Particle size controllable micro-nano bubble generation device and regulation and control method

Abstract

The invention discloses a particle size controllable micro-nano bubble generation device and a regulation and control method. The micro-nano bubble generation device comprises an initial bubble generation assembly and a bubble refining and dispersing assembly. The initial bubble generation assembly comprises a gas cylinder (1), a liquid tank (2), a gas-liquid mixing valve (3), a bubble generation core unit (4) and a bubble homogenizing mixer (5); the bubble refining and dispersing assembly comprises an electric telescopic table (6), an ultrasonic signal generator (7), a signal amplifier (8), an ultrasonic generating probe (9) and a water storage tank (10) used for containing a micro-nano bubble dispersing system. Initial micro-nano bubbles are generated by utilizing a bubble generation core unit (4), then primary bubbles are generated under the action of sound field standing waves on the basis of a Helmholtz resonance effect through an ultrasonic radiation generation probe (9) arranged above a gas-liquid interface, and the primary bubbles are broken into sub-bubbles with smaller particle sizes through an acoustic rupture mechanism. Therefore, accurate control of bubble particle size is realized.

Description

Technical Field

[0001] This invention belongs to the field of micro-nano bubble preparation technology, specifically relating to a micro-nano bubble generating device and control method with controllable particle size. Background Technology

[0002] Micro- and nanobubble technology, as a highly efficient gas-liquid dispersion method, has shown broad application prospects in environmental remediation, biomedicine, industrial cleaning, and agricultural irrigation. Micro- and nanobubbles typically refer to bubbles with a particle size ranging from 1 nm to 100 μm, possessing advantages such as large specific surface area, long residence time, and high mass transfer efficiency, significantly enhancing gas-liquid reaction processes. However, the practical application effect of micro- and nanobubble technology is highly dependent on the particle size distribution and controllability of the bubbles. Ideally, micro- and nanobubbles should possess characteristics of small particle size, uniform distribution, and controllability to ensure their stability, functionality, and applicability. However, existing micro- and nanobubble preparation methods still suffer from bottlenecks such as a large average particle size of bubbles generated in a single step, a wide and uncontrollable particle size distribution, which severely restricts the promotion and optimization of this technology.

[0003] Currently, mainstream methods for preparing micro / nano bubbles mainly include pressure dissolved gas release, hydraulic cavitation, electrolysis, microchannel methods, and ultrasonic cavitation. Pressure dissolved gas release generates bubbles by rapidly releasing pressure after dissolving gas under high pressure, but the bubble size is easily affected by pressure fluctuations, making precise control difficult. Hydraulic cavitation generates bubbles using fluid shear or eddy cavitation, but the bubble size is generally large and lacks uniformity. Electrolysis generates bubbles through electrochemical reactions, but it is energy-intensive and has limited bubble production. Microchannel methods prepare monodisperse bubbles based on microfluidic technology, but the equipment is complex, costly, and prone to clogging. Ultrasonic cavitation generates bubbles by inducing cavitation effects using an immersion ultrasonic probe, but the bubble size is limited by the cavitation intensity, and direct probe contact with the liquid may lead to contamination or wear. Furthermore, these methods all focus on a single generation process and lack subsequent refinement mechanisms for the generated bubbles, resulting in uncontrollable bubble size and difficulty in meeting the precision requirements of different application scenarios.

[0004] Of particular note is that while existing ultrasonic cavitation methods can generate micro- and nano-bubbles, their mechanism relies on the cavitation effect within the liquid, requiring the probe to be immersed in the liquid to initiate cavitation. This method cannot achieve active control over bubble size, and the generated nanocrystals may interfere with bubble stability. In contrast, the ultrasonic mechanism introduced in this invention is entirely different: by placing the ultrasonic radiation-generating probe above the gas-liquid interface, the generated bubbles are further refined using the standing wave effect and acoustic rupture mechanism. This design not only avoids the problems caused by probe contact with the liquid but also allows for precise control of particle size by adjusting the acoustic field parameters, overcoming the shortcomings of existing technologies.

[0005] In summary, existing micro / nano bubble generation methods have significant shortcomings in terms of particle size controllability. The generated bubbles are often too large and unevenly distributed, affecting the performance of micro / nano bubble technology in high-end applications. Therefore, there is an urgent need to develop a micro / nano bubble generation method and device that is compatible with various existing generators and enables active control of bubble particle size, in order to improve bubble uniformity and stability and promote the innovative development of micro / nano bubble technology. Summary of the Invention

[0006] The purpose of this invention is to provide a micro / nano bubble generator with controllable particle size, so as to solve the problems of large average particle size of bubbles generated in one step, uncontrollable bubble size, and uneven distribution in existing micro / nano bubble preparation methods.

