Tools for pre-fixing the chromatographic column to the graphite sleeve

Abstract

A tool for pre-fixing a chromatographic column to a graphite ferrule prevents undesirable axial movement of the column during installation into an injection module. The tool includes a tool body and a compression pre-tightening mechanism. The tool body has a positioning section for positioning the graphite ferrule through which the chromatographic column is inserted. The compression pre-tightening mechanism includes a force loading module and a pusher. The force loading module outputs a push force. The pusher is movably disposed in the tool body and has an elongated receiving hole for the chromatographic column passing through the graphite ferrule. The pusher receives the push force and applies an axial pre-tightening force to the graphite ferrule positioned at the positioning section.

Description

Technical Field

[0001] This utility model relates to the connection of chromatographic columns in gas chromatography analyzers, and more particularly to auxiliary tools for column installation. Background Technology

[0002] Gas chromatographs are the core equipment for the separation, qualitative and quantitative analysis of multi-component samples in the laboratory. They mainly consist of a separation section and an analysis section. The chromatographic column in the separation section is the key component for achieving the separation of sample components. The connection and installation performance between the chromatographic column and the injection module affects the stability and repeatability of gas chromatographic analysis results.

[0003] Currently, in the routine installation of chromatographic columns, the column, which has been inserted through a graphite ferrule, is manually inserted into the injection module. A wrench or similar tool is then used to tighten the nut connected to the injection module to compress the graphite ferrule, thereby securing the column.

[0004] The inventors discovered that during the installation and tightening of the chromatographic column, due to the gap between the inner hole of the ferrule and the chromatographic column, the chromatographic column is prone to axial movement relative to the ferrule, making it difficult to control the extension length of the chromatographic column relative to the ferrule. This is one of the reasons for the poor repeatability of chromatographic column installation and the instability of gas chromatography analysis results. Utility Model Content

[0005] The purpose of this invention is to provide a tool for pre-fixing a chromatographic column to a graphite sleeve, so as to prevent the chromatographic column from undergoing undesirable axial movement during the installation of the chromatographic column into the injection module.

[0006] Therefore, according to an embodiment of the present invention, a tool for pre-fixing a chromatographic column to a graphite ferrule includes a tool body and a compression pre-tightening mechanism; the tool body is provided with a positioning part for positioning the graphite ferrule through which the chromatographic column is inserted; the compression pre-tightening mechanism includes a force loading module and a pusher; the force loading module is used to output a push force; the pusher is movably disposed in the tool body and has a receiving hole for the chromatographic column passing through the graphite ferrule to be inserted; the pusher is used to receive the push force and apply an axial pre-tightening force to the graphite ferrule positioned at the positioning part.

[0007] In one embodiment, the force loading module includes a rotary input component and a transmission mechanism, the transmission mechanism being connected between the rotary input component and the pushing component, for converting the rotational motion of the rotary input component into the axial linear motion of the pushing component.

[0008] In one embodiment, the transmission mechanism includes an end-face ratchet transmission pair; the end-face ratchet transmission pair includes a driving ratchet and a driven ratchet, the driving ratchet being used to receive the rotational motion of the rotary input member; the driven ratchet meshing with the driving ratchet.

[0009] In one embodiment, the end-face ratchet drive pair is a one-way meshing drive pair, and is configured such that when the output torque of the force loading module exceeds a preset value, the driving ratchet and the driven ratchet slip circumferentially.

[0010] In one embodiment, the force loading module further includes an elastic torque limiting member for applying axial preload to the end face ratchet drive pair.

[0011] In one embodiment, the rotary input component is circumferentially limited and axially slidable with the active ratchet; the elastic torque limiting component is a compression spring, which is sleeved on the outside of the rotary input component, with one end abutting against the limiting step of the rotary input component and the other end abutting against the end face of the active ratchet.

[0012] In one embodiment, the elastic torque limiting member limits the maximum output torque of the driven ratchet to 0.4 N·m, and further limits the maximum axial force generated by the pushing member to 500 N.

[0013] In one embodiment, the inner hole of the driven ratchet is provided with an internal thread, the pusher is inserted into the inner hole, and its outer wall is provided with an external thread that meshes with the internal thread. The two cooperate to form a helical transmission mechanism. The pusher is circumferentially limited to the tool body, and its rotational degree of freedom is constrained by the tool body. The movement degree of freedom of the driven ratchet is constrained by the tool body.

