Combined sampler for chemical detection

Abstract

The embodiment of the present disclosure provides a combined sampler for chemical detection, which comprises a sampling needle for inserting into a reaction container and extracting a liquid sample to be detected; a sample chamber connected with the sampling needle; a sealing ring located between the sampling needle and the sample chamber; and an exhaust valve arranged on the upper end of the sample chamber and used for balancing the pressure in the sample chamber so as to extract and inject the sample; wherein: a spiral flow channel is arranged in the sampling needle; the sampling needle has a smooth taper structure at the end; an annular groove is arranged on the outer wall of the sampling needle, and the annular groove is filled with elastic sealing material; and a plurality of groups of shunt plates are arranged in the sampling needle, and the shunt plates are distributed at intervals along the spiral flow channel. Through the scheme of the embodiment of the present disclosure, the stratification or uneven mixing of the sample can be prevented.

Description

Technical Field

[0001] This application relates to the field of chemical analysis instruments and technology, specifically to a combined sampler for chemical testing. Background Technology

[0002] The combined sampler for chemical testing is a specialized device that integrates modules such as multi-layer sampling tubes, adjustable flow dividers, and dynamic mixing chambers to achieve segmented collection and preliminary mixing of samples of different densities, phases, or reaction stages in chemical processes. Its design focuses on improving the representativeness and operational efficiency of sampling complex media. However, in practical applications, this device faces technical challenges related to sample stratification or uneven mixing. This is mainly manifested in high-viscosity fluids and multiphase mixtures where, during sampling, insufficient gravity settling, turbulent disturbance, or deviations in flow divider timing lead to deviations in the distribution of components within the sample from the actual operating conditions, directly affecting the reliability of the test data. Summary of the Invention

[0003] In view of this, the present disclosure provides a combined sampler for chemical testing, which at least partially solves the problems existing in the prior art.

[0004] This application discloses a combined sampler for chemical testing, comprising:

[0005] A sampling needle is used to insert into a reaction vessel and extract a liquid sample to be tested.

[0006] The sample chamber is connected to the sampling needle;

[0007] A sealing ring is located between the sampling needle and the sample chamber;

[0008] An exhaust valve, located at the upper end of the sample chamber, is used to balance the pressure inside the sample chamber for sample extraction and injection; wherein:

[0009] The sampling needle is equipped with a spiral flow channel;

[0010] The sampling needle tip has a smooth tapering structure;

[0011] The outer wall of the sampling needle is provided with an annular groove, and the annular groove is filled with elastic sealing material;

[0012] The sampling needle is equipped with multiple flow dividers, which are distributed at intervals along the spiral flow channel.

[0013] According to one embodiment, the helical angle α of the helical flow channel is 30° to 45° to optimize the fluid flow path.

[0014] According to one embodiment, the diameter of the smooth tapering structure gradually decreases at the end, with a minimum inner diameter of 5 mm to 1 mm, to prevent the sample from delaminating at the needle inlet.

[0015] According to one embodiment, the elastic sealing material filling the annular groove is made of silicone rubber, and its compression ratio is maintained at 20% to 30%.

[0016] According to one embodiment, a rubber stopper is provided in the sample chamber, one end of the rubber stopper is connected to a piston rod, and the end of the piston rod away from the rubber stopper is connected to a handle, which can drive the piston rod and the rubber stopper to move in the sample chamber.

[0017] According to one embodiment, the exhaust valve is provided with a porous breathable membrane to allow gas to escape and prevent liquid from escaping, so as to balance the pressure in the sample chamber.

[0018] According to one embodiment, the thickness of the sealing ring is between 1 mm and 2 mm.

[0019] According to one embodiment, a transparent viewing window is installed on the side wall of the sample chamber for observing the sample condition.

[0020] This disclosure provides a combined sampler for chemical testing, comprising: a sampling needle for inserting into a reaction vessel and extracting a liquid sample to be tested; a sample chamber connected to the sampling needle; a sealing ring located between the sampling needle and the sample chamber; and an exhaust valve disposed at the upper end of the sample chamber for balancing the pressure within the sample chamber to facilitate sample extraction and injection. The sampling needle has a spiral flow channel; the end of the sampling needle has a smooth, tapering structure; the outer wall of the sampling needle has an annular groove filled with an elastic sealing material; and the sampling needle contains multiple flow dividers, which are spaced apart along the spiral flow channel. This disclosure solves the problem of preventing sample stratification or uneven mixing. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the exemplary embodiments of this disclosure, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this disclosure and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of a combined sampler for chemical testing according to the present invention;

[0023] Figure 2This is a schematic diagram of the internal structure of the sampling needle in a combined sampler for chemical testing according to the present invention;

[0024] Figure 3 This is a schematic diagram of the internal structure of the sample chamber in a combined sampler for chemical testing as described in this utility model;

[0025] Figure 4 This utility model describes a combined sampler for chemical testing. Figure 3 Enlarged view of point A in the middle.

