Oil tank and transformer

Abstract

The oil tank comprises a tank body, a cover plate and a sealing gasket, an opening is formed in the top of the tank body, the cover plate is arranged at the opening, the sealing gasket is arranged on the upper edge of the opening and abuts against the cover plate, the portion, close to the cover plate, of the tank body is provided with an upper end face, and the upper end face is provided with a limiting groove. The sealing gasket is accommodated in the limiting groove; according to the technical scheme provided by the embodiment of the invention, the limiting groove is formed in the upper end face of the box body, and the limiting groove not only can play a role in mounting and limiting the sealing gasket, but also can accommodate the sealing gasket, so that the sealing gasket is prevented from being aged due to irradiation of sunlight and contact with air, and the service life of the sealing gasket is prolonged. The sealing performance of the oil tank is further guaranteed, and the use stability is prolonged.

Description

Technical Field

[0001] The embodiments in this application relate to the field of electrical engineering technology, and in particular to an oil tank and a transformer. Background Technology

[0002] Oil-immersed transformers are electrical devices widely used in power systems.

[0003] To facilitate the installation, maintenance, and repair of the transformer, the oil tank consists of two parts: the tank body and the cover plate. The cover plate is located at the opening of the tank body. During normal use, the tank body and cover plate need to ensure good sealing to prevent external moisture, dust, and impurities from entering the oil tank, thereby protecting the insulating oil and electrical components inside the transformer and extending the transformer's service life.

[0004] In traditional oil-immersed transformer designs, a sealing gasket is installed at the junction of the cover plate and the tank. However, due to prolonged exposure to sunlight and air, the material may age, potentially causing the seal to fail. Utility Model Content

[0005] Several embodiments in this application propose an oil tank designed to further ensure its sealing performance and extend its operational stability.

[0006] One embodiment of this application provides an oil tank comprising:

[0007] The box has an opening at the top;

[0008] A cover plate is provided over the opening; and

[0009] A sealing gasket is provided at the upper edge of the opening and abuts against the cover plate;

[0010] The box body has an upper end face near the cover plate, and the upper end face has a limiting groove, in which the sealing gasket is accommodated.

[0011] In one embodiment, the upper end face facing the cover plate has two limiting protrusions, the two limiting protrusions are arranged around the opening, and the two limiting protrusions and the upper end face form the limiting groove.

[0012] In one embodiment, the limiting groove includes a first limiting groove and a second limiting groove, and the box body has an extension facing the cover plate;

[0013] The extension portion, one of the limiting protrusions, and the upper end face form the first limiting groove, and the two limiting protrusions and the upper end face form the second limiting groove.

[0014] In one embodiment, the sealing gasket includes a first sealing gasket and a second sealing gasket, the first sealing gasket and the second sealing gasket being respectively disposed in the first limiting groove and the second limiting groove.

[0015] In one embodiment, the circumference of the second sealing gasket is greater than the circumference of the first sealing gasket, and the second sealing gasket is disposed on the side of the first sealing gasket away from the extension.

[0016] In one embodiment, the oil tank further includes a stop structure, which is disposed between the upper end face and the cover plate and abuts against the tank body and the cover plate respectively.

[0017] In one embodiment, the upper end face surrounds and extends beyond the opening, and the stop structure includes a plurality of stop portions, which are disposed on the upper end face and are evenly spaced along the circumference of the opening.

[0018] In one embodiment, the tank further includes fasteners, including bolts and nuts. The tank body has a first through hole at one end near the cover plate, and the cover plate has a second through hole. The bolt passes through the first through hole and the second through hole, and the nut abuts against one of the tank body and the cover plate.

[0019] This application also proposes a transformer that includes the oil tank as described above.

[0020] In several embodiments provided in this application, a limiting groove is provided on the upper end face. The limiting groove can accommodate the sealing gasket, preventing it from being exposed to sunlight and contacting air. This prevents the sealing gasket on the inner side from aging and failing due to prolonged exposure to ultraviolet radiation, thus ensuring the sealing performance of the fuel tank for long-term use. Specifically, the limiting groove is located on the upper end face of the tank body. It can be obtained by cutting a groove on the upper end face or by setting a limiting structure to enclose it. This application does not impose any restrictions on this method. The limiting groove not only serves to limit the installation of the sealing gasket but also accommodates it, preventing it from being exposed to sunlight and contacting air, which would lead to aging. This further ensures the sealing performance of the fuel tank and extends its service stability. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments or prior art of this application, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0022] Figure 1A schematic diagram of the structure of an embodiment of the fuel tank provided in this application;

[0023] Figure 2 for Figure 1 A partially enlarged view of the structure at point A in the first embodiment;

[0024] Figure 3 for Figure 1 A partially enlarged view of the structure at point A in the second embodiment.

