Chromatography tube

Abstract

To provide a tube used for chromatography piping, consisting of a resin tube covered with a metal tube, which makes the resin tube portion less susceptible to damage and enables reliable sealing.SOLUTION: A chromatography tube 1 is provided, consisting of a synthetic resin tube 2 covered with a metal tube 3, where the untreated synthetic resin tube 2 protrudes from the metal tube 3 at a tip end of the tube 1.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a tube for a chromatograph and a piping system for a chromatograph.

Background Art

[0002] Conventionally, a tube, which is a pipe for a chromatograph forming a flow path of a chromatograph, is connected to a connector using a ferrule and a nut, and connects between components of the chromatograph (Patent Document 1).

[0003] However, when piping the tube using a ferrule, there is a problem that a dead volume is likely to occur at the connection portion with the connector, which affects the chromatogram. Also, when piping the tube using a ferrule, there is a problem that the sealing area between the ferrule and the connector is wide and seal leakage is likely to occur. Also, at the time of connection, it is necessary to insert the tube into the through holes of the ferrule and the nut and connect them using a tightening tool or the like, so there is a problem that the connection is complicated and requires a strong force.

[0004] Also, as a configuration for piping a tube without using a ferrule, a plug unit using a capillary having an outer covering portion of a hard material surrounding a deformable inner covering portion has been proposed. This plug unit includes a deformable ring-shaped sealing member in the front end region of the capillary, the inner covering portion protrudes from the outer covering portion, and the inner covering portion has a front end region that extends radially outward, and the front end region generates a sealing action alone or together with the sealing member. And the plug unit further includes a pressing body that covers the capillary and abuts against the sealing member, and a plug housing for connecting the capillary and the pressing body to the bush unit, and a configuration has been proposed in which the plug housing is screwed into the bush unit to connect the capillary to the plug housing (Patent Document 2).

[0005] In addition, in the invention described in Patent Document 2, the edge of the opening of the end face of the metal tube is chamfered so that the load when the front end region of the inner coating portion, that is, the flange portion is pressed, is less likely to concentrate on a specific portion. However, it is not easy to perform the chamfering process with high precision. Also, since the flange portion is supported by a resin sealing member, it is said that sufficient pressure resistance performance cannot be maintained. A pipe has been proposed in which the inner wall of the flow path is composed of a resin tube and the outer peripheral surface thereof is covered with a metal tube. Specifically, the pipe is extended by a metal tube with an end extension member whose tip is chamfered, which is composed of a material harder than the resin tube and includes a first member and a second member. The resin tube protrudes from the metal tube and the end extension member and is bent along the chamfered shape to form a flange portion at the end of the pipe (Patent Document 3).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] As described above, when using ferrules for tube piping, there are problems such as seal leakage being likely to occur, a large number of parts, complicated connections, and the need for strong force.

[0008] In addition, in the inventions described in Patent Document 2 and Patent Document 3, since the resin tube protrudes long from the metal tube and extends outward to form a flange, and since it is bent, the original thickness and strength of the resin tube are lost. Therefore, even if chamfering is performed, the resin tube portion is likely to be damaged and seal leakage is likely to occur. In addition, there is a problem that the number of parts of the tube itself is large, the structure is complex, and it is difficult to assemble and manufacture accurately as a tube with a very small inner diameter. Further, in the invention described in Patent Document 3, there is a problem that the number of parts of the tube itself and the parts for piping is large, the structure is complex, and the connection is complicated.

[0009] Therefore, an object of the present invention is to be able to connect with a simple configuration easily and with a little force without using ferrules in the piping of a chromatograph. Another object is to provide a tube in which a resin tube used for the piping of a chromatograph is coated with a metal tube, and in which the resin tube portion is hardly damaged and can be surely sealed. Another object is to provide a tube in which a resin tube used for the piping of a chromatograph is coated with a metal tube, and in which the number of parts of the tube itself is small, the structure is simple, and it can be easily assembled and manufactured. Another object is to provide a piping system in which the number of parts of the tube itself and the parts for piping is small and the connection is easy in the piping of a chromatograph.

