Low-concentration aerosol generating method and generating device thereof

Abstract

The present application relates to the field of fine particulate matter / inhalable particulate matter mass concentration monitor calibration, and particularly relates to a low-concentration aerosol generating method and a generating device thereof. The low-concentration aerosol is formed by adopting electromagnetic mechanical vibration and ultrasonic resonance dust emission, Venturi tube conveying, mixing and dilution, and is uniform and stable.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fine particulate matter / inhalable particulate matter mass concentration monitor calibration, and particularly relates to a low-concentration aerosol generating method and a generating device thereof. BACKGROUND

[0002] Aerosol, in English, refers to a gaseous dispersion system composed of solid or liquid particles suspended in a gaseous medium. At present, standard particles are used to calibrate and detect fine particulate matter protection equipment and monitoring instruments at home and abroad, but the physical and chemical properties of fine particulate matter in the air change easily, resulting in a large deviation between the production of standard particles and their application. One of the first problems to be solved for the performance research of fine particulate matter monitoring instruments and fine particulate matter protection equipment is the stability of the test aerosol, that is, an aerosol generator capable of generating fine particulate matter aerosol particles that meet the test requirements needs to be developed. On the other hand, real-time generation and detection technology of low-concentration fine particulate matter can effectively improve efficiency and accuracy and save costs, so it is of great significance to develop low-concentration fine particulate matter generation devices and detection methods.

[0003] Traditional aerosol generating devices are either liquid atomization methods, or directly send solid powders into a mixing box after grinding, or directly send powder particles into a mixing box. The liquid atomization method can only obtain single-particle-size particles, and the particle concentration cannot be stable for a long time, and the amount of liquid particles is large. Directly sending solid powders into a mixing box after grinding and directly sending powder particles into a mixing box to prepare aerosols have stability affected by environmental temperature and humidity, airflow, powder material, etc., and are often suitable for high-concentration particle generation and cannot generate low-concentration aerosols.

[0004] Chinese patent application 202310300944X discloses a biological aerosol generating system, and the publication number is CN116251545A. The biological aerosol generating system uses a liquid atomization method, separates large-particle-size and medium-particle-size particles under the dual action of gravity and different airflows through a shunt component, and then uses an electromigration device to separate ultra-small particles by the difference in moving speed of particles in an electric field, so that the device can generate small-particle-size particles with more accurate particle size range, and the aerosol particle size and concentration are controllable. This method is only suitable for single-type aerosol particles, and the relative concentration is relatively large, and is not suitable for the generation of aerosols with complex particle types and low concentration.

[0005] Another Chinese patent application 2023109995230 discloses a kind of ultrasonic driving type dust aerosol generating system, and the publication number is CN116983870A, which utilizes ultrasonic wave to generate dust, mixes and dilutes through Venturi pump, and outputs low-concentration dust aerosol.But the power of generating dust is completely from ultrasonic wave, and the energy is low, the dust generating effect is poor, in addition, low-concentration aerosol is often greatly affected by static electricity, forming agglomeration effect, affecting the stability of aerosol. SUMMARY

[0006] One of the purposes of the present application is to provide a low-concentration aerosol generating method, which can efficiently and conveniently form stable low-concentration aerosol.

[0007] The low-concentration aerosol generating method provided by the present application comprises the following method steps:

[0008] Step S1, air is extracted by an air compressor to prepare compressed air, then the compressed air is cooled and dried by a cold dryer, filtered by an air filter to obtain sample air, and the sample air is output in three ways;

[0009] Step S2, the dust particles are placed in a particle generating bottle, the particle generating bottle is placed in a water bath, the particle generating bottle is vibrated by a vibration device to make the dust particles float in the particle generating bottle, an ultrasonic generator arranged in the water bath acts on the outer wall of the particle generating bottle and conducts to the gas in the bottle, so that the environment in the bottle resonates and promotes the further diffusion of the dust particles floating in the particle generating bottle;

[0010] Step S3, a Venturi tube is arranged at the bottle opening of the particle generating bottle, one of the sample air in step S1 is connected to the input end of the Venturi tube, the dust particles suspended in the particle generating bottle are sucked by the negative pressure formed by the Venturi tube and discharged from the output end of the Venturi tube to form a primary aerosol;

[0011] Step S4, the primary aerosol obtained in step S3 and the remaining two ways of sample air in step S1 are simultaneously input into a mixing bin to obtain a low-concentration aerosol as a standard gas.

