Diffusion welded plate and tube heat exchanger and method of manufacture

Abstract

The application provides a diffusion-welded plate-tube heat exchanger and a manufacturing method thereof, and the plate-tube heat exchanger comprises an integrated core body, the integrated core body comprises heat exchange plates and pads arranged alternately in sequence, the heat exchange plates are provided with a tube-side medium passage, and the heat exchange plates and the pads are connected integrally in the form of diffusion welding at both ends of the tube-side medium passage, so that the integrated core body forms tube plates at both ends of the tube-side medium passage; the application can completely eliminate the gap between the heat exchange tubes and the tube plates, avoid the welding defects of the sealing welding opening, realize the reliable connection of the heat exchange tubes and the tube plates without expansion joint sealing, compared with the prior art, after the heat exchange plates and the pads are assembled, the integrated core body can be manufactured through one diffusion welding process, the heat exchange tubes and the tube plates do not need to be welded respectively, the production operation difficulty is greatly reduced, the production efficiency is improved, and the risk of gap corrosion of the heat exchange tubes and the tube plates is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heat exchangers, in particular to a diffusion welded plate-tube heat exchanger and a manufacturing method thereof. BACKGROUND

[0002] The most core manufacturing technology of the existing shell-and-tube heat exchanger is the connection between the heat exchange tube and the tube plate. According to the requirements of GB / T151-2014, the connection between the heat exchange tube and the tube plate can be achieved by adopting the scheme of welding + expansion. The welding scheme includes sealing welding and strength welding, and the expansion scheme includes strength expansion and paste expansion. The shell-and-tube heat exchanger is generally manufactured by adopting the method of expansion sealing welding of the heat exchange tube and the tube plate. The gap between the heat exchange tube and the tube plate is eliminated by the expansion method, and the reliable sealing of the end of the heat exchange tube and the tube plate is achieved by sealing welding. However, in the actual operation condition, due to the difference in thickness of the heat exchange tube and the precision deviation of the heat exchange tube hole processing, the actual expansion degree of each heat exchange tube is different, generally between 4-8%. In the actual operation process of the heat exchanger, due to the temperature difference between the heat exchange tube and the tube plate, the gap between the heat exchange tube and the tube plate will change with the change of the operation condition. In the working condition with crevice corrosion such as Cl - Under the existing conditions, crevice corrosion often leads to failure of the heat exchange tube. In the failure of the heat exchanger, the failure caused by the failure of expansion sealing welding accounts for more than 30% of the failure proportion. Such conditions may require heat exchange tubes and tube plates with stronger crevice corrosion resistance. Such materials are often very expensive, greatly increasing the manufacturing cost of the equipment.

[0003] In order to eliminate the gap of expansion as much as possible, the existing technology has developed manufacturing technologies such as inner hole welding. However, the inner hole welding has large operation amount, low production efficiency and great difficulty in non-destructive testing, resulting in high popularization cost. Therefore, for the industrial shell-and-tube heat exchanger, the expansion welding scheme between the heat exchange tube and the tube plate in the existing technology undoubtedly has the problems of difficult complete elimination of the gap between the heat exchange tube and the tube plate, complicated process operation and low production efficiency. SUMMARY

[0004] Therefore, the present application aims to provide a diffusion welded plate-tube heat exchanger and a manufacturing method thereof, which solves the problems of difficult complete elimination of the gap between the heat exchange tube and the tube plate, complicated operation and low production efficiency in the expansion welding scheme between the heat exchange tube and the tube plate in the prior art.

[0005] To achieve the above-mentioned purpose, the technical scheme of the present application is as follows:

[0006] The application discloses a diffusion-welded plate-tube heat exchanger, which comprises an integrated core body, the integrated core body comprises heat exchange plates and pads which are arranged alternately, the heat exchange plates are provided with a tube-side medium channel, and the heat exchange plates and the pads are connected in a diffusion-welded mode at both ends of the tube-side medium channel to form tube plates at both ends of the tube-side medium channel.

[0007] Further, the heat exchange plate is provided with a first end and a second end, one end of the tube-side medium channel extends to the first end, and the other end of the tube-side medium channel extends to the second end, and the pads are arranged between the first ends of any two adjacent heat exchange plates and between the second ends of any two adjacent heat exchange plates.

[0008] Further, the tube-side medium channel penetrates the first end and the second end respectively.

