Embodiments of the present invention relate to an ozone generator.
In a discharge type ozone generator, it is important to enhance efficiency in cooling a discharge space for improving efficiency in generating ozone, and prevent pyrolysis of generated ozone.
Patent Literature 1: Japanese Patent Application Laid-open No. 2012-206898
In the discharge type ozone generator described above, the discharge space is cooled from a grounding electrode side, but there is a demand for cooling the discharge space also from a high-voltage electrode side to prevent pyrolysis of the generated ozone, and further improving efficiency in generating ozone.
An ozone generator according to an embodiment includes a container, a first metal electrode, a dielectric electrode, a heat pipe, a heat sink, and a power supply unit. A material gas is caused to flow into the container. The first metal electrode is a cylindrical electrode the axial direction of which is a first direction, and disposed in the container. A cooling medium is supplied to an outer peripheral surface thereof. The dielectric electrode is a cylindrical electrode that is disposed to be opposed to an inner peripheral surface of the first metal electrode, and is coaxial with the first metal electrode. The heat pipe is disposed to be opposed to an inner peripheral surface of the dielectric electrode, and has electrical conductivity. The heat sink is disposed on the outside as an outer space of a space between the first metal electrode and the heat pipe, and connected to the heat pipe. The power supply unit applies voltage to the heat pipe to cause electric discharge in the material gas in at least one of a first gap and a second gap to generate ozone by the electric discharge, the first gap being a gap into which the material gas is caused to flow between the first metal electrode and the dielectric electrode, the second gap being a gap into which the material gas is caused to flow between the dielectric electrode and the heat pipe.
The following describes an ozone generator according to embodiments with reference to the attached drawings.
The metal electrode 13 (an example of a first metal electrode) is a cylindrical electrode the axial direction of which is the first direction d1 as illustrated in
As illustrated in
As illustrated in
The heat sink 16 is disposed on the outside of the dielectric electrode 14. Specifically, the heat sink 16 is disposed on the outside, that is, an outer space of a space between the metal electrode 13 and the heat pipe 15. In other words, the heat sink 16 is disposed on the outside of the first discharge gap I1 and a second discharge gap I2 (described later). The heat sink 16 is connected to the heat pipe 15. Due to this, the gas in the first discharge gap I1 can be cooled by both of the heat pipe 15 and the cooling water supplied to the outer peripheral surface of the metal electrode 13, so that pyrolysis of ozone due to heat generated in the first discharge gap I1 can be prevented, and efficiency in generating ozone can be enhanced. In the present embodiment, the heat sink 16 is a fin disposed on an outer peripheral surface of the heat pipe 15 in a pinholder shape, a bellows shape, a plate shape, and the like. When the heat sink 16 is cooled by air cooling, oil cooling, and the like, the heat generated by the gas in the first discharge gap I1 is radiated by the heat sink 16 via the heat pipe 15.
The ozone generator main body 11 has a function of interrupting a current flow into the heat pipe 15, and interrupting a current flow into the dielectric electrode 14 at the time when the dielectric electrode 14 is in an anomaly state and the like (for example, a fuse 17). The fuse 17 is disposed between the heat pipe 15 and a power supply C. The power supply C (an example of a power supply unit) applies voltage to the heat pipe 15 to discharge electricity in the material gas in the first discharge gap I1 (hereinafter, referred to as dielectric barrier discharge), and generates ozone by the dielectric barrier discharge.
In the present embodiment, the storage container 12 includes a space 22 on a gas inlet side and a space 23 on a gas outlet side. The space 22 on the gas inlet side and the space 23 on the gas outlet side are connected to each other (communicate with each other) via the first discharge gap I1. The storage container 12 also includes a gas inflow port 24 for causing the material gas to flow into the storage container 12. The storage container 22 includes an ozone gas ejection port 25 for ejecting the gas (hereinafter, referred to as an ozone gas) that has flowed into the space 23 on the gas outlet side to the outside. The storage container 12 also includes a cooling water inflow port 26 for causing cooling water to flow into a closed space 21 of the metal electrode 13, and a cooling water ejection port 27 for ejecting, to the outside, high-temperature cooling water that has heat-exchanged with the metal electrode 13. The closed space 21 is a space disposed on the outer peripheral surface side of the metal electrode 13, and filled with the cooling water.