[0007] Another objective of this invention is to provide a method for generating and controlling micro / nano bubbles with controllable particle size.

[0008] To achieve the above-mentioned objectives of the present invention, the present invention provides a micro / nano bubble generating device with controllable particle size, comprising an initial bubble generating component (primary generating component) and a bubble refining and dispersing component (secondary refining component). The primary generating component is used to generate initial micro / nano bubbles, and the secondary refining component performs secondary processing on the initial micro / nano bubbles through ultrasonic action to optimize the particle size distribution.

[0009] The initial bubble generation assembly includes a gas cylinder, a liquid tank, a gas-liquid mixing valve, a bubble generation core unit, and a bubble homogenizer. The gas cylinder and liquid tank are connected to the gas-liquid mixing valve via connecting pipes. The gas-liquid mixing valve is connected to the bubble generation core unit via a gas-liquid delivery pipe. The bubble generation core unit is connected to the bubble homogenizer via a bubble delivery pipe. The bubble homogenizer is equipped with spiral blades inside. After the gas in the gas cylinder and the liquid in the liquid tank are mixed through the gas-liquid mixing valve, they flow into the bubble generation core unit to generate initial micro-nano bubbles. The generated initial micro-nano bubbles flow into the bubble homogenizer, where the spiral blades inside achieve uniform mixing and stable release of the bubbles. They then enter a water storage tank to form a micro-nano bubble dispersion system.

[0010] The bubble refining and dispersion assembly includes an electric telescopic platform, an ultrasonic signal generator, a signal amplifier, an ultrasonic generating probe, and a water tank for containing the micro / nano bubble dispersion system. Two electric telescopic platforms are respectively installed on the top and bottom plates of the water tank. The ultrasonic generating probe is vertically positioned above the gas-liquid interface of the water tank via the electric telescopic platform located on the top plate. The ultrasonic signal generator is connected to the ultrasonic generating probe via the signal amplifier. The ultrasonic signal generator generates a frequency range controlled from 65.26 kHz to 6.526 GHz, and the signal amplifier adjusts the sound pressure to 0.5 MPa to 10 MPa. Ultrasonic waves are generated by the ultrasonic generating probe positioned above the gas-liquid interface of the water tank. The distance between the ultrasonic generating probe and the liquid surface is adjusted to an integer multiple of half the wavelength of the ultrasonic wave (e.g., λ / 2, λ, or 3λ / 2) to form a stable standing wave. The acoustic radiation pressure generated by the standing wave causes pits to form on the liquid surface. These pits resonate under the influence of the sound field, causing the interface to close and break downwards, forming primary bubbles that detach from the gas-liquid interface and enter the liquid. This mechanism provides a continuous source of initial bubbles for the subsequent refinement process.

[0011] The outlet of the bubble homogenizer in the initial bubble generation component is connected to the inlet of the water tank in the bubble refining and dispersing component via a pipeline.

[0012] Preferably, the bubble generation core unit can be selected from the following devices according to different preparation methods: a dissolved gas release device for pressure dissolved gas release method, a venturi tube for hydraulic cavitation method, a vortex cavitation bubble breaker or multi-stage decompression and gas release structure, an electrode plate for electrolysis method, a microfluidic chip or microchannel device for microchannel method, or an ultrasonic transducer for ultrasonic cavitation method.

[0013] Preferably, a pressure reducing valve and a flow meter are respectively installed on the connecting pipeline between the gas cylinder, the liquid tank and the gas-liquid mixing valve to control the flow rate of the gas and the liquid.

[0014] Preferably, the electric telescopic platform is equipped with a position feedback system, which can monitor and adjust the distance H between the ultrasonic generator probe and the liquid surface in real time to ensure that H is an integer multiple of half the wavelength of the ultrasonic wave, so as to form a stable sound field standing wave.

[0015] The present invention provides a method for generating and controlling micro / nano bubbles with controllable particle size, comprising the following steps:

[0016] S1, gas-liquid mixture

[0017] Gas and liquid sources are provided by gas cylinders and liquid tanks respectively, and they are mixed in a set ratio through a gas-liquid mixing valve to form a mixed gas-liquid mixture.

[0018] S2, Initial micro / nano bubble generation

[0019] The mixed gas and liquid flow into the bubble generation core unit to generate initial micro-nano bubbles;

[0020] S3, average initial micro / nano bubble dispersion

[0021] The generated initial micro- and nano-bubbles then flow into a bubble homogenizer, where the helical motion of the helical blades promotes the uniform dispersion and stable release of the bubbles, preventing the micro- and nano-bubbles from agglomerating.