[0012] Through the above technical solution, the dust particles enclosed in the particle generating bottle are suspended in the bottle body by the vibration device, and then the ultrasonic wave beam is transmitted to the particle generating bottle through the medium to form high-frequency mechanical vibration, so as to stir or disperse the dust particles placed in the particle generating bottle, achieve better mixing and dispersion effect, then use the Venturi effect to suck the gas in the bottle to form aerosol gas, and finally dilute and mix in the dilution and mixing bin to form stable low-concentration aerosol.

[0013] Preferably, the flow of the sample air output to the input end of the Venturi tube is controlled by the flow valve in step S3: the flow of the sample air output to the dilution and mixing bin is controlled by the flow valve in step S4, and the sample air prepared in step S1 is heated before being input to the mixing bin.

[0014] By the above technical solution, the output flow of the Venturi tube and the dilution ratio of the low-concentration aerosol can be accurately controlled.

[0015] Another object of the present application is to provide a low-concentration aerosol generating device capable of efficiently and conveniently forming stable low-concentration aerosol.

[0016] The low-concentration aerosol generating device according to the present application comprises a sample air generating module, a particulate matter generating module, and a dilution and mixing module.

[0017] The sample air generating module comprises an air compressor, a cold dryer, and an air filter connected in series; the output end of the air filter is provided with a generating module interface connected to the particulate matter generating module and a mixing module interface connected to the mixing module;

[0018] The particulate matter generating module comprises a particulate matter generating bottle, a Venturi tube arranged at the bottle opening of the particulate matter generating bottle, a water tank arranged at the bottom of the particulate matter generating bottle, and an ultrasonic generator installed in the water tank; the throat portion of the Venturi tube is provided with a negative pressure pipe communicated into the inner cavity of the particulate matter generating bottle; the input end of the Venturi tube is connected to the generating module interface, and the output end is connected to the mixing module; the particulate matter generating bottle is installed in the water tank through a suspension bracket, and the bottom surface of the particulate matter generating bottle is lower than the water surface in the water tank; a vibration device is arranged between the particulate matter generating bottle and the water tank.

[0019] The dilution and mixing module comprises a mixing bin, a sample air input interface and an aerosol input interface arranged at the upper end of the mixing bin, and a standard gas output interface and a pressure relief port arranged at the lower end of the mixing bin.

[0020] By the above technical solution, the vibration device and the ultrasonic generator jointly act on the dust particles in the particulate matter generating bottle to efficiently generate uniform and stable aerosol; the negative pressure formed by the Venturi tube sucks the aerosol into the mixing bin for dilution and mixing, thereby generating stable low-concentration aerosol.

[0021] Preferably, a metal anti-static mesh is arranged in the inner cavity of the output end of the Venturi tube, and an anti-static sticker is arranged on the outer wall of the mixing bin; the metal anti-static mesh and the anti-static sticker are electrically connected to the ground wire through a wire.

[0022] By the above technical solution, the electrostatic cohesion of the dust particles in the aerosol can be eliminated, and the stability of the aerosol can be improved.

[0023] Preferably, the metal anti-static net comprises a sleeve ring sleeved on the outer wall of the venturi output end, elastic spokes arranged through the outer wall of the venturi output end, and a plurality of concentric rings arranged concentrically with the inner cavity of the venturi output end.

[0024] Through the above technical solution, the metal anti-static net has a large contact area with the aerosol, and has good static electricity removal effect. The vibration formed when the airflow passes through the metal anti-static net can prevent dust particles from being adsorbed on the net surface and prevent the net surface from being blocked.

