JP2008132437A - Microbubble generation apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a microbubble generation apparatus capable of generating very fine bubbles independently of the pressure of a gas to be supplied or flow rate of a liquid. <P>SOLUTION: The microbubble generation apparatus comprises a porous body 8 having a plurality of bubble releasing holes for releasing bubbles which are arranged regularly or irregularly in a bubble releasing face 8b forming an interface with a liquid, a main body casing 9 for holding the porous body 8 and an impeller part 10, a gas chamber 11 communicating with bubble releasing holes, a gas supply pipeline 7 for supplying a gas to the gas chamber 11, and a submerged motor apparatus 4 for moving the porous body 8 relatively to the liquid generating convection current of the liquid on the bubble releasing face 8b. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a microbubble generator, and relates to a technique for mixing microbubbles in a liquid.

  Conventionally, as a method of mixing fine bubbles in a liquid, for example, as described in Patent Document 1, a gas such as ozone is sent into a ceramic cylinder at a high pressure, and bubbles are formed from the ceramic holes as external water. There is something that is sent to the liquid and dissolved. However, there is a problem that the gas pressure has to be increased as the pore diameter of the ceramic is reduced for the purpose of reducing the bubble diameter.

  For this reason, Patent Document 1 discloses a configuration that does not depend on the gas pressure but depends on the force of the liquid vortex. That is, an outer cylinder is concentrically arranged outside the ceramic cylinder, a narrow flow path is formed between the ceramic cylinder and the outer cylinder, and a liquid is allowed to flow through the flow path at a high speed so as to exceed the critical Reynolds number. The surface tension of bubbles is broken by fine vortices generated by the turbulent flow of gas, and fine bubbles of gas are continuously dissolved in the liquid. Further, as a configuration for further strengthening the vortex of the liquid, spiral fine irregularities are formed on the inner surface of the outer cylinder arranged outside the ceramic cylinder.

  Patent Document 2 describes a microbubble generator, a polluted water purifier, and a polluted water purifying method. This bubble generating device is provided in a liquid and includes a stirring fin and a supply pipe for supplying air. One end of the supply pipe opens as a supply port at the center of the stirring fin, and the other end of the supply pipe Is opened to the gas supply source as an intake hole. Then, a negative pressure is generated around the stirring fin while the surrounding liquid is stirred by the rotation of the stirring fin, and a gas is sucked from the supply pipe by this negative pressure to generate bubbles.

A baffle plate made of a plate-like body is provided on the outside of the rotating stirring fin, and a plurality of baffle plates are erected so as to disturb the stirring of the liquid by the stirring fin, and the baffle plates are connected and fixed with a fixed plate. The stirring fin is included, and a perforated plate is provided outside the stirring fin in the radial direction. The gas sucked from the supply port is finely divided by the stirring fin, the perforated plate, and the baffle plate and supplied to the liquid.
WO2002 / 036252 JP 2006-82072 A

  By the way, in Patent Document 1, an outer cylinder is arranged concentrically outside the ceramic cylinder, a narrow flow path is formed between the ceramic cylinder and the outer cylinder, and a liquid is allowed to flow through the flow path at a high speed. In the case where there is a narrow channel between the ceramic cylinder and the outer cylinder, the flow rate of the liquid that can be supplied through this channel is limited. When the flow paths of the ceramic cylinder and the outer cylinder are enlarged so that a large amount of liquid can be supplied, it is necessary to increase the pump power in order to supply a large amount of liquid at a flow rate necessary for generating vortices.

  Moreover, even when a spiral fine uneven portion is formed on the inner surface of the outer cylinder, if the distance between the uneven portion and the ceramic cylinder that discharges the bubbles is increased, the vortex action hardly reaches the surface from which the bubbles are discharged. In addition, as described in Patent Document 2, when the gas sucked from the supply port is finely divided by the stirring fin, the perforated plate and the baffle plate and supplied into the liquid, the original gas sucked from the supply port is supplied. Since the bubble diameter is large, there is a limit to the refinement of bubbles that can be achieved by transient collisions with stirring fins, perforated plates, and baffle plates.

