Plate-fin heat exchanger core and manufacturing process

Abstract

The invention relates to a plate-fin heat exchanger core and a manufacturing process. The manufacturing process comprises the following steps of raw material selection, part preparation, cleaning, assembling and brazing. According to the method, the heat exchanger core is brazed through five different stages, the temperature difference between the temperature of the vacuum brazing furnace and the temperature of the heat exchanger core is controlled, the temperature of the heat exchanger core and the temperature of the vacuum brazing furnace are made to be different, and in the fourth stage, eutectic melting can occur in brazing metal, and the magnesium evaporation speed is sharply increased. Magnesium steam penetrates through a cracked oxide film of brazing filler metal, the effect of a getter exists, the magnesium steam is combined with a workpiece, the atmosphere in the furnace, the surface of a core assembly in the furnace, residual water vapor and free oxygen, and the pressure in the furnace is increased due to release of hydrogen, so that a vacuum chamber is in an oxygen-free state. By means of the process, the design pressure of products can be increased, the average brazing time is shortened, the non-deformation rate is increased, the yield is increased, and the brazing qualification rate is greatly increased.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of heat exchange equipment, in particular to a plate-fin heat exchanger core and a manufacturing process. BACKGROUND

[0002] The plate-fin heat exchanger is a whole structure equipment fused by fins, sealing strips, partitions and other components through brazing process. The equipment realizes the mutual exchange of heat of various working media and the mutual conversion of working media in gas phase and liquid phase through diversified fin forms (such as sawtooth type, corrugated type, etc.), and is widely used in air separation, natural gas liquefaction, aerospace and other industrial fields.

[0003] In recent years, the heat exchangers with a pressure of 7.0 MPa have been designed and used in succession in China, which accelerates the localization process of large-scale high-pressure aluminum plate-fin heat exchangers. At present, heat exchangers suitable for high temperature and high pressure are needed for supercritical carbon dioxide systems, pressurized water reactors and high temperature gas cooled reactors, while the heat exchangers for high pressure, especially those with a design pressure greater than 9.5 MPa, are still blank in China.

[0004] Further, the manufacturing process of the existing plate-fin heat exchanger also has defects as follows: (1) In the brazing process, the core is prone to deformation, especially the upper half of the core can be recessed by 8-20 mm from the lower half.

[0005] (2) The inner channel and the outer channel of the core are detached during brazing, which will reduce the pressure-bearing capacity of the inner channel and cause the core to leak due to the detachment of the outer channel.

[0006] (3) The brazing time of the core is relatively long, generally 36-48 hours, and the various components constituting the core are prone to silicon corrosion, resulting in scrap, and the scrap rate of the core reaches 3%. SUMMARY

[0007] In view of the defects of the prior art, the purpose of the present application is to provide a plate-fin heat exchanger core and a manufacturing process to solve one or more problems in the prior art.

[0008] To achieve the above-mentioned purpose, the technical solution of the present application is as follows: A manufacturing process of a plate-fin heat exchanger core includes the following steps: Raw material selection: selecting aluminum alloy material: Part preparation: preparing sealing strips, composite plates, fins, partitions and first and second flow guides according to the aluminum alloy material; Cleaning: degreasing and cleaning the fins and the first and second flow guides; performing deoxidizing cleaning on the sealing strips, composite plates and partitions; Assembly: Assemble the cleaned fins, first guide vanes, second guide vanes, seals, partitions and composite plates through a fixture to form the heat exchanger core; Brazing: Place the heat exchanger core into a vacuum brazing furnace for brazing.

[0009] Furthermore, the deoxidation cleaning comprises the following steps: Primary cleaning: add caustic soda solution with a content of 4% to 6% and a temperature of 35°C to 40°C into hot water at a temperature of 35°C to 50°C; Soak the seals, partitions, and composite panels in hot water with caustic soda solution for 2 min ± 1 min to peel off the oxide layer on the surface of the seals, partitions, and composite panels and remove oil stains; Secondary cleaning: Place the sealing plate, partition plate and composite plate in a nitric acid solution with a content of 5% to 8%; The sealing plate, partition plate and composite plate that have been cleaned twice are rinsed with clean water, and the sealing plate, partition plate and composite plate are placed in an oven for drying, and the temperature of the oven is set to 100° C. to 120° C.

