Fine bubble production method, fine bubble production device, and fine bubble production apparatus

Abstract

To provide a fine-bubble production method, a fine-bubble production device, and a fine-bubble production apparatus that are able to produce fine bubbles, which are simple in configuration and high in fine-bubble production efficiency.SOLUTION: This fine-bubble production method is a method for producing a liquid containing fine bubbles of gas from a mixed fluid of gas and liquid by a plurality of swirling mechanisms. Each swirling mechanism of the plurality of swirling mechanisms includes: a swirling chamber having a circular cross section perpendicular to an axis; an inlet hole; and an outlet hole. The production method includes: causing a mixed fluid of liquid and gas to flow into each of the swirling chambers from the inlet hole; producing a swirling flow of the mixed fluid within the swirling chamber; causing the swirling flow to flow out from the outlet hole; and causing the swirling flows flowing out from the respective swirling mechanisms of the plurality of swirling mechanisms to collide with one another to produce a liquid containing fine bubbles.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a fine bubble producing method for producing a liquid containing fine bubbles in the liquid, a fine bubble producing device using said method, and a fine bubble producing apparatus using said fine bubble producing device. [Background technology]

[0002] Bubbles with a diameter of less than 100 μm are called fine bubbles, of which those with a diameter of 1 μm or more but less than 100 μm are called microbubbles, and those with a diameter of less than 1 μm are called ultrafine bubbles. Ultrafine bubbles were previously called nanobubbles, but in 2017 the International Organization for Standardization (ISO) called them ultrafine bubbles. In this specification, they will be called nanobubbles from now on to simplify the explanation and clarify the terminology. These nanobubbles can exist in liquid for a long period of time because the bubble diameter is very small, and it has been confirmed that they can exist in liquid for several months. In addition, because they have special physical properties such as high pressure inside the bubbles and surface electrification, they are expected to be applied to many industries such as the medical field, cleaning field, and water treatment field.

[0003] The main microbubble manufacturing devices used are the swirling flow type and the pressurized dissolution type. As an example of the swirling flow type, a device has been proposed in which a liquid flow supplied from an outer cylinder is made to swirl in an inner cylinder, gas is sucked from a negative pressure cavity in the center of the generated swirling flow, the sucked gas is atomized by the shearing action of the swirling flow, and the gas is discharged as a liquid containing microbubbles (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4652478 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the microbubble-producing device described in Patent Document 1, the inner diameter of the gas-liquid generating tank is the same in the axial direction. Therefore, in order to generate nanobubbles with smaller bubble diameters, it is necessary to increase the rotation speed of the swirling flow to increase the shear force, but this requires an increase in the liquid flow rate to the microbubble-producing device, which increases the pump capacity. In addition, since microbubbles are produced using a single gas-liquid generating tank, there is a limit to how small the diameter of the microbubbles that can be produced can be.

[0006] The present invention has been made in consideration of the above circumstances, and aims to provide a fine bubble production method that can easily produce a liquid containing microbubbles and nanobubbles with small bubble diameters, a fine bubble producing device using the fine bubble production method, and a fine bubble producing apparatus that uses the fine bubble producing device. [Means for solving the problem]

[0007] The fine bubble producing method according to the present invention comprises the steps of: A fine bubble producing method for producing a liquid containing fine bubbles by using a plurality of swirling mechanisms, comprising: Each of the plurality of swirl mechanisms includes a swirl chamber having a circular cross section perpendicular to an axis, an inlet hole, and an outlet hole, An introduction groove connected to the inlet hole is formed on an inner wall of the swirl chamber, A step of introducing a mixture of liquid and gas into the swirl chamber through the inlet; a step of causing the mixed fluid to flow along an inner wall of the swirl chamber by the introduction groove; swirling the mixed fluid in the swirl chamber to generate a swirling flow; causing the swirling flow to flow out of the outlet hole; The fine bubble production method includes a step of producing a liquid containing fine bubbles by colliding swirling flows flowing out from the outlet holes of each of the plurality of swirling mechanisms.

[0009] The fine bubble producing device according to the present invention comprises: A fine bubble producing device for producing a liquid containing fine bubbles from a mixed fluid of liquid and gas, The fine bubble producing device includes a casing having a first supply opening and a second supply opening facing each other and a discharge opening; a first supply nozzle communicating with the first supply opening and supplying the mixed fluid; a second supply nozzle communicating with the second supply opening and supplying the mixed fluid; an exhaust nozzle that is connected to the exhaust opening and that exhausts the liquid containing the fine bubbles; a first swirling mechanism disposed between the first supply opening and the first supply nozzle, into which the mixed fluid flows to generate a swirling flow; a second swirling mechanism disposed between the second supply opening and the second supply nozzle, into which the mixed fluid flows to generate a swirling flow; a collision chamber in which a first swirling flow discharged from the first swirling mechanism and a second swirling flow discharged from the second swirling mechanism collide with each other; a porous plate having an outlet for discharging a liquid containing fine bubbles generated in the collision chamber is provided between the outlet opening and the outlet nozzle; This is a fine bubble producing device, wherein the axis of the first rotating mechanism and the axis of the second rotating mechanism are substantially collinear.

[0010] In addition, the fine bubble producing device according to the present invention is A fine bubble producing device for producing a liquid containing fine bubbles from a mixed fluid of liquid and gas, The fine bubble producing device includes a casing having a supply opening and a discharge opening; a supply nozzle that is in communication with the supply opening and supplies the mixed fluid; an exhaust nozzle that is connected to the exhaust opening and that exhausts the liquid containing the fine bubbles; a first swirling mechanism that is disposed between the discharge opening and the discharge nozzle, and that receives the mixed fluid from a branch supply nozzle branched off from the supply nozzle and generates a swirling flow; a second swirling mechanism disposed between the supply opening and the supply nozzle, into which the mixed fluid flows to generate a swirling flow; a collision chamber in which a first swirling flow discharged from the first swirling mechanism and a second swirling flow discharged from the second swirling mechanism collide with each other; a discharge hole for discharging a liquid containing fine bubbles generated in the collision chamber is provided in a first annular plate portion formed on an outer periphery of the first rotating mechanism; This is a fine bubble producing device, wherein the axis of the first rotating mechanism and the axis of the second rotating mechanism are substantially collinear.

[0011] In addition, in the fine bubble producing device according to the present invention, The first swirl mechanism includes a first swirl chamber having a circular cross section perpendicular to an axis, a first inlet through which the mixed fluid flows into the first swirl chamber, and a first introduction groove formed on an inner wall of the first swirl chamber so as to be connected to the first inlet; a first outlet hole through which the mixed fluid is discharged from the first swirl chamber as a first swirl flow, The second swirl mechanism includes a second swirl chamber having a circular cross section perpendicular to an axis, and a second inlet hole through which the mixed fluid flows into the second swirl chamber. a second introduction groove formed on an inner wall of the second swirl chamber so as to be connected to the second inlet; The fluid mixture may be discharged from the second swirl chamber through a second outlet hole through which the mixed fluid flows as a second swirl flow.

[0013] The fine bubble producing device according to the present invention comprises: A fine bubble producing apparatus for producing a liquid containing fine bubbles using the fine bubble producing device, a supply pump that pumps a fluid; and a first branching portion that branches from a discharge flow path downstream of the supply pump and branches the fluid into a circulation flow path and a supply flow path, a gas-liquid mixer that mixes a gas with the fluid pumped from the supply pump to produce a mixed fluid, and a circulation flow rate control valve that controls a flow rate of the fluid or the mixed fluid to the gas-liquid mixer, a fine bubble producing device to which the mixed fluid is supplied is disposed in the supply flow path, The fine bubble producing device is provided with an exhaust flow path for discharging a liquid containing fine bubbles produced by the fine bubble producing device. Effect of the Invention

[0016] According to the present invention, the mixed fluid that flows into the swirling chamber from the inlet holes of two or more swirling mechanisms becomes a swirling flow and flows out of the outlet holes, and the swirling flows are caused to collide, making it possible to produce fine bubbles with a small bubble diameter and also to produce a liquid containing fine bubbles.

