Fine bubble-containing liquid manufacturing device, fine bubble-containing liquid concentration device, and method for manufacturing fine bubble-containing liquid

Abstract

To provide a fine bubble-containing liquid manufacturing device that can efficiently and stably generate fine bubble-containing liquid having high concentration, and to provide a fine bubble-containing liquid concentration device and a method for manufacturing fine bubble-containing liquid.SOLUTION: A fine bubble-containing liquid manufacturing device includes: a pump 708 installed downstream of a liquid recovery part 1500 and compressing liquid W1 that does not include UFB; and a pump 709 for compressing UFB-containing liquid W2, where the pump 708 has a flow rate that is two or more times and six or less times larger than a flow rate of the pump 709 that compresses the UFB-containing liquid W2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a fine bubble-containing liquid manufacturing apparatus, a fine bubble-containing liquid concentrating apparatus, and a fine bubble-containing liquid manufacturing method. [Background technology]

[0002] In recent years, technologies that utilize the properties of minute bubbles (fine bubbles) have been developed. Fine bubbles are distinguished into microbubbles, which are 1 to 100 μm in diameter, and ultrafine bubbles (UFB), which are less than 1.0 μm in diameter.

[0003] Patent Document 1 discloses a method for generating UFBs with a diameter of less than 1.0 μm by driving a heating resistor element to generate film boiling in a liquid. Patent Document 1 also discloses an apparatus for efficiently generating a highly concentrated UFB-containing liquid by circulating the generated UFB-containing liquid through a filter disposed in a circulation path. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-126603 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the method described in Patent Document 1, the pressure in the circulation path was not sufficiently optimized, and the generated UFB was sometimes destroyed when passing through the filter, which raised the risk of not being able to efficiently generate a high-concentration fine bubble-containing liquid over a long period of circulation.

[0006] Therefore, the present invention provides a fine bubble-containing liquid manufacturing apparatus, a fine bubble-containing liquid concentrating apparatus, and a fine bubble-containing liquid manufacturing method that can efficiently and stably produce high-concentration fine bubble-containing liquid. [Means for solving the problem]

[0007] Therefore, the fine bubble-containing liquid manufacturing apparatus of the present invention comprises a storage unit for storing a liquid, a generating means for generating fine bubbles in the liquid supplied from the storage unit, a storage unit for storing the fine bubble-containing liquid containing the fine bubbles generated by the generating means, a filter means for separating the liquid supplied from the storage unit into a fine bubble-containing liquid containing predetermined fine bubbles that cannot pass through micropores and a liquid that does not contain the predetermined fine bubbles, and a circulation means for circulating the liquid among the storage unit, the generating means, the storage unit and the filter means, wherein the circulation means includes a first pump for sending the fine bubble-containing liquid containing the predetermined fine bubbles from the filter means to the storage unit, and a second pump for sending the liquid that does not contain the predetermined fine bubbles from the filter means to the storage unit, and the flow rate of the first pump is at least two times but not more than six times the flow rate of the second pump. [Effects of the Invention]

[0008] The present invention provides a fine bubble-containing liquid manufacturing apparatus, a fine bubble-containing liquid concentrating apparatus, and a fine bubble-containing liquid manufacturing method that can efficiently and stably produce a high-concentration fine bubble-containing liquid. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing a UFB-containing liquid manufacturing apparatus. [Figure 2] FIG. 2 is a perspective view showing a UFB generating unit. [Figure 3] FIG. 2 is an exploded perspective view of the heating element substrate. [Figure 4]5 is a schematic diagram showing an example of the internal structure of a liquid recovery unit. FIG. [Figure 5] FIG. 2 is a block diagram showing a control configuration in the UFB-containing liquid manufacturing apparatus. [Figure 6] 10 is a flowchart showing a process for producing a UFB-containing liquid. [Figure 7] 10 is a flowchart showing a UFB generation process. [Figure 8] FIG. 1 is a schematic diagram showing a UFB-containing liquid manufacturing apparatus. [Figure 9] 10 is a flowchart showing a UFB generation process. [Figure 10] FIG. 1 is a schematic diagram showing a UFB-containing liquid manufacturing apparatus equipped with a three-way valve. [Figure 11] FIG. 1 is a schematic diagram showing a UFB-containing liquid concentrating device. DETAILED DESCRIPTION OF THE INVENTION

[0010] A first embodiment of the present invention will be described below with reference to the drawings. In this embodiment, as an example of a fine bubble-producing apparatus, a UFB-containing liquid producing apparatus that efficiently produces ultrafine bubbles with a diameter of less than 1.0 μm will be described.

[0011] 1 is a schematic diagram showing a UFB-containing liquid manufacturing apparatus 2000 to which this embodiment can be applied. The UFB-containing liquid manufacturing apparatus 2000 includes a liquid supply unit 600, a gas supply unit 800, a supply liquid storage chamber 900, a UFB-containing liquid storage chamber 970, a liquid recovery unit 1500, and a UFB generation unit 1000.