  The present invention solves the above-described problems, and an object of the present invention is to provide a fine bubble generating device that can generate fine bubbles without depending on the pressure of a supplied gas and the flow rate of a liquid.

  In order to solve the above-mentioned problems, a microbubble generator according to the present invention holds a bubble emitter having a plurality of bubble discharge holes for releasing bubbles on a bubble release surface that forms an interface with a liquid, and the bubble emitter. A discharge body holding means, a gas chamber communicating with the bubble discharge hole, a gas supply means for supplying a gas to the gas chamber, a bubble discharge body is moved relative to the liquid, and the liquid is placed on the bubble discharge surface. And a relative driving means for generating a relative flow, and a turbulence promoting means for generating a turbulent flow in the relative flow of the liquid is disposed on the bubble discharge surface.

Further, the turbulent flow promoting means forms a low pressure region on the bubble discharge surface that forms a pressure lower than the surrounding average fluid pressure.
Further, the turbulent flow promoting means comprises a protrusion-like body projecting into the relative flow of liquid from the emitter holding means or the bubble emitter.

Further, the relative drive means is composed of a rotational drive device for rotationally driving the bubble emitter around the axis of the drive shaft.
In addition, the bubble emitter is cylindrical or plate-like, and the protrusions of the turbulence promoting means are composed of blades arranged radially around the rotation axis of the bubble emitter.

Further, the relative drive means is composed of a pump device for supplying a liquid along the bubble discharge surface.
Further, the bubble emitting body is cylindrical, and the turbulent flow promoting means is a spiral protrusion or a plurality of annular protrusions.

  Further, the bubble emitting body is made of a carbon material, a ceramic porous body, or a sintered metal.

  As described above, according to the present invention, the bubble emitter is moved with respect to the liquid by the relative driving means to generate a relative flow of the liquid on the bubble discharge surface. The gas supplied to the gas chamber by the gas supply means is ejected into the liquid from the bubble discharge surface that forms an interface with the liquid through the bubble discharge hole. At this time, the bubble discharge surface moves relative to the liquid, so that the gas ejected from the bubble discharge surface into the liquid is ejected as fine bubbles, and turbulent flow is arranged on the bubble discharge surface. By the means, a turbulent flow can be reliably applied to the gas ejected from the bubble discharge hole.

  In the present invention, when the bubbles are ejected from the bubble ejection holes, the bubbles already have a fine bubble diameter, and the turbulence promoting means ensures that the turbulent flow acts on the bubble ejection surface and discharges the ejected fine bubbles to the bubbles. It is made to dissipate quickly from the vicinity of the hole and suppress the coalescence of bubbles. Therefore, fine bubbles can be generated without depending on the pressure of the supplied gas and the flow rate of the liquid.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the fine bubble generating device 1 of the present embodiment is a case where it is placed in water such as a water tank or a water channel, and rotates as a relative driving means on a leg 3 placed on a bottom wall surface 2. An underwater motor device 4 is provided as a driving device. The rotation drive device is not limited to the submersible motor device 4, and an engine device or the like can be used as appropriate. A bubble discharge unit 6 is connected to the drive shaft 5 of the submersible motor device 4, and the bubble discharge unit 6 is rotatably connected to an air supply line 7 as a gas supply means. The air supply line 7 is connected to an air supply source. In the present embodiment, the liquid is water and the gas is air. However, the present invention is not limited to water and air.

  Further, the fine bubble generating device 1 can be installed outside the water tank as shown in FIG. 9, and when installed in the water tank as shown in FIG. A structure in which the path 7 penetrates the underwater motor device 4 and is connected to the bubble discharge unit 6 is also possible.