[0014] In one embodiment, the rotary input component is rotatably mounted in a first mating hole of the tool body and supported by the first mating hole; the driven ratchet is rotatably mounted in a second mating hole of the tool body and supported by the second mating hole.

[0015] In one embodiment, a bushing is built into the first mating hole, and the rotary input component passes through the bushing; the driven ratchet is mounted in the second mating hole via a bearing.

[0016] In one embodiment, the end of the pusher away from the graphite sleeve is provided with a non-circular shaft segment, and the tool body is provided with a non-circular limiting groove adapted to the non-circular shaft segment. The non-circular shaft segment is inserted into the non-circular limiting groove to form a circumferential limiting fit.

[0017] In one embodiment, the positioning part includes an end cap detachably connected to the tool body, the end cap having a through hole for the chromatographic column to pass through, and the end cap being detachably connected to the tool body and cooperating to form a positioning cavity for accommodating a graphite ferrule.

[0018] In one embodiment, the end cap is threaded to the tool body.

[0019] In one embodiment, the receiving hole extends axially along the pusher, with one end penetrating through the end of the pusher and the other end penetrating laterally from the pusher.

[0020] In one embodiment, the tool body has an observation window communicating with the receiving hole, the observation window being used to observe the end of the chromatographic column entering the receiving hole.

[0021] In one embodiment, the tool body integrates a cutting mechanism with the cutting end of the cutting mechanism facing the receiving hole for removing excess segments of the chromatographic column.

[0022] In one embodiment, the cutting mechanism includes a button with a cutting blade, a return spring, and a fixing plate. The cutting blade is fixed to the end of the button, and the return spring is disposed between the button and the fixing plate.

[0023] According to an embodiment of this utility model, under the action of the compression pre-tightening mechanism, the pushing member applies an axial pre-tightening force to the graphite ferrule. Under the action of the pre-tightening force, the graphite ferrule undergoes plastic deformation, thus clamping the chromatographic column like a tight band, achieving pre-fixation of the chromatographic column and the graphite ferrule. During the installation of the fixed chromatographic column and graphite ferrule into the injection module, the relative axial positions of the chromatographic column and graphite ferrule are stably constrained, preventing any relative movement between them and avoiding the problem of axial movement of the chromatographic column relative to the graphite ferrule during the pre-tightening process. Attached Figure Description

[0024] To further clarify the tool according to the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments, in which: Figure 1 This is a schematic diagram showing one end of the chromatographic column connected to the injection module; Figure 2 It is a cross-sectional view of the tool; Figure 3 It is a 3D diagram of the tool; Figure 4 The image shows a view of the chromatographic column being pre-fixed to a graphite ferrule using a tool. Figure 5 It is a 3D diagram of the cutting mechanism of the tool.

[0025] The above figures are for illustrative purposes only and are not drawn to scale.

[0026] The reference numerals in the figures are listed in the figures and embodiments: 1. Tool body 101 Positioning unit 102 First mating hole; 103 Second mating hole 104 Non-circular limiting groove; 105 Observation window 2 Compression preload mechanism 21 Force loading module 22 Pushing component 221 Receiving hole 223 Non-circular shaft segment 3. Rotary input component 301: Limiting step 4. Transmission Mechanism 41. Drive Face Ratchet 42 Driven ratchet 5. Elastic torque limiting component 6. Bushing 7. Bearing 8. End cap 801 positioning cavity 9. Cutting Mechanism 901 Cutting Blade 902 Button; 903 Reset Spring 904 Fixing Plate 10 Graphite Fitting 11 Chromatographic column Detailed Implementation

[0027] The tool of this utility model will now be described by way of example. The terms “outer” or “inner” used herein to indicate orientation or direction, and the terms “first”, “second”, etc., used to indicate sequence, are merely to enable those skilled in the art to better understand the concept of this utility model as shown in the preferred embodiment, and are not intended to limit the utility model. Unless otherwise stated, all sequences, orientations, or directions are used only to distinguish one element / component / structure from another, and unless otherwise stated, do not indicate any particular order, sequence of operations, direction, or orientation.

