Ozone gas generator

Abstract

An ozone gas generator capable of suppressing an increase in footprint is provided. [Solution] The device comprises an oxygen gas supply unit (2) that supplies oxygen gas to a first discharge gap (11d) of a first discharge cell (120), a first power source (111) that generates a first ozone gas in the first discharge gap (11d) by applying a voltage, a first ozone gas supply unit (3) that supplies the first ozone gas to a second discharge gap (21d) of a second discharge cell (220), and a second power source (211) that generates a second ozone gas in the second discharge gap (21d) by applying a voltage, wherein the temperature of the second heat medium supplied to the second discharge cell (220) is lower than the temperature of the first heat medium supplied to the first discharge cell (120), the second discharge path length of the second discharge gap (21d) is equal to or shorter than the first discharge path length of the first discharge gap (11d), and the discharge area of ​​the second discharge cell (220) is larger than the discharge area of ​​the first discharge cell (120).

Description

[Technical Field]

[0001] The present disclosure relates to an ozone gas generator. [Background technology]

[0002] Patent Document 1 discloses an ozone gas generator. The ozone gas generator described in Patent Document 1 includes a discharge cell, a chiller that cools the cooling water by circulating the cooling water between the discharge cell, and a power supply that applies a voltage to the metal electrodes of the discharge cell. The ozone gas generator described in Patent Document 1 generates ozone gas by supplying oxygen gas from an oxygen supply facility to the discharge gap of the discharge cell and applying a voltage from the power supply. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2024-164386 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the ozone gas generator disclosed in Patent Document 1, for example, 400 g / m 3 When generating such high-concentration ozone gas, it is necessary to increase the discharge output (input power) of the ozone gas generator compared to when generating ozone gas of a lower concentration. As a result, power that does not contribute to ozone generation becomes heat and heats the discharge cells of the ozone gas generator. In a situation where the discharge cells are heated by high-power discharge, it is necessary to lower the temperature of the discharge cells to further increase the concentration of ozone gas, which requires a larger chiller. As a result, the ozone gas generator becomes larger and its footprint increases. Furthermore, the heating of the discharge cells due to discharge loss must be offset by cooling using the chiller, so the required power of the chiller also increases.

[0005] An object of the present disclosure is to provide an ozone gas generator that can suppress an increase in footprint. [Means for solving the problem]

[0006] The present invention is directed to an ozone gas generator. The ozone gas generator includes a first unit (100) having a first discharge cell (120) including a pair of first electrode layers (19, 19) and forming a first discharge gap (11d) between the pair of first electrode layers (19, 19), a first heat medium supply unit (4) that supplies a first heat medium to the first discharge cell (120) for cooling the first discharge cell (120), an oxygen gas supply unit (2) that supplies oxygen gas to the first discharge gap (11d), and a first power source (111) that applies a voltage between the pair of first electrode layers (19, 19) to generate a first ozone gas in the first discharge gap (11d), a second discharge cell (220) including a pair of second electrode layers (29, 29) and forming a second discharge gap (21d) between the pair of second electrode layers (29, 29), and a second discharge cell (220) that generates a first ozone gas in the first discharge gap (11d). and a second unit (200) having a second heat medium supply section (8) that supplies a second heat medium to the second discharge cell (220) for cooling the second discharge cell (220), and a second power source (211) that applies a voltage between the pair of second electrode layers (29, 29) while the first ozone gas is supplied to the second discharge gap (21 d) to generate a second ozone gas in the second discharge gap (21 d) that has a higher concentration than the first ozone gas, wherein the temperature of the second heat medium supplied to the second discharge cell (220) is lower than the temperature of the first heat medium supplied to the first discharge cell (120), a second discharge path length of the second discharge gap (21 d) is equal to or shorter than the first discharge path length of the first discharge gap (11 d), and a discharge area of ​​the second discharge cell (220) is larger than the discharge area of ​​the first discharge cell (120).

[0007] According to this configuration, the cooling capacity required for the second heat medium supply unit (8) can be reduced, allowing a smaller second heat medium supply unit (8) to be used, and an increase in installation space can be suppressed. As a result, an increase in the footprint of the ozone gas generator (A) can be suppressed. Furthermore, according to this configuration, the power required for the second heat medium supply unit (8) can be reduced compared to when high-concentration ozone gas is generated from oxygen gas instead of the first ozone gas by using only the second discharge cell (220) of the first discharge cell (120) and the second discharge cell (220). Furthermore, the total amount of power required for the second discharge cell (220) and the second heat medium supply unit (8) can also be reduced.

[0008] It is preferable that the second discharge path length is the same as the first discharge path length.

[0009] According to this configuration, the first discharge cell (120) and the second discharge cell (220) can share the same components, thereby reducing the manufacturing cost of the ozone gas generator (A).

[0010] It is preferable that the temperature of the second heat medium supplied to the second discharge cell (220) is 10°C or less.

[0011] According to this configuration, the second discharge cell (220) can be cooled using the second heat medium at 10° C. or less.

[0012] It is preferable that the flow rate of the second heat medium supplied to the second discharge cell (220) relative to the power supplied to the second discharge cell (220) is greater than the flow rate of the first heat medium supplied to the first discharge cell (120) relative to the power supplied to the first discharge cell (120). In this case, the first heat medium and the second heat medium may be the same type of heat medium. Alternatively, the first heat medium and the second heat medium may be different types. In this case, for example, the flow rates of the first heat medium and the second heat medium are determined taking into account the heat capacities of the first heat medium and the second heat medium.

