WO2019130386A1

WO2019130386A1 - Method for manufacturing heat exchanger, and heat exchanger

Info

Publication number: WO2019130386A1
Application number: PCT/JP2017/046406
Authority: WO
Inventors: 功介山口; 正章我妻
Original assignee: 三菱電機株式会社
Priority date: 2017-12-25
Filing date: 2017-12-25
Publication date: 2019-07-04
Also published as: JPWO2019130386A1; CN210570100U; JP6861848B2

Abstract

This heat exchanger is provided with an inner tube and an outer tube, in which fluids circulate, respectively. The outer tube is joined to the inner tube in a state of being spirally wound on the outer peripheral surface of the inner tube. The inner tube is configured such that the strength of both end sections on which the outer tube is not wound is higher than the strength of a part on which the outer tube is wound.

Description

Heat exchanger manufacturing method and heat exchanger

The present invention relates to a method of manufacturing a heat exchanger provided with an inner pipe and an outer pipe through which fluid flows, and a heat exchanger.

Some heat exchangers include an inner pipe through which water flows and an outer pipe through which a refrigerant flows. The outer pipe is wound around the outer peripheral surface of the inner pipe. In a heat exchanger having such a structure, the inner pipe and the outer pipe may be heat transfer-joined by brazing or soldering. In the case of heat transfer bonding by brazing or soldering, in addition to the inner and outer tubes, a brazing material used for brazing or a solder used for soldering is required. In addition, a heat source for brazing or soldering must be secured. Therefore, such heat transfer bonding has a problem that the manufacturing cost rises. Therefore, for example, in Patent Document 1, as a method of joining the inner pipe and the outer pipe without using brazing or soldering, the inner pipe and the outer pipe are expanded by expanding the inner pipe with a liquid such as water. A method of intimate contact with the tube is described.

JP 2004-93057 A

In the method of expanding the inner pipe with a liquid such as water as described in Patent Document 1, it is necessary to expand the inner pipe at a very high pressure in order to sufficiently contact the inner pipe and the outer pipe. . However, when high pressure is applied to the inner pipe, the portion of the inner pipe where the outer pipe is not wound is excessively deformed because the strength is weaker than the portion where the outer pipe is not wound. In order to avoid such deformation of the inner pipe, it is conceivable to suppress the pressure applied to the inner pipe. However, if the pressure applied to the inner pipe is insufficient, the adhesion between the inner pipe and the outer pipe becomes weak, and sufficient heat transfer bonding can not be obtained. As a result, there is a problem that a high heat exchange rate can not be obtained between the water flowing through the inner pipe and the refrigerant flowing through the outer pipe.

The present invention has been made to solve the problems as described above, and it is an object of the present invention to provide a method of manufacturing a heat exchanger having a higher heat exchange rate, and a heat exchanger.

A method of manufacturing a heat exchanger according to the present invention includes an inner pipe and an outer pipe through which fluid flows, and the outer pipe is spirally wound around an outer peripheral surface excluding both ends of the inner pipe. A method of manufacturing a heat exchanger joined to the core, wherein the strength of the ends of the inner pipe is made higher than the strength of the portion around which the outer pipe is wound; Expanding the pressure inside the inner pipe, thereby expanding the inner pipe.

A heat exchanger according to the present invention comprises an inner pipe and an outer pipe through which fluid flows, and the outer pipe is joined to the inner pipe in a state of being spirally wound around the outer peripheral surface excluding the both ends of the inner pipe. In the inner pipe, strength of the both ends where the outer pipe is not wound is configured to be higher than strength of a part where the outer pipe is wound.

According to the method of manufacturing a heat exchanger according to the present invention, since the strength of both ends of the inner pipe is made higher than the strength of the portion where the outer pipe is wound, when the inner pipe is expanded, the outer pipe is wound Excessive deformation of both ends of the inner pipe can be suppressed. Therefore, the expansion pressure of the inner pipe can be further increased, and the portion of the inner pipe on which the outer pipe is wound can be brought into close contact with the outer pipe. As a result, a heat exchanger in which the heat exchange efficiency between the inner pipe and the outer pipe is further enhanced is obtained.