[0012] The liquid supply unit 600 includes a liquid storage unit 601, two pumps 602 and 603, and a degassing unit 604. The liquid W1 stored in the liquid storage unit 601 is sent by the pump 602 via the degassing unit 604 to a supply liquid storage chamber (storage unit) 900 that can store liquid. A membrane that allows only gas to pass through is provided inside the degassing unit 604. By reducing the pressure inside the degassing unit 604 by the action of the pump 603, only the gas passes through the membrane, separating the gas and the liquid, and the liquid W1 flows toward the supply liquid storage chamber 900, while the gas is discharged to the outside. The liquid stored in the liquid storage unit 601 may contain various gases dissolved therein. However, by removing the dissolved gases using the degassing unit 604 before sending the liquid to the supply liquid storage chamber 900, the dissolution efficiency of the gas G, which will be described later, is increased.

[0013] The gas supply unit 800 has a cylinder (gas storage unit) 804 for storing a desired gas G, a valve 806, and an adjustment valve 807, and the gas G is supplied to the supply liquid storage chamber 900 with its flow rate adjusted. The gas G can be selected arbitrarily from oxygen, hydrogen, nitrogen, carbon dioxide, argon, propane, and the like.

[0014] The supply liquid storage chamber 900 stores liquid W1, which is liquid W1 supplied from the liquid supply unit 600 and in which a desired gas G is dissolved. A temperature sensor 905 detects the temperature of the liquid stored in the supply liquid storage chamber 900. A liquid level sensor 902 is disposed at a predetermined height in the supply liquid storage chamber 900 and detects the liquid level of the liquid W1. A solubility sensor 907 detects the solubility of the gas G in the liquid W1 stored in the supply liquid storage chamber 900. Although not shown in the figure, a stirring means may be provided inside the supply liquid storage chamber 900 to uniformly distribute the temperature and UFB of the liquid W1.

[0015] The cooling unit 903 can control the temperature of the liquid W1 contained in the supply liquid storage chamber 900 and cools the liquid W1 when it becomes hot. To efficiently dissolve the desired gas G, it is preferable that the temperature of the liquid W1 be as low as possible. In this embodiment, the temperature of the liquid W1 is detected by the temperature sensor 905, and the cooling unit 903 is used to adjust the temperature of the liquid W1 to 10°C or less. The configuration of the cooling unit 903 is not particularly limited, but it is possible to adopt, for example, a system using a Peltier element or a system that circulates liquid cooled by a chiller. In the latter case, a cooling pipe for circulating the cooling liquid may be wrapped around the outer periphery of the supply liquid storage chamber 900 as shown in FIG. 1, or the supply liquid storage chamber 900 may have a hollow structure and the cooling pipe may be disposed within the hollow. Alternatively, the cooling pipe may be immersed in the liquid W1 in the supply liquid storage chamber 900.

[0016] The UFB generation unit 1000 generates UFB in the liquid W1 supplied from the supply liquid storage chamber 900. In this embodiment, a Thermal-Ultra Fine Bubble (hereinafter also referred to as "T-UFB") method is used, which generates film boiling at the interface between a heating element and the liquid.

[0017] FIG. 2 is a perspective view showing the UFB generation unit 1000, and FIG. 3 is an exploded perspective view of the heating element substrate 1100. The UFB generation unit 1000 includes multiple heating element substrates 1100. The heating element substrate 1100 includes a Si substrate 1101 and an outlet plate 1110 (see FIG. 3). The outlet plate 1110 has multiple outlets 1112 arranged therein, and multiple heating elements 1102 arranged on the Si substrate 1101. The multiple heating element substrates 1100 are supported and arranged on a support member 1300 attached to the UFB generation unit housing 1400. Terminals 1103 for connection to flexible wiring 1200 are arranged on the Si substrate 1101.

[0018] Power is supplied to the heating elements 1102 via flexible wiring 1200 and terminals 1103, and the heating elements 1102 generate heat when a voltage pulse is applied. Liquid is supplied to the heating elements 1102 from a supply port 1104. When the liquid is supplied to the heating elements 1102 and the heating elements 1102 generate heat, droplets containing UFB are ejected from ejection ports 1112. In addition, a temperature sensor (temperature detection means) 1107 is formed in an area of ​​the heating element substrate 1100 where the heating elements 1102 are not arranged, and reads the temperature of the heating element substrate 1100.

[0019] The droplets ejected from the ejection port 1112 are collected by the collection unit 1002 (see FIG. 1).

[0020] Returning to the explanation of FIG. 1 , the UFB-containing liquid storage chamber 970 stores the UFB-containing liquid W2 delivered by the pump 707. The UFB-containing liquid storage chamber 970 is equipped with a cooling unit 973, and the UFB-containing liquid W2 in the UFB-containing liquid storage chamber 970 is maintained at a constant temperature. A UFB concentration sensor 976 detects the UFB concentration of the liquid W2 stored in the UFB-containing liquid storage chamber 970. A valve 974 is opened when the liquid W2 stored in the UFB-containing liquid storage chamber 970 is discharged to an external container via a recovery path 979. Liquid level sensors 972, 977, and 978 detect the liquid level inside the UFB-containing liquid storage chamber 970. Details of liquid level detection will be described later.

