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

Abstract

This prevents liquid that flows back from the gas suction port of the 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 pump 2 for sucking liquid, an ejector 3 positioned on the primary side of the pump 2 for injecting gas into the flow of the liquid introduced by the suction to discharge a gas-dissolved liquid, a buffer tank 4 capable of storing the gas introduced by suction or the liquid that flows back from the gas suction section of the ejector, and a discharge line 5 for discharging the liquid from the buffer tank 4 to the primary side suction line 7 of the pump 2.

Description

Technical Field

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

Background Art

[0002] Examples of ozone water generating apparatuses for dissolving 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 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 generating 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 due to 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 oxygen as a 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 pump for sucking up liquid; an ejector disposed on the primary side of the pump for injecting gas into the flow of liquid introduced by the suction to discharge a gas-dissolved liquid; a buffer tank capable of storing the gas introduced by suction or the liquid that flows back from the gas suction section of the ejector; and a discharge line for discharging the liquid from the buffer tank to the primary side suction line of the pump.

[0011] One aspect of the present invention is a gas-dissolved liquid generating apparatus in which the buffer tank is positioned directly above the horizontally positioned gas suction section, and an upright gas suction line communicating with the gas suction section is drawn into the buffer tank from the bottom of the buffer tank, and the discharge line is connected to the side surface near the bottom of the buffer tank.

[0012] One aspect of the present invention is a gas-dissolved liquid generating apparatus in which the discharge line includes a valve that discharges the liquid based on the liquid level of the liquid in the buffer tank, the valve starts discharge when the liquid level reaches an upper limit liquid level lower than the gas suction port in the buffer tank, and stops discharge when the liquid level reaches a lower limit liquid level higher than the suction port of the discharge line in the buffer tank.

[0013] In one aspect of the present invention, in the gas-dissolved liquid generating apparatus, the ejector is housed in the buffer tank.

[0014] One aspect of the present invention is a gas-dissolved liquid generating apparatus in which the discharge line includes a valve that discharges the liquid based on the liquid level of the liquid in the buffer tank, the valve starts discharge when the liquid level reaches an upper limit liquid level lower than the gas suction section, and stops discharge when the liquid level reaches a lower limit liquid level higher than the suction port of the discharge line in the buffer tank.

[0015] One aspect of the present invention is a method for producing a gas-dissolved liquid using a gas-dissolved liquid generating apparatus comprising: a pump for sucking up a liquid; an ejector disposed on the primary side of the pump for injecting gas into the liquid introduced by the suction to discharge a gas-dissolved liquid; and a buffer tank capable of storing the gas introduced by suction from the outside or the liquid that has backflowed from the gas suction section of the ejector, the method comprising: a process in which the liquid that has backflowed from the gas suction section is stored in the buffer tank; and a process in which the liquid is discharged from the buffer tank to the primary side suction line of the pump on the discharge side of the ejector. [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] Schematic cross-sectional view of the gas-dissolved liquid generator of Embodiment 1, which is one aspect of the present invention. [Figure 2] Schematic cross-sectional view of the gas-dissolved liquid generator of Embodiment 2, which is one aspect of the present invention. [Figure 3] Schematic cross-sectional view of the gas-dissolved liquid generator of Embodiment 3, which is one aspect of the present invention.

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 gas-dissolved liquid generator 1 of Embodiment 1, which is one aspect of the present invention shown in FIG. 1, includes a pump 2, an ejector 3, a buffer tank 4, and a discharge line 5.

[0020] The pump 2 sucks the liquid from the tank 6 storing the liquid. The suction side of the pump 2 communicates with the primary-side suction line 7 of the pump 2 to which the gas-dissolved liquid is supplied from the ejector 3. The discharge side of the pump 2 branches from a supply line (not shown) that supplies the gas-dissolved liquid to the utilization system of the gas-dissolved liquid and communicates with a return line 8 that returns a part of the gas-dissolved liquid to the tank 6.

