EP4691617A1 - Bubble concentration adjustment device and tank system - Google Patents

Bubble concentration adjustment device and tank system

Info

Publication number
EP4691617A1
EP4691617A1 EP24784867.4A EP24784867A EP4691617A1 EP 4691617 A1 EP4691617 A1 EP 4691617A1 EP 24784867 A EP24784867 A EP 24784867A EP 4691617 A1 EP4691617 A1 EP 4691617A1
Authority
EP
European Patent Office
Prior art keywords
liquid
bubble
flow rate
flow path
adjustment device
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP24784867.4A
Other languages
German (de)
French (fr)
Inventor
Masahito HOMMA
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Bizser Co Ltd
Original Assignee
Bizser Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Bizser Co Ltd filed Critical Bizser Co Ltd
Publication of EP4691617A1 publication Critical patent/EP4691617A1/en
Pending legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
    • B01F23/20—Mixing gases with liquids
    • B01F23/23—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids
    • B01F23/237—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids characterised by the physical or chemical properties of gases or vapours introduced in the liquid media
    • B01F23/2373—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids characterised by the physical or chemical properties of gases or vapours introduced in the liquid media for obtaining fine bubbles, i.e. bubbles with a size below 100 µm
    • B01F23/2375—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids characterised by the physical or chemical properties of gases or vapours introduced in the liquid media for obtaining fine bubbles, i.e. bubbles with a size below 100 µm for obtaining bubbles with a size below 1 µm
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/40—Static mixers
    • B01F25/42—Static mixers in which the mixing is affected by moving the components jointly in changing directions, e.g. in tubes provided with baffles or obstructions
    • B01F25/43—Mixing tubes, e.g. wherein the material is moved in a radial or partly reversed direction
    • B01F25/431—Straight mixing tubes with baffles or obstructions that do not cause substantial pressure drop; Baffles therefor
    • B01F25/4319—Tubular elements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/40—Static mixers
    • B01F25/42—Static mixers in which the mixing is affected by moving the components jointly in changing directions, e.g. in tubes provided with baffles or obstructions
    • B01F25/43—Mixing tubes, e.g. wherein the material is moved in a radial or partly reversed direction
    • B01F25/431—Straight mixing tubes with baffles or obstructions that do not cause substantial pressure drop; Baffles therefor
    • B01F25/43197—Straight mixing tubes with baffles or obstructions that do not cause substantial pressure drop; Baffles therefor characterised by the mounting of the baffles or obstructions
    • B01F25/431971—Mounted on the wall
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/40—Static mixers
    • B01F25/42—Static mixers in which the mixing is affected by moving the components jointly in changing directions, e.g. in tubes provided with baffles or obstructions
    • B01F25/43—Mixing tubes, e.g. wherein the material is moved in a radial or partly reversed direction
    • B01F25/433—Mixing tubes wherein the shape of the tube influences the mixing, e.g. mixing tubes with varying cross-section or provided with inwardly extending profiles
    • B01F25/4335—Mixers with a converging-diverging cross-section
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
    • B01F35/80—Forming a predetermined ratio of the substances to be mixed
    • B01F35/81—Forming mixtures with changing ratios or gradients
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
    • B01F35/80—Forming a predetermined ratio of the substances to be mixed
    • B01F35/83—Forming a predetermined ratio of the substances to be mixed by controlling the ratio of two or more flows, e.g. using flow sensing or flow controlling devices