[0021] The liquid recovery unit 1500 has a function of filtering UFBs from the UFB-containing liquid W2 delivered from the UFB-containing liquid storage chamber 970 and discharging liquid W1 that does not contain UFBs of a predetermined size or larger, and for example, a cross-flow filter is used. As the UFB-containing liquid W2 passes through the liquid recovery unit 1500, a portion of the UFB-containing liquid W2 is discharged as filtrate (liquid W1 that does not contain UFBs of a predetermined size or larger) by the suction force of the pump 708 and sent to the supply liquid storage chamber 900. The remaining UFB-containing liquid W2 is returned to the UFB-containing liquid storage chamber 970 by the pump 709. Details of the liquid recovery unit 1500 will be described later.

[0022] 1, the supply liquid storage chamber 900, UFB generation unit 1000, UFB-containing liquid storage chamber 970, and liquid recovery unit 1500 are connected by piping. Pumps 707 and 708 form a circulation path A through which the liquid circulates through UFB generation unit 1000. During UFB generation, circulation through circulation path A is performed at a flow rate that matches the total amount of droplets discharged from discharge port 1112 of UFB generation unit 1000 (see FIGS. 2 and 3), thereby maintaining stable discharge and enabling efficient UFB generation.

[0023] The location and number of pumps are not limited to those shown in FIG. 1 . Furthermore, pumps and valves necessary for driving each component may be installed within the configuration. However, it is preferable to use pumps with minimal pulsation and flow rate variation to avoid impairing the UFB production efficiency. Furthermore, the recovery path 979 and valve 974 for recovering the UFB-containing solution W2 may be installed at other locations on the liquid circulation path, rather than in the UFB-containing solution storage chamber 900. Components that come into contact with the UFB-containing solution, such as the piping 700, pump 707, supply solution storage chamber 900, and UFB production unit 1000, are preferably made of highly corrosion-resistant materials. For example, fluororesins such as polytetrafluoroethylene (PTFE) and perfluoroalkoxyalkane (PFA), metals such as SUS316L, and other inorganic materials are suitable. This allows for efficient UFB production even when highly corrosive gas G or liquid W1 is used.

[0024] FIG. 4 is a schematic diagram showing an example of the internal structure of the liquid recovery unit 1500. The liquid recovery unit 1500 can filter UFB350 from the UFB-containing liquid W2. In the liquid recovery unit 1500, the supply liquid (UFB-containing liquid W2) passes through the filter membrane (micropore flow path unit) 320 in the supply direction (rightward in the figure) with positive pressure relative to the permeation side. Liquid W1 that does not contain UFB350 or that contains UFB (second fine bubbles) that are finer than the desired size of UFB350 (first fine bubbles) can pass through the micropores of the filter membrane 320 in the vertical direction in the figure. In other words, the filter membrane 320 can separate UFB350 of a desired size or larger from the UFB-containing liquid W2.

[0025] A plurality of hollow fibers 1501 with micropores are arranged in the liquid recovery section 1500. As the UFB-containing liquid W2 passes through the interior of the hollow fibers 1501, a portion of the liquid passes through the micropores of the filter membrane 320 of the hollow fibers 1501 as a filtrate (liquid W1 that does not contain UFBs 350 with a particle size equal to or larger than the desired size) due to the pressure of the pump 708. The filtrate (liquid W1) that passed through the micropores of the filter membrane 320 is sent to the supply liquid storage chamber 900 via piping (see FIG. 1). The UFB-containing liquid W2 that did not pass through the micropores of the filter membrane 320 is sent to the UFB-containing liquid storage chamber 970 via piping. In FIG. 1, the path that runs from the UFB-containing liquid storage chamber 970 through the liquid recovery section 1500 and back to the UFB-containing liquid storage chamber 970 is shown as circulation path B.

[0026] 5 is a block diagram showing the control configuration of a UFB-containing liquid manufacturing apparatus 2000 according to this embodiment. A CPU 2001 controls the entire apparatus using a RAM 2003 as a work area in accordance with a program stored in a ROM 2002. A pump control unit 2004, under the direction of the CPU 2001, controls the operation of various pumps, including pumps 602, 603, 707, 708, and 709, included in the circulation path shown in FIG. 1 . A valve control unit 2005, under the direction of the CPU 2001, is configured to be able to control the opening and closing of various valves, including valves 806 and 904. A sensor control unit 2006, under the direction of the CPU 2001, controls various sensors, including a solubility sensor 907, liquid level sensors 902, 972, 977, and 978, a temperature sensor 905, and a UFB concentration sensor 976, and provides the CPU 2001 with the detected values ​​of the various sensors. The cooler control unit 2007 controls the coolers 903 and 973 under the instruction of the CPU 2001. The UFB generation unit 1000 generates UFB under the instruction of the CPU 2001.

