Electric heating tube sealing structure and sealing method

Abstract

The invention relates to the technical field of electric heating tube production and manufacturing, in particular to an electric heating tube sealing structure and a sealing method. Aiming at the problem that the existing electric heating tube sealing technology has defects, the electric heating tube sealing structure and the sealing method provided by the invention have the advantages that the distribution condition of holes and pits generated by glue filling is improved by utilizing the improvement of an insulating plug structure and the optimization of a sealing process, so that the sealing quality of the electric heating tube is improved. Therefore, the insulation performance and the sealing performance of the electric heating tube sealing structure are improved.

Description

Technical Field

[0001] The invention relates to the technical field of production and manufacturing of electric heating tubes, and in particular to an electric heating tube sealing structure and a sealing method. Background Art

[0002] In the manufacturing process of medium and high voltage electric heating tubes, sealing is an extremely critical process. On the one hand, only high-quality sealing can prevent moisture in the air from entering the interior of the electric heating tube, causing the electric heating tube to be affected by moisture and its pressure resistance to decrease. On the other hand, the lead-out rod and the electric heating tube wall also need to rely on sealing materials to ensure insulation between each other, because the insulation distance relying solely on air cannot provide insulation strength that meets medium and high voltage conditions.

[0003] In the current production process of electric heating tubes, organic potting glue is often used to seal the tube mouth. The operation steps are to mix the liquid glue and curing agent and drip it into the tube mouth, and then wait for it to slowly solidify and finally form a solid to obtain a higher insulation strength. However, since the insulating powder itself is a granular substance, there are air pores inside the insulating powder layer, so the glue tends to penetrate into the insulating powder layer, and the air in the pores will float up to form bubbles, and finally form holes or pits on the surface after the glue solidifies. On the one hand, the pits mean the lack of insulating glue, so that the insulation strength does not meet the product requirements. On the other hand, the holes will cause the sealing of the tube mouth to decrease, increasing the probability of air entering and getting damp. Summary of the invention

[0004] In view of the defects in the existing electric heating tube sealing technology, the present invention provides an electric heating tube sealing structure and a sealing method, which utilizes the improvement of the insulating plug structure to improve the distribution of holes and pits caused by glue injection, thereby improving the insulation performance and sealing performance of the electric heating tube sealing structure.

[0005] The technical solution provided by the present invention is: a sealing structure for an electric heating tube, comprising an electric heating tube and a lead-out rod, wherein the electric heating tube is filled with insulating powder to form an insulating powder layer, one end of the lead-out rod is covered with an insulating sheath, and part of the lead-out rod is inserted into the insulating powder layer, so that there is a gap between one end of the insulating sheath and the insulating powder layer; glue is poured on the surface of the insulating powder layer to form a first glue layer, and the thickness of the first glue layer is greater than the gap height; an insulating plug is provided on one side of the first glue layer, a through hole is provided at the center of the insulating plug, and through glue holes are evenly distributed around the through hole, the lead-out rod passes through the through hole, the glue hole is connected to the first glue layer, and at least part of the glue penetrates into the glue hole.

[0006] Optionally, a flared opening is provided on a side of the glue hole facing the first glue layer.

[0007] Optionally, the diameter of the glue hole is less than or equal to 1 / 16 of the diameter of the insulating plug.

[0008] Optionally, the glue hole diameter is less than or equal to 2 mm.

[0009] Optionally, the center distance between adjacent glue holes is 3 times the diameter of the glue holes.

[0010] Optionally, a side of the insulating plug facing away from the first glue layer is filled with glue to form a second glue layer, and the glue hole is connected to the second glue layer so that the glue of the second glue layer can penetrate into the glue hole.

[0011] Optionally, an outer diameter of the insulating plug is interference fit with an inner diameter of the electric heating tube.