[0025] Preferably, the vibration device is an electromagnet arranged at the bottom of the suspension bracket 11.

[0026] Through the above technical solution, the vibration frequency can be conveniently adjusted.

[0027] Preferably, the input end of the venturi and the sample air input interface are each provided with a flow valve for adjusting the airflow flow rate, the inner cavity of the mixing bin is provided with a funnel communicating with the standard gas output interface, and the pressure relief port is provided with a pressure relief valve and a pressure relief filter.

[0028] Through the above technical solution, the dilution ratio of the low-concentration aerosol can be conveniently adjusted.

[0029] Compared with the prior art, the beneficial effects of the present application are that the dry powder particles can be simultaneously subjected to ultrasonic, vibration, heating, stirring and feeding, and a uniform and stable low-concentration aerosol can be generated. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a schematic diagram of the principle of an embodiment of the present application.

[0031] Figure 2 is a structural schematic diagram of the metal anti-static net. DETAILED DESCRIPTION

[0032] The present application will be further described in detail below with reference to the accompanying drawings. Identical parts are denoted by identical reference numerals in the following description. It should be noted that the words "front", "back", "left", "right", "up" and "down" used in the following description refer to the directions in the drawings, and the words "bottom surface" and "top surface", "inner" and "outer" refer to the directions towards or away from the geometric center of a particular part.

[0033] As shown in Figure 1 , the low-concentration aerosol generation method of the present application comprises the following method steps:

[0034] Step S1, compressed air is prepared by extracting air with an air compressor, then the compressed air is cooled and dried by a cold dryer, and filtered by an air filter to obtain sample air, and the sample air is output in three ways; the air compressor and the cold dryer are both commercial machines purchased in the market, and the air filter is filtered by C, T and A three levels, so that impurities and oil droplets with a particle size of 0.01 μm are filtered out, and the filtered air reaches the level of medical air.

[0035] Step S2, the dust particles are placed in a particle generator bottle, the particle generator bottle is placed in a water bath, the water bath is set to 70 degrees Celsius to heat the particle generator bottle, the vibration device drives the particle generator bottle to vibrate to make the dust particles float in the particle generator bottle, and the ultrasonic generator arranged in the water bath acts on the outer wall of the particle generator bottle and conducts to the gas in the bottle, so that the environment in the bottle resonates, and promotes the further diffusion of the dust particles floating in the particle generator bottle; the vibration device promotes the dust particles in the particle generator bottle to float up when it works. The ultrasonic generator uses ultrasonic vibration to generate mechanical energy. When the ultrasonic beam passes through the medium from the inside of the vibration unit, high-frequency mechanical vibration is generated and conducted to the gas in the bottle, so that the environment in the bottle resonates, thereby stirring or dispersing the dust particles placed in the vibration unit. Its amplitude can reach micron level, which can generate stirring force, shear force, jetting force and other forces, so that the dust particles are subjected to strong mechanical force, thereby realizing mixing and dispersion. The dust particles have the characteristics of moisture absorption and condensation, and the fine particulate matter is particularly significant. Water bath heating can ensure that the dust particles in the bottle are dry and prevent moisture from agglomerating, and the water bath temperature of the water bath in this embodiment is 70°C.

[0036] Step S3, a Venturi tube is arranged at the bottle opening of the particle generator bottle, one of the sample air outputs in step S1 is connected to the input end of the Venturi tube, and the suspended dust particles in the particle generator bottle are sucked by the negative pressure formed by the Venturi tube and discharged from the output end of the Venturi tube to form the original aerosol. The Venturi tube is a pipe with a gradually expanding inner diameter after contraction, when the gas flows in the Venturi tube, the dynamic pressure reaches the maximum value and the static pressure reaches the minimum value at the narrowest part of the pipe, and the velocity of the gas rises because the through-flow cross-sectional area decreases, so the pressure also decreases at the same time. Further, a pressure difference is generated between the inside and outside of the pipe, which is used to measure or provide an external suction force for the fluid. The method of using negative pressure suction of the Venturi tube at the bottle opening of the particle generator bottle only sucks the aerosol particles with good stability suspended in the air, which can avoid the mixing of larger particles and affect the stability of the aerosol.