[0028] Gas chromatographs are core detection devices in laboratories for the separation, qualitative, and quantitative analysis of multi-component samples. Their basic structure consists of a separation section and an analysis section. The separation section includes a carrier gas supply unit, a flow meter, an injection module, a column oven, and a chromatographic column. The analysis section includes a detector and a data processing and recording system. The tool provided in this embodiment is applied to the connection and installation of the chromatographic column and the injection module, specifically for the pre-fixation preparation process of the column and graphite ferrule before formal column installation.

[0029] The standard workflow of a gas chromatograph includes: an autosampler draws a preset volume of sample using a syringe; the syringe passes through the injection port and injects the sample into a heated injection ferrule; the liquid sample rapidly vaporizes into gas at high temperature; carrier gas flows into the injection port in a controlled manner, carrying the vaporized sample into the chromatographic column; the chromatographic column is temperature-controlled to allow different components in the sample to have different retention times due to differences in volatility, polarity, and interaction with the stationary phase, thus achieving precise separation of multiple components; the separated components sequentially enter the detector, which converts the component concentration signal into an electrical signal, and finally, after processing by the data processing system, a chromatogram containing parameters such as peak area and retention time is generated, completing the sample detection.

[0030] As a key component for separating sample components, the performance of the chromatographic column in connection with the injection module directly determines the sealing performance of the injection system, the separation effect of the chromatographic column, and the stability and repeatability of the final detection results. Figure 1 A schematic diagram of the chromatographic column 11 installed in the injection module 12 is shown.

[0031] According to the embodiments described later, when installing the chromatographic column 11, the chromatographic column 11 is first inserted into the graphite sleeve 10 and the locking nut 13. Pre-tightening deforms the graphite sleeve 10 to grip the chromatographic column 11, completing the pre-fixation of the chromatographic column 11 and the graphite sleeve 10. Then, the pre-fixed chromatographic column 11 is installed into the corresponding interface of the injection module 12 via the locking nut 13. The tool provided in this embodiment realizes the above-mentioned pre-fixation process of the chromatographic column 11 and the graphite sleeve 10, which can solve the problem of the chromatographic column 11 easily moving axially relative to the graphite sleeve 10 during the existing installation process. Furthermore, in optional embodiments, it further solves the problems of uncontrollable pre-tightening force and inconsistent extension lengths of the chromatographic column 11 relative to the graphite sleeve 10.

[0032] like Figure 2 and Figure 3 As shown, one embodiment of the present invention provides a tool for pre-fixing a chromatographic column to a graphite sleeve, including a tool body 1 and a compression pre-tightening mechanism 2.

[0033] The tool body 1 is a shell structure, with a positioning part 101 at one end, and referenced... Figure 4 The positioning part 101 is used to position the graphite ferrule 10 through which the chromatographic column 11 is inserted, and to provide axial support for the graphite ferrule 10 to prevent axial movement of the graphite ferrule 10 during the pre-tightening process.

[0034] The compression pre-tightening mechanism 2 is integrated inside the tool body 1. The compression pre-tightening mechanism 2 includes a force loading module 21 and a pusher 22. The force loading module 21 is used to output axial thrust. The pusher 22 is linearly movable along the axial direction and is disposed in the internal cavity of the tool body 1. The pusher 22 has a receiving hole 221 inside, which is used to allow the chromatographic column 11 passing through the central hole of the graphite sleeve 10 to pass through, providing a receiving and guiding space for the chromatographic column 11. The end of the pusher 22 facing the positioning part 101 is the pusher end. The pusher 22 is used to receive the thrust output by the force loading module 21 and apply axial pre-tightening force to the graphite sleeve 10 positioned at the positioning part 101.

[0035] The pusher 22 applies an axial preload to the graphite sleeve 10. Under the preload, the graphite sleeve 10 undergoes plastic deformation, thus clamping the chromatographic column 11 like a clamp, achieving pre-fixation of the chromatographic column 11 and the graphite sleeve 10. During the installation of the fixed chromatographic column 11 and graphite sleeve 10 into the injection module 12, their relative axial positions are stably constrained, preventing any relative movement between them. This avoids the problem of axial movement of the chromatographic column 11 relative to the graphite sleeve 10 during the preload process, ensuring the stability and consistency of the extended length of the chromatographic column 11.

