Plate-fin heat exchanger

Abstract

The application discloses a plate-fin heat exchanger and relates to the technical field of heat exchangers. The plate-fin heat exchanger is sealed by laser welding after vacuum brazing, so that the heat exchanger has high sealing performance with as few sealing elements as possible. Since the sealing elements are reduced, the step of welding the sealing elements to the heat exchanger is omitted, the length of the weld of the heat exchanger in the production process is reduced, and the probability of the air tightness of the heat exchanger being reduced due to weld defects is reduced. The connection between the inlet and outlet of the heat exchanger core and the head is precisely milled to remove surface unevenness, burrs and oxide layers, and the welding quality is improved. The head is arranged on four side walls of the heat exchanger, so that the inlets and outlets of cold and hot fluids are arranged on different side walls, the probability of the cold and hot fluids being mixed and leaked is reduced, and the head is prevented from being welded on the same end face, so that the welding space is not narrow and the welding difficulty is avoided.

Description

Technical Field

[0001] This invention relates to the field of heat exchanger technology, and in particular to a plate-fin heat exchanger. Background Technology

[0002] In solid oxide fuel cell (SOC) systems, plate-fin heat exchangers are the core component for achieving efficient thermal management. They preheat the intake fuel and air by recovering the waste heat from the anode and cathode exhaust gases of the fuel cell stack, which helps to significantly improve the overall energy efficiency of the system. SOC systems typically operate in high-temperature environments (600–850°C), and the severe thermal stress and high-temperature oxidation corrosion place higher demands on the manufacturing process of the heat exchangers. At the same time, the traditional heat exchanger structure limits the manufacturing process to include technical bottlenecks such as difficult brazing, low yield rate, and high cost of precision component processing, which seriously restricts the commercial application of SOC systems. Summary of the Invention

[0003] The main objective of this invention is to propose a plate-fin heat exchanger, which aims to improve the problem of low brazing pass rate in the current heat exchanger manufacturing process, resulting in more defective products and increased manufacturing costs.

[0004] To achieve the above objectives, the present invention proposes a plate-fin heat exchanger, wherein the plate-fin heat exchanger has intersecting X, Y, and Z directions, comprising:

[0005] Heat exchanger core;

[0006] A first heat exchange channel is disposed within the heat exchanger core. The first heat exchange channel has a first inlet and a first outlet. In the X direction, the first inlet and the first outlet are respectively disposed on opposite sides of the heat exchanger core.

[0007] A second heat exchange channel is provided in the heat exchanger core. The second heat exchange channel has a second inlet and a second outlet. In the Y direction, the second inlet and the second outlet are respectively provided on opposite sides of the heat exchanger core.

[0008] In the Z direction, the first heat exchange channel and the second heat exchange channel are arranged in an alternating, stacked manner.

[0009] In one embodiment, the heat exchanger core includes partitions, and the partitions are provided with a plurality of partitions;

[0010] In the Z direction, a plurality of the partitions are stacked sequentially so that the space enclosed between two adjacent partitions forms a first space for accommodating the first heat exchange channel; the partitions have a second space, and the second space is used to accommodate the second heat exchange channel;

[0011] The first inlet and the first outlet are formed on opposite side walls of the two adjacent partitions along the X direction; the second inlet and the second outlet are formed on opposite side walls of the partitions along the Y direction.

[0012] In one embodiment, the partition includes:

[0013] In the Z direction, a first plate has a first cavity and a second cavity respectively on opposite sides; and

[0014] The second plate has a third cavity and a fourth cavity respectively on its opposite sides in the Z direction;

[0015] In the Z direction, the second cavity is arranged facing the third cavity, and the first plate and the second plate are attached to each other so that the second cavity and the third cavity enclose and form the second space, and the adjacent first cavity and the fourth cavity enclose and form the first space.

[0016] In one embodiment, the first heat exchange channel includes a first fin extending along the X direction, and the first inlet and the first outlet are formed at both ends of the first fin along the X direction.

[0017] The second heat exchange channel includes:

[0018] The second fin extends along the X direction; and

[0019] An inlet fin extends along the Y direction; in the X direction, the inlet fin is disposed on one side of the second fin;

[0020] An outlet fin extends along the Y direction; in the X direction, the outlet fin is located on the other side of the second fin;

[0021] In the X direction, the two opposite sides of the second fin are respectively connected to the inlet fin and the outlet fin. The end of the inlet fin away from the end connected to the second fin forms the second inlet, and the end of the outlet fin away from the end connected to the second fin forms the second outlet.

[0022] In one embodiment, in the X direction, the first cavity has a first notch on each side and the fourth cavity has a fourth notch on each side; in the X direction, the first notch and the fourth notch located on the same side and adjacent to each other are joined together to form a first channel for communicating the first inlet or the first outlet with the outside.

[0023] In the Y direction, the second cavity has a second notch on each side and the third cavity has a third notch on each side; in the Y direction, the second notch and the third notch located on the same side and adjacent to each other form a second channel for connecting the second inlet or the second outlet with the outside.

[0024] In one embodiment, the first plate and the second plate are connected by welding, and a weld is formed between the first plate and the second plate;

[0025] The side of the weld away from the first heat exchange channel and the second heat exchange channel is sealed by laser welding.

