JP5050196B2 - Microbubble generator - Google Patents

Description

  The present invention relates to a microbubble generating device, and more particularly, to a microbubble generating device that generates supply of liquid and air and generates microbubbles in the liquid.

  Conventionally, as this kind of microbubble generator, a cylindrical casing having a small-diameter discharge port formed at the center of one end, and a liquid introduction for supplying water from the other end of the cylindrical casing and swirling the water in the cylindrical casing A path, an intake pipe that introduces air into the central portion of the other end of the cylindrical casing, a gas-liquid guide member that is disposed outside the discharge port of the cylindrical casing and diffuses water mixed with bubbles discharged from the discharge port; Have been proposed (see, for example, Patent Document 1). In this apparatus, air is sucked into a negative pressure portion near the center of the swirling flow in the cylindrical casing, the sucked air is refined by a shearing action by swirling flow, and a liquid mixed with fined bubbles is discharged from the discharge port. It diffuses into water by the gas-liquid induction member.

In addition, a liquid in which air is automatically introduced into the throat using a negative pressure generated by passing high-pressure water through the orifice-shaped throat and a finely mixed liquid is proposed (for example, Patent Document 2). In this apparatus, a collision plate is provided in order to improve the diffusibility of the fine bubbles into the liquid.
JP 2005-34747 A JP 2001-890 A

  In general, it is desirable that the microbubble generator is small, and when the purpose is to increase dissolved oxygen in the liquid, it is desirable that the diameter of the generated bubbles is small. In view of these, in the former apparatus described above, a certain amount of size is required for the cylindrical casing due to the necessity of forming a swirling flow of liquid, and the apparatus becomes large. The latter apparatus is small, but it is desirable that the diameter of the generated bubbles be smaller.

  One object of the microbubble generator of the present invention is to reduce the size. Another object of the microbubble generating apparatus of the present invention is to generate more refined bubbles.

  In order to achieve at least a part of the above-described object, the microbubble generator of the present invention employs the following means.

The first microbubble generator of the present invention is
A microbubble generator for generating microbubbles in a liquid,
For generating microbubbles, comprising: a straight tubular nozzle body having an orifice-shaped throat portion formed therein; and a bubble refinement promoting member that is disposed at a predetermined position downstream of the throat portion and promotes the refinement of bubbles. A nozzle,
A liquid supply means for pressurizing and supplying air-mixed liquid to the microbubble generating nozzle;
It is a summary to provide.

  In this first microbubble generating device of the present invention, when air-mixed liquid is supplied to the nozzle body, the air bubbles supplied by the pressure change in the orifice-shaped throat formed inside are sheared and thinned. . Then, the bubble miniaturization promoting member disposed at a predetermined position on the downstream side of the throat promotes the miniaturization of the bubbles, and discharges the liquid as a mixture of minute bubbles. Thus, by providing the bubble refinement promoting member, the refinement of the bubbles downstream of the throat can be promoted. As a result, it is possible to generate more refined bubbles as compared with the case where no bubble refinement promoting member is provided. Moreover, since only the nozzle body and the bubble miniaturization promoting member are provided, the nozzle can be reduced in size, and the apparatus including this nozzle can be reduced in size.

  In such a first microbubble generating device of the present invention, the bubble miniaturization promoting member may be a plate-like member attached to the most downstream end of the nozzle body. In this case, the bubble miniaturization promoting member may be a member in which a plurality of through holes are formed.

  In the first microbubble generating device of the present invention, the bubble micronization promoting member may be a member having a diffusing function for diffusing a bubble-mixed liquid in the radial direction. In this way, coalescence of the refined bubbles can be suppressed.

  Furthermore, in the first microbubble generating device of the present invention, the bubble miniaturization promoting member may be a member that promotes a pressure increase downstream of the throat portion of the nozzle body. By promoting the pressure increase downstream of the throat, it is possible to further promote the refinement of bubbles.

The second microbubble generator of the present invention is
A microbubble generator for generating microbubbles in a liquid,
A minute nozzle having a straight tubular nozzle body having an orifice-shaped throat portion formed therein, and a pressure increase promoting member that is disposed at a predetermined position downstream of the throat portion and promotes a pressure increase downstream of the throat portion. A bubble generating nozzle;
A liquid supply means for pressurizing and supplying air-mixed liquid to the microbubble generating nozzle;
It is a summary to provide.

