Titanium alloy plate-fin heat exchanger vacuum brazing equipment with air cooling system

Abstract

A titanium alloy plate-fin heat exchanger vacuum brazing device with an air cooling system relates to the field of brazing and comprises a furnace body used for providing a vacuum environment and accommodating a part to be welded; the vacuum system is used for discharging gas in the furnace body to obtain a vacuum environment; the furnace pipe is arranged in the furnace body; and the gas circulating cooling system is connected with the furnace body to form a closed cavity for cooling. The production efficiency is improved through the gas cooling circulation flow field design, the specific structure of the gas circulation cooling system and the cooling process control mode. The problem that the cooling uniformity of the plate-fin heat exchangers arranged in a staggered mode under the forced circulation cooling condition is difficult to control is solved, the brazing production efficiency is greatly improved, and the situation that the quality of brazing seams is seriously affected by out-of-tolerance thermal stress deformation is avoided.

Description

Technical Field

[0001] The utility model belongs to the brazing technology in the field of high-end equipment manufacturing, and particularly relates to a vacuum brazing device for a titanium alloy plate-fin heat exchanger with an air-cooling system. Background Art

[0002] Due to the characteristics of the multi-layer combination and the self-shielding structure between layers of the large-size titanium alloy plate-fin heat exchanger, when using traditional vacuum brazing equipment, there is usually no gas circulation cooling system, and the furnace cooling method is adopted, resulting in the problem of slow cooling speed, which in turn leads to a long brazing process cycle and low production efficiency. If the existing gas circulation cooling system structure is adopted, the gas cooling method of uniformly spraying gas along the circumferential direction of 360° or one-way blowing is generally used, it is difficult to ensure the cooling uniformity of the staggered plate-fin heat exchanger structure, often resulting in large thermal stress deformation, seriously affecting the weld quality, and reducing the pressure resistance of the high-performance plate-fin heat exchanger. Summary of the Utility Model

[0003] Aiming at the above problems, the utility model provides a vacuum brazing device for a titanium alloy plate-fin heat exchanger with an air-cooling system, which can realize the rapid and uniform cooling of the large-size titanium alloy plate-fin heat exchanger.

[0004] According to one aspect of the utility model, there is provided a vacuum brazing device for a titanium alloy plate-fin heat exchanger with an air-cooling system, which includes: a furnace body for providing a vacuum environment and accommodating the workpiece to be welded; a vacuum system connected to the furnace body, which is used to discharge the gas in the furnace body to obtain a vacuum environment; a furnace liner, which is arranged in the furnace body, the furnace liner is provided with a side air inlet and a side small heat insulation screen in the first direction, and a rear air return port and a rear small heat insulation screen in the second direction, the side air inlet and the rear air return port are used to guide the air flow in and out of the furnace liner, the side small heat insulation screen and the rear small heat insulation screen are used to maintain the high-temperature state in the furnace liner, the furnace liner is provided with openings at the front and rear, and is provided with a furnace liner rear cover and a furnace liner front cover; a gas circulation cooling system, which is connected to the furnace body to form a closed chamber, the gas circulation cooling system includes a circulation fan, a furnace liner air inlet duct, a furnace liner air outlet duct and a heat exchanger, the circulation fan blows the low-temperature air flow into the space between the furnace liner and the furnace body through the furnace liner air inlet duct, the low-temperature air flow bypasses the side small heat insulation screen of the furnace liner and flows into the furnace liner from the side air inlet, the high-temperature gas after fully cooling the brazed plate-fin heat exchanger flows out from the rear air outlet of the furnace liner, bypasses the rear small heat insulation screen of the furnace liner and enters the furnace liner air outlet duct, and is cooled to low-temperature gas by flowing through the heat exchanger, and the low-temperature gas is sucked by the circulation fan and enters the next forced circulation.