Next, the following describes a procedure of processing of generating ozone performed by the ozone generator according to the present embodiment. First, the material gas that has flowed into the space 22 on the gas inlet side flows into the first discharge gap Subsequently, voltage (for example, AC voltage) is applied to the heat pipe 15 from the power supply C, and dielectric barrier discharge is caused in the material gas that has flowed into the first discharge gap I1. Due to this, an oxygen molecule contained in the material gas that has flowed into the first discharge gap I1 is dissociated into an oxygen atom, another oxygen atom is connected thereto to ozonize the material gas, and the ozone gas is generated. Thereafter, the generated ozone gas flows out to the space 23 on the gas outlet side, and is ejected to the outside through the ozone gas ejection port 25.
To remove the heat that is generated in the discharge gap I1 due to the dielectric barrier discharge, cooling water is caused to flow into the closed space 21 from the outside via the cooling water inflow port 26. Due to this, heat is exchanged between the metal electrode 13 and the cooling water, and the inside of the discharge gap is cooled. Thereafter, the cooling water the temperature of which is raised due to heat exchange is ejected to the outside via the cooling water ejection port 27.
Additionally, in a case in which an anomaly appears in the heat pipe 15 due to a dielectric breakdown and the like, the fuse 17 disposed between the heat pipe 15 and the power supply C is blown out by a short-circuit current flowing in the heat pipe 15 in which the anomaly appears, and the heat pipe 15 is disconnected from the other heat pipe 15. Accordingly, an electric charge charged in the first discharge gap I1 between the normal heat pipe 15 and the metal electrode 13 can be prevented from flowing into the heat pipe 15 in which an anomaly appears, so that, even when an anomaly appears in some of the heat pipes 15, ozone can be continuously generated by causing dielectric barrier discharge between the normal heat pipe 15 and the metal electrode 13. In the present embodiment, the ozone generator main body 11 includes the fuse 17, but does not necessarily include the fuse 17 in a case of having a function similar to that of the fuse 17 or a case in which there is no need.
As described above, the ozone generator having the configuration described above uses the heat pipe 15 as a high-voltage electrode, applies voltage to the heat pipe 15, and causes dielectric barrier discharge in the material gas in the first discharge gap I1 between the metal electrode 13 and the dielectric electrode 14 to generate ozone by the dielectric barrier discharge. At this point, the heat pipe 15 enhances movement efficiency of the heat generated in the gas in the first discharge gap I1, and the gas in the first discharge gap I1 is cooled (air-cooled) also with the heat pipe 15.
Accordingly, the material gas in the first discharge gap I1 is cooled by both of the heat pipe 15 and the cooling water supplied to the outer peripheral surface of the metal electrode 13, and a temperature rise of the gas in the first discharge gap I1 can be suppressed, so that efficiency in generating ozone in the first discharge gap I1 can be enhanced. The cooling water is not used for cooling the gas in the first discharge gap I1 by the heat pipe 15. Thus, it is not required to newly dispose members such as a gasket, a tube, and piping for causing the cooling water to flow into the inner part of the high-voltage electrode of the ozone generator in the related art, so that the structure of the ozone generator can be prevented from being complicated. Additionally, the number of points at which the cooling water for cooling the gas in the first discharge gap I1 is caused to flow is reduced, so that a risk of leakage of the cooling water in the ozone generator can be reduced, and the weight of the ozone generator can be reduced.
In a case of disposing the heat sink 16 in the storage container 12 and cooling the heat sink 16 with the material gas, the heat sink 16 is preferably disposed at a position at which the temperature of the material gas is lower within the storage container 12. Thus, in the present embodiment, the heat sink 16 is disposed in the vicinity of a position at which the material gas is caused to flow into the storage container 12. For example, the heat sink 16 is disposed in the space 22 on the gas inlet side, and in the vicinity of the gas inflow port 24. Due to this, the heat sink 16 can be cooled with the material gas having a lower temperature, so that efficiency in cooling the gas in the first discharge gap I1 by the heat pipe 15 can be further enhanced, and efficiency in generating ozone in the first discharge gap I1 can be enhanced. The heat sink 16 is disposed in the vicinity of the gas inflow port 24 in the present embodiment, but it is sufficient that the heat sink 16 is disposed on an upstream side of the first discharge gap I1 in an inflow direction Dl of the material gas.
To further enhance efficiency in cooling the gas in the first discharge gap I1 with the heat pipe 15 and the heat sink 16, the ozone generator may be configured such that a stirring unit such as a fan is disposed in the space 22 on the gas inlet side (for example, in the vicinity of the gas inflow port 24) to stir the material gas in the storage container 12 to enable heat to be easily radiated from the heat sink 16. Due to this, the heat sink 16 can be cooled with the material gas having a lower temperature, so that efficiency in cooling the gas in the first discharge gap I1 by the heat pipe 15 can be further enhanced, and efficiency in generating ozone in the first discharge gap I1 can be enhanced.
