Generating device for standard particles with wide particle size range

Abstract

The invention provides a wide particle size range standard particle generating device which comprises an aerosol generating unit and an aerosol processing unit, and the aerosol generating unit comprises a first aerosol atomizer and a second aerosol atomizer; the aerosol treatment unit comprises a first uniform mixing chamber, a heating uniform mixing chamber, a virtual cutter and a uniform mixer, an electrostatic neutralizer is mounted at the upper end of the first uniform mixing chamber, the lower part of the virtual cutter is connected with a cutter air exhaust nozzle, and small particles are discharged from the virtual cutter by strong airflow generated by a micro negative pressure air pump; the upper part of the mixer is connected with an air supply filter, and a static mixer is mounted in the mixer. The device is high in integration degree, and aerosol with the particle size ranging from 0.1 micrometer to 10 micrometers can be output. And the conveying pipelines are mainly arranged vertically, so that the loss of particles caused by gravity settling is effectively reduced. According to the aerosol processing unit, the virtual cutter is applied to aerosol particle size grading, background residual particles can be reduced, and monodispersity is improved.

Description

A standard particle generator with a wide particle size range Technical Field

[0001] This invention belongs to the field of aerosol generating equipment, and particularly relates to a standard particle generating device with a wide particle size range. Background Technology

[0002] In the field of aerosol generation and particle counter calibration technology, the generation of large-particle-size standard aerosols in the range of 1-10μm is the core prerequisite for achieving accurate particle counter calibration and ensuring the reliability of clean environment detection. It is widely used in industries with extremely high requirements for particle contamination control, such as semiconductor manufacturing, biomedicine, and cleanroom engineering. Currently, existing aerosol generators generally have significant drawbacks, making it difficult to meet the industry's demand for high precision and integrated applications. On the one hand, existing devices mostly adopt a single-function modular design, requiring multiple independent devices to be combined for gas source preparation, aerosol generation, particle size classification, and airflow mixing. This not only results in large equipment footprints and complex pipeline connections but also easily leads to aerosol concentration fluctuations and increased particle agglomeration due to poor sealing at the joints of multiple devices and unstable airflow, thus affecting calibration accuracy. On the other hand, for large-particle-size aerosols of 1-10μm, existing atomization devices mostly use small, general-purpose atomization structures and lack dedicated large-particle-size atomization designs. During atomization, problems such as particle sedimentation and uneven breakage are prone to occur, and a large number of tiny impurities are easily mixed into the atomized aerosol, resulting in poor monodispersity and the inability to form a stable and controllable standard particle stream. Meanwhile, existing technologies lack integrated aerosol generators that can handle a wide particle size range (0.1μm-10μm). Obtaining aerosols with different particle size ranges requires replacing different types of atomizing equipment, resulting in cumbersome operation, low switching efficiency, and high equipment investment costs. Furthermore, while some integrated devices attempt to integrate multiple functions, they haven't optimized pipeline design for the delivery characteristics of large-particle-size aerosols. Numerous bends and unreasonable pipeline layouts further exacerbate the gravitational settling losses of large-particle-size particles, leading to unstable aerosol concentration and uneven particle size distribution at the outlet. This fails to meet the stringent requirements for standard particle stability and consistency during particle counter calibration. Consequently, most particle counter calibration institutions in China currently lack suitable and stable wide-particle-size aerosol generation systems, limiting the promotion and upgrading of particle counter calibration technology. Therefore, developing a highly integrated device that can stably output standard aerosols across a wide particle size range and address the pain points of large-particle-size aerosol generation has become a pressing technical challenge for the industry. Summary of the Invention