[0005] Further, the air inlet duct of the furnace liner includes a front seal plate, a tee joint, and a double-inlet duct. The main pipe interface of the tee joint is connected to the circulation fan, and the two branch pipe interfaces of the tee joint are connected to the double-inlet duct, so as to introduce the low-temperature air flow of the circulation fan into the furnace body through the tee joint and the double-inlet duct. Both ends of the front seal plate are respectively connected to the inner wall of the furnace body and the outer wall of the furnace liner. The front seal plate is used to guide the low-temperature air flow to bypass the small heat insulation screen on the side of the furnace liner and flow into the air inlet on the side of the furnace liner.

[0006] Further, the air outlet duct of the furnace liner includes a wind guide cover, a collector, and a return air duct that are connected in sequence. The heat exchanger is arranged inside the air outlet duct of the furnace liner. The wind guide cover is arranged outside the furnace liner. The wind guide cover is connected to the heat exchanger to communicate the rear air return opening of the furnace liner and the collector. One end of the return air duct is communicated with the air inlet of the circulation fan, and the other end of the return air duct is communicated with the air outlet at the center of the rear end of the furnace body.

[0007] Further, a load thermocouple is arranged inside the furnace liner.

[0008] Further, multiple load thermocouples are arranged on the surface and the core of the heat exchanger respectively. When the temperature difference measured by the load thermocouple is greater than the set value, the rotation speed of the circulation fan is reduced or the gas pressure inside the furnace body is reduced, so as to reduce the cooling speed and reduce the temperature difference between the core and the surface of the product.

[0009] Further, the air flow direction entering the furnace body from the double-inlet duct is parallel to the side wall of the furnace liner and perpendicular to the rear cover of the furnace liner.

[0010] Further, the length of the wind guide cover is adjustable to ensure contact with the rear cover of the furnace liner during assembly.

[0011] Further, the collector is in the shape of a conical ring, with the cone bottom facing the heat exchanger, and the inner diameter of the cone mouth is larger than the outer diameter of the return air duct.

[0012] Further, the vacuum system includes a vacuum pump, a vacuum valve, and pipelines. The vacuum pump is connected to the furnace body through pipelines, and a vacuum valve is arranged on the pipelines.

[0013] Further, there are multiple side air inlets, which are evenly distributed on both sides of the furnace liner.

[0014] Applying the technical solution of the present utility model, the production efficiency is improved through the design of the gas cooling circulation flow field, the specific structure of the gas circulation cooling system, and the control method of the cooling process. Specifically, compared with the traditional vacuum brazing equipment, a gas circulation cooling system is added. The gas circulation path and direction of this system are highly matched with the structural characteristics of the staggered arrangement of the plate-fin heat exchanger, with both horizontal airflows and vertical airflows, enabling all points inside the plate-fin heat exchanger to be cooled simultaneously. In addition, load thermocouples are respectively arranged on the surface and the core of the plate-fin heat exchanger to measure the core surface temperature in real time. When the temperature difference is greater than the set value, the rotation speed of the circulation fan is reduced or the gas pressure inside the furnace body is reduced, thereby appropriately reducing the cooling speed and reducing the core surface temperature difference of the product. By adopting the above solution, the current situation that the titanium alloy plate-fin heat exchanger can only be slowly cooled with the furnace is changed, the problem of difficult control of the cooling uniformity of the plate-fin heat exchanger with a staggered arrangement under forced circulation cooling conditions is solved, the brazing production efficiency is greatly improved, and the serious influence of thermal stress deformation on the brazing weld quality is avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 FIG. is a schematic diagram (top view) of the gas circulation of the high-efficiency vacuum brazing equipment for manufacturing a plate-fin heat exchanger provided by an embodiment of the present utility model;

[0016] Figure 2 FIG. is a plan view (top view) of the high-efficiency vacuum brazing equipment for manufacturing a plate-fin heat exchanger provided by an embodiment of the present utility model;

[0017] Figure 3 FIG. is a front view of the vacuum brazing equipment provided by an embodiment of the present utility model;

[0018] Figure 4 FIG. is a right view of the high-efficiency vacuum brazing equipment for manufacturing a plate-fin heat exchanger provided by an embodiment of the present utility model;

[0019] Figure 5 FIG. is a schematic structural diagram of a titanium alloy plate-fin heat exchanger.