[0009] Further, the heat exchange plate is provided with a plate body extension section at the first end and the second end, so that the tube-side medium channel is located inside the heat exchange plate, and both ends of the tube-side medium channel do not penetrate the heat exchange plate.

[0010] Further, the heat exchange plate comprises an upper plate body and a lower plate body, the upper plate body and the lower plate body are connected in a diffusion-welded mode, a flow channel is arranged on the side of the upper plate body facing the lower plate body, and / or a flow channel is arranged on the side of the lower plate body facing the upper plate body, so that the tube-side medium channel is formed between the upper plate body and the lower plate body.

[0011] Further, for any one heat exchange plate, the upper plate body and the lower plate body are both provided with flow channels, and the end of the flow channel of the upper plate body and the end of the flow channel of the lower plate body are arranged in a mirror-symmetrical mode.

[0012] Further, the plate-tube heat exchanger comprises a shell and two tube boxes, the tube boxes are connected with the tube plates one by one, the tube boxes are communicated with the tube-side medium channels, and the shell at least surrounds the outside of all the heat exchange plates, so that a shell-side medium channel is formed between the inner cavity of the shell and the integrated core body.

[0013] The application further discloses a manufacturing method of the diffusion-welded plate-tube heat exchanger.

[0014] S1, machining flow channels on the upper plate body and / or the lower plate body, and polishing the surfaces of the upper plate body and the lower plate body;

[0015] S2, assembling one heat exchange plate by buckling the upper plate body and the lower plate body together, and forming a tube-side medium channel between the upper plate body and the lower plate body;

[0016] S3, place the assembled heat exchange plate in a vacuum diffusion welding furnace, and connect the upper plate body and the lower plate body into an integrated whole through diffusion welding;

[0017] S4, manufacture a sufficient number of heat exchange plates according to steps S1-S3;

[0018] S5, machine and surface treat each heat exchange plate and the cushion block;

[0019] S6, stack the cushion block and the heat exchange plate in sequence to assemble a core structure;

[0020] S7, place the assembled core structure in a vacuum diffusion welding furnace to perform a second diffusion welding to realize diffusion connection of the heat exchange plate and the cushion block, and obtain the integrated core with a tube sheet;

[0021] S8, connect the tube box with the tube sheet, then perform a tightness test and a pressure test on the tube side, connect the shell with the tube sheet or the tube box after the tube side test is qualified, then perform a tightness test and a pressure test on the shell side, and obtain the plate-tube heat exchanger after the shell side test is qualified.

[0022] Further, for each heat exchange plate obtained through step S3, the tube side medium channel is located inside the heat exchange plate, both ends of the tube side medium channel do not penetrate the heat exchange plate, and the tube side medium channel is in a vacuum state.

[0023] Further, step S7 comprises:

[0024] S71, place the assembled core structure in a vacuum diffusion welding furnace to perform a second diffusion welding to realize diffusion connection of the heat exchange plate and the cushion block, and obtain the integrated core;

[0025] S72, perform overall heat treatment on the integrated core;

[0026] S73, machine the tube sheet of the integrated core to expose the tube side medium channel at both ends of the integrated core.

[0027] Compared with the prior art, the diffusion-welded plate-tube heat exchanger and the manufacturing method thereof have the following advantages:

[0028] The application discloses a diffusion-welded plate-tube type heat exchanger and a manufacturing method thereof. BRIEF DESCRIPTION OF DRAWINGS

[0029] The accompanying drawings, which form a part of the specification, are included to provide a further understanding of the application and are incorporated herein for explanation by referring to the embodiments of the present application. In the drawings:

[0030] Figure 1 An explosion schematic diagram of the heat exchange plate before diffusion welding according to the embodiment of the application;

[0031] Figure 2 An assembly schematic diagram of the integrated core according to the embodiment of the application;

[0032] Figure 3 A schematic diagram of the integrated core after diffusion welding and after cutting off part of the core structure according to the embodiment of the application;

[0033] Figure 4 A schematic diagram of the diffusion-welded plate-tube type heat exchanger according to the embodiment of the application;

[0034] Figure 5 Another schematic diagram of the heat exchange plate in the integrated core before diffusion welding according to the embodiment of the application;

[0035] Figure 6 An assembly schematic diagram of the integrated core and the tube box in Figure 5 the embodiment of the application;

[0036] Figure 7 Another schematic diagram of the diffusion-welded plate-tube type heat exchanger according to the embodiment of the application (part of the shell is cut open so as to show the integrated core inside the shell).

