Heat exchange structure high-efficiency brazing constant pressure loading device and constant pressure loading method

Abstract

The present application relates to heat exchange structure high-efficiency brazing constant pressure loading device and constant pressure loading method, the device is composed of insulating layer with through hole, disc spring constant pressure interlayer plate and rigid fastening tool, the upper and lower two groups of combination structure with disc spring are placed between multilayer heat exchange structure and rigid fastening tool as constant pressure interlayer plate, the through hole for installing heating electrode is reserved on the fastening tool and constant pressure interlayer plate, the pressure control is carried out to constant pressure interlayer plate through pressure regulating screw, and the heating rate of different regions is controlled through electrode current.The present application develops special constant pressure clamping device for large-size complex heat exchanger through point array type resistance electrode rapid heating and radiation heating double heat source welding, solves the problems of core body and panel deformation control difficulty in brazing process of plate-fin heat exchanger, and local performance difference caused by inconsistent internal and external heating, and the problems of easy defect and the like, and is especially suitable for large plate-fin heat exchanger product with higher requirements on product performance and reliability.

Description

Technical Field

[0001] This invention relates to a high-efficiency brazing constant pressure loading device and constant pressure loading method for heat exchange structures, belonging to the field of welding technology. Background Technology

[0002] Heat exchangers are core components of the power and environmental control systems of high-end equipment. In recent years, my country's aerospace, naval, and other high-end equipment have seen an urgent demand for the manufacture of high-efficiency plate-fin heat exchangers. Plate-fin radiators mainly consist of panels, fins, and seals. Fins and seals are placed between adjacent panels to form a sandwich layer, which is then stacked according to different fluid directions and brazed into a single unit, constituting the core component of the plate-fin heat exchanger. Plate-fin heat exchangers are large in size and weight. During the brazing process, the strength of the base material decreases at high temperatures, easily causing core deformation, especially severe deformation of the seals and panels. Once deformation occurs, it is difficult to correct effectively. Therefore, in the development of brazing technology for plate-fin heat exchangers, it is necessary to solve the deformation control problem and design suitable tooling fixtures and prestressing adjustment devices to prevent core deformation during the brazing process.

[0003] Furthermore, the uniformity of brazing temperature is a crucial factor in ensuring the brazing quality of large-sized, complex components, especially for multi-layered complex components such as plate-fin heat exchangers. Achieving a consistent temperature field requires longer holding times, leading to uneven brazing joint quality in different areas and creating localized weak points. Adding resistance heating to traditional single-radiation heating can achieve rapid heating, improving brazing efficiency and weld uniformity. However, while increasing heating efficiency, it also increases the difficulty of controlling local stress and deformation. Therefore, developing a dedicated constant-pressure fixture for large-sized, complex heat exchanger components using a dual-heat source vacuum brazing method combining lattice resistance heating and radiation heating is essential and of great significance for the application of new, high-efficiency, and highly reliable heat exchangers. Summary of the Invention

[0004] The purpose of this invention is to provide a high-efficiency constant pressure loading device and method for brazing heat exchange structures, which solves the problem of core and panel deformation during the brazing process of plate-fin heat exchangers.

[0005] To achieve the above objectives, this invention provides a high-efficiency brazing constant-pressure loading device for a heat exchange structure, comprising a disc spring constant-pressure sandwich plate, a cover plate, an insulating layer, a fastening long screw, and a pressure regulating screw. The disc spring constant-pressure sandwich plate and the cover plate are placed sequentially at the upper and lower ends of the heat exchange structure, respectively. The fastening long screw is used to fix the combination of the cover plate, the disc spring constant-pressure sandwich plate, and the heat exchange structure. Both the disc spring constant-pressure sandwich plate and the cover plate have an array of through holes, and an electrode is placed in each through hole. One end of the electrode is connected to the heat exchange structure, and the other end extends out of the cover plate. The insulating layer is provided between the disc spring constant-pressure sandwich plate and the heat exchange structure, between the disc spring constant-pressure sandwich plate and the electrode, and between the cover plate and the electrode. The pressure regulating screw is used to press the cover plate and the disc spring constant-pressure sandwich plate together. There are several pressure regulating screws arranged in an array.

