Power transformer with self-cleaning function

Abstract

The invention relates to a power transformer technology with a self-cleaning function. A transformer main body, an oil circulating system and a filtering system are included; wherein the filtering system comprises a mounting shell, a filtering component capable of sliding up and down is arranged in the mounting shell, a filtering net II is assembled at the upper end of the filtering component, and a compression spring is arranged at the lower end of the filtering component; a V-shaped by-pass pipe is arranged on one side of the installation shell, the upper end of the by-pass pipe is communicated with the through hole of the installation shell, and the lower end of the by-pass pipe is communicated with a liquid inlet III in the bottom of the installation shell. When the pressure difference is gradually increased due to impurity accumulation at the upper end of the filter screen II, the filter component can overcome friction force to smoothly slide downwards, oil flows into the bypass pipe through the through hole, vortexes are formed at the bent part of the V-shaped structure to precipitate impurities, and meanwhile, the oil on the lower side of the filter screen II reversely impacts to realize backwashing; once the impurities are effectively cleaned, the compression spring can play a role to push the filtering assembly to reset quickly.

Description

Technical Field

[0001] This invention relates to an oil filtration device for power transformers, and more particularly to a power transformer with a self-cleaning function. Background Technology

[0002] As a key piece of equipment in the power system, the reliability of power transformers has a decisive impact on the stability of the power grid. Transformer oil, as an important insulating and cooling medium, must be forcibly circulated through an oil circulation mechanism during transformer operation to effectively conduct the heat generated by the core and windings and maintain its insulation performance.

[0003] However, during the oil circulation process, impurities such as metal particles, fibers, and dust inevitably get mixed in. If these impurities accumulate over a long period, they will not only reduce the oil's heat dissipation efficiency but may also lead to a decline in insulation performance, and may even induce partial discharge or short-circuit faults. Therefore, the filtration mechanism plays a crucial role in the transformer oil circulation system. Its main function is to remove impurities from the oil, ensuring its cleanliness and thus guaranteeing the stable operation of the transformer.

[0004] In existing technologies, filtration mechanisms typically employ a fixed-installation filter screen structure, with a rigid connection between the filter screen and the oil circulation pipeline. When oil flows through the filter screen, impurities are trapped on its upper surface. However, due to the continuous impact of the oil, impurities accumulate on the filter screen surface. As the accumulation increases, the flow area of ​​the filter screen gradually decreases, leading to increased resistance to oil flow and consequently higher pressure within the oil circulation pipeline. This phenomenon increases the workload of the oil pump, reducing circulation efficiency; furthermore, excessive pressure may cause leaks or even ruptures at pipeline joints. To address these issues, existing technologies require professional personnel to periodically shut down the system to disassemble, clean, or replace the filter screen. This not only increases maintenance costs and labor intensity but may also disrupt the continuity of power supply due to downtime. Furthermore, improper manual cleaning procedures may introduce new contaminants, further affecting oil quality.

[0005] Given the shortcomings of existing filtration mechanisms, such as low cleaning efficiency, high maintenance costs, and impact on continuous equipment operation, there is an urgent need to develop a filtration solution that can achieve automatic cleaning. Summary of the Invention

[0006] To address the limitations of existing technologies, this invention proposes a power transformer with a self-cleaning function. This design, through a built-in mechanism, can automatically remove impurities from the filter screen without external intervention, thereby reducing maintenance costs and preventing the filter screen from interfering with the normal operation of the transformer. This solution effectively solves the problem that filter screen cleaning in existing technologies relies entirely on manual operation, overcoming the drawbacks of time-consuming operation, high labor intensity, and the ease with which oversights can occur.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A power transformer with self-cleaning function includes a transformer body equipped with an oil circulation mechanism and a filtration mechanism. The oil circulation mechanism's inlet port I and the filtration mechanism's outlet port II are connected to the inner cavity of the transformer body. The oil circulation mechanism's outlet port I is connected to the filtration mechanism's inlet port II. The filtration mechanism includes a mounting housing with vertically axially extending sections. The inlet port II is located at the upper end of the mounting housing, and the outlet port II is located at the side end of the mounting housing. A bypass pipe is provided on one side of the mounting housing, with its upper opening connected to a through hole at the side end of the mounting housing. The lower end of the bypass pipe is connected to the liquid inlet III at the bottom of the mounting housing. A filter screen I is installed inside the section of the bypass pipe near the liquid inlet III. A filter component is slidably connected inside the mounting housing. The filter component moves vertically relative to the mounting housing. The filter component includes a filter screen II. Initially, the height of the upper surface of the filter component is not less than the height of the upper surface of the through hole. As the filter component moves downward, the height of the upper surface of the filter component becomes less than the height of the upper surface of the through hole. A compression spring is coaxially installed at the lower end of the filter component. The other axial end of the compression spring abuts against the mounting housing.

