JP2016036775A - Fine bubble generator and method for generation of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a particle size of fine bubble having a diameter of a nanometer order so as to be small and constant, and stably generate the fine bubble with a good efficiency.SOLUTION: A fine bubble generator blends air 6 supplied from a gas supply device into water 5 discharged from a pump 10, and generates gas-liquid mixed water 7 including foam-like bubbles. The gas-liquid mixed water 7 is delivered and injected into a fine bubble generating part 30 thereby making a bubble into a fine bubble. Fine bubbling generates cavitation which occurs generation and collapse of bubbles when the mixed water is injected, the injected gas-liquid mixed water generates an eddy current which swirls in a flat space while oscillating, and the bubbles are made into fine bubbles by energy generated due to collapse of the bubbles and a shear force generated by the eddy current. Fine bubble containing water 8, which contains the refined fine bubbles, is delivered to a jet nozzle 60 thereby generating cavitation, and the fine bubbles are refined again thereby making fine bubble containing water 9 which contains stable fine bubbles.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fine bubble generating apparatus for generating fine bubbles and a method for generating the same. More specifically, the present invention relates to a microbubble generator for generating microbubbles (nanobubbles) having a diameter on the order of nanometers and a generation method thereof.

  In recent years, microbubbles called nanobubbles (for example, bubbles having a diameter of 1 micrometer or less), microbubbles (for example, bubbles having a diameter of 50 micrometers or less when generated) have various excellent characteristics. It is used in various fields. For example, a technique relating to a nanobubble utilization method and apparatus is known in which nanobubbles can be used for cleaning various objects, purifying polluted water, etc. by utilizing the characteristics of nanobubbles (see, for example, Patent Document 1).

  This Patent Document 1 discloses a method and an apparatus for generating nanobubbles by electrolysis. However, since this apparatus requires an ultrapure water production apparatus, an ultrasonic generator, an electrolysis power supply apparatus, and the like, and the structure becomes complicated, development of an apparatus having a simpler structure has been demanded. Various other proposals have already been made on the generating apparatus and generating method for generating fine bubbles in this way.

  For example, a fluid swirl chamber defined by a cylindrical member, a first end wall member, a second end wall member, and the like, a fluid introduction hole that is introduced into the fluid swirl chamber from a tangential direction, and a fluid is discharged from the center line direction. A technique related to a fine bubble generating device having a gas swirl shear device including a fluid discharge hole is known (see, for example, Patent Documents 2 and 3).

  Also, a container body having a cylindrical space closed at one end side by a conical or truncated cone-shaped wall projecting toward the other end side and opened at the other end side, a gas introduction hole, and opened in a tangential direction There is also known a technique related to a swirling fine bubble generating apparatus including a pressurized liquid introduction port (see, for example, Patent Document 4). Furthermore, as a technique applied to decontamination of radioactive materials, there is known a technology that performs cleaning of radioactive materials that remove cesium by making use of the characteristics of nanobubbles (see, for example, Patent Document 5).

JP 2004-121962 A Patent No. 4129290 Japanese Patent No. 4118939 JP 2006-116365 A JP2013-140096A

  The fine bubble generator described in Patent Documents 2 and 3 refines a gas by a shearing force generated by a swirling flow generated in a cylindrical fluid swirling chamber. Further, in the swirl type fine bubble generator described in Patent Document 4, when gas is ejected from the outlet which is an opening of the apparatus container, the gas vortex tube portion is cut due to the swirl speed difference generated simultaneously with the ejection. As a result, fine bubbles having a diameter of 10 to 20 μm are generated. Furthermore, the technique described in Patent Document 5 is to wash the radioactive substance by elution or the like using nanobubble water having a mode particle diameter of 500 nm or less.

  As for microbubbles, it is generally said that nanobubbles are superior in various properties to microbubbles. In addition, even in the case of nanometer-order microbubbles, it is said that microbubbles that are refined to the order of several tens of nanometers have superior characteristics compared to microbubbles with a diameter of several hundred nanometers. ing. However, the techniques described in Patent Documents 2 to 4 described above still have room for improvement in terms of reliably and efficiently generating such bubbles, for example, fine bubbles having a diameter of several tens of nanometers. It was what remained. Further, Patent Document 5 discloses a technique for generating fine bubbles as such, but the size of the bubbles is not constant, the range of particle diameter is wide, and the bubbles are used effectively. Still have problems.

Therefore, there is a demand for the development of a method and apparatus for stably generating a fine bubble of a nanometer order with a smaller diameter than a conventional fine bubble of a nanometer order with a large diameter while maintaining a constant particle size for a long time. Has been.
An object of the present invention is to provide a fine bubble generating apparatus and a method for generating the same, which can make a fine bubble of a nanometer order having a small particle diameter into a stable bubble of a constant particle size and reliably and efficiently generate it. is there.

