JP7655837B2 - Microbubble generator - Google Patents

Description

The present invention relates to a microbubble generating device, and in particular to a device that generates microbubbles by rotating a disk in a liquid phase.

Microbubbles are tiny bubbles with a diameter of 100 μm or less (e.g., several tens of μm to several μm), and are also called fine bubbles, microbubbles, nanobubbles, etc. For example, water quality can be improved by supplying microbubbles containing trapped air into water and dissolving them. It has also been reported that water containing microbubbles has an activating effect on microorganisms, plants, and animals, and microbubbles can be used to increase crop yields, for example. Furthermore, microbubbles containing various gases (oxygen, ozone, nitrogen, etc.) are also used in the fields of medicine and food, and it has been reported that microbubbles containing ozone gas, for example, have a strong bactericidal effect (see Non-Patent Document 1).

One example of a method for generating micro-bubbles is the ejector method, in which a liquid is passed through a small-diameter pipe at high speed, and the negative pressure generated by the liquid flow is used to draw in gas into the liquid, and the cavitation generated downstream breaks up the gas, creating micro-bubbles (see Patent Documents 1 to 3 and Non-Patent Document 2). However, conventional ejector-type micro-bubble generation methods require the gas to be pressurized using a pump or the like, and require a relatively large amount of energy to generate the micro-bubbles, making them difficult to apply to the ocean or fish farms where there is no power source.

In response to this, a disk-type microbubble generator 50 has been proposed that can generate microbubbles with relatively little energy, as shown in Figure 4 (see Patent Document 4). The illustrated example of the microbubble generator 50 includes a disk 51 with multiple hollow ducts (hollow pipes) 60 attached radially on one side and an airtight chamber 55 on the other side, a hollow rotating shaft pipe 70 inserted into the center of the disk 51 and one end of which is connected to the airtight chamber 55, and a drive unit 80 that rotates the disk 51 around the pipe 70 (see Figure 4 (A)).

The disk 51 in the illustrated example is composed of a circular substrate 52 of a predetermined diameter R0 (see FIG. 4C), a doughnut-shaped substrate 61 (see FIG. 4D) with a central hole 62 of the same diameter aligned and facing one side of the circular substrate 52 (the lower side in the illustrated example), a plurality of hollow ducts 60 (see FIG. 4D) of length L2 radially arranged at a required angular interval θ in the opposing gap between the circular substrate 52 and the doughnut-shaped substrate 61, and an airtight chamber 55 (see FIG. 4A) that airtightly covers the opposite side of the circular substrate 52 (the upper side in the illustrated example). As shown in FIG. 4D, in the central part of the disk 51 surrounded by the plurality of hollow ducts 20, a central gap 63 of a predetermined diameter (=R0-L2) is formed that is connected to the central hole 62 of the doughnut-shaped substrate 61. As shown in FIG. 4(C), multiple minute through holes 56 that connect to the hollow portions of each hollow pipe 60 are drilled in the circular substrate 52 at the required angular interval θ.

As shown in FIG. 4(E), which is a cross-sectional view of FIG. 4(A), the airtight chamber 55 of the disk 51 can be formed, for example, by aligning a circular substrate 53 (see FIG. 4(B)) of the same diameter with the opposite side (upper side) of the circular substrate 52 and sealing the peripheral portion of the opposing gap between the pair of circular substrates 52 and 53 with a sealant 54. As shown in FIG. 4(A), an intake hole 71 and an exhaust hole 73 are provided at one end and the other end of a hollow rotating shaft pipe 70, and one end of the pipe is inserted and fixed in the center of the disk 51 to connect the exhaust hole 73 to the airtight chamber 55, and the other end is exposed above the liquid surface to connect the intake hole 71 to the gas phase Pa. The drive shaft 81 of the drive unit 80 is connected to the other end of the pipe 70 exposed above the liquid surface. The reference numeral 82 in the figure indicates a coupling that connects the other end of the pipe 70 to the drive shaft 81 of the drive unit 80.