  In the second micro-bubble generating device of the present invention, when air-mixed liquid is supplied to the nozzle body, the air bubbles supplied by the pressure change in the orifice-shaped throat formed inside are sheared and thinned. . The pressure increase promoting member disposed at a predetermined position on the downstream side of the throat promotes the increase in the pressure on the downstream side of the throat, thereby promoting the refinement of the bubbles and the liquid in which the fine bubbles are mixed. To release as. Thus, by providing the pressure increase promoting member, it is possible to promote the miniaturization of bubbles downstream of the throat. As a result, it is possible to generate finer bubbles as compared with the case where no pressure increase promoting member is provided. In addition, since only the nozzle main body and the pressure increase promoting member are provided, the nozzle can be reduced in size, and the apparatus including the nozzle can be reduced in size.

  In such a second microbubble generating device of the present invention, the pressure increase promoting member may be a plate-like member attached to the most downstream end of the nozzle body. Further, the pressure increase promoting member may be a member having a diffusion function of diffusing a liquid containing bubbles in the radial direction. In this way, coalescence of the refined bubbles can be suppressed.

  The 1st or 2nd microbubble production | generation apparatus of this invention WHEREIN: It may be arrange | positioned in the upstream of the said throat part of the said nozzle body, and shall be equipped with the swirl | flow flow production | generation member which makes a liquid flow swirl. By so doing, it is possible to promote the refinement of bubbles by making the liquid flow into a swirl flow.

  Further, in the first or second microbubble generator of the present invention, it is also possible to generate bubbles mainly having a diameter of 20 μm or less in the liquid. Here, “the diameter is mainly 20 μm or less” means that, in the present specification, bubbles having a diameter of 20 μm or less are 50% or more.

  Next, the best mode for carrying out the present invention will be described using examples.

  FIG. 1 is a configuration diagram showing an outline of the configuration of a microbubble generating device 20 as an embodiment of the present invention, and FIG. 2 is a sectional view of a microbubble generating nozzle 30 provided in the microbubble generating device 20 of the embodiment. It is sectional drawing which shows an example. As shown in FIG. 1, the microbubble generating device 20 of the embodiment mixes air from a compressor 56 with water from a microbubble generating nozzle 30 disposed in water and water from a water supply pipe 52 and supplies gas and liquid. A gas-liquid mixing pump 50 that pumps the microbubbles to the nozzle 30 through a tube 54.

  The microbubble generating nozzle 30 is formed of a metal material (for example, stainless steel or brass) having excellent corrosiveness and pressure resistance, and has an outer diameter D1, an inner diameter D2, and a length L1, as shown in FIG. A nozzle body 31 is formed as a tubular member, and a bubble miniaturization accelerating / diffusing member 38 as a disk member attached to one end of the nozzle body 31 with a gap L3 by a mounting member 39. Inside the nozzle body 31, an orifice-shaped throat portion 32 having an opening diameter D3 is formed at a position of a length L2 from the attachment end of the bubble miniaturization promoting diffusion member 38. As a specific example of the microbubble generating nozzle 30 of the embodiment, the outer diameter D1 is 40 mm, the inner diameter D2 is 18 mm, the length L1 is 75 mm, the opening diameter D3 of the throat 32 is 8 mm, and the end to the throat. The length L2 up to 32 was 20 mm, the gap L3 was 1.8 mm, and the bubble miniaturization promoting diffusion member 38 had a thickness of 1 mm.

  Next, the operation of the microbubble generator 20 configured as described above, particularly how the microbubbles are generated by the microbubble generating nozzle 30 will be described. When a liquid containing bubbles is pressurized and supplied from an end side different from the bubble miniaturization promoting diffusion member 38 side of the nozzle body 31, the flow rate of the liquid containing bubbles increases at the throat 32, causing a pressure drop. , Bubbles expand. As it passes through the throat 32, the reduced pressure recovers. At this time, energy for collapsing the bubbles (collapse energy) acts on the bubbles, whereby the bubbles are collapsed and miniaturized. This bubble miniaturization is known as bubble miniaturization by cavitation. Since it is considered that such bubble miniaturization is promoted as the bubble collapse energy generated by the pressure increase after passing through the throat portion 32 increases, in the embodiment, at the outflow end of the nozzle body 31 in order to promote the pressure increase. A bubble miniaturization promoting diffusion member 38 is attached. FIG. 3 is an explanatory diagram for explaining the pressure change in the microbubble generating nozzle 30 of the microbubble generating apparatus 20 of the embodiment and the miniaturization of the bubbles. In the figure, the solid line shows the pressure change in the microbubble generating nozzle 30 of the embodiment, and the broken line shows the pressure change in the nozzle body 31 to which the bubble miniaturization promoting diffusion member 38 is not attached as a comparative example. As illustrated, the pressure increase on the downstream side of the throat 32 is larger in the microbubble generating nozzle 30 of the example than in the comparative example.