[0022] S4, Formation of gas-liquid dispersion system

[0023] After being dispersed and averaged, the micro-nano bubbles flow into the water storage tank, forming a micro-nano bubble gas-liquid dispersion system;

[0024] S5, Ultrasonic Control

[0025] Ultrasonic waves are generated by an ultrasonic probe placed above the gas-liquid interface of the water storage tank. Based on the Helmholtz resonance effect, primary bubbles are generated on the liquid surface under the action of the sound field standing wave. The distance between the ultrasonic probe and the liquid surface is adjusted to adjust the half wavelength of the ultrasonic wave to an integer multiple to form a stable sound field standing wave.

[0026] S6, Acoustic fracture refinement of particle size

[0027] Ultrasonic waves are generated by an ultrasonic signal generator, and the primary bubbles generated are broken into smaller sub-bubbles through an acoustic rupture mechanism. By adjusting the ultrasonic parameters and the distance between the ultrasonic generator probe and the liquid surface, the particle size of micro- and nano-bubbles can be precisely controlled.

[0028] The sound-to-fracture refinement method is modulated by the position of micro / nano bubbles in the sound field:

[0029] Mode 1 (Thin Film Outward Folding): When the bubble is directly below the ultrasonic transducer, the bubble's liquid film rapidly retracts towards the edge, folds outward under inertia, and breaks off, forming a ring-shaped sub-bubble string. This process is dominated by inertial effects, with a calculated Reynolds number (Re) of approximately 10. 3 >>1 indicates that the inertial force is much greater than the viscous force, supporting the folding and pinching behavior of the liquid film. The Reynolds number expression is:

[0030]

[0031] In the formula: ρ is the liquid density, kg / m³ 3 R is the radius of the primary bubble, m; U is the recoil velocity of the liquid film, m / s; μ is the dynamic viscosity of the liquid, Pa·s;

[0032] Mode 2 (film inward folding): When the bubble deviates from the center of the ultrasonic probe, it is attracted by the sound field, causing the liquid film to fold inward, enveloping the air and forming multiple small sub-bubbles. Acoustic radiation force dominates, and the calculated acoustic Bond number (Boa) is Bo. a >>1 indicates that the acoustic radiation force overcomes the surface tension, causing the bubble to become unstable and rupture. The expression for the acoustic Bond number is:

[0033]

[0034] In the formula: v rms σ is the root mean square value of the vibration velocity of the medium particles, in m / s; σ is the surface tension of the liquid, in N / m.

[0035] The ultrasonic frequency was determined based on the Minnaert frequency formula for micro / nanobubbles, ranging from 65.26 kHz to 6.526 GHz, to ensure efficient energy transfer and induce bubble collapse. The Minnaert frequency formula is:

[0036]

[0037] In the formula: R0 is the equilibrium radius of the micro / nano bubble, m; γ is the specific heat ratio of the gas inside the bubble, taken as 1.4 for air; P0 is the static pressure acting on the micro / nano bubble, Pa; ρ is the liquid density, kg / m³. 3 .

[0038] This invention discloses a micro / nano bubble generator and its control method with controllable particle size. By introducing a two-stage ultrasonic refinement mechanism, the device achieves active control over the particle size of micro / nano bubbles, improving bubble uniformity and stability. Furthermore, this method can be used in conjunction with various existing micro / nano bubble generators, exhibiting strong versatility and application flexibility. Specifically, it has the following beneficial effects:

[0039] (1) Through the ultrasonic two-stage refinement mechanism, the particle size of micro-nano bubbles is actively controlled to make their distribution more uniform and the particle size range can be accurate to the nanometer level to meet the needs of different application scenarios.

[0040] (2) The method of the present invention can be seamlessly integrated with existing generators such as pressure dissolved gas release method, hydraulic cavitation method, electrolysis method, microchannel method and ultrasonic cavitation method. No core unit needs to be modified. Upgrades can be achieved by adding secondary refinement components, which reduces application costs.

[0041] (3) The spiral blades inside the bubble homogenizer ensure uniform release of bubbles and reduce agglomeration; the acoustic rupture mechanism under ultrasonic action enhances the dynamic stability of bubbles and prolongs the residence time.

[0042] (4) The distance between the probe and the liquid surface can be adjusted in real time by the electric telescopic platform, and combined with the digital control of ultrasonic parameters (such as frequency and sound pressure), automated operation can be achieved to adapt to various working conditions.

[0043] (5) The ultrasonic energy is concentrated on the gas-liquid interface, avoiding ineffective cavitation, with low energy consumption and no pollution, which meets the requirements of green manufacturing.

[0044] This invention achieves active and precise control of micro- and nano-bubble particle size through the above-described method and apparatus, providing reliable technical support for applications in environmental remediation, biomedicine, industrial cleaning, and other fields. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the overall structure of a micro / nano bubble generator with controllable particle size according to the present invention.