[0026] In one embodiment, the plate-fin heat exchanger further includes end plates, and the end plates are two in number;

[0027] In the Z direction, the two end plates are respectively disposed on opposite sides of the heat exchanger core, for sealing the side of the partition plate facing the corresponding end plate.

[0028] In one embodiment, the two end plates have a sealing cavity on their opposite sides, and the sealing cavity communicates with the outside on both sides along the X direction;

[0029] The sealing cavity is used to cooperate with the first cavity or the fourth cavity to encapsulate the first fin.

[0030] In one embodiment, the plate-fin heat exchanger further includes:

[0031] A first inlet end cap is connected to one side of the heat exchanger core along the X direction, and the first inlet end cap is used to communicate with the first inlet; and

[0032] A first outlet end cap is connected to the other side of the heat exchanger core along the X direction, and the first outlet end cap is used to communicate with the first outlet.

[0033] The second inlet end cap is connected to one side of the heat exchanger core along the Y direction, and the second inlet end cap is used to communicate with the second inlet;

[0034] The second outlet end cap is connected to the other side of the heat exchanger core along the Y direction, and the second outlet end cap is used to communicate with the second outlet.

[0035] In one embodiment, the surface of the heat exchanger core is milled at the connection between the first inlet end cap, the first outlet end cap, the second inlet end cap, and the second outlet end cap to form a milled surface;

[0036] The first inlet end cap, the first outlet end cap, the second inlet end cap, the second outlet end cap, and the corresponding milled surfaces are connected by welding.

[0037] This invention relates to a plate-fin heat exchanger. After the initial vacuum brazing of the heat exchanger core, laser welding is used to seal the brazed seam. This ensures high sealing performance of the heat exchanger while minimizing the use of sealing components. Furthermore, by reducing the use of sealing components, the step of welding the sealing components to the heat exchanger core is eliminated, significantly reducing the weld length during production and thus lowering the probability of reduced airtightness due to weld defects. Before connecting the end caps to the inlet and outlet of the heat exchanger core, this solution... Precision milling is performed at the connection points of the heat exchanger core inlet, outlet, and end caps to remove surface unevenness, burrs, oxide layers, or other impurities, thereby significantly improving welding quality and further enhancing the sealing performance of the heat exchanger. In this design, the end caps used for fluid inlet and outlet are distributed on the four side walls of the heat exchanger core. This not only distributes the inlet and outlet of hot and cold fluids on different side walls, reducing the probability of cross-leakage between hot and cold fluids, but also avoids the situation where welding the end caps to the same end face results in a narrow welding space and makes welding difficult (increasing welding difficulty). Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of the overall structure of the plate-fin heat exchanger of the present invention;

[0040] Figure 2 This is a schematic diagram of the plate-fin heat exchanger of the present invention in the state of separation between the end cap and the heat exchanger;

[0041] Figure 3 This is a schematic diagram of the core structure of the plate-fin heat exchanger of the present invention;

[0042] Figure 4 This is a schematic diagram showing the separation of the end plate and the heat exchanger core of the plate-fin heat exchanger of the present invention.

[0043] Figure 5 This is an exploded view showing the arrangement of the first plate, the second plate, the first fin, the second fin, the inlet fin, and the outlet fin of the plate-fin heat exchanger of the present invention.

[0044] Figure 6 This is a schematic diagram showing the separation of the first plate and the first fin of the plate-fin heat exchanger of the present invention;

[0045] Figure 7 The plate-fin heat exchanger of the present invention Figure 6 A bottom view of the structure of the first plate component.

[0046] Figure 8 This is a schematic diagram showing the separation of the second plate, inlet fins, and outlet fins of the plate-fin heat exchanger of the present invention.

[0047] Figure 9 The plate-fin heat exchanger of the present invention Figure 8 A bottom view of the second plate component;

[0048] Figure 10 This is a schematic diagram showing the connection relationship of some partition plates in the plate-fin heat exchanger of the present invention;

[0049] Figure 11 This is a schematic diagram showing the positional relationship between the first space and the second space of the plate-fin heat exchanger of the present invention;

[0050] Figure 12 This is a schematic diagram of the edge sealing treatment of the primary brazing seam using the laser welding machine for the plate-fin heat exchanger of the present invention.

[0051] Figure 13 This is a schematic diagram of the precision milling process performed at the connection between the heat exchanger inlet / outlet and the end cap of the plate-fin heat exchanger of the present invention.

[0052] Figure 14 This is a schematic diagram of the manufacturing process of the plate-fin heat exchanger of the present invention.

[0053] Explanation of icon numbers:

[0054] 1. Heat exchanger core; 11. Baffle plate; 111. First plate; 112. Second plate; 12. Milled surface;

[0055] 2. First heat exchange channel; 21. First inlet; 22. First outlet; 23. First fin;

[0056] 3. Second heat exchange channel; 31. Second inlet; 32. Second outlet; 33. Second fin; 34. Inlet fin; 35. Outlet fin;

[0057] 4. Brazing filler metal;

[0058] 5. First space; 51. First cavity; 511. First notch; 52. Second cavity; 521. Second notch;

[0059] 6. Second space; 61. Third cavity; 611. Third notch; 62. Fourth cavity; 621. Fourth notch;

[0060] 7. End plate; 71. Sealing cavity; 8. End cap; 81. First inlet end cap; 82. First outlet end cap; 83. Second inlet end cap; 84. Second outlet end cap;

[0061] 9. Laser welding machine; 10. Milling cutter.

