Integrated sealing structure of elliptical vacuum heat exchange tube and heat exchanger

Abstract

The application discloses a sealing structure of an integrated elliptical vacuum heat exchange pipe and a heat exchanger, and relates to the technical field of heat exchange pipes.

Description

Technical Field

[0001] This application relates to the field of heat exchange technology, and in particular to an integrated elliptical vacuum heat exchange tube sealing structure and heat exchanger. Background Technology

[0002] Vacuum heat exchange tubes (heat pipes) are the core heat exchange elements of low-temperature economizers and waste heat recovery devices in coal-fired power plants. Their sealing performance and internal vacuum level directly determine the heat exchange efficiency, operational stability and service life of the heat exchange system.

[0003] The most common traditional heat pipe forming method in the industry is the heating and venting method, which involves injecting the working fluid into the heat pipe blank and heating it to expel the air inside the pipe along with the working fluid vapor, and then quickly sealing it.

[0004] However, heat pipes sealed using the traditional heating and venting method generally have a low internal vacuum. The residual mass inside the heat pipe cannot be accurately guaranteed, causing the heat transfer during service to deviate significantly from the design value, and even leading to negative effects such as overheating. In addition, there are a lot of non-condensable gases (such as air and water vapor) remaining inside the shell. These non-condensable gases are very easy to accumulate and block the heat transfer path during heat pipe operation, resulting in increased thermal resistance and slower thermal response. They usually face the risk of failure within 1 to 3 years, and have extremely low long-term reliability.

[0005] In addition, the end packaging of traditional heat pipes usually uses separate end caps for separate welding, or conventional brazing is used to seal them after clamping. Such rough welding and sealing processes are prone to metallographic degradation and intergranular leakage when facing the alternating temperature difference stress of harsh industrial operating environments, which can lead to complete destruction of vacuum. Summary of the Invention

[0006] This application aims to at least partially solve one of the technical problems in the aforementioned technologies.

[0007] To achieve the above objectives, the first aspect of this application proposes an integrated elliptical vacuum heat exchanger tube sealing structure, comprising: a tube body with an elliptical axial cross-section, including a tail end integrally fused by heat fusion and a radially contracting and outwardly extending head end to form a chamber for accommodating the heat exchange medium; a suction tube connected to the head end for discharging gas from the chamber by negative pressure suction; and a gas nozzle cap disposed at the opening of the suction tube for sealing the chamber after evacuation.

[0008] In addition, the herb seed spreading device proposed in this application may also have the following additional technical features:

[0009] As a further description of the above technical solution: the tail end is a closed end cap that is arc-shaped or flat.

[0010] As a further description of the above technical solution: a straight air extraction channel is formed inside the suction tube, which communicates with the chamber.

[0011] As a further description of the above technical solution: the nozzle cap is provided with a quick-release female connector for detachable connection with the quick-release male connector of an external negative pressure suction device, and the quick-release female connector has a built-in self-sealing valve core.

[0012] As a further description of the above technical solution: the tube body, the tail end, the head end and the suction tube are all made of the same metal material.

[0013] As a further description of the above technical solution: the valve cap is provided with an indicating device, which includes a pointer, a drive structure, a sealing valve, and a temperature memory spring. The valve cap contains a retractable valve seat, and the sealing valve is axially movable within the valve seat, forming a separable, airtight seal with the valve seat. One end of the temperature memory spring is connected to the sealing valve, and the other end is connected to the valve seat. The pointer is rotatably mounted on the outer dial of the valve cap. The power input end of the drive structure is connected to the sealing valve, and the power output end is connected to the pointer, so that when the sealing valve is displaced, the drive structure drives the pointer to rotate.

[0014] As a further description of the above technical solution: the drive structure includes a push rod, a sector tooth, and a gear, wherein the gear is disposed inside the air nozzle cap and is coaxially disposed with the rotating end of the pointer; the sector tooth is rotatably disposed inside the air nozzle cap, and the sector tooth includes a concentrically arranged arc-shaped tooth portion and a rotating portion, wherein the arc-shaped tooth portion meshes with the gear; one end of the push rod is rotatably connected to the sealing valve, and the other end is eccentrically pivotally connected to the rotating portion.