[0013] According to this configuration, even if the amount of heat generated in the second discharge section of the second discharge cell (220) increases as the power supplied to the second discharge cell (220) increases, the flow rate of the second heat medium supplied to the second discharge cell (220) relative to the power supplied to the second discharge cell (220) can be increased so that the flow rate of the second heat medium supplied to the second discharge cell (220) relative to the power supplied to the second discharge cell (220) is greater than the flow rate of the first heat medium supplied to the first discharge cell (120) relative to the power supplied to the first discharge cell (120). This effectively ensures the flow rate of the second heat medium for cooling the second heat dissipation section. Furthermore, since the second heat medium has a lower temperature than the first heat medium, the second heat dissipation section can be sufficiently cooled by the second heat medium. As a result, the efficiency of generating the second ozone gas can be improved.

[0014] The second heat medium supply unit (8) preferably includes a cooling unit (8a) that cools the second heat medium, and a second heat medium circulation unit (8b) that circulates the second heat medium between the second discharge cell (220) and the cooling unit (8a).

[0015] According to this configuration, the second heat medium heated in the second discharge cell (220) can be cooled in the cooling section (8a) and sent to the second discharge cell (220).

[0016] The temperature of the first heat medium is preferably room temperature.

[0017] This configuration reduces the capacity of the equipment for cooling the first heat medium near the first discharge cell (120). [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic perspective view showing the appearance of an ozone gas generator. [Figure 2] FIG. 2 is a configuration diagram that schematically shows first and second discharge cells and flow paths connected to the first and second discharge cells, respectively. [Figure 3] FIG. 3 is a perspective view showing the overall configuration of the first discharge cell and the second discharge cell. [Figure 4] FIG. 4 is an exploded perspective view of the first discharge cell and the second discharge cell. [Figure 5] FIG. 5 is a schematic cross-sectional view taken along line XYZ in FIG. [Figure 6] FIG. 6 is a table showing an example of combinations of the configurations of the first discharge cells and the second discharge cells. [Figure 7] FIG. 7 is a table showing the results of a comparison of the configurations for generating high-concentration ozone gas in a conventional discharge cell and the discharge cell of this embodiment. [Figure 8A] FIG. 8A is a schematic diagram showing a conventional ozone gas generator. [Figure 8B] FIG. 8B is a schematic diagram showing the ozone gas generator of this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments shown below, and various modifications are possible within the scope of the technical concept of the present disclosure. Since the drawings are intended to conceptually explain the present disclosure, dimensions, ratios, or numbers may be exaggerated or simplified as necessary to facilitate understanding.

[0020] (1) Overall configuration of the ozone gas generator The ozone gas generator (A) is applied to, for example, semiconductor manufacturing equipment. The ozone gas generator (A) generates ozone gas. The ozone gas generator (A) generates ozone gas using high-purity oxygen gas supplied from the outside as a raw material. In the semiconductor manufacturing equipment, ozone water is generated by dissolving the ozone gas generated by the ozone gas generator (A) in water. This ozone water is used, for example, to clean silicon wafers. Alternatively, the generated ozone gas is used to form a film on a substrate.

[0021] As shown in Fig. 1, the ozone gas generator (A) includes a first unit (100) and a second unit (200). The second unit (200) can be connected to the first unit (100) afterward.

[0022] The first unit (100) includes a first casing (110), a first discharge cell (120), and a first power supply (111). The first casing (110) is formed in a hollow box shape. The first discharge cell (120) and the first power supply (111) are housed inside the first casing (110). The first power supply (111) includes a high-frequency, high-voltage power supply. The first power supply (111) supplies power to the first discharge cell (120). The first power supply (111) includes a first power supply circuit that converts the voltage of power input from a power grid to a desired voltage to generate power required by the first discharge cell (120). When oxygen gas is supplied to the first discharge cell (120), a discharge is induced when a high voltage is applied from the first power supply (111). Due to the discharge, some of the oxygen molecules dissociate into oxygen atoms, and the oxygen atoms combine with other oxygen molecules to ozonize part of the oxygen gas. As a result, a first ozone gas consisting of ozone and oxygen is generated. A first operating part (112) is provided on the front surface of the first casing (110). The first operating part (112) includes a switch, a display, a lamp, and the like.

[0023] The second unit (200) includes a second casing (210), a second discharge cell (220), and a second power source (211). The second casing (210) is formed in a hollow box shape. The second casing (210) accommodates the second discharge cell (220) and the second power source (211). The second power source (211) includes a high-frequency, high-voltage power source. The second power source (211) supplies power to the second discharge cell (220). The second power source (211) includes a second power source circuit that converts the voltage of power input from the power grid to a desired voltage to generate the power required by the second discharge cell (220). When the second discharge cell (220) is supplied with the first ozone gas, a high voltage is applied from the second power source (211), thereby inducing a discharge. The discharge dissociates some of the oxygen molecules in the first ozone gas into oxygen atoms, and these oxygen atoms combine with other oxygen molecules to generate more ozone gas. As a result, a second ozone gas with a higher concentration than the first ozone gas is generated. A second operating unit (212) is provided on the front surface of the second casing (210). The second operating unit (212) includes a switch, a display, a lamp, etc.

[0024] As shown schematically in FIG. 2, the first unit (100) includes an oxygen gas supply section (2), a first heat medium supply section (4), and a first heat medium discharge section (5).

