Superfine particulate matter efficient passing charging device and method with controllable charging efficiency

Abstract

The invention relates to an efficient passing charging device and method for ultrafine particles with controllable charging efficiency. The device comprises an inlet region, an ion vibration charge region and an outlet region. Four interlayers are arranged in the inlet area; and the inlet area is divided into a first sheath gas channel, a first sample gas channel, an ion channel, a second sample gas channel and a second sheath gas channel by the four interlayers. The ion vibration charge region comprises a charge cavity, a first metal electrode and a second metal electrode; the first metal electrode is an anode, and the second metal electrode is a cathode; alternating current is applied to the first metal electrode and the second metal electrode to form an alternating current electric field. The outlet area comprises a separation cavity, a third metal electrode and a fourth metal electrode; and a fixed electric field is formed between the third metal electrode and the fourth metal electrode. According to the invention, the charging speed can be controlled, the efficient charging of the ultrafine particles can be realized, and the charging efficiency of small-particle-size particles and the improvement of the single charging ratio of large-particle-size particles can be realized for different application scenes.

Description

Technical Field

[0001] The present invention relates to the technical field of charging of atmospheric ultrafine particles, and in particular to a highly efficient charging device and method for ultrafine particles with controllable charging efficiency. Background Art

[0002] Ultrafine particles in the atmosphere participate in complex atmospheric physical and chemical processes, which have a great impact on climate change and human health. Charging technology charges neutral ultrafine particles to obtain electrical mobility, which is the basis for studying the formation, diffusion, and transport mechanisms of atmospheric ultrafine particles. In the field of atmospheric ultrafine particle charging technology, unipolar or bipolar charging technology is often used to charge ultrafine particles.

[0003] The charging of ultrafine particles usually includes the following steps: (1) generating ions; (2) ion pretreatment; (3) collision and combination of ultrafine particles and ions. For example, a corona discharge diffusion charger uses high-voltage discharge to perform corona discharge on the ground to generate free ions, and then the free ions are drawn out of the discharge chamber through a clean airflow. The ultrafine particle sample gas flow and the free ion gas flow are then mixed. The particles and ions diffuse, collide, and combine in the mixed gas flow to eventually form charged particles. According to the particle diffusion charging theory proposed by Fuchs and Bricard, the charging speed of particles (which determines the charging probability distribution) is positively correlated with the degree of mixing, ion concentration, and particle size. That is, small-sized particles (≤23nm, the lower limit of the particle size of the National VI standard for motor vehicle emissions) have a low probability of charging, while large-sized particles have a high proportion of multiple charges.

[0004] At present, in the field of ultrafine particle detection, there is an urgent need for flexible adjustment of charging efficiency. For example, in the particle size distribution detection system of "charging-screening-measurement", for small-size particles (≤23nm), the ideal goal is to increase its charging efficiency as much as possible; while for large-size particles (>23nm), the ideal goal is to increase the single charge ratio as much as possible (suppress the multiple charge ratio). However, the existing technical methods are still unable to effectively control the charging efficiency. For example, in order to increase the degree of mixing to improve the charging efficiency, the Chinese patent document CN107101915A introduced a traction electric field, and the Chinese patent document CN107138277A designed a counterflow field. However, the uncontrollable degree of mixing makes it difficult for existing diffusion chargers to control the charging speed, that is, it is difficult to improve the charging efficiency by increasing the charging speed, or to reduce the charging speed to suppress multiple charging. In addition, increasing the degree of mixing will bring new problems, resulting in an increase in the loss of ultrafine particles and a decrease in the passing efficiency.

