Ozone water generation device and ozone water generation method

Abstract

In an ozone water generation device 1, a tank 2 stores water. A pump 3 is disposed below the tank 2. An ejector 4 is disposed between the tank 2 and the pump 3 vertically, injects ozone gas suctioned from the outside into the water introduced from the tank 2, and ejects ozone water. A return line 5 returns the ejected ozone water to the tank 2.

Description

Ozone water generator and ozone water generation method

[0001] The present invention relates to an ozone water generation method using ozone gas and an apparatus therefor.

[0002] As an ozone water generator for dissolving ozone gas in water to generate ozone water, for example, there is an ejector type as disclosed in Patent Documents 1 and 2.

[0003] In an ejector type ozone water generator, when a negative pressure occurs in an ozone generator connected to the suction port of the ejector, the probability of a decrease in ozone gas generation ability and a malfunction of the ozone generator increases. Therefore, the ozone water generator of Patent Document 1 provides an orifice between the ozone generator and the ejector to maintain the ozone gas generation unit of the ozone generator at a positive pressure, and supplies ozone gas to the ejector under the same pressure. [[ID=IO]] [[ID=II]]

[0004] The ozone water supply system of Patent Document 2 includes a supply line for ozone water, a circulation line for ozone water, an ozone concentration sensor, and a controller for the generated ozone concentration of an ozone generator, and controls to eliminate fluctuations in ozone concentration during the discharge of ozone water to the supply line or the like. The ozone gas used as a raw material for ozone water is generated by a discharge type ozonizer that generates ozone gas by discharging, with oxygen as the main raw material, and the supply pressure is normal pressure or higher.

[0005] Japanese Patent No. 4746515, Japanese Patent No. 7041466, Japanese Patent No. 4186551, Japanese Patent No. 411818S

[0006] The above prior art generates ozone water by mixing ozone gas and water using a gas-liquid mixing device such as an ejector. The supply pressure of the ozone gas at this time is considered to be a positive pressure.

[0007] On the other hand, some ozone gas generators (ozonizers) hold ozone gas at a negative pressure inside the device for the purpose of suppressing self-decomposition of highly concentrated ozone gas. It is possible to generate ozone water using a conventional ejector for such an ozonizer.

[0008] However, if air enters the system, the pump in the ozonated water circulation line may run dry, reducing the circulation flow rate, which can lead to a decrease in the ejector's suction pressure, unstable operation, and ultimately a decrease in the ozonated water concentration.

[0009] Furthermore, in the conventional ozonated water generation technology described above, a method can be considered to increase the flow rate by connecting ejectors in parallel, which can be applied to an ozonizer that holds ozone gas under negative pressure, and to achieve a large-capacity supply of ozonated water of several liters / min or more, as is commonly used.

[0010] However, if sufficient suction pressure cannot be obtained due to variations in the supply water pressure or malfunctions in the circulation pump in parallel ejectors, water may flow back into the ozone gas supply system and enter the ozone gas flow meter or valves, potentially causing malfunctions or failures in the ozone gas supply system.

[0011] In view of the above circumstances, the present invention aims to stabilize the operation of an ozone water generator at startup by reducing the amount of bubbles that remain in the pump of the ozone water generator, thereby suppressing the pump from running dry.

[0012] Furthermore, the present invention aims to suppress variations in ozone gas supply when ozone gas is supplied to parallel ejectors along with water to produce ozonated water, and to prevent liquid backflow from the ozone gas intake of the ejectors from entering the ozone gas supply system.

[0013] Therefore, one aspect of the present invention is an ozone water generating apparatus comprising a tank for storing water, a pump disposed below the tank, an ejector disposed vertically between the tank and the pump for injecting ozone gas drawn from the outside into the water introduced from the tank to discharge ozone water, and a return line capable of returning the discharged ozone water to the tank.

[0014] In one aspect of the present invention, in the ozone water generator, the ejectors are arranged in parallel in a plurality of configurations.

