JP2010029774A - Fine bubble generating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fine bubble generating apparatus capable of generating efficiently a large amount of fine bubbles uniform in diameter. <P>SOLUTION: The fine bubble generating apparatus generating fine bubbles includes a supply section supplying a gas/liquid mixed fluid, a body having a hollow section in which the mixed fluid supplied from the supply section is separated into a gas and a liquid to form each rotating flow of the gas and the liquid and a discharge section forming the rotating flow of the gas into bubbles and discharging the bubbles together with the liquid. The body includes a spiral inside-wall surface and at least one guide section arranged along the spiral inside-wall surface and separating the mixed fluid into two or more spiral passages to guide the mixed fluid to the hollow section. The spiral inside-wall surface causes the mixed fluid supplied from the supply section to flow in such a spiral form that the swirling surface of the mixed fluid is perpendicular to the direction of the discharge section. The spiral passages are contracted with respect to the supply section. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fine bubble generating apparatus that mixes liquid and gas into a generator body to generate fine bubbles in a target liquid.

  Various technologies have been developed for the bubble supply technology for dissolving gases (eg, oxygen, ozone, carbon dioxide, etc.) in liquids (eg, water, seawater, alcohol, etc.). It is applied in industrial fields such as aquaculture and health equipment. In this bubble supply technique, in order to dissolve a large amount of gas in the liquid, it is effective to increase the contact area ratio between the gas and the liquid by making the gas into bubbles and reducing the bubble diameter.

  As a conventional bubble generation device, for example, a pressure-decompression type bubble generation that generates a bubble by mixing and pressurizing a liquid and a gas, dissolving the gas in the liquid, and then rapidly depressurizing the gas-liquid mixed fluid Apparatus. Moreover, a swirl type microbubble generator is mentioned as what shows the effectiveness of microbubble itself rather than the said bubble generator (patent document 1 and patent document 2). The fine bubbles having a diameter of about 50 μm or less, which are generated by the swirling fine bubble generator, are widely used for sterilization of domestic water, waste water treatment, and the like.

  However, the conventional bubble generator has the following problems. That is, in the swirl type fine bubble generators described in Patent Document 1 and Patent Document 2, since the liquid and the gas are mixed within the conical narrowness, the bubble diameter varies, and bubbles having a large bubble diameter are ejected. The As a result, it is difficult to dissolve all of the supply gas as fine bubbles in the liquid to be processed, and the void ratio must be reduced in order to ensure the contact dissolution rate of the supply gas close to 100%.

WO00 / 69550 JP 2006-116365 A

  The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a fine bubble generating apparatus capable of efficiently generating a large amount of fine bubbles having a uniform bubble diameter.

  The inventors of the present application have studied a microbubble generator in order to solve the conventional problems. As a result, the inventors have found that the object can be achieved by adopting the following configuration, and have completed the present invention.

  That is, the fine bubble generator according to the present invention is a fine bubble generator that generates fine bubbles, a supply unit that supplies a mixed fluid composed of a gas and a liquid, and the mixed fluid supplied from the supply unit as a gas. And a main body provided with a hollow portion that forms each swirl flow separated into liquid, and a discharge portion that discharges the gas that has turned into swirl flow together with the liquid into bubbles. A spiral inner wall surface, and at least one guide portion that is provided along the spiral inner wall surface and that divides the fluid mixture into a plurality of spiral flow paths and guides the mixed fluid to the hollow portion. The inner wall surface is configured to flow the mixed fluid supplied from the supply unit in a spiral shape so that the spiral surface is perpendicular to the direction of the discharge unit, and the spiral flow path is the supply channel The diaphragm structure That.

  According to the above configuration, the mixed fluid supplied from the supply unit is caused to flow by being centrifugally swirled in the plurality of spiral flow paths formed by the spiral inner wall surface and the guide unit. Can be reduced. Further, since the spiral flow path has a constricted structure with respect to the supply section, the mixed fluid is compressed, and as a result, the flow of the mixed fluid can be changed to a high-speed flow. Furthermore, since the inner wall surface of the main body is spiral, flow resistance between the mixed fluid and the inner wall surface and occurrence of stagnation are reduced. Thereby, the flow of mixed fluid can be made into a spiral high-speed flow.

