Threaded sealing structure of aluminum alloy gas storage tank and assembling method thereof

Abstract

The invention belongs to the technical field of sealing, and particularly relates to an aluminum alloy gas storage tank thread sealing structure and an assembling method thereof. The threaded sealing structure of the aluminum alloy gas storage tank comprises an aluminum alloy air cylinder pipe seat, a sealing ring and a sealing ring, the stainless steel sealing sleeve is coaxially assembled in the mounting hole, an external thread matched with the internal thread is arranged on the outer wall of the stainless steel sealing sleeve, and the internal thread of the aluminum alloy air cylinder pipe seat is in a non-sealing pipe thread type; and the first high-temperature epoxy glue layer is cured and formed in a meshing gap between the internal thread of the aluminum alloy air cylinder pipe seat and the external thread of the stainless steel sealing sleeve to form structural bonding. According to the structure, through the combination design of the stainless steel sealing sleeve and the aluminum alloy air cylinder pipe base, the perfect combination of light weight and high strength characteristics is achieved. When the sealing structure is damaged due to long-term use, the first high-temperature epoxy glue layer can be softened through acetylene heating, and an old stainless steel sealing sleeve can be easily taken out and replaced with a new sleeve piece.

Description

Technical Field

[0001] This invention belongs to the field of sealing technology, specifically relating to a threaded sealing structure for an aluminum alloy gas storage tank and its assembly method. Background Technology

[0002] In existing technologies, the pipe seat connection of aluminum alloy storage tanks generally adopts a structural design that directly machines internal threads on the aluminum alloy substrate. This traditional solution has the following prominent technical defects in practical applications: Poor reliability of threaded structures: Due to the low hardness of aluminum alloy, the thread profile is prone to plastic deformation during repeated disassembly and assembly. Industry test data shows that when the number of disassembly and assembly cycles reaches more than 5, the failure probability of the threaded connection structure is as high as 30%, which seriously restricts the service life and maintenance cycle of the equipment.

[0003] The repair process is complex: when the threads are damaged, traditional repair methods require welding the tank body. However, aluminum alloy welding requires strict control of process parameters, and even slight carelessness can cause intergranular corrosion, leading to defects such as microcracks in the welded area, which in turn exacerbates structural safety hazards.

[0004] Severe economic losses: For severely damaged threaded structures, the entire storage tank often needs to be replaced. Taking a common 500L industrial storage tank as an example, the direct economic loss caused by a single scrapping can reach tens of thousands of yuan, while also incurring additional production downtime losses and environmental treatment costs. Summary of the Invention

[0005] One of the objectives of this invention is to provide a novel threaded sealing structure for aluminum alloy gas storage tanks, in order to solve or improve at least one technical problem existing in related technologies.

[0006] The second objective of this invention is to provide an equipment method for the above-mentioned aluminum alloy gas tank threaded sealing structure.

[0007] On one hand, embodiments of the present invention provide a threaded sealing structure for an aluminum alloy gas storage tank, comprising: an aluminum alloy air cylinder seat having an internally threaded mounting hole; a stainless steel sealing sleeve coaxially assembled within the mounting hole, the outer wall of the stainless steel sealing sleeve having an external thread that mates with the internal thread, and the internal thread of the aluminum alloy air cylinder seat being a non-sealing pipe thread; and a first high-temperature epoxy adhesive layer cured and formed within the meshing gap between the internal thread of the aluminum alloy air cylinder seat and the external thread of the stainless steel sealing sleeve, forming a structural bond. This structure, through the combined design of the stainless steel sealing sleeve and the aluminum alloy air cylinder seat, achieves a perfect combination of lightweight and high-strength characteristics. The choice of a non-sealing pipe thread provides greater assembly tolerance and significantly reduces the requirements for precision machining. The curing and forming of the first high-temperature epoxy adhesive layer within the thread meshing gap not only fills the microscopic gaps but also forms a permanent structural bond, effectively preventing media leakage. This design is particularly suitable for operating conditions requiring frequent disassembly and assembly, significantly improving the overall reliability of the connection structure while ensuring sealing performance. When the sealing structure is damaged due to long-term use, the first high-temperature epoxy adhesive layer can be softened by acetylene heating, allowing the old stainless steel sealing sleeve to be easily removed and replaced with a new one. The entire process eliminates the need for welding or complete replacement of the tank body, avoiding the risk of thermal damage to the aluminum alloy substrate caused by high-temperature welding and significantly reducing maintenance costs and downtime losses. This replaceable design extends the service life of the tank many times over while reducing resource waste, offering significant economic and environmental advantages.

