End face flange sealing structure and oil-immersed transformer

Abstract

The invention discloses an end face flange sealing structure and an oil-immersed transformer, and belongs to the technical field of electrical equipment sealing. The sealing device comprises a first flange, a second flange, an elastic sealing ring and a plurality of threaded connecting pieces, the first flange and the second flange elastically clamp the elastic sealing ring, and a first gap is reserved between the first flange and the second flange; the threaded connecting piece is arranged on the first flange in a penetrating mode from top to bottom, the threaded connecting piece is connected with the first flange in a clamped mode, and the threaded connecting piece is connected with the first flange in a self-rotating mode; the threaded connecting piece is in threaded connection with the second flange, a second gap is reserved between the threaded connection end of the threaded connecting piece and the bottom of the threaded connection hole of the second flange, and the second gap is not smaller than the first gap; the threaded connection of the threaded connecting piece adjusts the size of the first gap so that the first flange and the second flange can clamp or loosen the elastic sealing ring. The first flange and the second flange can extrude the elastic sealing ring which is deformed permanently again to compensate for an aged damaged part, the resealing effect is good, and the maintenance difficulty is low.

Description

Technical Field

[0001] The invention relates to the technical field of electrical equipment sealing, and in particular to an end face flange sealing structure and an oil-immersed transformer. Background Art

[0002] Transformer is an indispensable electrical equipment in the power system. It undertakes the important purpose of transmitting and distributing electricity. Oil-immersed transformer is the most widely used transformer. The transformer oil used in oil-immersed transformer is used as cooling and insulating medium. It can fill the bubbles in the transformer and prevent the infiltration of gas to ensure the sealing of the transformer. It also plays a cooling role in the operation process of the transformer. The safe and reliable operation of oil-immersed transformer is a common issue faced by power companies today. The leakage of transformer oil during operation has always been a difficult problem for oil-immersed transformers. The leakage of transformer oil will not only cause environmental problems, but also endanger the service life of the transformer. In severe cases, it may cause insulation breakdown, short circuit, burning or even explosion, which will bring hidden dangers to the power safety of power users.

[0003] In order to ensure the sealing of the end face flange connection, a rubber sealing ring is usually installed between the connection surfaces. After a certain period of use, the rubber sealing ring will more or less permanently deform and lose some of its elasticity, resulting in reduced sealing performance. Traditional end face flange connections, when encountering such leakage, generally use electric welding or quick sealing glue sticks to plug the leak. Although this method can achieve sealing, the method is costly and greatly increases the difficulty of subsequent maintenance and disassembly of the flange. Summary of the invention

[0004] The invention provides an end face flange sealing structure and an oil-immersed transformer, which are used to solve the problems in the prior art of poor flange sealing and great maintenance difficulty after the sealing ring is deformed and aged.

[0005] In a first aspect, an embodiment of the present invention provides an end face flange sealing structure, comprising: a first flange, a second flange, an elastic sealing ring and a plurality of threaded connectors;

[0006] The first flange and the second flange elastically clamp the elastic sealing ring, and a first gap is left between the first flange and the second flange;

[0007] The threaded connector is disposed on the first flange from top to bottom, the threaded connector is clamped with the first flange, and the threaded connector is connected to the first flange in a rotatable manner;

[0008] The threaded connector is threadedly connected to the second flange, a second gap is left between the threaded end of the threaded connector and the bottom of the threaded hole of the second flange, and the second gap is not smaller than the first gap;

[0009] The threaded connection of the threaded connector is used to adjust the size of the first gap so that the first flange and the second flange can clamp or loosen the elastic sealing ring.

[0010] In some embodiments of the first aspect, the threaded connector includes a bolt and a capping block;

[0011] The first flange is provided with a cover through hole;

[0012] One end of the bolt is screwed into the screw hole, and the other end of the bolt passes through the cover through hole and is connected to the top pressing block;

[0013] The bolt has a step, the first flange is mounted on the step, and the top block and the step clamp the first flange.

[0014] In some embodiments of the first aspect, step surfaces of the plurality of steps are maintained on the same horizontal plane.

[0015] In some embodiments of the first aspect, the capping block is a nut;

[0016] The nut is threadedly connected to the bolt, and the relative movement caused by the rotation of the nut and the rotation of the bolt in the threaded hole is used to locate the position of the first flange.