  The mixed fluid that has become a high-speed flow flows into the hollow portion and further swirls within the hollow portion. At this time, due to the specific gravity difference between the liquid and the gas, centrifugal force acts on the liquid in the mixed fluid, and centripetal force acts on the gas. As a result, the liquid becomes a high-speed swirling flow, while the gas converges on the central axis to form a negative pressure gas axis. Furthermore, the liquid that has turned into a high-speed swirling flow is in a state of being pressed against the external liquid collected by the negative pressure in the vicinity of the discharge portion. At this time, the gas collected on the negative pressure gas shaft passes through a gap formed by the external liquid and the liquid rotating at high speed while undergoing shearing, and is discharged in a large amount together with the liquid as fine bubbles. That is, the fine bubble generator having the above-described configuration can generate a large amount of fine bubbles having a small bubble diameter as compared with the conventional bubble generator.

  In the above configuration, an introduction port for introducing the mixed fluid to the hollow portion is provided between the guide portion and the spiral inner wall surface and between the guide portions, respectively, and the opening area of all the introduction ports Is preferably in the range of 7:10 to 9:10.

  By setting the ratio of the sum of the cross-sectional areas of all the inlets to the cross-sectional area of the supply unit within the above numerical range, the mixed fluid supplied from the supply unit is allowed to flow through the spiral channel. The flow rate can be increased by the squeezing effect. As a result, for example, the speed of the high-speed swirling flow of the gas and liquid swirling in the hollow portion can be increased by 10 to 20% or more compared with the case where the ratio is 10:10. Thereby, fine bubbles can be generated more efficiently.

  In the above-described configuration, the inlet provided between the guide portion and the spiral inner wall surface opens in a tangential direction on the spiral surface of the spiral inner wall surface, and the guide portion is between the guide portions. The introduction port provided is preferably opened in the tangential direction in the spiral surface of the wall surface of the guide portion.

  Thereby, when the mixed fluid which has flowed through the spiral flow path flows into the hollow portion, it is possible to suppress the flow resistance as much as possible. As a result, it can be supplied as a high-speed fluid into the hollow portion, and the generation of fine bubbles can be made more efficient.

  In the above configuration, a circulation channel that divides the spiral channel and circulates the mixed fluid is provided between the spiral inner wall surface and the guide portion, and the opening of the circulation channel has the opening described above. It is preferable that the opening area is smaller than the opening area of the introduction port.

  The said structure WHEREIN: By making the opening area of the opening part of a circulation flow path smaller than the opening area of an inlet, an injection force can be provided to the mixed fluid which flows out out of the said opening part. Further, since the opening is located in the vicinity of the mixed fluid supply unit, the flow pressure of the mixed fluid supplied from the supply unit causes a tensile force to act on the mixed fluid flowing in the circulation flow path. As a result, the flow rate of the flowing mixed fluid can be further accelerated, and fine bubbles can be generated more efficiently.

  The said structure WHEREIN: It is preferable that the gas supply part which supplies the said gas is provided in the vicinity of the said opening part.

  When the liquid flows through the flow path, a pulling action for sucking the gas in the flow direction works, and therefore, a negative pressure is generated at the gas supply position. Thereby, gas can be self-priming mixed with the flowing liquid. Further, by providing the gas supply unit, for example, it is possible to use a means for forcibly transporting gas using an air pump or the like.

  The said structure WHEREIN: It is preferable that the cross-sectional shape of the said inlet is a rectangular shape. When the cross-sectional shape is rectangular, the mixed fluid can be supplied to the hollow portion in a state along the inner wall surface of the hollow portion as much as possible as compared with the circular shape. Thereby, the speed of the high-speed swirling flow of the gas and liquid in the hollow portion can be further increased, and more efficient generation of fine bubbles becomes possible.