[0012] A sealing method is used for the above-mentioned electric heating pipe sealing structure, comprising the following steps: inserting a lead-out rod: filling insulating powder in the electric heating pipe to form an insulating powder layer, wrapping an insulating sheath at one end of the lead-out rod by a heat shrink process, inserting part of the lead-out rod into the insulating powder layer, and retaining a gap between the bottom end of the insulating sheath and the insulating powder layer; pouring glue: pouring glue on the surface of the insulating powder layer, and the thickness of the poured glue is greater than the gap height between the bottom end of the insulating sheath and the insulating powder layer; placing an insulating plug: inserting the insulating plug from the top of the lead-out rod through a through hole, and moving it into the electric heating pipe until at least part of the insulating plug contacts the glue, and ensuring that the glue hole infiltrates the glue; solidification and molding: the glue infiltrates into the insulating powder layer during the slow solidification process, and the air in the pores of the insulating powder layer floats up to form bubbles, and the bubbles are discharged from the glue hole, or remain in the glue hole, so that when the glue is completely solidified to form a first glue layer, the holes or pits formed by the solidification of the bubbles are mainly retained in the glue hole.

[0013] Optionally, after the first glue layer is fully solidified, glue is poured onto the surface of the insulating plug to allow the glue to penetrate into the glue hole, fill the holes or pits in the glue hole, and then solidify to form a second glue layer.

[0014] Optionally, at least part of the insulating plug is pushed into contact with the glue by a pushing tool; wherein the pushing tool comprises a sleeve and a push rod, the push rod is fixed on the sleeve, and the end face of the sleeve is used to abut against the insulating plug.

[0015] Optionally, the sum of the heights of the push rod and the sleeve is greater than the depth of the insulating plug placed in the electric heating tube.

[0016] Beneficial Effects

[0017] The technical solution provided by the present invention has the following beneficial effects compared with the prior art: in view of the defects in the existing electric heating tube sealing technology, the present invention utilizes the improvement of the insulating plug structure to improve the distribution of holes and pits caused by glue injection, thereby improving the insulation performance and sealing performance of the electric heating tube sealing structure.

[0018] The insulating plug will remain in the electric heating tube after the glue solidifies and takes shape, which can reinforce and protect the tube mouth of the electric heating tube: Since the glue is highly brittle and has poor temperature resistance after solidification, the insulating plug can play a buffering and isolating protective role to prevent the solidified glue from breaking and cracking, or failing due to high temperature, thereby increasing the life of the sealing structure.

[0019] In addition, compared with the prior art, the provision of the insulating plug in the present technical solution is equivalent to replacing glue of a certain thickness with an insulating plug with better pressure resistance certainty, thereby improving the pressure resistance certainty of the electric heating tube product. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of an electric heating pipe sealing structure proposed in an embodiment of the present invention.

[0021] Figure 2 This is one of the structural schematic diagrams of the insulating plug proposed in an embodiment of the present invention.

[0022] Figure 3 This is the second structural schematic diagram of the insulating plug proposed in the embodiment of the present invention.

[0023] Figure 4 This is a schematic diagram of the “insertion and extraction rod” proposed in an embodiment of the present invention.

[0024] Figure 5 This is a schematic diagram of the “glue filling” proposed in an embodiment of the present invention.

[0025] Figure 6 This is a schematic diagram of “inserting an insulating plug” proposed in an embodiment of the present invention.

[0026] Figure 7 This is a schematic diagram of using a “pushing tool” proposed in an embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to further understand the content of the present invention, the present invention is described in detail in conjunction with the accompanying drawings and embodiments.

[0028] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are only used to explain the relevant inventions, rather than to limit the invention. It should also be noted that, for the convenience of description, only the parts related to the invention are shown in the accompanying drawings. The words "first", "second", etc. described in the present invention are set for the convenience of describing the technical solution of the present invention, and have no specific limiting effect. They are all general references and do not constitute a limiting effect on the technical solution of the present invention. It should be noted that, in the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. In the description of the present invention, it should be noted that the orientation or position relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. Unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be a connection between the insides of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. Multiple technical solutions in the same embodiment, and multiple technical solutions in different embodiments, can be arranged and combined to form new technical solutions without contradictions or conflicts, all of which are within the scope of protection required by the present invention.

