A method for potting and sealing electric heating tubes

Abstract

This invention relates to the field of electric heating tube processing technology, specifically to a method for potting and sealing electric heating tubes, comprising: preparing an electric heating tube and a sample tube; inserting a calibration lead-out rod into the sample tube; calibrating a co-permeation layer; and fabricating a custom lead-out rod; inserting the custom lead-out rod into the electric heating tube; mass-producing potting; and allowing the adhesive to solidify. Addressing the technical problems of existing sealing processes, this invention proposes a potting and sealing method for electric heating tubes that utilizes a first permeation hole on the custom lead-out rod. This allows air squeezed out during the permeation of the adhesive into the insulating powder to escape through the first permeation hole, preventing air bubbles from forming in the potting adhesive layer and thus affecting the insulation and sealing effect of the potting adhesive layer.

Description

Technical Field

[0001] This invention relates to the field of electric heating tube processing technology, specifically to a method for potting and sealing an electric heating tube. Background Technology

[0002] When manufacturing electric heating elements, the openings of the heating elements need to be sealed. The purpose of sealing is mainly to prevent moisture in the air from entering the interior of the heating element, causing the insulation material to become damp, which in turn reduces the insulation performance of the heating element and leads to product quality and safety issues.

[0003] In current industrial electric heating tube manufacturing processes, organic potting adhesives are commonly used to seal the tube openings. The method involves mixing liquid organic adhesive with a corresponding curing agent and pouring the mixture into the heating tube opening. After a period of time, the adhesive slowly cures on the surface of the insulating powder layer, eventually forming a hard, highly insulating solid that seals the opening. However, considering the physical properties of the insulating material itself, it is essentially a granular substance, and the insulating powder layer still contains air pores. Therefore, after the liquid adhesive is poured in, it seeps into the insulating powder layer, causing the air in the pores to rise and form bubbles. This results in pores during adhesive curing, with pores of varying sizes indicating a lack of insulation. Furthermore, these pores allow moisture from the air to enter the heating tube, rendering the seal ineffective. Summary of the Invention

[0004] To address the technical problems of defects in existing sealing processes, this invention provides a glue-filling and sealing method for electric heating tubes. It utilizes a first glue-permeation hole opened on a customized lead-out rod, allowing air squeezed out during the glue's penetration into the insulating powder to escape through the first glue-permeation hole. This prevents air bubbles from forming in the sealing glue layer, which would otherwise affect the insulation and sealing effect of the sealing glue layer.

[0005] The technical solution provided by this invention is: a method for potting and sealing an electric heating tube, comprising: preparing an electric heating tube and a sample tube: preparing an electric heating tube and a sample tube with the same structure as the electric heating tube, filling the electric heating tube and the sample tube with insulating powder to form an insulating powder layer; inserting a calibration lead-out rod into the sample tube: preparing a calibration lead-out rod, inserting the calibration lead-out rod into the insulating powder layer of the sample tube, and wrapping an insulating sheath around one end of the calibration lead-out rod using a heat-shrinking process, after heat shrinking, forming a gap D1 between the bottom end of the insulating sheath and the upper surface of the insulating powder layer; calibrating a co-permeation layer: pouring an insulating powder into the sample tube... The glue through gap D1 forms a calibration glue layer. Part of the glue in the calibration glue layer seeps down and mixes with the insulating powder to form a co-permeation layer. After the glue in the sample tube is completely cured, the sample tube is cut open, and the distance L between the bottom interface Q of the co-permeation layer and its upper surface is measured and recorded. A custom lead-out rod is fabricated: the top of the custom lead-out rod has a first hollow section, and the first hollow section has a first glue-permeation hole. The lowest first glue-permeation hole is located above the bottom surface of the first hollow section, and the distance E between the highest and lowest first glue-permeation holes satisfies E > L. The area between the bottom surface of the hollow section and the lowest first glue-permeable hole constitutes the first glue-retaining pit; a custom-made lead-out rod is inserted into the heating tube: the bottom interface Q is marked in the insulating powder layer according to the distance L in the heating tube, and the custom-made lead-out rod is inserted into the insulating powder layer of the heating tube, ensuring that the highest first glue-permeable hole is lower than the upper surface of the insulating powder layer, and the lowest first glue-permeable hole is lower than the marked bottom interface Q; and an insulating sheath is wrapped around one end of the custom-made lead-out rod using a heat-shrink process, with the bottom end of the heat-shrinked insulating sheath higher than the highest first glue-permeable hole, and the heat-shrinked insulating sheath... A gap D2 is formed between the bottom end of the sleeve and the upper surface of the insulating powder layer. Gap D2 is equal to gap D1. Batch production glue filling: Glue that covers gap D2 is poured into the heating tube to form a sealing glue layer. The thickness of the sealing glue layer is consistent with the standard glue layer. Some of the glue in the sealing glue layer seeps into the insulating powder layer. The glue displaces the air between the insulating powders. The air escapes to the atmosphere through the first glue penetration hole, or forms bubbles and flows into the first glue storage pit with the glue passing through the first glue penetration hole. Glue solidification and molding: Wait for the glue in the heating tube to fully solidify and complete the sealing.

