Line, line connection and liquid chromatography system with a sealing head

Abstract

The application provides a pipeline with a sealing head, a pipeline connector and a liquid chromatography system, and solves the problem of low service life of the sealing element at the connection between the pipeline and the target assembly in the prior art. The pipeline with the sealing head comprises: a pipeline body comprising a connecting end, the connecting end comprising first and second sections arranged adjacently, the first section comprising an end face perpendicular to an axis; a sealing element comprising coaxially arranged first and second annular portions; the second annular portion comprises a first surface facing the first annular portion, and an axial projection of the first annular portion falls within the first surface; the first surface comprises a first region surrounded by the projection and a second region surrounding the projection; the first annular portion is sleeved on an outer wall of the first section, and the end face abuts against the first region; and a sleeve is sleeved on an outer wall of the second section and the first annular portion, and one side end face of the sleeve abuts against the second region.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fluid connection system components, in particular to a pipeline with a sealing head, a pipeline connector and a liquid chromatography system. BACKGROUND

[0002] Liquid chromatography is a technique for separating constituent elements in a given sample, which is usually carried by a liquid solvent flowing through a liquid chromatography system, separated by a solid phase to achieve the purpose of element detection. The liquid chromatography system usually includes filter, check valve, guard column, chromatographic column and other components, and pipelines for connecting these components in series. In order to achieve good separation efficiency, most of the liquid in the liquid chromatography is in a high pressure state, so the sealing requirements of the pipeline and the connection position are higher.

[0003] In the traditional connection system, in order to achieve good sealing performance under high pressure, the metal sealing piece is pressed into the socket extending inwardly and tapering to achieve sealing by means of fastening screw between the connecting pipeline and the target component socket unit. At this time, due to the gap between the pipeline and the socket unit, an invalid volume is generated. At the same time, due to the different specifications of the socket units of different target components, the same pipeline connector may not be able to connect with the target component, or the invalid volume is increased.

[0004] The pipeline design in the prior art generally focuses on sealing performance and dead volume. For example, a Chinese invention patent with publication number CN102239408A discloses a plug unit and a socket unit for connecting capillary tubes. The plug unit includes a capillary tube with a bearing area 11 arranged at the end of the capillary tube, i.e., the end of the capillary tube is provided with a radial protrusion forming the bearing area 11, which is used to abut against a seal 40 sleeved on the outer wall of the capillary tube. In use, the plug unit is inserted into the socket unit, the seal 40 is radially deformed, the side wall of the seal 40 forms a radial seal, and the end face of the seal 40 forms an axial seal, so that the connection of the pipeline has high sealing performance and avoids liquid leakage. For another example, a US invention patent with publication number US20100005855A1 discloses a connector for connecting a gas chromatography capillary column to a chromatography device. The connector includes a nut 18 and a main body 24 used in cooperation, and the main body 24 is similar to a screw. In use, first, a ferrule 20 is sleeved on the end of the capillary tube, and then the end of the capillary tube is inserted into the through hole inside the main body 24, the nut 18 is rotated to threadedly connect the nut 18 and the main body 24, and the ferrule 20 (equivalent to the seal) is pressed to achieve sealing during the rotation of the nut 18. The main body 24 includes a fixed base 22 and a hub 42 arranged coaxially, and a part of the fixed base 22 is inserted into the hub 42. An axially extending groove 36 is arranged on the side wall of the fixed base 22, a radially movable positioning pin 38 is arranged on the side wall of the hub 42, and one end of the movable positioning pin 38 is inserted into the groove 36. By axially moving the fixed base 22 and then locking by the positioning pin, the position of the capillary tube can be finely adjusted by the fixed base 22, so as to reduce the dead volume.

[0005] It can be seen that the connector in the prior art described above needs to assemble the seal before each use. In this case, after long-term use and repeated assembly and disassembly, the outer wall of the seal will be worn, the side wall will become thinner and thinner, the inner hole of the seal will become larger and larger, the sealing performance will be affected, and even the seal will be broken or dropped, resulting in a relatively low service life of the seal. SUMMARY

[0006] Therefore, the embodiments of the present application are dedicated to providing a pipeline with a sealing head to solve the problem of a relatively low service life of the seal at the connection between the pipeline and the target component in the prior art.

[0007] The first aspect of the present application provides a pipeline with a sealing head, comprising: a pipeline body comprising a connecting end, the connecting end comprising a first section and a second section arranged adjacently, the first section comprising an end face perpendicular to an axis; a sealing member comprising a first annular portion and a second annular portion arranged coaxially; the second annular portion comprising a first surface facing the first annular portion, and an axial projection of the first annular portion falling within the first surface; the first surface comprising a first region surrounded by the axial projection and a second region surrounding the axial projection; the first annular portion being sleeved on an outer wall of the first section, and the end face being in abutment with the first region; and a sleeve being sleeved on an outer wall of the second section and the first annular portion, one side end face of the sleeve being in abutment with the second region.

[0008] In one embodiment, at least part of the sleeve and the first annular portion are in a sliding fit.