When the disk 51 is immersed in the liquid phase as shown in FIG. 4(A) and rotated around the pipe 70 at the required rotational speed ω by the drive unit 80 protruding above the liquid surface, the liquid Q flows from the central gap 63 of the disk 51 into each hollow duct 60 due to the centrifugal force F generated during rotation as shown in FIG. 4(E), and a liquid flow at the required speed flowing from the center of the disk 51 to the outer periphery is formed in the hollow portion of each hollow duct 60. In addition, the liquid flow sucks gas G from the airtight chamber 53 of the disk 51 through the minute through holes 56 into each hollow duct 60 and mixes with the liquid Q. Although the pressure of the airtight chamber 55 decreases due to the sucking of gas G, gas G is replenished from the gas phase Pa to the airtight chamber 55 through the pipe 70. The intake hole 71 of the pipe 70 is provided with an intake amount adjustment plug 72, which allows the flow rate of the intake gas G to be adjusted.

As shown in Figures 5(A) and (B), each hollow pipe 60 of the disk 51 functions in the same way as a conventional ejector. That is, negative pressure is generated by the liquid flow passing through the relatively narrow hollow pipe 60 from the relatively wide central gap 63 of the disk 51, and the gas G is sucked from the airtight chamber 55 into each hollow pipe 60 by the negative pressure and mixed with the liquid Q. The mixed gas G is crushed by cavitation in the process of being sent to the pipe outlet 60a together with the liquid Q, and is released into the liquid phase Pb from the outer periphery of the disk into the liquid phase Pb. In this way, the fine bubble generator 50 of Figure 4 can efficiently generate fine bubbles S using only the driving energy of the rotation of the relatively small disk 51, and does not require the use of a device such as a pump to pressurize the liquid Q, so it can be easily applied on the ocean or in fish farms where there is no power source.

JP 2005-334869 A JP 2006-167612 A JP 2019-147086 A JP 2019-034292 A

Shozo Himuro, "Finance of Fine Bubbles and Their Applications," Science Materials No. 80, Jikkyo Publishing, September 26, 2016, Internet <http://www.jikkyo.co.jp/download/detail/45/9992657592> "Introduction to Fine Bubbles, Chapter 6: Fine Bubble Generation Technology," edited by the Fine Bubble Society of Japan, written by Koichi Terasaka et al., Nikkan Kogyo Shimbun, published November 28, 2016, pp. 167-192

The conventional micro-bubble generator 50 shown in Figure 4 can adjust the particle size and amount (concentration) of the generated micro-bubbles S by adjusting the amount of gas G taken in from the intake hole 71 of the hollow rotating shaft pipe 70 (intake amount adjustment plug 72). However, the hollow rotating shaft pipe 70 functions not only as a flow path for taking in gas G into the airtight chamber 55 but also as the rotation axis of the disk 51, and the position of the intake hole 71 varies according to the rotation of the disk 51. Therefore, it is difficult to operate the intake amount adjustment plug 72 of the intake hole 71 unless the rotation of the disk 51 is stopped, and there is a problem that the amount of gas G taken in cannot be finely adjusted steplessly while generating the micro-bubbles S.

In addition, in the conventional micro-bubble generator 50, the position of the intake hole 71 that takes in gas G when generating micro-bubbles varies according to the rotation of the disk 51. Although it is possible to open the intake hole 71 to the atmosphere, it is difficult to connect supply ports for various gases (oxygen, ozone, nitrogen, etc.) to the intake hole 71, and there is a problem that micro-bubbles containing such gases cannot be generated. As mentioned above, the use of micro-bubbles containing various gases is progressing, and there is a demand for the development of technology that can easily generate such micro-bubbles with relatively little energy.

The object of the present invention is to provide a microbubble generator that can fix the gas intake position when generating microbubbles.