[0020] Among them, the above-mentioned drawings include the following reference numerals:

[0021] 10. Furnace body,

[0022] 20. Vacuum system, 21. Vacuum pump, 22. Vacuum valve, 23. Pipeline,

[0023] 30. Furnace liner, 31. Side air inlet, 32. Side small heat insulation screen, 33. Rear air outlet, 34. Rear small heat insulation screen, 35. Furnace liner rear cover, 36. Furnace liner front cover;

[0024] 40. Gas circulation cooling system, 41. Circulation fan, 411. Central inlet, 412. End outlet, 42. Furnace liner air inlet duct, 421. Front seal plate, 422. Three-way joint, 423. Double air inlet pipe, 43. Furnace liner air outlet duct, 431. Air guide cover, 432. Air collector, 433. Return air duct, 44. Heat exchanger;

[0025] 50. Load thermocouple. Detailed implementation manners

[0026] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments may be combined with each other. The technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way restricts the present utility model and its application or use. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0027] It should be noted that the terms used herein are only for describing the specific implementation manners and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless otherwise clearly specified in the context, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0028] Unless otherwise specifically stated, the relative arrangements of the components and steps set forth in these embodiments, numerical expressions and values do not limit the scope of the present utility model. At the same time, it should be understood that, for the convenience of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and devices should be regarded as part of the authorized specification. In all the examples shown and discussed herein, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numerals and letters denote like items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0029] Such as Figures 1 to 5As shown in the figure, according to a specific embodiment of the present utility model, a vacuum brazing equipment for a titanium alloy plate-fin heat exchanger with an air-cooling system is provided, including a furnace body 10 for providing a vacuum environment and accommodating workpieces to be welded; a vacuum system 20, which is connected to the furnace body 10 and is used to discharge the gas in the furnace body 10 to obtain a vacuum environment; a furnace liner 30, which is arranged in the furnace body 10. The furnace liner 30 is provided with a side air inlet 31 and a side small heat insulation screen 32 in the first direction, and a rear air return port 33 and a rear small heat insulation screen 34 in the second direction. The side air inlet 31 and the rear air return port 33 are used to guide the air flow in and out of the furnace liner, and the side small heat insulation screen 32 and the rear small heat insulation screen 34 are used to maintain the high-temperature state in the furnace liner 30. The furnace liner 30 is provided with openings at the front and rear, and is provided with a furnace liner rear cover 35 and a furnace liner front cover 36; a gas circulation cooling system 40, which is connected to the furnace body 10 to form a closed chamber. The gas circulation cooling system 40 includes a circulation fan 41, a furnace liner air inlet duct 42, a furnace liner air outlet duct 43 and a heat exchanger 44. The circulation fan 41 blows low-temperature air flow into the space between the furnace liner 30 and the furnace body 10 through the furnace liner air inlet duct 42. The low-temperature air flow bypasses the side small heat insulation screen 32 of the furnace liner 30 and flows into the furnace liner 30 from the side air inlet 31. The high-temperature gas after fully cooling the brazed plate-fin heat exchanger flows out from the rear air outlet 33 of the furnace liner 30, bypasses the rear small heat insulation screen 34 of the furnace liner 30 and enters the furnace liner air outlet duct 43, and is cooled to low-temperature gas after flowing through the heat exchanger 44. The low-temperature gas is sucked by the circulation fan 41 and enters the next forced circulation.

[0030] Applying this configuration method, through the design of the gas cooling circulation flow field, the specific structure of the gas circulation cooling system, and the cooling process control method, the production efficiency is improved. Specifically, compared with traditional vacuum brazing equipment, a gas circulation cooling system is added. The gas circulation path and direction of this system highly match the structural characteristics of the staggered arrangement of the plate-fin heat exchanger, with both horizontal air flow and vertical air flow, which can cool each point inside the plate-fin heat exchanger simultaneously. By adopting the above scheme, the current situation that the titanium alloy plate-fin heat exchanger can only be slowly cooled with the furnace is changed, and the problem that it is difficult to control the cooling uniformity of the staggered plate-fin heat exchanger under forced circulation cooling conditions is solved. The brazing production efficiency is greatly improved, and the serious influence of thermal stress deformation on the quality of the brazing weld is avoided.

