CN118824835B - Injection device and mass spectrometer for broadening the particle size transmission range of aerodynamic lens - Google Patents
Injection device and mass spectrometer for broadening the particle size transmission range of aerodynamic lens Download PDFInfo
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- CN118824835B CN118824835B CN202411015331.2A CN202411015331A CN118824835B CN 118824835 B CN118824835 B CN 118824835B CN 202411015331 A CN202411015331 A CN 202411015331A CN 118824835 B CN118824835 B CN 118824835B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J49/00—Particle spectrometers or separator tubes
- H01J49/02—Details
- H01J49/04—Arrangements for introducing or extracting samples to be analysed, e.g. vacuum locks; Arrangements for external adjustment of electron- or ion-optical components
- H01J49/0422—Arrangements for introducing or extracting samples to be analysed, e.g. vacuum locks; Arrangements for external adjustment of electron- or ion-optical components for gaseous samples
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- H—ELECTRICITY
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Abstract
The application discloses a sample injection device and a mass spectrometer for widening the particle size transmission range of an aerodynamic lens, wherein the sample injection device comprises an aerosol conveying pipe, a first focusing piece and a critical orifice plate, wherein the first focusing orifice plate is fixedly arranged in the first focusing orifice, a second focusing orifice is formed in the focusing orifice plate and used for limiting particle distribution in an aerosol sample again, and the first focusing piece and the critical orifice plate are mutually matched to form a vortex cavity which is used for generating vortex so as to rectify the aerosol sample passing through the second focusing orifice. The vortex in the vortex cavity is used for rectifying the aerosol sample, so that the beam width of the aerosol sample can be effectively reduced, the transmission efficiency of the aerodynamic lens to large-diameter particles is improved, the particle transmission range of the aerodynamic lens can be effectively widened by using the sample injection device, the particle size detection range of the mass spectrometer is improved, more comprehensive data are obtained, and the behavior and effect of the particles can be better understood and explained.
Description
Technical Field
The invention relates to the technical field of mass spectrometry, in particular to a sample injection device and a mass spectrometer for widening the particle size transmission range of an aerodynamic lens.
Background
In the technical field of atmospheric environment detection, mass Spectrometry detection and analysis are a relatively common technical means for detecting and analyzing particulate matters in an air sample, wherein the most widely used technology is SPMS (SINGLE PARTICLE MASS Spectrometry ), which is used for analyzing chemical components and compositions of single particles in the atmosphere, and is generally used for researching sources, chemical characteristics and influences on environment and health of the atmospheric particulate matters. Mineral, sea salt and bioaerosols in the atmospheric environment are for the most part in coarse particle mode (particle size) Mainly limited by inertial wall collision loss of an SPMS (particle-free mass spectrometry) sample injection interface to coarse particlesThe particle detection capability is relatively limited, in particularThe above coarse particles. If a traditional sample injection interface is adopted, the sample injection interface is formed byThe above coarse particles are too large in loss to affect the final mass spectrum detection result, and the wide particle size range (particle size is) The application capability of SPMS in the aspects of bioaerosols, atmospheric particle source analysis, atmospheric aging mechanism and the like is limited.
The Chinese patent (application number: CN 201711079461.2) proposes a concentrating device and a pneumatic focusing system, wherein the concentrating device comprises a concentrating container, a sample injection mechanism, a flow guide mechanism and a buffer container, the concentrating container is provided with an air pressure cavity and an air extraction column, the sample injection mechanism is provided with a sample injection channel, a flow limiting hole and a flow dividing hole which are sequentially communicated, the flow guide mechanism is arranged on the concentrating container, and the buffer container is connected with the concentrating container and/or the flow guide mechanism and enables the buffer cavity to be communicated with the flow guide channel so as to meet the vacuum load requirement of the vacuum analysis equipment. When the concentration device is connected with the sample injection interface of the aerodynamic lens, under the condition of adopting conventional vacuum load, under the pushing of air pressure difference, the sample injection flow of the aerosol can be increased, the passing rate of large-particle-size particles can be increased, concentration of the aerosol and focusing of particle beams are realized, and the aerosol sample injection and detection work under low concentration can be facilitated.