[0036] like Figure 4 As shown, in one embodiment, the force loading module 21 includes a rotary input component 3 and a transmission mechanism 4. The transmission mechanism 4 is connected between the rotary input component 3 and the pusher component 22, and is used to convert the rotational motion input by the rotary input component 3 into the axial linear motion of the pusher component 22. In an optional embodiment, the rotary input component 3 includes a knob structure, the operating end of which is exposed outside the tool body 1, facilitating manual input of rotational force by the operator to provide power input to the transmission mechanism.

[0037] By using a rotary input component in conjunction with a transmission mechanism, manual rotary operation can be smoothly converted into axial linear feed of the pusher component. The operation method is compatible with the conventional manual operation habits in the laboratory. The force loading module 21 occupies little space, making it easy to package and transport. In addition, the transmission process is controllable, enabling continuous and smooth application of preload.

[0038] The transmission mechanism 4 includes an end-face ratchet transmission pair, which includes a driving ratchet 41 and a driven ratchet 42. The driving ratchet 41 is connected to the rotary input component 3 for receiving the rotational motion of the rotary input component 3. The end face of the driven ratchet 42 is provided with meshing teeth that are fully adapted to the ratchet teeth of the driving ratchet 41. The driven ratchet 42 and the driving ratchet 41 mesh with each other to realize the transmission of rotational power.

[0039] Rotational power is transmitted through an end-face ratchet drive pair. The transmission structure is compact and the meshing is reliable, which can be adapted to the internal layout requirements of miniaturized handheld tools. At the same time, the ratchet structure can achieve stable unidirectional transmission and avoid the problem of reverse loosening during pre-tightening.

[0040] In one embodiment, the end-face ratchet drive pair is configured as a one-way meshing drive pair, which can only transmit rotational torque in the preload feed direction. When rotating in the opposite direction, the ratchet slips and cannot transmit torque. At the same time, by designing the ratchet shape of the moving ratchet 41 and the driven ratchet 42, the end-face ratchet drive pair 4 is configured such that when the output torque of the force loading module 21 exceeds the preset value, the driving ratchet 41 and the driven ratchet 42 slip circumferentially, interrupting the transmission of rotational torque.

[0041] The unidirectional meshing design prevents reverse loosening during pre-tightening, ensuring the stability of the pre-tightening operation. The ultra-torque slippage design controls the upper limit of the pre-tightening torque, preventing problems such as graphite ferrule breakage and column damage caused by over-tightening, while ensuring consistent pre-tightening results for different operators.

[0042] In one embodiment, the force loading module 21 further includes an elastic torque limiting member 5, which is used to apply axial preload to the end face ratchet transmission pair 4. The slippage torque threshold of the end face ratchet transmission pair is positively correlated with the axial preload. The preset slippage torque can be set by adjusting the axial preload.

[0043] In one embodiment, the rotary input component 3 and the driving ratchet 41 are circumferentially limited and axially slidable. The circumferential limiting fit ensures the stable transmission of rotational torque from the rotary input component 3 to the driving ratchet 41, while the axially slidable fit accommodates the preload adjustment and axial displacement requirements of the elastic torque limiting component 5. One embodiment of the elastic torque limiting component 5 is a compression spring, which is coaxially sleeved on the outside of the rotary input component 3. One end of the compression spring abuts against the limiting step 301 of the rotary input component 3, and the other end abuts against the end face of the driving ratchet 41 facing away from the ratchet teeth, providing continuous and stable axial preload to the driving ratchet 41.

[0044] In one application scenario, after calibration of the stiffness and pre-compression of the compression spring, the elastic torque limiter 5 limits the maximum output torque of the driven ratchet 42 to 0.4 Newtons. The maximum axial force generated by the pusher 22 is further limited to 500 Newtons. This parameter is adapted to the pre-tightening requirements of the graphite ferrule 10 for gas chromatographs. It can ensure that the graphite ferrule 10 stably grips the chromatographic column 11 after being compressed and deformed, while completely avoiding the problems of the graphite ferrule 10 breaking and the chromatographic column 11 wall being damaged due to excessive pre-tightening force.