[0006] The above-mentioned high-efficiency brazing constant pressure loading device for heat exchange structure includes a disc spring constant pressure sandwich plate comprising a pressure top plate, a plurality of disc springs and a pressure bottom plate; the plurality of disc springs are placed between the pressure top plate and the pressure bottom plate.

[0007] The above-mentioned heat exchange structure high-efficiency brazing constant pressure loading device has an array of threaded through holes on the cover plate, each threaded through hole is equipped with a pressure regulating screw, the pressure regulating screw is screwed into the threaded through hole, and the bottom of the pressure regulating screw rests on the disc spring constant pressure sandwich plate.

[0008] This invention also provides a method for efficient brazing constant pressure loading of a heat exchange structure, comprising: (1) installing the fins and panel of the heat exchange structure layer by layer, pre-powdered or foil-shaped brazing filler between the fins and the panel, and after assembling the heat exchange structure as a whole, installing disc spring constant pressure sandwich plates at the upper and lower ends respectively, and placing an insulating plate between the disc spring constant pressure sandwich plates and the heat exchange structure panel in advance; (2) installing cover plates at the upper and lower ends of the assembly of the heat exchange structure and the disc spring constant pressure sandwich plates respectively, and after installing and tightening long screws around the perimeter, keeping the assembly and the cover plates in a non-compressed state; (3) threading the cover plates. Install pressure regulating screws at the threaded through holes of the through hole array. After the bottom of the pressure regulating screws presses against the disc spring constant pressure sandwich plate, adjust all the pressure regulating screws to the predetermined pressure so that the heat exchange structure and the disc spring constant pressure sandwich plate assembly is fastened between the two cover plates; (4) Arrange an insulating layer in each through hole of the through hole array on the disc spring constant pressure sandwich plate and the cover plate, and then install an electrode in each through hole. The electrode is connected to the heat exchange structure panel and insulated from the disc spring constant pressure sandwich plate and the cover plate. After assembly, place it in the vacuum furnace and connect the electrodes to the furnace electrodes in sequence; (5) Evacuate the furnace to 1×10 -2 After Pa, start heating. When the temperature reaches 300-400℃, hold for 20-30 minutes. Continue heating while turning on the electrode current to assist heating. When the temperature rises to 30-50℃ above the melting point of the brazing filler metal, hold for 20-40 minutes. Then cool with the furnace to room temperature and remove.

[0009] The above-mentioned efficient brazing constant pressure loading method for heat exchange structure, wherein the disc spring constant pressure sandwich plate is a sandwich structure composed of a pressure top plate, 30 to 60 sets of disc springs and a pressure bottom plate. The disc springs are pre-arranged evenly on the pressure bottom plate and their positions are pre-fixed by spot welding. During installation, the pressure top plate is directly placed to form a combined sandwich plate for use.

[0010] The above-mentioned efficient brazing constant pressure loading method for heat exchange structure includes a pressure adjustment method whereby, after the pressure adjustment screws are pre-tightened during installation, a torque wrench is used to tighten them sequentially from the outside to the inside in symmetrical positions, ensuring that the pressure applied by each pressure adjustment screw meets the design requirements. The cumulative force applied to the disc spring constant pressure sandwich plate by the pressure adjustment screws is 0.01 to 0.05 MPa.

[0011] In the above-mentioned efficient brazing constant pressure loading method for heat exchange structure, the outer diameter of the disc spring is 16-30mm, the inner diameter is 8-15mm, the thickness is 0.4-0.6mm, the free height is 1.5-2.5mm, and the number of disc springs in a single array unit is 10-20.

