Particle size distinguishing nano-particle collection device and method

Abstract

The invention discloses a particle size distinguishing nano particulate matter collecting device and method, and belongs to the technical field of atmospheric particulate matter collection. A collection cavity is formed in a collector main body of the collection device, a cold polar plate is arranged at the top of the collection cavity, a hot polar plate is arranged at the bottom of the collection cavity, the collection cavity is provided with an air inlet communicated with the atmosphere, and an outlet of the collection cavity is connected with an air pump; the two film supporting tables are both arranged at the bottom end of the film supporting frame, a collecting hole penetrating from the top of the collector body to the interior of the collecting cavity is formed in the collector body, a protection cavity is further formed in the collector body, and the film supporting frame driving part is used for enabling the two film supporting tables in the collecting hole and the protection cavity to complete position exchange. According to the invention, collection of nanoscale particles can be realized, the sampling efficiency is high, and the particle size range of the collected particles is wide.

Description

Technical Field

[0001] The present invention relates to the technical field of atmospheric particle collection, and in particular to a particle size-resolved nanoparticle collection device and method. Background Art

[0002] Fine atmospheric particulate matter has a significant impact on human health, air quality, and climate change. The environmental impact of particulate matter is closely related to its particle size. For example, nanoparticles have the characteristics of small particle size and high concentration, and are more likely to penetrate deep into the alveoli through the respiratory system, which may have a more serious impact on human health. In order to accurately assess the potential health risks of nanoparticles and understand their physical and chemical properties, it is very important to collect particles by particle size. Single particle analysis is an important technical means to characterize the characteristics of particles, and single particle analysis technology based on microscopy plays a key role in it. In order to carry out such analysis, it is a crucial prerequisite to collect single particles of different particle sizes from complex environments. Traditional single particle collection devices mostly use the inertial impact method. Since large-size particles have a large inertia, they can be collected by impact, while nano-size particles have a small inertia and will flow away with the airflow, making it difficult to rely on the inertial impact method to collect them. Therefore, the existing single particle collection devices cannot collect nano-size particles. Summary of the invention

[0003] The purpose of the present invention is to overcome the problems in the prior art and provide a nano-particle collection device and method with particle size resolution, which can realize the collection of nano-particles.

[0004] The present invention provides a nano-particle collection device with particle size resolution, comprising a collector, a collector body, a cold electrode plate and a hot electrode plate, wherein a collection chamber is arranged in the collector body, the cold electrode plate is arranged at the top of the collection chamber, the hot electrode plate is arranged at the bottom of the collection chamber, the collection chamber has an air inlet connected to the atmosphere, and the outlet of the collection chamber is connected to an air pump; during collection, the nano-particle collection device with particle size resolution of the present invention utilizes the interaction between gas molecules and particles to generate a certain thermophoresis velocity from the hot electrode plate to the cold electrode plate The particles move forward with the gas and also move toward the cold electrode plate, and finally hit the cold electrode plate.

[0005] The collector includes a film support frame, two film support stages and a film support frame driving unit. The two film support stages are both arranged at the bottom of the film support frame. The film support stages are used to carry sample films, and the sample films are located at the bottom of the film support stages. The collector body is provided with a collection hole that runs from the top of the collector body to the inside of the collection cavity. The collector body is also provided with a protective cavity. The two film support stages are respectively located in the collection hole and the protective cavity. The film support frame driving unit is used to enable the two film support stages in the collection hole and the protective cavity to complete the position exchange. The sample films on the two film support stages can be used to collect nanoparticles alternately, and the sample films collected with nanoparticles can be directly used for subsequent detection and analysis.

[0006] Preferably, at least one semiconductor refrigeration sheet is arranged in the film supporting table, a film supporting plate made of the same material as the cold electrode plate is arranged at the bottom of the film supporting table, the sample film is located at the bottom of the film supporting plate, the semiconductor refrigeration sheet is used to provide cold air to the film supporting plate, and a radiator is arranged on the film supporting table for dissipating heat and cooling the semiconductor refrigeration sheet.