[0027] FIG. 6 is a flowchart showing the process for producing a UFB-containing liquid in the UFB-containing liquid producing apparatus 2000 of this embodiment. The process for producing a UFB-containing liquid in this embodiment will be described below with reference to the flowchart in FIG. 6. The series of processes shown in FIG. 6 are performed by the CPU 2001 of the UFB-containing liquid producing apparatus 2000 loading program code stored in the ROM 2002 into the RAM 2003 and executing it. Alternatively, some or all of the functions of the steps in FIG. 6 may be realized by hardware such as an ASIC or electronic circuit. The symbol "S" in the description of each process indicates a step in the flowchart.

[0028] When the process of generating a UFB-containing liquid is started, the CPU 2001 stores a predetermined amount of liquid in the supply liquid storage chamber 900 in S601. Specifically, the CPU 2001 drives the pumps 602 and 603 while monitoring the detection of the liquid level sensor 902. As a result, the liquid W1 stored in the liquid supply unit 600 is sent to the supply liquid storage chamber 900 while being degassed in the degassing unit 604. When the liquid level sensor 902 detects the liquid level, the CPU 2001 stops driving the pumps 602 and 603. As a result, a predetermined amount of liquid W1 is stored in the supply liquid storage chamber 900. In S602, the CPU 2001 starts temperature control of the liquid W1 stored in the supply liquid storage chamber 900. Specifically, the CPU 2001 drives the cooling unit 903 while monitoring the temperature detected by the temperature sensor 905. When the temperature detected by the temperature sensor 905 drops below 10° C., the CPU 2001 opens the valve 806 in step S603 to start dissolving the gas.

[0029] When solubility sensor 907 detects a predetermined solubility, CPU 2001 drives UFB generation unit 1000 in S604 to generate UFB. At this time, pumps 708 and 709 are driven along with pump 707 to circulate the liquid through circulation paths A and B. Then, when UFB concentration sensor 976 detects a predetermined concentration, the driving of UFB unit 1000 is stopped.

[0030] Temperature control and gas solubility control are continuously performed during UFB generation. That is, while monitoring temperature sensor 905 and solubility sensor 907, the operation of each component is started and stopped to keep the temperature and gas solubility within the predetermined ranges. Then, in S605, CPU 2001 stops the operation of all components, including the pump, UFB generation unit 1000, and cooling unit 903, and opens valve 974 to recover the UFB-containing liquid, thereby completing the process.

[0031] Next, the details of the process for efficiently producing a highly concentrated UFB-containing solution in the UFB production step (S604) will be described.

[0032] Fig. 7 is a flowchart showing the UFB generation process in S604 of Fig. 6. The process for generating a UFB-containing solution in this embodiment will be described below using the flowchart in Fig. 7. Note that the symbol "S" in the description of each process indicates a step in the flowchart.

[0033] When the UFB generation process is started, the CPU 2001 drives the pump 707 to send liquid W1 to the UFB generation unit 1000 in S701, and drives the UFB generation unit 1000 in S702. When the UFB-containing liquid generated in the UFB generation unit 1000 is sent to the UFB-containing liquid storage chamber 970 by the pump 707, the amount of UFB-containing liquid stored inside the UFB-containing liquid storage chamber 970 gradually increases. In S703, when the liquid level sensor 978 detects the liquid level (based on the detection result), the CPU 2001 proceeds to S704 and starts driving the pumps 708 and 709 under the first condition. This causes the UFB-containing liquid W2 to pass through the liquid recovery unit 1500. At this time, the set flow rate of the pump 708 is set to the same as the set flow rate of the pump 707.

[0034] As described above, in the liquid recovery section 1500, a portion of the liquid W1 from the UFB-containing liquid W2 passes through the hollow fibers 1501 by the pressure of the pump 708 and is sent to the supply liquid storage chamber 900. The remaining UFB-containing liquid W2 is returned to the UFB-containing liquid storage chamber 970 by the pump 709. Note that, by sending a portion of the liquid W1 to the supply liquid storage chamber 900, the UFB-containing liquid W2 returned to the UFB-containing liquid storage chamber 970 has a higher UFB concentration (number of UFBs per volume) than before passing through the liquid recovery section 1500. Furthermore, during this time, the UFB-containing liquid W2 is also sent from the UFB generation unit 1000 to the UFB-containing liquid storage chamber 970. Therefore, by repeating the above process, the UFB-containing liquid W2 stored in the UFB-containing liquid storage chamber 970 gradually becomes more concentrated while ideally maintaining a constant liquid volume.