[0021] The ejector 3 is disposed between the tank 6 and the pump 2, injects the gas sucked from the buffer tank 4 into the flow of the liquid introduced as the working fluid from the tank 6, and discharges the gas-dissolved liquid. As the ejector 3, for example, well-known ejectors described in Patent Documents 3, 4, etc. are applied. The inflow portion 31 of the ejector 3 communicates with the inflow line 9 to which the liquid from the tank 6 is supplied. The gas suction portion 32 of the ejector 3 communicates with the gas suction line 10 to which the gas sucked and introduced from the buffer tank 4 is supplied. The discharge portion 33 of the ejector 3 communicates with the primary-side suction line 7 of the pump 2.

[0022] The buffer tank 4 is capable of storing the gas introduced by suction (reduced pressure supply) from an external gas supply system or the liquid that flows back from the gas suction section 32 of the ejector 3.

[0023] 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 3, 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 where the ozone partial pressure is 30 kPa (abs) or less).

[0024] A gas introduction line 11, through which the gas is supplied under reduced pressure from the gas supply system, is connected to the top of the buffer tank 4. The gas introduction line 11 is equipped with a flow control valve V1. A gas suction line 10, which communicates with the gas suction section 32 of the ejector 3, is connected to the side of the buffer tank 4 near the top. A discharge line 5 is connected to the bottom of the buffer tank 4.

[0025] The discharge line 5 discharges the liquid from the buffer tank 4 to the primary suction line 7 of the pump 2. The discharge line 5 is equipped with a flow control valve V2 that can appropriately discharge the liquid in the buffer tank 4 based on the liquid level of the buffer tank 4 detected by the liquid level sensor 12. The liquid level sensor 12 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 buffer tank 4.

[0026] Referring to Figure 1, 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 aforementioned 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.

[0027] First, a predetermined amount of water is stored in the tank 6. Next, the pump 2 is started, and the water is circulated and supplied to the tank 6 via the inflow line 9, the ejector 3, the primary suction line 7, and the return line 8. Subsequently, when the suction pressure of the ejector 3 reaches a pressure that can draw the ozone gas in the buffer tank 4 into the ejector 3, the ozone gas is supplied to the gas suction line 10 and the gas suction section 32 of the ejector 3, and is further injected into the water flowing through the orifice section of the ejector 3. The ozonated water discharged from the discharge section 33 of the ejector 3 is then supplied to the pump 2 via the primary suction line 7. The ozonated water discharged from the pump 2 is returned to the tank 6 via the return line 8.

[0028] The ozonated water circulated to tank 6 is automatically supplied via the flow control valve V1, with the opening degree adjusted based on the ozone concentration and flow rate. Ozone gas is then injected from the ozone gas supply system into the water circulating in ejector 3 via the gas introduction line 11, buffer tank 4, and gas suction line 10. The ozonated water, with its ozone concentration adjusted to the desired level (for example, 200 mg / L or higher), is then supplied to the ozonated water utilization system via the supply line branched from the return line 8. Water is then replenished to tank 6 from an external source as needed.

[0029] Here, if sufficient suction pressure cannot be obtained due to the supply water temperature or a malfunction of pump 2, and the pressure at the suction part of ejector 3 becomes equal to or higher than the gas supply pressure of gas suction line 10, the liquid will flow back into buffer tank 4 via gas suction part 32 and gas suction line 10. Next, when the liquid level in buffer tank 4 reaches the upper limit liquid level (the upper limit liquid level lower than the suction port of gas suction line 10), the flow control valve V2 opens. As a result, the fluid accumulated in buffer tank 4 is discharged to the primary side suction line 7 via the discharge line 5 by the suction force of pump 2. Then, when the liquid level in buffer tank 4 reaches the lower limit liquid level (the lower limit liquid level higher than the suction port of discharge line 5), the flow control valve V2 closes, and the discharge stops. This prevents backflow of water from the gas suction part 32 of ejector 3 to the gas suction line 10, buffer tank 4, and discharge line 5 due to the suction pressure of pump 2.

