Apparatus and method for producing ultrafine bubble-containing liquid

Abstract

To provide an apparatus and a method for producing an UFB-containing liquid which can suppress lowering of generation efficiency of UFB in long-term operation.SOLUTION: In an apparatus for producing an UFB-containing liquid, control means performs a first mode of circulating a liquid between an ultrafine bubble generation unit 1000 and a storage chamber 900 at a first flow rate, and a second mode of circulating the liquid at a second flow rate faster than the first flow rate, on the basis of a predetermined condition.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to an apparatus and method for producing a liquid containing ultra-fine bubbles. [Background technology]

[0002] In recent years, technologies have been developed that utilize the properties of minute bubbles, such as microbubbles with diameters of 1 to 100 μm and ultra-fine bubbles (hereinafter also referred to as "UFB") with diameters of less than 1.0 μm.

[0003] Patent Document 1 discloses an apparatus for generating fine bubbles at a high concentration by providing, in the same liquid circulation path, a pressure dissolving section that pressurizes and dissolves a desired gas in a liquid, and a fine bubble generating section that sprays the liquid from a fine nozzle to generate fine bubbles.

[0004] Furthermore, Patent Document 2 discloses a method for producing UFBs with diameters of less than 1.0 μm by generating film boiling in a liquid using a heating resistor element, and also discloses an apparatus for efficiently producing a liquid containing UFBs with a high number density by providing a circulation mechanism. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2015-181976 A [Patent Document 2] JP 2019-42732 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, when UFB manufacturing equipment is operated for a long time, the temperature of the UFB generation section rises, which can result in a decrease in the solubility of gas due to the rise in liquid temperature, which can reduce the amount of gas dissolved in the liquid and therefore the efficiency of UFB production.

[0007] Therefore, the present invention provides an apparatus and method for producing a UFB-containing liquid that can suppress a decrease in the UFB production efficiency during long-term operation. [Means for solving the problem]

[0008] Therefore, the apparatus for producing UFB-containing liquid of the present invention is an apparatus for producing ultra-fine bubble-containing liquid comprising: ultra-fine bubble generating means capable of generating ultra-fine bubbles in a liquid; circulation means for circulating the liquid in a circulation path including the ultra-fine bubble generating means; and control means for controlling the ultra-fine bubble generating means and the circulation means, wherein the control means switches between a first mode in which the liquid in the circulation path is circulated at a first flow velocity and a second mode in which the liquid is circulated at a second flow velocity faster than the first flow velocity, based on predetermined conditions. Effect of the Invention

[0009] According to the present invention, it is possible to provide an apparatus and method for producing a UFB-containing liquid that can suppress a decrease in the UFB production efficiency during long-term operation. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram showing an apparatus for producing liquid containing ultra-fine bubbles. [Diagram 2] FIG. 2 is a perspective view showing a UFB generating unit. [Diagram 3] FIG. 2 is an exploded perspective view of the heating element substrate. [Figure 4] FIG. 2 is a block diagram showing a control configuration in the UFB-containing liquid manufacturing apparatus. [Diagram 5] 1 is a flowchart showing a process for producing a UFB-containing liquid. [Figure 6] 13 is a flowchart showing a process of generating a UFB. [Figure 7]13 is a flowchart showing a process of generating a UFB. [Figure 8] FIG. 13 is a graph showing the temperature rise profile of the UFB generation unit. [Figure 9] 13 is a flowchart showing a process of generating a UFB. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] (First embodiment) A first embodiment of the present invention will now be described with reference to the drawings.

[0012] Fig. 1 is a schematic diagram showing an ultra-fine bubble-containing liquid manufacturing apparatus 2000 (hereinafter referred to as UFB-containing liquid manufacturing apparatus 2000) to which this embodiment can be applied. The UFB-containing liquid manufacturing apparatus 2000 includes a liquid supply section 600, a gas dissolving section 800, a storage chamber 900, and an ultra-fine bubble generating unit 1000 (hereinafter referred to as UFB generating unit 1000). In Fig. 1, solid arrows indicate the flow of liquid, and dashed arrows indicate the flow of gas.

