Sub-micron particle sorting secondary virtual impactor

Abstract

This application discloses a two-stage virtual impactor for sorting submicron particles, belonging to the field of aerosol separation. The virtual impactor includes a housing and a first-stage and a second-stage virtual impactor disposed within the housing. Both the first-stage and second-stage virtual impactors are arranged parallel to each other along the length of the housing. A deflection channel is also provided within the housing. One outlet of the first-stage virtual impactor is connected to the inlet of the second-stage virtual impactor through the deflection channel. This virtual impactor, through staged processing, optimizes design parameters for each stage within a specific particle size range, resulting in a more uniform particle group and reducing the probability of non-target impacts on the wall due to mixing. This design systematically reduces particle losses caused by inertial impaction, turbulent entrainment, and other mechanisms, enabling it to better adapt to low-concentration, high-precision particle separation, significantly improving separation efficiency and data reliability.

Description

Technical Field

[0001] This application relates to the field of aerosol separation technology, specifically a submicron-level particle sorting two-stage virtual impactor. Background Technology

[0002] The importance of detecting battery leaks in new energy vehicles cannot be ignored, as it directly relates to public safety, property security, and the sustainable and healthy development of the economy. In terms of safety, battery leaks can lead to fires or explosions, posing a serious threat to life and property. Common methods for detecting battery leaks in new energy vehicles include gas detection, electrolyte detection, voltage monitoring, temperature monitoring, insulation resistance testing, visual inspection, ultrasonic testing, infrared thermal imaging, leak detection sensors, and intelligent monitoring systems.

[0003] Research has found that lithium batteries release a large amount of particulate matter in the initial stage of combustion or explosion. These particles can be mainly divided into three parts: positive electrode material particles (40%-50%), including metal oxides and lithium salt particles; negative electrode material particles (20%-30%), mainly composed of graphite or carbon-silicon composite carbon-based particles; and electrolyte decomposition products (15%-25%), including fluorine- and sulfur-containing particles, which are corrosive and toxic.

[0004] In existing technology, when conducting separation experiments, the virtual impactor uses a collecting nozzle instead of the impact plate of the inertial impactor, avoiding the problems of particle rebound and secondary entrainment in traditional impactors. The airflow containing particles is accelerated by the nozzle to form a high-speed jet, which splits into two streams at a specific location: the main stream and the secondary stream. Large particles have greater inertia and are difficult to change direction with the airflow, so they directly pass through the airflow boundary line into the secondary stream and are then separated. Small particles have less inertia and move in the direction of the main stream, bypassing the separation zone to achieve enrichment.

[0005] However, when targeting particles with a diameter of submicron (10-200nm), existing virtual impactors have the following shortcomings: low separation efficiency: traditional single-stage impactors have a separation rate of less than 50% for submicron particles (<1μm), which is difficult to meet the high-precision detection requirements of LiF particles in the early stage of lithium battery combustion and explosion.

[0006] Therefore, this application provides a submicron-level particle sorting two-stage virtual impactor to solve the above problems. Utility Model Content

[0007] This application provides a two-stage virtual impactor for sorting submicron particles, which aims to solve the problems mentioned in the background art, such as the difficulty of existing virtual impactors in separating submicron particles.

[0008] To achieve the above objectives, this application provides the following technical solution: a submicron-level particle sorting two-stage virtual impactor, comprising a housing and a first-stage virtual impactor and a second-stage virtual impactor disposed within the housing:

[0009] Both the first-stage virtual impactor and the second-stage virtual impactor are arranged along the length of the shell and are parallel to each other.

[0010] The housing also includes a deflection channel, through which the outlet of the first-stage virtual impactor is connected to the inlet of the second-stage virtual impactor. In this way, during use, through graded processing, the first-stage virtual impactor separates particles larger than one micrometer, while the second-stage virtual impactor processes smaller particles. Each stage optimizes design parameters for a specific particle size range, resulting in a more uniform particle group and reducing the probability of non-target impacts on the wall due to mixing. This design systematically reduces particle losses caused by inertial impaction, turbulent entrainment, and other mechanisms, enabling it to better adapt to low-concentration, high-precision particle separation, significantly improving separation efficiency and data reliability.

[0011] Preferably, for initial screening, the first-stage virtual impactor includes an inlet on the housing, a first threaded air inlet pipe fixedly installed at the inlet inside the housing, a first-stage main flow channel fixedly installed on the first threaded air inlet pipe and connected thereto, the first-stage main flow channel being symmetrically distributed in a U-shape on both sides of the first threaded air inlet pipe, and a first-stage secondary flow channel fixedly installed at the center of the first-stage main flow channel and connected to the first threaded air inlet pipe, thereby achieving initial screening of large particles, and submicron / nano particles entering the first-stage main flow channel with the deflected airflow to complete the diversion.