[0035] However, due to individual differences in the pumps and changes over time, the flow rates of the pumps 707 and 708 are not always constant, and the amount of liquid in the UFB-containing liquid storage chamber 970 may increase or decrease over long periods of operation due to pump balance differences. Therefore, in S705, the CPU 2001 determines whether the liquid level sensor 977 has detected a liquid level. If a liquid level is detected, the process proceeds to S706, where the pumps 708 and 709 are stopped. This causes only the pump 707 to operate, and the amount of liquid in the UFB-containing liquid storage chamber 970 gradually increases. Thereafter, if the liquid level sensor 978 detects a liquid level in S707, the CPU 2001 proceeds to S708, where the pumps 708 and 709 are operated under the first condition, and then proceeds to S709. If it is determined in S705 that the liquid level sensor 977 has not detected a liquid level, the process proceeds directly to S709.

[0036] In S709, the CPU 2001 determines whether the liquid level sensor 972 has detected the liquid level. If the liquid level sensor 972 has detected the liquid level, the process proceeds to S710, where the pumps 708 and 709 are switched to a second condition with a higher liquid delivery rate than the first condition. This gradually reduces the amount of liquid in the UFB-containing liquid storage chamber 970. Thereafter, in S711, if the liquid level sensor 978 detects the liquid level, the CPU 2001 proceeds to S712, where the pumps 708 and 709 are returned to the first condition, and then proceeds to S713. On the other hand, if the liquid level sensor 972 does not detect the liquid level in S709, the process proceeds to S713.

[0037] In S713, the CPU 2001 determines whether the UFB concentration in the UFB-containing liquid storage chamber 970 has reached a predetermined concentration based on the detection value of the UFB concentration sensor 976. If the predetermined concentration has not been reached, the process returns to S705 and is repeated. If the UFB has reached the predetermined concentration, the process ends.

[0038] In this embodiment, the flow rate ratio of pump 708 to pump 709 is set to a range of 1:2 to 1:6. That is, the flow rate of pump 709 is set to be at least two times but not more than six times the flow rate of pump 708. Both the first and second conditions are satisfied, with the flow rate of pump 709 being at least two times but not more than six times the flow rate of pump 708. By setting the flow rate of pump 709 higher than the flow rate of pump 708 in this manner, UFB of a desired size are less likely to pass through hollow fibers 1501 or be lost, and liquid W1 can pass through hollow fibers 1501 while filtering the UFB. In this embodiment, the first conditions for pumps 708 and 709 are set to 30 mL / min and 120 mL / min, respectively, and the second conditions are set to 40 mL / min and 160 mL / min.

[0039] When a crossflow filter is used as the liquid recovery unit 1500, consider the change in UFB diameter when the UFB-containing liquid W2 passes through the micropores in the internal hollow fiber membrane. When the UFB-containing liquid W2 passes through the micropores, it passes through a relatively narrow flow path, causing a pressure loss and reducing the fluid pressure. Therefore, it is thought that the UFB diameter in the flow path immediately after passing through the micropores will increase.

[0040] According to the study by the present inventors, leakage of UFB with a diameter of 80 nm or more was confirmed when a crossflow filter with a pore size of 500 nm was used in the liquid recovery unit 1500. Here, we will look at the ratio between the pore size of the crossflow filter and the diameter of the UFB.

[0041] Crossflow filter pore size: UFB diameter = 500:80 500:80=6.25:1≒6:1 From this, it can be said that if the pore diameter of the cross-flow filter is larger than six times the desired UFB diameter, UFB of the desired diameter will leak out even when UFB expansion is taken into account. Therefore, it is desirable that the cross-flow filter pore diameter be six times or less the desired UFB diameter. Note that in the above, a liquid containing UFB with a diameter of 80 nm or more was used as the target for concentration, but it goes without saying that the appropriate cross-flow filter pore diameter will change depending on the size of the bubbles to be concentrated. Furthermore, in this embodiment, the cross-flow filter pore diameter is set to 50 nm to 200 nm.

[0042] In this specification, UFB is generated using the T-UFB method, which utilizes film boiling caused by sudden heat generation, but the method of generating UFB is not limited to this. UFB can also be generated using the Venturi method, piezo, etc.

[0043] In this way, pump 708, which applies pressure to UFB-free liquid W1, and pump 709, which applies pressure to UFB-containing liquid W2, are provided downstream of liquid recovery section 1500, and the flow rate of pump 709 is set to be at least two times but not more than six times the flow rate of pump 708. This makes it possible to provide a fine bubble-containing liquid manufacturing apparatus, a fine bubble concentrated liquid manufacturing apparatus, and a fine bubble-containing liquid manufacturing method that can efficiently and stably produce a high-concentration fine bubble-containing liquid.

[0044] (Second embodiment) A second embodiment of the present invention will be described below with reference to the drawings. The basic configuration of this embodiment is the same as that of the first embodiment, so only the characteristic configuration will be described below. This embodiment describes a method for performing a sequence (collectively referred to as a recovery sequence) to cool the UFB production unit 1000 and remove bubbles from the UFB production unit 1000 when the UFB manufacturing apparatus is operated for a long period of time.