[0008] As an improvement to the aforementioned threaded sealing structure of the aluminum alloy gas storage tank, the stainless steel sealing sleeve includes an integrally formed interference fit portion and a threaded connection portion, wherein: the outer diameter of the interference fit portion is larger than the outer diameter of the threaded connection portion, forming a stepped tubular structure; a second high-temperature epoxy adhesive layer is filled between the axial end face of the interference fit portion and the end face of the aluminum alloy air cylinder pipe seat. The stepped tubular structure design creates a dual sealing mechanism: the interference fit portion provides an initial mechanical seal, while the second high-temperature epoxy adhesive layer forms a secondary chemical seal. This combined sealing method significantly improves sealing stability under pressure fluctuation conditions. When the overall structure is subjected to axial loads, it can achieve a reasonable stress distribution through a stepped transition, avoiding seal failure caused by localized stress concentration.

[0009] As an improvement to the aforementioned threaded sealing structure of the aluminum alloy gas storage tank, an annular sealing groove is provided on the end face of the aluminum alloy air cylinder pipe seat, and the annular sealing groove is filled with the second high-temperature epoxy adhesive layer. The design of the annular sealing groove allows the second high-temperature epoxy adhesive layer to form a defined sealing ring, ensuring that the adhesive maintains its preset geometric shape during curing. This structure effectively prevents adhesive extrusion or uneven distribution during assembly, ensuring the integrity of the sealing interface. The geometric constraint of the sealing groove also enhances the shear resistance of the cured adhesive layer, enabling the sealing structure to better withstand alternating loads. This design is particularly suitable for operating conditions involving vibration or thermal cycling.

[0010] As an improvement to the aforementioned threaded sealing structure of the aluminum alloy gas tank, an annular conical groove is provided at the end of the threaded connection away from the interference fit. This annular conical groove is filled with the first high-temperature epoxy adhesive layer. The design of the annular conical groove creates a storage space for the adhesive, guiding it to flow evenly towards the threaded engagement area during assembly. The conical structure facilitates air removal, preventing the formation of air bubbles. This design also forms an additional sealing ring, establishing a leak-proof barrier at the end of the threaded connection. After the adhesive in the groove cures, it effectively absorbs vibration energy, reducing the risk of fretting wear at the threaded connection and extending the service life of the sealing structure.

[0011] As an improvement to the aforementioned threaded sealing structure of the aluminum alloy gas tank, an annular stress relief groove is provided at the end of the threaded connection near the interference fit. The annular stress relief groove alters the stress transmission path, forming an elastic buffer zone in the critical transition area of ​​the threaded connection. This design effectively alleviates interfacial stress caused by differences in thermal expansion coefficients, preventing microcracks in the adhesive layer. The groove structure also increases the adhesive wetting area, significantly improving the interfacial bonding strength. Under dynamic loads, this area can absorb energy through moderate elastic deformation, maintaining the integrity of the sealing interface.

[0012] As an improvement to the aforementioned threaded sealing structure of the aluminum alloy gas tank, at least one of the first and second high-temperature epoxy adhesive layers is an epoxy resin adhesive with a temperature resistance range of -40℃ to 180℃. The use of a wide-temperature-range epoxy resin adhesive allows the sealing structure to adapt to the working requirements of extreme temperature environments. This material maintains good toughness at low temperatures, avoiding brittle failure; and maintains sufficient bond strength at high temperatures, preventing creep-induced degradation of sealing performance. The unique formulation of the modified epoxy resin also resists the erosion of various chemical media, ensuring stable sealing performance in corrosive environments over a long period, significantly expanding the product's applicability.

[0013] As an improvement to the aforementioned aluminum alloy gas tank threaded sealing structure, the inner thread surface of the aluminum alloy air cylinder seat undergoes anodizing treatment to form an anodized layer. The dense oxide layer formed on the aluminum alloy thread surface by anodizing effectively prevents direct contact between the base metal and the environmental medium, significantly improving corrosion resistance. This treatment also significantly increases surface hardness and wear resistance, ensuring the threads maintain excellent geometric accuracy during repeated assembly and disassembly. The porous nature of the oxide layer provides excellent mechanical anchoring points for the adhesive, greatly enhancing the interfacial bonding strength and ensuring the long-term reliability of the sealing structure.

[0014] As an improvement to the aforementioned aluminum alloy gas tank threaded sealing structure, the outer thread surface of the stainless steel sealing sleeve is coated with a silane coupling agent. The coating of the silane coupling agent establishes a molecular-level bridge between the metal and the polymer material, achieving a gradient transition from rigid metal to a flexible adhesive layer. This treatment not only improves the initial bond strength but, more importantly, maintains the long-term stability of the interface under humid and hot aging conditions. The monolayer formed by the oriented alignment of the coupling agent molecules effectively prevents the penetration of water molecules, avoiding common interfacial moisture erosion problems and significantly extending the service life of the sealing structure.