1 and 2, the microbubble generating device according to the present invention comprises a circular disk 10 (see FIG. 1D) having a central groove 11 at the center and a plurality of radial grooves 12 extending from the central groove 11 to the periphery on the lower surface 10u, which is immersed in liquid Pb , a doughnut-shaped cover plate 14 (see FIGS. 2B and 2E) which covers the part of the lower surface 10u of the circular disk 10 other than the central groove 11, a drive unit 25 (see FIG. 1A) which rotates the circular disk 10 around its central axis, and a drive unit 26 (see FIG. 1B) for driving the circular disk 10. The device is equipped with an intake pipe 30 (see FIG. 1(A)) having one end 32 facing the central groove 11 of the underside 10u and the other end 31 communicating with the gas phase Pa . Negative pressure is generated in the central groove 11 by rotating the circular disk 10 by the drive unit 25, and the gas G sucked in from the one end 32 of the intake pipe 30 by the negative pressure is mixed with the liquid Q and caused to flow into each radial groove 12 covered with a donut-shaped cover plate 14 , and the air bubbles S crushed in each radial groove 12 are released from the periphery of the circular disk 10 (see FIG. 1(E)).

In a preferred embodiment, as shown in FIG. 2(D), each of the multiple radial grooves 12 on the circular disk 10 is a curved radial groove 12a whose middle portion is curved in the direction of rotation of the circular disk 10.

In a more preferred embodiment, as shown in Figures 1(A) and 2(A), an intake amount adjustment valve 34 is provided at the other end 31 of the intake pipe 30. Preferably, a shaft 20 is provided that extends to the gas phase Pa along the central axis of the upper surface 10t of the circular disk 10, and a drive unit 25 is attached to the other end of the shaft 20. More preferably, as shown in Figures 2(A) and 2(F), a protective cover 40 is provided that covers the circular disk 10 and the shaft 20 and has a lower surface hole 43 facing the central groove 11 of the lower surface 10u of the circular disk and a discharge port 41 for discharging the discharge flow from the outer periphery of the circular disk, and is isolated from the rotation of the drive unit 25, and the intake pipe 30 is arranged along the outer surface of the protective cover 40.

The fine bubble generating device according to the present invention comprises a circular disk 10 having a lower surface 10u with a central groove 11 at the center and a plurality of radial grooves 12 extending from the central groove 11 to the periphery, the lower surface 10u of the circular disk 10 being covered with a doughnut-shaped cover plate 14 except for the central groove 11 , and then immersed in liquid phase Pb. One end 32 of an intake pipe 30, the other end 31 of which is connected to gas phase Pa, is brought into contact with the central groove 11 of the lower surface 10u of the circular disk 10, and the circular disk 10 is rotated around the central axis by a drive unit 25 to generate negative pressure in the central groove 11 of the lower surface 10u . This negative pressure causes the gas G sucked in from the one end 32 of the intake pipe 30 to mix with the liquid Q and flow into each of the radial grooves 12 covered with the doughnut-shaped cover plate 14 , and the bubbles S crushed in each of the radial grooves 12 are released from the periphery of the circular disk 10, thereby achieving the following effects.

(i) Since the drive device 25 that rotates the circular disk 10 and the intake pipe 30 that takes in gas G from the gas phase P are separated, one end 32 of the intake pipe 30 that takes in gas G can be fixed even when the circular disk 10 is rotated by the drive device 25.
(b) Therefore, even when the drive unit 25 is operating, the amount of gas G taken in can be finely adjusted by the intake amount adjustment valve 34 attached to one end 32 of the intake pipe 30, and the particle size and amount (concentration) of the fine bubbles S can be adjusted by continuously changing the amount of gas G taken in while observing the generation state of the fine bubbles S.

(c) In addition, it has become easy to connect supply ports for various gases (oxygen, ozone, nitrogen, etc.) to one end 32 of the intake pipe 30, and fine bubbles S containing such gases can be generated by the rotation of the circular disk 10. The particle size and amount (concentration) of the fine bubbles S containing such gases can also be adjusted by the intake amount adjustment valve 34.
(ii) Furthermore, the liquid Q and gas G are mixed in the central groove 11 of the circular disk 10 and then sucked into each radial groove 12. The bubbles S are crushed by cavitation in the flow path extending over the entire length of each radial groove 12. Therefore, the entire length of each radial groove 12 can be utilized for the micro-refining of the bubbles, and it is expected that the particle size of the micro-bubbles S released from the periphery of the disk 10 can be made finer and more uniform.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, modes and embodiments for carrying out the present invention will be described with reference to the accompanying drawings.
FIG. 1 is an explanatory diagram of one embodiment of a microbubble generating device according to the present invention. FIG. 11 is an explanatory diagram of another embodiment of the micro-bubble generating device according to the present invention. 1 is an explanatory diagram of the principle of fine bubble generation in the fine bubble generating device according to the present invention. FIG. FIG. 1 is an explanatory diagram of an example of a conventional microbubble generating device. FIG. 1 is an explanatory diagram of the principle of fine bubble generation in a conventional fine bubble generating device.

