Micro-nano bubble generator and method

Abstract

The invention relates to the technical field of micro-nano bubbles, and discloses a micro-nano bubble generator and method, and the micro-nano bubble generator is characterized in that a venturi tube section is provided with an air inlet structure; the shearing flow channel section comprises a straight pipe section in butt joint with the tail end of the diffusion section, the straight pipe section is symmetrically divided into a first branch pipe section and a second branch pipe section towards the two sides in the liquid flowing direction, the straight pipe section where the branch pipe sections are divided serves as a main pipe section, and the tail end of the main pipe section is symmetrically divided into a first main straight pipe section and a second main straight pipe section; the tail end of the first main straight pipe section is communicated to the first branch pipe section, and the tail end of the second main straight pipe section is communicated to the second branch pipe section; the tail ends of the first branch pipe section and the second branch pipe section are arc-shaped and are communicated with each other; multi-stage cutting, collision and crushing can be carried out on a gas-liquid mixture in a pipeline to form a large number of micro-nano bubbles with small particle sizes, the bubbles are subjected to two-stage intersection collision in the shearing flow channel section, the collision effect can promote breakage and re-dispersion of the bubbles, and therefore more micro-bubbles are generated.

Description

Technical Field

[0001] This invention relates to the field of micro-nano bubble technology, and in particular to a micro-nano bubble generator and method. Background Technology

[0002] Micro- and nanobubble technology is emerging in modern processes and environmental treatments across numerous fields. With its unique physicochemical properties, such as extremely large specific surface area, strong adsorption capacity, and long-term persistence in water, micro- and nanobubble technology demonstrates enormous application potential in water treatment, chemical engineering, food processing, agriculture, biomedicine, and petroleum industries.

[0003] Current micro / nano bubble generators on the market primarily utilize principles such as mechanical stirring, gas diffusion, ultrasonic vibration, microfluidics, and hydraulic cavitation to generate bubbles. However, these existing technologies exhibit numerous limitations in practical applications, including non-uniform bubble size, large bubble diameter, low gas solubility, high energy loss, complex equipment structure, high cost, poor stability, and cumbersome operation. These shortcomings severely restrict the promotion and in-depth application of micro / nano bubble generators in many potential fields.

[0004] Existing technologies include the use of a Venturi tube structure to generate microbubbles. This structure includes a guide orifice, a throttling orifice, and a diffuser orifice. The diameter of the throttling orifice is smaller than that of the guide orifice and the diffuser orifice, respectively. When water flows into the guide orifice, the water flow velocity in the throttling orifice is greater than that in the guide orifice because the diameter of the throttling orifice is smaller. When the water flows from the throttling orifice into the diffuser orifice, the velocity decreases, creating a decompression effect. This causes the dissolved air in the water to overflow and form microbubbles. The formed microbubbles flow out from the diffuser orifice with the water flow. However, this structure produces relatively few microbubbles, with only some air overflowing from the water, and the resulting microbubble particle size is relatively large. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a micro / nano bubble generator and method to solve the above problems.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0007] In a first aspect, a micro / nano bubble generator includes:

[0008] The Venturi tube section includes a constriction section, a throat section, and a diffuser section arranged in sequence, and the throat section is provided with an air intake structure.

[0009] The shear flow channel section has a symmetrical structure, including a straight pipe section that connects to the end of the diffuser section. The straight pipe section branches symmetrically into a first branch pipe section and a second branch pipe section on both sides along the liquid flow direction. The straight pipe section after branching into the branch pipe section serves as the main pipe section. The end of the main pipe section is symmetrically divided into a first main straight pipe section and a second main straight pipe section. The end of the first main straight pipe section is connected to the first branch pipe section, and the end of the second main straight pipe section is connected to the second branch pipe section to achieve liquid convergence and collision on different pipe sections. The ends of the first branch pipe section and the second branch pipe section are arc-shaped and connected to achieve liquid convergence and collision on the two branch pipe sections.

[0010] The bubbles undergo two stages of convergence and collision in the shear channel section, which can further break up the bubbles and prevent them from coalescing. The collision action can promote the breakage and redispersion of the bubbles, thereby generating more microbubbles.

[0011] In a further implementation, an outer shell connects the outer walls of the converging section and the diffuser section. The air intake structure includes a microporous tube, which serves as a throat section connecting the converging section and the diffuser section. An air inlet is provided on the outer shell, through which high-pressure gas is introduced into the outer shell. A gas pump directs the high-pressure gas to the microporous tube within the outer shell, where the liquid flow velocity is highest. The entry of the high-pressure gas into the microporous tube generates a large number of microbubbles, resulting in better bubble generation compared to a conventional Venturi tube structure.