[0010] Furthermore, the assembling comprises the following steps: Assemble the guide vanes, fins, and seals on a fixture to form a heat exchange unit body, place composite plates between adjacent layers of heat exchange unit bodies, and finally assemble through the first and second partitions to form a heat exchanger core body; shaping, inspecting and fixing the heat exchanger core to a fixture plate; Clean the particles and dust on the surface of the fixture plate.

[0011] Furthermore, the brazing comprises the following steps: Place the assembled heat exchanger core into a vacuum brazing furnace; In the initial stage of brazing, the temperature difference between the vacuum brazing furnace and the heat exchanger core is controlled to be 50℃~100℃, and the center temperature of the heat exchanger core is T 中 The temperature of the vacuum brazing furnace is 70℃~100℃, and the temperature T of the vacuum brazing furnace is 220℃~280℃; In the first stage of brazing, the temperature difference between the vacuum brazing furnace and the heat exchanger core is controlled to be 50℃~70℃, and the center temperature of the heat exchanger core is T 中 The temperature of the vacuum brazing furnace is 475℃~490℃, and the temperature T of the vacuum brazing furnace is 450℃~470℃; In the second stage of brazing, the temperature difference between the vacuum brazing furnace and the heat exchanger core is controlled to be 70℃~90℃, and the center temperature of the heat exchanger core is T 中 The temperature of the vacuum brazing furnace is 320℃~335℃, and the temperature T of the vacuum brazing furnace is 570℃~590℃; In the third stage of brazing, the temperature difference Δt between the vacuum brazing furnace and the heat exchanger core is controlled to be 8-10℃, and the center temperature of the heat exchanger core is T 中 555-565℃, and the temperature T of the vacuum brazing furnace is 510-560℃. In the fourth stage of brazing, the temperature difference Δt between the vacuum brazing furnace and the heat exchanger core is controlled to be 12-15℃, and the center temperature of the heat exchanger core is T 中 560-563℃, and the temperature T of the vacuum brazing furnace is 552-578℃. In the fifth stage of brazing, the temperature difference Δt between the vacuum brazing furnace and the heat exchanger core is controlled to be 18-25℃, and the center temperature of the heat exchanger core is T 中 573-583℃, and the temperature T of the vacuum brazing furnace is 595-605℃. The temperature of the vacuum brazing furnace is lowered, and the heat exchanger core is cooled in a vacuum state until the temperature of the heat exchanger core is not higher than 500℃.

[0012] Further, when the vacuum brazing furnace is stopped for more than 72 hours or exposed to the atmosphere for more than 4 hours, the heat exchanger core needs to be baked at a temperature of 750℃ for 3-4 hours before vacuum brazing.

[0013] Further, the nitrogen filling in the vacuum brazing furnace is performed by the following steps: First nitrogen filling: nitrogen is filled into the vacuum brazing furnace to 5000Pa, and vacuum is drawn to 100Pa for 5-10 minutes; Second nitrogen filling: nitrogen is filled into the vacuum brazing furnace to 5000Pa, and vacuum is drawn to 100Pa for 5-10 minutes; Third nitrogen filling: nitrogen is filled into the vacuum brazing furnace to 5000Pa, and vacuum is drawn to 100Pa for 5-10 minutes.

[0014] Correspondingly, the application also provides a heat exchanger core manufactured by the manufacturing process of the plate-fin heat exchanger core, which is characterized in that the core comprises partitions, composite plates and a plurality of heat exchange unit bodies, the composite plates are arranged between adjacent heat exchange unit bodies to form a multi-layer structure, and partitions are arranged at the top and bottom of the multi-layer structure. The heat exchange unit body comprises a fin, which is a plate body with a plurality of bending parts, and a first heat exchange channel is formed between adjacent bending parts; a first flow guide plate, which is a plate body with a plurality of second heat exchange channels, and the second heat exchange channels are arranged in a first direction and communicate with the first heat exchange channel; A second flow guide plate, which is a plate body with a plurality of third heat exchange channels arranged along a second direction and communicated with the second heat exchange channels; A sealing strip assembly, which is formed into a rectangular structure by a first sealing strip and a second sealing strip, so that the fins, the first flow guide plate and the second flow guide plate are enclosed in the rectangular structure.

[0015] Further, the center of each second heat exchange channel forms an angle with the transverse axis of the first flow guide plate, and the angle makes the second heat exchange channel inclined relative to the first flow guide plate.