[0005] Therefore, existing diffusion chargers are difficult to meet the charging requirements of ultrafine particles, and it is necessary to design a charging device and method for ultrafine particles with controllable charging efficiency. Summary of the invention

[0006] The object of the present invention is to provide an ultrafine particle efficient charging device and method with controllable charging efficiency. The charging device can not only control the charging speed to achieve efficient charging of ultrafine particles, but also can improve the charging efficiency of small-size particles and the single charging ratio of large-size particles according to different application scenarios.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A highly efficient charging device for ultrafine particles with controllable charging efficiency comprises an inlet area, an ion vibration charging area and an outlet area which are arranged in sequence.

[0009] The inlet area adopts a first rectangular tube; four partitions are arranged in the first rectangular tube from top to bottom; the four partitions divide the inlet area into a first sheath gas channel, a first sample gas channel, an ion channel, a second sample gas channel and a second sheath gas channel.

[0010] The ion vibration charging zone includes a charging cavity and a first metal electrode and a second metal electrode respectively arranged on the top surface and the bottom surface inside the charging cavity; the first metal electrode is an anode and the second metal electrode is a cathode; alternating current is applied to the first metal electrode and the second metal electrode to form an alternating electric field between the two.

[0011] The outlet area includes a separation cavity and a third metal electrode and a fourth metal electrode arranged on the separation cavity; a fixed electric field is formed between the third metal electrode and the fourth metal electrode, and the direction of the fixed electric field is perpendicular to the direction of the alternating electric field.

[0012] Furthermore, the partition is realized by a metal sheet.

[0013] Furthermore, a discharge needle and a metal plate with a through hole are installed in the ion channel; and the area between the metal plate and the discharge needle base is the discharge area.

[0014] Furthermore, the discharge needle is installed in the ion channel through a discharge needle base; an air flow channel is opened through the discharge needle base.

[0015] Furthermore, the discharge needle and the through hole are both located on the center line of the ion channel; and the vertical distance between the tip of the discharge needle and the center of the through hole is 5 mm to 15 mm.

[0016] Furthermore, laminar flow devices are installed at the outlets of the first sheath gas channel and the second sheath gas channel; the laminar flow devices use a gauze with a mesh size greater than 300.

[0017] Furthermore, the charging cavity adopts a second rectangular tube, the second rectangular tube adopts a static dissipative insulating material, and the static dissipative insulating material adopts Saigang POM.

[0018] Furthermore, the first metal electrode is connected to the positive electrode of the analog signal generator, and the second metal electrode is connected to the negative electrode of the analog signal generator; an alternating electric field E1 is formed between the first metal electrode and the second metal electrode, and the frequency of the alternating electric field E1 is greater than 1kHz.

[0019] Furthermore, the separation cavity adopts a third rectangular tube, the third rectangular tube adopts a static dissipative insulating material, and the static dissipative insulating material adopts Saigang POM.

[0020] Furthermore, the gas flow rates in the first sheath gas channel, the first sample gas channel, the ion channel, the second sample gas channel and the second sheath gas channel are equal.

[0021] The present invention also includes a working method for the ultrafine particles with controllable charging efficiency to efficiently pass through the charging device, the method comprising the following steps:

[0022] S1. The tail end of the discharge needle is connected to a high voltage, the ion channel and the metal plate therein are connected to a high voltage reference ground, and the discharge needle performs corona discharge to the reference ground to generate a large number of free ions.

[0023] S2. Clean air is introduced into the first sheath gas channel and the second sheath gas channel respectively to form two sheath gas streams.

[0024] S3. Clean air is introduced into the air flow channel on the discharge needle base. The clean air enters the ion channel through the discharge area. The clean air entering the ion channel carries free ions to form a beam of ion airflow.

[0025] S4. Pass the sample gas containing ultrafine particles into the first sample gas channel and the second sample gas channel to form two sample gas flow streams.