[0013] The liquid supply unit 600 includes a liquid storage unit 601, two pumps 602 and 603, and a degassing unit 604. The liquid W stored in the liquid storage unit 601 is sent by the pump 602 to a storage chamber 900 capable of storing liquid via the degassing unit 604. A membrane through which only gas can pass is provided inside the degassing unit 604. By reducing the pressure inside the degassing unit 604 by the action of the pump 603, only gas passes through the membrane, and the gas and liquid are separated, and the liquid W is directed toward the storage chamber 900, and the gas is discharged to the outside. There is a possibility that various gases are dissolved in the liquid stored in the liquid storage unit 601, but by removing the dissolved gases by the degassing unit 604 before sending the liquid to the storage chamber 900, the dissolution efficiency in the subsequent gas dissolution process can be improved.

[0014] The gas dissolving section 800 includes a gas supplying section 804, a pre-treatment section 801, a junction section 802, and a gas-liquid separation chamber 803. The gas supplying section 804 may be a cylinder that stores the desired gas G, but may also be a device that can continuously generate the desired gas G. For example, when the desired gas G is oxygen, the gas supplying section 804 may be a device that takes in air, removes nitrogen, and continuously pumps in the gas from which the nitrogen has been removed.

[0015] Gas G supplied from gas supply unit 804 is subjected to treatment such as discharge by pretreatment unit 801, and then merges with liquid W flowing out from storage chamber 900 at junction 802. At this time, part of gas G dissolves in liquid W. The merged gas G and liquid W are separated again by gas-liquid separation chamber 803, and only gas G not dissolved in liquid W is discharged to the outside. The liquid W with gas G dissolved therein is then sent to UFB generation unit 1000 by pump 703.

[0016] The storage chamber 900 contains a mixture of the liquid W supplied from the liquid supply unit 600, the liquid W in which the desired gas G has been dissolved by the gas dissolving unit 800, and the UFB-containing liquid generated by the UFB generation unit 1000. The temperature sensor 905 detects the temperature of the liquid contained in the storage chamber 900. The liquid level sensor 902 is disposed at a predetermined height in the storage chamber 900 and detects the liquid level of the liquid W. The UFB concentration sensor (concentration detection means) 906 detects the UFB concentration of the liquid W contained in the storage chamber 900. The solubility sensor 907 detects the solubility of the gas in the liquid W contained in the storage chamber 900. The valve 904 is opened when the liquid W contained in the storage chamber 900 is discharged to an external container via the recovery path 909. Although not shown in the figure, a stirring means for uniformizing the temperature of the liquid W and the distribution of UFB may be provided inside the storage chamber 900.

[0017] The cooling unit 903 can control the temperature of the liquid W contained in the storage chamber 900, and can cool the liquid W that has become hot. In order to efficiently dissolve the desired gas G in the gas dissolving unit 800, it is preferable that the temperature of the liquid W supplied to the gas dissolving unit 800 is as low as possible. In this embodiment, the temperature of the liquid W supplied to the gas dissolving unit 800 is adjusted to 10° C. or less using the cooling unit 903 while detecting the temperature of the liquid W with the temperature sensor 905. The configuration of the cooling unit 903 is not particularly limited, but it is possible to adopt, for example, a method using a Peltier element or a method of circulating a 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 storage chamber 900 as shown in FIG. 1, or the storage chamber 900 may have a hollow structure and the cooling pipe may be arranged in the hollow. In addition, the cooling pipe may be immersed in the liquid W in the storage chamber 900.

[0018] A valve 1003 (blocking means) is provided upstream of the UFB generation unit 1000, and a pump 704 is provided downstream of the UFB generation unit 1000.

[0019] FIG. 2 is a perspective view showing the UFB generating unit 1000, and FIG. 3 is an exploded perspective view of the heating element substrate 1100. The above-mentioned UFB generating unit 1000 generates UFB in the liquid W that is introduced. In this embodiment, the Thermal-Ultra Fine Bubble (hereinafter also referred to as "T-UFB") method, which generates film boiling at the interface between the heating element 1102 and the liquid, is used as the UFB generating method. The UFB generating unit 1000 includes a plurality of heating element substrates 1100. The heating element substrate 1100 includes a Si substrate 1101 and an outlet plate 1110, and a plurality of outlets 1112 are arranged in the outlet plate 1110, and a plurality of heating elements 1102 are arranged on the Si substrate 1101. The plurality of heating element substrates 1100 are supported and arranged on a support member 1300 attached to the UFB generating unit housing 1400. Terminals 1103 for connection to flexible wiring 1200 are arranged on the Si substrate 1101. Power is supplied to the heating elements 1102 via the flexible wiring 1200 and the 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 path 1104, and droplets containing UFB are ejected from ejection ports 1112 by causing the heating elements 1102 to generate heat. 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.