[0029] Example 1

[0030] Combined with Figure 1-3 The present embodiment proposes an electric heating pipe sealing structure, including an electric heating pipe 1 and a lead-out rod 3, the electric heating pipe 1 is filled with insulating powder to form an insulating powder layer 4, one end of the lead-out rod 3 is covered with an insulating sheath 2, and part of the lead-out rod 3 is inserted into the insulating powder layer 4, so that there is a gap D between one end of the insulating sheath 2 and the insulating powder layer 4; glue is poured on the surface of the insulating powder layer 4 to form a first glue layer 51, and the thickness of the first glue layer 51 is greater than the height of the gap D; an insulating plug 10 is provided on one side of the first glue layer 51, and a through hole 6 is provided at the center of the insulating plug 10, and through glue holes 7 are evenly distributed around the through hole 6, the lead-out rod 3 passes through the through hole 6, the glue hole 7 is connected to the first glue layer 51, and at least part of the glue penetrates into the glue hole 7.

[0031] The advantage of the electric heating tube sealing structure of this embodiment is that when the glue injected on the surface of the insulating powder layer 4 has not yet solidified, the gravity of the glue itself and the gravity of the insulating plug 10 can be used to squeeze the glue, thereby increasing the pressure of the glue penetrating into the insulating powder layer 4, thereby helping the air in the pores of the insulating powder layer 4 to be replaced by the glue, and the bubbles formed by the replacement will be more easily floated and discharged due to the aforementioned pressure.

[0032] Furthermore, the discharged bubbles will not all accumulate in the first glue layer 51. As the glue flows into the glue hole 7, the actual liquid level of the glue is raised. According to the liquid pressure formula: P=ρgh, the liquid pressure in the first glue layer 51 is higher than the pressure in the glue hole 7, so it is easier for the bubbles to float up into the glue hole 7 rather than remain in the first glue layer 51. The bubbles can be discharged from the glue hole 7, or only remain in the glue hole 7. When the glue is completely solidified to form the first glue layer 51, the holes or pits formed by the solidification of the bubbles are mainly retained in the glue hole 7, thereby ensuring that there are no pits in the first glue layer 51, or only a small number of pits exist on the contact surface between the first glue layer 51 and the insulating plug 10. As a result, the electric heating pipe sealing structure of this embodiment achieves improved insulation and sealing properties.

[0033] The insulating plug 10 in this embodiment is preferably made of an elastic material such as soft silicone, which can prevent the inner wall of the electric heating tube 1 from being scratched. At the same time, the material has insulation properties and can withstand the electrical strength between the lead-out rod 3 and the wall of the electric heating tube 1. In addition, the outer diameter of the insulating plug 10 and the inner diameter of the electric heating tube 1 are preferably interference fit. This can provide better fit and sealing and higher friction, so that the insulating plug 10 can fully fit the inner wall of the electric heating tube 1.

[0034] In a preferred embodiment, the glue hole 7 is provided with a flare 13 on one side facing the first glue layer 51. When the bottom of the glue hole 7 is the flare 13, it can guide the bubbles to float upward, which is beneficial for the glue hole 7 to capture the bubbles, thereby facilitating the bubbles to enter the glue hole 7.

[0035] The glue holes 7 in this embodiment should be as small and dense as possible. In a preferred embodiment, the diameter of the glue holes 7 is less than or equal to 2 mm, and the diameter of the glue holes 7 is less than or equal to 1 / 16 of the diameter of the insulating plug 10. The purpose of this embodiment is to avoid the diameter of the glue holes 7 being too large, which will affect the strength of the insulating plug 10 itself, and to avoid the insulating plug 10 and the side wall of the electric heating tube 1 not being closely attached. At the same time, it also ensures that the actual contact area between the insulating plug 10 and the glue is relatively large, so that it can be well bonded after solidification.