[0016] Further, a flow guide inlet is formed between the first sealing strip and the second sealing strip along the width direction of the rectangular structure.

[0017] Compared with the prior art, the present application has the following beneficial technical effects The present application brazes the heat exchanger core through five different stages, controls the temperature difference between the vacuum brazing furnace and the heat exchanger core, and makes the heat exchanger core and the vacuum brazing furnace temperature at different temperatures, so that in the third stage, the volatile magnesium molecules migrate to the surface of the heat exchanger core through the solid filler metal, and combine with the magnesium oxide adsorbed on the surface of the heat exchanger core, and the water vapor reacts and releases a mixture of hydrogen and oxygen. Further, in the fourth stage, eutectic melting occurs in the filler metal, and the evaporation rate of magnesium increases sharply. The magnesium vapor passes through the broken oxide film of the filler metal, and has the function of "getter". The magnesium vapor combines with the residual water vapor and free oxygen on the surface of the workpiece, the atmosphere in the furnace and the core assembly in the furnace. The pressure in the furnace increases due to the release of hydrogen, so that the vacuum chamber is in an oxygen-free state. By using this process, the design pressure of the product can be improved, the average brazing time can be reduced, the deformation rate can be increased, the yield can be improved, and the brazing qualification rate can be greatly improved.

[0018] Further, nitrogen is filled into the vacuum brazing furnace before vacuum brazing, which can increase the heat convection heat transfer of the heat exchanger core, effectively reduce the internal and external temperature difference of the heat exchanger core, and improve the brazing rate of the heat exchanger core weld. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 A structure schematic diagram of a plate-fin heat exchanger core and a plate-fin heat exchanger core in a manufacturing process of an embodiment of the present application is shown.

[0020] Figure 2 A partial structure diagram of a plate-fin heat exchanger core and a plate-fin heat exchanger core in a manufacturing process of an embodiment of the present application is shown.

[0021] Figure 3A cross-sectional structure schematic diagram of a fin in a plate-fin heat exchanger core body and manufacturing process of an embodiment of the present application is shown.

[0022] Figure 4 A structure schematic diagram of a first flow guide plate in a plate-fin heat exchanger core body and manufacturing process of an embodiment of the present application is shown.

[0023] Figure 5 A structure schematic diagram of a second flow guide plate in a plate-fin heat exchanger core body and manufacturing process of an embodiment of the present application is shown.

[0024] In the drawings, 1 is a partition plate; 2 is a composite plate; 3 is a fin; 300 is a first heat exchange channel; 301 is a bending part; 40 is a first flow guide plate; 400 is a second heat exchange channel; 401 is a first inclined surface; 41 is a second flow guide plate; 410 is a third heat exchange channel; 411 is a second inclined surface; 500 is a first sealing strip; and 501 is a second sealing strip. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the present application more clear, a plate-fin heat exchanger core body and manufacturing process of the present application are further described in detail below in combination with the drawings and specific embodiments. The advantages and features of the present application will be more clear according to the following description. It should be noted that the drawings are very simplified and all use non-precise proportions, only to facilitate, clearly assist the purpose of describing the embodiments of the present application. In order to make the purpose, features and advantages of the present application more obvious and easy to understand, please refer to the drawings. It should be understood that the structure, proportion, size and the like shown in the drawings of the present specification are only used to cooperate with the content disclosed in the specification, so that those skilled in the art can understand and read, and are not used to limit the conditions of the implementation of the present application, so they do not have the technical essence, any modification of the structure, change of the proportion relationship or adjustment of the size, without affecting the effect and purpose that can be achieved by the present application, should still fall within the scope of the technical content disclosed by the present application.

[0026] A manufacturing process of a plate-fin heat exchanger core body, comprising the following steps: S1: raw material selection, selecting aluminum alloy material, in the present embodiment, the aluminum alloy material is preferably 3003 aluminum foil.

[0027] S2: part preparation: according to the aluminum alloy material, a sealing strip, a composite plate, a fin, a partition plate and a first flow guide plate and a second flow guide plate are prepared, wherein the fin is punched by a fin forming machine, and the composite plate, the partition plate, the first flow guide plate and the second flow guide plate are respectively processed and formed according to the specified specifications of the pattern.