[0012] Preferably, for material discharge, the first-stage secondary flow channel and the first-stage primary flow channel are located on the same horizontal plane. The first-stage secondary flow channel has a continuous U-shaped design. The end of the first-stage secondary flow channel away from the first threaded air inlet pipe extends to the outer wall of the shell and a first waste outlet is opened on the outer wall of the shell to avoid rigid stretching or rupture of the pipe, and finally discharge through the first waste outlet.

[0013] Preferably, in order to connect the flow channel, the diverting flow channel is U-shaped and arranged in the same direction as the first-stage main flow channel. The end of the diverting flow channel is connected to the two ends of the first-stage main flow channel away from the first threaded air inlet pipe, so that the mixed gas can be finely sieved.

[0014] Preferably, for fine screening, the second-stage virtual impactor includes a second threaded air inlet pipe fixedly installed in the middle of the turning flow channel and connected to the turning flow channel. A second-stage main flow channel is fixedly installed and connected to the second threaded air inlet pipe at one end away from the turning flow channel. The second-stage main flow channels are symmetrically distributed in a U-shape on both sides of the second threaded air inlet pipe. A second-stage secondary flow channel is fixedly installed and connected to the second threaded air inlet pipe at the center of the second-stage main flow channel, thereby effectively improving the separation efficiency and meeting the high-precision detection requirements of LiF particles in the early stage of lithium battery combustion and explosion.

[0015] Preferably, in order to collect gas, the second-stage main flow channel and the second-stage secondary flow channel are set on different horizontal planes. The two ends of the second-stage main flow channel extend towards the bottom of the shell and converge at the end away from the second threaded air inlet pipe to form a closed annular tube design. An outlet that penetrates the shell is fixedly installed at the end of the second-stage main flow channel away from the second threaded air inlet pipe, and the gas is finally collected and discharged through the outlet to improve the collection efficiency.

[0016] Preferably, for exhaust purposes, the second-stage secondary flow channel has a continuous U-shaped design. The end of the second-stage secondary flow channel away from the second threaded intake pipe extends to the outer wall of the housing and has a second waste outlet on the outer wall of the housing. The exhaust is finally discharged through the second waste outlet, thereby improving the exhaust efficiency.

[0017] This virtual impactor uses a tiered process. The first-stage virtual impactor separates particles larger than 1 micrometer, while the second-stage virtual impactor processes smaller particles. Each stage optimizes design parameters for a specific particle size range, resulting in a more uniform particle group and reducing the probability of non-target impacts on the wall due to mixing. This design systematically reduces particle losses caused by inertial impacts, turbulent entrainment, and other mechanisms, enabling it to better adapt to low-concentration, high-precision particle separation and significantly improving separation efficiency and data reliability.

[0018] This virtual impactor allows airflow to travel along a serpentine channel, enhancing fluid transport efficiency, reducing losses from small particles and airflow leakage, and absorbing overall expansion through the synergistic deformation of multiple folds, thus preventing rigid stretching or rupture of the pipe. Attached Figure Description

[0019] Figure 1 A schematic diagram of the external structure of a two-stage virtual impactor for sorting submicron particles;

[0020] Figure 2 A schematic diagram of the bottom structure of a two-stage virtual impactor for sorting submicron particles;

[0021] Figure 3 A schematic diagram of the side structure of a two-stage virtual impactor for sorting submicron particles;

[0022] Figure 4 A schematic diagram of the internal structure of a submicron-level particle sorting two-stage virtual impactor;

[0023] Figure 5 This is a schematic diagram of the internal structure of a submicron particle sorting two-stage virtual impactor.

[0024] In the picture:

[0025] 1. Shell; 2. First-stage virtual impactor; 21. Inlet; 22. First threaded air inlet pipe; 23. First-stage main flow channel; 24. First-stage secondary flow channel; 25. First waste outlet; 3. Second-stage virtual impactor; 31. Second threaded air inlet pipe; 32. Second-stage main flow channel; 33. Second-stage secondary flow channel; 34. Outlet; 35. Second waste outlet; 4. Diverting flow channel. Detailed Implementation

[0026] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] Example 1

[0028] This embodiment provides a submicron-level particle sorting two-stage virtual impactor, such as... Figures 1-5 As shown, the virtual impactor includes a housing 1 and a first-stage virtual impactor 2 and a second-stage virtual impactor 3 disposed within the housing 1.