[0025] The oxygen gas supply unit (2) supplies high-purity oxygen gas to the first discharge cell (120). The oxygen gas supply unit (2) includes an oxygen gas source (6) (oxygen cylinder) that stores oxygen gas, and a tubular oxygen gas supply path (2a) that connects the oxygen gas source (6) and the first discharge cell (120).

[0026] The first heat medium supply unit (4) supplies a first heat medium to the first discharge cells (120) for cooling the first discharge cells (120). The first heat medium is, for example, water at room temperature. The first heat medium supply unit (4) includes a first heat medium supply path (4a) for supplying the first heat medium to the first discharge cells (120).

[0027] The first heat medium discharge unit (5) discharges the first cooling water used to cool the first discharge cells (120). The first heat medium discharge unit (5) includes a first heat medium discharge path (5a) for sending the first cooling water flowing out of the first discharge cells (120) to a predetermined first discharge flow path.

[0028] The second unit (200) includes a first ozone gas supply channel (3a), a second ozone gas discharge part (7), and a second heat medium supply part (8).

[0029] The first ozone gas supply path (3a) is a tubular member. The first ozone gas supply path (3a) is connected to the first discharge cell (120) and the second discharge cell (220). The first ozone gas supply path (3a) sends the first ozone gas generated in the first discharge cell (120) to the second discharge cell (220).

[0030] The second ozone gas discharge unit (7) supplies the second ozone gas generated in the second discharge cell (220) to a predetermined target. The second ozone gas discharge unit (7) includes an exhaust path (7a). The exhaust path (7a) is a tubular member. The exhaust path (7a) supplies the second ozone gas from the second discharge cell (220) to a predetermined target.

[0031] The second heat medium supply unit (8) supplies a second heat medium (e.g., second cooling water) to the second discharge cells (220) for cooling the second discharge cells (220). The second heat medium supply unit (8) includes a cooling unit (8a) that cools the second heat medium, and a second heat medium circulating unit (8b) that circulates the second heat medium between the second discharge cells (220) and the cooling unit (8a). The second heat medium supply unit (8) cools the second heat medium using the cooling unit (8a) while circulating the second heat medium between the second discharge cells (220) and the cooling unit (8a) using the second heat medium circulating unit (8b).

[0032] The cooling unit (8a) includes a refrigeration circuit that cools the second heat medium and a chiller power supply. The refrigeration circuit includes a compressor, a condenser, an expansion valve, and an evaporator, and is configured so that the compressor, condenser, expansion valve, and evaporator are connected in a ring shape in this order. The compressor compresses and discharges refrigerant. The condenser condenses the refrigerant discharged from the compressor by exchanging heat with air or water. The expansion valve expands the refrigerant condensed by the condenser. The evaporator evaporates the refrigerant by exchanging heat with the second heat medium after the refrigeration circuit expands the refrigerant. The chiller power supply includes a power supply circuit that supplies power to components (e.g., the compressor) of the cooling unit (8a). In this embodiment, the refrigeration cycle performed in the refrigeration circuit is a vapor compression refrigeration cycle, but the type of refrigeration cycle is not particularly limited. The refrigeration cycle may be, for example, an air refrigeration cycle that generates low temperatures by compressing, cooling, and expanding a gas.

[0033] The second heat medium circulating unit (8b) includes a second heat medium supply path (8b1), a second heat medium discharge path (8b2), a tank (8b3), and a pump (8b4). The second heat medium supply path (8b1) is a tubular member connected to the cooling unit (8a), the second discharge cell (220), the tank (8b3), and the pump (8b4) and configured to send the second heat medium from the cooling unit (8a) to the second discharge cell (220). The second heat medium discharge path (8b2) is a tubular member connected to the cooling unit (8a) and the second discharge cell (220) and configured to send the second heat medium that has passed through the second discharge cell (220) to the cooling unit (8a). The tank (8b3) is connected to the inlet side of the pump (8b4) and stores the second heat medium. The second heat medium is pumped by a pump (8b4) and circulates through a second heat medium supply path (8b1) and a second heat medium discharge path (8b2) between the cooling section (8a) and the second discharge cell (220). After passing through the second discharge cell (220), the second heat medium is sent to the cooling section (8a) through the second heat medium discharge path (8b2), where it is cooled by heat exchange with a refrigerant while passing through an evaporator. Thereafter, the second heat medium is sent to the second discharge cell (220) through the second heat medium supply path (8b1).

[0034] (2) First discharge cell 3, the first discharge cell (120) has a first cell body (121) having a rectangular pillar-like appearance, and electric wires (1a, 1b) extending from the first power source (111) are connected to terminals (1c) provided at the four corners of the first cell body (121). More specifically, a pair of high-voltage electric wires (1a) extending from the first power source (111) is connected to one of two adjacent terminals (1c). A pair of low-voltage electric wires (1b) extending from the first power source (111) is connected to the other two terminals (1c).

[0035] A first gas inlet (121a), a first gas outlet (121b), a first heat medium inlet (121c), and a first heat medium outlet (121d) are provided on four sides of the top surface of the first cell body (121). More specifically, the first gas inlet (121a) and the first gas outlet (121b), and the first heat medium inlet (121c) and the first heat medium outlet (121d) are arranged opposite each other in the middle of the edge portion of each side.

[0036] The first gas inlet (121a) is connected to the oxygen gas supply channel (2a). The first gas outlet (121b) is connected to the first ozone gas supply channel (3a). The first heat medium inlet (121c) is connected to the first heat medium supply channel (4a). The first heat medium outlet (121d) is connected to the first heat medium discharge channel (5a).