  The bubble miniaturization promoting diffusion member 38 of the nozzle 30 for generating microbubbles in the embodiment not only increases the pressure increase on the downstream side of the throat portion 32 described above to promote the micronization of the bubbles, but also from the nozzle body 31. The fine bubbles are diffused by diffusing the flow of liquid mixed with bubbles in the lateral direction.

  FIG. 4 is an explanatory diagram showing the distribution of bubble diameters when a water flow rate of 60 l / min and an air flow rate of 2 l / min are supplied to a specific example of the microbubble generator 20 of the above-described embodiment, and FIG. It is explanatory drawing which shows the average diameter of a bubble when changing an air flow rate with the water flow rate of 60 l / min with respect to a specific example. 4 and 5, the black circle mark is a specific example, the square mark is a comparative example, and the triangular mark is a modified example of the specific example, that is, the throat portion 32 of the microbubble generating nozzle 30 of the embodiment. An air introduction hole is provided so that air is automatically introduced and a liquid in which bubbles are not mixed is supplied. As shown in FIG. 4, in the comparative example, bubbles with a diameter of 80 μm or more occupy 50% or more, whereas in the specific example, bubbles with a diameter of 20 μm or less occupy 50% or more. In the modified example, bubbles having a diameter of 40 μm or more occupy 50% or more. Further, as shown in FIG. 5, the average diameter of the bubbles was 22 μm to 35 μm in the specific example, whereas it was 70 μm to 110 μm in the comparative example, and 38 μm to 50 μm in the modified example. ,

  According to the microbubble generating device 20 of the embodiment described above, the diameter of the microbubble generating apparatus 20 is reduced to 20 μm or less by supplying the bubble-mixed liquid to the microbubble generating nozzle 30 including the bubble micronization promoting diffusion member 38. It is possible to generate microbubbles in which bubbles account for 50% or more. Further, since the refined bubbles are diffused by the bubble refinement diffusing member 38, coalescence of the bubbles can be suppressed. Furthermore, since only the bubble miniaturization promoting diffusion member 38 is attached to the nozzle body 31, it is possible to reduce the size of the microbubble generating nozzle 30, and it is possible to reduce the size of the microbubble generating device 20.

  In the microbubble generating device 20 of the embodiment, as one specific example of the microbubble generating nozzle 30, the outer diameter D1 is 40 mm, the inner diameter D2 is 18 mm, the length L1 is 75 mm, the opening diameter D3 of the throat 32 is 8 mm, and the end. The length L2 from the head portion to the throat portion 32 is 20 mm, the gap L3 is 1.8 mm, and the thickness of the bubble miniaturization accelerating diffusion member 38 is 1 mm. However, the present invention is not limited to such a specific example. It is good also as what uses the nozzle 30 for microbubble production | generation of a dimension.

  In the microbubble generating device 20 of the embodiment, the throat portion 32 is only formed inside the nozzle body 31, but a swirl flow is generated as shown in the microbubble generating nozzle 30B of the modified example of FIG. The turning vane 37 may be attached.

  In the microbubble generating device 20 of the embodiment, the bubble miniaturization promoting diffusion member 38 as a disk member is attached to the end of the nozzle body 31 to constitute the microbubble generating nozzle 30. The diffusing member 38 does not have to be a disk member, and a rectangular member or the like may be used. Further, as shown in the bubble miniaturization promoting diffusion member 238 of the modification of FIG. 7, a member in which a plurality of through holes 240 are formed may be used.