[0009] In one embodiment, in a direction gradually away from the second annular portion, an outer diameter of the first annular portion is in a decreasing trend, and an inner diameter of a section of the sleeve sleeved on the outer wall of the first annular portion is in a decreasing trend.

[0010] In one embodiment, in a direction gradually away from the second annular portion, an outer diameter of the first annular portion is in an increasing trend; and an inner wall of a section of the sleeve sleeved on the outer wall of the first annular portion is cylindrical.

[0011] In one embodiment, an inner diameter of the second annular portion is 1.05-1.65 times an inner diameter of the pipeline body.

[0012] In one embodiment, an outer diameter of the second annular portion first increases and then decreases along the axis.

[0013] In one embodiment, the outer diameter of the second annular portion repeats the rule of first increasing and then decreasing along the axis for multiple times.

[0014] In one embodiment, the second annular portion further comprises a second surface arranged opposite to the first surface, and a side surface connecting the first surface and the second surface, and the second surface and the side surface are smoothly connected.

[0015] In one embodiment, the sleeve comprises a first part sleeved on an outer wall of the second section and a second part sleeved on an outer wall of the first annular portion; the first part comprises a first shrinkage portion, and / or the second part comprises a second shrinkage portion.

[0016] The second aspect of the present application provides a pipeline connector, comprising: a screw comprising a first through hole, the first through hole comprising a first section and a second section arranged adjacently; a diameter of the first section of the first through hole being greater than a diameter of the second section of the first through hole; and a first step structure being formed at a boundary between the first section of the first through hole and the second section of the first through hole.

[0017] In one embodiment, the outer wall of the screw comprises a first section and a second section arranged adjacently, the diameter of the first section of the outer wall of the screw is smaller than the diameter of the second section of the outer wall of the screw; the first section of the outer wall of the screw is provided with threads.

[0018] In one embodiment, the plane where the first step structure is located passes through the threads on the first section of the outer wall of the screw.

[0019] In one embodiment, the side wall of the screw is provided with a first opening exposing the first through hole, the first opening penetrates the side wall of the screw in the axial direction; the width of the first opening in the direction perpendicular to the axis of the first through hole is smaller than the diameter of the first section of the first through hole and greater than or equal to the diameter of the second section of the first through hole.

[0020] In one embodiment, further comprising a cap detachably connected with the screw, the cap comprising a second through hole and a protrusion extending in the axial direction of the second through hole; in the assembled state, the second through hole and the first through hole are coaxially arranged, and the protrusion at least partially fills the first opening.

[0021] In one embodiment, the first through hole further comprises a third section located on the side of the second section away from the first section, the radial cross-sectional area of the third section of the first through hole is greater than the radial cross-sectional area of the second section of the first through hole, and the boundary between the third section of the first through hole and the second section of the first through hole forms a second step structure; the outer wall of the cap comprises a first section, and the outer diameter of the first section of the outer wall of the cap and the inner diameter of the third section of the first through hole of the screw are in a snap-fit.

[0022] In one embodiment, the outer wall of the cap further comprises a second section connected with the first section, the second section of the outer wall of the cap is located on the side of the first section of the outer wall of the cap away from the screw, and the radial cross-sectional area of the second section of the outer wall of the cap is greater than the radial cross-sectional area of the second section of the outer wall of the screw.

[0023] In one embodiment, the side wall of the cap is provided with a second opening exposing the second through hole, the second opening penetrates the side wall of the cap in the axial direction of the second through hole; the second opening and the protrusion are arranged alternately in the circumferential direction.

[0024] The third aspect of the present application provides a liquid chromatography system, comprising a pipeline connection part, the pipeline connection part comprising: the pipeline with a sealing head provided by any one of the above embodiments; a target assembly comprising a liquid channel inlet with internal threads; and the pipeline connector provided by any one of the above embodiments. Wherein the screw is sleeved on the outer wall of the pipeline; the other side end surface of the sleeve abuts against the first step structure; the screw and the liquid channel inlet are in threaded connection.

[0025] According to the pipeline with a sealing head, pipeline connector, and liquid chromatography system provided in this application, by implementing the sealing element as a first annular portion and a second annular portion arranged coaxially, the first annular portion seals the side of the connection end, i.e., radial sealing; and the second annular portion seals the end face of the connection end, i.e., axial sealing. This allows the pipeline with the sealing head to utilize both sealing methods. Since pipelines with only end face axial sealing will experience wear on the front surface of the sealing element due to long-term use, and pipelines with only side radial sealing are prone to side wear due to repeated installation and removal, the pipeline with the sealing head provided in this embodiment, by combining the two sealing methods, increases the service life by more than double compared to pipelines with only one sealing method under the same conditions. Attached Figure Description

[0026] Figure 1 This is a partial cross-sectional schematic diagram of a pipeline with a sealing head provided in the first embodiment of this application, in a partially disassembled state.

[0027] Figure 2 for Figure 1 The diagram shows a pipeline with a sealing head in an assembled state.