[0017] Furthermore, according to the present invention, the mixed fluid flowing into each swirling chamber is guided into the inlet groove formed in the inner wall of the swirling chamber, flows along the inner wall of the swirling chamber, becomes a swirling flow and flows out of the outlet hole, and each swirling flow is caused to collide, making it possible to produce fine bubbles with a smaller bubble diameter, and also to produce a liquid containing fine bubbles.

[0018] In addition, according to the present invention, a fine bubble manufacturing device can be constructed using a supply nozzle, a casing, a discharge nozzle, and a first rotating mechanism and a second rotating mechanism arranged in the casing, so that the fine bubble manufacturing device can be made small or inexpensively manufactured. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a schematic diagram showing a fine bubble producing device according to an embodiment of the present invention. [Diagram 2] FIG. 1 is a vertical cross-sectional view showing a fine bubble producing device according to an embodiment of the present invention. [Diagram 3] FIG. 3(a) is a vertical cross-sectional view showing a first rotating mechanism of the fine bubble producing device, and FIG. 3(b) is a bottom view taken along the arrow AA in FIG. 3(a). [Figure 4] FIG. 4(a) is a vertical cross-sectional view showing a second rotating mechanism of the fine bubble producing device, and FIG. 4(b) is a bottom view taken along the arrow AA in FIG. 4(a). [Diagram 5] FIG. 2 is a plan view showing a perforated plate disposed in the fine bubble producing device. [Figure 6]FIG. 11 is a vertical cross-sectional view showing a modified first rotating mechanism according to the first modified example of the fine bubble producing device. [Figure 7] FIG. 11 is a vertical cross-sectional view showing another modified example of the first rotating mechanism relating to the first modified example of the fine bubble producing device. [Figure 8] FIG. 11 is a vertical cross-sectional view showing a second modified example of the fine bubble producing device. [Figure 9] FIG. 11 is a vertical cross-sectional view showing a modified example 3 of the fine bubble producing device. [Figure 10] 10(a) is a vertical cross-sectional view showing a first rotating mechanism of a fine bubble producing device according to modified example 3, and FIG. 10(b) is a bottom view taken along the arrow AA in FIG. 10(a). [Figure 11] FIG. 11 is a schematic plan view showing modified example 4 of the fine bubble producing device. [Figure 12] FIG. 1 is a schematic diagram showing a first modified example of a fine bubble producing device. [Figure 13] FIG. 2 is a schematic cross-sectional view showing a layered mixer used in the first modified example of the fine bubble-producing device. [Figure 14] FIG. 1 is a plan view showing elements constituting a layered mixer used in a first modified example of a fine bubble-producing device. [Figure 15] FIG. 15(a) is a plan view showing the first plate (FIG. 15(a)) and the second plate (FIG. 15(a)) constituting the layered mixer used in the first modified example of the fine bubble-producing device. [Figure 16] FIG. 16(a) is a schematic longitudinal cross-sectional view and FIG. 16(b) is a schematic plan view showing how a fluid flows within a stirrer that constitutes a layered mixer used in variant example 1 of a fine bubble-producing apparatus. [Figure 17] FIG. 13 is a schematic diagram showing a second modified example of a fine bubble producing device. [Figure 18] FIG. 13 is a schematic diagram showing a third modified example of the fine bubble producing device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes embodiments of the present invention. Note that these embodiments are merely examples of the present invention, and the present invention is not limited to these embodiments.

[0021] (Fine bubble manufacturing equipment) Fig. 1 shows a fine bubble-producing apparatus 1 according to an embodiment of the present invention. The fine bubble-producing apparatus 1 in this embodiment is equipped with a fine bubble-producing device 2 (2A and 2B in Fig. 1) according to the present invention, and produces bubble water B containing fine air bubbles using raw water W as the liquid and air A as the gas. The raw water W may be ion-exchanged water, tap water, or the like.

[0022] As shown in Fig. 1, the fine bubble production device 1 includes a tank T for storing raw water W, a supply pump 3A for pumping the raw water W from the tank T, and two fine bubble producers 2A and 2B. The raw water W is supplied from the tank T to the supply pump 3A through a suction flow path 311, and the discharge flow path 312 of the supply pump 3A branches into a circulation flow path 313 and a supply flow path 314 at a first branch D1. A gas-liquid mixer 32 and a circulation flow rate control valve 33 are disposed in one of the circulation flow paths 313 branching from the first branch D1. The gas-liquid mixer 32 sucks in air A and mixes it with the raw water W to produce a mixed fluid M, and the produced mixed fluid M is circulated to the suction side of the supply pump 3A. A suction pressure gauge 36 is disposed on the suction side of the supply pump 3A, and a discharge pressure gauge 37 is disposed on the discharge side. A discharge pump 3B for discharging the bubble water B containing the fine bubbles produced by the fine bubble producing devices 2A and 2B to a demand destination is also connected to the tank T. The supply of the raw water W to the supply pump 3A may be from another centrifugal pump (not shown) instead of from the tank T.

[0023] In the gas-liquid mixer 32, the raw water W pressurized by the supply pump 3A is decompressed inside the gas-liquid mixer 32 to generate a low-pressure section, and air A is sucked from the low-pressure section and mixed with the raw water W to generate a mixed fluid M. The flow rate of the raw water W supplied to the gas-liquid mixer 32 or the mixed fluid M circulated to the gas-liquid mixer 32 is adjusted by a circulation flow rate control valve 33 disposed upstream of the gas-liquid mixer 32. The flow rate of the air A sucked from the gas-liquid mixer 32 is adjusted by a gas flow rate control valve 34 disposed in the gas-liquid mixer 32. As described above, the concentration of air A in the mixed fluid M can be adjusted by adjusting the opening degree of the circulation flow rate control valve 33 and the gas flow rate control valve 34. When the supply pump 3A is started, raw water W is supplied to the gas-liquid mixer 32, and then mixed fluid M in which air A and raw water W are mixed is supplied.

[0024] The mixed fluid M circulated to the suction side of the supply pump 3A is merged with the raw water W from the tank T, and is again pressurized by the supply pump 3A and sent to the discharge flow path 312. Then, a part of the mixed fluid M branches off from the first branch part D1 downstream of the discharge flow path 312 of the supply pump 3A, and is again supplied to the gas-liquid mixer 32 disposed in the circulation flow path 313 and mixed with the air A. Therefore, the concentration of air A contained in the mixed fluid M supplied to the fine bubble producers 2A and 2B can be increased.

[0025] On the other hand, the other supply flow path 314 branched from the first branch part D1 downstream of the discharge flow path 312 is further branched into two flow paths, a first branch supply flow path 315 and a second branch supply flow path 316, at a second branch part D2. The first branch supply flow path 315 is branched into two branch flow paths 315a and 315b, and the mixed fluid M is supplied to the fine bubble producing device 2A from the branch flow paths 315a and 315b. The second branch supply flow path 316 is branched into two branch flow paths 316a and 316b, and the mixed fluid M is supplied to the fine bubble producing device 2B from the branch flow paths 316a and 316b. The supply flow rate control valve 35 arranged downstream of the second branch part D2 and upstream of the fine bubble producing device 2B can adjust the flow rate of the mixed fluid M supplied to each of the fine bubble producing devices 2A and 2B.