[0008] Preferably, control valves are provided inside the through hole and the outlet II, wherein control valve I is provided inside the through hole and control valve II is provided inside the outlet II, and the opening and closing states of control valve I and control valve II are completely opposite. Control valve II is kept in the normally open state, and control valve I opens when the filter component moves downward.

[0009] Preferably, the control valve includes a positioning ring fixedly connected to the mounting housing, a drive ring rotatably connected to one side of the positioning ring, and a drive ring drivingly connected to the filter component. Multiple positioning slots are equidistantly arranged around the central axis of the drive ring, with the center line of each positioning slot coinciding with the radius line of the drive ring. Multiple drive slots are circumferentially arranged on each drive ring, corresponding one-to-one with the positioning slots. The distances between the two ends of each drive slot and the central axis of the drive ring are unequal, and the inner wall of each drive slot is smoothly transitioned. A follower rod is inserted into the interior of each positioning slot and its corresponding drive slot. A baffle plate is sleeved on the outer side of each follower rod, and the baffle plate is slidably connected to the positioning ring. When multiple baffle plates abut against each other, the projection of the multiple baffle plates on the vertical plane completely covers the projection of the positioning ring and the central aperture of the drive ring on the vertical plane.

[0010] Preferably, each drive ring is provided with two tension springs on its side end. One end of the tension spring is movably connected to the drive ring. At the same time, of the two tension springs corresponding to each drive ring, the tension spring whose other end is movably connected to the mounting housing is tension spring I, and the tension spring whose other end is movably connected to the filter component is tension spring II. When the control valve I is in the closed state, tension springs I and II corresponding to the control valve I are both in the stretched state, and the control valve I has a tendency to close under the action of tension spring I.

[0011] Preferably, when the control valve II is in the open state, the tension spring I corresponding to the control valve II is in the stretched state, and the control valve I has a tendency to close under the action of the tension spring I. At the same time, the tension spring II corresponding to the control valve I abuts against the filter component.

[0012] Preferably, a one-way valve is provided inside the liquid inlet III. The one-way valve includes a sealing plate disposed on the upper side of the liquid inlet III. The sealing plate is rotatably connected to the lower inner wall of the mounting housing via a pivot.

[0013] Preferably, the filter component includes an outer shell, inside which a plurality of horizontally oriented contact plates are rotatably connected. The plurality of contact plates are equidistantly arranged around the central axis of the outer shell, and the maximum distance between the side end of each contact plate and its central axis is greater than the distance between its central axis and the lower end face of the filter screen II. Each side end of the contact plate is provided with a return spring, the two axial ends of the return spring being movably connected to the corresponding contact plate and the inner wall of the outer shell, respectively. When the return spring is not affected by external force, the contact plate does not contact the filter screen II.

[0014] Preferably, when the reset spring is not affected by external force, the angle between the upper surface of the contact plate and the horizontal plane is greater than 0° and less than 90°.

[0015] Preferably, the upper end face of the filter element is at the same horizontal plane as the upper end face of the through hole, and the lower end face of the filter element is at the same horizontal plane as the upper end face of the liquid outlet II.

[0016] Preferably, the bypass pipe includes a sedimentation pipe, the upper end of which is connected to a through hole, and a return pipe is connected to the side end of the sedimentation pipe. The upper end of the return pipe is connected to the liquid inlet III. Meanwhile, the lower end of the sedimentation pipe has an open structure and a cap is detachably and sealingly connected to the lower end of the sedimentation pipe.

[0017] Compared with the prior art, the beneficial effects of the present invention are: Automatic cleaning mechanism, no manual intervention required: When impurities accumulate on the upper part of filter screen II, reducing flowability, the oil pressure difference between the upper and lower sides of filter screen II will increase. When the downward oil pressure on filter screen II exceeds the frictional resistance between the filter component and the mounting housing, as well as the supporting force provided by the compression spring, the filter component will automatically slide downward, connecting the oil on the upper side of filter screen II with the inner cavity of the bypass pipe. At this time, the oil pressure difference between the upper side of filter screen II and the oil pressure inside the bypass pipe drives the upper side oil to carry the impurities accumulated on the surface of filter screen II into the interior of the bypass pipe; the V-shaped structure of the bypass pipe allows the oil to form a vortex at the bend, using centrifugal force to settle the impurities at the bottom, achieving automatic impurity separation without the need for manual disassembly and cleaning.