Means for Solving the Problems

[0010] The present invention for solving the above problems is a chromatograph tube in which a synthetic resin tube is coated with a metal tube, and the tip of the tube is a chromatograph tube in which the synthetic resin tube protrudes from the metal tube in an unprocessed state.

[0011] A chromatographic tube in which a synthetic resin tube is coated with a metal tube, wherein the tip of the tube has the synthetic resin tube protruding from the metal tube, and the cross-sectional shape in a direction orthogonal to the longitudinal direction of the synthetic resin tube is the same for the portion coated with the metal tube and the portion protruding from the metal tube.

[0012] Also, in the above chromatographic tube, the tip of the tube has the synthetic resin tube protruding 0.1 mm or more and 0.3 mm or less from the metal tube.

[0013] Also, in the above chromatographic tube, the tip of the tube has the synthetic resin tube protruding 0.15 mm or more and 0.25 mm or less from the metal tube.

[0014] A chromatographic tube in which a synthetic resin tube is coated with a metal tube, characterized in that the tip of the tube has the synthetic resin tube protruding 0.1 mm or more and 0.3 mm or less from the metal tube.

[0015] A chromatographic tube in which a synthetic resin tube is coated with a metal tube, characterized in that the tip of the tube has the synthetic resin tube protruding 0.15 mm or more and 0.25 mm or less from the metal tube.

[0016] Also, in the above chromatographic tube, the outer surface of the metal tube is provided with locking protrusions for engaging the chromatographic tube with a fitting.

[0017] Also, in the above chromatographic tube, the synthetic resin tube is made of polyetheretherketone, and the metal tube is made of stainless steel.

[0018] Also, a synthetic resin tube is inserted into a metal tube, and with the synthetic resin tube inserted into the metal tube, it is inserted into a die and pulled, stretching and narrowing the metal tube while closely adhering it to the synthetic resin tube, covering the synthetic resin tube with the metal tube, cutting it to a predetermined length, and cutting the metal tubes at both ends of the tube covered with the synthetic resin tube by the metal tube by a length that allows the synthetic resin tube to protrude, and manufacturing by protruding the synthetic resin tube from the metal tube. This is a method for manufacturing a tube for chromatography.

[0019] Also, in the method for manufacturing a tube for chromatography as described above, a method for manufacturing a tube for chromatography in which no processing is performed on the portion of the synthetic resin tube that protrudes from the metal tube.

[0020] Also, in the method for manufacturing a tube for chromatography as described above, a method for manufacturing a tube for chromatography in which the length of the portion of the synthetic resin tube that protrudes from the metal tube is 0.1 mm or more and 0.3 mm or less.

[0021] Also, in the method for manufacturing a tube for chromatography as described above, a method for manufacturing a tube for chromatography in which the length of the portion of the synthetic resin tube that protrudes from the metal tube is 0.15 mm or more and 0.25 mm or less.

[0022] Further, it includes the above-described chromatography tube and a fitting for connecting the chromatography tube to a connector. On the outer surfaces of both ends of the chromatography tube, there are locking projections for engaging with the fitting. The fitting includes a front end portion and a rear end portion having a larger diameter than the front end portion. The outer surface of the front end portion has a male thread, and the outer surface of the rear end portion is knurled. It includes an installation groove extending from the side surface toward the center for installing the chromatography tube at the center of the fitting. At the tip of the installation groove, there is a locking recess for locking the locking projection. The locking projection is inserted into the locking recess, and the chromatography tube is installed along the central axis of the fitting in a manner that it can be inserted and removed from the installation groove. This is a piping system for chromatography.

[0023] Furthermore, it is a piping structure for installing a tube in a chromatograph, which includes the above-described piping system for chromatography and a connector. The connector includes an installation recess for installing the piping system for chromatography and a through hole communicating with the installation recess. The installation recess is configured to include a piping installation portion and a connecting portion where a female thread is formed, starting from the through hole side. With the locking projection of the chromatography tube locked to the locking recess of the fitting, the front end portion of the fitting is screwed into the connecting portion of the connector, and the piping system is inserted and installed in the installation recess. The chromatography tube is inserted and installed in the piping installation portion. The bottom surface of the piping installation portion and the end surface of the synthetic resin tube protruding from the metal tube, which is the tip of the chromatography tube, are in contact, and the through hole communicates with the flow path of the chromatography tube. This is the piping structure of the chromatograph.