[0007] Preferably, the film support frame driving unit comprises: The transmission shaft comprises a vertically arranged fixed shaft, a movable shaft and a first steering gear; the top of the fixed shaft is fixedly connected to the first steering gear, the bottom of the fixed shaft is provided with a square hole along the axial direction, the top of the movable shaft is a square shaft head, the square shaft head is located in the square hole, and a compression spring is provided between the square shaft head and the square hole, and the film support frame is connected to the bottom end of the movable shaft; The lever comprises a collar, a connecting rod and a rolling part, wherein the rolling part and the collar are respectively located at two ends of the connecting rod, the collar is sleeved on the movable shaft, and one side of the collar is fixed by a shaft shoulder, and the other side is fixed by a retaining spring; The cam assembly comprises a cam and a second servo for driving the cam to rotate. The outer surface of the cam is provided with a cam groove, and a rolling part is embedded in the cam groove. The rolling part can roll along the cam groove when the cam rotates.

[0008] Preferably, temperature sensors are provided on both the cold pole plate and the hot pole plate.

[0009] Preferably, a regulating valve for regulating the intake air flow rate is installed at the air inlet of the air pump.

[0010] Preferably, a sealing ring is provided on the outer periphery of the film supporting platform or the inner wall of the collecting hole and the protective cavity.

[0011] The present invention also provides a collection method using the above-mentioned nanoparticle collection device for particle size resolution, comprising the following steps: When the particle size of the particles to be collected is When , the thermophoresis velocity of nanoparticles is: , where λ is the mean free path of gas molecules; T is the ambient temperature, T is the temperature gradient, is the viscosity of the gas, is the gas density; When the particle size of the particles to be collected is When , the thermophoresis velocity of nanoparticles is: ; where H is the coefficient, is the correction factor; When the distance between the cold plate and the hot plate is determined, a gap is created between the cold plate and the hot plate. Temperature gradient in °C / mm, The value range is 1~ 2. When When the time of entering the collection cavity is calculated The maximum thermophoretic velocity of nanoparticles ,according to , to find out the shortest time for nanoparticles to hit the cold plate , where a is the distance between the two plates; when the nanoparticles entering the collection chamber have a speed of The shortest distance that particles move horizontally between the cold plate and the hot plate at a certain time , at the shortest distance Set the first sample membrane to collect the particle size of particulate matter; For particle size The particles will hit the sample membrane behind the first sample membrane, realizing the collection of particles of different sizes.

[0012] Preferably, the correction factor : ,in , , , is the particle size of the particles.

[0013] Preferably, the coefficient H is defined as: ,in is the thermal conductivity of the particles, is the thermal conductivity of the surrounding gas, is the particle size of the particles.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: a particle size-resolved nanoparticle collection device proposed by the present invention includes a collector and a collector, and by designing a cold electrode plate and a hot electrode plate arranged up and down in the collector body, the particles following the gas into the cold electrode plate and the hot electrode plate can obtain a thermophoresis velocity, and at the same time, the difference in thermophoresis velocity of nanoparticles of different particle sizes is utilized to realize the collection of nano-scale particles of different particle size ranges. The present invention also directly places the sample film at a determined position of the cold electrode plate through the designed collector, and realizes the replacement and protection of the sample film through the cooperation of the film support frame and the film support frame driving part, thereby improving the sampling efficiency, and the collected nanoparticles are directly collected on the sample film and can be directly used for subsequent detection and analysis.

[0015] The particle size-resolved nanoparticle collection device proposed in the present invention has significant advantages over traditional atmospheric particle collection devices. It can effectively and synchronously collect atmospheric nanoparticles of different particle sizes within a certain range, thus providing a new technical means for studying and evaluating the impact of atmospheric particles on health. Through this collection method, researchers can more carefully analyze the composition and morphology of nanoparticles of different particle sizes, and further understand their potential harm to human health.