[0062] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0063] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0064] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0065] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0066] In solid oxide fuel cell (SOC) systems, plate-fin heat exchangers are the core component for achieving efficient thermal management. They preheat the intake fuel and air by recovering the waste heat from the anode and cathode exhaust gases of the fuel cell stack, which helps to significantly improve the overall energy efficiency of the system. SOC systems typically operate in high-temperature environments (600–850°C), and the severe thermal stress and high-temperature oxidation corrosion place higher demands on the manufacturing process of the heat exchangers. At the same time, the traditional heat exchanger structure limits the manufacturing process to include technical bottlenecks such as difficult brazing, low yield rate, and high cost of precision component processing, which seriously restricts the commercial application of SOC systems.

[0067] Based on this, refer to Figure 1 , Figure 2 , Figure 6 , Figure 7 As shown, this application provides a plate-fin heat exchanger with intersecting X, Y, and Z directions. The heat exchanger includes a heat exchanger core 1, a first heat exchange channel 2, and a second heat exchange channel 3. The first heat exchange channel 2 and the second heat exchange channel 3 are both located within the heat exchanger core 1. Figure 3 , Figure 4 , Figure 6 As shown, the first heat exchange channel 2 extends along the X direction, and has a first inlet 21 and a first outlet 22 at both ends along the X direction. The first inlet 21 and the first outlet 22 are respectively located on opposite sides of the heat exchanger core 1 along the X direction. The second heat exchange channel 3 is also located inside the heat exchanger core 1, and has a second inlet 31 and a second outlet 32 ​​at both ends along the Y direction. The second inlet 31 and the second outlet 32 ​​are respectively located on opposite sides of the heat exchanger core 1 along the Y direction. It can be understood that the first heat exchange channel 2 in this scheme can be used for the transfer of hot fluid or cold fluid. When the first heat exchange channel 2 is used for the transfer of hot fluid, the second heat exchange channel 3 is used for the transfer of cold fluid. Thus, when the hot and cold fluids move within the first heat exchange channel 2 and the second heat exchange channel 3, they achieve heat exchange, causing the temperature of the hot fluid to decrease and the temperature of the cold fluid to increase, thereby achieving the effect of heat exchange.

[0068] In this embodiment, since the first inlet 21, the second inlet 31, the second outlet 32, and the second outlet 32 ​​are respectively arranged on the four side walls of the heat exchanger core 1, on the one hand, the cold fluid and the hot fluid are distributed on different sides, effectively separating the entry and exit paths of the cold fluid and the hot fluid. This separation can significantly reduce the probability of cross-leakage caused by sealing defects at the inlet / outlet and pipe connection (cross-leakage refers to the mixing of cold and hot fluids inside or outside the heat exchanger, which not only affects heat exchange efficiency but may also lead to equipment damage or safety accidents). On the other hand, distributing the inlet and outlet on the four side walls provides sufficient welding space for welding between the inlet / outlet and the pipe joint. This design makes welding operations more convenient and welding quality easier to guarantee. Sufficient welding space can reduce interference during welding and improve welding accuracy and reliability. For example, welding operators can operate welding equipment more conveniently, thereby reducing welding defects to a certain extent.

[0069] In this embodiment, as Figure 3 As shown, the first heat exchange channel 2 and the second heat exchange channel 3 can be arranged in an alternating layered manner in the Z direction to form a multi-layered structure. This layered structure allows the hot and cold fluids to come into contact multiple times in the vertical direction, thereby increasing the heat exchange area and heat exchange efficiency. This enables heat exchange of multiple hot and cold fluids, thereby improving the heat exchange efficiency.

[0070] Reference Figure 3 , Figure 4 As shown, in one embodiment of this application, the heat exchanger core 1 includes partitions 11, and multiple partitions 11 are provided. In the Z direction, the multiple partitions 11 are stacked sequentially so that the space enclosed between two adjacent partitions 11 forms a first space 5 for accommodating the first heat exchange channel 2. A second space 6 is provided inside the partitions 11, and the second space 6 is used to accommodate the second heat exchange channel 3, such as... Figure 3 , Figure 11 As shown, the first heat exchange channel 2 is located in the first space 5, and the first inlet 21 and the first outlet 22 are respectively formed on the opposite side walls of the two adjacent partitions 11 along the X direction; the second heat exchange channel 3 is located in the second space 6, and the second inlet 31 and the second outlet 32 ​​are formed on the opposite side walls of the partition 11 along the Y direction.

[0071] In this embodiment, multiple partitions 11 are stacked sequentially to provide a carrier for the arrangement of the first heat exchange channel 2 and the second heat exchange channel 3, while allowing the first heat exchange channel 2 and the second heat exchange channel 3 to be arranged alternately at intervals, thereby realizing the heat exchange process of multiple hot and cold fluids; for example, the partitions 11 in this solution can be made of high-temperature resistant and oxidation-resistant metal alloys, such as Inconel 600, SUS310S and GH3030.