[0025] Explanation of icon numbers:

[0026] 100. Fuel tank; 1. Tank body; 11. Upper end face; 111. Limiting protrusion; 12. Side plate; 121. Extension; 13. Limiting groove; 131. First limiting groove; 132. Second limiting groove; 1a. Opening; 1b. Receiving cavity; 2. Cover plate; 3. Sealing gasket; 31. First sealing gasket; 32. Second sealing gasket; 4. Fastener; 41. Bolt; 42. Nut; 43. Washer; 5. Stop structure; 51. Stop part. Detailed Implementation

[0027] The technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings of several embodiments. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0028] It should be noted that if multiple embodiments of this application involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0029] Furthermore, if multiple embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text implies three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0030] To facilitate the installation, maintenance, and repair of the transformer, the oil tank 100 comprises two parts: a tank body 1 and a cover plate 2. The cover plate 2 is located at the opening 1a of the tank body 1. During normal operation, the tank body 1 and the cover plate 2 need to ensure good sealing to prevent external moisture, dust, and impurities from entering the oil tank 100, thereby protecting the insulating oil and electrical components inside the transformer and extending its service life. In traditional oil-immersed transformer designs, a sealing gasket 3 is installed at the junction of the cover plate 2 and the tank body 1. However, due to prolonged exposure to ultraviolet (UV) radiation, which contains high-energy photons, the sealing gasket 3 can penetrate the surface of the gasket material and damage the internal chemical bond structure. For example, for rubber gaskets 3, UV radiation can cause the rubber molecular chains to break, cross-link, or oxidize, leading to reduced elasticity, hardening, brittleness, and even cracking. This degradation of material properties will damage the integrity and elastic sealing function of the sealing gasket 3, preventing it from tightly adhering to the sealing surface, resulting in sealing failure and leakage. Furthermore, contact with air can also cause oxidation of the sealing gasket 3.

[0031] To address the aforementioned problems, this application proposes an oil tank 100 that can provide isolation and protection for the sealing gasket 3, thereby solving the above-mentioned technical issues.

[0032] Please refer to further information. Figures 1 to 3 In one embodiment of this application, the oil tank 100 includes a tank body 1, a cover plate 2, and a sealing gasket 3. The top of the tank body 1 is provided with an opening 1a, the cover plate 2 is provided in the opening 1a, and the sealing gasket 3 is provided on the upper edge of the opening 1a and abuts against the cover plate 2. The tank body 1 is provided with an upper end surface 11 near the cover plate 2, and the upper end surface 11 is provided with a limiting groove 13, in which the sealing gasket 3 is accommodated.

[0033] In the technical solution of this application, the oil tank 100 adopts a split structure design, including a tank body 1 and a cover plate 2 covering the opening 1a of the tank body 1. The oil tank 100 is divided into two parts: the tank body 1 and the cover plate 2. This design facilitates the assembly and maintenance of the transformer. The cover plate 2 can be easily disassembled, allowing for inspection, cleaning, or replacement of components inside the oil tank 100, improving maintenance efficiency and reducing maintenance costs. The split structure also facilitates heat dissipation. The connection between the cover plate 2 and the tank body 1 can be designed more flexibly, thereby optimizing the heat dissipation path, enhancing the heat dissipation effect of the transformer, and ensuring that the equipment maintains good performance during long-term operation.

[0034] In several embodiments provided in this application, a limiting groove 13 is provided on the upper end face 11. The limiting groove 13 can accommodate the sealing gasket 3, preventing it from being exposed to sunlight and contacting air. This prevents the sealing gasket 3 located on the inner side from aging and failing due to prolonged exposure to ultraviolet radiation, thus ensuring the sealing performance of the fuel tank 100 for long-term use. Specifically, the limiting groove 13 is provided on the upper end face 11 of the tank body 1. It can be obtained by slotting the upper end face 11 or by providing a limiting structure to enclose it. This application does not limit this. The limiting groove 13 not only serves to limit the installation of the sealing gasket 3, but also accommodates the sealing gasket 3, preventing it from being exposed to sunlight and contacting air, thus preventing aging and further ensuring the sealing performance of the fuel tank 100 and extending its service stability.