[0037] BRIEF DESCRIPTION OF DRAWINGS

[0038] 1, upper plate body; 2, lower plate body; 3, flow channel; 4, heat exchange plate; 5, cushion block; 6, integrated core body; 7, tube plate; 8, tube box; 9, shell; 10, tube side medium channel; 11, shell side medium channel; 12, first end; 13, second end; 14, plate body extension section. DETAILED DESCRIPTION

[0039] The inventive concepts of the present disclosure will be described below using terms that the person skilled in the art commonly uses to convey the substance of their work to other skilled persons in the art. However, these inventive concepts can be embodied in many different forms, and thus should not be considered limited to the embodiments described herein.

[0040] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0041] The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0042] In order to solve the problems of the existing welding scheme between the heat exchange tube and the tube plate, such as the difficulty in completely eliminating the gap between the heat exchange tube and the tube plate, the complicated operation, the low production efficiency and the like, the present embodiment proposes a diffusion welded plate-tube heat exchanger and a manufacturing method thereof, as shown in the accompanying drawings. Figures 1-7 As shown in the accompanying drawings, the plate-tube heat exchanger comprises an integrated core body 6, the integrated core body 6 comprises heat exchange plates 4 and cushion blocks 5 arranged alternately in sequence, the heat exchange plates 4 have tube side medium channels 10, and the heat exchange plates 4 and the cushion blocks 5 are connected in the form of diffusion welding at both ends of the tube side medium channels 10 to form a whole, so that the integrated core body 6 forms tube plates 7 at both ends of the tube side medium channels 10.

[0043] Thus, the heat exchange plates 4 and the cushion blocks 5 are connected in the form of diffusion welding to form a whole, so that the integrated core body 6 forms tube plates 7 at both ends, avoiding the structure design and the manufacturing method of the existing expansion joint sealing welding heat exchange tube and tube plate, manufacturing the integrated core body 6 which does not need expansion joint sealing welding, and the tube plate 7 of the integrated core body 6 can be directly regarded as the traditional tube plate structure, so as to completely eliminate the gap between the heat exchange tube and the tube plate, avoid the existence of the welding defects of the sealing welding opening, and realize the reliable connection of the expansion joint sealing welding-free heat exchange tube and tube plate. In addition, the integrated core body 6 can be manufactured only after the heat exchange plates 4 and the cushion blocks 5 are assembled and subjected to a diffusion welding process, compared with the prior art, without the need for separate welding between each heat exchange tube and tube plate, greatly reducing the difficulty of production operation, being conducive to improving the production efficiency, and reducing the risk of gap corrosion of the heat exchange tube and the tube plate.

[0044] The present application sets multiple heat exchange plates 4 and multiple pads 5. Since the shape of the heat exchange plate 4 and the tube side medium channel 10 is not limited, in order to facilitate description, the heat exchange plate 4 has a first end 12 and a second end 13, one end of the tube side medium channel 10 extends to the first end 12, and the other end extends to the second end 13. The pads 5 are arranged between the first ends 12 of any two adjacent heat exchange plates 4, and the pads 5 are arranged between the second ends 13 of any two adjacent heat exchange plates 4. By arranging the pads 5 only at the positions of the first end 12 and the second end 13, the space between any two adjacent heat exchange plates 4 is not completely filled with the pads 5, but there is a certain space for the shell side medium to flow and exchange heat. It should be noted that the "end" of the heat exchange plate 4 is not simply the end of the conventional plate body, but is determined in combination with the extension positions of the two ends of the tube side medium channel 10.

[0045] The heat exchange plate 4 includes an upper plate body 1 and a lower plate body 2, the upper plate body 1 and the lower plate body 2 are connected as a whole in the form of diffusion welding, a flow channel 3 is arranged on the side of the upper plate body 1 facing the lower plate body 2, and / or a flow channel 3 is arranged on the side of the lower plate body 2 facing the upper plate body 1, so that the tube side medium channel 10 is formed between the upper plate body 1 and the lower plate body 2. The upper plate body 1 and the lower plate body 2 can both be provided with flow channels 3, or one of the upper plate body 1 or the lower plate body 2 can be in the form of a flat plate without flow channels 3.