[0028] Figure 3 This is a partial structural diagram of a pipeline with a sealing head in a disassembled state, as provided in the second embodiment of this application.

[0029] Figure 4 This is a partial structural diagram of a pipeline with a sealing head in a disassembled state, as provided in the third embodiment of this application.

[0030] Figure 5 This is a perspective view of the seal provided in the fourth embodiment of this application.

[0031] Figure 6 This is a perspective view of the seal provided in the fifth embodiment of this application.

[0032] Figure 7 This is a structural schematic diagram of the pipeline connector provided in the sixth embodiment of this application.

[0033] Figure 8 This is a schematic diagram of the cross-sectional structure of a screw provided in the seventh embodiment of this application.

[0034] Figure 9 This is a schematic diagram of the cross-sectional structure of the screw provided in the eighth embodiment of this application.

[0035] Figure 10 This is a schematic diagram of the structure of a cap provided in an embodiment of this application.

[0036] Figure 11Fig. 1 shows a schematic view of a pipeline connection and a pipeline with a sealing head in an assembled state according to an embodiment of the present application. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0038] Figure 1 Fig. 2 shows a schematic view of a pipeline with a sealing head in a partially disassembled state according to the first embodiment of the present application. Figure 2 For Figure 1 Fig. 1 shows a schematic view of a pipeline connection and a pipeline with a sealing head in an assembled state according to an embodiment of the present application. Fig. 2 shows a schematic view of a pipeline with a sealing head in a partially disassembled state according to the first embodiment of the present application. Figure 1 and Figure 2 As shown in Fig. 1, the pipeline 10 with a sealing head includes a pipeline body 11, a sealing member 12 and a sleeve 13.

[0039] The pipeline body 11 is used to transport liquid. The pipeline body 11 is, for example, a capillary tube, and the material of the capillary tube can be a corrosion-resistant and high-strength metal material, such as stainless steel, alloy, etc. The pipeline body 11 can be a round tube or a square tube, etc. The pipeline body 11 includes a connecting end, and the connecting end includes a first section 111 and a second section 112 arranged adjacent to each other, and the first section 111 includes an end surface S perpendicular to an axis.

[0040] The material of the sealing member 12 is corrosion-resistant plastic, such as poly ether ether ketone (PEEK), polytetrafluoroethylene (PTFE), polypropylene, etc. The sealing member 12 comprises a coaxially arranged first annular portion 121 and a second annular portion 122. The axial length of the first annular portion 121 is greater than the axial length of the second annular portion 122. For example, the first annular portion 121 is similar to a sleeve, and the second annular portion 122 is similar to a gasket, and the second annular portion 122 corresponds to a cap arranged at the end of the first annular portion 121. The second annular portion 122 comprises a first surface P facing the first annular portion 121, the orthographic projection of the first annular portion 121 in the axial direction falls within the first surface P, and the first surface P comprises a first region P1 surrounded by the orthographic projection of the first annular portion 121 and a second region P2 surrounding the orthographic projection. The first annular portion 121 is sleeved on the outer wall of the first section 111, and the end surface S is in abutment with the first region P1 to achieve sealed communication between the internal through hole of the pipeline body 11 and the internal through hole of the second annular portion 122. The inner diameter of the second annular portion 122 is slightly larger than the inner diameter of the pipeline body 11. In an embodiment, the inner diameter of the second annular portion 122 is 1.05-1.65 times the inner diameter of the pipeline body 11. For example, the inner diameter of the second annular portion 122 is 1.2 times, 1.3 times, 1.4 times, etc. the inner diameter of the pipeline body 11. The advantage is that subsequent connection of the pipeline 10 and the target assembly is avoided, and the inner diameter of the second annular portion 122 is reduced due to extrusion deformation, causing liquid phase channel blockage. The first annular portion 121 and the first section 111 are over-matched to facilitate assembly and fixation between the pipeline body 11 and the sealing member 12. The shape of the internal through hole of the first annular portion 121 is adapted to the shape of the pipeline body 11. For example, the pipeline body 11 is a circular pipe, and correspondingly, the internal through hole of the first annular portion 121 is cylindrical. The outer wall shape of the first annular portion 121 can be reasonably set according to actual needs, such as cylindrical, conical, etc. The shape of the internal through hole of the second annular portion 122 is adapted to the shape of the internal through hole of the pipeline body 11. For example, the internal through hole of the second annular portion 122 and the internal through hole of the pipeline body 11 are both cylindrical. The material of the sleeve 13 can be corrosion-resistant and high-strength metal material, such as stainless steel, alloy, etc. In an example, the material of the sleeve 13 is the same as the material of the pipeline body 11. The sleeve 13 is sleeved on the outer wall of the second section 112 and the first annular portion 121, and one side end surface of the sleeve 13 is in abutment with the second region P2. That is, the sleeve 13 is divided into two parts, the first part 131 is sleeved on the outer wall of the second section 112, and the second part 132 is sleeved on the outer wall of the first annular portion 121.The cooperation between the first portion 131 and the second section 112 and the second portion 132 and the first annular portion 121 is selected from any one of tight fit, sliding fit and clearance fit, respectively, to facilitate the assembly between the sleeve 13 and the pipeline body 11 and the seal 12. In one embodiment, the inner wall of the first portion 131 is shaped to match the outer wall of the second section 112. For example, the outer wall of the second section 112 is cylindrical, and the inner wall of the first portion 131 is also cylindrical. In one embodiment, the inner wall of the second portion 132 is shaped to match the outer wall of the first annular portion 121. For example, the outer wall of the first annular portion 121 is cylindrical, and the inner wall of the second portion 132 is also cylindrical. The outer wall of the sleeve 13 is cylindrical.