[0045] The elastic torque limiting component provides stable axial preload to the end face ratchet drive pair, enabling the calibration and setting of the slippage torque threshold. The structure is simple and calibration is convenient. By matching the parameters of the gas chromatography scenario, it can be directly adapted to the column installation requirements of conventional laboratories without the need for operators to make adjustments themselves, thus lowering the operation threshold and ensuring the consistency of the pre-tightening effect.

[0046] The driven ratchet 42 has an internal thread 421 in its central inner hole. The pusher 22 passes through this inner hole, and the outer wall of the pusher 22 has an external thread 222 that meshes with the internal thread 421. The two work together to form a helical transmission mechanism. The pusher 22 is circumferentially limited to the tool body 1, and its rotational freedom is completely constrained by the tool body 1, allowing it to move only in a straight line along the axial direction. The axial movement freedom of the driven ratchet 42 is constrained by the tool body 1, allowing it to rotate only around its own axis and preventing axial movement, thus ensuring that it always maintains a stable engagement with the driving ratchet 41.

[0047] The helical transmission mechanism can precisely convert the rotational motion of the driven ratchet into the axial linear feed of the pusher, resulting in high transmission accuracy and smooth feed. It can achieve micron-level preload stroke control. The axial limit of the driven ratchet and the circumferential limit of the pusher ensure stable and reliable transmission.

[0048] like Figure 2 As shown, the tool body 1 has a first mating hole 102 and a second mating hole 103 coaxially arranged. The rotary input component 3 is rotatably installed in the first mating hole 102, which provides radial support. The driven ratchet 42 is rotatably installed in the second mating hole 103, which provides radial support.

[0049] In one embodiment, a bushing 6 is housed within the first mating hole 102. The rotary input component 3 passes through the inner hole of the bushing 6. The bushing 6 can be made of a material chosen to reduce frictional resistance and improve operational smoothness, or a material with lower hardness can be chosen to reduce wear on the rotary input component 3 and extend tool life. The driven ratchet 42 is mounted in the second mating hole 103 via a bearing 7. The outer ring of the bearing 7 is interference-fitted with the second mating hole 103, and the inner ring of the bearing 7 is interference-fitted with the outer wall of the driven ratchet 42, further reducing the rotational frictional resistance of the driven ratchet 42, ensuring transmission efficiency, and simultaneously constraining the radial runout of the driven ratchet 42, ensuring reliable engagement with the driving ratchet 41. Optionally, a limit nut 106 is connected to the end face of the driven ratchet 42 to further constrain the axial movement freedom of the driven ratchet 42.

[0050] The split coaxial mating hole structure ensures the coaxiality of the rotary input component and the driven ratchet, avoiding problems such as jamming and ratchet wear during transmission; the bushing and bearing configuration improves the flexibility of the structural design.

[0051] The pusher 22 has a non-circular shaft segment 223 at its end away from the graphite sleeve 10. A corresponding non-circular limiting groove 104, perfectly matching the cross-sectional shape of the non-circular shaft segment 223, is provided on the tool body 1. The non-circular shaft segment 223 engages in the non-circular limiting groove 104, forming a circumferential limiting fit. The non-circular shaft segment 223 can slide freely along the axial direction of the non-circular limiting groove 104, while its rotational freedom is fully constrained. In an optional embodiment, the non-circular shaft segment 223 is a square shaft structure, and the non-circular limiting groove 104 is a square groove structure, which facilitates processing, ensures reliable limiting, and eliminates the circumferential movement problem caused by fit clearance.

[0052] By cooperating with the non-circular shaft section and the limiting groove, reliable circumferential limiting of the jacking part is achieved, ensuring that the screw transmission mechanism can stably convert rotational motion into axial linear motion, avoiding transmission failure caused by the synchronous rotation of the jacking part with the follower ratchet. The structure is simple, the limiting is reliable, and the processing cost is low.

[0053] like Figure 2 and Figure 4As shown, the positioning part 101 includes an end cap 8 detachably connected to the end of the tool body 1. The end cap 8 has a through hole at its center for the chromatographic column 11 to pass through. The inner diameter of the through hole is larger than the outer diameter of the chromatographic column 11 but smaller than the outer diameter of the graphite ferrule 10, ensuring that the chromatographic column 11 can pass freely while axially limiting the graphite ferrule 10. The end cap 8 is detachably connected to the tool body 1 and cooperates to form a positioning cavity 801 for accommodating the graphite ferrule 10. The inner diameter of the positioning cavity 801 is adapted to the outer diameter of the graphite ferrule 10, enabling radial and axial positioning of the graphite ferrule 10.