[0026] In the diagram: 1. Sampling needle; 11. Spiral flow channel; 12. Smooth tapering structure; 13. Annular groove; 14. Flow divider; 2. Sample chamber; 21. Rubber stopper; 22. Piston rod; 23. Transparent window; 24. Handle; 3. Sealing ring; 4. Exhaust valve; 41. Porous breathable membrane Detailed Implementation

[0027] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings.

[0028] The following specific examples illustrate the implementation of this disclosure. Those skilled in the art can easily understand other advantages and effects of this disclosure from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. This disclosure can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this disclosure. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0029] like Figure 1 As shown, a combined sampler for chemical testing according to this application includes four main components: a sampling needle 1, a sample chamber 2, a sealing ring 3, and an exhaust valve 4. The sampling needle 1, as the front-end sampling component, adopts a hollow tubular structure with an axially extending spiral flow channel 11 inside. This flow channel is precision-machined into a continuous threaded groove structure, for example, by spiral wire cutting using a CNC machine tool, ensuring a stable laminar flow state as the fluid passes through. The end of the sampling needle 1 is designed as a smooth tapered structure 12. This structure is formed into a tapered transition section with a gradually decreasing diameter through a multi-stage CNC turning process, with the taper angle controlled within the range of 15°-25° to ensure a smooth transition in flow velocity when the fluid enters the sampling needle 1.

[0030] The sample chamber 2 is a cylindrical sealed container, connected to the end of the sampling needle 1 via a flange. The inner surface of the chamber is mirror-polished. A three-way connector is located at the top of the chamber; one side connects to the sampling needle 1 via a quick-release clamp, and the other side is fitted with a one-way exhaust valve 4. The sealing ring 3 is molded from fluororubber material with a double-lip cross-section. It is fitted between the mating surfaces of the sampling needle 1 and the sample chamber 2, achieving radial compression sealing through an interference fit, with the compression controlled within the range of 0.2-0.5 mm. The exhaust valve 4 is a miniature solenoid valve with a built-in pressure sensor. It automatically opens to release air when the pressure inside the chamber exceeds a set threshold; for example, the valve opens when the pressure reaches 0.05 MPa and automatically closes when the pressure drops to atmospheric pressure.

[0031] This technical solution addresses sample stratification through multi-dimensional structural optimization: the spiral flow channel 11 transforms traditional straight flow into controlled spiral motion, effectively reducing the Reynolds number and maintaining laminar flow (Re < 2000). For example, at a sampling velocity of 0.5 m / s, the spiral flow channel can reduce turbulence intensity by more than 40%. The tapered needle, through its streamlined design, prevents eddy separation at the inlet; experiments show that this structure can reduce the inlet velocity gradient by approximately 30%. The silicone rubber material filled in the annular groove 13 forms an elastic sealing layer, and its surface micro-protrusions can create a slight disturbance to the boundary layer flow. PIV testing shows that this design can increase the near-wall velocity by 15%, effectively preventing component segregation caused by boundary layer retention. Combined with the intelligent pressure regulation function of the exhaust valve 4, the entire system can achieve pressure balance within 1.5 seconds, ensuring that the fluid remains in a steady-state flow during sampling. Spectroscopic analysis verifies that this can improve sample homogeneity to over 98.7%.

[0032] In the combined sampler for chemical testing, the helical angle of the spiral channel 11 is limited to 30° to 45°. This parameter range was determined through fluid dynamics simulation and experimental verification, aiming to balance the axial propulsion efficiency and circumferential shear effect of the liquid within the channel. The spiral channel 11 is formed on the inner surface of the sampling needle 1, with its continuous thread structure extending along the axis of the sampling needle 1. The inlet end smoothly transitions to the smoothly tapering structure 12, and the outlet end remains coaxially connected to the sample chamber 2. By controlling the tangent of the helical angle, the fluid generates appropriate rotational kinetic energy as it flows through the sampling needle 1, avoiding both increased flow resistance due to excessively small angles and secondary flow separation caused by excessively large angles. The channel cross-section adopts a near-elliptical design, with the major axis aligned with the helical tangent direction, further enhancing the guiding effect on the flow direction.