[0041] The sleeve 13 comprises a first shrinkage portion 133 located at the first portion 131. The first shrinkage portion 133 is used to apply pressure to the second section 112 of the pipeline body 11 to fix the sleeve 13 and the pipeline body 11. In one embodiment, the first shrinkage portion 133 is achieved by riveting, i.e. riveting a predetermined area of the sleeve 13 to form a groove to form the first shrinkage portion 133. The riveting method is low in cost and easy to implement in industry. The sleeve 13 further comprises a second shrinkage portion 134 located at the second portion 132. The second shrinkage portion 134 is used to apply pressure to the first annular portion 121 of the seal 12 to fix the sleeve 13 and the seal 12. In one embodiment, the second shrinkage portion 134 is achieved by shrinkage or riveting. In this way, by respectively providing the first shrinkage portion 133 for fixing the pipeline body 11 and the second shrinkage portion 134 for fixing the seal 12 on the sleeve 13, on the one hand, the first shrinkage portion 133 and the second shrinkage portion 134 are respectively located at both ends of the sleeve 13, and the fixing strength is more reliable. On the other hand, compared with providing only one shrinkage portion to fix the seal 12 and the pipeline body 11 at the same time, the two shrinkage portions can share the fixing pressure, avoiding the excessive pressure of a single shrinkage portion causing the pipeline body 11 to deform and / or the sleeve 13 to crack.

[0042] When the pipeline 10 with the sealing head is connected to the target component, by applying an axial force to the sleeve 13, on the one hand, the second annular portion 122 of the seal 12 undergoes axial deformation, compressing the end face S of the pipeline body 11 to form an axial seal; on the other hand, the first annular portion 121 of the seal 12 undergoes radial deformation, compressing the side wall of the pipeline body 11 to form a radial seal. It can be seen that the pipeline 10 with the sealing head provided according to this embodiment, by combining two sealing methods, namely axial sealing and radial sealing, meets the high-pressure sealing requirements. At the same time, since pipelines with only end-face axial sealing will experience wear on the front face of the seal due to long-term use, and pipelines with only side radial sealing are prone to side wear due to repeated installation and removal, the pipeline 10 with the sealing head provided according to this embodiment, by combining the two sealing methods, under the same conditions, has a service life that is more than doubled compared to pipelines with only one sealing method.

[0043] Figure 3 This is a partial structural diagram of a pipeline with a sealing head in a disassembled state, as provided in the second embodiment of this application. Figure 3 The pipe 20 with the sealing head shown is... Figure 1 and Figure 2 The only difference between the pipe 10 with the sealing head shown is the shape of the sleeve 23 and the shape of the first annular portion 221 of the seal 22.

[0044] Specifically, in this embodiment, as Figure 3 As shown, the sleeve 23 is divided into a first portion 231 and a second portion 232 arranged adjacent to each other. The first portion 231 is used to sleeve the pipeline body 11 (not shown in the figure), and the second portion 232 is fitted onto the first annular portion 221 of the seal 22. The outer diameter of the first annular portion 221 decreases in a direction gradually moving away from the second annular portion 222, and the inner diameter of the second portion 232 of the sleeve 23 also decreases. This decreasing trend includes uniform decrease and step-like decrease. In one example, the outer wall of the first annular portion 221 is conical, and the inner wall of the second portion 232 is conical to match the first annular portion 221.

[0045] According to the pipeline 20 with the sealing head provided in the embodiment, in the direction gradually away from the second annular part 222, the outer diameter of the first annular part 221 is arranged to be in a decreasing trend, and the inner diameter of the second part 232 of the sleeve 23 is also in a decreasing trend, which on one hand makes the second part 232 form a gradually open opening towards the sealing member 22, facilitating the positioning and assembly of the first annular part 221; on the other hand, the closer to the second annular part 222, the greater the required sealing strength. Therefore, by arranging the radial thickness of the region of the first annular part 221 close to the second annular part 222 to be greater than the radial thickness of the region away from the second annular part 222, a better sealing effect can be achieved.

[0046] Figure 4 A partial structure schematic diagram of the pipeline with the sealing head provided in the third embodiment of the present application is in a disassembled state. The pipeline with the sealing head 30 shown in Figure 4 is different from the pipeline with the sealing head 30 shown in Figure 3 only in the shape of the sleeve 33 and the shape of the first annular part 321 of the sealing member 32.

