Ozone water generator

Abstract

To suppress variations in the supply of ozone gas when ozone water is generated by supplying ozone gas together with water to parallel ejectors, and to prevent liquid flowing back from the ozone gas intake ports of the ejectors from entering an ozone gas supply system. [Solution] The ozone water generating device 1 comprises a tank 2 for storing water, a pump 3 arranged below the tank 2, multiple parallel ejectors 4 arranged vertically between the tank 2 and the pump 3 for injecting ozone gas into the water introduced from the tank 2 and discharging ozone water, a buffer tank 12 capable of storing ozone gas sucked in from the outside or liquid that flows back from the ozone gas suction port of the ejector 4, and a return line 5 capable of returning the discharged ozone water to the tank 2.

Description

[Technical Field]

[0001] The present invention relates to an ozone water generating apparatus using ozone gas. [Background technology]

[0002] Examples of ozone water generating devices that generate ozone water by dissolving ozone gas in water include ejector-type devices as disclosed in Patent Documents 1 and 2.

[0003] In an ejector-type ozone water generator, if negative pressure occurs in the ozone generator connected to the suction port of the ejector, the ozone gas generation capacity decreases and the probability of malfunctioning 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 a positive pressure in the ozone gas generation section of the ozone generator, thereby supplying ozone gas to the ejector under the same pressure.

[0004] The ozonated water supply system of Patent Document 2 includes an ozonated water supply line, an ozonated water circulation line, an ozone concentration sensor, and a controller for the ozone concentration generated by the ozone generator, and controls the ozone concentration to eliminate fluctuations in the ozone concentration due to the release of ozonated water into the supply line, etc. Ozone gas, which is the raw material for ozonated water, is generated by an electric discharge ozonizer that uses oxygen as the main raw material and generates ozone gas by electric discharge, and the supply pressure is above atmospheric pressure. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 4746515 [Patent Document 2] Patent No. 7041466 [Patent Document 3] Patent No. 4186551 [Patent Document 4] Patent No. 4118185 Summary of the Invention [Problem to be solved by the invention]

[0006] In the above-mentioned conventional technology, ozone water is produced by mixing ozone gas and water using a gas-liquid mixing device such as an ejector. At this time, the supply pressure of the ozone gas is considered to be positive.

[0007] On the other hand, some ozone gas generating devices (ozonizers) maintain ozone gas at negative pressure within the device in order to suppress the self-decomposition of highly concentrated ozone gas, etc. However, even with such ozonizers, it is possible to generate ozone water using a conventional ejector.

[0008] In the above-mentioned conventional ozone water generation technology, one possible method for achieving a large-volume supply of ozone water of several L / min or more, which is commonly used, by applying it to an ozonizer that holds ozone gas at negative pressure is to connect ejectors in parallel to increase the flow rate.

[0009] However, when sufficient suction pressure cannot be obtained from the parallel ejectors due to variations in the supply water pressure or an abnormality in the circulation pump, water may flow back into the ozone gas supply system and flow into the ozone gas flow meter, valves, etc., which may cause the ozone gas supply system to malfunction or break down.

[0010] In view of the above circumstances, an object of the present invention is to suppress variations in the supply of ozone gas when ozone water is generated by supplying ozone gas together with water to parallel ejectors, and to prevent liquid that has flowed back from the ozone gas suction port of the ejector from entering the ozone gas supply system. [Means for solving the problem]

[0011] One aspect of the present invention is an ozone water generating device comprising a tank for storing water, a pump arranged below the tank, multiple parallel ejectors arranged vertically between the tank and the pump for injecting ozone gas into the water introduced from the tank and discharging ozone water, a buffer tank capable of storing the ozone gas sucked in from the outside or liquid that flows back from the ozone gas suction ports of the multiple parallel ejectors, and a return line capable of returning the discharged ozone water to the tank.

[0012] In one aspect of the present invention, in the ozone water generating apparatus, the buffer tank is arranged between the multiple parallel ejectors and the pump, and the ozone gas suction line connecting the buffer tank and the suction ports of the multiple parallel ejectors has an equal piping distance between the buffer tank and the suction ports of the multiple parallel ejectors.

