Monodisperse aerosol screening device and method based on alternating electric field and ultrasonic action

Abstract

The invention provides a monodisperse aerosol screening device and method based on an alternating electric field and ultrasonic action, and relates to the technical field of particle screening, the device comprises a device body, and a charge region, a primary screening region and a secondary screening region are sequentially arranged in the device body in the aerosol flowing direction; a barb electrode ring is arranged at the position, close to the aerosol inlet end, of the charge area, four first electrode bars are symmetrically arranged around the center axis of the first-stage screening area, four second electrode bars are symmetrically arranged around the center axis of the second-stage screening area, and at least one ultrasonic sound source is arranged on the side face of each of the first-stage screening area and the second-stage screening area. A plurality of dust collecting plates are arranged in the first-stage screening area and the second-stage screening area and used for capturing free charged particles. By effectively combining the alternating electric field and the sound field technology, a layered particle charge screening area is designed, and the purposes of high particle screening efficiency, high-precision particle size screening, low loss of particles with target particle sizes and a simple programmable particle screening system are achieved.

Description

Technical Field

[0001] This invention relates to the field of particle sieving technology, and in particular to a device and method for sieving monodisperse aerosols based on alternating electric field and ultrasonic action. Background Technology

[0002] Currently, with the rapid development of various industries, traditional particle size screening devices suffer from problems such as insufficient screening accuracy, low processing efficiency, easy clogging, and low automation, making it difficult to meet the growing demands of various industries for finer, more efficient, and intelligent particle screening. Simultaneously, the rapid development of emerging fields such as nanotechnology, pharmaceuticals, chemicals, and food has placed higher demands on the precise control of particle size and efficient screening. Traditional screening devices struggle to achieve accurate classification when dealing with ultrafine particles, irregularly shaped particles, and sticky particles. Furthermore, increasingly stringent environmental policies and the deepening of the concept of sustainable development require improvements in screening equipment in areas such as reducing energy consumption, minimizing waste emissions, and increasing resource recycling rates. The rapid development of intelligent technologies provides technical support for upgrading screening devices, enabling them to achieve functions such as remote monitoring, automatic adjustment, and fault diagnosis, further enhancing the level of intelligent production and quality control capabilities. Therefore, from the perspectives of industry development needs, environmental requirements, and the trend towards intelligentization, developing innovative new particle size screening devices is of great significance and urgency.

[0003] Among the commonly used methods of combining different technologies with particle sieving devices, such as aerodynamics, electromagnetics, acoustics, and optics, designing more efficient particle sieving devices by combining these technologies has become the preferred approach to improving particle sieving efficiency and accuracy. The aerodynamic particle size analyzer from Cambond Corporation in the United States utilizes the principle that the centrifugal force on a particle in a centrifugal field is proportional to its mass, and mass is proportional to the cube of its diameter. This allows aerosol particles to move in a centrifugal field, with particles of different sizes experiencing different centrifugal forces, thus achieving separation. The Model 3080 / 3081 / 3082 DMA from TSI Corporation in the United States employs a cylindrical structure with a grounded outer sleeve and a central electrode connected to a positive voltage generator. By changing the voltage of the central electrode, charged particles of different sizes are sieving. By effectively combining acoustics and microfluidic chips, the different acoustic migration forces and acoustic radiation forces experienced by particles of different properties and sizes in a liquid are utilized, thereby achieving particle sieving. The NanoWizard series of AFM optical tweezers systems launched by German company JPK Instruments utilizes a three-dimensional optical field potential trap generated by a highly focused laser beam to capture, manipulate, and measure microscopic particles. When the particle size matches the optical field distribution of the optical tweezers, the optical tweezers can precisely capture and manipulate the particles, thereby achieving the separation of particles of different sizes.