[0015] As a further description of the above technical solution: the valve seat includes an axially connected cylindrical cavity and a contraction cavity, wherein the small-diameter end of the contraction cavity forms an exhaust port that communicates with the suction tube, and the outer edge of the exhaust port is provided with a shoulder; wherein one end of the temperature memory spring is connected to the shoulder, and the other end is connected to the sealing valve.

[0016] As a further description of the above technical solution: the sealing valve includes a sliding part, a valve body, a sealing ring, an extension rod, and a connecting block, wherein the sliding part is embedded and slides within the cylindrical cavity, and a vent is provided on the side of the sliding part; the hemispherical valve body is disposed on the sliding part; the sealing ring is embedded outside the valve body and selectively and airtightly fits against the inner wall of the contraction cavity; one end of the extension rod is connected to the valve body, and the other end passes through the vent and extends toward one side of the suction tube; the connecting block is disposed on the extension end of the extension rod; wherein the temperature memory spring is sleeved on the extension rod, and one end is connected to the shoulder, and the other end is connected to the connecting block.

[0017] A second aspect of this application discloses a heat exchanger comprising multiple vacuum heat exchange tubes and a support frame; each vacuum heat exchange tube is provided with an integrated elliptical vacuum heat exchange tube sealing structure; the support frame is used to fix the vacuum heat exchange tubes.

[0018] According to the integrated elliptical vacuum heat exchanger sealing structure and heat exchanger of this application, the traditional heating and exhaust process is abandoned. By using negative pressure suction, high vacuum evacuation and filling can be directly carried out by external equipment. Since no heating is required, the working fluid will not flash or escape, thus ensuring precise control of the internal working fluid quality at the microscopic level. At the same time, it can minimize the amount of non-condensable gas residue inside, ensuring that the heat pipe has the advantages of high vacuum, fast start-up and accurate heat transfer, and significantly increasing the long-term reliable service life of the heat pipe from the traditional 1-3 years to 10-20 years.

[0019] To address the problem of intergranular leakage caused by rough welding and incomplete sealing of weld joints in traditional processes, the tail end of this application is integrally fused by thermal fusion sealing. This weld-free, brazing filler metal-structured fusion seal has extremely high mechanical strength and stress fatigue life compared to traditional split welded ends. It can adapt well to various harsh external operating environments and fundamentally eliminate the hidden danger of gas leakage at the end.

[0020] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0021] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0022] Figure 1 This is a schematic diagram of an integrated elliptical vacuum heat exchange tube sealing structure according to an embodiment of this application;

[0023] Figure 2This is a schematic diagram of an integrated elliptical vacuum heat exchange tube sealing structure according to another embodiment of this application;

[0024] Figure 3 This is a schematic diagram of the structure of the indicating device according to this application;

[0025] Figure 4 This is a schematic diagram of the internal structure of the indicating device according to this application;

[0026] Figure 5 This is a structural schematic diagram of the valve cap according to this application;

[0027] Figure 6 This is a structural schematic diagram of the sealing valve according to this application;

[0028] As shown in the figure:

[0029] 100. Tube body; 200. Tail end; 300. Head end; 400. Suction tube; 500. Nozzle cap; 501. Valve seat; 5011. Cylindrical cavity; 5012. Contraction cavity; 5013. Exhaust port; 5014. Shoulder; 600. Quick-release female connector; 700. Indicator; 710. Pointer; 720. Drive structure; 721. Push rod; 722. Engaging gear; 723. Gear; 730. Sealing valve; 731. Sliding part; 7311. Vent; 732. Valve body; 733. Sealing ring; 734. Extension rod; 735. Connecting block; 740. Temperature memory spring. Detailed Implementation

[0030] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0031] The integrated elliptical vacuum heat exchanger tube sealing structure of this application embodiment will be described below with reference to the accompanying drawings.

[0032] like Figure 1 As shown, the integrated elliptical vacuum heat exchanger tube sealing structure of this application embodiment may include a tube body 100, a suction tube 400, and a nozzle cap 500.

[0033] The tube body 100 has an elliptical axial cross-section, including a tail end 200 formed by heat fusion sealing and a radially contracting and outwardly extending head end 300 to form a chamber for containing the heat exchange medium. The suction pipe 400 is connected to the head end 300, and a straight suction channel is formed inside the suction pipe 400 to communicate with the chamber, which is used to discharge the gas in the chamber by negative pressure suction. The nozzle cap 500 is set at the opening of the suction pipe 400 (for example, the nozzle cap 500 can be connected to the opening of the suction pipe 400 by means of rigid fastening with threaded pairs, interference fit or end face sealing and pressing), which is used to seal the chamber after the suction is completed.