[0015] As an improvement to the aforementioned aluminum alloy gas tank threaded sealing structure, the anodized layer is a hard anodized layer. The surface of the hard anodized layer is impregnated with polytetrafluoroethylene dispersion and dried to form a friction-reducing and wear-resistant composite coating.

[0016] As an improvement to the aforementioned aluminum alloy gas tank threaded sealing structure, at least one surface acoustic wave sensor is embedded in the interference fit end face of the stainless steel sealing sleeve, and the antenna of the surface acoustic wave sensor extends into the second high-temperature epoxy layer.

[0017] As an improvement to the aforementioned aluminum alloy gas tank threaded sealing structure, at least one of the first high-temperature epoxy adhesive layer and the second high-temperature epoxy adhesive layer is doped with thermochromic pigment particles.

[0018] On the other hand, embodiments of the present invention provide a method for assembling a threaded sealing structure for an aluminum alloy gas storage tank, comprising the following steps: The internal threads of the aluminum alloy air cylinder pipe seat are anodized. A silane coupling agent is coated on the external thread surface of the stainless steel sealing sleeve; Epoxy resin adhesive is uniformly applied to the inner thread surface of the aluminum alloy air cylinder pipe seat and the outer thread surface of the stainless steel sealing sleeve. Screw the stainless steel sealing sleeve into the mounting hole of the aluminum alloy air cylinder pipe seat to the set torque value, and let it stand to cure.

[0019] This assembly method ensures optimal performance of each functional layer through systematic surface treatment and precise process control. Anodizing provides durable protection for the substrate, silane coupling agent coating optimizes interfacial properties, and step-by-step adhesive application guarantees perfect adhesive distribution. Torque-controlled assembly ensures that the preload of threaded connections is within the optimal range, and static curing allows for the full development of material properties. This standardized assembly process guarantees consistent product performance and significantly reduces quality fluctuations during manufacturing.

[0020] As an improvement to the aforementioned method for assembling the threaded sealing structure of the aluminum alloy gas tank, the set torque value is 5-8 N·m, and the curing time is 24 hours. Precise torque control ensures that the threaded connection receives appropriate initial preload, avoiding both stress concentration caused by excessive tightness and insufficient sealing caused by excessive looseness. The optimized curing time ensures that the adhesive completes a full cross-linking reaction, achieving the designed mechanical properties. This combination of process parameters enables the product to achieve an optimal balance of overall performance, including key indicators such as sealing reliability, mechanical strength, and durability.

[0021] The aluminum alloy gas tank threaded sealing structure of this invention achieves an optimized combination of material properties through a composite structure design of a stainless steel sealing sleeve and an aluminum alloy air cylinder pipe seat: it retains the lightweight advantage of aluminum alloy while significantly improving the mechanical strength of the overall structure through stainless steel components. The use of a non-sealing pipe thread not only expands the assembly tolerance range but also significantly reduces the machining accuracy requirements, effectively controlling production costs. The specially designed first high-temperature epoxy adhesive layer, after curing within the thread engagement gap, not only fills the microscopic gaps but also forms a durable chemical-mechanical dual bonding system, providing reliable protection for media sealing. This structure is particularly suitable for operating environments requiring regular maintenance, significantly enhancing the overall stability and service life of the connection structure while ensuring excellent sealing performance. When the sealing component experiences performance degradation due to long-term use, the old sealing sleeve can be easily removed and replaced with a new component simply by softening the first high-temperature epoxy adhesive layer with acetylene heating. This avoids the high-temperature welding work required for the tank body in traditional maintenance methods, fundamentally eliminating the risk of intergranular corrosion of aluminum alloy caused by the heat-affected zone of welding. It also keeps maintenance costs low and significantly reduces equipment downtime. This modular and replaceable design not only significantly extends the service life of the tank but also embodies a green and environmentally friendly design philosophy by reducing material waste, demonstrating significant advantages in both economic benefits and sustainable development. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the threaded sealing structure of an aluminum alloy gas storage tank according to an embodiment of the present invention.

[0024] Figure 2 for Figure 1 A magnified schematic diagram of section I.

[0025] Figure 3 for Figure 1 A magnified schematic diagram of the structure at point II.

[0026] Figure 4 for Figure 1 A magnified schematic diagram of the structure at point III.

[0027] Figure 5 This is a schematic diagram of the structure of a stainless steel sealing sleeve according to an embodiment of the present invention.