[0047] Specifically, in the embodiment, as shown in Figure 4 the sleeve 33 is divided into the first part 331 and the second part 332 arranged adjacent to each other. The first part 331 is used to sleeve the pipeline body 11 (not shown in the figure), and the second part 332 sleeves the first annular part 321 of the sealing member 32. In the direction gradually away from the second annular part 322, the outer diameter of the first annular part 321 is in an increasing trend, for example, the outer wall of the first annular part 321 is tapered towards the second annular part 322; and the inner diameter of the second part 332 of the sleeve 33 is cylindrical.

[0048] In one embodiment, the first annular part 321 and the second part 332 are partially regionally in sliding fit. For example, in the direction gradually close to the second annular part 322, the outer diameter of the first annular part 321 first remains unchanged and then decreases, the region where the outer diameter of the first annular part 321 remains unchanged and the second part 332 are in overfit, and the region where the outer diameter of the first annular part 321 decreases and the second part 332 are in sliding fit. The advantage of this is that the gap of the sliding fit region can be used to form a containing space to accommodate the deformation of the subsequent sealing member 32 due to extrusion deformation. Avoiding that the deformation stress of the sealing member 32 is too large, reducing the reliability.

[0049] Figure 5 A perspective view of the sealing member provided in the fourth embodiment of the present application is shown in Figure 5As shown, the sealing member 43 comprises coaxially arranged first and second annular portions 431 and 432. The outer diameter of the second annular portion 432 increases first and then decreases along the axial direction. This has the advantages that, on the one hand, the sealing effect is ensured, and on the other hand, the annular recess forms a containing space to accommodate the extrusion deformation of the second annular portion 432 in the subsequent sealing connection process, thereby releasing the deformation stress in the sealing member 32 and improving the reliability while improving the axial sealing effect.

[0050] In one embodiment, the second annular portion 432 comprises a first surface P facing the first annular portion 431 and a second surface Q opposite to the first surface P, and a side surface C connecting the first surface P and the second surface Q, and the second surface Q and the side surface C are smoothly connected. For example, a chamfer is arranged at the junction of the second surface Q and the side surface C. This has the advantages that, on the one hand, during the connection of the pipeline 10 with the sealing head and the target assembly, the sealing head of the pipeline is guided to be inserted into the connection site of the target assembly; and on the other hand, the second annular portion 432 is guided to deform in the radial direction.

[0051] Figure 6 A perspective view of a sealing member according to a fifth embodiment of the present application is provided. As shown in Figure 6 the sealing member 53 and Figure 5 the sealing member 43 differ only in the shape of the outer wall of the second annular portion 532. Specifically, in the present embodiment, the outer diameter of the second annular portion 532 increases first and then decreases along the axial direction repeatedly. In this case, the second annular portion 532 is similar to a sugar cane type or an abacus bead string type. This has the advantage that the side sealing capability can be improved.

[0052] The present application also provides a pipeline connector for connecting the pipeline with the sealing head according to any one of the above embodiments and the assembly to be connected. Figure 7 A structural schematic view of a pipeline connector according to a sixth embodiment of the present application is provided. As shown in Figure 7 the pipeline connector comprises a detachable screw 70 and a cap 80. The screw 70 can be used as a pipeline connector alone without the matched cap 80. The structures of the screw 70 and the cap 80 will be described in detail below with reference to the accompanying drawings.

[0053] Figure 8 A cross-sectional structural schematic view of a screw according to a seventh embodiment of the present application is provided. Figure 9 A cross-sectional structural schematic view of a screw according to an eighth embodiment of the present application is provided. Figure 8 and Figure 9 respectively show the cross-sectional structure of the screw in the plane N in Figure 7 First, refer to Figure 7 and Figure 8As shown, the screw 70 comprises a first through hole 700 comprising a first section 71 and a second section 72 arranged adjacently, the first section 71 of the first through hole 700 has a diameter greater than or equal to the diameter of the second section 72 of the first through hole 700, and the first section 71 of the first through hole 700 and the second section 72 of the first through hole 700 form a first step structure 712.

[0054] Specifically, the screw 70 is tubular, and the internal through hole comprises sections with different diameters, i.e., a first section 71 with a larger diameter and a second section 72 with a smaller diameter. The first section 71 and the second section 72 are connected by an annular plane perpendicular to the axial direction, thereby forming a first step structure 712.

[0055] When connecting the target assembly with the sealed head pipeline and the liquid passage inlet with internal threads provided by any of the above embodiments using the screw 70, first, the non-connection end of the pipeline, i.e., the other end opposite to the connection end, is inserted from the right side of the screw 70. Then, the screw 70 is rotated to screw into the liquid passage inlet. As the length of the screw screwed into the liquid passage inlet increases, the other end of the sleeve 13 of the pipeline 10, i.e., the end away from the seal 12, gradually abuts against the first step structure 712, thereby enabling the sealed end of the pipeline 10 and the liquid passage of the target assembly to be connected in a sealed manner, and having a lower dead volume.

