Heating tube sealing process of baking tray

Abstract

The invention discloses a heating tube sealing process of a baking tray. The method comprises the following steps: peeling powder from a heating pipe orifice, accurately controlling the depth to be 4-5mm, and blowing away internal magnesium powder by using an air gun to ensure that a cold needle extends out of the pipe orifice. And then, a dispensing needle head extends into a pipe opening, high-temperature sealing silica gel is injected from deep to shallow, and standing and curing are conducted for not less than 10 hours after air is exhausted. And then the glue is supplemented and injected for the second time from the outside of the pipe orifice, the depth is 0.5 mm-1. 5mm, and the end face of the conductive rod is coated with the glue. And finally, a silica gel cap and a conductive rod are placed in sequence to realize sealed connection. According to the process, deep air is effectively removed through secondary glue injection, micropores are filled, the porosity is reduced, and the problem of incomplete sealing is solved; powder stripping creates conditions for silica gel permeation, and the sealing effect is enhanced; the silica gel cap elastic compression sealing and the conductive rod end face gluing plane sealing form double protection, dependence on component size precision is reduced, assembly stability is improved, and the sealing device is suitable for baking tray heating pipe sealing in the high-temperature and high-humidity environment.

Description

Technical Field

[0001] The present invention relates to the technical field of heating tube sealing, and in particular to a heating tube sealing process for a baking tray. Background Art

[0002] In the field of electric heating appliance manufacturing, bakeware is a common kitchen appliance. The sealing performance of its core heating components (such as the heating element) directly affects the product's safety, service life, and thermal efficiency. The heating element is typically composed of a metal tube, an internal magnesium powder insulation layer, and a conductive rod. The sealing process must address two key issues: first, preventing the magnesium powder from becoming oxidized due to moisture, which could degrade the insulation performance; second, avoiding the risk of seal failure or leakage caused by internal gas expansion during high-temperature operation. However, existing sealing processes suffer from the following technical flaws, making it difficult for bakeware products to achieve a balanced balance between sealing reliability and manufacturing efficiency.

[0003] Existing methods for sealing heating tubes involve injecting silicone directly into the tube opening and curing it. This makes it difficult to completely remove air from the tube, especially in areas where the magnesium powder is loose, which can easily form air holes and lead to incomplete sealing. Furthermore, the silicone cap size must match the height of the tube opening; even the slightest deviation can lead to seal failure and a low yield rate. Summary of the Invention

[0004] The purpose of the present invention is to disclose a sealing process for the heating tube of a baking tray. By optimizing the entire process of pretreatment, glue injection, curing and assembly, the present invention systematically solves the core problems of the prior art, such as incomplete sealing, poor assembly stability and insufficient durability. The present invention is particularly suitable for the long-life sealing requirements of the baking tray heating tube in high temperature and high humidity environments.

[0005] In order to achieve the above-mentioned purpose, the present invention discloses a heating tube sealing process for a baking tray, comprising the following steps: performing a powder stripping treatment on the heating tube mouth, with the powder stripping depth accurately controlled to be between 4mm and 5mm; using an air gun to blow away loose magnesium powder inside the tube mouth, ensuring that the interior of the heating tube mouth is clean and free of impurities, and the heating tube cold needle extends from the heating tube along its axis to the heating tube mouth; inserting a dispensing needle into the heating tube mouth after the powder stripping, and injecting high-temperature sealing silicone from the depth direction of the heating tube mouth from deep to shallow, so that the injected high-temperature sealing silicone spreads from the bottom of the tube to the tube mouth and air is expelled; standing the heating tube mouth with the heat facing up for curing, and the curing time is not less than 10 hours to ensure that the injected silicone fluid is completely dry; performing a second supplementary glue injection from the outside of the heating tube mouth with the dispensing needle, with the glue injection depth controlled to be between 0.5mm and 1.5mm, and evenly applying glue on the end face of the conductive rod; placing a silicone cap and a conductive rod in the heating tube mouth in sequence, so that the silicone cap is sealed and connected to the heating tube mouth, and the conductive rod is sealed and connected to the silicone cap.

