Pipe structure of heat exchanger and manufacturing method of the same

Abstract

To provide a pipe structure of a heat exchanger which can reduce complexity of a manufacturing process and inhibit heat degradation of a member in the manufacturing process and enables separation of a double pipe portion, and to provide a manufacturing method of the pipe structure.SOLUTION: Spaces between each manifold 4A, 4B into which an inner pipe 2 is inserted and an outer pipe 3 are sealed by annular seal materials S1, and screw parts 4g of the manifolds 4A, 4B and screw parts 7c of the connection bodies 7A, 7B are threadedly engaged. Tapered cylinder parts 6a of connection inner pipes 6 inserted into flare parts 2a, 2b and the flare parts 2a, 2b are pressed from the outer periphery side by inner peripheral surfaces of tapered through holes 4e of the manifold 4A, 4B to cause the tapered cylinder parts 6a, the flare parts 2a, 2b, and the inner peripheral surfaces of the tapered through holes 4e to be integrated and be firmly attached to each other and seal spaces between the manifolds 4A, 4B and the inner pipe 2. Each of the manifolds 4A, 4B is sandwiched between the connection body 7A, 7B and a longitudinal end of the outer pipe 3 to restrict movement in a longitudinal direction. Pipe bodies 5a, 5b are connected to the respective manifolds 4A, 4B by brazing.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a piping structure of a heat exchanger and a manufacturing method thereof, and more particularly to a piping structure of a heat exchanger that can eliminate the complexity of the manufacturing process, suppress thermal deterioration of components during the manufacturing process, and enable separation of the double tube portion, and a manufacturing method thereof. [Background technology]

[0002] Various piping structures for heat exchangers have been proposed (see, for example, Patent Document 1). Patent Document 1 describes a double-pipe structure in which a condenser 320 is disposed on the outer periphery of an aluminum alloy pipe 205 between an evaporator 204 and a compressor 201 (see paragraph 0035, Figs. 1 to 8, etc. of Patent Document 1). In the piping structure described in Patent Document 1, end caps 322 and 323 that close both ends of a main body 321 of the condenser 320 are connected to the pipe 205 by brazing. In addition, a refrigerant pipe 330 is connected to the end cap 323 by brazing.

[0003] Conventionally, brazing has been used to improve sealing, but the brazing process requires a lot of time. In addition, there is a risk of thermal degradation of the components heated during the brazing process. Furthermore, the double-pipe portion cannot be partially replaced because it is brazed. Therefore, there is room for improvement in manufacturing the piping structure of a heat exchanger to reduce the number of brazed parts to eliminate the complexity of the manufacturing process, suppress thermal degradation of the components during the manufacturing process, and make the double-pipe portion separable. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-148374 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a piping structure for a heat exchanger and a manufacturing method thereof that can eliminate the complexity of the manufacturing process, suppress thermal deterioration of components during the manufacturing process, and enable the double pipe portion to be separated. [Means for solving the problem]

[0006] In order to achieve the above object, the piping structure of a heat exchanger of the present invention has an inner pipe and an outer pipe forming a double pipe structure, a cylindrical manifold that is inserted around the inner pipe and installed at both longitudinal ends of the outer pipe, and pipe bodies brazed to each of the manifolds, and the longitudinal ends of the outer pipe are sealed by each of the manifolds, a flow path of each of the pipe bodies is connected to an internal space of the brazed manifold, a flow path between an outer peripheral surface of the inner pipe and an inner peripheral surface of the outer pipe, and a flow path of each of the manifolds is connected to an internal space of the manifold. The piping structure of the heat exchanger in which the outer peripheral region of the inner pipe communicates with the manifold in a space includes an annular seal material for the outer pipe interposed between each of the manifolds and the outer pipe, one connecting inner pipe connected to one longitudinal end of the inner pipe, the other connecting inner pipe connected to the other longitudinal end of the inner pipe, one cylindrical coupling body inserted onto the one connecting inner pipe, and the other cylindrical coupling body inserted onto the other connecting inner pipe, and flare portions are formed at both longitudinal ends of the inner pipe, and the length of each of the connecting inner pipes facing each of the flare portions is provided with a sealing material for the outer pipe. a threaded portion is formed on the outer peripheral surface of the longitudinal end of each of the manifolds, and a tapered through hole extending in the longitudinal direction is formed on the inner peripheral surface thereof, and when the threaded portion of one of the manifolds and the threaded portion of one of the connecting bodies are screwed together, the tapered tube portion inserted into one of the flare portions and its flare portion are pressed from the outer periphery by the inner peripheral surface of the tapered through hole of one of the manifolds, so that the tapered tube portion, its flare portion and its tapered through hole are pressed from the outer periphery by the inner peripheral surface of the tapered through hole of one of the manifolds, one of the manifolds is sandwiched between the one of the connecting bodies and one longitudinal end of the outer tube and is installed such that longitudinal movement is restricted, and the threaded portion of the other of the manifolds is screwed into the threaded portion of the other of the connecting bodies, whereby the tapered cylindrical portion and the flare portion inserted into the flare portion of the other of the manifolds are pressed from the outer circumferential side by the inner circumferential surface of the tapered through hole of the other of the manifolds, so that the tapered cylindrical portion, the flare portion, and the inner circumferential surface of the tapered through hole are integrated and tightly attached to each other,The other manifold is sandwiched between the other connecting body and the other end of the outer pipe in the longitudinal direction, and is installed such that movement in the longitudinal direction is restricted.