[0056] In one embodiment, as shown in Figure 7 and Figure 8 As shown, the outer wall of the screw 70 comprises a first section 76 and a second section 74 arranged adjacently, the first section 76 of the outer wall of the screw 70 has a smaller diameter than the second section 74 of the outer wall of the screw 70. The first section 76 of the outer wall of the screw 70 is provided with threads, and the second section 74 of the outer wall of the screw 70 is provided with knurling. In this case, the second section 74 with a larger diameter can be used as the force receiving part during assembly, and the first section 76 with a smaller diameter can be used as the threaded part, thereby making the assembly more labor-saving. It should be understood that other rough structures, such as an array of protrusions, etc., can also be provided on the second section 74, without being limited to knurling.

[0057] In one embodiment, the plane where the first step structure 712 is located passes through the threads on the first section 76 of the outer wall of the screw 70. Since the first step structure 712 provides a stop for the pipeline 10 during assembly, the first step structure 712 will be subjected to greater stress. By arranging the plane where the first step structure 712 is located to pass through the threads on the screw 70, the first step structure can be located in the threaded matching area of the screw 70 and the liquid passage inlet of the target assembly, thereby using the liquid passage inlet to protect the first step structure, and improving the reliability of the screw 70.

[0058] In one embodiment, in combination with Figure 7 and Figure 8 As shown in FIG. 7, the side wall of the screw 70 is provided with a first opening 75 exposing the first through hole 700. The first opening 75 penetrates the side wall of the screw 70 along the axial direction of the first through hole 700. The width of the first opening 75 in the direction perpendicular to the axis of the first through hole 700 is less than the diameter of the first section 71 of the first through hole 700 and greater than the diameter of the second section 72 of the first through hole 700. In this case, the pipeline 10 can be inserted along the radial direction of the first through hole 700 through the first opening 75, which is more convenient and efficient than inserting the pipeline 10 from the right end of the screw 70.

[0059] The inventors have found that the screw 70 shown in Figure 7 、 Figure 8 and Figure 9 may cause the pipeline 10 to be ejected from the first opening 75 or bent in the first opening 75 during use. To solve this technical problem, the application also provides a cap 80 used in cooperation with the screw 70. As shown in Figure 7 , the cap 80 is detachably connected with the screw 70, and the cap 80 includes a second through hole 800 and a protrusion 81 extending along the axial direction of the second through hole 800. In the assembled state, the second through hole 800 and the first through hole 700 are coaxially arranged, and the protrusion 81 at least partially fills the first opening 75. In this case, the protrusion 81 can limit the pipeline in the first through hole 700. In one embodiment, the protrusion 81 can also be arranged to at least partially fill the first opening 75 while being clamped with the first opening 75. In this case, the protrusion 81 can also function to fix the cap 80 and the screw 70.

[0060] In one embodiment, in combination with Figure 7 and Figure 9 As shown in FIG. 7, the first through hole 700 of the screw 70 further includes a third section 73 located on the side of the second section 72 away from the first section 71. The radial cross-sectional area of the third section 73 of the first through hole 700 is greater than the radial cross-sectional area of the second section 72 of the first through hole 700, and the boundary between the third section 73 of the first through hole 700 and the second section 72 of the first through hole 700 forms a second step structure 723. That is, the second section 72 and the third section 73 are connected by an annular plane perpendicular to the axial directions of the first through hole 700 and the second through hole 800, thereby forming the second step structure 723 at the annular plane.

[0061] The outer wall of the cap 80 includes a first section 82. The outer diameter of the first section 82 of the outer wall of the cap 80 engages with the inner diameter of the third section 73 of the first through hole 700 of the screw 70. One end face of the cap 80 abuts against the second stepped structure 723. For example, the outer wall of the cap 80 includes a first section 82, which is connected to one end face of the cap 80, and this end face abuts against the second stepped structure 723 of the screw 70. A protrusion 81 is located on this end face, filling a portion of the area of ​​the first opening 75. The protrusion 81 includes an arcuate surface facing the second through hole 800, which smoothly connects to the sidewall of the second through hole 800. In other embodiments, the surface of the protrusion 81 facing the second through hole 800 can also be flat. Comparatively, the arcuate surface can match the shape of the outer wall of the pipeline body 11, avoiding the surface of the protrusion 81 facing the second through hole 800 from forming sharp edges that could compress the pipeline body 11, thus improving reliability. The first section 82 of the cap 80 has a regular polygonal cross section in the direction perpendicular to the axis of the second through hole 800. The inner wall of the third section 73 of the first through hole 700 of the screw 70 has a regular polygonal projection in the direction of the axis of the first through hole 700. The first section 82 and the third section 73 are matched in gap.

[0062] According to the embodiment provided, the cap 80 and the screw 70 are engaged and combined with the protrusion 81 of the first opening 75 of the screw 70 to partially fill the gap, thereby achieving the fixation between the cap 80 and the screw 70. The structure is simple and easy to install.