[0003] This invention addresses the technical problem of wet aerosol generators struggling to produce uniform and stable large-particle aerosols. It proposes a wide-particle-range standard particle generator that integrates gas source preparation, aerosol generation, classification, and mixing, producing large-particle aerosols with good monodispersity and high stability and consistency of aerosol concentration.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a standard particle generating device with a wide particle size range, comprising an aerosol generating unit and an aerosol processing unit. The aerosol generating unit includes a first aerosol atomizer and a second aerosol atomizer. The aerosol processing unit includes a first mixing chamber, a heating mixing chamber, a virtual cutter, and a mixer connected sequentially from top to bottom. An electrostatic neutralizer is installed at the upper end of the first mixing chamber. A conical cavity is provided inside the virtual cutter, and an accelerating nozzle is provided at the bottom of the conical cavity. A receiving tube is provided below the conical cavity. A cutter exhaust port is connected to the lower part of the virtual cutter. The cutter exhaust port is connected sequentially to a second drying cylinder, a fourth high-efficiency filter, a flow meter, and a micro negative pressure air pump via pipelines. The micro negative pressure air pump generates a strong airflow to discharge small particles from the virtual cutter. A supplementary air filter is connected to the upper part of the mixer. A static mixer is installed inside the mixer. Two or more aerosol outlet connectors are provided at the lower end of the mixer.

[0005] Preferably, the system also includes a clean air supply unit, which comprises a first high-efficiency filter, a micro positive pressure air pump, an air tank, a first drying cylinder, a mass flow meter, and a three-way solenoid valve connected in sequence via pipelines. The second and third ports of the three-way solenoid valve are respectively connected to the air inlet of the first aerosol atomizer and the second aerosol atomizer.

[0006] Preferably, a pressure transmitter is connected between the mass flow meter and the first drying cylinder.

[0007] Preferably, both the first aerosol atomizer and the second aerosol atomizer are connected to a high-efficiency filter at their front ends.

[0008] Preferably, the first aerosol atomizer produces aerosols with a particle size of 0.1 μm-1 μm, and the second aerosol atomizer produces aerosols with a particle size of 1 μm-10 μm.

[0009] Preferably, the outer wall of the heating and mixing chamber is equipped with a temperature sensor and covered with a heating belt and an insulation layer.

[0010] Preferably, the cutter's air extraction nozzle is also connected to a water reservoir and a peristaltic pump to periodically drain condensate.

[0011] Preferably, the static mixer is a double helix plate.

[0012] Preferably, the second aerosol atomizer includes a main chamber, an aerosol outlet is provided at the upper part of the main chamber, a main chamber fixing seat is installed at the lower part of the main chamber, a high-speed airflow nozzle and an aerosol nozzle are provided in the main chamber and fixed on the main chamber fixing seat, and a quick connector is connected below the main chamber fixing seat.

[0013] Preferably, the upper end of the heating and mixing chamber is connected to the first mixing chamber via a support flange on the heating tube, and the lower end of the heating and mixing chamber is connected to the virtual cutter via a lower support flange on the heating tube, a heat insulation support flange, and a cutter connecting flange.

[0014] Compared with the prior art, the advantages and positive effects of the present invention are as follows: The standard particle generating device with a wide particle size range of the present invention integrates gas source preparation, aerosol generation, classification and mixing into one unit, with a high degree of integration. It adopts two types of aerosol atomizers, and innovatively adopts a large particle generator, which has high atomization efficiency and can output a considerable number of large-particle aerosols. It can be easily switched and outputs aerosols with a particle size range of 0.1μm-10μm.

[0015] The heating and conveying pipelines of the aerosol processing unit are mainly arranged vertically with few bends. This structural design can significantly enhance the conveying efficiency of large particle aerosols, effectively reduce particle loss due to gravity settling, and ultimately ensure that the concentration of large particle aerosols remains stable and the output performance remains consistent.