[0037] 4, the first cell body (121) is formed by stacking, in the thickness direction, substantially square substrates of the same size but with different functions, such as first dielectric plates (11a, 11b), first insulating plates (12a, 12b), first flow path substrates (13a, 13b), and first cover plates (14a, 14b). Specifically, a pair of first dielectric plates (11a, 11b) are arranged abutting each other between the upper and lower first cover plates (14a, 14b), and a pair of first insulating plates (12a, 12b) and a pair of first flow path substrates (13a, 13b) are arranged symmetrically above and below the first dielectric plates (11a, 11b).

[0038] These substrates are bonded together using a glass-based paste. Element holes (15) with circular cross sections are formed at the four corners of each substrate, penetrating the substrate in the thickness direction. Terminal portions (1c) are formed in these element holes (15).

[0039] The first dielectric plates (11a, 11b), the first insulating plates (12a, 12b), and the first flow path substrates (13a, 13b) are combined to form a cell element (16) that is the basis of the first discharge cell (120). The first discharge cell (120) includes a single cell element (16) or a plurality of stacked cell elements (16). The number of stacked cell elements (16) in the first cell body (121) is set according to the first ozone gas generation capacity, while sharing the first flow path substrates (13a, 13b) between the upper and lower first cover plates (14a, 14b). The number of stacked cell elements (16) shown in FIG. 4 is an example and is not limited to that shown in FIG. 4.

[0040] Gas elongated holes (17a, 17b) penetrate the first dielectric plates (11a, 11b), the first insulating plates (12a, 12b), and the first flow path substrates (13a, 13b). As shown by the solid arrows in Fig. 4, the gas elongated holes (17a) on one side overlap to form a vertical gas flow path (17A) that communicates with the first gas inlet (121a), and the gas elongated holes (17b) on the other side overlap to form a vertical gas flow path (17B) that communicates with the first gas outlet (121b).

[0041] Slots (18a, 18b) penetrate the first dielectric plates (11a, 11b) and the first insulating plates (12a, 12b). As shown by the dashed arrows in Fig. 4, the slots (18a) on one side overlap to form a vertical flow path (18A) that communicates with the first heat medium inlet (121c), and the slots (18b) on the other side overlap to form a vertical flow path (18B) that communicates with the first heat medium outlet (121d).

[0042] A plurality of first ribs (11c) are formed on the opposing surfaces of the first dielectric plates (11a, 11b) and are aligned perpendicular to the gas slots (17a, 17b). A first electrode layer (19) with excellent electrical conductivity is formed on the back surface of each first dielectric plate (11a, 11b). Specifically, the first electrode layer (19) has an electrode portion (19a) extending over an area surrounded by the pair of gas slots (17a, 17b) and the pair of slots (18a, 18b), and a pair of terminal electrode portions (19b) extending from the electrode portion (19a) to each of two adjacent corners of the first dielectric plates (11a, 11b).

[0043] The first flow path substrates (13a, 13b) are provided with a plurality of cooling elongated holes (13c) arranged parallel to the pair of gas elongated holes (17a, 17b) between the pair of gas elongated holes (17a, 17b). Both ends of the cooling elongated holes (13c) extend to the vicinity of the edges of the first insulating plates (12a, 12b) so as to overlap with and communicate with the vertical flow paths (18A, 18B). The plurality of cooling elongated holes (13c) and the vertical flow paths (18A, 18B) form a first heat medium flow path.

[0044] FIG. 5 shows a cross-sectional structure of the first cell body (121) taken along line XYZ in FIG.

[0045] Between the pair of first electrode layers (19, 19) (between the pair of first dielectric plates (11a, 11b)), a first discharge gap (11d) is formed, which is divided into a plurality of flow paths by the joined first ribs (11c). A vertical gas flow path (17A) formed in the first discharge cell (120) connects the first discharge gap (11d) and the oxygen gas supply unit (2). Oxygen gas supplied from the oxygen gas supply unit (2) to the first discharge cell (120) is sent to the first discharge gap (11d) through the vertical gas flow path (17A). As indicated by the solid arrow in the figure, oxygen gas flowing in from the first gas inlet (121a) flows through the vertical gas flow path (17A) into the first discharge gap (11d). As indicated by the dotted arrows, the first heat medium flowing in through the first heat medium inlet (121c) passes through the vertical flow passage (18A) into each cooling slot (13c), and then passes through the other vertical flow passage (18B) to exit through the first heat medium outlet (121d). The first heat medium cools the first discharge section while flowing through the cooling slot (13c). The pair of first electrode layers (19, 19) (see FIGS. 4 and 5) and the first discharge gap (11d) formed between the pair of first electrode layers (19, 19) constitute the first discharge section.

[0046] When a high voltage is applied between the pair of first electrode layers (19, 19), a silent discharge occurs in the first discharge gap (11d). Due to the action of this silent discharge, some oxygen molecules dissociate into oxygen atoms in the first discharge gap (11d). These oxygen atoms combine with other oxygen molecules, converting some of the oxygen gas into ozonation, thereby generating a first ozone gas consisting of ozone and oxygen. The generated first ozone gas flows out of the first discharge gap (11d), passes through the vertical gas flow path (17B), and flows out of the first gas outlet (121b). The vertical gas flow path (17B) formed in the first discharge cell (120) connects the first discharge gap (11d) and the first ozone gas supply path (3a). The first ozone gas generated in the first discharge gap (11d) is sent to the first ozone gas supply path (3a) through the vertical gas flow path (17B).

