Small-volume high-efficiency online static mixer applicable to ultra-high performance liquid chromatography system

Abstract

A small-volume high-efficiency on-line static mixer applicable to an ultra-high performance liquid chromatography system, comprising a number of columnar inner cores. Axial liquid inlet holes and liquid outlet holes are respectively formed in the middle of the upper and lower end faces of the inner cores. A certain number of first connection holes and second connection holes radially distributed are respectively formed in the upper and lower positions of the side walls of the inner cores. The inner ends of the first connection holes communicate with the inner ends of the liquid inlet holes, and the inner ends of the second connection holes communicate with the inner ends of the liquid outlet holes. A first annular groove is formed in the side wall of the inner core where the outer ends of the first connection holes are located, and a second annular groove is formed in the side wall of the inner core where the outer ends of the second connection holes are located. A certain number of connection grooves are formed in the side wall of the inner core between the first annular groove and the second annular groove. The mixer of the present invention is small in volume, takes into account both binary high-pressure gradient systems (radial mixing) and low-pressure gradient systems (time front-back mixing), and can be applicable to both HPLC systems and UHPLC systems at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of mixer structures, and particularly to a small-volume high-efficiency on-line static mixer applicable to an ultra-high performance liquid chromatography system. Background Art

[0002] Currently, common high-performance liquid chromatography (HPLC) and ultra-high performance liquid chromatography (UHPLC) both include isocratic mode and gradient mode.

[0003] In the isocratic mode, the infusion system is only responsible for delivering a single-component mobile phase, while in the gradient mode, the infusion system needs to transport two or more mobile phases, and during use, the composition ratio of each mobile phase needs to change with time. To ensure the separation and analysis effect, multiple mobile phases need to be fully mixed before entering the chromatographic column to avoid affecting the peak shape and reproducibility of the sample peaks.

[0004] However, whether it is a binary high-pressure gradient system using two infusion pumps or a quaternary low-pressure gradient system using a proportioning valve for preliminary mixing, different mobile phases are placed in different solvent bottles before entering the system. That is to say, for a gradient system, between the infusion system and the injection system, an on-line mixer is required to fully mix the mobile phases before entering the chromatographic column. Moreover, for the real-time nature of the ratio change, on the premise of ensuring the mixing effect, the volume of this on-line mixer must be small enough, because after the composition of the mobile phase changes, the liquid in the mixer needs to be replaced first before reaching the chromatographic column.

[0005] The commonly used analysis flow rate of HPLC is 1000 - 2000 μL / min, while the commonly used flow rate of the UHPLC system is below 500 μL / min, and most of the chromatographic columns used in the UHPLC system have a smaller volume and the sample peak elution time is shorter. The volume of the mixer in the current HPLC systems on the market is generally 1000 - 3000 μL. This kind of mixer's lag volume is acceptable for the HPLC system, but it is not applicable to the UHPLC system. When injecting samples in gradient mode, it is very likely that the sample peak has eluted before the change in the composition of the mobile phase reaches the chromatographic column. Therefore, the volume of the mixer applicable to UHPLC must be further reduced based on the current HPLC mixer.

[0006] In addition, from fluid mechanics, it is known that the best way to improve the liquid mixing efficiency is to bring the mobile phase into a turbulent state. The commonly used pipe diameter in HPLC is 0.5 mm; the commonly used pipe diameter in UHPLC is 0.25 mm, both of which belong to microchannels. In microchannels, the liquid viscous force plays a dominant role and the Reynolds number is very small. For example, calculated according to the commonly used conditions of HPLC (pure water, 20 °C, flow rate 1000 μL / min, pipe diameter 0.5 mm), the Reynolds number Re = 42 is obtained; calculated according to the commonly used conditions of UHPLC (pure water, 20 °C, flow rate 430 μL / min, pipe diameter 0.25 mm), the Reynolds number Re = 36 is obtained. Both are less than the critical value of turbulence. Therefore, the fluid state in the pipeline of the liquid chromatography system can basically be considered laminar flow.