[0031] Furthermore, as Figure 4As shown in the figure, to optimize the intake air flow path, the furnace liner intake air duct 42 includes a front seal plate 421, a tee 422, and a double-intake air duct 423. The main pipe interface of the tee 422 is connected to the circulation fan 41, and the two branch pipe interfaces of the tee 422 are connected to the double-intake air duct 423, so as to introduce the low-temperature air flow of the circulation fan 41 into the furnace body 10 through the tee 422 and the double-intake air duct 423. The two ends of the front seal plate 421 are respectively connected to the inner wall of the furnace body 10 and the outer wall of the furnace liner 30. The front seal plate 421 is used to guide the low-temperature air flow to bypass the small heat insulation screen 32 on the side of the furnace liner 30 and flow into the furnace liner 30 from the side air inlet 31.

[0032] With this configuration, through the combined design of the tee 422 and the double-intake air duct 423, the low-temperature air flow generated by the circulation fan 41 can be more evenly and efficiently distributed to both sides of the furnace liner 30. This design effectively reduces the loss and turbulence of the air flow during transmission, enabling the low-temperature air flow to enter the furnace liner 30 more directly and smoothly, thereby improving the heat exchange efficiency and accelerating the uniform distribution of the temperature in the furnace and the heating rate. The design of the front seal plate 421 cleverly guides the low-temperature air flow to bypass the small heat insulation screen 32 on the side of the furnace liner 30 and enter the furnace liner. This not only maintains the heat insulation effect of the small heat insulation screen to prevent the direct radiation of the high temperature in the furnace to the external structure but also ensures the effective utilization of the low-temperature air flow. This design helps to reduce the ineffective dissipation of heat energy, reduces the energy consumption of the entire system, and enables the low-temperature air flow to circulate smoothly, which to a certain extent reduces the dust accumulation and pollutant deposition in the area around the furnace liner. In addition, this design also provides convenience for subsequent maintenance and cleaning work, reducing the maintenance cost and difficulty.

[0033] Furthermore, as Figure 2 and Figure 3 shown, to optimize the outlet air flow path, the furnace liner outlet air duct 43 includes a wind guide cover 431, a collector 432, and a return air duct 433 connected in sequence. The heat exchanger 44 is arranged inside the furnace liner outlet air duct 43. The wind guide cover 431 is arranged outside the furnace liner 30. The wind guide cover 431 is connected to the heat exchanger 44 to communicate the rear return air outlet 33 of the furnace liner and the collector 432. One end of the return air duct 433 is communicated with the air inlet of the circulation fan 41, and the other end of the return air duct 433 is communicated with the air outlet at the center of the rear end of the furnace body 10.

[0034] With this configuration, by directly arranging the heat exchanger 44 inside the furnace liner outlet air duct 43, especially connected to the wind guide cover 431, the heat energy in the high-temperature gas discharged from the furnace liner 30 can be efficiently captured and recovered. This design ensures that the high-temperature gas can fully exchange heat with the heat exchanger before leaving the furnace liner, thereby improving the heat recovery efficiency.

[0035] Furthermore, as Figure 2 shown, to precisely control the cooling rate, a load thermocouple 50 is arranged inside the furnace liner 30.

[0036] Further, as Figure 2 shown, to reduce the temperature difference between the surface and the core of the product, a plurality of load thermocouples 50 are arranged on the surface and the core of the heat exchanger 44 respectively. When the temperature difference measured by the load thermocouples 50 is greater than the set value, the rotation speed of the circulation fan 41 is reduced or the gas pressure in the furnace body 10 is reduced, so as to reduce the cooling rate and the temperature difference between the surface and the core of the product.

[0037] Applying this configuration method, load thermocouples are arranged on the surface and the core of the plate-fin heat exchanger respectively to measure the surface and core temperatures in real time. When the temperature difference is greater than the set value, the rotation speed of the circulation fan is reduced or the gas pressure in the furnace body is reduced, so as to appropriately reduce the cooling rate and the temperature difference between the surface and the core of the product.