[0006] By adopting this solution, secondary glue injection effectively removes deep-seated air; secondary filling further fills any micropores, forming a bubble-free sealing layer. This significantly reduces porosity and effectively resolves the issue of incomplete sealing. Precisely controlling the powder stripping depth to 4mm-5mm creates optimal conditions for deep silicone penetration, enabling it to better fill the interface between the magnesium powder layer and the tube, enhancing the sealing effect. The dual protective barrier created by combining the elastic compression seal of the silicone cap with the flat seal of the conductive rod end face further enhances sealing reliability. This structurally coordinated sealing approach reduces reliance on the dimensional accuracy of individual components and significantly improves assembly stability.

[0007] Furthermore, the portion of the heating tube cold needle extending out of the heating tube port is provided with an external thread, and the conductive rod is screwed into the external thread of the heating tube cold needle by an electric screwdriver and locked until the silicone cap expands.

[0008] By adopting the above solution, when the conductive rod is screwed into the external thread of the cold needle using an electric screwdriver, a continuous and uniform axial pressure is applied to the silicone cap. The silicone cap undergoes elastic deformation under the action of pressure, and its inner wall fits more tightly against the heating tube mouth and the surface of the conductive rod, filling any microscopic gaps that may exist, effectively preventing environmental moisture, dust and other impurities from entering the interior of the heating tube, and preventing magnesium powder from getting damp and oxidizing, thereby improving the insulation performance and sealing reliability of the heating tube. The external thread of the cold needle provides a precise positioning reference for the installation of the conductive rod. During the assembly process, the operator only needs to align the conductive rod with the external thread of the cold needle and screw it in using an electric screwdriver. There is no need for complicated alignment operations, which greatly improves the accuracy and consistency of the assembly. At the same time, the use of an electric screwdriver enables rapid tightening, reduces the time and labor intensity of manual operations, and improves assembly efficiency.

[0009] Furthermore, the silicone cap is squeezed by the conductive rod to expand the nail in a range of 13.8mm-14.5mm.

[0010] By adopting the above solution, the expansion range ensures that the silicone cap can fully fill the annular space between the heating tube nozzle and the conductive rod, maximizing the contact area with both. The silicone material has good flexibility and elasticity. After being squeezed and expanded, its surface can closely fit the inner wall of the heating tube nozzle and the outer wall of the conductive rod, forming a continuous, gapless sealing barrier. This effectively prevents moisture, dust, impurities, etc. in the environment from entering the interior of the heating tube, and prevents magnesium powder from getting wet and oxidizing, thereby ensuring the insulation performance and service life of the heating tube. After the silicone cap expands to 13.8mm - 14.5mm, it can be firmly stuck to the heating tube nozzle, forming a tight mechanical fit with the nozzle. It will not cause a loose seal due to insufficient expansion, nor will it cause excessive squeezing of the heating tube nozzle due to excessive expansion, thereby damaging the nozzle structure. This ensures a perfect fit between the silicone cap and the heating tube nozzle.

[0011] Furthermore, the conductive rod and the cold pin of the heating tube are sealed and fixed by a riveting clamp.

[0012] By adopting the above solution, the riveting fixture can accurately control the force and position of the riveting, so that the stress is evenly distributed at the connection point between the conductive rod and the cold needle. Compared with traditional welding or threaded connections, uniform stress distribution can reduce local stress concentration, reduce the risk of fracture or damage at the connection point due to excessive stress, and improve the strength and durability of the connection. After the conductive rod and the cold needle of the heating tube are sealed, they are riveted and fixed. The pressure generated during the riveting process can make the sealing structure tighter. It can limit the relative movement of the conductive rod and the cold needle, and avoid the damage of the sealing structure due to factors such as vibration, thermal expansion and contraction. Even in harsh operating environments, the long-term stability of the sealing performance can be guaranteed, reducing safety hazards such as leakage and short circuit caused by sealing failure.

[0013] Furthermore, after the heating pipe opening is sealed, the entire heating pipe is die-casted using an embedded pipe die-casting process, and the heating pipe and the baking tray are die-casted.