[0026] The outlets of the fine bubble generators 2A and 2B are connected to discharge flow paths 411 and 412, respectively. A concentration meter 42 for measuring the bubble concentration in the bubble water B discharged from the fine bubble generator 2A is disposed in the discharge flow path 411, and the measurement value of the concentration meter 42 is input to the control mechanism 5. The control mechanism 5 has an input section 51 and an output section 52, and outputs a control signal from the output section 52 based on the measurement value of the concentration meter 42 and the value input to the input section 51, and controls the bubble concentration in the bubble water B to the desired concentration by adjusting the opening of the circulation flow control valve 33 and the gas flow control valve 34, etc.

[0027] (Fine bubble generator) 2 is a schematic diagram of a vertical cross section showing the fine bubble generator 2 (2A, 2B) of this embodiment. In this embodiment, the fine bubble generator 2A and the fine bubble generator 2B are exactly the same, and when simply referred to as the fine bubble generator 2, it refers to the fine bubble generators 2A and 2B. The fine bubble generator 2 has a casing 21 having an approximately T-shaped shape and three openings, and a first swirl mechanism 22 and a second swirl mechanism 23 are disposed in two opposing first supply openings 211 and second supply openings 212 of the casing 21, and a collision chamber 24 is formed between the first swirl mechanism 22 and the second swirl mechanism 23. In order to supply the mixed fluid M to the first swirl mechanism 22 and the second swirl mechanism 23, a branch flow path 315a is connected to the first supply nozzle 25a upstream of the first swirl mechanism 22, and a branch flow path 315b is connected to the second supply nozzle 25b upstream of the second swirl mechanism 23. The first supply opening 211 of the casing 21 and the end of the first supply nozzle 25a are flange-shaped, and a first annular plate portion 223 of the first swivel mechanism 22 is fixed therebetween by bolts and nuts. The second supply opening 212 of the casing 21 and the end of the second supply nozzle 25b are similarly flange-shaped, and a second annular plate portion 233 of the second swivel mechanism 23 is fixed therebetween by bolts and nuts. Note that seal members are provided at appropriate positions between the bolts and nuts to prevent leakage of fluid.

[0028] A perforated plate 26 and a discharge nozzle 27 are disposed downstream of the discharge opening 213 of the casing 21, and the bubble water B containing fine bubbles generated inside the casing 21 passes through the discharge hole 261 and the discharge nozzle 27 provided in the perforated plate 26, and is discharged from the fine bubble producing device 2A to the discharge flow path 411, and from the fine bubble producing device 2B to the discharge flow path 412. The ends of the discharge opening 213 of the casing 21 and the discharge nozzle 27 are flange-shaped, and the perforated plate 26 is fixed therebetween by bolts and nuts, and a seal member is disposed at an appropriate position between the bolts and nuts to prevent leakage of the fluid. The casing 21 may be substantially cross-shaped and equipped with two discharge nozzles 27 and perforated plates 26. For example, in FIG. 2, by further disposing the discharge nozzle 27 and the perforated plate 26 so as to extend downward from the collision chamber 24 in the center of the casing 21, the bubble water B is discharged evenly from the collision chamber 24.

[0029] Fig. 3(a) is a vertical cross-sectional view showing the first swirl mechanism 22 arranged in the fine bubble producing device 2, and Fig. 3(b) is a bottom view taken along the line AA in Fig. 3(a). The first swirl mechanism 22 is formed of a first cylindrical portion 221 having a substantially cylindrical shape at one end and a first protruding portion 222 having a substantially truncated cone shape at the other end. The first cylindrical portion 221 is provided with a first annular plate portion 223 on its outer periphery, and the first annular plate portion 223 is formed with a bolt hole 224 for fixing the first annular plate portion 223 between the first supply opening 211 of the casing 21 and the first supply nozzle 25a, and is fixed between the first supply opening 211 of the casing 21 and the first supply nozzle 25a by a bolt and a nut.

[0030] A first swirl chamber 225 is formed inside the first swirl mechanism 22, and the first swirl chamber 225 is formed by a cylindrical portion 225a having a substantially cylindrical shape and a truncated cone-shaped contraction portion 225b having a substantially triangular cross section in the axial direction. In the first swirl mechanism 22, a first inflow hole 226 is formed penetrating the first cylindrical portion 221 in order to allow the mixed fluid M to flow from the first supply nozzle 25a into the first swirl chamber 225, and a first introduction groove 227 having a semicircular cross section is formed along the wall surface of the cylindrical portion 225a of the first swirl chamber 225 so as to be connected to the outlet opening 226b of the first inflow hole 226 and extend in the same direction. An inlet opening 226a of the first inflow hole 226 is formed on the outer wall of the first cylindrical portion 221, and the mixed fluid M is introduced into the inside of the first swirl chamber 225. A first outlet hole 228 is formed in the protruding portion of the contraction portion 225b. Further, a removable lid 229 is disposed on the end of the cylindrical portion 225a for maintenance and inspection of the inside of the first swirl chamber 225. The lid 229 is fitted and fixed to the inner wall of the first swirl chamber 225 by, for example, a screw mechanism so as to be removable.

[0031] Fig. 4(a) is a vertical cross-sectional view showing the second swivel mechanism 23, and Fig. 4(b) is a bottom view taken along the line AA in Fig. 4(a). Similar to the first swivel mechanism 22, the second swivel mechanism 23 is formed of a second cylindrical portion 231 having a substantially cylindrical shape at one end and a second protruding portion 232 having a substantially truncated cone shape at the other end. The outer periphery of the second cylindrical portion 231 is provided with a second annular plate portion 233, and a bolt hole 234 is formed in the second annular plate portion 233 for fixing the second annular plate portion 233 between the second supply opening 212 of the casing 21 and the second supply nozzle 25b, and the second annular plate portion 233 is fixed between the second supply opening 212 of the casing 21 and the second supply nozzle 25b by a bolt and a nut.

[0032] A second swirl chamber 235 is formed inside the second swirl mechanism 23, and the second swirl chamber 235 is formed by a cylindrical portion 235a having a substantially cylindrical shape and a truncated cone-shaped contraction portion 235b having a substantially triangular cross section in the axial direction. In the second swirl mechanism 23, a second inlet hole 236 is formed penetrating the second cylindrical portion 231 in order to allow the mixed fluid M to flow from the second supply nozzle 25b into the second swirl chamber 235, and a second introduction groove 237 having a semicircular cross section is formed along the wall surface of the cylindrical portion 235a of the second swirl chamber 235 so as to be connected to the outlet opening 236b of the second inlet hole 236 and extend in the same direction. An inlet opening 236a of the second inlet hole 236 is formed on the outer wall of the second cylindrical portion 231, and the mixed fluid M is introduced into the second swirl chamber 235. A second outlet hole 238 is formed in the protruding portion of the contraction portion 235b. Further, a removable lid 239 is disposed on the end of the cylindrical portion 235a for maintenance and inspection of the inside of the second swirl chamber 235. The lid 239 is fitted and fixed to the inner wall of the second swirl chamber 235 by, for example, a screw mechanism so as to be removable.

