Heat exchanger and manufacturing method thereof

Abstract

The invention relates to a heat exchanger which comprises a shell, a first tube plate and a second tube plate are arranged in the shell at intervals, the shell is divided into a first cavity, a second cavity and a third cavity by the first tube plate and the second tube plate, a plurality of first heat exchange tubes are arranged in the second cavity, and a first medium flows through the first cavity, the plurality of first heat exchange tubes and the third cavity; the header assembly is arranged in the second cavity and comprises two partition plates, header pipelines are arranged at the two ends of each partition plate respectively, a plurality of second heat exchange pipes are arranged between the two partition plates, the two ends of each second heat exchange pipe communicate with the header pipelines respectively, and the header pipelines and the second heat exchange pipes allow a second medium to flow. The first heat exchange pipes are distributed on the two sides of the header assembly. And a third medium flows in the space outside the first heat exchange tubes and the second heat exchange tubes in the second cavity. Turbulent flow can be formed by utilizing the temperature difference of different media to spontaneously perform heat exchange.

Description

Technical Field

[0001] The invention relates to the technical field of heat exchangers, in particular to a heat exchanger and a manufacturing method thereof. Background Art

[0002] The tubular heat exchanger is a partition-type heat exchanger that uses the wall surface of the tube bundle enclosed in the shell as the heat transfer surface. During use, two media for heat exchange flow inside and outside the tube bundle respectively.

[0003] The patent with the publication number CN117906413A discloses a tubular heat exchanger, including tube heads on both sides, a tube shell in the middle, a tube bundle located inside, and two groups of double tube sheets, wherein the double tube sheets include a first tube sheet and a second tube sheet arranged in parallel. The first tube sheet is arranged on one side close to the tube head; the tube bundle includes a plurality of pipelines, which are arranged inside the tube shell along the length direction of the tube shell, and the two ends of the pipelines pass through a group of double tube sheets correspondingly, and are fixedly connected to the two tube sheets through the extended ends relative to the first tube sheet and the second tube sheet; the tube heads on both sides are respectively surrounded by the two first tube sheets to form a first cavity, and the space inside the two first cavities and the tube bundle is used for the circulation of the first medium; the tube shell in the middle, the space between the two second tube sheets and the outside of the tube bundle are surrounded by a second cavity, and the space inside the second cavity is used for the circulation of the second medium.

[0004] When the above-mentioned tubular heat exchanger is used, additional equipment such as a water pump is required to apply pressure to cause the medium outside the tube bundle to flow for heat exchange, which increases the operating cost of the equipment. In addition, one device can only use one low-temperature medium to cool another high-temperature medium at a time, which is inefficient. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a heat exchanger and a manufacturing method thereof to solve the above-mentioned problems.

[0006] In order to solve the above technical problems, the technical solutions provided by the present invention are as follows:

[0007] A heat exchanger comprising at least:

[0008] A shell, wherein a first tube sheet and a second tube sheet are arranged in the shell at intervals along the length direction of the shell, and the shell is divided into a first cavity, a second cavity and a third cavity which are independent of each other by the first tube sheet and the second tube sheet, wherein the second cavity is located between the first cavity and the third cavity, and a plurality of hollow first heat exchange tubes are arranged in the second cavity, wherein one end of the plurality of first heat exchange tubes is fixedly connected to the first tube sheet and communicated with the first cavity, and the other end of the plurality of first heat exchange tubes is fixedly connected to the second tube sheet and communicated with the third cavity, and the first cavity, the plurality of first heat exchange tubes and the third cavity are for the first medium to flow;

[0009] A header assembly, the header assembly is arranged in the second cavity, and includes two baffles arranged in parallel along the length direction of the shell, the two baffles form an upper opening and a lower opening, both ends of the baffles are respectively provided with header pipes, a plurality of hollow second heat exchange tubes are arranged between the two baffles, both ends of the plurality of second heat exchange tubes are respectively connected with the header pipe, the header pipe and the plurality of second heat exchange tubes are for the second medium to flow, and the plurality of first heat exchange tubes are distributed on both sides of the header assembly;

[0010] The space inside the second cavity and outside the plurality of first heat exchange tubes and the plurality of second heat exchange tubes is for the third medium to flow, the temperature of the second medium is higher than the temperature of the first medium, and the temperature of the first medium is higher than the temperature of the third medium.

