Method for manufacturing flow path unit

Abstract

A method for manufacturing a flow path unit (10) through which a high-temperature gas flows and which comprises a first metal body (1) having a first surface (11) and a second metal body (2) having a second surface (21), a flow path being formed by combining the first metal body (1) and the second metal body (2), the method comprising: a step for sandwiching a thermoplastic polyimide member (3) between the first surface (11) and the second surface (21); a step for applying pressure between the first surface (11) and the second surface (21); and a step for raising the temperature of the member (3) to the heat-resistance temperature of the thermoplastic polyimide or higher and thereby bonding the first metal body (1) and the second metal body (2) in a state in which the flow path is enclosed.

Description

Method for manufacturing a flow path unit

[0001] The present invention relates to a method for manufacturing a flow path unit.

[0002] 2. Description of the Related Art In a flow path unit provided in an analyzer, a gas generator, or the like, through which a fluid flows, sealing mechanisms are provided at various locations to prevent the fluid from leaking out.

[0003] Japanese Patent Application Laid-Open No. 2013-124673 (Patent Document 1) discloses that in a gas chromatography, which is an analytical device through which a sample gas flows, a fluororubber O-ring is used to seal the connection parts of the flow paths of each element to maintain airtightness.

[0004] JP 2013-124673 A

[0005] In gas analyzers and the like, gases with temperatures higher than the heat resistance temperature of materials commonly used for O-rings, such as fluororubber, are sometimes passed through, necessitating the development of sealing components with higher heat resistance temperatures. Resin O-rings filled with filler materials are also available, but they are expensive. While welding can be used to achieve sealing, a certain thickness is required for easy welding, which creates design constraints, especially for thin devices with microchannels.

[0006] The present disclosure has been made to solve such problems, and an object thereof is to provide a method for manufacturing a flow path unit that is highly heat resistant, inexpensive, and has few design restrictions.

[0007] A first aspect of the present invention is a method for manufacturing a flow path unit comprising a first metal body having a first surface and a second metal body having a second surface, the first metal body and the second metal body being joined to form a flow path through which high-temperature gas flows, the method comprising the steps of: sandwiching a member made of thermoplastic polyimide between the first surface and the second surface; applying pressure between the first surface and the second surface; and raising the temperature of the member to a temperature above the heat resistance temperature of the thermoplastic polyimide, thereby joining the first metal body and the second metal body while sealing the flow path.

[0008] According to the present disclosure, it is possible to manufacture a flow path unit that is highly heat resistant, inexpensive, and has few design restrictions.

[0009] FIG. 1 is a diagram for explaining features of a unit according to an embodiment; FIG. 2 is a flowchart showing a manufacturing process of a unit according to an embodiment; FIG. 3 is a schematic configuration diagram of an analytical device including a unit according to an embodiment; FIG. 4 is a cross-sectional view of a unit according to Example 1; FIG. 5 is a view of a unit according to Example 1 viewed obliquely from above; FIG. 6 is a view of a unit according to Example 1 viewed from below; FIG. 7 is an example of a polyimide sheet used in Example 1; FIG. 8 is an image diagram showing the configuration of a flow path plate according to Example 2; FIG. 9 is a view of a flow path plate according to Example 2 viewed from above; FIG. 10 is a diagram showing a state in which a manifold and a silicon device are mounted on a flow path plate according to Example 2; FIG. 11 is a cross-sectional view of a flow path plate according to a comparative example; FIG. 12 is a view showing the configuration of a unit according to Example 3;

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals and description thereof will not be repeated.

[0011] [Unit According to the Embodiment] FIG. 1 is a diagram illustrating features of a unit 10 according to the embodiment. The unit 10 includes a metal body 1 having a surface 11 and a metal body 2 having a surface 21. The metal bodies 1 and 2 are joined together to form a flow path through which high-temperature gas flows. The surfaces 11 and 12 correspond to examples of a "first surface" and a "second surface," respectively. A polyimide sheet 3 made of thermoplastic polyimide is sandwiched between the surfaces 11 and 12. The unit 10, the metal body 1, the metal body 2, and the polyimide sheet 3 correspond to examples of a "flow path unit," a "first metal body," a "second metal body," and a "thermoplastic polyimide member," respectively. The thermoplastic polyimide member may be made solely of thermoplastic polyimide, or may be primarily composed of thermoplastic polyimide and contain additives such as filler particles.

[0012] In this specification, the plane parallel to the polyimide sheet 3 is sometimes referred to as the XY plane, and the direction perpendicular to the XY plane is sometimes referred to as the Z-axis direction. Furthermore, the positive direction of the Z axis (the direction from metal body 2 toward metal body 1) is sometimes referred to as "upward," and the negative direction of the Z axis (the direction from metal body 1 toward metal body 2) is sometimes referred to as "downward."