[0033] As shown in Figures 3(a) and 3(b), the first inlet hole 226 and the first introduction groove 227 in the first swirl mechanism 22 are formed in a tangential direction on a plane perpendicular to the central axis of the first swirl chamber 225, and are formed to form an angle θ with respect to the perpendicular plane of the central axis of the first swirl chamber 225. As shown in Figures 4(a) and 4(b), the second inlet hole 236 and the second introduction groove 237 in the second swirl mechanism 23 are formed in a tangential direction on a plane perpendicular to the central axis of the second swirl chamber 235, and are formed to form an angle θ with respect to the perpendicular plane of the central axis of the second swirl chamber 235. The angle θ formed by the first inlet hole 226 and the first introduction groove 227 with respect to the perpendicular plane of the central axis of the first swirl chamber 225 can be 15° or less, preferably 5° to 15°, and more preferably 8° to 12°. The same is true for the angle θ that the second inlet hole 236 and the second introduction groove 237 form with respect to the plane perpendicular to the central axis of the second swirl chamber 235. Meanwhile, as shown in Figures 3(a) and 4(a), the first inlet hole 226 and the first introduction groove 227 in the first swirl mechanism 22 are formed symmetrically with respect to the second inlet hole 236 and the second introduction groove 237 in the second swirl mechanism 23 with respect to the central axis of each swirl mechanism.

[0034] At the outlet of the discharge opening 213 of the casing 21, which serves as a discharge path, a perforated plate 26 shown in Fig. 5 is disposed, which is further connected to a discharge nozzle 27. The perforated plate 26 has discharge holes 261 (10 discharge holes in this case) for the bubble water B containing the fine bubbles generated in the collision chamber 24 formed in the inner periphery, and a bolt hole 262 formed in the outer periphery. The perforated plate 26, the outer walls of the first and second rotating mechanisms 22 and 23, and the inner wall of the casing 21 form the collision chamber 24. The discharge nozzle 27 of the fine bubble producing device 2A is connected to the discharge flow path 411, and the discharge nozzle 27 of the fine bubble producing device 2B is connected to the discharge flow path 412 by an appropriate method such as a flange or welding, and the bubble water B containing the fine bubbles is returned to the tank T via the discharge flow paths 411, 412.

[0035] In the fine bubble producing device 1 having the fine bubble producers 2A and 2B, when the supply pump 3A is driven by a power source (not shown), the raw water W from the tank T is pressurized by the supply pump 3A and reaches the first branch D1 of the discharge flow path 312. A part of the raw water W that reaches the first branch D1 flows into the circulation flow path 313, and the other part reaches the second branch D2 from the supply flow path 314. The raw water W that flows into the circulation flow path 313 is mixed with the air A sucked by the gas-liquid mixer 32 disposed in the circulation flow path 313 to become a mixed fluid M, which is returned to the suction flow path 311 of the supply pump 3A, merges with the raw water W from the tank T, is pressurized by the supply pump 3A, and flows into the discharge flow path 312 again. On the other hand, the mixed fluid M that reaches the second branch D2 is branched into the first branch supply flow path 315 and the second branch supply flow path 316. The mixed fluid M flowing into the first branch supply flow path 315 is further branched into branch flow paths 315a and 315b, and flows into the fine bubble producing device 2A from the first supply nozzle 25a and the second supply nozzle 25b. The mixed fluid M flowing into the second branch supply flow path 316 is similarly branched into branch flow paths 316a and 316b via the supply flow rate control valve 35, and flows into the fine bubble producing device 2B from the first supply nozzle 25a and the second supply nozzle 25b.

[0036] Immediately after the supply pump 3A is driven, the amount of air A contained in the mixed fluid M is small, so the bubble concentration in the bubble water B produced by the fine bubble producers 2A and 2B is low. Therefore, immediately after the supply pump 3A is driven, the opening of the circulation flow rate control valve 33 may be increased and the discharge pump 3B may not be used, and all of the bubble water B stored in the tank T may be supplied from the supply pump 3A to the fine bubble producers 2A and 2B to circulate within the fine bubble producing apparatus 1, thereby increasing the bubble concentration in the bubble water B.

[0037] The mixed fluid M that flows into the fine bubble producers 2A, 2B from the first supply nozzle 25a and the second supply nozzle 25b of each of the fine bubble producers 2A, 2B then flows into the first swirl chamber 225 from the inlet opening 226a of the first inlet hole 226 that opens on the outer periphery of the first swirl mechanism 22, and flows into the second swirl chamber 235 from the inlet opening 236a of the second inlet hole 236 that opens on the outer periphery of the second swirl mechanism 23. As already explained, the two fine bubble producers 2A, 2B are exactly the same, so the following explanation of this embodiment applies to both the fine bubble producers 2A, 2B.

[0038] The mixed fluid M that has flowed into the first swirl chamber 225 is guided to a first introduction groove 227 having a semicircular cross section formed on the inner wall surface of the first swirl chamber 225 that is connected to the first inlet hole 226, and flows at high speed in the tangential direction along the inner wall of the first swirl chamber 225, thereby becoming a high-speed first swirl flow S1 with the axial direction as its central axis in the first swirl chamber 225. Furthermore, since the cross-sectional area of ​​the plane perpendicular to the central axis of the first swirl chamber 225 gradually decreases at the contracting portion 225b from the cylindrical portion 225a toward the first outlet hole 228, the generated first swirl flow S1 becomes an even higher speed swirl flow and flows out from the first outlet hole 228.

[0039] Meanwhile, the mixed fluid M that has flowed into the second swirl chamber 235 is also guided to the second introduction groove 237, which has a semicircular cross section and is formed on the inner wall surface of the second swirl chamber 235 connected to the second inlet hole 236, and flows at high speed in the tangential direction along the inner wall of the second swirl chamber 235, becoming a high-speed second swirl flow S2 with the axial direction as the central axis in the second swirl chamber 235. Furthermore, similar to the first swirl chamber 225, the cross-sectional area of ​​the plane perpendicular to the central axis of the second swirl chamber 235 also gradually decreases at the contracting portion 235b from the cylindrical portion 235a toward the second outlet hole 238, so that the generated second swirl flow S2 flows out from the second outlet hole 238 as an even higher speed swirl flow.

[0040] As shown in Figures 3(a) and 4(a), the first inlet hole 226 and the first introduction groove 227 in the first swirling mechanism 22 are formed symmetrically with respect to the central axis of each swirling mechanism with respect to the second inlet hole 236 and the second introduction groove 237 in the second swirling mechanism 23, so that the first swirling flow S1 formed by the first swirling mechanism 22 swirls in the opposite direction to the second swirling flow S2 formed by the second swirling mechanism 23.

[0041] The first inlet hole 226 and the first introduction groove 227 of the first swirl mechanism 22 are formed so as to be tangential to a plane perpendicular to the central axis of the first swirl mechanism 22 and to form an angle θ with respect to the plane perpendicular to the central axis. Therefore, the mixed fluid M that flows into the first swirl chamber 225 at an angle θ is guided to the first introduction groove 227 and can reliably generate the first swirl flow S1. Similarly, the second inlet hole 236 and the second introduction groove 237 of the second swirl mechanism 23 are formed so as to be tangential to a plane perpendicular to the central axis of the second swirl mechanism 23 and to form an angle θ with respect to the plane perpendicular to the central axis. Therefore, the mixed fluid M that flows into the second swirl chamber 235 at an angle θ is guided to the second introduction groove 237 and can reliably generate the second swirl flow S2.

[0042] Since the first outlet hole 228 of the first swirling mechanism 22 and the second outlet hole 238 of the second swirling mechanism 23 are formed with small diameters, the first swirling flow S1 and the second swirling flow S2 become high-speed jets and flow out into the collision chamber 24. Furthermore, since the first swirling flow S1 and the second swirling flow S2 swirl in the opposite direction to each other, they collide violently with a large impact force in the collision chamber 24. As a result, the air A contained in the first swirling flow S1 and the second swirling flow S2 generated from the mixed fluid M is effectively atomized, and bubble water B containing fine air bubbles is generated.