[0006] Optionally, after the glue has solidified, a glue replenishment process is performed: glue is poured into the first hollow section until it covers the first glue penetration hole at the highest position.

[0007] Optionally, after fabricating the custom lead-out rod, the method also includes measuring and adjusting the depth of the first adhesive storage pit: insert the custom lead-out rod into a sample tube containing an insulating powder layer, pour adhesive into the sample tube with a thickness consistent with the calibrated adhesive layer, wait for the adhesive to seep in and cure, and after the adhesive in the sample tube has completely cured, cut the sample tube and the custom lead-out rod, measure and record the liquid level height of the adhesive in the first adhesive storage pit, and adjust the depth of the first adhesive storage pit of the remaining custom lead-out rods according to the liquid level height to ensure that the liquid level in the first adhesive storage pit is lower than the lowest first adhesive penetration hole; wherein, the depth of the first adhesive storage pit refers to the distance between the bottom surface of the first hollow section of the custom lead-out rod and the lowest first adhesive penetration hole.

[0008] Optionally, when making a custom lead-out rod, the distance between the first glue-dip hole at the lowest position and the bottom surface of the first hollow section is greater than or equal to 2 mm.

[0009] Optionally, after inserting the custom lead-out rod into the heating element, the method further includes: fabricating and inserting a gas guide rod; fabricating the gas guide rod includes: opening a second hollow section at the top of the gas guide rod, opening a second glue penetration hole on the second hollow section, the lowest second glue penetration hole being located above the bottom surface of the second hollow section, and the distance between the highest and lowest second glue penetration holes being greater than L, the area between the bottom surface of the second hollow section and the lowest second glue penetration hole forming a second glue storage pit; inserting the gas guide rod includes: inserting the gas guide rod into the insulating powder layer of the heating element, ensuring that the highest second glue penetration hole is lower than the upper surface of the insulating powder layer, while the lowest second glue penetration hole is lower than the marked bottom interface Q.

[0010] Optionally, when inserting a custom lead-out rod into the heating element, ensure that a portion of the first adhesive penetration hole is below the marked bottom interface Q.

[0011] Optionally, the distance E between the highest and lowest first glue-dip holes on the first hollow section satisfies E≥L+2 mm.

[0012] Optionally, the thickness of the calibration adhesive layer and the sealing adhesive layer is 8-10 mm.

[0013] Compared with the prior art, the technical solution provided by this invention has the following beneficial effects: In view of the technical problems of defects in the existing sealing process, the present invention proposes a glue-filling and sealing method for electric heating tubes. By using the first glue penetration hole opened on the customized lead rod, the air squeezed out during the glue penetration into the insulating powder can be discharged from the first glue penetration hole, avoiding the formation of air bubbles in the sealing glue layer, which would affect the insulation and sealing effect of the sealing glue layer. Attached Figure Description

[0014] Figure 1 This is a schematic diagram illustrating the implementation of the calibration co-permeation layer proposed in an embodiment of the present invention.

[0015] Figure 2 This is a schematic diagram of the structure of the customized lead-out rod proposed in an embodiment of the present invention.

[0016] Figure 3 This is a schematic diagram illustrating the implementation of the glue-filling and sealing method for the electric heating tube proposed in this embodiment of the invention.