The present invention has the following effects by the means described above.
That is, according to the present invention, a plurality of spiral flow paths are provided, and the flow paths have a throttle structure with respect to the supply section, so that the mixed fluid can be supplied to the hollow section as a high-speed flow. it can. Thereby, the speed of the high-speed swirling flow of the gas and liquid swirling in the hollow portion can be increased, and an effect of efficiently generating a large amount of fine bubbles is achieved.

(Embodiment 1)
Embodiments of the present invention will be described below with reference to the drawings. However, parts that are not necessary for the description are omitted, and some parts are illustrated by being enlarged or reduced for easy explanation. FIG. 1 is an explanatory diagram showing a microbubble generator according to the present embodiment, where FIG. 1A shows the inside of the microbubble generator, and FIG. 1B shows a spiral flow path. . FIG. 2 is an explanatory view schematically showing the behavior of the mixed fluid and the generation mechanism of the fine bubbles inside the fine bubble generator.

  As shown in FIGS. 1 (a) and 1 (b), a microbubble generator 10 according to the present embodiment includes a supply unit 11 that supplies a mixed fluid, a main body 13 that includes a hollow portion 15, and a liquid. It has at least the discharge part 17 which discharges a fine bubble.

  The mixed fluid used in the present invention is a fluid in a state where a gas (gas phase) and a liquid (liquid layer) are mixed. In the present invention, the mixed fluid is used and the supply section 11 is provided for supplying the mixed fluid for the following reason. That is, in the conventional bubble generating device, the liquid and the gas are individually supplied into the hollow portion without using the mixed fluid. The gas is supplied, for example, by providing a gas inlet at the bottom of the central axis of the hollow portion. In such a conventional bubble generating device, it is necessary to pressurize the inside of the hollow portion in order to generate fine bubbles. However, when the inside of the hollow portion is excessively pressurized, there is a problem that the liquid flows backward to the gas introduction hole and the operability is lowered. In the present invention, since the mixed fluid composed of gas and liquid is used and the supply to the hollow portion is only the supply portion 11, it is possible to avoid the occurrence of the above-described problem.

  The gas in the mixed fluid includes air, inert gas such as hydrogen, argon or radon, oxidant such as oxygen or ozone, acid such as carbon dioxide, hydrogen chloride, sulfurous acid, nitrogen oxide or hydrogen sulfide. Examples thereof include alkaline gases such as gas and ammonia. Examples of the liquid include water and a liquid having a higher viscosity than water. Examples of liquids having a higher viscosity than water include solvents such as toluene, acetone and alcohol, fuels such as petroleum and gasoline, foods and beverages such as edible fats and oils, beer and other chemicals, and health such as bath water Goods, environmental water such as lake water, septic tank contaminated water, etc.

  The means for mixing the gas with the liquid is not particularly limited. For example, a self-intake body introduction port is provided on the suction side (negative pressure liquid) of the liquid pump, and a small-diameter pipe (made of vinyl, plastic, metal, or the like) is bonded to the self-intake body introduction port. Next, the small-diameter pipe is fixed so as to have a spiral shape, and an intake gas amount regulator (such as a valve) is installed in the small-diameter pipe. By providing the intake gas amount regulator, the gas supply amount can be set to the best state in accordance with the pump performance.

  The gas mixed in the liquid by the above method is crushed to a diameter of several millimeters by the suction mechanism (impeller) of the liquid pump. The liquid pump is connected to the supply unit 11 by a pipe, and the mixed fluid is supplied to the fine bubble generating device 10 through the pipe.

  The constituent material of the main body 13 is not particularly limited, and examples thereof include acrylonitrile / butadiene / styrene (ABS) resin and SUS-304.