[0043] The bubble water B containing the fine bubbles generated in the collision chamber 24 reaches the perforated plate 26 arranged at the outlet of the discharge opening 213 of the casing 21, passes through the discharge hole 261 formed in the perforated plate 26 shown in Fig. 5, and is discharged from the discharge nozzle 27. The multiple discharge holes 261 (10 discharge holes in this case) formed in the perforated plate 26 are for maintaining the inside of the collision chamber 24 at a predetermined pressure, and the number and inner diameter of the discharge holes 261 can be appropriately changed depending on the size, design conditions, operating conditions, etc. of the fine bubble producing device 2. The bubble water B discharged from the discharge nozzle 27 of the fine bubble producing devices 2A and 2B flows into the tank T from the discharge flow paths 411 and 412, and a part of it is discharged to the demand destination by the discharge pump 3B together with the raw material water W supplied to the tank T, and the remainder is supplied again to the fine bubble producing devices 2A and 2B by the supply pump 3A.

[0044] In this fine bubble producing apparatus 1, the flow rate of the mixed fluid M supplied to each of the fine bubble producing devices 2A and 2B can be adjusted by the supply flow rate adjustment valve 35. For example, by increasing the aperture of the supply flow rate adjustment valve 35, the flow rate of the mixed fluid M supplied to the fine bubble producing device 2A decreases, and the flow rate of the mixed fluid M supplied to the fine bubble producing device 2B increases. Conversely, by decreasing the aperture of the supply flow rate adjustment valve 35, the flow rate of the mixed fluid M supplied to the fine bubble producing device 2A increases, and the flow rate of the mixed fluid M supplied to the fine bubble producing device 2B decreases. By these operations, the bubble diameter, bubble concentration, and bubble diameter distribution of the nanobubbles and microbubbles in the bubble water B produced from each of the fine bubble producing devices 2A and 2B can be controlled.

[0045] The bubble water B discharged into the tank T is again supplied to the fine bubble producing devices 2A, 2B by the supply pump 3A and circulated, which makes it possible to further refine the bubble diameter of the fine bubbles contained in the bubble water B. This makes it possible to increase the concentration of nanobubbles contained in the bubble water B and increase the number of bubbles.

[0046] The control mechanism 5 is connected to an input unit 51 into which the bubble diameter and bubble concentration in the bubble water B discharged from the fine bubble producing device 2A and the set value of the flow rate of the bubble water B are input. Then, based on the measurement value of the concentration meter 42, the output unit 52 controls the aperture of the circulation flow rate control valve 33 for the mixed fluid M, the aperture of the gas flow rate control valve 34, and the discharge flow rate of the supply pump 3A so that the bubble concentration in the bubble water B from the fine bubble producing device 2A becomes the set concentration input to the input unit 51.

[0047] For example, if the bubble concentration in the bubbly water B measured by the concentration meter 42 is lower than the target value, the opening of the circulation flow control valve 33 and the gas flow control valve 34 can be increased to increase the flow rate of the mixed fluid M to the circulation flow path 313 and the flow rate of the air A sucked in from the gas-liquid mixer 32. This reduces the flow rate of the mixed fluid M supplied to the fine bubble producers 2A and 2B, and increases the amount of air A contained in the mixed fluid M. As a result, the flow rate of the generated bubble water B decreases, the bubble concentration in the bubble water B increases, and the bubble diameter becomes larger and distributed over a wider range.

[0048] In the above, if it is desired to increase the bubble concentration in the bubble water B and reduce the bubble diameter so as to distribute the bubbles over a narrow range without decreasing the flow rate of the generated bubble water B, the discharge flow rate of the supply pump 3A may be increased. In this case, the aperture of the gas flow rate control valve 34 may be made to follow the aperture of the circulation flow rate control valve 33, so that air A is supplied to the circulation flow path 313 at a predetermined flow rate ratio with respect to the flow rate of the mixed fluid M.

[0049] On the other hand, when the bubble concentration measured by the concentration meter 42 is higher than the target value, the opening of the circulation flow rate control valve 33 and the gas flow rate control valve 34 can be reduced to reduce the flow rate of the mixed fluid M into the circulation flow path 313 and the flow rate of the air A sucked in from the gas-liquid mixer 32. This increases the flow rate of the mixed fluid M supplied to the fine bubble producing devices 2A, 2B and reduces the amount of air A contained in the mixed fluid M. As a result, the flow rate of the generated bubble water B increases, the bubble concentration in the bubble water B decreases, and the bubble diameter becomes smaller and distributed over a narrow range.

[0050] Furthermore, by adjusting only the aperture of the gas flow rate control valve 34 of the gas-liquid mixer 32 with the control mechanism 5, it is possible to adjust the bubble size distribution in the bubble water B discharged from the fine bubble producers 2A, 2B. For example, while maintaining the circulation flow rate control valve 33 at a predetermined aperture, increasing the aperture of the gas flow rate control valve 34 increases the proportion of bubbles with large diameters, whereas decreasing the aperture of the gas flow rate control valve 34 decreases the proportion of bubbles with large diameters and increases the proportion of bubbles with small diameters.

[0051] As described above, the control mechanism 5 adjusts the aperture of the circulation flow rate control valve 33, the aperture of the gas flow rate control valve 34, and the discharge flow rate of the supply pump 3A via the output unit 52 based on the bubble diameter, bubble concentration, and flow rate of bubble water B input to the input unit 51. Then, bubble water B containing fine bubbles with the bubble concentration, bubble diameter, and set flow rate input to the input unit 51 can be stably discharged from the fine bubble producing device 2A.

[0052] When operating the fine bubble-producing apparatus 1, the supply flow rate control valve 35 may be fully closed to produce bubble water B containing fine bubbles only using the fine bubble producer 2A. Even in this manner, it is possible to obtain bubble water B containing fine bubbles of the desired bubble diameter, bubble concentration, and flow rate by adjusting the discharge flow rate of the supply pump 3A and the apertures of the circulation flow rate control valve 33 and the gas flow rate control valve 34.

[0053] In order to make it easier to control the fine bubble-producing apparatus 1, a supply flow rate control valve 35 may be provided at both inlets of the fine bubble-producing devices 2A and 2B so that the flow rate of the mixed fluid M to each of the fine bubble-producing devices 2A and 2B can be adjusted independently. Furthermore, in order to increase the flow rate of the bubble water B containing fine bubbles produced by the fine bubble-producing apparatus 1, three or more branch supply flow paths may be branched from the second branch part D2, and a fine bubble-producing device 2 may be provided at each branch supply flow path. In this case, a supply flow rate control valve 35 may be provided at each branch supply flow path, and each fine bubble-producing device 2 may be discharged into the tank T through its own discharge flow path, or may be discharged into the tank T together through a single discharge flow path.

[0054] (Fine bubble generator variant 1) FIG. 6 is a vertical cross-sectional view showing the first swirling mechanism 22a according to the first modification of the fine bubble producing device. In the fine bubble producing device 2 of the present invention, as shown in FIG. 3(a), the contraction part 225b of the first swirling chamber 225 is a truncated cone shape having a substantially triangular cross section in the axial direction, but as shown in this modification, the contraction part 225c may be a trumpet tube shape. Even if the contraction part 225c is a trumpet tube shape, the cross-sectional area of ​​the vertical plane to the central axis of the first swirling chamber 225 gradually decreases toward the first outlet hole 228 in the contraction part 225c, so that the first swirling flow S1 generated in the cylindrical part 225a becomes a swirling flow at a higher speed and flows out from the first outlet hole 228. Similarly, the second swirling chamber 235 of the second swirling mechanism 23a may also have a trumpet tube shape contraction part 235c as shown in FIG. 6.

