Apparatus for generating gas-dissolved liquid and method for generating gas-dissolved liquid

Abstract

To prevent liquid that flows back from the gas suction port of an ejector into the gas supply system when supplying gas along with liquid to the ejector to generate a gas-dissolved liquid. [Solution] The gas-dissolved liquid generating apparatus 1 comprises a main ejector 2 that injects gas into a liquid flow and discharges a gas-dissolved liquid, a buffer tank 3 to which the gas or liquid backflowing from the gas suction section 22 of the main ejector 2 is supplied, and an auxiliary ejector 4 that communicates with the main ejector 2 and is capable of drawing the gas or liquid from the buffer tank 3.

Description

Technical Field

[0001] The present invention relates to a method for generating a gas-dissolved liquid and an apparatus therefor.

Background Art

[0002] Examples of ozone water generating 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 generating apparatus, when a negative pressure occurs in an ozone generator connected to the suction port of the ejector, the probability of a decrease in the ozone gas generation ability and malfunctions of the ozone generator increases. Therefore, the ozone water generating apparatus of Patent Document 1 provides an orifice between the ozone generator and the ejector to maintain the ozone gas generation part 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 an ozone water supply line, an ozone water circulation line, 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 during the discharge of ozone water to the supply line or the like. The ozone gas serving 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.

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, which generate ozone gas, maintain a negative pressure inside the device to suppress the self-decomposition of highly concentrated ozone gas.

[0008] However, if sufficient suction pressure cannot be obtained due to abnormalities in the supply water temperature or circulation pump, water may flow back into the ozone gas supply system and enter the ozone gas flow meter, valves, etc., potentially causing malfunction or failure of the ozone gas supply system.

[0009] In view of the above circumstances, the present invention aims to prevent liquid that has flowed back from the gas suction section of an ejector into the gas supply system when a gas is supplied to the ejector together with a liquid to generate a gas-dissolved liquid. [Means for solving the problem]

[0010] One aspect of the present invention is a gas-dissolved liquid generating apparatus comprising: a main ejector that injects gas into a liquid and discharges a gas-dissolved liquid; a buffer tank to which the gas or the liquid that has flowed back from the gas suction section of the main ejector is supplied; and an auxiliary ejector that communicates with the main ejector and is capable of drawing the gas or the liquid from the buffer tank.

[0011] In one aspect of the present invention, in the gas-dissolved liquid generating apparatus, the auxiliary ejectors are connected in series in a plurality of configurations.

[0012] In one aspect of the present invention, in the gas-dissolved liquid generating apparatus, the main ejector is enclosed within the buffer tank.

[0013] One aspect of the present invention is a gas-dissolved liquid generating apparatus in which a suction line is connected to supply the gas or liquid in the buffer tank to the gas suction section of the auxiliary ejector.

[0014] In one aspect of the present invention, in the gas-dissolved liquid generating apparatus, the main ejector and the auxiliary ejector are arranged vertically.

[0015] One aspect of the present invention relates to a method for producing a gas-dissolved liquid, comprising: a main ejector that injects gas into a liquid flow to discharge a gas-dissolved liquid; a buffer tank to which the gas or the liquid that has flowed back from the gas suction section of the main ejector is supplied; and an auxiliary ejector that communicates with the main ejector and is capable of sucking the gas or the liquid from the buffer tank, wherein the method for producing a gas-dissolved liquid is provided with the liquid to the buffer tank and the auxiliary ejector sucks the liquid from the buffer tank. [Effects of the Invention]

[0016] According to the present invention described above, when supplying a gas together with a liquid to an ejector to generate a gas-dissolved liquid, it is possible to prevent the liquid that flows back from the gas suction section of the ejector from entering the gas supply system. [Brief explanation of the drawing]

[0017] [Figure 1] A schematic cross-sectional view of a gas-dissolved liquid generating apparatus according to Embodiment 1, one aspect of the present invention. [Figure 2] A schematic cross-sectional view of a gas-dissolved liquid generating apparatus according to Embodiment 2, one aspect of the present invention. [Figure 3] A schematic cross-sectional view of a gas-dissolved liquid generating apparatus according to Embodiment 3, one aspect of the present invention. [Modes for carrying out the invention]

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

[0019] [Embodiment 1] The gas-dissolved liquid generator 1 of Embodiment 1, which is one aspect of the present invention shown in FIG. 1, includes a main ejector 2, a buffer tank 3, and an auxiliary ejector 4.