  As shown in FIGS. 2-6, the bubble discharge | release part 6 is provided with the main body casing 9 and the blade | wing part 10 which make | form the porous body 8 which makes a bubble discharge body, and discharge body holding means. Although the porous body 8 of the present embodiment is made of a carbon material, ceramic or sintered metal can be used for the bubble emitter, or a porous film may be used.

  As shown in FIG. 5, the porous body 8 has a plate shape, and here, a circular hole is formed in the center, and a vent hole 8 a is formed at the center. Bubbles are formed on the bubble discharge surface 8 b that forms an interface with water. A plurality of bubble discharge holes to be discharged are arranged regularly or irregularly. This bubble discharge hole is configured so that fine bubbles can be ejected by setting it to a minute predetermined diameter corresponding to the bubble diameter of the air discharged into the water. In the present embodiment, the bubble diameter is several tens of μm, the diameter of the bubble discharge hole is 0.4 to 5 μm, the porous body 8 has a porosity of 12 to 35%, and its maximum use pressure is 0.6 MPa. .

  As shown in FIG. 4, the main body casing 9 has a coupling hole 9 a and a key groove 9 b for connecting to the drive shaft 5 of the submersible motor device 4, and a recess formed inside forms a gas chamber 11. The porous body 8 is held between the blade portion 10 on the opening side of 11. Spacers 12 for maintaining a gap with the porous body 8 are radially formed around the coupling hole 9 a inside the main body casing 9. The gas chamber 11 communicates with the bubble discharge hole of the porous body 8, and the air supply conduit 7 communicates with the gas chamber 11 via the blade portion 10.

  As shown in FIG. 6, the blade portion 10 is arranged radially around the hub 15, a flange 14 for fixing to the main body casing 9 with bolts 13, a hub 15 for connection to the air supply pipe 7, and the hub 15. It consists of a plurality of blades 16 that form turbulent flow promoting means.

  Each blade 16 is located on the surface of the bubble discharge surface 8b of the porous body 8 and forms a protrusion that protrudes from the bubble discharge surface 8b into the relative flow of water, and is porous at the opening 10a between the blades 16. The bubble discharge surface 8b of the material 8 is exposed. At this time, the blade 16 and the bubble discharge surface 8b do not necessarily need to be in close contact with each other, and a predetermined effect can be obtained even if there is a small gap.

The hub 15 has a connection hole 15 a rotatably connected to the air supply pipe line 7 through a shaft seal 17.
With this configuration, the submersible motor device 4 serving as a relative drive means rotates the bubble discharge portion 6 around the axis of the drive shaft 5 by the rotation of the drive shaft 5, and the porous body 8 is relative to the water in water. And a relative flow of water is generated on the surface of the bubble discharge surface 8b.

  The air that has flowed into the gas chamber 11 from the air supply pipe 7 passes through the bubble discharge holes of the porous body 8 and is ejected as microbubbles onto the surface of the bubble discharge surface 8b that forms an interface with water, and the bubble discharge surface 8b. As the water moves in the water, the relative flow flowing along with the vortex on the surface of the bubble discharge surface 8b entrains and separates the microbubbles and suppresses the coalescence of the bubbles.

  As the relative driving means, as will be described later, it is possible to adopt a pump device that supplies water along the bubble discharge surface 8b. However, a motor device is adopted as the relative driving means, and the porous structure forming the bubble emitting body is adopted. When the material 8 is rotationally driven, fine bubbles can be generated with less power than when the pump device is employed even when the amount of target liquid is large.

  The blade portion 10 that rotates integrally with the porous body 8 sucks water below by the hydraulic action of the blade 16 and diffuses bubbles to the surroundings. Then, as shown in FIG. 7, the blade 16 disturbs the flow of the relative flow on the surface of the bubble discharge surface 8b, and the turbulent flow with the vortex flow is surely generated on the surface of the bubble discharge surface 8b. A turbulent flow can be reliably applied to the air ejected from the discharge hole. In addition, a low pressure region having a pressure lower than the surrounding average fluid pressure is formed on the surface of the bubble discharge surface 8b on the downstream side of the blade 16 in the rotation direction of the blade portion 10. Under the action of this low pressure, air is easily ejected from the bubble discharge hole, resulting in finer bubbles.