[0014] By adopting this solution, the buried tube die-casting process uses high pressure to wrap the aluminum alloy solution around the heating tube, creating a seamless connection between the two. This integrated structure eliminates the risk of seal failure caused by aging, loosening, or high-temperature deformation associated with traditional sealing methods (such as sealing rings). It effectively prevents moisture, dust, and other impurities from entering the heating tube, protecting the magnesium powder insulation layer from damage, thereby improving the product's insulation performance and safety. It also avoids structural weaknesses caused by loose components or weak connections in traditional assembly methods. This integrated design can withstand greater mechanical shock and vibration, ensuring product stability during transportation and use.

[0015] Furthermore, in the step of standing and drying with the heating pipe opening facing upward, the temperature of the drying environment is controlled at 20-30° C., and the humidity is controlled at 40%-60%.

[0016] By adopting this solution, moisture and humidity can reduce the resistance of the insulation material and increase the risk of leakage. In a dry environment with temperatures between 20-30°C and a humidity of 40%-60%, moisture can be effectively removed from the interior and surface of the heating element, keeping the insulation material dry and maintaining its excellent insulation performance.

[0017] Furthermore, the silicone cap is made of high-temperature silicone material with a temperature resistance of ≥300°C, and has an initial height of 10mm.

[0018] By adopting this solution, the heating element will generate a high temperature during prolonged use of the baking tray, generally far exceeding normal temperature. High-temperature silicone material with a temperature resistance of ≥300°C can withstand this high-temperature environment and will not soften, deform, or melt due to the temperature increase, thus maintaining a good sealing performance. For example, during continuous high-temperature baking, ordinary silicone may lose its elasticity due to its inability to withstand the high temperature, resulting in seal failure, allowing moisture, dust, etc. to enter the interior of the heating element and affect its normal operation. However, the high-temperature silicone cap can stably perform its sealing function and prevent the intrusion of external impurities.

[0019] Furthermore, the high-temperature sealing silicone adopts high-temperature red sealing silicone, and the temperature resistance grade of the high-temperature red sealing silicone is ≥250°C.

[0020] By adopting this solution, high-temperature red sealing silicone with a temperature resistance rating of 250°C or higher can withstand such high temperatures without softening, deforming, or melting due to the temperature increase. This ensures that the silicone cap can tightly wrap around the conductive rod even at high temperatures, effectively preventing gas and liquid leakage and preventing moisture, dust, and other substances from entering the heating element, thereby protecting its normal operation. It is also less susceptible to aging symptoms such as cracking, hardening, and loss of elasticity, thereby extending the service life of the silicone cap. This reduces the frequency of replacement due to aging and damage, reducing operating costs.

[0021] Furthermore, the riveting pressure of the riveting fixture is 5-8 MPa to ensure an airtight connection between the conductive rod and the cold pin of the heating tube.

[0022] By adopting this solution, a riveting pressure of 5-8 MPa ensures that the conductive rod and the heating element cold pin form a single, integrated structure. This structure possesses high strength and rigidity, effectively resisting vibration and impact, and preventing the connection from loosening or breaking. Controlling the riveting pressure within a relatively clear range of 5-8 MPa provides clear guidance for production operations, helping to improve production efficiency and reduce quality issues caused by improper operation.

[0023] Furthermore, in the steps of installing the silicone cap and connecting the conductive rod, the cold needle thread is cleaned and lubricated before the conductive rod is driven into the cold needle thread.

[0024] By adopting this solution, these impurities can be effectively removed, leaving the thread surface clean and smooth. This allows the conductive rod to be driven more smoothly into the cold needle thread, achieving a tight mechanical connection and enhancing the stability of the connection, preventing problems such as loosening and falling off during use. The cleaned cold needle thread and the conductive rod have a smaller gap, which can better cooperate with the silicone cap to form an effective sealing structure. Lubrication can further fill the tiny gaps between the threads, reduce leakage paths, and improve the airtightness and liquid tightness of the entire connection, ensuring the proper operation of the heating element.