[0015] In one aspect of the present invention, in the ozone water generating apparatus, the ejectors are arranged at equal intervals on concentric circles centered on the suction center of the pump.

[0016] One aspect of the present invention is an ozone water generating apparatus in which the tank is provided with an exhaust line for discharging the gas inside the tank.

[0017] One aspect of the present invention is an ozone water generating apparatus in which the exhaust line includes an ozone decomposer that decomposes the ozone contained in the gas discharged from the tank.

[0018] One aspect of the present invention is an ozone water generation method, comprising an ozone water generation apparatus comprising a tank for storing water, a pump disposed below the tank, and an ejector disposed vertically between the tank and the pump, the method comprising the steps of injecting ozone gas drawn from an external source into the water introduced from the tank into the ejector and discharging ozone water from the ejector, and returning the discharged ozone water to the tank.

[0019] Furthermore, one aspect of the present invention is an ozone water generating apparatus comprising: a tank for storing water; a pump disposed below the tank; a plurality of parallel ejectors disposed vertically between the tank and the pump for injecting ozone gas into the water introduced from the tank and discharging ozonated water; a buffer tank capable of storing the ozone gas introduced by suction from the outside or the liquid that flows back from the ozone gas intake of the plurality of parallel ejectors; and a return line capable of returning the discharged ozonated water to the tank.

[0020] One aspect of the present invention is an ozone water generator in which the buffer tank is positioned between the plurality of parallel ejectors and the pump, and the ozone gas suction line connecting the buffer tank and the suction ports of the plurality of parallel ejectors has a piping distance equivalent to that between the buffer tank and the suction ports of the plurality of parallel ejectors.

[0021] One aspect of the present invention is an ozone water generator in which the buffer tank is a donut-shaped tank that surrounds the ozone water suction line coaxially with the ozone water suction line that connects the plurality of parallel ejectors and the pump.

[0022] One aspect of the present invention is an ozone water generator in which the buffer tank contains the plurality of parallel ejectors.

[0023] One aspect of the present invention is an ozone water generator in which the liquid level of the buffer tank is controlled based on the liquid level detected by a liquid level sensor provided in the buffer tank.

[0024] According to the present invention described above, the amount of bubbles remaining in the pump of the ozone water generator is reduced, and the pump's idle operation is suppressed, resulting in stable operation of the ozone water generator when it is started up.

[0025] Furthermore, according to the present invention, when supplying ozone gas along with water to parallel ejectors to produce ozonated water, it is possible to suppress variations in the supply of ozone gas and prevent liquid that has flowed back from the ozone gas intake of the ejector from entering the ozone gas supply system.

[0026] A schematic diagram of the ozone water generator according to Embodiment 1, one aspect of the present invention. A schematic diagram of the ozone water generator according to Embodiment 2, one aspect of the present invention. A plan view showing the arrangement of the ejector in Embodiment 2. (a) A schematic diagram of the ozone water generator according to Embodiment 3, one aspect of the present invention, and (b) a plan view of the buffer tank in the ozone water generator. A schematic diagram of the ozone water generator according to Embodiment 4, one aspect of the present invention.

[0027] Embodiments of the present invention will be described below with reference to the drawings.

[0028] [Embodiment 1] The ozone water generator 1 of Embodiment 1, which is one aspect of the present invention shown in Figure 1, comprises a tank 2, a pump 3, an ejector 4, and a return line 5.

[0029] Tank 2 stores water. Tank 2 is equipped with a water supply line 21, a drain line 22, an exhaust line 23, and gas supply lines 24 and 25. Gas supply line 24 supplies gas to the gas phase in Tank 2. Gas supply line 25 supplies gas to the liquid phase in Tank 2. The water supply line 21, drain line 22, exhaust line 23, and gas supply lines 24 and 25 are each equipped with flow control valves V1, V2, V5, V6, and V7, respectively, which allow the fluid flow rate to be controlled arbitrarily.