[0004] When designing efficient particle screening devices, either new technologies must be developed or the device structure must be optimized based on existing technologies. Among existing technologies, the effective combination of electromagnetics and particle screening devices exhibits good screening efficiency, accuracy, and stability, making it a popular particle screening technology. However, because particles must be pre-charged when screening using an electric field, the charging efficiency and accuracy of the charge will affect the subsequent particle trajectory, thus impacting screening efficiency and accuracy. Furthermore, accurately predicting the trajectory of charged particles of different sizes in the electric field is crucial for screening the target particles. During screening, it is essential to prevent collisions and agglomeration between charged particles and adhesion to walls and pipes, which can lead to excessive loss of target particle sizes. Excessive particle adhesion to the electrode rod reduces the potential energy emitted by the electrode rod, and the prolonged discharge time of the electrode rod itself causes space charge effects around it, distorting the electric field emitted by the electrode rod. Both of these factors affect particle trajectory, leading to reduced particle screening accuracy. The series of processes involved in traditional methods combining electromagnetics with particle screening devices results in high complexity, leading to low screening efficiency, low screening accuracy, and excessive loss of target particles in the pipeline – a problem that urgently needs to be addressed. These issues, to some extent, limit the widespread application of methods combining electromagnetics with particle screening devices and systems. In summary, the main drawbacks of traditional electromagnetics-particle screening technology are: 1. Low particle screening efficiency; 2. Low particle screening accuracy; 3. Excessive loss of target particle sizes; 4. Complex particle screening devices and methods.

[0005] In summary, it is essential to design a monodisperse aerosol sieving device and method based on alternating electric field and ultrasonic action. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, the purpose of this invention is to provide a monodisperse aerosol sieving device and method based on alternating electric field and ultrasonic action.

[0007] To achieve the above objectives, the present invention provides the following solution: This invention provides a monodisperse aerosol sieving device based on alternating electric field and ultrasonic action, comprising: a device body, a power supply unit, an acoustic signal unit, and a central controller. The device body contains a charging zone, a primary sieving zone, and a secondary sieving zone arranged sequentially along the aerosol flow direction. The charging zone has a barbed electrode ring near the aerosol inlet end for receiving high-voltage direct current and corona-charging the passing polydisperse aerosol particles. Four first electrode rods are symmetrically arranged around the central axis of the primary sieving zone, and four second electrode rods are symmetrically arranged around the central axis of the secondary sieving zone for receiving alternating current signals and forming a time-varying alternating electric field within their respective areas to sieve particles with different charge-to-mass ratios. At least one ultrasonic source is provided on the side of each primary and secondary sieving zone to emit ultrasonic waves to remove particles attached to the electrode rods in the corresponding areas. Multiple dust collection plates are arranged inside each primary and secondary sieving zone to capture free charged particles. The power supply unit is connected to the central controller and is used to provide AC and DC signals; The acoustic signal unit is connected to the central controller and is used to provide amplified acoustic signals. The central controller is connected to the barbed electrode ring, the ultrasonic source, and the electrode rod, and the grounding terminal of the central controller is connected to the dust collection plate.

[0008] Preferably, the device body is arranged vertically.

[0009] Preferably, the power supply unit includes a high-voltage DC power supply and an AC power supply, which are connected to the central controller. The high-voltage DC power supply is used to provide high-voltage positive DC power or high-voltage negative DC power, and the AC power supply is used to provide AC signals.

[0010] Preferably, the acoustic signal unit includes a signal generator and a power amplifier, the signal generator being connected to the power amplifier, and the power amplifier being connected to the central controller. Preferably, the first electrode rods and the second electrode rods are arranged symmetrically. The four first electrode rods are simultaneously connected to the positive and negative terminals of the first AC output terminal of the central controller, and the four second electrode rods are simultaneously connected to the positive and negative terminals of the second AC output terminal of the central controller. This is used to provide AC signals to the four rod electrodes in the two regions, so that they generate a time-varying alternating electric field inside, controlling the movement of particles with different charge-to-mass ratios, and achieving the purpose of particle sieving. The arrangement density of the second electrode rods is greater than that of the first electrode rods.

[0011] Preferably, the dust collection plate is arranged parallel to the ultrasonic sound source.

[0012] Preferably, there are two ultrasonic sound sources, which are respectively arranged at the center of the side of the primary screening zone and the secondary screening zone.

[0013] Preferably, there are four dust collection plates, which can be externally arranged on the opposite side of the primary screening zone and the secondary screening zone.