[0025] Compared with the prior art, the present invention has the following beneficial effects: 1. High-temperature sealing silicone is injected from the depth of the heating tube opening to the shallowest part, allowing the silicone to spread from the bottom of the tube to the opening, initially removing air. A second injection is then performed to further fill any micropores, forming a bubble-free sealing layer. This significantly reduces porosity and effectively resolves the issue of incomplete sealing. It can better prevent the magnesium powder from becoming damp and oxidizing, which could lead to a decrease in insulation performance, and avoid the risk of internal gas expansion causing seal failure or leakage during high-temperature operation. 2. The powder stripping depth is precisely controlled at 4mm-5mm, creating good conditions for deep penetration of silicone. The silicone can better fill the contact interface between the magnesium powder layer and the tube body, making the sealing layer more tightly integrated with the internal structure of the heating tube, enhancing the sealing effect and improving the reliability of the seal. 3. By sequentially placing a silicone cap and a conductive rod at the mouth of the heating tube, a dual protective structure is formed: a sealed connection between the silicone cap and the heating tube mouth, and a sealed connection between the conductive rod and the silicone cap. The combination of the elastic compression seal of the silicone cap and the flat seal of the conductive rod's end face further enhances the reliability of the seal, providing more reliable sealing protection for the heating tube. The dual sealing structure and optimized glue injection process reduce the reliance on the dimensional accuracy of individual components. Even if there are certain deviations in the size of the silicone cap, the dual sealing and the filling effect of the silicone can ensure the sealing effect, greatly improving assembly stability and reducing the problem of sealing failure caused by size mismatch. 4. High-temperature sealing silicone has excellent high-temperature resistance and can maintain stable sealing performance in high-temperature environments, and is not easily softened, deformed, or failed. At the same time, the effective sealing structure prevents moisture from entering the interior of the heating tube, protecting the magnesium powder from moisture and oxidation, extending the service life of the heating tube, improving product quality, and making the internal structure of the heating tube more stable. The filling and sealing effect of the silicone can fix the position of the magnesium powder, reduce the movement and sedimentation of the magnesium powder during high-temperature operation, and maintain the electrical performance of the heating tube stable. In addition, the double sealing structure also enhances the overall mechanical strength of the heating tube, improves its vibration and impact resistance, and further ensures the durability of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 A schematic diagram of the three-dimensional structure of an embodiment of the present invention; Figure 2 This is a schematic diagram of a partial explosion structure of an embodiment of the present invention; Figure 3 Schematic diagram of the cross-sectional structure of an embodiment of the present invention.

[0028] Explanation of the main reference numerals: 1. Heating tube; 11. Heating tube mouth; 12. Heating tube cold needle; 13. High-temperature sealing silicone; 2. Dispensing needle; 3. Silicone cap; 4. Conductive rod. DETAILED DESCRIPTION

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0030] In the present invention, terms such as "upper," "lower," "left," "right," "front," "back," "top," "bottom," "inner," "outer," "center," "vertical," "horizontal," "transverse," and "longitudinal" indicate positions or locations based on the positions or locations shown in the accompanying drawings. These terms are primarily intended to better describe the present invention and its embodiments and are not intended to limit the devices, elements, or components indicated to having a specific orientation, or to being constructed or operated in a specific orientation.

[0031] Furthermore, some of the above terms may be used to express other meanings besides indicating a position or location. For example, the term "on" may also be used to indicate a dependency or connection in certain circumstances. Those skilled in the art will understand the specific meanings of these terms in the present invention based on the specific circumstances.

[0032] Furthermore, the terms "installed," "disposed," "provided with," "connected," and "connected" should be interpreted broadly. For example, they can refer to fixed connections, removable connections, or integral structures; mechanical connections or electrical connections; direct connections or indirect connections through an intermediary; or internal communication between two devices, elements, or components. Those skilled in the art will understand the specific meanings of these terms in the present invention based on specific circumstances.

[0033] Furthermore, the terms "first," "second," and the like are primarily used to distinguish different devices, elements, or components (which may or may not be the same in type and configuration) and are not intended to indicate or imply the relative importance or quantity of the devices, elements, or components indicated. Unless otherwise specified, "plurality" means two or more.

[0034] The technical solution of the present invention will be further described below in conjunction with embodiments and drawings.

[0035] Example 1 of the present invention please refer to Figures 1 to 3 As shown, a sealing process for the heating tube 1 of a baking tray is provided, comprising the following steps: S1. Pretreatment stage: The heating nozzle 11 is manually or mechanically powdered, and the depth is controlled between 4mm-5mm. The heating nozzle 11 is purged with 0.6MPa compressed air through an air gun to remove magnesium oxide debris and ensure that the interior of the heating nozzle 11 is clean and free of impurities.