[0020] The main ejector 2 injects gas into the liquid flow, which is the working fluid introduced by the suction of a pump (not shown), and discharges the gas-dissolved liquid. As the main ejector 2, for example, well-known ejectors described in Patent Documents 3, 4, etc. are applicable. The inflow portion 21 of the main ejector 2 communicates with the discharge portion 43 of the auxiliary ejector 4. The gas suction portion 22 of the main ejector 2 communicates with the main suction line 32 to which the gas sucked and introduced from the buffer tank 3 is supplied. The discharge portion 23 of the main ejector 2 communicates with the primary-side suction line of the pump.

[0021] The buffer tank 3 is disposed directly above the gas suction portion 22 of the main ejector 2 and can store the gas sucked and introduced (supplied under reduced pressure) from an external gas supply system or the liquid flowing back from the gas suction portion 22.

[0022] The gas supply system of the present embodiment creates a reduced-pressure state by the suction force generated by the main ejector 2 and the auxiliary ejector 4, targets the suction of gas supplied at a pressure higher than that pressure, and includes a gas supply system under reduced pressure. Examples of the gas supply system include, for example, a gas supply system with a pressure less than atmospheric pressure. More specifically, for example, a well-known ozone gas supply system that supplies ozone gas with an ozone concentration of 50% by volume or more and an oxygen concentration of less than 50% by volume can be mentioned. In this case, the total pressure of the ozone gas is, for example, in a reduced-pressure state of 60 kPa(abs) or less (that is, a state where the ozone partial pressure is 30 kPa(abs) or less).

[0023] A gas introduction line 31 through which the gas is supplied under reduced pressure from the gas supply system is connected to the upper part of the buffer tank 3. The gas introduction line 31 includes a flow control valve V1. A main suction line 32 that stands upright and communicates with the gas suction portion 22 of the main ejector 2 is connected to the bottom of the buffer tank 3. Note that the main suction line 32 may be drawn in such that the suction port is always at a higher position than the liquid level in the buffer tank 3.

[0024] An auxiliary suction line 33, which communicates with the gas suction section 42 of the auxiliary ejector 4, is connected to the side of the buffer tank 3 near the bottom. The auxiliary suction line 33 is equipped with a flow control valve V2.

[0025] The flow control valve V2 may be configured to discharge liquid from the buffer tank 3 as appropriate based on the liquid level of the buffer tank 3 detected by a liquid level sensor (not shown). The liquid level sensor is not particularly limited as long as it can detect the liquid level in the buffer tank 3; any well-known liquid level meter can be used.

[0026] The auxiliary ejector 4 communicates with the main ejector 2 to draw gas or liquid from the buffer tank 3. The auxiliary ejector 4, like the main ejector 2, is fitted with the same well-known ejector. The liquid flows into the inlet 41 of the auxiliary ejector 4. The gas suction section 42 of the auxiliary ejector 4 communicates with the auxiliary suction line 33, which supplies the gas or liquid from the buffer tank 3. The discharge section 43 of the auxiliary ejector 4 communicates with the inlet 21 of the main ejector 2. Multiple auxiliary ejectors 4 may be connected in series to the main ejector 2.

[0027] Referring to the figure, an example of the operation of the gas-dissolved liquid generator 1 of Embodiment 1 will be described. Here, the working fluid (liquid) is water, the gas is the ozone gas, and the gas-dissolved liquid is ozonated water. In particular, an example of stably supplying ozonated water with an ozone concentration of 200 ppm or higher will be described.

[0028] First, the flow control valve V2 is set to closed, and water is circulated and supplied to the main ejector 2 and auxiliary ejector 4 by the suction force of the pump. Then, when the suction pressure of the main ejector 2 reaches a pressure at which the main ejector 2 can draw in the ozone gas in the buffer tank 3, the main ejector 2 draws in the ozone gas from the buffer tank 3 via the main suction line 32 and the gas suction section 22 and injects it into the water in the orifice section of the main ejector 2 to generate ozonated water. The ozonated water discharged from the discharge section 23 of the main ejector 2 is used in the ozonated water utilization system.