[0026] S5, a total of five airflows, including one ion airflow, two sheath airflows and two sample airflows. After the five airflows enter the ion vibration charging zone, a laminar state of "sheath gas-sample gas-ion-sample gas-sheath gas" is formed, that is, the five airflows will maintain a stratified state; when there is no electric field force, the free ions and the ultrafine particles move along the airflow direction respectively and maintain a non-mixed state; the first metal electrode and the second metal electrode in the ion vibration charging zone are respectively connected to the positive and negative electrodes of the analog signal generator to form an AC electric field E1 between the two metal electrodes. Under the action of the AC electric field E1 and the airflow, the free ions in the ion airflow vibrate at high frequency in the ion airflow, sample airflow and sheath airflow, and collide with the ultrafine particles in the sample airflow to form charged ultrafine particles; the mixing degree of the free ions and the ultrafine particles is controlled by adjusting the frequency of the AC electric field E1, thereby controlling the charging efficiency.

[0027] S6. Connect the third metal electrode and the fourth metal electrode in the outlet area to different fixed voltages to form a fixed electric field E2 between the two metal electrodes; the direction of the fixed electric field is perpendicular to the directions of the AC electric field E1 and the flow field, and the free ions are deflected under the action of the fixed electric field E2 (assuming that the free ions are negative ions, which originally move along the direction of the total airflow, and under the action of the fixed electric field E2, they are deflected in the opposite direction of the fixed electric field E2), and are deposited on the metal electrodes in the outlet area, and the charged ultrafine particles pass through the fixed electric field E2 and leave the charging device with the total airflow.

[0028] Compared with the prior art, the advantages of the present invention are:

[0029] (1) The present invention not only realizes multiple intersections of the running trajectories of ultrafine particles and free ions through the design of the AC electric field in the ion vibration charging zone, causing high-frequency collisions between ultrafine particles and free ions, but also improves the mixing degree of ultrafine particles and free ions, solving the problem of "improving charging efficiency" in diffusion charging, thereby achieving high-efficiency charging of small-diameter ultrafine particles (less than 23 nm).

[0030] (2) The amplitude and frequency of the AC electric field in the ion vibration charging zone designed by the present invention can be adjusted according to demand. If the charged object is a small-diameter ultrafine particle (below 23nm), the amplitude and frequency of the AC electric field can be increased to improve the charging efficiency; if the charged object is a large-diameter ultrafine particle (above 23nm), the amplitude and frequency of the AC electric field can be reduced to increase the single charging ratio and suppress the probability of multiple charging. The ultrafine particle charger designed by the present invention realizes controllable charging efficiency.

[0031] (3) The present invention designs a flow field of a "sheath gas-sample gas-ion gas flow-sample gas-sheath gas" structure in the inlet area, and uses sheath gas flows on both sides to protect ultrafine particles in the sample gas flow and free ions in the ion gas flow, thereby reducing the loss of ultrafine particles and free ions and greatly improving the passing efficiency of ultrafine particles. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a structural schematic diagram of the ultrafine particles with controllable charging efficiency efficiently passing through the charging device in the present invention.

[0033] in:

[0034] 01. Entrance area, 02. Ion vibration charging area, 03. Exit area; 10-1. First sheath gas channel, 10-2. Second sheath gas channel, 11-1. First sample gas channel, 11-2. Second sample gas channel, 12. Discharge area, 13. Ion channel, 14. Metal plate with through holes, 15. Discharge needle base, 16. Discharge needle, 17. Clean air flow, 18. Sheath gas air flow, 19. Sample gas air flow; 20. Metal electrode (cathode), 21. Metal electrode (anode), 22. Ultrafine particle trajectory, 23. Free ion trajectory, 24. Electric field strength E1 (direction), 25. Electric field strength E1 (amplitude); 30. Electric field strength E2, 31. Total air flow. DETAILED DESCRIPTION

[0035] The present invention will be further described below in conjunction with the accompanying drawings:

[0036] like Figure 1 The charging device shown has a controllable charging efficiency and allows ultrafine particles to pass through efficiently. The device includes an inlet area 01, an ion vibration charging area 02 and an outlet area 03. The present invention can solve the deficiencies in the prior art and achieve controllable charging efficiency of the charging device and efficient passage of ultrafine particles.