[0007] For the mixing of different mobile phases, it mainly relies on intermolecular diffusion in the laminar flow state. Therefore, to improve the mixing effect of the fluid in the laminar flow state, on the one hand, we need to increase the contact area between different mobile phases, that is, to perform multiple shunting and merging of the mobile phases; on the other hand, we need to create special mixing conditions, such as impact, baffle, spiral coil, etc. to enhance the local mixing effect.

[0008] Finally, in the binary high-pressure gradient system and the quaternary low-pressure gradient system, the distribution methods of different mobile phases in the pipeline are different. The binary high-pressure system uses two separate infusion pumps (similarly, there are also ternary and quaternary high-pressure systems, which will not be elaborated here) to transport different mobile phases, and the outlet of each pump is connected to a pre-mixer (a tee is generally used in the binary system) to converge all mobile phases into the same flow path. That is to say, in the binary high-pressure system, at a certain moment of the cross-section of the merged pipeline, there are two different mobile phases at the same time. However, for the quaternary low-pressure gradient system (similarly, it also applies to other multi-component systems controlled by electromagnetic proportional valves), it has only one infusion pump, and different mobile phases enter the system at different times through the switching of the solenoid valve. At a certain moment of the cross-section of the pipeline at the outlet of the infusion pump, there is only one mobile phase. For this way of mixing, the time factor needs to be introduced, and the mobile phases need to be mixed front and back. Summary of the Invention

[0009] The object of the present invention is to solve the deficiencies of the above-mentioned existing devices, taking into account both the binary high-pressure gradient system and the low-pressure gradient system, and provide a small-volume and high-efficiency online static mixer applicable to the ultra-high performance liquid chromatography system.

[0010] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0011] A small-volume high-efficiency on-line static mixer applicable to an ultra-high performance liquid chromatography system, comprising a number of columnar inner cores. Axial liquid inlet holes and liquid outlet holes are respectively formed in the middle of the upper and lower end faces of the inner cores. A certain number of first connection holes and second connection holes radially distributed are respectively formed in the upper and lower positions of the side wall of the inner core. The inner end of the first connection hole communicates with the inner end of the liquid inlet hole, and the inner end of the second connection hole communicates with the inner end of the liquid outlet hole. A first annular groove is formed in the side wall of the inner core where the outer end of the first connection hole is located, and a second annular groove is formed in the side wall of the inner core where the outer end of the second connection hole is located. A certain number of connection grooves are formed in the side wall of the inner core between the first annular groove and the second annular groove. The liquid is first split when flowing from the liquid inlet hole to the first connection hole, dividing the fluid into multiple portions. Then the liquid enters the first annular groove, and the already split liquid is split again when entering the first annular groove. The liquid in each first connection hole is split into two. The liquid in the first annular groove converges into the connection groove, and then enters the second annular groove flow path. The liquid is split when entering the second annular groove, and then the liquid enters the second connection hole. The liquid converges when entering the second connection hole, and finally the liquid converges again and enters the liquid outlet hole. Inside the inner core of the mixer, from the inlet to the outlet, the liquid undergoes 9 splits and 9 merges, and there are 9 T-shaped impacts.

[0012] Preferably, the number of the first connection holes and the second connection holes is even and they are equidistantly distributed. The number of the first connection holes and the second connection holes can be 4, 6, 8, etc.

[0013] Preferably, the number of the first connection holes, the second connection holes and the connection grooves is the same.

[0014] Preferably, the cross sections of the liquid inlet hole, the liquid outlet hole, the first connection hole and the second connection hole are circular, and the cross sections of the first annular groove, the second annular groove and the connection groove are semi-circular.