It is a figure which shows the heat exchanger which concerns on Embodiment 1 of this invention. It is a figure which expands and shows one end part of the inner tube of the heat exchanger which concerns on Embodiment 1 of this invention. It is a figure which expands and shows the other end part of the inner tube of the heat exchanger which concerns on Embodiment 1 of this invention. It is a flowchart which shows the process of the manufacturing method of the heat exchanger which concerns on Embodiment 1 of this invention. It is a figure which shows the location which anneal-treats in an inner pipe. It is a figure expanding and showing one end of an inner pipe at the time of performing a pipe expansion process. It is a figure which expands and shows the other end part of the inner pipe | tube at the time of performing a pipe expansion process. It is a figure which expands and shows one end part of the inner tube of the heat exchanger which concerns on Embodiment 2 of this invention.

Hereinafter, embodiments of a heat exchanger and a method of manufacturing the same according to the present invention will be described in detail based on the drawings. The present invention is not limited by the embodiments described below. Moreover, in the following drawings, the size and shape of each component may differ from the actual device.

Embodiment 1
FIG. 1 is a view showing a heat exchanger according to Embodiment 1 of the present invention. The heat exchanger 1 has an inner pipe 10, an outer pipe 20A, an outer pipe 20B, and an outer pipe 20C. In the following description, the outer pipe 20A, the outer pipe 20B, and the outer pipe 20C may be collectively referred to as the outer pipe 20. A fluid such as water flows through the inner pipe 10. That is, the inner pipe 10 is, for example, a water pipe. A fluid such as a refrigerant flows through the outer pipe 20A, the outer pipe 20B, and the outer pipe 20C. That is, the outer pipe 20A, the outer pipe 20B, and the outer pipe 20C are, for example, refrigerant pipes. The inner pipe 10 has one end 11, the other end 12, and a helical structure 13. The helical structure 13 is located between the end 11 and the end 12. The inner pipe 10 is bent at a plurality of locations in the helical structure portion 13 and formed in a generally rectangular spiral shape as a whole. A pipe 30 is joined to one end 11 of the both ends of the inner pipe 10, and a pipe 40 is joined to the other end 12.

FIG. 2 is an enlarged view of one end of the inner pipe of the heat exchanger according to Embodiment 1 of the present invention. FIG. 3 is an enlarged view of the other end of the inner pipe of the heat exchanger according to Embodiment 1 of the present invention. 2 and 3 schematically show a cross section of the heat exchanger 1 taken along the axis of the inner pipe 10. As shown in FIG. In FIG. 2, the end 11 of the inner pipe 10 is shown enlarged and in FIG. 3 the end 12 of the inner pipe 10 is shown enlarged. As shown in FIGS. 2 and 3, three helical grooves 13A, a helical groove 13B, and a helical groove 13C are formed on the outer peripheral surface of the helical structure portion 13. The spiral structure of the spiral structure 13 is formed by the ridges 13D between the spiral groove 13A, the spiral groove 13B, and the spiral groove 13C, and the spiral groove 13A, the spiral groove 13B, and the spiral groove 13C, which are valleys. There is. The helical structure of the helical structure portion 13 is obtained by processing a heat transfer tube having a straight tube shape. The helical groove is not formed in the outer peripheral surface of the edge part 11 and the outer peripheral surface of the edge part 12, and the edge part 11 and the edge part 12 have a straight pipe shape. That is, the end 11 and the end 12 respectively constitute a straight pipe portion.

The outer tube 20A is wound around the spiral groove 13A, the outer tube 20B is wound around the spiral groove 13B, and the outer tube 20C is wound around the spiral groove 13C. In a state in which the outer tube 20 is spirally wound around the outer peripheral surface of the inner tube 10, that is, the outer tube 20 is wound around the helical structure 13 and the outer tube 20 is not wound around the end 11 and the end 12 In the state, hydraulic pressure is applied from the inside of the inner pipe 10 as described later. As a result, the inner pipe 10 is expanded in hydraulic pressure, and the outer pipe 20 is joined to the inner pipe 10.

As shown in FIG. 2, a pipe 30 which is a heat transfer pipe is connected to the end portion 11. The inner diameter of the pipe 30 is larger than the outer diameter of the end 11. At one end of the pipe 30, a flared portion 31 whose inner diameter gradually increases outward is formed. The thickness of the pipe 30 is thicker than the thickness of the end 11. The pipe 30 is disposed such that the flare portion 31 faces outward. The other end of the pipe 30 on which the flare portion 31 is not formed is joined to the end 11 of the inner pipe 10 by brazing. The pipe 30 is joined in a state where the inner circumferential surface is in contact with the outer circumferential surface of the end portion 11. Thus, a double structure is formed by the end portion 11 which is a straight pipe portion and the pipe 30.