[0007] The present invention relates to a method for manufacturing a piping structure of a heat exchanger, the piping structure of the heat exchanger having a double-pipe structure of an inner pipe and an outer pipe, a cylindrical manifold that is inserted onto the inner pipe and installed at both longitudinal ends of the outer pipe, and a tube body brazed to each of the manifolds, the method comprising the steps of: preparing one connecting inner pipe connected to one longitudinal end of the inner pipe; another connecting inner pipe connected to the other longitudinal end of the inner pipe; one cylindrical connecting body that is inserted onto the one connecting inner pipe; and another cylindrical connecting body that is inserted onto the other connecting inner pipe; a threaded portion is formed on the outer peripheral surface of a longitudinal end of each of the manifolds, and a tapered through hole extending in the longitudinal direction is formed on the inner peripheral surface, one longitudinal end of each of the connecting inner tubes is formed into a tapered cylindrical portion, one flared portion is formed on one longitudinal end of the inner tube, one of the manifolds is fitted onto the inner tube so that the one flared portion and the inner peripheral surface of the tapered through hole of one of the manifolds are abutted against each other, the outer tube is fitted onto the inner tube, and then the other manifold is fitted onto the inner tube, and the outer tube is fitted onto each of the manifolds. a second flare portion is formed at the other longitudinal end of the inner tube, and the other flare portion is brought into contact with the inner peripheral surface of the tapered through hole of the other manifold. The threaded portion of one of the manifolds is screwed into the threaded portion of one of the coupling bodies, and the tapered tubular portion of one of the connecting inner tubes inserted into the one flare portion and its flare portion are screwed into the threaded portion of one of the manifolds. the tapered tubular portion and its flared portion are pressed from the outer periphery by the inner periphery of the tapered through hole of the hold, the tapered tubular portion and its flared portion are integrated and tightly attached to the inner periphery of the tapered through hole, one of the manifolds is clamped between the one of the connecting bodies and one longitudinal end of the outer pipe to restrict longitudinal movement and installed, the threaded portion of the other manifold is screwed into the threaded portion of the other connecting body, and the tapered tubular portion and its flared portion of the other connecting inner pipe inserted into the flared portion of the other are pressed from the outer periphery by the inner periphery of the tapered through hole of the other manifold,The tapered tubular portion, the flared portion, and the inner peripheral surface of the tapered through hole are integrated and tightly attached, the other manifold is sandwiched between the other connecting body and the other longitudinal end of the outer tube to restrict longitudinal movement, and a flow path between the outer peripheral surface of the inner tube and the inner peripheral surface of the outer tube communicates with an outer peripheral region of the inner tube in the internal space of one of the manifolds and the other of the manifolds, a flow path of one of the tube bodies brazed to one of the manifolds communicates with the internal space of one of the manifolds, and a flow path of the other tube body brazed to the other manifold communicates with the internal space of the other of the manifolds. Effect of the Invention

[0008] According to the present invention, each of the manifolds can be installed together with the outer pipe by using the respective connectors arranged at two positions spaced apart in the longitudinal direction of the inner pipe, while restricting the longitudinal movement of the manifolds and the outer pipe, and the gap between each of the manifolds and the outer pipe is sealed by the respective annular seal materials for the outer pipe. Also, the gap between each of the manifolds and the inner pipe is sealed by integrating and closely contacting the tapered tubular portion of each of the connecting inner pipes, the corresponding flared portion of the inner pipe, and the inner peripheral surface of the corresponding tapered through hole of the manifold. The brazing work is only required to connect each of the manifolds and each of the pipe bodies, so that the complexity of the manufacturing process of this piping structure can be eliminated. Accordingly, it is advantageous to suppress the thermal deterioration of the inner pipe and the outer pipe during this manufacturing process.