[0037] The inlet area 01 is used to introduce the sheath gas, sample gas, and ion gas flow into the ion vibration charging area 02 in the structure of "sheath gas-sample gas-ion-sample gas-sheath gas". The sheath gas is used to protect the ultrafine particles in the sample gas to improve the passing efficiency. The inlet area 01 is a rectangular area, which is divided into two sheath gas channels 18, two sample gas channels 19, and one ion channel 13 in the structure of "sheath gas channel-sample gas channel-ion channel-sample gas channel-sheath gas channel", thereby realizing the laminar structure of "sheath gas-sample gas-ion-sample gas-sheath gas". This laminar structure has two advantages: on the one hand, the degree of mixing of the free ion beam and the particles can be controlled by the alternating current electric field, thereby adjusting the final charging probability; on the other hand, because the sheath gas is located on both sides of the laminar gas flow, it can protect the ultrafine particles and free ions, greatly reducing the loss of ultrafine particles and free ions, and improving the passing efficiency and the upper limit of the charging efficiency.

[0038] Furthermore, the inlet area 01 adopts a first rectangular tube; four partitions are arranged in the first rectangular tube from top to bottom; the four partitions divide the inlet area 01 into a first sheath gas channel, a first sample gas channel, an ion channel, a second sample gas channel and a second sheath gas channel. The partitions are implemented by metal sheets.

[0039] Furthermore, a discharge needle and a metal plate with a through hole are installed in the ion channel 13; the discharge needle 16 is installed in the ion channel 13 through a discharge needle base 15. The discharge needle 16 and the through hole are both located on the center line of the ion channel 13, and the vertical distance between the tip of the discharge needle 16 and the center of the through hole is 5 mm to 15 mm. The area between the metal plate 14 and the discharge needle base 15 is the discharge area 12.

[0040] Furthermore, the discharge needle base 15 is used to support and fix the discharge needle 16 and introduce a clean airflow 17. An airflow channel is provided through the discharge needle base 15, and the clean airflow 17 is introduced into the discharge area 12 through the airflow channel penetrating the discharge needle base 15. The clean airflow obtains free ions in the discharge area 12, and then carries the free ions through the ion channel 13 into the ion vibration charging area 02.

[0041] Furthermore, the sheath gas 18 is used to protect free ions and ultrafine particles. A laminar flow device is installed at the outlet of the sheath gas channel 10, and the laminar flow device uses a gauze with a mesh size greater than 300 meshes.

[0042] Furthermore, the gas flow rates of the two sheath gas channels, the two sample gas channels and the one ion channel are equal.

[0043] Preferably, the ion vibration charging zone 02 is used to provide an environment for ultrafine particles to collide with free ions. An AC electric field exists in the ion vibration charging zone, which causes the free ions to vibrate in a direction perpendicular to the flow field, intersecting with the sample gas flow (the sample gas flow contains ultrafine particles) at a certain frequency (>1kHz), and setting the frequency and amplitude of the AC electric field to control the collision probability of free particles and ultrafine particles, that is, to control the charging speed, and then control the charging efficiency.

[0044] Furthermore, the ion vibration charging zone 02 adopts a second rectangular tube, and the rectangular tube adopts an electrostatic dissipative insulating material, and the electrostatic dissipative insulating material adopts Saigang POM. The top and bottom of the inner side of the rectangular tube are respectively provided with a first metal electrode 21 and a second metal electrode 22, the first metal electrode 21 is an anode, and the second metal electrode 20 is a cathode. An electric field is formed between the first metal electrode 21 and the second metal electrode 20. In the ion vibration charging zone, the structure of "first metal electrode-sheath gas-sample gas-ion-sample gas-sheath gas-second metal electrode" is sequentially formed from top to bottom.