[0013] In one embodiment, metal body 1 is a manifold having through holes for allowing a fluid to flow, and surface 11 is the surface of the manifold. Surface 11 is, more specifically, the area of ​​the surface of the manifold surrounding the through holes. Metal body 2 is a flow path plate having flow paths formed therein for allowing a fluid to flow, and surface 21 is the surface of the flow path plate. Surface 21 is, more specifically, the area of ​​the surface of the flow path plate surrounding holes for connecting flow paths inside the flow path plate to flow paths outside the flow path plate (for example, the through holes of the manifold).

[0014] In another embodiment, the metal bodies 1 and 2 are both flow channel plates, and the surfaces 11 and 12 are areas around holes for connecting the flow channels of the flow channel plates.

[0015] In yet another embodiment, metal body 1 is a pipe for flowing a fluid, surface 11 is a cross section thereof, and metal body 2 is a pipe for flowing a fluid, surface 21 is a cross section thereof.

[0016] In this specification, the connection of multiple components through which a fluid flows, as shown in these three examples, is referred to as a "fluid connection." More specifically, the fluid connection means that the fluid flow paths in the multiple components are connected to each other. In one example, the "fluid flow path" is a "gas flow path (gas flow path)."

[0017] The polyimide sheet 3 has thermoplastic properties that soften when heated. In one embodiment, the polyimide sheet 3 is a thin film member having surfaces 31 and 32 that face each other. In a more specific example, the polyimide sheet 3 is a Kapton (registered trademark) sheet. The heat resistance temperature of Kapton (registered trademark) sheets is publicly known to be 300°C. Here, the heat resistance temperature refers to a nominal value if available, or to the glass transition temperature of the material if no nominal value is available.

[0018] As will be described later with reference to Fig. 2, in the manufacturing process of unit 10, polyimide sheet 3 is sandwiched between surface 11 of metal body 1 and surface 21 of metal body 2, and polyimide sheet 3 is heated to a temperature equal to or higher than the heat resistance temperature of polyimide sheet 3 while being pressurized. This brings surface 11 and polyimide sheet 3, and surface 21 and polyimide sheet 3, into close contact. In this application, the above-mentioned "heating to a temperature equal to or higher than the heat resistance temperature while being pressurized" is also referred to as "thermocompression bonding."

[0019] The right side of Fig. 1 shows the state in which the polyimide sheet 3 and the metal body are tightly attached as a result of the thermocompression bonding. The polyimide sheet 3 is softened by heating and penetrates into the minute irregularities on the surface of the metal body, and the shape of the polyimide sheet 3 is fixed by cooling. This results in a strong welding between the metal body and the polyimide sheet 3 without any gaps.

[0020] [Method of Manufacturing Unit 10 According to the Embodiment] Fig. 2 is a flowchart showing a manufacturing process of a unit according to the embodiment. More specifically, Fig. 2 shows a method of manufacturing unit 10 including metal body 1 having surface 11 and surface 21, in which metal body 1 and metal body 2 are joined to form a flow path through which high-temperature gas flows. In one embodiment, each step (hereinafter also referred to as "ST") of Fig. 2 is performed by a processor of a device that manufactures unit 10 without user operation. In another embodiment, each step of Fig. 2 is performed manually by a user.

[0021] 2, in ST01, metal body 1 and metal body 2 are prepared. In ST02, polyimide sheet 3 made of thermoplastic polyimide is sandwiched between surface 11 of metal body 1 and surface 21 of metal body 2.

[0022] In ST03, pressure is applied between the surface 11 and the surface 21. In one embodiment, pressure is applied between the surface 11 and the surface 21 by fastening the metal body 1 and the metal body 2 with the polyimide sheet 3 sandwiched therebetween with a screw (see the screw 42 in FIG. 4 described later).

[0023] In ST04, the temperature of the polyimide sheet 3 is raised to or above the heat-resistant temperature of the thermoplastic polyimide, thereby bonding the metal body 1 and the metal body 2 together while sealing the flow path. Specifically, in ST04, the temperature of the polyimide sheet 3 is raised to a temperature lower than but close to the heat-resistant temperature of the thermoplastic polyimide, to the same temperature as the heat-resistant temperature, or to a temperature higher than the heat-resistant temperature. This allows the softened polyimide sheet 3 to penetrate into the minute irregularities on the metal surface. This firmly welds the metal body 1 and the metal body 2 together. This seals the gap between the metal body 1 and the metal body 2. As a result, even if the unit 10 is repeatedly heated, no fluid leaks from between the metal bodies 1 and 2. Therefore, even if a high-temperature gas (e.g., a gas heated by a column oven of a gas chromatograph (GC)) is repeatedly passed through the flow path of the unit 10, the high-temperature gas does not leak.