[0045] FIG. 8 is a schematic diagram showing a UFB-containing liquid manufacturing apparatus 2000 to which this embodiment can be applied. The UFB-containing liquid manufacturing apparatus 2000 of this embodiment includes three-way valves 711 and 712. In the figure, the white portions of the three-way valves 711 and 712 indicate where the valves are open, and the black portions indicate where the valves are closed. That is, in FIG. 8, the liquid flow is the same as in FIG. 1, and UFB production is performed in the same manner as in the first embodiment. The configuration other than the three-way valves 711 and 712 is the same as in the first embodiment.

[0046] 9 is a flowchart showing the UFB production process shown in S604 of FIG. 6 in this embodiment. FIG. 10 is a schematic diagram showing the configuration of the UFB-containing liquid production apparatus 2000 when the three-way valves 711 and 712 are switched from the state of the three-way valves 711 and 712 in the UFB-containing liquid production apparatus 2000 shown in FIG. 8. The UFB-containing liquid production process in this embodiment will be described below using the flowchart of FIG. 9. Note that the symbol "S" in the description of each process indicates a step in the flowchart. Note that the processes from S901 to S912 in FIG. 9 are similar to the processes from S701 to S712 in FIG. 7, and therefore will not be described here.

[0047] In S913, the CPU 2001 determines whether a predetermined time has elapsed since the UFB generation unit 1000 was driven in S902. If the predetermined time has not elapsed, the process proceeds to S915, where the CPU 2001 determines whether the UFB concentration in the UFB-containing liquid storage chamber 970 has reached a predetermined concentration based on the detection value of the UFB concentration sensor 976. If the CPU 2001 determines in S915 that the predetermined concentration has not been reached, the process returns to S905 and repeats the process. If the CPU 2001 determines in S915 that the UFB has reached the predetermined concentration, the process ends.

[0048] If it is determined in S913 that the predetermined time has elapsed, the CPU 2001 proceeds to S914 and executes a recovery sequence. In the recovery sequence, the three-way valves 711 and 712 are switched to the orientation shown in FIG. 10 . As a result, a circulation path C is formed that circulates the liquid between the UFB-containing liquid storage chamber 900 and the UFB generation unit 1000 without passing through the UFB-containing liquid storage chamber 970. The recovery sequence, for example, cools the UFB generation unit 1000 by increasing the flow rate of the pump 707 compared to when it is running while the heating element of the UFB generation unit 1000 is stopped. Alternatively, air bubbles accumulated inside the path and the UFB generation unit 1000 may be removed by driving the pump 707 while keeping the valve 710 closed for a certain period of time and then opening the valve 710. After the recovery sequence is completed, the CPU 2001 returns the three-way valves 711 and 712 to the orientation shown in FIG. 8 .

[0049] According to this embodiment, when the recovery sequence is performed, the liquid can be circulated without passing through the UFB-containing liquid storage chamber 970. Therefore, the liquid can be flowed under pump flow rate conditions that are optimal for the recovery sequence without affecting the UFBs generated in the UFB-containing liquid storage chamber 970. This allows for stable, continuous operation over long periods of time.

[0050] (Third embodiment) A third embodiment of the present invention will be described below with reference to the drawings.

[0051] 11 is a schematic diagram showing an apparatus for concentrating ultra-fine bubble-containing liquid (hereinafter also referred to as an UFB-containing liquid concentrator) 3000 according to this embodiment. The apparatus for concentrating UFB-containing liquid 3000 according to this embodiment does not include a UFB generation unit, but is used to concentrate a UFB-containing liquid W2 generated in a separate process. Therefore, the UFB-containing liquid W2 generated in advance is supplied to a UFB-containing liquid storage chamber 970. The UFB-containing liquid W2 is then circulated between the UFB-containing liquid storage chamber 970 and a liquid recovery unit 1500. During this process, the liquid W1 that does not contain UFBs of a desired size or larger is recovered in a separation container 980, allowing the UFB concentration in the UFB-containing liquid W2 to be gradually increased.

[0052] In the above circulation, the three-way valve 971 is set to return the UFB-containing liquid W2 from the liquid recovery unit 1500 to the UFB-containing liquid storage chamber 970. Then, by driving the pumps 708 and 709 under the same conditions as in the above embodiment, the liquid can be suitably circulated between the liquid recovery unit 1500 and the UFB-containing liquid storage chamber 970. In this embodiment, the liquid recovery unit 1500 also filters out UFBs from the UFB-containing liquid. Here, the flow rate of the pump 709 is set to be between two and six times the flow rate of the pump 708. The liquid delivered to the separation container 980 via the pump 708 does not contain UFBs with diameters equal to or larger than a desired size. Furthermore, the UFB-containing liquid W2 circulated between the UFB-containing liquid storage chamber 970 and the liquid recovery unit 1500 via the pump 709 has an increased UFB concentration as it circulates. When the UFB concentration sensor 976 detects that the UFB concentration in the UFB-containing liquid chamber 970 has reached a predetermined concentration, the valve 971 is switched to discharge the liquid stored in the UFB-containing liquid chamber 970 into the external container 975 .