[0046] For any one heat exchange plate 4, if the upper plate body 1 and the lower plate body 2 are both provided with flow channels 3, at least the end of the flow channel 3 of the upper plate body 1 and the end of the flow channel 3 of the lower plate body 2 are mirror-symmetrically arranged. The flow channel 3 of the upper plate body 1 and the flow channel 3 of the lower plate body 2 can be in a mirror-symmetric relationship, or can not be in a mirror-symmetric relationship, for example: the flow channel 3 of the upper plate body 1 extends in a straight line, and the flow channel 3 of the lower plate body 2 extends in a curve. This non-mirror-symmetric arrangement only needs to ensure that the end of the flow channel 3 of the upper plate body 1 and the end of the flow channel 3 of the lower plate body 2 are in a mirror-symmetric relationship, and finally can form the feed inlet and discharge outlet at both ends of the tube side medium channel 10.

[0047] For the heat exchange plate 4, the tube side medium channel 10 extends from the first end 12 of the heat exchange plate 4 to the second end 13 of the heat exchange plate 4, and the tube side medium channel 10 respectively penetrates the first end 12 and the second end 13, so that the tube side medium can flow into the tube side medium channel 10 from the tube plate 7 at one end of the integrated core 6, and flow out from the tube plate 7 at the other end of the integrated core 6 along the tube side medium channel 10. For a single upper plate body 1 or lower plate body 2, if the two ends of the upper plate body 1 and the lower plate body 2 also correspond to the first end 12 and the second end 13 respectively, the flow channel 3 also corresponds to extending from the first end 12 to the second end 13, which will not be described here.

[0048] In this application, there are no specific restrictions on the extension form of the tube-side medium channel 10 (which can also be regarded as the flow channel 3), and it can be any form such as straight extension, curved extension, bend extension, U-shaped extension, etc. The bottom surface of the flow channel 3 adopts a rounded rectangle to ensure better heat transfer and flow performance.

[0049] However, considering the actual processing environment, as the preferred solution in this application, as shown in the attached... Figures 1-2 As shown, the heat exchange plate 4 has plate extension sections 14 at both the first end 12 and the second end 13, so that the tube-side medium channel 10 is located inside the heat exchange plate 4, and neither end of the tube-side medium channel 10 penetrates the heat exchange plate 4. For a single upper plate 1 or lower plate 2, since the plate extension sections 14 are provided at both the first end 12 and the second end 13, both ends of the flow channel 3 are closed. That is, the flow channel 3 can be regarded as a groove structure with closed ends on the entire plate. This configuration ensures that the tube-side medium channel 10 formed during the vacuum diffusion welding process of the upper plate 1 and the lower plate 2 is in a vacuum state. During subsequent processing and heat treatment, the tube-side medium channel 10 is protected by vacuum, avoiding the influence of the external processing environment on the inner wall of the tube-side medium channel 10. In this form, after the integrated core 6 is processed, only the end of the tube sheet 7 needs to be cut to remove the plate extension section 14 and the corresponding pad structure, so that the integrated core 6 can expose the inlet and outlet of the tube-side medium channel 10, thus forming the form described above where "the tube-side medium channel 10 extends from the first end 12 of the heat exchange plate 4 to the second end 13 of the heat exchange plate 4, and the tube-side medium channel 10 passes through the first end 12 and the second end 13 respectively".

[0050] It should be noted that in this application, "the heat exchange plate 4 has a tube-side medium channel 10". In the production process, it is preferred that "neither end of the tube-side medium channel 10 penetrates the heat exchange plate 4". It can also be that "the tube-side medium channel 10 penetrates the first end 12 and the second end 13 respectively". However, in actual application, regardless of which of the above two forms, it is necessary to ensure that "the tube-side medium channel 10 penetrates the first end 12 and the second end 13 respectively" to meet the flow of the medium.

[0051] The outer wall of the heat exchange plate 4 and / or the inner wall of the tube-side medium channel 10 are provided with turbulence structures, such as fins, threads, turbulence columns, etc., which on the one hand helps to increase the heat exchange area, and on the other hand helps to improve the turbulence of the medium, thereby comprehensively improving the heat exchange performance.

