Liquid film sampling device

Abstract

The invention discloses a liquid film sampling device, and belongs to the field of liquid film sampling detection. Comprises: a housing main body having a first port and a second port communicated with each other; one end of the thin pipe is positioned in the second opening and is basically flush with the end part of the second opening, and the other end of the thin pipe penetrates through the shell main body and is connected to the atomizing nozzle; the liquid path circulating mechanism comprises a first pump body communicated with the first opening and a second pump body communicated with the thin pipe; and the heating device is arranged at the periphery of the thin tube and is used for forming a heating section for the thin tube so as to improve the flowability of the sample-containing liquid flowing through the thin tube and reduce the adhesion of the sample on the inner wall of the thin tube. The device has the beneficial effects that the heating wire is arranged outside the thin tube and the temperature is controlled, so that the flowability and the temperature of sample-containing liquid are improved, the viscosity of the liquid is reduced, particulate matters such as dust and impurities are unlikely to form lasting adhesion on the inner wall of the thin tube, and the influence of tube wall deposition on a detection result is greatly reduced.

Description

A liquid film sampling device Technical Field

[0001] This application relates to the field of liquid film sampling and detection, and more specifically, to a liquid film sampling device. Background Technology

[0002] In fields such as air quality monitoring, cleanroom monitoring, and environmental safety monitoring, it is often necessary to sample and test dust, particulate matter, and soluble or absorbable gaseous pollutants in the air.

[0003] Liquid film sampling is a commonly used sampling method: by forming a stable liquid film at a specific structure, the outside air is fully contacted with the liquid film, thereby transferring and capturing dust, impurities or soluble substances in the air into the liquid, and then the sample is analyzed by the downstream detection equipment.

[0004] In existing technologies, liquid films are typically formed by liquid at an opening or slit, naturally contacting the outside air and achieving adsorption and dissolution. After sampling, the liquid is usually transported to the detection unit through a capillary tube. However, the capillary tube has a small diameter, and the sample composition is complex, especially when it contains dust particles, adhesive substances, and components that may undergo precipitation reactions. This makes it prone to deposition, adhesion, or blockage on the inner wall of the capillary tube. This not only affects the sampling flow rate and stability, causing fluctuations in detection results, but may also lead to significant deviations between the measured results and the actual sample concentration. Summary of the Invention

[0005] The summary section of this application is intended to provide a brief overview of the concepts, which will be described in detail in the detailed description section below. This summary section is not intended to identify key or essential features of the claimed technical solutions, nor is it intended to limit the scope of the claimed technical solutions.

[0006] To address the technical problems mentioned in the background section above, some embodiments of this application provide a liquid film sampling device, comprising: a housing body having a first port and a second port communicating with each other; a thin tube, one end of which is located inside the second port and substantially flush with the end of the second port, the other end of which passes through the housing body and is connected to an atomizing nozzle; a liquid circulation mechanism including a first pump body communicating with the first port and a second pump body communicating with the thin tube, the first pump body being used to transport liquid from the first port to the second port, and the second pump body being used to draw liquid flow from the thin tube at the second port to form a liquid film between the second port and the end of the thin tube; and a heating device disposed on the outer periphery of the thin tube to form a heating section on the thin tube to improve the flowability of the sample-containing liquid flowing through the thin tube and reduce the adhesion of the sample to the inner wall of the thin tube.

[0007] Furthermore, the heating device includes: at least one heating wire wound around the outer periphery of the thin tube; the two ends of the heating wire are respectively connected to the positive and negative terminals of an external power source, so that the heating wire is energized and heats up to heat the thin tube.

[0008] Furthermore, the heating device includes multiple heating wires, each of which forms multiple independent heating sections along the extension direction of the thin tube; both ends of each heating wire are independently connected to the positive and negative terminals of an external power source.

[0009] Furthermore, the heating device also includes multiple sleeves, which are fitted around the outer periphery of the thin tube; the heating wire is disposed on the inner wall of the corresponding sleeve.

[0010] Furthermore, each of the sleeves is provided with an angle sensor, which is used to detect the tilt angle of the sleeve and to identify whether the thin tube is a bent section or a straight section at that position.

[0011] Furthermore, each of the sleeves is also provided with a current controller, which is electrically connected to the corresponding heating wire and is used to control the on / off state, magnitude and direction of the current of the heating wire; wherein, the heating wire is wound around the outer periphery of the thin tube to form an energized solenoid to generate a magnetic field inside the thin tube.