Figure 1 (A) shows an embodiment of the microbubble generator 1 of the present invention applied to target water areas such as aquaculture ponds and hydroponic cultivation fields. The generator 1 in the illustrated example comprises a circular disk 10 with grooves 11, 12 on the lower surface 10u, a drive unit 25 that rotates the circular disk 10 around its central axis, and an intake pipe 30 having one end 32 facing the lower surface 10u of the circular disk 10 and the other end 31 that communicates with the gas phase Pa.

As shown in FIG. 1(A), a circular disk 10 is immersed almost horizontally in the liquid phase Pb of the target water area, and the circular disk 10 is rotated around a vertical central axis at a required rotational speed ω by a drive unit 25, thereby crushing gas G sucked from the gas phase Pa through an intake pipe 30 to generate fine bubbles S. The present invention will be described below with reference to the illustrated example, but the application of the present invention is not limited to aquaculture ponds and hydroponic cultivation fields, and can be widely applied to the supply of fine bubbles S containing various gases G to a liquid Q.

Figure 1 (B) shows an enlarged cross-sectional view of the portion of the microbubble generator 1 in Figure 1 (A) including the circular disk 10 surrounded by the two-dot chain line B, and Figures 1 (C) and (D) show the upper surface 10t and the lower surface 10u of the circular disk 10 with a diameter R0. As shown in Figure 1 (D), the lower surface 10u of the circular disk 10 has a circular central groove 11 with a diameter R1 drilled in its center, and multiple radial grooves 12 are drilled from the central groove 11 to the periphery at a required angular interval θ. In the illustrated example, the multiple radial grooves 12 have the same angular interval θ, but the angular interval θ of each radial groove 12 may be different. Since the circular disk 10 is immersed in the liquid phase Pb of the target water area, it is desirable for the circular disk 10 to be made of a material (e.g., metal or synthetic resin) that is not easily corroded even when immersed in liquid phase Pb for a long period of time.

The illustrated microbubble generator 1 has a shaft 20 with one end fixed to the center of the upper surface 10t of the circular disk 10 and extending along the central axis, and a drive unit (e.g., a motor) 25 is attached to the other end of the shaft 20. As shown in FIG. 1(B), for example, one end of the shaft 20 is passed through the lower surface 10u of the circular disk 10, and the circular disk 10 is fixed to the shaft 20 by a retaining ring 21 provided on the lower surface 10u.

By including the shaft 20 as shown in the example in the figure in the fine bubble generator 1, when the circular disk 10 is immersed in liquid Pb, the other end of the shaft 20 is exposed above the liquid surface, and the drive unit 25 attached to the other end of the shaft 20 is prevented from contacting the liquid Pb, thereby preventing the temperature rise of the liquid Pb. However, the shaft 20 is not essential to the present invention, and if the temperature rise of the liquid P is not an issue, the shaft 20 may be omitted and the drive unit 25 may be attached integrally to the circular disk 10 immersed in the liquid Pb. The drive unit 25 may include a rotation speed adjustment means 26, and the particle size and amount of the fine bubbles S can be adjusted by the rotation speed ω of the circular disk 10. When used at sea or other places where it is difficult to connect to a power grid, the drive unit 25 may include a storage battery, a solar power generator, etc.