[0024] Furthermore, in the above-described piping structure of the chromatograph, the synthetic resin tube is made of polyether ether ketone. This is a piping structure for chromatography.

Advantages of the Invention

[0025] According to the present invention as described above, in the piping of the chromatograph, it has become possible to easily connect with a simple configuration and with little force without using ferrules. Also, it has become possible to provide a tube for use in the piping of a chromatograph, which is a tube in which a resin tube is coated with a metal tube, and in which the resin tube portion is difficult to break and can be reliably sealed. Also, it has become possible to provide a tube for use in the piping of a chromatograph, which is a tube in which a resin tube is coated with a metal tube, and which has a small number of parts, a simple structure, and can be easily assembled and manufactured. Also, in the piping of the chromatograph, it has become possible to provide a piping system with a small number of parts and easy connection.

Brief Description of the Drawings

[0026]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0027] The tube for a chromatograph of the present invention is a tube for a chromatograph in which a synthetic resin tube is coated with a metal tube, and the tip of the tube is a tube for a chromatograph in which the synthetic resin tube protrudes from the metal tube in an unprocessed state. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0028] Furthermore, the chromatograph using the tube for chromatograph of the present invention includes a liquid chromatograph, a supercritical fluid chromatograph, and a gas chromatograph. In the present embodiment, the configuration of the liquid chromatograph will be described. As shown in FIG. 1, the liquid chromatograph 100 includes a liquid feed pump 140 provided with a liquid feed pump control device for supplying the mobile phase 111 in the mobile phase container 110 to the flow path 130 including the separation column 120, a sample injection flow path switching valve, a sample loop, etc., and a sample injection device 150 for supplying a predetermined amount of sample to the flow path 130 in a timely manner, a separation column 120 for separating the sample into components, a detector 160 provided with a detector cell 161 for detecting the sample components separated by the separation column 120, a pipe 170 for connecting these, and a liquid chromatograph control device 180 for controlling the liquid chromatograph.

[0029] Furthermore, the liquid chromatograph of the present invention includes an analytical liquid chromatograph (a liquid chromatograph used at a flow rate of less than 5 mL / min) and a preparative liquid chromatograph (a liquid chromatograph used at a flow rate of 5 mL / min or more). Also included are a low-pressure liquid chromatograph or a medium-pressure liquid chromatograph (a liquid chromatograph performed under a pressure of around 0.5 to 3.0 MPa) and a high-performance liquid chromatograph (also called a high-speed liquid chromatograph or HPLC. A liquid chromatograph performed under a pressure of up to 40 MPa) and an ultra-high-performance liquid chromatograph (also called an ultra-high-speed liquid chromatograph or UHPLC. A liquid chromatograph performed under a pressure greater than 40 MPa and up to 200 MPa).

[0030] As shown in FIGS. 2 and 3, the tube 1 for a chromatograph of the present invention (hereinafter referred to as "tube 1") is configured by covering a synthetic resin tube 2 with a metal tube 3. The tube 1 constitutes a pipe 170 that forms a part of the flow path 130 in the liquid chromatograph 100 shown in FIG. 1. The synthetic resin tube 2 is cylindrical with a hollow flow path 21 in the longitudinal direction, the metal tube 3 is cylindrical with a hollow portion 32 that houses the synthetic resin tube 2 in the longitudinal direction, and the tube 1 is cylindrical. The flow path 21 of the synthetic resin tube 2 constitutes a part of the flow path 130 in the liquid chromatograph 100.