[0020] As shown in Fig. 1, the liquid supply section 600, the gas dissolving section 800, the storage chamber 900, and the UFB production unit 1000 are connected by piping 700, and a path is formed through which the liquid W circulates by a pump 702, a supply pump 703, and a recovery pump 704. Fig. 1 shows a case in which a circulation path A for dissolving the gas and a circulation path B for producing the UFB-containing liquid are formed. In this case, the circulation paths A and B can each circulate under any desired conditions.

[0021] In circulation path B, liquid W can be circulated regardless of whether the UFB generation unit 1000 is driven. When the UFB generation unit 1000 is not driven, the liquid circulates from the supply path 1104, through the surface of the heating element 1102, and through the outlet 1112. When the UFB generation unit 1000 is driven, the liquid supplied from the supply path 1104 and discharged from the outlet 1112 by driving the heating element 1102 circulates. The flow rate in circulation path B may be determined according to the total amount of droplets discharged from the outlet 1112 of the UFB generation unit 1000, etc.

[0022] 1 shows a configuration in which a gas dissolving section 800 is provided in the middle of the circulation path to provide a circulation path A for dissolving the gas, but a configuration in which the gas G is directly supplied to the containing chamber 900 can also be used. This makes it possible to realize a more compact manufacturing device for a UFB-containing liquid.

[0023] The position and number of pumps are not limited to those shown in FIG. 1. Furthermore, pumps and valves required for driving each part may be provided in the configuration of each part. However, it is preferable to use a pump with small pulsation and flow rate variation as the pump so as not to impair the generation efficiency of UFB. Furthermore, the recovery path 909 and valve 904 for recovering the liquid W may be provided at other positions in the liquid circulation path, not in the storage chamber 900. Furthermore, the temperature sensor 905, the UFB concentration sensor 906, and the solubility sensor 907 do not necessarily have to be provided at the positions shown in FIG. 1. These sensors may be provided at other positions as long as they are within the circulation path. Furthermore, they may be provided at multiple positions in the circulation path, and an average value may be output.

[0024] It is preferable that components that come into contact with the UFB-containing liquid, such as the piping 700, pump 702, supply pump 703, recovery pump 704, valve 1003, storage chamber 900, and UFB generation unit 1000, are made of highly corrosion-resistant materials. For example, fluororesins such as polytetrafluoroethylene (PTFE) and perfluoroalkoxyalkane (PFA), metals such as SUS316L, and other inorganic materials can be suitably used. This makes it possible to suitably generate UFBs even when highly corrosive gas G or liquid W is used.

[0025] In this embodiment, the liquid W is circulated between the UFB generation unit 1000 and the storage chamber 900 via the circulation path B, but the UFB generation unit 1000 includes a process of ejecting droplets from an ejection port and recovering them with a recovery member 1002. Therefore, the circulation path includes a portion where the liquid W turns into droplets and flies through the gap.

[0026] 4 is a block diagram showing a control configuration of the UFB-containing liquid manufacturing apparatus 2000 of this embodiment. The CPU 2001 controls the entire apparatus according to a program stored in the ROM 2002, using the RAM 2003 as a work area. The pump control unit 2004 controls the operation of various pumps including the pumps 602, 603, 702, 703, and 704 included in the circulation path shown in FIG. 1 under the instruction of the CPU 2001. The valve control unit 2005 is configured to be able to control the opening and closing of various valves including the valves 904 and 1003 under the instruction of the CPU 2001. The sensor control unit 2005 controls various sensors including the solubility sensor 907, the liquid level sensor 902, the temperature sensor 905, and the UFB concentration sensor 906 under the instruction of the CPU 2001, and provides the detection values ​​of the various sensors to the CPU 2001.

[0027] Fig. 5 is a flowchart showing the generation process of UFB-containing liquid in the UFB-containing liquid manufacturing apparatus 2000 of this embodiment. The generation process of UFB-containing liquid in this embodiment will be described below with reference to the flowchart in Fig. 5. The series of processes shown in Fig. 5 are performed by the CPU 2001 of the UFB-containing liquid manufacturing apparatus 2000 expanding the 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. 5 may be realized by hardware such as an ASIC or electronic circuit. Note that the symbol "S" in the description of each process indicates that it is a step in the flowchart.

