Ozone water generator and ozone water generation method

Abstract

To reduce the amount of bubbles that accumulate in the pump of the ozone water generator, thereby suppressing dry running of the pump and stabilizing the operation of the ozone water generator during startup. [Solution] In the ozone water generator 1, the tank 2 stores water. The pump 3 is located below the tank 2. 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 ozone water. The return line 5 returns the discharged ozone water to the tank 2.

Description

Technical Field

[0001] The present invention relates to a method for generating ozone water using high-concentration ozone gas and an apparatus therefor.

Background Art

[0002] Examples of ozone water generation apparatuses that dissolve ozone gas in water to generate ozone water include ejector-type apparatuses such as those disclosed in Patent Documents 1 and 2.

[0003] In an ejector-type ozone water generation apparatus, when a negative pressure occurs in the ozone generator connected to the suction port of the ejector, the probability of a decrease in the ozone gas generation capacity and malfunctions of the ozone generator increases. Therefore, the ozone water generation apparatus 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.

[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 controlling the generated ozone concentration of an ozone generator, and controls to eliminate fluctuations in ozone concentration caused by 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 electricity with oxygen as the main raw material, and the supply pressure is normal pressure or higher.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

[0006] The conventional technology described above generates ozonated water by mixing ozone gas and water using a gas-liquid mixing device such as an ejector. The supply pressure of the ozone gas in this process is considered to be positive pressure.

[0007] On the other hand, some ozonizers (devices that generate ozone gas) maintain a negative pressure inside the device to suppress the self-decomposition of highly concentrated ozone gas. Ozone water can also be generated using conventional ejectors even with such ozonizers.

[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] 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. [Means for solving the problem]

[0010] 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.

[0011] In one aspect of the present invention, in the ozone water generator, the ejectors are arranged in parallel in a plurality of configurations.

[0012] 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.

[0013] In one aspect of the present invention, in the ozone water generating device, the tank includes an exhaust line for discharging the gas in the tank.

[0014] In one aspect of the present invention, in the ozone water generating device, the exhaust line includes an ozone decomposer for decomposing ozone contained in the gas discharged from the tank.

[0015] One aspect of the present invention is a method for generating ozone water, which is a method for generating ozone water by an ozone water generating device including a tank for storing water, a pump disposed below the tank, and an ejector vertically disposed between the tank and the pump. The method includes a process of injecting ozone gas suctioned from the outside into the water introduced from the tank to the ejector and discharging ozone water from the ejector, and a process of returning the discharged ozone water to the tank.

Effect of the Invention

[0016] According to the present invention as described above, the bubbles staying in the pump of the ozone water generating device are reduced, and the idling of the pump is suppressed, so that the operation at the time of starting the ozone water generating device is stabilized.

Brief Description of the Drawings

[0017] [Figure 1] Schematic configuration diagram of the ozone water generating device of Embodiment 1 which is one aspect of the present invention. [Figure 2] Schematic configuration diagram of the ozone water generating device of Embodiment 2 which is one aspect of the present invention. [Figure 3] Plan view showing the arrangement of the ejector of Embodiment 2.

Mode for Carrying Out the Invention

[0018] Embodiments of the present invention will be described below with reference to the drawings.

[0019] [Embodiment 1] The ozone water generator 1 of Embodiment 1, which is one aspect of the present invention shown in FIG. 1, includes a tank 2, a pump 3, an ejector 4, and a return line 5.

[0020] 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, 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. The water supply line 21, the drainage line 22, the exhaust line 23, and the gas supply lines 24, 25 are each provided with flow control valves V1, V2, V5, V6, V7 capable of arbitrarily controlling the flow rate of the fluid.

[0021] The pump 3 is arranged below the tank 2. A 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. The discharge line 7 is provided with a concentration meter 71 and a flow control valve V4.

[0022] The ejector 4 is vertically arranged between the tank 2 and the pump 3, injects ozone gas sucked from the outside into the water introduced from the tank 2, and discharges ozone water. As the ejector 4, for example, well-known ejectors described in Patent Documents 3, 4, etc. are applied. The drainage line 22 from the tank 2 is connected to the inlet side of the ejector 4. An injection line 41 through which ozone gas from an ozone gas generator (not shown) is supplied is connected to the injection side of the ejector 4. The injection line 41 is provided with a flow control valve V3. The 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 enables the discharged ozone water to be returned to the tank 2. The return line 5 is provided with a flow meter 51.

[0024] 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, the activated carbon method, or the ultraviolet method, is applied to the ozone decomposer 8.

[0025] An example of the operation of the ozone water generator 1 of Embodiment 1 will be described with reference to Figure 1.

[0026] 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 fills the drain line 22, ejector 4, suction line 6, pump 3, discharge line 7, and return line 5, and a predetermined amount of water is stored in tank 2.

[0027] 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, 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, 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 to the water in the tank 2 via the gas supply line 25, adjusting the water to the acidic side as needed to prepare water that is more likely to contain dissolved ozone.

[0028] 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 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.

[0029] 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.

[0030] Subsequently, when the supply of ozonated water is stopped, the flow control valves V1, V3, and V4 are set to closed and pump 3 is stopped. At this time, any air or ozone gas bubbles remaining in the drain line 22, ejector 4, suction line 6, and pump 3 are transferred into tank 2.

[0031] 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 already 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, 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 idling of the pump 3 is suppressed, so the operation of the ozone water generator 1 at startup is stable. It should also be noted that the present invention can be applied to techniques for generating gas-dissolved liquid by injecting gases other than ozone gas into the liquid flow in the ejector.

[0032] [Embodiment 2] The ozone water generator 1 of Embodiment 2, shown in Figure 2, which is one aspect of the present invention, generates a large volume of ozone water by arranging multiple ejectors 4 in parallel, as in the embodiment of Embodiment 1.

[0033] As illustrated in Figure 3, the ejectors 4 are arranged at equal intervals on concentric circles centered on the suction center of the pump 3, with the streamlines of the working fluid of the ejectors 4 being parallel to those of the fluid on the suction side of the pump 3. The suction lines 6 on the discharge side of multiple ejectors 4 are combined into a single suction line 6 and connected to the suction side of the pump 3, so that the length of the piping from each ejector 4 to the pump 3 is set to be the same.

[0034] According to the ozone water generator 1 of Embodiment 2 described above, the suction lines 6 on the discharge side of multiple ejectors 4 are consolidated into a single suction line 6 and led to the pump 3. In addition to the effects of Embodiment 1, this also enables a larger volume of ozone water to be produced by the ozone water generator 1. [Explanation of Symbols]

[0035] 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... Suction line 7... Discharge line, 71... Concentration meter 8…Ozone decomposer V1,V2,V3,V4,V5,V6,V7…Flow control valve

Claims

1. A tank for storing water, A pump located at the bottom of this tank, An ejector is positioned vertically between the tank and the pump and injects ozone gas drawn in from the outside into the water introduced from the tank to discharge ozonated water. A return line capable of returning the discharged ozone water to the tank, An ozone water generator characterized by having the following features.

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 ozone water using an ozone 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 process involves injecting ozone gas drawn in from an external source into the water introduced from the tank into the ejector, and discharging ozonated water from the ejector, The process of returning the discharged ozonated water to the tank, A method for generating ozonated water, characterized by having the following features.

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