[0017] In some embodiments of the first aspect, the bolt includes a wide-diameter stud and a narrow-diameter stud connected to each other;

[0018] The step is formed between the wide-diameter stud and the narrow-diameter stud;

[0019] The wide-diameter stud is screwed into the screw-connecting hole, the narrow-diameter stud passes through the cover through hole, and the top pressing block is connected to the narrow-diameter stud.

[0020] In some embodiments of the first aspect, the length of the wide-diameter stud is smaller than the hole depth of the screw hole, and the length of the narrow-diameter stud is larger than the hole depth of the cover through hole.

[0021] In some embodiments of the first aspect, the distance of the first gap is 0-5% of the height of the elastic sealing ring.

[0022] In some embodiments of the first aspect, the second flange is provided with an annular groove, and the elastic sealing ring is provided in the annular groove;

[0023] The first flange is provided with an annular protrusion, the annular protrusion is inserted into the annular groove, and the annular protrusion and the annular groove clamp the elastic sealing ring.

[0024] In some embodiments of the first aspect, a protrusion height of the annular protrusion is smaller than a groove depth of the annular groove.

[0025] In a second aspect, an embodiment of the present invention provides an oil-immersed transformer, comprising: a winding, an oil tank, an insulating bushing, and an end face flange sealing structure;

[0026] The winding is arranged in the oil tank, the oil tank is sealedly connected to the insulating sleeve, and the end face flange sealing structure is connected to the insulating sleeve.

[0027] It can be seen from the above technical solutions that the present invention has the following advantages:

[0028] 1. An embodiment of the present invention provides an end face flange sealing structure, comprising: a first flange, a second flange, an elastic sealing ring and a plurality of threaded connectors; the first flange and the second flange elastically clamp the elastic sealing ring, and a first gap is left between the first flange and the second flange; the threaded connector is arranged on the first flange from top to bottom, the threaded connector is clamped with the first flange, and the threaded connector is connected to the first flange in a rotatable manner; the second flange has a threaded hole, the threaded connector is threaded with the second flange, a second gap is left between the threaded end of the threaded connector and the bottom of the threaded hole, and the second gap is larger than the first gap; the threading of the threaded connector is used to adjust the size of the first gap, so that the first flange and the second flange clamp or loosen the elastic sealing ring, when the elastic sealing ring is aged, the threaded connector can be twisted to make the threaded connector screw deeper, compress the first gap, and make the first flange and the second flange further squeeze the elastic sealing ring that has been permanently deformed, compensate for the aging and damaged parts, so that the sealing effect can still be guaranteed at the connection between the two flanges, and the resealing operation and structure are very simple, and the maintenance difficulty is low.

[0029] 2. An embodiment of the present invention provides an oil-immersed transformer, comprising: a winding, an oil tank, an insulating bushing and an end face flange sealing structure; the winding is arranged in the oil tank, the oil tank is sealed and connected to the insulating bushing, and the end face flange sealing structure is connected to the insulating bushing, so when it is used, the end face flange sealing structure can ensure the sealed connection between the insulating bushing and the oil tank, thereby ensuring that the transformer oil will not leak from the oil tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative labor.

[0031] Figure 1A schematic diagram of the overall structure of an end face flange sealing structure provided by the first aspect of an embodiment of the present invention;

[0032] Figure 2 A schematic cross-sectional view of the overall structure of an end face flange sealing structure provided in the first aspect of an embodiment of the present invention;

[0033] Figure 3 A schematic cross-sectional view of a partial structure of an end face flange sealing structure provided in the first aspect of an embodiment of the present invention;

[0034] Figure 4 A schematic cross-sectional view of a first flange of an end face flange sealing structure provided in a first aspect of an embodiment of the present invention;

[0035] Figure 5 A schematic cross-sectional view of a second flange of an end face flange sealing structure provided by the first aspect of an embodiment of the present invention;

[0036] Figure 6 A schematic cross-sectional view of bolts of an end face flange sealing structure provided in accordance with a first aspect of an embodiment of the present invention.