[0034] It should be noted that the elliptical cross-section tube 100 is suitable for cross-flow heat exchange scenarios of dusty flue gas in coal-fired power plants. Compared with a circular tube of the same cross-sectional area, it can improve the external convection heat exchange efficiency, reduce the leeward vortex area to reduce ash accumulation, and reduce the particle erosion wear rate. At the same time, it can optimize the spatial arrangement density, resulting in a better heat exchange efficiency ratio, and work together with the integrated sealing structure to improve the long-term reliability of the equipment.

[0035] To ensure the stability of the continuous forming process, the tube body 100, tail end 200, head end 300 and suction tube 400 are all made of the same metal material (for example, fine rolled steel with a carbon content of ≤0.25% can be used).

[0036] It should be noted that the axial cross-section of the tube body 100 can be circular or elliptical, and can also be adjusted according to the actual installation space and heat exchange requirements; the tube body 100 can be made of a base material that meets industrial-grade standards, such as a metal base material with a carbon content of no more than 0.25%. The base material is degreased and passivated, and can adapt to the harsh operating environment of dust, corrosion and high temperature alternation, such as waste heat recovery of flue gas in coal-fired power plants.

[0037] The tail end 200 is a closed end cap with a completely continuous metallographic structure formed by the bottom end of the tube body 100 through heat fusion shrinking, flattening and solidification without solder. During the encapsulation process of the tail end 200, the metal substrate at the bottom end of the tube shell is melted by high-pressure fusion sealing process using high-temperature heat fusion. After reaching the preset high-temperature heat fusion state, the bottom end of the tube body 100 is integrated by heat fusion shrinking and flattening until the molten metal is completely closed and converged under pressure and cooled and solidified. The entire forming process is the self-dissolution and solidification of the substrate itself, eliminating the conventional welding seal and the introduction of external solder, and achieving the best non-welding encapsulation state.

[0038] The sealed head, formed by solidification through a fusion sealing process, is structurally integrated with the tube body 100 into a seamless rigid whole. Microscopically, it exhibits a completely continuous, single-element metallographic structure without heterogeneous grain boundary barriers. By completely eliminating the weld joint surface of the separate welding process, this structure eliminates the risk of intergranular leakage and intergranular corrosion that are easily caused by the rough production process and lack of quality control in traditional heat pipes. This weld-free, one-piece formed sealed head has extremely high metallographic density, eliminates weak residual stress areas and material degradation blind spots, and can effectively resist the high-frequency stress generated by the vaporization and condensation cycle of the working fluid in the chamber.

[0039] This high-rigidity, high-quality homogeneous closed tail end 200 gives its overall structure and quality extremely high stability and reliability, enabling it to adapt well to various harsh operating environments such as industrial boilers or low-temperature economizers in coal-fired power plants. When facing cross-flow industrial flue gas with strong scouring, drastic alternating temperature differences, and high-frequency impact of high-velocity hard particles, the weld-free integrated tail end 200 has extremely strong resistance to stress creep and fatigue peeling, thereby effectively blocking the path for external non-condensable gases to permeate into the chamber.

[0040] Understandably, conventional traditional heating and exhaust methods can only achieve... The low vacuum level of Pa is due to the fact that this process relies on the working fluid vapor to entrain and remove air. Limited by the principle of gas-liquid balance, complete venting cannot be achieved. However, this application uses a suction method (e.g., an external molecular pump or negative pressure suction pump to evacuate the chamber), which can achieve a lower vacuum level. The high vacuum of Pa can completely remove most of the gas inside the tube, creating the optimal environment for the phase change of the working fluid.

[0041] The residual air, water vapor, and other non-condensable gases inside the pipe are the root cause of the performance degradation of the heat pipe. These gases will accumulate at the cold end during operation to form airlocks, blocking the heat transfer path. The residual gas content in the traditional heating exhaust method is usually high (e.g., above 5%), while this application can control the residual gas content to below 0.1% by using the air extraction method, thereby avoiding the airlock problem at its source and solving the problem of rapid thermal performance degradation caused by the heating exhaust method.