[0028] Legend: 10. Aluminum alloy air cylinder pipe seat; 20. Stainless steel sealing sleeve; 21. Interference fit part; 22. Threaded connection part; 30. Annular sealing groove; 40. Annular conical groove; 50. Annular stress relief groove; Detailed Implementation

[0029] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," etc., indicating orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0030] Furthermore, 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 technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0031] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0032] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that they are in indirect contact through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "below" of the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0033] In the description of this specification, the references to "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 the present invention. 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.

[0034] like Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5As shown, this embodiment of the invention provides a threaded sealing structure for an aluminum alloy gas storage tank, comprising: an aluminum alloy air cylinder pipe seat 10, which has an mounting hole (not shown in the figure) with internal threads (not shown); a stainless steel sealing sleeve 20, coaxially assembled in the mounting hole, the outer wall of the stainless steel sealing sleeve 20 having external threads (not shown in the figure) that mate with the internal threads, and the internal threads of the aluminum alloy air cylinder pipe seat 10 being a non-sealing pipe thread type; and a first high-temperature epoxy adhesive layer (not shown in the figure), cured and formed in the meshing gap between the internal threads of the aluminum alloy air cylinder pipe seat 10 and the external threads of the stainless steel sealing sleeve 20, forming a structural bond. This structure, through the combined design of the stainless steel sealing sleeve 20 and the aluminum alloy air cylinder pipe seat 10, achieves a perfect combination of lightweight and high-strength characteristics. The choice of a non-sealing pipe thread type provides a larger assembly tolerance, significantly reducing the requirements for precision machining. The curing and forming of the first high-temperature epoxy adhesive layer in the thread meshing gap not only fills the microscopic gaps but also forms a permanent structural bond, effectively preventing media leakage. This design is particularly suitable for operating conditions requiring frequent disassembly and assembly, significantly improving the overall reliability of the connection structure while ensuring sealing performance. When the sealing structure is damaged due to long-term use, the first high-temperature epoxy adhesive layer can be softened by acetylene heating, allowing for easy removal of the old stainless steel sealing sleeve 20 and replacement with a new one. The entire process eliminates the need for welding or complete replacement of the tank body, avoiding the risk of thermal damage to the aluminum alloy substrate caused by high-temperature welding and significantly reducing maintenance costs and downtime losses. This replaceable design extends the service life of the tank many times over while reducing resource waste, offering outstanding economic benefits and environmental advantages.

[0035] In some embodiments of the present invention, the internal thread of the aluminum alloy air cylinder pipe seat 10 may be, but is not limited to, a metric fine thread (such as M48×1.5) conforming to GB / T196, and the external thread of the stainless steel sealing sleeve 20 may be, but is not limited to, a sealing fine thread (such as M48*1.5 sealing) conforming to GB / T196, and the internal thread of the stainless steel sealing sleeve 20 is a non-sealing pipe thread G thread, conforming to ISO228-1 requirements.

[0036] As described above, the aluminum alloy gas tank threaded sealing structure of this invention achieves an optimized combination of material properties through a composite structure design of a stainless steel sealing sleeve 20 and an aluminum alloy air cylinder pipe seat 10. It retains the lightweight advantages of aluminum alloy while significantly enhancing the overall mechanical strength of the structure through stainless steel components. The use of a non-sealing pipe thread not only expands the assembly tolerance range but also significantly reduces the machining accuracy requirements, effectively controlling production costs. The specially designed first high-temperature epoxy adhesive layer, after curing within the thread engagement gap, not only fills the microscopic gaps but also forms a durable chemical-mechanical dual bonding system, providing reliable protection for media sealing. This structure is particularly suitable for operating environments requiring regular maintenance, significantly enhancing the overall stability and service life of the connection structure while ensuring excellent sealing performance. When the sealing component experiences performance degradation due to long-term use, the old sealing sleeve can be easily removed and replaced with a new component simply by softening the first high-temperature epoxy adhesive layer with acetylene heating. This avoids the high-temperature welding work required for the tank body in traditional maintenance methods, fundamentally eliminating the risk of intergranular corrosion of aluminum alloy caused by the heat-affected zone of welding. Simultaneously, it keeps maintenance costs low and significantly reduces equipment downtime. This modular and replaceable design not only significantly extends the service life of the tank but also embodies a green and environmentally friendly design philosophy by reducing material waste, demonstrating significant advantages in both economic benefits and sustainable development. This invention is applicable to the storage and transportation of corrosive media at working pressures of 0-1 MPa.