[0037] Reference numerals:

[0038] 1. First flange; 10. Cover through hole; 11. Annular protrusion; 2. Second flange; 20. Screw hole; 21. Annular groove; 3. Elastic sealing ring; 4. Threaded connector; 40. Bolt; 400. Wide-diameter stud; 401. Narrow-diameter stud; 402. Step; 41. Top block; 5. First gap; 6. Second gap. DETAILED DESCRIPTION

[0039] The embodiments of the present invention provide an end face flange sealing structure and an oil-immersed transformer, which are used to solve the problems in the prior art of poor flange sealing and great maintenance difficulty after the sealing ring is deformed and aged.

[0040] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] See also Figures 1 to 6 , an end face flange sealing structure provided by the present invention comprises a first flange 1, a second flange 2, an elastic sealing ring 3 and a plurality of threaded connectors 4;

[0042] The first flange 1 and the second flange 2 elastically clamp an elastic sealing ring 3, and a first gap 5 is left between the first flange 1 and the second flange 2;

[0043] The threaded connector 4 is passed through the first flange 1 from top to bottom, the threaded connector 4 is clamped with the first flange 1, and the threaded connector 4 is connected to the first flange 1 in a rotatable manner;

[0044] The threaded connector 4 is threadedly connected to the second flange 2, and a second gap 6 is left between the threaded end of the threaded connector 4 and the bottom of the threaded hole 20 of the second flange 2. The second gap 6 is not smaller than the first gap 5. The second gap 6 is used to provide sufficient movement space for the first flange 1.

[0045] The threaded connection of the threaded connector 4 is used to adjust the size of the first gap 5 so that the first flange 1 and the second flange 2 can clamp or loosen the elastic sealing ring 3 .

[0046] The working principle of this solution is as follows: the threaded connector 4 can rotate in the first flange 1 and the threaded hole 20, and the threaded connector 4 is clamped with the first flange 1. Therefore, after the threaded connector 4 is threaded in the threaded hole 20 to produce axial displacement, it can drive the first flange 1 to move closer to or farther from the second flange 2, thereby adjusting the size of the first gap 5, and then adjusting the clamping force of the elastic sealing ring 3 between the first flange 1 and the second flange 2.

[0047] From the above principle, it can be known that if the elastic sealing ring 3 does not undergo permanent deformation, the threaded connector 4 is controlled to drive the first flange 1 and the second flange 2 to elastically clamp the elastic sealing ring 3; if the elastic sealing ring 3 undergoes permanent deformation after being clamped for a period of time, the threaded connector 4 is controlled to be screwed deeper to move the first flange 1 closer to the second flange 2, compressing the size of the first gap 5, so that the elastic sealing ring 3 is further squeezed by the first flange 1 and the second flange 2, compensating for the aging and damaged areas, thereby sealing the connection between the two flanges, with good sealing effect and simple resealing operation.

[0048] Compared with the prior art, the present solution has the following advantages: first, the sealing effect is good. Before the elastic sealing ring 3 is aged, the connection method of the first flange 1 and the second flange 2 of the present solution can achieve good sealing. Even after the elastic sealing ring 3 is aged and permanently deformed, the first flange 1 and the second flange 2 can be driven to further squeeze the elastic sealing ring 3 by adjusting the threaded depth of the threaded connector 4, so as to compensate for the aged or broken parts and ensure the sealing effect between the flanges; second, the resealing operation is simple and the maintenance is convenient. By twisting the threaded connector 4, the elastic sealing ring 3 can be recompressed, and there is no need to use the traditional methods of plugging leaks with electric welding or quick sealing glue sticks, which reduces the cost, is simple to operate, and is convenient to maintain; third, the structure is simple. The present solution only needs to use the above-mentioned threaded connector 4 to achieve the recompression of the elastic sealing ring 3, and no other additional structures need to be configured, which is simple and practical; fourth, the applicability is strong. Based on the current solution, it is only necessary to replace the ordinary thread with the threaded connector 4 of the above-mentioned solution, so that the threaded connector 4 can be clamped with the flange and rotatably connected to the flange, so as to achieve the effect of the present solution, which has strong applicability.