[0029] The first-stage virtual impactor 2 and the second-stage virtual impactor 3 are both arranged along the length of the shell 1 and are parallel to each other.

[0030] The housing 1 is also provided with a turning channel 4, and one of the air outlets of the first-stage virtual impactor 2 is connected to the air inlet of the second-stage virtual impactor 3 through the turning channel 4.

[0031] In use, through graded processing, the first-stage virtual impactor 2 separates particles with a diameter of 1 micrometer or larger, and the second-stage virtual impactor 3 processes smaller particles. Each stage optimizes design parameters for a specific particle size range, making the particle group more uniform and reducing the probability of non-target impacts on the wall due to mixing. This design systematically reduces particle losses caused by inertial impacts, turbulent entrainment and other mechanisms, making it better suited for low-concentration, high-precision particle separation, and significantly improving separation efficiency and data reliability.

[0032] Specifically, the first-stage virtual impactor 2 includes an inlet 21 opened on the housing 1. A first threaded air inlet pipe 22 is fixedly installed inside the housing 1 at the inlet 21. A first-stage main flow channel 23 is fixedly installed on the first threaded air inlet pipe 22 and is connected to it. The first-stage main flow channel 23 is symmetrically distributed in a U-shape on both sides of the first threaded air inlet pipe 22. A first-stage secondary flow channel 24 connected to the first threaded air inlet pipe 22 is fixedly installed at the center of the first-stage main flow channel 23.

[0033] In use, the airflow is pre-distributed through the first threaded inlet pipe 22 and then enters the first-stage virtual impactor 2. Large particles >1μm are separated from the streamline due to their high Stokes number Stk>1. After being captured, they are discharged from the system through the first-stage secondary flow channel 24, thus achieving the initial screening of large particles. Submicron / nano particles enter the first-stage main flow channel 23 with the deflected airflow, completing the diversion.

[0034] More specifically, the first-level secondary flow channel 24 and the first-level primary flow channel 23 are located on the same horizontal plane. The first-level secondary flow channel 24 has a continuous U-shaped design. One end of the first-level secondary flow channel 24 away from the first threaded air inlet pipe 22 extends to the outer wall of the housing 1 and a first waste outlet 25 is opened on the outer wall of the housing 1.

[0035] In use, large particles are captured and transported along a serpentine flow path through the first-stage secondary flow channel 24, which enhances fluid transport efficiency, reduces the loss of small particles and airflow, absorbs the overall expansion through the synergistic deformation of multiple folds, avoids rigid stretching or rupture of the pipeline, and is finally discharged through the first waste outlet 25.

[0036] Furthermore, the steering channel 4 is U-shaped and positioned in the same direction as the first-stage main flow channel 23, and the end of the steering channel 4 is connected to the two ends of the first-stage main flow channel 23 that are away from the first threaded air inlet pipe 22.

[0037] In use, submicron / nano particles are carried by the deflected airflow into the turning channel 4, where they are mixed with the airflow in the first-stage secondary flow channel 24 and then transported to the second-stage virtual impactor 3 for fine sieving.

[0038] Example 2

[0039] The second-stage virtual impactor 3 includes a second threaded air inlet pipe 31 fixedly installed in the middle of the turning flow channel 4 and connected to the turning flow channel 4. A second-stage main flow channel 32 is fixedly installed at the end of the second threaded air inlet pipe 31 away from the turning flow channel 4 and is connected to it. The second-stage main flow channel 32 is symmetrically distributed in a U-shape on both sides of the second threaded air inlet pipe 31. A second-stage secondary flow channel 33 is fixedly installed at the center of the second-stage main flow channel 32 and is connected to the second threaded air inlet pipe 31.

[0040] In use, the airflow carrying small particles enters the second threaded air inlet pipe 31 through the deflection channel 4. Target particles, such as 200 nm LiF, migrate away from the streamline due to the critical inertia Stk≈0.6 and are enriched in the second-stage secondary flow channel 33. Non-target particles are discharged through the second-stage main flow channel 32, completing secondary fine separation, thereby effectively improving the separation efficiency and meeting the high-precision detection requirements of LiF particles in the early stage of lithium battery combustion and explosion.

[0041] Specifically, the second-stage main flow channel 32 and the second-stage secondary flow channel 33 are set on different horizontal planes. The two ends of the second-stage main flow channel 32 extend toward the bottom of the housing 1 and converge at the end away from the second threaded air inlet pipe 31 to form a closed annular tube design. An outlet 34 that penetrates the housing 1 is fixedly installed at the end of the second-stage main flow channel 32 away from the second threaded air inlet pipe 31.