[0054] In an optional embodiment, the inner wall of the end cap 8 is provided with an internal thread, and the end of the tool body 1 is provided with a matching external thread. The end cap 8 is threadedly connected to the tool body 1, which is convenient to install and remove and reliable in positioning, and can quickly complete the installation, removal and positioning of the graphite ferrule 10.

[0055] The positioning cavity formed by the detachable end cap enables quick installation and removal and precise positioning of the graphite ferrule, ensuring the axial position of the graphite ferrule is fixed during the pre-tightening process, further preventing the graphite ferrule from shifting during the pre-tightening process and improving the consistency of the pre-tightening effect; the threaded connection makes installation and removal convenient and is suitable for the high-frequency use needs of the laboratory.

[0056] like Figure 4 As shown, the receiving hole 221 extends axially along the pusher 22, with its right end penetrating at the end of the pusher 22 away from the graphite sleeve 10, and its left end penetrating laterally from the side wall of the pusher 22, forming a receiving channel with double openings in the axial and lateral directions. After the chromatographic column 11 passes through the graphite sleeve 10, it can enter the receiving hole 221 axially and exit from the lateral opening, thus exposing the end of the chromatographic column 11.

[0057] The tool body 1 has an observation window 105 that communicates with the receiving hole 221. The observation window 105 corresponds to the position of the lateral through opening of the receiving hole 221 and is used to observe the end position of the chromatographic column 11 entering the receiving hole 221, so as to realize the visual confirmation of the insertion length of the chromatographic column 11.

[0058] The end of the chromatographic column can protrude from the lateral opening through the receiving hole 221, allowing any excess length of the column to freely enter the receiving hole 221. The insertion position of the column can be quickly confirmed using the observation window 105.

[0059] The tool body 1 integrates a cutting mechanism 9, with the cutting end of the cutting mechanism 9 facing the receiving hole 221, used to remove excess segments of the chromatographic column 11. Before the pre-tightening operation, the chromatographic column 11 has been positioned, and the pusher 22 only advances forward along the axial direction to apply the pre-tightening force. During the pre-tightening process, the graphite sleeve 10 gradually clamps and fixes the chromatographic column 11, and the length between the cutting position and the graphite sleeve remains fixed, thus realizing the setting of the chromatographic column extension length.

[0060] In one embodiment, the cutting mechanism 9 includes a button 902 with a cutting blade 901, a return spring 903, and a fixing plate 904. The fixing plate 904 is fixed inside the tool body 1, providing stable support for the cutting mechanism 9. The cutting blade 901 is fixed to the end of the button 902, with its cutting edge facing the communication position between the receiving hole 221 and the observation window 105, ensuring the accuracy of the cutting position. The return spring 903 is located between the button 902 and the fixing plate 904, providing a return spring force for the button 902.

[0061] During operation, pressing button 902 will move the cutting blade 901 toward the chromatographic column 11, completing the flat cutting of the excess segments of the chromatographic column 11. After releasing button 902, the reset spring 903 pushes button 902 and the cutting blade 901 to automatically reset, without affecting the installation and removal of the chromatographic column 11.

[0062] By integrating the cutting mechanism into the tool body, the excess length of the chromatographic column can be cut in situ directly after pre-tightening, without the need to change tools or reposition, reducing operational steps and human error, and improving the efficiency of column installation and length setting; the button-type cutting structure makes operation simple and the cut is clean, avoiding damage to the column end that could affect the gas chromatography analysis results.

[0063] While the above description, in conjunction with embodiments, illustrates the tool for pre-fixing a chromatographic column to a graphite ferrule, it should be understood by those skilled in the art that the examples are merely illustrative and not intended to limit the scope of the invention. Therefore, various modifications and variations can be made to the invention within the spirit and scope of the claims, and all such modifications and variations will fall within the scope claimed by the claims.