[0037] Step S4, the original aerosol obtained in step S3 and the two-way sample air remaining in step S1 are simultaneously input into a mixing bin to obtain a low-concentration aerosol as a standard gas. In order to ensure the stability of the aerosol in the mixing bin, the mixing bin can be heated and kept warm to keep the temperature of the aerosol in the mixing bin constant.

[0038] As a further improvement of the method of the present application, in order to accurately control the air flow in the Venturi tube and the dilution ratio of the low-concentration aerosol, the flow of the sample air output to the input end of the Venturi tube is controlled by a flow valve in step S3.

[0039] In step S4, the flow of the sample air output to the dilution and mixing bin is controlled by a flow valve, and the sample air prepared in step S1 is heated before being input into the mixing bin to make its temperature comparable to that of the original aerosol obtained in step S3. In this way, deformation of fine particulate matter due to moisture and agglomeration of wet particles can be prevented, and the stability of the aerosol can be improved. The humidity in the standard aerosol environment is kept below 50% RH.

[0040] The low-concentration aerosol generating device of the present application comprises a sample air generating module, a particulate matter generating module, and a dilution and mixing module.

[0041] As shown in Figure 1 The sample air generating module comprises an air compressor, a cold dryer and an air filter connected in series. The air compressor extracts air to prepare compressed air, the cold dryer cools and dries the compressed air, and the air filter filters out impurities to obtain sample air. The output end of the sample air generating module is provided with three sample air output joints. The three sample air output joints are respectively an occurrence module interface 91 connected to the particulate matter generating module and a mixing module interface 92 connected to the mixing module.

[0042] The particulate matter generating module comprises a particulate matter generating bottle 1, a Venturi tube 2 arranged at the bottle opening of the particulate matter generating bottle 1, a water tank 3 arranged at the bottom of the particulate matter generating bottle 1, and an ultrasonic generator 4 installed in the water tank 3. The throat portion of the Venturi tube 2 is provided with a negative pressure pipe 20 communicating with the inner cavity of the particulate matter generating bottle 1. The input end of the Venturi tube 2 is connected to the occurrence module interface 91, and the output end is connected to the mixing module. The particulate matter generating bottle 1 is installed in the water tank 3 by a suspension bracket 11, and the bottom surface of the particulate matter generating bottle 1 is lower than the water surface in the water tank 3. A vibration device is arranged between the particulate matter generating bottle 1 and the water tank 3. The part of the suspension bracket 11 in contact with the bottom of the particulate matter generating bottle 1 is provided with a through hole, so that the bottom of the particulate matter generating bottle 1 can be in contact with the water in the water tank 3 through the through hole.

[0043] The vibration device is an electromagnet arranged at the bottom of the suspension bracket 11. In this embodiment, the electromagnet comprises an armature 6 fixedly installed at the bottom of the suspension bracket 11, and a coil 61 fixedly installed in the water tank 3 and adapted to the armature 6. The water tank 3 can have a rectangular or circular structure, and the edge of the water tank 3 is provided with an elastic rubber ring 31, and the two sides of the suspension bracket 11 are overlapped on the elastic rubber ring 31, so that the suspension bracket 11 can move up and down within the elastic range of the elastic rubber ring 31, forming a floating connection. The coil 61 is arranged around the armature 6, and when an alternating current of a certain frequency is passed through the coil 61, the armature 6 can be continuously attracted to drive the suspension bracket 11 and the particulate matter generating bottle 1 to vibrate up and down.