[0047] (3) Second discharge cell 3, the second discharge cell (220) has substantially the same structure as the first discharge cell (120). The second discharge cell (220) has a second cell body (221), and a high-voltage side electric wire (1d) and a low-voltage side electric wire (1e) extending from a second power source (211) are connected to terminal portions (1f) provided at the four corners of the second cell body (221).

[0048] A second gas inlet (221a), a second gas outlet (221b), a second heat medium inlet (221c), and a second heat medium outlet (221d) are provided on four sides of the top surface of the second cell body (221).

[0049] As shown in FIG. 4, the second cell body (221) is formed by stacking, in the thickness direction, substantially square-shaped substrates of the same dimensions with different functions, such as second dielectric plates (21a, 21b), second insulating plates (22a, 22b), second flow path substrates (23a, 23b), and second cover plates (24a, 24b).

[0050] The second dielectric plates (21a, 21b), the second insulating plates (22a, 22b), and the second flow path substrates (23a, 23b) are combined to form a cell element (26) that forms the basis of the second discharge cell (220). The second discharge cell (220) includes a single cell element (26) or a plurality of stacked cell elements (26). The number of stacked cell elements (26) in the second cell body (221) is set according to the second ozone gas generation capacity, while sharing the second flow path substrates (23a, 23b) between the upper and lower second cover plates (24a, 24b). The number of stacked cell elements (26) shown in FIG. 4 is an example and is not limited to that shown in FIG. 4.

[0051] Gas elongated holes (27a, 27b) extending along each of the second dielectric plates (21a, 21b), the second insulating plates (22a, 22b), and the second flow path substrates (23a, 23b) penetrate through opposing sides of the second dielectric plates (21a, 21b), the second insulating plates (22a, 22b), and the second flow path substrates (23a, 23b), respectively. As shown by the solid arrows in Fig. 4, the gas elongated holes (27a) on one side overlap to form a vertical gas flow path (27A) communicating with the second gas inlet (221a), and the gas elongated holes (27b) on the other side overlap to form a vertical gas flow path (27B) communicating with the second gas outlet (221b).

[0052] Slots (28a, 28b) extending along the other opposing sides of the second dielectric plates (21a, 21b) and the second insulating plates (22a, 22b) also penetrate the other opposing sides, respectively. As indicated by the dashed arrow in Fig. 4, the slots (28a) on one side overlap to form a vertical flow path (28A) communicating with the second heat medium inlet (221c), and the slots (28b) on the other side overlap to form a vertical flow path (28B) communicating with the second heat medium outlet (221d).

[0053] A plurality of second ribs (21c) are formed on the opposing surfaces of the second dielectric plates (21a, 21b) and are aligned perpendicular to the gas slots (27a, 27b). A second electrode layer (29) having excellent electrical conductivity is formed in a predetermined shape on the back surface of each second dielectric plate (21a, 21b). Specifically, the second electrode layer (29) has an electrode portion (29a) and a terminal electrode portion (29b). The pair of second dielectric plates (21a, 21b) and the second electrode layers (29) formed on the back surfaces of the pair of second dielectric plates (21a, 21b) constitute a second discharge portion.

[0054] The second flow path substrates (23a, 23b) are provided with a plurality of cooling elongated holes (23c) arranged parallel to the pair of gas elongated holes (27a, 27b) between the pair of gas elongated holes (27a, 27b). Both ends of the cooling elongated holes (23c) extend to the vicinity of the edges of the second insulating plates (22a, 22b) so as to overlap with and communicate with the vertical flow paths (28A, 28B). A second bonding layer (22c) is interposed between the substrates of the second cell body (221).

[0055] As shown in Fig. 5, a second discharge gap (21d) partitioned into a plurality of flow paths by joined second ribs (21c) is formed between a pair of second electrode layers (29, 29) (between a pair of second dielectric plates (21a, 21b)). A vertical gas flow path (27A) formed in the second discharge cell (220) connects the second discharge gap (21d) to the first ozone gas supply path (3a). The first ozone gas sent to the second discharge cell (220) through the first ozone gas supply path (3a) is sent to the second discharge gap (21d) through the vertical gas flow path (27A). The first ozone gas flowing in from the second gas inlet (221a) flows into the second discharge gap (21d) through the vertical gas flow path (27A). The second heat medium flowing in through the second heat medium inlet (221c) flows through the vertical flow passage (28A) into each cooling slot (23c), and then flows through the other vertical flow passage (28B) and out of the second heat medium outlet (221d). The second heat medium cools the second discharge section while flowing through the cooling slot (23c). The pair of second electrode layers (29, 29) (see FIGS. 4 and 5) and the second discharge gap (21d) formed between the pair of second electrode layers (29, 29) constitute the second discharge section.

[0056] When a high voltage is applied between the pair of second electrode layers (29, 29), a silent discharge occurs in the second discharge gap (21d). Due to the action of this silent discharge, some of the oxygen molecules in the first ozone gas dissociate into oxygen atoms in the second discharge gap (21d). These oxygen atoms combine with other oxygen molecules, converting some of the oxygen gas into ozonized oxygen. As a result, a second ozone gas with a higher concentration than the first ozone gas is generated. The generated second ozone gas flows out of the second discharge gap (21d), passes through the vertical gas flow path (27B), and flows out of the second gas outlet (221b). The vertical gas flow path (27B) formed in the second discharge cell (220) connects the second discharge gap (21d) and the discharge path (7a). The second ozone gas generated in the second discharge gap (21d) is sent to the discharge path (7a) through the vertical gas flow path (27B). The ozone gas generator (A) has a control unit including a processor such as a CPU and an MPU, and the control unit controls various components of the ozone gas generator (A) (compressor, pump (8b4), first power supply (111), chiller power supply, second power supply (211), etc.).