[0037] In some embodiments of the present invention, the stainless steel sealing sleeve 20 includes an integrally formed interference fit portion 21 and a threaded connection portion 22, wherein: the outer diameter of the interference fit portion 21 is larger than the outer diameter of the threaded connection portion 22, forming a stepped tubular structure; a second high-temperature epoxy adhesive layer (not shown in the figure) is filled between the axial end face of the interference fit portion 21 and the end face of the aluminum alloy air cylinder pipe seat 10. The stepped tubular structure design creates a dual sealing mechanism: the interference fit portion 21 provides an initial mechanical seal, while the second high-temperature epoxy adhesive layer forms a secondary chemical seal. This combined sealing method significantly improves the sealing stability under pressure fluctuation conditions. When the overall structure is subjected to axial load, it can achieve a reasonable stress distribution through a stepped transition, avoiding seal failure caused by local stress concentration.

[0038] In some embodiments of the present invention, the inner bore of the stainless steel sealing sleeve 20 is provided with a tapered pipe thread or an NPT thread for connecting to an external pipeline, and the axis of the inner thread of the stainless steel sealing sleeve 20 and the axis of the outer thread of the external pipeline have a coaxiality tolerance of ≤0.05mm, ensuring the sealing reliability of the secondary connection. Specifically, the inner bore of the stainless steel sealing sleeve 20 is provided with a tapered pipe thread (such as NPT) or a metric tapered thread for connecting to an external pipeline. The machining accuracy of the inner thread of the stainless steel sealing sleeve 20 requires that the coaxiality tolerance between its axis and the axis of the outer thread of the stainless steel sealing sleeve be controlled within ≤0.05mm. This precise coaxiality design ensures that when the external pipeline is connected to the stainless steel sealing sleeve, no additional bending moment or stress will be generated due to axis deviation, thereby ensuring the sealing reliability and long-term stability of the secondary connection interface and avoiding the risk of leakage due to stress concentration.

[0039] In some embodiments of the present invention, an annular sealing groove 30 is provided on the end face of the aluminum alloy air cylinder pipe seat 10, and the annular sealing groove 30 is filled with the second high-temperature epoxy adhesive layer. The design of the annular sealing groove 30 enables the second high-temperature epoxy adhesive layer to form a defined sealing ring, ensuring that the adhesive maintains a preset geometric shape during the curing process. This structure effectively prevents the adhesive from being extruded or unevenly distributed during assembly, ensuring the integrity of the sealing interface. The geometric constraint of the sealing groove also enhances the shear resistance of the cured adhesive layer, enabling the sealing structure to better withstand alternating loads. This design is particularly suitable for operating conditions with vibration or thermal cycling. In some embodiments of the present invention, the annular sealing groove 30 is configured as a circular arc groove with a radius of 1 ± 0.2.

[0040] In some embodiments of the present invention, an annular conical groove 40 is provided at the end of the threaded connection portion 22 away from the interference fit portion 21, and the annular conical groove 40 is filled with the first high-temperature epoxy adhesive layer. The design of the annular conical groove 40 creates a storage space for the adhesive, guiding the adhesive to flow evenly to the threaded engagement area during assembly. The conical structure helps to expel air and avoid the formation of air bubble defects. This design also forms an additional sealing ring, establishing a leakage-proof barrier at the end of the threaded connection. After the adhesive in the groove cures, it can effectively absorb vibration energy, reduce the risk of fretting wear at the threaded connection, and extend the service life of the sealing structure.

[0041] In some embodiments of the present invention, an annular stress relief groove 50 is provided at one end of the threaded connection portion 22 near the interference fit portion 21. The annular stress relief groove 50 alters the stress transmission path, forming an elastic buffer zone in the critical transition area of ​​the threaded connection. This design effectively alleviates interfacial stress caused by differences in thermal expansion coefficients, preventing microcracks in the adhesive layer. The groove structure also increases the wetting area of ​​the adhesive, significantly improving the interfacial bonding strength. Under dynamic loads, this area can absorb energy through moderate elastic deformation, maintaining the integrity of the sealing interface. In some embodiments of the present invention, the annular stress relief groove 50 has a groove width of 2-3 mm and a depth of 1-1.5 mm.

[0042] In some embodiments of the present invention, the first high-temperature epoxy adhesive layer and / or the second high-temperature epoxy adhesive layer are epoxy resin adhesives with a temperature resistance range of -40°C to 180°C. The use of a wide-temperature-range epoxy resin adhesive enables the sealing structure to adapt to the working requirements of extreme temperature environments. This material maintains good toughness at low temperatures, avoiding brittle failure; and maintains sufficient bond strength at high temperatures, preventing creep-induced degradation of sealing performance. The unique formulation of the modified epoxy resin also resists the erosion of various chemical media, ensuring stable sealing performance over a long period in corrosive environments, significantly expanding the product's applicability.