[0052] The plate-tube heat exchanger comprises a shell 9, two tube boxes 8, the tube boxes 8 are connected with the tube plates 7 one by one, the tube boxes 8 are communicated with the tube-side medium channels 10, the shell 9 at least surrounds the outside of all the heat exchange plates 4, so that the closed shell-side medium channel 11 is formed between the inner cavity of the shell 9 and the integrated core 6, the tube boxes 8 have tube-side medium ports, one of the tube boxes 8 can be provided with a tube-side medium inlet, and the other tube box 8 can be provided with a tube-side medium outlet, and the shell 9 is respectively provided with a shell-side medium inlet and a shell-side medium outlet.

[0053] The integrated core 6 can be as shown in the accompanying drawings, and can also have other shapes, which are determined according to the actual shape requirements of the heat exchange plates 4. Figure 3 、 6 The integrated core 6 can be as shown in the accompanying drawings, and can also have other shapes, which are determined according to the actual shape requirements of the heat exchange plates 4. Figure 4 、 7 The overall shape of the shell 9 can be a cuboid, a square, a cylinder, etc., and should be adapted to the shape of the actual integrated core 6. Considering the convenience of assembling the shell 9, the shell 9 can be an integrated shell structure, or a shell structure assembled by multiple plate bodies.

[0054] The tube boxes 8 and the tube plates 7 can be connected by bolts, welding, etc., the shell 9 is connected with the tube plates 7 or the tube boxes 8, and the connection with one of the tube plates 7 or the tube boxes 8 is determined according to the actual space, component shape requirements. Of course, the integrated core 6, the shell 9 and the tube boxes 8 in the present application can be all connected into a whole by diffusion welding to realize a heat exchanger with all diffusion welding. It should be noted that the diffusion welding in the present application is vacuum diffusion welding, and the equipment, operation and process parameters for vacuum diffusion welding can be used in the prior art, and the present application will not be described in detail.

[0055] Meanwhile, the present application provides a manufacturing method of a diffusion-welded plate-tube heat exchanger, comprising:

[0056] S1: According to the heat exchange capacity and pressure drop of the actual heat exchanger, the structure of the flow channel is designed, the appropriate thickness of the material is selected, and the flow channel area is arranged; the design scheme of straight channel, S-shaped channel, Z-shaped channel, etc. can be used.

[0057] S2: According to the shape of the shell 9, the number of channels of each plate can be designed to be different or the same.

[0058] Wherein, the steps S1, S2 are the selection of the material of the plate body, the shape, the setting position and the setting number of the flow channel on the plate body, which should be selected and determined according to the actual heat exchanger production design requirements, and the present application does not limit them, and the steps S1, S2 are not the technical key points of the present application, and the steps S1, S2 do not affect the main technical scheme of the present application.

[0059] S3: machining the flow channel 3 on the upper plate body 1 and / or the lower plate body 2, polishing the surface of the upper plate body 1 and the surface of the lower plate body 2, and the roughness meets the 8K mirror surface requirement.

[0060] S4: assembling the upper plate body 1 and the lower plate body 2 to realize the assembly of a heat exchange plate 4, and forming a tube-side medium channel 10 between the upper plate body 1 and the lower plate body 2.

[0061] Wherein, preferably, in step S3, after the machining of the flow channel 3, the two ends of the flow channel 3 are closed, that is, for the upper plate body 1 and / or the lower plate body 2 with the machined flow channel 3, the end of the flow channel 3 does not penetrate the end of the plate body structure, and the two ends of the flow channel 3 and the corresponding ends of the plate body structure form a plate body extension segment 14, so that the tube-side medium channel 10 is formed between the assembled heat exchange plates 4, and the tube-side medium channel 10 is closed at both ends, so as to realize the closed structure design at the end of the heat exchange tube, so that the upper plate body 1 and the lower plate body 2 form a vacuum state in the tube-side medium channel 10 during the vacuum diffusion welding process, and the tube-side medium channel 10 is protected by vacuum during subsequent machining, heat treatment and other processes, thereby avoiding the influence of the external machining environment on the inner wall of the tube-side medium channel 10.

[0062] S5: placing the assembled heat exchange plate 4 in a vacuum diffusion welding furnace, and connecting the upper plate body 1 and the lower plate body 2 into a whole by diffusion welding.

[0063] Wherein, preferably, for the closed tube-side medium channel 10, the inside of the tube-side medium channel 10 is in a vacuum state after the vacuum diffusion welding.