The present invention takes the following means in order to achieve the object.
The fine bubble generator of the present invention 1
A pump (10, 71) for pressurizing and discharging liquid to a predetermined pressure;
A gas supply body (22, 72) that mixes the gas (6) with the liquid (5) discharged by the pump (10, 71) to form a gas-liquid mixed fluid (7) having fine bubbles;
A rectangular parallelepiped box member having an injection nozzle for introducing and injecting the gas-liquid mixed fluid (7) into the interior, forming a three-dimensional flat space therein, and the gas-liquid mixed fluid (7) When the jet nozzle is jetted into the flat space, cavitation occurs to generate and crush bubbles, and the jetted gas-liquid mixed fluid (7) generates a vortex that flows in a vortex in the flat space. The jet-type fine bubble generating unit (30) and the jet-type fine bubble generating unit (30) which make the fine bubbles finer by the energy generated by the crushing of the bubbles and the shearing force generated by the vortex flow The fine bubble-containing water (8) comprises a jet injection nozzle (60) that re-fines the fine bubbles to inject into fine bubble-containing water (9) containing fine bubbles having a constant particle diameter.

The fine bubble generator of the second aspect of the present invention is the first aspect of the present invention.
The liquid is water (5), the gas is at least one selected from air (6), oxygen, and ozone, and the fine bubbles having a certain particle size are small in particle diameter of nanometer level. It is characterized by being a fine bubble.

The fine bubble generator of the present invention 3 is the present invention 1, 2,
In the jet type fine bubble generating part (30), when the flat space is represented by H, the general height of the space is represented by W, the general width thereof is represented by W, and the effective diameter of the injection port is represented by D1. The jet is jetted in the lengthwise direction in the direction of the center line of the space, and the generation conditions of the vortex are D1 <H and W / H ≧ 4.

The fine bubble generator of the present invention 4 is the present invention 1, 2,
The pump (10) has the function of the gas supply body. The pump (10) is provided with a gas supply port (22) in the vicinity of the liquid suction port (20), and the impeller (14) rotates to rotate the pump (10). It is a gas-liquid mixing pump (10) for discharging a gas-liquid mixed fluid (7) in which the gas bubbles are mixed in a liquid.

The fine bubble generator of the present invention 5 is the present invention 1, 2,
The gas supply body is an ejector (72) that sucks the gas (6) with the pressurized liquid (5) and performs the mixing.

The fine bubble generator of the present invention 6 is the present invention 1, 2,
The jet injection nozzle (60) extends coaxially from the outlet of the orifice (61), has a length 4 to 20 times the diameter of the orifice (61), and has an ejection hole (63). An injection nozzle having a cross-sectional shape in which the diameter gradually increases from the axial center along the axial direction by 20 degrees to 60 degrees from the inlet section having the same diameter as the orifice section (61) toward the downstream. To do.

  The fine bubble generating apparatus of the present invention 6 is the present invention 1, 2, wherein the jet injection nozzle extends coaxially from the outlet of the orifice part and has a length 4 to 20 times the diameter of the orifice part. The jet nozzle is a jet nozzle having a cross-sectional shape in which the diameter gradually increases from the axial center along the axial direction by 20 degrees to 60 degrees from the inlet section having the same diameter as the orifice section toward the downstream. And

The method of generating fine bubbles of the present invention 7
The liquid (5) sucked from the suction port of the pump (10, 71) is pressurized to a predetermined pressure, and the gas (6) is supplied from the gas supply body (22, 72) to the liquid to supply the gas-liquid mixed fluid (7). Generating and discharging
A step of injecting the gas-liquid mixed fluid into the flat space via the injection port into a jet type fine bubble generating part (30) which is a rectangular parallelepiped member and in which a three-dimensional flat space is formed;
Cavitation is generated in the gas-liquid mixed fluid (7) injected from the injection port into the flat space to generate and crush bubbles, and the air-liquid mixed fluid (7) is swung by the jet fluid of the gas-liquid mixed fluid (7). Generating a vortex that flows in a vortex, and generating fine bubble-containing water (8) including fine bubbles obtained by refining the bubbles by energy at the time of collapse of the bubbles and shearing force due to the vortex,
The ejection hole (63) extends coaxially from the outlet of the orifice part (61), has a length 4 to 20 times the diameter of the orifice part (61), and the ejection hole (63) has the orifice part (61). 61) The fine bubbles are contained in the jet injection nozzle (60) having a cross-sectional shape in which the diameter gradually increases from the axial center along the axial direction by 20 degrees to 60 degrees along the axial direction from the inlet portion having the same diameter as that of 61). And a step of passing water (8) to form fine bubble-containing water (9) containing fine bubbles obtained by re-refining the fine bubbles.