[0018] The backwashing mechanism enhances the cleaning effect: During the downward movement of the filter components, filter screen II is pressed down and moves downward. Due to its incompressibility, the oil on the lower side of filter screen II impacts filter screen II upward, forming a backwash, thereby removing the adhering substances on the surface of filter screen II and improving the efficiency of impurity removal. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the internal structure of the mounting housing of the present invention; Figure 3 This is a schematic diagram showing the positional relationship between the filter component and the compression spring of the present invention; Figure 4 This is a schematic diagram showing the connection relationship between the mounting housing and the bypass pipe of the present invention; Figure 5 This is a schematic diagram showing the relationship between the filter component and control valve II of the present invention; Figure 6 This is a schematic diagram showing the relationship between the filter component and control valve I of the present invention; Figure 7 This is a schematic diagram showing the mating relationship between the positioning ring and the driving ring of the present invention; Figure 8 This is a schematic diagram of the internal structure of the outer shell of the present invention; Figure 9 This is a schematic diagram showing the relationship between the contact plate and the reset spring in this invention.

[0020] In the diagram: 1. Transformer body; 2. Oil circulation mechanism; 3. Filtering mechanism; 31. Mounting housing; 311. Outlet II; 312. Inlet II; 313. Through hole; 314. Inlet III; 32. Filtering component; 321. Filter screen II; 322. Outer housing; 323. Contact plate; 324. Return spring; 33. Control valve; 331. Control valve I; 332. Control valve II; 3301. Pull... Spring; 33011, Tension Spring I; 33012, Tension Spring II; 3302, Positioning Ring; 3303, Positioning Groove; 3304, Drive Ring; 3305, Drive Groove; 3306, Follower Rod; 3307, Baffle Plate; 34, Compression Spring; 35, Filter Screen I; 36, Cover; 37, Bypass Pipe; 371, Sedimentation Pipe; 372, Return Pipe; 38, One-Way Valve; 381, Sealing Plate; 382, ​​Pivot. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0023] A power transformer with self-cleaning function has the following main function: when filtering the oil inside the transformer, it prevents excessive impurities from adhering to and accumulating on the filter screen, so as to avoid reducing the filter screen's throughput and thus preventing damage to the oil circulation pipeline due to excessive pressure.

[0024] like Figure 1 As shown, this device is the same as the existing technology device, including a transformer body 1 and an oil circulation mechanism 2 disposed on the upper side of the transformer body 1.

[0025] It should be noted that, in addition to the pipes used to realize the flow of oil, the oil circulation mechanism 2 also includes a corresponding oil pump (not shown in the figure; only the housing of the oil circulation mechanism 2 is shown in the figure; the oil pump is usually located inside the housing or on one side of the housing), and the circulation of oil is realized through the liquid delivery function of the oil pump.

[0026] Correspondingly, a filter mechanism 3 is provided between the outlet I of the oil circulation mechanism 2 and the transformer body 1, through which impurities inside the oil are filtered.

[0027] Specifically, in order to achieve the circulation of oil and ensure the cooling effect of oil on the transformer body 1, this device stipulates that the inlet I of the oil circulation mechanism 2 and the outlet II 311 of the filter mechanism 3 are connected to the inner cavity of the transformer body 1, and the outlet I of the oil circulation mechanism 2 is connected to the inlet II 312 of the filter mechanism 3.

[0028] Accordingly, in order to reduce the workload of the oil pump in the oil circulation mechanism 2, this device constrains the inlet II 312 of the filter mechanism 3 to be located above it, while the outlet II 311 of the filter mechanism 3 is located below it. This measure can make full use of gravitational potential energy to help realize the circulation of oil.

[0029] It is important to note that in existing technical devices, the filtration mechanism 3 typically achieves its filtration function using a filter screen. When a significant amount of deposits and build-up accumulates on the upper surface of the filter screen (impurities in the oil are affected by the impact of the oil, and thus bear the downward pressure of the oil, causing the impurities to be squeezed onto the upper surface of the filter screen, forming deposits), the filter screen's flow performance will decrease. In this case, existing technical devices generally require professional technicians to disassemble, clean, and replace the filter screen.

[0030] Please refer to Figure 2 , Figure 3 , Figure 4 Unlike existing devices, the filter mechanism 3 in this device includes a mounting housing 31, which is axially arranged vertically. That is, the upper opening (inlet II 312) of the mounting housing 31 is connected to the outlet I of the oil circulation mechanism 2, while the lower opening (outlet II 311) of the mounting housing 31 is connected to the inner cavity of the transformer body 1.

[0031] It should be noted that the lower opening of the mounting housing 31 is located on the side end face of the mounting housing 31, and the central axis of this opening (liquid outlet II 311) is horizontal.