[0011] In a preferred embodiment, the partition includes a first partition, a second partition and a third partition arranged along the length direction of the shell, and waist-shaped holes are respectively provided at one end of the first partition, both ends of the second partition and one end of the third partition, the waist-shaped hole of the first partition and the waist-shaped hole at one end of the second partition are connected by bolts, and the waist-shaped hole at the other end of the second partition and the waist-shaped hole of the third partition are connected by bolts.

[0012] In a preferred embodiment, a third tube sheet is provided between the partition and the header pipe, and an end portion of the second heat exchange tube passes through the third tube sheet and is connected to the header pipe.

[0013] In a preferred embodiment, a plurality of dummy tubes are provided on a side of the partition away from the second heat exchange tube.

[0014] In a preferred embodiment, the dummy tube includes a first dummy tube and a second dummy tube which are sleeved with each other, wherein one end of the first dummy tube away from the second dummy tube is fixedly connected to the third tube sheet, and one end of the second dummy tube away from the first dummy tube is fixedly connected to the second partition plate, and the first dummy tube and the second dummy tube can undergo relative displacement along the axial direction.

[0015] In a preferred embodiment, a plurality of support parts are provided at the bottom of the header assembly, and the support parts are provided with four support legs, and the four support legs are arranged in a rectangular shape.

[0016] In a preferred embodiment, a plurality of support rods are arranged between the two partitions, and both ends of the plurality of support rods are respectively fixedly connected to the partitions.

[0017] In a preferred embodiment, at least two support plates are provided in the second cavity, the support plates are formed by welding a plurality of round steels, the support plates are supported and fixed by a plurality of tie rods, and the two ends of the tie rods are fixedly connected to the first tube sheet and the second tube sheet respectively.

[0018] In a preferred embodiment, the shell includes a first tube head and a second tube head located at both ends and a middle tube shell located in the middle, the first tube head is provided with a first inlet connected to the first cavity, the second tube head is provided with a first outlet connected to the third cavity, the middle tube shell is provided with a second inlet connected to one of the header pipes, a second outlet connected to the other header pipe, a third inlet connected to the second cavity, and a third outlet, the shell is placed at an angle, and an observation hole for observation is provided on the shell.

[0019] The present invention also includes a method for manufacturing a heat exchanger, comprising:

[0020] Step A: Place the middle tube shell separately;

[0021] Step B: Place the assembled header assembly into a designated position in the middle tube shell;

[0022] Step C: welding the first tube sheet to a designated position;

[0023] Step D: welding one end of a plurality of tie rods to the first tube sheet;

[0024] Step E: Weld the support plate from the middle tube shell to the other end of the first tube plate through the tie rod and fix it to the corresponding position;

[0025] Step F: Passing a plurality of first heat exchange tubes through the first tube sheet and the support plate in sequence;

[0026] Step G: Place the second tube sheet from the other end of the first tube sheet welded to the middle tube shell into the designated position, and make the other end of the first heat exchange tube pass through the second tube sheet, and then weld the second tube sheet;

[0027] Step H: welding the two ends of the first heat exchange tube to the first tube sheet and the second tube sheet respectively;

[0028] Step I: Install the first tube head and the second tube head at two ends of the middle tube shell.