[0016] The aerosol processing unit applies a virtual cutter to aerosol particle size classification, which can reduce background residual particles and improve monodispersity. The mixer can achieve good aerosol mixing without a large space, and the mixer has multiple sampling ports arranged in a reasonable manner to ensure the consistency of aerosol concentration and particle size distribution. Attached Figure Description

[0017] Figure 1 is a system schematic diagram of the wide particle size range standard particle generator of the present invention; Figure 2 is a pipeline connection schematic diagram of the wide particle size range standard particle generator of the present invention; Figure 3 is a structural schematic diagram of the second aerosol atomizer of the wide particle size range standard particle generator of the present invention; Figure 4 is a structural schematic diagram of the aerosol generation unit and aerosol processing unit of the wide particle size range standard particle generator of the present invention; Figure 5 is a structural schematic diagram of the double helix plate of the wide particle size range standard particle generator of the present invention; In the above figures: 1, clean gas supply unit; 2, aerosol generation unit; 3. Aerosol processing unit; 4. Reference instrument; 5. Instrument under calibration; 6. Control unit; 7. First high-efficiency filter; 8. Miniature positive pressure air pump; 9. Gas tank; 10. First drying cylinder; 11. Pressure transmitter; 12. Mass flow meter; 13. Three-way solenoid valve; 14. Second high-efficiency filter; 15. Third high-efficiency filter; 16. First aerosol atomizer; 17. Second aerosol atomizer; 18. First make-up high-efficiency filter; 19. First high-efficiency mounting base; 20. Second make-up high-efficiency filter; 21. Second high-efficiency mounting base; 22. Peristaltic pump; 23. Water tank; 24. Second drying cylinder; 25. Fourth high-efficiency filter; 26. Flow meter; 27. Miniature negative pressure air pump; 28. Adapter tee; 29. ​​Pressure sensor; 30. Adapter 2; 31. Reference standard instrument; 32. Instrument under calibration; 33. First generator connector; 34. Electrostatic neutralizer; 35. First mixing chamber; 36. Second generator connector; 37. Support flange on heating tube; 38. Heating mixing chamber; 39. Fiberglass heating strip; 40. Insulation cotton; 41. Temperature sensor; 42. 43. Heating tube lower support flange; 44. Insulation support flange; 45. Cutter connection flange; 46. Virtual cutter upper end; 47. Virtual cutter lower end; 48. Mixer; 49. High-efficiency air supply nozzle; 50. Static mixer; 51. Aerosol dual outlet seat; 52. Aerosol outlet connector; 53. Cutter air extraction nozzle; 54. Insulation ring; 55. Quick-connect connector; 56. Main chamber fixing seat; 57. High-speed airflow nozzle; 58. Aerosol nozzle; 59. Main chamber; 60. Conical cavity; 61. Acceleration nozzle; 62. Receiving tube. Detailed Implementation

[0018] To better understand the present invention, the following detailed description is provided in conjunction with the accompanying drawings and embodiments.

[0019] Example: As shown in Figures 1 and 2, a standard particle generator with a wide particle size range includes a clean gas supply unit 1, an aerosol generation unit 2, an aerosol processing unit 3, and a control unit 6. This device integrates gas source preparation, aerosol generation, aerosol classification, and mixing functions, and can output aerosols with particle sizes in the range of 0.1μm-10μm.

[0020] The clean gas supply unit 1 includes a miniature positive pressure air pump 8 for providing a gas source. The air inlet of the miniature positive pressure air pump 8 is connected to the first high-efficiency filter 7, and its air outlet is connected in sequence to the gas tank 9, the first drying cylinder 10, the mass flow meter 12 and the three-way solenoid valve 13 via pipelines. A pressure transmitter 11 is also connected between the first drying cylinder 10 and the mass flow meter 12.

[0021] The aerosol generating unit 2 includes a first aerosol atomizer 16 and a second aerosol atomizer 17. The first aerosol atomizer 16 is used to generate aerosols with a particle size of 0.1-1μm. Its specific structure can be a small aerosol atomizer commonly used in the prior art. In this embodiment, an independently developed aerosol atomizer is used, the specific structure of which is the subject of invention patent application number 2020110907947. The second port of the three-way solenoid valve 13 is connected to the second high-efficiency filter 14. The outlet of the second high-efficiency filter 14 is connected to the inlet of the first aerosol atomizer 16 to provide clean gas to the first aerosol atomizer 16. A first generator connection seat 33 is provided between the first aerosol atomizer 16 and the aerosol processing unit 3.