[0016] The collection method of the particle size-resolved nanoparticle collection device of the present invention can calculate the landing point position of nanoparticles within the size range on the sample membrane according to the particle size of the nanoparticles to be collected, the thermophoresis speed, and the temperature gradient between the cold and hot plates, so that the sample membrane can collect nanoparticles of corresponding particle sizes; in addition, the present invention can also change the thermophoresis speed by regulating the gas flow rate or regulating the temperature gradient between the cold and hot plates, so that nanoparticles of a wider range of particle sizes can be collected without changing the position of the collector of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the particle collection principle of the present invention.

[0018] Figure 2 Schematic diagram of the external structure of an embodiment of the present invention.

[0019] Figure 3 Schematic diagram of the internal structure of an embodiment of the present invention.

[0020] Figure 4 It is a schematic diagram of the structure of a collector according to an embodiment of the present invention.

[0021] Figure 5 It is a schematic diagram of the structure of a collector according to an embodiment of the present invention.

[0022] Figure 6 It is a structural schematic diagram of a lever according to an embodiment of the present invention; Figure 7 The figure is a schematic diagram of the connection structure between the shift lever and the movable shaft according to an embodiment of the present invention.

[0023] Description of reference numerals: 1. Collector body, 2. Cold electrode plate, 3. Hot electrode plate, 4. Air inlet, 5. Air pump, 6. Film support frame, 7. Film support table, 8. Collecting hole, 9. Protective cavity, 10. Transmission shaft, 101. Fixed shaft, 102. Movable shaft, 103. First servo, 11. Lever, 111. Ring, 112. Connecting rod, 113. Rolling part, 12. Cam assembly, 121. Cam, 122. Second servo, 123. Cam groove, 13. Box, 14. Semiconductor cooling sheet, 15. Film support plate, 16. Radiator, 17. Retaining spring. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0025] Unless otherwise defined, the technical terms or scientific terms used herein should be understood by people with ordinary skills in the field to which the present disclosure belongs. "First", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before "include" or "comprise" cover the elements or objects listed after "include" or "comprise" and their equivalents, and do not exclude other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0026] The present embodiment provides a particle size-resolved nanoparticle collection device, including a collector and a collector, wherein the collector includes a collector body 1, a cold electrode plate 2 and a hot electrode plate 3, wherein the collector body 1 is provided with a collection chamber, wherein the cold electrode plate 2 is provided at the top of the collection chamber, and the hot electrode plate 3 is provided at the bottom of the collection chamber, wherein the collection chamber has an air inlet 4 connected to the atmosphere, and an outlet of the collection chamber is connected to an air pump 5; when nanoparticles need to be collected, gas carrying the nanoparticles enters the collection chamber through the air inlet 4 of the collection chamber, and since the top of the collection chamber is provided with a cold electrode plate 2 and the bottom is provided with a hot electrode plate 3, as shown in FIG. Figure 1 As shown, the cold plate 2 and the hot plate 3 are parallel and keep a certain distance a. There is a temperature gradient between the cold plate 2 and the hot plate 3. T, when the gas carrying a large amount of particles moves at a certain speed When flowing along the collection cavity, due to the temperature gradient between the cold electrode plate 2 and the hot electrode plate 3, the gas molecules in the hotter area have higher kinetic energy than the gas molecules in the colder area, resulting in uneven momentum transfer caused by the collision between the gas and the particle surface. The momentum transferred by the particle surface collision facing the hot electrode plate 3 is greater than that on the opposite side. Therefore, the interaction between the gas molecules and the particles causes a certain thermophoresis velocity to be generated from the hot electrode plate 3 to the cold electrode plate 2. , so that the particles move forward with the gas and also move toward the cold electrode plate 2, and finally hit the cold electrode plate 2. It should be noted that the nano-scale particles in this embodiment refer to particles of, for example, 10nm to 300nm, among which nano-particles of 66nm to 300nm can achieve particle size resolution when collected, and nano-particles of 10nm to 66nm can be effectively collected, but particle size resolution is difficult.