[0046] Figure 2 This is a schematic diagram illustrating the workflow of a method for generating and controlling micro / nano bubbles with controllable particle size according to the present invention.

[0047] Figure 3 This is a schematic diagram of the internal structure of the bubble homogenizer used in the micro / nano bubble generator with controllable particle size according to the present invention.

[0048] Figure 4 This is a schematic diagram of the connection of the ultrasonic generator used in the micro / nano bubble generator with controllable particle size according to the present invention.

[0049] Figure 5 This is the dissolved gas release device corresponding to the pressure dissolved gas release method in the core unit for bubble generation of the present invention.

[0050] Figure 6 This is a multi-stage decompression and gas release structure corresponding to the hydraulic cavitation method in the core unit for bubble generation of the present invention.

[0051] Figure 7 The Venturi tube used in the core bubble generation unit of this invention corresponds to the hydraulic cavitation method.

[0052] Figure 8 This invention relates to a vortex cavitation bubble breaker that uses the hydraulic cavitation method in the core unit for bubble generation.

[0053] Figure 9 This refers to the electrode plate used in the core unit for bubble generation in this invention, which employs an electrolysis method.

[0054] Figure 10 This refers to the microchannel device corresponding to the microchannel method used in the core unit for bubble generation of the present invention.

[0055] Figure 11This refers to the ultrasonic transducer corresponding to the ultrasonic cavitation method used in the bubble generation core unit of the present invention.

[0056] The attached diagram is labeled as follows: 1-Gas cylinder; 2-Liquid tank; 3-Gas-liquid mixing valve; 4-Bubble generation core unit; 5-Bubble homogenizer; 6-Electric telescopic platform; 7-Ultrasonic signal generator; 8-Signal amplifier; 9-Ultrasonic probe; 10-Water storage tank; 11-Helical blade. Detailed Implementation

[0057] The following will describe in more detail, with reference to the accompanying drawings of the embodiments of the present invention, a micro / nano bubble generator and control method with controllable particle size. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0058] Depend on Figure 1 The diagram shown is a schematic representation of the overall structure of a micro / nano bubble generator with controllable particle size according to the present invention, combined with... Figure 3 , Figure 4 As can be seen, the micro-nano bubble generating device with controllable particle size of the present invention includes an initial bubble generation component and a bubble refining and dispersing component. The overall structure is compact and easy to operate, and it can realize the active control of micro-nano bubble particle size.

[0059] The initial bubble generation component (initial bubble primary generation component) includes a gas cylinder 1, a liquid tank 2, a gas-liquid mixing valve 3, a bubble generation core unit 4, and a bubble homogenizer 5. The gas cylinder 1 and liquid tank 2 are connected to the gas-liquid mixing valve 3 via connecting pipes. The gas-liquid mixing valve 3 is connected to the bubble generation core unit 4 via a gas-liquid delivery pipe. The bubble generation core unit 4 is connected to the bubble homogenizer 5 via a bubble delivery pipe. The bubble homogenizer 5 is equipped with spiral blades 11 inside. The design of the spiral blades 11 enhances the turbulence effect, making the bubbles more evenly distributed in the liquid. The homogenized micro-nano bubble water flows into the water storage tank 10 in the bubble refining and dispersion component (secondary refining component), forming a micro-nano bubble dispersion system. The bubble generation core unit 4 can be equipped with appropriate devices depending on the preparation method, such as a dissolved gas release device for pressure dissolved gas release, a Venturi tube or vortex cavitation bubble breaker for hydraulic cavitation, an electrode plate for electrolysis, a microfluidic chip for microchannel method, or an ultrasonic transducer for ultrasonic cavitation method. These devices can generate initial micro-nano bubbles, but they suffer from uneven particle size distribution. Pressure reducing valves and flow meters (not shown in the figure) are respectively installed on the connecting pipelines between the gas cylinder 1, liquid tank 2, and gas-liquid mixing valve 3 to control the flow rates of gas and liquid, ensuring a stable gas-liquid mixing ratio. For example, the gas flow rate can be controlled at 0.00288 m³ / s.3 / h~0.0033m 3 The liquid flow rate can be controlled at 0.0168 m³ / h. 3 / h~0.0192m 3 / h, to achieve the best mixing effect. Gas cylinder 1 and liquid tank 2 serve as the gas source and water source for preparing micro-nano bubbles, respectively. Gas cylinder 1 can be filled with air, oxygen, ozone or other functional gases, selected according to application requirements; liquid tank 2 stores deionized water, tap water or a specific solution.