[0057] (4) Characteristics of the ozone gas generator The ozone gas generator (A) generates a first ozone gas with a low concentration in the first discharge cell (120), and generates a second ozone gas with a high concentration in the second discharge cell (220) using the first ozone gas with a low concentration generated in the first discharge cell (120). For example, the low concentration is 400 g / m 3 The highest concentration is less than 400 g / m 3 When generating a low-concentration first ozone gas, a first heat medium having a first predetermined temperature that is normally used is used. The first predetermined temperature is, for example, 20°C, 25°C, or the like, and is a temperature greater than 10°C. When generating a high-concentration second ozone gas, a second heat medium having a specially used second predetermined temperature is used. The second predetermined temperature is, for example, -20°C, or the like, and is a temperature less than 10°C. Generally, 400 g / m 3 When generating a high concentration of secondary ozone gas, a secondary heat medium of about 5°C to 10°C is used, and the temperature is 500g / m 3 When generating the second ozone gas having such a high concentration, a second heat medium at about -20°C is used.

[0058] The table shown in Fig. 6 was obtained by conducting tests by the inventors of the present application. Fig. 6 shows an example of a combination of the configurations of the first discharge cell (120) and the second discharge cell (220) such that a low-concentration first ozone gas is generated in the first discharge cell (120) by supplying oxygen gas and a first heat medium (first cooling water) to the first discharge cell (120), and a high-concentration second ozone gas is generated in the second discharge cell (220) by supplying the first ozone gas and a second heat medium (second cooling water) whose temperature is lower than that of the first heat medium to the second discharge cell (220). For example, the temperature of the first heat medium is about 20°C to 25°C, and the temperature of the second heat medium is about 5°C to 10°C. In Fig. 6, the first half shows the first discharge cell (120), and the second half shows first to third examples (Z1) to (Z3) of the second discharge cell (220). The first discharge cell (120) is connected in series to each of the first to third examples (Z1) to (Z3) of the second discharge cell (220). In each of the first to third examples (Z1) to (Z3) of the first discharge cell (120) shown in FIG. 6, the concentration (low concentration) of the generated first ozone gas is 335 g / m 3 The power (input power) supplied from the first power source (111) is 1.8 kW to 2.1 kW. In each of the first example (Z1) to the third example (Z3) of the second discharge cell (220) shown in FIG. 6, the concentration (high concentration) of the generated second ozone gas is 440 g / m 3 and the power (input power) supplied from the second power source (211) is 2.4 kW to 2.6 kW.

[0059] In each of the first to third examples (Z1) to (Z3) of the second discharge cell (220), the second discharge path length of the second discharge gap (21d) is equal to or shorter than the first discharge path length of the first discharge gap (11d) in the first discharge cell (120). For example, each of the first discharge path length and the second discharge path length is 140 mm. The first discharge path length is the length in the direction of oxygen gas flow at the portion where the first discharge gap (11d) and the electrode portion (19a) overlap in a plan view (see FIGS. 4 and 5). That is, the first discharge path length is the dimension in the direction in which oxygen gas or first ozone gas flows in the first discharge gap (11d). The second discharge path length is: That is, the second discharge path length is the dimension in the direction in which the first ozone gas or second ozone gas flows in the second discharge gap (21d).

[0060] As shown in Fig. 6, when the first discharge cell (120) is compared with the first example (Z1) to the third example (Z3) of the second discharge cell (220), the second discharge path length of the second discharge gap (21d) is equal to or shorter than the first discharge path length of the first discharge gap (11d), and the discharge area of ​​the second discharge cell (220) is larger than the discharge area of ​​the first discharge cell (120). As shown in Figs. 4 and 5, the discharge area of ​​the first discharge cell (120) is the area of ​​the overlapping portion between the electrode portion (19a) of the first discharge cell (120) and the first discharge gap (11d) minus the area of ​​the overlapping portion between the electrode portion (19a), the first discharge gap (11d), and the first rib (11c). The first discharge cell (120) includes a single first discharge gap (11d) or a plurality of first discharge gaps (11d) stacked in multiple stages. The discharge area of ​​the second discharge cell (220) is the area of ​​the overlapping portion between the electrode portion (29a) and the second discharge gap (21d) of the second discharge cell (220) minus the area of ​​the overlapping portion between the electrode portion (29a), the second discharge gap (21d), and the second rib (21c). The second discharge cell (220) includes a single second discharge gap (21d) or a plurality of second discharge gaps (21d) stacked in a plurality of stages. Note that when calculating the discharge area of ​​the discharge cells (120, 220), the area of ​​the surface of the electrode portion (19a, 29a) located either above or below the discharge gap (11d, 21d) is used for calculation, rather than the sum of the areas of the surfaces located above and below the discharge gap (11d, 21d).