[0014] This invention also provides a method for sieving monodisperse aerosols based on alternating electric fields and ultrasonic effects, applied to the aforementioned monodisperse aerosol sieving device based on alternating electric fields and ultrasonic effects, comprising: The central controller controls the application of high-voltage direct current to the barbed electrode ring, which corona-charges the polydisperse aerosol particles that are introduced into the charging region, so that the particles carry the same charge. The central controller controls the four first electrode rods in the first screening zone to apply an alternating current signal to form a first time-varying alternating electric field, which causes particles that meet the first specific charge-to-mass ratio to make directional suspension motion near the axis and pass through the area, while the remaining particles are screened out. The central controller controls the four second electrode rods in the secondary screening zone to apply an alternating current signal to form a second time-varying alternating electric field, which causes particles that meet the second specific charge-to-mass ratio to directionally suspend near the axis and be output through the area, while the remaining particles are screened out. The second specific charge-to-mass ratio corresponds to a different particle size range than the first specific charge-to-mass ratio, and the particle size range corresponding to the second specific charge-to-mass ratio is narrower and belongs to the particle size range corresponding to the first specific charge-to-mass ratio. During the screening process, the ultrasonic source is controlled by the central controller to intermittently emit ultrasonic waves to remove particles attached to the electrode rod. Meanwhile, during the screening process, grounded dust collection plates capture free charged particles within the screening area, suppressing electric field distortion caused by space charge effect.

[0015] Preferably, the electric field density of the second time-varying alternating electric field is greater than the electric field density of the first time-varying alternating electric field.

[0016] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects: This invention provides a sieving device and method for monodisperse aerosols based on alternating electric fields and ultrasonic effects. The device includes a main body, a power supply unit, an acoustic signal unit, and a central controller. Inside the main body, along the aerosol flow direction, are sequentially arranged a charging zone, a primary sieving zone, and a secondary sieving zone. A barbed electrode ring is positioned near the aerosol inlet in the charging zone to receive high-voltage direct current and corona charge the passing polydisperse aerosol particles. Four first electrode rods are symmetrically arranged around the central axis of the primary sieving zone, and four second electrode rods are symmetrically arranged around the central axis of the secondary sieving zone. These receive alternating current signals and form a time-varying alternating electric field within their respective zones to sieve particles with different charge-to-mass ratios. At least one ultrasonic source is positioned on the side of each primary and secondary sieving zone to emit ultrasonic waves to remove particles attached to the electrode rods in the corresponding zones. Multiple dust collection plates are installed inside each primary and secondary sieving zone to capture free charged particles. This invention has the following advantages: 1. This invention firstly uses a continuous integrated design of three regions inside the device to ensure the continuity of particle pre-charging and screening through a time-varying alternating electric field. The target particles always remain near the axis and perform a suspended, non-contact directional movement. All output signals are controlled by a central controller, which can realize long-term stable screening of single-size particles and continuous screening of different particle sizes in different time periods, greatly improving the screening efficiency of the device. 2. While both methods involve pre-charging the particles, this invention differs from traditional methods that use direct current to deflect particle movement. Instead, it uses alternating current signals connected to eight electrode rods to create a time-varying alternating electric field within them. This ensures that particles meeting a specific charge-to-mass ratio remain near the axis, maintaining a directional, non-contact suspended motion, while particles not meeting the specific charge-to-mass ratio are ejected from the potential well. This improves screening accuracy. Furthermore, the combined effect of the dust collection plate and ultrasound effectively removes particles attached to the electrode rods, reducing electric field distortion caused by space charge efficiency and significantly enhancing particle screening accuracy. 3. The present invention integrates the design of a three-zone particle screening device, which enables the pre-charging and screening of particles to be achieved within the same device. Furthermore, through a time-varying alternating electric field, the target particle size particles are always kept in directional motion near the axis inside the device, which greatly reduces the adhesion of particles to pipes and walls, the probability of particle collision and agglomeration, and reduces excessive loss of target particle size particles. 4. This invention features an integrated design of a three-zone particle screening device, an externally insertable dust collection plate, and a detachable design of the four parts of the device, making it easy to clean and simple to assemble and disassemble. The central controller provides centralized programmable control of the output end, enabling simple operation of particle screening. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the device structure of the present invention; Figure 2a Front view of the particle screening device Figure 2b This is a right view of the particle screening device; Figure 3 This is an exploded view of the device when it is placed horizontally. Figure 4 This is the overall signal circuit diagram of the device.

[0019] Reference numerals: 1. Charged area; 2. Primary sieve zone; 3. Secondary sieve zone; 4. Spiked electrode ring; 5. First electrode rod; 6. Second electrode rod; 7. Ultrasonic sound source; 8. Central controller; 9. High voltage DC power supply; 10. AC power supply; 11. Power amplifier; 12. Signal generator; 13. Dust collection plate. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] The purpose of this invention is to provide a monodisperse aerosol sieving device and method based on alternating electric field and ultrasonic action. By effectively combining alternating electric field and acoustic field technology, a layered particle charging sieving region is designed to achieve high particle sieving efficiency, high-precision particle size sieving, low loss of target particle size, and a simple programmable particle sieving system.