[0030] Pump 3 is positioned below tank 2. An ozone water suction line 6 is connected to the suction side of pump 3, through which ozone water discharged from ejector 4 is supplied. A discharge line 7 is connected to the discharge side of pump 3, which supplies the ozone water to an ozone water utilization system (not shown). The discharge line 7 is equipped with a concentration meter 71 and a flow control valve V4.

[0031] The ejector 4 is positioned vertically between the tank 2 and the pump 3, and injects ozone gas drawn in from the outside into the water introduced from the tank 2 to discharge ozonated water. For example, a well-known ejector described in Patent Documents 3, 4, etc., can be used as the ejector 4. A drain line 22 from the tank 2 is connected to the inlet side of the ejector 4. An injection line 41, which supplies ozone gas from an ozone gas generator (not shown), is connected to the injection side of the ejector 4. The injection line 41 is equipped with a flow control valve V3. An ozonated water suction line 6, which is connected to the suction side of the pump 3, is connected to the outlet side of the ejector 4.

[0032] The return line 5 allows the discharged ozonated water to be returned to the tank 2. The return line 5 is equipped with a flow meter 51.

[0033] The exhaust line 23 is equipped with a pressure gauge 26 and an ozone decomposer 8. The ozone decomposer 8 decomposes the ozone contained in the gas discharged from the tank 2. A well-known ozone decomposition method, such as the pyrolysis method, activated carbon method, or ultraviolet method, is applied to the ozone decomposer 8.

[0034] An example of the operation of the ozone water generator 1 of Embodiment 1 will be described with reference to Figure 1.

[0035] First, flow control valves V1 and V2 are set to open, and flow control valves V3, V4, V5, V6, and V7 are set to closed, and water is introduced into tank 2 via the water supply line 21. Next, water is filled into the drain line 22, ejector 4, ozone water suction line 6, pump 3, discharge line 7, and return line 5, and a predetermined amount of water is stored in tank 2.

[0036] Next, the flow control valve V1 is set to closed, the pump 3 is started, and the water is circulated and supplied to the tank 2 via the drain line 22, ejector 4, ozone water suction line 6, discharge line 7, and return line 5. At this point, the flow control valve V6 is set to open as appropriate, and an inert gas (e.g., nitrogen gas) is supplied to the gas phase in the tank 2 via the gas supply line 24, thereby adjusting the internal pressure of the tank 2 as needed. Furthermore, when the internal pressure needs to be reduced, the flow control valve V5 is set to open as appropriate, and the gas in the tank 2 is discharged via the exhaust line 23. In addition, the flow control valve V7 is set to open as appropriate, and carbon dioxide (CO2) is supplied via the gas supply line 25. ２ The solution is supplied to the water in tank 2, and the water is appropriately adjusted to be acidic, thus preparing it to be water in which ozone can easily dissolve.

[0037] Subsequently, when the suction pressure of the ejector 4 reaches a pressure that allows the ozone gas in the injection line 41 to be drawn into the ejector 4, the flow control valve V3 is set to open and the ozone gas is injected into the water in the ejector 4. The ozonated water discharged from the ejector 4 is then supplied to the pump 3 via the ozonated water suction line 6. The ozonated water discharged from the pump 3 is returned to the tank 2 via the discharge line 7 and the return line 5.

[0038] Next, the ozonated water circulated to tank 2 is adjusted to a desired ozone concentration (for example, 200 mg / L or more) by automatically adjusting the opening of flow control valves V2 and V3 based on the ozone concentration and flow rate detected by the concentration meter 71 and flow meter 51. Then, flow control valve V4 is set to open and supplied to the ozonated water utilization system via the discharge line 7. At this point, flow control valve V1 is set to open as needed to replenish water in tank 2.

[0039] Subsequently, when the supply of ozonated water is stopped, the flow control valves V1, V3, and V4 are set to closed and the pump 3 is stopped. At this time, any air or ozone gas bubbles remaining in the drain line 22, ejector 4, ozonated water suction line 6, and pump 3 are transferred into the tank 2.