[0042] In use, the layered structure provides more space for gas flow. The second-stage main flow channel 32 collects non-target particles and gas from both sides by adapting to the airflow path, and finally discharges them through the outlet 34, thus improving collection efficiency.

[0043] More specifically, the second-stage secondary flow channel 33 has a continuous U-shaped design, and one end of the second-stage secondary flow channel 33 away from the second threaded air inlet pipe 31 extends to the outer wall of the housing 1 and a second waste outlet 35 is provided on the outer wall of the housing 1.

[0044] In use, after the target particles are captured, they are transported along the serpentine flow path through the second-stage secondary flow channel 33, which enhances the fluid transport efficiency. The overall expansion is absorbed by the synergistic deformation of multiple folds, avoiding rigid stretching or rupture of the pipeline, and finally discharged through the second waste outlet 35, thus improving the discharge efficiency.

[0045] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in this application, based on the technical solution and concept of this application, should be included within the scope of protection of this application.

Claims

1. A two-stage virtual impactor for sorting submicron particles, comprising a housing (1) and a first-stage virtual impactor (2) and a second-stage virtual impactor (3) disposed within the housing (1), characterized in that: The first-stage virtual impactor (2) and the second-stage virtual impactor (3) are both arranged along the length of the shell (1) and are parallel to each other; The housing (1) is also provided with a turning channel (4), and one of the air outlets of the first-stage virtual impactor (2) is connected to the air inlet of the second-stage virtual impactor (3) through the turning channel (4).

2. The submicron-level particle sorting two-stage virtual impactor according to claim 1, characterized in that: The first-stage virtual impactor (2) includes an inlet (21) opened on the housing (1). A first threaded air inlet pipe (22) is fixedly installed in the housing (1) at the inlet (21). A first-stage main flow channel (23) is fixedly installed on the first threaded air inlet pipe (22) and is connected to it. The first-stage main flow channel (23) is symmetrically distributed in a U-shape on both sides of the first threaded air inlet pipe (22). A first-stage secondary flow channel (24) connected to the first threaded air inlet pipe (22) is fixedly installed at the center of the first-stage main flow channel (23).

3. The submicron-level particle sorting two-stage virtual impactor according to claim 2, characterized in that: The first-stage secondary flow channel (24) and the first-stage primary flow channel (23) are located on the same horizontal plane. The first-stage secondary flow channel (24) has a continuous U-shaped design. The end of the first-stage secondary flow channel (24) away from the first threaded air inlet pipe (22) extends to the outer wall of the housing (1) and a first waste outlet (25) is opened on the outer wall of the housing (1).

4. The submicron-level particle sorting two-stage virtual impactor according to claim 1, characterized in that: The turning channel (4) is U-shaped and is positioned in the same direction as the first-stage main flow channel (23). The end of the turning channel (4) is connected to the two ends of the first-stage main flow channel (23) that are away from the first threaded air inlet pipe (22).

5. The submicron-level particle sorting two-stage virtual impactor according to claim 1, characterized in that: The second-stage virtual impactor (3) includes a second threaded air inlet pipe (31) fixedly installed in the middle of the turning flow channel (4) and connected to the turning flow channel (4). A second-stage main flow channel (32) is fixedly installed at one end of the second threaded air inlet pipe (31) away from the turning flow channel (4). The second-stage main flow channel (32) is symmetrically distributed in a U-shape on both sides of the second threaded air inlet pipe (31). A second-stage secondary flow channel (33) is fixedly installed at the center of the second-stage main flow channel (32) and connected to the second threaded air inlet pipe (31).

6. The submicron-level particle sorting two-stage virtual impactor according to claim 5, characterized in that: The second-stage main flow channel (32) and the second-stage secondary flow channel (33) are set on different horizontal planes. The two ends of the second-stage main flow channel (32) extend toward the bottom of the housing (1) and converge at the end away from the second threaded air inlet pipe (31) to form a closed annular tube design. An outlet (34) that penetrates the housing (1) is fixedly installed at the end of the second-stage main flow channel (32) away from the second threaded air inlet pipe (31).

7. The submicron-level particle sorting two-stage virtual impactor according to claim 5, characterized in that: The second-stage secondary flow channel (33) has a continuous U-shaped design. One end of the second-stage secondary flow channel (33) away from the second threaded air inlet pipe (31) extends to the outer wall of the housing (1) and a second waste outlet (35) is provided on the outer wall of the housing (1).

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