[0032] Specifically, in order to filter the oil, the device has a filter component 32 inside the mounting housing 31, and a filter screen II 321 is provided on the upper side of the filter component 32.

[0033] It is important to emphasize that filter screen II 321 has the same structure as the filter screens in existing technology devices, and its main function is to filter the oil. In actual operation, the oil sprayed from outlet I of the oil circulation mechanism 2 enters the housing 31 through inlet II 312, and then passes through filter screen II 321 and returns to the inner cavity of the transformer body 1 from outlet II 311. Therefore, in reality, impurities in the oil will remain on the upper part of filter screen II 321.

[0034] Meanwhile, during actual operation, when a lot of impurities accumulate on the upper end of filter screen II 321 and a lot of impurities adhere to filter screen II 321, the flowability of filter screen II 321 will decrease, and a pressure difference will appear between the upper and lower ends of filter screen II 321. Filter screen II 321 will be subjected to downward pressure from the oil at its upper end.

[0035] Therefore, this device constrains the connection between the filter element 32 and the mounting housing 31 to a sliding connection. This causes the filter element 32 to move vertically relative to the mounting housing 31 when the downward pressure on the filter screen 321 exceeds the frictional resistance between the filter element 32 and the mounting housing 31.

[0036] Based on the above principle, this device has a bypass pipe 37 with a vertical projection of V-shape on one side of the mounting housing 31. The upper opening of the bypass pipe 37 is connected to the through hole 313 on the side of the mounting housing 31, and the lower opening of the bypass pipe 37 is connected to the liquid inlet III 314 at the bottom of the mounting housing 31.

[0037] Therefore, in actual operation, it is only necessary to ensure that the downward pressure on the filter element 32 is sufficient to drive it downwards to a position below the through hole 313 to effectively clean the deposits on the upper end of the filter screen II 321. That is, during actual operation, when the amount of impurities accumulated on the upper end of the filter screen II 321 exceeds the expected value (i.e., the downward pressure on the filter screen II 321 is greater than the frictional resistance between the filter element 32 and the mounting housing 31), after the filter element 32 moves downwards to a position below the through hole 313, the oil will carry the impurities accumulated on the upper end of the filter screen II 321 into the bypass pipe 37 through the through hole 313. At this time, utilizing the V-shaped structure of the bypass pipe 37 itself, the oil can form a vortex at the bend of the bypass pipe 37 (the turning point at the bottom of the V-shaped structure), causing the impurities to settle at the bend of the bypass pipe 37, thereby preventing excessive pressure difference between the upper and lower ends of the filter screen due to the accumulation of a large amount of impurities on the upper end of the filter screen II 321.

[0038] Please refer to Figure 3 , Figure 4Specifically, the bypass pipe 37 includes a sedimentation pipe 371, the upper end of which is connected to the through hole 313, and the side end of the sedimentation pipe 371 is connected to a return pipe 372, the upper end of which is connected to the inlet III 314. This design utilizes the inclined central axis of the return pipe 372, combined with its placement, to create a special structure where the return pipe 372 and the sedimentation pipe 371 form a V-shape when projected vertically.

[0039] Furthermore, the lower end of the sedimentation tube 371 has an open structure, and the lower end of the sedimentation tube 371 is detachably sealed with a cap 36. This design allows the impurities on the lower side of the sedimentation tube 371 to be cleaned by removing the cap 36 during actual use, preventing excessive backflow of impurities from the lower side of the sedimentation tube 371 into the return pipe 372, which could cause the filter screen I 35 to become clogged.

[0040] It should be noted that after the oil enters the bypass pipe 37, some of the oil will still pass through the filter screen II 321 and return to the transformer body 1 through the outlet II 311. At this time, part of the oil that enters the mounting housing 31 passes through the through hole 313, enters the inlet III 314 through the bypass pipe 37, and then returns to the mounting housing 31; the other part of the oil passes through the filter screen II 321, mixes with the above-mentioned oil, and then passes through the outlet II 311 together to return to the transformer body 1.

[0041] Therefore, to ensure the cleanliness of the oil returning to the mounting housing 31 via the bypass pipe 37, a filter screen I 35 is installed inside the section of the bypass pipe 37 near the inlet III 314 (return pipe 372). In actual operation, the oil enters the bypass pipe 37 through the through hole 313, forming a vortex at the bend at the bottom of the bypass pipe 37 (bottom of the sedimentation pipe 371). After impurities settle, the oil enters another section of the bypass pipe 37. In this loop, the oil is filtered by the filter screen I 35 inside the other section of the bypass pipe 37 before returning to the mounting housing 31.