Definitions

  • the present invention relates to a bubble concentration adjustment device and a tank system.
  • Patent Document 1 discloses a proposal in which a bubble generating device is provided in a tank installed in the circulation system of an air-conditioning system, and contaminants in the circulation system are removed using the gas-liquid mixture stored in the tank.
  • Patent Document 1 JP 2008-190754 A
  • An object of the present invention is to provide a bubble concentration adjustment device and a tank system that make it possible to adjust a bubble concentration contained in a bubble-containing liquid.
  • the present invention is characterized by the following items (1) to (6).
  • the bubble concentration adjustment device has a structure for controlling the amount of bubbles (bubble concentration) contained in a liquid having bubbles.
  • a bubble concentration adjustment device 10 includes a plurality of flow paths 11, a flow rate ratio control unit 12, and a bubble generating unit 13.
  • the flow paths 11 are configured so as to allow liquid to flow therethrough, and specifically, they can be exemplified by a structure formed with pipe members 20.
  • the sizes of the plurality of flow paths 11 i.e., the size of the longitudinal cross section of each flow path 11, taken in a plane perpendicular to the longitudinal direction of the flow path 11
  • the number of the flow paths 11 is not particularly limited, and may be two or three or more. In the example shown in FIG. 1 , two flow paths 11 are provided, and when these two flow paths 11 are referred to as a first flow path 11A and a second flow path 11B, both are composed of pipe members 20 having the same longitudinal cross-sectional size. That is, the example in FIG.
  • FIG. 1 illustrates a case in which the plurality of flow paths 11 have the same longitudinal cross-sectional size.
  • an arrow F indicates a flow of liquid flowing in from an inlet 14, which will be described later;
  • an arrow FP1 indicates a flow of liquid through the first flow path 11A;
  • an arrow FP2 indicates a flow of liquid through the second flow path 11B.
  • an inlet 14 for receiving liquid is formed, as shown in the example of FIG. 1 , and liquid from an external liquid supply source (not shown) can be introduced through the inlet 14.
  • the liquid poured in the direction of arrow F from the inlet 14 can flow from the upstream end to the downstream end through any of the flow paths 11.
  • the inlet 14 may be formed individually for each of the plurality of flow paths 11, the inlet 14 is preferably common to the plurality of flow paths 11.
  • the expression that the inlet 14 is common means that the liquid flowing through any of the plurality of flow paths 11 is supplied from the same inlet 14.
  • the inlet is specified as a single inlet, as shown in FIG. 1 . If there is a single inlet, it becomes easier to adjust the bubble concentration of the liquid (i.e., the mixed liquid determined assuming the overall liquid flowing out from the outlet) obtained via the bubble concentration adjustment device 10 by controlling the flow of liquid introduced through the single inlet.
  • the liquid stably flows from an external liquid supply source into the flow paths 11 through the inlet 14 while satisfying a predetermined range of pressure, flow velocity, and flow rate. From the viewpoint of achieving this more reliably, when using the bubble concentration adjustment device 10, it is preferable to adopt, as a structure (hereinafter referred to as a flow-in assistance structure) for causing the liquid to flow from the inlet 14 toward the flow paths 11, a structure in which a device such as a pump is disposed outside the inlet 14, or a structure in which the supply source is located at a position higher than a predetermined level above the inlet 14.
  • a structure hereinafter referred to as a flow-in assistance structure
  • the presence of a flow-in assistance structure when using the bubble concentration adjustment device 10 can exhibit particularly high effectiveness in the case where the bubble generating unit 13, which will be described later, is a cavitation-type device (bubble generating device). This is because, when the bubble generating unit is a cavitation-type device, the bubble generating device can more reliably generate bubbles in the liquid-such as fine bubbles (including ultrafine bubbles and microbubbles), which will be described later-if the liquid supplied to the bubble generating device has a pressure, flow velocity, and flow rate that satisfy a predetermined range.
  • the bubble concentration adjustment device 10 includes a receiving flow path 15 that is formed with an inlet 14 at its upstream end and is configured to receive the liquid flowing in through the inlet 14.
  • the downstream end of the receiving flow path 15 i.e., the end opposite to the inlet 14 along the direction of arrow F
  • the first flow path 11A and the second flow path 11B are connected to the receiving flow path 15 via a flow rate control member 16, which will be described later. That is, in the example of FIG.
  • the bubble concentration adjustment device 10 is configured such that the receiving flow path 15 is connected at its downstream end to the flow rate control member 16, and the flow rate control member 16 branches into the first flow path 11A and the second flow path 11B.
  • the liquid flowing through either the first flow path 11A or the second flow path 11B flows in from the common inlet 14.
  • the arrangement of the receiving flow path 15 and the plurality of flow paths 11 shown in FIG. 1 is merely an example and is not limited thereto.
  • the receiving flow path 15 may be integrated with either the first flow path 11A or the second flow path 11B.
  • a part of the first flow path 11A or a part of the second flow path 11B serves also as the receiving flow path 15, forming a structure in which the second flow path 11B branches from the first flow path 11A, or conversely, the first flow path 11A branches from the second flow path 11B.
  • the receiving flow path 15 may be provided with the above-described flow-in assistance structure.
  • a pump or the like may be provided in the middle of the receiving flow path 15. By providing a pump or the like in the middle of the receiving flow path 15, it becomes easier to stabilize the pressure, flow velocity, and flow rate of the liquid flowing through the receiving flow path 15 within a predetermined range.
  • the liquid flowing through the flow paths 11 is not particularly limited, and examples thereof include a solvent, or a substance in which a compound or the like is dissolved, dispersed, or mixed in the solvent (e.g., a solution, dispersion, or mixture).
  • the solvent include water and organic solvents. Examples of water include tap water, well water, seawater, purified water, ultrapure water, and water that has undergone a supercritical state (supercritical-state-passed water). Examples of organic solvents include alcohols and oils.
  • Examples of compounds or the like that can be dissolved in the solvent include inorganic compounds such as covalent substances like carbon dioxide, nitrogen, and oxygen; inorganic electrolytes such as sodium chloride; and various organic compounds such as aliphatic hydrocarbons, aromatic hydrocarbons, alcohols, peptides, and fatty acids.
  • the liquid flowing through the flow paths 11 may be determined according to the intended use of a gas-liquid mixture containing fine bubbles or ultrafine bubbles as bubbles.
  • the intended use of the gas-liquid mixture may be determined in accordance with the effects thereof.
  • the effects of incorporating fine bubbles or ultrafine bubbles as bubbles into a liquid include effects related to solubility, separability, washability, fluidity, and improvement in the quality of medical treatment and diagnostics. Effects related to solubility due to bubbles include: improvement in the effectiveness of ozonated water; enhanced miscibility of oil and additives; promotion of emulsification of oil and water; oxygen enrichment of liquid fertilizers by containing oxygen-containing bubbles; and improvement of water quality for fish farming.
  • Effects related to separability due to bubbles include soil purification and water purification. Effects related to washability include improved cleaning performance of precision instruments, home appliances, food materials, and human bodies, as well as enhanced cleaning performance in cleaning processes in production lines.
  • An effect related to efficiency improvement due to bubbles includes conversion into fuel by promoting emulsification of oil (e.g., waste oil) and water using bubbles. Effects related to the improvement in the quality of medical treatment and diagnostics include enhancement of the effectiveness of ultrasonic therapy through the combined use of ultrasound and bubbles.
  • the bubble concentration adjustment device 10 is applicable to cases where a gas-liquid mixture is generated in order to achieve various effects produced by bubbles.
  • the liquid flowing through the bubble concentration adjustment device 10 includes liquids used to generate such a gas-liquid mixture for achieving the various effects produced by the bubbles.
  • Examples of the liquid flowing through the flow paths 11 include: liquids used in food products such as juices and sugar water; cleaning solutions used in hospitals and the like; medical liquids such as physiological saline; and various liquid fuels such as gasoline, diesel fuel, kerosene, and jet fuel.
  • the flow rate ratio control unit 12 provided in the bubble concentration adjustment device 10 includes a flow rate control member 16.
  • the flow rate ratio control unit 12 is indicated by a dashed line for convenience of explanation. This also applies to FIGS. 3 and 4 , and the like.
  • the flow rate ratio control unit 12 is a component for adjusting the flow rate of the liquid flowing through the flow paths 11. That is, the flow rate ratio control unit 12 may also be referred to as a flow rate ratio variable section.
  • the flow rate ratio control unit 12 is capable of changing a flow rate ratio of the liquid flowing through the plurality of flow paths 11 so as to allow adjustment of the concentration (bubble concentration) of bubbles by mixing the liquid flowing out of the plurality of flow paths 11.
  • the flow rate (cm 3 /sec) of the liquid flowing through each flow path 11 refers to the volume (cm 3 ) of liquid flowing into the flow path per unit time (sec). In the example shown in FIG.
  • the flow rate ratio is given as the ratio of the amount (flow rate) of liquid flowing through the first flow path to the amount (flow rate) of liquid flowing through the second flow path from among the liquid introduced through the inlet.
  • the flow rate ratio is defined as WA:WB, where WA is the amount (flow rate) of the liquid flowing through the first flow path, and WB is the amount (flow rate) of the liquid flowing through the second flow path.
  • WA the amount (flow rate) of the liquid flowing through the first flow path
  • WB is the amount (flow rate) of the liquid flowing through the second flow path.
  • the flow rate ratio control unit 12 controls (changes) the flow rate ratio so as to allow adjustment of the concentration of fine bubbles (sometimes referred to as "fine bubble concentration”) or the concentration of ultrafine bubbles (sometimes referred to as "ultrafine bubble concentration”), which will be described later.
  • the flow rate ratio control unit 12 is configured to be capable of changing the flow rate ratio in accordance with the bubble concentration of the entire liquid discharged per unit time from the outlet.
  • the flow rate ratio control unit 12 is not particularly limited as long as it has a structure capable of changing and controlling the flow rate of the liquid flowing through each of the flow paths 11. In the example shown in FIG. 1 , it corresponds to a portion having a distribution valve 21.
  • the "entire liquid discharged per unit time" refers to the combined liquid consisting of the liquid discharged per unit time from the outlet of the first flow path 11A and the liquid discharged per unit time from the outlet of the second flow path 11B.
  • the flow rate control member 16 is a member capable of controlling the flow of liquid through the flow path 11.
  • the flow rate control member 16 is the distribution valve 21.
  • the distribution valve 21 shown in the example of FIG. 1 is provided at a position connected to the downstream end of the receiving flow path 15 and to the upstream ends of the first flow path 11A and the second flow path 11B.
  • the distribution valve 21 controls a distribution ratio of the liquid supplied from the inlet 14 to each of the plurality of flow paths 11.
  • the structure of the distribution valve 21 is not particularly limited as long as it has a structure capable of changing the ratio of the amount of liquid flowing into the first flow path 11A to the amount of liquid flowing into the second flow path 11B (i.e., a structure capable of changing the distribution ratio).
  • the distribution valve 21 is configured so as to be capable of changing the ratio of the amount (flow rate WA) of liquid flowing into the first flow path and the amount (flow rate WB) of liquid flowing into the second flow path with respect to the total flow rate (WT) of liquid flowing from the inlet 14 into the receiving flow path 15, that is, the ratio (WA/WT):(WB/WT).
  • the flow rate ratio generally corresponds to the distribution ratio, and a change in the flow rate ratio is achieved by controlling (e.g., changing) the distribution ratio.
  • the concentration of fine bubbles generated in the liquid passing through the bubble generating unit is said to depend on the flow velocity, pressure, and flow rate of the liquid. Therefore, when the bubble generating unit is a cavitation-type device, if the flow velocity, pressure, or flow rate of the liquid supplied to the inlet 14 differs, or if the inner diameter of the pipe member 20 differs between the first flow path 11A and the second flow path 11B, the bubble concentration in the entire liquid flowing out of the outlet of the bubble concentration adjustment device 10 may differ, even with the same distribution ratio.
  • the flow rate ratio control unit 12 be configured to be capable of controlling the flow rate ratio of the liquid flowing through the plurality of flow paths 11 in accordance with the pressure, flow velocity, and flow rate of the liquid received from the inlet 14.
  • At least one of the plurality of flow paths 11 is provided with a bubble generating unit 13.
  • the bubble generating unit 13 generates bubbles in the liquid flowing through the flow path 11 in which it is provided.
  • the bubble generating unit 13 is provided in the first flow path 11A, and generates bubbles in the liquid flowing through the first flow path 11A.
  • the liquid flowing through the first flow path 11A becomes a gas-liquid mixture in which bubbles are dispersed in the liquid component after passing through the bubble generating unit 13.
  • At least a portion of the bubbles generated by the bubble generating unit 13 has a bubble diameter of less than 1 ⁇ m (that is, the average bubble diameter of at least some of the bubbles is less than 1 ⁇ m). However, it is preferable that all the bubbles generated by the bubble generating unit 13 have a diameter of less than 1 ⁇ m (that is, the average bubble diameter of all the generated bubbles is less than 1 ⁇ m).
  • Bubbles having a diameter of 100 ⁇ m or less may be referred to as “fine bubbles.”
  • bubbles having a diameter of 1 ⁇ m or more and 100 ⁇ m or less may be referred to as “microbubbles”
  • bubbles having a diameter of less than 1 ⁇ m may be referred to as “ultrafine bubbles” or “nanobubbles.”
  • the term “fine bubbles” is used herein to collectively refer to both microbubbles and ultrafine bubbles. It is preferable that at least some of the bubbles generated by the bubble generating unit 13 are ultrafine bubbles. For example, in the example shown in FIG.
  • the bubbles generated by the bubble generating unit 13 in the liquid flowing through the first flow path 11A are ultrafine bubbles.
  • the gas-liquid mixture as the liquid containing bubbles formed in the first flow path 11A, is in a state where ultrafine bubbles are dispersed in the liquid. In addition, this does not exclude the possibility that the gas-liquid mixture formed in the first flow path 11A contains bubbles other than ultrafine bubbles, and microbubbles or the like may also be included in the gas-liquid mixture.
  • the gas components inside the bubbles generated by the bubble generating unit 13 are not particularly limited. They may be gases introduced from outside into the bubble generating unit 13, or may be gasifiable components dissolved in the liquid supplied to the bubble generating unit 13.
  • the gasifiable components dissolved in the liquid may include dissolved carbon dioxide, dissolved oxygen (oxygen that was dissolved in water), and dissolved nitrogen (nitrogen that was dissolved in water), among others.
  • the bubble diameter refers to the diameter of a bubble.
  • the average bubble diameter refers to the average value of the diameters of the bubbles.
  • the average bubble diameter can be determined from the bubble diameter distribution.
  • the average bubble diameter of a portion of the bubbles can also be determined from the bubble diameter distribution.
  • the bubble diameter can be determined when measuring the bubble diameter distribution.
  • the bubble diameter and the average bubble diameter can be determined using techniques for measuring the bubble diameter distribution (particle size distribution) of the bubbles contained in the gas-liquid mixture. Examples of techniques for measuring the bubble diameter distribution (particle size distribution) include methods using laser diffraction/scattering type particle size distribution measuring devices. In addition, examples of methods for determining the bubble diameter distribution include particle size analysis based on the particle tracking analysis method conforming to JIS Z 8829:2021.
  • the bubble concentration (number of bubbles per cm 3 ) in the gas-liquid mixture generated by the bubble generating unit 13 is not particularly limited. However, even in the case where a mixed liquid is assumed that dilutes the bubble concentration by mixing the liquids flowing out of the plurality of flow paths 11 (that is, in the example of FIG.
  • the bubble concentration of bubbles having a diameter of less than 1 ⁇ m in the gas-liquid mixture is 20 million bubbles/cm 3 or more, more preferably 50 million bubbles/cm 3 , and still more preferably 60 million bubbles/cm 3 or more. If the liquid contains 20 million bubbles/cm 3 or more of bubbles having a diameter of less than 1 ⁇ m, the gas-liquid mixture can exhibit an anti-fouling effect.
  • the number of such bubbles is 50 million bubbles/cm 3 or more, it can exhibit a cleaning effect on biofilms (aggregates formed on solid surfaces by microorganisms, etc.). If the number of such bubbles is 60 million bubbles/cm 3 or more, these effects can be further enhanced. Since the bubble concentration of the mixed liquid can be increased up to the bubble concentration of the gas-liquid mixture, the effects obtained in the case where the gas-liquid mixture satisfies the above bubble concentration range can also be realized in the mixed liquid.
  • the upper limit of the bubble concentration in the gas-liquid mixture generated by the bubble generating unit 13 is not particularly limited. However, from the viewpoint of ease of stable bubble generation, it is preferable that the upper limit of the bubble concentration in the gas-liquid mixture be 5 billion bubbles/cm 3 .
  • the bubble concentration can be determined using the same methods exemplified above for specifying the bubble diameter or average bubble diameter of the bubbles.
  • the expression that the bubble concentration is preferably K 1 (bubbles/cm 3 ) or more means that the lower limit of the bubble concentration is preferably K 1 (bubbles/cm 3 ), and the bubble concentration (bubbles/cm 3 ) may be within a range defined by its lower and upper limits.
  • the bubbles contained in the gas-liquid mixture have a negative electric potential.
  • the negatively charged state of the bubbles can be realized depending on the magnitude of static electricity generated by cavitation in the liquid flowing through the flow path of the bubble generating unit 13-which will be described later-when it is a cavitation-type bubble generating device (e.g., the bubble generating device 100), and by friction of the fluid within the flow path (i.e., friction between the member forming the flow path and the bubbles).
  • the magnitude of the negative potential can be determined depending on various conditions, such as the diameter of the bubbles.
  • the gas-liquid mixture can be produced, for example, by allowing the liquid component serving as the raw material of the gas-liquid mixture to pass through the bubble generating unit 13.
  • the bubble generating unit 13 is configured to be capable of generating fine bubbles, such as ultrafine bubbles, in a liquid as bubbles, and forming a gas-liquid mixture in which the bubbles are dispersed in the liquid.
  • a bubble generating unit it is possible to exemplify a device (bubble generating device) that applies, as necessary, various types of bubble generating mechanisms such as cavitation type, microporous type, ultrasonic type, swirling flow type, static mixer type, Venturi type, steam condensation type, pressurized dissolution type, and gas-liquid mixing shear type.
  • a cavitation-type device As a cavitation-type device, a device such as that shown in the following "Example of a Bubble Generating Device" can be used. Next, an example of a bubble generating device that can be applied as the bubble generating unit 13 will be described with reference to FIGS. 2A to 2D .
  • a bubble generating device 100 includes: a receiving unit 110 for receiving a liquid component serving as the raw material (referred to as "raw material liquid”); a bubble generating mechanism 120 for generating a gas-liquid mixture in which bubbles are dispersed in the raw material liquid supplied from the receiving unit 110; and a discharge unit 130 for discharging the gas-liquid mixture.
  • FIGS. 2A to 2D illustrate one example of a bubble generating device.
  • FIG. 2D is a schematic enlarged cross-sectional view showing an enlarged portion of the region SP enclosed by a dashed line in FIG. 2C .
  • the raw material liquid is the liquid flowing through the first flow path 11A among the liquid supplied from the inlet 14.
  • the gas-liquid mixture flowing out from the discharge unit 130 further flows toward the outlet (not shown) of the first flow path 11A.
  • the bubble generating mechanism 120 includes a flow path forming body 121 and a plurality of collision elements 124.
  • the flow path forming body 121 forms a liquid flow path 122 on its inner peripheral surface 121A and includes a constricted structure 123.
  • the constricted structure 123 includes a first portion 123A, in which the cross-sectional diameter (as determined in a cross section taken on a plane perpendicular to the longitudinal direction of the liquid flow path 122) of the inner peripheral surface 121A decreases from the upstream end 125 (inlet) toward the downstream end 126 (outlet), and a second portion 123B, in which the cross-sectional diameter of the inner peripheral surface 121A increases from the upstream end 125 toward the downstream end 126.
  • the first portion 123A is located upstream of the second portion 123B.
  • the plurality of collision elements 124 protrude inward from the inner peripheral surface 121A of the flow path forming body 121 and are arranged adjacent to each other across a segment region 150.
  • the collision elements 124 are disposed at a position between (or at the boundary of) the first portion 123A and the second portion 123B in the longitudinal direction of the liquid flow path 122. However, this does not preclude the possibility that the collision elements 124 are formed in either the first portion 123A or the second portion 123B.
  • the segment region 150 refers to a region in the cross section of the inner peripheral surface 121A that is divided in the circumferential direction by adjacent collision elements 124.
  • the collision elements 124 are arranged to form a gap portion 151 that narrows the flow path between their tips.
  • the bubble generating mechanism 120 is configured such that the flow path forming body 121 allows the raw material liquid to pass from the upstream end 125 to the downstream end 126.
  • a pump for supplying the raw material liquid is installed on the upstream side and/or the downstream side of the bubble generating device 100.
  • This pump supplies the raw material liquid to the bubble generating device 100 so that the water pressure, flow velocity, and flow rate of the raw material liquid each reach or exceed a predetermined value.
  • the concentration of fine bubbles (such as microbubbles and ultrafine bubbles) generated varies depending on the pressure, flow velocity, and flow rate of the liquid flowing through the liquid flow path 122.
  • the bubble generating device 100 can generate a high concentration of fine bubbles in the liquid when at least one of the pressure, flow velocity, or flow rate of the liquid is increased.
  • a bubble-containing liquid can be obtained as described below.
  • the raw material liquid is injected into the receiving unit 110 of the bubble generating device 100 as a liquid fluid.
  • the receiving unit 110 is connected to the upstream end 125 (inlet) of the bubble generating mechanism 120, and the raw material liquid flows into the bubble generating mechanism 120 from the upstream end 125.
  • the flow velocity of the raw material liquid is increased by moving through the first portion 123A of the constricted structure 123 in a direction generally from the upstream end 125 to the downstream end 126 (in the direction of arrow LF).
  • the liquid proceeds to the gap portion 151 formed at the position where the collision elements 124 are arranged, and a portion of the raw material liquid further proceeds through the gap portion 151 toward the downstream end 126. At this time, another portion of the raw material liquid flows from the segment region 150 toward the downstream end 126, which prevents excessive increase in fluid resistance in the constricted structure 123 and enhances the negative pressure generation effect. As part of the raw material liquid passes through the gap portion 151, a cavitation effect occurs in the raw material liquid, causing dissolved components (e.g., dissolved oxygen) in the raw material liquid to be gasified into bubbles.
  • the bubble size is adjusted according to the size of the gap portion 151 and the structure of the collision elements 124. In this way, a gas-liquid mixture is produced in which bubbles having a desired diameter are dispersed in the raw material liquid.
  • the produced gas-liquid mixture flows out through the downstream end 126 via the discharge unit 130.
  • the bubbles dispersed in the gas-liquid mixture obtained by the bubble generating device 100 are, as described above, formed by cavitation that occurs in the raw material liquid, and are gasified components that result from the cavitation of constituents dissolved in the raw material liquid.
  • gasified oxygen (dissolved oxygen) and nitrogen (dissolved nitrogen) originally dissolved in the water constituting the raw material liquid are contained.
  • the gaseous components in the bubbles may be determined in accordance with the intended effect expected from the gas-liquid mixture. For example, when the gas-liquid mixture is used to achieve an effect of removing biofilms, it is preferable that the oxygen content within the bubbles be low. In consideration of further enhancing the desired effect, it is preferable that the bubble generating device 100 be equipped with a gas supply structure.
  • the bubble generating device 100 may be provided with a gas supply structure (not shown) for introducing a gas into the liquid flow path 122 from the outside, depending on the circumstances such as the effect required of the gas-liquid mixture, as described above.
  • a gas supply structure (not shown) for introducing a gas into the liquid flow path 122 from the outside, depending on the circumstances such as the effect required of the gas-liquid mixture, as described above.
  • the bubble generating device 100 is used as the bubble generating unit 13 or 280 in the examples shown in FIG. 1 , FIGS. 3A to 3D , FIGS. 4A to 4C , and FIGS. 6 to 10 , where the gas supply structure may be provided as needed.
  • the bubble generating device 100 When the bubble generating device 100 is equipped with a gas supply structure that introduces an external gas (e.g., nitrogen or carbon dioxide) into the liquid flow path 122, the supplied gas is incorporated into the raw material liquid at the point of introduction in the form of bubbles and flows toward the downstream end 126 along with the flow of the raw material liquid.
  • the bubbles formed from the gas supplied into the raw material liquid via the gas supply structure are finely divided by collisions with the collision elements 124 or the like, in the gap section 151 or the segment region 150, and are further refined. As a result, the bubbles can be reduced in size, for example, to a diameter of less than 1 ⁇ m.
  • the bubble generating device 100 described above can be applied as the bubble generating unit 13 of the bubble concentration adjustment device 10.
  • outlets (not shown) for the liquid that has flowed through the flow paths 11 are provided at the downstream ends of the plurality of flow paths 11.
  • an outlet is formed at the downstream end of the first flow path for the liquid that has flowed through the first flow path in the direction of arrow FP1
  • an outlet is formed at the downstream end of the second flow path for the liquid that has flowed through the second flow path in the direction of arrow FP2.
  • the first and second flow paths are not connected to each other at their respective downstream ends, and each has its own outlet.
  • the liquid supplied from the inlet 14 to the receiving flow path 15 is distributed to the plurality of flow paths 11 (the first flow path 11A and the second flow path 11B) by the flow rate ratio control unit 12, and the amount (flow rate) of liquid flowing through each flow path 11 is determined according to the control of the flow rate ratio.
  • At least one of the flow paths 11 (the first flow path 11A) is provided with a bubble generating unit 13, and bubbles are generated in the liquid flowing through the bubble generating unit 13. Since the flow rate of the liquid flowing through the flow path 11 (the first flow path 11A) provided with the bubble generating unit 13 is determined according to the state of flow rate ratio control by the flow rate ratio control unit 12, the amount of bubbles generated in the liquid is also determined.
  • the bubble concentration in the mixed liquid which is assumed to be a combination of the liquids flowing out of the outlets of the plurality of flow paths 11, is determined. That is, according to the bubble concentration adjustment device 10 described above, the concentration of bubbles in the liquid obtained by mixing the liquids flowing out of the outlet of the bubble concentration adjustment device 10 is determined according to the control of the flow rate ratio by the flow rate ratio control unit 12. Therefore, according to the bubble concentration adjustment device 10, it is possible to obtain a liquid having a desired bubble concentration by controlling the flow rate ratio.
  • the concentration of fine bubbles can be adjusted by mixing the liquid containing a high concentration of fine bubbles, which has passed through the bubble generating unit 13 of the first flow path 11A, and the liquid that has flowed through the second flow path 11B branched by the distribution valve 21, thereby diluting the liquid containing the high concentration of fine bubbles. Therefore, as in the conventional technique, in which the concentration of fine bubbles in the liquid is adjusted solely by the bubble generating device without using a structure such as the distribution valve 21, the bubble concentration adjustment device 10 makes it possible to obtain a large amount of liquid containing fine bubbles at an adjusted concentration.
  • the above-described liquid containing fine bubbles obtained by the bubble concentration adjustment device 10 contains, at least partially, microfine bubbles.
  • the bubble concentration adjustment device 10 it is possible to obtain a liquid containing fine bubbles at a desired concentration (containing, at least partially, microfine bubbles) while maintaining the flow rate of the liquid flowing in from the inlet, thereby suppressing the possibility of a reduction in the amount that can be supplied to the tank or the like per unit time.
