Monodisperse aerosol sorting device and method based on alternating electric field and ultrasound

Abstract

The application provides a monodisperse aerosol screening device and method based on alternating electric field and ultrasonic effect, and relates to the technical field of particle screening. The device comprises a device body, wherein a charging area, a first screening area and a second screening area are sequentially arranged inside the device body along the aerosol flow direction. A thorn electrode ring is arranged near the aerosol inlet end of the charging area. Four first electrode rods are symmetrically arranged around the central axis of the first screening area. Four second electrode rods are symmetrically arranged around the central axis of the second screening area. At least one ultrasonic sound source is arranged on the side surface of the first screening area and the second screening area. A plurality of dust collection plates are arranged inside the first screening area and the second screening area for capturing free charged particles. The application effectively combines alternating electric field and sound field technology, designs layered particle charging and screening areas, and achieves the purposes of high-efficiency particle screening, high-precision particle size screening, low loss of target particle size particles and simple programmable particle screening system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of particle screening, in particular to a monodisperse aerosol screening device and method based on alternating electric field and ultrasonic effect. BACKGROUND

[0002] At present, with the rapid development of various industries, the traditional particle size screening device has problems such as insufficient screening precision, low processing efficiency, easy clogging and low automation, which can no longer meet the increasing demand for fine, efficient and intelligent particle screening in various industries. At the same time, with the rapid development of emerging fields such as nanotechnology, pharmaceuticals, chemicals, food and others, higher requirements are put forward for accurate control and efficient screening of particle size. The traditional screening device is difficult to achieve accurate classification when facing ultra-fine particles, irregularly shaped particles and sticky particles. The rapid development of intelligent technology provides technical support for the upgrading of screening devices, enabling the equipment to realize remote monitoring, automatic adjustment and fault diagnosis, and further improving the intelligent level of production and quality control capability. Therefore, from the perspective of industry development demand, environmental protection requirements and intelligent trend, it is of great significance and urgency to develop innovative new particle size screening devices.

[0003] Among the methods commonly used to combine different technologies with particle screening devices, such as aerodynamics, electromagnetism, acoustics and optics, designing more efficient particle screening devices by combining these technologies has become the preferred choice to improve particle screening efficiency and precision. The aerodynamic particle sizer of Cambond Company in the United States uses the principle that the centrifugal force on particles in a centrifugal field is proportional to the mass of the particles, and the mass is proportional to the cube of the particle size, so that aerosol particles move in the centrifugal field, and particles of different sizes experience different centrifugal forces, thereby achieving separation. The Model 3080 / 3081 / 3082 DMA of TSI Company in the United States uses a columnar structure, with the outer sleeve grounded and the center pole connected to a positive pressure generator. By changing the voltage of the center pole, charged particles of different sizes can be screened. By effectively combining acoustics and microfluidic chips, particles of different properties and sizes in the chip experience different acoustic forces and acoustic radiation forces in the liquid, thereby achieving particle screening. The NanoWizard series AFM optical tweezer system developed by JPK Instruments Company in Germany uses a highly focused laser beam to generate a three-dimensional optical field potential well to capture, manipulate and measure micro particles. When the particle size matches the optical field distribution of the optical tweezer, the optical tweezer can accurately capture and manipulate the particles, thereby achieving separation of particles of different sizes.

[0004] In the design of efficient particle screening device, either new technical means is developed or the device structure is optimized on the original technical means. In the existing technical means, through the effective combination of electromagnetism and particle screening device, good screening efficiency, screening precision and stability are shown, which is a kind of particle screening technology that is currently popular. However, when the particles are screened by the electric field itself, the particles need to be pre-charged, and the charging efficiency and the accuracy of the charge will affect the subsequent particle motion trajectory, and then affect the screening efficiency and precision of the particles. In addition, when the charged particles move in the electric field, the accurate prediction of the motion trajectory of different size particles is a key link to screen the target particles, and it is necessary to ensure that the charged particles do not collide and agglomerate as much as possible, and the particles adhere to the wall and pipeline, thereby causing excessive loss of target particle size particles. The adhesion of too many particles to the electrode rod will reduce the potential energy emitted by the electrode rod, and the space charge effect caused by the long discharge time of the electrode rod itself will distort the electric field emitted by the electrode rod, which will affect the particle motion trajectory and reduce the particle screening precision. After a series of processes, the traditional method of combining electromagnetism and particle screening device has a high degree of complexity, which leads to low particle screening efficiency, low screening precision and excessive loss of target particles in the pipeline, which is a problem that needs to be solved urgently. To some extent, the above problems limit the wide application of the method of combining electromagnetism and particle screening device and system. In summary, the main shortcomings of the traditional method of combining electromagnetism and particle screening device are: 1. Low particle screening efficiency; 2. Low particle screening precision; 3. Excessive loss of target particle size particles; 4. Complex particle screening device and method.