[0044] The particulate matter generating bottle 1 is installed on the suspension bracket 11, and is driven by the vibration device to vibrate in the vertical direction, so that the dust particles in the particulate matter generating bottle are raised and suspended in the upper half of the particulate matter generating bottle, and different vibration frequencies can adjust the dust concentration. At the same time, the suspended particulate matter in the particulate matter generating bottle is subjected to ultrasonic oscillation by the ultrasonic generator, and at a lower power, the ultrasonic wave can disperse and crush smaller particle agglomerates, and at a higher power, the ultrasonic wave can generate high-intensity shear force to crush large particle agglomerates, thereby reducing the suspended dust particle agglomerates, and further forming a good quality aerosol. By using different combinations of vibration frequencies and ultrasonic powers, the concentration of the generated aerosol can be adjusted, and different dust materials can be used with different vibration frequencies and ultrasonic powers.

[0045] In use, standard dry dust particles for dust generation are placed in the particulate matter generating bottle 1, which can be selected according to the requirements of detection or experiments, such as road dust, ISO dust, SAE dust and PSL dry powder. Clean water is injected into the water tank 3 so that the clean water covers the bottom of the particulate matter generating bottle 1, and if there is a certain requirement for the temperature of the aerogel, a heating and insulation device can be arranged in the water tank 3, and the water bath temperature is set to 70 degrees Celsius during operation. The vibration device is turned on to vibrate the particulate matter generating bottle 1, and the dust particles at the bottom of the particulate matter generating bottle 1 are floated in the particulate matter generating bottle 1, and the ultrasonic generator 4 is turned on to make the particulate matter generating bottle 1 resonate with the ultrasonic wave, so that the dust particles are subjected to strong mechanical force, thereby promoting the further diffusion of the dust particles floating in the particulate matter generating bottle 1. When the input end of the Venturi tube 2 is connected to the module interface 91 and the sample air flow passes through the sample air flow, the dust particles diffused into the particulate matter generating bottle 1 are sucked into the Venturi tube 2 by the negative pressure pipe 20 and mixed with the sample air to form the original aerosol.

[0046] Because the density of water is much greater than that of air, the wavelength of ultrasonic waves is shorter when they propagate in water than when they propagate in air. This means that at the same frequency, sound waves in water are more easily absorbed or scattered than sound waves in air. In addition, due to the surface tension of water, sound waves are reflected and refracted when they propagate in water, which makes the propagation of sound waves in water more complex. The conduction effect of ultrasonic waves is more obvious.

[0047] The ultrasonic power is set to 50 kHz, and the vibration frequency is set to 0 Hz, 2 Hz, and 5 Hz, respectively. The comparative experiments of dust emission by ultrasonic waves through and not through water medium are carried out, and the dust emission concentration experimental data are as follows:

[0048]

[0049] In this comparative experiment, through water means that the ultrasonic generator and the particle generator bottle are placed in the water tank, and the two do not directly contact. The ultrasonic waves act on the particle generator bottle through the conduction of water. Not through water means that the particle generator bottle is placed in a water-free environment, and the ultrasonic generator is attached to the bottom of the particle generator bottle. The ultrasonic waves directly act on the particle generator bottle.

[0050] The stability test is that the generating device is normally operated for 5 minutes under fixed ultrasonic power and vibration frequency. A data is recorded every 1 minute, 10 times are recorded, the maximum value is subtracted from the minimum value, and the maximum difference in 10 groups of data is calculated. The stability is the maximum concentration value divided by the maximum difference. The smaller the stability result is, the more stable the dust emission is, and the larger the result is, the more unstable it is.

[0051] The stability formula is

[0052]

[0053] The dust emission concentration is that the generating device is normally operated for 5 minutes under fixed ultrasonic power and vibration frequency. A data is recorded every 1 minute, 10 times are recorded, and the average value of the concentration of 10 times is the concentration of dust emission.

[0054] The formula of dust emission concentration is

[0055]

[0056] The repeatability is that the concentration data is recorded after the generating device is normally operated for 5 minutes under fixed ultrasonic power and vibration frequency. The concentration data is recorded 10 times, and the relative standard deviation is calculated as the repeatability. The greater the repeatability is, the worse the reproducibility is, and vice versa.