[0028] When the generation process of the UFB-containing liquid is started, the CPU 2001 stores a predetermined amount of liquid in the storage chamber 900 in S501. 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 W stored in the liquid supply unit 600 is sent to the storage chamber 900 while being degassed in the degassing unit 604. Then, 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 the liquid W is stored in the storage chamber 900. Thereafter, the CPU 2001 starts temperature control of the liquid W stored in the storage chamber 900 in S502. Specifically, the CPU 2001 drives the cooling unit 903 while monitoring the temperature detected by the temperature sensor 905. Then, when the temperature detected by the temperature sensor 905 becomes 10° C. or less, the CPU 2001 starts dissolving the gas in S503. Specifically, the gas dissolver 800 is driven, and the pump 702 is driven to start circulating the liquid W in the circulation path A.

[0029] Thereafter, in S504, when the solubility sensor 907 detects a predetermined solubility, the CPU 2001 performs UFB generation. Details of the UFB generation will be described later. Temperature control and gas solubility control are continuously performed while the UFB is being generated. That is, while monitoring the temperature sensor 905 and the solubility sensor 907, the drive of each part is started and stopped so that the temperature and gas solubility are within the predetermined range. Then, in S505, the CPU 2001 ends all drives, opens the valve 904, and collects the UFB-containing liquid, completing the process.

[0030] Fig. 6 is a flowchart showing the process of the UFB generating step (S504) in the generation process of the UFB-containing liquid shown in Fig. 5. Hereinafter, the details of the UFB generating step in the case where the UFB is generated continuously for a long period of time will be described with reference to the flowchart in Fig. 6.

[0031] When the UFB production process is started, the CPU 2001 drives the supply pump 703 and the recovery pump 704 under first conditions in S601 to circulate the liquid through the circulation path B. The CPU 2001 then drives the UFB production unit 1000 for a predetermined time in S602. The drive time is arbitrarily determined according to the drive frequency of the heating element 1102, and a table correlating the drive frequency with the drive time is stored in advance in the ROM. The CPU 2001 then stops the UFB production unit 1000 in S603, and then drives the supply pump 703 and the recovery pump 704 under second conditions for a predetermined time in S604. Here, the second conditions have a higher flow rate than the first conditions.

[0032] By circulating the liquid at a higher speed than under the first condition, the amount of liquid W passing through the UFB generation unit 1000 can be increased, thereby cooling the UFB generation unit 1000. As a result, the temperature rise of the liquid W in the UFB generation section can be suppressed, and the amount of gas dissolved in the liquid can be suppressed from decreasing. In this embodiment, the first condition (first mode) is set to 30 mL / min, and the second condition (second mode) is set to 300 mL / min. It is to be noted that the second condition is desirably set in consideration of the amount of heat generated by the heating element 1102 and the cooling capacity of the cooling section 903.

[0033] Thereafter, in S605, the CPU 2001 determines whether or not the UFB concentration in the UFB-containing liquid in the storage chamber 900 has reached a predetermined concentration based on the detection value of the UFB concentration sensor 906, and if the predetermined concentration has not been reached, the process returns to S601 and is repeated.

[0034] In this embodiment, it has been described that the supply pump 703 and the recovery pump 704 are driven for a predetermined time under the second condition after the UFB generation unit 1000 is stopped (S603), but this is not limited to this. The supply pump 703 and the recovery pump 704 may be driven for a predetermined time under the second condition while the UFB generation unit 1000 is still running.

[0035] In addition, the embodiment has been described using a UFB manufacturing apparatus using the T-UFB method as an example, but the generation method is not limited to this, and other methods can also be used. Also, the present invention can be applied not only to UFB manufacturing apparatuses of less than 1 μm, but also to microbubble manufacturing apparatuses of 1 to 100 μm.

[0036] In this way, the operation of the first mode in which the liquid between the ultra-fine bubble generating unit 1000 and the storage chamber 900 is circulated at a first flow velocity and the operation of the second mode in which the liquid is circulated at a second flow velocity faster than the first flow velocity are switched based on a predetermined condition. This makes it possible to provide an apparatus and a method for producing a UFB-containing liquid that can suppress a decrease in the UFB production efficiency during long-term operation.

[0037] Second embodiment The second embodiment of the present invention will be described below with reference to the drawings. Note that the basic configuration of this embodiment is similar to that of the first embodiment, so the following describes only the characteristic configuration. In this embodiment, the conditions of the supply pump 703 and the recovery pump 704 are switched and the UFB generation unit 1000 is driven and controlled based on the temperature detected by the temperature sensor 1107 on the heating element substrate 1100 .