  The fine bubble generator of the present invention and the generation method thereof are mixed with a liquid sucked by a pump and a gas supplied by a gas supply body to generate a gas-liquid mixed fluid containing bubbles, and the bubbles are generated in a jet generation unit. In the cavitation phenomenon, the bubbles are made fine bubbles by the energy generated when the bubbles are crushed and the shearing force generated by the vortex caused by the Coanda effect or the like in the jet generating chamber.

  Further, the fine bubbles were re-fine by cavitation with a jet jet nozzle to obtain finer fine bubbles. As a result, it has become possible to more reliably and efficiently generate stable and stable fine bubbles having a small particle diameter of nanometer order. Therefore, the fine bubbles with a diameter of nanometer order generated by this fine bubble generator and its generation method are fixed fine bubbles with a small particle size. It was to contribute.

  Moreover, this fine bubble generating apparatus has a simple configuration and can generate high-quality fine bubbles with a small particle size of nanometer order with high reliability. By using the microbubble-containing fluid obtained by this microbubble generator, for example, when applied to decontamination of an object to be cleaned to which a radioactive substance (for example, radioactive cesium) adheres, the removal effect can be further enhanced. it can.

FIG. 1 is a configuration diagram showing an outline of a fine bubble generating apparatus according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view showing the configuration of the gas-liquid mixing pump in the fine bubble generating apparatus of FIG. FIG. 3 is a front view schematically showing the principle of jet generation in the fine bubble generation chamber of the jet type fine bubble generation unit constituting the fine bubble generation device. 4 is a cross-sectional view of FIG. 3 taken along line BB. FIG. 5 is a cross-sectional view showing the configuration of the jet injection nozzle. FIG. 6 is a configuration diagram showing an outline of the fine bubble generating apparatus according to the second embodiment of the present invention. FIG. 7 is an explanatory view showing the configuration of the ejector in the fine bubble generating apparatus of FIG. FIG. 8 is a data diagram showing the bubble particle size distribution of the fine bubble-containing water obtained in the present invention. FIG. 9 is a comparative data diagram showing the bubble size distribution.

[Embodiment 1]
Embodiment 1 of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing an outline of a fine bubble generating apparatus according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view showing the configuration of the gas-liquid mixing pump in FIG. FIG. 3 is an explanatory view schematically showing a jet flow generation principle in a fine bubble generation chamber of a jet type fine bubble generation unit constituting the fine bubble generation device, and FIG. 4 is a cross-sectional view taken along line BB in FIG. It is explanatory drawing of the cut cross section. FIG. 5 is a cross-sectional view showing the configuration of the jet injection nozzle.

  As shown in FIG. 1, the fine bubble generating device 1 according to the first embodiment of the present invention sucks a liquid (hereinafter referred to as “water 5”) and simultaneously takes in a gas (hereinafter referred to as “air 6”). A gas-liquid mixing pump (hereinafter referred to as “vortex pump 10”) that is supplied and gas-liquid mixed and discharged as a gas-liquid mixed fluid (hereinafter referred to as “gas-liquid mixed water 7”) is provided. This vortex pump 10 has a structure including a function of supplying air 6 which is gas in this example. In the first embodiment, a separate and independent gas supply body is not provided. Therefore, this vortex pump 10 has a function of generating fine bubbles in the form of bubbles by mixing with water as the air is supplied.

  In addition, the microbubble generator 1 of the first embodiment is connected to the vortex pump 10 to introduce the gas-liquid mixed water 7, and microbubbles [for example, a diameter of the order of nanometers (nm) on the order of cavitation] It has a jet type fine bubble generating unit 30 for generating fine bubbles. Further, the microbubble generator 1 is provided with a foot valve 44, a valve 42, and a pressure gauge 43 having a backflow prevention structure on the inflow side of the vortex pump 10 so that water does not fall even when the operation of the vortex pump 10 is stopped. Yes. Further, the vortex pump 10 accompanies the air 6 through the gas flow meter 46, the valve 47 and the check valve 48.

  Furthermore, the fine bubble generating device 1 includes a connection channel 41 provided between the fluid discharge unit 21 of the vortex pump 10 and the injection nozzle 32 at the fluid inlet to the jet type fine bubble generation unit 30. The jet nozzle is provided on the fluid outlet 33 side of the generator 30, the delivery channel 45 serving as a jet flow path from the jet nozzle, the jet jet nozzle 60, and the like. In the description of the first embodiment, the liquid is water 5 (for example, public tap water) and the gas is air 6. However, the liquid is another type of liquid, and the gas is another type of oxygen or ozone. Needless to say, a gas such as nitrogen may be used.

  As described above, the valve 42 and the pressure gauge 43 are connected to the water inflow side of the vortex pump 10, but the connection channel 41 is for the gas-liquid mixed flowing water 7 discharged from the vortex pump 10. A pressure gauge 50 and a flow meter 51 are provided. The pressure of the gas-liquid mixed flowing water 7 flowing in the connection channel 41 is set to a predetermined pressure (for example, 0.5 to 0.2 MPa). The pressure of the gas-liquid mixed water 7 can be confirmed with the pressure gauge 50.