[0029] Here, if sufficient suction pressure cannot be obtained due to the supply water temperature or pump malfunction, and the pressure at the suction port of the main ejector 2 becomes equal to or higher than the gas supply pressure of the main suction line 32, the working fluid (water) in the main ejector 2 flows back into the buffer tank 3 via the gas suction port 22 and the main suction line 32. Next, when the liquid level in the buffer tank 3 reaches the upper limit, the flow control valve V2 opens. As a result, the fluid stored in the buffer tank 3 is supplied to the gas suction port 42 of the auxiliary ejector 4 via the auxiliary suction line 33 by the suction force of the auxiliary ejector 4. When the liquid level in the buffer tank 3 reaches the lower limit (a lower limit higher than the suction port of the auxiliary suction line 33 or a liquid level where the liquid level in the buffer tank 3 is approximately zero), the flow control valve V2 closes, and the discharge stops. This prevents the backflow of the working fluid from the gas suction port 42 of the auxiliary ejector 4 to the buffer tank 3.

[0030] As described above, according to this embodiment, when the flow velocity of the working fluid decreases or stops, the working fluid that flows back from the gas suction section 22 of the main ejector 2 is sucked in by the auxiliary ejector 4 upstream of the main ejector 2, thereby preventing the working fluid from entering the gas supply system. Therefore, it is possible to prevent malfunctions and failures of the gas supply system that occur when sufficient suction pressure cannot be obtained due to abnormalities in the supply water temperature or circulation pump, etc., and the working fluid flows back into the gas flow meter, valve, etc.

[0031] Furthermore, since the liquid stored in the buffer tank 3 contains dissolved gas, this liquid can be supplied to the auxiliary ejector 4 and used as the working fluid for the main ejector 2 to generate a gas-dissolved liquid with a high concentration of dissolved gas. Moreover, by connecting multiple auxiliary ejectors 4 in series, a high-concentration gas-dissolved liquid can be generated rapidly.

[0032] In this embodiment, the liquid level sensor and flow control valve V2 are not essential elements. If liquid flows back from either the gas suction section 22 of the main ejector 2 or the gas suction section 42 of the auxiliary ejector 4, the main ejector 2 or the auxiliary ejector 4, which is not experiencing backflow, will suck up the liquid.

[0033] [Embodiment 2] The gas-dissolved liquid generating apparatus 1 of Embodiment 2, which is one aspect of the present invention shown in Figure 2, is equipped with a buffer tank 5 that horizontally encloses the main ejector 2, instead of the buffer tank 3 of Embodiment 1.

[0034] The buffer tank 5 is formed into any shape at the site where the ozone water generator of this embodiment is installed, and is capable of storing gas introduced by suction from the gas supply system or liquid that flows back from the gas suction section 22 of the main ejector 2.

[0035] The main ejector 2 penetrates the buffer tank 5 and is enclosed within it, so that both ends of the main ejector 2 protrude airtightly from the buffer tank 5, while the gas suction portion 22 of the main ejector 2 is housed inside the buffer tank 5.

[0036] A gas introduction line 51 is connected to the top of the buffer tank 5 to introduce ozone gas supplied under reduced pressure from the gas supply system. This gas introduction line 51 is equipped with a flow control valve V1. A suction line 52 is connected to the bottom of the buffer tank 5 to supply the gas or liquid from the main ejector 2 to the gas suction section 42 of the auxiliary ejector 4.

[0037] Referring to the figure, an example of the operation of the gas-dissolved liquid generator 1 of Embodiment 2 will be described. Here, the working fluid is water, the gas is the ozone gas, and the gas-dissolved liquid is ozonated water. Similar to Embodiment 1, an example of stably supplying ozonated water with an ozone concentration of 200 ppm or higher will be described.

[0038] The suction force of the pump circulates and supplies water to the main ejector 2 and the auxiliary ejector 4. Subsequently, when the suction pressure of the main ejector 2 and the auxiliary ejector 4 reaches a pressure at which the main ejector 2 can draw in the ozone gas in the buffer tank 5, the auxiliary ejector 4 draws in the ozone gas in the buffer tank 5 via the suction line 52 and the gas suction section 42 and injects it into the water in the orifice section of the auxiliary ejector 4 to generate ozonated water. Next, the main ejector 2 draws in the ozone gas in the buffer tank 5 via the gas suction section 22 and injects it into the ozonated water in the orifice section of the main ejector 2. The ozonated water discharged from the discharge section 23 of the main ejector 2 is then used in the ozonated water utilization system.