[0045] Furthermore, the metal electrodes in the ion vibration charged zone 02 are connected to an analog signal generator, wherein the second metal electrode 20 is connected to the negative electrode of the analog signal generator, and the first metal electrode 21 is connected to the positive electrode of the analog signal generator, and an alternating electric field E1 is formed between the first metal electrode and the second metal electrode, and the frequency of the alternating electric field E1 is greater than 1 kHz.

[0046] Furthermore, the ion vibration charged region 02 is a rectangular region, and an alternating electric field E1 exists in the rectangular region. The direction of E1 is as follows: Figure 1 As shown in the direction of arrow 24, the amplitude of E1 changes as follows Figure 1 As shown in the curve 25 in FIG. 1 , the integral of the amplitude of E1 over time is 0, so as to ensure that the displacement of the free ions in the direction of E1 can always pass through the sample gas flow, thereby making the free ions vibrate in the direction perpendicular to the flow field. The laminar structure of “sheath gas-sample gas-ion-sample gas-sheath gas” makes the motion trajectory of the free ions intersect with the sample gas on both sides for many times. The trajectory of the free ions is shown in FIG. Figure 1 As shown in curve 23 in FIG. , the trajectory of ultrafine particles in the sample gas is as follows Figure 1 As shown in curve 22 in , the collision between free ions and ultrafine particles is achieved and charging is completed.

[0047] According to the preferred embodiment of the present invention, a fixed electric field exists in the outlet area 03, which is used to remove excess free ions and lead out the total airflow 31 containing charged ultrafine particles. A fixed electric field E2 is perpendicular to the electric field E1 and the flow field in the outlet area, and the direction of the fixed electric field E2 is as follows: Figure 1 As shown in 30, Figure 1 The cross section shown is vertical and the electric field is used to remove excess free ions.

[0048] Furthermore, the outlet area 03 uses a third rectangular tube, which uses static dissipative insulating material, and the static dissipative insulating material uses Saigang POM. Two metal electrodes are embedded inside the rectangular tube to form a fixed electric field E2 (as shown in 30, perpendicular to E1 and the flow field).

[0049] The present invention also relates to a method for the above charging device, the method comprising the following steps:

[0050] S1. Connect the tail end of the discharge needle 16 to a high voltage, connect the ion channel 13 and the metal plate 14 therein to a high voltage reference ground, and the discharge needle 16 performs corona discharge on the reference ground to generate a large number of free ions.

[0051] S2. Pass clean air into two sheath gas channels 10 to form two bundles of sheath gas 18.

[0052] S3. Clean air 17 is passed from the discharge needle base 15 through the discharge area 12 into the ion channel 13. The clean air carries free ions to form a beam of ion airflow.

[0053] S4. Pass the sample gas containing ultrafine particles into two sample gas channels 11 to form two sample gas flow streams 19.

[0054] S5. After the five airflows enter the ion vibration charging zone 02, a laminar state of "sheath gas-sample gas-ions-sample gas-sheath gas" is formed, that is, the five airflows will maintain a stratified state. The laminar airflow stays in the ion vibration charging zone 02 for a short time, less than 1 second, and the five airflows will not mix with each other. When there is no electric field force (and diffusion is not considered), the free ions and ultrafine particles move along the airflow direction respectively, maintaining a non-mixed state. The two metal electrodes (20 and 21) in the ion vibration charging zone 02 are connected to an analog signal generator to form an alternating electric field E1, and the free ions in the ion airflow obtain a speed along the direction of the alternating electric field E1. Because the free ions have a speed along the direction of the ion airflow, the free ions vibrate at high frequency in the ion airflow, sample airflow, and sheath airflow (their motion trajectory is shown by the gray dotted arrow 23 in the figure), and collide with the ultrafine particles in the sample airflow (that is, the gray dotted arrow 23 in the figure intersects with the gray solid arrow 22), forming charged ultrafine particles. The free ion trajectory is Figure 1 As shown in curve 23 in Fig. Figure 1 As shown by the straight line 22 in FIG.