[0009] The connectors connected to the manifolds can be separated by unscrewing the threads of each other. Accordingly, the double pipe portion formed by the inner pipe and the outer pipe can be separated from each of the connectors and the connecting inner pipe, and this double pipe portion can be separated from each of the manifolds. Therefore, part of this piping structure can be replaced as necessary. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is an explanatory diagram illustrating an embodiment of a piping structure of a heat exchanger as viewed from the front; [Diagram 2] 2 is an explanatory diagram illustrating the piping structure of FIG. 1 in a vertical cross-sectional view. [Diagram 3] 3 is a cross-sectional view taken along line AA in FIG. 2. [Figure 4] 3 is an explanatory diagram illustrating a state in which one connector and one manifold in FIG. 2 are separated, and the other connector and the other manifold are connected. FIG. [Diagram 5] 2 is an explanatory diagram illustrating an inner pipe before the piping structure of FIG. 1 is manufactured, as viewed from the front with a lower half in cross section. [Figure 6] 6 is an explanatory view illustrating a step of forming one of the flared portions in the inner tube of FIG. 5. FIG. [Figure 7] 7 is an explanatory view illustrating a process of extrapolating one manifold onto the inner tube of FIG. 6. FIG. [Figure 8] 8 is an explanatory view illustrating a process of inserting an outer tube onto the inner tube of FIG. 7. [Figure 9] 9 is an explanatory view illustrating a process of extrapolating the other manifold onto the inner tube of FIG. 8. FIG. [Figure 10] 10 is an explanatory view illustrating a state in which a reamer is being inserted into the other longitudinal portion of the inner tube in a state in which the other manifold is abutted against the other longitudinal end of the outer tube in FIG. 9. FIG. [Figure 11] 11 is an explanatory view illustrating a step of forming the other flare portion in the inner pipe of FIG. 10. FIG. [Figure 12] 12 is an explanatory diagram illustrating a process of screwing connectors to the respective manifolds in FIG. 11. FIG. [Figure 13] 13 is an explanatory diagram illustrating a part of another embodiment of a piping structure in a vertical cross-sectional view. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a piping structure for a heat exchanger and a method for manufacturing the same according to the present invention will be described based on an embodiment shown in the drawings.

[0012] The embodiment of the piping structure of the heat exchanger 1 illustrated in Figs. 1 to 4 includes an inner pipe 2 and an outer pipe 3 constituting a double pipe structure, two cylindrical manifolds 4A, 4B, and two pipes 5a, 5b. Furthermore, this piping structure includes annular seal members S1, S1 for the outer pipe interposed between each of the manifolds 4A, 4B and the outer pipe 3, two connecting inner pipes 6, 6, and two cylindrical connecting bodies 7A, 7B. One manifold 4A, the outer pipe 3, and the other manifold 4B are arranged and installed in order between one connecting body 7A and the other connecting body 7B. One connecting inner pipe 6 is fitted on one connecting inner pipe, and the other connecting body 7B is fitted on the other connecting inner pipe. One connecting inner pipe 6 is connected to one end of the inner pipe 2 in the longitudinal direction, and the other connecting inner pipe 6 is connected to the other end of the inner pipe 2 in the longitudinal direction. The dashed dotted line CL in the figure indicates the cylindrical axis of the inner tube 2, the outer tube 3, the manifolds 4A and 4B, and the connectors 7A and 7B.

[0013] The inner tube 2, manifolds 4A, 4B, tube bodies 5a, 5b, connecting inner tubes 6, 6, and connectors 7A, 7B are each made of metal and are formed of known materials, while the outer tube 3 is made of metal or a polymeric material such as resin and is formed of known materials. Although the outer tube 3 may be made of stainless steel, the inner tube 2, outer tube 3, manifolds 4A, 4B, tube bodies 5a, 5b, connecting inner tubes 6, 6, and connectors 7A, 7B are preferably made of similar materials, for example, aluminum or an aluminum alloy, and these parts are preferably made of similar materials.

[0014] The sizes of the inner pipe 2, outer pipe 3, and pipe bodies 5a, 5b vary depending on the performance required of the heat exchanger 1, but the outer diameter of the inner pipe 2 is, for example, about 4 mm or more and 500 mm or less, the outer diameter of the outer pipe 3 is, for example, about 8 mm or more and 500 mm or less, and the outer diameter of the pipe bodies 5a, 5b is, for example, about 4 mm or more and 500 mm or less. The sizes of the manifolds 4A, 4B, the connecting inner pipes 6, 6, and the coupling bodies 7A, 7B are appropriately set based on the sizes of the inner pipe 2 and the outer pipe 3, etc.

[0015] Cylindrical flare portions 2a, 2b that expand in diameter toward the longitudinal ends are formed at both longitudinal ends of the inner pipe 2. The flare portions 2a, 2b are formed by processing the inner pipe 2.

[0016] Each of the manifolds 4A, 4B is fitted onto the inner tube 2 and installed at both longitudinal ends of the outer tube 3. Each of the manifolds 4A, 4B has a through hole 4c, a through hole 4d, and a tapered through hole 4e between one end and the other end in the cylindrical axis direction, and an internal space P3 is formed between the through holes 4c and 4d in the cylindrical axis direction. In this embodiment, each of the manifolds 4A, 4B has a cylindrical flange portion 4f with a reduced diameter at one end in the cylindrical axis direction, and the inner peripheral surface of this flange portion 4f forms the through hole 4c.

