Fine bubble generation plate

Abstract

To provide a fine bubble generation plate generating nano level fine bubbles.SOLUTION: There is provided a fine bubble generation plate comprising a fine bubble generation surface on which multiple salients are formed. In the multiple salients, cross sections of adjacent first and second salients have a relationship of: D≥W1+W2, when an interval between a first intermediate position of a straight line formed by connecting a salient apex and a salient bottom of the first salient, and the salient apex, is W1, an interval between a second intermediate position of a straight line formed by connecting a salient apex and a salient bottom of the second salient, and the salient apex, is W2, and an interval between the first and second intermediate positions is D.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a fine bubble generating plate that generates fine bubbles at the nano level. [Background technology]

[0002] Today, research into nano-level microbubbles is rapidly progressing with regard to their physical properties, the mechanism of their generation, specific uses, and their practical applications. For example, research is being conducted into the purification and sterilization of polluted water, the cultivation of aquatic organisms using water containing nano-order microbubbles, and the improvement of water quality by supplying water containing microbubbles to rice paddies.

[0003] Many methods have been proposed for generating such microbubbles. For example, Patent Document 1 discloses a microbubble generating plate having a bubble generating surface that generates microbubbles from the surface in liquid. This invention relates to a microbubble generating plate having a plurality of valleys formed by providing depressions in the plane of the plate, the valleys being composed of a bottom apex forming the apex of the depression, a base apex forming the starting point of the depression, and a valley surface connecting the bottom apex and the base apex, the distance between the two base apex portions facing each other across the bottom apex portion is set to 0.1 to 1 mm, and the angle between the two opposing valley surface portions is set to 10 to 90°.

[0004] Patent Document 2 discloses a microbubble generating plate having a bubble generating section which generates microbubbles from the surface in a liquid, the microbubble generating plate being formed by providing one or more convex portions in a row on the surface, the convex portions each consisting of an apex portion forming an apex, a base portion forming the starting point of the convex portion, and a slope portion connecting the apex portion and the base portion, the distance between any one point on the base portion and an opposing point opposite the any one point across the apex portion is 0.1 to 1 mm, and the angle between the two opposing slope portions is 15 to 75°. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2015-166055 A [Patent Document 2] JP 2017-170285 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the microbubble generating plate described in the above Patent Document 1, a valley is formed by providing a depression, but the distance between the two base apexes facing each other across the bottom apex is set to 0.1 to 1 mm, and the distance between the base apexes is inappropriate, so that, for example, a vortex created by the water flow supplied to the microbubble generating plate cannot be efficiently generated, and many microbubbles cannot be generated. In addition, the size of the generated microbubbles is large, and they are micro-level microbubbles.

[0007] Furthermore, the microbubble generating plate described in Patent Document 2 is an invention in which convex portions are provided on a substrate, but the distance between opposing points across the apex of the convex portion is 0.1 to 1 mm, and as mentioned above, the distance between the apexes is inappropriate, and the water flow supplied to the microbubble generating plate cannot efficiently generate vortexes created by collision with the convex portions, and therefore many microbubbles cannot be generated.

[0008] Therefore, the present invention provides a fine-bubble generating plate that can efficiently generate vortexes created by a liquid flow (e.g., a water flow) supplied to the fine-bubble generating plate, and can efficiently generate a large amount of fine bubbles. [Means for solving the problem]

[0009] According to the present invention, the above object can be achieved by providing a fine-bubble generating plate having a fine-bubble generating surface on whose surface a plurality of convex portions are formed, in which the cross-sectional shapes of adjacent first and second convex portions satisfy the relationship D≧W1+W2, where W1 is the distance between the convex portion and a first intermediate position of a line connecting the convex apex and the convex bottom of the first convex portion, W2 is the distance between the convex apex and a second intermediate position of a line connecting the convex apex and the convex bottom of the second convex portion, and D is the distance between the first and second intermediate positions.