[0063] In one embodiment, such as Figure 7 As shown, the outer wall of the cap 80 also includes a second section 83 connected to the first section 82. The second section 83 of the outer wall of the cap 80 is located on the side of the first section 82 of the outer wall of the cap 80 away from the screw 70, and the radial cross-sectional area of ​​the second section 83 of the outer wall of the cap 80 is larger than the radial cross-sectional area of ​​the second section 74 of the outer wall of the screw 70. In this way, the second section 83 of the cap 80 can be used instead of the second section 74 of the outer wall of the screw 70 as the force-bearing part, thereby providing greater torque and further reducing the external force required for assembly. In this case, since the cap 80 and the screw 70 are detachable, the screw 70 can be used as a pipeline connector alone. Therefore, when the distance between two adjacent pipeline connectors is too close to cause the caps of the two pipeline connectors to be unable to be set side by side, that is, when the caps 80 of the two pipeline connectors interfere with each other, the cap 80 can be removed after the tightening operation is completed using the cap 80, so that the screw 70 can be used as a pipeline connector alone to accommodate the spacing between adjacent pipeline connectors. It is evident that the pipeline connector provided according to this embodiment has a wider range of applications.

[0064] In one embodiment, the second section 83 of the outer wall of the cap 80 is a rough surface, such as knurling, prismatic pattern, equidistantly arranged strip-shaped protrusions, etc. on the second section 83. In another embodiment, the second section 83 comprises two parallel arranged planes.

[0065] In one embodiment, as shown in Figure 7 , the sidewall of the cap 80 is provided with a second opening 84 exposing the second through hole 800, the second opening 84 penetrating the sidewall of the cap 80 along the axial direction of the second through hole 800, the second opening 84 being used for radially inserting the pipeline from the second through hole 800, facilitating assembly and disassembly. In one example, the width of the second opening 84 in the direction perpendicular to the axis of the second through hole 800 is equal to the width of the first opening 75 in the direction perpendicular to the axis of the first through hole 700. The second opening 84 and the protrusion 81 are arranged in a circumferential staggered manner.

[0066] Figure 10 The structural schematic diagram of the cap provided in one embodiment of the present application is shown in Figure 10 . As shown in Figure 7 , the cap 90 and Figure 7 the cap 80 are different in that, in the present embodiment, the protrusion 81 of the cap 80 is implemented as a separate component rather than a part of the cap 80. Specifically, in combination with Figure 10 and Figure 11 , the cap 90 comprises a base 91 and a limiting member 92 which are detachably connected. The outer wall of the base 91 comprises a first section 911 and a second section 912 which are arranged adjacent in the axial direction, the radial cross-sectional area of the first section 911 being greater than that of the second section 912. In one embodiment, the radial cross-section of the first section 911 is a regular polygon, and the radial cross-section of the second section 912 is a circle. The limiting member 92 comprises a collar 921, a connecting portion 922 and a protrusion 923. The collar 921 can be a closed ring or a ring with an opening. The collar 921 comprises a surface perpendicular to the axis, which is connected to one end of the connecting portion 922, and the other end of the connecting portion 922 is connected to the protrusion 923. The back region of the collar 921 can be divided into a central region and an edge region surrounding the central region, the central region being used for passing through the pipeline body 11. The orthogonal projection of the protrusion 923 in the axial direction of the collar 921 falls within the edge region. In the assembled state, the collar 921 is sleeved on the outer wall of the first section 911 of the base 91, and the protrusion 923 at least partially fills the first opening 75. Figure 11 Figure 2 and 7 ​As shown, in the assembled state, the cap 80 and the screw 70 are sequentially sleeved on the outer wall of the pipeline 10 in the direction gradually approaching the sealing head. The end surface of the sleeve 13 of the pipeline 10 away from the sealing element 12 abuts against the first stepped structure 712 of the screw 70. The protruding part 81 of the cap 80 fills part of the area of the second section 74 of the corresponding outer wall of the first opening 75 of the screw 70, and the first section 82 of the outer wall of the cap 80 and the third section 73 of the inner wall of the screw 70 are in clamping fit.

[0067] The application also provides a liquid chromatography system. The liquid chromatography system comprises a pipeline connection part, the pipeline connection part comprising: the pipeline with a sealing head provided by any one of the above embodiments; a target assembly comprising a liquid channel inlet having an internal thread; and the pipeline connection piece provided by any one of the above embodiments. The target assembly may, for example, be a chromatographic column, a two-way valve, a three-way valve, a sample injection valve, a liquid pump, a detection cell, etc. When the pipeline connection piece only comprises the screw 70, the screw 70 is sleeved on the outer wall of the pipeline, the other side end surface of the sleeve abuts against the first stepped structure 712 in the screw 70, and the screw 70 and the liquid channel inlet are in threaded fit.

[0068] When the pipeline connection piece further comprises the cap 80, the cap 80 is located on the side of the screw 70 away from the sealing head and is sleeved on the outer wall of the pipeline. The protruding part 81 of the cap 80 at least partially fills the first opening 75 on the outer wall of the screw 70.