[0012] In a further implementation, a transition section and an acceleration section are connected sequentially between the diffusion section and the straight pipe section. The outer diameter of the transition section is consistent throughout and is the same as the outer diameter at the end of the diffusion section. The acceleration section has a constricted pipe structure.

[0013] In a further implementation, the inner wall of the acceleration tube section is provided with a cutting structure along the circumferential direction to cut the fluid in the liquid.

[0014] In a further implementation, the sum of the outer diameters of the front ends of the first branch pipe and the second branch pipe segment is the same as the outer diameter of the front end of the main pipe.

[0015] In a further implementation, a flow divider is provided at the end of the main pipe, which divides the liquid so that the liquid enters the first main straight pipe section and the second main straight pipe section.

[0016] In a further implementation, the angle between the liquid flow directions at the liquid confluence point in the main straight pipe end and the branch pipe end is greater than 120°.

[0017] In a further implementation, the angle between the liquid flow directions at the junction of the first branch pipe section and the second branch pipe section is less than 90°, and the ends of the first branch pipe section and the second branch pipe section are also connected to the main pipe section. The angle between the liquid flow directions in the main pipe section and the branch pipe section is greater than 120°, and the end of the main pipe section is connected to a funnel-shaped opening to allow the diffusion of micro-nano bubbles.

[0018] In a further implementation, a support plate is provided inside the main pipe section. The support plate has a hollow hemispherical shell structure and is equipped with evenly distributed through holes. The cross-sectional shape of the through holes is set to be rectangular at the middle end and trapezoidal at both ends of the rectangle.

[0019] Secondly, a method for operating a micro / nano bubble generator, employing any of the micro / nano bubble generators described above, includes the following steps:

[0020] The gas entering the throat section initially generates bubbles in the throat section. Then, the liquid in the diffusion section is accelerated through the acceleration section and enters the straight pipe section. In the straight pipe section, the liquid enters the first branch pipe section, the second branch pipe section, and the main pipe section respectively. The end of the first main straight pipe section is connected to the first branch pipe section, and the end of the second main straight pipe section is connected to the second branch pipe section to achieve liquid convergence and collision on different pipe sections. The ends of the first branch pipe section and the second branch pipe section are arranged in an arc shape and connected to achieve liquid convergence and collision on the two branch pipe sections to further generate bubbles.

[0021] The beneficial effects of the present invention are as follows:

[0022] 1. By setting up a Venturi tube section and a shear flow channel section, this invention can achieve multi-stage cutting, collision, and breakage of the gas-liquid mixture in the pipeline, so that the generator can eventually form a large number of micro-nano bubbles with small particle size. The bubbles undergo two stages of convergence and collision in the shear flow channel section, which can further break the bubbles on the one hand, and prevent the bubbles from agglomerating on the other hand. The collision effect can promote the breakage and redispersion of the bubbles, thereby generating more microbubbles.

[0023] 2. In the Venturi tube section of the present invention, the throat section of the Venturi tube section is set as a microporous tube, and an outer shell is connected between the outer walls of the constriction section and the diffuser section. High-pressure gas is introduced to the microporous tube in the outer shell by an air pump. The liquid flow rate is the highest at the microporous tube. The high-pressure gas enters the microporous tube, which can generate a large number of microbubbles. Compared with the ordinary Venturi tube structure, the bubble generation effect is better.

[0024] 3. The micro-nano bubble generator of the present invention has an overall axisymmetric structure, which makes the structural dimensions of the micro-nano bubble generator reasonable and convenient to arrange during use.

[0025] 4. The present invention provides a support plate at the position of the main pipe section. The cross-sectional shape of the through hole on the support plate is adapted to the cross-sectional shape of the Venturi tube, so that the gas-liquid mixture can be further divided into micro-nano bubbles when passing through the support plate. In addition, the support plate is located in the middle of the main pipe section, which can prevent the gas-liquid mixture that has undergone secondary convergence and collision from accumulating and discharging into the funnel mouth through the main pipe section and causing bubble aggregation. Attached Figure Description

[0026] 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.

[0027] Figure 1 This is a schematic diagram of the overall structure of the micro / nano bubble generator in an embodiment of the present invention;

[0028] Figure 2 This is a schematic diagram of the support plate in an embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram of the cross-sectional structure of the support plate in an embodiment of the present invention.