[0036] S2: Glue injection and sealing stage: Use a conical dispensing needle 2 to insert into the root of the pipe mouth, that is, deep in the powder stripping mouth. The diameter of the conical dispensing needle 2 can be selected as 1.2mm. High-temperature sealing silicone 13 is injected into the root of the pipe mouth through the conical dispensing needle 2. Optionally, the high-temperature sealing silicone 13 uses high-temperature red sealing silicone with a temperature resistance of 300°C. The injection speed is 0.05ml / s and the injection volume is 0.8ml. When injecting glue, the dispensing needle 2 is inserted into the heating pipe mouth 11 after powder stripping, and the high-temperature sealing silicone 13 is injected from deep to shallow in the depth direction of the heating pipe mouth 11. During the injection process, the dispensing head gradually rises until the high-temperature sealing silicone 13 spreads from the bottom of the pipe to the pipe mouth and the air is expelled.

[0037] S3: Curing in a static state: Place the heating nozzle 11 facing upward and allow the device to cure for at least 10 hours to ensure that the injected silicone fluid is completely dry. Optionally, allow the device to stand at a temperature of 20-30°C and a humidity of 40%-60%; preferably, at a temperature of 25°C ± 2°C and a humidity of 50% ± 5% for 12 hours. During the curing phase, precisely control the ambient temperature and humidity to ensure complete polymerization of the silicone.

[0038] S4: Secondary glue filling and assembly: The glue dispensing needle 2 is injected with glue for the second time from the outside of the heating tube mouth 11. The injection depth is controlled between 0.5mm-1.5mm, preferably 1.0mm, and the injection volume is 0.2ml. The heating tube cold needle 12 extends from the heating tube 1 along its axis to the heating tube mouth 11; glue is evenly applied to the end face of the conductive rod 4. Specifically, the glue application method is roller coating, and the thickness of the roller-coated silicone film is 0.3mm. The silicone cap 3 is sleeved and wrapped around the heating tube mouth 11. The secondary glue injection can effectively exclude deep air; the secondary filling further fills the possible micropores to form a bubble-free sealing layer, which greatly reduces the porosity and effectively solves the problem of incomplete sealing. The powder stripping depth is precisely controlled at 4mm-5mm to create good conditions for the deep penetration of silicone, so that the silicone can better fill the contact interface between the magnesium powder layer and the tube body, thereby enhancing the sealing effect. The double protective barrier formed by the elastic compression seal of the silicone cap 3 and the flat seal of the end face of the conductive rod 4 further enhances the reliability of the seal. This structurally coordinated sealing approach reduces reliance on the dimensional accuracy of individual components and significantly improves assembly stability. The portion of the heating tube cold needle 12 extending from the heating nozzle 11 is provided with external threads. Using an electric screwdriver, the conductive rod 4 is screwed onto the external threads of the heating tube cold needle 12 and tightened until the silicone cap 3 expands to 13.8mm-14.5mm, preferably 14.2±0.2mm, ensuring a sealed connection between the silicone cap 3 and the heating nozzle 11, and between the conductive rod 4 and the silicone cap 3. As the conductive rod 4 is screwed into the external threads of the cold needle using an electric screwdriver, it exerts continuous and uniform axial pressure on the silicone cap 3. Under the pressure, the silicone cap 3 elastically deforms, tightening its inner wall to the heating nozzle 11 and the conductive rod 4 surfaces. This fills any microscopic gaps, effectively preventing ambient moisture, dust, and other impurities from entering the interior of the heating tube 1 and preventing oxidation of magnesium powder due to moisture, thereby improving the insulation performance and sealing reliability of the heating tube 1. The external threads of the cold needle provide a precise positioning reference for the installation of the conductive rod 4. During assembly, the operator only needs to align the conductive rod 4 with the cold pin's external thread and screw it in using an electric screwdriver, eliminating the need for complex alignment operations. This significantly improves assembly accuracy and consistency. Furthermore, the use of an electric screwdriver allows for rapid tightening, reducing manual operation time and labor intensity, and improving assembly efficiency.