[0015] Preferably, the connection groove is an axial straight groove, or an inclined or curved inclined groove. If the connection groove is an axial straight groove, when entering the connection groove from the first annular groove, it can be approximated as a T-shaped groove, with the 90° direction being the outlet. Different mobile phases collide at 180° in the T-shaped structure. After the collision, the cross-sectional molecules of the opposite fluids are exchanged. Due to the opposite velocity directions of the two colliding fluids, the mixing effect of the collision is much higher than that of ordinary confluence. If the connection groove is an inclined or curved (such as a spiral) inclined groove, the engraved flow path naturally has curvature, causing a centrifugal force when the liquid flows on the surface of the inner core, generating a secondary flow perpendicular to the main flow direction, improving the radial mixing effect of the mobile phase. Originally, the secondary flow only existed in the annular groove, but after changing the connection groove to an inclined groove, there is also a secondary flow on the inclined groove, prolonging the existence time of the secondary flow, which is beneficial to the radial mixing of the fluid in the pipeline.

[0016] Preferably, the inner core is made of resin material, such as PEEK.

[0017] Preferably, the mixer includes a stainless - steel outer shell. Inside the stainless - steel outer shell, there are two inner cores distributed in series up and down. Connection end - caps are provided at both the upper and lower ends respectively, and connection holes are provided on the connection end - caps. The inner cores made of PEEK material are installed in the stainless - steel outer sleeve at low temperature (minus 40 °C). After installation, when the temperature returns to normal, the PEEK inner cores expand to fit perfectly with the stainless - steel outer sleeve.

[0018] Preferably, a gasket is provided between the connection end - cap and the stainless - steel outer shell, and a perforated partition is provided between the two inner cores. The partition can be an integral structure with the stainless - steel outer shell, which is equivalent to drilling holes inside the stainless - steel outer sleeve and sealing both ends, reducing the liquid leakage points.

[0019] Preferably, the mixer further includes a stainless - steel outer shell. Inside the stainless - steel outer shell, there are at least two inner cores distributed in series. A connection end - cap is provided at the upper end of the stainless - steel outer shell, and a connection hole is provided at the lower end.

[0020] Preferably, a perforated spacer is provided between the inner cores. The spacer is made of elastic materials (such as PTFE, PEEK, etc.), which reduces the processing difficulty of the flow path and is more conducive to combining different inner cores to meet different mixing requirements.

[0021] Preferably, the mixer further includes a stainless - steel outer shell. A certain number of accommodation holes are provided on the upper end - face of the stainless - steel outer shell. Inner cores are respectively provided in the accommodation holes, and connection end - caps with gaskets are provided at the ends. The inner cores of the mixer are connected in parallel, and the number is two or more. By using the parallel connection method, on the one hand, the linear velocity of the mobile phase entering the inner cores can be reduced, and the molecular diffusion time can be prolonged; on the other hand, the mixed liquid is divided into smaller volume units, which can increase the specific surface area and improve the mixing effect of intermolecular diffusion. If inner cores with different flow - path volumes but the same resistance are selected in the parallel connection method, a phase difference can be created to achieve front - back mixing. And due to the relationship of one - in - to - multiple at the inlet, compared with the series connection method, the volume difference required to create an equivalent phase difference is smaller, which is beneficial to reducing the overall volume of the mixer.

[0022] Preferably, the number of the connection end - caps is one. A certain number of upper connection holes communicating with the accommodation holes are provided at the bottom, and the upper connection holes incline towards the middle and coincide on the top surface. Lower connection holes are respectively provided on the stainless - steel outer shell at the bottom of the accommodation holes, and the lower connection holes incline towards the middle and coincide on the bottom surface.

[0023] Preferably, stainless - steel tubes are welded respectively at the outer ends of the upper connection holes of the connection end - cap and the outer ends of the lower connection holes of the stainless - steel outer shell. The stainless - steel tubes are used for connecting with the infusion system. The welding method for the outlet and inlet pipelines can reduce the use of external pipeline joints, that is, reduce the liquid leakage points.

[0024] Preferably, the number of the connecting end caps is one or more, and axially extending upper connection holes communicating with the accommodation holes are formed therein. Axially extending lower connection holes are respectively formed in the stainless steel outer shell at the bottom of the accommodation holes. The upper connection holes and the lower connection holes are then communicated with the infusion system through multi-way pipelines with a number one more than their own number.