As shown in FIG. 3, a pipe 40, which is a heat transfer pipe, is connected to the end 12. The inner diameter of the pipe 40 is larger than the outer diameter of the end 12. The thickness of the pipe 40 is thicker than the thickness of the end 12. The end 12 and the pipe 40 are joined by brazing. The pipe 40 is joined in a state where the inner circumferential surface is in contact with the outer circumferential surface of the end 12. Thus, a double structure is formed by the end portion 12 which is a straight pipe portion and the pipe 40.

FIG. 4 is a flowchart showing steps of a method of manufacturing a heat exchanger according to Embodiment 1 of the present invention. In step S1, an annealing process of the inner pipe 10 is performed. As described above, in a state in which the outer pipe 20A, the outer pipe 20B, and the outer pipe 20C are wound around the spiral structure 13 of the inner pipe 10, bending is performed on a plurality of portions of the spiral structure 13 as shown in FIG. As shown in FIG. 2, the heat exchanger 1 is obtained in which the inner pipe 10 is formed into a substantially rectangular spiral shape. Thus, in order to shape the inner pipe 10, in the helical structure portion 13, there is a point where it is bent at an angle of 90 degrees. The helical structure portion 13 is work-hardened because the helical groove 13A, the helical groove 13B, and the helical groove 13C are formed. Therefore, the helical structure 13 has poor processability of bending at an angle of 90 degrees. Then, in order to eliminate the inferiority of the workability of this bending process, annealing is performed to a part of helical structure part 13. FIG.

FIG. 5 is a view showing a portion of the inner pipe 10 to be subjected to the annealing process. The first bending portion X1 indicated by a thick arrow is the processing portion closest to the end portion 11 among the plurality of bending portions to be bent. The second bending portion X2 indicated by a thick arrow is the bending portion closest to the end portion 12 among the plurality of bending portions to be bent. In the annealing step of step S1, the annealing process is not applied to the region Y1 from the end 11 to the front of the first bending portion X1, and from the end 12 to the front of the second bending portion X2. The annealing process is not applied to the area Y2 of. Then, the annealing process is performed on the region Y3 from the first bent portion X1 to the second bent portion X2.

Referring again to FIG. 4, after execution of the annealing step, in step S2, the strength of both ends of the inner pipe 10, that is, the end 11 and the end 12 is determined by the helical structure 13 in which the outer pipe 20 is wound. A reinforcement step is performed to make the strength higher than. In other words, the annealing process described above is performed before the reinforcement process is performed. In the reinforcing step of step S2, as shown in FIG. 2, the pipe 30 is fitted to the end 11 and joined by brazing, and as shown in FIG. 3, the pipe 40 is fitted to the end 12 and brazed It is joined. Here, the strength refers to the pressure resistance when the fluid pressure is applied from the inside of the inner pipe 10. Thereafter, the outer pipe 20A, the outer pipe 20B, and the outer pipe 20C are wound around the helical structure portion 13.

Next, in step S3, an expansion step of expanding the inner pipe 10 around which the outer pipe 20 is wound is performed. FIG. 6 is an enlarged view of one end of the inner pipe when the pipe expansion step is performed. FIG. 7 is an enlarged view of the other end of the inner pipe when the pipe expansion step is performed. 6 and 7 schematically show cross sections of the heat exchanger 1 taken along the axis of the inner pipe 10, as in FIGS. As shown in FIG. 6, the pump 50 is connected to one end 11, and the lid 60 is attached to the other end 12 as shown in FIG. 7. The pump 50 is, for example, a liquid pump. In this state, the pump 50 is operated to raise the pressure in the inner pipe 10 to perform the pipe expansion step of expanding the inner pipe 10, whereby the inner pipe 10 is expanded in hydraulic pressure.

Referring again to FIG. 4, after execution of the pipe expansion step, the process proceeds to step S4, and in the helical structure portion 13, a plurality of bending portions including the first bending portion X1 and the second bending portion X2 of FIG. A bending step is performed to bend the tube 10 to 90 degrees. As a result, the heat exchanger 1 shown in FIG. 1 is obtained.

Then, in the heat exchanger 1 obtained in the above process, the heat flowing between the water flowing through the inner pipe 10 and the refrigerant flowing through the outer pipe 20A, the outer pipe 20B, and the outer pipe 20C exchanges heat. The water flowing through the water, its temperature rises and becomes hot water.