[0012] In the above-mentioned efficient brazing constant pressure loading method for heat exchange structure, 20 to 40 groups of electrodes are arranged in an array from the inside to the outside. During the heating process of the vacuum furnace, the current of the electrodes in the center is set to be 2 to 5 times that of the electrodes on the outside, thereby accelerating the heating rate of the workpiece center.

[0013] In the above-mentioned efficient brazing constant pressure loading method for heat exchange structure, a layer of anti-welding agent is pre-sprayed onto the pressure top plate, disc spring, pressure bottom plate, fastening long screw, cover plate and pressure regulating screw.

[0014] In the above-mentioned efficient brazing constant pressure loading method for heat exchange structure, the pressure top plate and pressure bottom plate are made of 310s heat-resistant steel.

[0015] In the above-mentioned efficient brazing constant pressure loading method for heat exchange structure, the heat exchange structure panel can be made of titanium alloy, stainless steel or aluminum alloy, and the fins can be made of titanium alloy, copper or aluminum alloy.

[0016] Compared with the prior art, the beneficial technical effects of the present invention are:

[0017] This invention utilizes an array of disc springs to form a constant-pressure sandwich plate placed between the heat exchange structure and the cover plate. During room-temperature assembly, the constant-pressure sandwich plate is pressurized by a pressure regulating screw, and the disc springs resist deformation and store energy. When the expansion coefficient of the heat exchange structure is less than that of the loading device, the cover plate will not be able to secure the heat exchange structure during heating, resulting in poor contact at the welded parts, reduced weld quality, or even weld detachment. The constant-pressure sandwich plate can release deformation energy during heating, thereby maintaining the compressive stress between the heat exchange structure and the cover plate, promoting a tight fit between the fins and the panel, and ensuring weld quality. When the expansion coefficient of the heat exchange structure is greater than that of the loading device, the heat exchange structure is subjected to [unclear - possibly referring to stress or pressure] during heating. As the pressure on the cover plate gradually increases, when the internal stress exceeds the yield limit of the fins or panel, it will lead to local deformation and collapse, or even scrap the entire piece. During the heating process, the constant pressure sandwich plate can reduce the compressive stress between the heat exchange structure and the cover plate through elastic deformation, ensuring that the fins and panel do not undergo local collapse and deformation. The designed array-type pressure regulating screw can make micro-adjustments to the local pressure, taking into account the high rigidity on the outside and poor rigidity on the inside of the heat exchange structure. The pressure of the constant pressure sandwich plate by the individual screw can be controlled by the torque of the torque wrench. At the same time, the pressure of the loading device can be adjusted according to the welding pressure parameters required by different heat exchange structures, so as to control the loading conditions during the welding process within a stable range.

[0018] The through holes on the constant pressure sandwich plate and cover plate serve as mounting holes for resistance heating electrodes. The heating current for different parts of the heat exchange structure can be adjusted by arranging the array electrodes. Based on the characteristic that radiation heating causes rapid heating on the outer side and slow heating on the inner side, increasing the current in the inner region achieves rapid and uniform heating of the entire heat exchange structure, significantly improving welding efficiency. Simultaneously, the good temperature consistency between the inner and outer parts of the heat exchange structure reduces the time required to reach uniform temperature, avoiding inconsistencies in performance and excessive melting caused by different holding times in different areas. The ceramic insulating layer arranged on the contact surfaces between the heating electrodes and the constant pressure sandwich plate and cover plate, as well as between the heat exchange structure and the constant pressure sandwich plate, prevents short-circuit failure of the electrode current through the loading device. Considering that rapid initial heating is detrimental to the removal of impurity gases under vacuum, the resistance heating current is activated for rapid heating only after the heat exchange structure has been heated to 300–400°C and held for a period to remove impurity gases.