[0030] As described above, the gas-dissolved liquid generating apparatus 1 of this embodiment can 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 (liquid) flows back into the gas supply system and flows into gas flow meters, valves, etc. In particular, since the working fluid that flows back from the gas suction section 32 of the ejector 3 into the gas suction line 10 is discharged into the primary side suction line 7 of the pump 2, the amount of working fluid that blocks the airway of the gas suction line 10 can be minimized.

[0031] [Embodiment 2] In the gas-dissolved liquid generating apparatus 1 of Embodiment 2 of the present invention shown in Figure 2, a buffer tank 4 is positioned directly above the gas suction section 32 of a horizontally arranged ejector 3. A vertical gas suction line 10, communicating with the gas suction section 32 of the ejector 3, is drawn into the buffer tank 4 from the bottom of the buffer tank 4. A discharge line 5 is also connected to the side of the buffer tank 4 near the bottom. Except for the above configuration, this embodiment is the same as Embodiment 1.

[0032] As is clear from the above embodiments, the gas-dissolved liquid generating apparatus 1 of this embodiment provides the same effects as in Embodiment 1. In particular, the gas suction line 10 between the buffer tank 4 and the ejector 3 has a shorter flow path than the discharge line 5 between the buffer tank 4 and the primary side suction line 7, and the suction force of the ejector 3 is higher than the suction force of the pump 2. Therefore, even when the buffer tank 4 is empty and the flow control valve V2 of the discharge line 5 is open on the primary side suction line 7 of the pump 2, the balance between the suction pressure of the pump 2 and the suction pressure of the ejector 3 is less likely to be disrupted. Thus, the gas-dissolved liquid generated by injecting gas into a liquid can be supplied stably.

[0033] [Embodiment 3] The gas-dissolved liquid generating apparatus 1 of Embodiment 3, shown in Figure 2, is identical to Embodiment 1 except that it is equipped with a buffer tank 4 that airtightly houses an ejector 3 arranged vertically or horizontally, instead of the buffer tank 4 of Embodiment 1.

[0034] The buffer tank 4 of this embodiment can be formed into any shape at the site where the gas-dissolved liquid generating device 1 is installed, and can store the gas supplied under reduced pressure from the gas supply system or the liquid that flows back from the gas suction section 32 of the ejector 3.

[0035] Furthermore, a gas introduction line 11 is connected to the top of the buffer tank 4 to introduce ozone gas supplied under reduced pressure from the ozone gas supply system. This gas introduction line 11 is equipped with a flow control valve V1. In addition, a discharge line 5 is connected to the bottom of the buffer tank 4 to discharge the liquid that has accumulated due to backflow from the gas suction section 32 of the ejector 3 and supply it to the primary suction line 7 of the pump 2. This discharge line 5 is equipped with a flow control valve V2 that can discharge the liquid in the buffer tank 4 as needed based on the liquid level of the buffer tank 4 detected by the liquid level sensor 12.

[0036] As is clear from the above embodiments, it is evident that the gas-dissolved liquid generating apparatus 1 of this embodiment provides the same effects as in Embodiment 1.

[0037] In other words, when ozonated water, which is a gaseous dissolved liquid, is generated, ozone gas is drawn in from the gas introduction line 11, supplied to the gas suction section 32 of the ejector 3 via the buffer tank 4, and injected into the water flowing through the orifice section of the ejector 3 to generate ozonated water. The ozonated water discharged from the discharge section 33 of the ejector 3 is supplied to the pump 2 via the primary suction line 7.