[0072] Reference Figure 6 , Figure 7 , Figure 8 , Figure 9 As shown in the figure, in one embodiment of this application, the partition 11 includes a first plate 111 and a second plate 112; wherein, as Figure 6 , Figure 7 As shown, in the Z direction, a first cavity 51 and a second cavity 52 are respectively provided on opposite sides of the first plate 111; as Figure 8 , Figure 9 As shown, in the Z direction, the second plate 112 is adjacent to the third cavity 61 and the fourth cavity 62 on opposite sides; in the Z direction, the second cavity 52 is positioned facing the third cavity 61, and the first plate 111 and the second plate 112 are fitted together (forming a partition 11), thereby allowing the second cavity 52 and the third cavity 61 to enclose and form the second space 6 for accommodating the second heat exchange channel 3; as Figure 3 , Figure 4 , Figure 10 As shown, when multiple partitions 11, which are assembled from the first plate 111 and the second plate 112, are stacked sequentially in the Z direction, the adjacent first cavity 51 and fourth cavity 62 in the Z direction enclose and form a first space 5 for accommodating the first heat exchange channel 2.

[0073] In this embodiment, the connection between two adjacent partitions 11, as well as between the first plate 111 and the second plate 112, can be achieved by welding.

[0074] Reference Figure 6 , Figure 8 As shown, in one embodiment of this application, the first heat exchange channel 2 includes a first fin 23, which extends along the X direction, and a first inlet 21 and a first outlet 22 are formed at both ends of the first fin 23 along the X direction. The first fin 23 is formed by reciprocating bending of a plate to form a structure with multiple channels. When it is placed in the first space 5, the multiple channel structures formed by reciprocating bending are respectively enclosed by the upper and lower walls of the first space 5 to form a channel for guiding fluid flow, so as to realize the transmission of cold fluid or hot fluid.

[0075] In this embodiment, as Figure 8As shown, the second heat exchange channel 3 includes a second fin 33, an inlet fin 34, and an outlet fin 35. The second fin 33 is located between the inlet fin 34 and the outlet fin 35, and extends along the X-direction. The inlet fin 34 and the outlet fin 35 extend along the Y-direction, and are connected to the second fin 33 at both ends along the X-direction. The end of the inlet fin 34 away from the connection with the second fin 33 forms the second inlet 31, and the end of the outlet fin 35 away from the connection with the second fin 33 forms the second outlet. 32; It is understandable that the manufacturing of the second fin 33, the inlet fin 34, and the outlet fin 35 is the same as that of the first fin 23, all of which are formed by repeatedly bending a single sheet to create a structure with multiple channels; In order to enable the inlet fin 34 and the outlet fin 35 to connect with the two ends of the second fin 33 along the X direction, the end of the inlet fin 34 and the outlet fin 35 that connects with the second fin 33 is beveled, thereby allowing one channel on the inlet fin 34 and the outlet fin 35 to connect with multiple channels on the second fin 33; For example Figure 8 As shown, this causes the cold or hot fluid to flow in a Z-shape within the second heat exchange channel 3.

[0076] In this embodiment, as Figure 6 , Figure 8 As shown, the fluid moves in opposite directions within the first fin 23 and the second fin 33, thus achieving counter-current heat transfer. Because the cold and hot fluids flow in opposite directions, the cold fluid remains in contact with the hotter fluid throughout its flow, resulting in more efficient heat transfer. It is understood that the first fin 23 and the second fin 33 are the main heat transfer areas for the cold and hot fluids; therefore, the second fin 33 needs to be made as long as possible along the X-direction to improve the heat transfer efficiency of the cold and hot fluids. Figure 8As shown, the side connecting the inlet fin 34, outlet fin 35, and second fin 33 is obliquely cut (the dimension of the inlet fin 34 gradually decreases along the X direction at the end away from the second inlet 31, and the dimension of the outlet fin 35 gradually decreases along the X direction at the end away from the second outlet 32). While satisfying the requirements for fluid introduction and discharge, this design allows the second fin 33 to have a longer length along the X direction, thereby maximizing the counter-current heat exchange area and improving heat exchange efficiency. However, it is also necessary to ensure sufficient space to accommodate the inlet fin 34 and outlet fin 35 for fluid entry and exit. The fluid moving within the inlet fin 34 and outlet fin 35 can also exchange heat with the fluid moving within the first fin 23. In the above heat exchange method, the first fin 23 and second fin 33 are the main heat exchange areas, while the inlet fin 34 and outlet fin 35 are auxiliary heat exchange areas. This achieves a heat exchange effect where counter-current heat exchange is the primary method and heat exchange through the inlet fin 34 and outlet fin 35 is secondary, while ensuring that the fluid can enter and exit the second fin 33.

[0077] In this embodiment, the second inlet 31 and second outlet 32 ​​of the second heat exchange channel 3 and the first inlet 21 and first outlet 22 of the first heat exchange channel 2 are respectively arranged on four different side walls of the heat exchanger (so that the inlet and outlet of the hot and cold fluids can be separated, and the welding space between the inlet and outlet and the pipe can be increased, effectively reducing the welding difficulty between the inlet and outlet and the pipe); in order to achieve countercurrent heat exchange (a more efficient heat exchange method), inlet fins 34 and outlet fins 35 are arranged along the Y direction to guide the movement trajectory of the fluid and enable the fluid to achieve high-efficiency countercurrent heat exchange with the fluid in the first fin 23 within the second fin 33, thereby improving the heat exchange efficiency of the heat exchanger.