[0039] S5: Mechanical reinforcement: The conductive rod 4 and the heating tube cold needle 12 are sealed and fixed by a riveting fixture. The riveting pressure of the riveting fixture is 5-8MPa to ensure an airtight connection between the conductive rod 4 and the heating tube cold needle 12. The riveting pressure of 5-8MPa makes the conductive rod 4 and the heating tube cold needle 12 form an integral structure. This integral structure has high strength and rigidity, can effectively resist the influence of vibration and impact force, and prevent the connection part from loosening or breaking. Controlling the riveting pressure within the relatively clear range of 5-8MPa provides clear guidance for production operations. This helps to improve production efficiency and reduce quality problems caused by improper operation. Specifically, the riveting fixture applies a pressure of 6.5MPa to fix the conductive rod 4 and the heating tube cold needle 12, and detects the sealing surface gap ≤0.05mm. The riveting fixture can accurately control the force and position of the riveting so that the stress is evenly distributed at the connection between the conductive rod 4 and the cold needle. Compared with traditional welding or threaded connections, uniform stress distribution can reduce local stress concentration, reduce the risk of fracture or damage at the connection due to excessive stress, and improve the strength and durability of the connection. After the conductive rod 4 and the heating tube cold needle 12 are sealed, they are riveted and fixed. The pressure generated during the riveting process can make the sealing structure tighter. It can limit the relative movement of the conductive rod 4 and the cold needle to avoid the destruction of the sealing structure due to vibration, thermal expansion and contraction and other factors. Even in harsh operating environments, the long-term stability of the sealing performance can be guaranteed, reducing safety hazards such as leakage and short circuit caused by sealing failure. The 5-8MPa riveting pressure causes microscopic bite at the metal-silicone interface, improving the airtightness of the connection.

[0040] S6: buried tube die-casting: After the heating tube mouth 11 is sealed, the entire heating tube 1 is subjected to buried tube die-casting process, and the heating tube 1 and the baking tray are die-cast. Optionally, the sealed heating tube 1 is placed in a baking tray mold, and the aluminum alloy melt is die-cast at 680°C with a holding pressure of 80MPa. The buried tube die-casting process wraps the heating tube 1 with the aluminum alloy solution under high pressure, so that the two are seamlessly connected. This integrated structure avoids the risk of sealing failure caused by traditional sealing methods such as sealing rings due to aging, loosening or high-temperature deformation, effectively prevents impurities such as moisture and dust from invading the interior of the heating tube 1, and protects the magnesium powder insulation layer from damage, thereby improving the insulation performance and safety of the product. It avoids the structural weaknesses caused by loose components or loose connections in traditional assembly methods. This integrated design can withstand greater mechanical shock and vibration, ensuring the stability of the product during transportation and use.

[0041] In this embodiment 1, the silicone cap 3 is made of high-temperature silicone material with a temperature resistance of ≥300°C and an initial height of 10mm. This configuration allows the heating tube 1 to generate a relatively high temperature during prolonged use of the baking tray, generally far exceeding normal temperature. High-temperature silicone material with a temperature resistance of ≥300°C can withstand such a high-temperature environment and will not soften, deform, or melt due to temperature increases, thereby always maintaining good sealing performance. For example, during continuous high-temperature baking, ordinary silicone may lose its elasticity due to its inability to withstand high temperatures, resulting in seal failure, allowing moisture, dust, etc. to enter the interior of the heating tube 1 and affect its normal operation; however, the high-temperature silicone cap 3 can stably perform its sealing function to prevent the intrusion of external impurities.

[0042] In this embodiment 1, the high-temperature sealing silicone 13 is made of high-temperature red sealing silicone. The temperature resistance level of the high-temperature red sealing silicone is ≥250°C. The high-temperature red sealing silicone with a temperature resistance level of ≥250°C can withstand such a high-temperature environment and will not soften, deform or melt due to the increase in temperature. This ensures that the silicone cap 3 can still tightly wrap the conductive rod 4 at high temperatures, effectively blocking gas and liquid leakage, preventing moisture, dust, etc. from entering the interior of the heating tube 1, and protecting its normal operation. It is less likely to experience aging phenomena such as cracking, hardening, and loss of elasticity, thereby extending the service life of the silicone cap 3. This reduces the frequency of replacement due to aging and damage of the silicone cap 3, and reduces the cost of use.