[0005] In summary, it is very necessary to design a monodisperse aerosol screening device and method based on alternating electric field and ultrasonic action. SUMMARY

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

[0007] To achieve the above purpose, the present application provides the following solutions:

[0008] The application provides a monodisperse aerosol screening device based on alternating electric field and ultrasonic effect, which comprises a device body, a power supply unit, an acoustic signal unit and a central controller, wherein the device body is internally sequentially provided with a charging area, a primary screening area and a secondary screening area along the aerosol flow direction; the charging area is provided with a thorn electrode ring near the aerosol inlet end for receiving high-voltage direct current and corona charging the polydisperse aerosol particles passing through; four first electrode rods are symmetrically arranged around the central axis of the primary screening area; four second electrode rods are symmetrically arranged around the central axis of the secondary screening area for receiving alternating current signals and forming time-varying alternating electric fields in the respective areas to screen particles with different ranges of charge-to-mass ratio; at least one ultrasonic sound source is arranged on the side of the primary screening area and the secondary screening area for emitting ultrasonic waves to remove particles adhering to the electrode rods in the corresponding area; and a plurality of dust collection plates are arranged in the primary screening area and the secondary screening area for capturing free charged particles.

[0009] The power supply unit is connected to the central controller for providing alternating current signals.

[0010] The acoustic signal unit is connected to the central controller for providing amplified acoustic signals.

[0011] The central controller is connected to the thorn electrode ring, the ultrasonic sound source and the electrode rods, and the ground end of the central controller is connected to the dust collection plate.

[0012] Preferably, the device body is arranged in a vertical manner.

[0013] Preferably, the power supply unit comprises a high-voltage direct current power supply and an alternating current power supply, wherein the high-voltage direct current power supply and the alternating current power supply are connected to the central controller, the high-voltage direct current power supply is used to provide high-voltage positive direct current or high-voltage negative direct current, and the alternating current power supply is used to provide alternating current signals.

[0014] Preferably, the acoustic signal unit comprises a signal generator and a power amplifier, wherein the signal generator is connected to the power amplifier, and the power amplifier is connected to the central controller.

[0015] Preferably, the first electrode rods and the second electrode rods are symmetrically arranged, four first electrode rods are simultaneously connected to the positive and negative poles of the first alternating current output end of the central controller, and four second electrode rods are simultaneously connected to the positive and negative poles of the second alternating current output end of the central controller, so as to provide alternating current signals to the four rod electrodes in the two areas to generate time-varying alternating electric fields inside, control the movement of particles with different charge-to-mass ratios, and achieve the purpose of particle screening; and the arrangement density of the second electrode rods is greater than that of the first electrode rods.

[0016] Preferably, the dust collection plates are arranged parallel to the ultrasonic sound sources.

[0017] Preferably, the ultrasonic sound source is two, respectively arranged in the side center position of the first and second screening zone.

[0018] Preferably, the dust collection plate is four, respectively arranged in the opposite side of the first and second screening zone.

[0019] The application also provides a monodisperse aerosol screening method based on alternating electric field and ultrasonic effect, applied to the monodisperse aerosol screening device based on alternating electric field and ultrasonic effect, comprising:

[0020] The central controller controls the high-voltage direct current applied by the thorn electrode ring to corona charge the polydisperse aerosol particles entering the charging area, so that the particles carry the same charge;

[0021] 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, so that the particles meeting the first specific charge-to-mass ratio make directional suspension motion near the axis and pass through the area, and the remaining particles are screened out;

[0022] The central controller controls the four second electrode rods in the second screening zone to apply an alternating current signal to form a second time-varying alternating electric field, so that the particles meeting the second specific charge-to-mass ratio make directional suspension motion near the axis and pass through the area to output, and the remaining particles are screened out, wherein 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.