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] First, we need to introduce some terminology: 1. Time-varying alternating electric field: When an alternating current signal is applied, the electric potential on the electrode rod will change sinusoidally at a certain frequency, causing it to generate a time-varying electric field in the internal region of the four electrode rods. 2. Space charge effect: Due to the continuous positive and negative discharges of the alternating electric field that changes over time, the air is ionized to produce positive and negative ions. With the continuous accumulation of positive and negative ions, a charge region with a certain spatial distribution is formed.

[0024] like Figure 1 , Figure 2a , Figure 2b , Figure 3 and Figure 4 As shown, this invention provides a monodisperse aerosol sieving device based on alternating electric field and ultrasonic action, comprising: a device body, a power supply unit, an acoustic signal unit, and a central controller 8. The device body contains a charging zone 1, a primary sieving zone 2, and a secondary sieving zone 3 arranged sequentially along the aerosol flow direction. The charging zone 1 has a barbed electrode ring 4 near the aerosol inlet end for receiving high-voltage direct current and corona-charging the polydisperse aerosol particles passing through it. Four first electrode rods 5 are symmetrically arranged around the central axis of the primary sieving zone 2, and four second electrode rods 6 are symmetrically arranged around the central axis of the secondary sieving zone 3 for receiving alternating current signals and forming a time-varying alternating electric field within their respective areas to sieve particles with different charge-to-mass ratios. At least one ultrasonic source 7 is provided on the side of each of the primary sieving zone 2 and the secondary sieving zone 3 for emitting ultrasonic waves to remove particles attached to the electrode rods in the corresponding areas. Multiple dust collection plates 13 are arranged inside the primary sieving zone 2 and the secondary sieving zone 3 to capture free charged particles. The power supply unit is connected to the central controller 8 and is used to provide AC and DC signals; The acoustic signal unit is connected to the central controller 8 and is used to provide amplified acoustic signals. The central controller 8 is connected to the spiked electrode ring 4, the ultrasonic source 7, and the electrode rod. The grounding terminal of the central controller 8 is connected to the dust collection plate 13. Specifically, the input terminals of the central controller 8 are connected to the high-voltage DC power supply 9, the power amplifier 11, and the AC power supply 10, respectively, to receive DC signals, AC signals, and ultrasonic signals provided by each instrument. The output terminals of the central controller 8 are connected to the spiked electrode ring 4, the electrode rod, and the ultrasonic source 7, respectively, to output the corresponding calibrated signals to the corresponding devices. The grounding terminal of the central controller 8 is connected to the dust collection plate 13, grounding the dust collection plate 13. Through the terminal control function of the central controller 8, the output signals of each instrument can be centrally and programmably controlled, achieving long-term sieving of particles of a single diameter and effective sieving of particles of different diameters within different time periods. The spiked electrode ring 4 is arranged in the charging area 1 of the device near the aerosol inlet end. It is used to receive high-voltage positive DC or high-voltage negative DC from the central controller 8, so that the particles passing through the spiked electrode ring 4 are corona charged. Compared with ordinary electrode rings, the spiked electrode ring 4 has stronger discharge performance at the tip of the electrode ring surface, thereby improving the particle charging efficiency.

[0025] like Figure 3 As shown, the device body is arranged vertically and consists of four parts. Its detachable structure allows it to be disassembled at any time to remove the particles accumulated inside due to long-term operation. The device has a simple structure and is easy to disassemble and clean.

[0026] The power supply unit includes a high-voltage DC power supply 9 and an AC power supply 10. The high-voltage DC power supply 9 and the AC power supply 10 are connected to the central controller 8. The high-voltage DC power supply 9 is used to provide high-voltage positive DC power or high-voltage negative DC power, and the AC power supply 10 is used to provide AC signals.

[0027] The acoustic signal unit includes a signal generator 12 and a power amplifier 11. The signal generator 12 is connected to the power amplifier 11 and is used to provide acoustic signals, including acoustic intensity and acoustic frequency. The power amplifier 11 is connected to the central controller 8 and is used to amplify the acoustic signals provided by the signal generator 12 to the ultrasonic range and transmit them to the central controller 8.