[0028] S3: cleaning: degreasing cleaning of the fin and the first flow guide plate and the second flow guide plate; deoxidizing cleaning of the sealing strip, the partition plate and the composite plate; The cleaning includes the following steps: S300: primary cleaning: adding a 4%-6% content caustic solution at 35-40°C into hot water at 35-50°C, and controlling the time for 3-5 minutes, so that the oxide layer and oil stains on the fins, first flow guide, and second flow guide can be removed by primary cleaning.

[0029] The seal, baffle, and composite plate are soaked in the hot water with caustic solution for 2 minutes ± 1 minute to strip the oxide layer on the surface of the seal, baffle, and composite plate and remove the oil stains; Secondary cleaning: placing the seal, baffle, and composite plate into a 5%-8% content nitric acid solution, which is used to neutralize the caustic effect.

[0030] The seal, baffle, and composite plate after secondary cleaning are washed with clean water, and the seal, baffle, and composite plate are placed into an oven for drying, and the temperature of the oven is set to 100-120°C.

[0031] S4 assembly: the fins, first flow guide, second flow guide, seal, baffle, and composite plate after cleaning are assembled into a heat exchanger core through a clamp; The assembly includes the following steps: S400: the first flow guide, second flow guide, fin, seal are assembled into a heat exchange unit on the clamp, the composite plate is arranged between adjacent layers of heat exchange units, and finally the heat exchanger core is assembled through the first baffle and second baffle; S401: the heat exchanger core is shaped, inspected, and fixed on the clamp disc; S402: the particles and dust on the surface of the clamp disc are removed.

[0032] S5: brazing: the heat exchanger core is placed into a vacuum brazing furnace for brazing.

[0033] S500: the assembled heat exchanger core is placed into a vacuum brazing furnace; before vacuum brazing, when the vacuum brazing furnace is stopped for ≥72 hours or exposed to the atmosphere for ≥4 hours, the heat exchanger core needs to be baked at a temperature of 750°C for 3-4 hours before vacuum brazing, which can be used to purify the vacuum brazing furnace.

[0034] S501: the temperature difference Δt between the vacuum brazing furnace and the heat exchanger core is controlled to be 50-100°C in the initial stage of brazing, the center temperature of the heat exchanger core is T 中 70-100°C, and the temperature T of the vacuum brazing furnace is 220-280°C. S502: In the first stage of brazing control, the temperature difference Δt between the vacuum brazing furnace and the heat exchanger core is controlled to be 50-70℃, and the center temperature of the heat exchanger core is T 中 475-490℃, and the vacuum brazing furnace temperature T is 450-470℃.

[0035] S503: In the second stage of brazing control, the temperature difference Δt between the vacuum brazing furnace and the heat exchanger core is controlled to be 70-90℃, and the center temperature of the heat exchanger core is T 中 320-335℃, and the vacuum brazing furnace temperature T is 570-590℃. S504: In the third stage of brazing control, the temperature difference Δt between the vacuum brazing furnace and the heat exchanger core is controlled to be 8-10℃, and the center temperature of the heat exchanger core is T 中 555-565℃, and the vacuum brazing furnace temperature T is 570-590℃; when the heat exchanger core passes through 555-560℃, the volatile magnesium molecules migrate to the surface of the heat exchanger core through the solid filler metal, and combine with the adsorbed magnesium oxide on the surface of the heat exchanger core, and the water vapor reacts and releases a mixture of hydrogen and oxygen.

[0036] S505: In the fourth stage of brazing control, the temperature difference Δt between the vacuum brazing furnace and the heat exchanger core is controlled to be 12-15℃, and the center temperature of the heat exchanger core is T 中 560-563℃, and the vacuum brazing furnace temperature T is 552-578℃; in this stage, eutectic melting occurs in the filler metal, and the evaporation rate of magnesium increases sharply. The magnesium vapor passes through the broken oxide film of the filler metal, and has the function of "getter", and the magnesium vapor combines with the residual water vapor and free oxygen on the surface of the workpiece, the atmosphere in the furnace, and the core assembly in the furnace, and the pressure in the furnace increases due to the release of hydrogen. After this period, the reaction gradually decreases, the remaining contaminants are eliminated, and the magnesium vapor is also depleted. The pressure in the vacuum brazing furnace gradually decreases to a new level, which should reach (2×10-3Pa). At this time, the vacuum brazing furnace continues to work to prevent the increase of the contrast gas load, and at this moment of circulation, the workpiece and the vacuum brazing furnace are in an oxygen-free state, and the magnesium oxide powder will adhere to the inner surface of the furnace body. The magnesium vapor that does not participate in the reaction has a tendency to move away from the hot surface, the surface of the core assembly and the heating element, and condense in the form of magnesium metal on the cold surface.