[0023] During the screening process, the central controller controls the ultrasonic sound source to intermittently emit ultrasonic waves to remove particles attached to the electrode rods;

[0024] At the same time during the screening process, the grounded dust collection plate captures the charged particles in the screening zone to suppress the distortion of the electric field caused by the space charge effect.

[0025] Preferably, the electric field density of the second time-varying alternating electric field is greater than that of the first time-varying alternating electric field.

[0026] According to the specific embodiments provided by the application, the following technical effects are disclosed:

[0027] The application provides a monodisperse aerosol screening device and method based on alternating electric field and ultrasonic effect, which comprises a device body, a power supply unit, an acoustic wave signal unit and a central controller, wherein the device body is internally sequentially provided with a charging area, a first screening area and a second screening area along the aerosol flow direction, the charging area is provided with a thorn electrode ring close to the aerosol inlet end for receiving high-voltage direct current and corona charging the polydisperse aerosol particles passing therethrough, four first electrode rods are symmetrically arranged around the central axis of the first screening area, four second electrode rods are symmetrically arranged around the central axis of the second screening area for receiving alternating current signals and forming time-varying alternating electric fields in the respective areas to screen particles with different ranges of charge-to-mass ratio, at least one ultrasonic sound source is arranged on the side of the first screening area and the second screening area for emitting ultrasonic waves to remove particles adhering to the electrode rods in the corresponding area, and a plurality of dust collection plates are arranged in the first screening area and the second screening area for capturing free charged particles.

[0028] 1. The application firstly realizes the continuity of particle pre-charging and screening through the continuous integration design of the three areas in the device, and ensures that the target particles always keep directional and contactless suspension motion near the axis through the time-varying alternating electric field, the output signals are all controlled by the central controller, the long-term stable screening of single particle size particles and the continuous screening of different particle sizes in different time periods can be realized, and the screening efficiency of the device is greatly improved.

[0029] 2. The particles are also pre-charged, but the application forms a time-varying alternating electric field in the interior by connecting alternating current signals to the eight electrode rods, so that the particles with a specific charge-to-mass ratio always keep directional and contactless suspension motion near the axis, and the particles that do not meet the specific charge-to-mass ratio are bounced out of the potential well, thereby improving the screening precision, and the particles adhering to the electrode rods are effectively removed through the synergistic effect of the dust collection plate and the ultrasonic wave, the electric field distortion caused by the space charge efficiency is reduced, and the screening precision of the particles is greatly improved.

[0030] 3. The application realizes the pre-charging and screening of particles in the same device through the integrated design of the three-area particle screening device, and ensures that the target particle size particles always keep directional motion near the axis in the device through the time-varying alternating electric field, thereby greatly reducing the adhesion of particles to the pipeline and wall surface, the collision and agglomeration probability of particles, and the excessive loss of target particle size particles.

[0031] 4、The application is easy to clean and simple to assemble and disassemble, and the central controller can realize the simple operation of the particle screening through the centralized programmable control of the output end. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description only constitute some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0033] Figure 1 It is a structural schematic diagram of the device of the present application.

[0034] Figure 2a It is a front view of the particle screening device.

[0035] Figure 2b It is a right view of the particle screening device.

[0036] Figure 3 It is an overall explosion diagram of the device horizontally placed.

[0037] Figure 4 It is a whole signal circuit diagram of the device.

[0038] Reference signs: 1, charged area; 2, first screening area; 3, second screening area; 4, thorn electrode ring; 5, first electrode rod; 6, second electrode rod; 7, ultrasonic sound source; 8, central controller; 9, high-voltage direct-current power supply; 10, alternating-current power supply; 11, power amplifier; 12, signal generator; 13, dust collecting plate. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments only constitute some embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0040] The purpose of the present application is to provide a monodisperse aerosol screening device and method based on alternating electric field and ultrasonic action. Through the effective combination of alternating electric field and sound field technology, a layered particle charging screening area is designed to achieve high-efficiency and high-precision particle size screening, low loss of target particle size particles, and a simple programmable particle screening system.