[0022] As shown in Figure 3, the second aerosol atomizer 17 is used to generate aerosols with a particle size of 1-10 μm. Its structure includes a main chamber 58, with an aerosol outlet at the top and a main chamber mounting base 55 at the bottom. A high-speed airflow nozzle 56 and an aerosol nozzle 57 are fixed to the main chamber mounting base 55 within the main chamber 58. A quick-connect connector 54 is connected below the main chamber mounting base 55. A second generator connection base 36 is provided between the second aerosol atomizer 17 and the aerosol processing unit 3. The third port of the three-way solenoid valve 13 is connected to a third high-efficiency filter 15, and the outlet of the third high-efficiency filter 15 is connected to the quick-connect connector 54 to provide clean gas to the second aerosol atomizer 17. Clean gas enters the atomizer through the quick-connect connector 54 and forms a high-speed airflow under the action of the high-speed airflow nozzle 56. This creates a negative pressure inside the aerosol nozzle 57, drawing in the solution and forming broken droplets. Carried by the high-speed airflow, the droplets further impact the top of the main chamber 58 and are broken into even smaller droplets, thus facilitating the delivery of the aerosol. Driven by the airflow below, the aerosol enters the aerosol processing unit 3 from the left end of the main chamber 58.

[0023] As shown in Figures 4 and 5, the aerosol treatment unit 3 includes an electrostatic neutralizer 34, a heating and mixing chamber 38, a virtual cutter, and a mixer 47. These four components are arranged vertically from top to bottom and connected by flanges. The connections are sealed with O-rings, forming a sealed vertical aerosol flow path. Specifically, the electrostatic neutralizer 34 is fixed above the first mixing chamber 35. The lower end of the first mixing chamber 35 is connected and fixed to the heating and mixing chamber 38 via a supporting flange 37 on the heating pipe and a heat insulation ring 53.

[0024] The upper end of the heating and mixing chamber 38 is connected to the first mixing chamber 35 via a supporting flange 37 on the heating tube. The lower end of the heating and mixing chamber 38 is connected to the virtual cutter via a lower supporting flange 42 on the heating tube, a heat-insulating supporting flange 43, and a cutter connecting flange 44. The heat-insulating supporting flange 43 effectively isolates heat, preventing the temperature inside the cutter from rising. A fiberglass heating strip 39 is wrapped around the outside of the heating and mixing chamber 38. A temperature sensor 41 is installed inside the fiberglass heating strip 39, and insulation cotton 40 is wrapped around the outer layer of the fiberglass heating strip 39, thereby precisely controlling the heating temperature inside the heating and mixing chamber 38 and maintaining a constant temperature.

[0025] The virtual cutter consists of two parts: an upper part 45 and a lower part 46, which are connected by a flange. The virtual cutter contains a conical cavity 59, with an accelerating nozzle 60 at the bottom and a receiving pipe 61 below it. The accelerating nozzle 60 has a diameter of 2mm, the receiving pipe 61 has a diameter of 2.6mm, and the distance between them is 2mm. The ratio of strong to weak airflow is set to 10:1.

[0026] The lower end 46 of the virtual cutter is equipped with a cutter exhaust nozzle 52. The cutter exhaust nozzle 52 is connected in sequence via pipeline to a second drying cylinder 24, a fourth high-efficiency filter 25, a flow meter 26, and a miniature negative pressure air pump 27. The flow meter 26 is connected to a pressure sensor 29 via a two-way adapter 30, and a three-way adapter 28 can be installed in the pipeline. The miniature negative pressure air pump 27 provides negative pressure to the virtual cutter. The aerosol heated by the heating and mixing chamber 38 enters the conical cavity 59. Small particles in the aerosol enter the space surrounding the receiving tube 61 under the action of strong airflow and are discharged from the virtual cutter through the cutter exhaust nozzle 52, reducing background residual particulate matter and improving monodispersity. The cutter exhaust nozzle 52 is also connected to a water reservoir 23 and a peristaltic pump 22 to periodically discharge the condensate generated in the virtual cutter.