[0042] In addition, due to the large initial residual gas volume in traditional heating exhaust methods, the thermal resistance usually increases significantly after one year of operation, and the heat exchange efficiency drops sharply after two to three years. However, in this application, due to the extremely low initial residual gas volume and the combination of a highly reliable sealing structure, the thermal resistance can be maintained with small fluctuations over a 10-20 year lifespan, and the performance is stable over a long period of time, meeting the requirements for long-term continuous operation in industrial applications. Moreover, traditional heating exhaust methods are only suitable for working fluids such as low-purity water and ethanol, and cannot be compatible with working fluids such as ammonia and acetone that require high vacuum, thus limiting the applicable scenarios. The suction method used in this application can be compatible with a variety of working fluids such as water, ammonia, acetone, and liquid metals, and is suitable for high-requirement scenarios such as aerospace and nuclear power.

[0043] Furthermore, the welded sealing structure used in traditional heating and exhaust methods is prone to defects such as weld porosity and intergranular corrosion, and usually leaks and fails within 1-3 years. It is only suitable for scenarios with low reliability requirements, such as consumer electronics and residential heating. In contrast, this application adopts a fusion sealing process, which has high sealing reliability and a lifespan of 10-20 years. It can be applied to high-end fields such as aerospace, nuclear power, and precision instruments, and is particularly suitable for industrial-grade heat exchange scenarios that require long-term continuous operation, such as low-temperature economizers in coal-fired power plants and industrial waste heat recovery.

[0044] Therefore, the integrated elliptical vacuum heat exchanger tube sealing structure of this application successfully solves the problems of poor performance, short life and easy failure of traditional heating and exhaust methods, and has significant economic and social benefits.

[0045] In one embodiment of this application, the tail end 200 is a closed end cap in the shape of an arc or a plane.

[0046] It should be noted that when the tail end is closed with a 200 arc-shaped end cap, its end face has a smooth arc transition structure. This structure has a wide forming process window, low requirements for mold alignment, high production efficiency, and is suitable for mass continuous industrial forming. In terms of fluid dynamics, the smooth arc surface can follow the direction of crossflow flue gas and smoothly guide the flow, significantly reducing tube bundle resistance and mitigating local scouring wear. It can be widely used in conventional low-pressure or atmospheric-pressure industrial waste heat recovery scenarios such as low-temperature economizers in coal-fired power plants and air-source heat exchangers.

[0047] When the tail end 200 is a flat closed end cap, its end face is a flat plane, and the edge is connected to the seamless side wall of the tube body 100 through a rounded chamfer transition. The process control is simple and stable, the axial dimension of the product is very consistent, and it is easy to carry out large-scale standardized production.

[0048] In one embodiment of this application, such as Figure 2 As shown, the nozzle cap 500 is equipped with a quick-release female connector 600 for detachable connection with the quick-release male connector of an external negative pressure suction device. The quick-release female connector 600 has a built-in self-sealing valve core, which can automatically cut off the flow channel after the male connector is pulled out to achieve a leak-free seal.

[0049] It should be noted that, thanks to the quick-release female connector 600, when vacuum filling is required, the operator only needs to insert the quick-release male connector of the external device directly into the quick-release female connector 600 for automatic locking and quick connection. This quick-connect method not only saves time and effort and greatly improves production efficiency, but also provides excellent rigidity and airtightness.

[0050] Because the quick-release female connector 600 has a built-in self-sealing valve core (such as a spring-loaded valve core), when the male connector of the external device is fully inserted into the quick-release female connector 600 and locked, the internal pin of the male connector will automatically push the self-sealing valve core inward. At this time, the valve core opens, and the internal chamber of the suction tube 400 and the tube body 100 is connected to the external vacuum pump, and vacuum extraction begins. After filling is completed, the external male connector is pulled out. At the moment the external pin push is lost, the self-sealing valve core rebounds under the action of the internal return spring and the pressure difference between the inside and outside of the tube, realizing the automatic instantaneous closure of the flow channel.

[0051] Understandably, the quick-release female connector 600 fundamentally solves the gas backflow problem that exists in traditional heating and venting methods and ordinary gas nozzle cap 500 sealing, ensuring the stable maintenance of high vacuum inside the tube.

[0052] In one embodiment of this application, such as Figures 3 to 6 As shown, the valve cap 500 is provided with an indicator 700, which includes a pointer 710, a drive structure 720, a sealing valve 730, and a temperature memory spring 740.

