Microbubble generating 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, focusing on their physical properties, mechanisms of generation, specific uses, and 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-sized microbubbles, and the improvement of water quality by supplying water containing microbubbles to rice paddies.

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

[0004] Patent Document 2 discloses a microbubble generating plate having a bubble generating section that generates microbubbles from the surface in a liquid, and is formed by providing one or more convex portions in a row on the surface, and the convex portions each comprise an apex portion that forms the peak, a base portion that forms the starting point of the convex portion, and a sloped portion connecting the apex and the base portion, with the distance between any one point on the base portion and an opposing point across the apex from the any one point being 0.1 to 1 mm, and the angle between the two opposing sloped portions being 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 Patent Document 1, recesses are provided to form valleys, but the distance between the two bases facing each other across the bottom apex is set to 0.1 to 1 mm, and the distance between the bases is inappropriate, so that, for example, vortices created by the water flow supplied to the microbubble generating plate cannot be efficiently generated, and a large number of microbubbles cannot be generated.In addition, the microbubbles generated are large and are at the micro level.

[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 with the 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 it is not possible to generate many microbubbles.

[0008] Therefore, the present invention provides a fine-bubble generating plate that can efficiently generate vortices 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 problem is solved by Different sizes, shapes and heightsA fine bubble generating plate having a fine bubble generating surface on which a plurality of convex portions are formed to generate fine bubbles, wherein the relationship between adjacent first and second convex portions is such that a convex top of the first convex portion and a position where a slope from the convex top of the first convex portion to the convex top of the second convex portion changes to an upward slope are defined as a convex bottom of the first convex portion, a distance W1 between the convex top of the first convex portion and a first intermediate position of a straight line connecting the convex top and convex bottom of the first convex portion, a distance W2 between the convex top of the second convex portion and a second intermediate position of a straight line connecting the convex top and convex bottom of the second convex portion, and a distance D between the first and second intermediate positions, satisfying the relationship D≧W1+W2. The distance D is 0.5 to 100 μm. This can be achieved by providing a fine bubble generating plate with a plurality of protrusions.

[0010] The microbubble generating surface is, for example, a peripheral surface. The interval D is, for example, 0.5 to 100 μm, and the size of the microbubbles generated by the microbubble generating surface is, for example, 10 to 200 nm. The microbubble generating surface is, for example, movable or rotatable. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a diagram illustrating the fine bubble generating plate of the present embodiment. [Figure 2] FIG. 2 is a diagram showing in detail the cross-sectional configuration of the convex portions formed on the surface of the fine bubble generating plate, and is an enlarged view of a part of the fine bubble generating plate. [Figure 3] 1 is a diagram illustrating the process of generating vortex currents on the surface of a fine bubble generating plate. FIG. [Figure 4] 10A and 10B are diagrams illustrating an example of a water flow flowing over a convex portion having a relatively gentle apex. [Figure 5] 10A and 10B are diagrams illustrating an example of a water flow flowing through a convex portion having a depression at the top of the convex portion. [Figure 6]FIG. 2 is a diagram showing the fine bubble generating surface as viewed from above, with a portion of the fine bubble generating surface enlarged. [Figure 7] FIG. 1 is a diagram showing an example of a micro-bubble generating device in which the micro-bubble generating plate of this embodiment is attached to a cylindrical member. [Figure 8] FIG. 10 is a diagram showing the fine bubble generating surface of this embodiment formed on the vanes of a pump. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. 1 is a diagram illustrating the fine bubble generating plate of this 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 a method such as blasting abrasives of optimal size onto the surface 2, or by a processing method such as wire electric discharge machining or etching.

[0014] Furthermore, when a liquid such as pressurized water 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, and fine bubbles are generated.

[0015] 2 is a diagram illustrating the configuration of, for example, two adjacent protrusions among the many protrusions formed on the fine-bubble generating surface 2. In the figure, an example of two adjacent protrusions, for example, protrusions 3-1 and 3-2, is illustrated. The figure shows an enlarged portion of the fine-bubble generating plate 1, illustrating the cross-sectional configuration of, for example, two adjacent protrusions 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 example vary in size, shape and height, but are formed under the following conditions.

[0018] That is, as shown in Figure 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 so as to satisfy the relationship D≧W1+W2, where W1 is the distance between the first intermediate position L1' of the 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 the second intermediate position L2' of the 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 Figure 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 intermediate position 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 intermediate position 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 intermediate position of the straight line L2 formed by connecting this convex apex 3-2a and convex bottom 3-2b is L2', and the horizontal distance between this intermediate position 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 convex portions 3 are formed on the surface (fine bubble generating surface 2) of the fine bubble generating plate 1 in this example so that the relationship D≧W1+W2 is satisfied.

[0021] This configuration allows a large number of vortex currents to 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 vortex currents in the recessed portions, 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 of the convex portion 3-1, reaches the convex top 3-1a, and then 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), where it forms a vortex 5.