[0043] In some embodiments of the present invention, the internal thread surface of the aluminum alloy air cylinder pipe seat 10 is anodized to form an anodized layer (not shown in the figure). The dense oxide layer formed on the surface of the aluminum alloy thread by anodizing effectively blocks direct contact between the base metal and the environmental medium, significantly improving corrosion resistance. This treatment also significantly increases surface hardness and wear resistance, allowing the thread to maintain good geometric accuracy during repeated assembly and disassembly. The porous nature of the oxide layer provides excellent mechanical anchoring points for adhesives, greatly enhancing the interfacial bonding strength and ensuring the long-term reliability of the sealing structure. In some embodiments of the present invention, the thickness of the anodized layer is 10-20 μm, and the surface hardness is ≥HV800.

[0044] In some embodiments of the present invention, the external thread surface of the stainless steel sealing sleeve 20 is coated with a silane coupling agent (not shown in the figure). The coating of the silane coupling agent establishes a molecular-level bridge between the metal and the polymer material, achieving a gradient transition from rigid metal to a flexible adhesive layer. This treatment not only improves the initial bond strength but, more importantly, maintains the long-term stability of the interface under humid and hot aging conditions. The monolayer formed by the oriented arrangement of coupling agent molecules effectively prevents the penetration of water molecules, avoiding common interfacial moisture erosion problems and significantly extending the service life of the sealing structure. In some embodiments of the present invention, the external thread surface of the stainless steel sealing sleeve 20 is pretreated with a silane coupling agent, with a pretreatment layer thickness of 0.5-2 μm, increasing the adhesive bonding strength by 40-50%.

[0045] In some embodiments of the present invention, the anodic oxide layer is a hard anodic oxide layer. The surface of this hard anodic oxide layer is impregnated with a polytetrafluoroethylene (PTFE) dispersion and dried to form a friction-reducing and wear-resistant composite coating. Specifically, the anodic oxide layer is a hard anodic oxide layer, and its surface is further impregnated with a polytetrafluoroethylene (PTFE) dispersion and dried to form a friction-reducing and wear-resistant composite coating. A simple anodic oxide layer has high hardness but is relatively brittle. After being composited with PTFE, the coefficient of friction on the aluminum alloy thread surface is significantly reduced, making the screwing in and out of the stainless steel sealing sleeve smoother, further reducing wear on the aluminum alloy threads during disassembly and assembly. This is particularly suitable for scenarios requiring repeated maintenance, greatly extending the lifespan of the air cylinder pipe seat body. Therefore, in at least one embodiment, this structure, by forming a PTFE composite coating, effectively reduces the coefficient of friction and wear rate of the threaded pair, significantly improving the smoothness of disassembly and assembly and the reusability of the stainless steel sealing sleeve, thereby significantly extending the service life of the aluminum alloy pipe seat body in frequent maintenance situations.

[0046] In some embodiments of the present invention, at least one surface acoustic wave (SAW) sensor (not shown in the figure) is embedded in the end face of the interference fit portion 21 of the stainless steel sealing sleeve 20, and the antenna of the SAW sensor extends into the second high-temperature epoxy adhesive layer. A SAW sensor is a sensor chip that can realize real-time online monitoring of temperature and pressure at the sealing interface. The operating status of the sealing structure can be obtained through a wireless reading device, enabling predictive maintenance, early detection of leakage or failure risks, and a high degree of intelligence. In this at least one embodiment, the structure achieves real-time wireless monitoring of the temperature and pressure of the sealing interface by integrating a SAW sensor, improving the status perception and fault early warning capabilities.

[0047] In some embodiments of the present invention, hollow glass microspheres with a particle size of 10-50 μm are uniformly dispersed in the first high-temperature epoxy adhesive layer, and the volume of the hollow glass microspheres accounts for 5%-15% of the total volume of the adhesive layer. This not only reduces the density of the adhesive layer, but also effectively absorbs the internal stress caused by thermal expansion and contraction through the elastic deformation of the microspheres, thereby improving the fatigue resistance of the adhesive layer under alternating loads. Specifically, the first high-temperature epoxy adhesive layer may be premixed with hollow glass microspheres with a particle size of 10-50 μm. These microspheres are uniformly dispersed in the epoxy resin system, and their volume percentage is controlled to be 5% to 15% of the total volume of the adhesive layer. The introduction of hollow glass microspheres can, on the one hand, slightly reduce the overall density of the cured adhesive layer, achieving lightweighting; on the other hand, and more importantly, these microspheres act as elastomers in the adhesive layer, and can undergo slight elastic deformation under the action of internal stress caused by external temperature changes or mechanical vibrations, thereby effectively absorbing and dissipating energy, significantly improving the fatigue resistance and durability of the adhesive layer under alternating loads.