[0017] Figure 4 This is a partially enlarged schematic diagram of the batch production glue-filling process proposed in an embodiment of the present invention.

[0018] Figure 5 This is a schematic diagram illustrating the implementation of the present invention after inserting a customized lead-out rod into the heating tube. Detailed Implementation

[0019] To further understand the content of this invention, a detailed description of the invention will be provided in conjunction with the accompanying drawings and embodiments.

[0020] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings. The terms "first," "second," etc., used in this invention are for the convenience of describing the technical solutions of the invention and have no specific limiting effect; they are all general terms and do not constitute a limitation on the technical solutions of the invention. It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of this application can be combined with each other. In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, not 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 the invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Multiple technical solutions in the same embodiment, as well as multiple technical solutions in different embodiments, can be arranged and combined to form new technical solutions that do not contradict or conflict, all of which are within the scope of protection claimed by this invention.

[0021] Example 1

[0022] Combined with appendix Figure 1 To be continued Figure 4 This embodiment proposes a method for potting and sealing an electric heating tube, which includes the first preparatory work, namely, preparing an electric heating tube 10 and a sample tube 11. Specifically, the electric heating tube 10 is prepared, and a sample tube 11 with the same structure as the electric heating tube 10 is prepared. Insulating powder is filled into the electric heating tube 10 and the sample tube 11 to form an insulating powder layer 12.

[0023] The insulating powder filling in sample tube 11 is for subsequent calibration of the co-permeation layer 16, while the insulating powder filling in heating tube 10 is for mass production. In practice, for the same model of heating tube 10, after the first use of sample tube 11, the sample tube 11 does not need to be used again in subsequent glue filling and sealing processes.

[0024] As attached Figure 1 As shown, after the sample tube 11 is prepared, a calibration lead-out rod 13 is inserted into the sample tube 11: The calibration lead-out rod 13 is inserted into the insulating powder layer 12 of the sample tube 11, and an insulating sheath 14 is wrapped around one end of the calibration lead-out rod 13 using a heat-shrink process. After heat shrinking, a gap D1 is formed between the bottom end of the insulating sheath 14 and the upper surface of the insulating powder layer 12. Generally, the distance between the bottom end of the insulating sheath 14 and the opening of the sample tube 11 is set to approximately 20 mm, and the resulting gap D1 is generally approximately 2 mm.

[0025] Subsequently, the co-permeation layer 16 was calibrated: adhesive was poured into the sample tube 11 to cover the gap D1 to form a calibration adhesive layer 15. Part of the adhesive in the calibration adhesive layer 15 seeped down and mixed with the insulating powder to form the co-permeation layer 16. After the adhesive in the sample tube 11 was completely cured, the sample tube 11 was cut open, and the distance L between the bottom interface Q of the co-permeation layer 16 and its upper surface was measured and recorded.

[0026] To simulate actual production, the temperature of the injected adhesive is set to 30–40°C. After the adhesive is injected into sample tube 11, the thickness of the calibrated adhesive layer 15 should be controlled between 8 and 10 mm, generally around 8 mm. Because the adhesive has strong viscosity and relatively low fluidity, the process of the adhesive penetrating into the insulating powder layer 12 is relatively slow after injection into sample tube 11. The thickness of the calibrated adhesive layer 15 here generally refers to the thickness immediately after the adhesive is injected into sample tube 11; at this point, the reduction in thickness due to penetration can be ignored.

[0027] As the adhesive slowly seeps and cures, it mixes with the insulating powder to form a co-permeable layer 16. The fully cured co-permeable layer 16 is a hard adhesive-insulating powder mixture. The co-permeable layer 16 will not loosen due to the cutting of the sample tube 11; therefore, the cut co-permeable layer 16 can be calibrated, and its bottom interface Q1 can be calibrated. The thickness of the co-permeable layer 16 is also marked, i.e., the distance L between the bottom interface Q and the upper surface of the co-permeable layer 16. Since the change in the height of the upper surface after the insulating powder is mixed with the adhesive is negligible, the upper surface of the co-permeable layer 16 can be considered as the upper surface of the insulating powder layer 12 without adhesive. In this embodiment, for example, an 8 mm thick calibration adhesive layer 15 forms a 6 mm thick co-permeable layer 16, i.e., L is taken as 6 mm.

