Microbubble generator and method

Abstract

This invention provides a microbubble generator and method, comprising a first section, a second section, and a third section. The first section is a Venturi tube structure with an ultrafiltration membrane at the air inlet for pre-shearing and pre-mixing of bubbles. The second section is a reverse Tesla valve principle flow channel, including at least two converging channels for further bubble shearing. The third section is a uniform mixing channel, connected to all flow paths of the second section and converging into a single channel for uniform dispersion of microbubbles, forming a microbubble fluid. This invention solves the problems of complex structure, uneven bubble size, and insufficient gas-liquid mixing in existing microbubble generators, offering advantages such as simple structure and the ability to produce uniformly sized and mixed gas-liquid particles.

Description

Technical Field

[0001] This invention belongs to the field of microbubble generator technology, specifically relating to a microbubble generator and method. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Microbubbles are ultra-small bubbles formed from gas in a liquid, typically ranging in diameter from a few micrometers to hundreds of micrometers. Microbubble technology utilizes the enormous surface area to volume ratio of these tiny bubbles to greatly enhance mass and heat transfer between gas and liquid, thereby altering various properties of the liquid. This brings many new application opportunities for industrial production and environmental remediation.

[0004] Currently, based on the different principles by which microbubble generators produce bubbles, they can be categorized into mechanical, hydrodynamic, and acoustic types. The mechanical type is the most common, using a high-speed rotating rotor to shear gas into tiny bubbles. Its advantages include simple structure and high efficiency, but it suffers from problems such as difficulty in controlling bubble size and a tendency for aggregation. The hydrodynamic type utilizes the shear pulsation and eddies of fluids to generate bubbles. For example, it can use the shear interface between two fluids with different flow rates to generate microbubbles. This method offers good controllability, but the equipment is complex and its efficiency is generally low. The acoustic type uses the oscillation of high-frequency sound waves to continuously shear and refine the bubbles. It produces well-dispersed bubbles, but the equipment cost is high.

[0005] In summary, existing microbubble generators often suffer from problems such as low bubble generation efficiency and inaccurate particle size control. Summary of the Invention

[0006] To address the aforementioned problems, this invention proposes a microbubble generator and method. This invention solves the problems of complex structure, uneven bubble size, and insufficient gas-liquid mixing in existing microbubble generators, and has the advantages of simple structure and the ability to produce uniformly sized and homogeneously mixed gas and liquid particles.

[0007] According to some embodiments, the present invention adopts the following technical solution:

[0008] A microbubble generator includes a first section, a second section and a third section, wherein the first section is a venturi tube structure and an ultrafiltration membrane is provided at the air inlet for pre-shearing and pre-mixing of bubbles.

[0009] The second section is a reverse Tesla valve principle flow channel, which includes at least two flow channels with confluence points for further shearing of bubbles;

[0010] The third section is a uniform mixing channel, which is connected to all the flow paths of the second section and converges into one channel for uniform dispersion of microbubbles to form microbubble fluid.

[0011] As an alternative implementation, the first segment includes an inlet, a contraction segment, a narrowing segment, a divergence segment, and a premixing segment arranged sequentially. The diameter of the narrowing segment is smaller than the diameter of the inlet and is smoothly transitioned by the contraction segment to form a negative pressure. The diameter of the premixing segment is larger than the diameter of the narrowing segment and is smoothly connected to the second segment.

[0012] As a further embodiment, the narrow portion has a throat tube with multiple through holes on its wall, the through holes serving as air inlets, and an ultrafiltration membrane disposed along the inner edge of the throat tube wall, the ultrafiltration membrane being positioned corresponding to the through holes.

[0013] As a further embodiment, a cavity is provided on the outside of the larynx, the cavity is connected to the inside of the larynx through the through hole, and the cavity is provided with a communication port for communicating with the outside.

[0014] As a further embodiment, the communication port is equipped with an air pump.

[0015] As a further embodiment, the throat tubes have the same inner diameter and smoothly transition to the end of the constriction section, and the through holes are arrayed on the throat tubes.

[0016] As a further embodiment, the size of the ultrafiltration membrane is larger than the size of the portion of the throat tube with through holes.

[0017] As an alternative implementation, the second segment includes two flow channels with curvatures greater than a set value, and the flow channels are provided with a confluence at the end, so that the fluids in each flow channel can collide at the confluence to generate vortices.

[0018] As an alternative implementation, the number of flow channels in the second segment is configured according to the volume fraction requirement of the microbubbles; the larger the volume fraction, the more flow channels are required.