[0035] In the above embodiment, the oil tank 100 is provided with only one sealing gasket 3, which is protected by the limiting groove 13. In order to achieve a better sealing effect and protection effect on the sealing gasket 3, two or more sealing gaskets 3 can also be provided. The sealing gasket 3 located away from the extension 121 can be considered as an auxiliary sealing gasket 3. The auxiliary sealing gasket 3 can block some of the sunlight that enters through the gap between the cover plate 2 and the tank 1, and can also isolate the air, preventing sunlight and air from entering the inside, thereby forming an effective protection for the sealing gasket 3 close to the extension 121.

[0036] It should be noted that two sealing gaskets 3 can be provided between the housing 1 and the cover plate 2, that is, one sealing gasket 3 is fitted around the outer periphery of another sealing gasket 3, and the two are spaced apart; or more than two sealing gaskets 3 can be provided, that is, multiple sealing gaskets 3 are sequentially fitted around the outer periphery of adjacent inner sealing gaskets 3, and each pair of adjacent sealing gaskets 3 are spaced apart. This application does not limit the number of sealing gaskets 3. In one embodiment of this application, the number of sealing gaskets 3 is two. The sealing gasket 3 located on the inner side, that is, near the opening 1a of the housing 1, is the first sealing gasket 31, and the sealing gasket 3 located on the outer side, that is, away from the opening 1a of the housing 1, is the second sealing gasket 32. The second sealing gasket 32 ​​is fitted around the outer periphery of the first sealing gasket 31, and the two are spaced apart. For details, please refer to further reading. Figure 1 and Figure 2Two sealing gaskets 3 are installed. The outer second sealing gasket 32 ​​can effectively block ultraviolet rays, preventing the inner first sealing gasket 31 from aging due to prolonged ultraviolet radiation, thus avoiding sealing failure caused by the performance degradation of the sealing gasket 3. As described above, the double sealing structure also provides additional safety protection. Even if one sealing gasket 3 experiences a minor leak or damage, the other sealing gasket 3 can still maintain a good sealing effect, further enhancing the sealing reliability of the oil tank 100. This effectively prevents external moisture, dust, and impurities from entering the interior of the oil tank 100, thereby better protecting the insulating oil and electrical components inside the transformer, extending the service life of the transformer, and ensuring the safe and stable operation of the power system.

[0037] Understandably, the sealing gasket 3 is fixed to the upper end face 11 of the housing 1 by pressing it against the cover plate 2. The cover plate 2 compresses the sealing gasket 3, causing it to deform, thus generating friction between the sealing gasket 3 and the upper end face 11 and the cover plate 2, achieving fixation. However, during transformer operation, vibrations may occur due to electromagnetic forces, mechanical structure influences, cooling system effects, external environmental factors, load changes, installation foundation, and material aging. High-frequency vibrations can cause the sealing gasket 3 to shift relative to the housing 1, leading to misalignment and sealing failure. To prevent the sealing gasket 3 from shifting or becoming misaligned due to vibration, the upper end face 11 of the housing 1 is provided with a limiting structure. This limiting structure fixes the sealing gasket 3, preventing misalignment. For further details, please refer to [link to relevant documentation]. Figure 2 In this embodiment, the oil tank 100 is provided with two sealing gaskets 3. In order to fix the sealing gaskets 3 with different inner diameters respectively, the upper end face 11 is provided with two limiting structures. The two limiting structures are spaced apart along the outer diameter direction of the upper end face 11. The first sealing gasket 31 and the second sealing gasket 32 ​​are respectively fitted on the inner limiting structure and the outer limiting structure.