[0060] The bubble refining and dispersion component (secondary refining component) includes an electric telescopic platform 6, an ultrasonic signal generator 7, a signal amplifier 8, an ultrasonic generating probe 9, and a water tank 10 for containing the micro-nano bubble dispersion system. Two electric telescopic platforms 6 are respectively installed on the top and bottom plates of the water tank 10. The ultrasonic generating probe 9 is vertically arranged above the gas-liquid interface of the water tank 10 via the electric telescopic platform 6 located on the top plate of the water tank 10. The ultrasonic signal generator 7 is connected to the ultrasonic generating probe 9 through the signal amplifier 8. The ultrasonic signal generator 7 generates a frequency range controlled from 65.26 kHz to 6.526 GHz, and the signal amplifier 8 adjusts the sound pressure to 0.5 MPa to 10 MPa. The electric telescopic platform 6 is equipped with a position feedback system, which can monitor and adjust the distance H between the ultrasonic generating probe 9 and the liquid surface in real time, ensuring that H is an integer multiple of half the wavelength of the ultrasonic wave to form a stable standing wave.

[0061] The outlet of the bubble homogenizer 5 in the initial bubble generation component is connected to the inlet of the water tank 10 in the bubble refining and dispersing component via a pipeline.

[0062] Depend on Figure 2 The schematic diagram of the workflow of the method for generating and controlling micro / nano bubbles with controllable particle size of the present invention shows that the method includes the following steps:

[0063] S1, gas-liquid mixture

[0064] Gas source 1 and liquid source 2 are provided by gas cylinder 1 and liquid tank 2 respectively. They are mixed in a set ratio through gas-liquid mixing valve 3 to form a mixed gas-liquid mixture.

[0065] S2, Initial micro / nano bubble generation

[0066] The mixed gas and liquid flow into the bubble generation core unit 4 to generate initial micro-nano bubbles.

[0067] S3, average initial micro / nano bubble dispersion

[0068] The generated initial micro- and nano-bubbles then flow into the bubble homogenizer 5, where the helical motion of the helical blades 11 promotes the uniform dispersion and stable release of the bubbles, preventing the micro- and nano-bubbles from agglomerating.

[0069] S4, Formation of gas-liquid dispersion system

[0070] After being dispersed and averaged, the micro-nano bubbles flow into the water storage tank 10, forming a micro-nano bubble gas-liquid dispersion system.

[0071] S5, Ultrasonic Control

[0072] Ultrasonic waves are generated by an ultrasonic transducer 9 positioned above the gas-liquid interface of the water storage tank 10. Based on the Helmholtz resonance effect, primary bubbles are generated on the liquid surface under the action of the acoustic standing wave. By adjusting the distance between the ultrasonic transducer 9 and the liquid surface, the half-wavelength of the ultrasonic wave is adjusted to an integer multiple (such as λ / 2, λ, or 3λ / 2) to form a stable acoustic standing wave. For example, when the ultrasonic frequency is 100kHz, the wavelength λ is approximately 15mm, and the distance H can be adjusted to 7.5mm, 15mm, or 22.5mm, etc.

[0073] S6, Acoustic fracture refinement of particle size

[0074] Ultrasonic waves are generated by ultrasonic signal generator 7, and the generated primary bubbles are broken into smaller sub-bubbles through acoustic rupture mechanism. By adjusting the ultrasonic parameters and the distance between the ultrasonic generator probe 9 and the liquid surface, the particle size of micro-nano bubbles can be precisely controlled.

[0075] In step S6, the ultrasonic frequency range generated by the ultrasonic generating probe 9 is controlled to be from 65.26 kHz to 6.526 GHz, and the ultrasonic frequency is determined based on the Minnaert frequency formula for micro-nano bubbles.

[0076]

[0077] In the formula: R0 is the equilibrium radius of the micro / nano bubble, m; γ is the specific heat ratio of the gas inside the bubble, taken as 1.4 for air; P0 is the static pressure acting on the micro / nano bubble, Pa; ρ is the liquid density, kg / m³. 3 .

[0078] The sound-to-fracture refinement method is modulated by the position of micro / nano bubbles in the sound field:

[0079] Mode 1 (film outward folding): When the bubble is directly below the ultrasonic transducer (9), the bubble liquid film rapidly retracts towards the edge, folds outward under inertia, and breaks off, forming a ring-shaped sub-bubble string. This process is dominated by inertial effects, and the calculated Reynolds number (Re) is Re ~ 10. 3>>1 indicates that the inertial force is much greater than the viscous force, supporting the folding and pinching behavior of the liquid film. The Reynolds number expression is:

[0080]

[0081] In the formula: ρ is the liquid density, kg / m³ 3 R is the radius of the primary bubble, m; U is the recoil velocity of the liquid film, m / s; μ is the dynamic viscosity of the liquid, Pa·s;

[0082] Mode 2 (Thin Film Folding Inward): When the bubble deviates from the center of the ultrasonic transducer 9, it is attracted by the sound field, causing the liquid film to fold inward, enveloping the air and forming multiple small sub-bubbles. Acoustic radiation force dominates, and the calculated acoustic Bond number (Boa) is Bo. a >>1 indicates that the acoustic radiation force overcomes the surface tension, causing the bubble to become unstable and rupture. The expression for the acoustic Bond number is:

[0083]

[0084] In the formula: v rms σ is the root mean square value of the vibration velocity of the medium particles, in m / s; σ is the surface tension of the liquid, in N / m.