[0028] In the above operation, the sample tube 11 completely simulates the actual electric heating tube 10, in order to ensure that the co-permeation layer 16 calibrated later can be consistent with the co-permeation layer 16 formed during the processing of the actual electric heating tube 10.

[0029] After the co-permeation layer 16 is calibrated, the custom lead-out rod 17 can be fabricated: as shown in the attached document. Figure 2 As shown, the top of the customized lead-out rod 17 has a first hollow section 170, and the first hollow section 170 has a first glue-dip hole 171. The lowest first glue-dip hole 171 is located above the bottom surface of the first hollow section 170, and the distance between the highest first glue-dip hole 171 and the lowest first glue-dip hole 171 is E, which satisfies E>L. The area between the bottom surface of the first hollow section 170 and the lowest first glue-dip hole 171 constitutes a first glue-storage pit 172.

[0030] The customized lead-out rod 17 is an improvement on the lead-out rod of a regular electric heating tube. The improvement lies in the presence of a hollow section, with a series of first glue-diffusion holes 171 continuously arranged along the height of the hollow section. Generally, the first glue-diffusion holes 171 are evenly distributed circumferentially on the hollow section, but the diameter of the first glue-diffusion holes 171 is generally small and the density is relatively low, in order to minimize the simultaneous seepage of a large amount of glue into the first glue storage pit 172.

[0031] In this embodiment, it is necessary to satisfy E > L, that is, the length of the area containing the first adhesive penetration hole 171 on the first hollow segment 170 must be greater than the thickness of the co-permeation layer 16, that is, at least E > 6 mm. Preferably, it is necessary to satisfy E ≥ L + 2 mm, that is, E ≥ 8 mm, so as to ensure that the first adhesive penetration hole 171 is provided in a sufficient number of areas.

[0032] Once the custom lead-out rod 17 is manufactured, it can be used in the processing and production of the heating element 10. During the processing and production of the heating element 10, the custom lead-out rod 17 is first inserted into the heating element 10: as shown in the attached diagram. Figure 3As shown, the bottom interface Q is marked in the insulating powder layer 12 according to the distance L in the heating tube 10. A custom lead-out rod 17 is inserted into the insulating powder layer 12 of the heating tube 10, ensuring that the highest first glue penetration hole 171 is lower than the upper surface of the insulating powder layer 12, and the lowest first glue penetration hole 171 is lower than the marked bottom interface Q. An insulating sheath 14 is wrapped around one end of the custom lead-out rod 17 using a heat-shrink process. The bottom end of the heat-shrink insulating sheath 14 is higher than the highest first glue penetration hole 171, and a gap D2 is formed between the bottom end of the heat-shrink insulating sheath 14 and the upper surface of the insulating powder layer 12. The gap D2 is equal to the gap D1.

[0033] In conjunction with the aforementioned steps, since the sample tube 11 completely simulates the actual heating element 10, in the actual production of the heating element 10, the bottom cross-section Q of the co-permeation layer 16 inside the heating element 10 can be calibrated on the heating element 10 according to L, with reference to the sample tube 11. That is, in this step, referring to the calibration of the co-permeation layer 16 in the sample tube 11, the co-permeation layer 16 of the heating element 10 actually being produced is calibrated: a distance L downward from the upper surface of the insulating powder layer 12 (L is taken as 6 mm in the previous text) is marked as the bottom interface Q of the co-permeation layer 16 that can be formed inside the heating element 10.

[0034] It should be noted that the gaps D2 and D1 in this embodiment are not intentionally set, but are naturally formed due to the heat shrinking process. Theoretically, for heating tubes 10 and 11 of the same specifications, when using insulating sleeves 14 of the same specifications, gaps D2 and D1 will naturally be equal. In this embodiment, a gap of 2 mm can be used as an example. For traditional heating tubes, one of the purposes of sealing the tube opening is to ensure that the gap between the insulating sleeve 14 and the insulating powder layer 12 is sealed within the adhesive, thereby ensuring the insulation effect.