[0010] The fine bubble generating surface is, for example, a peripheral surface. The interval D is, for example, 0.5 to 100 μm, and the size of the fine bubbles generated by the fine bubble generating surface is, for example, 10 to 200 nm. The fine bubble generating surface is, for example, movable or rotating. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is a diagram illustrating a fine bubble generating plate according to the present embodiment. [Diagram 2] FIG. 2 is a diagram showing in detail the cross-sectional configuration of protrusions formed on the surface of a fine bubble generating plate, and is an enlarged view of a portion of the fine bubble generating plate. [Diagram 3] 1 is a diagram illustrating the process by which vortex currents are generated on the surface of a fine bubble generating plate. FIG. [Figure 4] 1A and 1B are diagrams illustrating an example of a water flow flowing over a convex portion having a relatively gentle top shape. [Diagram 5] 13A and 13B are diagrams illustrating an example of a water flow flowing through a convex portion having a depression at its top. [Figure 6] FIG. 2 is a top view of the fine bubble generating surface, showing an enlarged portion of the fine bubble generating surface. [Figure 7] FIG. 1 is a diagram showing an example of a fine-bubble generating device in which the fine-bubble generating plate of this embodiment is attached to a cylindrical member. [Figure 8] 1 is a diagram showing a pump impeller having a fine bubble generating surface according to the present embodiment formed thereon. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. 1 is a diagram illustrating a fine bubble generating plate according to the present embodiment. The fine bubble generating plate 1 of this embodiment has a predetermined thickness and is made of a material such as a metal such as stainless steel, iron, or copper, or a plate-shaped resin or silicon.

[0013] A large number of protrusions 3 are formed on the surface (fine bubble generating surface) 2 of this fine bubble generating plate 1. The protrusions 3 are formed by, for example, a method of spraying an abrasive of an optimal size onto the surface 2 by blasting, wire electric discharge machining, etching, or other machining methods.

[0014] When a liquid such as a pressurized water flow is supplied to the fine-bubble generating plate 1, a vortex is generated by the convex portions 3 formed on the fine-bubble generating surface 2, generating fine bubbles.

[0015] 2 is a diagram for explaining the configuration of, for example, two adjacent convex portions among the many convex portions formed on the fine bubble generating surface 2. In the figure, an example of two adjacent convex portions, for example, convex portion 3-1 and convex portion 3-2, is explained. The figure shows an enlarged portion of the fine bubble generating plate 1, and for example, shows the cross-sectional configuration of two adjacent convex portions, 3-1 and 3-2.

[0016] A large number of protrusions 3 of different sizes, shapes and heights are formed on the fine bubble generating plate 1 (fine bubble generating surface 2), and the adjacent protrusions 3-1 and 3-2 also have different sizes, shapes and heights.

[0017] As described above, the convex portions 3 formed on the fine bubble generating surface 2 of this embodiment differ in size, shape and height, but are formed under the following conditions.

[0018] That is, as shown in FIG. 2, if one of the adjacent convex portions 3, convex portion 3-1, is designated as the first convex portion, and the other convex portion 3-2 is designated as the second convex portion, the cross-sectional shapes of the adjacent first and second convex portions are formed to have a relationship of D≧W1+W2, where W1 is the distance between a first intermediate position L1' of a straight line L1 formed by connecting the convex apex 3-1a and the convex bottom 3-1b of the first convex portion (convex portion 3-1) and the convex apex 3-1a, W2 is the distance between a second intermediate position L2' of a straight line L2 formed by connecting the convex apex 3-2a and the convex bottom 3-2b of the second convex portion (convex portion 3-2) and the convex apex 3-2a, and D is the distance between the first intermediate position L1' and the second intermediate position L2'.

[0019] Specifically, as shown in FIG. 2, the highest point of the convex portion 3-1 is the convex apex 3-1a, the lowest point of the convex portion 3-1 is the convex bottom 3-1b, the midpoint of the straight line L1 formed by connecting the convex apex 3-1a and the convex bottom 3-1b is L1', and the horizontal distance between this midpoint L1' and the convex apex 3-1a is W1.