[0031] At both ends of the tube 1, the synthetic resin tube 2 protrudes from the metal tube 3 in an unprocessed state. The unprocessed state means a state in which no processing other than the processing for making the synthetic resin tube 2 a predetermined length is performed, and the portion 23 of the synthetic resin tube 2 protruding from the metal tube 3 is not subjected to physical processing such as bending or spreading, or other processing that changes the shape other than processing that shortens the length. And the processing for adjusting the length of the synthetic resin tube 2 to a predetermined length includes processing for flattening the end face of the synthetic resin tube 2 and processing for adjusting the angle of the end face of the synthetic resin tube 2 with respect to the longitudinal direction of the tube 1. Incidentally, the processing for making the synthetic resin tube 2 a predetermined length includes cutting, cutting, and grinding.

[0032] The end face of the protruding portion 23 of the synthetic resin tube 2 is configured to be orthogonal to the central axis in the longitudinal direction of the tube 1. Also, the cross-sectional shape in the direction orthogonal to the longitudinal direction of the synthetic resin tube 2 is the same everywhere in the portion 28 covered by the metal tube 3 and the portion 23 protruding from the metal tube 3, including the end face of the protruding portion 23. Therefore, the portion 23 of the synthetic resin tube 2 protruding from the metal tube 3 is also cylindrical. Also, the diameter of the cross-section in the direction orthogonal to the longitudinal direction of the synthetic resin tube 2 is the same everywhere. The portion 23 of the synthetic resin tube 2 protruding from the metal tube 3 constitutes a sealing member for maintaining liquid tightness at the connection surface with the connector to which the tube 1 is connected.

[0033] In this way, at both ends of the tube 1, since the synthetic resin tube 2 protrudes from the metal tube 3 in an unprocessed state, there are no thin-walled portions or stretched or bent portions, so the synthetic resin tube 2 is difficult to break and can surely perform sealing. Also, the structure of the tube 1 is simple and can be easily manufactured. Also, there is an advantage that the structure of the tube 1 is simple, the connection is easy, and the handling is easy.

[0034] By configuring the end face of the protruding portion 23 of the synthetic resin tube 2 to be orthogonal to the central axis in the longitudinal direction of the tube 1, it is possible to more surely maintain liquid tightness at the connection surface with the connector to which the tube 1 is connected. Incidentally, the end face of the protruding portion 23 of the synthetic resin tube 2 can also be configured not to be orthogonal to the central axis in the longitudinal direction of the tube 1.

[0035] The size of the tube 1 is not particularly limited as long as it can be used in a chromatograph. As an example, the inner diameter of the synthetic resin tube 2 is 0.1 mm, the outer diameter is 1.4 mm, the length is 300 mm, the inner diameter of the metal tube 3 is 1.4 mm, the outer diameter is 1.59 mm, and the length is 299.6 mm. Also, as another example, the inner diameter of the synthetic resin tube 2 is 0.2 mm, the outer diameter is 1.4 mm, the length is 300 mm, the inner diameter of the metal tube 3 is 1.4 mm, the outer diameter is 1.59 mm, and the length is 299.6 mm.

[0036] At the tip of the tube 1, the length L of the protruding portion 23 where the synthetic resin tube 2 protrudes from the metal tube 3 is 0.1 mm or more and 0.3 mm or less. If the length L of the protruding portion 23 is less than 0.1 mm, the tip of the synthetic resin tube 2 is less likely to be in close contact with the connection surface with the connector over the outer circumference, and sufficient sealing cannot be achieved. Also, if the length L of the protruding portion 23 is longer than 0.3 mm, when pressed against the connection surface with the connector, the synthetic resin tube 2 will be crushed, bulge inward, the inner diameter of the flow path will become thinner, and the inner diameters of the flow path 21 of the tube 1 and the pipe 170 will become non-uniform. Also, since the protruding portion 23 is not evenly crushed and a displacement occurs on the connection surface with the connector, sufficient sealing cannot be achieved. The protruding length L of the protruding portion 23 of the synthetic resin tube 2 is preferably 0.15 mm or more and 0.25 mm or less. This is because the tip of the synthetic resin tube 2 is more likely to be in close contact with the connection surface with the connector over the outer circumference, the deformation of the protruding portion 23 is less, and more reliable sealing can be achieved.