[0035] Then mass production and gluing can begin: as shown in the attached document. Figure 3 As shown, glue is poured into the heating tube 10 to cover the gap D2 to form a sealing glue layer 18. The thickness of the sealing glue layer 18 is the same as that of the calibration glue layer 15. Some of the glue in the sealing glue layer 18 seeps into the insulating powder layer 12. The glue displaces the air between the insulating powders. The air can then escape to the atmosphere through the first glue penetration hole 171, or form bubbles and flow into the first glue storage pit 172 along with the glue passing through the first glue penetration hole 171.

[0036] In this step, the thickness of the sealing adhesive layer 18 is generally 8-10 mm. In this embodiment, it is 8 mm. The temperature of the injected adhesive is also set to 30-40℃.

[0037] In this step, as the adhesive is poured in, it will slowly seep into the gaps between the insulating powder particles. Over time, the adhesive will first seep down to the height of the first seepage hole 171 at the highest position, and then gradually seep down to a position no lower than the bottom interface Q.

[0038] On a finer level, as the adhesive seeps down, it also displaces the air between the insulating powders. Since the highest first adhesive penetration hole 171 is lower than the upper surface of the insulating powder layer 12 when the custom lead-out rod 17 is inserted into the insulating powder layer 12, and the lowest first adhesive penetration hole 171 is lower than the marked bottom interface Q, air can flow between the gaps between the insulating powders in the insulating powder layer 12 before the adhesive has soaked in it. Similarly, the displaced air can easily flow out from the first adhesive penetration hole 171 on the custom lead-out rod 17.

[0039] Meanwhile, compared to the flow resistance, the liquid pressure in the area where the glue is submerged is greater, meaning that the flow resistance of air penetrating into the glue is greater. However, the first glue penetration hole 171 is connected to the atmosphere, so the flow resistance is smaller. Therefore, during the glue penetration process, air can be preferentially discharged from the nearest first glue penetration hole 171.

[0040] In areas where the adhesive has already soaked into the insulating powder layer 12, some adhesive will inevitably flow out from the nearby first adhesive seepage hole 171 and fall into the first adhesive storage pit 172 at the bottom of the first hollow section 170. This adhesive seepage process occurs simultaneously with the aforementioned direct escape and discharge of air. (See attached...) Figure 4 As shown, when a small amount of air encounters a structural dead zone within the insulating powder layer 12, the adhesive may encapsulate the air, forming small closed air bubbles. As the adhesive overflows through the seepage holes, some adhesive carries some air bubbles with it, thus reducing the amount of air bubbles remaining inside the adhesive. It's important to understand that since the first adhesive storage pit 172 is located inside the lead-out rod, the presence of air bubbles within the first adhesive storage pit 172 does not affect the insulation performance of the product.

[0041] As the adhesive continues to seep down, it will gradually approach the previously marked bottom interface Q. However, the air expulsion process described above is also in progress. This is because the lowest first adhesive penetration hole 171 is lower than the marked bottom interface Q. Even if the adhesive has penetrated deep enough at this time, the expelled air can still be discharged through the lowest first adhesive penetration hole 171, or through a portion of the first adhesive penetration hole 171 that is not higher than the bottom interface Q.

[0042] Preferably, when inserting the custom lead-out rod 17 into the heating tube 10, it is best to ensure that a relatively large number of the first glue-dip holes 171 are below the marked bottom interface Q, rather than only the lowest first glue-dip hole 171 being below the marked bottom interface Q, thereby ensuring the venting effect.

[0043] It is important to note that although the amount of glue in the first glue storage pit 172 is constantly increasing, it will not submerge the lowest glue penetration hole, meaning it will not affect the venting process. This is because the first glue penetration hole 171 is located within the insulating powder layer 12. The glue needs to pass through the insulating powder before flowing through the first glue penetration hole 171. Furthermore, the density of the first glue penetration holes 171 is low, and their diameter is small. The glue can only flow into the first glue storage pit 172 in the form of "seepage." Additionally, the glue has high viscosity and a low flow rate, causing it to be continuously intercepted and mixed by the insulating powder. Therefore, the rate at which glue accumulates in the first glue storage pit 172 is very slow.