[0024] In one embodiment, when the polyimide sheet 3 is a Kapton® sheet, the temperature of the Kapton® sheet is raised to 300°C or higher in ST04. Specifically, in ST04, the temperature of the Kapton® sheet is raised to a temperature lower than but close to its heat-resistant temperature of 300°C, a temperature equal to the heat-resistant temperature, or a temperature higher than the heat-resistant temperature. In one embodiment, for example, the Kapton® sheet and / or the metal body 1 and the metal body 2 sandwiching the Kapton® sheet are heated at 310°C or higher and 340°C or lower for 10 minutes to 30 minutes. Heating in this manner firmly welds the metal bodies 1 and 2, creating a highly heat-resistant unit 10 that can withstand high-temperature gases approaching 300°C.

[0025] The processes of ST03 and ST04 may be started simultaneously, or one of them may be started first. The processes of ST03 and ST04 may be finished simultaneously, or one of them may be finished first. Preferably, the process is configured so that there is a time period during which the polyimide sheet 3 is kept pressed and the temperature of the polyimide sheet 3 reaches or exceeds the heat resistance temperature.

[0026] 2, the softened polyimide sheet 3 penetrates into the minute irregularities on the surface of the metal body, providing an anchoring effect and enabling a strong connection between the metal bodies. This provides a stronger seal between the two metal bodies than when a polyimide sheet is sandwiched between the two metal bodies and the seal is made within the elastic range of the polyimide sheet. This allows for a connection that does not cause fluid leakage.

[0027] [Analytical Device Including a Unit According to an Embodiment] In one embodiment, the unit 10 is part of an analytical device having a detector. A flow path that is fluidically connected to the detector is formed in the metal body 2. This configuration enables a highly heat-resistant, inexpensive fluid connection with fewer design constraints in an analytical device that analyzes fluids. The analytical device is, for example, a gas analyzer such as a GC or GC-MS (Gas Chromatography-Mass Spectrometry) that analyzes sample gases.

[0028] 3 is a schematic diagram of an analytical device 100 including a unit 10. In one embodiment, the analytical device 100 is a GC. The analytical device 100 is controlled by a control device 1000. The analytical device 100 includes carrier gas supply devices 61 to 63, a sample tank 60, a pump 65, a vent 64, a flow path plate unit 900, columns 71 to 74, and a detector 70.

[0029] Each of the carrier gas supply devices 61 to 63 adjusts a mobile phase called a carrier gas (for example, helium gas) to a predetermined pressure and outputs it.

[0030] The sample tank 60 is a device for storing sample gas to be analyzed. The sample gas is supplied to the flow path plate unit 900.

[0031] The pump 65 is a suction pump that sucks air from the sample loop 91 to create a negative pressure inside the sample loop 91 .

[0032] The vent 64 connects the flow path of the sample loop 91 to the outside, and discharges gas within the flow path of the sample loop 91 to the outside.

[0033] The flow channel plate unit 900 is formed by mounting a plurality of switching valves on a flow channel plate on which a flow channel pattern is formed. A sample loop 91 is formed on the flow channel plate (see FIG. 8).

[0034] The sample loop 91 temporarily holds the sample gas that is introduced into the column 71 for analysis. More specifically, the sample loop 91 has a gas flow path that meters and temporarily holds the sample gas before it is introduced into the column 71 for analysis.

[0035] The flow path plate also has a sampling module 92 formed thereon (see FIG. 8 ). In one embodiment, the sampling module 92 is a flow path other than the sample loop in the flow path plate. The sampling module is fluidly connected to the column 71 and the sample loop 91. The sampling module is also connected to the sample valve V1 and has a gas flow path that supplies sample gas from the sample valve V1 to the sample loop 91. The sampling module 92 then has a gas flow path that supplies the sample gas metered by the sample loop 91 to the column 71.

[0036] The columns 73 and 74 are pressure-regulating resistance tubes that are not capable of separating the various components of the sample gas.

[0037] Columns 71 and 72 separate various components in the supplied sample gas. Specifically, columns 71 and 72 separate and output various components contained in the supplied sample gas in the time direction while the supplied sample gas passes through each column with the flow of carrier gas. In this embodiment, column 71 is a column for primary separation. Column 72 is a column for secondary separation that further separates the various components of the sample gas that have been primarily separated by column 71. Columns 71 and 72 are heated by a column oven (not shown).

[0038] The outlet of column 72 is connected to confluence 75. The outlet of column 71 is connected to confluence 75 via flow path plate unit 900 and a resistance tube (column 74).

[0039] The detector 70 is connected to the confluence 75 and detects various gas components introduced from the confluence 75 .

[0040] The control device 1000 controls the analysis device 100. In one embodiment, the control device 1000 is a computer including a processor 1001 configured by a CPU (Central Processing Unit) or the like, and a memory 1002.