[0025] The beneficial effects of the present invention are as follows: 1. The mixer of the present invention is small in volume, taking into account both the binary high-pressure gradient system (radial mixing) and the low-pressure gradient system (front and back mixing in time), and can be applicable to both HPLC systems and UHPLC systems;

[0026] 2. The flow path is engraved on the surface of the inner core cylinder. When flowing, there is a centrifugal force, generating a secondary flow, which can perform radial mixing, facilitating the mixing of different mobile phase systems in the pipeline cross-section simultaneously (typically such as a binary high-pressure gradient system). One implementation method is to extend the surface connection flow path to make the pipeline into a spiral, extending the existence time of the secondary flow and strengthening the radial mixing effect;

[0027] 3. The fluid is shunted and merged multiple times in the core. The structure of a typical example (Example 1) has undergone 9 shunts and 9 merges;

[0028] 4. The T-shaped groove is adopted, and the two-way liquids impact against each other, enhancing the mixing effect;

[0029] 5. The diameter of the PEEK inner core and the radius of the notch can be changed separately. For example, the connection traces between the upper circumference and the lower circumference adopt notches with different inner diameters, lengths, and shapes, making the flow path volumes unequal. When the liquids converge at the outlet, there will be a time phase difference, and the mobile phases are mixed front and back, facilitating the mixing effect of different mobile phase compositions in the flow direction (such as a low-pressure gradient system);

[0030] 6. The combination mode of the PEEK inner core and the stainless steel outer sleeve is adopted. The length and number of the inner cores can be increased or decreased, and the series connection method or the parallel connection method can be used, with quite high flexibility;

[0031] 7. In some cases, the welding method is used for parallel connection, and the sealing ring is used for sealing during series connection, reducing the number of external stainless steel joints, that is, reducing the liquid leakage points of the system and having better pressure retention under high pressure.

[0032] 8. Small in volume. When all flow paths use notches with d = 0.5 mm (R = 0.25 mm), the volume of a single mixer core is only 20 μL, which can be fully applied to UHPLC systems. Description of the Drawings

[0033] Figure 1 is a perspective view of Embodiment 1 of the present invention;

[0034] Figure 2 is a front view of Embodiment 1 of the present invention;

[0035] Figure 3 is Figure 2 the sectional view taken along the A-A direction in

[0036] Figure 4 is Figure 2 the sectional view taken along the B-B direction in

[0037] Figure 5 the flowchart schematic of the first embodiment of the present invention;

[0038] Figure 6 is the perspective view of the second embodiment of the present invention;

[0039] Figure 7 is the front view of the second embodiment of the present invention;

[0040] Figure 8 is the perspective view of the third embodiment of the present invention;

[0041] Figure 9 is the front view of the third embodiment of the present invention;

[0042] Figure 10 is Figure 9 the sectional view taken along the C-C direction in

[0043] Figure 11 is the exploded view of the third embodiment of the present invention;

[0044] Figure 12 is the perspective view of the fourth embodiment of the present invention;

[0045] Figure 13 is the front view of the fourth embodiment of the present invention;

[0046] Figure 14 is Figure 13 the sectional view taken along the D-D direction in

[0047] Figure 15 is the exploded view of the fourth embodiment of the present invention;

[0048] Figure 16 is the perspective view of the fifth embodiment of the present invention;

[0049] Figure 17 is the front view of the fifth embodiment of the present invention;

[0050] Figure 18 is Figure 17 the sectional view taken along the E-E direction in

[0051] Figure 19 is the exploded view of the fifth embodiment of the present invention.

[0052] Description of the main component symbols in the figure: 10, inner core; 11, liquid inlet hole; 12, liquid outlet hole; 13, first connection hole; 14, second connection hole; 15, first annular groove; 16, second annular groove; 17, connection groove; 17', inclined groove; 20, stainless steel shell; 21, connection hole; 30, connection end cover; 40, gasket; 50, spacer; 60, stainless steel pipe. Detailed implementation mode

[0053] The present invention will be further described below through specific implementation modes and the accompanying drawings.