[0049] As a possible example, Figure 2 and Figure 3 As shown, this embodiment further provides a possible clamping structure between the threaded connector 4 and the first flange 1, the threaded connector 4 includes an end bolt 40 and a pressure top block 41; the first flange 1 is provided with a cover body through hole 10; one end of the bolt 40 is screwed into the screw hole 20, the bottom of the screw hole 20 and the bottom of the bolt 40 form a second gap 6, the other end of the bolt 40 passes through the cover body through hole 10 and is connected with the pressure top block 41; the bolt 40 has a step 402, the first flange 1 is mounted on the step 402, the step 402 surface of the step 402 is in abutment with the adjacent end surface of the first flange 1, the pressure top block 41 and the step 402 clamp the first flange 1, after adopting this setting mode, the threaded connector 4 can be clamped in the first flange 1, and the threaded connector 4 can rotate in the first flange 1, the threaded connector 4 can rotate in the screw hole 20 on the one hand, and can drive the first flange 1 to move on the other hand, providing a structural basis for re-compressing the elastic sealing ring 3.

[0050] In a specific embodiment, Figure 3 As shown, the present embodiment further provides a possible structure of the top block 41, which is a nut; the nut is threadedly connected to the bolt 40, and the rotation of the nut and the rotation of the bolt 40 in the threaded hole 20 cause the relative movement to locate the position of the first flange 1. When the elastic sealing ring 3 is further compressed, the pre-adjustment distance can be set as needed, and then each bolt 40 is threadedly rotated until the axial displacement is the pre-adjustment distance, and then the first flange 1 is pressed against the step 402, and then the position of each nut is adjusted so that the first flange 1 is clamped and fixed by the nut and the step 402.

[0051] After adopting the above structure, the threaded connector 4 can provide a suitable pre-adjustment distance for the first flange 1 to adapt to the adjustment of the first flange 1 under different wear conditions. For example, when the end face of the first flange 1 is intact and the end face of the first flange 1 needs to be closer to the end face of the second flange 2, the pre-adjustment distances at various points on the end face of the entire first flange 1 are the same, and it is only necessary to control the axial displacements of various bolts 40 to be the same. Then, the first flange 1 is moved as a whole and fixed with nuts to ensure that the first flange 1 is moved into place while reducing the wear of the first flange 1 caused by local movement. For another example, when the end faces of the first flange 1 and / or the second flange 2 are worn and partially tilted, the end face of the first flange 1 needs to be closer to the end face of the second flange 2. In order to ensure that the distances between various points on the end face of the first flange 1 and various points on the end face of the second flange 2 are the same everywhere, the pre-adjustment distances of various points are different at this time, and the axial displacements of various bolts 40 are controlled according to the pre-adjustment distances to make the distances between various points on the first flange 1 and the second flange 2 the same.

[0052] In some other specific embodiments, Figure 2 and Figure 3 As shown, the present embodiment further provides a possible structure of the top block 41. The top block 41 is not a nut, but a block fixedly welded to the other end of the bolt 40. After adopting this arrangement, it can also cooperate with the step 402 to clamp the first flange 1, and does not affect the rotation of the bolt 40, thereby realizing the adjustment of the size of the first gap 5. However, each rotation adjustment of the bolt 40 in the threaded hole 20 will simultaneously drive the first flange 1 to move. Since it is impossible to complete the rotation of each threaded connector 4 at the same time, the first flange 1 is prone to move locally first and is prone to wear. Therefore, the present embodiment is provided as a possible solution for reference by those skilled in the art.

[0053] As a possible example, Figure 2 , Figure 3 and Figure 6 As shown, the present embodiment further provides a possible structure of the bolt 40, the bolt 40 includes a wide-diameter stud 400 and a narrow-diameter stud 401 connected to each other; the diameter of the wide-diameter stud 400 is larger than the diameter of the narrow-diameter stud 401, and a step 402 for cooperating with a nut to clamp the first flange 1 is formed between the wide-diameter stud 400 and the narrow-diameter stud 401; the wide-diameter stud 400 is screwed into the screw hole 20, the narrow-diameter stud 401 passes through the cover body through hole 10, and a pressure top block 41 is connected to the narrow-diameter stud 401. After adopting this setting, the step 402 can be screwed into the screw hole 20 along with the wide-diameter stud 400, and the formed step 402 will not affect the size of the first gap 5, and the step 402 can also cooperate with the pressure top block 41 to clamp the first flange 1.