[0012] Furthermore, the control unit determines the bending position of the thin tube based on the tilt angles of the multiple sleeves; the control unit is configured to: acquire the tilt angles of two adjacent sleeves; if the difference in tilt angles between two adjacent sleeves is greater than a preset threshold, then the thin tube between them is determined to be a bending segment; the sleeve located before the bend is set as the pre-deceleration sleeve, and the sleeve located after the bend and the sleeves whose tilt angle difference between two adjacent sleeves is less than the preset threshold are all set as the post-acceleration sleeve; the current controller causes the heating wire current of the pre-deceleration sleeve to flow in a first direction and causes the heating wire current of the post-acceleration sleeve to flow in a second direction; the first direction and the second direction are opposite.

[0013] Furthermore, the liquid is water, acetaldehyde, or other absorbent liquid selected according to the characteristics of the target sample.

[0014] A sampling method of the above-mentioned sampling device includes: conveying liquid from a first port to a second port through a first pump body, and forming an outwardly sprayed liquid flow at the second port; applying suction to the liquid flow at the second port from one end of a thin tube through a second pump body, so that the liquid flow originally sprayed outward through the second port is drawn into the thin tube, forming a liquid film between the second port and the end of the thin tube for capturing dust and impurities in the air; controlling a heating device to form at least one heating section in the thin tube, so that the temperature of the liquid flowing through the thin tube is increased to improve fluidity and reduce the adhesion of dust and impurities to the inner wall of the thin tube.

[0015] Furthermore, the control unit determines the bending position of the thin tube based on the tilt angle of the multiple sleeves; if the tilt angle difference between two adjacent sleeves is greater than a preset threshold, the thin tube between them is determined to be a bent section; the sleeve located before the bend is set as the pre-deceleration sleeve, and the sleeve located after the bend and the sleeves with a tilt angle difference between two adjacent sleeves less than the preset threshold are all set as the post-acceleration sleeve; the current controller causes the heating wire current of the pre-deceleration sleeve to flow in a first direction and causes the heating wire current of the post-acceleration sleeve to flow in a second direction; the first direction and the second direction are opposite.

[0016] The beneficial effects of this application are as follows:

[0017] By installing a heating wire on the outside of the thin tube and controlling the temperature, the fluidity and temperature of the sample-containing liquid are improved, the viscosity of the liquid is reduced, and particulate matter such as dust and impurities are less likely to form persistent adhesion on the inner wall of the thin tube, thus greatly reducing the impact of tube wall deposition on the test results.

[0018] The electrically heated wire not only provides heating but also creates a magnetic field around the circumference of the thin tube in the form of a spiral coil. This magnetic field promotes more complete movement of particles in the liquid, resulting in a more uniform distribution of particles within the tube's cross-section, shortening the residence time of particles near specific wall surfaces, and further reducing the probability of adhesion.

[0019] By integrating angle sensors on multiple sleeves arranged along the thin tube, the tilt angle or bending information at different positions is acquired in real time. The current controller then adjusts the direction and magnitude of the current in each heating wire based on this information, achieving differentiated control of the magnetic field direction and intensity in different tube sections. Especially before and after the thin tube bends, magnetic fields with opposite directions or different intensities can be formed by adjacent sleeves to decelerate or dampen particles, effectively reducing the probability of their impact and deposition on the bent wall surface.

[0020] The sleeve is an independent module with a heating wire, power connector and angle sensor, which can be flexibly arranged on thin tubes of different lengths and bending shapes. The number can be selectively installed or adjusted according to the actual tube layout, and it is suitable for a variety of monitoring and sampling scenarios.

[0021] By integrating angle sensing and current control interfaces on the bushing, communication with a controller or host computer can be achieved to build an intelligent control system, realizing automated adjustment of temperature and magnetic field distribution, which helps to form a miniaturized, integrated, and highly reliable liquid film sampling and delivery device. Attached Figure Description

[0022] The accompanying drawings, which form part of this application, are used to provide a further understanding of the application and to make other features, objects, and advantages of the application more apparent. The illustrative embodiments and descriptions of this application are used to explain the application and do not constitute an undue limitation of the application.