  In the present embodiment, the porous body 8 is formed in a disk shape, and the bubble discharge surface 8b of the porous body 8 is exposed between the blades 16. However, as another embodiment of the present invention, As shown in FIG. 8, you may arrange | position the bubble discharge | release surface 8b of the porous body 8 in the downstream side surface of the blade | wing 16 which is a protrusion-like body in the flow direction of the relative flow of water. In this case, the blade portion 10 has a narrow opening 10 a in the downstream region of the blade 16, and the plate-like porous body 8 is arranged and held in parallel with the blade 16 in the opening 10 a.

  With this configuration, a low pressure region having a pressure lower than the surrounding average fluid pressure is formed on the surface of the bubble discharge surface 8b on the downstream side of the blade 16 in the rotation direction of the blade portion 10, and on the surface of the bubble discharge surface 8b. A turbulent flow with a vortex flow is surely generated, and the turbulent flow surely acts on the air ejected from the bubble discharge hole, and the air is ejected as fine bubbles from the bubble discharge hole.

  As another embodiment of the present invention, as shown in FIG. 11, the main body casing 9 and the porous body 8 are formed in a cylindrical shape, and through another means (not shown) for holding the porous body 8. It is also possible to arrange both of them concentrically, form a water channel 18 between the main body casing 9 and the porous body 8, and form the gas chamber 11 inside the porous body 8. The porous body 8 has a spline shape, and on the outer peripheral surface thereof, blades 16 forming protrusions protruding into water are formed radially around the axis of the porous body 8, and each blade 16 is a porous body. 8 linearly extends in the axial direction.

  In this case, water is supplied to the water channel 18 in a state where the porous body 8 is rotationally driven around the axis, and air is supplied to the gas chamber 11. The air in the gas chamber 11 is ejected as microbubbles through the bubble discharge hole of the porous body 8 onto the surface of the bubble discharge surface 8b that forms an interface with water, and the bubble discharge surface 8b moves through the water to release the bubble. The relative flow flowing along the vortex on the surface 8b entrains and separates the microbubbles.

  The vane 16 rotating integrally with the porous body 8 disturbs the flow of the relative flow on the surface of the bubble discharge surface 8b, and reliably generates a turbulent flow with a vortex on the surface of the bubble discharge surface 8b. A turbulent flow is surely applied to the air ejected from the air.

  A low pressure region having a pressure lower than the surrounding average fluid pressure is formed on the bubble discharge surface 8 b on the downstream side of the blade 16 in the rotation direction of the blade 16. The air ejected from the bubble discharge hole under this low pressure action becomes finer bubbles.

  As another embodiment of the present invention, as shown in FIG. 12, the main body casing 9 and the porous body 8 are formed in a cylindrical shape, and through another means (not shown) for holding the porous body 8. Both can be arranged concentrically, the gas chamber 11 can be formed between the main body casing 9 and the porous body 8, and the water channel 18 can be formed inside the porous body 8. The porous body 8 has a spline shape, and on its inner peripheral surface, blades 16 that form protrusions protruding into water are formed radially around the axis of the porous body 8, and each blade 16 is porous. It extends linearly in the axial direction of the body 8.

  In this case, water is supplied to the water channel 18 in a state where the porous body 8 is rotationally driven around the axis, and air is supplied to the gas chamber 11. The air in the gas chamber 11 is ejected as microbubbles through the bubble discharge hole of the porous body 8 onto the surface of the bubble discharge surface 8b that forms an interface with water, and the bubble discharge surface 8b moves through the water to release the bubble. The relative flow flowing along the vortex on the surface 8b entrains and separates the microbubbles.