[0019] This invention develops a dedicated constant-pressure clamping device and method for welding large-size complex heat exchanger components using a dual heat source of rapid heat generation through a matrix resistance system and radiant heating. This solves the problem of controlling core and panel deformation during the brazing process of plate-fin heat exchangers, and also addresses issues such as poor local performance and defects caused by inconsistent internal and external temperatures. Compared with traditional brazing fixtures that rely solely on screw clamping and single radiant heating methods, the invention significantly improves weld quality consistency, yield, and welding efficiency, making it particularly suitable for large plate-fin heat exchanger products with high performance and reliability requirements. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the high-efficiency brazing constant pressure loading device for the heat exchange structure according to an embodiment of the present invention;

[0021] In the diagram, 1. Group A fins, 2. Panel, 3. Group B fins, 4. Pressure top plate, 5. Disc spring, 6. Pressure bottom plate, 7. Insulating bottom plate, 8. Fastening long screw, 9. Cover plate, 10. Pressure adjusting screw, 11. Electrode, 12. Power supply. Detailed Implementation

[0022] Combination Figure 1 The present invention provides a further detailed description of the efficient brazing constant pressure loading device and constant pressure loading method for the heat exchange structure.

[0023] Example 1

[0024] Install the heat exchange structure fins and panel layer by layer, pre-place powdered or foil-like brazing filler metal between the fins and panel. After assembling the entire heat exchange structure, install disc spring constant pressure sandwich plates on the top and bottom respectively. Place a layer of ceramic insulation plate between the disc spring constant pressure sandwich plate and the heat exchange structure panel. Install fastening cover plates on the top and bottom of the heat exchange structure and constant pressure sandwich plate assembly, and after installing fastening bolts around the perimeter, keep the assembly and cover plates in a non-compressed state. Install pressure regulating screws according to the array hole positions on the cover plates. After the bottom of the pressure regulating screws presses against the constant pressure sandwich plate, adjust all screws to the predetermined pressure, and fix the heat exchange structure and constant pressure sandwich plate assembly between the top and bottom cover plates. Install electrodes at the reserved through holes. After placing the assembled workpiece and mold in the vacuum furnace, connect the electrodes on the tooling to the electrodes inside the furnace in sequence. Evacuate the furnace to 1×10⁻⁶. -2 Heating begins after Pa, and once the temperature reaches 300℃, it is held for 20 minutes. Heating continues while simultaneously activating electrode current to assist workpiece heating. Once the workpiece temperature reaches 30℃ above the solder melting point, it is held for another 20 minutes. The workpiece is then cooled to room temperature in the furnace before being removed. The disc spring constant pressure sandwich plate consists of a pressure top plate, 30 sets of disc springs, and a pressure bottom plate. The disc springs are selected with an outer diameter of 20mm, an inner diameter of 10mm, a thickness of 0.6mm, and a free height of 1.5mm. Each array unit contains 20 disc springs. The cumulative force applied to the disc spring constant pressure sandwich plate via the pressure regulating screw is 0.01MPa. The 20 sets of electrodes are arranged in an array from the inside out. During the vacuum furnace heating process, the current of the electrodes in the center is set to be twice that of the outer electrodes. A layer of anti-welding flux is pre-sprayed onto the pressure top plate, disc springs, pressure bottom plate, fastening long screw, cover plate, and pressure regulating screw. The pressure top plate and pressure bottom plate are made of 310s heat-resistant steel. The heat exchange structure panel is made of aluminum alloy, and the fins are made of aluminum alloy.