[0085] By adjusting ultrasonic parameters (such as frequency and sound pressure) and probe distance, precise control of particle size can be achieved. The refined micro / nano bubble particle size can be effectively reduced and the distribution more uniform.

[0086] This invention discloses a micro / nano bubble generator with controllable particle size. After operation, the operator can adjust the probe distance in real time via an electric telescopic platform 6 and monitor the sound field parameters using an ultrasonic signal generator 7, achieving automated control. Finally, the refined micro / nano bubbles are output from the outlet of the water storage tank 10 for use in environmental remediation, biomedicine, or industrial cleaning.

[0087] Figure 5-11 The bubble generation core unit 4 of this invention employs a dissolved gas release device corresponding to the pressure dissolved gas release method, a multi-stage depressurization and gas release structure corresponding to the hydraulic cavitation method, a Venturi tube corresponding to the hydraulic cavitation method, a vortex cavitation bubble breaker corresponding to the hydraulic cavitation method, an electrode plate corresponding to the electrolysis method, a microchannel device corresponding to the microchannel method, and an ultrasonic transducer corresponding to the ultrasonic cavitation method. Since these are all general-purpose components, their structural composition will not be described in detail.

[0088] The manufacturers and models of micro-nano bubble generators that are the core units for bubble generation (4) are listed in the table below: These include dissolved gas release devices or multi-stage depressurization and gas release structures for pressure dissolved gas release method, Venturi tubes or vortex cavitation bubble breakers for hydraulic cavitation method, electrode plates for electrolysis method, microfluidic chips or microchannel devices for microchannel method, and ultrasonic transducers for ultrasonic cavitation method.

[0089] serial number Methods used model factory 1 Pressure dissolved gas release method (dissolved gas release device) NZ-NMX200 Micro / Nano Bubble Generator Namei Innovation (Hangzhou) Technology Co., Ltd. 2 Multi-stage decompression and gas release structure Micro nano bubble generator 65EDQSL110S Shanghai Aidong Mechanical & Electrical Equipment Co., Ltd. 3 Hydraulic cavitation (Venturi tube) JXWNP Series Nano-Micro Bubble Generator Shanghai Zhongchen Digital Technology Equipment Co., Ltd. 4 Vortex cavitation bubble breaker Dyna Swirl® Bubble Generator Bafan Instruments & Equipment (Shanghai) Co., Ltd. 5 Electrode plates corresponding to electrolysis Wastewater treatment ozone micro-nano bubble generator Shanghai Zhongjing Environmental Protection Technology Co., Ltd. 6 Microchannel method corresponds to microfluidic chips or microchannel devices Microdroplet / Microsphere Preparation Apparatus - Droplet Microfluidic System (DG-01) Shanghai Pengzan Biotechnology Co., Ltd. 7 Ultrasonic transducer corresponding to ultrasonic cavitation method ZK-WNM Zhongke Sanyang Brand Nanobubble Generator Qingdao Zhongke Sanyang Purification Company

[0090] This invention generates initial micro / nano bubbles through an initial bubble generation component (primary bubble generation component), and then uses ultrasonic waves through a bubble refinement and dispersion component (secondary refinement component) to actively refine the bubble particle size by utilizing Helmholtz resonance and acoustic rupture mechanisms. This method is compatible with various existing bubble generators, has strong versatility, and is energy-efficient and pollution-free, significantly improving the application efficiency of micro / nano bubble technology.

[0091] The practical application results of this invention show that it effectively solves the problems of large average particle size and uncontrollable bubble size in existing micro-nano bubble generation methods. Through secondary ultrasonic refining, the particle size of micro-nano bubbles can be actively controlled, improving bubble uniformity and stability. Furthermore, this method can be combined with various existing generators such as pressure dissolved gas release, hydraulic cavitation, electrolysis, microchannel, and ultrasonic cavitation, demonstrating strong versatility and application flexibility.

[0092] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications and substitutions should all be covered within the scope of protection of the present invention.