As described above, the helical structure of the helical structure portion 13 is formed by processing a straight tube-shaped heat transfer tube, and the helical structure portion 13 is work-hardened. Furthermore, an outer pipe 20A, an outer pipe 20B, and an outer pipe 20C are wound around the outer peripheral surface of the helical structure portion 13. On the other hand, as shown in FIG. 2, the outer pipe 20 is not wound around the outer peripheral surface of the end portion 11, and the end portion 11 remains as a straight pipe. Similarly, as shown in FIG. 3, the outer pipe 20 is not wound around the outer peripheral surface of the straight pipe portion of the end 12, and the end 12 remains as a straight pipe. Therefore, the strength against the expansion pressure when expanding the inner pipe 10 with a hydraulic pressure is higher in the spiral structure 13 than in the end 11 and the end 12. Therefore, when hydraulic pressure is applied from the inside of the inner pipe 10 in order to ensure sufficient bonding between the inner pipe 10 and the outer pipe 20 in the helical structure 13, the ends 11 and 12 which are straight pipes are excessive. May be transformed into On the other hand, the inner pipe 10 of the first embodiment has a configuration in which the strength of the end 11 and the end 12 is reinforced as described above.

With the above configuration, the strengths of the end portion 11 and the end portion 12 which are portions where the outer tube 20 is not wound are higher than the strengths of the spiral structure portion 13 which is a portion where the outer tube 20 is wound. There is.

According to the first embodiment, a pipe 30 thicker than the end 11 is joined to the end 11, and a pipe 40 thicker than the end 12 is joined to the end 12. And the end 12 is reinforced in strength. Therefore, even when the fluid pressure is applied from the inside of the inner pipe 10, it is possible to suppress the occurrence of excessive deformation due to the fluid pressure. Therefore, when the inner pipe 10 is expanded hydraulically, the expansion pressure can be further increased, and the close contact between the inner pipe 10 and the outer pipe 20 in the spiral structure 13 of the inner pipe 10 can be further enhanced. As a result, the heat exchanger 1 in which the heat exchange efficiency between the inner pipe 10 and the outer pipe 20 is further enhanced is obtained.

In the first embodiment, the end portion 11 is formed by brazing the pipe 30 thicker than the end portion 11 to the end portion 11 and brazing the pipe 40 thicker than the end portion 12 to the end portion 12. And the strength with respect to the hydraulic pressure of the end 12 is increased, but it is not limited thereto. A pipe made of a high strength material may be joined to the end 11 and the end 12. In this case, it is desirable that the quality of the pipe is, for example, a strength of “H” or more according to Japanese Industrial Standards. Also in this case, since the strength of the end 11 and the end 12 is reinforced, the above-described effect can be obtained.

The thickness and materials of the

pipes

30 and 40 are limited to those described above as long as the end 11 and the end 12 can form a double pipe structure having higher strength than the helical structure 13. There is nothing to do.

The annealing process is not applied to the area Y1 and the area Y2 shown in FIG. 5, but is applied to the area Y3. Therefore, the processability when bending the inner pipe 10 and forming it as shown in FIG. 1 can be made better without reducing the strength of the end portion 11 and the end portion 12.

The helical structure portion 13 may be subjected to an annealing treatment without being subjected to the annealing treatment to the

end portions

11 and 12 which are straight pipe portions.

In the first embodiment, the annealing process is performed before the end 11 and the end 12 reinforcement process, but the present invention is not limited to this. For example, the annealing process may be performed after the end 11 and the end 12 are reinforced.

In the first embodiment, the three spiral grooves 13A, the spiral grooves 13B, and the spiral grooves 13C are formed on the outer peripheral surface of the spiral structure 13. However, the number of spiral grooves is not limited to this. A plurality of spiral grooves may be formed in the spiral structure portion 13 and the outer tube may be wound around each spiral groove.

Second Embodiment
FIG. 8 is an enlarged view of one end of an inner pipe of a heat exchanger according to Embodiment 2 of the present invention. The end 101 of the inner pipe 100 is shown in FIG. In FIG. 8, the same members as those in Embodiment 1 are given the same reference numerals. The helical structure portion 103 of the inner tube 100 has the same configuration as the helical structure portion 13 of the inner tube 10 of the first embodiment, and the outer tube 20A, the outer tube 20B, and the outer tube are provided on the outer peripheral surface thereof. 20C is wound. One end 101 of the both ends of the inner pipe 100 is a straight pipe, and is subjected to a contraction process. That is, the outer diameter D1 of the end portion 101 is smaller than the outer diameter D2 of the helical structure portion 103. The end portion 101 is work-hardened by a contraction tube. In addition, the range which performs a pipe contraction process in the edge part 101 is defined so that the pressure loss of the water circuit which the inner pipe | tube 10 forms may not occur, and the intensity | strength of the edge part 101 becomes the highest. The other end of the inner pipe 100 is similarly subjected to a contraction process and is work-hardened. Further, as in the first embodiment, a flared portion for attaching the pump 50 may be formed at the tip of the end portion 101. The other configuration is the same as that of the first embodiment.