[0037] S506: In the fifth stage of brazing control, the temperature difference Δt between the vacuum brazing furnace and the heat exchanger core is controlled to be 18-25℃, and the center temperature of the heat exchanger core is T 中The temperature of the vacuum brazing furnace is 595-605 DEG C; when the temperature of the furnace body is 560-590 DEG C, the eutectic melting occurs, the temperature of the filler metal and the base material is different due to different thermal expansion coefficients, and the oxidation film layer on the surface of the aluminum is broken. When the alloy filler metal starts to flow, the fragments of the aluminum oxidation film are swallowed by the molten filler metal. When the filler metal is completely melted, it has a clean and non-oxidized surface. The filler metal flows under the action of capillary force, and the crack is filled and lubricated by the filler metal. When this phenomenon occurs, the heat transfer inside the brazed heat exchanger core is improved, and the phase transition point temperature (573 DEG C) of the center of the uniform temperature assembly of the brazing temperature is stabilized in a very short time, about 5-10 min, to complete the vacuum brazing of the core assembly.

[0038] S507: Reduce the temperature of the vacuum brazing furnace, and cool the heat exchanger core in a vacuum state. When the temperature of the heat exchanger core is not greater than 500 DEG C, the furnace is discharged.

[0039] The following steps are used to fill nitrogen in the vacuum brazing furnace: First nitrogen filling: nitrogen is filled into the vacuum brazing furnace to 5000 Pa, and vacuumed to 100 Pa for 5-10 min.

[0040] Second nitrogen filling: nitrogen is filled into the vacuum brazing furnace to 5000 Pa, and vacuumed to 100 Pa for 5-10 min.

[0041] Third nitrogen filling: nitrogen is filled into the vacuum brazing furnace to 5000 Pa, and vacuumed to 100 Pa for 5-10 min.

[0042] By filling nitrogen in the vacuum brazing furnace, the heat convection heat transfer mode is added to the heat exchanger core of the plate-fin heat exchanger, and the internal and external temperature difference of the heat exchanger core is reduced.

[0043] Correspondingly, the application also provides a heat exchanger core manufactured by the above plate-fin heat exchanger core manufacturing process, and specific reference can be made to Figure 1 The core includes a partition plate 1, a composite plate 2 and a plurality of heat exchange unit bodies, the composite plate 2 is arranged between adjacent unit bodies to form a multi-layer structure, and the partition plate 1 is arranged at the top and bottom of the multi-layer structure.

[0044] Specific reference can be made to Figure 1 The specific structure of the heat exchange unit body is described in detail as follows: The fin 3 is a plate body with a plurality of bending parts 301, the bending parts 301 are continuously bent in a square wave type, and the first heat exchange channel 300 is formed between adjacent bending parts 301.

[0045] The first flow guide plate 40 is a plate body with a plurality of second heat exchange channels 400, and is arranged on the left and right sides of the fin 3. The second heat exchange channels 400 are arranged along a first direction and are in communication with the first heat exchange channels 300. Specifically, please refer to Figure 2 The first direction is an inclined direction, and specifically, the center axis of the second heat exchange channel 400 and the transverse axis of the first flow guide plate 40 form an angle α, and the angle α is in the range of 45-60°. The angle α makes the second heat exchange channel 400 inclined relative to the first flow guide plate 40. The first flow guide plate 40 is used to uniformly distribute the incoming fluid into each first heat exchange channel 300 of the fin 3, and due to the inclined arrangement, the pressure loss of the fluid inflow is minimized.

[0046] Further, please refer to Figure 4 A first inclined surface 401 is further arranged on the first flow guide plate 40, which is used to abut the side surface of the second flow guide plate 41, thereby realizing the abutting communication of the heat exchange channels.

[0047] Please continue to refer to Figure 5 The plate-fin heat exchanger core further comprises a second flow guide plate 41, which is a plate body with a plurality of third heat exchange channels 410. The third heat exchange channels 410 are arranged along a second direction and are in communication with the second heat exchange channels 400. The second flow guide plate 41 has a second inclined surface 411 on one side, which is used to abut the first inclined surface 401. Specifically, in this embodiment, the second direction is a horizontal direction, which is the same as the flow direction of the first heat exchange channels 300 in the fin 3.