[0044] Furthermore, because the insulating powder is granular with a large specific surface area, the adhesive adheres to its surface after seeping in, forming a stable "adhesive film." This means the adhesive and insulating powder form a relatively stable mixture. As mentioned earlier, an 8 mm sealing adhesive layer 18 can form a 6 mm co-permeation layer 16. Additionally, some adhesive needs to seal a gap of approximately 2 mm, D2. Therefore, only "excess" adhesive can seep in, and the total amount of adhesive that can seep out of the seepage pores is very small.

[0045] In addition, although the glue has a relatively low viscosity and relatively good fluidity in the initial stage after it is poured in, and can easily seep out of the first glue hole, as time goes by, the glue will gradually become more and more viscous due to the curing reaction, and its adhesion to the insulating powder will further increase. The fluidity of the glue will continue to deteriorate, so the amount of glue seeping out through the first glue seepage hole 171 will gradually decrease.

[0046] Therefore, by appropriately increasing the depth of the first adhesive storage pit 172 and expanding its storage capacity when manufacturing the custom lead-out rod 17, it is possible to completely prevent the liquid level in the first adhesive storage pit 172 from reaching the lowest point of the first adhesive penetration hole 171 before the adhesive is fully cured. In a preferred embodiment, based on practical experience, when manufacturing the custom lead-out rod 17, the distance between the lowest point of the first adhesive penetration hole 171 and the bottom surface of the first hollow section 170 is greater than or equal to 2 mm, meaning that the highest liquid level in the first adhesive storage pit 172 is actually no greater than 2 mm.

[0047] After the above-mentioned batch production and glue-filling steps, as the glue gradually seeps in and solidifies, it completely solidifies and forms a seal.

[0048] In contrast, the solid lead-out rod used in the conventional glue-dipping method does not have a first glue penetration hole 171. The air squeezed out by the glue can only float up and penetrate into the glue because there is no first glue penetration hole 171 to connect with the atmosphere. As the glue gradually solidifies, it remains in the glue and forms pores with an internal porosity of 80% to 90%.

[0049] The method in this embodiment significantly reduces the bubble rate inside the glue after curing to only about 20% to 30%. The remaining bubbles exist in the area near the inner wall of the heating element 10. Since these areas are far from the custom lead-out rod 17, the gas exhaust resistance is relatively high.

[0050] Furthermore, at the end of the above steps, after the glue has solidified, a glue replenishment process can be performed: glue is poured into the first hollow section 170 until it covers the highest point of the first glue seepage hole 171. This step replenishes the glue in the first hollow section 170, raising the glue level in the first glue storage pit 172 so that it covers the area where the first glue seepage holes 171 are distributed, further consolidating the sealing of the area where the first glue seepage holes 171 are located.

[0051] Example 2

[0052] The glue-filling and sealing method for an electric heating tube in this embodiment can be improved as follows compared with the technical solution of Embodiment 1: After making the custom lead-out rod 17, the method further includes measuring and adjusting the depth of the first glue storage pit 172: the custom lead-out rod 17 is inserted into the sample tube 11 containing the insulating powder layer 12, and glue of the same thickness as the calibrated glue layer 15 is poured into the sample tube 11. The glue is allowed to seep down and solidify. After the glue in the sample tube 11 is completely solidified, the sample tube 11 and the custom lead-out rod 17 are cut open, the liquid level of the glue in the first glue storage pit 172 is measured and recorded, and the depth of the first glue storage pit 172 of the remaining custom lead-out rods 17 is adjusted according to the liquid level to ensure that the liquid level in the first glue storage pit 172 is lower than the lowest first glue penetration hole 171; wherein, the depth of the first glue storage pit 172 refers to the distance between the bottom surface of the first hollow section 170 of the custom lead-out rod 17 and the lowest first glue penetration hole 171.

[0053] Based on the description in Example 1 of the glue seeping through the first glue penetration hole 171 to the first glue storage pit 172, this example proposes the measurement and adjustment of the depth of the first glue storage pit 172. A complete simulation experiment in sample tube 11 can be used to determine the possible liquid level height within the first glue storage pit 172, and then the corresponding range of liquid level values ​​within the first glue storage pit 172 can be obtained. This allows for targeted adjustment of the bottom position of the first hollow section 170 in the customized lead-out rod 17, preventing the liquid level in the storage pit from exceeding the lowest point of the first glue penetration hole 171 during actual production, which would affect venting.