[0078] In this embodiment, the materials of the first fin 23, the second fin 33, the inlet fin 34, and the outlet fin 35 can be high-temperature resistant and oxidation-resistant metal alloys, such as Inconel 600, SUS310S, and GH3030. It is understood that the first fin 23 is welded to the upper and lower walls of the first space 5, and the second fin 33, the inlet fin 34, and the outlet fin 35 are also welded to the upper and lower walls of the second space 6.

[0079] Reference Figure 6 , Figure 8As shown, in one embodiment of this application, in the X direction, the first cavity 51 has a first notch 511 on both sides (so that the first cavity 51 is connected to the outside through the first notch 511 on both sides along the X direction), and the fourth cavity 62 has a fourth notch 621 on both sides (so that the fourth cavity 62 is connected to the outside through the fourth notch 621 on both sides along the X direction); when multiple partitions 11 assembled from the first plate 111 and the second plate 112 are stacked sequentially along the Z direction, the adjacent first notch 511 and fourth notch 621 are combined to form a first channel (e.g., in the Z direction). Figure 3 (As shown), it is used to connect the first inlet 21 and the first outlet 22 to the outside via the first channel, and is also used to connect with the pipe interface; as Figure 7 , Figure 8 As shown, in the Y direction, the second cavity 52 has second notches 521 on both sides (so that the second cavity 52 is connected to the outside through the second notches 521 on both sides along the Y direction), and the third cavity 61 has third notches 611 on both sides (so that the third cavity 61 is connected to the outside through the third notches 611 on both sides along the Y direction). When the first plate 111 and the second plate 112 are assembled to form the partition 11, the second notches 521 and the third notches 611 are assembled to form a second channel, as shown. Figure 3 As shown, this allows the second inlet 31 and the second outlet 32 ​​to be connected to the outside via the second channel and to be used for connection with the pipe interface.

[0080] In this embodiment, as Figure 7 , Figure 8 As shown, the second cavity 52 on the first plate 111 and the third cavity 61 on the second plate 112 are mirror images of each other. This ensures that when the first plate 111 and the second plate 112 are assembled to form the partition 11 structure, the second notch 521 on the first plate 111 corresponds precisely to the third notch 611 on the second plate 112, and they can be assembled to form a second channel (e.g., ...). Figure 11 (As shown).

[0081] It is understandable that, such as Figure 10 As shown, when the first fin 23 is placed in the first space 5, both ends of the first fin 23 along the X direction are located in the first channel (so that the first inlet 21 and the first outlet 22 are flush with both ends of the partition 11 along the X direction); when the inlet fin 34 and the outlet fin 35 are placed in the second space 6, the inlet fin 34 is located away from the end connected to the second fin 33, and the outlet fin 35 is located away from the end connected to the second fin 33 and is located in the second channel (so that the second inlet 31 and the second outlet 32 ​​are flush with both ends of the partition 11 along the Y direction); this arrangement prevents excessive eddies or backflow when the fluid enters and leaves the channel, thereby improving the heat exchange effect.

[0082] Reference Figure 1 , Figure 2 , Figure 3 , Figure 4 As shown, in one embodiment of this application, the plate-fin heat exchanger further includes end plates 7, and there are two end plates 7; in the Z direction, the two end plates 7 are respectively disposed on opposite sides of the heat exchanger core 1, for sealing the side of the partition 11 facing the corresponding end plate 7; since the heat exchanger core 1 in this solution is formed by multiple partitions 11 stacked sequentially, end plates 7 need to be provided at both ends of the heat exchanger core 1 in the Z direction to seal the first fins 23, so that the first fins 23 located at both ends of the heat exchanger core 1 in the Z direction can be in a sealed space (e.g., Figure 3 As shown), it can be understood that by setting the end plate 7 and cooperating with the partition plates 11 located at both ends along the Z direction, a sealed space is provided for the first fins 23 at both ends of the Z direction (equivalent to forming a first heat exchange channel 2); as Figure 4 As shown, it can be understood that in order to achieve the above effect, a sealing cavity 71 is provided on the side of the end plate 7 facing the corresponding partition 11. The structural shape of the sealing cavity 71 should be consistent with the structural shape of the first cavity 51 or the fourth cavity 62, and the sealing cavity 71 is also connected to the outside on both sides along the X direction, thereby achieving the effect of encapsulating the first fin 23.

[0083] In this embodiment, the end plate 7 and the partition plate 11 are connected by welding, and the end plate 7 can be made of a high-temperature resistant and oxidation-resistant metal alloy, such as Inconel 600, SUS310S and GH3030.