[0027] Compared with the traditional method of collecting particles by high-speed particle impact, the high-speed particle impact on the diaphragm may cause fragmentation and change the morphology of the particles. However, this embodiment does not have the above problem. Secondly, the traditional method of collecting particles by high-speed particle impact can only use inertial sampling when the particle size reaches a certain size. If the particle size is too small, the particle inertia is small and will flow away with the airflow, making it difficult to collect. Compared with the traditional collection method, the above collection method of this embodiment can collect particles with smaller particle sizes.

[0028] like Figure 3 , Figure 4 and Figure 5As shown, the collector of this embodiment includes a film support frame 6, two film support tables 7 and a film support frame driving unit. The two film support tables 7 are both arranged at the bottom end of the film support frame 6. The collector body 1 is provided with a collecting hole 8 that runs from the top of the collector body 1 to the inside of the collecting cavity. The collector body 1 is also provided with a protective cavity 9. The two film support tables 7 are respectively located in the collecting hole 8 and the protective cavity 9. The film support frame driving unit is used to complete the position exchange of the two film support tables 7 in the collecting hole 8 and the protective cavity 9. More specifically, the film support frame driving unit enables the The film support frame 6 moves up and down or drives the film support frame 6 to rotate, so that when one of the film support stages 7 is located in the collecting hole 8, the other film support stage 7 is located in the protective cavity 9, so that the sampling of the sample films on the two film support stages 7 can be completed continuously. In this embodiment, the bottom surfaces of the two film support stages 7 are located on the same horizontal plane. As a preferred embodiment, the bottom surface of the film support plate 15 in the collecting hole 8 and the lower surface of the cold electrode plate 2 are located on the same horizontal plane. At this time, the difference between the protective cavity 9 and the collecting hole 8 is that the protective cavity 9 is a blind hole, that is, the lower opening of the protective cavity 9 is closed. Figure 4 As shown, the protection cavity 9 is located at the side of the collector body 1, avoiding the area where the collection cavity and the cold electrode plate 2 are located, so as not to affect the sample collection.

[0029] Please refer again Figure 4 In this embodiment, the horizontal cross-sections of the protective cavity 9 and the collecting hole 8 are both rectangular, but it should be understood that the specific shape of the horizontal cross-section is not limited thereto and may also be other shapes. The two film support platforms 7 of this embodiment are adapted to the size and shape of the protective cavity 9 and the collecting hole 8, and in order to improve the sealing performance of the two film support platforms 7, the protective cavity 9 and the collecting hole 8, a sealing ring may be designed on the outer edge of the two film support platforms 7, or a sealing ring may be designed on the inner wall of the protective cavity 9 and the collecting hole 8 to ensure the sealing performance after the fitting. On this basis, the film support platform 7 of this embodiment includes a film support plate 15 and a sample film covered on the film support plate 15. Nanoparticles collected on the sample film can be directly used for subsequent detection and analysis. In this embodiment, the sample film is a conventional particle sample film in the prior art. In order to collect particles of different particle sizes, multiple sample films can be designed on the film support plate 15 of the film support platform 7 along the gas flow direction. Different sample films collect nanoparticles of different particle size ranges. The length of the film support platform 7 of this embodiment is about 30 mm, and it can carry 10 sample films.