[0019] As an alternative implementation, the third segment includes a guide channel connecting the intersection of the second segment, a diverging channel, and a mixing channel. The diameter of the mixing channel is larger than the diameter of the guide channel, and the two ends of the diverging channel are smoothly connected to the guide channel and the mixing channel, respectively.

[0020] The working method of the microbubble generator described above includes the following steps:

[0021] When liquid enters the inlet, it passes through the contraction section, where the liquid velocity increases sharply and the pressure decreases, creating a negative pressure at the air inlet. Negative pressure or external power is used to force air into the narrow section, and the ultrafiltration membrane at the air inlet of the narrow section prevents the fluid from flowing out of the air inlet.

[0022] The gas flowing in at the air inlet generates bubbles. The liquid flows quickly through the narrow section, and the fluid has a certain shear force with the wall, which shears the bubbles. The bubble fluid forms a dense flow of microbubbles with different particle sizes in the divergence section. After passing through the premixing section, the microbubbles and liquid are initially uniformly mixed.

[0023] The premixed liquid mixture is fed into a flow channel based on the principle of a reverse Tesla valve. The fluid is divided into at least two sections in the flow channel. The collision at the junction generates a vortex with a certain turbulent kinetic energy, which further shears and breaks up the bubbles in the fluid to form smaller bubbles.

[0024] After undergoing complete shearing, the microbubble flow exits through the second section. In the third section, the main part of the fluid is concentrated on one side, and the microbubbles aggregate. In the area with less fluid, a certain amount of turbulent kinetic energy eddy is generated, which uniformly disperses the microbubbles on the aggregated side, forming a uniformly dispersed microbubble fluid.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] The invention consists of three parts, and the three parts are ingeniously designed. The first part is a novel Venturi tube with an ultra-microfiltration membrane attached. The ultra-microfiltration membrane is attached at the air inlet, which has good hydrophobicity and the pore size of the membrane is at the micron level, which can block liquids through gas.

[0027] The second section is a reverse Tesla valve principle flow channel. The gas-liquid mixture pretreated in the first section is introduced, and the fluid is divided into two sections in the flow channel. The collision at the junction generates a vortex with strong turbulent kinetic energy, which further shears and breaks down large bubbles in the fluid into smaller bubbles. When a large volume fraction of microbubbles is required, too much gas in the first channel and the first reverse Tesla valve principle flow channel cannot completely break it down into microbubbles of uniform particle size. At this time, the number of flow channels in the second section can be increased to increase the number of shearing operations. The structure is flexible and simple.

[0028] The third section is a microbubble mixing and uniform channel. In this large-diameter channel, the main part of the fluid is concentrated on one side. At this time, microbubbles aggregate and are very prone to coalescence. In the part with less fluid, a large-scale turbulent vortex with low kinetic energy will be generated, which will uniformly disperse the aggregated microbubbles on one side and form a uniformly dispersed microbubble fluid.

[0029] Through the combination of the above-mentioned parts, the present invention can form a uniformly dispersed microbubble fluid, and has a simple structure, high efficiency, small space occupation, and low cost.

[0030] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0031] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0032] Figure 1 This is the overall structure of the microbubble generator in this embodiment;

[0033] Figure 2 This is a partial view of the novel Venturi throat segment of this embodiment;

[0034] Figure 3 This is a schematic diagram of the flow channel structure of the Tesla valve in this embodiment;

[0035] Figure 4 This is a schematic diagram of the flow channel of the Tesla valve in this embodiment;

[0036] Figure 5 This is a cloud map of the gas-liquid phase in the FLUENT simulation of this embodiment.

[0037] Among them, 1. Liquid inlet, 2. Contraction section, 3. Throat, 31. Throat tube, 32. Ultrafiltration membrane, 33. Air inlet, 34. Connecting port, 4. Divergence section, 5. Premixing section, 6. Tesla valve principle flow channel, 61. Tesla valve principle flow channel shaft connection, 62. Tesla valve principle flow channel hole connection, 7. Microbubble mixing uniform channel. Detailed Implementation

[0038] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0039] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0040] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0041] Example 1

[0042] Microbubble generator, such as Figure 1 As shown, it includes a novel Venturi tube with an ultrafiltration membrane, a flow channel based on the reverse Tesla valve principle, and a microbubble mixing and homogenization channel. The fluid undergoes pre-shearing and pre-mixing of bubbles in the first section, further shearing to reduce particle size in the second section, and finally flows out after uniform gas-liquid mixing in the third section.

[0043] The first section is a novel Venturi tube with an ultra-microfiltration membrane. The ultra-microfiltration membrane is attached to the air inlet, which has good hydrophobicity and the pore size of the membrane is on the micrometer scale, allowing gas to pass through while blocking liquid.