[0038] It should be noted that the limiting structure can be a ring-shaped structure as a whole, or a discontinuous strip-shaped structure around the opening 1a, that is, a structure evenly spaced along the shape path of the outer wall of the box 1. Alternatively, multiple positioning posts can be spaced around the opening 1a of the box 1. This application does not limit the specific shape of the limiting structure. In one embodiment of this application, the limiting structure is a limiting protrusion 111. For details, please refer to further reference. Figure 2In this embodiment, the limiting protrusion 111 is a continuous structure, and the first sealing gasket 31 located on the inner ring is sleeved on the extension 121 of the side plate 12. When manufacturing the box 1, the upper end face 11 and the side plate 12 are manufactured by processing and then welding them separately. First, multiple side plates 12 are connected end to end to form a box-shaped structure with an upper opening 1a. Then, the upper end face 11 is welded to the side of the side plate 12 facing away from the receiving cavity 1b. By sinking the upper end face 11 a certain distance, it is misaligned with the opening 1a of the box 1, so that part of the side plate 12 of the box 1 is located above the upper surface of the upper end face 11, which is the aforementioned extension 121 structure. Since the extension 121 and the side plate 12 of the box 1 are an integral structure, the structural strength is high, and it is close to the opening 1a. When the first sealing gasket 31 is sleeved on the extension 121, it can ensure that it is sealed near the opening 1a, thereby achieving a better sealing effect.

[0039] In several embodiments provided in this application, two or more sealing gaskets 3 are provided between the tank body 1 and the cover plate 2, spaced apart. The outer sealing gasket 3 can block the entry of ultraviolet rays, thereby preventing the inner sealing gasket 3 from aging and failing due to prolonged exposure to ultraviolet rays, thus ensuring the sealing performance of the oil tank 100 for long-term use. Specifically, taking two sealing gaskets 3 as an example, one sealing gasket 3 is located around the other sealing gasket 3. The outer sealing gasket 3 can be considered as the auxiliary sealing gasket 3, and the sealing gasket 3 located near the inner side of the opening 1a is considered as the main sealing gasket 3. Both sealing gaskets 3 are fixed by limiting structures located on the upper edge of the opening 1a. Since transformers are generally installed in outdoor open-air environments, the auxiliary sealing gasket 3, located on the outside, can block ultraviolet rays from the outside, preventing the main sealing gasket 3 from aging due to prolonged exposure to ultraviolet rays and affecting the subsequent sealing effect. Moreover, providing two sealing gaskets 3 can significantly enhance the overall sealing performance of the oil tank 100. The double sealing design can effectively prevent leakage problems caused by the failure of a single sealing gasket 3.

[0040] In one embodiment of this application, the second sealing gasket 32 ​​is sleeved on the limiting protrusion 111, which is located on the upper surface of the upper end face 11. It should be noted that the limiting protrusion 111 can be connected to the upper surface of the upper end face 11 by welding, or it can be integrally formed with the upper end face 11. This application does not impose any limitations on this. In one embodiment of this application, the limiting protrusion 111 is welded to the upper surface of the upper end face 11. Welding ensures a firm connection between the limiting protrusion 111 and the upper end face 11, maintaining stability even during transformer operation when vibration or external impact occurs, effectively preventing the sealing gasket 3 from shifting or loosening due to vibration. Furthermore, the welding process is relatively simple, enabling rapid fixation and connection of the limiting protrusion 111, thus improving production efficiency. Furthermore, the welded limiting protrusion 111 also serves to limit the position of the cover plate 2. When the cover plate 2 is closed on the housing 1, the sealing gasket 3 first contacts the cover plate 2 and is compressed to deform until the cover plate 2 abuts against the limiting protrusion 111, thereby limiting the position of the cover plate 2. In this embodiment, the extension 121 is about 5mm higher than the upper surface of the upper end face 11, thereby ensuring that there is a sufficient gap between the cover plate 2 and the housing 1 to allow the sealing gasket 3 to deform and thus achieve a seal.

[0041] Furthermore, in another embodiment of this application, a limiting protrusion 111 is also provided on the outer side of the second sealing gasket 32, that is, on the side of the second sealing gasket 32 ​​facing away from the first sealing gasket 31. The two limiting protrusions 111 together form an annular groove with the opening 1a facing upward. The second sealing gasket 32 ​​is accommodated in this annular groove. By adding a limiting protrusion 111 on the outer side of the second sealing gasket 32, the limiting protrusion 111 on the outer side can block ultraviolet rays, preventing the second sealing gasket 32 ​​from being completely exposed to ultraviolet rays, thereby protecting the second sealing gasket 32 ​​and preventing its aging rate from accelerating. In addition, by providing two spaced-apart limiting protrusions 111, displacement of the second sealing gasket 32 ​​can be further prevented. It not only restricts movement towards the opening 1a side but also restricts movement away from the opening 1a side, thereby playing a more reliable limiting role. Furthermore, the upper surfaces of the limiting protrusions 111 located on both sides of the second sealing gasket 32 ​​are flush, forming a contact surface for contacting the lower end face of the cover plate 2. The two limiting protrusions 111 increase the area of ​​the contact surface, thereby increasing the stress points between the cover plate 2 and the housing 1 and improving the overall structural reliability. The two limiting protrusions and the extension 121 of the side plate 12 of the housing 1 together form a support structure for the cover plate 2, preventing further compression of the gap between the cover plate 2 and the housing 1.