[0030] Please refer again Figure 4 The specific structure of the collector of this embodiment can be as follows Figure 4As shown, it includes a collector body 1, a cold pole plate 2, a cold pole plate protection plate, a hot pole plate 3, and a hot pole plate protection plate. The collection chamber is arranged on one side of the collector body 1, and the collection chamber communicates with the outside through an air inlet 4 and an air outlet. A cold pole plate slot is arranged on the collection chamber, and a hot pole plate slot is arranged below. The cold pole plate 2 and the cold pole plate protection plate are successively arranged in the cold pole plate slot and fixed to the collector body 1 by screws. A collection hole 8 is arranged on the cold pole plate 2 and communicates with the sampling chamber, and a corresponding hole is also arranged on the cold pole plate protection plate on the cold pole plate 2. The hot electrode plate 3 and the hot electrode plate protective plate are successively arranged in the hot electrode plate slot and fixed to the collector body 1 by screws. The hot electrode plate 3 is heated by a resistance wire. The cold electrode plate 2 and the hot electrode plate 3 are respectively provided with temperature sensors. The air inlet 4, the air outlet, the cold electrode plate 2, the hot electrode plate 3 and the cavity of the collector body 1 together constitute a gas flow channel. The cold electrode plate 2, the cold electrode plate protective plate, the hot electrode plate 3 and the hot electrode plate protective plate are correspondingly provided with sealing strips to ensure the airtightness of the gas flow channel. The protective cavity 9 is symmetrically designed with the collection hole 8.

[0031] In this embodiment, at least one semiconductor cooling sheet 14 is arranged in each of the film support tables 7. Figure 5 As shown, there are two, but it should be understood that the specific number is not limited. The number of semiconductor refrigeration sheets 14 can also be 1 or 3, etc., as long as the use requirements are met. Each semiconductor refrigeration sheet 14 is connected to a heat sink 16, and the heat sink 16 is located on the film support table 7. More specifically, two positioning holes are provided on each film support table 7. The semiconductor refrigeration sheet 14 is embedded in the positioning holes, and its cooling surface is fixedly mounted on the film support plate 15. The two semiconductor refrigeration sheets 14 on the same film support table 7 are connected in series and connected to a 12V DC power supply. Each heat sink 16 is fixedly mounted on the heat dissipation surface of the semiconductor refrigeration sheet 14, and a film support plate 15 is also provided on the bottom surface of the film support table 7. A sample film for collecting particulate matter is arranged on the bottom surface of the film support plate 15. The semiconductor refrigeration sheet 14 is used to provide cooling to the film support plate 15, and the heat sink 16 is used to dissipate heat and cool the semiconductor refrigeration sheet 14.

[0032] As another preferred embodiment of the present invention, the film support frame driving part of the present invention comprises: a transmission shaft 10, a lever 11 and a cam assembly 12; wherein the transmission shaft 10 comprises a vertically arranged fixed shaft 101, a movable shaft 102 and a first steering gear 103; the top of the fixed shaft 101 is fixedly connected to the first steering gear 103, the bottom of the fixed shaft 101 is provided with a square hole along the axial direction, the top of the movable shaft 102 is a square shaft head, the square shaft head is located in the square hole, and a compression spring is provided between the square shaft head and the square hole, and the film support frame 6 is connected to the bottom end of the movable shaft 102; Figure 6 As shown, the lever 11 includes a collar 111, a connecting rod 112 and a rolling portion 113. The rolling portion 113 and the collar 111 are respectively located at two ends of the connecting rod 112. Figure 7As shown, the collar 111 is sleeved on the movable shaft 102, and one side of the collar 111 is fixed by a shaft shoulder, and the other side is fixed by a retaining spring 17; the cam assembly 12 includes a cam 121 and a second servo 122 for driving the cam 121 to rotate, and the outer surface of the cam 121 is provided with a cam groove 123, and the rolling portion 113 is embedded in the cam groove 123, and the rolling portion 113 can roll along the cam groove 123 when the cam 121 rotates.

[0033] As another preferred embodiment, the cold pole plate 2 and the hot pole plate 3 are both provided with temperature sensors for detecting the temperature on the cold pole plate 2 and the hot pole plate 3, so as to regulate the temperature gradient between the cold pole plate 2 and the hot pole plate 3, and regulate the landing position of nanoparticles of different particle sizes, so that particles of different particle size ranges fall on different sample films.