The contraction of the end 101 and the other end is performed in the reinforcing step in the first embodiment described above.

According to the second embodiment, the end portion 101 and the other end portion of the inner pipe 100 are work-hardened to reinforce the strength. Therefore, the same effect as that of the first embodiment can be obtained. Furthermore, in the pipe reduction process, the end 101 and the other end are not heated. Therefore, according to the second embodiment, a decrease in strength due to heating can be avoided at the end 101 and the other end.

Reference Signs List 1 heat exchanger, 10 inner pipe, 11 end, 12 end, 13 spiral structure portion, 13A spiral groove, 13B spiral groove, 13C spiral groove, 13D peak portion, 20 outer pipe, 20A outer pipe, 20B outer pipe, 20C Outer pipe, 30 piping, 31 flared part, 40 piping, 50 pump, 60 lid member, 100 inner pipe, 101 end, 103 helical structure part, X1 first bending part, X2 second bending part, Y1 area , Y2 area, Y3 area.

Claims

A method of manufacturing a heat exchanger, comprising: an inner pipe and an outer pipe through which fluid flows, wherein the outer pipe is joined to the inner pipe in a state of being spirally wound around the outer peripheral surface except for both ends of the inner pipe. There,
Strengthening the ends of the inner pipe at a strength higher than the strength of the portion around which the outer pipe is wound;
And b. Expanding the inner tube by raising the pressure in the inner tube around which the outer tube is wound to expand the inner tube.
The method of manufacturing a heat exchanger according to claim 1, wherein the reinforcing step includes the step of fitting and joining a pipe having an inner diameter larger than the outer diameter of the both ends to the both ends.
The method for manufacturing a heat exchanger according to claim 2, wherein the pipe is thicker than the both ends.
The method for manufacturing a heat exchanger according to claim 2, wherein the pipe is configured to have a higher strength than the both ends.
The reinforcing step includes a step of contracting the both ends so that the outer diameter of the both ends in the inner pipe is smaller than the outer diameter of the portion around which the outer pipe is wound. The manufacturing method of the heat exchanger as described in.
The method further includes an annealing step of annealing a portion of the inner pipe before performing the reinforcement step,
The method of manufacturing a heat exchanger according to any one of claims 1 to 5, wherein the annealing step includes the step of annealing the portion around which the outer tube is wound.
The method further includes an annealing step of annealing a portion of the inner pipe before performing the reinforcement step,
The method further includes a bending step of bending a plurality of portions of the inner pipe after the execution of the pipe expansion step to form a spiral.
In the annealing step,
Annealing in a region from one end of the both ends to the front of the first bent portion closest to the one end among the plurality of bent portions to be bent in the bending step There is no treatment.
Annealing in the region from the other end of the two ends to the front of the second bending portion closest to the other end of the plurality of bending portions to be bent in the bending step There is no treatment.
The method for manufacturing a heat exchanger according to any one of claims 1 to 5, wherein the region from the first bending portion to the second bending portion is annealed.
It has an inner pipe and an outer pipe through which fluid flows,
The outer pipe is joined to the inner pipe in a state of being spirally wound around an outer peripheral surface excluding both ends of the inner pipe,
The heat exchanger according to claim 1, wherein in the inner pipe, strengths of the both ends where the outer pipe is not wound are higher than strengths of a part where the outer pipe is wound.
The heat exchanger according to claim 8, wherein a pipe whose inner diameter is larger than the outer diameter of the both ends is joined to the both ends in a state where the inner peripheral surface of the pipe is in contact with the outer peripheral surface of the both ends. .
The heat exchanger according to claim 9, wherein the pipe is thicker than the end portions.
The heat exchanger according to claim 9, wherein the pipe is configured to have a higher strength than the both ends.
The heat exchanger according to claim 8, wherein the outer diameter of each of the end portions is smaller than the outer diameter of a portion around which the outer pipe is wound.
The inner pipe has a helical structure located between the both ends and having a plurality of helical grooves formed on the outer peripheral surface,
The heat exchanger according to any one of claims 8 to 12, wherein the outer tube is wound around the spiral groove.