[0038] Further, as Figure 1 shown, to further improve the cooling efficiency, the air flow direction entering the furnace body 10 from the double-inlet air duct 423 is parallel to the side wall of the furnace liner 30 and perpendicular to the rear cover of the furnace liner 30.

[0039] Further, to enhance the compactness and integration of the system and improve the flexibility of the system, the length of the air guide cover 431 is adjustable to ensure contact with the rear cover of the furnace liner during assembly.

[0040] Further, to optimize the air flow distribution and reduce the pressure loss, the collector 432 is in the shape of a tapered ring, with the tapered bottom facing the heat exchanger 44 and the inner diameter of the tapered opening being greater than the outer diameter of the return air duct 433.

[0041] Further, to achieve precise control and rapid adjustment of the vacuum degree in the furnace, the vacuum system 20 includes a vacuum pump 21, a vacuum valve 22 and a pipeline 23. The vacuum pump 21 is connected to the furnace body 10 through the pipeline 23, and a vacuum valve 22 is provided on the pipeline 23.

[0042] To further understand the present invention, the following combines Figures 1 to 5 to describe in detail the vacuum brazing equipment for titanium alloy plate-fin heat exchangers with an air-cooling system of the present invention. As Figure 1 and Figure 2 shown, the vacuum brazing equipment for titanium alloy plate-fin heat exchangers with an air-cooling system includes:

[0043] A furnace body 10 for providing a vacuum environment and accommodating the parts to be welded;

[0044] A vacuum system 20, which is composed of a vacuum pump 21, a vacuum valve 22 and a pipeline 23. The vacuum pump 21 is connected to the furnace body 10 through the pipeline 23, and a vacuum valve 22 is provided on the pipeline 23.

[0045] The furnace liner 30 is arranged inside the furnace body 10. The furnace liner 30 includes side air inlets 31, side small heat insulation screens 32, rear air return openings 33, rear small heat insulation screens 34, a furnace liner rear cover 35 and a furnace liner front cover 36. The furnace liner 30 is provided with openings at the front and rear. There are multiple side air inlets 31, which are evenly distributed on both sides of the furnace liner 30. Side small heat insulation screens 32 are installed on both sides of the furnace liner 30. Multiple rear air return openings 33 are evenly distributed on the furnace liner rear cover 36, and a rear small heat insulation screen 32 is arranged on the furnace liner rear cover 36. Multiple load thermocouples 50 are arranged inside the furnace liner 30, and are respectively arranged on the surface and the core of the heat exchanger 44.

[0046] The gas circulation cooling system 40 is connected to the furnace body 10 through a flange with a sealing ring to form a sealed chamber. The gas circulation cooling system 40 includes a circulation fan 41, a furnace liner air inlet duct 42, a furnace liner air outlet duct 43 and a heat exchanger 4. In addition, the gas circulation cooling system can also adopt an internal circulation structure, and the circulation fan is directly connected to the furnace body.

[0047] The circulation fan 41, when the temperature difference measured by the load thermocouple 50 is greater than the set value, reduces the rotation speed of the circulation fan 41 or reduces the gas pressure inside the furnace body 10, thereby reducing the cooling speed and reducing the temperature difference between the core and the surface of the product. The circulation fan 41 is arranged outside the furnace body 10 and is connected to the furnace body 10 through a pipeline. The circulation fan 41 has a central inlet 411 and an end outlet 412.

[0048] The furnace liner air inlet duct 42 includes a front seal plate 421, a tee 422 and a double air inlet pipe 423. The annular space with a round outer and square inner shape is composed of the double air inlet pipe, the inner wall of the furnace body, the outside of the collector, the outside of the air guide cover, the outer wall of the furnace liner and the front seal plate. The two air outlets of the double air inlet pipe 423 are respectively connected to the air inlets arranged up and down at the rear end of the furnace body 10. The air inlets are connected to the tee 422, and the tee 422 is connected to the air outlet of the circulation fan 41. The air flow direction entering the furnace body 10 from the double air inlet pipe 423 is parallel to the side wall of the furnace liner and perpendicular to the furnace liner rear cover. The front seal plate 421 is close to the furnace liner front cover, and its two ends are respectively connected to the inner wall of the furnace body 10 and the outer wall of the furnace liner 30. The front seal plate 421 is used to guide the low-temperature air flow to bypass the side small heat insulation screen 32 of the furnace liner 30 and flow into the furnace liner 30 from the side air inlets 31.