  Further, a pressure gauge 49 is also connected to the delivery channel 45, and the pressure of the fine bubble-containing water 8 set to a predetermined pressure (for example, 0.4 to 0.1 MPa) can be confirmed. For example, when the pressure of the gas-liquid mixed water 7 supplied to the jet-type fine bubble generating unit 30 is 0.4 MPa, the pressure of the fine bubble-containing water 8 in the delivery channel 45 is 0.3 MPa. The pressure of the gas-liquid mixed water 7 is set so as to be larger than the pressure of the refined fine bubble-containing water 8.

  Next, the vortex pump 10 that is a gas-liquid mixing pump will be described in detail with reference to FIG. As shown in FIG. 2, the vortex pump 10 includes a pump body 11 having a liquid suction port 20 and a fluid discharge port 21, an impeller 14 provided in the pump body 11, and an air supply nozzle 22 that is a gas supply body. Etc. An annular boost channel 16 is formed in the pump body 11, and a liquid suction port 20 is formed in communication with the inlet portion 17 of the boost channel 16. A fluid discharge port 21 communicates with the boost channel 16 at the outlet 18 of the boost channel 16. On the other hand, an isolation portion 19 is formed between the inlet portion 17 and the outlet portion 18 of the pressure increasing flow path 16.

  An impeller 14 is rotatably supported by a bearing in the pump body 11. On the outer peripheral portion of the impeller 14, a small blade portion 12 in the radial direction formed at a predetermined pitch, and a blade groove portion 13 that is a concave groove is disposed between the small blade portions 12. By rotating the rotating shaft 15 integral with the center of the impeller 14 by a motor (not shown) provided outside the pump body 11, the small blade portion 12 and the blade groove portion 13 of the impeller 14 are It rotates in the pressure increasing flow path 16 concentric with the impeller 14. As the impeller 14 rotates, the water 5 is sucked from the liquid suction port 20.

  An air supply nozzle 22, which is a gas supply body, is inserted into and fixed to the liquid suction port 20 of the vortex pump 10. The air 6 supplied from the air supply nozzle 22 is configured to flow from the inlet portion 17 of the boost channel 16 into the boost channel 16. As described above, the vortex pump 10 has the annular pressure rising channel 16 formed around the impeller 14 rotatably supported in the pump body 11, and the inlet 20 of the pressure increasing flow channel 16. The air supply nozzle 22 for supplying the air 6 is inserted and fixed to the inlet portion 20.

  As shown in FIG. 1, the air 6 is introduced through an air flow meter 46, a valve 47, and a check valve 48, and is supplied from the air supply nozzle 22 into the vortex pump 10. The supplied air 6 and water 5 are mixed and stirred in the vortex pump 10, and the gas-liquid mixed water 7 obtained by mixing the water 5 and air 6 contains fine foam bubbles and is a fluid discharge unit 21. To the connection channel 41.

  That is, while the water 5 sucked into the liquid suction port 20 of the vortex pump 10 substantially goes around the booster passage 16 together with the impeller 14, between the inside of each blade groove 13 of the impeller 14 and the booster passage 16. The vortex flows into a vortex, and the pressure is increased as it travels through the pressure increasing flow path 16 and is discharged from the fluid discharge port 21 to the connection flow path 41. At this time, the inlet portion 17 of the pressure increasing flow path 16 has a negative pressure, and water 5 is sucked into the inlet portion 17 and air 6 supplied from the air supply nozzle 22 is also sucked.

  Since the water 5 and the air 6 are mixed and agitated by the vortex generated between the impeller 14 and the pressure increasing flow path 16, the water 5 and the air 6 move in the pressure increasing flow path 16. Mixed. That is, water 5 and air 6 are mixed to form gas-liquid mixed water 7 containing small diameter bubbles (small particles) and discharged from the fluid discharge port 21. That is, the air 6 mixed with the water 5 is subjected to a shearing force due to the vortex, and becomes a fine primary bubble (for example, a fine bubble having a diameter of the order of micrometers (μm)). . The gas-liquid mixed water 7 discharged to the connection flow path 41 is subsequently introduced into the jet flow type fine bubble generating unit 30.

  Next, the jet type fine bubble generating unit 30 will be described. As shown in FIGS. 3 and 4, the jet-type fine bubble generation section (hereinafter referred to as “microbubble generation section 30”) is a jet-type microbubble generation box (hereinafter referred to as “fine bubble generation box”) that has a flat rectangular parallelepiped shape. 31 ”). The fine bubble generation box 31 is arranged so that its longitudinal direction is vertical. A fluid inlet provided on one surface of the fine bubble generating box 31 serves as an injection port for injecting the gas-liquid mixed water 7 pressurized and discharged by the vortex pump 10 into the fine bubble generating box 31. The injection nozzle 32 is fixed. The injection nozzle 32 is an annular space having a cylindrical cross section of the injection port. This structure is known in Japanese Patent Application Laid-Open No. 2000-563, and the details thereof are omitted.