[0042] In another embodiment of this application, a stop structure 5 is further provided between the cover plate 2 and the box body 1. The stop structure 5 is located on the upper surface of the upper end face 11. For details, please refer to further reference. Figure 2The stop structure 5 is a strip of round steel. This strip of round steel serves as a stop structure 5 between the transformer cover plate 2 and the housing 1. It effectively prevents the cover plate 2 from shifting or loosening due to vibration or external forces during operation. By increasing physical obstruction, it ensures the sealing and stability between the cover plate 2 and the housing 1, thereby improving the transformer's operational safety and reliability. Simultaneously, the round steel strip has a simple structure and high strength, capable of withstanding certain pressure and impact, further enhancing the robustness of the connection between the cover plate 2 and the housing 1, and extending the equipment's service life. Furthermore, the stop structure 5 and the limiting protrusion together provide support for the cover plate 2, preventing direct contact between the cover plate 2 and the housing 1.

[0043] Furthermore, the bar round steel can be a continuous structure or a segmented structure, consisting of multiple bar round steel segments, i.e., stop portions 51. The multiple bar round steel segments are arranged circumferentially around the opening 1a of the tank body 1. In one embodiment of this application, the stop structure 5 includes multiple annular arrays of bar round steel segments, with the bar round steel segments maintaining a uniform spacing. Setting the stop structure 5 as a discontinuous structure can further save the required materials and reduce the self-weight of the transformer tank 100, thereby achieving the lightweighting of the tank 100.

[0044] In the second embodiment proposed in this application, the limiting structure is a limiting groove 13. In this embodiment, taking an oil tank 100 with two sealing gaskets 3 as an example, the first sealing gasket 31 and the second sealing gasket 32 ​​are respectively accommodated in the first limiting groove 131 and the second limiting groove 132. The first limiting groove 131 and the second limiting groove 132 are machined downwards from the upper surface of the upper end face 11. In this embodiment, the first limiting groove 131 and the second limiting groove 132 respectively limit the position of the first sealing gasket 31 and the second sealing gasket 32. There is no need to set a raised limiting protrusion 111 and a stop structure 5. The limiting groove 13 structure can precisely fix the position of the sealing gasket 3, preventing it from shifting or deforming during installation or operation, thereby ensuring the reliability of the seal. By slotting the upper end face 11, the overall structure of the oil tank 100 is simplified, reducing manufacturing costs and complexity. At the same time, the design of the limiting groove 13 helps reduce stress concentration problems that may be caused by the raised structure, enhancing the overall strength and durability of the oil tank 100. In addition, the limiting groove 13 structure can better adapt to sealing gaskets 3 of different sizes, improving the flexibility and versatility of the design.

[0045] It should be noted that this application does not limit the material of the sealing gasket 3; either nitrile rubber or fluororubber can be used. Nitrile rubber has excellent oil resistance and abrasion resistance, and can maintain good sealing performance in oil-immersed environments for a long time. Nitrile rubber also has high mechanical strength and aging resistance, and can maintain stable performance over a wide temperature range, ensuring the sealing performance of the transformer tank 100. Fluororubber has excellent high-temperature resistance and chemical stability, and can maintain sealing performance in extreme temperature and corrosive environments. It has good resistance to transformer oil and other chemical media, effectively preventing oil leakage and the ingress of external impurities, thus extending the service life of the transformer. The specific material selection can be adapted to the actual needs of the product and the installation environment.