[0044] In some embodiments, when the required microbubble volume fraction is small, a self-priming principle can be used, in which case the filter membrane can ensure that the liquid does not flow out at the air inlet; when the required microbubble volume fraction is large, an air pump can be installed at the air inlet. After the gas-liquid mixture is pretreated by the novel Venturi tube, the bubble particle size is different and the gas-liquid mixing is uneven.

[0045] In this embodiment, the first segment includes an inlet 1, a constriction segment 2, a narrow section (or throat 3), a divergence segment 4, and a premixing segment 5 arranged sequentially. The diameter of the narrow section is smaller than the diameter of the inlet 1, and it is smoothly transitioned by the constriction segment 4 to form a negative pressure. The diameter of the premixing segment 5 is larger than the diameter of the narrow section, and it is smoothly connected to the second segment.

[0046] like Figure 2 As shown, the narrow section has a throat tube 31, and the wall of the throat tube 31 is provided with multiple through holes, openings or slits. The through holes, openings or slits serve as air inlets 33. An ultrafiltration membrane 32 is provided along the inner edge of the wall of the throat tube, and the positions of the ultrafiltration membrane 32 and the through holes, openings or slits correspond to each other.

[0047] A cavity is provided on the outside of the larynx tube 31. The cavity is connected to the inside of the larynx tube through the through hole, and the cavity is provided with a communication port 34 for communicating with the outside.

[0048] In some embodiments, an air pump is provided at the connection port 34.

[0049] In some embodiments, the inner diameter of the throat tube 31 is the same and smoothly transitions to the end of the constriction section 4, and the through holes are arrayed on the throat tube 31.

[0050] The second section is a reverse Tesla valve principle flow channel. The gas-liquid mixture pretreated in the first section is introduced, and the fluid is divided into two sections in the flow channel. The collision at the junction generates a vortex with strong turbulent kinetic energy, which further shears and breaks down large bubbles in the fluid into smaller bubbles. When a large volume fraction of microbubbles is required, too much gas in the first channel and the first section of the reverse Tesla valve principle flow channel cannot be completely sheared into microbubbles of uniform particle size. At this time, the number of flow channels in the second section can be increased to increase the number of shearing operations.

[0051] In this embodiment, as Figure 3 As shown, it includes two flow channels with curvature greater than a set value, and the flow channels are provided with a confluence at the end, so that the fluid in each flow channel can collide at the confluence to generate vortices.

[0052] In some embodiments, the curvature is at least greater than 180° to generate eddies and collisions.

[0053] The two flow channels are connected by a Tesla valve principle flow channel shaft 61 before the flow channel and are connected to the premixing section 5 by a contraction section. After the two flow channels meet, they are connected by a Tesla valve principle flow channel hole 61.

[0054] The third section is a microbubble mixing channel. Due to its structure, the fluid flowing out of the second section mainly flows to one side, such as... Figure 4 As shown in the diagram, within this large-diameter flow channel, the main part of the fluid is concentrated on one side. At this point, microbubbles aggregate and are prone to coalescence. In areas with less fluid, a large-scale turbulent vortex with low kinetic energy is generated, which will uniformly disperse the aggregated microbubbles on one side, forming a uniformly dispersed microbubble fluid.

[0055] In some embodiments, each flow channel is a circular flow channel.

[0056] Of course, in other embodiments, the shape and number of each component / channel can also be changed. These are all things that those skilled in the art can easily conceive of and should fall within the scope of protection of this invention.

[0057] Example 2

[0058] The operating method of the microbubble generator provided in Example 1 includes:

[0059] like Figure 4 As shown, the liquid flows into the liquid inlet 1 through the water pump. After passing through the contraction section 2, the liquid flow rate increases sharply and the pressure decreases, forming a negative pressure at the air inlet. When the required microbubble volume fraction is small, this negative pressure can be used to form a self-priming principle to force air into the throat 31. At this time, the filter membrane 32 can ensure that the liquid will not flow out at the air inlet 33. When the required microbubble volume fraction is large, an air pump can be installed at the external connection port 34.

[0060] like Figure 5 As shown, the air entering the channel through the ultrafiltration membrane produces relatively small bubbles due to the narrow pores. In addition, the liquid has a high flow rate and a large shear force between the fluid and the wall, which can further shear the microbubbles. The bubble fluid forms a dense flow of microbubbles with different particle sizes in the divergence section 4. After passing through the premixing section 5, the microbubbles and liquid are initially uniformly mixed.