In this way, with the ozone generator according to the first embodiment, the material gas in the first discharge gap I1 is cooled by both of the heat pipe 15 and the cooling water supplied to the metal electrode 13, and a temperature rise of the gas in the first discharge gap I1 can be suppressed, so that efficiency in generating ozone in the first discharge gap I1 can be enhanced.
The present embodiment is an example of causing dielectric barrier discharge in the material gas in the second discharge gap into which the material gas is caused to flow between the dielectric electrode and the heat pipe. In the following description, description about the same points as the first embodiment will not be repeated.
Similarly to the first embodiment, the ozone generator uses the heat pipe 15 as a high-voltage electrode, applies voltage to the heat pipe 15 to cause dielectric barrier discharge in the material gas in the second discharge gap I2 between the dielectric electrode 14 and the heat pipe 15, and generates ozone by the dielectric barrier discharge. In this case, the heat pipe 15 enhances movement efficiency of heat generated by the gas in the second discharge gap I2, and the gas in the second discharge gap I2 is cooled (air-cooled) also with the heat pipe 15.
Accordingly, with the ozone generator according to the second embodiment, a working effect similar to that of the first embodiment can be obtained.
In the present embodiment, to enhance efficiency in cooling the gas in the second discharge gap I2, a spiral-shaped groove is disposed on the outer peripheral surface of the heat pipe 15 in the first direction d1 to generate a swirl flow of the material gas in the second discharge gap I2. Due to this, the gas in the second discharge gap I2 is caused to flow from the space 22 on the gas inlet side toward the space 23 on the gas outlet side while being stirred, so that the gas in the second discharge gap I2 can be cooled more uniformly.
The present embodiment is an example of causing dielectric barrier discharge in the material gas in both of the first discharge gap into which the material gas is caused to flow between the metal electrode and the dielectric electrode and the second discharge gap into which the material gas is caused to flow between the dielectric electrode and the heat pipe. In the following description, description about the same points as the embodiments described above will not be repeated.
Similarly to the first and the second embodiments, the ozone generator uses the heat pipe 15 as the high-voltage electrode, applies voltage to the heat pipe 15 to cause dielectric barrier discharge in the material gas in the first discharge gap I1 between the metal electrode 13 and the dielectric electrode 14 and in the second discharge gap I2 between the dielectric electrode 14 and the heat pipe 15, and generates ozone by the dielectric barrier discharge. In this case, the heat pipe 15 enhances movement efficiency of heat generated by the gas in the second discharge gap I2, and the gas in the second discharge gap I2 is cooled (air-cooled) also with the heat pipe 15.
Accordingly, with the ozone generator according to the third embodiment, a working effect similar to that of the first embodiment can be obtained.
Also in the present embodiment, to enhance efficiency in cooling the gas in the second discharge gap 12, a spiral-shaped groove is disposed on the outer peripheral surface of the heat pipe 15 in the first direction d1 to generate a swirl flow of the gas in the second discharge gap I2. Due to this, the gas in the second discharge gap I2 is caused to flow from the space 22 on the gas inlet side toward the space 23 on the gas outlet side while being stirred, so that the gas in the second discharge gap I2 can be cooled more uniformly.
The present embodiment is an example of causing dielectric barrier discharge in the material gas in both of the first discharge gap and the second discharge gap, and including a flow channel for the material gas that passes through the first discharge gap after passing through the second discharge gap. In the following description, description about the same points as the third embodiment will not be repeated.
In the ozone generator, a chiller is often used for circulating the cooling water to be supplied to the closed space 21. In such a case, the temperature of the cooling water in the closed space 21 becomes lower than the temperature of the material gas. Thus, the temperature of the gas in the second discharge gap I2 becomes higher than the temperature of the material gas in the first discharge gap I1. Due to this, in a case in which the ozone generator includes a flow channel (parallel flow channel) for the material gas that passes through only one of the first discharge gap I1 and the second discharge gap I2, efficiency in generating the ozone gas in the second discharge gap I2 is decreased. Thus, in the present embodiment, a serial flow channel is formed for the material gas that passes through the first discharge gap I1 after passing through the second discharge gap I2.
Accordingly, with the ozone generator according to the fourth embodiment, even when ozone cannot be sufficiently generated in the second discharge gap I2 in which the temperature of the material gas easily rises, ozone is generated again in the first discharge gap I1 having a high effect of cooling the material gas, so that efficiency in generating the ozone gas can be enhanced.