[0029] Compared with the prior art, the heat exchanger of this embodiment has the following beneficial effects:

[0030] 1) The first medium flows in the first cavity, the first heat exchange tubes, and the third cavity, the second medium flows in the header pipe and the second heat exchange tubes, and the third medium flows in the second cavity, the first heat exchange tubes, and the space outside the second heat exchange tubes. Since the temperature of the second medium is higher than that of the first medium, and the temperature of the first medium is higher than that of the third medium, an upper opening and a lower opening will be formed when the two baffles are arranged in parallel. Due to the temperature difference with other media, the third medium will spontaneously form a circulating turbulent flow from the upper opening to the second cavity on both sides of the header assembly, and then flow back to the inside of the header assembly from the lower opening. The turbulent flow formed when the third medium flows will contact the first heat exchange tube and the second heat exchange tube, thereby heat exchange occurs, and heat exchange with the first medium and the second medium can be performed without applying additional external pressure;

[0031] 2) One heat exchanger can provide flow for three kinds of media. The third medium with lower temperature can exchange heat with the first medium and the second medium with higher temperature at the same time, so as to cool down two high-temperature media at one time, and the working efficiency is higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of a half-section structure of the heat exchanger of this embodiment;

[0033] Figure 2 Schematic diagram of the fracture structure of the heat exchanger header assembly of this embodiment;

[0034] Figure 3 Schematic diagram of the overall structure of the heat exchanger header assembly of this embodiment;

[0035] Figure 4 Schematic diagram of the top view of the heat exchanger header assembly of this embodiment;

[0036] Figure 5 It is a partial structural schematic diagram of the heat exchanger header assembly of this embodiment;

[0037] Figure 6 This is a schematic diagram of the structure of the heat exchanger support portion along the length direction of the shell of this embodiment;

[0038] Figure 7 is a schematic diagram of the cross-sectional structure of the heat exchanger of this embodiment along the length direction of the shell;

[0039] Figure 8 Schematic diagram of the planar structure of the heat exchanger support plate of this embodiment;

[0040] Fig. 9 This is a schematic diagram of the planar structure of the heat exchanger of this embodiment after adding a support plate along the length direction of the shell;

[0041] Fig.10 It is a schematic cross-sectional structural diagram of the connection between the first tube sheet and the first heat exchange tube of the heat exchanger in this embodiment.

[0042] Description of reference numerals: 10-shell, 11-first tube sheet, 12-second tube sheet, 13-first cavity, 14-second cavity, 15-third cavity, 16-first heat exchange tube, 20-header assembly, 21-partition, 22-header pipe, 23-second heat exchange tube, 24-support part, 25-support rod, 26-third tube sheet, 27-first dummy tube, 28-second dummy tube, 29-support plate, 30-pull rod, 101-third A tube head, 102-second tube head, 103-middle tube shell, 104-first inlet, 105-first outlet, 106-second inlet, 107-second outlet, 108-third inlet, 109-third outlet, 110-observation hole, 201-upper opening, 202-lower opening, 211-first partition, 212-second partition, 213-third partition, 214-waist-shaped hole, 241-support foot, A-welding point. DETAILED DESCRIPTION

[0043] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0044] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the mechanism or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0045] like Figure 1 To make the view as clear as possible, Figure 1 The heat exchanger shown in the figure is rotated 90°. Figure 1 The heat exchanger of this embodiment includes an external shell 10, and a first tube sheet 11 and a second tube sheet 12 are arranged in the shell 10 along the length direction of the shell 10. In the figure, only lines are used to represent the first tube sheet 11 and the second tube sheet 12 for clarity, and they actually have thickness.

[0046] The shell 10 is divided into a first cavity 13, a second cavity 14 and a third cavity 15 which are independent of each other by the first tube sheet 11 and the second tube sheet 12. The second cavity 14 is located between the first cavity 13 and the third cavity 15. A plurality of hollow first heat exchange tubes 16 are arranged in the second cavity 14. In order to show the clarity, the first heat exchange tubes 16 are only indicated by lines in the figure, which are actually hollow tubular structures. One end of the plurality of first heat exchange tubes 16 is fixedly connected to the first tube sheet 11 and communicates with the first cavity 13, and the other end is fixedly connected to the second tube sheet 12 and communicates with the third cavity 15. The first cavity 13, the plurality of first heat exchange tubes 16 and the third cavity 15 are for the first medium to flow.