[0023] The size of this vortex 5 corresponds to the shape of the recess 4 and the height of the next protrusion 3-2; for example, a vortex 5 having a size corresponding to the diameter of the recess 4 is generated. This is also true for the other protrusions 3 (protrusions 3-3, 3-4, ...) not shown, 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 example, 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 recessed portion 4, and this D is formed so that the relationship D≧W1+W2 is satisfied, thereby ensuring that vortex flows 5 are 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, we found that when D, which is the condition for the convex portions 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 will be 10 to 200 nm, which is the optimum size 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 convex portions 3 of different sizes, shapes, and heights as described above, and some of the convex portions 3 have relatively gentle apexes 3a, as shown in Figure 4. In this case, when the water flow that rises along the side of the convex portion 3 reaches the convex portion 3a and then flows down into the concave portion 4, negative pressure is generated at the convex portion 3a, and a vortex 6 is generated at the convex portion 3a as shown in the figure.

[0027] Like the vortex 5 described above, the vortex 6 generated in this way is also a fine bubble generated on the fine bubble generating plate 1 (fine bubble generating surface 2) of this embodiment, and contributes to the generation of even more fine bubbles. Furthermore, if there is a depression 3a' on the convex top 3a as shown in Figure 5, a large negative pressure is generated on the convex top 3a, generating the vortex 6. This vortex 6 is also a fine bubble generated on the fine bubble generating plate 1 (fine bubble generating surface 2) of this embodiment, and contributes 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 view of the fine bubble generating surface 2, for example, as seen from above, showing 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 portions 3 (3a, 3b, 3c, ...) of different shapes and sizes as described above, and adjacent convex portions 3 are formed so as to satisfy 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 in this manner, the water flow collides with the convex parts 3 formed on the fine-bubble generating surface 2, flows along both sides of the convex parts 3, and generates vortex currents 7 behind.

[0031] For example, in the same figure, if the intermediate position of the straight line L1 formed by connecting the highest and lowest positions of the convex portion 3a is L1' and the intermediate position of the straight line L2 formed by connecting the highest and lowest positions 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 along both sides of the convex portion 3a, and generates a vortex flow 7a behind it as shown in the figure. 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 so that they 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] This also 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-described 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 these three fine bubble generating plates 1a to 1c is a fine bubble generating plate having a fine bubble generating surface 2 on the surface of which numerous protrusions 3 as described in Fig. 1 above are formed.

[0035] Furthermore, with respect to the fine bubble generating plates 1a to 1c attached to the cylindrical member 8, a large number of convex portions 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, as described above, a large number of protrusions 3 are formed on both sides of each of the three fine-bubble generating plates 1a to 1c, and a large amount of nano-level fine bubbles are generated from each fine-bubble generating surface 2. 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 example is attached to the cylindrical member 8, but the fine bubble generating plate 1 may be attached to any member other than the cylindrical member 8, such as a square, hexagonal, or octagonal member. 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, instead of a square member or a pipe.

[0039] In addition to the pump impellers, the fine bubble generating surface 2 of this example, which has many convex portions formed thereon, may also be provided on the impeller casing, the mixer part of a concrete mixer truck or the like, a water wheel, a moving part of a screw pulsator, etc.

[0040] 8 is a diagram showing the fine bubble generating surfaces of this embodiment formed on the vanes of a pump. In the figure, many protrusions are formed on both sides of the four vanes 9a to 9d of the pump 9, forming the fine bubble generating surfaces 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 blade 9a of pump 9, and 10d in the figure is an enlarged view showing the state of the fine bubble generating surface on the surface of blade 9d of pump 9. Of course, similar fine bubble generating surfaces are formed on both sides of blades 9b and 9c of 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 parts that come into contact with the liquid, such as passages within the pump through which the liquid flows. Furthermore, 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 also be formed on the surface of a muddler used to mix alcoholic beverages, etc. The fine bubble generating plate 3 of this embodiment may also be flexibly deformed so that water flows efficiently along the fine bubble generating surface 3 on which many protrusions are formed.

[0044] In the above description, an accelerated water flow is supplied to the fine bubble generating plate 1, but the supplied water flow may also be a swirling flow. Furthermore, 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 stream 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 to 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 impellers 10a, 10c··Enlarged view of a portion of Figure 5

Claims

1. A fine bubble generating plate having a fine bubble generating surface that generates fine bubbles and has a plurality of convex portions of different sizes, shapes, and heights formed on the surface, The relationship between the first and second adjacent protrusions is as follows: a convex apex of the first convex portion and a position where a downward slope from the convex apex of the first convex portion toward the convex apex of the second convex portion changes to an upward slope are defined as a convex bottom of the first convex portion, and W1 is a distance between a first intermediate position of a straight line formed by connecting the convex apex and the convex bottom of the first convex portion and the convex apex of the first convex portion, a convex apex of the second convex portion and a position where a slope that descends from the convex apex of the second convex portion toward the convex apex of the first convex portion changes to a slope that ascends are defined as a convex bottom of the second convex portion, and a distance W2 is defined between a second intermediate position of a line formed by connecting the convex apex and the convex bottom of the second convex portion and the convex apex of the second convex portion, A fine bubble generating plate having a plurality of convex portions, the convex portions having a relationship of D≧W1+W2, where D is a distance between the first and second intermediate positions, and the distance D is 0.5 to 100 μm.

2. 2. The 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 size of the fine bubbles generated by the fine bubble generating surface is 10 to 200 nm.

4. 3. The fine bubble generating plate according to claim 1, wherein the fine bubble generating surface is movable or rotatable.

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