[0020] Similarly, for convex portion 3-2, the highest point of convex portion 3-2 is convex apex 3-2a, the lowest point of convex portion 3-2 is convex bottom 3-2b, the midpoint of straight line L2 formed by connecting convex apex 3-2a and convex bottom 3-2b is L2', and the horizontal distance between this midpoint L2' and the convex apex 3-2a is W2. When the distance between the intermediate positions L1' and L2' is D, a large number of protrusions 3 are formed on the surface (fine bubble generating surface 2) of the fine bubble generating plate 1 in this embodiment so as to satisfy the relationship D≧W1+W2.

[0021] With this configuration, a large number of vortex currents can be generated on the fine-bubble generating surface 2. That is, the water flowing on the fine-bubble generating plate 1 passes over the convex apex 3-1a of the first convex portion 3-1, forms a vortex in the concave portion, and generates fine bubbles.

[0022] This state is explained in Fig. 3. When an accelerated water flow is supplied to the fine bubble generating plate 1 from the direction shown in Fig. 1, the accelerated water flow collides with the convex portion 3-1 as shown in Fig. 3, and the water flows along the side surface of the convex portion 3-1, reaches the convex top portion 3-1a, and further flows into the concave portion 4 formed between the first convex portion (convex portion 3-1) and the second convex portion (convex portion 3-2), and forms a vortex flow 5 in this concave portion 4.

[0023] The size of this vortex 5 corresponds to the shape of the recess 4 and the height of the next protrusion 3-2, and for example, a vortex 5 having a size corresponding to the diameter of the recess 4 is generated. This is the same for the other protrusions 3 (not shown) (protrusions 3-3, 3-4, ...), and a vortex 5 having a size corresponding to the recess 4 formed between each of the protrusions 3 is generated.

[0024] As described above, in the fine-bubble generating plate 1 of this embodiment, a large number of convex portions 3 are formed on the surface (fine-bubble generating surface 2) of the fine-bubble generating plate 1 so that the relationship D≧W1+W2 is satisfied, and the distance D between the first intermediate position L1' and the second intermediate position L2' corresponds to the size of the above-mentioned recessed portion 4, and this D is formed so that the relationship D≧W1+W2 is satisfied, so that vortex flows 5 can be reliably generated in all recessed portions 4 formed on the fine-bubble generating surface 2, thereby generating a large amount of fine bubbles.

[0025] In our various experiments, it was found that when D, which is the condition for the convex portion 3 formed on the fine bubble generating plate 1, is set to, for example, 0.5 to 100 μm, the size of the fine bubbles generated by the fine bubble generating surface 3 is 10 to 200 nm, which is optimal for generating nano-level fine bubbles.

[0026] On the other hand, the fine-bubble generating plate 1 (fine-bubble generating surface 2) of this embodiment has many projections 3 of different sizes, shapes and heights formed thereon as described above, and some projections 3 have relatively gentle apexes 3a as shown in Fig. 4. In this case, when the water flow that rises along the side of the projection 3 reaches the apex 3a and then flows down into the recess 4, negative pressure is generated at the apex 3a, and a vortex 6 is generated at the apex 3a as shown in the figure.

[0027] The vortex currents 6 thus generated are also fine bubbles generated on the fine bubble generating plate 1 (fine bubble generating surface 2) of this embodiment, similar to the above-mentioned vortex currents 5, and contribute to the generation of even more fine bubbles. Furthermore, if there is a depression 3a' on the convex apex 3a as shown in Fig. 5, a large negative pressure is further generated on the convex apex 3a, generating the vortex currents 6. These vortex currents 6 are also fine bubbles generated on the fine bubble generating plate 1 (fine bubble generating surface 2) of this embodiment, and contribute to the generation of even more fine bubbles.