[0028] like Figure 4 As shown in the figure, three cross-sections of the device are captured: the cross-section of the transverse barbed electrode ring 4 in the charging zone 1, the transverse cross-section of the electrode rod and dust collection plate 13 in the first-stage sieve zone 2, and the transverse cross-section of the electrode rod and dust collection plate 13 in the second-stage sieve zone 3. The barbed electrode ring 4 is connected to the positive or negative terminal of the DC output of the central controller 8, providing high-voltage positive DC current to the barbed electrode ring 4 for pre-charging the particles. The first electrode rod 5 and the second electrode rod 6 are arranged symmetrically, and all four first electrode rods 5 are simultaneously connected to the first AC output of the central controller 8. The positive and negative terminals of the output end, and the four second electrode rods 6 are simultaneously connected to the positive and negative terminals of the second AC output terminal of the central controller 8 to provide AC power to the four rod electrodes in the two areas, so that they generate a time-varying alternating electric field inside, controlling the movement of particles with different charge-to-mass ratios, and achieving the purpose of particle sieving; the arrangement density of the second electrode rods 6 is greater than that of the first electrode rods 5, so that the electric field force on the charged particles due to the change of position is more significant, and particles with similar target particle size can be sieved, thus improving the sieving accuracy.

[0029] like Figure 2a and Figure 2bAs shown in the figure, the general structure of the particle screening device from different perspectives can be seen, as well as the specific arrangement of the internal dust collection plate and the ultrasonic source. The dust collection plate 13 is arranged parallel to the ultrasonic source 7.

[0030] Two ultrasonic sound sources 7 are respectively arranged at the center of the side of the primary sieve section 2 and the secondary sieve section 3. They are used to receive ultrasonic signals emitted by the central controller 8 and to convert the ultrasonic signals into ultrasonic waves and emit them to remove particles attached to the four electrode rods in the primary and secondary sieve sections 3. Compared with ordinary sound sources, the ultrasonic waves emitted by the ultrasonic sound sources 7 have stronger energy and no noise pollution.

[0031] The dust collection plates 13 consist of four pieces, which can be externally arranged on the opposite sides of the primary screening section 2 and the secondary screening section 3, and connected to the grounding terminal of the central controller 8. They are used to capture free charged particles in the primary and secondary screening sections 3, and reduce the electric field distortion caused by the space charge effect in the primary and secondary screening sections 3, thereby improving the particle screening accuracy. Through the effective combination of the grounded dust collection plates 13 and the ultrasonic source 7, the decrease in electric field strength caused by particles attached to the electrode rod is significantly reduced, thereby improving the particle screening accuracy.

[0032] This invention also provides a method for sieving monodisperse aerosols based on alternating electric fields and ultrasonic effects, applied to the aforementioned monodisperse aerosol sieving device based on alternating electric fields and ultrasonic effects, comprising: The central controller 8 controls the barbed electrode ring 4 to apply high voltage DC current to corona charge the polydisperse aerosol particles introduced into the charging region 1, so that the particles carry the same charge. The central controller 8 controls the four first electrode rods 5 in the first screening zone 2 to apply an alternating current signal to form a first time-varying alternating electric field, so that particles that meet the first specific charge-to-mass ratio can make directional suspension motion near the axis and pass through the area, while the remaining particles are screened out. The central controller 8 controls the four second electrode rods 6 in the secondary screening zone 3 to apply an alternating electric signal to form a second time-varying alternating electric field, so that the particles that meet the second specific charge-to-mass ratio can make directional suspension motion near the axis and be output through the area, while the remaining particles are screened out. The second specific charge-to-mass ratio corresponds to a different particle size range than the first specific charge-to-mass ratio, and the particle size range corresponding to the second specific charge-to-mass ratio is narrower and belongs to the particle size range corresponding to the first specific charge-to-mass ratio. During the screening process, the central controller 8 controls the ultrasonic source 7 to intermittently emit ultrasonic waves to remove particles attached to the electrode rod. Meanwhile, during the screening process, the grounded dust collection plate 13 captures free charged particles in the screening area, suppressing electric field distortion caused by the space charge effect.

[0033] The central controller 8 can programmably control the polarity of the high-voltage direct current, the voltage and frequency of the alternating current signal, the intensity and frequency of the ultrasonic signal, and the timing of each signal, so as to achieve long-term stable sieving of particles of a single size or continuous sieving of particles of different sizes within different time periods.

[0034] The electric field density of the second time-varying alternating electric field is greater than that of the first time-varying alternating electric field.