[0017] Further, a threaded portion 4g, 4g is formed on the outer peripheral surface of each of the manifolds 4A, 4B at the longitudinal end, and a tapered through hole 4e, 4e extending in the longitudinal direction is formed on the inner peripheral surface of the threaded portion 4b. That is, the outer peripheral side of each of the tapered through holes 4e, 4e is the threaded portion 4g, 4g.

[0018] One of the connecting inner pipes 6 is connected to one longitudinal end (flare portion 2a) of the inner pipe 2. The other connecting inner pipe 6 is connected to the other longitudinal end (flare portion 2b) of the inner pipe 2. The longitudinal ends of each of the connecting inner pipes 6, 6 facing the respective flared portions 2a, 2b are formed into tapered cylindrical portions 6a, 6a with reduced diameters. Each of the tapered cylindrical portions 6a, 6a is inserted into the opposing flared portions 2a, 2b.

[0019] A threaded portion 7c is formed on the cylindrical inner peripheral surface of each of the connectors 7A and 7B. One of the connecting inner tubes 6 is inserted into the connector 7A, and the other of the connecting inner tubes 6 is inserted into the connector 7B.

[0020] In this embodiment, each connecting inner pipe 6 has a bead portion 6b that protrudes outward from the outer circumferential surface near the tapered tubular portion 6a. Each bead portion 6b extends in an annular shape in the circumferential direction on the outer circumferential surface of the connecting inner pipe 6. The bead portion 6b is formed by processing the connecting inner pipe 6. The bead portion 6b may be formed by a known method. For example, the bead portion 6b is formed by performing bead processing (stringing processing) on ​​the connecting inner pipe 6 to cause a part of the connecting inner pipe 6 to protrude outward.

[0021] The protruding height of the bead portion 6b toward the outer periphery may be any height capable of restricting the movement of the connectors 7A, 7B in one longitudinal direction that are extrapolated to the connecting inner tube 6. The protruding height of the bead portion 6b varies depending on the outer diameter of the connecting inner tube 6, but is, for example, 2 mm or more. The bead portion 6b is not limited to the specifications exemplified in this embodiment, and may be any height capable of restricting the movement of the connectors 7A, 7B in one longitudinal direction of the connecting inner tube 6.

[0022] By screwing the threaded portion 4g (male threaded portion) of one manifold 4A with the threaded portion 7c (female threaded portion) of one connecting body 7A, the tapered tube portion 6a inserted into the flare portion 2a on one side and the flare portion 2a thereof are pressed from the outer periphery by the inner periphery of the tapered through hole 4e of one manifold 4A, and the tapered tube portion 6a, the flare portion 2a, and the inner periphery of the tapered through hole 4e of the one manifold 4A are integrated and in close contact with each other. Similarly, by screwing the threaded portion 4g (male threaded portion) of the other manifold 4B with the threaded portion 7c (female threaded portion) of the other connecting body 7B, the tapered tube portion 6a inserted into the flare portion 2b on the other side and the flare portion 2b thereof are pressed from the outer periphery by the inner periphery of the tapered through hole 4e of the other manifold 4B, and the tapered tube portion 6a, the flare portion 2b, and the inner periphery of the tapered through hole 4e of the other manifold 4B are integrated and in close contact with each other.

[0023] The inner pipe 2 communicates with the tapered through-holes 4e, through-holes 4d, and through-holes 4c of one manifold 4A and the through-holes 4c, through-holes 4d, and tapered through-holes 4e of the other manifold 4B. The flange portion 4f of one manifold 4A is inserted into one end of the outer pipe 3 in the longitudinal direction, and the flange portion 4f of the other manifold 4B is inserted into the other end of the outer pipe 3 in the longitudinal direction. Both ends of the outer pipe 3 in the longitudinal direction are sealed by the manifolds 4A and 4B. It is preferable to make the gap between the inner circumferential surface of the outer pipe 3 and the outer circumferential surface of each flange portion 4f as small as possible, for example, 1 mm or less. It is also preferable to make the gap between the outer circumferential surface of the inner pipe 2 and the inner circumferential surface of each through-hole 4d as small as possible, for example, 1 mm or less.

[0024] More specifically, sealing materials S1, S1 are interposed between each of the manifolds 4A, 4B and the outer pipe 3. In this embodiment, sealing materials S1, S1 are disposed between the outer peripheral surface of each of the flange portions 4f, 4f and the inner peripheral surface of the outer pipe 3 to seal the gaps therebetween.

[0025] Various known sealing materials that seal gaps airtightly can be used for the sealing material S1. Specifically, O-rings made of various known elastic materials such as silicone rubber, various gaskets, various packings, various adhesives, and the like can be used as the sealing material S1.