  The fine bubble generating box 31 forming the main body of the fine bubble generating unit 30 is connected to the fine bubble generating chamber 31a, the fluid inlet connected to the connection channel 41, the injection nozzle 32, and the delivery channel 45. A fluid outlet 33 or the like is formed. Inside the fine bubble generation box 31, a partitioned fine bubble generation chamber 31a is formed. The internal space V of the fine bubble generating chamber 31a is a three-dimensional box-shaped space that is flat, with the approximate horizontal height (thickness) of the space being H, the approximate width of the space being W, and the vertical direction. If the length of the nozzle is L and the effective diameter of the opening of the injection nozzle 32 provided in the fluid inlet portion is D1, the relationship is generally D1 <H, W / H ≧ 4, and W <L. That is, the internal space V of the fine bubble generating chamber 31a is preferably a flat and rectangular space.

  The gas-liquid mixed water 7 injected from the injection nozzle 32 decreases in pressure as the injection speed increases, and as a result of the pressure decreasing to the saturated vapor pressure, the liquid component (water component) evaporates and bubbles are generated. A phenomenon called cavitation occurs. As a result, fine bubbles due to the cavitation phenomenon are generated in the jet water in which the gas-liquid mixed water 7 is jetted from the jet nozzle 32 using the bubbles of the gas-liquid mixed water 7 as the bubble core.

  Thereafter, when the pressure lowered to the saturated vapor pressure gradually returns to the original pressure on the downstream side of the jet water, the bubbles are compressed and crushed. High-temperature and high-pressure energy generated when the bubbles are crushed is radiated to the surroundings, and the bubbles and fine bubbles in the jet water are refined by this energy. ) Is generated.

  The gas-liquid mixed water 7 jetted from the jet nozzle 32 becomes jet water and flows in the fine bubble generating chamber 31a. The main jet 34 of jet water is jetted in the direction of the approximate center line of the internal space V in the vertical direction. The main jets 34 and 34 ′ are curved and flow so as to be drawn toward one of the wall surfaces of the fine bubble generating chamber 31 a by the Coanda effect (effect in which the jet is drawn to a nearby wall). Moreover, since it flows so that it may curve also in a corner part, the main jets 34 and 34 'of jet water become a vortex which flows in a vortex. The main jets 34 and 34 'of the jet water undergo a drastic change in the direction of rotation of the vortex, resulting in a movement flow like the main jets 34 and 34' shown in FIGS. Adhering vortices 35 and 35 that are low-pressure vortices are generated at the eight corners of the fine bubble generating chamber 31 by the Coanda effect.

  Therefore, the flow (vortex) of the main jets 34 and 34 ′ is generated in the fine bubble generating chamber 31 a in the direction of the arrow as illustrated in FIG. 3 or 4, for example. The flow of the main jets 34 and 34 'is not constant and stable, and is in the direction of the arrow + w or arrow -w in the plane of the width W, and in the plane of the thickness H is the arrow + h or arrow- As it sways in the h direction, the flow of motion changes so that the direction of rotation of the vortex changes drastically.

  That is, the main jets 34 and 34 'cause cavitation, are unstable and flow while shaking, and a vortex flow is generated. In other words, a vortex phenomenon with a strong stirring force occurs in the fine bubble generating chamber 31a, and the rotational direction of this vortex flow changes drastically. Further, the jets whose rotation direction changes drastically such as the main jets 34 and 34 ′ and the attached vortex flows 35 and 35 give extremely strong shearing force to the jet water in which the gas-liquid mixed water 7 and the fine bubbles are mixed.

  This shearing force promotes mixing of the microbubbles and the jet water, and also shears the microbubbles to generate microbubbles (nanobubbles) on the order of nanometers (nm) having a very small diameter. The secondary microbubbles that have undergone such miniaturization become, for example, microbubbles with a diameter of several tens of nanometers or less, and the primary microbubbles change into secondary microbubbles that are mixed into the jet water and fine Bubble-containing water 8 is obtained. The fine bubble-containing water 8 generated in this way is discharged from the fine bubble generation unit 30 through the fluid outlet 33 and then guided to the jet injection nozzle 60. By passing through the nozzle 60 for jet injection, the bubbles of the fine bubble-containing water 8 are re-refined to become tertiary fine bubbles, and the bubble particles are further reduced in particle size and are stable fine particles with a constant size. It becomes a bubble. The fine bubble-containing water 9 including the tertiary fine bubbles is collected through the connection channel 49 and used for various purposes such as cleaning.