[0053] (Other embodiments) Although the above explanation has been given using UFB as an example, the present disclosure can be applied to fine bubbles in general. However, in the case of UFB, buoyancy is less likely to act and the bubbles rarely rise to the liquid surface and disappear, making it possible to more effectively utilize the concentrated liquid manufacturing device of the present invention.

[0054] The disclosure of this embodiment includes the following configurations and methods.

[0055] (Configuration 1) a storage section for storing a liquid; a generating means for generating fine bubbles in the liquid supplied from the storage section; a storage section for storing a fine bubble-containing liquid containing the fine bubbles generated by the generating means; a filter means capable of separating the liquid supplied from the reservoir into a fine bubble-containing liquid containing predetermined fine bubbles that cannot pass through the micropores and a liquid not containing the predetermined fine bubbles; a circulation means for circulating a liquid among the storage unit, the generation means, the storage unit, and the filter means, The circulation means includes a first pump that sends a fine bubble-containing liquid containing the predetermined fine bubbles from the filter means to the storage section, and a second pump that sends a liquid that does not contain the predetermined fine bubbles from the filter means to the storage section, The apparatus for producing fine bubble-containing liquid is characterized in that the flow rate of the first pump is at least two times and at most six times the flow rate of the second pump.

[0056] (Configuration 2) 2. The fine bubble-containing liquid producing apparatus according to claim 1, wherein the filter means is a cross-flow filter having a hollow fiber membrane, and the fine pores are provided in the membrane of the hollow fiber.

[0057] (Configuration 3) 3. The fine bubble-containing liquid manufacturing apparatus according to claim 1, wherein the pore diameter of the micropores is larger than the diameter of the predetermined fine bubbles.

[0058] (Configuration 4) 4. The apparatus for producing a fine bubble-containing liquid according to configuration 3, wherein the pore diameter of the micropores is 50 nm to 200 nm.

[0059] (Configuration 5) The fine bubble-containing liquid manufacturing apparatus according to any one of configurations 1 to 4, wherein the circulation means further includes a third pump that sends the fine bubble-containing liquid containing the fine bubbles generated by the generation means from the generation means to the storage section.

[0060] (Configuration 6) Further provided is a liquid level detection means for detecting the height of the liquid level stored in the storage section, The fine bubble-containing liquid manufacturing apparatus according to configuration 5, wherein when the liquid level detection means detects a liquid level lower than the first height, the circulation means drives the third pump while stopping the first pump and the second pump.

[0061] (Configuration 7) When the liquid level detection means detects a liquid level that is higher than the first height and lower than the second height, the circulation means drives the first pump and the second pump under a first condition; The fine bubble-containing liquid manufacturing apparatus according to configuration 6, wherein when the liquid level detection means detects a liquid level higher than the second height, the circulation means drives the first pump and the second pump under second conditions in which the liquid delivery flow rate is higher than that under the first conditions.

[0062] (Configuration 8) The fine bubble-containing liquid manufacturing device according to any one of configurations 1 to 7, wherein the circulation means is capable of switching between a first circulation path that runs from the storage unit via the generation means and the storage unit and then returns to the storage unit, and a second circulation path that runs from the storage unit via the generation means and then returns to the storage unit without passing through the storage unit.

[0063] (Configuration 9) The fine bubble-containing liquid manufacturing apparatus according to configuration 8, wherein the circulation means switches from the first circulation path to the second circulation path when a predetermined time has elapsed since the start of operation of the generation means.

[0064] (Configuration 10) 10. The apparatus for producing a fine bubble-containing liquid according to any one of configurations 1 to 9, wherein the fine bubbles are ultrafine bubbles having a diameter of less than 1.0 μm.

[0065] (Configuration 11) a storage section for storing a fine bubble-containing liquid containing the generated fine bubbles; a filter means capable of separating a fine bubble-containing liquid containing predetermined fine bubbles that cannot pass through the micropores from a liquid not containing the predetermined fine bubbles; a supply means for supplying the fine bubble-containing liquid stored in the storage section to the filter means; A fine bubble-containing liquid concentrating device comprising: The supply means includes a first pump that sends a fine bubble-containing liquid containing the predetermined fine bubbles from the filter means to the storage section, and a second pump that sends a liquid that does not contain the predetermined fine bubbles from the filter means to the outside, The apparatus for concentrating fine bubble-containing liquid is characterized in that the flow rate of the first pump is not less than two times and not more than six times the flow rate of the second pump.