Based on the above patent, chinese patent application No. CN202010615218.3 proposes an aerosol mass spectrum sample injection device with a wide particle size range and an aerosol mass spectrometer, a first aerosol focusing element and a first buffer tube are arranged in front of a critical orifice plate, and the first aerosol focusing element carries out prefocusing treatment on sample aerosol before entering the critical orifice plate, so that the loss caused by that larger particles in the sample aerosol collide with the critical orifice plate when passing through the central hole of the critical orifice plate can be avoided, the transmission performance of particles with the particle size of more than 1 mu m is improved, the particle size range of particles passing through the central hole of the critical orifice plate is enlarged, the detection of aerosol particles with the wide particle size range can be realized, in addition, the deposition and adhesion effects of large particles on the critical orifice plate are greatly reduced, and the frequency of instrument maintenance and cleaning is reduced.
However, the device still has the defect that an aerodynamic lens or a nozzle is adopted as a prefocusing piece of the device, a multi-stage orifice plate is required to be assembled for prefocusing in order to improve the focusing effect, so that the speed of aerosol after passing through the prefocusing piece is overlarge, and a buffer cavity with a large size is required to avoid that particles collide with surrounding cavity walls after the aerosol enters the buffer cavity. In addition, the aerodynamic lens used in the application is a seven-stage lens, and the higher the number of stages of the lens, the poorer the coaxiality of the lens due to high assembly accuracy requirements of the aerosol sample injection device.
Disclosure of Invention
The invention aims to disclose a sample injection device and a mass spectrometer for widening the particle size transmission range of an aerodynamic lens, and solve the problems of poor coaxiality caused by overlarge volume and overlarge lens series of the existing aerosol sample injection device.
In order to achieve the above purpose, the invention adopts the following technical scheme:
A sample injection device for widening the particle size transmission range of an aerodynamic lens comprises an aerosol conveying pipe, a first focusing piece and a critical orifice plate, wherein the first end of the aerosol conveying pipe is used for receiving an aerosol sample, the second end of the aerosol conveying pipe is connected with the first end of the first focusing piece, the second end of the first focusing piece is connected with one surface of the critical orifice plate, a first focusing hole is formed in the first focusing piece and used for limiting particle distribution in the aerosol sample, a focusing orifice plate is fixedly arranged in the first focusing hole, a second focusing hole is formed in the focusing orifice plate and used for limiting particle distribution in the aerosol sample again, a critical hole is formed in the critical orifice plate and used for controlling flow of the aerosol sample and adjusting air pressure on two sides of the critical orifice plate, and the first focusing piece and the critical orifice plate are mutually matched to form a vortex cavity which is used for generating a vortex so as to reduce beam width of the aerosol sample after passing through the second focusing hole.
In one embodiment, the aerosol delivery tube, the first focusing aperture, the second focusing aperture, and the critical aperture are all coaxially disposed.
In one embodiment, the inner diameter of the first focusing hole is smaller than the inner diameter of the aerosol conveying pipe, and the first focusing piece and the inner wall of the aerosol conveying pipe are matched with each other to form a first shrinkage step.
In one embodiment, the inner diameter of the second focusing hole is smaller than that of the first focusing hole, and the focusing hole plate and the inner side wall of the first focusing hole are mutually matched to form a second protruding step.
In one embodiment, the bottom surface of the first focusing element is mutually attached to the top surface of the critical orifice plate, and the bottom surface of the focusing orifice plate, the inner side wall of the first focusing orifice and the top surface of the critical orifice plate are mutually matched to form a vortex cavity.
In one embodiment, the critical aperture has an inner diameter less than the inner diameter of the second focusing aperture and the vortex chamber has an inner diameter greater than the inner diameter of the second focusing aperture.
In one embodiment, the first focusing hole has an inner diameter of。
In one embodiment, the second focusing hole has an inner diameter of。
In one embodiment, the height of the first tapered step is。
In one embodiment, the height of the vortex chamber is。
In one embodiment, the vortex chamber has a diameter of。
In one embodiment, the device further comprises a concentration container and a diversion mechanism, wherein the concentration container is fixedly connected with the other surface of the critical orifice plate, a sample inlet is formed in the concentration container, the sample inlet is communicated with the critical orifice, the diversion mechanism is contained in the concentration container, a diversion channel is formed in the diversion mechanism, the diversion channel and the sample inlet are coaxially arranged, and the concentration container is used for pumping air flow in an aerosol sample to concentrate particles in the aerosol sample.