  The main body 13 includes a spiral inner wall surface 19 that causes the mixed fluid supplied from the supply unit 11 to flow spirally so that the spiral surface is perpendicular to the direction of the discharge unit 17. Further, guide portions 12 and 14 are provided along the spiral inner wall surface 19. The spiral inner wall surface 19 and the guide portions 12 and 14 form a flow path 16 that causes the mixed fluid to flow in a plurality of spiral shapes.

  By causing the mixed fluid to flow as a dispersed flow through the plurality of spiral flow paths 16, the flow resistance received from the wall surface can be reduced, and as a result, a high-speed flow can be achieved. The mixed fluid guided to the spiral flow path 16 flows while being swirled along the spiral flow path 16 by the pressure and the flow velocity. During the flow, the gas and liquid are mixed more vigorously and become more uniform.

  An inflow port 18 a is formed between the guide portion 12 and the spiral inner wall surface 19. In addition, an inflow port 18 b is formed between the guide portion 12 and the guide portion 14. The cross-sectional shapes of the inflow ports 18a and 18b are not particularly limited, but are preferably rectangular. Moreover, it is preferable that each opening area is the same. By making the opening area the same, the supply amount of the mixed fluid to each flow path 16 can be made uniform.

  An introduction port 20 a is formed between the guide portion 12 and the spiral inner wall surface 19. An introduction port 20 b is formed between the guide portion 12 and the guide portion 14. The introduction ports 20a and 20b are preferably opened in a tangential direction on the spiral surface of the spiral inner wall surface. Thereby, when the mixed fluid which has flowed through the spiral flow path 16 flows into the hollow portion 15, it is possible to suppress the flow resistance as much as possible.

  Moreover, the cross-sectional shape of the inlets 20a and 20b is not particularly limited, but is preferably rectangular. Furthermore, it is preferable that each opening area is the same. By making the opening area the same, the supply amount of the mixed fluid to the hollow portion 15 can be made uniform. In addition, considering the manufacturing cost and the difficulty of production, it is preferable to provide two or three introduction ports.

  Here, in the present invention, it is necessary that the spiral flow path has a throttle structure with respect to the supply unit. In order to obtain a diaphragm structure, in the present embodiment, it is preferable that the ratio of the sum of the opening areas of the introduction port 20a and the introduction port 20b and the opening area of the supply unit 11 is 7:10 to 9:10. 8.5: 10-9: 10 is more preferable. Thus, until the mixed fluid supplied from the supply unit flows through the spiral flow path, the flow velocity and the fluid pressure are continuously increased by the throttling effect and the centrifugal force due to the circular motion. Can do. As a result, for example, compared with the case where the ratio of the sum of the cross-sectional areas of all the inlets to the cross-sectional area of the supply part is 10:10, the speed of the high-speed swirling flow of the gas and liquid swirling in the hollow part is 10 It can be increased by ~ 20%. This phenomenon is the same as the principle that, for example, when the mouth of the hose is slightly crushed with a finger, the liquid is ejected farther. If it is out of the numerical range, the flow rate itself required for high-speed rotation decreases, which is not preferable.

  The mixed fluid supplied from the inlet 20a and the inlet 20b becomes a high-speed swirling flow in the hollow portion 15 (see FIG. 2). At this time, due to the difference in specific gravity between the liquid and the gas, centrifugal force acts on the liquid and centripetal force acts on the gas. As a result, the gas and liquid are separated, and the gas converges on the central axis to form the negative pressure gas axis 21. The liquid becomes a high-speed swirling flow 23 and flows around the negative pressure gas shaft 21.