[0030] The diagram exaggerates the spacing or dimensions between parts to show their positions; the diagram is for illustrative purposes only.

[0031] The components are: 1. Constriction section, 2. Microporous tube, 3. Diffusion section, 4. Transition section, 5. Acceleration section, 6. Straight section, 7. Main pipe section, 8. First branch pipe section, 9. Second branch pipe section; 10. Main pipe section, 11. Support plate, 12. Diverter plate; 21. Outer shell, 22. Air inlet, 51. Cutting structure, 71. First main straight pipe section, 72. Second main straight pipe section, 101. Bell mouth, 111. Through hole. Detailed Implementation

[0032] 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 in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0033] Example 1

[0034] In a typical embodiment of the present invention, reference is made to Figures 1-3 As shown, a micro / nano bubble generator includes a venturi tube section, a shear flow channel section, and a main pipe section 10. Liquid and gas generate micro / nano bubbles in the venturi tube section and the shear flow channel section, and are discharged through the main pipe section 10.

[0035] like Figure 1 As shown, the Venturi tube section includes a constriction section 1, a throat section, and a diffuser section 3 arranged sequentially according to the direction of liquid flow. The liquid enters the Venturi tube section through the constriction section 1 and reaches the diffuser section 3 through the throat section.

[0036] An air inlet structure is provided at the throat section, through which gas enters the throat section. When liquid flows through the constricted section of the venturi tube into the throat section, the liquid velocity increases significantly due to the sharp decrease in the cross-sectional area of ​​the pipe. According to Bernoulli's equation, the increase in velocity leads to a decrease in liquid pressure. When the pressure in the throat section decreases to a certain level, below the saturated vapor pressure of the dissolved gas in the liquid, the dissolved gas will precipitate and form bubbles; this phenomenon is called cavitation. The cavitation effect not only generates bubbles but also produces localized high temperatures and pressures when the bubbles collapse, further refining the bubbles to micro- and nano-scale.

[0037] Simultaneously, in the throat section, the liquid velocity reaches its maximum, and gas is drawn in through the intake structure and mixed with the liquid. Due to the high-speed flow of the liquid, a strong shearing force is exerted on the gas, cutting it into tiny bubbles. For example, the throat section design of a Venturi tube can significantly increase the liquid velocity, thereby enhancing the shearing force and making it easier for the gas to be dispersed into microbubbles.

[0038] Furthermore, when the gas-liquid mixture enters the diffusion section, the fluid velocity decreases and the pressure rises as the cross-sectional area of ​​the pipe gradually increases, while turbulence is generated.

[0039] The velocity gradient and eddies in turbulence further break up the bubbles, making them smaller and thus generating microbubbles.

[0040] Understandably, the generation efficiency and quality of microbubbles can be further improved by optimizing the geometric parameters of each segment of the Venturi tube (such as throat diameter and diffusion angle).

[0041] In summary, when used as a microbubble generator, the Venturi tube effectively generates microbubbles by inducing cavitation through increased liquid flow velocity and decreased pressure, combined with shearing and turbulence effects.

[0042] like Figure 1 As shown, in order to further improve the microbubble generation efficiency, an outer shell 21 is connected between the outer walls of the constriction section and the diffusion section, so that a sealed space is formed between the throat section and the outer shell 21.

[0043] The air intake structure includes a microporous tube 2 and an air inlet 22 disposed on the outer shell. The microporous tube 2 serves as a throat section to connect the constriction section 1 and the diffuser section 3. The outer shell 21 is connected to an air pump through the air inlet 22, so that high-pressure gas enters the sealed space through the outer shell 21 and then enters the interior of the microporous tube 2.

[0044] By setting up a microporous tube 2, the high-pressure gas can enter the microporous tube 2 and flow out through the micropores by utilizing the pressure difference between the high-pressure gas outside the microporous tube 2 and the liquid inside the microporous tube 2. These gas bubbles are further broken up and refined by the shear force of the liquid at the throat section, and finally form microbubbles.

[0045] In this embodiment, the microporous tube 2 is preferably a ceramic microporous membrane tube, which generally outperforms metal microporous membrane tubes in terms of bubble generation performance and physicochemical properties, and can generate smaller and more uniformly distributed bubbles. Simultaneously, the design of the microporous tube 2 and the liquid flow rate also affect the generation efficiency and quality of microbubbles. For example, at higher flow rates, the shearing effect of the liquid is enhanced, which helps to further refine the bubbles. By setting the throat section of the Venturi tube as a microporous tube, the liquid flow rate is highest at the microporous tube, and high-pressure gas enters the microporous tube, allowing a large number of microbubbles to be generated there.