[0054] Example 1: As Figures 1-4 shown, a small-volume high-efficiency on-line static mixer applicable to an ultra-high performance liquid chromatography system includes a plurality of columnar inner cores 10 made of resin material (such as PEEK). Axial liquid inlet holes 11 and liquid outlet holes 12 are respectively opened in the middle of the upper and lower end faces of the inner core 10. Four radially distributed first connection holes 13 and second connection holes 14 are respectively opened at the upper and lower positions on the side wall of the inner core 10. The inner end of the first connection hole 13 communicates with the inner end of the liquid inlet hole 11, and the inner end of the second connection hole 14 communicates with the inner end of the liquid outlet hole 12. A first annular groove 15 is opened on the side wall of the inner core 10 where the outer end of the first connection hole 13 is located, and a second annular groove 16 is opened on the side wall of the inner core 10 where the outer end of the second connection hole 14 is located. Four connection grooves 17 are opened on the side wall of the inner core 10 between the first annular groove 15 and the second annular groove 16. Among them, the cross-sections of the liquid inlet hole 11, the liquid outlet hole 12, the first connection hole 13 and the second connection hole 14 are circular, the cross-sections of the first annular groove 15, the second annular groove 16 and the connection groove 17 are semi-circular, and the connection groove 17 is an axial straight groove.

[0055] Combined with Figure 5 shown, the liquid undergoes a total of 9 times of shunting and 9 times of confluence from the inlet to the outlet of the inner core 10, and there are 9 times of T-shaped impacts.

[0056] The liquid flow path is engraved on the inner core 10. The diameter of the inner core 10 and the radius of the engraving can be changed separately. For example, the connection flow paths between the upper circumference and the lower circumference adopt engravings with different inner diameters, lengths and shapes, so that there is a time phase difference in the mobile phase when it converges at the outlet, achieving the purpose of mixing the mobile phase before and after. The mixing before and after is mainly applicable to the quaternary low-pressure gradient, because the quaternary low-pressure gradient makes different mobile phases enter the system at different time periods by adopting the method of opening the solenoid valves corresponding to different mobile phases. At this time, the mixing uniformity depends more on the mixing before and after.

[0057] In this embodiment, the number of the first connection holes 13 and the second connection holes 14 can also be other even numbers. The number of the first connection holes 13, the second connection holes 14 and the connection grooves 17 is the same, and they are equally spaced.

[0058] Example 2: As Figures 6-7As shown, the difference from the first embodiment is that the connecting groove 17 is an inclined or curved inclined groove 17'. Originally, the secondary flow only existed in the first annular groove 15 and the second annular groove 16. After changing the connecting groove 17 to the inclined groove 17', there is also secondary flow on the inclined groove 17', extending the existence time of the secondary flow, which is beneficial to the radial mixing of the fluid in the pipeline.

[0059] Embodiment Three: As Figures 8-11 shown, it is applicable to the case where only two mixer cores 10 need to be connected in series. It includes a stainless-steel outer shell 20, with two cores 10 distributed in series up and down inside the stainless-steel outer shell 20, and connection end caps 30 are provided at the upper and lower ends respectively. A sealing gasket 40 is provided between the connection end cap 30 and the stainless-steel outer shell 20, and a perforated partition is provided between the two cores 10. Drilling holes directly inside the stainless-steel outer shell 20 and sealing both ends reduces the liquid leakage points and increases the system reliability.

[0060] Embodiment Four: As Figures 12-15 shown, it is applicable to the case where more than two mixer cores 10 are connected in series. It includes a stainless-steel outer shell 20, with at least two cores 10 distributed in series inside the stainless-steel outer shell 20. A connection end cap 30 is provided at the upper end of the stainless-steel outer shell 20, and a connection hole 21 is provided at the lower end. A perforated spacer 40 is provided between the cores 10. The spacer 40 is made of an elastic material (such as PTFE, PEEK, etc.).