[0041] In order to make the above objectives, characteristics and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0042] First, the following terms need to be introduced:

[0043] 1. Time-varying alternating electric field: Under the access of alternating current signal, the potential on the electrode rod will change sinusoidally at a certain frequency, so that an electric field varying with time is generated in the inner region of the four electrode rods;

[0044] 2. Space charge effect: Due to the continuous positive and negative discharge of the time-varying alternating electric field to the surrounding air, positive and negative ions are generated by ionization of air, and under the continuous accumulation of positive and negative ions, an electric charge region with certain spatial distribution is formed.

[0045] As shown in Figure 1 , Figure 2a , Figure 2b , Figure 3 and Figure 4 , the present application provides a monodisperse aerosol screening device based on alternating electric field and ultrasonic effect, comprising: a device body, a power supply unit, an acoustic signal unit and a central controller 8, the device body is provided with a charging area 1, a primary screening area 2 and a secondary screening area 3 in sequence along the aerosol flow direction inside the device body, the charging area 1 is provided with a thorn electrode ring 4 near the aerosol inlet end, which is used to receive high-voltage direct current and carry out corona charging on the polydisperse aerosol particles passing through it, four first electrode rods 5 are symmetrically arranged around the central axis of the primary screening area 2, four second electrode rods 6 are symmetrically arranged around the central axis of the secondary screening area 3, which are used to receive alternating current signals and form time-varying alternating electric field in the respective areas to screen particles with different charge-to-mass ratios, at least one ultrasonic sound source 7 is arranged on the side of the primary screening area 2 and the secondary screening area 3, which is used to emit ultrasonic waves to remove particles adhering to the electrode rods in the corresponding area, a plurality of dust collection plates 13 are arranged inside the primary screening area 2 and the secondary screening area 3, which are used to capture free charged particles;

[0046] The power supply unit is connected to the central controller 8 for providing AC and DC signals;

[0047] The acoustic signal unit is connected to the central controller 8 for providing amplified acoustic units;

[0048] The central controller 8 is connected with the thorn electrode ring 4, the ultrasonic sound source 7 and the electrode stick, and the ground end of the central controller 8 is connected with the dust collecting plate 13, and the detailed description is as follows: the input end of the central controller 8 is connected with the high-voltage direct-current power supply 9, the power amplifier 11 and the alternating-current power supply 10 respectively, for receiving the direct-current signal, the alternating-current signal and the ultrasonic signal provided by each instrument, the output end of the central controller 8 is connected with the thorn electrode ring 4, the electrode stick and the ultrasonic sound source 7 respectively, for outputting the corresponding signal after adjustment to the corresponding device, and the ground end of the central controller 8 is connected with the dust collecting plate 13, so that the dust collecting plate 13 is grounded, and through the terminal regulation and control of the central controller 8, the output signals of each instrument can be concentrated and regulated, so that the long-time screening of the single-particle-size particles and the effective screening of the particles with different particle sizes in different time periods are realized.

[0049] The thorn electrode ring 4 is arranged near the aerosol inlet end of the device charging area 1, for receiving the high-voltage positive direct current or the high-voltage negative direct current sent by the central controller 8, so that the particles passing through the thorn electrode ring 4 are corona charged, and the thorn electrode ring 4 has stronger electrode ring surface tip discharge performance than the ordinary electrode ring, so that the particle charging efficiency is improved.

[0050] As shown in Figure 3 The device body is arranged vertically and is composed of four parts, and the detachable device structure can be disassembled at any time to remove the accumulated particles in the interior due to long-time operation, so that the device structure is simple and convenient to disassemble and clean.

[0051] The power supply unit includes the high-voltage direct-current power supply 9 and the alternating-current power supply 10, the high-voltage direct-current power supply 9 and the alternating-current power supply 10 are connected with the central controller 8, the high-voltage direct-current power supply 9 is used for providing high-voltage positive direct current or high-voltage negative direct current, and the alternating-current power supply 10 is used for providing alternating-current signals.

[0052] The sound wave signal unit includes the signal generator 12 and the power amplifier 11, the signal generator 12 is connected with the power amplifier 11, for providing the sound wave signal including the sound wave intensity and the sound wave frequency, and the power amplifier 11 is connected with the central controller 8, for amplifying the sound wave signal provided by the signal generator 12 to the ultrasonic range and transmitting the sound wave signal to the central controller 8.