[0041] [Comparison between conventional fluid connections and fluid connections using a unit according to an embodiment] In gas analyzers, gases such as helium, nitrogen, and argon flow through metal piping, and techniques such as metal fittings and ferrules are sometimes used to connect the piping. However, these connection methods are large in size and require a large piping capacity.

[0042] Meanwhile, with the recent advances in analytical technology, in addition to the connection of carrier gases and auxiliary gases, the importance of connections between columns through which sample gases pass, including switching devices and other flow devices, has also increased. With the widespread use of capillary columns, there is a growing demand for lower-volume connections for sample gas connections. In particular, low-dead-volume connections are required for connections between microchannel devices and piping to capillary columns. Therefore, small-diameter ferrules and O-ring connections via manifolds are commonly used to connect microchannel devices to the piping. However, typical fluororubber O-rings have low heat resistance and cannot handle high-temperature gases. For example, typical O-rings cannot be used in connections in gas analyzers through which gas heated by a column oven flows. While some highly heat-resistant O-rings are known, they are extremely expensive (e.g., 10,000 to tens of thousands of yen).

[0043] For connection using a ferrule, it is necessary to provide a fixing portion for the ferrule on the microfluidic device side, which imposes constraints on the design of the microfluidic device.

[0044] Furthermore, for metal fitting, the area to be welded must have a sufficient thickness to prevent damage due to heat during welding, which places constraints on the design of the microchannel device.

[0045] On the other hand, the polyimide sheet 3 (e.g., Kapton (registered trademark) sheet) used in the unit 10 according to the embodiment has higher heat resistance than a typical O-ring. Furthermore, while highly heat-resistant O-rings are very expensive, the polyimide sheet 3 is relatively inexpensive (e.g., about 100 yen per sheet). Furthermore, while one O-ring is required to connect one flow path, one polyimide sheet 3 can connect multiple flow paths (see FIG. 7 , described later). Therefore, when using the polyimide sheet 3 to connect channels containing multiple flow paths, costs are significantly reduced (e.g., to one-hundredth of the cost) compared to when highly heat-resistant O-rings are used.

[0046] Furthermore, since connection using the polyimide sheet 3 can be achieved by simply sandwiching the thin polyimide sheet 3 between the two metal bodies to be connected, there are no design restrictions on the metal bodies, unlike connections using metal fittings, ferrules, etc.

[0047] Therefore, according to the method for manufacturing a unit according to the embodiment, it is possible to provide a method for manufacturing a flow path unit that is highly heat resistant, inexpensive, and has few design restrictions.

[0048] Furthermore, with conventional welding connections (metal fittings), it is difficult to remove the weld and replace some of the components of the unit. However, the polyimide sheet 3 bonded in the unit manufacturing method according to the embodiment can be easily peeled off as needed. This makes it easy to disassemble the unit 10 and replace some of the components of the unit 10. This facilitates maintenance of the unit 10 and the device including the unit 10.

[0049] Example 1 In Example 1, a manifold 1A and a flow path plate 2A are connected by thermocompression bonding with a polyimide sheet 3A. The unit 10A, the manifold 1A, the flow path plate 2A, and the polyimide sheet 3A correspond to examples of the "flow path unit," "first metal body," "second metal body," and "thermoplastic polyimide member," respectively.

[0050] Fig. 4 is a cross-sectional view of the unit 10A according to Example 1. Fig. 5 is a view of the unit 10A as seen obliquely from above. Fig. 6 is a view of the unit 10A as seen from below. Fig. 7 shows an example of a polyimide sheet 3A used in the unit 10A.

[0051] The unit 10A includes a manifold 1A, a flow path plate 2A, a polyimide sheet 3A, a back plate 41, screws 42, and a pipe 51.

[0052] The manifold 1A is a metal member having a plurality of through holes 19A formed therein. In one embodiment, the manifold 1A has opposing surfaces 11A and 12A, and the plurality of through holes 19A are formed so as to penetrate from the surface 11A to the surface 12A.

[0053] The flow path plate 2A is a metal plate having a gas flow path formed therein, and has holes 29A formed therein for connecting the internal flow path to the external flow path. In Fig. 4, only the position of the holes 29A is shown. The structure of the holes 29A is the same as that of the holes 29B in Fig. 9, which will be described later. The flow path plate 2A is positioned so that the holes 29A are located directly below the through-holes 19A.

[0054] In this example, a Kapton (registered trademark) sheet was used as the polyimide sheet 3A. The polyimide sheet 3A has surfaces 31A and 32A. A hole 39A for connecting the flow paths is formed in the polyimide sheet 3A. A hole 38A is also formed to pass through a positioning pin that fixes the polyimide sheet 3A in an appropriate position relative to the flow path plate 2A. The polyimide sheet 3A is positioned so that the hole 39A is located between the through-hole 19A and the hole 29A.