  The hollow portion 15 has a circular cross-sectional shape, and has a narrowed shape that becomes narrower as it approaches the discharge portion 17. This shape is not particularly specified as long as it has a circumference, such as a cone, a semicircle, or a sphere. Therefore, as the high-speed swirl flow 23 approaches the discharge unit 17 while swirling, the swirl speed increases and the pressure increases. Then, the gas and the liquid are mixed again in the vicinity of the discharge unit 17 to become a mixed fluid having the maximum turning speed and pressure. This mixed fluid is pressed against the external negative pressure liquid, and a gap 31 is formed by the external negative pressure liquid and the mixed fluid rotating at high speed. The rotation speed of the external negative pressure liquid is slower than the rotation speed of the mixed fluid rotating at high speed. The gas is severely sheared by the difference in rotational speed between the two and the action that the liquid is forced to be discharged to the outside of the main body 13. As a result, fine bubbles having a bubble diameter of 50 μm or less, and further 10 μm or less are generated. The external negative pressure liquid means an external liquid drawn in the vicinity of the discharge portion 17 because the external negative pressure liquid is close to a vacuum due to the formation of the negative pressure gas shaft 21. The bubble diameter is a value measured by a digital camera measuring instrument.

  Fine bubble generating apparatuses 10 and 40 according to the present embodiment are installed and used in a liquid. Specifically, for example, it can be used in a deep place (for example, a depth of 5 m or more) such as a pond, a lake (including a dam lake), or the sea. Moreover, the fine bubble generator 40 can be used without being limited to the type of the liquid pump. Further, for example, it is possible to eliminate uneven gas supply, which may occur when a plurality of liquid pumps are connected to each other through piping or the like.

The use conditions of the fine bubble generating device 10 are appropriately set according to the supply amount and head (pressure) of the pump used and the pipe diameter of the pipe connected to the supply unit 11. For example, when the cross-sectional shape of the hollow portion 15 is circular, and the maximum cross-sectional area and 3.5cm ² ~50.0cm ^2, when the inner volume and 36.0cm ³ ~330cm ^3, the opening area of the supply unit 11 ^is preferably in the range of 0.7cm ² ~5.0cm 2. When the opening area is less than 0.7 cm ² , it may be difficult to supply a sufficient amount of the mixed fluid. On the other hand, if the opening area exceeds 5.0 cm ² , there is an inconvenience in terms of cost of the pump and the like. Further, when the opening area of the discharge portion 17 ^is preferably in the range of 0.8cm ² ~18.0cm 2. When the opening area is less than 0.7 cm ² , it may be difficult to supply a sufficient amount of the mixed fluid. On the other hand, if the opening area exceeds 19 cm ² , the bubble diameter varies, which is disadvantageous. Furthermore, the opening areas of the inlets 20 a and 20 b are set so that the sum of them is within the range of 7:10 to 9:10 with respect to the opening area of the supply unit 11.

  Under the design conditions, for example, when the pump pressure of the pump for supplying the mixed fluid is 0.15 MPa and the supply amount is 20 L / min, the turning speed in the hollow portion 15 is about 450 Hz or more. In addition, there exists a tendency for turning speed to become slow, so that a hollow part volume is large. The turning speed can be obtained by measuring the sound generated by the swirling vortex and measuring the rotation speed of the swirling vortex.

  The pump pressure is preferably in the range of 0.01 MPa to 0.8 MPa, more preferably in the range of 0.03 MPa to 0.6 MPa, under the design conditions. When the supply pressure exceeds 0.8 MPa, the material of the generator, the material of the accessory parts such as piping, and the production method are limited, which is inconvenient in terms of cost. On the other hand, when the supply amount is 0.03 MPa or less, a high-speed flow of the mixed fluid may not be obtained, and the bubble diameter may vary. In addition, the supply amount of the mixed fluid is preferably in the range of 1.5 L to 100 L / min, more preferably in the range of 2 L to 80 L / min, under the design conditions. When the supply amount exceeds 80 L / min, there is a disadvantage that the service life of the generator body is reduced. On the other hand, when the supply amount is less than 2 L / min, a high-speed flow of the mixed fluid cannot be obtained, and the bubble diameter may vary.

(Embodiment 2)
The fine bubble generating apparatus according to the second embodiment will be described with reference to FIG. FIG. 3 is an explanatory diagram showing the inside of the microbubble generator according to the present embodiment.