[0037] And at both tips of the tube 1, since the synthetic resin tube 2 protrudes from the metal tube 3 in an unprocessed state and the length L of the protruding portion 23 is 0.1 mm or more and 0.3 mm or less, the resin tube 3 is less likely to be damaged, the inner diameters of the flow path 21 of the tube 1 and the pipe 170 can be more reliably maintained uniformly, and further, sealing can be more reliably performed.

[0038] On the outer surface 37 of the metal tube 3 at both ends of the tube 1, there are locking projections 13 for the tube 1 to engage with a fitting described later. The locking projection 13 is an annular projection extending over the entire circumference of the outer surface 37 of the metal tube 3. Incidentally, if the locking projection 13 can engage with the fitting, it may be one or a plurality of projections formed on a part of the outer surface 37. The locking projection 13 is made of the same material as the metal tube 3 and is fixed to the outer surface 37 of the metal tube 3 by welding, such as laser welding or TIG welding, or adhesion. By providing the locking projection 13, when connecting the tube 1 to the connector 7, by simply inserting and screwing the fitting into the connector 7, the tip of the synthetic resin tube 2 can be surely pressed against the connector 7 to form a sealed state.

[0039] The material of the synthetic resin tube 2 is not particularly limited as long as it has pressure resistance that can withstand use in a chromatograph, except in cases where chemical resistance, inertness, etc. are required depending on the use conditions. The synthetic resin tube 2 can be made of, but is not limited to, polyetheretherketone (PEEK), polytetrafluoroethylene (PTFE), or perfluoroalkoxyalkane (PFA). This is because it is excellent in chemical resistance, inertness, pressure resistance, and wear resistance, and also has preferable elasticity and flexibility as a sealing member. Also, the material of the metal tube 3 is not particularly limited as long as it is made of metal, but since it is excellent in chemical resistance and rust prevention, it is preferably made of stainless steel.

[0040] Next, a method for manufacturing the tube 1 will be described. First, a synthetic resin tube is manufactured. The method for manufacturing the synthetic resin tube can adopt a known method and is not particularly limited, but it can be manufactured by extrusion molding. Next, a metal tube is manufactured. The method for manufacturing the metal tube can adopt a known method and is not particularly limited, but the plate material is welded while being rounded, or the molten material is extruded or drawn to form a tube, and the tube is made thicker than the diameter at the time of completion and expanded to an inner diameter into which the synthetic resin tube can be inserted. Then, the synthetic resin tube is inserted into the metal tube, and while being inserted into the die in a state where the synthetic resin tube is inserted into the metal tube, it is pulled, the metal tube is expanded and thinned to the outer diameter at the time of completion, and is brought into close contact with the synthetic resin tube to coat the synthetic resin tube with the metal tube. Then, it is cut to a predetermined length. At this point, the synthetic resin tube does not protrude from both ends of the tube coated with the metal tube, and both end faces are flush.

[0041] Next, the metal tubes at both ends of the tube are cut by the length by which the synthetic resin tube protrudes. Then, if necessary, the tip portion of the synthetic resin tube 2 is cut or ground in order to adjust the length of the portion 23 protruding from the metal tube 3 of the synthetic resin tube 2 to a predetermined length. By this processing, the end face of the synthetic resin tube 2 can be made flatter, and the angle with the longitudinal direction of the tube 1 can also be adjusted. Finally, the locking projection 13 is fixed to the outer surface 37 of the metal tube 3 by welding such as laser welding or TIG welding, or welding, etc., to manufacture the tube 1. In this way, the tube 1 in which the synthetic resin tube 2 protrudes straight from the metal tube 3 is completed.

[0042] In the manufacturing process of tube 1, after the synthetic resin tube is cut together with the metal tube while being coated with the metal tube, no processing other than the processing for making the synthetic resin tube 2 into a predetermined length is performed on the synthetic resin tube. Specifically, the metal tube is cut by the length by which the synthetic resin tube protrudes, and after the synthetic resin tube protrudes, no physical processing such as bending or stretching, or other processing for changing the shape other than the processing for shortening the length is performed on the portion 23 protruding from the metal tube 3 of the synthetic resin tube 2. Incidentally, as described above, the processing for making the synthetic resin tube 2 into a predetermined length includes the processing for flattening the end face of the synthetic resin tube 2 and the processing for adjusting the angle between the end face of the synthetic resin tube 2 and the longitudinal direction of the tube 1.