[0038] Here, if sufficient suction pressure cannot be obtained due to the supply water temperature or a malfunction of pump 2, the liquid that flows back from the gas suction section 32 of ejector 3 accumulates at the bottom of buffer tank 4. Next, when the liquid level in buffer tank 4 reaches the upper limit level (an upper limit level lower than the gas suction section 32 of ejector 3), the flow control valve V2 opens. As a result, the liquid accumulated in buffer tank 4 is discharged to the primary side suction line 7 via the discharge line 5 by the suction force of pump 2. Then, when the liquid level in buffer tank 4 reaches the lower limit level (a lower limit level higher than the suction port of discharge line 5), the flow control valve V2 closes, and the discharge stops. This prevents the liquid from flowing back from the gas suction section 32 of ejector 3 to buffer tank 4 and discharge line 5 due to the suction pressure of pump 2. [Explanation of symbols]

[0039] 1...Gas-dissolved liquid generation device 2…Pump 3... Ejector, 31... Inlet, 32... Gas suction, 33... Discharge 4…Buffer Tank 5… Discharge line 6... Tank 7…Primary suction line 8…Return Line 9...Inflow line 10...Gas suction line 11…Gas introduction line 12… Liquid level sensor V1, V2… Flow control valves

Claims

1. A pump for sucking up liquid, An ejector is positioned on the primary side of this pump and injects gas into the flow of the liquid introduced by the suction to discharge the gas-dissolved liquid, A buffer tank capable of storing the gas introduced by suction or the liquid that flows back from the gas suction section of the ejector, A discharge line that discharges the liquid from this buffer tank to the primary suction line of the pump, Equipped with, The buffer tank is positioned directly above the horizontally positioned gas suction section. A gas suction line, which is upright and in communication with the gas suction section, is drawn into the buffer tank from the bottom of the buffer tank. The discharge line is connected to the side portion near the bottom of the buffer tank. A gas-dissolved liquid generation device characterized by the following.

2. A pump for sucking up liquid, An ejector is positioned on the primary side of this pump and injects gas into the flow of the liquid introduced by the suction to discharge the gas-dissolved liquid, A buffer tank capable of storing the gas introduced by suction or the liquid that flows back from the gas suction section of the ejector, A discharge line that discharges the liquid from this buffer tank to the primary suction line of the pump, Equipped with, The discharge line includes a valve that discharges the liquid based on the liquid level of the liquid in the buffer tank. The valve starts discharge when the liquid level reaches an upper limit liquid level lower than the gas suction port in the buffer tank, and stops discharge when the liquid level reaches a lower limit liquid level higher than the suction port of the discharge line in the buffer tank. A gas-dissolved liquid generation device characterized by the following.

3. The discharge line includes a valve that discharges the liquid based on the liquid level of the liquid in the buffer tank. The gas-dissolved liquid generating apparatus according to claim 1, characterized in that the valve starts discharge when the liquid level reaches an upper limit liquid level lower than the gas suction port in the buffer tank, and stops discharge when the liquid level reaches a lower limit liquid level higher than the suction port of the discharge line in the buffer tank.

4. A pump for sucking up liquid, An ejector is positioned on the primary side of this pump and injects gas into the flow of the liquid introduced by the suction to discharge the gas-dissolved liquid, A buffer tank capable of storing the gas introduced by suction or the liquid that flows back from the gas suction section of the ejector, A discharge line that discharges the liquid from this buffer tank to the primary suction line of the pump, Equipped with, The ejector is housed in the buffer tank. A gas-dissolved liquid generation device characterized by the following.

5. The discharge line includes a valve that discharges the liquid based on the liquid level of the liquid in the buffer tank. The gas-dissolved liquid generating apparatus according to claim 4, characterized in that the valve starts discharge when the liquid level reaches an upper limit liquid level lower than the gas suction section, and stops discharge when the liquid level reaches a lower limit liquid level higher than the suction port of the discharge line in the buffer tank.

6. A method for producing a gas-dissolved liquid using a gas-dissolved liquid production apparatus according to any one of claims 1, 2, or 4, The process by which the liquid that has flowed back from the gas suction section is stored in the buffer tank, The process by which the liquid is discharged from the buffer tank to the primary suction line of the pump on the discharge side of the ejector, A method for producing a gaseous dissolved liquid, characterized by having the following:

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