[0026] The outer peripheral surface of the tapered tubular portion 6a of one of the connecting inner pipes 6 and the inner peripheral surface of one of the flared portions 2a are in close contact with each other to hermetically seal the gap therebetween (metal seal). Also, the outer peripheral surface of one of the flared portions 2a and the inner peripheral surface of the tapered through hole 4e of one of the manifolds 4A are in close contact with each other to hermetically seal the gap therebetween (metal seal). Similarly, the outer peripheral surface of the tapered tubular portion 6a of the other of the connecting inner pipes 6 and the inner peripheral surface of the other flared portion 2b are in close contact with each other to hermetically seal the gap therebetween (metal seal). Also, the outer peripheral surface of the other flared portion 2b and the inner peripheral surface of the tapered through hole 4e of the other manifold 4B are in close contact with each other to hermetically seal the gap therebetween (metal seal).

[0027] One longitudinal end face of the outer pipe 3 abuts against an end face of one manifold 4A that is more outer than the flange portion 4f. Similarly, the other longitudinal end face of the outer pipe 3 abuts against an end face of the other manifold 4B that is more outer than the flange portion 4f.

[0028] In this piping structure, one manifold 4A is sandwiched between one connecting body 7A and one longitudinal end of the outer pipe 3, and installed with its longitudinal movement restricted. The other manifold 4B is sandwiched between the other connecting body 7B and the other longitudinal end of the outer pipe 3, and installed with its longitudinal movement restricted. Therefore, one manifold 4A, the outer pipe 3, and the other manifold 4B are installed between the connecting body 7A and the connecting body 7B, and are substantially fixed with respect to the longitudinal direction of the inner pipe 2.

[0029] One tube 5a is brazed to the outer circumferential surface of one manifold 4A, and the other tube 5b is brazed to the outer circumferential surface of the other manifold 4b. These manifolds 4A, 4B and the tubes 5a, 5b are brazed using a known brazing material suitable for the materials thereof.

[0030] The flow path P2 of one tube body 5a communicates with the internal space P3 of one manifold 4A brazed to the tube body 5a. The flow path P2 of the other tube body 5b communicates with the internal space P3 of the other manifold 4B brazed to the tube body 5b. The flow path P1 between the outer peripheral surface of the inner tube 2 and the inner peripheral surface of the outer tube 3 communicates with the outer peripheral side region of the inner tube 2 in the internal spaces P3, P3 of each manifold 4A, 4B. Therefore, the flow path P2 of one tube body 5a communicates with the outer peripheral side region of the inner tube 2 in the internal space P3 of one manifold 4A, the flow path P1 between the outer peripheral surface of the inner tube 2 and the inner peripheral surface of the outer tube 3, the outer peripheral side region of the inner tube 2 in the internal space P3 of the other manifold 4B, and the flow path P2 of the other tube body 5b. The flow paths of each connecting inner tube 6, 6 communicate with the flow path of the inner tube 2.

[0031] As illustrated in FIG. 2, the high-temperature fluid HF flows from the flow path P2 of one tube body 5a through the outer peripheral region of the inner tube 2 in the internal space P3 of one manifold 4A, the flow path P1 between the outer peripheral surface of the inner tube 2 and the inner peripheral surface of the outer tube 3, the outer peripheral region of the inner tube 2 in the internal space P3 of the other manifold 4B, and into the flow path P2 of the other tube body 5b. The low-temperature fluid LF flows from the flow path of one connecting inner tube 6 through the flow path of the inner tube 2 to the flow path of the other connecting inner tube 6. Between the inner tube 2 and the outer tube 3 of the double-tube structure, the thermal energy of the high-temperature fluid HF is transferred to the low-temperature fluid LF, so that the temperature of the high-temperature fluid HF decreases and the temperature of the low-temperature fluid LF increases. In this way, in the heat exchanger 1, heat exchange is performed between the high-temperature fluid HF and the low-temperature fluid LF. This heat exchanger 1 is applied to, for example, air conditioners installed in vehicles such as automobiles, and air conditioners installed in houses, factories, and various facilities.

[0032] An example of a procedure for manufacturing the piping structure of the heat exchanger 1 will now be described.

[0033] As shown in Fig. 5, an inner pipe 2 of a predetermined length is prepared. Next, as shown in Fig. 6, a reamer 8 is inserted into one longitudinal end of the inner pipe 2 to form one flare portion 2a, which expands in diameter toward the outer periphery, at one longitudinal end of the inner pipe 2. The flare portion 2a may be formed by various known methods.

[0034] Next, as shown in Fig. 7, one manifold 4A is fitted onto the inner pipe 2. A sealant S1 is attached to this manifold 4A in advance. Also, one tube 5a is brazed to the outer circumferential surface of the manifold 4A. As shown in Fig. 8, the outer circumferential surface of one flare portion 2a is brought into contact with the inner circumferential surface of the tapered through hole 4e of the fitted manifold 4A.

[0035] Next, as shown in Fig. 8, the outer tube 3 is fitted onto the inner tube 2, and the longitudinal end face of the outer tube 3 facing the manifold 4A is abutted against the end face of the manifold 4A as shown in Fig. 9. Next, as shown in Fig. 9, the other manifold 4A is fitted onto the inner tube 2. A seal material S1 is attached to this manifold 4B in advance. In addition, the other tube body 5b is brazed to the outer circumferential surface of the manifold 4B.