[0036] And, in other embodiments, the center distance between adjacent glue holes 7 is 3 times the diameter of the glue holes 7. This embodiment ensures the density of the glue holes 7. The densely distributed glue holes 7 are to ensure that the floating bubbles can find a glue hole 7 nearby, because from a microscopic level, the surface of the insulating plug 10 is not flat, and if the bubbles come into contact with the uneven surface after floating, they may be "stuck", so it is necessary to ensure the density of the glue holes 7 to ensure that the bubbles can overflow through the glue holes 7 nearby.

[0037] In combination with the above description, it can be known that since bubbles may still remain in the glue hole 7 after the glue solidifies, forming pits or holes in the glue hole 7, in an improved embodiment, the side of the insulating plug 10 away from the first glue layer 51 is filled with glue to form a second glue layer 52, and the glue hole 7 is connected to the second glue layer 52, so that the glue in the second glue layer 52 can penetrate into the glue hole 7. By providing the second glue layer 52, the pits and holes in the glue hole 7 can be further filled, thereby further improving the insulation performance and sealing performance of the electric heating pipe sealing structure.

[0038] Example 2

[0039] Combined with Figure 1-7 This embodiment further proposes a sealing method for the electric heating pipe sealing structure proposed in Embodiment 1, comprising the following steps: (1) Insert the lead rod 3: Combine with the attached Figure 4 Insulating powder is filled in the electric heating tube 1 to form an insulating powder layer 4, and an insulating sheath 2 is wrapped at one end of the lead rod 3 by a heat shrink process, and a part of the lead rod 3 is inserted into the insulating powder layer 4, and a gap D is reserved between the bottom end of the insulating sheath 2 and the insulating powder layer 4. The selection basis of the material and thickness of the insulating sheath 2 is: it can withstand the electrical strength between the lead rod 3 and the wall of the electric heating tube 1 to ensure the product voltage resistance requirements.

[0040] (2) Glue filling: Combined with the Figure 5 , glue is poured on the surface of the insulating powder layer 4, and the thickness of the poured glue is greater than the height of the gap D between the bottom end of the insulating sheath 2 and the insulating powder layer 4. Based on the existing sealing technology of the electric heating tube 1, when the insulating sheath 2 shrinks during heat shrinkage, a certain length (about 1 to 2 mm) of the lead rod 3 exposed part will naturally be formed at the bottom of the insulating sheath 2 near the insulating powder layer 4. In order to prevent this part from being exposed to the air, a certain thickness of glue needs to be poured on the surface of the insulating powder layer 4 to fill the exposed part to ensure that no electricity is transmitted.

[0041] (3) Insert the insulating plug 10: Combine with the attached Figure 6 The insulating plug 10 is inserted from the top of the lead-out rod 3 through the through hole 6 and moved into the electric heating tube 1 until at least part of the insulating plug 10 contacts the glue and the glue hole 7 is ensured to be infiltrated with glue.

[0042] In a preferred embodiment, at least part of the insulating plug 10 can be pushed into contact with the glue by pushing the tool. Figure 7 The push tool comprises a sleeve 9 and a push rod 8. The push rod 8 is fixed on the sleeve 9. The end surface of the sleeve 9 is used to abut against the insulating plug 10. The operator can easily apply a downward thrust to the insulating plug 10 through the push rod 8, and can precisely control the pushing distance through the push tool. By extending the push tool into the electric heating tube 1 to push the insulating plug 10 downward, it can be ensured that the operator does not touch the lead-out rod 3, thereby avoiding deformation of the lead-out rod 3.

[0043] In a further preferred embodiment, the sum of the heights of the push rod 8 and the sleeve 9 is greater than the depth of the insulating plug 10 placed in the electric heating tube 1. The purpose is to prevent the operator's hand from reaching into the electric heating tube 1 as much as possible to avoid bringing in impurities, and to prevent the operator from touching the lead-out rod 3 as much as possible to cause deformation of the lead-out rod 3.