The present embodiment is an example in which a plurality of heat pipes are arranged in parallel in the first direction to be opposed to the inner peripheral surface of one dielectric electrode. In the following description, description about the same points as the third embodiment will not be repeated.
Accordingly, with the ozone generator according to the fifth embodiment, a discharge area in a longitudinal direction of the heat pipe 15 disposed in the dielectric electrode 14 can be prolonged, so that a diameter of the storage container 12 can be reduced.
The present modification is an example in which the heat sink is disposed on the upstream side of the metal electrode in the inflow direction of the material gas, and a diameter of the gas inflow port is smaller than a diameter of the ozone gas ejection port. In the following description, description about the same configuration as that in the embodiments described above will not be repeated.
As illustrated in
The present modification is an example in which a cylindrical metal electrode (hereinafter, referred to as a normal metal electrode) coaxial with the dielectric electrode is disposed, in place of the heat pipe, to be opposed to the inner peripheral surfaces of some of the dielectric electrodes in the storage container, and the flow speed of the material gas flowing into the first discharge gap and the second discharge gap is higher than the flow speed of the material gas flowing into a third discharge gap into which the material gas is caused to flow between the normal metal electrode and the dielectric electrode or the metal electrode. In the following description, description about the same configuration as that of the embodiments described above will not be repeated.
With the configuration described above, the flow speed of the material gas flowing into the first discharge gap I1 and the second discharge gap I2 becomes higher than the flow speed of the material gas flowing into the third discharge gap into which the material gas is caused to flow between the normal metal electrode 900 and the dielectric electrode 14 or the metal electrode 13. Due to this, the flow speed of the material gas flowing into the first discharge gap I1 and the second discharge gap I2 can be increased, so that cooling efficiency of the heat sink 16 can be enhanced.
The present modification is an example in which the gas inflow port for the material gas that flows into the storage container is disposed so that the material gas swirls in a circumferential direction along the inner peripheral surface of the storage container. In the following description, description about the same points as the embodiments described above will not be repeated.
The present modification is an example of including a material gas pipe that is disposed to surround the heat sink, and has an ejection hole for ejecting the material gas toward the heat sink. In the following description, description about the same points as the first to the fourth embodiments will not be repeated.
The present modification is an example in which a pipe for cooling is disposed between the heat sink and the material gas pipe to surround the heat sink, and a cooling medium is supplied into the pipe for cooling. In the following description, description about the same points as the fourth modification will not be repeated.
The present modification is an example of including a wall for partitioning between a discharge space in which the metal electrode, the dielectric electrode, and the heat pipe are disposed, and a non-discharge space in which the heat sink is disposed. In the following description, description about the same points as the embodiments described above will not be repeated.
The gas inflow port 24 is disposed in the discharge space 1401, and the material gas is caused to flow thereinto through the gas inflow port 24. A cooling medium (for example, an insulating oil or air) for cooling the heat sink 16 is introduced into the non-discharge space 1402 through a cooling medium inflow port 1404 that is disposed on one end of an inner peripheral surface of the non-discharge space 1401, and the cooling medium is ejected through a cooling medium ejection port 1405 that is disposed on the other end of the inner peripheral surface of the non-discharge space 1402.
Due to this, it is possible to reduce a temperature rise in the heat sink 16 due to influence of a temperature rise of the material gas in at least one of the first discharge gap I1 and the second discharge gap I2, so that cooling efficiency of the heat sink 16 can be enhanced.
The present modification is an example in which an outer diameter of the heat sink is equal to or smaller than an outer diameter of the heat pipe, and the heat sink has a polygonal cross section. In the following description, description about the same points as the embodiments described above will not be repeated.
The present modification is an example in which the wall disposed in the space on the gas inlet side has a connection hole that connects the discharge space with the non-discharge space at one end thereof, and has the gas inflow port at an end opposite to the end at which the connection hole is disposed in the non-discharge space. In the following description, description about the same points as the sixth modification will not be repeated.
Due to this, the heat sink 16 can be cooled without supplying a cooling medium other than the material gas to the non-discharge space 1402, and it is possible to suppress a temperature rise of the heat sink 16 due to influence of a temperature rise of the material gas in the first discharge gap I1 or the second discharge gap I2, so that cooling efficiency of the heat sink 16 can be enhanced with a simpler configuration.