[0038] Fig. 7 is a flowchart showing the process of the UFB generating step (S504) in the process of generating the UFB-containing solution in this embodiment shown in Fig. 5. Hereinafter, the UFB generating step in this embodiment will be described with reference to the flowchart in Fig. 7.

[0039] When the UFB generation process is started, in S701, the CPU 2001 drives the supply pump 703 and the recovery pump 704 under a first condition to circulate through the circulation path B. Thereafter, in S702, the CPU 2001 drives the UFB generation unit 1000. Then, in S703, the CPU 2001 determines whether the value of the temperature sensor 1107 has reached a preset upper limit value, and if not, repeats the generation and determination of UFB until the value has reached the upper limit value. When the value of the temperature sensor 1107 has reached the upper limit value, the CPU 2001 proceeds to S704 and stops driving the UFB generation unit 1000.

[0040] Thereafter, in S705, the CPU 2001 switches the supply pump 703 and the recovery pump 704 from the first condition to the second condition and drives them. This cools the UFB generation unit 1000. Then, in S706, the CPU 2001 determines whether the value of the temperature sensor 1107 has reached a preset lower limit, and if not, repeats the determination until it has reached the lower limit. At this time, the UFB generation unit 1000 is not driven. When the value of the temperature sensor 1107 has reached the lower limit, the CPU 2001 proceeds to S707 and determines whether the concentration of UFB in the UFB-containing liquid in the storage chamber 900 has reached a predetermined concentration based on the detection value of the UFB concentration sensor 906. If the predetermined concentration has not been reached, the process returns to S701 and is repeated. If the predetermined concentration has been reached, the process ends.

[0041] When the temperature sensor 1107 outputs a value exceeding the upper or lower limit, the drive may be switched immediately, but taking into account the effects of noise, the drive may be switched after confirming that the sensor has output a value exceeding the upper or lower limit for a certain period of time (e.g., about 0.5 seconds).

[0042] Fig. 8 shows a temperature rise profile obtained by actually measuring the temperature of UFB generation unit 1000 with the upper limit set to 50°C and the lower limit set to 35°C as detected by temperature sensor 1107, as an example of the second embodiment. Fig. 8(a) shows the temperature profile for a short period, and Fig. 8(b) shows the temperature profile for a long period. Since temperature sensor 1107 is attached to heating element substrate 1100, the temperature is actually that of heating element substrate 1100, but here it will be described as the temperature of UFB generation unit 1000 equipped with heating element substrate 1100.

[0043] As shown in Figure 8(a), the temperature of the UFB generation unit 1000 is maintained in the range of approximately 35 to 50°C while taking a comb-tooth-shaped profile, and it can be confirmed that the temperature is controlled within the desired temperature range even when operated continuously for more than ten hours.

[0044] In this embodiment, the drive of the supply pump 703, the recovery pump 704, and the UFB generation unit 1000 is controlled according to the value of the temperature sensor. Therefore, as described in the first embodiment, it is not necessary to store in advance in a ROM a table associating drive frequencies with drive times, and UFB generation can be freely performed under desired conditions.

[0045] Furthermore, when the heating element 1102 is driven for a long time, the temperature rise characteristics may change over time. However, if the driving control is performed according to the value of the temperature sensor 1107 as in this embodiment, rather than the driving time of the heating element, the temperature of the UFB generation unit 1000 can be accurately maintained within a constant range without being affected by changes over time.

[0046] 2, in the UFB generating unit 1000 equipped with multiple heating element substrates 1100, the values ​​of multiple temperature sensors 1107 are read. In this case, the drive control may be performed based on the average value of each sensor, or the highest value among the multiple sensors may be used as the set temperature upper limit, and the lowest value among the multiple sensors may be used as the set temperature lower limit.

[0047] (Third embodiment) The third 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 the characteristic configuration will be described below. In this embodiment, a process for removing air bubbles generated or mixed in the UFB generation unit 1000 is performed in the UFB generation process.

[0048] Fig. 9(a) is a flowchart showing the process of the UFB generation step in this embodiment, Fig. 9(b) is a flowchart showing the process in S901 in Fig. 9(a), and Fig. 9(c) is a flowchart showing the process in S903 in Fig. 9(a). The UFB generation step in this embodiment will be described below with reference to the flowcharts in Fig. 9(a) to (c).