[0066] (Method 1) generating fine bubbles in the liquid supplied from the storage unit by a generating means; a step of storing a fine bubble-containing liquid containing the fine bubbles generated by the generating means in a storage section; a separation step of separating the liquid supplied from the reservoir into a fine bubble-containing liquid containing predetermined fine bubbles that cannot pass through the micropores of the filter means and a liquid not containing the predetermined fine bubbles; a control step of controlling the circulation of liquid between the container, the generating means, the storage unit, and the filtering means; A method for producing a fine bubble-containing liquid, comprising: In the control step, the flow rate of the fine bubble-containing liquid containing the predetermined fine bubbles sent from the filter means to the storage section is controlled to be at least two times and at most six times the flow rate of the liquid not containing the predetermined fine bubbles sent from the filter means to the storage section. [Explanation of symbols]

[0067] 970 UFB-containing liquid storage chamber 1000 UFB generating units 1500 Liquid recovery section 2000 UFB-containing liquid production equipment 2001 CPU 3000 UFB-containing liquid concentrator

Claims

1. a storage section for storing a liquid; a generating means for generating fine bubbles in the liquid supplied from the storage section; a storage section for storing a fine bubble-containing liquid containing the fine bubbles generated by the generating means; a filter means capable of separating the liquid supplied from the reservoir into a fine bubble-containing liquid containing predetermined fine bubbles that cannot pass through the micropores and a liquid not containing the predetermined fine bubbles; a circulation means for circulating a liquid among the storage unit, the generation means, the storage unit, and the filter means, The circulation means includes a first pump that sends a fine bubble-containing liquid containing the predetermined fine bubbles from the filter means to the storage section, and a second pump that sends a liquid that does not contain the predetermined fine bubbles from the filter means to the storage section, The apparatus for producing fine bubble-containing liquid, wherein the flow rate of the first pump is at least two times and at most six times the flow rate of the second pump.

2. 2. The fine bubble-containing liquid producing apparatus according to claim 1, wherein the filter means is a cross-flow filter having a hollow fiber membrane, and the micropores are provided in the membrane of the hollow fiber.

3. 2. The apparatus for producing fine bubble-containing liquid according to claim 1, wherein the pore diameter of the micropores is larger than the diameter of the predetermined fine bubbles.

4. 4. The apparatus for producing fine bubble-containing liquid according to claim 3, wherein the pore diameter of the micropores is 50 nm to 200 nm.

5. 2. The fine bubble-containing liquid manufacturing apparatus according to claim 1, wherein the circulation means further includes a third pump that sends the fine bubble-containing liquid containing the fine bubbles generated by the generation means from the generation means to the storage section.

6. Further provided is a liquid level detection means for detecting the height of the liquid level stored in the storage section, 6. The fine bubble-containing liquid manufacturing apparatus according to claim 5, wherein when the liquid level detection means detects a liquid level lower than a first height, the circulation means drives the third pump while stopping the first pump and the second pump.

7. When the liquid level detection means detects a liquid level that is higher than the first height and lower than the second height, the circulation means drives the first pump and the second pump under a first condition; 7. The fine bubble-containing liquid manufacturing apparatus according to claim 6, wherein when the liquid level detection means detects a liquid level higher than the second height, the circulation means drives the first pump and the second pump under second conditions in which the liquid delivery flow rate is higher than that under the first conditions.

8. 2. The fine bubble-containing liquid manufacturing apparatus according to claim 1, wherein the circulation means is capable of switching between a first circulation path that runs from the storage unit via the generating means and the storage unit and then returns to the storage unit, and a second circulation path that runs from the storage unit via the generating means and then returns to the storage unit without passing through the storage unit.

9. 9. The fine-bubble-containing liquid manufacturing apparatus according to claim 8, wherein the circulation means switches from the first circulation path to the second circulation path when a predetermined time has elapsed since the start of operation of the generation means.

10. 2. The apparatus for producing a fine bubble-containing liquid according to claim 1, wherein the fine bubbles are ultrafine bubbles having a diameter of less than 1.0 μm.

11. a storage section for storing a fine bubble-containing liquid containing the generated fine bubbles; a filter means capable of separating a fine bubble-containing liquid containing predetermined fine bubbles that cannot pass through the micropores from a liquid not containing the predetermined fine bubbles; a supply means for supplying the fine bubble-containing liquid stored in the storage section to the filter means; A fine bubble-containing liquid concentrating device comprising: The supply means includes a first pump that sends a fine bubble-containing liquid containing the predetermined fine bubbles from the filter means to the storage section, and a second pump that sends a liquid that does not contain the predetermined fine bubbles from the filter means to the outside, The apparatus for concentrating fine bubble-containing liquid, wherein the flow rate of the first pump is at least two times and at most six times the flow rate of the second pump.

12. generating fine bubbles in the liquid supplied from the storage unit by a generating means; a step of storing a fine bubble-containing liquid containing the fine bubbles generated by the generating means in a storage section; a separation step of separating the liquid supplied from the reservoir into a fine bubble-containing liquid containing predetermined fine bubbles that cannot pass through the micropores of the filter means and a liquid not containing the predetermined fine bubbles; a control step of controlling the circulation of liquid between the container, the generating means, the storage unit, and the filtering means; A method for producing a fine bubble-containing liquid, comprising: In the control step, the flow rate of the fine bubble-containing liquid containing the specified fine bubbles sent from the filter means to the storage section is controlled to be at least two times and at most six times the flow rate of the liquid not containing the specified fine bubbles sent from the filter means to the storage section.

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