[0013] In one aspect of the present invention, in the ozone water generating apparatus, the buffer tank is a donut-shaped tank that is coaxial with the ozone water suction line connecting the multiple parallel ejectors and the pump and surrounds the ozone water suction line.

[0014] In one aspect of the present invention, in the ozone water generation apparatus, the buffer tank contains the plurality of ejectors arranged in parallel.

[0015] In one aspect of the present invention, in the ozone water generation apparatus, the liquid level in the buffer tank is controlled based on the liquid level detected by a liquid level sensor provided in the buffer tank. [Effects of the Invention]

[0016] According to the present invention, when ozone gas is supplied to parallel ejectors together with water to generate ozone water, it is possible to suppress variations in the supply of ozone gas and to prevent liquid that has flowed back from the ozone gas suction port of the ejector from entering the ozone gas supply system. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1A is a schematic diagram of an ozone water generation apparatus according to a first embodiment of the present invention, and FIG. 1B is a plan view of a buffer tank in the ozone water generation apparatus. [Figure 2] FIG. 1 is a schematic diagram showing the configuration of an ozone water generating apparatus according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0019] [Embodiment 1] The ozone water generating apparatus 1 according to the first embodiment of the present invention shown in FIG. 1 includes a tank 2, a pump 3, an ejector 4, a return line 5, and a buffer tank 11.

[0020] 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. 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 that can arbitrarily control the flow rate of the fluid.

[0021] The pump 3 is disposed below the tank 2. An ozone water suction line 6, to 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, to which the ozone water is supplied to an ozone water utilization system (not shown), is connected to the discharge side of the pump 3. The discharge line 7 is equipped with a concentration meter 71 and a flow control valve V4.

[0022] A plurality of ejectors 4 are arranged vertically in parallel between the tank 2 and the pump 3, and inject ozone gas sucked from a buffer tank 11 into the water introduced from the tank 2, thereby discharging ozone water. As the ejector 4, for example, a well-known ejector described in Patent Documents 3 and 4 is 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.

[0023] The return line 5 allows the discharged ozone water to be returned to the tank 2. The return line 5 is provided with a flow meter 51.

[0024] The buffer tank 11 is capable of storing ozone gas sucked in from an external gas supply system or liquid that flows back from the ozone gas suction port of the ejector 4.

[0025] The gas supply system of this embodiment creates a reduced pressure state by the suction force generated by the ejector 4, and is intended to suck in gas supplied at a pressure equal to or higher than that pressure, and includes a gas supply system at reduced pressure. Examples of the gas supply system include a gas supply system at pressures lower than 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 is reduced to, for example, 60 kPa (abs) or less (i.e., an ozone partial pressure of 30 kPa (abs) or less).

[0026] The buffer tank 11 is a donut-shaped tank that surrounds the ozone water suction line 6 coaxially with the ozone water suction line 6 that connects the plurality of parallel ejectors 4 and the pump 3 .

[0027] An ozone gas introduction line 111 through which ozone gas is supplied at reduced pressure from an ozone gas supply system, and an ozone gas suction line 112 connecting the buffer tank 11 with the ozone gas suction ports of the multiple parallel ejectors 4 are connected to the upper part of the buffer tank 11.

[0028] The ozone gas introduction line 111 is equipped with a flow control valve V3. The ozone gas suction line 112 is set so that the piping distances between the buffer tank 11 and the suction ports of the plurality of parallel ejectors 4 are equal to each other so that the flow resistance to the ozone gas flow is uniform.

[0029] A discharge line 110 is connected to the bottom of the buffer tank 11, which appropriately discharges the accumulated liquid that flows back from the ozone gas suction port of the ejector 4 and supplies it to the return line 5. The discharge line 110 is provided with a flow control valve V8 that can appropriately discharge the liquid in the tank 2 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 as long as it can detect the liquid level in the tank 2, and a well-known liquid level meter can be used.