[0048] In some embodiments of the present invention, at least one of the first high-temperature epoxy adhesive layer and the second high-temperature epoxy adhesive layer is doped with thermochromic pigment particles. The thermochromic pigment provides a low-cost, intuitive maintenance indication solution. When acetylene heating is used for maintenance, the color of the adhesive layer undergoes a significant reversible or irreversible change as the temperature rises (e.g., from pink to colorless). Operators can visually determine whether the heating is sufficient (the epoxy adhesive has softened), avoiding underheating or overheating, making maintenance operations more precise and safer. Therefore, in at least one embodiment, the thermochromic pigment provides a visual temperature indication during the maintenance heating process, effectively preventing underheating or overheating, and improving the safety and accuracy of maintenance operations.

[0049] In summary, the aluminum alloy gas tank threaded sealing structure of this invention achieves an optimized combination of material properties through a composite structure design of a stainless steel sealing sleeve 20 and an aluminum alloy air cylinder pipe seat 10: it retains the lightweight advantage of aluminum alloy while significantly improving the overall mechanical strength of the structure through stainless steel components. The use of a non-sealing pipe thread not only expands the assembly tolerance range but also significantly reduces the machining accuracy requirements, effectively controlling production costs. The specially designed first high-temperature epoxy adhesive layer, after curing within the thread engagement gap, not only fills the microscopic gaps but also forms a durable chemical-mechanical dual bonding system, providing reliable protection for media sealing. This structure is particularly suitable for operating environments requiring regular maintenance, significantly enhancing the overall stability and service life of the connection structure while ensuring excellent sealing performance. When the sealing component experiences performance degradation due to long-term use, the old sealing sleeve can be easily removed and replaced with a new component simply by softening the first high-temperature epoxy adhesive layer with acetylene heating. This avoids the high-temperature welding work required for the tank body in traditional maintenance methods, fundamentally eliminating the risk of intergranular corrosion of aluminum alloy caused by the heat-affected zone of welding. It also keeps maintenance costs low and significantly reduces equipment downtime. This modular and replaceable design not only significantly extends the service life of the tank but also embodies a green and environmentally friendly design philosophy by reducing material waste, demonstrating significant advantages in both economic benefits and sustainable development.

[0050] In some embodiments of the present invention, the present invention provides a method for assembling a threaded sealing structure for an aluminum alloy gas storage tank, comprising the following steps: The internal threads of the aluminum alloy air cylinder pipe seat 10 are anodized. A silane coupling agent is coated on the external thread surface of the stainless steel sealing sleeve 20; Epoxy resin adhesive is uniformly applied to the inner thread surface of the aluminum alloy air cylinder pipe seat 10 and the outer thread surface of the stainless steel sealing sleeve 20. Screw the stainless steel sealing sleeve 20 into the mounting hole of the aluminum alloy air cylinder pipe seat 10 to the set torque value, and let it stand to cure.

[0051] This assembly method ensures optimal performance of each functional layer through systematic surface treatment and precise process control. Anodizing provides durable protection for the substrate, silane coupling agent coating optimizes interfacial properties, and step-by-step adhesive application guarantees perfect adhesive distribution. Torque-controlled assembly ensures that the preload of threaded connections is within the optimal range, and static curing allows for the full development of material properties. This standardized assembly process guarantees consistent product performance and significantly reduces quality fluctuations during manufacturing.

[0052] In some embodiments of the invention, the set torque value is 5-8 N·m, and the curing time is 24 hours. Precise torque control ensures that the threaded connection receives appropriate initial preload, avoiding both stress concentration due to overtightening and insufficient sealing due to over-loosening. Optimized curing time ensures that the adhesive completes a full cross-linking reaction, achieving the designed mechanical properties. This combination of process parameters enables the product to achieve an optimal balance of overall performance, including key indicators such as sealing reliability, mechanical strength, and durability.

[0053] In some embodiments of the present invention, during the screwing in of the stainless steel sealing sleeve 20, ultrasonic vibration with a frequency of 20-40 kHz, an amplitude of 3-8 μm, and a duration of 5-15 seconds is applied to the outer wall of the aluminum alloy air cylinder tube seat 10. This step utilizes the vibration energy of the ultrasonic waves to promote the flow and filling of the epoxy adhesive within the thread gap, eliminate micro-air bubbles, ensure a continuous and defect-free adhesive layer, and simultaneously initiate the pre-curing of the adhesive at low temperatures, thereby improving initial strength. Specifically, optionally, during the process of screwing the stainless steel sealing sleeve 20 into the mounting hole of the aluminum alloy air cylinder tube seat 10 and reaching the set torque value, ultrasonic assistance is simultaneously applied to the outer wall of the aluminum alloy air cylinder tube seat 10. The specific process parameters are: ultrasonic frequency 20-40 kHz, amplitude 3-8 μm, and application time 5-15 seconds. This ultrasonic-assisted process produces the following synergistic effects: 1) High-frequency micro-vibration significantly reduces the viscosity of the epoxy adhesive, promoting its flow and complete filling into the deep thread meshing gap, effectively eliminating trapped air and avoiding bubble defects; 2) The energy input of ultrasound can trigger a partial cross-linking reaction of epoxy resin molecules at room temperature or lower temperatures, achieving preliminary pre-curing, thereby obtaining a high initial bond strength before final static curing, which is beneficial for subsequent workpiece transfer and preliminary operations during the curing waiting period.