[0049] The air outlet duct 43 of the furnace liner is connected to the furnace liner 30. The air outlet duct 43 of the furnace liner consists of a wind guide cover 431, a collector 432 and a return air duct 433. The length of the wind guide cover 431 is adjustable to ensure contact with the rear cover of the furnace liner during assembly, closing the space from the rear cover of the furnace liner to the heat exchanger. The air outlet duct of the furnace liner is composed of the space formed by the outer wall of the rear cover of the furnace liner, the inner side of the wind guide cover, the heat exchanger, the inner side of the collector and the return air duct. The heat exchanger 44 is arranged inside the air outlet duct 43 of the furnace liner. The wind guide cover 431 is arranged outside the furnace liner 30. The wind guide cover 431 is connected to the heat exchanger 44, connecting the rear air return opening 33 of the furnace liner and the collector 432. One end of the return air duct 433 is connected to the air inlet of the circulation fan 41, and the other end of the return air duct 433 is connected to the air outlet at the center of the rear end of the furnace body 10. Among them, the collector is in the shape of a conical ring, with the conical bottom facing the heat exchanger and the inner diameter of the conical opening being larger than the outer diameter of the return air duct.

[0050] The heat exchanger 44 is fixedly arranged inside the furnace body 10. One end of the heat exchanger 44 is respectively connected to the wind guide cover 431 and the collector 432, and the other end of the heat exchanger 44 is connected to the air outlet duct 43 of the furnace liner. The heat exchanger 44 is a finned tube or plate fin type heat exchanger.

[0051] The gas circulation path of the gas circulation cooling system 40 is that the circulation fan 41 blows low-temperature air flow between the outer wall of the furnace liner 30 and the inner wall of the furnace body 10. The low-temperature air flow bypasses the small heat insulation screen 31 on the side of the furnace liner and flows into the furnace liner 30 from the side air inlet 31. The high-temperature gas after fully cooling the brazed plate fin heat exchanger flows out from the rear air outlet 33 of the furnace liner 30, bypasses the small heat insulation screen 34 at the rear of the furnace liner and enters the wind guide cover 431, and then flows through the heat exchanger 44 and is cooled into low-temperature gas, and finally is sucked by the circulation fan 41 to enter the next forced circulation.

Claims

1. A vacuum brazing equipment for titanium alloy plate-fin heat exchanger with an air-cooling system, characterized in that The vacuum brazing equipment for titanium alloy plate-fin heat exchanger with an air-cooling system includes: A furnace body (10) for providing a vacuum environment and accommodating the workpieces to be welded; A vacuum system (20) connected to the furnace body (10), which is used to exhaust the gas in the furnace body (10) to obtain a vacuum environment; A furnace liner (30) disposed inside the furnace body (10). The furnace liner (30) is provided with a side air inlet (31) and a side small heat insulation screen (32) in the first direction, and a rear air return opening (33) and a rear small heat insulation screen (34) in the second direction. The side air inlet (31) and the rear air return opening (33) are used to guide the air flow in and out of the furnace liner. The side small heat insulation screen (32) and the rear small heat insulation screen (34) are used to maintain the high-temperature state inside the furnace liner (30). The furnace liner (30) is provided with openings at the front and rear, and is provided with a furnace liner rear cover (35) and a furnace liner front cover (36); A gas circulation cooling system (40) connected to the furnace body (10) to form a closed chamber. The gas circulation cooling system (40) includes a circulation fan (41), a furnace liner air inlet duct (42), a furnace liner air outlet duct (43) and a heat exchanger (44). The circulation fan (41) blows the low-temperature air flow into the space between the furnace liner (30) and the furnace body (10) through the furnace liner air inlet duct (42). The low-temperature air flow bypasses the side small heat insulation screen (32) of the furnace liner (30) and flows into the furnace liner (30) from the side air inlet (31). The high-temperature gas after fully cooling the brazed plate-fin heat exchanger flows out from the rear air outlet (33) of the furnace liner (30), bypasses the rear small heat insulation screen (34) of the furnace liner (30) and enters the furnace liner air outlet duct (43), and is cooled to a low-temperature gas after flowing through the heat exchanger (44). The low-temperature gas is sucked by the circulation fan (41) to enter the next forced circulation.