[0064] S6: manufacturing a sufficient number of heat exchange plates 4 according to steps S3-S5 according to the production requirements;

[0065] S7: machining and surface treating each heat exchange plate 4 and the cushion block 5 to meet the 8K surface requirement of diffusion welding;

[0066] Wherein, the machining can be conventional operations such as cutting, grinding and shaving, so that the parts meet the shape and structure required for assembly, and the surface treatment can be conventional treatment methods such as polishing.

[0067] S8: stacking the cushion block 5 and the heat exchange plate 4 in sequence to assemble a core structure;

[0068] Wherein, for any two adjacent heat exchange plates 4, the thickness of the gasket 5 is consistent to ensure that the heat exchange space between the two heat exchange plates 4 is similar or consistent.

[0069] S9: Place the assembled core structure in a vacuum diffusion welding furnace to perform a second diffusion welding to realize diffusion connection of the heat exchange plates 4 and the gasket 5, and obtain the integrated core 6 with the tube plate 7;

[0070] Then, if the "tube-side medium passages 10 respectively pass through the first end 12 and the second end 13 of the heat exchange plate 4" produced in steps S3 and S4, the tube box 8 is connected to the tube plate 7 one by one, and then the tube-side is subjected to a tightness test and a pressure test; after the tube-side test is qualified, the shell 9 is connected to the tube plate 7 or the tube box 8, preferably by welding, and then the shell-side is subjected to a tightness test and a pressure test; after the shell-side test is qualified, the final required heat exchanger is obtained. Of course, if conditions permit, the integrated core 6, the shell 9, and the tube box 8 can be all connected into a whole by diffusion welding to realize a diffusion-welded heat exchanger.

[0071] Preferably, considering that the present application suggests the form of "both ends of the tube-side medium passage 10 do not pass through the heat exchange plate 4" produced in steps S3 and S4, the manufacturing method further performs the following steps after obtaining the integrated core 6 in step S9 (or S10-S11 below can be regarded as sub-steps of step S9 after obtaining the integrated core 6):

[0072] S10: Perform overall heat treatment on the integrated core 6;

[0073] Wherein, since the related materials of the integrated core 6 may lose performance after diffusion welding, heat treatment is performed to restore the performance of the materials and improve the corrosion resistance of the materials to realize high-reliability application of the heat exchanger. The heat treatment can adopt conventional heat treatment equipment, operation, and process parameters according to the material requirements of the integrated core 6.

[0074] It should be emphasized that, in the heat treatment process, preferably for the integrated core 6 with the tube-side medium passage 10 having both ends closed, the tube-side medium passage 10 is always kept in a vacuum state during the heat treatment process, so that the tube-side medium passage 10 is protected by vacuum and the influence of the external heat treatment environment on the inner wall of the tube-side medium passage 10 is avoided.

[0075] S11: Machine process the tube plate 7 of the integrated core 6 to expose the tube-side medium passage 10 at both ends of the integrated core 6.

[0076] In the machining process, for the integrated core 6 with the tube-pass medium channel 10 closed at both ends, the two ends of the integrated core 6 are exposed to the tube-pass medium channel 10 by machining; if it is needed to change the partial external shape of the integrated core 6, it can also be processed by machining, such as the square in the attached Figure 2 is machined into the circular shape in the attached Figure 3 , and it can also be seen that the two ends of the integrated core 6 are exposed to the tube-pass medium channel 10.

[0077] Then, after the step S11, the tube box 8 is connected with the tube plate 7 one by one, and then the tube-pass is tested for tightness and pressure; after the tube-pass test is qualified, the shell 9 is connected with the tube plate 7 or the tube box 8, preferably by welding, and then the shell-pass is tested for tightness and pressure; after the shell-pass test is qualified, the final required heat exchanger is obtained.