[0033] like Figure 2As shown, in one embodiment, the spiral flow channel 11 of a combined sampler for chemical testing according to this application is formed on the inner wall of the sampling needle 1 by precision machining. The spiral angle is specifically set to 38°±2°, and the thread lead is 1.8 times the inner diameter of the sampling needle 1. The flow channel starts at the beginning position of the smoothly tapering structure 12 at the end of the sampling needle 1 and extends axially along the sampling needle 1 to the connection end with the sample chamber 2. The depth of the flow channel is gradually adjusted according to the wall thickness of the sampling needle 1, ensuring the continuity of the flow channel cross-section while maintaining structural strength. Specifically, a five-axis CNC machine tool is used to machine the spiral groove in the inner hole of the sampling needle 1, followed by electrolytic polishing to control the surface roughness of the flow channel to within Ra0.4μm.

[0034] In the field of chemical testing, the hydrodynamic characteristics of the sampling needle 1 directly affect the sample collection quality. To solve the sample stratification problem caused by abrupt changes in cross-section at the tip of traditional needles, this application adopts a tapered flow channel design, achieving hydrodynamic control through geometric optimization. The axial profile of this tapered structure is modeled using a continuously differentiable curve equation, ensuring that the fluid cross-sectional area monotonically decreases along the flow direction. The ratio of the tapered section length to the inlet diameter is controlled within the range of (3:1)-(10:1), forming a sufficiently long transition region to reduce the fluid shear rate. The surface roughness Ra value of the structure does not exceed 0.8 μm, and CNC precision machining ensures geometric accuracy, with the end inner diameter tolerance controlled within ±0.05 mm. This structure has been verified through finite element fluid simulation, maintaining a stable laminar flow state under Reynolds number Re < 2000.

[0035] like Figure 2 As shown, in one embodiment, the sampling needle 1 of a combined sampler for chemical testing according to this application has a smooth tapered structure 12 formed at its end by precision turning. This tapered section extends outward from the end of the main body of the sampling needle 1, and its inner diameter continuously decreases axially from the main body flow channel diameter D0 to the minimum inner diameter D1 at the end. The cone angle is controlled within the range of 5°-15°, and the cone surface smoothly transitions to the main body flow channel through a curved surface. The tapered section is made of 316L stainless steel and is laser welded to form an integral structure with the main body of the sampling needle 1. Specifically, the tapered section is 15mm long, with an initial inner diameter of 3mm, gradually decreasing to an inner diameter of 1.2mm at the end according to a linear change law, and the surface is electrolytically polished. The tapered section and the internal spiral flow channel 11 form a continuous flow path system, and the chamfered edge at the end opening forms a smooth edge, effectively reducing fluid separation.

[0036] like Figure 2As shown, in one embodiment, the elastic sealing material filling the annular groove 13 of the combined sampler for chemical testing in this application is silicone rubber. This material is precision molded into an annular sealing component, the diameter of which is proportional to the depth of the annular groove 13, and is embedded inside the groove via an interference fit. The Shore hardness of the silicone rubber material is controlled within the range of 50A to 60A, and it produces uniform radial deformation during axial compression, ensuring the compression ratio is precisely maintained within the range of 20% to 30%. This compression ratio is determined through finite element simulation optimization, ensuring that the contact pressure of the sealing surface reaches the critical sealing threshold while avoiding material stress relaxation failure due to excessive compression. The axial end face of the sealing component has a trapezoidal cross-section flange, forming a double sealing interface with the mating surface of adjacent components, further enhancing sealing reliability.

[0037] Specifically, the annular groove 13 is precision machined to form a U-shaped cross-section, and an anti-rotation positioning boss is set at the bottom of the groove. The silicone rubber sealing component is prefabricated into an annular body with a positioning notch through injection molding. During assembly, it is embedded into the groove through a thermal expansion and contraction process, and a stable interference fit is formed after the temperature recovers. During the docking process between the sampling needle 1 and the sample chamber 2, the sealing component is subjected to axial compression, resulting in a predetermined deformation. The amount of compression is mechanically constrained by the limiting step structure to ensure that the compression ratio is always within the design range. For example, when the outer diameter of the sampling needle 1 is 8mm, the depth of the annular groove 13 is designed to be 3mm. After assembly, the actual compression of the silicone rubber sealing component is controlled between 0.6-0.9mm, corresponding to a compression ratio of 20%-30%.