[0061] When pressing the core 10 into the stainless-steel outer shell 20, apply a certain force to deform the spacer 40 and eliminate the gap between the two cores. For the installation of multiple cores 10, install them in the stainless-steel outer shell 20 in the order of core 10 → spacer 40 → core 10 → spacer 40 →... → spacer 40 → core 10, and finally install the connection end cap 30.

[0062] If installed in the traditional way, for n cores 10 connected in series, 2n pipeline connection positions are required, while according to the scheme shown in this embodiment, only 2 pipeline connection positions are needed, significantly reducing the liquid leakage points of the system and improving the system reliability.

[0063] Embodiment Five: As Figures 16-19 shown, it is applicable to the case where multiple mixer cores 10 are connected in parallel. It includes a stainless-steel outer shell 20, with a certain number of accommodation holes provided on the upper end face of the stainless-steel outer shell 20. Cores 10 are respectively provided in the accommodation holes, and a connection end cap 30 with a sealing gasket 40 is provided at the end.

[0064] Among them, the number of connecting end caps 30 is one, and a certain number of upper connecting holes communicating with the accommodating holes are provided at the bottom. The upper connecting holes incline towards the middle and coincide on the top surface. The stainless steel outer shell 20 at the bottom of the accommodating holes are respectively provided with lower connecting holes. The lower connecting holes incline towards the middle and coincide on the bottom surface. Stainless steel pipes 60 are respectively welded to the outer ends of the upper connecting holes of the connecting end cap 30 and the outer ends of the lower connecting holes of the stainless steel outer shell 20, reducing the use of external pipeline connectors, which can also reduce the sealing points, that is, reduce the liquid leakage points.

[0065] It should be noted that the stainless steel pipes 60 can also not be provided. The number of connecting end caps 30 is one or more, and axially arranged upper connecting holes communicating with the accommodating holes are formed thereon. The stainless steel outer shell 20 at the bottom of the accommodating holes are respectively provided with axially arranged lower connecting holes. The upper connecting holes and the lower connecting holes are then communicated with the infusion system through multi-way pipelines with the number of them plus one.

[0066] On the one hand, the parallel connection method can reduce the linear flow rate of the mobile phase entering each mixer, increase the contact time of different mobile phase molecules, and improve the mixing effect. On the other hand, since the mixed liquid is divided into smaller volume units, the specific surface area can be increased, and the mixing effect of intermolecular diffusion can be improved. If four inner cores 10 with different fluid volumes and the same resistance are used in the parallel connection method, a phase difference can be created to enable front-back mixing. Due to the relationship of one inlet dividing into multiple outlets, compared with the series connection method, the volume difference required to create an equivalent phase difference is smaller, which is beneficial to reducing the overall volume of the mixer. In the figure, only one divided into four is drawn for convenience of illustration. In fact, it can be one divided into two, one divided into eight. As long as the structure permits, it can be divided into any number of flow paths.

[0067] The above are only specific embodiments of the present invention, but the structural features of the present invention are not limited thereto. The present invention can be used on similar products. Any changes or modifications made by those skilled in the art within the scope of the present invention are covered by the patent scope of the present invention.

Claims

1. A small-volume high-efficiency on-line static mixer applicable to an ultra-high performance liquid chromatography system, comprising a number of columnar inner cores (10), characterized in that: Axial liquid inlet holes (11) and liquid outlet holes (12) are respectively formed in the middle of the upper and lower end faces of the inner core (10). A certain number of first connection holes (13) and second connection holes (14) radially distributed are respectively formed in the upper and lower positions of the side wall of the inner core (10). The inner end of the first connection hole (13) communicates with the inner end of the liquid inlet hole (11), and the inner end of the second connection hole (14) communicates with the inner end of the liquid outlet hole (12). A first annular groove (15) is formed in the side wall of the inner core (10) where the outer end of the first connection hole (13) is located, and a second annular groove (16) is formed in the side wall of the inner core (10) where the outer end of the second connection hole (14) is located. A certain number of connection grooves (17) are formed in the side wall of the inner core (10) between the first annular groove (15) and the second annular groove (16); The number of the first connection holes (13) and the second connection holes (14) is even and they are equidistantly distributed; The number of the first connection holes (13), the second connection holes (14) and the connection grooves (17) is the same.