[0048] Please continue to refer to Figure 1 And Figure 2 The plate-fin heat exchanger core further comprises a seal assembly, which is formed into a rectangular structure by two first seals 500 and two second seals 501, so that the fin 3, the first flow guide plate 40 and the second flow guide plate 41 are enclosed in the rectangular structure.

[0049] Further, please refer to Figure 2The flow guide inlet is formed between the first sealing strip 500 and the second sealing strip 501 along the width direction of the rectangular structure, and the width of the flow guide inlet is A1-b, wherein b represents the width of the first sealing strip 500, and A1 represents the total width of the flow guide inlet and the first sealing strip 500. By setting the flow guide inlet, the flow rate of the fluid flowing into the third heat exchange channel 410 is lower than the flow rate of the fluid entering the second heat exchange channel 400. The width of the flow guide inlet cannot be set too long, otherwise the size of the heat exchanger core will increase, the metal consumption will increase, and the cost will rise. The width of the flow guide inlet cannot be set too short, otherwise the local resistance loss will increase. Through the above calculation, it can be determined that the fluid has a certain value when bending from the third heat exchange channel 410 into the second heat exchange channel 400.

[0050] At present, the process technical effects of the plate-fin heat exchanger core manufactured by the above manufacturing process and the plate-fin heat exchanger core designed by the traditional process are shown in Table 1: Table 1:

[0051] As can be seen from the above Table 1, the design pressure of the product is significantly improved compared with the original process, and the brazing time is greatly shortened by using the process, the deformation rate of the heat exchange core is greatly reduced, and the product yield is effectively improved.

[0052] The technical features of the above-described embodiments can be combined arbitrarily, and in order to make the description simple, all possible combinations of the technical features in the above-described embodiments are not described, however, as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present application.

[0053] The above-described embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as limiting the scope of the patent. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the protection scope of the present application patent should be subject to the appended claims.

Claims

1. A manufacturing process for a plate-fin heat exchanger core, characterized in that The steps are as follows: Raw material selection: Select aluminum alloy material: Parts preparation: preparing seals, composite plates, fins, partitions, first guide vanes and second guide vanes respectively according to the aluminum alloy materials; Cleaning: Degreasing and cleaning the fins and the first and second guide vanes; performing deoxidation cleaning on the seals, composite plates, and partitions; Assembly: Assemble the cleaned fins, first guide vanes, second guide vanes, seals, partitions and composite plates through a fixture to form the heat exchanger core; Brazing: Place the heat exchanger core into a vacuum brazing furnace for brazing.

2. The manufacturing process of a plate-fin heat exchanger core according to claim 1, characterized in that: The deoxidation cleaning comprises the following steps: Primary cleaning: add caustic soda solution with a content of 4% to 6% and a temperature of 35°C to 40°C into hot water at a temperature of 35°C to 50°C; Soak the seals, partitions, and composite panels in hot water with caustic soda solution for 2 min ± 1 min to peel off the oxide layer on the surface of the seals, partitions, and composite panels and remove oil stains; Secondary cleaning: Place the sealing plate, partition plate and composite plate in a nitric acid solution with a content of 5% to 8%; The sealing plate, partition plate and composite plate that have been cleaned twice are rinsed with clean water, and the sealing plate, partition plate and composite plate are placed in an oven for drying, and the temperature of the oven is set to 100° C. to 120° C.

3. The manufacturing process of a plate-fin heat exchanger core according to claim 1, characterized in that: The assembly comprises the following steps: Assemble the guide vanes, fins, and seals on a fixture to form a heat exchange unit body, place composite plates between adjacent layers of heat exchange unit bodies, and finally assemble through the first and second partitions to form a heat exchanger core body; shaping, inspecting and fixing the heat exchanger core to a fixture plate; Clean the particles and dust on the surface of the fixture plate.