[0044] When the insulating plug 10 is pushed to contact with the glue, the glue can be further squeezed by the pushing tool so that part of the glue flows upward into the glue hole 7, and then the pushing tool can be removed.

[0045] (4) Solidification and molding: The glue seeps into the insulating powder layer 4 during the slow solidification process, and the air in the pores of the insulating powder layer 4 floats up to form bubbles. The bubbles are discharged from the glue holes 7 or remain in the glue holes 7. When the glue is completely solidified to form the first glue layer 51, the holes or pits formed by the solidification of the bubbles are mainly retained in the glue holes 7.

[0046] At this stage, since the insulating powder itself is a granular substance, and the insulating powder layer 4 has air pores inside, the glue will slowly penetrate into the insulating powder layer 4, and the glue in the glue hole 7 will drop in level to fill the part of the glue that has penetrated, so that the insulating powder layer 4 and the insulating plug 10 are always filled with glue. In addition, as the glue penetrates into the pores inside the insulating powder layer 4, the air in the pores floats up to form bubbles. Under the action of buoyancy and the blocking effect of the insulating plug 10, most of the bubbles will drill into the glue hole 7 and eventually be discharged from the glue hole 7, and will not stay inside the first glue layer 51 or the contact surface between the first glue layer 51 and the insulating plug 10. Therefore, after the glue is finally solidified, most of the holes and pits formed by the solidification of the bubbles will appear in the glue hole 7, and the first glue layer 51 will be in a good state with no or very few holes inside and on the surface, thereby ensuring the insulation and sealing properties of the product.

[0047] Furthermore, combined with Figure 1After stage (4), that is, when the first glue layer 51 is fully solidified, glue can be poured on the surface of the insulating plug 10 to allow the glue to penetrate into the glue hole 7, fill the holes or pits in the glue hole 7, and then solidify to form a second glue layer 52, thereby forming a composite structure of "first glue layer 51-insulating plug 10-second glue layer 52", which can further enhance the sealing and insulation performance of the pipe mouth and further improve the product yield.

[0048] In summary, in combination with Example 1 and Example 2, it can be seen that in order to address the problem of defects in the existing electric heating tube sealing technology, the present technical solution utilizes the structure of the insulating plug 10 and the design of the glue hole 7 so that the bubbles or pits generated during the glue solidification and molding stage are minimized in the first glue layer 51 or on the contact surface between the insulating plug 10 and the first glue layer 51, but are distributed in the glue hole 7, thereby improving the distribution of holes and pits generated by glue pouring, thereby improving the insulation performance and sealing performance of the electric heating tube sealing structure.

[0049] In addition, the insulating plug 10 of this embodiment will remain in the electric heating tube 1 after the glue is solidified and formed, so as to reinforce and protect the tube mouth of the electric heating tube 1: since the glue is highly brittle and has poor temperature resistance after solidification, the insulating plug 10 can play a buffering and isolating protective role to prevent the solidified glue from being damaged and cracked, or failing due to high temperature, thereby increasing the life of the sealing structure.

[0050] In addition, compared with the prior art, the provision of the insulating plug 10 in the present technical solution is equivalent to replacing glue of a certain thickness with an insulating plug 10 with better pressure resistance certainty, thereby improving the pressure resistance certainty of the electric heating tube 1 product.

[0051] Example 3

[0052] Combined with Figure 1-7 On the basis of Example 2, this embodiment specifically proposes an example of a sealing method for an electric heating tube 1. In this example, the specifications of the electric heating tube 1 are: inner diameter 20 mm, and the diameter of the lead rod 3 is 4 mm. Therefore, the distance between the lead rod 3 and the inner wall of the electric heating tube 1 is 8 mm, that is, the conductive distance from the lead rod to the wall of the electric heating tube 1 is 8 mm.