[0039] Here, if the suction pressure of the main ejector 2 becomes equal to or lower than the pressure of the gas flowing through the gas supply piping for any reason, the liquid in the main ejector 2 flows back into the buffer tank 5 via the gas suction section 22. At this time, the auxiliary ejector 4 draws the liquid in the buffer tank 5 together with ozone gas via the suction line 52 and the gas suction section 42 and injects it into the working fluid (water) in the orifice of the auxiliary ejector 4. In this way, the liquid in the buffer tank 5 is quickly returned to the main ejector 2 and the auxiliary ejector 4 via the suction line 52.

[0040] According to the above embodiment, it is clear that the same effects as in Embodiment 1 can be obtained. In particular, in this embodiment, since the gas is dissolved in the liquid in multiple layers, a gas-dissolved liquid with a high concentration of dissolved gas can be produced in a short time.

[0041] Furthermore, although the main ejector 2 contained within the buffer tank 5 is positioned downstream of the auxiliary ejector 4, the same effect can be obtained by positioning it upstream of the auxiliary ejector 4. Moreover, the effect of this embodiment is further enhanced by connecting multiple auxiliary ejectors 4 in series.

[0042] [Embodiment 3] The gas-dissolved liquid generating apparatus 1 of Embodiment 3, shown in Figure 2, is similar in configuration to Embodiment 2, except that a main ejector 2 and an auxiliary ejector 4 are vertically arranged in series and the working fluid (liquid) is supplied from above.

[0043] It is clear that the same effects as in Embodiment 2 can be obtained with this embodiment. In particular, by having the working fluid flow from above to below the main ejector 2 and auxiliary ejector 4 which are connected in series, bubbles will not accumulate near the pump located below the main ejector 2 and auxiliary ejector 4 when the gas-dissolved liquid generator 1 is stopped. Therefore, idling of the pump when the gas-dissolved liquid generator 1 is started is suppressed, and the initial operation of the gas-dissolved liquid generator 1 is stabilized.

[0044] Furthermore, the same effect can be obtained even if the main ejector 2 enclosed in the buffer tank 5 is positioned upstream of the auxiliary ejector 4, as in Embodiment 2. Moreover, the effect of this embodiment is further enhanced by connecting multiple auxiliary ejectors 4 in series. [Explanation of Symbols]

[0045] 1...Gas-dissolved liquid generation device 2...Main ejector, 21...Inlet, 22...Gas suction, 23...Discharge 3...Buffer tank, 31...Gas introduction line, 32...Main suction line, 33...Auxiliary suction line, V1, V2...Flow control valves 4...Auxiliary ejector, 41...Inlet, 42...Gas suction, 43...Discharge 5...Buffer tank, 51...Gas introduction line, 52...Suction line

Claims

1. A main ejector that injects gas into a liquid flow and discharges a gas-dissolved liquid, A buffer tank to which the gas or the liquid that has flowed back from the gas suction section of the main ejector is supplied, An auxiliary ejector, which communicates with the main ejector and is capable of drawing the gas or liquid from the buffer tank, A gas-dissolved liquid generating apparatus characterized by comprising the following:

2. The gas-dissolved liquid generating apparatus according to claim 1, characterized in that a plurality of auxiliary ejectors are connected in series.

3. The gas-dissolved liquid generating apparatus according to claim 1, characterized in that the main ejector is enclosed within the buffer tank.

4. The gas-dissolved liquid generating apparatus according to claim 3, further comprising a suction line for supplying the gas or liquid in the buffer tank to the gas suction section of the auxiliary ejector.

5. The gas-dissolved liquid generating apparatus according to claim 1, characterized in that the main ejector and the auxiliary ejector are arranged vertically.

6. A method for producing a gas-dissolved liquid using a gas-dissolved liquid generating apparatus comprising: a main ejector that injects gas into a liquid flow to discharge a gas-dissolved liquid; a buffer tank to which the gas or the liquid backflowing from the gas suction section of the main ejector is supplied; and an auxiliary ejector that communicates with the main ejector and is capable of drawing the gas or the liquid from the buffer tank, wherein The process by which the liquid is supplied to the buffer tank, The process by which the auxiliary ejector draws the liquid from the buffer tank, A method for producing a gaseous dissolved liquid, characterized by having the following:

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