Claims

1. A tool for pre-fixing a chromatographic column to a graphite ferrule, characterized in that, The tool body and the compression pre-tightening mechanism are included; The tool body is provided with a positioning part for positioning a graphite sleeve through which a chromatographic column is inserted; The compression pre-tightening mechanism includes a force loading module and a pushing piece; The force loading module is used for outputting a pushing force; The pushing piece is movably arranged in the tool body and has a receiving hole for the chromatographic column inserted through the graphite sleeve; The pushing piece is used for receiving the pushing force and applying an axial pre-tightening force to the graphite sleeve positioned in the positioning part.

2. The tool of claim 1, wherein, The force loading module includes a rotary input and a transmission mechanism connected between the rotary input and the pushing piece, which is used for converting the rotary motion of the rotary input into the axial linear motion of the pushing piece.

3. The tool of claim 2, wherein, The transmission mechanism includes an end face ratchet transmission pair; The end face ratchet transmission pair includes a driving face ratchet and a driven face ratchet, the driving face ratchet is used for receiving the rotary motion of the rotary input; The driven face ratchet is engaged with the driving face ratchet.

4. The tool of claim 3, wherein, The end face ratchet transmission pair is a one-way engagement transmission pair, and is configured to cause circumferential slip between the driving face ratchet and the driven face ratchet when the output torque of the force loading module exceeds a preset value.

5. The tool of claim 4, wherein, The force loading module further includes an elastic torque limiting piece for applying an axial pre-pressing force to the end face ratchet transmission pair.

6. The tool of claim 5, wherein, The rotary input is in circumferential limiting fit and axial slidable fit with the driving face ratchet; The elastic torque limiting piece is a compression spring, The compression spring is sleeved on the outside of the rotary input, one end of the compression spring abuts against a limiting step of the rotary input, and the other end abuts against an end face of the driving face ratchet.

7. The tool of claim 5, wherein, The maximum output torque of the driven face ratchet is limited to 0.4 Nm, and the maximum axial force generated by the pushing piece is limited to 500 N.

8. The tool of claim 3, wherein, The inner hole of the driven face ratchet is provided with an internal thread, the pushing piece is arranged in the inner hole, and the outer wall of the pushing piece is provided with an external thread engaged with the internal thread, and the two form a screw transmission mechanism; the pushing piece is in circumferential limiting fit with the tool body, and the rotational degree of freedom of the pushing piece is constrained by the tool body; the movement degree of freedom of the driven face ratchet is constrained by the tool body.

9. A tool according to claim 3 or 4, characterised in that The rotary input is rotatably installed in a first fitting hole of the tool body and supported by the first fitting hole; The driven face ratchet is rotatably installed in a second fitting hole of the tool body and supported by the second fitting hole.

10. The tool of claim 9, wherein, The first fitting hole is internally provided with a bushing, and the rotary input is arranged in the bushing; The driven face ratchet is installed in the second fitting hole through a bearing.

11. The tool of claim 4, wherein, The end of the pushing piece away from the graphite sleeve is provided with a non-circular shaft segment, the tool body is provided with a non-circular limiting groove matched with the non-circular shaft segment, the non-circular shaft segment is clamped into the non-circular limiting groove to form a circumferential limiting fit.

12. The tool of claim 1, wherein, The positioning part includes an end cover detachably connected to the tool body, the end cover is provided with a through hole through which the chromatographic column passes, and the end cover is detachably connected to the tool body and cooperates with the tool body to form a positioning cavity for accommodating the graphite sleeve.

13. The tool of claim 12, wherein, The end cover is threadedly connected to the tool body.

14. The tool of claim 1, wherein, The accommodating hole extends along the axial direction of the pusher, and one end penetrates the end of the pusher, and the other end penetrates the side of the pusher.

15. The tool of claim 1 or 14, wherein, The tool body is provided with an observation window in communication with the accommodating hole, and the observation window is used for observing the end of the chromatographic column entering the accommodating hole.

16. The tool of claim 1, wherein, The tool body is integrated with a cutting mechanism, and a cutting end of the cutting mechanism is directed to the accommodating hole, and is used for cutting off the excess segment of the chromatographic column.

17. The tool of claim 16, wherein, The cutting mechanism comprises a button with a cutting blade, a reset spring and a fixed plate, the cutting blade is fixed to the end of the button, and the reset spring is arranged between the button and the fixed plate.

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