[0054] Example 3

[0055] Combined with appendix Figure 5 The potting and sealing method for an electric heating tube in this embodiment can be improved as follows compared with the technical solutions of Embodiment 1 or 2: after inserting the customized lead-out rod 17 into the electric heating tube 10, it further includes: making and inserting the air guide rod 19.

[0056] The process of making the air guide rod 19 includes: opening a second hollow section 190 at the top of the air guide rod 19, opening a second glue penetration hole 191 on the second hollow section 190, the lowest second glue penetration hole 191 being located above the bottom surface of the second hollow section 190, and the distance between the highest second glue penetration hole 191 and the lowest second glue penetration hole 191 being greater than L, and the area between the bottom surface of the second hollow section 190 and the lowest second glue penetration hole 191 forming a second glue storage pit 192.

[0057] Inserting the air guide rod 19 includes inserting the air guide rod 19 into the insulating powder layer 12 of the heating tube 10, ensuring that the highest second glue penetration hole 191 is lower than the upper surface of the insulating powder layer 12, while the lowest second glue penetration hole 191 is lower than the marked bottom interface Q.

[0058] Similar to the working principle of the customized lead-out rod 17 in Example 1, this embodiment can further utilize the second hollow section 190, the second glue penetration hole 191, and the second glue storage pit 192 opened on the air guide rod 19 to allow the air squeezed out during the glue penetration into the insulating powder to be discharged from the second glue penetration hole 191, thus preventing it from rushing into the sealing glue layer 18 and forming air bubbles, thereby affecting the insulation and sealing effect of the sealing glue layer 18.

[0059] It is conceivable that the arrangement of the second glue penetration hole 191, such as its pore size and density, and the depth of the second glue storage pit 192, should preferably be consistent with the arrangement of the first glue penetration hole 171 and the first glue storage pit 172.

[0060] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A method for pouring and sealing glue for an electrothermal tube, characterized in that, The method comprises the following steps: Preparation of the heating tube (10) and the sample tube (11): the heating tube (10) is prepared, and the sample tube (11) consistent with the structure of the heating tube (10) is prepared, and the insulation powder is filled in the heating tube (10) and the sample tube (11) to form an insulation powder layer (12); Insertion of the calibration lead rod (13) into the sample tube (11): the calibration lead rod (13) is prepared, inserted into the insulation powder layer (12) of the sample tube (11), and the insulation sheath (14) is wrapped on one end of the calibration lead rod (13) by heat shrinkage process, and the gap D1 is formed between the bottom end of the insulation sheath (14) after heat shrinkage and the upper surface of the insulation powder layer (12); Calibration of the co-permeation layer (16): the glue is poured into the sample tube (11) to form a calibration glue layer (15) which is higher than the gap D1, and the glue in part of the calibration glue layer (15) is infiltrated and mixed with the insulation powder to form a co-permeation layer (16); after the glue in the sample tube (11) is completely solidified, the sample tube (11) is cut open, and the distance between the bottom interface Q of the co-permeation layer (16) and the upper surface thereof is measured and recorded as L; Manufacture of the customized lead rod (17): the first hollow section (170) is formed on the top of the customized lead rod (17), the first glue infiltration hole (171) is formed on the first hollow section (170), the lowest first glue infiltration hole (171) is located above the bottom surface of the first hollow section (170), and the distance between the highest first glue infiltration hole (171) and the lowest first glue infiltration hole (171) is E, which satisfies E>L, and the region between the bottom surface of the first hollow section (170) and the lowest first glue infiltration hole (171) forms the first glue storage pit (172); Insertion of the customized lead rod (17) into the heating tube (10): the bottom interface Q is marked in the insulation powder layer (12) of the heating tube (10) according to the distance L, the customized lead rod (17) is inserted into the insulation powder layer (12) of the heating tube (10), the highest first glue infiltration hole (171) is ensured to be lower than the upper surface of the insulation powder layer (12), and the lowest first glue infiltration hole (171) is ensured to be lower than the marked bottom interface Q, and the insulation sheath (14) is wrapped on one end of the customized lead rod (17) by heat shrinkage process, the bottom end of the insulation sheath (14) after heat shrinkage is higher than the highest first glue infiltration hole (171), and the gap D2 is formed between the bottom end of the insulation sheath (14) after heat shrinkage and the upper surface of the insulation powder layer (12), which is equal to the gap D1; Batch glue pouring: the glue is poured into the heating tube (10) to form a sealing glue layer (18) which is higher than the gap D2, the thickness of the sealing glue layer (18) is consistent with that of the calibration glue layer (15), and the glue in part of the sealing glue layer (18) is infiltrated into the insulation powder layer (12), the glue expels the air between the insulation powder, the air escapes to the atmosphere through the first glue infiltration hole (171), or flows into the first glue storage pit (172) after forming bubbles and passing through the first glue infiltration hole (171); Glue solidification and molding: the glue in the heating tube (10) is waited to be fully solidified to complete the sealing.