[0055] Furthermore, in this first modification, the first swirl mechanism 22b may have a contraction section 225d having a semi-ellipsoidal shape as shown in Fig. 7. Even if the contraction section 225d has a semi-ellipsoidal shape, the first swirl flow S1 generated in the cylindrical section 225a becomes a high-speed swirl flow and flows out from the first outlet hole 228 because the cross-sectional area of ​​the plane perpendicular to the central axis of the first swirl chamber 225 gradually decreases in the contraction section 225d toward the first outlet hole 228, so that the first swirl flow S1 flows out from the first outlet hole 228. Similarly, the second swirl chamber 235 of the second swirl mechanism 23b may have a contraction section 235d having a semi-ellipsoidal shape as shown in Fig. 7.

[0056] (Fine bubble generator variant 2) 8 is a schematic diagram showing a fine bubble producing device 2C according to the modified example 2. In the fine bubble producing device 2C, the first supply nozzle 25a and the second supply nozzle 25b for supplying the mixed fluid M to the first swirling mechanism 22 and the second swirling mechanism 23 are directly connected to the inlet opening 236a of the first inlet 226 and the inlet opening 236a of the second inlet 236, respectively, as the first supply nozzle 25c and the second supply nozzle 25d. Even in this case, the mixed fluid M is supplied to the inside of the first swirling chamber 225 of the first swirling mechanism 22 and the second swirling chamber 235 of the second swirling mechanism 23, and the first swirling flow S1 and the second swirling flow S2 are generated. By forming the first supply nozzle 25c and the second supply nozzle 25d in the shape as described above, it is not necessary to connect the branch flow paths 315a and 315b by flanges, so that the fine bubble producing device 2C is easy to handle.

[0057] (Fine bubble generator variation 3) Fig. 9 is a schematic diagram showing a fine bubble producing device 2D according to the modified example 3, Fig. 10(a) is a vertical cross-sectional view of the first swirling mechanism 22c used in the fine bubble producing device 2D, and Fig. 10(b) is a bottom view from the arrow AA in Fig. 10(a). The casing 21a in the fine bubble producing device 2D has only two openings, the supply opening 211a and the discharge opening 213a, the second swirling mechanism 23 is disposed between the supply opening 211a and the supply nozzle 25e, and the first swirling mechanism 22c is disposed between the discharge opening 213a and the discharge nozzle 27a. In the fine bubble producing devices 2A and 2B of the embodiment, the mixed fluid M is supplied from two first supply nozzles 25a and second supply nozzles 25b, but in this modified example 3, the mixed fluid M is supplied to the fine bubble producing device 2D only from the supply nozzle 25e connected to the supply opening 211a. That is, the mixed fluid M is supplied to the second swirling chamber 235 of the second swirling mechanism 23 from the inlet opening 236a of the second inlet 236 opening on the outer periphery of the second cylindrical portion 231, and the mixed fluid M is supplied to the first swirling chamber 225 of the first swirling mechanism 22c from the inlet opening 226a of the first inlet 226 opening on the outer periphery of the first cylindrical portion 221 via the branched supply nozzle 25f branched from the supply nozzle 25e. The bubble water B generated in the collision chamber 24a passes through the discharge hole 261a (see Fig. 10(a) and Fig. 10(b)) formed in the first annular plate portion 223a of the first swirling mechanism 22c and is discharged from the discharge nozzle 27a communicating with the discharge opening 213a of the casing 21a. In such a fine bubble producing device 2D, the supply nozzle 25e and the discharge nozzle 27a are located in the same direction, so that the connection to the piping in the fine bubble producing device 1 is easy and the handling is easy.

[0058] (Fine bubble generator variant 4) Fig. 11 is a schematic diagram showing a fourth modification of the fine bubble producing device according to the present invention. In the fine bubble producing device 2E in the fourth modification, the mixed fluid M is supplied from the supply nozzle 25 to the four swirl mechanisms 22d, 22e, 22f, and 22g, and the generated bubble water B is discharged from the discharge nozzle 27 (not shown) provided vertically above and / or below the position where the axes of the swirl mechanisms 22d, 22e, 22f, and 22g intersect. By making the extension lines of the axes of the swirl mechanisms 22d, 22e, 22f, and 22g intersect at the same position, the swirl flows S flowing out from the swirl mechanisms 22d, 22e, 22f, and 22g can be collided at the same position, so that the bubbles in the generated bubble water B can be made fine. By increasing the number of swirl mechanisms as shown in Fig. 11, the flow rate of the generated bubble water B can be increased. In addition, it is desirable that the distance from the position where the axes of the rotation mechanisms 22d, 22e, 22f, and 22g intersect to each rotation mechanism be approximately equal. Furthermore, the number of rotation mechanisms 22 is not limited to four, and may be three, or five or more.

[0059] (Variation 1 of the fine bubble manufacturing device) FIG. 12 is a schematic diagram showing a fine bubble-producing apparatus 1A according to the first modification. In the fine bubble-producing apparatus 1A, a laminated mixer 6 shown in FIG. 13 is disposed downstream of a gas-liquid mixer 32, and the air A contained in the mixed fluid M is further finely divided in a circulation flow path 313. The laminated mixer 6 is, for example, a stacked body 62 in which a plurality of elements 61a and 61b shown in FIG. 14(a) and FIG. 14(b) are stacked inside a short tube 69, and a stirrer 65 formed by a first plate 63 shown in FIG. 15(a) and a second plate 64 shown in FIG. 15(b) are arranged opposite each other with the laminated body 62 in between. The elements 61a and 61b, the first plate 63, and the second plate 64 forming the stirrer 65 are locked by a bolt 66 and a nut 67.

[0060] The elements 61a and 61b each have a central hole 613 for a bolt 66 and a plurality of through holes 612 separated by a partition wall 611, and the second plate 64 has an opening 642 communicating with at least one of the through holes 612 of the elements 61a and 61b. In the stack 62, the elements 61a and 61b are arranged such that a part or all of the through holes 612 partially overlap with the through holes 612 of the adjacent elements 61a and 61b at a shifted position, and communicate with the through holes 612 of the adjacent elements 61a and 61b so that a fluid can flow between them. Therefore, as shown in FIG. 16, the fluid that has flowed into the stack 62 flows in a manner that it is divided and merged in the stacking direction (see FIG. 16(a)) and the extension direction (see FIG. 16(b)) of the elements 61a and 61b. In order to facilitate overlapping, the elements 61a and 61b are formed with a notch 614 for identifying the overlapping position (see FIG. 14).

[0061] As shown in FIG. 15(a), the first plate 63 is a circular plate having only a central hole 631 for the bolt 66. As shown in FIG. 15(b), the second plate 64 has a central hole 641 for the bolt 66 and two substantially C-shaped openings 642 in the center for passing the mixed fluid M. The outer diameter of the first plate 63 is smaller than that of the second plate 64 and the elements 61a and 61b, and the outer diameter of the second plate 64 is substantially the same as that of the elements 61a and 61b. Therefore, as shown in FIG. 13, the agitator 65 has the through holes 612 of the elements 61a and 61b exposed outside the outer periphery of the first plate 63, and the through holes 612 of the elements 61a and 61b exposed at the opening 642 in the center of the second plate 64.