  The fine bubble generating apparatus 40 according to the present embodiment is provided with guide portions 42 and 44 for guiding the mixed fluid. A spiral channel 46 is formed between the guide portion 42 and the spiral inner wall surface 19, and a circulation channel 47 is formed between the guide portion 44 and the spiral inner wall surface 19. . Further, between the guide portion 42 and the guide portion 44, introduction ports 41 a and 41 b for supplying a mixed fluid to the hollow portion 15 are provided. In addition, an opening 41 c is provided between the guide portion 44 and the spiral inner wall surface 19 to circulate the mixed fluid through the spiral flow path 46 again. The introduction ports 41 a and 41 b and the opening 41 c are provided every 120 degrees with the intersection of the line passing through the central axis of the hollow portion 15 and the center of the supply unit 11 as the center. Moreover, it is preferable that the opening area of introduction port 41a, 41b is the same. On the other hand, the opening area of the opening 41c is preferably smaller than the opening areas of the introduction ports 41a and 41b. Thereby, a venturi effect acts and it can give injection force to the fluid mixture which flows out of opening 41c. The ratio of the opening areas of the introduction ports 41a and 41b and the opening area of the opening 41c is preferably in the range of 6:10 to 7:10. If it exceeds 7:10, the jetting force of the mixed fluid due to the venturi effect may decrease. On the other hand, if it is less than 6:10, the circulating flow of the mixed fluid may be inhibited.

  By providing the opening 41 c and providing the circulation channel 47 in the supply unit 11, the jet force with respect to the mixed fluid and the tensile force due to the flow pressure of the supply unit 11 act on the opening 41, and the spiral channel 46. The flow rate of the mixed fluid flowing through the fluid is accelerated. As a result, the rotational speeds of the gas and the liquid swirling at high speed in the hollow portion 15 can be maintained constant.

  Further, the ratio of the sum of the opening areas of the inlets 41a and 41b and the opening 41c and the opening area of the supply unit 11 is preferably 7:10 to 9:10, and 8.5: 10 to 9: 10 is more preferable. Thus, until the mixed fluid supplied from the supply unit flows through the spiral flow path, the flow velocity and the fluid pressure are continuously increased by the throttling effect and the centrifugal force due to the circular motion. Can do. As a result, the speed of the high-speed swirling flow of the gas and liquid swirling in the hollow portion 15 can be increased by 10 to 20% or more. If it is out of the numerical range, the flow rate itself required for high-speed rotation decreases, which is not preferable.

  Furthermore, in the present embodiment, a gas supply unit 43 may be provided in the vicinity of the opening 41c. Thereby, the flow of the mixed fluid in the opening 41c causes a tensile force to act on the supplied gas. Further, the venturi structure at the opening 41c causes a negative pressure action to act on the gas, allowing the gas to be self-primed. In the present embodiment, an air pump is connected to the gas supply unit 43, so that it can be used in combination with a means for forcibly supplying gas. Further, the gas supply amount can be adjusted by connecting a gas supply pipe to the gas supply unit 43 and further providing a valve on the land portion of the pipe. As a result, the generation amount of fine bubbles can be adjusted, and the supply of gas can be stopped according to the use situation.

(Other matters)
The fine bubble generating apparatus of the present invention is not limited to the above-described embodiments, and various modifications can be made. For example, as shown in FIG. 4, another discharge unit 51 may be provided at a position opposite to the discharge unit 17 of the fine bubble generating device. Thereby, fine bubbles can be generated from both the front part and the rear part of the main body 52.

  Hereinafter, preferred embodiments of the present invention will be described in detail by way of example. However, the materials, blending amounts, and the like described in the examples are not intended to limit the scope of the present invention only to them, but are merely illustrative examples, unless otherwise specified.

Example 1
In this example, the fine bubble generating apparatus shown in FIGS. 1 and 2 described in the above embodiment and made of plastic resin (ABS) was used. This fine bubble generating device was immersed in seawater, and a mixed fluid consisting of natural atmospheric air and seawater (seawater temperature 21.8 ° C.) was supplied to generate fine bubbles consisting of the natural atmospheric air. Furthermore, the time-dependent change of the oxygen dissolution value and oxygen saturation in seawater was measured. The results are shown in Table 1 below.