  • FIG. 3A is a schematic diagram illustrating one example of the bubble concentration adjustment device 10A according to Modified Example 1.
  • the first flow path 11A and the second flow path 11B are connected at a position SC on the downstream side of the bubble generating unit 13 in the first flow path 11A.
  • the downstream position SC is a location at which the liquids that have flowed through the plurality of flow paths 11 merge on the downstream side.
  • bubble generating units 13 may be provided in the plurality of flow paths 11. This is referred to as Modified Example 2.
  • FIG. 3B is a schematic diagram illustrating one example of the bubble concentration adjustment device 10B according to Modified Example 2.
  • the bubble generating units 13 are provided in the first flow path 11A and the second flow path 11B.
  • the bubble generating units 13 may be provided in two of the flow paths 11, or in all three of the flow paths 11 (none of which is shown).
  • fine bubbles can be generated at a higher concentration in the liquid having a greater flow velocity and/or flow rate. This is particularly more feasible when the bubble generating unit is a cavitation-type device.
  • the flow rate ratio control unit 12 has a structure in which the flow rate control member 16 is provided so as to connect the lower end of the receiving flow path 15 to the upstream ends of the first flow path 11A and the second flow path 11B.
  • the flow rate ratio control unit 12 is not limited to this configuration.
  • the flow rate control member 16 in the flow rate ratio control unit 12 may be provided at a position offset from the lower end position of the receiving flow path 15. This is referred to as Modified Example 3.
  • FIG. 3C is a schematic diagram illustrating one example of the bubble concentration adjustment device 10C according to Modified Example 3.
  • the receiving flow path is integrated with the first flow path, and a portion extending from the upstream end of the first flow path to a predetermined position SV along the longitudinal direction of the first flow path serves also as the receiving flow path.
  • the predetermined position SV of the first flow path is a position where the second flow path branches from the first flow path.
  • the upstream end of the second flow path is connected to the predetermined position SV of the first flow path.
  • the flow rate ratio control unit 12 is composed of the flow rate control member 16 and a structure in which the second flow path branches from the first flow path.
  • a control valve 22 is provided instead of the distribution valve 21 shown in the example of FIG. 1 .
  • the control valve 22 is a valve for controlling the flow rate of the liquid flowing through the flow path 11 in which it is installed, and preferably has a function of opening and closing the flow path 11.
  • the control valve 22, which serves as the flow rate control member 16 is provided in the second flow path 11B and controls the amount of liquid flowing in the direction of arrow FP2 toward the downstream end within the second flow path 11B.
  • the ratio between the amount of liquid flowing through the first flow path 11A and the amount of liquid flowing through the second flow path 11B is determined by the control of the control valve 22.
  • control valve 22 was provided in the second flow path 11B.
  • the control valve 22 may alternatively be provided in the first flow path 11A.
  • the ratio between the amount of liquid flowing through the first flow path 11A and the amount of liquid flowing through the second flow path 11B is determined by the control of the control valve 22.
  • the control valve 22 may also be provided in both the first flow path 11A and the second flow path 11B.
  • the flow rate ratio control unit 12 includes a plurality of flow rate control members 16, and the plurality of flow rate control members 16 include a plurality of control valves 22.
  • the flow rate ratio control unit 12 may include an operation unit 42, and the operation unit 42 may be provided with a scale display unit 40 having a scale 41 as a concentration display unit that indicates a bubble concentration corresponding to the flow rate ratio.
  • a scale display unit 40 having a scale 41 as a concentration display unit that indicates a bubble concentration corresponding to the flow rate ratio.
  • FIG. 5A is a diagram illustrating an example of the scale display unit 40 of the flow rate ratio control unit 12 used in one example of the bubble concentration adjustment device 10 according to Modified Example 4.
  • the operation unit 42 of the flow rate ratio control unit 12 is configured to perform an operation for changing the flow rate ratio.
  • the operation unit 42 may be formed integrally with the flow rate control member 16 or may be formed separately therefrom.
  • the operation unit 42 is provided with a knob 42A.
  • the knob 42A is rotatably mounted, and when the rotation position of the knob 42A is changed by rotating it, the flow rate ratio control unit 12 changes the flow rate ratio between the liquid flowing through the first flow path and the liquid flowing through the second flow path so that the flow rate ratio corresponds to the value of the scale 41 (i.e., the value indicated at the outer position along the longitudinal direction of the knob 42A) determined in accordance with the rotation position.
  • FIG. 5A shows the values of the scale 41 as numerals from 1 to 5, but this is merely an example.
  • the rotation direction of the knob 42A is indicated by an arrow RT.
  • the scale display unit 40 is provided with indicia (such as numbers or marks that are visually identifiable) as the scale 41, which indicate information corresponding to the bubble concentration of the entire liquid (gas-liquid mixture) flowing out of the outlet.
  • the flow rate ratio can be associated in advance with the bubble concentration.
  • bubble concentration here refers to the bubble concentration in a mixed liquid that is defined on the assumption that the liquids having passed through the plurality of flow paths 11 are mixed.
  • the flow rate ratio can be associated in advance with the bubble concentration according to the pressure, flow velocity, and flow rate of the liquid flowing into the flow paths 11. Also, the flow rate ratio can be associated with the state of the flow rate control member 16.
  • the scale display unit 40 indicates, as the value of the scale 41, the bubble concentration determined from the state of the flow rate control member 16, corresponding to each state of the flow rate control member 16.
  • the flow rate ratio control unit 12 changes the flow rate ratio according to the bubble concentration (the value shown on the scale 41) displayed on the scale display unit 40. Therefore, once the value of the scale 41 is determined, the target bubble concentration is specified, and the flow rate ratio according to the pressure, flow velocity, and flow rate of the liquid flowing into the flow paths 11 is also determined, and the state of the flow rate control member 16 is controlled so as to approximately realize the flow rate ratio.
  • the flow rate ratio control unit 12 changes the flow rate ratio in accordance with the scale 41 of the scale display unit 40.
  • the scale display unit 40 may include, as the scale 41, either an evenly spaced scale or a logarithmic scale.
  • the scale 41 is configured as a fixed design; however, the scale 41 in the scale display unit 40 may alternatively be configured as a digital display. It is sufficient that the scale 41 of the flow rate ratio control unit 12 corresponds to the concentration of fine bubbles ultimately contained in the entirety of the liquid flowing out of the outlet.
  • the correspondence between the bubble concentration NT of the mixed liquid and WA:WB is predetermined. Also, since the rotation position of the knob corresponds to WA:WB, the rotation position of the knob can be associated with the bubble concentration NT.
  • the value of the scale 41 is provided at a predetermined position so that the rotation position of the knob 42A and the bubble concentration NT can be visually recognized. For example, in FIG. 5A , the scale 41 indicates "2", and the flow control member 16 changes the flow rates of the liquid flowing through the first flow path 11A and the second flow path 11B as necessary so that WA:WB realizes a bubble concentration NT corresponding to the value "2".
  • the bubble concentration NT is not limited to being associated with the rotation position of the knob 42A.
  • the knob 42A may be omitted, and the operation unit 42 of the flow rate ratio control unit 12 may be provided with an input unit 44 for bubble concentration as a concentration display unit instead of the scale display unit 40.
  • the operation unit 42 has previously stored data regarding the correspondence between the flow rate ratio and the bubble concentration in accordance with the pressure, flow velocity, and flow rate of the liquid flowing into the flow path 11.
  • the operation unit 42 determines the flow rate ratio based on the input bubble concentration value and in accordance with conditions such as the pressure, flow velocity, and flow rate of the liquid, and controls the state of the flow rate control member 16 so that the determined flow rate ratio is achieved.
  • a computer which stores a database such as a correspondence table indicating the relationship between various conditions related to the liquid flowing into the flow path 11-such as pressure, flow velocity, flow rate, and flow rate ratio-and the concentration of fine bubbles (bubble concentration) in the entire liquid flowing out from the outlet.
  • the input unit 44 is connected to the computer. Based on the fine bubble concentration value (bubble concentration value) input via the input unit 44, the computer refers to the database such as a correspondence table showing the relationship between the aforementioned conditions of the liquid flowing into the flow path 11 and the fine bubble concentration, and the state of the distribution valve 21 (i.e., the state of the flow rate control member 16) may be controlled accordingly.
  • the operation unit 42 includes a display unit 43 that displays the value input via the input unit 44.
  • the operator can perform operations for obtaining a liquid having a desired bubble concentration while visually recognizing the operation procedure, thereby suppressing the risk that a liquid with an unintended bubble concentration is erroneously generated.
  • the flow rate ratio control unit 12 may further include a status checking unit 30. This is referred to as Modified Example 5.
  • Fig. 4B is a schematic diagram illustrating an example of the bubble concentration adjustment device 10F according to Modified Example 5.
  • the status checking unit 30 is configured to check whether the states of the plurality of flow paths 11 are in a condition capable of achieving the bubble concentration (i.e., the bubble concentration of the mixed liquid) set by the operation unit 42.
  • the status checking unit 30 includes a flow rate sensor (first flow rate sensor 31A) for measuring the flow rate of the liquid flowing through the first flow path 11A, and a flow rate sensor (second flow rate sensor 31B) for measuring the flow rate of the liquid flowing through the second flow path 11B.
  • the bubble concentration (bubble concentration based on actual measurement) of the entire liquid (mixed liquid) flowing out from the outlet is determined based on the measurement values of the first flow rate sensor 31A and the second flow rate sensor 31B.
  • a measurement result display unit 33 may be provided.
  • the measurement result display unit 33 displays information for recognizing the presence or absence of a difference between the bubble concentration based on the actual measurement and the bubble concentration determined by the operation unit 42 (e.g., numerical data indicating the difference between the measured bubble concentration and the value determined by the operation unit 42).
  • the first flow rate sensor 31A, the second flow rate sensor 31B, the measurement result display unit 33, and the operation unit 42 are electrically connected via wiring or the like to allow signal transmission.
  • these components may be wirelessly connected so that signals can be transmitted. This also applies to FIGS. 4C , 7 , 9 , and 10 .
  • FIG. 4C is a schematic diagram illustrating an example of the bubble concentration adjustment device 10G according to Modified Example 6.
  • the sensor 34 is not particularly limited as long as it detects at least one of the pressure, flow velocity, and flow rate of the liquid flowing through the bubble generating unit 13. By comparing the expected condition of the liquid flowing through the bubble generating unit 13 under the assumption that the bubble generating unit 13 is operating normally, with the condition of the liquid based on the values measured by the sensor 34, it is possible to confirm whether the bubble generating unit 13 is in normal operation.
  • the tank system 200 includes, as shown in FIG. 6 , a tank 210 as a tank body for storing a liquid (storage liquid GL), and a bubble concentration adjustment device 220.
  • the bubble concentration adjustment device 220 includes a plurality of flow paths 270 (a first flow path 270A and a second flow path 270B), a flow rate control member 290, a flow rate ratio control unit 295, an inlet 260, an outlet 250, and a bubble generating unit 280.
  • the bubble concentration adjustment device 220 can apply the bubble concentration adjustment device 10 described in "1. Bubble Concentration Adjustment Device," including its modified examples.
  • FIG. 6 is a schematic diagram illustrating a configuration of an example of the tank system according to the first embodiment. The example shown in FIG. 6 illustrates a case in which the bubble concentration adjustment device 10 shown in FIG. 1 is applied as the bubble concentration adjustment device 220.
  • the tank 210 is not particularly limited as long as it has a space 230 in which a liquid (storage liquid GL) can be stored therein.
  • the tank 210 has a structure in which the upper surface serves as an opening 240, although this is merely an example.
  • examples that can be used include a water storage tank installed in various types of buildings such as office buildings and apartment complexes, a facility such as a swimming pool, a bathtub provided in a bathroom or public bathhouse, a tank that stores a coolant for a cooling device, a storage tank connected to various devices and used to store liquid to be supplied to such devices, a storage unit mounted in a cleaning device, a fuel storage tank capable of storing reserve fuel or the like, a water tank for aquaculture of fish and the like, and a tank used for nutrient solution cultivation.
  • the configuration in which the tank 210 and the bubble concentration adjustment device 220 are arranged is not particularly limited as long as the liquid is supplied to the tank 210 after passing through the bubble concentration adjustment device 220.
  • the outlet 250 of the bubble concentration adjustment device 220 is located below the opening on the upper surface of the tank 210 (i.e., within the space 230), but this is merely an example. It suffices that the liquid having generated bubbles (fine bubbles and ultrafine bubbles) by passing through the first flow path 270A of the bubble concentration adjustment device 220 and the liquid that has passed through the second flow path 270B are supplied to the tank 210.
  • a storage liquid discharge unit 300 may be provided.
  • the storage liquid discharge unit 300 is not particularly limited as long as it has a structure for discharging the liquid (storage liquid GL) stored in the tank 210 to the outside.
  • the storage liquid discharge unit 300 includes a discharge flow path 310 for delivering the storage liquid to the outside. Additionally, a pump 320 for delivering the storage liquid GL into the discharge flow path 310 may be provided as needed.
  • the discharge flow path 310 may be formed using piping or the like made of the same material as the pipe member 20 that constitutes the flow paths 11, for example.
  • the bubble concentration adjustment device 220 described above since the bubble concentration adjustment device 220 described above is provided, the gas-liquid mixture with an adjusted bubble concentration flowing out from the flow outlet 250 can flow into the tank, and the gas-liquid mixture can be stored in the tank 210. Therefore, in the tank system 200 according to the first embodiment, it is possible to use, as the stored liquid GL in the tank 210, a liquid (gas-liquid mixture) having a bubble concentration adjusted according to the user's requirements.
  • FIG. 7 is a schematic diagram illustrating a configuration of an example of the tank system 200A according to Modified Example 1 of the first embodiment.
  • the inflow amount control structure 330 includes a concentration sensor 331 for measuring the bubble concentration in the stored liquid in the tank.
  • concentration sensor 331 include sensors that employ laser diffraction/scattering methods.
  • concentration sensor a sensor device using green laser light can be used.
  • reference numeral 332 denotes wiring. The wiring 332 in FIG. 7 transmits signals for controlling the state of the flow rate control member 290.
  • the bubble concentration in the tank 210 is measured by the concentration sensor 331.
  • the flow rate ratio control unit 295 is controlled by adjusting the flow rate control member 290 so that the bubble concentration of the overall liquid (i.e., the mixed liquid obtained by combining the liquids that have passed through each of the plurality of flow paths) flowing from the outlet 250 of the bubble concentration adjustment device 220 into the tank 210 reaches a predetermined concentration.
  • the state of the flow rate control member 290 is controlled as needed to introduce a gas-liquid mixture with a bubble concentration M3, which has passed through the first flow path 270A of the bubble concentration adjustment device 220, into the tank.
  • the bubble concentration M3 is set to be higher than the bubble concentration M2.
  • the state of the flow rate control member 16 is controlled as needed to introduce into the tank the liquid that has flowed through the second flow path 270B of the bubble concentration adjustment device 220 (the bubble concentration of which is lower than M4 or zero). Then, when the bubble concentration in the tank 210 decreases to M4, the pouring of the gas-liquid mixture from the bubble concentration adjustment device 220 into the tank 210 is stopped.
  • the bubble diameter is extremely small, for example, less than 1 ⁇ m, such bubbles are considered to be capable of remaining in the liquid for a certain period of time. Therefore, according to the tank system 200 of Modified Example 1 of the first embodiment, when it is necessary to change the bubble concentration of the liquid (stored liquid GL) that has flowed into the tank 210 from the outlet 250, it is possible to re-adjust the bubble concentration by adding another liquid having a different bubble concentration into the tank 210.
  • the tank system 200 of Modified Example 1 of the first embodiment by using in combination the position sensor described in Modified Example 2 of the first embodiment, which will be described later, it is also possible to adjust the amount of storage liquid in the tank 210 to a desired amount while setting the bubble concentration to a desired value.
  • the tank system 200A may be configured such that the amount of liquid in the tank 210 is detected and liquid is replenished from the bubble concentration adjustment device 220 in accordance with the amount of liquid in the tank 210 (not shown).
  • This is referred to as Modified Example 2 of the first embodiment.
  • Modified Example 2 of the first embodiment may be configured similarly to Modified Example 1 of the first embodiment, except that a position sensor for detecting the liquid level is used in the tank 210 instead of the concentration sensor 331. According to Modified Example 2 of the first embodiment, a state in which a fixed amount of gas-liquid mixture with an adjusted bubble concentration is stored in the tank 210 can be maintained.
  • a tank system 200 according to the second embodiment includes, as shown in FIG. 8 , a tank (referred to as tank 210A in FIG. 8 ) for storing a liquid, and a bubble concentration adjustment device 220.
  • the bubble concentration adjustment device 220 can apply the bubble concentration adjustment device 10 described in the above section "1. Bubble Concentration Adjustment Device" (including all the modifications except for Modified Example 1 shown in FIG. 3A ). Accordingly, detailed explanation of the configuration of the bubble concentration adjustment device 220 is omitted.
  • FIG. 8 is a schematic diagram illustrating a configuration of an example of the tank system according to the second embodiment. In the example of FIG. 8 , the bubble concentration adjustment device 10 shown in FIG. 1 is applied as the bubble concentration adjustment device 220.
  • the tank 210A has a space 230 for storing a liquid therein, and the internal space 230 is partitioned into multiple sections, forming a plurality of spatial portions.
  • the internal space of the tank is partitioned into a first spatial portion 231A and a second spatial portion 231B.
  • the tank 210A has an open-top structure, although this is merely one example.
  • examples that can be used for the tank 210A include a water storage tank installed in various types of buildings such as office buildings and apartment complexes, a tank that stores a coolant for a cooling device, a storage tank connected to various devices and used to store liquid to be supplied to such devices, a storage unit mounted in a cleaning device, a fuel storage tank capable of storing reserve fuel or the like, a water tank for aquaculture of fish and the like, and a tank used for nutrient solution cultivation.
  • the tank 210A and the bubble concentration adjustment device 220 may be arranged such that the liquid, after passing through the bubble concentration adjustment device 220, is supplied from the respective outlets 250 to the respective space portions of the tank 210A (i.e., the first space portion 231A and the second space portion 231B), and the structure for arranging the tank 210A and the bubble concentration adjustment device 220 is not particularly limited.
  • the outlet 250 of the first flow path 270A is located directly above the first space portion 231A
  • the outlet 250 of the second flow path 270B is located directly above the second space portion 231B; however, this is merely an example.
  • a storage liquid discharge unit 300 (referred to as storage liquid discharge unit 300A in FIG. 8 ) may be provided.
  • the storage liquid discharge unit 300A is not particularly limited as long as it has a structure capable of discharging the storage liquid stored in the respective space portions (the first space portion 231A and the second space portion 231B) of the tank 210A to the outside.
  • the storage liquid discharge unit 300A includes a discharge flow path 310 that delivers the storage liquid stored in the tank 210A to the outside.
  • the discharge flow path 310 can be formed using piping or the like made of a material similar to that of the pipe member 20 constituting the flow path 11, for example. In the example shown in FIG.
  • the discharge flow path 310 includes a first discharge flow path 310A for discharging the storage liquid stored in the first space portion 231A and a second discharge flow path 310B for discharging the storage liquid stored in the second space portion 231B.
  • the first discharge flow path 310A and the second discharge flow path 310B are connected at a predetermined position and extend to the outside of the tank 210A.
  • a portion of the discharge flow path 310 that extends outward from the point where the first and second discharge flow paths 310A and 310B are joined is referred to as a mixed storage liquid discharge path 310C.
  • the mixed storage liquid discharge path 310C allows the mixed liquid of the storage liquids from the first and second space portions 231A and 231B to flow therethrough.
  • a pump 320 for delivering the storage liquid into the discharge flow path 310 is provided in the mixed storage liquid discharge path 310C.
  • a control valve 321 may be provided in the first discharge flow path 310A, the control valve 321 being configured to allow adjustment of the amount of storage liquid flowing through the first discharge flow path 310A.
  • the above-described bubble concentration adjustment device 220A is provided, and the liquid that has flowed out from each of the outlets 250 can be stored in each of the space portions of the tank 210A.
  • the liquid e.g., gas-liquid mixture
  • the tank system 200B according to the second embodiment it becomes possible to flow out of the tank 210A a liquid (gas-liquid mixture) adjusted to various bubble concentrations in accordance with the user's requirements.
  • a tank system 200 according to a third embodiment includes, as shown in FIG. 9 , a tank 210B for storing a liquid, a flow path 340 for causing the liquid to flow, and a bubble generating unit 341.
  • the tank 210B usable in the third embodiment is the same as the tank 210B described in the first embodiment, and therefore, detailed explanation is omitted.
  • the bubble generating unit 341 is a device capable of generating bubbles having a diameter of less than 1 ⁇ m in the liquid (storage liquid) in the tank 210B. Since the same type of bubble generating unit as the bubble generating unit 13 provided in the bubble concentration adjustment device 10 described above in section "1. Bubble Concentration Adjustment Device" can be applied to the bubble generating unit 341, detailed explanation is also omitted.
  • FIG. 9 is a schematic diagram illustrating a configuration of an example of the tank system 200C according to the third embodiment.
  • the flow path 340 is connected at both its upstream end PA and downstream end PB to the space 230 inside the tank 210B, and the liquid (storage liquid GL) in the tank 210B can flow through the flow path 340 in the direction of arrow FS and circulate between the tank 210B and the flow path 340.
  • a bubble generating unit 341 is provided in the flow path 340, and when the liquid flowing into the flow path 340 from the upstream end PA passes through the bubble generating unit 341, bubbles are generated in the liquid.
  • the flow path 340 can be formed using piping or the like made of the same material as the pipe member 20 constituting the flow path 11.
  • a storage liquid discharge unit 300 may be provided.
  • the storage liquid discharge unit 300 may have the same structure as that described in the first embodiment and the like, and therefore, detailed explanation is omitted.
  • a circulation flow rate control valve 342 which is configured to allow adjustment of the flow rate of the liquid (storage liquid GL) flowing through the flow path 340, may be provided.
  • the circulation flow rate control valve 342 may employ the same structure as the control valve 22 described in Modified Example 3 of the bubble concentration adjustment device 10.
  • a timer 343 is also provided to set the time duration during which the circulation flow rate control valve 342 maintains a state that allows liquid to flow through the interior of the flow path 340.
  • the timer 343 is preferably a timer switch that controls the state of the circulation flow rate control valve 342 upon the elapse of the set time.
  • the circulation flow rate control valve 342 has a function for opening and closing the flow path 340. In this case, the tank system 200C becomes capable of controlling the open state of the flow path 11 so that liquid flows through the interior of the flow path 11 only for the time period defined by the timer 343.
  • the timer 343 can be set to a time corresponding to a desired fine bubble concentration or ultrafine bubble concentration.
  • the time defined by the timer 343 can be set to the time required for the bubble concentration (particularly, the fine bubble concentration or ultrafine bubble concentration) of the storage liquid GL to reach the desired value, a gas-liquid mixture having bubbles (particularly, fine bubbles or ultrafine bubbles) at the desired concentration can be obtained as the storage liquid GL.
  • the storage liquid GL in the tank 210B flows from the upstream end PA of the flow path 340 into the flow path 340, passes through the bubble generating unit 341, and is then returned to the tank 210B from the downstream end PB of the flow path 340. Therefore, according to the third embodiment, the storage liquid GL in the tank 210B can be made into a liquid containing bubbles generated by the bubble generating unit 341. Further, by circulating the storage liquid GL through the flow path 340, the bubble concentration of the storage liquid GL can be increased in accordance with the operating time of the bubble generating unit 341.
  • the tank system 200 according to the third embodiment may include a liquid inflow unit 350, as shown in FIG. 10 .
  • This configuration is referred to as a modified example of the third embodiment.
  • FIG. 10 is a schematic diagram illustrating a configuration of an example of the tank system 200D according to the modified example of the third embodiment.
  • the liquid inflow unit 350 is not particularly limited as long as it has a structure capable of pouring liquid from an external liquid supply source (not shown) into the tank 210B.
  • the liquid inflow unit 350 includes an inflow flow path 351 that delivers liquid to the tank 210B. Additionally, as needed, an inflow amount control valve 353, which performs opening and closing of the inflow flow path 351, and a pump (not shown) that feeds liquid into the inflow flow path 351 from the external liquid supply source may be provided.
  • the inflow amount control valve 353 may have the same structure as the control valve 22 described in Modified Example 3 of the bubble concentration adjustment device 10.
  • the tank system 200D according to the modified example of the third embodiment has the same structure as the tank system 200C according to the third embodiment. Therefore, a detailed description of the other components of the tank system 200D according to the modified example of the third embodiment, except for the configuration of the liquid inflow unit 350 and the configurations of the inflow flow rate sensor 352 and the timer 343A described later, will be omitted.
  • an inflow flow rate sensor 352 which detects the flow rate (inflow amount) of the liquid flowing into the tank 210, is provided, as shown in FIG. 10 .
  • the inflow flow rate sensor 352 may be of the same type as the first flow rate sensor 31A or the second flow rate sensor 31B shown in Modified Example 5 described in [1. Bubble Concentration Adjustment Device] above.
  • the timer 343 (referred to as timer 343A in FIG. 10 ) defines a time T1 for maintaining the state of the circulation flow rate control valve 342 and a time T2 for maintaining the state of the inflow control valve 353.
  • the times T1 and T2 are determined based on the measurement value of the inflow flow rate sensor 352, the amount of storage liquid GL passing through the bubble generating unit 341, the desired bubble concentration (target concentration of the storage liquid GL), and the desired amount of storage liquid GL (target volume of the storage liquid GL). For example, the difference between the current amount of storage liquid GL and its target volume, and the difference between the current bubble concentration and the target concentration of the storage liquid GL are determined.
  • the operating time of the bubble generating unit 341 can be specified as time T1
  • the time for introducing liquid into the tank 210 from the liquid inflow unit 350 can be specified as time T2.
  • the timer 343A is a timer switch configured to change the state of the circulation flow rate control valve 342 to close the flow path 340 upon the lapse of the set time T1, and also to change the state of the inflow control valve 353 to close the inflow flow path 351 upon the elapse of the set time T2.
  • the tank system 200D of the modified example of the third embodiment even if the bubble concentration of the storage liquid GL into the tank 210 fluctuates due to the inflow of liquid into the tank 210, it becomes possible to operate the bubble generating unit 341 until the bubble concentration of the storage liquid GL rises to a predetermined value, thereby facilitating adjustment of the bubble concentration of the storage liquid GL.