[0035] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0036] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A monodisperse aerosol sieving device based on alternating electric field and ultrasonic action, characterized in that, include: The device comprises a main body, a power supply unit, an acoustic signal unit, and a central controller. Inside the main body, along the aerosol flow direction, are sequentially arranged a charging zone, a primary sieving zone, and a secondary sieving zone. The charging zone has a barbed electrode ring near the aerosol inlet to receive high-voltage direct current and corona charge the passing polydisperse aerosol particles. Four first electrode rods are symmetrically arranged around the central axis of the primary sieving zone, and four second electrode rods are symmetrically arranged around the central axis of the secondary sieving zone to receive alternating current signals and form a time-varying alternating electric field within their respective areas to sieve particles with different charge-to-mass ratios. At least one ultrasonic source is located on the side of each primary and secondary sieving zone to emit ultrasonic waves to remove particles attached to the electrode rods in the corresponding areas. Multiple dust collection plates are installed inside each primary and secondary sieving zone to capture free charged particles. The power supply unit is connected to the central controller and is used to provide AC and DC signals; The acoustic signal unit is connected to the central controller and is used to provide amplified acoustic signals. The central controller is connected to the barbed electrode ring, the ultrasonic source, and the electrode rod, and the grounding terminal of the central controller is connected to the dust collection plate.

2. The apparatus according to claim 1, characterized in that, The device body is arranged vertically.

3. The apparatus according to claim 2, characterized in that, The power supply unit includes a high-voltage DC power supply and an AC power supply. The high-voltage DC power supply and the AC power supply are connected to the central controller. The high-voltage DC power supply is used to provide high-voltage positive DC power or high-voltage negative DC power, and the AC power supply is used to provide AC signals.

4. The apparatus according to claim 3, characterized in that, The acoustic signal unit includes a signal generator and a power amplifier. The signal generator is connected to the power amplifier, and the power amplifier is connected to the central controller.

5. The apparatus according to claim 4, characterized in that, The first and second electrode rods are arranged symmetrically. The four first electrode rods are simultaneously connected to the positive and negative terminals of the first AC output terminal of the central controller, and the four second electrode rods are simultaneously connected to the positive and negative terminals of the second AC output terminal of the central controller. This is used to provide AC signals to the four rod electrodes in the two regions, so that they generate a time-varying alternating electric field inside, controlling the movement of particles with different charge-to-mass ratios, and achieving the purpose of particle sieving. The arrangement density of the second electrode rods is greater than that of the first electrode rods.

6. The apparatus according to claim 5, characterized in that, The dust collection plate is arranged parallel to the ultrasonic sound source.

7. The apparatus according to claim 6, characterized in that, There are two ultrasonic sound sources, which are respectively arranged at the center of the side of the primary sieve section and the secondary sieve section.

8. The apparatus according to claim 7, characterized in that, The dust collection plates consist of four pieces, which can be externally arranged on the opposite sides of the primary screening zone and the secondary screening zone.

9. A method for sieving monodisperse aerosols based on alternating electric field and ultrasonic action, applied to the monodisperse aerosol sieving device based on alternating electric field and ultrasonic action as described in any one of claims 1-8, characterized in that, include: The central controller controls the application of high-voltage direct current to the barbed electrode ring, which corona-charges the polydisperse aerosol particles that are introduced into the charging region, so that the particles carry the same charge. The central controller controls the four first electrode rods in the first screening zone to apply an alternating current signal to form a first time-varying alternating electric field, which causes particles that meet the first specific charge-to-mass ratio to make directional suspension motion near the axis and pass through the area, while the remaining particles are screened out. The central controller controls the four second electrode rods in the secondary screening zone to apply an alternating current signal to form a second time-varying alternating electric field, which causes particles that meet the second specific charge-to-mass ratio to directionally suspend near the axis and be output through the area, while the remaining particles are screened out. The second specific charge-to-mass ratio corresponds to a different particle size range than the first specific charge-to-mass ratio, and the particle size range corresponding to the second specific charge-to-mass ratio is narrower and belongs to the particle size range corresponding to the first specific charge-to-mass ratio. During the screening process, the ultrasonic source is controlled by the central controller to intermittently emit ultrasonic waves to remove particles attached to the electrode rod. Meanwhile, during the screening process, grounded dust collection plates capture free charged particles in the screening area and suppress electric field distortion caused by space charge effect.

10. The method according to claim 9, characterized in that, The electric field density of the second time-varying alternating electric field is greater than that of the first time-varying alternating electric field.

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