2. The vacuum brazing equipment for a titanium alloy plate-fin heat exchanger with an air-cooling system according to claim 1, wherein, The furnace liner air inlet duct (42) includes a front sealing plate (421), a tee (422) and a double-inlet duct (423). The main pipe interface of the tee (422) is connected to the circulation fan (41), and the two branch pipe interfaces of the tee (422) are connected to the double-inlet duct (423) to introduce the low-temperature air flow of the circulation fan (41) into the furnace body (10) through the tee (422) and the double-inlet duct (423). The two ends of the front sealing plate (421) are respectively connected to the inner wall of the furnace body (10) and the outer wall of the furnace liner (30). The front sealing plate (421) is used to guide the low-temperature air flow to bypass the side small heat insulation screen (32) of the furnace liner (30) and flow into the furnace liner (30) from the side air inlet (31).

3. A vacuum brazing apparatus for a titanium alloy plate fin heat exchanger with an air cooling system according to claim 1, characterized in that, The described furnace liner air outlet air duct (43) includes a wind guide cover (431), a collector (432), and a return air duct (433) connected in sequence. The heat exchanger (44) is disposed inside the furnace liner air outlet air duct (43). The wind guide cover (431) is disposed outside the furnace liner (30). The wind guide cover (431) is connected to the heat exchanger (44) to communicate the rear air return opening (33) of the furnace liner and the collector (432). One end of the return air duct (433) is communicated with the air inlet of the circulation fan (41), and the other end of the return air duct (433) is communicated with the air outlet at the center of the rear end of the furnace body (10).

4. A vacuum brazing apparatus for a titanium alloy plate-fin heat exchanger with an air-cooling system according to any one of claims 1 to 3, characterized in that A load thermocouple (50) is disposed inside the described furnace liner (30).

5. The vacuum brazing equipment for a titanium alloy plate-fin heat exchanger with an air-cooling system according to claim 4, characterized in that A plurality of load thermocouples (50) are provided and are respectively arranged on the surface and the core of the heat exchanger (44). When the temperature difference measured by the load thermocouple (50) is greater than a set value, the rotation speed of the circulation fan (41) is reduced or the gas pressure inside the furnace body (10) is reduced, so as to reduce the cooling speed and reduce the temperature difference between the core and the surface of the product.

6. A vacuum brazing apparatus for a titanium alloy plate-fin heat exchanger with an air-cooling system according to claim 2, characterized in that, The air flow direction entering the furnace body (10) from the double air inlet duct (423) is parallel to the side wall of the furnace liner (30) and perpendicular to the rear cover of the furnace liner (30).

7. A vacuum brazing apparatus for a titanium alloy plate-fin heat exchanger with an air-cooling system according to claim 3, characterized in that, The length of the wind guide cover (431) is adjustable to ensure contact with the rear cover of the furnace liner during assembly.

8. The vacuum brazing equipment for a titanium alloy plate-fin heat exchanger with an air-cooling system according to claim 3, characterized in that The collector (432) is in the shape of a conical ring, with the conical bottom facing the heat exchanger (44), and the inner diameter of the conical opening is greater than the outer diameter of the return air duct (433).

9. The vacuum brazing equipment for a titanium alloy plate-fin heat exchanger with an air-cooling system according to claim 1, characterized in that The described vacuum system (20) includes a vacuum pump (21), a vacuum valve (22), and a pipeline (23). The vacuum pump (21) is communicated with the furnace body (10) through the pipeline (23), and a vacuum valve (22) is provided on the pipeline (23).

10. A vacuum brazing apparatus for a titanium alloy plate-fin heat exchanger with an air-cooling system according to claim 1, characterized in that A plurality of the described side air inlets (31) are evenly distributed on both sides of the furnace liner (30).

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