[0049] First, the flowchart of FIG. 9(a) will be described. When the UFB production process is started, the CPU 2001 executes a first sequence in S901. The first sequence will be described in detail later. Then, the CPU 2001 determines in S902 whether the first sequence has been performed a predetermined number of times. If it has not been performed the predetermined number of times, the process returns to S901 and executes the first sequence again. If it has been performed the predetermined number of times, the CPU 2001 proceeds to S903 and executes a second sequence. The second sequence will be described in detail later. Then, in S904, the CPU 2001 determines whether the concentration of UFB in the UFB-containing liquid in the storage chamber 900 has reached a predetermined concentration based on the detection value of the UFB concentration sensor 906. If it has not reached the predetermined concentration, the process returns to S901 and repeats the process. If it has reached the predetermined concentration, the process ends.

[0050] As shown in FIG. 9B, the first sequence in S901 in FIG. 9A is similar to the processes in S701 to S706 in the flowchart described in FIG. 7 of the second embodiment, and therefore a description thereof will be omitted.

[0051] The second sequence in S903 in FIG. 9(a) will be described with reference to the flowchart in FIG. 9(c).

[0052] When the second sequence is started, the CPU 2001 drives the supply pump 703 and the recovery pump 704 under the first condition in S921 to circulate the liquid. Thereafter, the CPU 2001 drives the UFB generation unit 1000 for a predetermined time in S922. Then, the CPU 2001 stops the driving of the UFB generation unit 1000 in S923, and stops the driving of the supply pump 703 in S924. Then, the CPU 2001 closes the valve 1003 in S925. Next, the CPU 2001 switches the recovery pump 704 to the second condition and drives it for a predetermined time with the valve 1003 closed in S926, thereby sucking all of the liquid W inside the UFB generation unit 1000 (third mode). This also removes any air bubbles that have been generated and mixed in the UFB generation unit 1000. Then, the CPU 2001 opens the valve 1003 in S927. By opening valve 1003, the inside of UFB generation unit 1000 is filled with liquid W.

[0053] In this embodiment, even if the second condition in S926 is the same as the first condition, it is possible to remove air bubbles. However, in order to suck up the liquid W inside the UFB generation unit 1000 in a shorter time, it is desirable to set the flow rate faster in the second condition in S926 than in the first condition. This minimizes the time during which UFB generation is stopped, and allows efficient UFB generation.

[0054] In this way, by not only keeping the temperature of the UFB production unit 1000 within a specified range but also removing the air bubbles, the inhibition of foaming caused by the air bubbles is suppressed, and the UFB-containing liquid can be produced more stably.

[0055] The disclosure of this embodiment includes the following configurations and methods.

[0056] (Configuration 1) An ultra-fine bubble generating means capable of generating ultra-fine bubbles in a liquid; A circulation means for circulating liquid in a circulation path including the ultra-fine bubble generating means; A control means for controlling the ultra-fine bubble generating means and the circulating means; An apparatus for producing an ultra-fine bubble-containing liquid, comprising: The apparatus for producing ultra-fine bubble-containing liquid, wherein the control means switches between a first mode in which the liquid in the circulation path is circulated at a first flow velocity and a second mode in which the liquid is circulated at a second flow velocity faster than the first flow velocity, based on predetermined conditions.

[0057] (Configuration 2) 2. The apparatus for producing an ultra-fine bubble-containing liquid according to configuration 1, wherein the predetermined condition is a time for which the ultra-fine bubble generating means is driven.

[0058] (Configuration 3) The apparatus further includes a temperature detection means for detecting the temperature of the ultra-fine bubble generating means, 2. The apparatus for producing ultra-fine bubble-containing liquid according to configuration 1, wherein the predetermined condition is the temperature of the ultra-fine bubble generating means detected by the temperature detection means.

[0059] (Configuration 4) The apparatus for producing ultra-fine bubble-containing liquid according to configuration 3, wherein the control means switches from the first mode to the second mode when the temperature detected by the temperature detection means reaches a predetermined upper temperature limit.

[0060] (Configuration 5) The apparatus for producing ultra-fine bubble-containing liquid according to configuration 3, wherein the ultra-fine bubble generating means is provided with a plurality of the temperature detecting means, and when an average value of temperatures detected by the temperature detecting means reaches a predetermined upper temperature limit, the apparatus switches from the first mode to the second mode.