[0023] Furthermore, throughout the accompanying drawings, the same or similar reference numerals denote the same or similar elements. It should be understood that the drawings are schematic, and the elements are not necessarily drawn to scale.

[0024] In the attached diagram:

[0025] Figure 1 is an overall schematic diagram according to an embodiment of this application;

[0026] Figure 2 is a structural schematic diagram of a part of the embodiment, mainly showing the cross-sectional structure of Figure 1;

[0027] Figure 3 is a structural schematic diagram of a part of the embodiment, mainly showing the cross-sectional structure of the outer shell body;

[0028] Figure 4 is a structural schematic diagram of a part of the embodiment, mainly showing the cross-sectional structure of the second connector.

[0029] Figure label:

[0030] 1. Outer shell; 11. Main connector; 12. First connector; 13. Second connector; 14. Third connector; 2. Thin tube; 21. Bending section; 3. Atomizing nozzle; 4. Liquid circulation mechanism; 41. First pump body; 42. Second pump body; 5. Heating device; 51. Heating wire; 52. Sleeve. Detailed Implementation

[0031] Embodiments of this disclosure will now be described in more detail with reference to the accompanying drawings. While some embodiments of this disclosure are shown in the drawings, it should be understood that this disclosure can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this disclosure. It should be understood that the accompanying drawings and embodiments of this disclosure are for illustrative purposes only and are not intended to limit the scope of protection of this disclosure.

[0032] It should also be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings. Unless otherwise specified, the embodiments and features described in this disclosure can be combined with each other.

[0033] It should be noted that the concepts of "first" and "second" mentioned in this disclosure are used only to distinguish different devices, modules or units, and are not used to limit the order of functions performed by these devices, modules or units or their interdependencies.

[0034] It should be noted that the terms "a" and "a plurality of" used in this disclosure are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0035] This disclosure will now be described in detail with reference to the accompanying drawings and embodiments.

[0036] Refer to Figure 1-4.

[0037] This embodiment provides a liquid film sampling device, including: a housing body 1; the housing body 1 has a first port and a second port that are interconnected.

[0038] In a typical embodiment, the outer shell body 1 may be a "T"-shaped or "Y"-shaped connector structure, with the first port connected to an external liquid storage tank or pipeline, and the second port facing the outside air, used to form a liquid film at its opening.

[0039] It also includes: a capillary tube 2; one end of the capillary tube 2 is located inside the second opening, and preferably is substantially flush with the end of the second opening, so that a liquid film can be stably formed between the second opening and the end of the capillary tube 2.

[0040] The other end of the capillary tube 2 passes through the outer casing 1 and is connected to the nebulizer nozzle 3. The nebulizer nozzle 3 can be used to further atomize the liquid containing the sample and deliver it to downstream analytical devices, such as spectroscopic detection, chromatographic analysis, or other online monitoring equipment.

[0041] The thin tube 2 can be made of inert materials, such as polytetrafluoroethylene (PTFE), PFA, or stainless steel with an inner coating, to reduce the adsorption of the target analyte. However, even with inert materials, particles can still easily adhere to the inner wall of the tube under conditions of small diameter and multiple bends, so the heating scheme of this invention is still necessary.

[0042] It also includes a liquid circulation mechanism 4; the liquid circulation mechanism 4 is used to form a stable liquid flow within the outer casing 1 and to provide conditions for the formation and maintenance of a liquid film. The liquid circulation mechanism 4 includes a first pump body 41 and a second pump body 42. The first pump body 41 is connected to a first port and is used to transport liquid from the first port to a second port, forming an outwardly ejected liquid flow at the second port; the second pump body 42 is connected to a capillary tube 2 and is used to draw the liquid flow from the second port through the capillary tube 2, so that the liquid flow that should have been ejected from the second port is drawn into the capillary tube 2, forming a liquid film between the second port and the end of the capillary tube 2. The liquid can be water, acetaldehyde, or other absorbent liquid selected according to the characteristics of the target sample.

[0043] In some embodiments, the outer casing 1 has a "T-shaped passage" forming a first opening, a second opening, and a third opening. The outer casing 1 includes a main connector 11, a first connector 12, a second connector 13, and a third connector 14. The first connector 12 forms the first opening, the second connector 13 forms the second opening, and the third connector 14 forms the third opening. A thin tube 2 extends from the third tube into the outer casing 1, and the end of the thin tube 2 is located at the second opening. The thin tube 2 is flush with the second opening, or the end of the thin tube 2 is slightly lower than the second opening. The diameter of the thin tube 2 is smaller than the diameter of the second opening.