[0036] As illustrated in Figure 10, the longitudinal end face of the outer tube 3 facing the manifold 4B is abutted against the end face of the manifold 4B, and at the position where the outer tube 3 is sandwiched between each of the manifolds 4A, 4B, the spaces between each of the manifolds 4A, 4B and the outer tube 3 are sealed with each of the sealing materials S1, S1, and both longitudinal ends of the outer tube 3 are sealed by each of the manifolds 4A, 4B.

[0037] Next, as illustrated in Fig. 10, a reamer 8 is inserted into the other longitudinal end of the inner tube 2 to form the other flare portion 2b at the other longitudinal end of the inner tube 2. This causes the outer peripheral surface of the other flare portion 2b to abut against the inner peripheral surface of the tapered through hole 4e of the other manifold 4B, as illustrated in Fig. 11.

[0038] Next, as illustrated in Fig. 12, the threaded portion 4g of one manifold 4A and the threaded portion 7c of one connecting body 7A that is fitted onto one connecting inner tube 6 are screwed together. As a result, the tapered tube portion 6a of one connecting inner tube 6 inserted into one flare portion 2a and its flare portion 2a are pressed from the outer periphery by the inner periphery of the tapered through hole 4e of one manifold 4A, and the tapered tube portion 6a, its flare portion 2a and its inner periphery of the tapered through hole 4e are integrated and tightly attached. As a result, the outer periphery of the tapered tube portion 6a and the inner periphery of one flare portion 2a are tightly attached to each other, and the gap between them is airtightly sealed (metal sealed), and the outer periphery of one flare portion 2a and the inner periphery of the tapered through hole 4e of one manifold 4A are tightly attached to each other, and the gap between them is airtightly sealed (metal sealed). Then, one manifold 4A is sandwiched between one connector 7A and one longitudinal end of the outer tube 3, and is installed so as to restrict movement in the longitudinal direction.

[0039] Similarly, the threaded portion 4g of the other manifold 4B is screwed into the threaded portion 7c of the other connecting body 7B, and the tapered tubular portion 6a and its flare portion 2b of the other connecting inner tube 6 inserted into the other flare portion 2b are pressed from the outer periphery by the inner circumferential circle of the tapered through hole 4e of the other manifold 4B, so that the tapered tubular portion 6a, its flare portion 2b, and its inner circumferential surface of the tapered through hole 4e are integrated and tightly attached. As a result, the outer circumferential surface of the tapered tubular portion 6a of the other connecting inner tube 6 and the inner circumferential surface of the other flare portion 2b are tightly attached to each other, and the gap between them is airtightly sealed (metal sealed), and the outer circumferential surface of the other flare portion 2b and the inner circumferential surface of the tapered through hole 4e of the other manifold 4B are tightly attached to each other, and the gap between them is airtightly sealed (metal sealed). The other manifold 4B is then sandwiched between the other connecting body 7B and the other longitudinal end of the outer tube 3, and is installed with its longitudinal movement restricted.

[0040] In this manner, a piping structure as illustrated in FIG. 2 is manufactured, in which one manifold 4A, the outer pipe 3, and the other manifold 4B are arranged in sequence between one connecting body 7A and the other connecting body 7B.

[0041] According to the piping structure of the heat exchanger 1 described above, the manifolds 4A, 4B can be installed together with the outer pipe 3 while restricting their longitudinal movement by using the connecting bodies 7A, 7B arranged at two positions spaced apart in the longitudinal direction of the inner pipe 2. In addition, the manifolds 4A, 4B and the outer pipe 3 are sealed by the respective sealing materials S1, S1. The tapered tubular parts 6a, 6a of the connecting inner pipes 6, 6, the corresponding flared parts 2a, 2b of the inner pipe 2, and the inner peripheral surfaces of the tapered through holes 4e of the corresponding manifolds 4A, 4B are integrated and tightly attached to each other, thereby sealing the manifolds 4A, 4B and the inner pipe 2. The brazing work is only required for the connection between the manifolds 4A, 4B and the corresponding pipe bodies 5a, 5b. The work of brazing and connecting while ensuring airtightness takes a long time and requires high skill. Therefore, this embodiment, which requires only two brazing points, contributes greatly to eliminating the complexity of the manufacturing process of this piping structure. Accordingly, in this manufacturing process, the inner pipe 2 and the outer pipe 3 are not heated by the brazing work, which is advantageous in suppressing thermal deterioration of the inner pipe 2 and the outer pipe 3.