[0053] As shown in Figure 4As shown in the figure, three cross sections in the device are shown, which are the cross section of the charged area 1, the cross section of the lateral thorn electrode ring 4 and the cross section of the electrode rod and dust collecting plate 13 in the first screening area 2 and the second screening area 3, respectively. The thorn electrode ring 4 is connected to the positive or negative output end of the central controller 8 to provide high-voltage positive direct current or high-voltage positive direct current to the thorn electrode ring 4 for pre-charging particles. The first electrode rod 5 and the second electrode rod 6 are symmetrically arranged, and the four first electrode rods 5 are connected to the positive and negative output ends of the first alternating current output end of the central controller 8, and the four second electrode rods 6 are connected to the positive and negative output ends of the second alternating current output end of the central controller 8 to provide alternating current to the four rod electrodes in the two areas to generate a time-varying alternating electric field inside to control the movement of particles with different mass-to-charge ratios to achieve the purpose of particle screening. The arrangement density of the second electrode rod 6 is greater than that of the first electrode rod 5, so that the charged particles are more significantly affected by the electric field force caused by the change of position, and particles with a particle size close to the target particle size can be screened out, thereby improving the screening precision.

[0054] As shown in Figure 2a and Figure 2b As shown in the figure, the general structure of the particle screening device from different angles and the specific arrangement position of the internal dust collecting plate and the ultrasonic sound source can be seen. The dust collecting plate 13 is arranged parallel to the ultrasonic sound source 7.

[0055] The ultrasonic sound source 7 is two, which are arranged at the center of the side of the first screening area 2 and the second screening area 3, respectively, for receiving the ultrasonic signal emitted by the central controller 8, and converting the ultrasonic signal into ultrasonic wave form to emit it out, so as to remove the particles attached to the four electrode rods in the first and second screening areas 3. The ultrasonic wave emitted by the ultrasonic sound source 7 has stronger energy than the ordinary sound source, and has no noise pollution.

[0056] The dust collecting plate 13 is four, which is arranged in the opposite side of the first screening area 2 and the second screening area 3, respectively, and is connected to the ground end of the central controller 8, for capturing the charged particles in the first and second screening areas 3, and reducing the electric field distortion caused by space charge effect in the first and second screening areas 3, thereby improving the screening precision of the particles. Through the effective combination of the grounded dust collecting plate 13 and the ultrasonic sound source 7, the decrease of the electric field strength caused by the particles attached to the electrode rods is significantly reduced, and the precision of the particle screening is improved.

[0057] The application also provides a monodisperse aerosol screening method based on alternating electric field and ultrasonic action, which is applied to the monodisperse aerosol screening device based on alternating electric field and ultrasonic action.

[0058] The high-voltage direct current is applied to the thorn electrode ring 4 under the control of the central controller 8, and the polydisperse aerosol particles entering the charged area 1 are corona charged to carry the same charge;

[0059] The four first electrode rods 5 in the first screening area 2 are controlled by the central controller 8 to apply an alternating current signal to form a first time-varying alternating electric field, so that the particles satisfying the first specific charge-to-mass ratio make directional suspended motion near the axis and pass through the area, and the remaining particles are screened out.

[0060] The four second electrode rods 6 in the second screening area 3 are controlled by the central controller 8 to apply an alternating current signal to form a second time-varying alternating electric field, so that the particles satisfying the second specific charge-to-mass ratio make directional suspended motion near the axis and pass through the area to be output, and the remaining particles are screened out, wherein the second specific charge-to-mass ratio corresponds to a different particle size range from 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.

[0061] During the screening process, the central controller 8 controls the ultrasonic sound source 7 to intermittently emit ultrasonic waves to remove the particles attached to the electrode rods.

[0062] At the same time during the screening process, the grounded dust collection plate 13 captures the charged particles in the screening area to suppress the distortion of the electric field caused by the space charge effect.

[0063] 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 action time sequence of each signal, so as to realize long-time stable screening of a single particle size or continuous screening of different particle sizes in different time periods.

[0064] The electric field density of the second time-varying alternating electric field is greater than that of the first time-varying alternating electric field.

[0065] In the description, each embodiment is described in a progressive manner, and each embodiment focuses on the difference from other embodiments. The same or similar parts between each embodiment can be referred to each other.

[0066] The principles and implementation modes of the present application are described by applying specific examples. The above description of the embodiments is only used to help understand the method and core idea of the present application; meanwhile, for those skilled in the art, the specific implementation mode and application range can be changed according to the idea of the present application. In conclusion, the content of the description should not be understood as a limitation of the present application.