[0044] In one embodiment, the first pump body 41 may be a constant flow pump, peristaltic pump or gear pump, etc., with adjustable output flow rate; the second pump body 42 may be a negative pressure pump or suction pump, and by adjusting its suction flow rate, the thickness and stability of the liquid film can be precisely controlled.

[0045] The first pump body 41 and the second pump body 42 can be controlled in a coordinated manner, for example, through closed-loop regulation via the same control unit, so that the flow rate and liquid level inside the outer casing 1 are within a preset range.

[0046] It also includes: a heating device 5; a heating device 5 is provided on the outer periphery of the capillary tube 2 to form at least one heating section, thereby increasing the temperature of the sample-containing liquid flowing through the capillary tube 2, improving its fluidity, and reducing the adhesion of dust and impurities to the inner wall of the capillary tube 2.

[0047] The heating device 5 is located on the outer periphery of the thin tube 2.

[0048] The first option for the heating device 5 is: a single heating wire 51 forms a single heating section;

[0049] The heating device 5 includes a heating wire 51, which is wound around the outer periphery of the thin tube 2. The two ends of the heating wire 51 are respectively connected to the positive and negative terminals of an external power source, so that the heating wire 51 is energized and heats up, thereby heating the thin tube 2.

[0050] In this embodiment, a single heating wire 51 can be spirally wound along a section of the axial length of the thin tube 2 to form a heating section of fixed length.

[0051] The heating power can be controlled by adjusting the voltage and current of the external power supply, thereby controlling the temperature range of the heating section. For example, the liquid temperature inside the thin tube 2 can be controlled to be slightly higher than the ambient temperature to reduce the impact of temperature fluctuations on the sample properties.

[0052] The second option for heating device 5 is: multiple heating wires 51 form multiple independent heating sections.

[0053] To address the potential risks of multiple bends or adhesions at different locations on the thin tube 2, the heating device 5 may include multiple heating wires 51, which are respectively arranged along the extension direction of the thin tube 2 to form multiple independent heating sections.

[0054] Specifically:

[0055] The axial coverage length of each heating wire 51 can be the same or different; each heating segment can correspond to a straight segment or a key bend on the thin tube 2; both ends of each heating wire 51 are independently connected to the positive and negative terminals of an external power supply, enabling independent on / off switching and power control. By independently controlling different heating segments, the risk of sample adhesion at specific locations can be reduced, for example, by applying relatively higher heating power to the bend segment 21 or areas prone to gravity retention.

[0056] The third option for heating device 5 is: the sleeve 52 structure is integrated with the heating wire 51.

[0057] The heating device 5 also includes multiple sleeves 52, each sleeve 52 being fitted around the outer periphery of the thin tube 2. Heating wires 51 are disposed on the inner wall of the corresponding sleeve 52. The sleeves 52 can be made of high-temperature resistant and corrosion-resistant insulating materials, such as polyimide, PPS, ceramics, or glass fiber reinforced materials, serving both a supporting and protective function while providing an electrical insulation environment. The sleeves 52 facilitate installation on the thin tube 2.

[0058] The fourth option for heating device 5 is:

[0059] Each sleeve 52 is equipped with an angle sensor, which is used to detect the tilt angle of the sleeve 52, thereby identifying whether the thin tube 2 is a bent section 21 or a relatively straight section at that position.

[0060] Specifically: the angle sensor can be a gyroscope or an electronic level, etc.; when the thin tube 2 is laid out along the spatial path, each sleeve 52 is fixedly connected to the thin tube 2, so the attitude of the sleeve 52 can reflect the spatial tilt angle of the thin tube 2 at the corresponding position;

[0061] By reading the output values ​​of each angle sensor, the control unit can construct the spatial attitude distribution of the thin tube 2, thereby accurately identifying the interval where the bending segment 21 is located.

[0062] Each sleeve 52 is also equipped with a current controller, which is electrically connected to the corresponding heating wire 51 and is used to control the on / off state, magnitude and direction of the current in the heating wire 51.

[0063] The heating wire 51 is wound around the outer periphery of the thin tube 2 to form an energized solenoid structure. When current passes through it, it can not only generate heat to heat the thin tube 2, but also generate a magnetic field inside the thin tube 2.