[0043] In some embodiments, during the steps of installing the silicone cap 3 and connecting it to the conductive rod 4, the cold needle thread is cleaned and lubricated before the conductive rod 4 is driven into the cold needle thread. This can effectively remove these impurities, making the thread surface clean and smooth, allowing the conductive rod 4 to be driven into the cold needle thread more smoothly, achieving a tight mechanical connection, enhancing the stability of the connection, and preventing problems such as loosening and falling off during use. The gap between the cold needle thread and the conductive rod 4 after cleaning is smaller, and can better cooperate with the silicone cap 3 to form an effective sealing structure. The lubrication treatment can further fill the tiny gaps between the threads, reduce leakage channels, improve the air tightness and liquid tightness of the entire connection part, and ensure the normal operation of the heating tube 1.

[0044] Validation Experimental Design: Purpose of the experiment: Compare the performance differences between traditional processes and this process in the three dimensions of sealing, durability, and production efficiency.

[0045] Experiment 1: Effect of powder stripping depth on sealing effect: Table 1

[0046] As shown in Table 1, the best magnesium powder-silicone interface bonding is achieved at a depth of 4mm-5mm.

[0047] For the first time, high-temperature red sealing silicone with a temperature resistance of over 250°C is injected from the root of the pipe bottom, penetrating the magnesium powder layer with a peeling depth of 4-5mm to form the main sealing area; for the second time, a layer of 0.5mm-1.5mm filling glue is formed outside the pipe mouth to construct a dense surface layer. The double injection reduces the porosity to below 0.4%.

[0048] Experiment 2: Relationship between silicone cap expansion rate and sealing strength: Table 2

[0049] Table 2 shows that 13.8mm-14.5mm is the optimal elastic deformation range. By utilizing the silicone cap's controllable expansion deformation of 38%-45%, manufacturing tolerances are effectively compensated. The radial extrusion force generated when the conductive rod is screwed in drives the silicone to fill the microscopic gaps at the metal interface, forming an adaptive sealing barrier.

[0050] See Figure 3 As shown, the sealing process of the heating tube 1 of the present invention exists at both ends of the heating tube 1 to form two conductive rods 4 of the heating tube 1.

[0051] Compared with the prior art, the present invention has the following beneficial effects: 1. High-temperature sealing silicone rubber 13 is injected from the depth of the heating tube opening 11 downward, allowing the silicone to spread from the bottom of the tube to the opening, initially removing air. A second injection is then performed to further fill any remaining micropores, forming a bubble-free sealing layer. This significantly reduces porosity and effectively resolves the issue of incomplete sealing. It also prevents moisture and oxidation of the magnesium powder, which can lead to reduced insulation performance, and avoids the risk of seal failure or electrical leakage caused by internal gas expansion during high-temperature operation. 2. The powder stripping depth is precisely controlled at 4mm-5mm, creating excellent conditions for deep silicone penetration. The silicone can better fill the contact interface between the magnesium powder layer and the tube body, making the sealing layer more tightly bonded to the internal structure of the heating tube 1, enhancing the sealing effect and improving the sealing reliability. 3. By sequentially placing the silicone cap 3 and the conductive rod 4 into the heating tube opening 11, a dual protective structure is formed: the silicone cap 3 is sealed to the heating tube opening 11, and the conductive rod 4 is sealed to the silicone cap 3. The combination of the elastic compression seal of the silicone cap 3 and the flat seal of the conductive rod 4's end surface further enhances sealing reliability, providing more reliable sealing protection for the heating tube 1. This dual sealing structure and optimized glue injection process reduce reliance on the dimensional accuracy of individual components. Even if there are certain dimensional deviations in the silicone cap 3, the dual sealing and silicone filling effect ensure a good seal, significantly improving assembly stability and reducing seal failures caused by dimensional mismatches. 4. The high-temperature sealing silicone rubber 13 has excellent high-temperature resistance and can maintain stable sealing performance in high-temperature environments, and is not easily softened, deformed, or failed. At the same time, the effective sealing structure can prevent moisture from entering the interior of the heating tube 1, avoiding oxidation of the magnesium powder due to moisture, thereby extending the service life of the heating tube 1, improving product quality, and making the internal structure of the heating tube 1 more stable. The filling and sealing effect of the silicone rubber can fix the position of the magnesium powder, reduce the movement and sedimentation of the magnesium powder during high-temperature operation, and maintain the stable electrical performance of the heating tube 1. In addition, the double sealing structure can also enhance the overall mechanical strength of the heating tube 1, improve its vibration and impact resistance, and further ensure the durability of the product.