  In this way, by the configuration of the fine bubble generating unit 30 in which the fine bubbles are generated and the configuration in which the jet injection nozzle 60 for further re-miniaturization is provided, the bubbles are further refined and the fine bubbles containing the fine bubbles are contained. The water 9 has a further effect on cleaning and the like. Any jet injection nozzle may be used as long as it has a function of generating cavitation and miniaturizing bubbles, but the jet injection nozzle 60 having the following configuration is preferable.

[Jet injection nozzle 60]
Next, the jet injection nozzle 60 for re-miniaturizing fine bubbles will be described in detail with reference to FIG. The jet injection nozzle 60 is known from Japanese Patent Publication No. 4-43712. The configuration of the jet spray nozzle 60 is as follows. The jet hole 63 of the jet injection nozzle 60 extends coaxially from the outlet of the orifice portion 61, has a length 4 to 20 times the diameter of the orifice portion 61, and extends from the inlet portion having the same diameter as the orifice portion 61. It has a cross-sectional shape whose diameter gradually increases toward the downstream along the axial direction at an angle of 20 ° to 60 ° with the axial center.

More specifically, the jet injection nozzle 60 is connected to the flow path 45 via the piping member 62. An orifice portion 61 is formed in the jet injection nozzle 60, and an ejection hole 63 is further provided downstream of the orifice portion 61. The side wall 64 is a conical wall forming the ejection hole 63. The angle θ indicates an angle between the axis C of the orifice 61 and the side wall 64 that forms the ejection hole 63. Further, in this nozzle shape, when the diameter of the orifice portion 61 is d, the length L ₁ of the ejection hole 63 is set to 4 to 20 times d. Furthermore, the angle θ is in the range of 20 ° to 60 ° in this example as described above in order to cause a cavitation phenomenon between the ejected liquid and the surrounding liquid.

  In this range, it has been demonstrated that extremely significant cavitation is generated, energy attenuation of the jet liquid is small, and jet energy can effectively act on the jet target. When the pressurized fine bubble-containing water 8 is supplied to the jet injection nozzle 60 having such a configuration, it becomes a high-speed fluid at the orifice portion 61 and is ejected to the ejection hole 63. The jet fluid promotes the generation of cavitation with the surrounding fluid by the relationship between the jet hole 63 and the side wall 64 having an angle, thereby further crushing the fine bubbles. Thereby, the fine bubbles of the fine bubble-containing water 8 from the fine bubble generating unit 30 change from the secondary fine bubbles to the tertiary fine bubbles. Moreover, the energy attenuation of the jet fluid accompanying this decreases. Therefore, this injection energy can be effectively applied to an injection target such as cleaning.

  In this way, by performing the process of refining the fine bubbles again through the jet injection nozzle 60 to form the tertiary fine bubbles, the bubbles become finer and constant water bubbles and become fine bubbles that maintain a stable state. . The fluid from the jetting nozzle 60 becomes the fine bubble-containing water 9 including tertiary fine bubbles. The use of the fine bubble-containing water 9 containing the re-refined bubbles for cleaning produces a great effect. This fine bubble-containing water 9 is finally stored by flowing in the delivery flow path 52 and used for a desired place, a desired purpose, and the like. The jet injection nozzle 60 may have a nozzle structure described in Japanese Patent Application Laid-Open No. 2000-563, which is the invention related to the present applicant, other than those described above.

  The fine bubble-containing water 9 generated in such a process was contained in the water for a long time without being affected by buoyancy while the Brownian motion of the fine bubbles having a diameter of nanometer order in water. It will be in the form. Further, when the fine bubble-containing water 9 is used for a cleaning operation or the like, the cleaning effect is greatly improved by entering deep into a minute gap and adsorbing and peeling off the original components such as dirt. For example, with this fine bubble-containing water 9, especially when decontamination of an object to be cleaned to which a radioactive substance (for example, radioactive cesium) is attached, the concentration of the radioactive substance is lower than that of the conventional one, and decontamination is surely performed. Can do. That is, fine bubbles having a diameter of nanometer order can more effectively clean the object to be cleaned than the conventional one.

The results of the example of the first embodiment are shown in Table 1 and data below.
[Operating conditions of the example]
Pump type: Eddy current pump (KTM25ND15Z-000 manufactured by Nikuni Co., Ltd. (head office: Kanagawa, Japan))
Pump discharge pressure: 0.3MPa
Size of jet type fine bubble generating part: W: 160mm, H: 40mm, L: 320mm
Outlet pressure of jet type fine bubble generating part: 0.2MPa

Table 1 is a graph of measured numerical values, in which the average diameter, mode diameter (most frequent particle diameter), and unit volume (ml) of the samples # 1 to # 3 are measured and displayed.