[0042] One manifold 4A and one connecting body 7A, and the other manifold 4B and the other connecting body 7B are connected by screwing the threaded parts 4g, 7c of each other, and can be separated by releasing the screwing. Accordingly, the double pipe part formed by the inner pipe 2 and the outer pipe 3 can be easily separated from the respective connecting bodies 7A, 7B and the respective connecting inner pipes 6, 6, and this double pipe part can also be easily separated from the respective manifolds 4A, 4B. Conventionally, it has been difficult to replace a part of the piping structure, but according to this embodiment, a part of the piping structure can be replaced as necessary. For example, damaged or deformed parts can be quickly replaced, improving the maintainability of the piping structure.

[0043] In this embodiment, one manifold 4A is brazed to one tube body 5a before being fitted around the inner tube 2. Also, the other manifold 4B is brazed to the other tube body 5b before being fitted around the inner tube 2. If the manifolds 4A, 4B are brazed to the corresponding tube bodies 5a, 5b before being assembled together with the inner tube 2, the outer tube 3, and the manifolds 4A, 4B as in this embodiment, the assembly process is further simplified.

[0044] It is also possible to install one manifold 4A by clamping it between one connecting body 7A and one longitudinal end of the outer tube 3 to restrict its longitudinal movement, and install the other manifold 4B by clamping it between the other connecting body 7B and the other longitudinal end of the outer tube 3 to restrict its longitudinal movement, and then braze each of the manifolds 4A, 4B to the corresponding tube bodies 5a, 5b. By following this procedure, it is possible to prevent the tube bodies 5a, 5b from getting in the way during the process of assembling the inner tube 2, the outer tube 3, and the manifolds 4A, 4B.

[0045] 13, only an annular seal material S2 for the inner pipe is added to the previous embodiment. That is, the seal material S2 is interposed between the inner pipe 2 and each of the connecting inner pipes 6, 6. As with the seal material S1, various seal materials can be used for this seal material S2.

[0046] In this embodiment, a seal material S2 is disposed on the outer peripheral surface of the connecting inner pipe 6 near the bead portion 6b. Therefore, the gaps between the inner peripheral surfaces of the respective flare portions 2a, 2b and the outer peripheral surfaces of the respective tapered tubular portions 6a facing thereto are complementarily sealed by the respective seal materials S2. According to this embodiment, the inner pipe 2 and each connecting inner pipe 6 are more reliably connected airtightly. In addition, the flow paths of each connecting inner pipe 6 and the flow path of the inner pipe 2, which are in communication with each other, are isolated from the flow path between the outer peripheral surface of the inner pipe 2 and the inner peripheral surface of the outer pipe 3 by the respective seal materials S2. Therefore, it is more advantageous to reliably prevent the low temperature fluid LF and the high temperature fluid HF from mixing. [Explanation of symbols]

[0047] 1 heat exchanger 2 Inner tube 2a, 2b Flare section 3 outer tube 4A, 4B manifold 4c, 4d through hole 4e Tapered through hole 4f Flange part 4g Screw part 5a, 5b Body 6 Connection inner pipe 6a Tapered tube 6b Bead section 7A, 7B Concatenation 7c Threaded part 8 Reamer S1 Annular seal for outer pipe S2 Annular seal for inner pipe P1, P2 flow path P3 interior space LF Cryogenic fluid HF high temperature fluid

Claims

1. The device has an inner pipe and an outer pipe that form a double pipe structure, a cylindrical manifold that is inserted around the inner pipe and installed at both ends of the outer pipe in the longitudinal direction, and a pipe body brazed to each of the manifolds, In a piping structure of a heat exchanger, longitudinal ends of the outer tube are sealed by the manifolds, flow paths of the tube bodies are in communication with internal spaces of the brazed manifolds, and flow paths between an outer circumferential surface of the inner tube and an inner circumferential surface of the outer tube are in communication with an outer circumferential side region of the inner tube in the internal spaces of the manifolds, the manifold includes an annular seal for an outer pipe interposed between each of the manifolds and the outer pipe, one connecting inner pipe connected to one longitudinal end of the inner pipe, the other connecting inner pipe connected to the other longitudinal end of the inner pipe, one cylindrical connecting body inserted onto the one connecting inner pipe, and the other cylindrical connecting body inserted onto the other connecting inner pipe, Flared portions are formed at both longitudinal ends of the inner tube, and longitudinal ends of the connecting inner tubes facing the respective flared portions are formed into tapered tubular portions to be inserted into the flared portions, A threaded portion is formed on an outer peripheral surface of each of the manifolds at a longitudinal end portion, and a tapered through hole extending in the longitudinal direction is formed on an inner peripheral surface of each of the manifolds, the threaded portion of one of the manifolds and the threaded portion of the one of the connecting bodies are screwed together, whereby the tapered tubular portion inserted into the one of the flared portions and the flared portion thereof are pressed from the outer circumferential side by the inner circumferential surface of the tapered through hole of the one of the manifolds, so that the tapered tubular portion, the flared portion and the inner circumferential surface of the tapered through hole are integrated and tightly attached to each other, and the one of the manifolds is sandwiched between the one of the connecting bodies and one longitudinal end of the outer tube, and is installed such that movement in the longitudinal direction is restricted, As a result of the threaded portion of the other manifold and the threaded portion of the other connecting body being screwed together, the tapered cylindrical portion inserted into the flare portion of the other manifold and its flare portion are pressed from the outer circumferential side by the inner circumferential surface of the tapered through hole of the other manifold, so that the tapered cylindrical portion, its flare portion and the inner circumferential surface of the tapered through hole are integrated and tightly attached, and the other manifold is clamped between the other connecting body and the other longitudinal end of the outer tube, thereby restricting its longitudinal movement. This is a piping structure of a heat exchanger.