[0061] The premixed liquid mixture is then introduced into the reverse Tesla valve principle flow channel 6. The fluid is divided into two sections in the flow channel, and the collision at the junction generates a vortex with strong turbulent kinetic energy, which further shears and breaks down large bubbles in the fluid into smaller bubbles. When a large volume fraction of microbubbles is required, the excess gas in the first channel and the first reverse Tesla valve principle flow channel cannot be completely sheared into microbubbles of uniform particle size. At this time, the number of flow channels in the second section can be increased to increase the number of shearing operations.

[0062] After undergoing complete shearing, the microbubble flow exits through the second stage. Due to structural reasons, the fluid mainly flows to one side. In this large-diameter flow channel, the main part of the fluid is concentrated on one side. At this time, the microbubbles aggregate and are prone to coalescence. In the part with less fluid, a large-scale turbulent vortex with low kinetic energy will be generated, which will uniformly disperse the aggregated microbubbles on one side, forming a uniformly dispersed microbubble fluid.

[0063] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art without creative effort within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A microbubble generator, characterized in that, It includes a first section, a second section, and a third section. The first section is a Venturi tube structure, and an ultrafiltration membrane is provided at the air inlet for pre-shearing and pre-mixing of air bubbles. The first section includes an inlet, a contraction section, a narrow section, a divergence section, and a premixing section arranged in sequence. The diameter of the narrow section is smaller than the diameter of the inlet section, and it is smoothly transitioned through the contraction section to form a negative pressure. The diameter of the premixing section is larger than the diameter of the narrow section, and it is smoothly connected to the second section. The narrow section has a throat tube with multiple through holes on its wall, which serve as air inlets. An ultrafiltration membrane is arranged along the inner edge of the throat tube wall, and the ultrafiltration membrane is positioned corresponding to the through holes. The second section is a reverse Tesla valve principle flow channel, including at least two flow channels with confluence, used for further shearing of bubbles; the second section includes two flow channels with curvature greater than a set value, and the flow channels are provided with confluence at the end, so that the fluid in each flow channel can collide at the confluence to generate vortices; the number of flow channels in the second section is configured according to the volume fraction requirement of microbubbles, the larger the volume fraction, the more flow channels there are. The third section is a mixing and homogenization channel, which is connected to all the flow paths of the second section and converges into one channel for uniform dispersion of microbubbles to form microbubble fluid. The third segment includes a guide channel connecting the intersection of the second segment, as well as a diverging channel and a mixing channel. The diameter of the mixing channel is larger than the diameter of the guide channel, and the two ends of the diverging channel are smoothly connected to the guide channel and the mixing channel, respectively.

2. A microbubble generator as described in claim 1, characterized in that, A cavity is provided on the outside of the larynx, which is connected to the inside of the larynx through the through hole, and the cavity is provided with a communication port for communicating with the outside.

3. A microbubble generator as described in claim 2, characterized in that, An air pump is installed at the connection port.

4. A microbubble generator as described in claim 1, characterized in that, The throat tubes have the same inner diameter and smoothly transition to the end of the constriction section, and the through holes are distributed in an array on the throat tubes.

5. A microbubble generator as described in claim 1, characterized in that, The size of the ultrafiltration membrane is larger than the size of the portion of the throat tube with through holes.

6. A method for operating the microbubble generator according to any one of claims 1-5, characterized in that, Includes the following steps: When liquid enters the inlet, it passes through the contraction section, where the liquid velocity increases sharply and the pressure decreases, creating a negative pressure at the air inlet. Negative pressure or external power is used to force air into the narrow section, and the ultrafiltration membrane at the air inlet of the narrow section prevents the fluid from flowing out of the air inlet. The gas flowing in at the air inlet generates bubbles. The liquid flows quickly through the narrow section, and the fluid has a certain shear force with the wall, which shears the bubbles. The bubble fluid forms a dense flow of microbubbles with different particle sizes in the divergence section. After passing through the premixing section, the microbubbles and liquid are initially uniformly mixed. The premixed gas-liquid mixture is introduced into the flow channel based on the principle of a reverse Tesla valve. The fluid is divided into at least two sections in the flow channel. The collision at the junction generates a vortex with a certain turbulent kinetic energy, which further shears and breaks up the bubbles in the fluid into smaller bubbles. After complete shearing, the microbubble flow exits through the second section. In the third section, the main part of the fluid is concentrated on one side, and the microbubbles aggregate. In the part with less fluid, a certain amount of turbulent kinetic energy eddy is generated, which evenly disperses the microbubbles on the aggregated side, forming a uniformly dispersed microbubble fluid.

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