[0057] The repeatability formula is

[0058]

[0059] The contrast experiment shows that the ultrasonic conduction through water applied to the particulate matter generating bottle is significantly superior to the scheme of ultrasonic direct action on the particulate matter generating bottle in terms of dust emission concentration, repeatability and stability.

[0060] In addition, different vibration frequencies and ultrasonic powers have a great influence on the dust emission concentration, as shown in the following table

[0061]

[0062] The dilution and mixing module comprises a mixing bin 5, a sample air input interface 51 and an aerosol input interface 52 arranged at the upper end of the mixing bin 5, a standard gas output interface 53 and a pressure relief port 54 arranged at the lower end of the mixing bin 5. The mixing bin 5 is a circular cylinder structure with arc-shaped top ends, made of 304 stainless steel plate, and the inner wall surface is polished to a surface roughness of less than 0.0025mm to prevent static electricity and particle adsorption.

[0063] The original aerosol output by the Venturi tube 2 and the sample air output by the mixing module interface 92 are input into the mixing bin 5 from the aerosol input interface 52 and the sample air input interface 51 at the upper end of the mixing bin 5, respectively, collide and mix in the mixing bin 5, and the particles are mixed uniformly through the turbulent flow of the internal flow field. The longest residence time of the gas flow is designed to be 21 seconds, and finally the diluted low-concentration aerosol is output from the standard gas output interface 53, ensuring that the particle concentration and particle size distribution deviation collected by different instruments do not exceed 5%.

[0064] Dry dust particles usually have static electricity, which can make dust agglomerate and settle more easily, adsorb and destroy the stability of aerosol.

[0065] As a further improvement of the present application, a metal anti-static mesh 21 is arranged in the inner cavity of the output end of the Venturi tube 2, and an anti-static sticker 55 is arranged on the outer wall of the mixing bin 5. The metal anti-static mesh 21 and the anti-static sticker 55 are both electrically connected to the ground wire through a wire. The metal anti-static mesh 21 and the anti-static sticker 55 are both made of conductive metal material and can release static electricity after being electrically connected to the ground wire.

[0066] As Figure 2As shown, the metal anti-static net 21 is made of stainless steel as a whole, including a sleeve ring 22 sleeved on the outer wall of the output end of the Venturi tube 2, elastic spokes 33 penetrating through the outer wall of the output end of the Venturi tube 2, and a plurality of concentric rings 34 concentrically arranged in the inner cavity of the output end of the Venturi tube 2. The concentric rings 34 and the elastic spokes 33 are both made of thin stainless steel wires. When the airflow passes through the Venturi tube 2, the airflow blows the metal anti-static net 21 to make the concentric rings 34 and the elastic spokes 33 vibrate, collide with the dust particles in the airflow, and release the static electricity in the dust particles, while avoiding the dust particles from being adsorbed on the metal anti-static net 21.

[0067] In addition, in order to facilitate the control of the dilution ratio of the aerosol, the input end of the Venturi tube 2 and the sample air input interface 51 are both provided with flow valves for adjusting the airflow flow rate, the inner cavity of the mixing bin is provided with a funnel communicating with the standard gas output interface 53, and the pressure relief port 54 is provided with a pressure relief valve 541 and a pressure relief filter 542. The flow rate and airflow speed of the sample air input into the Venturi tube 2 can be controlled through the flow valve of the input end of the Venturi tube 2, and the flow rate and airflow speed of the sample air input into the mixing bin 5 can be controlled through the flow valve of the sample air input interface 51. In this embodiment, two sample air input interfaces 51 are simultaneously connected to the mixing bin 5, so that a larger adjustment range can be obtained.