[0040] According to the above ozone water generator 1, the pump 3 is arranged below the tank 2 for storing water, and the ejector 4 is vertically arranged between the tank 2 and the pump 3, so that the suction side of the pump 3 can be started in a state filled with water. Although the pump 3 requires priming water, since the tank 2 is located above the pump 3, the water in the tank 2 can be directly used as priming water, and at this time, the air and ozone gas bubbles in the pump 3 and the suction side of the pump 3 (drain line 22, ejector 4, ozone water suction line 6) migrate to the tank 2. In particular, since the ejector 4 is vertically arranged between the tank 2 and the pump 3, the bubbles do not accumulate in the ejector 4 even during the operation of the ozone water generator 1. Therefore, according to the ozone water generator 1, the bubbles staying in the pump 3 are reduced and the idling of the pump 3 is suppressed, so that the operation at the start of the ozone water generator 1 is stabilized. It is clear that the present invention can also be applied to a technique for generating a gas-dissolved liquid by injecting a gas other than ozone gas into the flow of the liquid in the ejector.

[0041] [Embodiment 2] The ozone water generator 1 of Embodiment 2, which is one aspect of the present invention shown in FIG. 2, is configured such that a plurality of ejectors 4 are arranged in parallel in the aspect of Embodiment 1 to achieve the generation of a large volume of ozone water.

[0042] As illustrated in FIG. 3, the ejectors 4 are arranged at equal intervals on a concentric circle centered on the suction center of the pump 3 with the streamline of the fluid on the suction side of the pump 3 and the streamline of the working fluid of the ejector 4 being parallel. Then, the ozone water suction lines 6 on the discharge sides of the plurality of ejectors 4 are aggregated into a single ozone water suction line 6 and connected to the suction side of the pump 3, so that the pipe lengths from each ejector 4 to the pump 3 are set to be the same.

[0043] According to the ozone water generator 1 of Embodiment 2 described above, the ozone water suction lines 6 on the discharge sides of the plurality of ejectors 4 are aggregated into one ozone water suction line 6 and led to the pump 3, so that in addition to the effects of Embodiment 1, an increase in the volume of the ozone water generated by the ozone water generator 1 is realized.

[0044] [Embodiment 3] The ozone water generator 1 according to Embodiment 3, which is an aspect of the present invention shown in FIG. 4, includes a tank 2, a pump 3, an ejector 4, a return line 5, and a buffer tank 11.

[0045] The tank 2 stores water. The tank 2 includes a water supply line 21, a drainage line 22, an exhaust line 23, and gas supply lines 24 and 25. The gas supply line 24 supplies gas to the gas phase in the tank 2. The gas supply line 25 supplies gas to the liquid phase in the tank 2. Flow control valves V1, V2, V5, V6, and V7 capable of arbitrarily controlling the flow rate of the fluid are provided in the water supply line 21, the drainage line 22, the exhaust line 23, and the gas supply lines 24 and 25, respectively.

[0046] The pump 3 is disposed below the tank ⑵. An ozone water suction line 6 through which the ozone water discharged from the ejector 4 is supplied is connected to the suction side of the pump 3. A discharge line 7 for supplying the ozone water to an ozone water utilization system (not shown) is connected to the discharge side of the pump 3\. A concentration meter 71 and a flow control valve V4 are provided in the discharge line 7.

[0047] A plurality of ejectors⑷ are vertically arranged in parallel between the tank 2 and the pump 3, and inject ozone gas sucked from the buffer tank 11 into the water introduced from the tank 2 to discharge ozone water. As the ejector 4, for example, well-known ejectors described in Patent Documents 3, 4, etc. are applied. A drainage line 22 from the tank 2 is connected to the inlet side of the ejector 4. An ozone gas suction line 112 from the buffer tank 11 is connected to the injection side of the ejector 4. An ozone water suction line 6 connected to the suction side of the pump 3 is connected to the outlet side of the ejector 4.

[0048] The return line 5 enables the discharged ozone water to be returned to the tank 2. A flow meter 51 is provided in the return line 5.

