;
A high-voltage electrode provided in a cylindrical shape inside the first dielectric discharge tube and the second dielectric discharge tube and to which an alternating voltage is applied;
A ground electrode which is a metal cylindrical tube provided at a predetermined interval outside the first dielectric discharge tube and the second dielectric discharge tube;
A high voltage power source for applying an AC voltage to the high voltage electrode;
Containing the first dielectric discharge tube, the second dielectric discharge tube, the high-voltage electrode and the ground electrode, and a sealable high-pressure vessel in which a raw material gas enters and an ozonized gas exits;
A source gas supply unit for supplying source gas flowing between the first dielectric discharge tube and the second dielectric discharge tube and the ground electrode to the high pressure vessel;
The ozone generator provided with the control part which controls the said high voltage | pressure power supply and the said source gas supply part.

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