[0038] like Figure 2 As shown, in one embodiment, a plurality of flow dividers 14 are added inside the sampling needle 1 of a combined sampler for chemical testing according to this application. The flow dividers 14 are axially spaced along the existing spiral flow channel 11, and their radial cross-section has an arc-shaped structure matching the flow channel profile. They are fixed to the inner wall of the flow channel by welding or integral molding. Each flow divider 14 is arranged at equal angular intervals along the spiral path, forming a continuous fluid guiding unit. Its thickness gradually decreases along the fluid direction to reduce flow resistance. The sub-channels formed between adjacent flow dividers 14 are connected by curved surface transitions, allowing the liquid flow to generate multi-level velocity gradient reconstruction while maintaining the spiral motion trajectory. The front edge of the flow divider 14 is rounded and forms a smooth transition connection with the inner wall of the flow channel to avoid the generation of local eddies. This structure guides the movement direction of fluid particles in stages, extending the effective stroke of the fluid in the spiral flow channel, thereby achieving a stepped dissipation of turbulent energy.

[0039] In practice, axially arranged positioning grooves can be pre-machined on the inner wall of the spiral flow channel 11. The thin-walled metal diverter plates 14, precision-stamped, are then embedded into these grooves and fixed using laser welding. For example, 0.2mm thick 316L stainless steel sheets can be machined into airfoil sections and arranged at 15° intervals along the spiral angle of the flow channel. The installation angle of each diverter plate 14 is offset by 3-5° relative to the flow channel axis to form a guiding angle. The surface of the diverter plate 14 is electrolytically polished, and its end extends to the starting position of the smooth tapering structure 12 at the end of the sampling needle 1, ensuring the continuous stability of the flow field within the flow channel. The filling process of the elastic sealing material in the annular groove 13 adopts a segmented injection molding method to avoid thermal stress affecting the fixing structure of the diverter plate 14.

[0040] A rubber stopper 21 is disposed inside the sample chamber 2, and the rubber stopper 21 is rigidly connected to one end of the piston rod 22 by axial fixation. The other end of the piston rod 22 extends to the outside of the sample chamber 2 and integrates a handle 24. The rod body passes through the guide hole at the end cap of the chamber and is clearance-fitted with the hole wall, thus forming a linear reciprocating motion mechanism. The outer edge of the rubber stopper 21 is interference-fitted with the inner wall of the sample chamber 2 to ensure that the airtight state is maintained during axial movement. The stroke range of the handle 24 is limited by the mechanical interference between the end cap of the chamber and the limiting boss of the rod body, thereby limiting the effective range of negative pressure generation. When the operator pulls the handle 24 outward, the piston rod 22 pulls the rubber stopper 21 to move outward from the chamber. At this time, the volume of the chamber in front of the rubber stopper 21 increases, forming a negative pressure area. This negative pressure is transmitted to the front end of the sampling needle 1 through the connecting pipe, driving the liquid to be tested to enter the chamber for storage along the internal channel of the sampling needle 1.

[0041] like Figure 3 As shown, in one embodiment, the rubber stopper 21 of the combined sampler for chemical testing in this application is molded from fluororubber, and its end face is provided with an annular sealing flange to enhance the contact pressure with the inner wall of the chamber. The piston rod 22 is machined from a thin stainless steel rod, and the middle of the rod body is provided with an axial scale mark to indicate the amount of pulling displacement. The handle 24 is designed as a T-shaped grip and is connected to the end of the piston rod 22 by a threaded fastening method. An oil-impregnated bearing is embedded in the guide hole, which reduces the coefficient of friction of the piston rod 22 movement and maintains the accuracy of the linear movement of the rod body. Specifically, when the handle 24 is pulled to the maximum stroke, the rubber stopper 21 moves to a predetermined position in the rear section of the chamber. At this time, the limiting boss contacts and locks with the end cap to ensure that the negative pressure value is stable within the set range.

[0042] In chemical testing and sampling, the pressure balance within sample chamber 2 directly affects sampling efficiency and sample integrity. To achieve efficient gas discharge and simultaneously prevent liquid leakage, a porous permeable membrane 41 is integrated inside the exhaust valve 4. This permeable membrane is vertically arranged in the middle of the exhaust channel, and its pore size distribution is precisely controlled to form a selective permeation barrier, allowing gas molecules to pass through the membrane layer along the diffusion gradient and be discharged, while the liquid surface tension and capillary action are effectively suppressed by the membrane structure. The outer edge of the permeable membrane is fixed to the inner wall of the valve body through an annular sealing component, forming an airtight isolation interface, while a support frame is embedded on both sides of the membrane layer to enhance structural rigidity. The membrane material is selected from hydrophobic polymers or inorganic composite materials to further enhance droplet retention capacity and avoid sample residue or contamination.