[0069] It should be noted that the specific structure of the pipeline with a sealing head, the cap 80 and the screw 70 can be referred to the corresponding embodiments described above, and will not be repeated here.

[0070] It should be understood that the adjectives "first", "second", "third" and the like used in the embodiments of the application are only used for clearer description of the technical solutions, and cannot be used to limit the protection scope of the application.

[0071] The above description has been given for the purpose of illustration and description. Furthermore, this description is not intended to limit the embodiments of the application to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain modifications, alterations, changes, additions and sub-combinations thereof.

Claims

1. A pipe coupling, characterized in that The screw comprises a first through hole, the first through hole comprises a first section and a second section arranged adjacently, the diameter of the first section of the first through hole is greater than the diameter of the second section of the first through hole, a first step structure is formed at the boundary between the first section of the first through hole and the second section of the first through hole, a first opening exposing the first through hole is arranged on the sidewall of the screw, the first opening penetrates the sidewall of the screw along the axial direction, the width of the first opening in the direction perpendicular to the axis of the first through hole is less than the diameter of the first section of the first through hole and greater than or equal to the diameter of the second section of the first through hole, and and a cap detachably connected with the screw, the cap comprises a second through hole and a protrusion extending along the axial direction of the second through hole; in the assembled state, the second through hole and the first through hole are coaxially arranged, and the protrusion at least partially fills the first opening; the outer wall of the screw comprises a first section and a second section arranged adjacently, the diameter of the first section of the outer wall of the screw is less than the diameter of the second section of the outer wall of the screw, and a thread is arranged on the first section of the outer wall of the screw.

2. The pipe connection of claim 1, wherein, The plane where the first step structure is located passes through the thread on the first section of the outer wall of the screw.

3. The pipe coupling according to claim 1, wherein, The first through hole further comprises a third section located on the side of the second section away from the first section, the radial cross-sectional area of the third section of the first through hole is greater than the radial cross-sectional area of the second section of the first through hole, and a second step structure is formed at the boundary between the third section of the first through hole and the second section of the first through hole. The outer wall of the cap comprises a first section, the outer diameter of the first section of the outer wall of the cap and the inner diameter of the third section of the first through hole of the screw are in a clamping fit.

4. The pipe connection of claim 3, wherein, The outer wall of the cap further comprises a second section connected with the first section, the second section of the outer wall of the cap is located on the side of the first section of the outer wall of the cap away from the screw, and the radial cross-sectional area of the second section of the outer wall of the cap is greater than the radial cross-sectional area of the second section of the outer wall of the screw.

5. The pipe connection of claim 4, wherein, A second opening exposing the second through hole is arranged on the sidewall of the cap, the second opening penetrates the sidewall of the cap along the axial direction of the second through hole, and the second opening and the protrusion are arranged alternately in the circumferential direction.

6. A liquid chromatography system characterized by, The pipeline connector comprises: a pipeline with a sealing head; a target assembly comprising a liquid phase channel inlet with an internal thread; and the pipeline connector of any one of claims 1-5; wherein the pipeline comprises: a pipeline body made of metal, comprising a connecting end, the connecting end comprises a first section and a second section arranged adjacently, the first section comprises an end face perpendicular to the axis. The sealing member of plastic material comprises a first annular part and a second annular part coaxially arranged; the second annular part comprises a first surface facing the first annular part, and an axial projection of the first annular part falls within the first surface; the first surface comprises a first region surrounded by the axial projection and a second region surrounding the axial projection; the first annular part is radially extruded and sealingly arranged on an outer wall of the first section, and an end surface is axially extruded and sealingly arranged with the first region; an outer diameter of the second annular part increases first and then decreases along an axial direction repeatedly; the second annular part further comprises a second surface oppositely arranged with the first surface, and a side surface connecting the first surface and the second surface, and the second surface and the side surface are smoothly connected; and The sleeve of metal material is sleeved on the outer wall of the second section and the first annular part, and one side end surface of the sleeve abuts against the second region; the sleeve and the first annular part are at least partially in sliding fit; the sleeve comprises a first part sleeved on the outer wall of the second section and a second part sleeved on the outer wall of the first annular part; the first part comprises a first shrinkage part for fixing the sleeve and the second section, and / or the second part comprises a second shrinkage part for fixing the sleeve and the first annular part; The screw is sleeved on the outer wall of the pipeline; the other side end surface of the sleeve abuts against the first step structure; the screw and the liquid phase channel inlet are in threaded fit.

7. The liquid chromatography system of claim 6, wherein, In a direction gradually away from the second annular part, an outer diameter of the first annular part presents a decreasing trend, and an inner diameter of a section of the sleeve sleeved on the outer wall of the first annular part presents a decreasing trend.

8. The liquid chromatography system of claim 7, wherein, In a direction gradually away from the second annular part, an outer diameter of the first annular part presents an increasing trend; an inner wall of a section of the sleeve sleeved on the outer wall of the first annular part is cylindrical.

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