[0055] In this embodiment, the AC electric field E1 is a square wave, the frequency of the square wave is F, and the amplitude of the square wave is A. Assume that the sum of the widths of a single sheath gas channel and a single sample gas channel is W, and the average electrical mobility of free ions is Z p , then F and A must satisfy the following formula:

[0056] Z p A=2FW (1)

[0057] Assuming that the time for free ions to pass through the ion vibration charging zone 02 is t, and the probability of successful charging when the free ion beam collides with ultrafine particles in a single collision is P, then the formula for the degree of mixing of free ions and ultrafine particles is:

[0058] M=tF (2)

[0059] The total charging efficiency of the charging device is given by:

[0060] Q=1-(1-P) M (3)

[0061] From formula (1) to formula (3), it can be seen that by adjusting the frequency F of the AC electric field E1, the mixing degree of free ions and ultrafine particles can be controlled, and then the charging efficiency of the charging device can be controlled. When the frequency of the AC electric field E1 is high, the mixing degree of free ions and particles will also be high, and the final charging efficiency will also be high; when the frequency of the AC electric field E1 is low, the mixing degree of free ions and particles is low, the final charging efficiency is low, and the single charging ratio is high.

[0062] S6. Connect the two metal electrodes in the outlet area to a fixed voltage to form a fixed electric field E2 (perpendicular to E1 and the flow field). The free ions are deflected under the action of the fixed electric field E2. It is assumed that the free ions are negative ions, which originally move along the direction of the total airflow 31. Under the action of the fixed electric field E2, they are deflected in the opposite direction of the fixed electric field E2 and deposited on the metal electrodes in the outlet area. The charged ultrafine particles pass through the fixed electric field E2 due to their low electrical mobility and leave the charging device with the total airflow 31.

[0063] In summary, the present invention can solve the deficiencies in the prior art and achieve efficient charging of ultrafine particles with controllable charging efficiency.

[0064] The above-described embodiments are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the scope of protection determined by the claims of the present invention.

Claims

1. An ultrafine particle efficient charging device with controllable charging efficiency, characterized in that: The device comprises an inlet area (01), an ion vibration charging area (02) and an outlet area (03) which are arranged in sequence; The inlet area (01) adopts a first rectangular tube; four partitions are arranged in the first rectangular tube from top to bottom; the four partitions divide the inlet area (01) into a first sheath gas channel (10-1), a first sample gas channel (11-1), an ion channel (13), a second sample gas channel (11-2) and a second sheath gas channel (10-2); The ion vibration charging zone (02) comprises a charging cavity and a first metal electrode (21) and a second metal electrode (22) respectively arranged on the top surface and the bottom surface of the charging cavity; the first metal electrode (21) is an anode and the second metal electrode (20) is a cathode; alternating current is applied to the first metal electrode (21) and the second metal electrode (20) to form an alternating current electric field between the two; The outlet area (03) comprises a separation cavity and a third metal electrode and a fourth metal electrode arranged on the separation cavity; a fixed electric field is formed between the third metal electrode and the fourth metal electrode, and the direction of the fixed electric field is perpendicular to the direction of the alternating electric field.

2. The ultrafine particles with controllable charging efficiency according to claim 1 are characterized in that: The partition is realized by a metal sheet.

3. The ultrafine particles with controllable charging efficiency according to claim 1 are characterized in that: A discharge needle (16) and a metal plate (14) with a through hole are installed in the ion channel (13); the area between the metal plate (14) and the discharge needle base (15) is a discharge area (12); the discharge needle (16) is installed in the ion channel (13) through the discharge needle base (15); and an airflow channel is opened through the discharge needle base (15).

4. The ultrafine particles with controllable charging efficiency according to claim 1 are characterized in that: The discharge needle (16) and the through hole are both located on the center line of the ion channel (13); the vertical distance between the tip of the discharge needle (16) and the center of the through hole is 5 mm to 15 mm.