[0043] As shown in FIGS. 4 and 5, tube 1 engages with fitting 5 to form a chromatograph piping system 8 (hereinafter referred to as "piping system 8"), and is connected to connector 7 as shown in FIG. 6. Fitting 5 is a component for connecting tube 1 to connector 7, and connector 7 is a part of a component of a chromatogram, and includes components for connecting the component to a pipe, components for connecting pipes to each other, and components for connecting a component of a chromatogram to a pipe. For example, it includes column nuts, valves, valve stators, adapters, unions, joints, and the like.

[0044] The fitting 5 is a cylindrical pressing screw having a front end portion 51 and a rear end portion 52. The front end portion 51 has a male thread on the outer surface 551, and the rear end portion 52 has a larger diameter than the front end portion 51. The outer surface 552 is knurled to form a knob portion. Incidentally, the rear end portion 52 may have the same diameter as the front end portion 51, or may have a smaller diameter than the front end portion 51. Further, the fitting 5 is provided with an installation groove 53 for installing the tube 1 at the center of a cross section orthogonal to the front-rear direction of the fitting 5. The installation groove 53 extends from the front end to the rear end of the fitting 5 in the direction from the side surface 55 toward the center, and the tube 1 can be installed so as to be insertable and removable along the central axis of the fitting 5. Further, at the tip portion on the front end portion 51 side of the installation groove 53, there is provided a locking recess 59 formed by a recess capable of accommodating the locking projection 13 of the tube 1 for locking the locking projection 13 of the tube 1.

[0045] The lateral width W of the installation groove 53 is larger than the diameter of the portion of the tube 1 other than the locking projection 13 and has a length less than the diameter of the locking projection 13. The portion of the tube 1 other than the locking projection 13 can be inserted, but the locking projection 13 cannot be inserted. Incidentally, the portion corresponding to the locking recess 59 of the installation groove 53 may be configured to have a diameter equal to or larger than the diameter of the locking projection 13, and the locking projection 13 portion may also be configured to be insertable into the installation groove 53 from the side surface 55 of the fitting 5 toward the center. However, in such a configuration, the fitting 5 is likely to come off from the tube 1. Therefore, in order to make it difficult to come off, it is preferable that the lateral width W of the installation groove 53 is configured to have a width into which the locking projection 13 cannot be inserted.

[0046] In the piping system 8, the end portion of the tube 1 is inserted into the installation groove 53 of the fitting 5, the locking projection 13 is inserted into the locking recess 59, and the portion of the tube 1 on the tip side of the locking projection 13 protrudes from the tip of the fitting 5. In this state, the central axis of the tube 1 and the central axis of the fitting 5 are aligned and assembled. When assembling, first, the portion inside the locking projection 13 of the tube 1 is inserted into the installation groove 53, and the fitting 5 is slid in the tip direction of the tube 1 to insert the locking projection 13 into the locking recess 59.

[0047] As shown in Fig. 6, the connector 7 includes an installation recess 70 for installing the tube 1 and the fitting 5, and a through hole 71 communicating with the installation recess 70. The installation recess 70 includes a pipe installation portion 72 into which the tube 1 is inserted from the side of the through hole 71, and a connection portion 73 formed with a female thread into which the front end portion 51 of the fitting 5 is inserted and which is connected to the connector 7. The through hole 71, the pipe installation portion 72, and the connection portion 73 are columnar with the central axes aligned, and are configured to have a stepped larger diameter from the through hole 71 toward the connection portion 73.