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Abstract

A bubble concentration adjustment device and a tank system that allow adjustment of a bubble concentration in a bubble-containing liquid are provided. The bubble concentration adjustment device includes a plurality of flow paths for transporting a liquid, at least one of which is provided with a bubble generating unit capable of generating bubbles having a diameter of less than 1 µm in the liquid. The device further includes a flow rate ratio control unit for changing a flow rate ratio of the liquid flowing through the plurality of flow paths so that the bubble concentration can be adjusted by mixing the liquid flowing out of the plurality of flow paths.

Description

    TECHNICAL FIELD
  • The present invention relates to a bubble concentration adjustment device and a tank system.
    • BACKGROUND ART
  • There is a demand in various industrial fields for the use of bubble generating devices that generate a gas-liquid mixture containing bubbles having a diameter of 1 µm or less in a liquid.
    Patent Document 1 discloses a proposal in which a bubble generating device is provided in a tank installed in the circulation system of an air-conditioning system, and contaminants in the circulation system are removed using the gas-liquid mixture stored in the tank.
    • PRIOR ART DOCUMENT PATENT DOCUMENT
  • Patent Document 1: JP 2008-190754 A
    • SUMMARY OF INVENTION PROBLEM TO BE SOLVED BY THE INVENTION
  • In the technique proposed in Patent Document 1, there is room for improvement from the viewpoint of adjusting the bubble concentration contained in the bubble-containing liquid stored in the tank.
  • An object of the present invention is to provide a bubble concentration adjustment device and a tank system that make it possible to adjust a bubble concentration contained in a bubble-containing liquid.
    • MEANS FOR SOLVING THE PROBLEM
  • The present invention is characterized by the following items (1) to (6).
    1. (1) A bubble concentration adjustment device including:
      • a plurality of flow paths for transporting a liquid;
      • a bubble generating unit provided in at least one of the flow paths, the bubble generating unit being capable of generating bubbles having a diameter of less than 1 µm in the liquid; and
      • a flow rate ratio control unit for changing a flow rate ratio of the liquid flowing through the plurality of flow paths so as to enable adjusting the concentration of the bubbles by mixing the liquid flowing out of the plurality of flow paths.
    2. (2) The bubble concentration adjustment device according to item (1), further including a scale display unit for indicating a concentration of the bubbles,
      wherein the flow rate ratio control unit changes the flow rate ratio in accordance with the concentration of the bubbles indicated on the scale display unit.
    3. (3) The bubble concentration adjustment device according to item (2), further including an inlet for receiving the liquid,
      wherein the flow rate ratio control unit changes the flow rate ratio in accordance with at least one of a pressure, a flow velocity, and a flow rate of the liquid received from the inlet.
    4. (4) The bubble concentration adjustment device according to item (3), wherein the inlet is common to the plurality of flow paths, and
      the flow rate ratio control unit changes the flow rate ratio by changing a distribution ratio of the liquid supplied from the inlet to each of the plurality of flow paths.
    5. (5) A tank system including:
      • the bubble concentration adjustment device according to item (1); and
      • a tank for storing the liquid,
      • wherein the bubble concentration adjustment device and the tank are arranged so that the liquid is supplied to the tank after passing through the bubble concentration adjustment device.
    6. (6) A tank system including:
      • a tank for storing a liquid; and
      • a flow path for transporting the liquid,
      • wherein the flow path includes a bubble generating unit for generating bubbles having a diameter of less than 1 µm in the liquid,
      • both an upstream end and a downstream end of the flow path are connected to the tank, and
      • a timer is provided for determining a time during which the liquid flows through the flow path.
    EFFECT OF THE INVENTION
  • According to the present invention, it is possible to provide a bubble concentration adjustment device and a tank system that allow adjustment of the amount of bubbles contained in a gas-liquid mixture.
    • BRIEF DESCRIPTION OF DRAWINGS
    • FIG. 1 is a schematic diagram illustrating a configuration of an example of a bubble concentration adjustment device according to the present invention.
    • FIG. 2A is a cross-sectional view illustrating a configuration of an embodiment of a bubble generating device.
    • FIG. 2B is a diagram showing a state of an example of a bubble generation mechanism of the bubble generating device when viewed in the direction from the upstream end to the downstream end.
    • FIG. 2C is a schematic cross-sectional view corresponding to the longitudinal sectional line A-A in FIG. 2A with respect to the bubble generating device.
    • FIG. 2D is a schematic enlarged cross-sectional view showing an enlarged state of a portion of the region SP enclosed by a dashed line in FIG. 2C.
    • FIGS. 3A to 3D are schematic diagrams illustrating a configuration of an example of a bubble concentration adjustment device according to the present invention.
    • FIGS. 4A to 4C are schematic diagrams illustrating a configuration of an example of a bubble concentration adjustment device according to the present invention.
    • FIGS. 5A and 5B are diagrams illustrating an example of an operation unit.
    • FIG. 6 is a schematic diagram illustrating a configuration of an example of a tank system according to the first embodiment.
    • FIG. 7 is a schematic diagram illustrating a configuration of an example of a tank system according to Modified Example 1 of the first embodiment.
    • FIG. 8 is a schematic diagram illustrating a configuration of an example of a tank system according to the second embodiment.
    • FIG. 9 is a schematic diagram illustrating a configuration of an example of a tank system according to the third embodiment.
    • FIG. 10 is a schematic diagram illustrating a configuration of an example of a tank system according to a modified example of the third embodiment.
    DESCRIPTION OF EMBODIMENTS
  • An embodiment of the present invention will be described in the order of "1. Bubble Concentration Adjustment Device" and "2. Tank System." In "2. Tank System," the explanation will be provided in the order of the first embodiment, the second embodiment, and the third embodiment.
  • It should be noted that the present invention is not limited to the embodiments described below.
    • [1. Bubble Concentration Adjustment Device]
  • The bubble concentration adjustment device according to the present invention has a structure for controlling the amount of bubbles (bubble concentration) contained in a liquid having bubbles.
    • [Configuration]
  • As shown in FIG. 1, a bubble concentration adjustment device 10 includes a plurality of flow paths 11, a flow rate ratio control unit 12, and a bubble generating unit 13.
    • (Flow Paths)
  • The flow paths 11 are configured so as to allow liquid to flow therethrough, and specifically, they can be exemplified by a structure formed with pipe members 20. The sizes of the plurality of flow paths 11 (i.e., the size of the longitudinal cross section of each flow path 11, taken in a plane perpendicular to the longitudinal direction of the flow path 11) may be the same or may differ among some of the flow paths. The number of the flow paths 11 is not particularly limited, and may be two or three or more. In the example shown in FIG. 1, two flow paths 11 are provided, and when these two flow paths 11 are referred to as a first flow path 11A and a second flow path 11B, both are composed of pipe members 20 having the same longitudinal cross-sectional size. That is, the example in FIG. 1 illustrates a case in which the plurality of flow paths 11 have the same longitudinal cross-sectional size. With reference to FIG. 1, the description of the bubble concentration adjustment device 10 will be continued. In FIG. 1, an arrow F indicates a flow of liquid flowing in from an inlet 14, which will be described later; an arrow FP1 indicates a flow of liquid through the first flow path 11A; and an arrow FP2 indicates a flow of liquid through the second flow path 11B. These apply similarly to FIGS. 3A to 3D, FIGS. 4A to 4C, and FIGS. 6 to 8. (In FIGS. 6 to 8, the arrows FP1 and FP2 indicate flows of liquid through a first flow path 270A and a second flow path 270B, respectively.)
    • (Inlet)
  • In the bubble concentration adjustment device 10, an inlet 14 for receiving liquid is formed, as shown in the example of FIG. 1, and liquid from an external liquid supply source (not shown) can be introduced through the inlet 14. The liquid poured in the direction of arrow F from the inlet 14 can flow from the upstream end to the downstream end through any of the flow paths 11. Although the inlet 14 may be formed individually for each of the plurality of flow paths 11, the inlet 14 is preferably common to the plurality of flow paths 11. The expression that the inlet 14 is common means that the liquid flowing through any of the plurality of flow paths 11 is supplied from the same inlet 14. When the inlet is common to the plurality of flow paths 11, the inlet is specified as a single inlet, as shown in FIG. 1. If there is a single inlet, it becomes easier to adjust the bubble concentration of the liquid (i.e., the mixed liquid determined assuming the overall liquid flowing out from the outlet) obtained via the bubble concentration adjustment device 10 by controlling the flow of liquid introduced through the single inlet.
  • In the bubble concentration adjustment device 10, it is preferable that the liquid stably flows from an external liquid supply source into the flow paths 11 through the inlet 14 while satisfying a predetermined range of pressure, flow velocity, and flow rate. From the viewpoint of achieving this more reliably, when using the bubble concentration adjustment device 10, it is preferable to adopt, as a structure (hereinafter referred to as a flow-in assistance structure) for causing the liquid to flow from the inlet 14 toward the flow paths 11, a structure in which a device such as a pump is disposed outside the inlet 14, or a structure in which the supply source is located at a position higher than a predetermined level above the inlet 14.
  • The presence of a flow-in assistance structure when using the bubble concentration adjustment device 10 can exhibit particularly high effectiveness in the case where the bubble generating unit 13, which will be described later, is a cavitation-type device (bubble generating device). This is because, when the bubble generating unit is a cavitation-type device, the bubble generating device can more reliably generate bubbles in the liquid-such as fine bubbles (including ultrafine bubbles and microbubbles), which will be described later-if the liquid supplied to the bubble generating device has a pressure, flow velocity, and flow rate that satisfy a predetermined range.
    • (Receiving Flow Path)
  • In the example shown in FIG. 1, the bubble concentration adjustment device 10 includes a receiving flow path 15 that is formed with an inlet 14 at its upstream end and is configured to receive the liquid flowing in through the inlet 14. The downstream end of the receiving flow path 15 (i.e., the end opposite to the inlet 14 along the direction of arrow F) is connected to the upstream ends of the first flow path 11A and the second flow path 11B. However, in the example of FIG. 1, the first flow path 11A and the second flow path 11B are connected to the receiving flow path 15 via a flow rate control member 16, which will be described later. That is, in the example of FIG. 1, the bubble concentration adjustment device 10 is configured such that the receiving flow path 15 is connected at its downstream end to the flow rate control member 16, and the flow rate control member 16 branches into the first flow path 11A and the second flow path 11B. Thus, the liquid flowing through either the first flow path 11A or the second flow path 11B flows in from the common inlet 14. Note that the arrangement of the receiving flow path 15 and the plurality of flow paths 11 shown in FIG. 1 is merely an example and is not limited thereto. As will be described later, the receiving flow path 15 may be integrated with either the first flow path 11A or the second flow path 11B. In such a case, as also described in Modified Example 3 below, a part of the first flow path 11A or a part of the second flow path 11B serves also as the receiving flow path 15, forming a structure in which the second flow path 11B branches from the first flow path 11A, or conversely, the first flow path 11A branches from the second flow path 11B.
  • The receiving flow path 15 may be provided with the above-described flow-in assistance structure. For example, a pump or the like may be provided in the middle of the receiving flow path 15. By providing a pump or the like in the middle of the receiving flow path 15, it becomes easier to stabilize the pressure, flow velocity, and flow rate of the liquid flowing through the receiving flow path 15 within a predetermined range.
    • (Liquid)
  • The liquid flowing through the flow paths 11 is not particularly limited, and examples thereof include a solvent, or a substance in which a compound or the like is dissolved, dispersed, or mixed in the solvent (e.g., a solution, dispersion, or mixture). Examples of the solvent include water and organic solvents. Examples of water include tap water, well water, seawater, purified water, ultrapure water, and water that has undergone a supercritical state (supercritical-state-passed water).
    Examples of organic solvents include alcohols and oils. Examples of compounds or the like that can be dissolved in the solvent include inorganic compounds such as covalent substances like carbon dioxide, nitrogen, and oxygen; inorganic electrolytes such as sodium chloride; and various organic compounds such as aliphatic hydrocarbons, aromatic hydrocarbons, alcohols, peptides, and fatty acids.
  • The liquid flowing through the flow paths 11 may be determined according to the intended use of a gas-liquid mixture containing fine bubbles or ultrafine bubbles as bubbles. The intended use of the gas-liquid mixture may be determined in accordance with the effects thereof. The effects of incorporating fine bubbles or ultrafine bubbles as bubbles into a liquid include effects related to solubility, separability, washability, fluidity, and improvement in the quality of medical treatment and diagnostics. Effects related to solubility due to bubbles include: improvement in the effectiveness of ozonated water; enhanced miscibility of oil and additives; promotion of emulsification of oil and water; oxygen enrichment of liquid fertilizers by containing oxygen-containing bubbles; and improvement of water quality for fish farming. Effects related to separability due to bubbles include soil purification and water purification. Effects related to washability include improved cleaning performance of precision instruments, home appliances, food materials, and human bodies, as well as enhanced cleaning performance in cleaning processes in production lines. An effect related to efficiency improvement due to bubbles includes conversion into fuel by promoting emulsification of oil (e.g., waste oil) and water using bubbles. Effects related to the improvement in the quality of medical treatment and diagnostics include enhancement of the effectiveness of ultrasonic therapy through the combined use of ultrasound and bubbles. The bubble concentration adjustment device 10 is applicable to cases where a gas-liquid mixture is generated in order to achieve various effects produced by bubbles. The liquid flowing through the bubble concentration adjustment device 10 includes liquids used to generate such a gas-liquid mixture for achieving the various effects produced by the bubbles. Examples of the liquid flowing through the flow paths 11 include: liquids used in food products such as juices and sugar water; cleaning solutions used in hospitals and the like; medical liquids such as physiological saline; and various liquid fuels such as gasoline, diesel fuel, kerosene, and jet fuel.
    • (Flow Rate Ratio Control Unit)
  • The flow rate ratio control unit 12 provided in the bubble concentration adjustment device 10 includes a flow rate control member 16. In FIG. 1, the flow rate ratio control unit 12 is indicated by a dashed line for convenience of explanation. This also applies to FIGS. 3 and 4, and the like.
  • The flow rate ratio control unit 12 is a component for adjusting the flow rate of the liquid flowing through the flow paths 11. That is, the flow rate ratio control unit 12 may also be referred to as a flow rate ratio variable section. The flow rate ratio control unit 12 is capable of changing a flow rate ratio of the liquid flowing through the plurality of flow paths 11 so as to allow adjustment of the concentration (bubble concentration) of bubbles by mixing the liquid flowing out of the plurality of flow paths 11. In this context, the flow rate (cm3/sec) of the liquid flowing through each flow path 11 refers to the volume (cm3) of liquid flowing into the flow path per unit time (sec). In the example shown in FIG. 1, the flow rate ratio is given as the ratio of the amount (flow rate) of liquid flowing through the first flow path to the amount (flow rate) of liquid flowing through the second flow path from among the liquid introduced through the inlet. The flow rate ratio is defined as WA:WB, where WA is the amount (flow rate) of the liquid flowing through the first flow path, and WB is the amount (flow rate) of the liquid flowing through the second flow path. In particular, according to the bubble concentration adjustment device 10, the flow rate ratio control unit 12 controls (changes) the flow rate ratio so as to allow adjustment of the concentration of fine bubbles (sometimes referred to as "fine bubble concentration") or the concentration of ultrafine bubbles (sometimes referred to as "ultrafine bubble concentration"), which will be described later.
  • The flow rate ratio control unit 12 is configured to be capable of changing the flow rate ratio in accordance with the bubble concentration of the entire liquid discharged per unit time from the outlet. The flow rate ratio control unit 12 is not particularly limited as long as it has a structure capable of changing and controlling the flow rate of the liquid flowing through each of the flow paths 11. In the example shown in FIG. 1, it corresponds to a portion having a distribution valve 21. In the example of FIG. 1, the "entire liquid discharged per unit time" refers to the combined liquid consisting of the liquid discharged per unit time from the outlet of the first flow path 11A and the liquid discharged per unit time from the outlet of the second flow path 11B.
    • (Flow Rate Control Member)
  • The flow rate control member 16 is a member capable of controlling the flow of liquid through the flow path 11. In the example shown in FIG. 1, the flow rate control member 16 is the distribution valve 21.
    • (Distribution Valve)
  • The distribution valve 21 shown in the example of FIG. 1 is provided at a position connected to the downstream end of the receiving flow path 15 and to the upstream ends of the first flow path 11A and the second flow path 11B. The distribution valve 21 controls a distribution ratio of the liquid supplied from the inlet 14 to each of the plurality of flow paths 11. In the example of FIG. 1, the structure of the distribution valve 21 is not particularly limited as long as it has a structure capable of changing the ratio of the amount of liquid flowing into the first flow path 11A to the amount of liquid flowing into the second flow path 11B (i.e., a structure capable of changing the distribution ratio). The distribution valve 21 is configured so as to be capable of changing the ratio of the amount (flow rate WA) of liquid flowing into the first flow path and the amount (flow rate WB) of liquid flowing into the second flow path with respect to the total flow rate (WT) of liquid flowing from the inlet 14 into the receiving flow path 15, that is, the ratio (WA/WT):(WB/WT). In the example of FIG. 1, the flow rate ratio generally corresponds to the distribution ratio, and a change in the flow rate ratio is achieved by controlling (e.g., changing) the distribution ratio.
  • In cases where the bubble generating unit, which will be described later, is a cavitation-type device, the concentration of fine bubbles generated in the liquid passing through the bubble generating unit is said to depend on the flow velocity, pressure, and flow rate of the liquid. Therefore, when the bubble generating unit is a cavitation-type device, if the flow velocity, pressure, or flow rate of the liquid supplied to the inlet 14 differs, or if the inner diameter of the pipe member 20 differs between the first flow path 11A and the second flow path 11B, the bubble concentration in the entire liquid flowing out of the outlet of the bubble concentration adjustment device 10 may differ, even with the same distribution ratio. From this standpoint, it is preferable to pre-construct a database such as a correspondence table that indicates the relationship among the flow velocity, pressure, and flow rate of the liquid supplied to the inlet 14, and/or the flow rate ratio in the flow rate ratio control unit 12, and the concentration (bubble concentration) of fine bubbles in the entire liquid ultimately flowing out of the outlet of the bubble concentration adjustment device 10. It is also preferable that the flow rate ratio control unit 12 be configured to be capable of controlling the flow rate ratio of the liquid flowing through the plurality of flow paths 11 in accordance with the pressure, flow velocity, and flow rate of the liquid received from the inlet 14.