[0025] Example 2

[0026] Install the heat exchange structure fins and panel layer by layer, pre-place powdered or foil-like brazing filler metal between the fins and panel. After assembling the entire heat exchange structure, install disc spring constant pressure sandwich plates on the top and bottom respectively. Place a layer of ceramic insulation plate between the disc spring constant pressure sandwich plate and the heat exchange structure panel. Install fastening cover plates on the top and bottom of the heat exchange structure and constant pressure sandwich plate assembly, and after installing fastening bolts around the perimeter, keep the assembly and cover plates in a non-compressed state. Install pressure regulating screws according to the array hole positions on the cover plates. After the bottom of the pressure regulating screws presses against the constant pressure sandwich plate, adjust all screws to the predetermined pressure, and fix the heat exchange structure and constant pressure sandwich plate assembly between the top and bottom cover plates. Install electrodes at the reserved through holes. After placing the assembled workpiece and mold in the vacuum furnace, connect the electrodes on the tooling to the electrodes inside the furnace in sequence. Evacuate the furnace to 1×10⁻⁶. -2 Heating begins after Pa, and the temperature is held at 350℃ for 25 minutes. Heating continues while the electrode current is activated to assist in workpiece heating. Once the workpiece temperature reaches 40℃ above the solder melting point, it is held for 30 minutes. The workpiece is then cooled to room temperature in the furnace before being removed. The disc spring constant pressure sandwich plate consists of a pressure top plate, 40 sets of disc springs, and a pressure bottom plate. The disc springs have an outer diameter of 16mm, an inner diameter of 8mm, a thickness of 0.5mm, and a free height of 1.5mm. Each array unit contains 14 disc springs. The cumulative force applied to the disc spring constant pressure sandwich plate via the pressure regulating screw is 0.02MPa. 25 sets of electrodes are arranged in an array from the inside out. During the vacuum furnace heating process, the current of the electrodes in the center is set to be three times that of the outer electrodes. A layer of anti-welding flux is pre-sprayed onto the pressure top plate, disc springs, pressure bottom plate, fastening long screw, cover plate, and pressure regulating screw. The pressure top plate and pressure bottom plate are made of 310s heat-resistant steel. The heat exchanger panel is made of stainless steel, and the fins are made of copper.

[0027] Example 3

[0028] Install the heat exchange structure fins and panel layer by layer, pre-place powdered or foil-like brazing filler metal between the fins and panel. After assembling the entire heat exchange structure, install disc spring constant pressure sandwich plates on the top and bottom respectively. Place a layer of ceramic insulation plate between the disc spring constant pressure sandwich plate and the heat exchange structure panel. Install fastening cover plates on the top and bottom of the heat exchange structure and constant pressure sandwich plate assembly, and after installing fastening bolts around the perimeter, keep the assembly and cover plates in a non-compressed state. Install pressure regulating screws according to the array hole positions on the cover plates. After the bottom of the pressure regulating screws presses against the constant pressure sandwich plate, adjust all screws to the predetermined pressure, and fix the heat exchange structure and constant pressure sandwich plate assembly between the top and bottom cover plates. Install electrodes at the reserved through holes. After placing the assembled workpiece and mold in the vacuum furnace, connect the electrodes on the tooling to the electrodes inside the furnace in sequence. Evacuate the furnace to 1×10⁻⁶. -2Heating begins after Pa, and the temperature is held at 350℃ for 30 minutes. Heating continues while the electrode current is activated to assist in workpiece heating. Once the workpiece temperature reaches 45℃ above the solder melting point, it is held for 35 minutes. The workpiece is then cooled to room temperature in the furnace before being removed. The disc spring constant pressure sandwich plate consists of a pressure top plate, 50 sets of disc springs, and a pressure bottom plate. The disc springs have an outer diameter of 24mm, an inner diameter of 10mm, a thickness of 0.4mm, and a free height of 2mm. Each array unit contains 10 disc springs. The cumulative force applied to the disc spring constant pressure sandwich plate via the pressure regulating screw is 0.03MPa. The 30 sets of electrodes are arranged in an array from the inside out. During the vacuum furnace heating process, the current of the electrodes in the center is set to be four times that of the outer electrodes. A layer of anti-welding flux is pre-sprayed onto the pressure top plate, disc springs, pressure bottom plate, fastening long screw, cover plate, and pressure regulating screw. The pressure top plate and pressure bottom plate are made of 310s heat-resistant steel. The heat exchange structure panel is made of titanium alloy, and the fins are also made of titanium alloy.