[0028] Next, in the fine bubble generating plate 1 of this embodiment, a vortex flow is also generated in a direction horizontal to the fine bubble generating surface 2 in addition to the vortex flows 5 and 6 in the cross-sectional direction.

[0029] 6 is a diagram of the fine bubble generating surface 2 as seen, for example, from above, and shows an enlarged portion of the fine bubble generating surface 2. As shown in the figure, the fine bubble generating plate 1 (fine bubble generating surface 2) is formed with a large number of convex parts 3 (3a, 3b, 3c, ...) of different shapes and sizes as described above, and adjacent convex parts 3 are formed so as to have the relationship D≧W1+W2 as described above.

[0030] By supplying an accelerated water flow from the direction shown in Figure 1 to the fine-bubble generating plate 1 of this example configured as described above, the water flow collides with the convex portion 3 formed on the fine-bubble generating surface 2, flows along both sides of the convex portion 3, and generates a vortex flow 7 behind it.

[0031] For example, in the same figure, if the intermediate position of the straight line L1 formed by connecting the highest point and the lowest point of the convex portion 3a is L1', and the intermediate position of the straight line L2 formed by connecting the highest point and the lowest point of the adjacent convex portion 3b is L2', the distance between them is set to D, and the distance W1 between the apex of the convex portion 3a and the intermediate position L1' and the distance W2 between the apex of the convex portion 3b and the intermediate position L2' are formed to have the relationship D≧W1+W2 as described above.

[0032] With this configuration, for example, a water current flowing over the fine-bubble generating plate 1 hits the convex portion 3a, flows over both sides of the convex portion 3a as shown in the figure, and generates a vortex flow 7a behind it. This vortex flow 7a can be generated without being influenced by the adjacent convex portion 3b because the distance between the adjacent convex portions 3b is set to D as described above. In other words, the adjacent convex portions 3a and 3b are formed to have the relationship D≧W1+W2 as described above, and the vortex flow 7a can be generated on the fine-bubble generating surface 2 without being influenced by the downstream convex portion 3b.

[0033] The same applies to the other protrusions 3b, 3c, . . . , and vortex flows 7b, 7c, 7d, . . . are generated behind the protrusions 3b, 3c, .

[0034] Fig. 7 shows an example of a fine bubble generating device in which the fine bubble generating plate 1 having the above-mentioned configuration is attached to a cylindrical member 8. As shown in the figure, three fine bubble generating plates 1a to 1c are arranged inside the cylindrical member 8, for example, radially in cross section. Each of the three fine bubble generating plates 1a to 1c is a fine bubble generating plate having a fine bubble generating surface 2 on whose surface a large number of protrusions 3 as described in Fig. 1 above are formed.

[0035] Moreover, with respect to the fine bubble generating plates 1a to 1c attached to the cylindrical member 8, a large number of protrusions 3 are formed on both sides of each of the fine bubble generating plates 1a to 1c.

[0036] As shown in the figure, when an accelerated water flow is supplied from the left side of this fine-bubble generator and a high-speed water flow is supplied to the fine-bubble generating plates 1a to 1c attached inside, a large amount of nano-level fine bubbles are generated from each fine-bubble generating surface 2 because a large number of protrusions 3 are formed on both sides of each of the three fine-bubble generating plates 1a to 1c as described above. The fine bubbles generated in this way are discharged from the fine-bubble generator and used for the desired purpose.

[0037] In the above description, the fine bubble generating plate 1 of this embodiment is attached to the cylindrical member 8, but the fine bubble generating plate 1 may be attached to a rectangular, hexagonal, octagonal, or other angular member, without being limited to the cylindrical member 8. Also, instead of attaching the fine bubble generating plate 1 to the cylindrical member 8, a protrusion 3 having the same structure as the fine bubble generating plate 1 may be provided on the inner peripheral surface of the cylindrical member 8.