    • (Bubble Generating Unit)
  • At least one of the plurality of flow paths 11 is provided with a bubble generating unit 13. The bubble generating unit 13 generates bubbles in the liquid flowing through the flow path 11 in which it is provided. In the example shown in FIG. 1, the bubble generating unit 13 is provided in the first flow path 11A, and generates bubbles in the liquid flowing through the first flow path 11A. As a result, the liquid flowing through the first flow path 11A becomes a gas-liquid mixture in which bubbles are dispersed in the liquid component after passing through the bubble generating unit 13.
    • (Bubbles)
  • At least a portion of the bubbles generated by the bubble generating unit 13 has a bubble diameter of less than 1 µm (that is, the average bubble diameter of at least some of the bubbles is less than 1 µm). However, it is preferable that all the bubbles generated by the bubble generating unit 13 have a diameter of less than 1 µm (that is, the average bubble diameter of all the generated bubbles is less than 1 µm). Bubbles having a diameter of 100 µm or less may be referred to as "fine bubbles." Among them, bubbles having a diameter of 1 µm or more and 100 µm or less may be referred to as "microbubbles," and bubbles having a diameter of less than 1 µm may be referred to as "ultrafine bubbles" or "nanobubbles." The term "fine bubbles" is used herein to collectively refer to both microbubbles and ultrafine bubbles. It is preferable that at least some of the bubbles generated by the bubble generating unit 13 are ultrafine bubbles. For example, in the example shown in FIG. 1, at least some of the bubbles generated by the bubble generating unit 13 in the liquid flowing through the first flow path 11A are ultrafine bubbles. The gas-liquid mixture, as the liquid containing bubbles formed in the first flow path 11A, is in a state where ultrafine bubbles are dispersed in the liquid. In addition, this does not exclude the possibility that the gas-liquid mixture formed in the first flow path 11A contains bubbles other than ultrafine bubbles, and microbubbles or the like may also be included in the gas-liquid mixture.
    • (Components Inside Bubbles)
  • The gas components inside the bubbles generated by the bubble generating unit 13 are not particularly limited. They may be gases introduced from outside into the bubble generating unit 13, or may be gasifiable components dissolved in the liquid supplied to the bubble generating unit 13. For example, in the case where the liquid is water, the gasifiable components dissolved in the liquid may include dissolved carbon dioxide, dissolved oxygen (oxygen that was dissolved in water), and dissolved nitrogen (nitrogen that was dissolved in water), among others.
    • (Bubble Diameter)
  • The bubble diameter refers to the diameter of a bubble. The average bubble diameter refers to the average value of the diameters of the bubbles. The average bubble diameter can be determined from the bubble diameter distribution. The average bubble diameter of a portion of the bubbles can also be determined from the bubble diameter distribution. The bubble diameter can be determined when measuring the bubble diameter distribution. The bubble diameter and the average bubble diameter can be determined using techniques for measuring the bubble diameter distribution (particle size distribution) of the bubbles contained in the gas-liquid mixture. Examples of techniques for measuring the bubble diameter distribution (particle size distribution) include methods using laser diffraction/scattering type particle size distribution measuring devices. In addition, examples of methods for determining the bubble diameter distribution include particle size analysis based on the particle tracking analysis method conforming to JIS Z 8829:2021.
    • (Bubble Concentration)
  • The bubble concentration (number of bubbles per cm3) in the gas-liquid mixture generated by the bubble generating unit 13 is not particularly limited. However, even in the case where a mixed liquid is assumed that dilutes the bubble concentration by mixing the liquids flowing out of the plurality of flow paths 11 (that is, in the example of FIG. 1, the mixed liquid of the liquid flowing out of the first flow path 11A and the liquid flowing out of the second flow path 11B), it is preferable, from the viewpoint of maintaining the effects of the bubbles in the mixed liquid to some extent, that the bubble concentration of bubbles having a diameter of less than 1 µm in the gas-liquid mixture is 20 million bubbles/cm3 or more, more preferably 50 million bubbles/cm3, and still more preferably 60 million bubbles/cm3 or more. If the liquid contains 20 million bubbles/cm3 or more of bubbles having a diameter of less than 1 µm, the gas-liquid mixture can exhibit an anti-fouling effect. If the number of such bubbles is 50 million bubbles/cm3 or more, it can exhibit a cleaning effect on biofilms (aggregates formed on solid surfaces by microorganisms, etc.). If the number of such bubbles is 60 million bubbles/cm3 or more, these effects can be further enhanced. Since the bubble concentration of the mixed liquid can be increased up to the bubble concentration of the gas-liquid mixture, the effects obtained in the case where the gas-liquid mixture satisfies the above bubble concentration range can also be realized in the mixed liquid.
  • The upper limit of the bubble concentration in the gas-liquid mixture generated by the bubble generating unit 13 is not particularly limited. However, from the viewpoint of ease of stable bubble generation, it is preferable that the upper limit of the bubble concentration in the gas-liquid mixture be 5 billion bubbles/cm3. The bubble concentration can be determined using the same methods exemplified above for specifying the bubble diameter or average bubble diameter of the bubbles. In addition, the expression that the bubble concentration is preferably K1 (bubbles/cm3) or more means that the lower limit of the bubble concentration is preferably K1 (bubbles/cm3), and the bubble concentration (bubbles/cm3) may be within a range defined by its lower and upper limits.
    • (Electric Potential of Bubbles)
  • It is preferable that the bubbles contained in the gas-liquid mixture have a negative electric potential. The negatively charged state of the bubbles can be realized depending on the magnitude of static electricity generated by cavitation in the liquid flowing through the flow path of the bubble generating unit 13-which will be described later-when it is a cavitation-type bubble generating device (e.g., the bubble generating device 100), and by friction of the fluid within the flow path (i.e., friction between the member forming the flow path and the bubbles). The magnitude of the negative potential can be determined depending on various conditions, such as the diameter of the bubbles.
    • (Production of Gas-Liquid Mixture)
  • As described above, the gas-liquid mixture can be produced, for example, by allowing the liquid component serving as the raw material of the gas-liquid mixture to pass through the bubble generating unit 13.
  • The bubble generating unit 13 is configured to be capable of generating fine bubbles, such as ultrafine bubbles, in a liquid as bubbles, and forming a gas-liquid mixture in which the bubbles are dispersed in the liquid. As such a bubble generating unit, it is possible to exemplify a device (bubble generating device) that applies, as necessary, various types of bubble generating mechanisms such as cavitation type, microporous type, ultrasonic type, swirling flow type, static mixer type, Venturi type, steam condensation type, pressurized dissolution type, and gas-liquid mixing shear type.
  • However, from the viewpoint of efficiently generating fine bubbles such as ultrafine bubbles having a negative electric potential as the bubbles contained in the gas-liquid mixture, it is preferable to adjust the gas-liquid mixture by using a cavitation-type device as the bubble generating unit 13. As a cavitation-type device, a device such as that shown in the following "Example of a Bubble Generating Device" can be used. Next, an example of a bubble generating device that can be applied as the bubble generating unit 13 will be described with reference to FIGS. 2A to 2D.
    • (Example of a Bubble Generating Device)
  • As shown in FIGS. 2A to 2D, a bubble generating device 100 includes: a receiving unit 110 for receiving a liquid component serving as the raw material (referred to as "raw material liquid"); a bubble generating mechanism 120 for generating a gas-liquid mixture in which bubbles are dispersed in the raw material liquid supplied from the receiving unit 110; and a discharge unit 130 for discharging the gas-liquid mixture. FIGS. 2A to 2D illustrate one example of a bubble generating device. FIG. 2D is a schematic enlarged cross-sectional view showing an enlarged portion of the region SP enclosed by a dashed line in FIG. 2C. When the bubble generating device 100 is applied as the bubble generating unit 13 shown in the example of FIG. 1, the raw material liquid is the liquid flowing through the first flow path 11A among the liquid supplied from the inlet 14. The gas-liquid mixture flowing out from the discharge unit 130 further flows toward the outlet (not shown) of the first flow path 11A.
    • (Bubble Generating Mechanism)
  • The bubble generating mechanism 120 includes a flow path forming body 121 and a plurality of collision elements 124. The flow path forming body 121 forms a liquid flow path 122 on its inner peripheral surface 121A and includes a constricted structure 123. The constricted structure 123 includes a first portion 123A, in which the cross-sectional diameter (as determined in a cross section taken on a plane perpendicular to the longitudinal direction of the liquid flow path 122) of the inner peripheral surface 121A decreases from the upstream end 125 (inlet) toward the downstream end 126 (outlet), and a second portion 123B, in which the cross-sectional diameter of the inner peripheral surface 121A increases from the upstream end 125 toward the downstream end 126. The first portion 123A is located upstream of the second portion 123B. The plurality of collision elements 124 protrude inward from the inner peripheral surface 121A of the flow path forming body 121 and are arranged adjacent to each other across a segment region 150. The collision elements 124 are disposed at a position between (or at the boundary of) the first portion 123A and the second portion 123B in the longitudinal direction of the liquid flow path 122. However, this does not preclude the possibility that the collision elements 124 are formed in either the first portion 123A or the second portion 123B. The segment region 150 refers to a region in the cross section of the inner peripheral surface 121A that is divided in the circumferential direction by adjacent collision elements 124. The collision elements 124 are arranged to form a gap portion 151 that narrows the flow path between their tips. The bubble generating mechanism 120 is configured such that the flow path forming body 121 allows the raw material liquid to pass from the upstream end 125 to the downstream end 126.
  • As described above, it is preferable that a pump (not shown) for supplying the raw material liquid is installed on the upstream side and/or the downstream side of the bubble generating device 100. This pump supplies the raw material liquid to the bubble generating device 100 so that the water pressure, flow velocity, and flow rate of the raw material liquid each reach or exceed a predetermined value. In the bubble generating device 100, the concentration of fine bubbles (such as microbubbles and ultrafine bubbles) generated varies depending on the pressure, flow velocity, and flow rate of the liquid flowing through the liquid flow path 122. The bubble generating device 100 can generate a high concentration of fine bubbles in the liquid when at least one of the pressure, flow velocity, or flow rate of the liquid is increased.
    • (Production of Gas-Liquid Mixture)
  • By using the bubble generating device 100, a bubble-containing liquid can be obtained as described below. The raw material liquid is injected into the receiving unit 110 of the bubble generating device 100 as a liquid fluid. The receiving unit 110 is connected to the upstream end 125 (inlet) of the bubble generating mechanism 120, and the raw material liquid flows into the bubble generating mechanism 120 from the upstream end 125. In the bubble generating mechanism 120, the flow velocity of the raw material liquid is increased by moving through the first portion 123A of the constricted structure 123 in a direction generally from the upstream end 125 to the downstream end 126 (in the direction of arrow LF). The liquid proceeds to the gap portion 151 formed at the position where the collision elements 124 are arranged, and a portion of the raw material liquid further proceeds through the gap portion 151 toward the downstream end 126. At this time, another portion of the raw material liquid flows from the segment region 150 toward the downstream end 126, which prevents excessive increase in fluid resistance in the constricted structure 123 and enhances the negative pressure generation effect. As part of the raw material liquid passes through the gap portion 151, a cavitation effect occurs in the raw material liquid, causing dissolved components (e.g., dissolved oxygen) in the raw material liquid to be gasified into bubbles. The bubble size is adjusted according to the size of the gap portion 151 and the structure of the collision elements 124. In this way, a gas-liquid mixture is produced in which bubbles having a desired diameter are dispersed in the raw material liquid.
  • The produced gas-liquid mixture flows out through the downstream end 126 via the discharge unit 130.
  • The bubbles dispersed in the gas-liquid mixture obtained by the bubble generating device 100 are, as described above, formed by cavitation that occurs in the raw material liquid, and are gasified components that result from the cavitation of constituents dissolved in the raw material liquid. In such bubbles, gasified oxygen (dissolved oxygen) and nitrogen (dissolved nitrogen) originally dissolved in the water constituting the raw material liquid are contained. Note that the gaseous components in the bubbles may be determined in accordance with the intended effect expected from the gas-liquid mixture. For example, when the gas-liquid mixture is used to achieve an effect of removing biofilms, it is preferable that the oxygen content within the bubbles be low. In consideration of further enhancing the desired effect, it is preferable that the bubble generating device 100 be equipped with a gas supply structure.
  • As shown in FIG. 2, the bubble generating device 100 may be provided with a gas supply structure (not shown) for introducing a gas into the liquid flow path 122 from the outside, depending on the circumstances such as the effect required of the gas-liquid mixture, as described above. This also applies when the bubble generating device 100 is used as the bubble generating unit 13 or 280 in the examples shown in FIG. 1, FIGS. 3A to 3D, FIGS. 4A to 4C, and FIGS. 6 to 10, where the gas supply structure may be provided as needed. When the bubble generating device 100 is equipped with a gas supply structure that introduces an external gas (e.g., nitrogen or carbon dioxide) into the liquid flow path 122, the supplied gas is incorporated into the raw material liquid at the point of introduction in the form of bubbles and flows toward the downstream end 126 along with the flow of the raw material liquid. The bubbles formed from the gas supplied into the raw material liquid via the gas supply structure are finely divided by collisions with the collision elements 124 or the like, in the gap section 151 or the segment region 150, and are further refined. As a result, the bubbles can be reduced in size, for example, to a diameter of less than 1 µm.
  • The bubble generating device 100 described above can be applied as the bubble generating unit 13 of the bubble concentration adjustment device 10.
    • (Outlet)
  • In the bubble concentration adjustment device 10, outlets (not shown) for the liquid that has flowed through the flow paths 11 are provided at the downstream ends of the plurality of flow paths 11. In the example shown in FIG. 1, an outlet is formed at the downstream end of the first flow path for the liquid that has flowed through the first flow path in the direction of arrow FP1, and an outlet is formed at the downstream end of the second flow path for the liquid that has flowed through the second flow path in the direction of arrow FP2. The first and second flow paths are not connected to each other at their respective downstream ends, and each has its own outlet.
    • [Operation and Effects of the Bubble Concentration Adjustment Device]
  • In the bubble concentration adjustment device 10, the liquid supplied from the inlet 14 to the receiving flow path 15 is distributed to the plurality of flow paths 11 (the first flow path 11A and the second flow path 11B) by the flow rate ratio control unit 12, and the amount (flow rate) of liquid flowing through each flow path 11 is determined according to the control of the flow rate ratio. At least one of the flow paths 11 (the first flow path 11A) is provided with a bubble generating unit 13, and bubbles are generated in the liquid flowing through the bubble generating unit 13. Since the flow rate of the liquid flowing through the flow path 11 (the first flow path 11A) provided with the bubble generating unit 13 is determined according to the state of flow rate ratio control by the flow rate ratio control unit 12, the amount of bubbles generated in the liquid is also determined. Accordingly, the bubble concentration in the mixed liquid, which is assumed to be a combination of the liquids flowing out of the outlets of the plurality of flow paths 11, is determined. That is, according to the bubble concentration adjustment device 10 described above, the concentration of bubbles in the liquid obtained by mixing the liquids flowing out of the outlet of the bubble concentration adjustment device 10 is determined according to the control of the flow rate ratio by the flow rate ratio control unit 12. Therefore, according to the bubble concentration adjustment device 10, it is possible to obtain a liquid having a desired bubble concentration by controlling the flow rate ratio.
  • According to the bubble concentration adjustment device 10, the concentration of fine bubbles can be adjusted by mixing the liquid containing a high concentration of fine bubbles, which has passed through the bubble generating unit 13 of the first flow path 11A, and the liquid that has flowed through the second flow path 11B branched by the distribution valve 21, thereby diluting the liquid containing the high concentration of fine bubbles. Therefore, as in the conventional technique, in which the concentration of fine bubbles in the liquid is adjusted solely by the bubble generating device without using a structure such as the distribution valve 21, the bubble concentration adjustment device 10 makes it possible to obtain a large amount of liquid containing fine bubbles at an adjusted concentration. In addition, the above-described liquid containing fine bubbles obtained by the bubble concentration adjustment device 10 contains, at least partially, microfine bubbles.
  • In the conventional technique, when a single flow path is provided for supplying liquid from the inlet, and a bubble generating device is provided in the single flow path, and the bubble concentration is simply adjusted by the flow rate, flow velocity, and pressure, there is a possibility that it becomes necessary to reduce the flow rate of the liquid flowing in from the inlet in order to obtain a liquid containing fine bubbles at a desired concentration. In such a case, the amount that can be supplied to a tank or the like per unit time is reduced, and it takes time for the tank to be filled. In contrast, with the bubble concentration adjustment device 10, it is possible to obtain a liquid containing fine bubbles at a desired concentration (containing, at least partially, microfine bubbles) while maintaining the flow rate of the liquid flowing in from the inlet, thereby suppressing the possibility of a reduction in the amount that can be supplied to the tank or the like per unit time.
    • [Modified Example of Bubble Concentration Adjustment Device] (Modified Example 1)
  • In the bubble concentration adjustment device 10 (referred to as bubble concentration adjustment device 10A in FIG. 3A), as shown in FIG. 3A, the device may be configured such that the liquid that has flowed through the plurality of flow paths 11 merges on the downstream side. This is referred to as Modified Example 1. FIG. 3A is a schematic diagram illustrating one example of the bubble concentration adjustment device 10A according to Modified Example 1. In the example of Modified Example 1 shown in FIG. 3A, there is a single outlet, and an outlet common to the plurality of flow paths 11 is provided. In the example of FIG. 3, the first flow path 11A and the second flow path 11B are connected at a position SC on the downstream side of the bubble generating unit 13 in the first flow path 11A. The downstream position SC is a location at which the liquids that have flowed through the plurality of flow paths 11 merge on the downstream side.
    • (Modified Example 2)