[0053] Combined with Figure 4 First, the electric heating tube 1 is prepared for glue filling, that is, insulating powder is filled in the electric heating tube 1 to form an insulating powder layer 4, and the insulating sheath 2 is wrapped at one end of the lead-out rod 3 by a heat shrink process, and a part of the lead-out rod 3 is inserted into the insulating powder layer 4. In this example, the height of the gap D between the bottom end of the insulating sheath 2 and the insulating powder layer 4 is 1 to 2 mm, and the bottom of the insulating layer is about 20 mm deep from the pipe mouth.

[0054] Combined with Figure 5, glue filling preparation is completed. When the electric heating tube 1 is ready for glue filling, an appropriate amount of 30~40℃ glue is poured into the electric heating tube 1. The glue thickness (height) in the electric heating tube 1 is required to be about 8mm, so that it can cover the 1~2mm part of the bottom of the insulating sheath 2 that is not wrapped.

[0055] Combined with Figure 6 , prepare an insulating plug 10 with a thickness of 8 mm, insert it from the top of the lead-out rod 3, and then slowly move it down to contact the tube mouth of the electric heating tube 1.

[0056] Combined with Figure 7 , and then use a pushing tool to apply a thrust to the insulating plug 10, and precisely control the pushing distance, and push the insulating plug 10 slowly and accurately from the pipe mouth until it contacts the glue, specifically, push the insulating plug 10 to a distance of 46mm from the insulating powder layer. At this time, it means that 2mm thick glue is reversely squeezed into the glue hole 7 of the insulating plug 10, so that the glue hole 7 is just completely filled. Therefore, at this time, the height of the liquid level column in the glue hole 7 is the thickness of the insulating plug 10, 8mm.

[0057] Wait for the glue to solidify; during the solidification process, the glue will slowly seep into the gaps between the particles inside the insulating powder layer 4, and at the same time, the liquid level of the glue in the glue hole 7 will gradually decrease, that is, it is used to supplement the infiltrated glue. In this process, the air between the particles floats up to form bubbles and flows into the glue hole 7.

[0058] Finally, wait for 24 hours for the glue to completely solidify. At this time, the 8mm high liquid level in the glue hole 7 drops to about 4mm high, and the air holes or air pits formed by the bubbles remain in the glue hole 7.

[0059] At this time, the effective glue thickness is "6mm between the insulating powder and the insulating plug 10 (i.e., the thickness of the first glue layer 51)" and "4mm in the glue hole 7", which is about 10mm in total. This effective thickness is greater than or equal to "8mm conductive distance from the lead-out rod 3 to the inner wall of the electric heating tube 1", which can ensure that the "1-2mm lead-out rod 3 not wrapped in the sheath" will not conduct electricity to any part of the wall of the electric heating tube 1.

[0060] Through the operation of this embodiment, the pressure resistance yield of the product after glue filling is detected to reach 95%~96%, which means that the porosity of the 6mm thick glue layer (i.e., the first glue layer 51) that is in direct contact with the insulating powder is only 4%~5%, and it can be considered that it will basically not be affected by bubbles. It can be understood that when the first glue layer 51 is solidified, the bubbles all go to the glue holes 7.

[0061] In contrast, the conventional method directly injects 8mm deep glue without using the insulating plug 10 of the technical solution, and the bubble rate is as high as 30%. Therefore, the technical solution reduces the bubble rate of the glue layer and improves the pressure resistance yield rate.

[0062] Furthermore, combined with Figure 1 After solidification, a thin layer of glue is applied again on the surface of the insulating plug 10 to fill the gap in the glue hole 7. The glue on the surface of the insulating plug 10 solidifies and forms a second glue layer 52. The sealing structure of the electric heating pipe forms a composite structure of "first glue layer 51-insulating plug 10-second glue layer 52", which can further enhance the sealing and insulation performance of the pipe mouth and increase the yield rate to 97%, that is, further improve the yield rate of the product.

[0063] The present invention and its embodiments are described schematically above, and the description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by it and designs a structural method and an embodiment similar to the technical solution without creativity without departing from the purpose of the invention, they shall all fall within the protection scope of the present invention.