[0047] To facilitate assembly, the shell 10 includes a first tube head 101 and a second tube head 102 located at both ends and a middle tube shell 103 located in the middle. The first tube head 101 is provided with a first inlet 104 connected to the first cavity 13, and the second tube head 102 is provided with a first outlet 105 connected to the third cavity 15.

[0048] A header assembly 20 is disposed in the second cavity 14. Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, the header assembly 20 includes two baffles 21 arranged in parallel along the length direction of the shell 10, the two baffles 21 form an upper opening 201 and a lower opening 202, and header pipes 22 are respectively arranged at both ends of the baffles 21, and a plurality of hollow second heat exchange tubes 23 are arranged between the two baffles 21. In order to show clearly, the second heat exchange tubes 23 are only represented by lines in the figure, which are actually hollow tubular structures.

[0049] like Figure 1 As shown, the middle tube shell 103 is provided with a second inlet 106 connected to one of the header pipes 22 and a second outlet 107 connected to another header pipe 22. Both ends of the plurality of second heat exchange tubes 23 are respectively connected to the header pipe 22, and the header pipe 22 and the plurality of second heat exchange tubes 23 are provided for the second medium to flow. The plurality of first heat exchange tubes 16 are distributed on both sides of the header assembly 20.

[0050] like Figure 1As shown, the middle tube shell 103 is also provided with a third inlet 108 and a third outlet 109 communicated with the second cavity 14, and the space inside the second cavity 14 and outside the plurality of first heat exchange tubes 16 and the plurality of second heat exchange tubes 23 is used for the third medium to flow. The temperature of the second medium is higher than that of the first medium, and the temperature of the first medium is higher than that of the third medium. The third medium flows and contacts with the first heat exchange tubes 16 and the second heat exchange tubes 23, thereby performing heat exchange with the second medium and the first medium, thereby achieving cooling of the second medium and the first medium.

[0051] like Figure 2 As shown, the partition 21 includes a first partition 211, a second partition 212 and a third partition 213 arranged along the length direction of the shell 10. The partition 21 includes a first partition 211, a second partition 212 and a third partition 21 arranged along the length direction of the shell 10. One end of the first partition 211, both ends of the second partition 212 and one end of the third partition 213 are respectively provided with a waist-shaped hole 214, the waist-shaped hole 214 of the first partition 211 and the waist-shaped hole 214 at one end of the second partition 212 are connected by bolts, and the waist-shaped hole 214 at the other end of the second partition 212 and the waist-shaped hole 214 of the third partition 213 are connected by bolts. Since the second heat exchange tube 23 undergoes hot and cold cycles during the heat exchange process, it will produce thermal expansion and contraction, and will produce axial expansion and contraction, so the partition 21 needs to have a corresponding displacement. The partition 21 adopts a three-section structure connected by waist-shaped holes, which can produce corresponding displacement with the thermal expansion and contraction of the second heat exchange tube 23, so that the second heat exchange tube 23 is not easy to break during the heat exchange process.

[0052] like Figure 5 As shown, a third tube sheet 26 is provided between the partition 21 and the header pipe 22, and the end of the second heat exchange tube 23 passes through the third tube sheet 26 and communicates with the header pipe 22. Since the welding requirements between the second heat exchange tube 23 and the header pipe 22 are relatively high, it is impossible to adopt the conventional welding form of small tubes and large tubes, so a third tube sheet 26 with a rectangular plate structure is provided between the partition 21 and the header pipe 22 to facilitate the welding connection between the second heat exchange tube 23 and the header pipe 22.

[0053] like Figure 3 and Figure 5 As shown, a plurality of dummy tubes are arranged on one side of the partition 21 away from the second heat exchange tube 23. Since the distance between the header assembly 20 and the first heat exchange tube 16 is relatively large, a short-circuit phenomenon may occur here, affecting the flow of the third medium, so dummy tubes are arranged to act as heat exchange tubes to avoid the short-circuit phenomenon caused by the large distance.