[0046] like Figure 1 As shown, the venturi tube section is connected downstream to the shear channel section. Specifically, the diffuser section 3 and the straight pipe section 6 of the shear channel section are connected in sequence to a transition section 4 and an acceleration section 5. The outer diameter of the transition section is consistent throughout and is the same as the outer diameter of the end of the diffuser section 3, serving as a transition. The outer diameter of the front end of the acceleration section 5 is larger than that of the rear end, forming a constricted pipe structure to increase the flow velocity of the liquid inside the pipe.

[0047] The inner wall of the acceleration tube section 5 is provided with a cutter structure 51 to cut the fluid in the liquid. The cutter structure 51 is a cutter provided on the inner wall of the tube section along the circumferential direction, so as to further shear the gas-liquid mixture flowing through the acceleration tube section based on the formation of a large number of microbubbles in the Venturi tube section.

[0048] like Figure 1 As shown, the shear flow channel section has a symmetrical structure, including a straight pipe section 6 that connects to the end of the acceleration pipe section 5. The straight pipe section branches symmetrically into a first branch pipe section 8 and a second branch pipe section 9 along the direction of liquid flow. The straight pipe section 6 after branching into the branch pipe section serves as the main pipe section 7. The end of the main pipe section 7 is symmetrically divided into a first main straight pipe section 71 and a second main straight pipe section 72. The end of the first main straight pipe section 71 is connected to the first branch pipe section 8, and the end of the second main straight pipe section 72 is connected to the second branch pipe section 9 to achieve liquid convergence and collision on different pipe sections.

[0049] Specifically, the sum of the outer diameters of the front ends of the first branch pipe end 8 and the second branch pipe section 9 is the same as the outer diameter of the front end of the main pipe end. The main pipe section 7 after branching is coaxially arranged with the straight pipe section 6. The gas-liquid mixture in the straight pipe section 6 is divided into three paths and enters the first branch pipe section 8, the second branch pipe section 9 and the main pipe section 7 respectively.

[0050] like Figure 1 As shown, the end of the main pipe section is symmetrically divided into a first main straight pipe section 71 and a second main straight pipe section 72. A flow divider 12 is provided at the end of the main pipe section. The flow divider 12 divides the gas-liquid mixture so that the gas-liquid mixture enters the first main straight pipe section 71 and the second main straight pipe section 72.

[0051] The ends of the first main straight pipe section 71 and the second main straight pipe section 72 are arranged in an arc shape and extend to the middle of the first branch pipe section 8 and the second branch pipe section 9, respectively. Specifically, the end of the first main straight pipe section 71 is connected to the first branch pipe section 8, and the end of the second main straight pipe section 72 is connected to the second branch pipe section 9 to realize the convergence and collision of gas-liquid mixtures on different pipe sections.

[0052] The diameters of the first main straight pipe section 71, the second main straight pipe section 72, the first branch pipe section 8, and the second branch pipe section 9 are all the same.

[0053] When a gas-liquid mixture in two pipe sections (a branch pipe section and a main straight pipe section) meets and collides at the connection point, a strong shear force is generated. This shear force can further shear larger bubbles into smaller microbubbles. It can break bubbles within the gas-liquid mixture down to tens of nanometers to several micrometers.

[0054] In the collision zone, the flow state of the fluid typically becomes very complex, forming turbulence. The intense mixing effect of turbulence allows for more thorough contact between gas and liquid, increasing the surface area of ​​the gas-liquid interface and thus promoting the formation of microbubbles. This turbulent mixing also enables newly formed microbubbles to disperse rapidly into the liquid, preventing them from agglomerating and growing.

[0055] At the junction of two pipe sections (branch section and main straight section), the local pressure at the junction changes due to fluid collisions and changes in flow direction. This pressure change can promote the bursting and redispersion of bubbles, thereby generating more microbubbles.

[0056] Furthermore, when the gas-liquid mixture converges at the interface, collisions between bubbles and between bubbles and liquid increase. These collisions can lead to bubble breakage, thereby generating more microbubbles. This structural design in this embodiment can significantly improve the microbubble generation efficiency.

[0057] In summary, when gas-liquid mixtures in two connected pipes collide at the junction, mechanisms such as shearing, turbulent mixing, pressure changes, and collisional breakup can generate more microbubbles within the pipe. These mechanisms work together to significantly improve the generation efficiency and quality of microbubbles. At the junction of pipes, not only is the amount of bubble generated increased, but the resulting bubbles also have smaller particle sizes.