[0046] The oil tank 100 provided in this application can be either a square or cylindrical structure. In one embodiment of this application, the tank 1 is a square structure. The square structure has high space utilization, making more efficient use of limited installation space, and is suitable for use in substations or industrial sites with limited installation space. Secondly, the manufacturing process of the square oil tank 100 is relatively simple, facilitating processing and assembly. The square structure of the oil tank 100 exhibits excellent heat dissipation; its larger surface area facilitates natural convection of the transformer oil, thereby more effectively dissipating heat and ensuring the stability and reliability of the transformer during long-term operation. Simultaneously, the square oil tank 100 has good structural strength, better able to withstand the mechanical stress and internal pressure generated during transformer operation, improving equipment safety.

[0047] In one embodiment of this application, the housing 1 and the cover plate 2 are connected by fasteners 4, which include bolts and nuts 42. For details, please refer to further reading. Figure 2 Correspondingly, the end of the housing 1 near the cover plate 2 has a first through hole, and the cover plate 2 has a second through hole. Each first through hole on the housing 1 and each second through hole on the cover plate 2 are coaxially arranged. Bolts pass through the first and second through holes in sequence. One end of the bolt has a bolt head, which abuts against the side of the cover plate 2 facing away from the housing 1. Nut 42 abuts against the side of the housing 1 facing away from the cover plate 2. The bolted connection ensures a firm and reliable connection between the two, effectively preventing loosening and leakage caused by vibration or external force, thereby ensuring the sealing and stability of the transformer tank 100 and extending the service life of the equipment. A washer 43 is provided between the nut 42 and the housing 1 to prevent the bolt from causing excessive local compression of the connecting parts, protecting the surface of the connecting parts and avoiding damage.

[0048] This application also proposes a transformer, which is an oil-immersed transformer, including the oil tank 100 as described above. The specific structure of the oil tank 100 is as described in the above embodiments. Since this transformer adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0049] The above description is merely an exemplary embodiment of this application and does not limit the patent scope of this application. Any equivalent structural transformations made based on the technical concept of this application and the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A fuel tank, characterized in that, include: The box (1) has an opening (1a) at the top; Cover plate (2) is provided over the opening (1a); as well as A sealing gasket (3) is provided at the upper edge of the opening (1a) and abuts against the cover plate (2); The box body (1) has an upper end face (11) near the cover plate (2), the upper end face (11) has a limiting groove, and the sealing gasket (3) is accommodated in the limiting groove (13). The upper end face (11) facing the cover plate (2) is provided with two limiting protrusions (111). The two limiting protrusions (111) are arranged around the opening (1a), and the two limiting protrusions (111) and the upper end face (11) form the limiting groove (13).

2. The fuel tank as described in claim 1, characterized in that, The limiting groove (13) includes a first limiting groove (131) and a second limiting groove (132), and the box body (1) is provided with an extension (121) facing the cover plate (2); The extension (121), one of the limiting protrusions (111) and the upper end face (11) form the first limiting groove (131), and the two limiting protrusions (111) and the upper end face (11) form the second limiting groove (132).

3. The fuel tank as described in claim 2, characterized in that, The sealing gasket (3) includes a first sealing gasket (31) and a second sealing gasket (32), and the first sealing gasket (31) and the second sealing gasket (32) are respectively disposed in the first limiting groove (131) and the second limiting groove (132).

4. The fuel tank as described in claim 3, characterized in that, The circumference of the second sealing gasket (32) is greater than the circumference of the first sealing gasket (31), and the second sealing gasket (32) is disposed on the side of the first sealing gasket (31) away from the extension (121).

5. The fuel tank as described in claim 1, characterized in that, The limiting protrusion (111) and the box body (1) are integrally formed.

6. The fuel tank as described in any one of claims 1 to 5, characterized in that, The oil tank also includes a stop structure (5), which is located between the upper end face (11) and the cover plate (2) and abuts against the tank body (1) and the cover plate (2) respectively.

7. The fuel tank as described in claim 6, characterized in that, The upper end face (11) surrounds and extends out of the opening (1a), and the stop structure (5) includes a plurality of stop parts (51), which are disposed on the upper end face (11) and are evenly spaced along the circumference of the opening (1a).

8. The fuel tank as described in any one of claims 1 to 5, characterized in that, The oil tank also includes fasteners (4), which include bolts (41) and nuts (42). The tank body (1) has a first through hole at one end near the cover plate (2), and the cover plate (2) has a second through hole. The bolts (41) pass through the first through hole and the second through hole, and the nuts (42) abut against one of the tank body (1) and the cover plate (2).

9. A transformer, characterized in that, The fuel tank includes any one of claims 1 to 8.

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