[0055] The polyimide sheet 3A is fabricated, for example, by forming holes 38A and 39A in a rectangular polyimide sheet indicated by 37A. In the example shown in FIG. 7 , edge portions 381A and 391A, which are the areas surrounding holes 38A and 39A that affect the flow path connections, and a connecting portion 36A, which is the portion connecting edge portions 381A and 391A, are left intact, while unnecessary portions 35A other than edge portions 381A and 391A and connecting portion 36A are removed. By leaving connecting portion 36A and integrally forming edge portions 381A and 391A, handling of edge portions 381A and 391A is easier than when edge portions 381A and 391A are formed separately, and it is also easier to position edge portions 381A and 391A in the appropriate positions. Furthermore, removing unnecessary portion 35A improves adhesion between edge portions 381A and 391A and manifold 1A and flow path plate 2A. However, in some embodiments, the unnecessary portion 35A may be used for bonding the metal body without being removed, which has the advantage of eliminating the step of removing the unnecessary portion 35A.

[0056] The back plate 41 is arranged so that when the manifold 1A, polyimide sheet 3A, and flow path plate 2A are fastened together with the screws 42, the fastening force is concentrated around the screws 42, preventing deformation of the flow path plate 2A. The back plate 41 is a metal plate having sufficient rigidity for this purpose.

[0057] The screws 42 fasten the manifold 1A, polyimide sheet 3A, and flow path plate 2A together, thereby compressing the surface 11A of the manifold 1A to the surface 31A of the polyimide sheet 3A, and compressing the surface 21A of the flow path plate 2A to the surface 32A of the polyimide sheet 3A.

[0058] The pipe 51 is a pipe for connecting a flow path outside the unit 10 with a flow path inside the unit 10 .

[0059] 4 to 6, openings 192A on the surface 12A side of the through holes 19A of the manifold 1A are connected to the pipes 51. Openings 191A on the surface 11A side of the through holes 19A are connected to holes 29A of the flow path plate 2A via holes 39A of the polyimide sheet 3A.

[0060] This allows the fluid from the pipe 51 to be introduced into the hole 29A via the through-hole 19A and the hole 39A. Also, the fluid from the hole 29A can be introduced into the pipe 51 via the hole 39A and the through-hole 19A.

[0061] In this example, the unit 10A was heated to 310°C or higher and 340°C or lower for 10 minutes or longer and 30 minutes or shorter while pressurized by the screws 42. After cooling, the unit 10A was repeatedly heated, but no fluid leakage occurred between the manifold 1A and the flow path plate 2A. The inventors found that the unit 10A could withstand repeated temperature increases at temperatures above 300°C without leakage, indicating that the unit 10A can withstand repeated temperature increases at temperatures at least up to 300°C. This achieved a highly heat-resistant and inexpensive fluid connection between the manifold 1A and the flow path plate 2A. In other words, the flow path plate 2A, which has a gas flow path for high-temperature gas, can be inexpensively connected to piping via the polyimide sheet 3A and the manifold 1A. Therefore, as specifically shown in Example 2 below, a method for inexpensively achieving a fluid connection between a flow path plate, which has a gas flow path formed therein, and piping used in a GC gas control system can be provided.

[0062] Example 2: The stainless steel (SUS) flow channel plate used in the gas control system of a GC can be molded into a single unit to integrate complex flow channels and complex piping, which has the great advantage of simplifying the assembly and adjustment of the flow channels.

[0063] In Example 2, manifolds 1B to 1D are thermocompression bonded to a flow path plate 2B used in the gas control system of a GC as described above using polyimide sheets 3B to 3D.

[0064] The unit 10B, manifolds 1B to 1D, flow path plate 2B, and polyimide sheets 3B to 3D correspond to an example of a "flow path unit," a "first metal body," a "second metal body," and a "thermoplastic polyimide member," respectively.

[0065] Fig. 8 is a conceptual diagram showing the configuration of a flow path plate 2B according to Example 2. Fig. 9 is a diagram showing the flow path plate 2B as viewed from above. Fig. 10 is a diagram showing a unit 10B in which manifolds 1B to 1D and a silicon device 52 are mounted on the flow path plate 2B.

[0066] The flow path plate 2B is a plate formed by joining a base plate 90 and a cover plate 99. In one embodiment, a sample loop 91 and a sampling module 92 are formed on the base plate 90 by half etching.

[0067] The cover plate 99 is joined to the side of the base plate 90 where the flow paths are formed. This protects the flow paths of the base plate 90 inside the flow path plate 2B. The cover plate 99 has multiple holes formed therein, as shown in the photograph in Figure 9.