In one embodiment, the inner diameter of the flow guide channel is gradually increased along the particle transmission direction, and the angle between the inner side wall of the flow guide channel and the axis is not more than 15 degrees.
In one embodiment, the sample injection device further comprises a buffer cavity, wherein the buffer cavity is fixedly connected with the concentration container, and the buffer cavity is communicated with the diversion channel.
In one embodiment, the buffer cavity is cylindrical, and the buffer cavity and the diversion channel are coaxially arranged.
In one embodiment, the sample injection device further comprises a second focusing piece, wherein the second focusing piece is fixedly connected with the shell of the buffer cavity, and the second focusing piece is further communicated with the buffer cavity.
In one embodiment, the second focusing element is a five-stage aerodynamic lens.
The aerosol mass spectrometer comprises the sample injection device for widening the particle size transmission range of the aerodynamic lens, and further comprises a mass spectrum vacuum detection mechanism, wherein the mass spectrum vacuum detection mechanism is used for detecting mass spectrum of aerosol particles focused by the sample injection device.
Compared with the prior art, the invention has the beneficial effects that:
The application provides a sample injection device and a mass spectrometer for widening the particle size transmission range of an aerodynamic lens, which comprise an aerosol conveying pipe, a first focusing piece and a critical orifice plate, wherein the first focusing piece is provided with a first focusing hole which is used for limiting particle distribution in the aerosol sample, the first focusing hole is fixedly provided with the focusing orifice plate, the focusing orifice plate is provided with a second focusing hole, the critical orifice plate is provided with a critical hole which is used for controlling flow of the aerosol sample and adjusting air pressure at two sides of the critical orifice plate, the first focusing piece and the critical orifice plate are mutually matched to form a vortex cavity which is used for generating vortex so as to rectify the aerosol sample passing through the second focusing hole, and the vortex cavity is used for rectifying the aerosol sample through the vortex in the vortex cavity, so that the beam width of the aerosol sample can be effectively reduced, the transmission efficiency of the aerodynamic lens on large-diameter particles can be improved, the stage number of the aerodynamic lens for transmitting the large-diameter particles can be reduced, and the assembly difficulty of equipment can be reduced. The sample injection device can effectively widen the particle transmission range of the aerodynamic lens, further improve the particle size detection range of the mass spectrometer, obtain more comprehensive and comprehensive data, cover all size sections from smaller particles to larger particles, and better understand and explain the behavior and effect of the particles.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort to a person skilled in the art.
FIG. 1 is a schematic diagram of the external structure of a sample injection device for widening the particle size transmission range of an aerodynamic lens;
FIG. 2 is a schematic cross-sectional view of the internal structure of the AA part of FIG. 1;
FIG. 3 is an enlarged schematic view of portion A of FIG. 2;
FIG. 4 is an enlarged schematic view of portion B of FIG. 3;
FIG. 5 is a schematic illustration of separate transport of particles from a gas stream in an aerosol sample;
FIG. 6 is a first focusing element size schematic;
FIG. 7 is a simulation of the particle transport efficiency of the examples and comparative examples;
In the figure, 1, an aerosol conveying pipe, 2, a first focusing piece, 21, a first focusing hole, 22, a focusing orifice plate, 23, a second focusing hole, 24, a first shrinkage step, 25, a second shrinkage step, 3, a critical orifice plate, 31, a critical hole, 4, a vortex cavity, 5, a concentration container, 51, a sample inlet, 6, a flow guiding mechanism, 61, a flow guiding channel, 7, a buffer cavity and 8, and a second focusing piece.
Detailed Description
In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected, mechanically connected, electrically connected, directly connected, indirectly connected via an intervening medium, or in communication between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances. The terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature.
In the present invention, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature. The terms "vertical," "horizontal," "left," "right," "up," "down," and the like are used for descriptive purposes only and are not to indicate or imply that the devices or elements being referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the invention.
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments.