[0054] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0055] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A threaded sealing structure for an aluminum alloy gas storage tank, characterized in that, include: An aluminum alloy air cylinder pipe seat (10) is provided with a mounting hole with internal threads; A stainless steel sealing sleeve (20) is coaxially assembled in the mounting hole. The outer wall of the stainless steel sealing sleeve (20) is provided with an external thread that matches the internal thread. The internal thread of the aluminum alloy air cylinder pipe seat (10) is a non-sealing pipe thread. The first high-temperature epoxy adhesive layer is cured and formed in the meshing gap between the internal thread of the aluminum alloy air cylinder pipe seat (10) and the external thread of the stainless steel sealing sleeve (20), forming a structural bond.

2. The threaded sealing structure for the aluminum alloy gas storage tank as described in claim 1, characterized in that: The stainless steel sealing sleeve (20) includes an integrally formed interference fit portion (21) and a threaded connection portion (22), wherein: The outer diameter of the interference fit part (21) is larger than the outer diameter of the threaded connection part (22), forming a stepped tubular structure; A second high-temperature epoxy layer is filled between the axial end face of the interference fit part (21) and the end face of the aluminum alloy air cylinder pipe seat (10).

3. The threaded sealing structure for the aluminum alloy gas storage tank as described in claim 2, characterized in that: The aluminum alloy air cylinder pipe seat (10) has an annular sealing groove (30) on its end face, and the annular sealing groove (30) is filled with the second high-temperature epoxy adhesive layer; and / or, the threaded connection part (22) has an annular conical groove (40) at one end away from the interference fit part (21), and the annular conical groove (40) is filled with the first high-temperature epoxy adhesive layer.

4. The threaded sealing structure for the aluminum alloy gas storage tank as described in claim 2, characterized in that: The threaded connection portion (22) is provided with an annular stress relief groove (50) at one end near the interference fit portion (21); and / or, at least one of the first high-temperature epoxy adhesive layer and the second high-temperature epoxy adhesive layer is an epoxy resin adhesive with a temperature resistance range of -40℃ to 180℃.

5. The threaded sealing structure for an aluminum alloy gas storage tank as described in any one of claims 1-4, characterized in that: The inner thread surface of the aluminum alloy air cylinder pipe seat (10) is anodized to form an anodized layer.

6. The threaded sealing structure for an aluminum alloy gas storage tank as described in any one of claims 1-4, characterized in that: The external thread surface of the stainless steel sealing sleeve (20) is coated with a silane coupling agent.

7. The threaded sealing structure for an aluminum alloy gas storage tank as described in claim 5, characterized in that: The anodic oxide layer is a hard anodic oxide layer. After the surface of the hard anodic oxide layer is impregnated with polytetrafluoroethylene dispersion and dried, a friction-reducing and wear-resistant composite coating is formed.

8. The threaded sealing structure for an aluminum alloy gas storage tank as described in claim 2, characterized in that: At least one surface acoustic wave sensor is embedded in the end face of the interference fit portion (21) of the stainless steel sealing sleeve (20), and the antenna of the surface acoustic wave sensor extends into the second high-temperature epoxy layer; and / or, at least one of the first high-temperature epoxy layer and the second high-temperature epoxy layer is doped with thermochromic pigment particles.

9. The method for assembling the threaded sealing structure of the aluminum alloy gas storage tank as described in any one of claims 1-8, characterized in that, Includes the following steps: The internal threads of the aluminum alloy air cylinder pipe seat (10) are anodized. A silane coupling agent is coated on the external thread surface of the stainless steel sealing sleeve (20); Epoxy resin adhesive is uniformly applied to the inner thread surface of the aluminum alloy air cylinder pipe seat (10) and the outer thread surface of the stainless steel sealing sleeve (20). Screw the stainless steel sealing sleeve (20) into the mounting hole of the aluminum alloy air cylinder pipe seat (10) to the set torque value, and let it stand to cure.

10. The method for assembling the threaded sealing structure of the aluminum alloy gas storage tank as described in claim 9, characterized in that: The set torque value is 5-8 N·m, and the curing time is 24 hours.

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