[0061] Therefore, in the ozone gas generator (A), the second discharge path length of the second discharge gap (21d) is equal to or shorter than the first discharge path length of the first discharge gap (11d), and the discharge area of ​​the second discharge cell (220) is larger than the discharge area of ​​the first discharge cell (120). If the second discharge path length of the second discharge gap (21d) is longer than the first discharge path length of the first discharge gap (11d), the discharge in the second discharge cell (220) may cause ozone to be decomposed and converted back into oxygen molecules, which may result in a problem of a decrease in the ozone concentration of the second ozone gas. Furthermore, if the discharge area of ​​the first discharge cell (120) is larger than the discharge area of ​​the second discharge cell (220), the power density of the second discharge cell (220) increases, and the increased discharge density places a strain on the dielectric on the surface of the second discharge gap (21d), which may cause the dielectric on the surface of the second discharge gap (21d) to peel off and become mixed into the second ozone gas as contamination. Furthermore, the increased power density of the second discharge cell (220) may increase the temperature of the second discharge cell (220), which may accelerate ozone decomposition and reduce the concentration of the second ozone. In contrast, in this embodiment, the second discharge path length of the second discharge gap (21d) is equal to or shorter than the first discharge path length of the first discharge gap (11d), and the discharge area of ​​the second discharge cell (220) is larger than the discharge area of ​​the first discharge cell (120). This prevents the above problem from occurring. Furthermore, by making the discharge area of ​​the second discharge cell (220) larger than the discharge area of ​​the first discharge cell (120), the amount of ozone gas generated in the second discharge cell (220) can be increased, and therefore, the second ozone gas having a higher concentration than the first ozone gas can be more effectively generated in the second discharge cell (220). Furthermore, the second discharge path length of the second discharge cell (220) may be configured to be the same as the first discharge path length of the first discharge cell (120). This allows the first discharge cell (120) and the second discharge cell (220) to use the same components, thereby reducing the manufacturing cost of the ozone gas generator (A).

[0062] (5) Comparison with conventional technology As shown in FIG. 8A, a conventional ozone gas generator (1000) uses a single discharge cell (1100), supplies oxygen gas to the discharge cell (1100), and generates high-concentration ozone gas from the oxygen gas in the discharge cell (1100) all at once. In the conventional ozone gas generator (1000), a heat medium circulates between the discharge cell (1100) and a cooling unit (1200). The cooling unit (1200) includes a refrigeration circuit (compressor, condenser, expansion valve, evaporator, etc.), a chiller power supply, etc., and cools the heat medium. In contrast, as shown in FIG. 8B, an ozone gas generator (A) of this embodiment generates a low-concentration first ozone gas from oxygen gas in a first discharge cell (120) in the front stage, and generates a high-concentration second ozone gas from the first ozone gas in a second discharge cell (220) in the rear stage. The ozone gas generator (A) of this embodiment shown in Figure 8B has the above-mentioned features (the second discharge path length of the second discharge gap (21d) is equal to or shorter than the first discharge path length of the first discharge gap (11d), and the discharge area of ​​the second discharge cell (220) is larger than the discharge area of ​​the first discharge cell (120). The ozone gas generator (A) of this embodiment includes, with respect to the discharge cells, an ozone gas generator (A) (Embodiment 1) configured with a first discharge cell (120) and a second discharge cell (Z1) shown in Figure 6, an ozone gas generator (A) (Embodiment 2) configured with a first discharge cell (120) and a second discharge cell (Z2), and an ozone gas generator (A) (Embodiment 3) configured with a first discharge cell (120) and a second discharge cell (Z3) (see Figure 7).

[0063] 7 shows the results of a comparison of the configurations for generating high-concentration ozone gas (second ozone gas) between the conventional ozone gas generator (1000) shown in FIG. 8A and the ozone gas generator (A) of this embodiment shown in FIG. 8B. In this configuration, a low-temperature heat medium (second heat medium) of 5 to 10°C is used, and the ozone gas is 440 g / m 3 High-concentration ozone gas (second ozone gas) is generated. In Fig. 7, the chiller indicates the cooling section (1200) in the conventional ozone gas generator (1000), and indicates the cooling section (8a) in the ozone gas generator (A) of this embodiment. The chiller generates a low-temperature (5°C to 10°C) heat medium (second heat medium).

[0064] As shown in FIG. 7, in order to generate high-concentration ozone gas, 40 cell elements (16) were required for the discharge cell (1100) of the conventional ozone gas generator (1000). In the ozone gas generators (A) of the first to third embodiments, 10 cell elements (16) are required for the first discharge cell (120). In the ozone gas generator (A) of the first embodiment, 12 cell elements (16) are required for the second discharge cell (220). In the ozone gas generator (A) of the second embodiment, 16 cell elements (16) are required for the second discharge cell (220). In the ozone gas generator (A) of the third embodiment, 20 cell elements (16) are required for the second discharge cell (220). The total number of cell elements is smaller in the ozone gas generator (A) of the present embodiment than in the conventional ozone gas generator (1000). As a result, the ozone gas generator (A) of this embodiment can reduce the number of parts and size of the discharge cells (120, 220) while maintaining the same gas flow rate and ozone concentration as the conventional ozone gas generator (1000).