[0061] (Configuration 6) The apparatus for producing ultra-fine bubble-containing liquid according to configuration 3, wherein the ultra-fine bubble generating means is provided with a plurality of the temperature detecting means, and when the highest value of the temperature detected by the temperature detecting means reaches a predetermined upper temperature limit, the apparatus switches from the first mode to the second mode.

[0062] (Configuration 7) The apparatus for producing ultra-fine bubble-containing liquid according to configuration 3, wherein the control means terminates the operation in the second mode when the temperature detected by the temperature detection means reaches a predetermined lower limit temperature.

[0063] (Configuration 8) The apparatus for producing ultra-fine bubble-containing liquid according to configuration 3, wherein the ultra-fine bubble generating means comprises a plurality of the temperature detecting means, and when an average value of temperatures detected by the temperature detecting means reaches a predetermined lower limit temperature, the operation in the second mode is terminated.

[0064] (Configuration 9) The apparatus for producing ultra-fine bubble-containing liquid according to configuration 3, wherein the ultra-fine bubble generating means comprises a plurality of the temperature detecting means, and when the lowest value of the temperature detected by the temperature detecting means reaches a predetermined lower limit temperature, the operation in the second mode is terminated.

[0065] (Configuration 10) The circulation means is a circulation means arranged downstream of the ultra-fine bubble generating means in the circulation path for circulating the liquid in the circulation path; a blocking means arranged upstream of the ultra-fine bubble generating means in the circulation path and capable of switching between blocking and opening of the circulation path; having The apparatus for producing ultra-fine bubble-containing liquid according to configuration 1, wherein the control means executes a third mode in which the drive of the ultra-fine bubble generating means is stopped and the circulating means is driven in a state in which the blocking means is blocked.

[0066] (Configuration 11) 11. The apparatus for producing ultra-fine bubble-containing liquid according to any one of configurations 1 to 10, further comprising a container means arranged in the circulation path and capable of containing liquid.

[0067] (Configuration 12) 12. The apparatus for producing ultra-fine bubble-containing liquid according to claim 11, further comprising a stirring means for stirring the liquid contained in the container means.

[0068] (Configuration 13) 13. The apparatus for producing an ultra-fine bubble-containing liquid according to configuration 11 or 12, further comprising concentration detection means for detecting the concentration of ultra-fine bubbles in the liquid contained in the container means.

[0069] (Configuration 14) 14. The apparatus for producing ultra-fine bubble-containing liquid according to any one of configurations 11 to 13, further comprising a temperature control means for controlling the temperature of the liquid contained in the container means.

[0070] (Configuration 15) 15. The apparatus for producing an ultra-fine bubble-containing liquid according to any one of configurations 1 to 14, wherein the ultra-fine bubble generating means generates ultra-fine bubbles by heating a heating element to cause film boiling at the interface between the liquid and the heating element.

[0071] (Configuration 16) 16. The apparatus for producing ultra-fine bubble-containing liquid according to any one of configurations 1 to 15, further comprising a dissolving means for dissolving a predetermined gas in the liquid circulated through the circulation path.

[0072] (Method 1) an ultrafine bubble generating step of generating ultrafine bubbles in a liquid by an ultrafine bubble generating means; a circulation step of circulating a liquid in a circulation path including the ultra-fine bubble generating means; A method for producing an ultra-fine bubble-containing liquid, comprising: A method for producing an ultra-fine bubble-containing liquid, comprising switching between a first mode in which the liquid in the circulation path is circulated at a first flow velocity and a second mode in which the liquid is circulated at a second flow velocity faster than the first flow velocity, based on predetermined conditions. [Explanation of symbols]

[0073] 703 Supply Pump 704 Recovery Pump 900 Containment Room 903 Cooling section 1000 UFB Generating Units 1100 Heating element board 2001 CPU

Claims

1. an ultrafine bubble generating means capable of generating ultrafine bubbles in a liquid; a circulation means for circulating a liquid in a circulation path including the ultra-fine bubble generating means; a control means for controlling the ultra-fine bubble generating means and the circulating means; An apparatus for producing an ultra-fine bubble-containing liquid, comprising: the control means switches between a first mode in which the liquid in the circulation path is circulated at a first flow velocity and a second mode in which the liquid is circulated at a second flow velocity that is faster than the first flow velocity, based on a predetermined condition; The apparatus for producing an ultra-fine bubble-containing liquid, wherein the predetermined condition is the time for which the ultra-fine bubble generating means is driven.