[0053] The nozzle cap 500 has a retractable valve seat 501 inside. The sealing valve 730 is axially movable and is disposed in the valve seat 501, forming a separable airtight seal with the valve seat 501. One end of the temperature memory spring 740 is connected to the sealing valve 730, and the other end is connected to the valve seat 501. The pointer 710 is rotatably disposed on the outer dial of the nozzle cap 500. The dial has at least two scale areas, normal and fault, corresponding to the rotation range of the pointer 710.

[0054] The power input end of the drive structure 720 is connected to the sealing valve 730, and the power output end is connected to the pointer 710, so that when the sealing valve 730 is displaced, the pointer 710 is driven to rotate through the drive structure 720.

[0055] For clarity, in the embodiments of this application, the drive structure 720 includes a push rod 721, a sector tooth 722, and a gear 723.

[0056] The gear 723 is disposed inside the air nozzle cap 500 and is coaxially disposed with the rotating end of the pointer 710. The sector tooth 722 is rotatably disposed inside the air nozzle cap 500. The sector tooth 722 includes a concentric arc-shaped tooth portion and a rotating portion. The arc-shaped tooth portion meshes with the gear 723. One end of the push rod 721 is rotatably connected to the sealing valve 730, and the other end is eccentrically pivotally connected to the rotating portion.

[0057] For clarity, in the embodiments of this application, the valve seat 501 includes an axially connected cylindrical cavity 5011 and a contraction cavity 5012.

[0058] The small-diameter end of the contraction chamber 5012 forms an exhaust port 5013 that communicates with the suction tube 400. The outer edge of the exhaust port 5013 is provided with a shoulder 5014. One end of the temperature memory spring 740 is connected to the shoulder 5014, and the other end is connected to the sealing valve 730.

[0059] For clarity, in the embodiments of this application, the sealing valve 730 includes a sliding part 731, a valve body 732, a sealing ring 733, an extension rod 734, and a connecting block 735.

[0060] The sliding part 731 is embedded and slides within the cylindrical cavity 5011, and a vent 7311 is provided on the side of the sliding part 731. A hemispherical valve body 732 is disposed on the sliding part 731. A sealing ring 733 is embedded outside the valve body 732 and selectively and airtightly fits against the inner wall of the contraction cavity 5012. One end of the extension rod 734 is connected to the valve body 732, and the other end passes through the exhaust port 5013 and extends toward one side of the suction tube 400. A connecting block 735 is disposed on the extension end of the extension rod 734. A temperature memory spring 740 is sleeved on the extension rod 734, and one end is connected to the shoulder 5014, and the other end is connected to the connecting block 735. The temperature memory spring 740 is a nickel-titanium alloy shape memory spring, and its phase change temperature is set to 60℃-80℃, which can be adjusted according to the actual working conditions.

[0061] The temperature memory spring 740 is configured to change the magnitude of the inward pulling force according to the temperature change of the head end 300, so as to control the displacement of the valve body 732.

[0062] When the heat exchange tube is in a leak-free normal operating state, the temperature at the first end 300 is higher than the phase transformation temperature of the temperature memory spring 740. The temperature memory spring 740 undergoes an austenitic phase transformation, and the resulting tension is greater than the first resistance, so as to press the valve body 732 into the contraction chamber 5012 and maintain a sealed fit. The first resistance includes the sum of the outward thrust generated by the positive pressure of the working fluid vaporization in the tube on the valve body 732 and the mechanical resistance.

[0063] When a leak occurs during the operation of the heat exchange tube, the temperature at the first end 300 drops below the phase change temperature. The temperature memory spring 740 undergoes a reverse phase change, reducing its tension. Furthermore, the positive pressure of the residual air inside the tube after the leak generates an outward thrust on the valve body 732 that is greater than the second resistance, thus pushing the valve body 732 outward and releasing the sealing fit. The second resistance includes the sum of the tension of the temperature memory spring 740 and the mechanical resistance.