5. The ultrafine particles with controllable charging efficiency high-efficiency passing charging device according to claim 1, characterized in that: Laminar flow devices are installed at the outlets of the first sheath gas channel (10-1) and the second sheath gas channel (10-2); the laminar flow devices use a gauze with a mesh size greater than 300.

6. The ultrafine particle high-efficiency charging device with controllable charging efficiency according to claim 1, characterized in that: The charging cavity adopts a second rectangular tube, the second rectangular tube adopts a static dissipative insulating material, and the static dissipative insulating material adopts Saigang POM.

7. The ultrafine particle efficient charging device with controllable charging efficiency according to claim 1, characterized in that: The first metal electrode (21) is connected to the positive electrode of the analog signal generator, and the second metal electrode (20) is connected to the negative electrode of the analog signal generator; an alternating electric field E1 is formed between the first metal electrode (21) and the second metal electrode (20), and the frequency of the alternating electric field E1 is greater than 1 kHz.

8. The ultrafine particle high-efficiency charging device with controllable charging efficiency according to claim 1, characterized in that: The separation cavity adopts a third rectangular tube, the third rectangular tube adopts a static dissipative insulating material, and the static dissipative insulating material adopts Saigang POM.

9. The ultrafine particle efficient charging device with controllable charging efficiency according to claim 1, characterized in that: The gas flow rates in the first sheath gas channel (10-1), the first sample gas channel (11-1), the ion channel (13), the second sample gas channel (11-2) and the second sheath gas channel (10-2) are equal.

10. The working method for efficiently passing ultrafine particles through a charging device with controllable charging efficiency according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: S1, the tail end of the discharge needle (16) is connected to a high voltage, the ion channel (13) and the metal plate (14) therein are connected to a high voltage reference ground, and the discharge needle (16) performs corona discharge on the reference ground to generate free ions; S2, introducing clean air into the first sheath gas channel (10-1) and the second sheath gas channel (10-2) respectively to form two sheath gas streams (18); S3, clean air is introduced into the air flow channel on the discharge needle base (15), and the clean air is introduced into the ion channel (13) through the discharge area (12). The clean air entering the ion channel (13) carries free ions to form a beam of ion air flow; S4, passing the sample gas containing ultrafine particles into the first sample gas channel (11-1) and the second sample gas channel (11-2) to form two sample gas flow streams (19); S5, a total of five airflows, including one ion airflow, two sheath airflows and two sample airflows, form a laminar state of "sheath air-sample air-ion-sample air-sheath air" after the five airflows enter the ion vibration charging zone (02), that is, the five airflows will maintain a stratified state; when there is no electric field force, the free ions and the ultrafine particles move along the airflow direction respectively and maintain a non-mixed state; the first metal electrode (21) and the second metal electrode (10) in the ion vibration charging zone (02) are respectively connected to the positive electrode and the negative electrode of the analog signal generator, and an alternating electric field E1 is formed between the two metal electrodes. Under the action of the alternating electric field E1 and the airflow, the free ions in the ion airflow vibrate at a high frequency in the ion airflow, the sample airflow and the sheath airflow, and collide with the ultrafine particles in the sample airflow to form charged ultrafine particles; the mixing degree of the free ions and the ultrafine particles is controlled by adjusting the frequency of the alternating electric field E1, thereby controlling the charging efficiency; S6. Connect the third metal electrode and the fourth metal electrode in the outlet area (03) to different fixed voltages, so that a fixed electric field E2 is formed between the two metal electrodes; the direction of the fixed electric field is perpendicular to the directions of the AC electric field E1 and the flow field, and the free ions are deflected under the action of the fixed electric field E2 and deposited on the metal electrodes in the outlet area, and the charged ultrafine particles pass through the fixed electric field E2 and leave the charging device with the total airflow (31).

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