[0029] Example 4

[0030] Install the heat exchange structure fins and panel layer by layer, pre-place powdered or foil-like brazing filler metal between the fins and panel. After assembling the entire heat exchange structure, install disc spring constant pressure sandwich plates on the top and bottom respectively. Place a layer of ceramic insulation plate between the disc spring constant pressure sandwich plate and the heat exchange structure panel. Install fastening cover plates on the top and bottom of the heat exchange structure and constant pressure sandwich plate assembly, and after installing fastening bolts around the perimeter, keep the assembly and cover plates in a non-compressed state. Install pressure regulating screws according to the array hole positions on the cover plates. After the bottom of the pressure regulating screws presses against the constant pressure sandwich plate, adjust all screws to the predetermined pressure, and fix the heat exchange structure and constant pressure sandwich plate assembly between the top and bottom cover plates. Install electrodes at the reserved through holes. After placing the assembled workpiece and mold in the vacuum furnace, connect the electrodes on the tooling to the electrodes inside the furnace in sequence. Evacuate the furnace to 1×10⁻⁶. -2 Heating begins after Pa, and the temperature is held at 400℃ for 30 minutes. Heating continues while the electrode current is activated to assist in workpiece heating. Once the workpiece temperature reaches 50℃ above the solder melting point, it is held for 40 minutes. The workpiece is then cooled to room temperature in the furnace before being removed. The disc spring constant pressure sandwich plate consists of a pressure top plate, 60 sets of disc springs, and a pressure bottom plate. The disc springs have an outer diameter of 30mm, an inner diameter of 15mm, a thickness of 0.4mm, and a free height of 2.5mm. Each array unit contains 10 disc springs. The cumulative force applied to the disc spring constant pressure sandwich plate via the pressure regulating screw is 0.05MPa. The 40 sets of electrodes are arranged in an array from the inside out. During the vacuum furnace heating process, the current of the electrodes in the center is set to be 5 times that of the outer electrodes. A layer of anti-welding flux is pre-sprayed onto the pressure top plate, disc springs, pressure bottom plate, fastening long screw, cover plate, and pressure regulating screw. The pressure top plate and pressure bottom plate are made of 310s heat-resistant steel. The heat exchange structure panel is made of titanium alloy, and the fins are also made of titanium alloy.

Claims

1. A high-efficiency brazed constant-pressure loading device for heat exchange structure, characterized in that, The device includes a disc spring constant pressure sandwich plate, a cover plate, an insulating layer, a fastening long screw, and a pressure regulating screw. The disc spring constant pressure sandwich plate and the cover plate are placed sequentially at the upper and lower ends of the heat exchange structure, respectively. The fastening long screw is used to fix the combination of the cover plate, the disc spring constant pressure sandwich plate, and the heat exchange structure. Both the disc spring constant pressure sandwich plate and the cover plate have an array of through holes, and an electrode is placed in each through hole. One end of the electrode is connected to the heat exchange structure, and the other end extends out of the cover plate. The insulating layer is provided between the disc spring constant pressure sandwich plate and the heat exchange structure, between the disc spring constant pressure sandwich plate and the electrode, and between the cover plate and the electrode. The pressure regulating screw is used to press the cover plate and the disc spring constant pressure sandwich plate together. There are several pressure regulating screws, and the several pressure regulating screws are arranged in an array.

2. The high-efficiency brazing constant pressure loading device for heat exchange structure as described in claim 1, characterized in that, The disc spring constant pressure sandwich panel includes a pressure top plate, several disc springs, and a pressure bottom plate; the several disc springs are placed between the pressure top plate and the pressure bottom plate.

3. The high-efficiency brazing constant pressure loading device for heat exchange structure as described in claim 1, characterized in that, The cover plate has an array of threaded through holes, each threaded through hole is equipped with a pressure regulating screw, the pressure regulating screw is screwed into the threaded through hole, and the bottom of the pressure regulating screw rests on the disc spring constant pressure sandwich plate.