2. The small-volume high-efficiency on-line static mixer applicable to an ultra-high performance liquid chromatography system according to claim 1, characterized in that: The cross-sections of the liquid inlet hole (11), the liquid outlet hole (12), the first connection hole (13) and the second connection hole (14) are circular, and the cross-sections of the first annular groove (15), the second annular groove (16) and the connection groove (17) are semi-circular.

3. The small-volume high-efficiency on-line static mixer applicable to an ultra-high performance liquid chromatography system according to claim 1, characterized in that: The connection groove (17) is an axial straight groove or an inclined or curved inclined groove (17’).

4. The small-volume high-efficiency on-line static mixer applicable to an ultra-high performance liquid chromatography system according to claim 1, characterized in that: The inner core (10) is made of resin material.

5. The small-volume high-efficiency on-line static mixer applicable to an ultra-high performance liquid chromatography system according to any one of claims 1-4, characterized in that: It further includes a stainless steel outer shell (20). Two inner cores (10) connected in series up and down are arranged in the stainless steel outer shell (20), and connection end caps (30) are respectively arranged at the upper and lower ends.

6. The small-volume high-efficiency on-line static mixer applicable to an ultra-high performance liquid chromatography system according to claim 5, characterized in that: A sealing gasket (40) is arranged between the connection end cap (30) and the stainless steel outer shell (20), and a partition with holes is arranged between the two inner cores (10).

7. The small-volume high-efficiency on-line static mixer applicable to an ultra-high performance liquid chromatography system according to any one of claims 1-4, characterized in that: It further includes a stainless steel outer shell (20). At least two inner cores (10) connected in series are arranged in the stainless steel outer shell (20). A connection end cap (30) is arranged at the upper end of the stainless steel outer shell (20), and a connection hole (21) is arranged at the lower end.

8. The small-volume high-efficiency on-line static mixer applicable to an ultra-high performance liquid chromatography system according to claim 7, characterized in that: A spacer (50) with holes is arranged between the inner cores (10).

9. The small-volume high-efficiency on-line static mixer applicable to an ultra-high performance liquid chromatography system according to any one of claims 1-4, characterized in that: It further includes a stainless steel outer shell (20). A certain number of accommodation holes are formed in the upper end face of the stainless steel outer shell (20). Inner cores (10) are respectively arranged in the accommodation holes, and a connection end cap (30) with a sealing gasket (40) is arranged at the end.

10. The small-volume high-efficiency on-line static mixer applicable to an ultra-high performance liquid chromatography system according to claim 9, characterized in that: The number of the connection end caps (30) is one. A certain number of upper connection holes communicating with the accommodation holes are formed at the bottom. The upper connection holes incline towards the middle and coincide on the top surface. Lower connection holes are respectively formed in the stainless steel outer shell (20) at the bottom of the accommodation holes. The lower connection holes incline towards the middle and coincide on the bottom surface.

11. The small-volume high-efficiency on-line static mixer applicable to an ultra-high performance liquid chromatography system according to claim 10, characterized in that: Stainless steel pipes (60) are respectively welded to the outer ends of the upper connection holes of the connection end cap (30) and the outer ends of the lower connection holes of the stainless steel outer shell (20).

12. The small-volume high-efficiency on-line static mixer applicable to an ultra-high performance liquid chromatography system according to claim 9, characterized in that: The number of the connection end caps (30) is one or more. Axial upper connection holes communicating with the accommodation holes are formed thereon. Axial lower connection holes are respectively formed in the stainless steel outer shell (20) at the bottom of the accommodation holes.

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