2. The method for filling and sealing of an electric heating tube according to claim 1, characterized in that, After the glue solidification molding, the glue filling process is carried out: the glue is poured into the first hollow section (170) until the glue covers the highest first glue infiltration hole (171).

3. The method of claim 1, wherein the glue is injected into the gap between the electric heating tube and the sealing cover through the hole of the sealing cover. After the customized lead-out rod (17) is made, the first glue storage pit (172) depth is measured and adjusted: the customized lead-out rod (17) is inserted into the sample tube (11) containing the insulating powder layer (12), the glue with the same thickness as the calibrated glue layer (15) is poured into the sample tube (11), the glue is infiltrated and solidified, and when the sample tube (11) and the customized lead-out rod (17) are cut, the liquid level of the glue in the first glue storage pit (172) is measured and recorded, and the depth of the first glue storage pit (172) of the remaining customized lead-out rod (17) is adjusted according to the liquid level to ensure that the liquid level in the first glue storage pit (172) is lower than the lowest first glue infiltration hole (171); wherein the depth of the first glue storage pit (172) is the distance between the bottom surface of the first hollow section (170) of the customized lead-out rod (17) and the lowest first glue infiltration hole (171).

4. The method of claim 1, wherein the glue sealing is performed after the heating of the electric heating tube. When the customized lead-out rod (17) is made, the distance between the lowest first glue infiltration hole (171) and the bottom surface of the first hollow section (170) is greater than or equal to 2mm.

5. The glue-filling and sealing method of the electrothermal tube according to claim 1 or 3 or 4, characterized in that, After the customized lead-out rod (17) is inserted into the electric heating tube (10), the air guide rod (19) is made and inserted; The air guide rod (19) is made, including: a second hollow section (190) is opened at the top of the air guide rod (19), a second glue infiltration hole (191) is opened on the second hollow section (190), the lowest second glue infiltration hole (191) is located above the bottom surface of the second hollow section (190), and the distance between the highest second glue infiltration hole (191) and the lowest second glue infiltration hole (191) is greater than L, and the area between the bottom surface of the second hollow section (190) and the lowest second glue infiltration hole (191) constitutes a second glue storage pit (192); The air guide rod (19) is inserted, including: the air guide rod (19) is inserted into the insulating powder layer (12) of the electric heating tube (10), ensuring that the highest second glue infiltration hole (191) is lower than the upper surface of the insulating powder layer (12), and the lowest second glue infiltration hole (191) is lower than the marked bottom interface Q.

6. The method of claim 1, wherein the glue sealing is performed after the heating of the electric heating tube. When the customized lead-out rod (17) is inserted into the electric heating tube (10), part of the first glue infiltration hole (171) is lower than the marked bottom interface Q.

7. The method of claim 1, wherein the glue sealing is performed after the heating of the electric heating tube. The distance E between the highest first glue infiltration hole (171) and the lowest first glue infiltration hole (171) on the first hollow section (170) satisfies E≥L+2mm.

8. The method for potting and sealing an electric heating element according to claim 1, characterized in that, The thickness of the calibrated glue layer (15) and the sealing and pouring glue layer (18) is 8-10mm.

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