The illustrated example of the micro-bubble generator 1 also has a locking plate 22 supported by the gas phase Pa, and a drive unit 25 is installed on the locking plate 22. A shaft 20 is rotatably inserted through the locking plate 22, and the circular disk 10 is rotated around its central axis via the shaft 20 by the drive unit 25 on the locking plate 22, but the locking plate 22 can be left stationary. The locking plate 22 can be locked to a suitable member on the liquid surface, but if no suitable member exists, the locking plate 22 may be a floating plate that floats on the liquid surface. However, the locking plate 22 is not essential to the present invention and can be omitted.

The intake pipe 30 in the illustrated example has one end 32 submerged in the liquid phase Pb and facing the lower surface 10u of the circular disk 10, and the other end 31 supported by the locking plate 22 and connected to the gas phase Pa. The intake pipe 30 is also preferably made of a material that is not easily corroded in the liquid phase Pb (e.g., made of metal or synthetic resin), and can be, for example, a tube made of a relatively hard polyolefin resin. Since the inside of the intake pipe 30 becomes negative pressure when gas G is sucked in, if an excessively soft tube is used, the intake pipe 30 may be crushed in the inner diameter direction and become blocked when negative pressure is applied, so it is preferable to use a material that does not cause blockage even when negative pressure is applied. The other end 31 of the intake pipe 30 can be provided with an intake amount adjustment valve 34, and the particle size and amount of the fine bubbles S can be adjusted by the intake amount of the intake pipe 30.

Figure 1 (E) shows the principle of generating fine bubbles using the fine bubble generator 1. When the circular disk 10 is immersed horizontally in the liquid phase Pb of the target water area and rotated around its central axis by the drive unit 25, the centrifugal force F of the rotation causes liquid Q to flow from the central groove 11 of the circular disk 10 into each of the radial grooves 12, forming a liquid flow in each radial groove 12 that flows from the center to the periphery. This liquid flow generates negative pressure in the central groove 11 of the circular disk 10, and this negative pressure replenishes the central groove 11 with liquid Q from the liquid phase Pb, while gas G is sucked in from one end 32 of the intake pipe 30 and mixed with the liquid Q.

In FIG. 1(E), the liquid Q and gas G mixed in the central groove 11 of the circular disk 10 are crushed to a certain extent by cavitation in the central groove 11, and then flow from the central groove 11 into each radial groove 12 on the liquid flow formed by centrifugal force F. The liquid Q and gas G that flowed into each radial groove 12 are further crushed into small pieces by cavitation in the flow path over the entire length of each radial groove 12, and are released as fine bubbles S from the periphery of the disk 10. In other words, the fine bubble generator 1 in FIG. 1 can efficiently generate fine bubbles S using only the rotational drive energy of a relatively small disk, similar to the conventional fine bubble generator 50 described above with reference to FIGS. 4 and 5.

On the other hand, in the conventional fine bubble generator 50, the hollow rotating shaft pipe 70 was used not only as a flow path for taking in gas G into the disk 51 but also as the rotating shaft of the disk 51, so the position of the intake hole 71 of the pipe 70 changed according to the rotation of the disk 51. In contrast, the fine bubble generator 1 in FIG. 1 separates the drive unit 25 that rotates the circular disk 10 from the intake pipe 30 that takes in gas G from the gas phase P, so that the intake hole (one end of the intake pipe) 31 that takes in gas G can remain fixed even when the circular disk 10 is rotated by the drive unit 25, and an intake amount adjustment valve 34 is attached to the intake hole, and the intake amount of gas G can be changed steplessly by the intake amount adjustment valve 34 while observing the generation of fine bubbles S from the periphery of the disk 10.

In addition, the conventional micro-bubble generator 50 forms liquid flows from the center to the periphery in each of the hollow ducts 60 arranged radially around the central gap 63 when the disk 51 rotates. However, since the gas G is supplied to each of the hollow ducts 60 through the micro-through holes 56, rather than to the central gap 63, the flow path in which the gas G is crushed by cavitation is only a relatively short portion downstream of the micro-through holes 56 (see FIG. 5), and it has been experienced that the micro-bubbles S released from the edge of the disk contain ones with a relatively large diameter. In contrast, the micro-bubble generator 1 in FIG. 1 supplies gas G to the central groove 11 of the circular disk 10 to mix with the liquid Q, and the gas G is crushed by cavitation in a relatively long flow path that spans the entire length of each radial groove 12, so that the diameter of the released micro-bubbles S can be made finer and the diameter of the micro-bubbles S can be made uniform.