Claims

1. An electric heating tube sealing structure, comprising an electric heating tube (1) and a lead-out rod (3), characterized in that: The electric heating tube (1) is filled with insulating powder to form an insulating powder layer (4); one end of the lead-out rod (3) is covered with an insulating sheath (2); a portion of the lead-out rod (3) is inserted into the insulating powder layer (4) so ​​that a gap D exists between one end of the insulating sheath (2) and the insulating powder layer (4); The surface of the insulating powder layer (4) is filled with glue to form a first glue layer (51), and the thickness of the first glue layer (51) is greater than the height of the gap D; An insulating plug (10) is provided on one side of the first glue layer (51), a through hole (6) is provided at the center of the insulating plug (10), and through glue holes (7) are evenly distributed around the through hole (6). The lead-out rod (3) passes through the through hole (6), and the glue hole (7) is connected to the first glue layer (51), and at least part of the glue penetrates into the glue hole (7).

2. The electric heating pipe sealing structure according to claim 1, characterized in that: A flared opening (13) is provided on a side of the glue hole (7) facing the first glue layer (51).

3. The electric heating pipe sealing structure according to claim 1, characterized in that: The diameter of the glue hole (7) is less than or equal to 1 / 16 of the diameter of the insulating plug (10).

4. The electric heating pipe sealing structure according to claim 1 or 3, characterized in that: The diameter of the glue hole (7) is less than or equal to 2 mm.

5. The electric heating pipe sealing structure according to claim 1, characterized in that: The center distance between adjacent glue holes (7) is 3 times the diameter of the glue holes (7).

6. The electric heating pipe sealing structure according to claim 1, characterized in that: The side of the insulating plug (10) facing away from the first glue layer (51) is filled with glue to form a second glue layer (52), and the glue hole (7) is connected to the second glue layer (52) so that the glue in the second glue layer (52) can penetrate into the glue hole (7).

7. The electric heating pipe sealing structure according to claim 1, characterized in that: The outer diameter of the insulating plug (10) is interference-fitted with the inner diameter of the electric heating tube (1).

8. A sealing method, used for the electric heating pipe sealing structure according to any one of claims 1 to 7, characterized in that: The following steps are involved: Inserting the lead-out rod (3): filling the electric heating tube (1) with insulating powder to form an insulating powder layer (4), wrapping an insulating sheath (2) at one end of the lead-out rod (3) by a heat shrink process, and partially inserting the lead-out rod (3) into the insulating powder layer (4), with a gap D being retained between the bottom end of the insulating sheath (2) and the insulating powder layer (4); Glue pouring: pouring glue on the surface of the insulating powder layer (4), wherein the thickness of the poured glue is greater than the height of the gap D between the bottom end of the insulating sheath (2) and the insulating powder layer (4); Inserting the insulating plug (10): inserting the insulating plug (10) from the top of the lead-out rod (3) using the through hole (6), and moving it into the electric heating tube (1) until at least part of the insulating plug (10) contacts the glue, and ensuring that the glue penetrates into the glue hole (7); Solidification molding: During the slow solidification process, the glue seeps into the insulating powder layer (4), and the air in the pores of the insulating powder layer (4) floats up to form bubbles, which are discharged from the glue holes (7) or remain in the glue holes (7), so that when the glue is completely solidified to form the first glue layer (51), the holes or pits formed by the solidification of the bubbles are mainly retained in the glue holes (7).

9. A sealing method according to claim 8, characterized in that: When the first glue layer (51) is fully solidified, glue is poured onto the surface of the insulating plug (10) so that the glue penetrates into the glue hole (7), fills the holes or pits in the glue hole (7), and then solidifies to form a second glue layer (52).

10. A sealing method according to claim 8, characterized in that: At least a portion of the insulating plug (10) is pushed into contact with the glue by means of a pushing tool; wherein the pushing tool comprises a sleeve (9) and a push rod (8), the push rod (8) is fixed on the sleeve (9), and the end surface of the sleeve (9) is used to abut against the insulating plug (10).

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