[0034] As another preferred embodiment, Figure 2 and Figure 3 As shown, the collector and the collector are both placed in the box 13, and the air pump 5 and the air inlet 4 of the collector are both located outside the box 13. As a more preferred embodiment, a fan is also provided in the box 13 for dissipating heat inside the box 13.

[0035] In order to more accurately collect nanoparticles within the target range, this embodiment also provides a collection method using the above-mentioned nanoparticle collection device with particle size resolution, which is as follows: The thermophoresis speed of the particles that follow the gas into the space between the cold plate 2 and the hot plate 3 needs to be considered in two cases. When (λ is the mean free path of gas molecules, for air at standard pressure, λ is 66nm), the thermophoresis velocity Particle size It is independent of the temperature gradient and is proportional to the temperature gradient. The resulting thermophoresis velocity is: , Formula 1, where T is the ambient temperature, T is the temperature gradient, is the viscosity of the gas, is the gas density. The “-” sign in the formula represents the direction of the thermophoresis velocity. The direction is from the hot plate 3 to the cold plate 2.

[0036] for In the case of a particle, a temperature gradient is established inside the particle, which affects the temperature of the surrounding gas and therefore also the temperature gradient near the particle. This effect depends on the particle size and the thermal conductivity of the surrounding gas. Thermal conductivity of particles The ratio of , so the coefficient H is introduced: , Formula 2, where It is determined according to the chemical composition of atmospheric particulate matter. In addition, when the particle size is close to the molecular mean free path, the Sinclair slip effect needs to be considered and a correction factor is introduced. : , Formula 3, where , , , therefore, for The thermophoretic velocity of the particles is: Formula 4, The thermophoretic velocity of particles decreases as the particle size increases.

[0037] When the distance a between the cold pole plate 2 and the hot pole plate 3 is constant, a gap is created between the cold pole plate 2 and the hot pole plate 3. Temperature gradient in °C / mm, The value range is 1~ 2. When When the amount of energy entering the collection chamber is calculated according to Formula 1 The maximum thermophoretic velocity of particles ,according to It can be seen that the shortest time for particles to hit the cold electrode plate 2 is , the particle velocity entering the collection chamber When a certain time is reached, the shortest distance of its horizontal movement , set the first sample membrane at this distance, and the particle size can be collected For particles of size According to Formula 4, as the particle size increases, the thermophoresis speed decreases, and the time it takes to hit the cold electrode plate 2 increases, which increases the horizontal movement distance and causes the particles to hit the sample membrane behind. Therefore, on the basis of determining the position of the first sample membrane, multiple sample membranes are continuously arranged along the air flow direction to realize the collection of nanoparticles of different particle sizes.

[0038] As another embodiment, the collection of nanoparticles with different particle size ranges can be regulated by adjusting the temperature gradient between the cold electrode plate 2 and the hot electrode plate 3 and the gas flow rate.

[0039] In order to accurately control the air flow entering the device, a regulating valve for regulating the intake air flow is installed at the air inlet of the air pump 5. As a preferred method, the regulating valve can be a needle valve or a solenoid valve. Two temperature sensors are respectively installed on the cold electrode plate 2 and the hot electrode plate 3, and the real-time monitored temperature is provided to the PID controller. The controller is connected to the cooling component of the cold electrode plate 2 and the heating component of the hot electrode plate 3 to adjust the temperature of the cold electrode plate 2 and the hot electrode plate 3 according to the set target temperature gradient. The regulating valve can also be connected to the controller to realize automatic regulation of the intake air volume.