[0084] Reference Figure 1 , Figure 2 As shown, in one embodiment of this application, the plate-fin heat exchanger further includes a plurality of end caps 8 for introducing or drawing fluid into or out of the heat exchanger core 1. The end caps 8 include: a first inlet end cap 81, connected to one side of the heat exchanger core 1 along the X direction, and the first inlet end cap 81 is used to communicate with a first inlet 21; a first outlet end cap 82, connected to the other side of the heat exchanger core 1 along the X direction, and the first outlet end cap 82 is used to communicate with a first outlet 22; a second inlet end cap 83, connected to one side of the heat exchanger core 1 along the Y direction, and the second inlet end cap 83 is used to communicate with a second inlet 31; and a second outlet end cap 84, connected to the other side of the heat exchanger core 1 along the Y direction, and the second outlet end cap 84 is used to communicate with a second outlet 32.

[0085] In this embodiment, the first inlet end cap 81 encloses a plurality of first inlets 21 located on one side of the heat exchanger core 1 along the X direction, thereby connecting to an external pipe through the first inlet end cap 81 to deliver fluid to the plurality of first inlets 21; the first outlet end cap 82 encloses a plurality of first outlets 22 located on the other side of the heat exchanger core 1 along the X direction, thereby connecting to an external pipe through the first outlet end cap 82 to discharge fluid flowing out of the plurality of first outlets 22 to the outside through the first outlet end cap 82.

[0086] In this embodiment, the second inlet end cap 83 encloses a plurality of second inlets 31 located on one side of the heat exchanger core 1 along the Y direction, thereby connecting to an external pipe through the second inlet end cap 83 to deliver fluid to the plurality of second inlets 31; the second outlet end cap 84 encloses a plurality of second outlets 32 located on the other side of the heat exchanger core 1 along the Y direction, thereby connecting to an external pipe through the second outlet end cap 84 to discharge fluid flowing out of the plurality of second outlets 32 to the outside through the second outlet end cap 84.

[0087] This application embodiment also provides a method for manufacturing a plate-fin heat exchanger. The plate-fin heat exchanger includes a first plate 111, a second plate 112, a first fin 23, a second fin 33, an inlet fin 34, an outlet fin 35, an end plate 7, and a head 8. The method includes the following steps:

[0088] S1: Assemble the first plate 111, the second plate 112, the first fin 23, the second fin 33, the inlet fin 34, the outlet fin 35, and the end plate 7 according to preset positions to form the heat exchanger core 1, and fix it with brazing clamps; such as Figure 5 As shown, during the assembly process, brazing filler metal 4 needs to be placed on both the upper and lower sides of the first fin 23, the second fin 33, the inlet fin 34, and the outlet fin 35; brazing filler metal 4 also needs to be placed at the contact points between the end plate 7, the first plate 111, and the second plate 112.

[0089] Specifically, during assembly, the brazing fixture is placed on the platform. First, the end plate 7 is placed on the fixture, and then the brazing filler metal 4 and the first fin 23 are placed on the end plate 7 in sequence. The brazing filler metal 4 needs to be placed on both the upper and lower surfaces of the first fin 23 to ensure that the fin can be firmly welded to the plate surface, thereby reducing thermal resistance. Then, the first plate 111, the inlet fin 34, the outlet fin 35, and the second fin 33 are placed in sequence. The brazing filler metal 4 also needs to be placed on both the upper and lower surfaces of the inlet fin 34, the outlet fin 35, and the second fin 33 to ensure that the fin is firmly welded to the plate surface. Then, the second plate 112, the brazing filler metal 4, and the first fin 23 are placed. The above process is repeated until the thickness of the heat exchanger core 1 meets the design requirements. Finally, the end plate 7 is installed and clamped and fixed by the brazing fixture.

[0090] It should be noted that brazing filler metal 4 should be placed at all contact points between two components to ensure a firm weld between the two components.

[0091] S2: Place the assembled heat exchanger core 1 into a vacuum brazing furnace to complete one vacuum brazing operation. For example, the vacuum pressure inside the furnace can be set to 0.005-0.05 Pa, and the core temperature can be raised to 400-500℃ at a heating rate of 3.5-4.5℃ / min, and held for 25-30 minutes. Then, the core temperature can be raised to 850-950℃ at a heating rate of 2-3℃ / min, and held for 15-25 minutes. The core temperature can be raised to 1000-1100℃ at a heating rate of 1.5-2.5℃ / min, and held for 20-30 minutes. Finally, the furnace can be opened when the core temperature drops below 50℃.

[0092] Understandably, when performing this step, due to differences in core material, core size, and solder characteristics, it is necessary to make targeted adjustments to the brazing process parameters.

[0093] S3: As Figure 12 As shown, laser welding machine 9 is used to seal all the primary brazing seams around the heat exchanger core 1, thereby improving the airtightness and structural strength of the primary brazing seams and effectively avoiding the impact of brazing defects on the airtightness of the heat exchanger.

[0094] Traditional heat exchanger structures typically employ sealing strips between adjacent plates to ensure airtightness and pressure resistance, and these sealing strips are welded to the plates. This increases the number of brazed components in the heat exchanger, leading to an increase in the weld length of the heat exchanger core 1. The increased weld length increases the probability of insufficient airtightness and pressure resistance due to weld defects. This solution uses laser welding to seal the primary brazed seam, ensuring the sealing reliability of the heat exchanger core 1 without adding any brazed components.