[0065] Furthermore, the chiller of this embodiment (the cooling section (8a)) requires a lower cooling capacity than the conventional chiller (the cooling section (1200)) (see "Cooling Capacity" in FIG. 7). As a result, the chiller of this embodiment requires a lower cooling capacity than the conventional chiller, allowing a smaller chiller to be used. This prevents an increase in the installation space for the cooling section (8a) serving as a chiller. As a result, the present embodiment prevents an increase in the footprint of the ozone gas generator (A). Furthermore, compared to the conventional chiller, the present embodiment can reduce the power input (required power) to the second heat medium supply section (8) (the cooling section (8a) serving as a chiller). Furthermore, the total amount of power required by the second discharge cell (220) and the second heat medium supply section (8) can also be reduced. As a result, the ozone gas generator (A) of this embodiment can reduce the number of parts in the discharge cells (120, 220), the size of the chiller required, and power at the same gas flow rate and ozone concentration, compared to the conventional ozone gas generator (1000). Furthermore, the ozone gas generator (A) of this embodiment can reduce the power input to the discharge cells (120, 220) at the same gas flow rate and ozone concentration, compared to the conventional ozone gas generator (1000).

[0066] (6) Other embodiments The first heat medium and the second heat medium do not have to be water, but may be liquids such as refrigerants or brine. The water may be pure water or city water. The heat medium may be any fluid, and may be gas instead of liquid.

[0067] The first heat medium and the second heat medium cooled both the high-voltage side and the low-voltage side electrode portions (19a, 29a), but a structure in which either one is supplied to only one side and cools the discharge gap (11d, 21d) from either one side may also be used.

[0068] The first discharge cell (120) and the second discharge cell (220) may be a single-sided barrier type in which a discharge gap is provided between a metal electrode and a dielectric in the ozone generating section, and discharge is utilized from one direction, or may be a double-sided barrier type in which a dielectric is sandwiched between two metal electrodes in the ozone generating section, and discharge is utilized from both sides.

[0069] The discharge cells (120, 220) are not limited to being flat plates, but may be pipe-shaped.

[0070] A plurality of first discharge cells (120) may be arranged in parallel. The first power source (111) and the second power source (211) may be common. The first discharge cell (120) and the second discharge cell (220) may not be connected by the first ozone gas supply path (3a), but may share some components, thereby being physically integrated. The second ozone gas discharged from the second discharge cell (220) may be supplied to the third or subsequent discharge cells to generate ozone gas. The components of the first unit (100) and the second unit (200) may be housed in different housings and separated from each other. The components of the first unit (100) and the second unit (200) may be housed in the same housing and integrated.

[0071] Although the embodiments and modifications have been described above, it will be understood that various changes in form and details are possible without departing from the spirit and scope of the claims. Furthermore, elements of the above embodiments, modifications, and other embodiments may be combined or substituted as appropriate.

[0072] The terms "first," "second," "third," etc. mentioned above are used to distinguish the terms to which these terms are attached, and do not limit the number or order of the terms. [Industrial Applicability]

[0073] As described above, the present disclosure is useful for ozone gas generators. [Explanation of symbols]

[0074] A. Ozone gas generator 19 1st electrode layer 11d 1st discharge gap 13c Cooling slot 17A, 17B, 27A, 27B Gas vertical flow path 18A,18B,28A,28B Vertical channel 120 First discharge cell 29 Second electrode layer 21d 2nd discharge gap 23c Cooling slot 28A vertical flow path 28B Vertical channel 220 Second discharge cell

Claims

1. a first unit (100) including a first discharge cell (120) including a pair of first electrode layers (19, 19) and forming a first discharge gap (11d) between the pair of first electrode layers (19, 19), a first heat medium supply unit (4) that supplies a first heat medium to the first discharge cell (120) for cooling the first discharge cell (120), an oxygen gas supply unit (2) that supplies oxygen gas to the first discharge gap (11d), and a first power source (111) that applies a voltage between the pair of first electrode layers (19, 19) to generate a first ozone gas in the first discharge gap (11d); a second unit (200) including a second discharge cell (220) including a pair of second electrode layers (29, 29) and forming a second discharge gap (21d) between the pair of second electrode layers (29, 29); a second heat medium supply unit (8) that supplies a second heat medium to the second discharge cell (220) for cooling the second discharge cell (220); and a second power source (211) that applies a voltage between the pair of second electrode layers (29, 29) while the first ozone gas is supplied to the second discharge gap (21d) to generate a second ozone gas having a higher concentration than the first ozone gas in the second discharge gap (21d), the temperature of the second heat medium supplied to the second discharge cell (220) is lower than the temperature of the first heat medium supplied to the first discharge cell (120); a second discharge path length of the second discharge gap (21d) is equal to or shorter than a first discharge path length of the first discharge gap (11d); The ozone gas generator, wherein the discharge area of ​​the second discharge cell (220) is larger than the discharge area of ​​the first discharge cell (120).

2. 2. The ozone gas generator according to claim 1, wherein the second discharge path length is the same as the first discharge path length.

3. 2. The ozone gas generator according to claim 1, wherein the temperature of the second heat medium supplied to the second discharge cell (220) is 10° C. or less.

4. 3. The ozone gas generator according to claim 1, wherein a flow rate of the second heat medium supplied to the second discharge cell (220) relative to the power supplied to the second discharge cell (220) is greater than a flow rate of the first heat medium supplied to the first discharge cell (120) relative to the power supplied to the first discharge cell (120).

5. 3. The ozone gas generator according to claim 1, wherein the second heat medium supply unit (8) includes a cooling unit (8a) that cools the second heat medium, and a second heat medium circulation unit (8b) that circulates the second heat medium between the second discharge cell (220) and the cooling unit (8a).

6. 3. The ozone gas generator according to claim 1, wherein the temperature of the first heat medium is room temperature.

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