[0030] The exhaust line 23 is equipped with a pressure gauge 26 and an ozone decomposer 8. The ozone decomposer 8 decomposes ozone contained in the gas discharged from the tank 2. The ozone decomposer 8 employs a well-known ozone decomposition method, such as a thermal decomposition method, an activated carbon method, or an ultraviolet method.

[0031] An example of the operation of the ozone water production apparatus 1 of the first embodiment will be described with reference to FIG.

[0032] First, flow control valves V1 and V2 are set to open, and flow control valves V3, V4, V5, V6, and V7 are set to close, and water is introduced into tank 2 via water supply line 21. Next, water is filled into drain line 22, ejector 4, ozone water suction line 6, pump 3, discharge line 7, and return line 5, and further, a predetermined amount of water is stored in tank 2.

[0033] Next, flow control valve V1 is set to close, pump 3 is started, and the water is circulated and supplied to tank 2 via drain line 22, ejector 4, ozone water suction line 6, discharge line 7, and return line 5. Here, flow control valve V6 is set to open as appropriate, and an inert gas (e.g., nitrogen gas) is supplied to the gas phase within tank 2 via gas supply line 24, thereby appropriately adjusting the internal pressure of tank 2. Furthermore, when the internal pressure is to be reduced, flow control valve V5 is set to open as appropriate, and the gas within tank 2 is discharged via exhaust line 23. Furthermore, flow control valve V7 is set to open as appropriate, and carbon dioxide gas (CO2) is supplied to the water within tank 2 via gas supply line 25, appropriately adjusting the water to the acidic side, thereby preparing water into which ozone is more likely to dissolve.

[0034] Thereafter, when the suction pressure of the ejector 4 reaches a pressure at which the ozone gas in the ozone gas suction line 112 can be sucked 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. Then, the ozone water discharged from the ejector 4 is supplied to the pump 3 via the ozone water suction line 6. The ozone water discharged from the pump 3 is returned to the tank 2 via the discharge line 7 and the return line 5.

[0035] Next, the ozone concentration of the ozonated water circulated and supplied to tank 2 is adjusted to a desired concentration (e.g., an ozone concentration of 200 mg / L or more) by automatically adjusting the openings of flow control valves V2 and V3 based on the ozone concentration and flow rate detected by concentration meter 71 and flow meter 51. Then, flow control valve V4 is set to open, and the ozonated water is supplied to the ozonated water utilization system via discharge line 7. Here, flow control valve V1 is set to open at an appropriate time, and water is replenished into tank 2.

[0036] Thereafter, when the supply of ozone water is stopped, the flow control valves V1, V3, and V4 are closed and the pump 3 is stopped. At this time, air and ozone gas bubbles remaining in the drainage line 22, the ejector 4, the ozone water suction line 6, and the pump 3 move into the tank 2.

[0037] According to the ozone water generator 1 described above, the pump 3 is disposed below the tank 2 that stores water, and the ejector 4 is disposed vertically between the tank 2 and the pump 3, allowing the pump 3 to be started with its suction side filled with water. The pump 3 requires priming, but since the tank 2 is located above the pump 3, the water in the tank 2 can be used as priming water. At this time, air and ozone gas bubbles within the pump 3 and its suction side (the drain line 22, the ejector 4, and the ozone water suction line 6) are transferred to the tank 2. In particular, since the ejector 4 is disposed vertically between the tank 2 and the pump 3, the bubbles do not accumulate within the ejector 4 even during operation of the ozone water generator 1. Therefore, the ozone water generator 1 reduces the amount of bubbles remaining within the pump 3 and suppresses idling of the pump 3, stabilizing operation of the ozone water generator 1 upon startup.

[0038] In addition, 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, the ozone water generation device 1 can generate a large volume of ozone water.

[0039] Furthermore, if the flow rate or pressure of the water changes due to factors such as a malfunction of the pump 3 and sufficient suction force cannot be obtained to suck the ozone gas from the buffer tank 11, the liquid that flows back from the ozone gas suction port 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 prevents it from adversely affecting the ozone gas supply control equipment.