To facilitate an understanding of the technical solution, the prior art will first be briefly described. An aerodynamic lens (Aerodynamic Lens) is a device that manipulates tiny particles or aerosol particles by focusing an airflow. The particles and the air flow through a converging nozzle, the air flow velocity increases and the air resistance experienced by the particles increases. The air flow accelerates the particles to a high velocity and concentrates them in the central region of the nozzle. The velocity and pressure of the air flow is repeatedly varied through a series of converging-diverging structures (typically a series of annular nozzles or orifices). This periodic acceleration and deceleration continuously adjusts the trajectories of the particles so that they are eventually focused in a narrow area, i.e., forming a "particle beam". Each time a first lens is added, the particles in the air flow undergo a new acceleration and deceleration process, so that the particles are further concentrated. The greater number of stages of aerodynamic lenses means that the particles can be focused progressively over longer distances, thereby improving the final focusing accuracy and stability, and the multi-stage aerodynamic lens system can better accommodate particles of different particle sizes. Each stage of lens has different focusing effects on particles with different particle diameters, and the combination of a plurality of stages can cover a wider particle diameter range, so that the universality of the system is enhanced. However, the number of the aerodynamic lens stages is not as large as possible, because after each lens stage is assembled with each other, a certain error exists, the multistage lenses are connected with each other, the error also accumulates, and the coaxiality of the center through hole of the aerodynamic lens is further affected, when the error accumulation exceeds the allowable range, the particle transfer effect is affected, and the particle transfer efficiency is reduced. In addition, since the particles have different sizes and different inertias, it is more difficult to change the direction of transmission of particles having larger sizes, in order to increase the aerodynamic particle size transmission range, a method of increasing the number of stages of aerodynamic lenses is generally used in the prior art to increase the aerodynamic particle size transmission range. As disclosed in Chinese patent application No. CN202010615218.3, an aerosol mass spectrum sample feeding device with wide particle size range and an aerosol mass spectrometer are disclosed, the two stages of focusing elements for prefocusing are arranged in front of a critical orifice plate, and a seven-stage lens is arranged behind a buffer cavity, so that the particle size transmission range of the conventional seven-stage lens can be changed from that of a conventional seven-stage lensTo extend toHowever, the application still has the following defects that 1, the method for introducing the prefocusing in the application improves the focusing effect on the particle beam, can improve the transmission speed of the aerosol sample, leads to larger particle divergence angle in the buffer cavity, and needs to set the buffer cavity with larger size to avoid particle loss and avoid collision between particles and the side wall of the buffer cavity. 2. The aerodynamic lens behind the buffer cavity in the application adopts seven-stage lenses, and the pre-focusing two-stage lenses are additionally arranged, so that the series number is more, the assembly difficulty is higher, and the transmission efficiency of the sample injection device can be influenced due to error accumulation.
Example 1
The sample injection device for widening the particle size transmission range of the aerodynamic lens shown in fig. 1-6 comprises an aerosol conveying pipe 1, a first focusing piece 2 and a critical orifice plate 3, wherein a first end of the aerosol conveying pipe 1 is used for receiving an aerosol sample, a second end of the aerosol conveying pipe 1 is connected with the first end of the first focusing piece 2, the second end of the first focusing piece 2 is connected with one surface of the critical orifice plate 3, a first focusing hole 21 is formed in the first focusing piece 2 and used for limiting particle distribution in the aerosol sample, a focusing orifice plate 22 is fixedly arranged in the first focusing hole 21, a second focusing hole 23 is formed in the focusing orifice plate 22 and used for limiting particle distribution in the aerosol sample again, a critical hole 31 is formed in the critical orifice plate 3 and used for controlling flow of the aerosol sample and adjusting air pressure on two sides of the critical orifice plate 3, a first focusing piece 2 and the critical orifice plate 3 are matched with each other to form a vortex flow cavity 4, and then the vortex flow of the aerosol sample is reduced through the first vortex flow cavity 4.