[0027] The mixer 47 has two high-efficiency air supply nozzles 48 on its upper part. The two high-efficiency air supply nozzles 48 are respectively connected to the first high-efficiency fixing seat 19 and the second high-efficiency fixing seat 21. The first high-efficiency air supply filter 18 is installed on the first high-efficiency fixing seat 19, and the second high-efficiency air supply filter 20 is installed on the second high-efficiency fixing seat 21. A static mixer 49 is provided inside the mixer 47. The static mixer 49 has a double-helix plate structure, which can make the aerosol rotate and flow, avoiding sedimentation.

[0028] The lower end of the mixer 47 is an aerosol dual-outlet seat 50, on which two aerosol outlet connectors 51 are installed, which can be connected to the reference standard instrument 31 and the calibrated instrument 32 respectively. The reference standard instrument 31 is the reference instrument 4, and the calibrated instrument 32 is the calibrated instrument 5.

[0029] The control unit 6 is electrically connected to the miniature positive pressure air pump 8, mass flow meter 12, three-way solenoid valve 13, miniature negative pressure air pump 27, peristaltic pump 22, and temperature sensor 41, respectively, to control the coordinated operation of each component. The operation process of the wide particle size range standard particle generator described in this embodiment is as follows: Under the action of the miniature positive pressure air pump 8, the airflow is coarsely filtered by the first high-efficiency filter 7, and the air path is stabilized by the air tank 9. The first drying cylinder 10 removes water vapor from the gas to protect the downstream electrical components. Subsequently, the pressure transmitter 11 and mass flow meter 12 further ensure the stability of the generated gas pressure and flow rate. The clean gas is selectively filtered again by the second high-efficiency filter 14 or the third high-efficiency filter 15 through the three-way solenoid valve 13 to form clean gas. The user selects a suitable aerosol atomizer according to the particle size requirements. When it is necessary to generate aerosols smaller than 1μm, the clean gas can be controlled to enter the first aerosol atomizer 16; when it is necessary to generate large particle aerosols larger than 1μm, the clean gas can be controlled to enter the second aerosol atomizer 17.

[0030] After entering the aerosol treatment unit 3, the electrostatic charge carried by the aerosol particles is eliminated by the electrostatic neutralizer 34. Then, it enters the heating and mixing chamber 38. The high temperature in the heating and mixing chamber 38 removes the moisture on the surface of the particles, so that the particles are separated from the water and enter the virtual cutter.

[0031] Considering that the standard material contains surfactants and other components, and that the microspheres may rupture during the formation process, experiments have shown that aerosols with a particle size of 3μm and above will contain a large number of tiny impurities, affecting their monodispersity. Therefore, this invention incorporates a 2μm virtual cutter. When only aerosols of 3μm and above are generated, a miniature negative pressure air pump 27 is activated. Tiny impurities smaller than 2μm are carried by a strong airflow and discharged after being processed by the second drying cylinder 24 and the fourth high-efficiency filter 25. Only a small amount of airflow carrying high-inertia large particles passes through the receiving tube for mixing.

[0032] The aerosol with good monodispersity enters the mixer 47 for homogenization. It is equipped with a first high-efficiency air supply filter 18 and a second high-efficiency air supply filter 20 for passive air supply to meet different flow requirements. The static mixer 49 built into the mixer 47 can generate a strong swirling flow along the central axis of the pipeline and generate a strong shear force on the fluid. This can not only greatly enhance the gas-solid mixing effect, but also effectively improve the uniformity of the aerosol at the aerosol outlet. Finally, the homogenized aerosol enters the instrument through the aerosol outlet connector 51.

[0033] This wide-particle-size standard particle generator integrates gas source preparation, aerosol generation, classification, and mixing into one highly integrated unit. It employs two types of aerosol atomizers, and innovatively uses a large-particle generator, which has high atomization efficiency and can output a considerable number of large-particle aerosols. It can be easily switched and outputs aerosols with a particle size range of 0.1μm-10μm.