[0068] 9 is a view of the flow path plate 2B as seen from the cover plate 99 side. Because the cover plate 99 is thin, the position of the flow path of the sample loop 91 is slightly recessed when the cover plate 99 and base plate 90 are joined, making it possible to determine the position of the sample loop 91. The flow path plate 2B (i.e., the base plate 90 and cover plate 99) has holes 28 formed therein through which the positioning pins 48 pass. The cover plate 99 also has holes 29B formed therein for connecting the flow paths within the flow path plate 2B with the flow paths outside the flow path plate 2B.

[0069] In FIG. 10, positioning pins 48 are used to fix the manifolds 1B to 1D at appropriate positions relative to the flow path plate 2B.

[0070] In one embodiment, manifold 1B fluidly connects the sample valve to flow plate 2B. Manifold 1C fluidly connects the analytical column to flow plate 2B.

[0071] During the manufacture of unit 10B, polyimide sheets 3B-3D are sandwiched between manifolds 1B-1D and flow path plate 2B, pressurized by screws 42B-42D, and heated to a temperature above their heat resistance temperature, thereby thermocompression bonding. In the example of Fig. 10, polyimide sheets 3B-3D are Kapton (registered trademark) sheets, and two sheets are used in a stack. Unit 10B and polyimide sheets 3B-3D correspond to an example of a "flow path unit" and an example of a "thermoplastic polyimide member," respectively.

[0072] The silicon device 52 is a microvalve having a laminated structure of silicon layers. The silicon device 52 has an inlet and an outlet for the sample gas, and the inlet and outlet can be switched between a connected state (open state) and a blocked state (closed state). The silicon device 52 is placed on the flow path plate 2B so that the sample gas flowing through the flow path in the flow path plate 2B flows through the silicon device 52. Specifically, the inlet of the silicon device 52 is placed directly above a predetermined hole 29B in the flow path plate 2B, and the outlet is placed directly above another hole 29B in the flow path plate 2B. With this configuration, the silicon device 52 can be used to appropriately block and control the flow of the sample gas in the flow path plate 2B.

[0073] Unit 10B is used, for example, as follows: Sample gas supplied from the sample valve passes through the through-holes in manifold 1B and is supplied to sample loop 91 in flow path plate 2B through hole 29B in cover plate 99. The sample gas measured in sample loop 91 flows into sampling module 92. The sample gas in sampling module 92 is controlled by silicon device 52 and flows again from hole 29B in cover plate 99 through the through-holes in manifold 1C to the analytical column. As described above, sample gas can be controlled using unit 10B. In particular, by thermocompression bonding polyimide sheets 3B to 3D, a highly heat-resistant, inexpensive, leak-free sample gas control unit can be provided.

[0074] 11 is a cross-sectional view of a flow path plate 2Z according to a comparative example. The flow path plate 2Z is ​​produced by etching a flow path for a sample loop 91Z and a flow path other than the sample loop (for example, a sampling module 92Z) into a single base plate 90Z, and then diffusion bonding a cover plate 99Z to the base plate 90Z.

[0075] 11 is a cross-sectional view of the flow path plate 2Z cut perpendicular to the direction of flow of the sample gas (Y direction), showing the width of the flow path (dimension in the X direction) and the depth of the flow path (dimension in the Z direction).

[0076] In half-etching, the depth of the flow path can only be made to about half the width of the flow path, and there is a technical limitation in that if the depth is made deeper, the shape of the flow path cannot be accurately maintained. Furthermore, in normal half-etching, the depth of the flow path that can be carved is fixed. Therefore, the depth of the flow path in the base plate 90Z is limited to about half the width of the narrowest flow path in the base plate 90Z.

[0077] In general, it is preferable that the flow paths other than the sample loop in the base plate 90 be relatively narrow in width to prevent widening due to diffusion. Specifically, it is preferable that the flow paths other than the sample loop be equivalent to the analytical column used. Therefore, the depth of the flow paths in the base plate 90Z is substantially limited to about half the width of the flow paths other than the sample loop.

[0078] On the other hand, the flow path of the sample loop 91Z needs to hold a predetermined volume of sample gas necessary for analyzing the sample gas. As a result, in order to ensure this predetermined volume in the sample loop 91Z, the width of the flow path of the sample loop 91Z is designed to be wider than the widths of the flow paths other than the sample loop.

[0079] 11, the depth of the flow path in the base plate 90Z is approximately 0.25, which is about half the width of the flow path in the sampling module 92Z, 0.5. The depth of the flow path in the sample loop 91Z is approximately 0.25, the same as that of the flow path in the sampling module 92Z, but the width is several times (for example, 2.0) that of the flow path in the sampling module 92Z, so that the required capacity can be maintained.