[0058] Furthermore, the ends of the first branch pipe segment 8 and the second branch pipe segment 9 are arranged in an arc shape and connected to achieve liquid exchange and collision on the two branch pipe segments.

[0059] The gas-liquid mixture in the first main straight pipe section 71 and the second main straight pipe section 72 converges into the first branch pipe section 8 and the second branch pipe section 9, resulting in a first-level convergence collision in the shear flow channel section. The gas-liquid mixture travels along the first branch pipe section 8 and the second branch pipe section 9 to the end, where it converges and collides again, resulting in a second-level convergence collision.

[0060] The ends of the first branch pipe section 8 and the second branch pipe section 9 are also connected to the main pipe section 10. The end of the main pipe section is connected to the flared end 101 so that the micro-nano bubbles can diffuse. The gas-liquid mixture after the secondary convergence and collision is discharged from the micro-nano bubble generator through the main pipe section 10 and the flared end 101.

[0061] The principle of secondary collision is similar to that of primary collision. After two-stage collisions in the shear channel section, a large number of micro- and nano-bubbles can be generated.

[0062] In a preferred embodiment, the angle between the liquid flow directions at the liquid confluence point of the main straight pipe end and the branch pipe end is greater than 120°, such as... Figure 1 As shown, the included angle is greater than 120°, which makes the collision effect of the liquid carrying air bubbles in the main straight pipe end and the branch pipe end more obvious, and the effects of shearing, turbulent mixing, pressure change, collision and breaking mechanisms are stronger.

[0063] like Figure 1 As shown, the combined shape of the two branch pipe sections is heart-shaped. The flow direction of the gas-liquid mixture at the ends of the branch pipe sections makes an angle greater than 120° with the direction of discharge along the main pipe section, which also makes the mutual collision effect obvious.

[0064] It is understandable that the angle between the liquid flow directions at the junction of the first branch pipe section 8 and the second branch pipe section 9 is less than 90°.

[0065] The gas-liquid mixture passes through the shear channel section, forming a large number of micro- and nano-bubbles. To further shear these bubbles, such as... Figure 1 As shown, a support plate 11 is provided inside the main pipe section 10. The support plate 11 has a hollow hemispherical shell structure and through holes 111 are evenly distributed on the support plate. The cross-sectional shape of the through holes 111 is set to be rectangular at the middle end and trapezoidal at both ends of the rectangle.

[0066] like Figure 3 As shown, the cross-sectional shape of the through-hole 111 is similar to that of a Venturi tube. By providing the support plate 11, the gas-liquid mixture within the main pipe section 10 can be further sheared into a large number of micro- and nano-bubbles. It is understood that in some examples, since the amount of micro- and nano-bubbles generated within the shearing channel section is already sufficient, the support plate 11 may not be necessary.

[0067] In a preferred embodiment, the support plate is located in the middle of the main pipe section 10 to prevent the coalescence of bubbles during the process of the gas-liquid mixture passing through the main pipe section 10 to the bell mouth 101 after secondary convergence and collision. In addition, since the support plate 11 has a hollow hemispherical shell structure, the axes of the through holes on the support plate 11 are different, which makes the flow direction of the gas-liquid mixture passing through the support plate 11 different. The gas-liquid mixture passing through the support plate 11 may collide and rebound at the inner wall of the main pipe section 10, where a certain degree of gas-liquid mixture convergence and collision can occur.

[0068] Example 2

[0069] In a typical embodiment of the present invention, reference is made to Figures 1-3 As shown, a method for operating a micro / nano bubble generator, which employs the micro / nano bubble generator described in Example 1, includes the following steps:

[0070] The liquid enters the constriction section 1 of the venturi tube section, and then reaches the microporous tube section 2 at the throat section. High-pressure gas enters the outer shell 21 through the air inlet, and then enters the microporous tube section 2. Bubbles are initially generated at the inner side of the microporous tube section 2 due to shearing action. After that, the liquid in the diffusion section 3 enters the acceleration section 5 after passing through the transition section 4. After being accelerated in the acceleration section 5, it enters the straight tube section 6.