  The vane 16 rotating integrally with the porous body 8 disturbs the flow of the relative flow on the surface of the bubble discharge surface 8b, and reliably generates a turbulent flow with a vortex on the surface of the bubble discharge surface 8b. A turbulent flow is surely applied to the air ejected from the air.

  A low pressure region having a pressure lower than the surrounding average fluid pressure is formed on the bubble discharge surface 8 b on the downstream side of the blade 16 in the rotation direction of the blade 16. The air ejected from the bubble discharge hole under this low pressure action becomes finer bubbles.

  As other embodiment of this invention, as shown in FIG. 13, the main body casing 9 and the porous body 8 that form the emitter holding means are formed in a cylindrical shape, and both are fixedly arranged concentrically, It is also possible to form a water channel 18 between the main body casing 9 and the porous body 8 and form the gas chamber 11 inside the porous body 8. In the porous body 8, a plurality of protrusions 19 projecting into water on the outer peripheral surface are formed in an annular shape around the axis of the porous body 8, and the protrusions 19 are along the axial direction of the porous body 8. Are arranged at a predetermined pitch. The protruding body 19 can also be formed in a spiral shape.

  In this configuration, a relative driving means and a pump device that generate a relative flow on the surface of the bubble discharge surface 8b of the porous body 8 are employed. Water is supplied to the water channel 18 by the pump device, and air is supplied to the gas chamber 11 in a state where the water flows along the bubble discharge surface 8b. The air in the gas chamber 11 is ejected as microbubbles through the bubble discharge hole of the porous body 8 onto the surface of the bubble discharge surface 8b that forms an interface with water, and flows on the surface of the bubble discharge surface 8b with a vortex. The relative flow entrains and separates microbubbles.

  The protruding body 19 of the porous body 8 disturbs the flow of the relative flow on the surface of the bubble discharge surface 8b, and the turbulent flow with the vortex is surely generated on the surface of the bubble discharge surface 8b. The turbulent flow is surely applied to the air.

  A low pressure region having a pressure lower than the surrounding average fluid pressure is formed on the bubble discharge surface 8b on the downstream side of the protrusion 19. The air ejected from the bubble discharge hole under this low pressure action becomes finer bubbles.

  As other embodiment of this invention, as shown in FIG. 14, the main body casing 9 and the porous body 8 which constitute the emitter holding means are formed in a cylindrical shape, and both are fixedly arranged concentrically. It is also possible to form the gas chamber 11 between the main body casing 9 and the porous body 8 and form the water channel 18 inside the porous body 8. In the porous body 8, a plurality of protrusions 19 projecting into water on the inner peripheral surface are formed in an annular shape around the axis of the porous body 8, and the protrusions 19 are arranged in the axial direction of the porous body 8. Are arranged at a predetermined pitch. The protruding body 19 can also be formed in a spiral shape. Further, as shown in FIG. 15, the annular protrusions 19 may be attached to the main casing 9 by being connected to each other by rod-like members 20. At this time, it is not always necessary that the annular protrusion and the bubble discharge surface are in close contact with each other, and a predetermined effect can be obtained even if there is a minute gap.

  In the configuration described above, a relative driving means and a pump device that generate a relative flow on the surface of the bubble discharge surface 8b of the porous body 8 are employed. Water is supplied to the water channel 18 by the pump device, and air is supplied to the gas chamber 11 in a state where the water flows along the bubble discharge surface 8b. The air in the gas chamber 11 is ejected as microbubbles through the bubble discharge hole of the porous body 8 onto the surface of the bubble discharge surface 8b that forms an interface with water, and flows on the surface of the bubble discharge surface 8b with a vortex. The relative flow entrains and separates microbubbles.

  The protruding body 19 of the porous body 8 disturbs the flow of the relative flow on the surface of the bubble discharge surface 8b, and the turbulent flow with the vortex is surely generated on the surface of the bubble discharge surface 8b. The turbulent flow is surely applied to the air.