  • In the bubble concentration adjustment device 10 (referred to as bubble concentration adjustment device 10B in FIG. 3B), as shown in FIG. 3B, bubble generating units 13 may be provided in the plurality of flow paths 11. This is referred to as Modified Example 2. FIG. 3B is a schematic diagram illustrating one example of the bubble concentration adjustment device 10B according to Modified Example 2. In the example of Modified Example 2 shown in FIG. 3B, the bubble generating units 13 are provided in the first flow path 11A and the second flow path 11B. When three or more flow paths 11 are formed, the bubble generating units 13 may be provided in two of the flow paths 11, or in all three of the flow paths 11 (none of which is shown). In this case, among the liquids flowing through the flow paths 11 (those in which the bubble generating units 13 are installed) branched by the distribution valve 21, fine bubbles can be generated at a higher concentration in the liquid having a greater flow velocity and/or flow rate. This is particularly more feasible when the bubble generating unit is a cavitation-type device.
    • (Modified Example 3)
  • In the bubble concentration adjustment device 10 shown in the example of FIG. 1, the flow rate ratio control unit 12 has a structure in which the flow rate control member 16 is provided so as to connect the lower end of the receiving flow path 15 to the upstream ends of the first flow path 11A and the second flow path 11B. However, the flow rate ratio control unit 12 is not limited to this configuration. In the bubble concentration adjustment device 10 (referred to as bubble concentration adjustment device 10C in FIG. 3C), as shown in FIG. 3C, the flow rate control member 16 in the flow rate ratio control unit 12 may be provided at a position offset from the lower end position of the receiving flow path 15. This is referred to as Modified Example 3. FIG. 3C is a schematic diagram illustrating one example of the bubble concentration adjustment device 10C according to Modified Example 3.
  • In the bubble concentration adjustment device according to Modified Example 3 shown in the example of FIG. 3C, the receiving flow path is integrated with the first flow path, and a portion extending from the upstream end of the first flow path to a predetermined position SV along the longitudinal direction of the first flow path serves also as the receiving flow path. The predetermined position SV of the first flow path is a position where the second flow path branches from the first flow path. The upstream end of the second flow path is connected to the predetermined position SV of the first flow path. The flow rate ratio control unit 12 is composed of the flow rate control member 16 and a structure in which the second flow path branches from the first flow path.
  • As the flow rate control member 16, a control valve 22 is provided instead of the distribution valve 21 shown in the example of FIG. 1. The control valve 22 is a valve for controlling the flow rate of the liquid flowing through the flow path 11 in which it is installed, and preferably has a function of opening and closing the flow path 11. In the example of Modified Example 3 shown in FIG. 3C, the control valve 22, which serves as the flow rate control member 16, is provided in the second flow path 11B and controls the amount of liquid flowing in the direction of arrow FP2 toward the downstream end within the second flow path 11B. In this example, when the amount of the liquid, out of the liquid flowing through the receiving flow path 15 (the portion upstream of the predetermined position SV of the first flow path 11A), that flows into the second flow path 11B is changed, the amount of liquid flowing through the first flow path 11A is also changed accordingly. Therefore, the ratio between the amount of liquid flowing through the first flow path 11A and the amount of liquid flowing through the second flow path 11B is determined by the control of the control valve 22.
  • In the example shown in FIG. 3C, the control valve 22 was provided in the second flow path 11B. However, in Modified Example 3, as shown in another example of the bubble concentration adjustment device 10C illustrated in FIG. 3D (referred to as bubble concentration adjustment device 10D in FIG. 3D), the control valve 22 may alternatively be provided in the first flow path 11A. In the bubble concentration adjustment device 10D as well, the ratio between the amount of liquid flowing through the first flow path 11A and the amount of liquid flowing through the second flow path 11B is determined by the control of the control valve 22.
  • In Modified Example 3, as shown in another example of the bubble concentration adjustment device 10C illustrated in FIG. 4A (referred to as bubble concentration adjustment device 10E in FIG. 4A), the control valve 22 may also be provided in both the first flow path 11A and the second flow path 11B. In this case, the flow rate ratio control unit 12 includes a plurality of flow rate control members 16, and the plurality of flow rate control members 16 include a plurality of control valves 22.
    • (Modified Example 4)
  • In the bubble concentration adjustment device 10, as shown in FIG. 5A, the flow rate ratio control unit 12 may include an operation unit 42, and the operation unit 42 may be provided with a scale display unit 40 having a scale 41 as a concentration display unit that indicates a bubble concentration corresponding to the flow rate ratio. This is referred to as Modified Example 4. FIG. 5A is a diagram illustrating an example of the scale display unit 40 of the flow rate ratio control unit 12 used in one example of the bubble concentration adjustment device 10 according to Modified Example 4.
  • The operation unit 42 of the flow rate ratio control unit 12 is configured to perform an operation for changing the flow rate ratio. The operation unit 42 may be formed integrally with the flow rate control member 16 or may be formed separately therefrom. In the example of Modified Example 6 shown in FIG. 5A, the operation unit 42 is provided with a knob 42A. In the example of FIG. 5A, the knob 42A is rotatably mounted, and when the rotation position of the knob 42A is changed by rotating it, the flow rate ratio control unit 12 changes the flow rate ratio between the liquid flowing through the first flow path and the liquid flowing through the second flow path so that the flow rate ratio corresponds to the value of the scale 41 (i.e., the value indicated at the outer position along the longitudinal direction of the knob 42A) determined in accordance with the rotation position. For convenience of explanation, FIG. 5A shows the values of the scale 41 as numerals from 1 to 5, but this is merely an example. In FIG. 5A, the rotation direction of the knob 42A is indicated by an arrow RT.
  • The scale display unit 40 is provided with indicia (such as numbers or marks that are visually identifiable) as the scale 41, which indicate information corresponding to the bubble concentration of the entire liquid (gas-liquid mixture) flowing out of the outlet. The flow rate ratio can be associated in advance with the bubble concentration. The term "bubble concentration" here refers to the bubble concentration in a mixed liquid that is defined on the assumption that the liquids having passed through the plurality of flow paths 11 are mixed. When the bubble generating unit 13 is a cavitation-type device, it is particularly preferable that the flow rate ratio be associated in advance with the bubble concentration according to the pressure, flow velocity, and flow rate of the liquid flowing into the flow paths 11. Also, the flow rate ratio can be associated with the state of the flow rate control member 16. The scale display unit 40 indicates, as the value of the scale 41, the bubble concentration determined from the state of the flow rate control member 16, corresponding to each state of the flow rate control member 16. The flow rate ratio control unit 12 changes the flow rate ratio according to the bubble concentration (the value shown on the scale 41) displayed on the scale display unit 40. Therefore, once the value of the scale 41 is determined, the target bubble concentration is specified, and the flow rate ratio according to the pressure, flow velocity, and flow rate of the liquid flowing into the flow paths 11 is also determined, and the state of the flow rate control member 16 is controlled so as to approximately realize the flow rate ratio. Thus, the flow rate ratio control unit 12 changes the flow rate ratio in accordance with the scale 41 of the scale display unit 40.
  • The scale display unit 40 may include, as the scale 41, either an evenly spaced scale or a logarithmic scale. In the example of FIG. 5A, the scale 41 is configured as a fixed design; however, the scale 41 in the scale display unit 40 may alternatively be configured as a digital display. It is sufficient that the scale 41 of the flow rate ratio control unit 12 corresponds to the concentration of fine bubbles ultimately contained in the entirety of the liquid flowing out of the outlet.
  • For example, in the example shown in FIG. 1, if the flow rate ratio between the liquid flowing through the first flow path 11A and the liquid flowing through the second flow path 11B is WA:WB (i.e., the ratio of the flow rate of the liquid flowing through the first flow path 11A to the flow rate of the liquid flowing through the second flow path 11B), the bubble concentration (bubbles/cm3) NT in the liquid that has flowed through the first flow path 11A (passed through the bubble generating unit 13), and the bubble concentration in the liquid that has flowed through the second flow path 11B is approximately zero, then the bubble concentration (NT) of the liquid (mixed liquid) determined assuming the entire liquid flowing out of the outlet is given by: NT = N1 × (WA / (WA + WB)). In the example of FIG. 1, the correspondence between the bubble concentration NT of the mixed liquid and WA:WB is predetermined. Also, since the rotation position of the knob corresponds to WA:WB, the rotation position of the knob can be associated with the bubble concentration NT. In the scale display unit 40, the value of the scale 41 is provided at a predetermined position so that the rotation position of the knob 42A and the bubble concentration NT can be visually recognized. For example, in FIG. 5A, the scale 41 indicates "2", and the flow control member 16 changes the flow rates of the liquid flowing through the first flow path 11A and the second flow path 11B as necessary so that WA:WB realizes a bubble concentration NT corresponding to the value "2".
  • In Modified Example 4, the bubble concentration NT is not limited to being associated with the rotation position of the knob 42A. For example, as shown in FIG. 5B, the knob 42A may be omitted, and the operation unit 42 of the flow rate ratio control unit 12 may be provided with an input unit 44 for bubble concentration as a concentration display unit instead of the scale display unit 40. The operation unit 42 has previously stored data regarding the correspondence between the flow rate ratio and the bubble concentration in accordance with the pressure, flow velocity, and flow rate of the liquid flowing into the flow path 11. When a bubble concentration value is input via the input unit 44, the operation unit 42 determines the flow rate ratio based on the input bubble concentration value and in accordance with conditions such as the pressure, flow velocity, and flow rate of the liquid, and controls the state of the flow rate control member 16 so that the determined flow rate ratio is achieved.
  • That is, in the bubble concentration adjustment device 10, a computer is provided which stores a database such as a correspondence table indicating the relationship between various conditions related to the liquid flowing into the flow path 11-such as pressure, flow velocity, flow rate, and flow rate ratio-and the concentration of fine bubbles (bubble concentration) in the entire liquid flowing out from the outlet. The input unit 44 is connected to the computer. Based on the fine bubble concentration value (bubble concentration value) input via the input unit 44, the computer refers to the database such as a correspondence table showing the relationship between the aforementioned conditions of the liquid flowing into the flow path 11 and the fine bubble concentration, and the state of the distribution valve 21 (i.e., the state of the flow rate control member 16) may be controlled accordingly. It is preferable that the operation unit 42 includes a display unit 43 that displays the value input via the input unit 44.
  • According to Modified Example 4, the operator can perform operations for obtaining a liquid having a desired bubble concentration while visually recognizing the operation procedure, thereby suppressing the risk that a liquid with an unintended bubble concentration is erroneously generated.
    • (Modified Example 5)
  • In the bubble concentration adjustment device 10 (referred to as bubble concentration adjustment device 10F in Fig. 4B) of Modified Example 4, as shown in Fig. 4B, the flow rate ratio control unit 12 may further include a status checking unit 30. This is referred to as Modified Example 5. Fig. 4B is a schematic diagram illustrating an example of the bubble concentration adjustment device 10F according to Modified Example 5.
  • The status checking unit 30 is configured to check whether the states of the plurality of flow paths 11 are in a condition capable of achieving the bubble concentration (i.e., the bubble concentration of the mixed liquid) set by the operation unit 42. In the example shown in Fig. 4B, the status checking unit 30 includes a flow rate sensor (first flow rate sensor 31A) for measuring the flow rate of the liquid flowing through the first flow path 11A, and a flow rate sensor (second flow rate sensor 31B) for measuring the flow rate of the liquid flowing through the second flow path 11B.
  • In the bubble concentration adjustment device 10F shown in the example of FIG. 4B, the bubble concentration (bubble concentration based on actual measurement) of the entire liquid (mixed liquid) flowing out from the outlet is determined based on the measurement values of the first flow rate sensor 31A and the second flow rate sensor 31B.
    In the bubble concentration adjustment device 10F, as shown in the example of FIG. 4B, a measurement result display unit 33 may be provided. The measurement result display unit 33 displays information for recognizing the presence or absence of a difference between the bubble concentration based on the actual measurement and the bubble concentration determined by the operation unit 42 (e.g., numerical data indicating the difference between the measured bubble concentration and the value determined by the operation unit 42). In the example of FIG. 4B, the first flow rate sensor 31A, the second flow rate sensor 31B, the measurement result display unit 33, and the operation unit 42 are electrically connected via wiring or the like to allow signal transmission. However, this is merely an example, and these components may be wirelessly connected so that signals can be transmitted. This also applies to FIGS. 4C, 7, 9, and 10.
    • (Modified Example 6)
  • In the bubble concentration adjustment device 10 (referred to as bubble concentration adjustment device 10G in FIG. 4C), as shown in FIG. 4C, a sensor 34 may be connected to the bubble generating unit 13. This is referred to as Modified Example 6. FIG. 4C is a schematic diagram illustrating an example of the bubble concentration adjustment device 10G according to Modified Example 6.
    • (Sensor)
  • The sensor 34 is not particularly limited as long as it detects at least one of the pressure, flow velocity, and flow rate of the liquid flowing through the bubble generating unit 13. By comparing the expected condition of the liquid flowing through the bubble generating unit 13 under the assumption that the bubble generating unit 13 is operating normally, with the condition of the liquid based on the values measured by the sensor 34, it is possible to confirm whether the bubble generating unit 13 is in normal operation.
    • [2. Tank System]
  • The tank system of the present invention will be described.
    • [2-1. First Embodiment] [Configuration]
  • The tank system 200 according to the first embodiment includes, as shown in FIG. 6, a tank 210 as a tank body for storing a liquid (storage liquid GL), and a bubble concentration adjustment device 220. The bubble concentration adjustment device 220 includes a plurality of flow paths 270 (a first flow path 270A and a second flow path 270B), a flow rate control member 290, a flow rate ratio control unit 295, an inlet 260, an outlet 250, and a bubble generating unit 280. The bubble concentration adjustment device 220 can apply the bubble concentration adjustment device 10 described in "1. Bubble Concentration Adjustment Device," including its modified examples. The plurality of flow paths 270 (the first flow path 270A and the second flow path 270B), the flow rate control member 290, the flow rate ratio control unit 295, the inlet 260, the outlet 250, and the bubble generating unit 280 correspond to the plurality of flow paths 11 (the first flow path 11A and the second flow path 11B), the flow rate control member 16, the flow rate ratio control unit 12, the inlet 14, the outlet (not shown), and the bubble generating unit 13 of the bubble concentration adjustment device 10, respectively. Accordingly, a detailed description of each component of the bubble concentration adjustment device 220 is omitted. FIG. 6 is a schematic diagram illustrating a configuration of an example of the tank system according to the first embodiment. The example shown in FIG. 6 illustrates a case in which the bubble concentration adjustment device 10 shown in FIG. 1 is applied as the bubble concentration adjustment device 220.
    • (Tank)
  • The tank 210 is not particularly limited as long as it has a space 230 in which a liquid (storage liquid GL) can be stored therein. In the example shown in FIG. 6, the tank 210 has a structure in which the upper surface serves as an opening 240, although this is merely an example. As the tank 210, examples that can be used include a water storage tank installed in various types of buildings such as office buildings and apartment complexes, a facility such as a swimming pool, a bathtub provided in a bathroom or public bathhouse, a tank that stores a coolant for a cooling device, a storage tank connected to various devices and used to store liquid to be supplied to such devices, a storage unit mounted in a cleaning device, a fuel storage tank capable of storing reserve fuel or the like, a water tank for aquaculture of fish and the like, and a tank used for nutrient solution cultivation.
    • (Tank and Bubble Concentration Adjustment Device Arrangement)
  • In the tank system 200, the configuration in which the tank 210 and the bubble concentration adjustment device 220 are arranged is not particularly limited as long as the liquid is supplied to the tank 210 after passing through the bubble concentration adjustment device 220. In the example of FIG. 6, the outlet 250 of the bubble concentration adjustment device 220 is located below the opening on the upper surface of the tank 210 (i.e., within the space 230), but this is merely an example. It suffices that the liquid having generated bubbles (fine bubbles and ultrafine bubbles) by passing through the first flow path 270A of the bubble concentration adjustment device 220 and the liquid that has passed through the second flow path 270B are supplied to the tank 210.
    • (Storage Liquid Discharge Unit)
  • In the first embodiment, as shown in FIG. 6, a storage liquid discharge unit 300 may be provided. The storage liquid discharge unit 300 is not particularly limited as long as it has a structure for discharging the liquid (storage liquid GL) stored in the tank 210 to the outside. The storage liquid discharge unit 300 includes a discharge flow path 310 for delivering the storage liquid to the outside. Additionally, a pump 320 for delivering the storage liquid GL into the discharge flow path 310 may be provided as needed. The discharge flow path 310 may be formed using piping or the like made of the same material as the pipe member 20 that constitutes the flow paths 11, for example.
    • [Operations and Effects]
  • In the tank system 200 according to the first embodiment, since the bubble concentration adjustment device 220 described above is provided, the gas-liquid mixture with an adjusted bubble concentration flowing out from the flow outlet 250 can flow into the tank, and the gas-liquid mixture can be stored in the tank 210. Therefore, in the tank system 200 according to the first embodiment, it is possible to use, as the stored liquid GL in the tank 210, a liquid (gas-liquid mixture) having a bubble concentration adjusted according to the user's requirements.
    • [Modified Example of First Embodiment] (Modified Example 1 of the First Embodiment)
  • In the tank system 200 (referred to as tank system 200A in FIG. 7) according to the first embodiment, an inflow amount control structure 330 may be provided, as shown in FIG. 7. This is referred to as Modified Example 1 of the first embodiment. FIG. 7 is a schematic diagram illustrating a configuration of an example of the tank system 200A according to Modified Example 1 of the first embodiment.
    • (Inflow Amount Control Structure)
  • The inflow amount control structure 330 includes a concentration sensor 331 for measuring the bubble concentration in the stored liquid in the tank. Examples of the concentration sensor 331 include sensors that employ laser diffraction/scattering methods. As the concentration sensor, a sensor device using green laser light can be used. In FIG. 7, reference numeral 332 denotes wiring. The wiring 332 in FIG. 7 transmits signals for controlling the state of the flow rate control member 290.