2. An ultrafine bubble generating means capable of generating ultrafine bubbles in a liquid; a circulation means for circulating a liquid in a circulation path including the ultra-fine bubble generating means; a control means for controlling the ultra-fine bubble generating means and the circulating means; An apparatus for producing an ultra-fine bubble-containing liquid, comprising: the control means switches between a first mode in which the liquid in the circulation path is circulated at a first flow velocity and a second mode in which the liquid is circulated at a second flow velocity that is faster than the first flow velocity, based on a predetermined condition; Further provided is a temperature detection means for detecting the temperature of the ultra-fine bubble generating means, The apparatus for producing an ultra-fine bubble-containing liquid, wherein the predetermined condition is the temperature of the ultra-fine bubble generating means detected by the temperature detecting means.

3. 3. The apparatus for producing ultra-fine bubble-containing liquid according to claim 2, wherein the control means switches from the first mode to the second mode when the temperature detected by the temperature detection means reaches a predetermined upper temperature limit.

4. 3. The apparatus for producing an ultra-fine bubble-containing liquid according to claim 2, wherein the ultra-fine bubble generating means comprises a plurality of temperature detecting means, and when an average value of temperatures detected by the temperature detecting means reaches a predetermined upper temperature limit, the apparatus switches from the first mode to the second mode.

5. 3. The apparatus for producing ultra-fine bubble-containing liquid according to claim 2, wherein the ultra-fine bubble generating means comprises a plurality of temperature detecting means, and when the highest value of the temperature detected by the temperature detecting means reaches a predetermined upper temperature limit, the apparatus switches from the first mode to the second mode.

6. 3. The apparatus for producing ultra-fine bubble-containing liquid according to claim 2, wherein the control means terminates the operation in the second mode when the temperature detected by the temperature detection means reaches a predetermined lower limit temperature.

7. 3. The apparatus for producing ultra-fine bubble-containing liquid according to claim 2, wherein the ultra-fine bubble generating means comprises a plurality of temperature detecting means, and when the average value of the temperatures detected by the temperature detecting means reaches a predetermined lower limit temperature, the operation in the second mode is terminated.

8. 3. The apparatus for producing an ultra-fine bubble-containing liquid according to claim 2, wherein the ultra-fine bubble generating means comprises a plurality of temperature detecting means, and when the lowest temperature detected by the temperature detecting means reaches a predetermined lower limit temperature, the operation in the second mode is terminated.

9. The circulation means is a circulation means disposed downstream of the ultra-fine bubble generating means in the circulation path for circulating the liquid in the circulation path; a closing means arranged upstream of the ultra-fine bubble generating means in the circulation path, and capable of switching between closing and opening the circulation path; and 2. The apparatus for producing ultra-fine bubble-containing liquid according to claim 1, wherein the control means executes a third mode in which the drive of the ultra-fine bubble generating means is stopped and the circulating means is driven in a state in which the closing means is closed.

10. 2. The apparatus for producing an ultra-fine bubble-containing liquid according to claim 1, further comprising a container arranged in the circulation path and capable of containing a liquid.

11. 11. The apparatus for producing an ultra-fine bubble-containing liquid according to claim 10, further comprising a stirring means for stirring the liquid contained in the containing means.

12. 11. The apparatus for producing an ultra-fine bubble-containing liquid according to claim 10, further comprising concentration detection means for detecting the concentration of ultra-fine bubbles in the liquid contained in the containing means.

13. 11. The apparatus for producing ultra-fine bubble-containing liquid according to claim 10, further comprising a temperature control means for controlling the temperature of the liquid contained in the container means.

14. 2. The apparatus for producing an ultra-fine bubble-containing liquid according to claim 1, wherein the ultra-fine bubble generating means generates ultra-fine bubbles by generating heat in a heating element to cause film boiling at the interface between the liquid and the heating element.

15. 2. The apparatus for producing an ultra-fine bubble-containing liquid according to claim 1, further comprising a dissolving means for dissolving a predetermined gas in the liquid circulated through the circulation path.

16. an ultrafine bubble generating step of generating ultrafine bubbles in a liquid by an ultrafine bubble generating means; a circulation step of circulating a liquid in a circulation path including the ultra-fine bubble generating means; A method for producing an ultra-fine bubble-containing liquid, comprising: A method for producing an ultra-fine bubble-containing liquid, characterized in that the method switches between a first mode in which the liquid in the circulation path is circulated at a first flow velocity and a second mode in which the liquid is circulated at a second flow velocity that is faster than the first flow velocity, based on predetermined conditions.

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