  FIG. 8 is a graph of the measured values according to Table 1. The bubble particle size distribution showing the particle size distribution measurement result of the fine bubble-containing water 9 containing the tertiary fine bubbles generated by the apparatus of the present invention is shown in FIG. It is a data figure shown. This data diagram shows the average value of the measured values of the three samples in Table 1. The particle size measurement device used here was a nanoparticle analyzer (manufactured by NanoSight Ltd, LM10-HSBT14 (EMCCD camera, blue laser (405 nm, 65 mw)). This device can measure the Brownian motion of nanoparticles in a liquid. The particle size distribution of each size and concentration is converted into data, and the particle size distribution of each size and concentration is converted into data as shown in the data diagram. It can be seen that the average diameter is concentrated from 90 to 125 nm, and the graphed data curve shows the average value of the three samples, but only forms one peak. The sample (# 1 to 3) also shows that the fine bubbles are small and the particle size range is almost constant and stable.

(Comparative example)
FIG. 9 is a comparative data diagram showing the bubble size distribution. This data chart is obtained by measuring the fine bubble-containing water 8 including secondary fine bubbles ejected from the fine bubble generating portion. According to this data diagram, in comparison with the data diagram of the above example, there are a plurality of peaks in the data curve corresponding to the particle diameter, and although it is a nanovalve, the particle size range is wide compared to FIG. According to the data, it extends in the range of 100 to 400 nm. It shows that fine bubbles having different particle diameters exist in the water containing fine bubbles. This measurement was also analyzed with the nanoparticle analyzer.

(Embodiment 2)
Next, the configuration of the second embodiment will be described. FIG. 6 is a configuration diagram showing an outline of the fine bubble generating device 70 according to the second embodiment of the present invention. FIG. 7 is an explanatory diagram of an ejector applied to this embodiment. In this embodiment, the water 5 sucked and discharged by the normal pump 71 that sucks only the water 5 is supplied to the water 5 in the flow path by the gas supply body provided in the connection flow path 41, that is, the ejector 72. Are mixed to obtain gas-liquid mixed water 7. As will be described later, the ejector 72 is a kind of pump that does not have electrical power using a pressure difference and an operating part. As shown in FIG. 6, water 5 is pumped up by a pump 71 through a foot valve 73, and the water 5 passes through a flow path 41 and is guided to an ejector 72.

  Air 6 is taken into the ejector 72 through an air flow meter 75, a valve 76, and a check valve 77, and the water 5 from the pump 71 becomes gas-liquid mixed water 7 by passing through the ejector 72. This gas-liquid mixed water 7 is foamy and has fine bubbles, and includes primary fine bubbles. The gas-liquid mixed water 7 is guided to the above-described fine bubble generating unit 30 including primary fine bubbles. After being guided to the fine bubble generating unit 30, the gas-liquid mixed water 7 is made into fine bubbles to become fine bubble-containing water 8 having secondary fine bubbles. The fine bubble-containing water 8 is guided to the jet injection nozzle 60, becomes the fine bubble-containing water 9 including the refined tertiary next fine bubbles, and is discharged to the delivery flow path 52. Since the generation of secondary and tertiary fine bubbles is the same as that described above, detailed description thereof is omitted.

  Next, the configuration of the ejector 72 will be described. As shown in FIG. 7, the ejector 72 constitutes a body 80 of a member having a T-tube in the middle of the piping. One connection port 81 of the body 80 corresponding to the T-shaped horizontal line is connected to the pump side, and the other connection port 82 is connected to the fine bubble generating unit 30 side. This connection is not shown, but is connected to each pipe via a joint. A portion corresponding to a T-shaped vertical line is a gas suction port 83. The nozzle 84 and the diffuser 85 are opposed to the inside 86 of the body at a predetermined distance, and the water 5 ejected from the nozzle 84 is ejected toward the inlet of the diffuser 85.

  At this time, during injection from the nozzle 84, negative pressure (Bernoulli's theorem) is generated in the body 86, and the air 6 is sucked from the suction port 83. By sucking the air 6, the water 5 is mixed and injected into the diffuser 85 as gas-liquid mixed water containing bubbles. The gas-liquid mixed water 7 discharged from the diffuser 85 contains primary fine bubbles as in the above-described embodiment, and is guided to the fine bubble generating unit 30. Thereafter, fine bubbles are generated through the same process as described above.

  Although the embodiments have been described above, the microbubble generator 1 of the present invention can generate microbubbles with a small particle diameter and can hold the microbubbles as a group of particles having a constant size. There is a big feature in the point. Regarding fine bubbles, it is generally said that large bubbles float on the surface of water due to buoyancy in water and disappear, while small bubbles stay in water for a long time and are stably held. For this reason, fine bubbles such as nanobubbles are characterized in that they are retained without disappearing even if they are left in water for a long time. The smaller the nanobubble particle size, the greater the effect, and the smaller the particle size, the greater the effect.

  As mentioned above, although each embodiment of the present invention has been described, the present invention is not limited to this embodiment, and it is possible to make changes within a scope that does not depart from the purpose and spirit of the present invention. Needless to say.