[0054] Wherein, both ends of the bolt 40 are processed with threads, and the end of the bolt 40 is provided with a hexagon socket groove.

[0055] Furthermore, in order to reduce the wear of the sealing structure, Figure 2 As shown, during the first installation, the step 402 surfaces of the multiple steps 402 are maintained on the same horizontal plane. When the first flange 1 is assembled, the first flange 1 can clamp the compressed elastic sealing ring 3 with the second flange 2 in a horizontal manner, reducing the wear of the first flange 1, the second flange 2 and the elastic sealing ring 3, and ensuring the service life of the first flange 1, the second flange 2 and the elastic sealing ring 3. Before adjusting the gap, the first flange 1 is fixed by clamping the step 402 and the nut, and the multiple step surfaces are maintained on the same horizontal plane to ensure that the first flange 1 is horizontal. Then, the bolt 40 is tightened to move the first flange 1 and fix the nut, thereby completing the compression and readjustment of the elastic sealing ring 3.

[0056] Furthermore, in order to make the bolts 40 better fit and connect on the first flange 1 and the second flange 2, as shown in FIG. Figure 3 As shown, the length of the wide-diameter stud 400 is less than the depth of the screw hole 20, and the length of the narrow-diameter stud 401 is greater than the depth of the cover body through hole 10. The length setting of the wide-diameter stud 400 avoids wear caused by excessive screw connection, and the length setting of the narrow-diameter stud 401 provides it with a sufficient adjustable range, so that the bolt 40 can better cooperate with the first flange 1 and the second flange 2.

[0057] As a possible example, Figures 3 to 5 As shown, this embodiment further provides a possible matching structure of the first flange 1 and the second flange 2, the second flange 2 is provided with an annular groove 21, an elastic sealing ring 3 is provided in the annular groove 21, the first flange 1 is provided with an annular protrusion 11, the annular protrusion 11 is precisely matched with the annular groove 21, the annular protrusion 11 is inserted into the annular groove 21, the annular protrusion 11 and the annular groove 21 clamp the elastic sealing ring 3, after adopting this structural setting, the annular protrusion 11 cooperates with the annular groove 21 to squeeze the elastic sealing ring 3, and the elastic contact between the annular protrusion 11 and the annular groove 21 and the elastic sealing ring 3 is the main structure for realizing the sealing function.

[0058] In a specific embodiment, Figure 2As shown, the first flange 1 and the second flange 2 are arranged relative to each other to form a first gap, and are coaxially arranged to ensure that the contact surfaces of the two flanges are horizontal. The first flange 1 is provided with a plurality of cover through holes 10, and the plurality of cover through holes 10 are circumferentially evenly arranged around the central axis of the first flange 1. The second flange 2 is provided with a plurality of screw holes 20, and the plurality of screw holes 20 are circumferentially evenly arranged around the central axis of the second flange 2. The plurality of screw holes 20 and the cover through holes 10 are connected to the threaded connector 4, and a second gap is formed between the bottom of the screw holes 20 and the bottom of the threaded connector 4.

[0059] Among them, the first flange 1 is preferably a cover flange, the second flange 2 is preferably a pipeline flange, and the screw hole 20 can be a through hole or a blind hole. Those skilled in the art can choose according to their actual needs.

[0060] Furthermore, in order to avoid excessive movement, e.g. Figures 3 to 5 As shown, the protrusion height of the annular protrusion 11 is smaller than the groove depth of the annular groove 21. After adopting this setting, the annular protrusion 11 has a certain limit in moving toward the annular groove 21, and the annular protrusion 11 cannot directly abut against the bottom of the annular groove 21, avoiding mechanical interference.

[0061] Furthermore, in order to ensure that the elastic sealing ring 3 has a sealing effect after re-adjustment and compression, as Figure 3 As shown, the distance of the first gap 5 is 0-5% of the height of the elastic sealing ring 3. After adopting this setting, the distance of the first gap 5 is the ratio of the extrusion amount of the elastic sealing ring 3 in the working state to the original size, that is, when the elastic sealing ring 3 has been working for N years, the first gap is adjusted again, and the increase in the compression rate of the elastic sealing ring 3 is between 0-5%, which can effectively ensure that the elastic sealing ring 3 has a sealing effect after the re-adjustment of the compression.