Claims

1. A micro / nano bubble generator with controllable particle size, characterized in that: It includes an initial bubble generation component and a bubble refinement and dispersion component; The initial bubble generating assembly includes a gas cylinder (1), a liquid tank (2), a gas-liquid mixing valve (3), a bubble generating core unit (4), and a bubble homogenizer (5). The gas cylinder (1) and the liquid tank (2) are connected to the gas-liquid mixing valve (3) through connecting pipes. The gas-liquid mixing valve (3) is connected to the bubble generating core unit (4) through a gas-liquid conveying pipe. The bubble generating core unit (4) is connected to the bubble homogenizer (5) through a bubble conveying pipe. The bubble homogenizer (5) is equipped with a spiral blade (11). The bubble refining and dispersion assembly includes an electric telescopic platform (6), an ultrasonic signal generator (7), a signal amplifier (8), an ultrasonic generating probe (9), and a water tank (10) for accommodating the micro-nano bubble dispersion system. The electric telescopic platform (6) consists of two units, which are respectively installed on the top and bottom plates of the water tank (10). The ultrasonic generating probe (9) is vertically arranged above the gas-liquid interface of the water tank (10) via the electric telescopic platform (6) located on the top plate of the water tank (10). The ultrasonic signal generator (7) is connected to the ultrasonic generating probe (9) via the signal amplifier (8). The ultrasonic signal generator (7) generates a frequency range of 65.26kHz to 6.526GHz, and the signal amplifier (8) adjusts the sound pressure to 0.5MPa to 10MPa. The outlet of the bubble homogenizer (5) in the initial bubble generation component is connected to the inlet of the water tank (10) in the bubble refining and dispersing component via a pipeline.

2. The micro / nano bubble generator with controllable particle size as described in claim 1, characterized in that: The bubble generation core unit (4) is any one of the following: a dissolved gas release device corresponding to the pressure dissolved gas release method, a venturi tube corresponding to the hydraulic cavitation method, a vortex cavitation bubble breaker or a multi-stage decompression and gas release structure, an electrode plate corresponding to the electrolysis method, a microfluidic chip or microchannel device corresponding to the microchannel method, or an ultrasonic transducer corresponding to the ultrasonic cavitation method.

3. The micro / nano bubble generator with controllable particle size as described in claim 1, characterized in that: A pressure reducing valve and a flow meter are respectively installed on the connecting pipeline between the gas cylinder (1), the liquid tank (2) and the gas-liquid mixing valve (3) to control the flow rate of gas and liquid.

4. The micro / nano bubble generator with controllable particle size as described in claim 1, characterized in that: The electric telescopic platform (6) is equipped with a position feedback system, which can monitor and adjust the distance H between the ultrasonic generator probe (9) and the liquid surface in real time to ensure that H is an integer multiple of half the wavelength of the ultrasonic wave, so as to form a stable sound field standing wave.

5. A method for generating and controlling micro / nano bubbles with controllable particle size, characterized in that: The micro / nano bubble generator used includes an initial bubble generation component and a bubble refinement and dispersion component; The initial bubble generation assembly includes a gas cylinder (1), a liquid tank (2), a gas-liquid mixing valve (3), a bubble generation core unit (4), and a bubble homogenizer (5). The gas cylinder (1) and the liquid tank (2) are connected to the gas-liquid mixing valve (3) through connecting pipes. The gas-liquid mixing valve (3) is connected to the bubble generation core unit (4) through a gas-liquid delivery pipe. The bubble generation core unit (4) is connected to the bubble homogenizer (5) through a bubble delivery pipe. The bubble homogenizer (5) is equipped with a spiral blade (11). The bubble generation core unit (4) is any one of the following: a dissolved gas release device corresponding to the pressure dissolved gas release method, a venturi tube corresponding to the hydraulic cavitation method, a vortex cavitation bubble breaker or a multi-stage depressurization and gas release structure, an electrode plate corresponding to the electrolysis method, a microfluidic chip or microchannel device corresponding to the microchannel method, or an ultrasonic transducer corresponding to the ultrasonic cavitation method. The bubble refining and dispersion assembly includes an electric telescopic platform (6), an ultrasonic signal generator (7), a signal amplifier (8), an ultrasonic generating probe (9), and a water tank (10) for accommodating the micro-nano bubble dispersion system. The electric telescopic platform (6) consists of two units, which are respectively installed on the top and bottom plates of the water tank (10). The ultrasonic generating probe (9) is vertically arranged above the gas-liquid interface of the water tank (10) via the electric telescopic platform (6) located on the top plate of the water tank (10). The ultrasonic signal generator (7) is connected to the ultrasonic generating probe (9) via the signal amplifier (8). The outlet of the bubble homogenizer (5) in the initial bubble generation component is connected to the inlet of the water tank (10) of the bubble refining and dispersing component via a pipeline. The method for generating and controlling micro / nano bubbles includes the following steps: S1, gas-liquid mixture Gas and liquid are supplied by gas cylinder (1) and liquid tank (2) respectively, and are mixed in a set ratio through gas-liquid mixing valve (3) to form a mixed gas-liquid mixture; S2, Initial micro / nano bubble generation The mixed gas and liquid flow into the bubble generation core unit (4) to generate initial micro-nano bubbles; S3, average initial micro / nano bubble dispersion The generated initial micro-nano bubbles then flow into the bubble homogenizer (5), where the helical motion of the helical blades (11) promotes the uniform dispersion and stable release of the bubbles, thus preventing the micro-nano bubbles from agglomerating. S4, Formation of gas-liquid dispersion system After being dispersed and averaged, the micro-nano bubbles flow into the water storage tank (10) to form a micro-nano bubble gas-liquid dispersion system; S5, Ultrasonic Control Ultrasonic waves are generated by an ultrasonic wave generator (9) placed above the gas-liquid interface of the water tank (10). Based on the Helmholtz resonance effect, primary bubbles are generated on the liquid surface under the action of the sound field standing wave. The distance between the ultrasonic wave generator (9) and the liquid surface is adjusted to adjust the half wavelength of the ultrasonic wave to an integer multiple to form a stable sound field standing wave. S6, Acoustic fracture refinement of particle size Ultrasonic waves are generated by an ultrasonic signal generator (7), and the generated primary bubbles are broken into smaller sub-bubbles by an acoustic rupture mechanism. By adjusting the ultrasonic parameters and the distance between the ultrasonic generator probe (9) and the liquid surface, the particle size of micro-nano bubbles can be precisely controlled.