[0038] Furthermore, the fine bubble generating device may be one in which the fine bubble generating surface 2 is provided on a member having a concave, layered or honeycomb shape, rather than on a square member or a pipe.

[0039] In addition to the pump impellers, the fine bubble generating surface 2 of this embodiment having a large number of protrusions may be provided on the impeller casing, the mixer part of a concrete mixer truck, a water wheel, a screw pulsator, or other moving parts.

[0040] Fig. 8 is a diagram showing the fine bubble generating surface of this embodiment formed on the vanes of a pump. In this figure, a large number of protrusions are formed on both sides of the vanes 9a to 9d of the four pumps 9, forming the fine bubble generating surface of this embodiment.

[0041] For example, 10a in the figure is an enlarged view showing the state of the fine bubble generating surface on the surface of the blade 9a of the pump 9, and 10d in the figure is an enlarged view showing the state of the fine bubble generating surface on the surface of the blade 9d of the pump 9. Of course, similar fine bubble generating surfaces are formed on both sides of the blades 9b and 9c of the pump 9.

[0042] In the above explanation, the fine bubble generating surface 2 is formed on the pump blades. However, the fine bubble generating surface 2 of this example may be formed not only on the pump blades but also on any part that comes into contact with the liquid, such as a passage within the pump through which the liquid flows. Moreover, it goes without saying that the pump in which the fine bubble generating surface 2 of this embodiment is formed can be applied to various pumps such as vortex pumps and turbine pumps.

[0043] The fine bubble generating surface 2 of this embodiment may be formed on the surface of a stirrer for mixing alcoholic beverages, etc. The fine bubble generating plate 3 of this embodiment may be flexibly deformed so that water flows efficiently along the fine bubble generating surface 3 on which a large number of protrusions are formed.

[0044] In the above description, an accelerated water flow is supplied to the fine bubble generating plate 1, but the water flow may be a swirling flow. Also, the water flow is not limited to a water flow, and may be a swirling flow of alcohols such as methanol, ethanol, and propanol, organic solvents such as acetone, hexane, and toluene, or mineral oils such as petroleum.

[0045] In the explanation of FIG. 1 above, a liquid such as a pressurized water flow is supplied to the fine-bubble generating plate 1. However, the liquid supplied to the fine-bubble generating plate 1 may be a gas or liquid containing a gas such as air, hydrogen, deuterium, oxygen, ozone, nitrogen, carbon dioxide, chlorine, nitrogen dioxide, hydrogen sulfide, helium, argon, or neon.

[0046] 1, 1a~1c: Micro-bubble generating plate 2. Microbubble generating surface 3, 3-1, 3-2... Convex part 3-1a, 3-2a... Convex top 3-1a, 3-2b... Convex bottom 4. Recess 5,6,7...vortex 8. Cylindrical member 9. Pump 9a~9d Pump impeller 10a, 10c: Enlarged views of a portion of Fig. 5

Claims

1. A fine bubble generating plate having a fine bubble generating surface for generating fine bubbles, the fine bubble generating surface having a plurality of convex portions formed on the surface, The cross-sectional shapes of the adjacent first and second protrusions are a first intermediate position of a line connecting the convex apex and the convex bottom of the first convex portion and a distance between the first intermediate position and the convex apex of the first convex portion; a second intermediate position of a line connecting the convex apex and the convex bottom of the second convex portion and a distance between the second intermediate position and the convex apex of the second convex portion and a distance between the first intermediate position and the second intermediate position is W2; and

2. 2. A fine bubble generating plate according to claim 1, wherein the fine bubble generating surface is a peripheral surface.

3. 3. The fine bubble generating plate according to claim 1, wherein the distance D is 0.5 to 100 μm.

4. 3. The fine bubble generating plate according to claim 1, wherein the size of the fine bubbles generated by the fine bubble generating surface is 10 to 200 nm.

5. 3. The fine bubble generating plate according to claim 1, wherein the fine bubble generating surface moves or rotates.

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