[0052] The technical means disclosed in the solutions of the present invention are not limited to those disclosed in the above-mentioned embodiments, but also include technical solutions composed of any combination of the above-mentioned technical features. It should be noted that those skilled in the art may make various improvements and modifications without departing from the principles of the present invention, and such improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A process for sealing a heating tube (1) of a baking tray, characterized in that: The steps include: The heating pipe mouth (11) is subjected to a powder stripping process, and the powder stripping depth is precisely controlled between 4 mm and 5 mm; the loose magnesium powder inside the pipe mouth is blown away with an air gun to ensure that the inside of the heating pipe mouth (11) is clean and free of impurities, and the heating pipe cold needle (12) extends from the heating pipe (1) along its axis to the heating pipe mouth (11); Insert the dispensing needle (2) into the heating pipe mouth (11) after the powder is stripped, and inject high-temperature sealing silica gel (13) from the depth direction of the heating pipe mouth (11) from deep to shallow, so that the high-temperature sealing silica gel (13) spreads from the bottom of the pipe to the pipe mouth and exhausts air; The heating pipe opening (11) is placed upward to cure, and the curing time is not less than 10 hours to ensure that the injected silicone fluid is completely dry; The dispensing needle (2) is used to perform a second supplementary injection of glue from the outside of the heating pipe opening (11), the injection depth is controlled between 0.5 mm and 1.5 mm, and the glue is evenly applied to the end surface of the conductive rod (4); A silicone cap (3) and a conductive rod (4) are sequentially placed in the heating pipe opening (11) so that the silicone cap (3) is sealedly connected to the heating pipe opening (11), and the conductive rod (4) is sealedly connected to the silicone cap (3).

2. The sealing process for the heating tube (1) of a baking tray according to claim 1, characterized in that: The portion of the heating tube cold needle (12) extending out of the heating tube port (11) is provided with an external thread, and the conductive rod (4) is screwed into the external thread of the heating tube cold needle (12) by an electric screwdriver and locked until the silicone cap (3) expands.

3. The sealing process for the heating tube (1) of a baking tray according to claim 2, characterized in that: The silicone cap (3) is squeezed by the conductive rod (4) to expand the nail in a range of 13.8mm-14.5mm.

4. The sealing process for the heating tube (1) of a baking tray according to claim 1, characterized in that: The conductive rod (4) and the heating tube cold needle (12) are sealed and fixed by a riveting clamp.

5. The sealing process for the heating tube (1) of a baking tray according to claim 1, characterized in that: After the heating pipe opening (11) is sealed, the entire heating pipe (1) is die-casted using an embedded pipe die-casting process to form the heating pipe (1) and the baking tray.

6. The sealing process for the heating tube (1) of a baking tray according to claim 1, characterized in that: In the step of standing and drying with the heating pipe opening (11) facing upward, the temperature of the drying environment is controlled at 20-30° C., and the humidity is controlled at 40%-60%.

7. The sealing process for the heating tube (1) of a baking tray according to claim 1, characterized in that: The silicone cap (3) is made of high-temperature silicone material with a temperature resistance of ≥300°C and an initial height of 10 mm.

8. The sealing process for the heating tube (1) of a baking tray according to claim 1, characterized in that: The high-temperature sealing silica gel (13) is a high-temperature red sealing silica gel, and the temperature resistance grade of the high-temperature red sealing silica gel is ≥250°C.

9. The sealing process for the heating tube (1) of a baking tray according to claim 4, characterized in that: The riveting pressure of the riveting fixture is 5-8 MPa to ensure an airtight connection between the conductive rod (4) and the heating tube cold needle (12).

10. The sealing process for the heating tube (1) of a baking tray according to claim 1, characterized in that: In the step of installing the silicone cap (3) and connecting it to the conductive rod (4), the cold needle thread is cleaned and lubricated before the conductive rod (4) is driven into the cold needle thread.

Images