[0049] The buffer tank ⑪ can store ozone gas sucked and introduced from an external gas supply system or liquid flowing back from the ozone gas suction port of the ejector 4.

[0050] The gas supply system of this embodiment is designed to draw in gas at a pressure higher than the reduced pressure created by the suction force generated by the ejector 4, and includes gas supply systems under reduced pressure. Examples of such gas supply systems include gas supply systems below atmospheric pressure. More specifically, examples include well-known ozone gas supply systems that supply ozone gas with an ozone concentration of 50% by volume or more and an oxygen concentration of less than 50% by volume. In this case, the total pressure of the ozone gas becomes a reduced pressure state of, for example, 60 kPa (abs) or less (i.e., a state with an ozone partial pressure of 30 kPa (abs) or less).

[0051] The buffer tank 11 consists of a donut-shaped tank that surrounds the ozone water suction line 6, which connects the multiple parallel ejectors 4 and the pump 3, and is coaxial with the ozone water suction line 6.

[0052] An ozone gas introduction line 111, through which ozone gas is supplied under reduced pressure from the ozone gas supply system, and an ozone gas suction line 112, which connects the buffer tank 11 to the ozone gas intake ports of the multiple parallel ejectors 4, are connected to the top of the buffer tank 11.

[0053] The ozone gas introduction line 111 is equipped with a flow control valve V3. The ozone gas suction line 112 is configured such that the piping distance between the buffer tank 11 and the suction ports of the multiple parallel ejectors 4 is equal, so that the flow resistance to the ozone gas flow is uniform.

[0054] A discharge line 110 is connected to the bottom of the buffer tank 11 to discharge the liquid that has accumulated due to backflow from the ozone gas intake of the ejector 4 and supply it to the return line 5. This discharge line 110 is equipped with a flow control valve V8 that can discharge the liquid in the tank 2 as needed based on the liquid level in the tank 2 detected by the liquid level sensor 10. The liquid level sensor 10 is not particularly limited and any well-known liquid level meter can be used as long as it can detect the liquid level in the tank 2.

[0055] The exhaust line 23 is equipped with a pressure gauge 26 and an ozone decomposer 8. The ozone decomposer 8 decomposes the ozone contained in the gas discharged from the tank 2. A well-known ozone decomposition method, such as the pyrolysis method, activated carbon method, or ultraviolet method, is applied to the ozone decomposer 8.

[0056] An example of the operation of the ozone water generator 1 of Embodiment 3 will be described with reference to Figure 4.

[0057] First, flow control valves V1 and V2 are set to open, and flow control valves V3, V4, V5, V6, and V7 are set to closed, and water is introduced into tank 2 via the water supply line 21. Next, water is filled into the drain line 22, ejector 4, ozone water suction line 6, pump 3, discharge line 7, and return line 5, and a predetermined amount of water is stored in tank 2.

[0058] Next, the flow control valve V1 is set to closed, the pump 3 is started, and the water is circulated and supplied to the tank 2 via the drain line 22, ejector 4, ozone water suction line 6, discharge line 7, and return line 5. At this point, the flow control valve V6 is set to open as appropriate, and an inert gas (e.g., nitrogen gas) is supplied to the gas phase in the tank 2 via the gas supply line 24, thereby adjusting the internal pressure of the tank 2 as needed. Furthermore, when the internal pressure needs to be reduced, the flow control valve V5 is set to open as appropriate, and the gas in the tank 2 is discharged via the exhaust line 23. In addition, the flow control valve V7 is set to open as appropriate, and carbon dioxide (CO2) is supplied via the gas supply line 25. ２ The solution is supplied to the water in tank 2, and the water is appropriately adjusted to be acidic, thus preparing it to be water in which ozone can easily dissolve.

[0059] Subsequently, when the suction pressure of the ejector 4 reaches a pressure that allows ozone gas in the ozone gas suction line 112 to be drawn into the ejector 4, the flow control valve V3 is set to open and the ozone gas is injected into the water in the ejector 4. The ozonated water discharged from the ejector 4 is then supplied to the pump 3 via the ozonated water suction line 6. The ozonated water discharged from the pump 3 is returned to the tank 2 via the discharge line 7 and the return line 5.