When the sample injection device works, firstly, an aerosol sample is transmitted into the aerosol conveying pipe 1 through one end of the aerosol conveying pipe 1, the aerosol sample passes through the first focusing hole 21 on the first focusing piece 2 and is subjected to first focusing treatment by the first focusing hole 21 so as to reduce the beam width of the aerosol sample, and then, the aerosol sample passes through the second focusing hole 23 on the focusing hole plate 22 and is subjected to second focusing treatment, so that the beam width can be further reduced. The aerosol sample after twice focusing enters the vortex cavity 4, the vortex cavity 4 generates vortex due to the diffusion motion of high-speed gas, the vortex rectifies the subsequent entering gas flow, the beam width of the gas can be further reduced, and finally the aerosol sample after multiple rectification passes through the critical hole 31 and then enters the subsequent concentration container 5 and the buffer cavity 7 for subsequent steps. The pressure difference of the aerosol sample before and after passing through the critical orifice plate 3 is very large, so that the aerosol particles can obtain a large speed, and the aerosol particles can be dispersed in the buffer chamber 7 after passing through the critical orifice 31, forming a conical transmission track. In the sample injection device provided in this embodiment, by rectifying the aerosol sample by using the vortex formed in the vortex cavity 4, the beam width of the aerosol sample can be reduced, and at the same time, the incident angle of the aerosol sample before passing through the critical hole 31 can also be reduced, so that the aerosol sample is more concentrated before passing through the critical hole 31, and further the divergence angle of the aerosol sample after passing through the critical hole 31 is reduced. In summary, according to the present application, by providing the vortex chamber 4 between the first focusing element 2 and the critical orifice plate 3, the beam width of the aerosol sample can be effectively reduced by rectifying the aerosol sample using the vortex generated in the vortex chamber 4.
In summary, after the sample injection device described in the present application is used to pre-focus an aerosol sample, the particle size focusing range of the conventional sample injection device can be widened, and in the prior art, the particle size range in which the five-stage aerodynamic lens can focus is generally betweenParticle size exceeding for aerosol samplesThe transport efficiency of the particles is significantly reduced. If the sample injection device is arranged at the input end of the five-stage aerodynamic lens, the five-stage aerodynamic lens can be obviously improved to have a size between that ofThe transmission efficiency of the particles of the five-stage aerodynamic lens is widened to the transmission range。
In one embodiment, the aerosol delivery tube 1, the first focusing aperture 21, the second focusing aperture 23, and the critical aperture 31 are all coaxially disposed. In practical application, only if the aerosol delivery tube 1, the first focusing hole 21, the second focusing hole 23 and the critical hole 31 are all coaxially arranged, particle loss caused by mutual collision between particles and parts around the focusing holes in the transmission process can be avoided, and the coaxial arrangement of the holes is beneficial to improving the transmission efficiency of the particles.
In one embodiment, the inner diameter of the first focusing hole 21 is smaller than the inner diameter of the aerosol delivery tube 1, and the first focusing element 2 and the inner wall of the aerosol delivery tube 1 are mutually matched to form a first shrinking step 24. The first step 24 is capable of focusing the aerosol sample flowing in the aerosol transport tube for the first time, so that the air flow in the aerosol sample is steadily contracted inwards to drive the particles in the aerosol sample to move towards the central axis.
In one embodiment, the inner diameter of the second focusing hole 23 is smaller than the inner diameter of the first focusing hole 21, and the focusing hole plate 22 and the inner side wall of the first focusing hole 21 cooperate to form a second protruding step 25. The second tapered step 25 forms a continuous step with the first tapered step 24 to further retract the airflow in the aerosol sample inwardly to drive the particles in the aerosol sample to move toward the central axis.
In one embodiment, the bottom surface of the first focusing element 2 is mutually attached to the top surface of the critical orifice plate 3, and the bottom surface of the focusing orifice plate 22, the inner side wall of the first focusing orifice 21 and the top surface of the critical orifice plate 3 are mutually matched to form the vortex cavity 4. In the present application, since the first focusing hole 21 is divided into the upper and lower portions by the focusing hole plate, the inner diameters of the upper and lower portions of the first focusing hole 21 may be equal or unequal, and when the inner diameters of the upper and lower portions of the first focusing hole 21 are unequal, the inner diameter of the vortex chamber 4 is also unequal to the inner diameter of the first focusing hole 21.
In one embodiment, the critical aperture 31 has an inner diameter smaller than the inner diameter of the second focusing aperture 23, and the vortex chamber 4 has an inner diameter larger than the inner diameter of the second focusing aperture 23.