[0080] However, increasing the width of the flow path of the sample loop 91Z increases the aspect ratio of the flow path cross section of the sample loop 91Z. Here, the aspect ratio of the flow path cross section is the ratio of the flow path depth to the flow path width. In the example of FIG. 11 , the aspect ratio of the flow path cross section of the sample loop 91Z is 4 / 0.25=8. This aspect ratio is four times the aspect ratio of the flow path cross section of the sampling module 92Z, 0.5 / 0.2=2. When the aspect ratio of the flow path cross section increases, the linear velocity within the flow path becomes non-uniform. Here, linear velocity refers to the speed at which the sample gas passes through the cross-sectional area per unit time. More specifically, when the aspect ratio increases, the flow velocity in the center becomes relatively fast and the flow velocity at the ends becomes relatively slow relative to the flow path width. This can result in a decrease in the efficiency of gas replacement within the sample loop 91Z and a longer time required to inject the sample gas into the analytical column. As a result, in a GC including the flow path plate 2Z, carryover occurs due to poor replacement efficiency, and the bandwidth increases due to the increased injection time, which reduces the separation efficiency of the sample gas and reduces the analytical accuracy.

[0081] In Example 3, the sample loop 91E and the sampling module 92E are formed on separate plates (channel plates 2E1 and 2E2), so that the cross sections of the channels are formed with appropriate aspect ratios. The two plates (channel plates 2E1 and 2E2) are then thermocompression bonded together using a polyimide sheet 3E, thereby fluidly connecting the sample loop 91E and the sampling module 92E.

[0082] Fig. 12 is a diagram showing the configuration of a unit 10E according to Example 3. Fig. 13 is a cross-sectional view of the unit 10E.

[0083] 12 and 13, a unit 10E includes flow path plates 2E1 and 2E2 and a polyimide sheet 3E. Flow path plate 2E1 includes a base plate 90E1 and a cover plate 99E1. Flow path plate 2E2 includes a base plate 90E2 and a cover plate 99E2. A sample loop 91E and a sampling module 92E are formed on base plates 90E1 and 90E2, respectively. Unit 10E, flow path plate 2E1, flow path plate 2E2, and polyimide sheet 3E correspond to examples of a "flow path unit," a "first metal body," a "second metal body," and a "thermoplastic polyimide member," respectively.

[0084] The polyimide sheet 3E is, for example, a Kapton (registered trademark) sheet. The flow path plate 2E1 and the flow path plate 2E2 are bonded together using the method for manufacturing a unit according to the embodiment (FIG. 2). This allows for a highly heat-resistant, inexpensive, and strong bond between the flow path plate 2E1 and the flow path plate 2E2.

[0085] Specifically, for example, the surface 11E of the flow path plate 2E1 and the surface 21E of the flow path plate 2E2 are thermocompression-bonded at a position where a hole formed in the cover plate 99E1 for connecting the flow path inside the flow path plate 2E1 to the flow path outside the flow path plate 2E1 and a hole formed in the cover plate 99E2 for connecting the flow path inside the flow path plate 2E2 to the flow path outside the flow path plate 2E2 are connected. The surfaces 11E and 21E correspond to an example of a "first surface" and a "second surface." This allows the sample loop 91E in the flow path plate 2E1 and the sampling module 92E in the flow path plate 2E2 to be fluidly connected without leaking sample gas. This eliminates the need to worry about sample gas leakage or significant increases in cost that would occur if the sample loop 91E and the sampling module 92E were configured separately.

[0086] By constructing the sample loop 91E and the sampling module 92E as separate entities, it is easy to form the flow paths of the sample loop 91E and the sampling module 92E with different depths. Therefore, the cross-sectional flow paths of the sample loop 91E and the sampling module 92E can be formed with appropriate aspect ratios. For example, as shown in FIG. 13 , the flow path width and flow path depth of the sampling module 92E can be set to 0.5 and 0.25, respectively, and the flow path width and flow path depth of the sample loop 91E can be set to 1.0 and 0.5, respectively. In this case, the aspect ratios of the flow path cross-sections of the sampling module 92E and the sample loop 91E are both 2.0. This allows the aspect ratio of the sample loop 91E to be improved while maintaining the required capacity. Therefore, the occurrence rate of carryover and the increase in bandwidth can be suppressed compared to the comparative example. This improves the separation efficiency of the sample gas and the analytical accuracy compared to the comparative example.

[0087] As described above, according to Example 3, a flow path plate 2E1 having a sample loop formed therein and a flow path plate 2E2 having a sampling module formed therein were prepared, and flow path plate 2E1 and flow path plate 2E2 were bonded together by the method shown in Fig. 2, thereby enabling the manufacture of unit 10E that is highly heat-resistant, inexpensive, has few design restrictions, and can improve analytical accuracy. Therefore, according to Example 3, a method for manufacturing a unit that is highly heat-resistant, inexpensive, has few design restrictions, and can improve analytical accuracy was provided.