[0054] The dummy tube includes a first dummy tube 27 and a second dummy tube 28 which are sleeved with each other. The end of the first dummy tube 27 away from the second dummy tube 28 is fixedly connected to the third tube sheet 26, and the end of the second dummy tube 28 away from the first dummy tube 27 is fixedly connected to the second partition 212. Since there is no hot fluid flowing in the dummy tube, the dummy tube and the second heat exchange tube 23 will not be able to expand and contract axially synchronously. When the dummy tube expands and contracts, its welding point will be stressed, and it will tear during use. Therefore, the dummy tube adopts a form of one end being welded and the other end being sleeved. The first dummy tube 27 and the second dummy tube 28 can be relatively displaced in the axial direction, so that the first dummy tube 27 can move with the third tube sheet 26, and the second dummy tube 28 can move with the second partition 212, so as to ensure that the dummy tube can expand and contract accordingly with the displacement of the partition 21, and the dummy tube can also play a supporting role. Of course, the end of the first dummy tube 27 away from the second dummy tube 28 can also be welded to the first partition 211 or the third partition 213, and the same technical effect can be achieved.

[0055] like Figure 3 and Figure 6 As shown, the bottom of the header assembly 20 is provided with a plurality of support parts 24, and the support parts 24 are provided with four support legs 241, and the four support legs 241 are arranged in a rectangular shape. The support parts 24 can suspend the header assembly 20, which is more conducive to the flow of the third medium. At the same time, the design of the four support legs 241 arranged in a rectangular shape can reduce the occupied space and minimize the interference with the flow of the third medium.

[0056] like Figure 4 and Figure 5 As shown, a plurality of support rods 25 are arranged between the two partitions 21, and the two ends of the plurality of support rods 25 are respectively fixedly connected to the partitions 21. The support rods 25 and the partitions 21 are spot welded into one body, which can not only support the second heat exchange tube 23, but also reduce the fluid interference of the second heat exchange tube 23 to the third medium. Moreover, the support rods 25 and the partitions 21 are connected as one body, and can move accordingly with the displacement of the partitions 21, without affecting the expansion and contraction of the second heat exchange tube 23.

[0057] like Figure 7As shown in the cross-sectional view, the first medium flows in the first heat exchange tubes 16 on both sides of the partition 21, the second medium flows in the second heat exchange tubes 23 between the partitions 21, and the third medium flows in the second cavity 14 and in the space outside the plurality of first heat exchange tubes 16 and the plurality of second heat exchange tubes 23. Since the temperature of the second medium is higher than that of the first medium, and the temperature of the first medium is higher than that of the third medium, the third medium will spontaneously form a circulating turbulent flow from the upper opening 201 to the second cavity 14 on both sides of the header assembly 20 under the temperature difference, and then flow back to the inside of the header assembly 20 from the lower opening 202. During the flow process, the third medium contacts the first heat exchange tubes 16 and the second heat exchange tubes 23, thereby performing heat exchange with the second medium and the first medium, thereby achieving cooling of the second medium and the first medium.

[0058] like Figure 1 As shown, at least two support plates 29 are disposed in the second cavity 14. For the sake of clarity, the support plates 29 are only represented by lines, and actually have thickness. Figure 8 As shown, the support plate 29 is formed by welding a number of round steel bars. Fig. 9 As shown, the support plate 29 can not only support the first heat exchange tube 16, but also the hollow structure formed by welding the round steel can minimize the occupied area of ​​the support plate 29 and reduce its interference with the flow of the third medium. It should be noted that the hollow structure formed by welding the round steel is to facilitate the flow of the third medium while supporting it, and of course it can also be welded into other suitable shapes.

[0059] like Figure 1 and Figure 7 As shown, the support plate 29 is supported and fixed by a plurality of tie rods 30, and the two ends of the tie rods 30 are respectively fixedly connected to the first tube sheet 11 and the second tube sheet 12. The tie rods 30 can facilitate the fixing of the support plate 29.