Claims

1. A monodisperse aerosol sizing device based on the effect of alternating electric field and ultrasound, characterized in that, The device comprises a device body, a power supply unit, an acoustic signal unit and a central controller. The device body is internally provided with a charging area, a primary screening area and a secondary screening area in sequence along the aerosol flow direction. The charging area is provided with a thorn electrode ring near the aerosol inlet end for receiving high-voltage direct current and corona charging the polydisperse aerosol particles passing through. Four first electrode rods are symmetrically arranged around the central axis of the primary screening area. Four second electrode rods are symmetrically arranged around the central axis of the secondary screening area for receiving alternating current signals and forming time-varying alternating electric fields in the respective areas to screen particles with different ranges of charge-to-mass ratio. At least one ultrasonic sound source is arranged on the side of the primary screening area and the secondary screening area for emitting ultrasonic waves to remove particles adhering to the electrode rods in the corresponding area. A plurality of dust collection plates are arranged inside the primary screening area and the secondary screening area for capturing free charged particles. The power supply unit is connected to the central controller for providing alternating current signals. The acoustic signal unit is connected to the central controller for providing amplified acoustic signals. The central controller is connected to the thorn electrode ring, the ultrasonic sound source and the electrode rods. The ground end of the central controller is connected to the dust collection plate. The device body is arranged in a vertical manner.

2. The apparatus of claim 1, wherein, The power supply unit comprises a high-voltage direct current power supply and an alternating current power supply. The high-voltage direct current power supply and the alternating current power supply are connected to the central controller. The high-voltage direct current power supply is used to provide high-voltage positive direct current or high-voltage negative direct current. The alternating current power supply is used to provide alternating current signals.

3. The apparatus of claim 2, wherein, The acoustic signal unit comprises a signal generator and a power amplifier. The signal generator is connected to the power amplifier. The power amplifier is connected to the central controller.

4. The apparatus of claim 3, wherein, The first electrode rods and the second electrode rods are symmetrically arranged. Four first electrode rods are simultaneously connected to the positive and negative poles of the first alternating current output end of the central controller. Four second electrode rods are simultaneously connected to the positive and negative poles of the second alternating current output end of the central controller. The four rod electrodes in the two areas are provided with alternating current signals to generate time-varying alternating electric fields inside to control the movement of particles with different charge-to-mass ratios, achieving the purpose of particle screening. The arrangement density of the second electrode rods is greater than that of the first electrode rods.

5. The apparatus of claim 4, wherein, The dust collection plates are arranged parallel to the ultrasonic sound sources.

6. The apparatus of claim 5, wherein, There are two ultrasonic sound sources, which are arranged at the center positions of the sides of the primary screening area and the secondary screening area.

7. The apparatus of claim 6, wherein, There are four dust collection plates, which are arranged on opposite sides of the primary screening area and the secondary screening area in an externally extendable manner.

8. The apparatus of claim 7, wherein, The central controller controls the thorn electrode ring to apply high-voltage direct current to corona charge the polydisperse aerosol particles entering the charging area, so that the particles carry the same charge.

9. A method for sizing monodisperse aerosol based on the effect of alternating electric field and ultrasound, applied to the device for sizing monodisperse aerosol based on the effect of alternating electric field and ultrasound according to any one of claims 1-8, characterized in that, The central controller controls the four first electrode rods in the primary screening area to apply alternating current signals to form a first time-varying alternating electric field, so that the particles meeting a first specific charge-to-mass ratio make directional suspension motion near the axis and pass through the area, and the remaining particles are screened out. ​ ​ The four second electrode rods in the secondary screening zone are controlled by the central controller to apply an alternating current signal to form a second time-varying alternating electric field, so that the particles with a second specific charge-to-mass ratio make directional suspended motion near the axis and are output through the region, and the remaining particles are screened out, wherein the second specific charge-to-mass ratio corresponds to a different particle size range from 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 controls the ultrasonic sound source to intermittently emit ultrasonic waves to remove particles attached to the electrode rods. At the same time, during the screening process, the grounded dust collection plate captures the charged particles in the screening zone and suppresses the distortion of the electric field caused by space charge effect.

10. The method of claim 9, wherein, 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.

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