[0034] The heating and conveying pipelines of the aerosol processing unit 3 are mainly arranged vertically, and the number of bends in the pipelines is small. This structural design can significantly enhance the conveying efficiency of large particle aerosols, effectively reduce the loss of particles due to gravity settling, and ultimately ensure that the concentration of large particle aerosols remains stable and the output performance remains consistent.

[0035] The aerosol processing unit 3 applies a virtual cutter to aerosol particle size classification, which can reduce background residual particles and improve monodispersity. The mixer 47 can achieve good mixing of aerosols without a large space, and the mixer 47 has multiple sampling ports arranged in a reasonable manner to ensure the consistency of aerosol concentration and particle size distribution.

[0036] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments for application in other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A standard particle generator with a wide particle size range, characterized in that: The system includes an aerosol generation unit and an aerosol processing unit. The aerosol generation unit includes a first aerosol atomizer and a second aerosol atomizer. The aerosol processing unit includes, from top to bottom, a first mixing chamber, a heated mixing chamber, a virtual cutter, and a mixer. An electrostatic neutralizer is installed at the upper end of the first mixing chamber. The virtual cutter has a conical cavity with an accelerating nozzle at the bottom and a receiving tube below it. A cutter exhaust nozzle is connected to the lower part of the virtual cutter. The cutter exhaust nozzle is connected to a second drying cylinder, a fourth high-efficiency filter, a flow meter, and a miniature negative pressure air pump via pipelines. The miniature negative pressure air pump generates a strong airflow to expel small particles from the virtual cutter. A makeup air filter is connected to the upper part of the mixer, and a static mixer is installed inside the mixer. Two or more aerosol outlet connectors are provided at the lower end of the mixer.

2. The standard particle generating device with a wide particle size range according to claim 1, characterized in that: It also includes a clean air supply unit, which includes a first high-efficiency filter, a micro positive pressure air pump, an air tank, a first drying cylinder, a mass flow meter and a three-way solenoid valve connected in sequence via pipelines. The second and third ports of the three-way solenoid valve are respectively connected to the air inlet of the first aerosol atomizer and the second aerosol atomizer.

3. The wide particle size range standard particle generating device according to claim 2, characterized in that: A pressure transmitter is connected between the mass flow meter and the first drying cylinder.

4. The standard particle generating device with a wide particle size range according to claim 1, characterized in that: Both the first aerosol atomizer and the second aerosol atomizer are connected to a high-efficiency filter at their front end.

5. The standard particle generating device with a wide particle size range according to claim 1, characterized in that: The first aerosol atomizer produces aerosols with a particle size of 0.1μm-1μm, and the second aerosol atomizer produces aerosols with a particle size of 1μm-10μm.

6. The standard particle generating device with a wide particle size range according to claim 1, characterized in that: The outer wall of the heating and mixing chamber is equipped with a temperature sensor and is covered with a heating belt and an insulation layer.

7. The standard particle generating device with a wide particle size range according to claim 1, characterized in that: The cutter's air extraction nozzle is also connected to a water reservoir and a peristaltic pump to periodically drain condensate.

8. The standard particle generator with a wide particle size range according to claim 1, characterized in that: The static mixer is a double-helix plate.

9. The standard particle generator with a wide particle size range according to claim 1, characterized in that: The second aerosol atomizer includes a main chamber, an aerosol outlet at the upper part of the main chamber, a main chamber mounting base at the lower part of the main chamber, a high-speed airflow nozzle and an aerosol nozzle fixed on the main chamber mounting base inside the main chamber, and a quick-connect connector connected below the main chamber mounting base.

10. The standard particle generating device with a wide particle size range according to claim 1, characterized in that: The upper end of the heating and mixing chamber is connected to the first mixing chamber through the upper support flange of the heating tube, and the lower end of the heating and mixing chamber is connected to the virtual cutter through the lower support flange of the heating tube, the heat insulation support flange and the cutter connecting flange.

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