In the application, since the inner diameter of the second focusing hole 23 and the inner diameter of the critical hole 31 are smaller than the inner diameter of the first focusing hole 21, when the bottom surface of the first focusing piece 2 is mutually attached to the critical hole plate 3, the upper surface of the critical hole plate 3, the lower surface of the focusing hole plate and the inner side wall of the first focusing hole form a cylindrical vortex cavity 4, when the focused aerosol sample enters the vortex cavity 4, due to the diffusion motion of gas, vortex is formed in the vortex cavity 4, and the vortex can rectify the aerosol sample passing subsequently, so that the aerosol sample can be more concentrated, and particles of the aerosol sample move towards the axle center under the driving of the airflow, thereby improving the focusing effect. For aerosol particles, the larger the diameter of the particles is, the worse the focusing effect of the particles is, but the vortex cavity 4 is utilized to form vortex flow to rectify the airflow, so that the particles with large size can be effectively pushed to move towards the axis, and the particles which are not aligned with the critical hole 31 are prevented from being mutually collided with the critical orifice plate 3 to cause the loss of the particles. The rectification of the vortex flow can reduce the angle of the airflow entering the critical orifice 31, and the angle of the airflow entering the critical orifice 31 becomes smaller, so that the divergence angle of the particles after passing through the critical orifice 31 and entering the buffer chamber 7 becomes smaller.
In one embodiment, the first focusing hole 21 has an inner diameterIs that。
In one embodiment, the second bore 24 has an inner diameterIs that。
In one embodiment, the vortex chamber 4 has an inner diameterIs that。
In one embodiment, the height of the first tapered step 24Is that。
In one embodiment, the height of the vortex chamber 4Is that。
Based on the above dimensional constraint, the inner diameter of the first focusing hole 21With the inner diameter of the vortex chamber 4The same size may be used, or different sizes may be used. But the inner diameter of the second focus hole 24Must be smaller than the inner diameter of the first focusing hole 21The inner diameter of the vortex chamber 4In this way, the second focusing hole 24 can further focus the aerosol based on the first focusing hole 21, and can also form a vortex in the vortex chamber 4 by the airflow, and further rectify the aerosol sample to reduce the beam width of the airflow in the vortex chamber 4.
In one embodiment, as shown in fig. 5, the device further comprises a concentration container 5 and a diversion mechanism 6, wherein the concentration container 5 is fixedly connected with the other surface of the critical orifice plate 3, a sample inlet 51 is formed in the concentration container 5, the sample inlet 51 is communicated with the critical orifice 31, the diversion mechanism 6 is accommodated in the concentration container 5, a diversion channel 61 is formed in the diversion mechanism 6, the diversion channel 61 and the sample inlet 51 are coaxially arranged, and the concentration container 5 is used for pumping air flow in an aerosol sample to concentrate particles in the aerosol sample. Since the inertia of the particles is larger than that of the gas molecules, the particles can smoothly enter the diversion channel 61 by virtue of the inertia after being accelerated through the critical hole 31, and the gas molecules in the aerosol sample are more easily pumped away, so that concentration of the particles is realized.
In one embodiment, the inner diameter of the guide channel 61 increases gradually in the particle transport direction, and the angle between the inner side wall of the guide channel 61 and the axis is not more than 15 °. When particles pass through the rectification function by vortex flow and can reduce the angle of the air flow entering the critical hole 31, the angle of the air flow entering the critical hole 31 becomes smaller, then the divergence angle of the particles after entering the buffer cavity 7 through the critical hole 31 also becomes smaller, and the sample injection device provided by the application is arranged at the front end of the aerodynamic lens, so that the divergence angle of the particles with the smallest size can be effectively reduced, wherein the divergence angle of the particles can be controlled within 12 degrees, and therefore, the angle of the diversion channel 61 can be controlled within 15 degrees, and the size of the subsequent buffer cavity 7 can be reduced by adjusting the angle of the diversion channel 61.
In one embodiment, the device further comprises a buffer cavity 7, wherein the buffer cavity 7 is fixedly connected with the concentration container 5, and the buffer cavity 7 is communicated with the diversion channel 61. As shown in fig. 5, the flow guiding channel 61 is used for guiding the concentrated aerosol sample which is not pumped into the buffer cavity 7, and since the inertia of the particles is larger than that of the gas molecules, the particles can smoothly enter the flow guiding channel 61 by virtue of inertia after being accelerated through the critical hole 31, and the gas molecules in the aerosol sample are more easily pumped away, so as to realize concentration of the particles, the particles enter the buffer cavity 7 which is near vacuum through the flow guiding channel 61, and the buffer cavity 7 can change the aerosol sample from a turbulent state into a laminar state, thereby facilitating subsequent focusing and bundling. In the application, as the divergence angle of the particles is smaller after entering the buffer cavity, the size of the buffer cavity can be obviously reduced so as to facilitate the miniaturization of the equipment, and in the prior art, the cross-section diameter of the buffer cavity isThe length of the buffer chamber also needsCan meet the transfer efficiency of the particulate matters, and the diameter of the buffer cavity in the invention can be reduced toThe length of the buffer cavity can be reduced toThe particulate matter transfer efficiency can be satisfied.