[0078] The above only describes the preferred embodiments of the present application and is not used to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for manufacturing a diffusion-welded plate-tube heat exchanger, characterized in that, The plate-tube heat exchanger includes an integrated core (6), a tube box (8), and a shell (9). The integrated core (6) includes heat exchange plates (4) and pads (5) arranged alternately in sequence. The heat exchange plates (4) have tube-side medium channels (10). At both ends of the tube-side medium channels (10), the heat exchange plates (4) and the pads (5) are connected as one unit by diffusion welding, so that the integrated core (6) forms tube sheets (7) at both ends of the tube-side medium channels (10). The heat exchange plates (4) include an upper plate (1) and a lower plate (2). The manufacturing method includes: S1. Process flow channels (3) on the upper plate (1) and / or the lower plate (2), and polish the surface of the upper plate (1) and the surface of the lower plate (2); S2. The upper plate (1) and the lower plate (2) are fastened together to realize the assembly of a heat exchange plate (4), and a tube-side medium channel (10) is formed between the upper plate (1) and the lower plate (2); S3. Place the assembled heat exchange plate (4) in a vacuum diffusion welding furnace and connect the upper plate (1) and lower plate (2) into a whole by diffusion welding. S4. Manufacture a sufficient number of heat exchange plates (4) according to steps S1-S3; S5. Machining and surface treatment of each heat exchange plate (4) and pad (5); S6. Stack the pad (5) and heat exchange plate (4) in sequence to assemble them into a core structure; S7. The assembled core structure is placed in a vacuum diffusion welding furnace for a second diffusion welding to achieve diffusion connection between the heat exchange plate (4) and the pad (5) and to obtain the integrated core (6) with tube sheet (7). S8. Connect the tube box (8) to the tube sheet (7), and then conduct a tightness test and a pressure test on the tube side; after the tube side test is qualified, connect the shell (9) to the tube sheet (7) or the tube box (8), and then conduct a tightness test and a pressure test on the shell side; after the shell side test is qualified, the plate-tube heat exchanger is obtained. For each heat exchange plate (4) obtained in step S3, the tube-side medium channel (10) is located inside the heat exchange plate (4), and neither end of the tube-side medium channel (10) penetrates the heat exchange plate (4), and the inside of the tube-side medium channel (10) is in a vacuum state. Step S7 includes: S71. The assembled core structure is placed in a vacuum diffusion welding furnace for a second diffusion welding to achieve diffusion connection between the heat exchange plate (4) and the pad (5) to obtain the integrated core (6). S72. Perform overall heat treatment on the integrated core (6); S73. The tube sheet (7) of the integrated core (6) is machined so that the two ends of the integrated core (6) expose the tube-side medium channel (10).

2. The method for manufacturing a diffusion-welded plate-tube heat exchanger according to claim 1, characterized in that, The heat exchange plate (4) has a first end (12) and a second end (13). One end of the tube-side medium channel (10) extends to the first end (12) and the other end extends to the second end (13). A pad (5) is provided between the first ends (12) of any two adjacent heat exchange plates (4) and between the second ends (13) of any two adjacent heat exchange plates (4).

3. The method for manufacturing a diffusion-welded plate-tube heat exchanger according to claim 2, characterized in that, The tubular medium channel (10) passes through the first end (12) and the second end (13) respectively.

4. The method for manufacturing a diffusion-welded plate-tube heat exchanger according to claim 2, characterized in that, The heat exchange plate (4) is provided with plate extension sections (14) at the first end (12) and the second end (13) so that the tube-side medium channel (10) is located inside the heat exchange plate (4) and neither end of the tube-side medium channel (10) penetrates the heat exchange plate (4).

5. The method for manufacturing a diffusion-welded plate-tube heat exchanger according to claim 1, characterized in that, The upper plate (1) and the lower plate (2) are connected as one unit by diffusion welding. A flow channel (3) is provided on the side of the upper plate (1) facing the lower plate (2), and / or a flow channel (3) is provided on the side of the lower plate (2) facing the upper plate (1), so that a tube-side medium channel (10) is formed between the upper plate (1) and the lower plate (2).

6. The method for manufacturing a diffusion-welded plate-tube heat exchanger according to claim 5, characterized in that, For any heat exchange plate (4), both the upper plate (1) and the lower plate (2) are provided with flow channels (3), and at least the ends of the flow channels (3) of the upper plate (1) and the ends of the flow channels (3) of the lower plate (2) are mirror-symmetrically arranged.

7. The method for manufacturing a diffusion-welded plate-tube heat exchanger according to claim 1, characterized in that, The plate-tube heat exchanger includes a shell (9) and two tube boxes (8). The tube boxes (8) are connected to the tube sheet (7) in a one-to-one correspondence. The tube boxes (8) are connected to the tube-side medium channel (10). The shell (9) surrounds at least the outside of all heat exchange plates (4), so that a shell-side medium channel (11) is formed between the inner cavity of the shell (9) and the integrated core (6).

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