[0048] When connecting the piping system 8 to the connector 7, the piping system 8 assembled with the end of the tube 1 inserted into the installation groove 53 of the fitting 5 is inserted into the installation recess 70 of the connector 7 from the end of the tube 1, the tube 1 is inserted and installed in the pipe installation portion 72, and the bottom surface 721 of the pipe installation portion 72 faces the tip of the tube 1, specifically, the end face 27 of the synthetic resin tube 2 protruding from the metal tube 3. Then, the operator manually grips and rotates the rear end portion 52 of the fitting 5 with knurling, and the front end portion 51 of the fitting 5 formed with a male thread is screwed into the connection portion 73 formed with a thread to fix the tube 1 and the fitting 5 to the connector 7.

[0049] When the front end portion 51 of the fitting 5 is screwed into the connection portion 73 of the connector 7, the locking projection 13 of the tube 1 is locked and pressed against the bottom surface 591 of the locking recess 59 of the fitting 5, and the tube 1 advances in the direction of the through hole 71 within the installation recess 70 of the connector 7 together with the fitting 5. Then, the bottom surface 721 of the pipe installation portion 72 abuts against the end face 27 of the synthetic resin tube 2 protruding from the metal tube 3. And the through hole 71 forming the flow path 130 of the liquid chromatograph 100 communicates with the flow path 21 of the tube 1.

[0050] After the bottom surface 721 of the pipe installation part 72 and the end surface 27 of the synthetic resin tube 2 protruding from the metal tube 3 come into contact, further, by screwing in and advancing the fitting 5, the protruding part 23 of the synthetic resin tube 2 is pressed against the bottom surface 721 of the pipe installation part 72, the end surface 27 is in close contact, and sealing is performed at the end surface 27 of the synthetic resin tube 2.

[0051] At this time, the protruding part 23 of the synthetic resin tube 2 protruding from the metal tube 3 has no change in the inner diameter of the flow path 21, there is no displacement on the connection surface with the connector 7, and sufficient sealing can be performed. Also, since the flow path 21 and the through hole 71 are directly connected and sealed by the synthetic resin tube 2 constituting the flow path 21, no dead volume is generated. Further, in pipe connection, by simply rotating the rear end part 52 of the fitting 5 by hand of an operator, reliable connection and sealing can be performed with simple operation and less force.

Industrial Applicability

[0052] According to the present invention as described above, by adopting a piping system for a chromatograph using a tube for a chromatograph, liquid leakage can be prevented at the pipe connection part of the chromatogram, and the pipes can be easily connected. Therefore, it can be used in various industries that require analysis by a chromatogram.

Explanation of Reference Numerals

[0053] 1 Tube 13 Locking Projection 2 Synthetic Resin Tube 21 Flow Path 23 Protruding Part 3 Metal Tube 5 Fitting 53 Installation Groove 59 Locking Recess 7 Connector 70 Installation Recess 71 Through Hole 8 Piping System for Chromatograph 100 Liquid Chromatograph 170 piping

Claims

1. A chromatography tube in which a synthetic resin tube is coated with a metal tube, wherein the tip of the tube is characterized in that the synthetic resin tube protrudes from the metal tube in an unprocessed state.

2. A chromatography tube in which a synthetic resin tube is coated with a metal tube, wherein the tip of the tube is such that the synthetic resin tube protrudes from the metal tube, and the cross-sectional shape in a direction perpendicular to the longitudinal direction of the synthetic resin tube is the same in the portion covered by the metal tube and the portion protruding from the metal tube.

3. A chromatography tube in which a synthetic resin tube is coated with a metal tube, wherein the tip of the tube is characterized in that the synthetic resin tube protrudes 0.1 mm or more and 0.3 mm or less from the metal tube.

4. A chromatography tube in which a synthetic resin tube is coated with a metal tube, wherein the tip of the tube is characterized in that the synthetic resin tube protrudes 0.1 mm or more and 0.3 mm or less from the metal tube in an unprocessed state.

5. A chromatography tube in which a synthetic resin tube is coated with a metal tube, wherein the tip of the tube is such that the synthetic resin tube protrudes 0.1 mm or more and 0.3 mm or less from the metal tube, and the cross-sectional shape in a direction perpendicular to the longitudinal direction of the synthetic resin tube is the same in the portion covered by the metal tube and the portion protruding from the metal tube.