[0064] It should be noted that under normal operating conditions without leakage, the heat exchange tube operates normally. The temperature at the first end of 300°C is higher than the phase change temperature of the temperature memory spring 740. The working fluid undergoes normal phase change circulation, and the pressure inside the tube becomes positive pressure as the temperature rises. At this time, the temperature memory spring 740 undergoes an austenitic phase change, increasing the tension. This tension is greater than the first resistance (the first resistance includes the outward thrust of the working fluid vaporization positive pressure on the valve body 732 and mechanical resistance). As a result, the temperature memory spring 740 presses the valve body 732 tightly into the contraction chamber 5012, keeping it in a sealed position. No matter how much the positive pressure inside the tube increases, the valve body 732 will not be displaced. At this time, the pointer 710 always points stably to the normal scale range, completely unaffected by temperature and pressure fluctuations under normal operating conditions, and there is no possibility of false alarms.

[0065] When any form of leakage occurs in the heat pipe (external gas enters or internal working fluid leaks out), non-condensable gases accumulate to form a gas lock or the working fluid is lost, preventing steam from reaching the first end 300 to condense and release heat. The first end 300 loses its heat source. At this time, due to the heat exchange of the cold source, the temperature drops below the phase change temperature, and the temperature memory spring 740 undergoes a reverse phase change. At this time, the tension decreases rapidly. However, since there is still a residual positive pressure, the positive pressure at this time exerts a greater outward thrust on the valve body 732 than the second resistance (the second resistance includes the tension of the temperature memory spring 740 and the mechanical resistance). This causes the valve body 732 to be pushed outward, which drives the sector tooth 722 to rotate through the push rod 721, thereby driving the gear 723 and the pointer 710 to rotate. Finally, the pointer 710 points to the fault scale area.

[0066] It should be noted that conventional pressure gauges are completely different from the indicating device 700 in this application. Conventional pressure gauges can only read a single absolute pressure value, completely severing the inherent characteristics of heat pipe temperature and pressure. When coal-fired power plants are deeply shaving off peak loads and flue gas temperature fluctuates, the saturated vapor pressure of the working fluid in the pipe will rise and fall naturally in sync with the temperature. Similarly, if the pipe body 100 leaks and fails, it will also cause pressure changes. Therefore, conventional instruments cannot distinguish between pressure changes caused by normal operating condition fluctuations and leak failures. They will misjudge normal low loads as leak failures and will also miss faults where the initial pressure of a leak is still within the normal range, thus losing their value for inspection guidance.

[0067] This application uses the phase change characteristics of the temperature memory spring 740 as the judgment criterion. An alarm will only be triggered when both the residual positive pressure in the pipe and the cold end temperature drop below the phase change threshold are met simultaneously. Under normal operating conditions, no matter how the pressure fluctuates with the load, as long as the heat transfer cycle is normal, the cold end temperature will always be higher than the phase change point, and the temperature memory spring 740 will firmly lock the valve body 732. An alarm will only be triggered when a leak actually occurs, causing heat transfer failure and rapid cooling of the cold end.

[0068] A heat exchanger according to an embodiment of this application will now be described with reference to the accompanying drawings.

[0069] A heat exchanger includes multiple vacuum heat exchange tubes and a support frame; the vacuum heat exchange tubes are provided with an integrated elliptical vacuum heat exchange tube sealing structure; the support frame is used to fix the vacuum heat exchange tubes.

[0070] In summary, the integrated elliptical vacuum heat exchanger tube sealing structure and heat exchanger of this application abandon the traditional heating and exhaust process. By using negative pressure suction, high vacuum evacuation and filling can be directly implemented through external equipment. Since no heating is required, the working fluid will not flash or escape, thus ensuring precise control of the internal working fluid quality at the microscopic level. At the same time, it can minimize the amount of non-condensable gas residue inside, ensuring that the heat pipe has the advantages of high vacuum, fast start-up, and accurate heat transfer, and significantly increasing the long-term reliable service life of the heat pipe from the traditional 1-3 years to 10-20 years.

[0071] To address the problem of intergranular leakage caused by rough welding and incomplete sealing of weld joints in traditional processes, the tail end 200 of this application is integrally fused and formed by thermal fusion sealing. This weld-free, brazing filler metal-structured fusion seal has extremely high mechanical strength and stress fatigue life compared to traditional split welded ends. It can adapt well to various harsh external operating environments and fundamentally eliminate the hidden danger of gas leakage at the end.