4. The manufacturing process of a plate-fin heat exchanger core according to claim 1, characterized in that: The brazing process comprises the following steps: Place the assembled heat exchanger core into a vacuum brazing furnace; In the initial stage of brazing, the temperature difference between the vacuum brazing furnace and the heat exchanger core is controlled to be 50℃~100℃, and the center temperature of the heat exchanger core is T 中 The temperature of the vacuum brazing furnace is 70℃~100℃, and the temperature T of the vacuum brazing furnace is 220℃~280℃; In the first stage of brazing, the temperature difference between the vacuum brazing furnace and the heat exchanger core is controlled to be 50℃~70℃, and the center temperature of the heat exchanger core is T 中 The temperature of the vacuum brazing furnace is 475℃~490℃, and the temperature T of the vacuum brazing furnace is 450℃~470℃; In the second stage of brazing, the temperature difference between the vacuum brazing furnace and the heat exchanger core is controlled to be 70℃~90℃, and the center temperature of the heat exchanger core is T 中 The temperature of the vacuum brazing furnace is 320℃~335℃, and the temperature T of the vacuum brazing furnace is 570℃~590℃; In the third stage of brazing, the temperature difference between the vacuum brazing furnace and the heat exchanger core is controlled to be 8℃~10℃, and the center temperature of the heat exchanger core is T 中 The temperature of the vacuum brazing furnace is 555℃~565℃, and the temperature T of the vacuum brazing furnace is 510℃~560℃; In the fourth stage of brazing, the temperature difference between the vacuum brazing furnace and the heat exchanger core is controlled to be 12℃~15℃, and the center temperature of the heat exchanger core is T 中 The temperature of the vacuum brazing furnace is 560℃~563℃, and the temperature T of the vacuum brazing furnace is 552℃~578℃; In the fifth stage of brazing, the temperature difference between the vacuum brazing furnace and the heat exchanger core is controlled to be 18℃~25℃, and the center temperature of the heat exchanger core is T 中 The temperature of the vacuum brazing furnace is 573℃~583℃, and the temperature T of the vacuum brazing furnace is 595℃~605℃; Lower the temperature of the vacuum brazing furnace to allow the heat exchanger core to cool under vacuum. Remove the heat exchanger core from the furnace when the temperature is no more than 500°C.

5. The manufacturing process of a plate-fin heat exchanger core according to claim 4, characterized in that: During vacuum brazing, when the vacuum brazing furnace is shut down for ≥72h or exposed to the atmosphere for ≥4h, the heat exchanger core needs to be baked at 750°C and kept warm for 3h to 4h before vacuum brazing.

6. The manufacturing process of a plate-fin heat exchanger core according to claim 1, characterized in that: The following steps are used to fill the vacuum brazing furnace with nitrogen: First nitrogen filling: fill the vacuum brazing furnace with 5000Pa of nitrogen and evacuate to 100Pa for 5-10 minutes; Second nitrogen filling: fill the vacuum brazing furnace with 5000Pa of nitrogen and evacuate to 100Pa for 5-10 minutes; The third nitrogen filling: fill the vacuum brazing furnace with 5000Pa of nitrogen, maintain the vacuum to 100Pa for 5min to 10min.

7. A heat exchanger core manufactured using the plate-fin heat exchanger core manufacturing process according to any one of claims 1 to 6, characterized in that: The core body includes a partition plate, a composite plate and a plurality of heat exchange units, the composite plates are arranged between adjacent heat exchange units to form a multi-layer structure, and partition plates are respectively arranged on the top and bottom of the multi-layer structure; The heat exchange unit comprises The fin is a plate body having a plurality of bent portions, and a first heat exchange channel is formed between adjacent bent portions; a first guide plate, wherein the first guide plate is a plate body having a plurality of second heat exchange channels, wherein the second heat exchange channels are arranged along a first direction and communicate with the first heat exchange channels; a second guide plate, the second guide plate being a plate body having a plurality of third heat exchange channels, the third heat exchange channels being arranged along a second direction and communicating with the second heat exchange channels; The sealing strip assembly is formed by a first sealing strip and a second sealing strip to form a rectangular structure, so that the fins, the first guide plate and the second guide plate are enclosed in the rectangular structure.

8. The heat exchanger core manufactured by the plate-fin heat exchanger core manufacturing process according to claim 7, characterized in that: The center of each second heat exchange channel forms an angle with the horizontal axis of the first guide plate, and the angle causes the second heat exchange channel to be inclined relative to the first guide plate.

9. The heat exchanger core manufactured by the plate-fin heat exchanger core manufacturing process according to claim 7, characterized in that: A flow guide inlet is formed between the first sealing strip and the second sealing strip along the width direction of the rectangular structure.

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