2. 2. The piping structure of a heat exchanger as described in claim 1, wherein each of the manifolds has a cylindrical flange portion that is inserted into the outer pipe, and an annular seal material for the outer pipe is arranged between the outer peripheral surface of each of the flange portions and the inner peripheral surface of the outer pipe.

3. 3. The piping structure of a heat exchanger according to claim 1, further comprising an annular seal for the inner pipe interposed between the inner pipe and each of the connecting inner pipes.

4. A method for manufacturing a piping structure of a heat exchanger having a double-pipe structure of an inner pipe and an outer pipe, a cylindrical manifold that is inserted around the inner pipe and installed at both longitudinal ends of the outer pipe, and a pipe body brazed to each of the manifolds, comprising: preparing one connecting inner tube to be connected to one longitudinal end of the inner tube, the other connecting inner tube to be connected to the other longitudinal end of the inner tube, one cylindrical coupling body to be inserted onto the one connecting inner tube, and the other cylindrical coupling body to be inserted onto the other connecting inner tube; A threaded portion is formed on an outer peripheral surface of each of the manifolds at a longitudinal end portion, and a tapered through hole is formed on an inner peripheral surface thereof so as to extend in the longitudinal direction, One longitudinal end of each of the connecting inner tubes is formed into a tapered cylindrical portion, one flare portion is formed at one longitudinal end of the inner tube, one of the manifolds is fitted onto the inner tube so that the one flare portion comes into contact with an inner peripheral surface of the tapered through hole of one of the manifolds, the outer tube is fitted onto the inner tube, and then the other manifold is fitted onto the inner tube, and the space between each of the manifolds and the outer tube is sealed with annular sealing materials for the outer tube at a position where the outer tube is sandwiched between the manifolds, and both longitudinal ends of the outer tube are sealed with the manifolds, a second flare portion is formed at the other longitudinal end portion of the inner tube, and the second flare portion is brought into contact with an inner peripheral surface of the tapered through hole of the other manifold, the threaded portion of one of the manifolds is screwed into the threaded portion of the one of the connecting bodies, and the tapered tubular portion and its flared portion of the one of the connecting inner tubes inserted into the one of the flared portions are pressed from the outer circumferential side by the inner circumferential surface of the tapered through hole of the one of the manifolds, so that the tapered tubular portion, the flared portion and the inner circumferential surface of the tapered through hole are integrated and tightly attached to each other, and the one of the manifolds is clamped between the one of the connecting bodies and one longitudinal end of the outer tube to restrict longitudinal movement thereof, and installed; the threaded portion of the other manifold is screwed into the threaded portion of the other connecting body, and the tapered cylindrical portion of the other connecting inner tube inserted into the flared portion of the other connecting inner tube and its flared portion are pressed from the outer circumferential side by the inner circumferential circle of the tapered through hole of the other manifold, so that the tapered cylindrical portion, the flared portion and the inner circumferential surface of the tapered through hole are integrated and tightly attached to each other, and the other manifold is clamped between the other connecting body and the other longitudinal end of the outer tube to restrict longitudinal movement and install it; A manufacturing method for a piping structure of a heat exchanger, which connects a flow path between the outer peripheral surface of the inner tube and the inner peripheral surface of the outer tube with an outer peripheral region of the inner tube in the internal space of one of the manifolds and the other of the manifolds, connects a flow path of one of the tube bodies brazed to one of the manifolds with the internal space of one of the manifolds, and connects a flow path of the other of the tube bodies brazed to the other manifold with the internal space of the other manifold.

5. 5. A method for manufacturing a piping structure of a heat exchanger according to claim 4, wherein one of the manifolds is brazed to one of the pipe bodies before the one of the manifolds is externally fitted onto the inner pipe, and the other of the manifolds is brazed to the other of the pipe bodies before the other of the manifolds is externally fitted onto the inner pipe.

6. 5. A method for manufacturing a piping structure of a heat exchanger as described in claim 4, wherein one of the manifolds is clamped between the one of the connecting bodies and one longitudinal end of the outer pipe to restrict its longitudinal movement and installed, and the other of the manifolds is clamped between the other of the connecting bodies and the other longitudinal end of the outer pipe to restrict its longitudinal movement, and then the one of the manifolds is brazed to the one of the pipe bodies and the other of the manifolds is brazed to the other of the pipe bodies.

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