[0040] The liquid level accumulated in the buffer tank 11 is monitored by a liquid level sensor 10, and when a certain amount of liquid accumulates, the liquid is discharged appropriately by opening and closing the flow control valve V8. For example, the flow control valve V8 starts the discharge when the liquid level in the buffer tank 11 reaches an upper limit liquid level that is lower than the ozone gas suction port of the ejector 4, and stops the discharge when the liquid level reaches a lower limit liquid level that is higher than the suction port of the discharge line 110 in the buffer tank 11. This prevents the release of ozone gas from the buffer tank 11.

[0041] As described above, according to the ozone water generator 1 of this embodiment, ozone gas introduced from the ozone gas supply system is retained in the buffer tank 11 before being supplied to the multiple parallel ejectors 4, thereby reducing variations in the supply of ozone gas to the multiple ejectors 4. Furthermore, even if liquid flows back from the suction port of the ejector 4, it moves to the buffer tank 11, thereby preventing the liquid from entering the ozone gas supply system and preventing breakdowns in each device.

[0042] [Embodiment 2] The ozone water generation apparatus 1 of embodiment 2, which is one aspect of the present invention shown in Figure 2, is equipped with a buffer tank 12 containing the multiple ejectors 4 arranged vertically in parallel, instead of the buffer tank 11 of embodiment 1.

[0043] The buffer tank 12 is formed into any shape at the site where the ozone water generation apparatus of this embodiment is installed, and stores ozone gas sucked in from the gas supply system or liquid that flows back from the ozone gas suction port of the ejector 4.

[0044] The ejector 4 penetrates the buffer tank 12 airtightly and is contained in the buffer tank 12, so that both ends of the ejector 4 protrude from the buffer tank 12 while the ozone gas intake port of the ejector 4 is contained within the buffer tank 12.

[0045] An ozone gas inlet line 121, which introduces ozone gas supplied at reduced pressure from an ozone gas supply system, is connected to the top of the buffer tank 12. This ozone gas inlet line 121 is equipped with a flow control valve V3. Furthermore, a discharge line 120 is connected to the bottom of the buffer tank 12, which appropriately discharges accumulated liquid that flows back from the ozone gas suction port of the ejector 4 and supplies the liquid to the return line 5. This discharge line 120 is equipped with a flow control valve V8 that can appropriately discharge the liquid in the buffer tank 12 based on the liquid level in the buffer tank 12 detected by the liquid level sensor 10.

[0046] As is clear from the above aspects, it is clear that the ozone water production apparatus 1 of this embodiment can provide the same effects as those of the first embodiment. [Explanation of symbols]

[0047] 1...Ozone water generator 2...tank, 21...water supply line, 22...drainage line, 23...exhaust line, 24, 25...gas supply lines, 26...pressure gauge 3. Pump 4...Ejector 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...exhaust lines, 111, 121...ozone gas introduction lines, 112...ozone gas suction line V1,V2,V3,V4,V5,V6,V7,V8…Flow control valve

Claims

1. A tank for storing water; a pump disposed below the tank; a plurality of parallel ejectors arranged vertically between the tank and the pump, for injecting ozone gas into the water introduced from the tank and discharging ozone water; a buffer tank capable of storing the ozone gas sucked and introduced from the outside or a liquid that flows back from the ozone gas suction ports of the plurality of parallel ejectors; a return line capable of returning the discharged ozone water to the tank; An ozone water generating apparatus comprising:

2. the buffer tank is disposed between the plurality of parallel ejectors and the pump; 2. The ozone water generating apparatus according to claim 1, wherein the ozone gas suction line connecting the buffer tank and the suction ports of the plurality of parallel ejectors has an equal piping distance between the buffer tank and the suction ports of the plurality of parallel ejectors.

3. The ozone water generating apparatus according to claim 2, characterized in that the buffer tank is a donut-shaped tank that is coaxial with the ozone water suction line connecting the multiple parallel ejectors and the pump and surrounds the ozone water suction line.

4. 2. The ozone water generating apparatus according to claim 1, wherein the buffer tank contains the plurality of ejectors arranged in parallel.

5. 2. The ozone water generating apparatus according to claim 1, wherein the liquid level in the buffer tank is controlled based on the liquid level detected by a liquid level sensor provided in the buffer tank.

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