[0062] Preferably, the distance of the first gap 5 is 5% of the height of the elastic sealing ring 3, which can compensate for the aging and damaged parts while ensuring the elasticity of the elastic sealing ring 3 and avoiding the situation where the elastic sealing ring 3 loses its elasticity due to excessive extrusion.

[0063] A second aspect of an embodiment of the present invention provides an oil-immersed transformer, comprising: a winding, an oil tank, an insulating bushing and an end face flange sealing structure;

[0064] A winding is arranged in the oil tank, the oil tank is sealedly connected to an insulating sleeve, and an end face flange sealing structure is connected to the insulating sleeve.

[0065] After adopting this setting method, the end face flange sealing structure can ensure the sealing of the transformer and prevent the transformer oil from leaking from the oil tank, so that it can be used as a cooling and insulating medium. It can fill the bubbles in the transformer to prevent the infiltration of gas, play an effective cooling role for the operation of the transformer, extend the service life of the transformer, avoid causing environmental problems, and avoid electrical safety hazards such as insulation breakdown, short circuit, burning and even explosion.

[0066] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

[0067] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

Claims

1. An end face flange sealing structure, comprising a first flange, a second flange, an elastic sealing ring and a plurality of threaded connectors, characterized in that: The first flange and the second flange elastically clamp the elastic sealing ring, and a first gap is left between the first flange and the second flange; The threaded connector is disposed on the first flange from top to bottom, the threaded connector is clamped with the first flange, and the threaded connector is connected to the first flange in a self-rotating manner; The threaded connector is threadedly connected to the second flange, a second gap is left between the threaded end of the threaded connector and the bottom of the threaded hole of the second flange, and the second gap is not smaller than the first gap; The threaded connection of the threaded connector is used to adjust the size of the first gap so that the first flange and the second flange can clamp or loosen the elastic sealing ring.

2. The end face flange sealing structure according to claim 1, characterized in that: The threaded connector includes a bolt and a capping block; The first flange is provided with a cover through hole; One end of the bolt is screwed into the screw hole, and the other end of the bolt passes through the cover through hole and is connected to the top pressing block; The bolt has a step, the first flange is mounted on the step, and the top block and the step clamp the first flange.

3. The end face flange sealing structure according to claim 2, characterized in that: The step surfaces of the plurality of steps are maintained on the same horizontal plane.

4. The end face flange sealing structure according to claim 2, characterized in that: The top pressing block is a nut; The nut is threadedly connected to the bolt, and the relative movement caused by the rotation of the nut and the rotation of the bolt in the threaded hole is used to locate the position of the first flange.

5. The end face flange sealing structure according to claim 2, characterized in that: The bolt comprises a wide-diameter stud and a narrow-diameter stud connected to each other; The step is formed between the wide-diameter stud and the narrow-diameter stud; The wide-diameter stud is screwed into the screw-connecting hole, the narrow-diameter stud passes through the cover through hole, and the top pressing block is connected to the narrow-diameter stud.

6. The end face flange sealing structure according to claim 5, characterized in that: The length of the wide-diameter stud is smaller than the hole depth of the screw hole, and the length of the narrow-diameter stud is larger than the hole depth of the cover body through hole.

7. The end face flange sealing structure according to claim 1, characterized in that: The distance of the first gap is 0-5% of the height of the elastic sealing ring.

8. The end face flange sealing structure according to claim 1, characterized in that: The second flange is provided with an annular groove, and the elastic sealing ring is provided in the annular groove; The first flange is provided with an annular protrusion, the annular protrusion is inserted into the annular groove, and the annular protrusion and the annular groove clamp the elastic sealing ring.

9. The end face flange sealing structure according to claim 8, characterized in that: The protrusion height of the annular protrusion is smaller than the groove depth of the annular groove.

10. An oil-immersed transformer, characterized in that: The end face flange sealing structure according to any one of claims 1 to 9 is applied, comprising: a winding, an oil tank, an insulating sleeve and the end face flange sealing structure; The winding is arranged in the oil tank, the oil tank is sealedly connected to the insulating sleeve, and the end face flange sealing structure is connected to the insulating sleeve.

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