In the illustrated example, the circular disk 10 in the liquid phase Pb is placed almost horizontally, but the placement of the circular disk 10 does not necessarily have to be horizontal. As described above, if a liquid flow can be formed from the central groove 11 toward each radial groove 12 when the circular disk 10 rotates, fine bubbles S can be generated, so the circular disk 10 can be tilted as necessary, or placed nearly vertically.

Preferably, the radial grooves 12 on the lower surface 10u of the circular disk 10 are curved radial grooves 12a with the middle portion curved in the direction of rotation of the circular disk 10 as shown in FIG. 2(D) instead of the straight ones as shown in FIG. 1(D). FIG. 2(A) shows another embodiment of the microbubble generator 1 of the present invention. The microbubble generator 1 of FIG. 2 also includes a circular disk 10 with grooves 11, 12 on the lower surface 10u, a drive unit 25 that rotates the circular disk 10 around its central axis, and an intake pipe 30 having one end 32 facing the lower surface 10u of the circular disk 10 and the other end 31 that communicates with the gas phase Pa.

Figure 2 (B) shows an enlarged cross-sectional view of a portion of the microbubble generator 1 in Figure 2 (A) including the circular disk 10, and Figures 2 (C) and (D) show the upper surface 10t and the lower surface 10u of the circular disk 10. The lower surface 10u of the circular disk 10 shown in Figure 2 (D) has a circular central groove 11 with a diameter R1 drilled in its center, and multiple curved radial grooves 12a drilled at a required angular interval θ from the central groove 11 to the periphery. In the example shown in Figure 2, the multiple curved radial grooves 12a are also spaced at equal angular intervals θ, but the angular intervals θ of each curved radial groove 12a may be different.

The curved radial grooves 12a have an intermediate portion curved in the direction of rotation of the circular disk 10, and can extend the flow path from the central groove 11 to the periphery compared to the linear radial grooves 12 in FIG. 1(D). By crushing the gas G by cavitation throughout the entire long flow path, it is expected that the particle size of the fine bubbles S released from the periphery of the disk can be further refined and uniformed. The curved radial grooves 12a in the illustrated example are drilled to draw an arc, but the shape of the curved radial grooves 12a is not limited to the illustrated example. For example, the curved radial grooves 12a may be formed by drilling the intermediate portion of the linear radial grooves 12 as shown in FIG. 1(D) by bending it at a required angle once or more times in the opposite direction to the direction of rotation.

In addition, the linear radial grooves 12 in FIG. 1(D) disperse the fine bubbles S emitted from the periphery of the circular disk 10 over a wide 360-degree radial range, whereas the curved radial grooves 12a in FIG. 2(D) can emit the fine bubbles S in a direction along the periphery of the circular disk 10, preventing the emitted fine bubbles S from dispersing (see also FIG. 3(B)). For example, when installing the fine bubble generator 1 in a water tank, it may be necessary to concentrate the emission of the fine bubbles S in a direction where there is no wall of the water tank. By emitting the fine bubbles S in a direction along the periphery of the circular disk 10, the fine bubbles S can be easily guided in a specific direction using, for example, a protective cover 40 (see FIG. 2(F)) described later, and it becomes easy to focus the emission of the fine bubbles S in the required direction.

More preferably, as shown in FIG. 2(B), a donut-shaped cover plate 14 is provided to cover the portion of the lower surface 10u of the circular disk 10 other than the central groove 11. FIG. 2(E) shows a front view of the donut-shaped cover plate 14 as seen from below. By covering each curved radial groove 12a of the lower surface 10u with the donut-shaped cover plate 14, each curved radial groove 12a extending from the central groove 11 can be made into a cylindrical (culvert-like) pipe surrounded by the cover plate 14, and all the generated fine bubbles S can be released from the periphery of the circular disk 10, avoiding the waste of microbubbles S leaking into the liquid phase Pb from the middle of the flow path of each curved radial groove 12a. The reference numeral 15 in the figure indicates a screw that aligns and joins the circular disk 10 and the donut-shaped cover plate 14, but the circular disk 10 and the donut-shaped cover plate 14 may be joined by an adhesive or the like. In addition, even in the microbubble generator 1 of FIG. 1, it is effective to provide a donut-shaped cover plate 14 that covers the part of the lower surface 10u of the circular disk 10 other than the central groove 11.