[0060] Next, the ozonated water circulated to tank 2 is adjusted to a desired ozone concentration (for example, 200 mg / L or more) by automatically adjusting the opening of flow control valves V2 and V3 based on the ozone concentration and flow rate detected by the concentration meter 71 and flow meter 51. Then, flow control valve V4 is set to open and supplied to the ozonated water utilization system via the discharge line 7. At this point, flow control valve V1 is set to open as needed to replenish water in tank 2.

[0061] Subsequently, when the supply of ozonated water is stopped, the flow control valves V1, V3, and V4 are set to closed and the pump 3 is stopped. At this time, any air or ozone gas bubbles remaining in the drain line 22, ejector 4, ozonated water suction line 6, and pump 3 are transferred into the tank 2.

[0062] In the ozone water generator 1 described above, the pump 3 is positioned below the water storage tank 2, and the ejector 4 is positioned vertically between the tank 2 and the pump 3, so that the suction side of the pump 3 can be started with water filled. The pump 3 requires priming, but because the tank 2 is positioned above the pump 3, the water in the tank 2 can be used directly as priming water, and at that time, air and ozone gas bubbles in the pump 3 and on the suction side of the pump 3 (drain line 22, ejector 4, ozone water suction line 6) are transferred to the tank 2. In particular, because the ejector 4 is positioned vertically between the tank 2 and the pump 3, bubbles do not accumulate in the ejector 4 even while the ozone water generator 1 is operating. Therefore, with the ozone water generator 1, bubbles remaining in the pump 3 are reduced and dry running of the pump 3 is suppressed, so the operation of the ozone water generator 1 at startup is stable.

[0063] Furthermore, since multiple ejectors 4 are arranged in parallel, and the ozone water suction lines 6 of these multiple ejectors 4 are consolidated into a single ozone water suction line 6 and led to the pump 3, a large volume of ozone water is produced by the ozone water generator 1.

[0064] Furthermore, if the water flow rate or pressure changes due to factors such as a malfunction of the pump 3, and sufficient suction force cannot be obtained to draw in the ozone gas in the buffer tank 11, the liquid that flows back from the ozone gas intake of the ejector 4 will accumulate in the buffer tank 11 via the ozone water suction line 6. This prevents the liquid from entering the ozone gas supply system and avoids adverse effects on the ozone gas supply control equipment.

[0065] The liquid accumulated in the buffer tank 11 is monitored by the liquid level sensor 10, and when a certain amount accumulates, it is discharged as appropriate by the opening and closing operation of the flow control valve V8. For example, the flow control valve V8 starts discharge when the liquid level in the buffer tank 11 reaches an upper limit that is lower than the ozone gas intake port of the ejector 4, and stops discharge when the liquid level reaches a lower limit that is higher than the intake port of the discharge line 110 in the buffer tank 11. This prevents the release of ozone gas from the buffer tank 11.

[0066] As described above, with the ozone water generator 1 of this embodiment, the ozone gas introduced from the ozone gas supply system is stored in the buffer tank 11 before being supplied to the multiple parallel ejectors 4, thus suppressing variations in the supply of ozone gas to the multiple ejectors 4. Furthermore, even if liquid flows back from the intake port of the ejector 4, it is transferred to the buffer tank 11, so the intrusion of liquid into the ozone gas supply system is suppressed, and failure of each device can be prevented.

[0067] [Embodiment 4] The ozone water generator 1 of Embodiment 4, which is one aspect of the present invention shown in Figure 5, is equipped with a buffer tank 12 that encloses the plurality of vertically arranged ejectors 4, instead of the buffer tank 11 of Embodiment 1.

[0068] The buffer tank 12 is formed into any shape at the site where the ozone water generator of this embodiment is installed, and stores ozone gas introduced by suction from the gas supply system or liquid that flows back from the ozone gas intake of the ejector 4.