[0040] like Figure 2 and Figure 3 As shown, a particle size-resolved nanoparticle collection device includes a box 13, an air pump 5, a zero filter, a fan, a collector and a collector, wherein the air pump 5 and the zero filter are arranged on the right side above the top cover of the box 13, two fans are arranged in the fan mounting holes on the rear side plate of the box 13, the collector is arranged on four positioning pins on the inner side of the bottom plate of the box 13 through four positioning holes, the air inlet 4 and the air outlet on the collector are respectively arranged in the slots reserved on the left and right sides of the box 13, the air inlet 4 is directly connected to the outside, the air outlet is connected to the zero filter, the zero filter is used to prevent particles from entering the air pump 5, and then connected to the air pump 5, and a needle valve is provided at the air inlet of the air pump 5. The collector is arranged in the shaft hole of the top cover of the box body 13 through the upper fixed shaft 101, the first servo 103 is arranged above the top cover of the box body 13 and connected to the fixed shaft 101, and the two film supporting platforms 7 on the film supporting frame 6 are arranged directly above the collecting hole 8 and the protective cavity 9 on the cold electrode plate protective plate.

[0041] A handle is provided on the left side above the top cover of the box body 13, and the top cover of the box body 13 is installed on the upper end of the right side plate through a pin shaft so that the collector can be moved out of the box body 13. A visual window for installing organic glass is provided on the front side plate of the box body 13, and two fan mounting holes are symmetrically provided on the rear side plate of the box body 13. Four positioning pin shafts are symmetrically arranged on the inner side of the bottom plate of the box body 13, and a compression spring is provided on the positioning pin shaft.

[0042] The collection method of the above-mentioned collection device of this embodiment is as follows: In this embodiment, the sample film for collecting nanoparticles is set on the bottom surface of the film support plate 15, and the sample film and the bottom surface of the film support plate 15 can be bonded or clamped. When working, the second steering engine 122 is started to rotate the cam 121 180°, and the movable shaft 102 is driven by the lever 11 to push the film support frame 6 to move downward, so that the film support table 7 enters the collection hole 8, and the film support plate 15 is tightly fitted with the cold electrode plate 2 on the collector, and the air pump 5 is started to allow the gas to enter the collection cavity through the air inlet 4 and collect nanoparticles of different particle sizes through the sample membrane. After one collection is completed, the second steering engine 122 is started to rotate 180°, the film support frame 6 is lifted, and the film support table 7 is driven to separate from the collector. , the first steering gear 103 drives the film supporting table 7 to rotate 180°, and the two film supporting tables 7 exchange positions. The second steering gear 122 is started again to rotate 180°, driving the sample film supporting frame 6 to move downward, so that the second film supporting table 7 enters the collecting hole 8. At the same time, the film supporting table 7 that has completed the first collection enters the protective cavity 9 to prevent air from contaminating the collected sample film. The temperature gradient between the cold electrode plate 2 and the hot electrode plate 3 or the flow rate of the air pump 5 is reset to carry out the second collection. After the collection is completed, the second steering gear 122 is started again to rotate 180°, the film supporting frame 6 is lifted, driving the film supporting table 7 to separate from the collecting hole 8, turning off the air pump 5, pulling the handle on the top cover of the box body 13, taking out the collector, removing the sample film, and completing the entire collection process.

[0043] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A nanoparticle collection device with particle size resolution, characterized in that: include: A collector, comprising a collector body (1), a cold electrode plate (2) and a hot electrode plate (3), wherein a collection chamber is provided in the collector body (1), the cold electrode plate (2) is arranged at the top of the collection chamber, and the hot electrode plate (3) is arranged at the bottom of the collection chamber, the collection chamber has an air inlet (4) connected to the atmosphere, and the outlet of the collection chamber is connected to an air pump (5); A collector comprises a film support frame (6), two film support tables (7) and a film support frame driving unit, wherein the two film support tables (7) are both arranged at the bottom end of the film support frame (6), the film support tables (7) are used to carry a sample film, and the sample film is located at the bottom of the film support tables (7); the collector body (1) is provided with a collecting hole (8) extending from the top of the collector body (1) to the inside of the collecting cavity, the collector body (1) is also provided with a protective cavity (9), the two film support tables (7) are respectively located in the collecting hole (8) and the protective cavity (9), and the film support frame driving unit is used to enable the two film support tables (7) in the collecting hole (8) and the protective cavity (9) to complete the position exchange.