6. A chromatography tube in which a synthetic resin tube is coated with a metal tube, wherein the tip of the tube is characterized in that the synthetic resin tube protrudes 0.15 mm or more and 0.25 mm or less from the metal tube.

7. A chromatography tube in which a synthetic resin tube is coated with a metal tube, wherein the tip of the tube is characterized in that the synthetic resin tube protrudes 0.15 mm or more and 0.25 mm or less from the metal tube in an unprocessed state.

8. A chromatography tube in which a synthetic resin tube is coated with a metal tube, wherein the tip of the tube has the synthetic resin tube protruding 0.15 mm or more and 0.25 mm or less from the metal tube, and the cross-sectional shape in a direction orthogonal to the longitudinal direction of the synthetic resin tube is the same in the portion covered by the metal tube and the portion protruding from the metal tube. A chromatography tube characterized by this.

9. The chromatography tube according to any one of claims 1 to 8, characterized in that the outer surface of the metal tube is provided with locking projections for engaging the chromatography tube with a fitting.

10. The chromatography tube according to any one of claims 1 to 8, characterized in that the synthetic resin tube is made of polyether ether ketone and the metal tube is made of stainless steel.

11. A method for manufacturing a chromatography tube, comprising inserting a synthetic resin tube into a metal tube, inserting the metal tube with the synthetic resin tube inserted into a die and pulling it to expand and narrow the metal tube, bringing it into close contact with the synthetic resin tube, coating the synthetic resin tube with the metal tube, cutting it to a predetermined length, and cutting the metal tubes at both ends of the tube coated with the synthetic resin tube by the metal tube by the length by which the synthetic resin tube protrudes, so that the synthetic resin tube protrudes from the metal tube.

12. The method for manufacturing a chromatography tube according to claim 11, characterized in that no processing is performed on the portion of the synthetic resin tube protruding from the metal tube.

13. The method for manufacturing a chromatography tube according to claim 11 or 12, characterized in that the length of the portion of the synthetic resin tube protruding from the metal tube is 0.1 mm or more and 0.3 mm or less.

14. The method for manufacturing a chromatography tube according to claim 11 or 12, characterized in that the length of the portion of the synthetic resin tube protruding from the metal tube is 0.15 mm or more and 0.25 mm or less.

15. A chromatograph tube according to any one of claims 1 to 8, and a fitting for connecting the chromatograph tube to a connector. Outer surfaces of both ends of the chromatograph tube are provided with locking protrusions for engaging with the fitting. The fitting includes a front end portion and a rear end portion having a larger diameter than the front end portion. The outer surface of the front end portion is provided with a male thread, and the outer surface of the rear end portion is knurled. The fitting is provided with an installation groove extending from the side surface in the central direction for installing the chromatograph tube at the center of the fitting. The tip of the installation groove is provided with a locking recess for locking the locking protrusion. The locking protrusion is inserted into the locking recess, and the chromatograph tube is installed along the central axis of the fitting so as to be insertable and removable from the installation groove. A piping system for a chromatograph, characterized in that.

16. A piping structure for installing a tube in a chromatograph, comprising the piping system for a chromatograph according to claim 15 and a connector. The connector includes an installation recess for installing the piping system for a chromatograph and a through hole communicating with the installation recess. The installation recess is configured to include a piping installation portion and a connecting portion formed with an internal thread from the side of the through hole. With the locking protrusion of the chromatograph tube locked to the locking recess of the fitting, the front end portion of the fitting is screwed into the connecting portion of the connector, and the piping system is inserted and installed in the installation recess. The chromatograph tube is inserted and installed in the piping installation portion. The bottom surface of the piping installation portion and the end surface of the synthetic resin tube protruding from the metal tube, which is the tip of the chromatograph tube, are in contact with each other, and the through hole communicates with the flow path of the chromatograph tube. A piping structure of a chromatograph, characterized in that.

17. The piping structure for a chromatograph according to claim 16, characterized in that the synthetic resin tube is made of polyether ether ketone.

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