In one embodiment, the buffer chamber 7 is cylindrical, and the buffer chamber 7 is coaxially arranged with the diversion channel 61.
In one embodiment, the device further comprises a second focusing element 8, wherein the second focusing element 8 is fixedly connected with the shell of the buffer cavity 7, and the second focusing element 8 is also communicated with the buffer cavity 7.
In one embodiment, the second focusing element 8 is a five-stage aerodynamic lens.
Conventional five-stage aerodynamic lenses are capable of focusing only betweenFor the particles of (2)The transport efficiency of particles in the size range is significantly reduced. The sample injection device and the five-stage aerodynamic lens are combined with each other, so that the sample injection device can be effectively liftedIs not limited, and the transfer efficiency of the particles is improved. Compared with the prior art, the aerodynamic lens has fewer stages and smaller assembly error, and can effectively reduce the assembly difficulty of equipment.
Example two
An aerosol mass spectrometer comprises a sample injection device for widening the particle size transmission range of an aerodynamic lens as in the first embodiment, and further comprises a mass spectrum vacuum detection mechanism for detecting mass spectrum of aerosol particles focused by the sample injection device. The sample injection device in the first embodiment can effectively widen the particle transmission range of the aerodynamic lens, further improve the particle size detection range of the aerosol mass spectrometer, obtain more comprehensive and comprehensive data, cover all size sections from smaller particles to larger particles, and better understand and explain the behavior and effect of the particles.
Example III
As shown in fig. 7, the present application further provides two comparative examples to highlight the technical effects of the sample injection device including the first focusing element described in embodiment 1, where the comparative examples specifically include the following three structures:
embodiment 1. The sample introduction device as provided in embodiment 1 is used, wherein a vortex cavity is provided between the first focusing element and the critical orifice plate, and the second focusing element is a five-stage aerodynamic lens.
Comparative example 1 an aerosol mass spectrometer sample injection device with a wide particle size range as proposed in the patent of the invention (application number: CN 202010615218.3) was used, a two-stage aerodynamic lens was placed in front of the buffer chamber for pre-focusing, and the aerodynamic lens behind the buffer chamber was seven stages.
Comparative example 2 two stages of aerodynamic lenses were placed before the buffer chamber for pre-focusing and five stages of aerodynamic lenses were placed after the buffer chamber for focusing.
Comparing example 1 with comparative example 1, the structure of comparative example 1 is capable of transporting a particle size ofThe structure in the embodiment 1 can achieve the same transmission efficiency under the condition of reducing the number of the aerodynamic lens stages, effectively reduces the assembly difficulty of the sample injection device, and avoids the influence on the stability of the final equipment due to error accumulation in the assembly process of the multistage aerodynamic lens.
In the case of the five-stage aerodynamic lens used in comparative example 2, even if the two-stage aerodynamic lens is added between critical aperture plates for prefocusing, in the case of comparing example 1 with comparative example 2A kind of electronic deviceIn the range, the transfer efficiency is obviously reduced, and the sample injection device in the embodiment 1 of the application is matched with the five-stage aerodynamic lens, so that the efficiency can be effectively improvedA range of particle transfer efficiencies.
In summary, the sample injection device for widening the particle size transmission range of the aerodynamic lens can be used for widening the particle size range in the prior artThe particle size transmission range of the five-stage aerodynamic lens of (2) is widened to. And the number of stages of the aerodynamic lens can be reduced while the particle transmission in the wide particle size range is realized, so that the accumulation of assembly errors is reduced, and the assembly difficulty is reduced.
The present invention is not limited to the above-described embodiments, but, if various modifications or variations of the present invention are not departing from the spirit and scope of the present invention, the present invention is intended to include such modifications and variations as fall within the scope of the claims and the equivalents thereof.