The micro-bubble generator 1 in Fig. 2 also has a locking plate 22 supported by the gas phase Pa, a mounting base 27 for the drive unit 25 is provided on the locking plate 22, and the drive unit 25 is mounted on the mounting base 27. One end 32 of the intake pipe 30 is submerged in the liquid phase Pb and faces the lower surface 10u of the circular disk 10, and the other end 31 of the intake pipe 30 is supported by the locking plate 22 and is attached to the mounting base 27 for the drive unit 25. By connecting the intake pipe 30 and the mounting base 25 for the drive unit 25 in this way, the entire micro-bubble generator 1 including both can be made compact.

Figure 3 shows the principle of generating fine bubbles using the fine bubble generator 1 of Figure 2. As shown in Figure 3 (A), when the circular disk 10 is immersed horizontally in the liquid phase Pb of the target water area and rotated around the central axis by the drive unit 25, the centrifugal force F of the rotation causes liquid Q to flow from the central groove 11 of the circular disk 10 into each curved radial groove 12a covered with the doughnut-shaped cover plate 14, and a liquid flow is formed in each curved radial groove 12a flowing from the center to the periphery. This liquid flow generates negative pressure in the central groove 11 of the circular disk 10, and the liquid Q is replenished from the liquid phase Pb to the central groove 11 by this negative pressure, and gas G is sucked in from one end 32 of the intake pipe 30 and mixed with the liquid Q.

As shown in FIG. 3B, the liquid Q and gas G mixed in the central groove 11 of the circular disk 10 are crushed to a certain extent by cavitation in the central groove 11, and then flow from the central groove 11 into each curved radial groove 12a covered by a doughnut-shaped cover plate 14 on the liquid flow formed by centrifugal force F. The liquid Q and gas G that flowed into each curved radial groove 12a are further crushed into fine bubbles S by further cavitation in the flow path over the entire length of each radial groove 12, and all of the generated fine bubbles S are released as fine bubbles S from the periphery of the disk 10.

As shown in FIG. 3B, the curved radial grooves 12a release the micro-bubbles S in a direction along the periphery of the circular disk 10, so the released micro-bubbles S can flow along the periphery of the circular disk 10. Therefore, by providing a protective cover 40 that covers the outside of the circular disk 10, the micro-bubbles S can be guided and released in a specific direction from an outlet 41 provided in a part of the protective cover 40, and the micro-bubbles S can be released in a focused direction while preventing the micro-bubbles S from dissipating.

In this way, the objective of the present invention can be achieved by providing a "microbubble generating device that can fix the gas intake position when generating microbubbles."

In the embodiment shown in Figs. 1 and 2, one end 32 of the intake pipe 30 is connected to the gas phase Pa via the intake amount adjustment valve 34, but one end 32 of the intake pipe 30 can be connected to a supply port for various gases (oxygen, ozone, nitrogen, etc.), and based on the principle of generating fine bubbles S as shown in Fig. 3, fine bubbles S containing such gases can be generated and supplied by the rotation of the circular disk 10.

Figure 2 (F) shows an embodiment of a protective cover 40 that covers the circular disk 10 and the shaft 20. The protective cover 40 in the illustrated example is a combination of a cylindrical protective cover that covers the outside of the shaft 20 and a disk-shaped protective cover that covers the outside of the circular disk 10, and has a bottom hole 43 on the bottom surface 10u of the circular disk 10 facing the central groove 11, and a discharge port 41 that guides the discharge flow from the outer periphery of the circular disk 10 in a specific direction and discharges it.