The present modification is an example in which the metal electrode includes a metal electrode not including the dielectric electrode and the heat pipe disposed on the inner peripheral surface side thereof (hereinafter, referred to as a non-discharge electrode), and the material gas is introduced into the non-discharge space through a pipe of the non-discharge electrode. In the following description, description about the same points as the eighth modification will not be repeated.
The present modification is an example in which the heat pipes are connected to one heat sink. In the following description, description about the same points as the embodiments described above will not be repeated.
Typically, the outer diameter of the heat sink 16 is often caused to be larger than the outer diameter of the heat pipe 15. Thus, if the heat sink 16 is disposed for each heat pipe 15 disposed in the storage container 12, the size of the storage container 12 is increased to prevent the adjacent heat sinks 16 from being in contact with each other. In contrast, according to the present modification, the heat pipes 15 can share the one heat sink 16, so that the size of the ozone generator can be prevented from being increased due to the heat sink 16.
The present modification is an example in which the heat sinks connected to adjacent heat pipes are alternately connected to the upstream side and the downstream side of the heat pipes in the inflow direction of the material gas. In the following description, description about the same points as the embodiment described above will not be repeated.
The present modification is an example of using the heat pipe as a grounding electrode. In the following description, description about the same points as the embodiments described above will not be repeated.
In the present modification, by applying a dielectric to the inner peripheral surface of the metal electrode 13, a dielectric electrode 14b is brought into intimate contact with the inner peripheral surface of the metal electrode 13. In the present modification, the heat pipe 15 is used as a grounding electrode that is grounded. A gap I4 (hereinafter, referred to as a discharge gap I4) into which the material gas is caused to flow is disposed between the dielectric electrode 14b and the heat pipe 15.
In the ozone generator according to the present modification, voltage is applied to the high-voltage electrode 200 to cause dielectric barrier discharge in the material gas within the third discharge gap I3 and the fourth discharge gap I4, and ozone is generated by the dielectric barrier discharge. With the ozone generator according to the present modification, the heat pipe 15 has the same potential as that of the storage container 12, so that the heat sink 16 can be disposed on the outside of the storage container 12. By water-cooling the heat sink 16 disposed on the outside of the storage container 12, efficiency in cooling the gas in the third discharge gap I3 and the fourth discharge gap I4 by the heat pipe 15 can be further enhanced, and efficiency in generating ozone in the third discharge gap I3 and the fourth discharge gap I4 can be further enhanced.
As described above, according to the first to the fifth embodiments and the first to the twelfth modifications, the material gas in the first discharge gap I1 and the second discharge gap I2 is cooled by both of the heat pipe 15 and the cooling water supplied to the outer peripheral surface of the metal electrode 13, and a temperature rise of the gas in the first discharge gap I1 and the second discharge gap I2 can be suppressed, so that efficiency in generating ozone in the first discharge gap I1 and the second discharge gap I2 can be enhanced.
In the ozone generator according to the embodiments and the modifications described above, the heat sink 16 is preferably at an upper position than the first discharge gap I1 and the second discharge gap I2 are. Due to this, the heat generated in the heat pipe 15 is enabled to easily move to the heat sink 16, and heat radiation efficiency of the heat pipe 15 can be enhanced.
In the embodiments and the modifications described above, the heat pipe 15 is used as the high-voltage electrode, and the metal electrode 13 is used as the grounding electrode. Alternatively, the metal electrode 13 may be used as the high-voltage electrode, and the heat pipe 15 may be used as the grounding electrode. For example, in a case of using the metal electrode 13 as the high-voltage electrode and using the heat pipe 15 as the grounding electrode in the configuration of the ozone generator illustrated in
In the ozone generator according to the first to the fourth embodiments and the first to the eleventh modifications, the storage container 12 is installed in a state in which the heat pipe 15 extends in parallel with a horizontal direction. Alternatively, the storage container 12 may be installed in a state in which the extending direction of the heat pipe 15 is inclined with respect to the horizontal direction, or in a state in which the extending direction of the heat pipe 15 orthogonally intersects with the horizontal direction.
Some embodiments and modifications of the present invention have been described above. However, these embodiments and modifications are merely examples, and do not intend to limit the scope of the invention. These novel embodiments and modifications can be implemented in various other forms, and can be variously omitted, replaced, and modified without departing from the gist of the present invention. These embodiments and the modifications thereof are encompassed by the scope and the gist of the present invention, and also encompassed by the invention described in CLAIMS and an equivalent thereof.
Number | Date | Country | Kind |
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2017-092379 | May 2017 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2018/010837 | 3/19/2018 | WO | 00 |