[0064] By changing the direction of the current through a current controller, the direction of the magnetic field can be reversed.

[0065] For particles with magnetic response characteristics (such as samples carrying magnetically labeled particles), the changes in the direction and intensity of the magnetic field can be used to a certain extent to assist the transport of particles along the inside of the capillary tube 2, reducing their residence and deposition on the inner wall.

[0066] The following steps can be performed via the control unit:

[0067] Obtain the tilt angles of multiple sleeves 52;

[0068] Obtain the tilt angle difference between two adjacent sleeves 52;

[0069] If the difference in tilt angle between two adjacent sleeves 52 is greater than a preset threshold, then the thin tube 2 between them is determined to be a bent section 21.

[0070] The sleeve 52 located on the side before the bend is set as the pre-deceleration sleeve 52, and the sleeve 52 located on the side after the bend and the sleeve 52 with the inclination angle difference between two adjacent sleeves 52 being less than a preset threshold are all set as the post-acceleration sleeve 52.

[0071] The current controller causes the heating wire 51 of the pre-deceleration bushing 52 to flow in a first direction, and causes the heating wire 51 of the post-acceleration bushing 52 to flow in a second direction, with the first direction being opposite to the second direction.

[0072] With the above settings, currents and magnetic fields in opposite directions can be generated before and after the bend, thereby providing different guiding or constraining effects on magnetically responsive particles in selectable scenarios. At the same time, by adjusting the heating power of different sleeves 52, the flow velocity and temperature distribution before and after the bend can be made more favorable for particles to pass through the bend area, reducing their retention and deposition at the bend.

[0073] For example, the control unit can set the pre-bending sleeve 52 to a lower heating power to slightly reduce the local flow rate, allowing the particles to undergo some flow adjustment before approaching the bending section 21; while the post-bending sleeve 52 can be set to a higher heating power to improve the fluidity and velocity of the liquid in that section, making it easier for the particles to leave the high-risk bending area as soon as possible.

[0074] Some embodiments provide a sampling method for the liquid film sampling device of the above embodiments, including the following steps:

[0075] S1: The liquid is transported from the first port to the second port through the first pump body 41, forming an outward jet of liquid at the second port.

[0076] S2: The second pump body 42 applies suction to the liquid flow at the second opening from one end of the capillary tube 2, causing the liquid flow that was originally sprayed outward from the second opening to be drawn into the capillary tube 2, forming a liquid film L between the second opening and the end of the capillary tube 2. This liquid film is in direct contact with the outside air and is used to capture dust, impurities and other particles in the air.

[0077] Heating control to reduce adhesion

[0078] S3: Control the heating device 5 to form at least one heating section on the thin tube 2, so that the temperature of the liquid flowing through the thin tube 2 increases, improves the fluidity of the liquid, and reduces the adhesion of dust and impurities on the inner wall of the thin tube 2.

[0079] In a simplified implementation, the entire length of the capillary tube 2 or its main working section can be set to a constant temperature;

[0080] In complex implementations, heating sections with different power levels can be set according to the degree of bending at different locations and the risk of sample retention.

[0081] The method may also include:

[0082] S4: The control unit determines the bending position of the thin tube 2 based on the tilt angle of the multiple sleeves 52.

[0083] If the difference in tilt angle between two adjacent sleeves 52 is greater than a preset threshold, then the thin tube 2 between them is determined to be a bent section 21.

[0084] S5: Based on the judgment result, the sleeve 52 located before the bend is set as the pre-deceleration sleeve 52, and the sleeve 52 located after the bend and the sleeve 52 with an inclination angle difference of less than a preset threshold are all set as the post-acceleration sleeve 52.

[0085] S6: Through their respective current controllers, the current of the heating wire 51 of the pre-deceleration bushing 52 flows in a first direction, and the current of the heating wire 51 of the post-acceleration bushing 52 flows in a second direction, wherein the first direction and the second direction are opposite.

[0086] By using the above method, while ensuring the stable capture of airborne particulate matter by the liquid film, the adhesion and deposition of samples in the capillary tube 2 can be significantly reduced, thereby improving sampling efficiency and the reliability of long-term online operation.

[0087] The above description is merely a selection of preferred embodiments of this disclosure and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in the embodiments of this disclosure is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions disclosed in the embodiments of this disclosure.