[0095] Understandably, power needs to be adjusted during laser welding to control the weld penetration (recommended penetration ≤ 1~1.5mm). Laser welding can be used to seal the primary brazed seam by directly melting the base material. The laser beam acts directly on the surface or edge of the primary brazed seam, melting the base material with a high energy density. The laser beam moves along the weld path, causing the molten base material to resolidify, thereby achieving the sealing treatment.

[0096] Alternatively, the welding wire can be placed close to the surface of the primary brazing seam. The laser beam acts on the welding wire, melting it and filling it into the primary brazing seam to form a molten pool. The laser beam moves along the weld seam path, causing the molten welding wire and base material to resolidify, thereby achieving edge sealing.

[0097] S4: After sealing and welding all primary brazing seams, precision mill the connection positions of all inlet and outlet surfaces on the head 8 and heat exchanger core 1 to form milled surfaces 12 (e.g., ...). Figure 13 (As shown); During the precision milling process, the feed rate must be strictly controlled to reduce the impact of cutting force on the weld of heat exchanger core 1. It is recommended that the surface roughness be ≤0.01mm.

[0098] It is understandable that milling cutters 10, in conjunction with corresponding driving components, can be used to perform precision milling on the aforementioned surfaces. Through precision milling, the inlet, outlet, and connection point of the head 8 of the heat exchanger core 1 (i.e., the milled surface 12) can be machined to a very smooth state. This step can remove unevenness, burrs, oxide layers, or other impurities from the original location of the milled surface 12, ensuring the cleanliness and smoothness of the welding surface. A smooth surface facilitates fusion during welding and reduces welding defects caused by surface unevenness, such as porosity, slag inclusions, or lack of fusion. At the same time, a smooth welding surface can reduce the unevenness of heat input during welding, thereby reducing the concentration of welding stress. This allows the milled surface to better fit with the head 8, forming a more uniform and stronger weld, thereby significantly improving the airtightness and pressure resistance of the heat exchanger.

[0099] S5: After precision milling, place brazing filler metal 4 between the inlet, outlet and the corresponding end cap 8, and then use brazing fixtures to clamp and fix the end cap 8 and the heat exchanger core 1.

[0100] S6: Place the assembled heat exchanger core 1 and end cap 8 into a vacuum brazing furnace for secondary vacuum brazing. The brazing process is consistent with the primary vacuum brazing process.

[0101] In this embodiment, the heat exchanger core 1 and the end cap 8 are welded using a secondary brazing process, which can effectively avoid the impact of conventional high-temperature welding on the primary brazing seam of the heat exchanger core 1. Compared with conventional high-temperature welding, laser welding has the advantages of low heat and relatively low temperature, which can further reduce thermal stress and thermal damage, and prevent the primary brazing seam from being remelted.

[0102] S7: After the secondary brazing is completed, the heat exchanger is leak-tested using a pressure-holding fixture to determine whether it meets the usage requirements. The specific pressure and duration of pressure holding are determined according to the design requirements.

[0103] Understandably, before proceeding with S1, material preparation and processing are required; specifically as follows:

[0104] First, according to the size requirements, metal alloy plates are cut on a laser cutting platform to prepare the first plate 111, the second plate 112, and the end plate 7. The laser cutting power and cutting speed need to be adjusted according to the metal type and plate thickness. The metal alloy can be a high-temperature resistant and oxidation-resistant metal alloy, such as Inconel 600, SUS310S and GH3030.

[0105] Secondly, after cutting the aforementioned components, each component needs to be corrected and trimmed. For example, a leveling machine can be used to mechanically level the sheet metal. Since high-temperature alloys generally have high hardness and high elastic modulus, it is recommended to use a multi-roller leveling machine (e.g., 8-12 rolls). Pressure is applied gradually through multiple sets of rollers to reduce damage to the material from excessive pressure in a single application. Simultaneously, the staggered arrangement of the rollers (alternating upper and lower rollers) can evenly distribute stress and improve flatness consistency. During rolling, the roller pressure of the leveling machine should be appropriately increased (higher than that of ordinary stainless steel) to ensure pressure... The high-temperature alloy material is covered to its yield strength to eliminate the original deformation. At the same time, the feeding speed is appropriately reduced (10% to 15% slower than ordinary stainless steel) to extend the action time of the roller on the plate and ensure sufficient correction. It is equipped with a high-precision monitoring system (such as laser or infrared, with an accuracy of ≤0.01mm) to detect the surface undulation deviation of the high-temperature alloy plate in real time. Due to the strong elastic recovery force of the high-temperature alloy, the roller pressure and spacing need to be dynamically adjusted (such as automatically increasing the pressure when the deviation exceeds 0.02mm) to ensure that the flatness of the plate is stable within 0.05 to 0.1mm.

[0106] Then, after the plate is leveled, it needs to be processed on a processing platform into the required channel dimensions of the first plate 111, the second plate 112, and the end plate 7. For example, a low deformation processing method can be used to control the deformation of the plate to be within tolerance, such as CNC machining, EDM, laser processing, or etching. According to the requirements of fin material, fin height, fin spacing, and fin thickness, an automatic fin forming machine is used to process fins into flat, sawtooth, porous, corrugated, needle, or louvered types as required. The processed fins are then processed into inlet fins 34, outlet fins 35, the first fin 23, and the second fin 33 by laser cutting or wire cutting. The first inlet end cap 81, the first outlet end cap 82, the second inlet end cap 83, and the second outlet end cap 84 are made by welding or machining of plate. As needed, brazing sheets or brazing paste can be used as the brazing material 4 required for the heat exchanger in this solution. The brazing sheets can be processed into the required shape and size by laser cutting or other methods.