  • In the inflow amount control structure 330, the bubble concentration in the tank 210 is measured by the concentration sensor 331. When the value specified by the concentration sensor 331 differs from a desired concentration, the flow rate ratio control unit 295 is controlled by adjusting the flow rate control member 290 so that the bubble concentration of the overall liquid (i.e., the mixed liquid obtained by combining the liquids that have passed through each of the plurality of flow paths) flowing from the outlet 250 of the bubble concentration adjustment device 220 into the tank 210 reaches a predetermined concentration. For example, when the bubble concentration M1 in the tank 210 is lower than a desired bubble concentration M2, the state of the flow rate control member 290 is controlled as needed to introduce a gas-liquid mixture with a bubble concentration M3, which has passed through the first flow path 270A of the bubble concentration adjustment device 220, into the tank. The bubble concentration M3 is set to be higher than the bubble concentration M2. When the bubble concentration in the tank 210 increases to M2, the supply of the gas-liquid mixture from the bubble concentration adjustment device 220 is stopped. Additionally, when the bubble concentration M1 in the tank 210 is higher than a desired bubble concentration M4, the state of the flow rate control member 16 is controlled as needed to introduce into the tank the liquid that has flowed through the second flow path 270B of the bubble concentration adjustment device 220 (the bubble concentration of which is lower than M4 or zero). Then, when the bubble concentration in the tank 210 decreases to M4, the pouring of the gas-liquid mixture from the bubble concentration adjustment device 220 into the tank 210 is stopped.
    • (Operation and Effect)
  • In the case where the bubble diameter is extremely small, for example, less than 1 µm, such bubbles are considered to be capable of remaining in the liquid for a certain period of time. Therefore, according to the tank system 200 of Modified Example 1 of the first embodiment, when it is necessary to change the bubble concentration of the liquid (stored liquid GL) that has flowed into the tank 210 from the outlet 250, it is possible to re-adjust the bubble concentration by adding another liquid having a different bubble concentration into the tank 210.
  • According to the tank system 200 of Modified Example 1 of the first embodiment, by using in combination the position sensor described in Modified Example 2 of the first embodiment, which will be described later, it is also possible to adjust the amount of storage liquid in the tank 210 to a desired amount while setting the bubble concentration to a desired value.
    • (Modified Example 2 of the First Embodiment)
  • In the tank system 200A according to Modified Example 1 of the first embodiment, it may be configured such that the amount of liquid in the tank 210 is detected and liquid is replenished from the bubble concentration adjustment device 220 in accordance with the amount of liquid in the tank 210 (not shown). This is referred to as Modified Example 2 of the first embodiment. Modified Example 2 of the first embodiment may be configured similarly to Modified Example 1 of the first embodiment, except that a position sensor for detecting the liquid level is used in the tank 210 instead of the concentration sensor 331. According to Modified Example 2 of the first embodiment, a state in which a fixed amount of gas-liquid mixture with an adjusted bubble concentration is stored in the tank 210 can be maintained.
    • [2-2. Second Embodiment] [Configuration]
  • A tank system 200 according to the second embodiment (referred to as tank system 200B in FIG. 8) includes, as shown in FIG. 8, a tank (referred to as tank 210A in FIG. 8) for storing a liquid, and a bubble concentration adjustment device 220. The bubble concentration adjustment device 220 can apply the bubble concentration adjustment device 10 described in the above section "1. Bubble Concentration Adjustment Device" (including all the modifications except for Modified Example 1 shown in FIG. 3A). Accordingly, detailed explanation of the configuration of the bubble concentration adjustment device 220 is omitted. In addition, FIG. 8 is a schematic diagram illustrating a configuration of an example of the tank system according to the second embodiment. In the example of FIG. 8, the bubble concentration adjustment device 10 shown in FIG. 1 is applied as the bubble concentration adjustment device 220.
    • (Tank)
  • The tank 210A has a space 230 for storing a liquid therein, and the internal space 230 is partitioned into multiple sections, forming a plurality of spatial portions. In the example shown in FIG. 8, the internal space of the tank is partitioned into a first spatial portion 231A and a second spatial portion 231B. In this example, the tank 210A has an open-top structure, although this is merely one example. As with the first embodiment, examples that can be used for the tank 210A include a water storage tank installed in various types of buildings such as office buildings and apartment complexes, a tank that stores a coolant for a cooling device, a storage tank connected to various devices and used to store liquid to be supplied to such devices, a storage unit mounted in a cleaning device, a fuel storage tank capable of storing reserve fuel or the like, a water tank for aquaculture of fish and the like, and a tank used for nutrient solution cultivation.
    • (Arrangement of the Tank and the Bubble Concentration Adjustment Device)
  • In the tank system 200B, the tank 210A and the bubble concentration adjustment device 220 may be arranged such that the liquid, after passing through the bubble concentration adjustment device 220, is supplied from the respective outlets 250 to the respective space portions of the tank 210A (i.e., the first space portion 231A and the second space portion 231B), and the structure for arranging the tank 210A and the bubble concentration adjustment device 220 is not particularly limited. In the example shown in FIG. 8, the outlet 250 of the first flow path 270A is located directly above the first space portion 231A, and the outlet 250 of the second flow path 270B is located directly above the second space portion 231B; however, this is merely an example.
    • (Storage Liquid Discharge Unit)
  • In the second embodiment, as shown in FIG. 8, a storage liquid discharge unit 300 (referred to as storage liquid discharge unit 300A in FIG. 8) may be provided. The storage liquid discharge unit 300A is not particularly limited as long as it has a structure capable of discharging the storage liquid stored in the respective space portions (the first space portion 231A and the second space portion 231B) of the tank 210A to the outside. The storage liquid discharge unit 300A includes a discharge flow path 310 that delivers the storage liquid stored in the tank 210A to the outside. The discharge flow path 310 can be formed using piping or the like made of a material similar to that of the pipe member 20 constituting the flow path 11, for example. In the example shown in FIG. 8, the discharge flow path 310 includes a first discharge flow path 310A for discharging the storage liquid stored in the first space portion 231A and a second discharge flow path 310B for discharging the storage liquid stored in the second space portion 231B. The first discharge flow path 310A and the second discharge flow path 310B are connected at a predetermined position and extend to the outside of the tank 210A. A portion of the discharge flow path 310 that extends outward from the point where the first and second discharge flow paths 310A and 310B are joined is referred to as a mixed storage liquid discharge path 310C. The mixed storage liquid discharge path 310C allows the mixed liquid of the storage liquids from the first and second space portions 231A and 231B to flow therethrough. In the example shown in FIG. 8, a pump 320 for delivering the storage liquid into the discharge flow path 310 is provided in the mixed storage liquid discharge path 310C. Furthermore, a as shown in FIG. 8, a control valve 321 may be provided in the first discharge flow path 310A, the control valve 321 being configured to allow adjustment of the amount of storage liquid flowing through the first discharge flow path 310A.
    • [Operation and Effects]
  • In the tank system 200B according to the second embodiment, the above-described bubble concentration adjustment device 220A is provided, and the liquid that has flowed out from each of the outlets 250 can be stored in each of the space portions of the tank 210A. When the liquid is drawn from the tank 210A, it is possible to flow out to the outside the liquid (e.g., gas-liquid mixture) stored in each space portion in a mixed state. Therefore, in the tank system 200B according to the second embodiment, it becomes possible to flow out of the tank 210A a liquid (gas-liquid mixture) adjusted to various bubble concentrations in accordance with the user's requirements.
    • [2-3. Third Embodiment] [Configuration]
  • A tank system 200 according to a third embodiment (referred to as tank system 200C in FIG. 9) includes, as shown in FIG. 9, a tank 210B for storing a liquid, a flow path 340 for causing the liquid to flow, and a bubble generating unit 341. The tank 210B usable in the third embodiment is the same as the tank 210B described in the first embodiment, and therefore, detailed explanation is omitted. The bubble generating unit 341 is a device capable of generating bubbles having a diameter of less than 1 µm in the liquid (storage liquid) in the tank 210B. Since the same type of bubble generating unit as the bubble generating unit 13 provided in the bubble concentration adjustment device 10 described above in section "1. Bubble Concentration Adjustment Device" can be applied to the bubble generating unit 341, detailed explanation is also omitted. FIG. 9 is a schematic diagram illustrating a configuration of an example of the tank system 200C according to the third embodiment.
    • (Flow Path)
  • In the third embodiment, the flow path 340 is connected at both its upstream end PA and downstream end PB to the space 230 inside the tank 210B, and the liquid (storage liquid GL) in the tank 210B can flow through the flow path 340 in the direction of arrow FS and circulate between the tank 210B and the flow path 340. A bubble generating unit 341 is provided in the flow path 340, and when the liquid flowing into the flow path 340 from the upstream end PA passes through the bubble generating unit 341, bubbles are generated in the liquid. For example, the flow path 340 can be formed using piping or the like made of the same material as the pipe member 20 constituting the flow path 11.
    • (Storage Liquid Discharge Unit)
  • In the third embodiment, as shown in FIG. 9, a storage liquid discharge unit 300 may be provided. The storage liquid discharge unit 300 may have the same structure as that described in the first embodiment and the like, and therefore, detailed explanation is omitted.
    • (Circulation Flow Rate Control Valve)
  • In the tank system 200C, as shown in the example of FIG. 9, a circulation flow rate control valve 342, which is configured to allow adjustment of the flow rate of the liquid (storage liquid GL) flowing through the flow path 340, may be provided. The circulation flow rate control valve 342 may employ the same structure as the control valve 22 described in Modified Example 3 of the bubble concentration adjustment device 10.
    • (Timer)
  • In the tank system 200C, as shown in the example of FIG. 9, when the above-described circulation flow rate control valve 342 is provided, it is preferable that a timer 343 is also provided to set the time duration during which the circulation flow rate control valve 342 maintains a state that allows liquid to flow through the interior of the flow path 340. The timer 343 is preferably a timer switch that controls the state of the circulation flow rate control valve 342 upon the elapse of the set time. Furthermore, it is preferable that the circulation flow rate control valve 342 has a function for opening and closing the flow path 340. In this case, the tank system 200C becomes capable of controlling the open state of the flow path 11 so that liquid flows through the interior of the flow path 11 only for the time period defined by the timer 343.
  • In the tank system 200C according to the third embodiment, the timer 343 can be set to a time corresponding to a desired fine bubble concentration or ultrafine bubble concentration. By setting the time defined by the timer 343 to the time required for the bubble concentration (particularly, the fine bubble concentration or ultrafine bubble concentration) of the storage liquid GL to reach the desired value, a gas-liquid mixture having bubbles (particularly, fine bubbles or ultrafine bubbles) at the desired concentration can be obtained as the storage liquid GL.
    • [Operation and Effects]
  • According to the tank system 200C of the third embodiment, the storage liquid GL in the tank 210B flows from the upstream end PA of the flow path 340 into the flow path 340, passes through the bubble generating unit 341, and is then returned to the tank 210B from the downstream end PB of the flow path 340. Therefore, according to the third embodiment, the storage liquid GL in the tank 210B can be made into a liquid containing bubbles generated by the bubble generating unit 341. Further, by circulating the storage liquid GL through the flow path 340, the bubble concentration of the storage liquid GL can be increased in accordance with the operating time of the bubble generating unit 341.
    • [Modified Example of the Third Embodiment]
  • The tank system 200 according to the third embodiment (referred to as tank system 200D in FIG. 10) may include a liquid inflow unit 350, as shown in FIG. 10. This configuration is referred to as a modified example of the third embodiment. FIG. 10 is a schematic diagram illustrating a configuration of an example of the tank system 200D according to the modified example of the third embodiment.
    • (Liquid Supply Unit)
  • In the modified example of the third embodiment, the liquid inflow unit 350 is not particularly limited as long as it has a structure capable of pouring liquid from an external liquid supply source (not shown) into the tank 210B. The liquid inflow unit 350 includes an inflow flow path 351 that delivers liquid to the tank 210B. Additionally, as needed, an inflow amount control valve 353, which performs opening and closing of the inflow flow path 351, and a pump (not shown) that feeds liquid into the inflow flow path 351 from the external liquid supply source may be provided. The inflow amount control valve 353 may have the same structure as the control valve 22 described in Modified Example 3 of the bubble concentration adjustment device 10. In addition, except for the configuration of the liquid inflow unit 350 and the configurations of the inflow flow rate sensor 352 and the timer 343A described later, the tank system 200D according to the modified example of the third embodiment has the same structure as the tank system 200C according to the third embodiment. Therefore, a detailed description of the other components of the tank system 200D according to the modified example of the third embodiment, except for the configuration of the liquid inflow unit 350 and the configurations of the inflow flow rate sensor 352 and the timer 343A described later, will be omitted.
    • (Inflow Flow Rate Sensor)
  • In the tank system 200D according to the modified example of the third embodiment, it is preferable that an inflow flow rate sensor 352, which detects the flow rate (inflow amount) of the liquid flowing into the tank 210, is provided, as shown in FIG. 10. The inflow flow rate sensor 352 may be of the same type as the first flow rate sensor 31A or the second flow rate sensor 31B shown in Modified Example 5 described in [1. Bubble Concentration Adjustment Device] above.
    • (Timer)
  • In the tank system 200D, the timer 343 (referred to as timer 343A in FIG. 10) defines a time T1 for maintaining the state of the circulation flow rate control valve 342 and a time T2 for maintaining the state of the inflow control valve 353. The times T1 and T2 are determined based on the measurement value of the inflow flow rate sensor 352, the amount of storage liquid GL passing through the bubble generating unit 341, the desired bubble concentration (target concentration of the storage liquid GL), and the desired amount of storage liquid GL (target volume of the storage liquid GL). For example, the difference between the current amount of storage liquid GL and its target volume, and the difference between the current bubble concentration and the target concentration of the storage liquid GL are determined. Based on the measurement value of the inflow flow rate sensor 352, the operating time of the bubble generating unit 341 can be specified as time T1, and the time for introducing liquid into the tank 210 from the liquid inflow unit 350 can be specified as time T2.
  • In the tank system according to the modified example of the third embodiment, it is preferable that the timer 343A is a timer switch configured to change the state of the circulation flow rate control valve 342 to close the flow path 340 upon the lapse of the set time T1, and also to change the state of the inflow control valve 353 to close the inflow flow path 351 upon the elapse of the set time T2. In this case, liquid flows through the interior of the flow path 340 and the inflow flow path 351 only during the times T1 and T2 defined by the timer 343A.
  • According to the tank system 200D of the modified example of the third embodiment, even if the bubble concentration of the storage liquid GL into the tank 210 fluctuates due to the inflow of liquid into the tank 210, it becomes possible to operate the bubble generating unit 341 until the bubble concentration of the storage liquid GL rises to a predetermined value, thereby facilitating adjustment of the bubble concentration of the storage liquid GL.
  • Based on the description in this specification, the following inventions (A1) to (A10) can be understood:
    • (A1) A bubble concentration adjustment device including:
      • a plurality of flow paths for transporting a liquid;
      • a bubble generating unit provided in at least one of the flow paths, the bubble generating unit being capable of generating bubbles having a diameter of less than 1 µm in the liquid; and
      • a flow rate ratio control unit for changing a flow rate ratio of the liquid flowing through the plurality of flow paths so as to allow adjustment of the concentration of the bubbles by mixing the liquid flowing out of the plurality of flow paths.
    • (A2) The bubble concentration adjustment device according to (A1), further including a scale display unit for indicating a concentration of the bubbles,
      wherein the flow rate ratio control unit changes the flow rate ratio in accordance with the concentration of the bubbles indicated on the scale display unit.
    • (A3) The bubble concentration adjustment device according to (A2), further including an inlet for receiving the liquid,
      wherein the flow rate ratio control unit changes the flow rate ratio in accordance with a pressure, a flow velocity, and a flow rate of the liquid received from the inlet.
    • (A4) The bubble concentration adjustment device according to (A3),
      • wherein the inlet is common to the plurality of flow paths, and
      • the flow rate ratio control unit changes the flow rate ratio by changing a distribution ratio of the liquid supplied from the inlet to each of the plurality of flow paths.
    • (A5) The bubble concentration adjustment device according to any one of (A1) to (A4),
      wherein the bubbles are formed by cavitation generated in the liquid.
    • (A6) The bubble concentration adjustment device according to any one of (A1) to (A5), further including a pump for supplying the liquid from the inlet to the plurality of flow paths.
    • (A7) A tank system including:
      • the bubble concentration adjustment device according to any one of (A1) to (A6); and
      • a tank for storing the liquid,
      • wherein the bubble concentration adjustment device and the tank are arranged so that the liquid is supplied to the tank after passing through the bubble concentration adjustment device.
    • (A8) A tank system including:
      • a tank for storing a liquid; and
      • a flow path for transporting the liquid,
      • wherein the flow path includes a bubble generating unit for generating bubbles having a diameter of less than 1 µm in the liquid,
      • both an upstream end and a downstream end of the flow path are connected to the tank, and
      • a timer is provided for determining a time during which the liquid flows through the flow path.
    • (A9) The tank system according to (A7), further including a concentration sensor for measuring a bubble concentration in the liquid stored in the tank, wherein the flow rate ratio control unit is controlled based on a value measured by the concentration sensor.
    • (A10) The tank system according to (A8), wherein the time set in the timer is determined in accordance with a desired concentration of fine bubbles or ultrafine bubbles in the liquid stored in the tank.
    EXPLANATION OF REFERENCE NUMERALS
    • 10 : bubble concentration adjustment device
    • 11 : flow path
    • 11A : first flow path
    • 11B : second flow path
    • 12 : flow rate ratio control unit
    • 13 : bubble generating unit
    • 14 : inlet
    • 15 : receiving flow path
    • 16 : flow rate control member
    • 20 : pipe member
    • 21 : distribution valve
    • 22 : control valve
    • 40 : scale display unit
    • 41 : scale
    • 100 : bubble generating device
    • 200 : tank system
    • 210 : tank
    • 280 : bubble generating unit
    • 341 : bubble generating unit
    • 342 : circulation flow rate control valve
    • 343 : timer