[0071] The gas-liquid mixture in the pipeline is cut into bubbles at the acceleration section 5. Then, the liquid (gas-liquid mixture) in the straight pipe section 6 enters the first branch pipe section 8, the second branch pipe section 9, and the main pipe section 7 respectively. The gas-liquid mixture in the main pipe section 7 enters the first main straight pipe section 71 and the second main straight pipe section 72. The end of the first main straight pipe section 71 is connected to the first branch pipe section 8, and the end of the second main straight pipe section 72 is connected to the second branch pipe section 9 to achieve liquid convergence and collision on different pipe sections (first-level convergence and collision). The ends of the first branch pipe section 8 and the second branch pipe section 9 are arranged in an arc shape and connected to achieve liquid convergence and collision on the two branch pipe sections (second-level convergence and collision) to further generate micro-nano bubbles. Then, the gas-liquid mixture is subjected to the action of the support plate 11 on the main pipe section 10 to generate a large number of micro-nano bubbles with smaller diameters.

[0072] 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 within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A micro / nano bubble generator, characterized in that, include: The Venturi tube section includes a constriction section, a throat section, and a diffuser section arranged in sequence, and the throat section is provided with an air intake structure. The shear flow channel section has a symmetrical structure, including a straight pipe section that connects to the end of the diffuser section. The straight pipe section branches symmetrically into a first branch pipe section and a second branch pipe section on both sides along the liquid flow direction. The straight pipe section after branching into the branch pipe section serves as the main pipe section. The end of the main pipe section is symmetrically divided into a first main straight pipe section and a second main straight pipe section. The end of the first main straight pipe section is connected to the first branch pipe section, and the end of the second main straight pipe section is connected to the second branch pipe section to achieve liquid convergence and collision on different pipe sections. The ends of the first branch pipe section and the second branch pipe section are arc-shaped and connected to achieve liquid convergence and collision on the two branch pipe sections.

2. The micro / nano bubble generator according to claim 1, characterized in that, An outer shell is connected between the outer walls of the constriction section and the diffuser section. The air intake structure includes a microporous tube, which serves as a throat section to connect the constriction section and the diffuser section. An air inlet is provided on the outer shell, through which high-pressure gas is introduced into the outer shell.

3. The micro / nano bubble generator according to claim 1, characterized in that, The diffusion section and the straight pipe section are connected in sequence by a transition section and an acceleration pipe section. The outer diameter of the transition section is consistent throughout and is the same as the outer diameter of the end of the diffusion section. The acceleration pipe section has a constricted pipe structure.

4. A micro / nano bubble generator according to claim 3, characterized in that, The inner wall of the acceleration tube section is provided with a cutting structure along the circumferential direction to cut the fluid in the liquid.

5. A micro / nano bubble generator according to claim 4, characterized in that, The sum of the outer diameters of the front ends of the first branch pipe and the second branch pipe section is the same as the outer diameter of the front end of the main pipe.

6. A micro / nano bubble generator according to claim 1, characterized in that, A flow divider is provided at the end of the main pipe to divide the liquid so that the liquid enters the first main straight pipe section and the second main straight pipe section.

7. A micro / nano bubble generator according to claim 6, characterized in that, The angle between the liquid flow directions at the point where the liquids meet in the main straight pipe end and the branch pipe end is greater than 120°.

8. A micro / nano bubble generator according to claim 1, characterized in that, The angle between the liquid flow directions at the junction of the first and second branch pipe sections is less than 90°. The ends of the first and second branch pipe sections are also connected to the main pipe section. The angle between the liquid flow directions in the main pipe section and the branch pipe section is greater than 120°. The end of the main pipe section is connected to a funnel-shaped opening to allow the diffusion of micro-nano bubbles.

9. A micro / nano bubble generator according to claim 8, characterized in that, The main pipe section is equipped with a support plate, which is a hollow hemispherical shell structure. The support plate has through holes evenly distributed on it, and the cross-sectional shape of the through holes is set to be rectangular at the middle end and trapezoidal at both ends of the rectangle.

10. A method for operating a micro / nano bubble generator, characterized in that, The micro / nano bubble generator as described in any one of claims 1-9 comprises the following steps: The gas entering the throat section initially generates bubbles in the throat section. Then, the liquid in the diffusion section is accelerated through the acceleration section and enters the straight pipe section. In the straight pipe section, the liquid enters the first branch pipe section, the second branch pipe section, and the main pipe section respectively. The end of the first main straight pipe section is connected to the first branch pipe section, and the end of the second main straight pipe section is connected to the second branch pipe section to achieve liquid convergence and collision on different pipe sections. The ends of the first branch pipe section and the second branch pipe section are arranged in an arc shape and connected to achieve liquid convergence and collision on the two branch pipe sections to further generate bubbles.

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