[0088] Furthermore, by forming the sample loop 91Z separately from the other flow paths, such as the sampling module 92E, it is possible to replace only the sample loop 91Z while leaving the other flow paths intact. Therefore, a sample loop 91Z of a type that matches the type of analytical column being used can be selected and used. Specifically, a sample loop 91Z with a capacity that matches the inner diameter and length of the column can be selected and used. In this case, there is no need to change the settings of the other flow paths, such as the sampling module 92E, while they remain connected to other parts of the GC.

[0089] Aspects It will be understood by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0090] (Item 1) A method for manufacturing a flow path unit comprising a first metal body having a first surface and a second metal body having a second surface, the first metal body and the second metal body being joined together to form a flow path through which high-temperature gas flows, the method comprising the steps of: sandwiching a thermoplastic polyimide member between the first surface and the second surface; applying pressure between the first surface and the second surface; and raising the temperature of the member to a temperature above the heat resistance temperature of the thermoplastic polyimide, thereby joining the first metal body and the second metal body while sealing the flow path.

[0091] According to the method described in the first paragraph, it is possible to provide a method for manufacturing a flow path unit that is highly heat-resistant, inexpensive, and has few design restrictions.

[0092] (Item 2) In the method according to item 1, the members are Kapton® sheets, and the bonding step includes raising the temperature of the Kapton® sheets to 300°C or higher.

[0093] According to the method described in the second paragraph, the metal body is firmly welded, and a highly heat-resistant flow passage unit that can withstand high-temperature gases of nearly 300°C can be produced.

[0094] (Item 3) In the method according to items 1 or 2, the flow path unit is part of an analytical device having a detector. A flow path is formed in the second metal body and is fluidly connected to the detector.

[0095] According to the method described in the third paragraph, in an analytical device (for example, GC or GC-MS) for analyzing a fluid, it is possible to achieve a fluid connection that is highly heat-resistant, inexpensive, and has few design restrictions.

[0096] (Item 4) In the method according to any one of Items 1 to 3, the flow path unit is part of a gas chromatograph having a column, and a sample loop that temporarily holds sample gas introduced into the column is formed in the first metal body, and a sampling module that is fluidly connected to the column and the sample loop is formed in the second metal body.

[0097] According to the method described in Section 4, the aspect ratio of the sample loop can be improved while maintaining the required volume in the sample loop. This makes it possible to achieve high heat resistance, low cost, fewer design constraints, and improved analytical accuracy.

[0098] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0099] 1, 2 Metal body, 1A, 1B, 1C, 1D Manifold, 2A, 2B, 2E1, 2E2, 2Z Flow path plate, 3, 3A to 3E Polyimide sheet, 10, 10A, 10B, 10E Unit, 11, 11A, 11E, 12, 12A, 21, 21A, 21E, 31, 31A, 32, 32A Surface, 19A Through hole, 28, 29A, 29B, 38A, 39A Hole, 35A Unnecessary part, 36A Connection part, 41 Back plate, 42, 42B, 42D Screw, 48 Positioning pin, 51 Piping, 52 Silicon device, 60 Sample tank, 61 to 63 Carrier gas supply device, 64 Vent, 65 Pump, 70 Detector, 71, 72, 73, 74 Column, 75 Junction, 90, 90E1, 90E2, 90Z base plate, 91, 91E, 91Z sample loop, 92, 92E, 92Z sampling module, 99, 99E2, 99E1, 99Z cover plate, 191A, 192A opening, 381A, 391A edge portion, 900 flow path plate unit, 1000 control device, 1001 processor, 1002 memory, V1 sample valve.

Claims

1. A method for manufacturing a flow path unit comprising a first metal body having a first surface and a second metal body having a second surface, the first metal body and the second metal body being joined to form a flow path through which high-temperature gas flows, the method comprising the steps of: sandwiching a thermoplastic polyimide member between the first surface and the second surface; applying pressure between the first surface and the second surface; and raising the temperature of the member to a temperature above the heat resistance temperature of the thermoplastic polyimide, thereby bonding the first metal body and the second metal body while sealing the flow path.

2. The method of claim 1, wherein the member is a Kapton® sheet, and the bonding step includes raising the temperature of the Kapton® sheet to 300°C or higher.

3. The method according to claim 1, wherein the flow path unit is part of an analytical device having a detector, and the second metal body has a flow path formed therein that is fluidly connected to the detector.

4. The method according to claim 1, wherein the flow path unit is part of a gas chromatograph having a column, the first metal body is formed with a sample loop for temporarily holding sample gas introduced into the column, and the second metal body is formed with a sampling module that is fluidly connected to the column and the sample loop.

Images