[0069] The ejector 4 is enclosed within the buffer tank 12 by airtightly penetrating it, so that both ends of the ejector 4 protrude from the buffer tank 12, while the ozone gas intake of the ejector 4 is located inside the buffer tank 12.

[0070] Furthermore, an ozone gas introduction line 121 is connected to the top of the buffer tank 12 to introduce ozone gas supplied under reduced pressure from the ozone gas supply system. This ozone gas introduction line 121 is equipped with a flow control valve V3. In addition, a discharge line 120 is connected to the bottom of the buffer tank 12 to discharge the liquid that has accumulated due to backflow from the ozone gas intake of the ejector 4 and supply it to the return line 5. This discharge line 120 is equipped with a flow control valve V8 that can discharge the liquid in the buffer tank 12 as needed based on the liquid level of the buffer tank 12 detected by the liquid level sensor 10.

[0071] As is clear from the above embodiments, it is evident that the ozone water generator 1 of this embodiment provides the same effects as in embodiment 3.

[0072] 1...Ozone water generator 2...Tank, 21...Water supply line, 22...Drainage line, 23...Exhaust line, 24, 25...Gas supply line, 26...Pressure gauge 3...Pump 4...Ejector, 41...Injection line 5...Return line, 51...Flow meter 6...Ozone water suction line 7...Discharge line, 71...Concentration meter 8...Ozone decomposer 10...Liquid level sensor 11, 12...Buffer tank, 110, 120...Discharge line, 111, 121...Ozone gas introduction line, 112...Ozone gas suction line V1, V2, V3, V4, V5, V6, V7, V8...Flow control valves

Claims

1. An ozone water generating apparatus comprising: a tank for storing water; a pump positioned below the tank; an ejector positioned vertically between the tank and the pump for injecting ozone gas drawn from an external source into the water introduced from the tank to discharge ozonated water; and a return line capable of returning the discharged ozonated water to the tank.

2. The ozone water generator according to claim 1, characterized in that a plurality of ejectors are arranged in parallel.

3. The ozone water generating apparatus according to claim 2, characterized in that the ejectors are arranged at equal intervals on concentric circles centered on the suction center of the pump.

4. The ozone water generator according to claim 1, characterized in that the tank is provided with an exhaust line for discharging the gas inside the tank.

5. The ozone water generator according to claim 4, characterized in that the exhaust line is equipped with an ozone decomposer for decomposing ozone contained in the gas discharged from the tank.

6. A method for generating ozonated water using an ozonated water generating apparatus comprising a water storage tank, a pump located below the tank, and an ejector located vertically between the tank and the pump, the method comprising: a step of injecting ozone gas drawn from an external source into the water introduced from the tank into the ejector and discharging ozonated water from the ejector; and a step of returning the discharged ozonated water to the tank.

7. An ozone water generating apparatus comprising: a tank for storing water; a pump located below the tank; a plurality of parallel ejectors located vertically between the tank and the pump for injecting ozone gas into the water introduced from the tank and discharging ozonated water; a buffer tank capable of storing the ozone gas introduced by suction from an external source or the liquid that flows back from the ozone gas intake of the plurality of parallel ejectors; and a return line capable of returning the discharged ozonated water to the tank.

8. The ozone water generating apparatus according to claim 7, wherein the buffer tank is positioned between the plurality of parallel ejectors and the pump, and the ozone gas suction line connecting the buffer tank and the suction ports of the plurality of parallel ejectors has a piping distance equal to that between the buffer tank and the suction ports of the plurality of parallel ejectors.

9. The ozone water generating apparatus according to claim 8, characterized in that the buffer tank comprises a donut-shaped tank coaxially surrounding the ozone water suction line that connects the plurality of parallel ejectors and the pump.

10. The ozone water generator according to claim 7, characterized in that the buffer tank contains the plurality of parallel ejectors.

11. The ozone water generator according to claim 7, characterized in that the liquid level of the buffer tank is controlled based on the liquid level detected by a liquid level sensor provided in the buffer tank.

Images