Claims (6)

  1. A bubble concentration adjustment device comprising:
    a plurality of flow paths for transporting a liquid;
    a bubble generating unit provided in at least one of the flow paths, the bubble generating unit being for generating bubbles having a diameter of less than 1 µm in the liquid; and
    a flow rate ratio control unit for changing a flow rate ratio of the liquid flowing through the plurality of flow paths so as to allow adjustment of the concentration of the bubbles by mixing the liquid flowing out of the plurality of flow paths.
  2. The bubble concentration adjustment device according to claim 1,
    further comprising a scale display unit for indicating a concentration of the bubbles,
    wherein the flow rate ratio control unit changes the flow rate ratio in accordance with the concentration of the bubbles indicated on the scale display unit.
  3. The bubble concentration adjustment device according to claim 2,
    further comprising an inlet for receiving the liquid,
    wherein the flow rate ratio control unit changes the flow rate ratio in accordance with at least one of a pressure, a flow velocity, and a flow rate of the liquid received from the inlet.
  4. The bubble concentration adjustment device according to claim 3,
    wherein the inlet is common to the plurality of flow paths, and
    the flow rate ratio control unit changes the flow rate ratio by changing a distribution ratio of the liquid supplied from the inlet to each of the plurality of flow paths.
  5. A tank system comprising:
    the bubble concentration adjustment device according to claim 1; and
    a tank for storing the liquid,
    wherein the bubble concentration adjustment device and the tank are arranged so that the liquid is supplied to the tank after passing through the bubble concentration adjustment device.
  6. A tank system comprising:
    a tank for storing a liquid; and
    a flow path for transporting the liquid,
    wherein the flow path includes a bubble generating unit for generating bubbles having a diameter of less than 1 µm in the liquid,
    both an upstream end and a downstream end of the flow path are connected to the tank, and
    a timer is provided for determining a time during which the liquid flows through the flow path.
EP24784867.4A 2023-04-07 2024-04-01 Bubble concentration adjustment device and tank system Pending EP4691617A1 (en)

Applications Claiming Priority (2)

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JP2023062848A JP7672723B2 (en) 2023-04-07 2023-04-07 Tank System
PCT/JP2024/013417 WO2024210082A1 (en) 2023-04-07 2024-04-01 Bubble concentration adjustment device and tank system

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CN120586692B (en) * 2025-08-04 2025-12-02 佛山市顺德区美的洗涤电器制造有限公司 Aerators, microbubble generating systems and water heaters
CN120586691B (en) * 2025-08-04 2025-12-02 佛山市顺德区美的洗涤电器制造有限公司 Microbubble generation system and water heater
CN120571440B (en) * 2025-08-04 2025-11-18 佛山市顺德区美的洗涤电器制造有限公司 Fluid transport components, microbubble generation systems, and water heaters

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JP2001353102A (en) 2000-04-12 2001-12-25 Toto Ltd Sanitary washing equipment and water storage tank therefor
JP4695610B2 (en) 2007-01-22 2011-06-08 シャープ株式会社 Bioactivation device
JP2016203142A (en) * 2015-04-28 2016-12-08 パナソニックＩｐマネジメント株式会社 Fine bubble control device and fine bubble control method
JP6792103B2 (en) 2016-06-01 2020-11-25 株式会社テックコーポレーション Fine bubble water supply system
JP7204531B2 (en) * 2019-02-28 2023-01-16 キヤノン株式会社 Ultra fine bubble generator
JP7410490B2 (en) * 2019-07-24 2024-01-10 株式会社リスニ Closed land aquaculture equipment and land aquaculture method using the same

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JP2025103049A (en) 2025-07-08
CN120813426A (en) 2025-10-17
JP2024149146A (en) 2024-10-18
WO2024210082A1 (en) 2024-10-10

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