[0043] like Figure 3 and Figure 4 As shown, in one embodiment, the exhaust valve 4 of a combined sampler for chemical testing according to this application achieves directional gas discharge through a porous permeable membrane 41. Specifically, the porous permeable membrane 41 is sandwiched between two perforated metal support meshes, integrally embedded in the internal cavity of the valve body, and formed into an integrated sealed connection with the valve body through a hot-melt injection molding process. The support mesh is laser-cut from 316L stainless steel, with a perforation rate of not less than 60%, ensuring mechanical strength while reducing airflow resistance. The permeable membrane is made of polytetrafluoroethylene material prepared by a biaxial stretching process, with an average pore size controlled in the range of 0.1-0.5 micrometers and a membrane thickness of 50-100 micrometers. A silicone rubber sealing ring is set around the membrane layer, which is pressed into the groove on the inner wall of the valve body through an interference fit to form a double sealing interface. This structure allows air to be discharged quickly when sampling under negative pressure in the chamber, while when the liquid surface contacts the bottom of the valve body, the hydrophobic membrane layer can immediately block liquid penetration.

[0044] In the combined sampler used for chemical testing, the sealing ring 3, as a key sealing element, is located in the transition area connecting the sampling needle 1 and the sample chamber 2. This sealing ring 3 is made of perfluororubber-based chemical-resistant material, whose chemical inertness allows it to withstand the erosion of strong acids, strong alkalis, and organic solvents, preventing swelling or structural failure due to media penetration. The thickness of the sealing ring 3 is designed to be between 1mm and 2mm. This size range meets the requirements for elastic deformation while also considering mechanical support strength, compensating for gaps caused by assembly tolerances, and withstanding repeated hydraulic pulsation impacts during sampling. By optimizing the matching relationship between thickness parameters and material hardness, the contact surface pressure can be maintained within a suitable range of 0.3-0.6MPa, ensuring both static sealing effect and preventing permanent deformation caused by overload compression. The sealing ring 3 has a rectangular or trapezoidal cross-section and is embedded in the mounting groove through an interference fit. Its radial compression ratio is controlled between 15% and 25% to balance sealing performance and service life.

[0045] In one embodiment, the sealing ring 3 of a combined sampler for chemical testing according to this application is formed into a ring-shaped solid structure by turning. During assembly, it is embedded in the annular gap between the outer wall of the sampling needle 1 and the inner wall of the inlet of the sample chamber 2. Specifically, the sealing ring 3 is injection molded from perfluororubber material with a thickness of 1.5 mm. Its inner diameter maintains an interference fit of 0.2 mm with the outer diameter of the sampling needle 1, and its outer diameter forms a compression allowance of 0.3 mm with the inner wall of the inlet of the sample chamber 2. During installation, a heat fitting process is used. The sealing ring 3 is heated to 120°C and then fitted onto the pre-set positioning step of the sampling needle 1. After cooling, a stable radial clamping force is formed. A pre-compression gap of 0.8 mm is set between the axial end face of the sealing ring 3 and the inlet end face of the sample chamber 2. The axial pressure generated by tightening the flange bolts achieves auxiliary sealing of the end face.

[0046] In chemical testing and sampling, real-time monitoring of sample status is crucial for ensuring testing accuracy. This application addresses this issue by incorporating a transparent viewing window 23 on the side wall of the sample chamber 2, allowing the operator to directly observe changes in the physical state of the sample within the chamber. This transparent viewing window 23 extends axially along the chamber, covering the main body of the chamber, and its installation height corresponds to the typical sampling liquid level range. The window is made of a corrosion-resistant, high-transmittance material, and its surface is treated with an anti-glare coating to avoid optical interference. To adapt to different process environments, a removable protective cover can be fitted to the outside of the window to prevent damage to the observation interface from chemical splashes or mechanical impacts. The window edge employs an embedded mounting structure, forming a redundant seal with the chamber wall through double sealing strips, ensuring airtightness under high pressure or vacuum conditions.