As shown in FIG. 2(A), the upper end of the protective cover 40 in the illustrated example can be supported by the locking plate 22 and is isolated from the rotation of the drive unit 25. In other words, even when the drive unit 25 rotates the circular disk 10 around its central axis via the shaft 20, the locking plate 22 and the protective cover 40 can remain stationary.

Furthermore, the protective cover 40 in the illustrated example has a pair of insertion openings 42a, 42b through which the intake pipe 30 is inserted, and one end 32 of the intake pipe 30 supported on the locking plate 22 is inserted through the insertion openings 42a, 42b of the protective cover 40 and faces the underside 10u of the circular disk 10. By arranging the intake pipe 30 through the protective cover 40 in this manner, it becomes easier to arrange the intake pipe 30 along the outer surface of the protective cover 40, and it also becomes easier to position the one end 32 of the intake pipe 30 in an appropriate position facing the underside 10u of the circular disk 10, and the entire micro-bubble generator 1 including both the protective cover 40 and the intake pipe 30 can be made into a compact shape.

1...Microbubble generator
10...Circular disk 10t...Upper surface (of circular disk) 10u...Lower surface (of circular disk) 11...Central groove 12...Radial groove 12a...Curved radial groove 14...Donut-shaped cover plate 15...Screw 20...Shaft 21...Retaining ring (cap nut)
22... Locking plate (or floating plate)
25... Driving device 26... Driving speed adjustment means 27... Installation base 30... Intake pipe 31... Intake hole (at the other end of the intake pipe) 32... Exhaust hole (at one end of the intake pipe) 34... Intake amount adjustment valve 40... Protective cover 41... Bubble discharge ports 42a, 42b... Pipe insertion port 50... Fine bubble generating device
51...Disk 52...Substrate 53...Substrate 54...Peripheral seal material 55...Airtight chamber 56...Micro through hole 60...Hollow duct (hollow pipe) 60a...Drain outlet 61...Doughnut plate 62...Central hole (of doughnut plate) 63...Central gap 70...Hollow rotating shaft pipe 71...Intake hole 72...Intake amount adjustment plug 73...Exhaust hole 76, 77...Annular pressing material (pressing boss)
80: Drive device 81: Drive shaft 82: Coupling 83: Rotational speed adjustment means Pa: Gas phase Pb: Liquid phase S: Fine bubbles L: Length of hollow pipe G: Gas Q: Liquid R0: Disk diameter R1: Central groove diameter (diameter of central hole 62)
θ…Mutual angular spacing ω…Rotation speed

Claims (6)

A fine bubble generator comprising: a circular disk having a central groove in the center and a plurality of radial grooves extending from the central groove to the periphery on its underside and immersed in a liquid phase; a donut-shaped cover plate covering the entire underside of the circular disk except for the central groove; a drive unit for rotating the circular disk around its central axis; and an intake pipe having one end facing the central groove on the underside of the circular disk and the other end communicating with the gas phase, wherein negative pressure is generated in the central groove by the rotation of the circular disk by the drive unit, and the gas sucked in from one end of the intake pipe is mixed with the liquid by the negative pressure and flows into each of the radial grooves covered by the donut-shaped cover plate , and the air bubbles crushed in each radial groove are released from the periphery of the circular disk. A microbubble generating device according to claim 1, in which each of the multiple radial grooves on the circular disk is a curved radial groove whose middle portion is curved in the direction of rotation of the circular disk. 3. The fine bubble generating device according to claim 1 , further comprising an intake amount adjusting valve provided at the other end of said intake pipe. 4. The fine bubble generating device according to claim 1 , further comprising a shaft extending along the central axis of the upper surface of the circular disk to the gas phase, and the driving device attached to the other end of the shaft. 5. A micro-bubble generating device according to claim 4 , further comprising a protective cover which covers the circular disk and shaft, has a bottom hole facing a central groove on the bottom surface of the circular disk, and has an outlet port for discharging the discharge flow from the outer periphery of the circular disk, and is isolated from the rotation of the drive unit, and an intake pipe is arranged along the outer surface of the protective cover. 6. The fine bubble generating device according to claim 1 , further comprising a gas generating device for generating oxygen, ozone, nitrogen or other gas, connected to the other end of said intake pipe.