  In the microbubble generating device 20 of the embodiment, the microbubble generating nozzle 30 is configured by attaching the bubble miniaturization accelerating diffusion member 38 as a disk member to the end of the nozzle body 31. As shown in the example microbubble generating nozzle 330, a microbubble generating nozzle 330 is attached by attaching a bubble miniaturization accelerating diffusion member 338 such as a disk member or a rectangular member to the downstream side of the throat 332 of the nozzle body 331. It is good also as what comprises.

  The best mode for carrying out the present invention has been described with reference to the embodiments. However, the present invention is not limited to these embodiments, and various modifications can be made without departing from the gist of the present invention. Of course, it can be implemented in the form.

  The present invention can be used in the manufacturing industry of microbubble generators.

It is a block diagram which shows the outline of a structure of the microbubble production | generation apparatus 20 as one Example of this invention. 4 is a cross-sectional view showing an example of a cross-sectional shape of a microbubble generating nozzle 30. FIG. It is explanatory drawing for demonstrating the pressure change in the nozzle 30 for microbubble production | generation, and refinement | miniaturization of a bubble. It is explanatory drawing which shows distribution of the diameter of a bubble when the water flow rate of 60 l / min and the air flow rate of 2 l / min are supplied with respect to the specific example of the microbubble production | generation apparatus 20. FIG. It is explanatory drawing which shows the average diameter of a bubble when changing an air flow rate with the water flow rate of 60 l / min with respect to the specific example of the microbubble production | generation apparatus 20. FIG. It is sectional drawing which shows an example of the cross-sectional shape of the nozzle 30B for microbubble production | generation of a modification. It is a block diagram which shows an example of a structure of the bubble miniaturization acceleration | stimulation diffusion member 238 of a modification. It is sectional drawing which shows an example of the cross-sectional shape of the nozzle 330 for microbubble production | generation of a modification.

Explanation of symbols

20 Microbubble generating device, 30, 30B, 330 Microbubble generating nozzle, 31,331 Nozzle body, 32,332 Throat, 37 Swivel vane, 38,238,338 Bubble miniaturization promoting diffusion member, 39 Mounting member, 50 Gas-liquid mixing pump, 52 water supply pipe, 54 gas-liquid supply pipe.

Claims (10)

A microbubble generator for generating microbubbles in a liquid,
For generating microbubbles, comprising: a straight tubular nozzle body having an orifice-shaped throat portion formed therein; and a bubble refinement promoting member that is disposed at a predetermined position downstream of the throat portion and promotes the refinement of bubbles. A nozzle,
A liquid supply means for pressurizing and supplying air-mixed liquid to the microbubble generating nozzle;
A microbubble generator comprising:   The microbubble generator according to claim 1, wherein the bubble miniaturization promoting member is a plate-like member attached to the most downstream end of the nozzle body.   The microbubble generating apparatus according to claim 2, wherein the bubble miniaturization promoting member is a member in which a plurality of through holes are formed.   The microbubble generating device according to any one of claims 1 to 3, wherein the bubble miniaturization promoting member is a member having a diffusion function of diffusing a liquid containing bubbles in a radial direction.   The microbubble generating device according to any one of claims 1 to 4, wherein the bubble miniaturization promoting member is a member that promotes a pressure increase downstream of the throat portion of the nozzle body. A microbubble generator for generating microbubbles in a liquid,
A minute nozzle having a straight tubular nozzle body having an orifice-shaped throat portion formed therein, and a pressure increase promoting member that is disposed at a predetermined position downstream of the throat portion and promotes a pressure increase downstream of the throat portion. A bubble generating nozzle;
A liquid supply means for pressurizing and supplying air-mixed liquid to the microbubble generating nozzle;
A microbubble generator comprising:   The microbubble generator according to claim 6, wherein the pressure increase promoting member is a plate-like member attached to the most downstream end of the nozzle body.   The microbubble generating device according to claim 6 or 7, wherein the pressure increase promoting member is a member having a diffusion function of diffusing a liquid mixed with bubbles in a radial direction.   The microbubble generator according to any one of claims 1 to 8, further comprising a swirl flow generating member that is disposed upstream of the throat portion of the nozzle body and uses a liquid flow as a swirl flow. The microbubble generator according to any one of claims 1 to 9, which generates bubbles having a diameter of mainly 20 µm or less in a liquid.

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