2. The nanoparticle collection device for particle size resolution according to claim 1, characterized in that: At least one semiconductor cooling sheet (14) is arranged in the film supporting platform (7), a film supporting plate (15) made of the same material as the cold electrode plate (2) is arranged at the bottom of the film supporting platform (7), the sample film is located at the bottom of the film supporting plate (15), the semiconductor cooling sheet (14) is used to provide cooling to the film supporting plate (15), and a radiator (16) is arranged on the film supporting platform (7) for dissipating heat and cooling the semiconductor cooling sheet (14).

3. The nanoparticle collection device for particle size resolution according to claim 1, characterized in that: The film support frame driving unit comprises: The transmission shaft (10) comprises a vertically arranged fixed shaft (101), a movable shaft (102) and a first steering gear (103); the top of the fixed shaft (101) is fixedly connected to the first steering gear (103); the bottom of the fixed shaft (101) is provided with a square hole along the axial direction; the top of the movable shaft (102) is a square shaft head, the square shaft head is located in the square hole, and a compression spring is provided between the square shaft head and the square hole; the film support frame (6) is connected to the bottom end of the movable shaft (102); A lever (11) comprising a collar (111), a connecting rod (112) and a rolling portion (113), wherein the rolling portion (113) and the collar (111) are respectively located at two ends of the connecting rod (112), the collar (111) is sleeved on the movable shaft (102), and one side of the collar (111) is fixed by a shaft shoulder, and the other side is fixed by a retaining spring (17); A cam assembly (12) comprises a cam (121) and a second servo (122) for driving the cam (121) to rotate, wherein a cam groove (123) is provided on the outer surface of the cam (121), a rolling portion (113) is embedded in the cam groove (123), and the rolling portion (113) can roll along the cam groove (123) when the cam (121) rotates.

4. The nanoparticle collection device for particle size resolution according to claim 1, characterized in that: The cold pole plate (2) and the hot pole plate (3) are both provided with temperature sensors.

5. The nanoparticle collection device for particle size resolution according to claim 1, characterized in that: A regulating valve for regulating the intake air flow rate is installed at the air inlet of the air pump (5).

6. The nanoparticle collection device for particle size resolution according to claim 1, characterized in that: A sealing ring is provided on the outer periphery of the film supporting platform (7) or the inner wall of the collecting hole (8) and the protective cavity (9).

7. The collection method of the nanoparticle collection device with particle size resolution as claimed in claim 1, characterized in that: The following steps are involved: When the particle size of the particles to be collected is When , the thermophoresis velocity of nanoparticles is: , where λ is the mean free path of gas molecules; T is the ambient temperature, T is the temperature gradient, is the viscosity of the gas, is the gas density; When the particle size of the particles to be collected is When , the thermophoresis velocity of nanoparticles is: ; where H is the coefficient, is the correction factor; When the distance between the cold pole plate (2) and the hot pole plate (3) is determined, a gap is created between the cold pole plate (2) and the hot pole plate (3). Temperature gradient in °C / mm, The value range is 1~ 2. When When the time of entering the collection cavity is calculated The maximum thermophoretic velocity of nanoparticles ,according to , and the shortest time for the nanoparticles to hit the cold plate (2) is obtained , where a is the distance between the two plates; when the nanoparticles entering the collection chamber have a speed of At a certain time, the shortest distance that particles move horizontally between the cold plate (2) and the hot plate (3) is , at the shortest distance Set the first sample membrane to collect the particle size of particulate matter; For particle size The particles will hit the sample membrane behind the first sample membrane, realizing the collection of particles of different sizes.

8. The collection method of the nanoparticle collection device with particle size resolution according to claim 7, characterized in that: The correction factor : ,in , , , is the particle size of the particles.

9. The collection method of the nanoparticle collection device with particle size resolution according to claim 7, characterized in that: Definition of coefficient H: ,in is the thermal conductivity of the particles, is the thermal conductivity of the surrounding gas, is the particle size of the particles.

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