[0062] The agitator 65 having the above basic configuration has a configuration of the first plate 63-stack 62-second plate 64-stack 62-first plate 63 from the upstream side, as shown in FIG. 13. The mixed fluid M supplied to the stacked mixer 6 having such an agitator 65 flows into the stack 62 on the upstream side through the through hole 612 of the element 61a exposed on the outside of the outer periphery of the first plate 63 on the upstream side, flows through the inside of the stack 62, and then passes through the opening 642 in the center of the second plate 64 and flows into the stack 62 on the downstream side. The mixed fluid M that flows into the stack 62 on the downstream side flows through the inside of the stack 62, and then flows out of the through hole 612 of the element 61b exposed on the outside of the outer periphery of the first plate 63 on the downstream side. Then, when flowing through the two stacks 62, the mixed fluid M flows while being subjected to the actions of division, merging, shearing, vortex flow, etc., so that the air A in the mixed fluid M can be further finely divided.

[0063] As a result, the air A in the mixed fluid M that flows in from the gas-liquid mixer 32 can be made even finer by the layered mixer 6, and the bubble diameter in the bubbly water B produced by the fine bubble producers 2A and 2B can be made even smaller. Note that in the layered mixer 6 in Fig. 13, a stepped portion 691 is provided on the inner wall of the short tube 69 and a coil spring 68 is provided inside the short tube 69 to prevent the agitator 65 from jumping out, but other means may be used to prevent the agitator 65 from jumping out.

[0064] (Variation 2 of the fine bubble producing device) 17 is a schematic diagram showing a fine bubble-producing apparatus 1B according to Modification 2. The control mechanism 5 in the fine bubble-producing apparatus 1B is provided with a data table 53 in which the flow rate of the bubbly water B discharged from the fine bubble-producing device 2A, the bubble diameter and bubble concentration in the bubbly water B are stored in correspondence with the power load of the supply pump 3A, the aperture of the circulation flow rate control valve 33, the aperture of the gas flow rate control valve 34, the aperture of the supply flow rate control valve 35, and the measured values ​​of the suction pressure gauge 36 and the discharge pressure gauge 37. The power load of the supply pump 3A can be determined based on the value of the current supplied to the supply pump 3A.

[0065] In this modification 2, when operating the fine bubble manufacturing device 1B shown in Fig. 17, the flow rate of the bubble water B discharged from the fine bubble manufacturing device 2A, the bubble diameter and bubble concentration in the bubble water B are input from the input unit 51. Then, the control mechanism 5 refers to the data table 53 and sets the power load of the supply pump 3A and the aperture of the circulation flow rate control valve 33 and the gas flow rate control valve 34 as target values ​​so that the flow rate, bubble diameter and bubble concentration of the input bubble water B are achieved. Next, the control mechanism 5 adjusts the set power load of the supply pump 3A and the aperture of the circulation flow rate control valve 33 and the gas flow rate control valve 34 so that they become the target values. The control mechanism 5 can also adjust the aperture of the supply flow rate control valve 35 to adjust the flow rate, bubble diameter and bubble concentration of the input bubble water B. Furthermore, the control mechanism 5 can refer to a data table 53 based on the measured values ​​of the suction pressure gauge 36 and the discharge pressure gauge 37, and adjust the power load of the supply pump 3A, the circulation flow rate control valve 33, and the gas flow rate control valve 34. Note that, in order to respond to changes in water temperature, the temperature of the mixed fluid M may be measured and incorporated into the data table 53 as data for control.

[0066] In this second modification, the control mechanism 5 sets the power load of the supply pump 3A and the apertures of the circulation flow rate control valve 33 and the gas flow rate control valve 34 by referring to a data table 53 based on the flow rate of bubble water B discharged from the fine bubble manufacturing device 2A and the bubble diameter and bubble concentration in the bubble water B, but the power load of the supply pump 3A and the apertures of the circulation flow rate control valve 33 and the gas flow rate control valve 34 may also be set using a function with the bubble diameter, bubble concentration, and the flow rate of bubble water B as parameters. Also, adjustment based on the measured values ​​of the suction pressure gauge 36 and the discharge pressure gauge 37 does not necessarily have to be performed.

[0067] (Variation 3 of the fine bubble production device) 18 is a schematic diagram showing a fine bubble-producing apparatus 1C according to Modification 3. The fine bubble-producing apparatus 1C is equipped with only one fine bubble-producing device 2A. Even with the fine bubble-producing apparatus 1C equipped with only the fine bubble-producing device 2A, it is possible to produce bubble water B containing the desired fine bubbles by appropriately adjusting the load of the supply pump 3A and the opening of the circulation flow rate control valve 33 and the gas flow rate control valve 34. In this Modification 3, a supply flow rate control valve 35 may be provided at the inlet of the fine bubble-producing device 2A to further adjust the bubble diameter, bubble concentration, and flow rate of the bubble water B.

[0068] In the above embodiment, water is used as the liquid and air is used as the gas, but the liquid may be slightly acidic electrolyzed water, physiological saline, or any other type of liquid, and the gas may be hydrogen, oxygen, ozone, nitrogen, carbon dioxide, or any other type of gas.

[0069] The fine bubbles produced by the fine bubble producing device 1, the fine bubble producing device 2, and the fine bubble producing method according to the present invention can be used for various applications. For example, in the medical and medical-related industries, oral administration of oxygen nanobubble water with a mode particle size of 58 nm has been shown to improve the therapeutic effects of tumor radiation therapy and chemotherapy (Joshua Owen, et al., December 30, 2016, https: / / doi.org / 10.1371 / journal.pone.0168088), and in clinical applications of genes and nucleic acid medicines, the possibility of enhancing the delivery effect to target tissues and target cells by using microbubbles or nanobubbles in combination with ultrasound has been shown (Yoko Endo-Takahashi, et al., Drug Delivery System, 34-2, 116-123, (2019)), and the fine bubbles can be used for these applications. For these applications, it is preferable to use raw water W with few impurities, such as pure water, ultrapure water, purified water, distilled water, and Milli-Q water (registered trademark).

[0070] Furthermore, the fine bubble-containing liquid produced by the fine bubble-producing apparatus 1, fine bubble-producing device 2, and method for producing a liquid containing fine bubbles according to the present invention can be used in the fisheries industry for fish, oysters, etc., and in the livestock industry, such as pig farming and poultry farming, for the purposes of promoting growth, maintaining water quality, purifying wastewater, etc.

[0071] Furthermore, the fine bubble-producing device 1, the fine bubble-producing device 2, and the liquid containing fine bubbles produced by the fine bubble production method according to the present invention can be used for various purposes. For example, they can be used as components of various processes and products in industries such as the environment-related industry, agriculture and livestock industry, food-related industry, electronics industry, medical and medical-related industry, energy-related industry, daily necessities-related industry, paper industry, shipbuilding industry, and machine manufacturing industry. Note that the present invention is not limited to the above embodiments or examples. [Explanation of symbols]