[0060] like Figure 1 As shown, the shell 10 is placed at an angle, and a first inlet 104 for injecting a first medium, a second inlet 106 for injecting a second medium, and a third inlet 108 for injecting a third medium are all arranged at a higher end of the shell 10, so that the flow of different media is more convenient under the action of gravity, so that different media are discharged from their corresponding first outlet 105, second outlet 107, and third outlet 109.

[0061] Since the header assembly 20 is added inside the heat exchanger, the heat exchanger of this embodiment adopts a unique manufacturing method, and the specific steps are as follows:

[0062] Step A: Place the middle tube shell 103 separately;

[0063] Step B: Fix the assembled header assembly 20 at a designated position in the middle tube shell 103;

[0064] Step C: welding the first tube sheet 11 to a designated position;

[0065] Step D: welding one end of a plurality of tie rods 30 to the first tube sheet 11;

[0066] Step E: The support plate 29 is welded from the middle tube shell 103, and the other end of the first tube sheet 11 is passed through the tie rod 30 and fixed to the corresponding position. During this process, the insertion of the tie rod 30 can be observed through the observation hole 110 provided on the shell 10;

[0067] Step F: Passing a plurality of first heat exchange tubes 16 through the first tube sheet 11 and the support plate 29 in sequence;

[0068] Step G: Place the second tube sheet 12 from the other end of the first tube sheet 11 welded to the middle tube shell 103 into the designated position, and make the other end of the first heat exchange tube 16 pass through the second tube sheet 12, and then weld the second tube sheet 12 to the shell 10;

[0069] Step H: Weld the two ends of the first heat exchange tube 16 to the first tube sheet 11 and the second tube sheet 12 respectively. The schematic diagram of the welding structure of the first heat exchange tube 16 and the first tube sheet 11 is shown in FIG. Fig.10 As shown, the welding of the first heat exchange tube 16 and the second tube sheet 12 is also Fig.10 similar;

[0070] Step I: Install the first tube head 101 and the second tube head 102 at two ends of the middle tube shell 103 .

[0071] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

Claims

1. A heat exchanger, characterized in that: At least: A shell (10), wherein a first tube sheet (11) and a second tube sheet (12) are arranged in the shell (10) at intervals along the length direction of the shell (10); the shell (10) is divided into a first cavity (13), a second cavity (14) and a third cavity (15) which are independent of each other by the first tube sheet (11) and the second tube sheet (12); the second cavity (14) is located between the first cavity (13) and the third cavity (15); a plurality of hollow first heat exchange tubes (16) are arranged in the second cavity (14); one end of the plurality of first heat exchange tubes (16) is fixedly connected to the first tube sheet (11) and communicates with the first cavity (13); the other end of the plurality of first heat exchange tubes (16) is fixedly connected to the second tube sheet (12) and communicates with the third cavity (15); the first cavity (13), the plurality of first heat exchange tubes (16) and the third cavity (15) are for a first medium to flow; A header assembly (20), the header assembly (20) being arranged in the second cavity (14), comprising two baffles (21) arranged in parallel along the length direction of the shell (10), the two baffles (21) forming an upper opening (201) and a lower opening (202), a header pipe (22) being respectively arranged at both ends of the baffle (21), a plurality of hollow second heat exchange pipes (23) being arranged between the two baffles (21), the two ends of the plurality of second heat exchange pipes (23) being respectively connected to the header pipe (22), the header pipe (22) and the plurality of second heat exchange pipes (23) being provided with a second medium to flow, and the plurality of first heat exchange pipes (16) being distributed on both sides of the header assembly (20); The space inside the second cavity (14) and outside the plurality of first heat exchange tubes (16) and the plurality of second heat exchange tubes (23) is used for the flow of a third medium, the temperature of the second medium is higher than the temperature of the first medium, and the temperature of the first medium is higher than the temperature of the third medium.