[0072] In the description of this specification, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0073] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0074] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A one-piece elliptical vacuum heat exchanger tube sealing structure, characterized in that, include: The tube body (100) has an elliptical axial cross section and includes a tail end (200) integrally welded by heat fusion sealing and a head end (300) that radially contracts and extends outward to form a chamber for containing the heat exchange medium. A suction tube (400) is connected to the head end (300) and is used to discharge the gas in the chamber by negative pressure suction. An air nozzle cap (500) is provided at the opening of the suction tube (400) and is used to seal the chamber after the air is drawn.

2. The integrated elliptical vacuum heat exchanger tube sealing structure according to claim 1, characterized in that, The tail end (200) is a closed end cap in the shape of an arc or a plane.

3. The integrated elliptical vacuum heat exchanger tube sealing structure according to claim 1, characterized in that, The suction tube (400) forms a straight suction channel that communicates with the chamber.

4. The integrated elliptical vacuum heat exchanger tube sealing structure according to claim 1, characterized in that, The nozzle cap (500) is provided with a quick-release female connector (600) for detachable connection with the quick-release male connector of an external negative pressure suction device, and the quick-release female connector (600) has a self-sealing valve core built in.

5. The integrated elliptical vacuum heat exchanger tube sealing structure according to claim 1, characterized in that, The tube body (100), the tail end (200), the head end (300), and the suction tube (400) are all made of the same metal material.

6. The integrated elliptical vacuum heat exchanger tube sealing structure according to claim 1, characterized in that, The valve cap (500) is provided with an indicator (700), which includes a pointer (710), a drive structure (720), a sealing valve (730), and a temperature memory spring (740). The valve cap (500) is provided with a retractable valve seat (501), and the sealing valve (730) is axially movable and disposed in the valve seat (501), and forms a separable airtight seal with the valve seat (501). One end of the temperature memory spring (740) is connected to the sealing valve (730), and the other end is connected to the valve seat (501); The pointer (710) is rotatably mounted on the outer dial of the valve cap (500); The power input end of the drive structure (720) is connected to the sealing valve (730), and the power output end is connected to the pointer (710), so that when the sealing valve (730) is displaced, the drive structure (720) drives the pointer (710) to rotate.

7. The integrated elliptical vacuum heat exchanger tube sealing structure according to claim 6, characterized in that, The drive structure (720) includes a push rod (721), a sector tooth (722), and a gear (723), wherein, The gear (723) is disposed inside the air nozzle cap (500) and is coaxially disposed with the rotating end of the pointer (710); The sector tooth (722) is rotatably disposed within the air nozzle cap (500). The sector tooth (722) includes a concentric arc-shaped tooth portion and a rotating portion, wherein the arc-shaped tooth portion meshes with the gear (723). One end of the push rod (721) is rotatably connected to the sealing valve (730), and the other end is eccentrically pivotally connected to the rotating part.

8. The integrated elliptical vacuum heat exchanger tube sealing structure according to claim 6, characterized in that, The valve seat (501) includes an axially connected cylindrical cavity (5011) and a contraction cavity (5012). The small-diameter end of the contraction cavity (5012) forms an exhaust port (5013) that communicates with the suction tube (400), and the outer edge of the exhaust port (5013) is provided with a shoulder (5014). One end of the temperature memory spring (740) is connected to the shoulder (5014), and the other end is connected to the sealing valve (730).

9. The integrated elliptical vacuum heat exchanger tube sealing structure according to claim 8, characterized in that, The sealing valve (730) includes a sliding part (731), a valve body (732), a sealing ring (733), an extension rod (734), and a connecting block (735), wherein, The sliding part (731) is embedded and slides within the cylindrical cavity (5011), and a vent (7311) is provided on the side of the sliding part (731). The hemispherical valve body (732) is disposed on the sliding part (731); The sealing ring (733) is embedded outside the valve body (732) and selectively and airtightly fits the inner wall of the contraction cavity (5012); One end of the extension rod (734) is connected to the valve body (732), and the other end passes through the exhaust port (5013) and extends toward one side of the suction tube (400). The connecting block (735) is disposed on the extension end of the extension rod (734); The temperature memory spring (740) is sleeved on the extension rod (734), with one end connected to the shoulder (5014) and the other end connected to the connecting block (735).

10. A heat exchanger, characterized in that, Includes multiple vacuum heat exchange tubes and a support frame; The vacuum heat exchange tube is provided with an integrated elliptical vacuum heat exchange tube sealing structure as described in any one of claims 1-9; The support frame is used to fix the vacuum heat exchange tube.

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