[0072] 1,1A,1B,1C Fine bubble manufacturing equipment 2,2A,2B,2C,2D,2E Fine bubble generator 21,21a Casing 211 (of casing 21) first supply opening 211a (of casing 21a) supply opening 212 (of casing 21) second supply opening 213 (of casing 21) exhaust opening 213a (of casing 21a) discharge opening 22, 22a, 22b, 22c, 22d, 22e, 22f, 22g First rotating mechanism 221 First cylindrical section 222 1st protrusion 223, 223a First annular plate 224 Bolt Hole 225 1st turning room 225a (First swirl chamber) cylindrical part 225b, 225c, 225d (First turning chamber) reduction section 226 1st inflow hole 226a (first inlet) inlet opening 226b (first inlet) outlet opening 227 1st introduction groove 228 1st outflow hole 229 Lid 23, 23a, 23b, 23c Second rotating mechanism 231 Second cylindrical section 232 Second protrusion 233 Second annular plate 234 Bolt Hole 235 2nd turning room 235a (of the second swirl chamber) cylindrical part 235b, 235c, 235d (of the second swirl chamber) 236 2nd inflow hole 236a (second inlet) inlet opening 236b (second inlet) outlet opening 237 2nd introduction groove 238 2nd outflow hole 239 Lid 24,24a Collision chamber 25,25e Supply nozzle 25a, 25c First supply nozzle 25b, 25d Second supply nozzle 25f Branching Supply Nozzle 26 Perforated plate 261,261a Discharge hole 262 Bolt Hole 27,27a Discharge nozzle 3A Supply Pump 3B Discharge Pump 311 Suction passage 312 Discharge flow path 313 Circulation Channel 314 Supply Channel 315 First branch supply channel 315a, 315b (of the first branch supply flow path) 316 Second branch supply channel 316a, 316b (second branch supply flow path) branch flow path 32 Gas-liquid mixer 33 Circulation flow control valve 34 Gas flow control valve 35 Supply flow control valve 36 Suction pressure gauge 37 Discharge pressure gauge 411, 412 Discharge flow path 42 Concentration meter 5 Control mechanism 51 Input section 52 Output section 53 Data table 6 Stacked mixer A Air B Bubble water D1 First branch section D2 Second branch section M Mixed fluid S Swirling flow S1 First swirling flow S2 Second swirling flow T Tank W Raw water

Claims

1. A fine bubble producing method for producing a liquid containing fine bubbles by using a plurality of swirling mechanisms, comprising: Each of the plurality of swirl mechanisms includes a swirl chamber having a circular cross section perpendicular to an axis, an inlet hole, and an outlet hole, An introduction groove connected to the inlet hole is formed on an inner wall of the swirl chamber, A step of introducing a mixture of liquid and gas into the swirl chamber through the inlet; a step of causing the mixed fluid to flow along an inner wall of the swirl chamber by the introduction groove; swirling the mixed fluid in the swirl chamber to generate a swirling flow; causing the swirling flow to flow out of the outlet hole; A method for producing fine bubbles, comprising a step of producing a liquid containing fine bubbles by colliding swirling flows flowing out from the outlet holes of each of the plurality of swirling mechanisms.

2. In the fine bubble producing method according to claim 1, The axes of the rotating mechanisms are substantially collinear, Or a fine bubble producing method, wherein the axes of each of the rotating mechanisms intersect at approximately the same position.

3. In the fine bubble producing method according to claim 1 or 2, A fine bubble producing method, wherein the cross-sectional area of ​​the swirling chamber in a direction perpendicular to the axis of each swirling mechanism decreases toward the outflow hole.

4. In the fine bubble producing method according to any one of claims 1 to 3, A fine bubble producing method, wherein the inlet hole and the introduction groove have an inclination angle with respect to a plane perpendicular to the axis of the swirling mechanism.

5. In the fine bubble producing method according to any one of claims 1 to 4, a collision chamber in which swirling flows flowing out from the outlet holes of the plurality of swirling mechanisms collide with each other, A method for producing fine bubbles, wherein a perforated plate for maintaining the inside of the collision chamber at a predetermined pressure is provided in a discharge path for discharging the liquid containing the fine bubbles.

6. A fine bubble producing device for producing a liquid containing fine bubbles from a mixed fluid of liquid and gas, The fine bubble producing device includes a casing having a first supply opening and a second supply opening facing each other and a discharge opening; a first supply nozzle communicating with the first supply opening and supplying the mixed fluid; a second supply nozzle communicating with the second supply opening and supplying the mixed fluid; an exhaust nozzle that is connected to the exhaust opening and that exhausts the liquid containing the fine bubbles; a first swirling mechanism disposed between the first supply opening and the first supply nozzle, into which the mixed fluid flows to generate a swirling flow; a second swirling mechanism disposed between the second supply opening and the second supply nozzle, into which the mixed fluid flows to generate a swirling flow; a collision chamber in which a first swirling flow flowing out from the first swirling mechanism and a second swirling flow flowing out from the second swirling mechanism collide with each other; a porous plate having an outlet for discharging a liquid containing fine bubbles generated in the collision chamber is provided between the outlet opening and the outlet nozzle; A fine bubble producing device, wherein the axis of the first rotating mechanism and the axis of the second rotating mechanism are approximately collinear.

7. A fine bubble producing device for producing a liquid containing fine bubbles from a mixed fluid of liquid and gas, The fine bubble producing device includes a casing having a supply opening and a discharge opening; a supply nozzle that is in communication with the supply opening and supplies the mixed fluid; an exhaust nozzle that is connected to the exhaust opening and that exhausts the liquid containing the fine bubbles; a first swirling mechanism that is disposed between the discharge opening and the discharge nozzle, and that receives the mixed fluid from a branch supply nozzle branched off from the supply nozzle and generates a swirling flow; a second swirling mechanism disposed between the supply opening and the supply nozzle, the second swirling mechanism receiving the mixed fluid and generating a swirling flow; a collision chamber in which a first swirling flow flowing out from the first swirling mechanism and a second swirling flow flowing out from the second swirling mechanism collide with each other; a discharge hole for discharging a liquid containing fine bubbles generated in the collision chamber is provided in a first annular plate portion formed on an outer periphery of the first rotating mechanism; A fine bubble producing device, wherein the axis of the first rotating mechanism and the axis of the second rotating mechanism are approximately collinear.

8. The fine bubble producing device according to claim 6 or 7, the first swirl mechanism comprises a first swirl chamber having a circular cross section perpendicular to an axis, a first inlet hole through which the mixed fluid flows into the first swirl chamber, a first introduction groove formed in an inner wall of the first swirl chamber so as to be connected to the first inlet hole, and a first outlet hole through which the mixed fluid flows out of the first swirl chamber as a first swirl flow, The second swirling mechanism comprises a second swirling chamber having a circular cross section perpendicular to the axis, a second inlet hole for allowing the mixed fluid to flow into the second swirling chamber, a second introduction groove formed in the inner wall of the second swirling chamber so as to connect to the second inlet hole, and a second outlet hole for allowing the mixed fluid to flow out of the second swirling chamber as a second swirling flow.

9. The fine bubble producing device according to claim 8, A cross-sectional area of ​​the first swirl chamber in a direction perpendicular to an axis of the first swirl mechanism is reduced toward the first outlet hole, A fine bubble producing device, wherein the cross-sectional area of ​​the second swirling chamber in a direction perpendicular to the axis of the second swirling mechanism decreases toward the second outlet hole.

10. The fine bubble producing device according to claim 8, the first inlet hole and the first introduction groove have an inclination angle with respect to a plane perpendicular to an axis of the first rotating mechanism, A fine bubble producing device, wherein the second inlet hole and the second introduction groove have an inclination angle with respect to a plane perpendicular to the axis of the second rotating mechanism.

11. A fine bubble producing apparatus for producing a liquid containing fine bubbles using the fine bubble producing device according to any one of claims 6 to 10, a supply pump that pumps a fluid; and a first branching portion that branches from a discharge flow path downstream of the supply pump and branches the fluid into a circulation flow path and a supply flow path, a gas-liquid mixer that mixes a gas with the fluid pumped from the supply pump to produce a mixed fluid, and a circulation flow rate control valve that controls a flow rate of the fluid or the mixed fluid to the gas-liquid mixer, a fine bubble producing device to which the mixed fluid is supplied is disposed in the supply flow path, A fine bubble producing device comprising: a discharge flow path for discharging a liquid containing fine bubbles produced by the fine bubble producing device.

Images