6. The method for generating and controlling micro / nano bubbles with controllable particle size as described in claim 5, characterized in that: In step S6, the ultrasonic frequency range generated by the ultrasonic generating probe (9) is controlled to be from 65.26 kHz to 6.526 GHz, and the ultrasonic frequency is determined based on the Minnaert frequency formula for micro-nano bubbles: In the formula: R0 is the equilibrium radius of the micro / nano bubble, m; γ is the specific heat ratio of the gas inside the bubble, taken as 1.4 for air; P0 is the static pressure acting on the micro / nano bubble, Pa; ρ is the liquid density, kg / m³. 3 .

7. The method for generating and controlling micro / nano bubbles with controllable particle size as described in claim 5, characterized in that: In step S6, the acoustic rupture mechanism is mode 1, where the film folds outward. When the micro-nano bubbles are directly below the ultrasonic transducer (9), the bubble liquid film rapidly retracts towards the edge, folds outward under inertial force, and breaks off, forming a ring-shaped sub-bubble string. This process is dominated by inertial effects, and the calculated Reynolds number (Re) is Re ~ 10. 3 >>1 indicates that the inertial force is much greater than the viscous force, supporting the folding and pinching behavior of the liquid film; the Reynolds number expression is: In the formula: ρ is the liquid density, kg / m³ 3 R is the radius of the primary bubble, in meters; U is the recoil velocity of the liquid film, in meters per second; μ is the dynamic viscosity of the liquid, in Pa·s.

8. The method for generating and controlling micro / nano bubbles with controllable particle size as described in claim 5, characterized in that: In step S6, the acoustic rupture mechanism is mode 2, where the film folds inward. When the bubble deviates from the probe center, the micro-nano bubbles are attracted by the acoustic field, causing the liquid film to fold inward and trap multiple small sub-bubbles. At this point, the acoustic radiation force dominates, and the calculated acoustic Bond number Boa is Bo. a >>1 indicates that the acoustic radiation force overcomes the surface tension; the expression for the acoustic Bond number is: In the formula: v rms σ is the root mean square value of the vibration velocity of the medium particles, in m / s; σ is the surface tension of the liquid, in N / m.

9. The method for generating and controlling micro / nano bubbles with controllable particle size as described in claim 5, characterized in that: In step S5, the half-wavelength of the ultrasound is adjusted to λ / 2, λ, or 3λ / 2 to optimize the standing wave of the sound field.

10. The method for generating and controlling micro / nano bubbles with controllable particle size as described in claim 5, characterized in that: Pressure reducing valves and flow meters are respectively installed on the connecting pipelines between the gas cylinder (1), liquid tank (2) and gas-liquid mixing valve (3) to control the flow rate of gas and liquid; the electric telescopic platform (6) is equipped with a position feedback system, which can monitor and adjust the distance H between the ultrasonic generator probe (9) and the liquid surface in real time to ensure that H is an integer multiple of half the wavelength of ultrasonic waves to form a stable sound field standing wave; the signal amplifier (8) adjusts the sound pressure to 0.5MPa~10MPa.

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