  A low pressure region having a pressure lower than the surrounding average fluid pressure is formed on the bubble discharge surface 8b on the downstream side of the protrusion 19. The air ejected from the bubble discharge hole under this low pressure action becomes finer bubbles.

  In the above-described embodiment, the example in which the protruding body is used as the turbulent flow promoting means has been described. However, the embodiment is not limited to the protruding body, and a groove may be provided on the bubble discharge surface. .

The front view which shows the microbubble generator in embodiment of this invention Sectional drawing which shows the bubble discharge | release part in the same embodiment The top view which shows the bubble discharge | release part in the same embodiment (A) is a top view which shows the main body casing in the embodiment, (b) is AB sectional view taken on the line in (a). (A) is sectional drawing which shows the porous body in the embodiment, (b) is a top view which shows the porous body in the embodiment (A) is sectional drawing which shows the blade | wing part in the same embodiment, (b) is a top view which shows the blade | wing part in the same embodiment Schematic diagram showing the operation in the same embodiment Schematic diagram showing the operation in another embodiment The front view which shows the microbubble generator in other embodiment The front view which shows the microbubble generator in other embodiment Sectional drawing which shows the microbubble generator in other embodiment Sectional drawing which shows the microbubble generator in other embodiment Sectional drawing which shows the microbubble generator in other embodiment Sectional drawing which shows the microbubble generator in other embodiment Sectional drawing which shows the microbubble generator in other embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fine bubble generator 2 Bottom wall surface 3 Leg part 4 Submersible motor device 5 Drive shaft 6 Bubble discharge part 7 Air supply line 8 Porous body 8a Vent hole 8b Bubble discharge surface 9 Main body casing 9a Bonding hole 9b Key groove 10 Blade part DESCRIPTION OF SYMBOLS 10a Opening 11 Gas chamber 12 Spacer 13 Bolt 14 Flange 15 Hub 15a Connecting hole 16 Blade 17 Shaft seal 18 Water channel 19 Projection body 20 Rod-shaped member

Claims (8)

A bubble emitting body in which a plurality of bubble emitting holes for emitting bubbles are arranged on a bubble emitting surface forming an interface with the liquid, an emitter holding means for holding the bubble emitting body, a gas chamber communicating with the bubble emitting hole, A gas supply means for supplying gas to the gas chamber; and a relative drive means for moving the bubble emitter relative to the liquid to generate a relative flow of the liquid on the bubble discharge surface. A turbulent flow promoting means for generating turbulent flow is disposed on a bubble discharge surface. 2. The fine bubble generating device according to claim 1, wherein the turbulent flow promoting means forms a low-pressure region on the bubble discharge surface that has a pressure lower than the surrounding average fluid pressure. 3. The fine bubble generating apparatus according to claim 1, wherein the turbulent flow promoting means comprises a protrusion-like body protruding into the relative flow of liquid from the discharge body holding means or the bubble discharge body. 4. The fine bubble generating device according to claim 3, wherein the relative drive means comprises a rotation drive device that rotationally drives the bubble emitter around the axis of the drive shaft. 5. The fine bubble according to claim 4, wherein the bubble emitting body has a cylindrical shape or a plate shape, and the protrusions of the turbulence promoting means are composed of blades arranged radially around the rotation axis of the bubble emitting body. Generator. 4. The fine bubble generating apparatus according to claim 3, wherein the relative driving means comprises a pump device for supplying a liquid along the bubble discharge surface. 7. The fine bubble generating device according to claim 6, wherein the bubble emitting body has a cylindrical shape, and the turbulence promoting means is a spiral protrusion or a plurality of annular protrusions. The microbubble generator according to any one of claims 1 to 7, wherein the bubble emitter is made of a carbon material, a ceramic porous body, or a sintered metal.

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