[0068] Although some specific embodiments of the present application have been described in detail above, those skilled in the art should understand that the above examples are only for illustration, and are not intended to limit the scope of the present application. Those skilled in the art should understand that the above embodiments can be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. A low-concentration aerosol-generating method, characterized by, The method comprises the following steps: Step S1, compressed air is prepared by using an air compressor to extract air, and then the compressed air is cooled and dried by using a cold dryer, and filtered by using an air filter to obtain sample air, and the sample air is output in three ways; Step S2, the dust particles are placed in a particle generating bottle, the particle generating bottle is placed in a water bath tank, and the particle generating bottle is vibrated by using a vibration device to make the dust particles float in the particle generating bottle, an ultrasonic generator arranged in the water bath tank acts on the outer wall of the particle generating bottle and is transmitted to the gas in the bottle, so that the environment in the bottle resonates and promotes the further diffusion of the dust particles floating in the particle generating bottle; Step S3, a Venturi tube is arranged at the bottle opening of the particle generating bottle, one of the sample air outputs in step S1 is connected to the input end of the Venturi tube, and the dust particles suspended in the particle generating bottle are sucked by the negative pressure formed by the Venturi tube and discharged from the output end of the Venturi tube to form a primary aerosol; Step S4, the primary aerosol obtained in step S3 and the remaining two ways of sample air in step S1 are simultaneously input into a mixing bin to obtain a low-concentration aerosol as a standard gas.

2. The low-concentration aerosol generating method of claim 1, wherein, In step S3, the flow rate of the sample air output to the input end of the Venturi tube is controlled by a flow valve: In step S4, the flow rate of the sample air output to the mixing bin is controlled by a flow valve, and the sample air prepared in step S1 is heated before being input into the mixing bin.

3. A low-concentration aerosol generating device, comprising a sample air generating module, a particle generating module, and a dilution and mixing module, characterized in that: The sample air generating module comprises an air compressor, a cold dryer and an air filter connected in series, and the output end of the air filter is provided with a generating module interface (91) connected to the particle generating module and a mixing module interface (92) connected to the mixing module; The particle generating module comprises a particle generating bottle (1), a Venturi tube (2) arranged at the bottle opening of the particle generating bottle (1), a water tank (3) arranged at the bottom of the particle generating bottle (1), and an ultrasonic generator (4) installed in the water tank (3), wherein the throat portion of the Venturi tube (2) is provided with a negative pressure pipe (20) communicated into the inner cavity of the particle generating bottle (1), the input end of the Venturi tube (2) is communicated with the generating module interface (91), and the output end is connected to the mixing module, the particle generating bottle (1) is installed in the water tank (3) through a suspension bracket (11), and the bottom surface of the particle generating bottle (1) is lower than the water surface in the water tank (3), and a vibration device is arranged between the particle generating bottle (1) and the water tank (3); The dilution and mixing module comprises a mixing bin (5), a sample air input interface (51) and an aerosol input interface (52) arranged at the upper end of the mixing bin (5), and a standard gas output interface (53) and a pressure relief port (54) arranged at the lower end of the mixing bin (5).

4. The low-concentration aerosol-generating device according to claim 3, characterized in that: The inner cavity of the output end of the Venturi tube (2) is provided with a metal anti-static net (21), the outer wall of the mixing bin (5) is provided with an anti-static sticker (55), and the metal anti-static net (21) and the anti-static sticker (55) are electrically connected with the ground wire through wires.

5. A low-concentration aerosol-generating device according to claim 4, wherein: The metal anti-static net (21) comprises a sleeve ring (22) sleeved on the outer wall of the output end of the Venturi tube (2), elastic spokes (33) penetrating through the outer wall of the output end of the Venturi tube (2), and a plurality of concentric rings (34) concentrically arranged in the inner cavity of the output end of the Venturi tube (2).

6. A low-concentration aerosol-generating device according to claim 3 or 4, wherein: The vibrating device is an electromagnet arranged at the bottom of the suspension support (11).

7. A low-concentration aerosol-generating device according to claim 3 or 4, wherein: The input end of the Venturi tube (2) and the sample air input interface (51) are both provided with flow valves for adjusting the flow rate of air flow, the inner cavity of the mixing bin is provided with a funnel communicating with a standard gas output interface (53), and the pressure relief port (54) is provided with a pressure relief valve (541) and a pressure relief filter (542).

Images