[0107] Finally, the first plate 111, the second plate 112, the first fin 23, the second fin 33, the inlet fin 34, the outlet fin 35, the end plate 7, and the end cap 8 are placed in an ultrasonic cleaner containing a metal cleaning solution for cleaning; the water temperature is controlled at 55-60℃, and the cleaning time is ≥30 minutes to ensure thorough removal of surface grease, dust, and other contaminants. Finally, they are rinsed thoroughly with clean water and dried. Figure 14 The diagram shown is a schematic of the processing flow of the plate-fin heat exchanger of the present invention.

[0108] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A plate-fin heat exchanger having X-direction, Y-direction and Z-directions which intersect two by two, characterized by, include: A heat exchanger core, comprising a partition, the partition comprising a plurality of staggered and stacked first plates and second plates. In the Z direction, each first plate has a first cavity and a second cavity on opposite sides, and each second plate has a third cavity and a fourth cavity on opposite sides. The second cavities are arranged toward the third cavities, and adjacent first plates and second plates are fitted together to form a first space by adjacent first cavities and fourth cavities, and a second space by adjacent second cavities and third cavities. A first heat exchange channel is disposed within the first space. The first heat exchange channel has a first inlet and a first outlet. In the X direction, the first inlet is formed on one side of the first plate and the second plate, and the first outlet is formed on the other side. as well as A second heat exchange channel is disposed within the second space. The second heat exchange channel has a second inlet and a second outlet. In the Y direction, the second inlet is formed on one side of the first plate and the second plate, and the second outlet is formed on the other side. In the Z direction, the first heat exchange channel and the second heat exchange channel are arranged in an alternating, stacked manner; The sidewalls of the first plate and the second plate are aligned in both the X and Y directions. The first plate and the second plate are connected by welding, and a weld is formed between the first plate and the second plate. The side of the weld away from the first heat exchange channel and the second heat exchange channel is sealed by laser welding.

2. The plate-fin heat exchanger according to claim 1, characterized in that The first heat exchange channel includes a first fin, the first fin extends along the X direction, and the first inlet and the first outlet are formed at both ends of the first fin along the X direction; The second heat exchange channel includes: The second fin extends along the X direction; and An inlet fin extends along the Y direction; in the X direction, the inlet fin is disposed on one side of the second fin; An outlet fin extends along the Y direction; in the X direction, the outlet fin is located on the other side of the second fin; In the X direction, the two opposite sides of the second fin are respectively connected to the inlet fin and the outlet fin. The end of the inlet fin away from the end connected to the second fin forms the second inlet, and the end of the outlet fin away from the end connected to the second fin forms the second outlet.

3. The plate-fin heat exchanger according to claim 1, wherein In the X direction, the first cavity has a first notch on each side and the fourth cavity has a fourth notch on each side; in the X direction, the first notch and the fourth notch located on the same side and adjacent to each other form a first channel for connecting the first inlet or the first outlet with the outside. In the Y direction, the second cavity has a second notch on each side and the third cavity has a third notch on each side; in the Y direction, the second notch and the third notch located on the same side and adjacent to each other form a second channel for connecting the second inlet or the second outlet with the outside.

4. The plate-fin heat exchanger as described in claim 2, characterized in that, The plate-fin heat exchanger also includes end plates, and the end plates are two in number. In the Z direction, the two end plates are respectively disposed on opposite sides of the heat exchanger core, for sealing the side of the partition plate facing the corresponding end plate.

5. The plate-fin heat exchanger as described in claim 4, characterized in that, The two end plates have a sealing cavity on one side facing each other, and the sealing cavity is connected to the outside along both sides of the X direction; The sealing cavity is used to cooperate with the first cavity or the fourth cavity to encapsulate the first fin.

6. The plate-fin heat exchanger as described in any one of claims 1-5, characterized in that, The plate-fin heat exchanger also includes: A first inlet end cap is connected to one side of the heat exchanger core along the X direction, and the first inlet end cap is used to communicate with the first inlet; and A first outlet end cap is connected to the other side of the heat exchanger core along the X direction, and the first outlet end cap is used to communicate with the first outlet. The second inlet end cap is connected to one side of the heat exchanger core along the Y direction, and the second inlet end cap is used to communicate with the second inlet; The second outlet end cap is connected to the other side of the heat exchanger core along the Y direction, and the second outlet end cap is used to communicate with the second outlet.

7. The plate-fin heat exchanger as described in claim 6, characterized in that, The surface of the heat exchanger core is milled at the connection between the first inlet end cap, the first outlet end cap, the second inlet end cap, and the second outlet end cap, forming a milled surface; The first inlet end cap, the first outlet end cap, the second inlet end cap, the second outlet end cap, and the corresponding milled surfaces are connected by welding.

Images