2. The heat exchanger according to claim 1, characterized in that: The partition (21) includes a first partition (211), a second partition (212) and a third partition (213) arranged along the length direction of the shell (10); one end of the first partition (211), both ends of the second partition (212) and one end of the third partition (213) are respectively provided with waist-shaped holes (214); the waist-shaped hole (214) of the first partition (211) and the waist-shaped hole (214) at one end of the second partition (212) are connected by bolts; the waist-shaped hole (214) at the other end of the second partition (212) and the waist-shaped hole (214) of the third partition (213) are connected by bolts.

3. The heat exchanger according to claim 1, characterized in that: A third tube sheet (26) is provided between the partition plate (21) and the header pipe (22), and an end portion of the second heat exchange pipe (23) passes through the third tube sheet (26) and is in communication with the header pipe (22).

4. The heat exchanger according to claim 1, characterized in that: A plurality of dummy tubes are arranged on a side of the partition plate (21) away from the second heat exchange tube (23).

5. The heat exchanger according to claim 4, characterized in that: The dummy tube comprises a first dummy tube (27) and a second dummy tube (28) which are sleeved together. One end of the first dummy tube (27) away from the second dummy tube (28) is fixedly connected to the third tube sheet (26). One end of the second dummy tube (28) away from the first dummy tube (27) is fixedly connected to the second partition plate (212). The first dummy tube (27) and the second dummy tube (28) can be relatively displaced in the axial direction.

6. The heat exchanger according to claim 1, characterized in that: The bottom of the header assembly (20) is provided with a plurality of support parts (24), and the support parts (24) are provided with four support legs (241), and the four support legs (241) are arranged in a rectangular shape.

7. The heat exchanger according to claim 1, characterized in that: A plurality of support rods (25) are arranged between the two partitions (21), and both ends of the plurality of support rods (25) are respectively fixedly connected to the partitions (21).

8. The heat exchanger according to claim 1, characterized in that: At least two support plates (29) are arranged in the second cavity (14). The support plates (29) are formed by welding a plurality of round steels. The support plates (29) are supported and fixed by a plurality of tie rods (30). The two ends of the tie rods (30) are respectively fixedly connected to the first tube sheet (11) and the second tube sheet (12).

9. The heat exchanger according to any one of claims 1 to 8, characterized in that: The shell (10) comprises a first tube head (101) and a second tube head (102) located at two ends and a middle tube shell (103) located in the middle; the first tube head (101) is provided with a first inlet (104) communicating with the first cavity (13); the second tube head (102) is provided with a first outlet (105) communicating with the third cavity (15); the middle tube shell (103) is provided with a second inlet (106) communicating with one of the header pipes (22), a second outlet (107) communicating with the other header pipe (22), a third inlet (108) and a third outlet (109) communicating with the second cavity (14); the shell (10) is placed at an angle; and an observation hole (110) for observation is provided on the shell (10).

10. The method for manufacturing a heat exchanger according to claim 9, characterized in that: include, Step A: placing the middle tube shell (103) separately; Step B: placing the assembled header assembly (20) into a designated position in the middle tube shell (103); Step C: welding the first tube sheet (11) to a designated position; Step D: welding one end of a plurality of tie rods (30) to the first tube sheet (11); Step E: Weld the support plate (29) from the middle tube shell (103) to the other end of the first tube sheet (11), pass it through the tie rod (30) and fix it to the corresponding position; Step F: Passing a plurality of first heat exchange tubes (16) through the first tube sheet (11) and the support plate (29) in sequence; Step G: placing the second tube sheet (12) from the other end of the first tube sheet (11) welded to the middle tube shell (103) into a designated position, and passing the other end of the first heat exchange tube (16) through the second tube sheet (12), and then welding the second tube sheet (12); Step H: welding the two ends of the first heat exchange tube (16) to the first tube sheet (11) and the second tube sheet (12) respectively; Step I: Install the first tube head (101) and the second tube head (102) at both ends of the middle tube shell (103).

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