Note that the micro bubble generating device, 12.6 cm ² and the opening area of the supply unit 11, volume 55.8Cm ³ of the hollow portion 15, 3.2 cm ² of the opening area of the discharge portion 17, inlet 20a and The ratio of the sum of the opening area of the inlet 20b and the opening area of the supply unit 11 was set to 7: 1. The pump pressure was 0.03 MPa, the discharge water amount was 5 L / min, and the seawater amount was 0.8 m ³ .

(Example 2)
In this example, fine bubbles were generated in the same manner as in Example 1 except that a fine bubble generator made of stainless steel (SUS304) was used. Further, in the same manner as in Example 1, changes over time in the oxygen dissolution value and oxygen saturation were measured. The results are shown in Table 1 below.

(Oxygen dissolution value)
The oxygen dissolution rate was measured by a polarographic measurement method.

(Oxygen saturation)
The oxygen saturation was measured by a pulse oximeter method.

It is explanatory drawing showing the microbubble generator which concerns on one Embodiment of this invention, Comprising: The figure (a) represents the inside of a microbubble generator, the figure (b) represents the spiral flow path. It is explanatory drawing which represented typically the behavior of the fluid mixture in the inside of the said microbubble generator, and the generation mechanism of a microbubble. It is explanatory drawing showing the inside of the fine bubble generator which concerns on other embodiment of this invention. It is explanatory drawing showing the inside of the fine bubble generator which concerns on other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fine bubble generator 11 Supply part 12 Guide part 13 Main body 14 Guide part 15 Hollow part 16 Flow path 17 Discharge part 18a, 18b Inlet 19 Spiral inner wall surface 20a, 20b Inlet 21 Negative pressure gas shaft 23 High-speed swirl flow 31 Gap 40 Microbubble generator 41 Opening 41a, 41b Inlet 41c Opening 42 Guide part 43 Gas supply part 44 Guide part 46 Channel 47 Circulating channel 51 Discharge part 52 Main body

Claims (6)

A microbubble generator for generating microbubbles,
A supply unit for supplying a mixed fluid composed of gas and liquid;
A main body having a hollow portion that separates the mixed fluid supplied from the supply portion into a gas and a liquid and forms respective swirling flows;
A discharge section that discharges the gas that has been swirled with the liquid into bubbles;
The main body has a spiral inner wall surface and at least one guide portion that is provided along the spiral inner wall surface and that divides the mixed fluid into the hollow portion by dividing into a plurality of spiral flow paths. And
The spiral inner wall surface causes the mixed fluid supplied from the supply unit to flow spirally so that the spiral surface is perpendicular to the direction of the discharge unit,
The micro-bubble generating device in which the spiral flow path has a throttle structure with respect to the supply unit. Between the guide part and the spiral inner wall surface, and between the guide parts, an introduction port for introducing a mixed fluid to the hollow part is provided, respectively.
2. The fine bubble generating device according to claim 1, wherein a ratio of a sum of opening areas of all the inlets and an opening area of the supply unit is within a range of 7:10 to 9:10. The introduction port provided between the guide portion and the spiral inner wall surface opens in a tangential direction in the spiral surface of the spiral inner wall surface,
The microbubble generator according to claim 2, wherein the inlet provided between the guide portions opens in a tangential direction on the spiral surface of the wall surface of the guide portion.   Between the spiral inner wall surface and the guide portion, there is provided a circulation channel that divides the spiral channel and circulates the mixed fluid, and the opening of the circulation channel is in the vicinity of the supply unit The microbubble generator according to claim 2, wherein the opening area is smaller than the opening area of the inlet.   The microbubble generator according to claim 4, wherein a gas supply unit that supplies the gas is provided in the vicinity of the opening.   The microbubble generator according to any one of claims 1 to 5, wherein a cross-sectional shape of the introduction port is rectangular.

Images