Claims (5)
1. The sample injection device for widening the particle size transmission range of the aerodynamic lens is characterized by comprising an aerosol conveying pipe, a first focusing piece and a critical orifice plate;
the first end of the aerosol conveying pipe is used for receiving an aerosol sample, the second end of the aerosol conveying pipe is connected with the first end of the first focusing piece, and the second end of the first focusing piece is connected with one surface of the critical orifice plate;
a first focusing hole is formed in the first focusing piece and used for limiting particle distribution in the aerosol sample;
A focusing pore plate is fixedly arranged in the first focusing pore plate, a second focusing pore is arranged on the focusing pore plate, and the second focusing pore is used for limiting the particle distribution in the aerosol sample again;
the critical pore plate is provided with critical pores which are used for controlling the flow of aerosol samples and adjusting the air pressure at two sides of the critical pore plate;
the aerosol conveying pipe, the first focusing hole, the second focusing hole and the critical hole are all coaxially arranged;
the bottom surface of the focusing orifice plate, the top surface of the critical orifice plate and the inner side wall of the first focusing orifice positioned between the bottom surface of the focusing orifice plate and the top surface of the critical orifice plate are mutually matched to form a vortex cavity, and the vortex cavity is used for generating vortex so as to reduce the beam width of an aerosol sample passing through the second focusing orifice;
An inner diameter of the first focusing hole between the second end of the aerosol delivery tube and the top surface of the focusing orifice plate The first focusing piece is matched with the inner wall of the aerosol conveying pipe to form a first shrinkage step;
The inner diameter of the second focusing hole Is smaller than the inner diameter of the first focusing holeThe top surface of the focusing hole plate is matched with the inner side wall of the first focusing hole to form a second protruding step;
The inner diameter of the critical hole is smaller than that of the second focusing hole The inner diameter of the vortex cavityIs larger than the inner diameter of the second focusing hole;
The inner diameter of the first focusing holeIs that;
The inner diameter of the second focusing holeIs that;
The inner diameter of the vortex cavityIs that;
The height of the first protruding stepIs that;
Height of the vortex cavityIs that。
2. The sample injection device for widening the particle size transmission range of the aerodynamic lens according to claim 1, further comprising a concentration container and a flow guiding mechanism, wherein the concentration container is fixedly connected with the other surface of the critical orifice plate, and a sample injection port is formed in the concentration container and communicated with the critical orifice;
The flow guide mechanism is accommodated in the concentrating container, a flow guide channel is arranged in the flow guide mechanism, and the flow guide channel and the sample inlet are coaxially arranged;
The concentration container is used for pumping the airflow in the aerosol sample to concentrate particles in the aerosol sample.
3. The sample injection device for widening the particle size transmission range of an aerodynamic lens according to claim 2, wherein the inner diameter of the flow guide channel gradually increases along the particle transmission direction, and the angle between the inner side wall of the flow guide channel and the axis is not more than 15 °.
4. The sample injection device for widening the particle size transmission range of the aerodynamic lens according to claim 3, further comprising a buffer cavity and a second focusing piece, wherein the buffer cavity is fixedly connected with the concentration container, the buffer cavity is communicated with the diversion channel, the second focusing piece is fixedly connected with a shell of the buffer cavity, the second focusing piece is also communicated with the buffer cavity, and the second focusing piece is a five-stage aerodynamic lens.
5. An aerosol mass spectrometer, comprising a sample injection device for widening the particle size transmission range of an aerodynamic lens according to any one of claims 1-4, and further comprising a mass spectrum vacuum detection mechanism for mass spectrum detection of aerosol particles focused by the sample injection device.
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| JP3349965B2 (en) * | 1998-11-05 | 2002-11-25 | 松下電器産業株式会社 | Fine particle classification method and apparatus |
| US7476851B2 (en) * | 2004-11-12 | 2009-01-13 | Regents Of The University Of Minnesota | Aerodynamic focusing of nanoparticle or cluster beams |
| CN109752224B (en) * | 2017-11-06 | 2023-11-28 | 广州禾信仪器股份有限公司 | Concentrating device and pneumatic focusing system |
| CN113871285B (en) * | 2020-06-30 | 2023-02-24 | 广州禾信仪器股份有限公司 | Aerosol mass spectrum sampling device with wide particle size range and aerosol mass spectrometer |
| CN115938909B (en) * | 2022-11-22 | 2024-04-19 | 广东智普生命科技有限公司 | Laser-coupled electrospray extraction ionization source and analysis system |
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