Claims

1. A liquid film sampling device, characterized in that, include: The outer casing body has a first opening and a second opening that are interconnected. A thin tube, one end of which is located inside the second port and is substantially flush with the end of the second port, and the other end of the thin tube passes through the outer shell body and is connected to the atomizing nozzle; a liquid circulation mechanism, including a first pump body communicating with the first port and a second pump body communicating with the thin tube, the first pump body being used to deliver liquid from the first port to the second port, and the second pump body being used to draw liquid flow from the thin tube at the second port to form a liquid film between the second port and the end of the thin tube; A heating device is disposed on the outer periphery of the thin tube to form a heating section on the thin tube, thereby improving the flowability of the sample-containing liquid flowing through the thin tube and reducing the adhesion of the sample to the inner wall of the thin tube.

2. The liquid film sampling device according to claim 1, characterized in that: The heating device includes: at least one heating wire wound around the outer periphery of the thin tube; the two ends of the heating wire are respectively connected to the positive and negative terminals of an external power source, so that the heating wire is energized and generates heat to heat the thin tube.

3. The liquid film sampling device according to claim 1, characterized in that: The heating device includes multiple heating wires, which form multiple independent heating sections along the extension direction of the thin tube; the two ends of each heating wire are independently connected to the positive and negative terminals of an external power source.

4. The liquid film sampling device according to claim 2 or 3, characterized in that: The heating device also includes multiple sleeves, which are fitted around the outer periphery of the thin tube; the heating wire is disposed on the inner wall of the corresponding sleeve.

5. The liquid film sampling device according to claim 4, characterized in that: Each of the sleeves is equipped with an angle sensor, which is used to detect the tilt angle of the sleeve and to identify whether the thin tube is a bent section or a straight section at that position.

6. The liquid film sampling device according to claim 5, characterized in that: Each of the sleeves is also provided with a current controller, which is electrically connected to the corresponding heating wire and is used to control the on / off state, magnitude and direction of the current in the heating wire; wherein, the heating wire is wound around the outer periphery of the thin tube to form an energized solenoid to generate a magnetic field inside the thin tube.

7. The liquid film sampling device according to claim 6, characterized in that: The control unit determines the bending position of the thin tube based on the tilt angles of the multiple sleeves. The control unit is configured to: acquire the tilt angles of two adjacent sleeves; if the difference in tilt angles between two adjacent sleeves is greater than a preset threshold, then the thin tube between them is determined to be a bending segment; the sleeve located before the bend is designated as the pre-deceleration sleeve, and the sleeve located after the bend and the sleeves with a tilt angle difference between two adjacent sleeves less than the preset threshold are designated as the post-acceleration sleeves; the current controller causes the heating wire current of the pre-deceleration sleeve to flow in a first direction and causes the heating wire current of the post-acceleration sleeve to flow in a second direction; the first direction and the second direction are opposite.

8. The liquid film sampling device according to claim 1, characterized in that: The liquid is water, acetaldehyde, or other absorbent liquid selected according to the characteristics of the target sample.

9. A sampling method using the sampling device as described in any one of claims 1-8, characterized in that, include: The first pump body delivers liquid from the first port to the second port, forming an outward-spraying liquid flow at the second port. The second pump body applies suction to the liquid flow at the second port from one end of the thin tube, causing the liquid flow that was originally sprayed outward through the second port to be drawn into the thin tube, forming a liquid film between the second port and the end of the thin tube to capture dust and impurities in the air. The heating device controls the thin tube to form at least one heating section, raising the temperature of the liquid flowing through the thin tube to improve its fluidity and reduce the adhesion of dust and impurities to the inner wall of the thin tube.

10. The sampling method according to claim 9, characterized in that: Also includes: The control unit determines the bending position of the thin tube based on the tilt angle of the multiple sleeves; if the tilt angle difference between two adjacent sleeves is greater than a preset threshold, the thin tube between them is determined to be a bending segment; the sleeve located before the bend is set as the pre-deceleration sleeve, and the sleeve located after the bend and the sleeves with a tilt angle difference between two adjacent sleeves less than the preset threshold are all set as the post-acceleration sleeve; the current controller causes the heating wire current of the pre-deceleration sleeve to flow in a first direction and causes the heating wire current of the post-acceleration sleeve to flow in a second direction; the first direction and the second direction are opposite.

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