[0047] like Figure 1 As shown, in one embodiment, the transparent window 23 of a combined sampler for chemical testing according to this application can be implemented in the following way: a rectangular observation window is embedded in a reserved opening in the side wall of the sample chamber 2, fixed by a flange-type compression structure, and a fluororubber sealing ring 3 is provided between the window and the chamber body. The window is then circumferentially tightened with evenly distributed bolts. Specifically, the window is made of 8mm thick borosilicate glass, with its light-transmitting area covering 1 / 2 to 2 / 3 of the total height of the chamber. Both ends are chamfered at 45° to avoid stress concentration. During installation, the sealing ring 3 is first pre-installed in the stepped groove of the chamber opening, then the window is aligned with the positioning pin and inserted, and finally, a stainless steel flange and a PTFE gasket are used for compression sealing. This structure allows for real-time observation of sample turbidity changes and the position of the liquid-liquid interface during sampling.

[0048] In actual operation, when this device is used, the sampling needle 1 is first inserted into the reaction vessel. Its smooth tapering structure 12 at the end reduces the flow resistance at the sample inlet and avoids stratification. At the same time, the elastic sealing material in the annular groove 13 on the outer wall adheres to the container wall to form a dynamic seal. As the liquid sample is drawn through the spiral flow channel 11 inside the sampling needle 1, the spiral design of the flow channel effectively reduces the turbulence effect of the liquid flow, allowing the sample to enter the sample chamber 2 smoothly. During this process, the sealing ring 3 continuously maintains the sealing state at the connection between the sampling needle 1 and the sample chamber 2, and the operator can open the exhaust valve 4 in time to adjust the internal pressure of the chamber to ensure that the sample is smoothly injected into the storage space. After sampling is completed, the exhaust valve 4 is closed to maintain the chamber seal, ultimately achieving efficient and stable sample collection and preservation.

[0049] The specific embodiments described above further illustrate the purpose, technical solutions, and beneficial effects of the embodiments of this disclosure. It should be understood that the above descriptions are merely specific embodiments of the embodiments of this disclosure and are not intended to limit the scope of protection of the embodiments of this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this disclosure should be included within the scope of protection of the embodiments of this disclosure.

Claims

1. A combined sampler for chemical testing, characterized in that, include: Sampling needle (1) is used to insert into the reaction vessel and extract the liquid sample to be tested; The sample chamber (2) is connected to the sampling needle (1); A sealing ring (3) is located between the sampling needle (1) and the sample chamber (2); An exhaust valve (4) is located at the upper end of the sample chamber (2) to balance the pressure inside the sample chamber (2) for sample extraction and injection; wherein: The sampling needle (1) is provided with a spiral flow channel (11); The sampling needle (1) has a smooth tapered structure (12) at its end; The outer wall of the sampling needle (1) is provided with an annular groove (13), and the annular groove (13) is filled with elastic sealing material; The sampling needle (1) is provided with multiple flow dividers (14) inside, and the multiple flow dividers (14) are distributed at intervals along the spiral flow channel (11).

2. The combined sampler for chemical testing according to claim 1, characterized in that: The spiral angle α of the spiral flow channel (11) is 30° to 45° to optimize the flow path.

3. The combined sampler for chemical testing according to claim 1, characterized in that: The diameter of the end of the smooth tapering structure (12) gradually decreases, with a minimum inner diameter of 5 mm to 1 mm, to prevent the sample from stratifying at the needle inlet.

4. The combined sampler for chemical testing according to claim 1, characterized in that: The elastic sealing material filling the annular groove (13) is made of silicone rubber, and its compression ratio is maintained at 20% to 30%.

5. A combined sampler for chemical testing according to claim 1, characterized in that: A rubber stopper (21) is provided in the sample chamber (2). One end of the rubber stopper (21) is connected to a piston rod (22). The end of the piston rod (22) away from the rubber stopper (21) is connected to a handle (24). The handle (24) can drive the piston rod (22) and the rubber stopper (21) to move in the sample chamber.

6. A combined sampler for chemical testing according to claim 1, characterized in that: The exhaust valve (4) is provided with a porous breathable membrane (41) to allow gas to be discharged and to prevent liquid from escaping, so as to balance the pressure in the sample chamber (2).

7. A combined sampler for chemical testing according to claim 1, characterized in that: The thickness of the sealing ring (3) is between 1 mm and 2 mm.

8. A combined sampler for chemical testing according to claim 1, characterized in that: A transparent viewing window (23) is installed on the side wall of the sample chamber (2) for observing the sample.

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