4. A method for efficient brazing and constant pressure loading of heat exchange structures, characterized in that, include: (1) Install the fins and panels of the heat exchange structure layer by layer, and pre-place powdered or foil-shaped brazing filler between the fins and the panels. After assembling the heat exchange structure as a whole, install disc spring constant pressure sandwich plates at the upper and lower ends respectively. Place an insulating plate between the disc spring constant pressure sandwich plates and the heat exchange structure panel in advance. (2) Install cover plates at the top and bottom ends of the assembly of the heat exchange structure and the disc spring constant pressure sandwich plate, and after installing and fastening long screws around the perimeter, the assembly and the cover plates are kept in a non-compressed state. (3) Install pressure regulating screws at the threaded through hole positions of the threaded through hole array on the cover plate. After the bottom of the pressure regulating screws presses against the disc spring constant pressure sandwich plate, adjust all the pressure regulating screws to the predetermined pressure so that the heat exchange structure and the disc spring constant pressure sandwich plate are fastened between the two cover plates. (4) An insulating layer is arranged in each through hole of the through hole array on the disc spring constant pressure sandwich plate and the cover plate, and then an electrode is installed in each through hole. The electrode is connected to the heat exchange structure panel and insulated from the disc spring constant pressure sandwich plate and the cover plate. After assembly, it is placed in the vacuum furnace and the electrode is connected to the furnace electrode in sequence. (5) Evacuate the furnace to a vacuum level of 1×10⁻⁶. -2 After Pa, start heating. When the temperature reaches 300-400℃, hold for 20-30 minutes. Continue heating while turning on the electrode current to assist heating. When the temperature rises to 30-50℃ above the melting point of the brazing filler metal, hold for 20-40 minutes. Then cool with the furnace to room temperature and remove.

5. The high-efficiency brazing constant pressure loading method for heat exchange structures according to claim 4, characterized in that, The disc spring constant pressure sandwich panel is a sandwich structure composed of a pressure top plate, 30 to 60 sets of disc springs and a pressure bottom plate. The disc springs are pre-arranged evenly on the pressure bottom plate and their positions are pre-fixed by spot welding. During installation, the pressure top plate is placed directly to form a combined sandwich panel for use.

6. The high-efficiency brazing constant pressure loading method for heat exchange structures according to claim 4, characterized in that, The method for adjusting the pressure of the pressure adjusting screw is to use a torque wrench to tighten it sequentially from the outside to the inside in symmetrical positions after the pressure adjusting screw is installed and pre-tightened, so as to ensure that the pressure applied by each pressure adjusting screw meets the design requirements. The cumulative force applied to the disc spring constant pressure sandwich plate through the pressure adjusting screw is 0.01 to 0.05 MPa.

7. The high-efficiency brazing constant pressure loading method for heat exchange structures according to claim 5, characterized in that: The disc springs have an outer diameter of 16–30 mm, an inner diameter of 8–15 mm, a thickness of 0.4–0.6 mm, a free height of 1.5–2.5 mm, and a number of disc springs in a single array unit of 10–20.

8. The high-efficiency brazing constant pressure loading method for heat exchange structures according to claim 4, characterized in that, 20 to 40 groups of electrodes are arranged in an array from the inside to the outside. During the heating process of the vacuum furnace, the current of the electrodes in the center is set to be 2 to 5 times that of the electrodes on the outside, which accelerates the heating rate of the workpiece center.

9. The high-efficiency brazing constant pressure loading method for heat exchange structures according to claim 5, characterized in that: A layer of anti-welding agent is pre-sprayed onto the pressure top plate, disc spring, pressure bottom plate, fastening long screw, cover plate and pressure adjusting screw.

10. The high-efficiency brazing constant pressure loading method for heat exchange structures according to claim 5, characterized in that, The pressure top plate and pressure bottom plate are made of 310s heat-resistant steel; the heat exchange structure panel is made of titanium alloy, stainless steel or aluminum alloy, and the fins are made of titanium alloy, copper or aluminum alloy.

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