DESCRIPTION OF SYMBOLS 1 ... Fine bubble generator 5 ... Water 6 ... Air 7 ... Gas-liquid mixed water 8 ... Fine bubble containing water 9 ... Fine bubble containing water 10 ... Eddy current pump 11 ... Pump main body 14 ... Impeller 30 ... Jet type fine bubble generating part DESCRIPTION OF SYMBOLS 31 ... Jet type fine bubble generation box 32 ... Injection nozzle 33 ... Fluid outlet part 34, 34 '... Main jet 35 ... Adhesive jet V ... Internal space W ... Internal space width H ... Internal space height 60 ... For jet injection Nozzle 71 ... Pump 72 ... Ejector

Claims (7)

A pump (10, 71) for pressurizing and discharging liquid to a predetermined pressure;
A gas supply body (22, 72) that mixes the gas (6) with the liquid (5) discharged by the pump (10, 71) to form a gas-liquid mixed fluid (7) having fine bubbles;
A rectangular parallelepiped box member having an injection nozzle for introducing and injecting the gas-liquid mixed fluid (7) into the interior, forming a three-dimensional flat space therein, and the gas-liquid mixed fluid (7) When the jet nozzle is jetted into the flat space, cavitation occurs to generate and crush bubbles, and the jetted gas-liquid mixed fluid (7) generates a vortex that flows in a vortex in the flat space. The jet-type fine bubble generating unit (30) and the jet-type fine bubble generating unit (30) which make the fine bubbles finer by the energy generated by the crushing of the bubbles and the shearing force generated by the vortex flow A fine bubble generating apparatus comprising: a jet injection nozzle (60) for refining the fine bubbles into water (9) containing fine bubbles having a constant particle size by spraying the fine bubble-containing water (8). . In the fine bubble generator described in Claim 1,
The liquid is water (5), the gas is at least one selected from air (6), oxygen, and ozone, and the fine bubbles having a certain particle size are small in particle diameter of nanometer level. A microbubble generator characterized by being a microbubble. In the fine bubble generator described in claim 1 or 2,
In the jet type fine bubble generating part (30), when the flat space is represented by H, the general height of the space is represented by W, the general width thereof is represented by W, and the effective diameter of the injection port is represented by D1. The jet is jetted in the lengthwise direction in the direction of the center line of the space, and the generation conditions of the eddy current are D1 <H and W / H> 4. apparatus. In the fine bubble generator described in claim 1 or 2,
The pump (10) has the function of the gas supply body. The pump (10) is provided with a gas supply port (22) in the vicinity of the liquid suction port (20), and the impeller (14) rotates to rotate the pump (10). A fine bubble generating device comprising a gas-liquid mixing pump (10) for discharging a gas-liquid mixed fluid (7) in which gas bubbles are mixed in a liquid. In the fine bubble generator described in claim 1 or 2,
The fine gas bubble generator according to claim 1, wherein the gas supply body is an ejector (72) that sucks the gas (6) with the pressurized liquid (5) and performs the mixing. In the fine bubble generator described in claim 1 or 2,
The jet injection nozzle (60) extends coaxially from the outlet of the orifice (61), has a length 4 to 20 times the diameter of the orifice (61), and has an ejection hole (63). An injection nozzle having a cross-sectional shape in which the diameter gradually increases from the axial center along the axial direction by 20 degrees to 60 degrees from the inlet section having the same diameter as the orifice section (61) toward the downstream. A fine bubble generator. The liquid (5) sucked from the suction port of the pump (10, 71) is pressurized to a predetermined pressure, and the gas (6) is supplied from the gas supply body (22, 72) to the liquid to supply the gas-liquid mixed fluid (7). Generating and discharging
A step of injecting the gas-liquid mixed fluid into the flat space via the injection port into a jet type fine bubble generating part (30) which is a rectangular parallelepiped member and in which a three-dimensional flat space is formed;
Cavitation is generated in the gas-liquid mixed fluid (7) injected from the injection port into the flat space to generate and crush bubbles, and the air-liquid mixed fluid (7) is swung by the jet fluid of the gas-liquid mixed fluid (7). Generating a vortex that flows in a vortex, and generating fine bubble-containing water (8) including fine bubbles obtained by refining the bubbles by energy at the time of collapse of the bubbles and shearing force due to the vortex,
The ejection hole (63) extends coaxially from the outlet of the orifice part (61), has a length 4 to 20 times the diameter of the orifice part (61), and the ejection hole (63) has the orifice part (61). 61) The fine bubbles are contained in the jet injection nozzle (60) having a cross-sectional shape in which the diameter gradually increases from the axial center along the axial direction by 20 degrees to 60 degrees along the axial direction from the inlet portion having the same diameter as that of 61). A method of generating fine bubbles, comprising: passing water (8) to form fine bubble-containing water (9) containing fine bubbles obtained by re-refining the fine bubbles.

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