[0042] like Figure 4 As shown, in order to ensure that the position of filter screen I 35 is fixed, a corresponding compression spring is provided on the side of filter screen I 35 away from the return pipe 372. The two axial ends of the compression spring abut against the filter screen I 35 and the inner wall of the sedimentation pipe 371, respectively.

[0043] It is important to emphasize that, according to the flow characteristics of liquids, liquids always flow from high-pressure areas to low-pressure areas. Therefore, in order to achieve the flow of oil to the bypass pipe 37 to carry away accumulated impurities, it is necessary to ensure that the oil pressure at the upper end of filter screen II 321 is greater than the oil pressure inside the bypass pipe 37.

[0044] Therefore, this device constrains the initial height of filter screen II 321 to ensure it is not less than the height of through hole 313, and the filter component 32 and the mounting housing 31 are connected by a sealed sliding connection (specifically, a sealing ring capable of elastic deformation, such as a rubber ring, can be fixed to the outside of the filter component 32 or the inner wall of the mounting housing 31 to achieve a sealed sliding connection). This ensures that the oil at the upper end of filter screen II 321 will not be directly connected to the oil in the inner cavity of bypass pipe 37, thereby creating a pressure difference between them (in this state, the inner cavity of bypass pipe 37 and the portion of mounting housing 31 located below filter screen II 321 are directly connected through through hole 313 and inlet hole 3, and the oil pressure in the inner cavity of bypass pipe 37 and the lower side of filter screen II 321 is less than the oil pressure on the upper side of filter screen II 321).

[0045] It should be further explained that when filter screen II 321 moves downward under downward pressure, given the incompressible nature of oil (according to Pascal's Law, even though a liquid is incompressible, pressure can still propagate within it and produce different pressure effects at different locations), the space above filter screen II 321 increases as it moves downward. At this time, the oil pressure on the upper side of filter screen II 321 will inevitably decrease accordingly. However, in this state, the oil pressure on the upper side of filter screen II 321 is still greater than the oil pressure inside the bypass pipe 37 and on the lower side of filter screen II 321 (because the filter component 32 and the mounting housing 31 are a sealed sliding connection, there must be a large frictional resistance between them; therefore, only when the pressure difference between the upper and lower sides of filter screen II 321 is large enough can filter screen II 321 overcome the frictional resistance and move downward under downward pressure).

[0046] It is important to emphasize that during the downward movement of filter screen II 321, because the oil is incompressible, the oil on the lower side of filter screen II 321 will inevitably move upward relative to filter screen II 321. During this process, the upward-moving oil will impact filter screen II 321, thus creating a backwashing effect. The pressure imbalance between the upper and lower sides of filter screen II 321 during this backwashing process generates a squeezing effect that causes adhering substances to peel off the surface of filter screen II 321, thereby improving the removal efficiency of impurities.

[0047] In addition, to ensure that the downward movement distance of the filter element 32 is sufficient to make the height of the filter element 32 less than the height of the through hole 313, this device limits the upper end face of the filter element 32 and the upper end face of the through hole 313 to the same horizontal plane.

[0048] Please refer to Figure 2 , Figure 3To ensure the continuous use of the device and that it can be used multiple times without relying on external forces (i.e., active cleaning by the operator) in practical applications, and to maintain the filter screen II 321 from clogging over a long period, a compression spring 34 is coaxially installed at the lower end of the filter component 32. The two axial ends of the compression spring 34 abut against the filter component 32 and the lower inner wall of the mounting housing 31, respectively. This action ensures that once the oil pressure on the upper side of filter screen II 321, the inner cavity of bypass pipe 37, and the lower side of filter screen II 321 reaches equilibrium (when filter screen II 321 moves downward to the same horizontal plane as through hole 313, oil will flow from the upper end of filter screen II 321 into bypass pipe 37, and the oil inside bypass pipe 37 will participate in the circulation process. During this process, the oil pressure at the upper end of filter screen II 321 gradually decreases, while the oil pressure in the inner cavity of bypass pipe 37 and the lower side of filter screen II 321 gradually increases until the oil pressure at both ends of filter screen II 321 reaches equilibrium), the compression spring 34 releases the accumulated elastic pressure, causing filter screen II 321 to move upward.

[0049] It should be noted that, under normal conditions, the downward pressure Fa on the upper end of filter screen II 321 is equal to the supporting force Fb of the compression spring 34 on the lower end of filter screen II 321 and the static frictional resistance Fc between the filter component 32 and the mounting housing 31. Subsequently, as the accumulation and attachment of material on the upper end of filter screen II 321 gradually increases, Fa becomes greater than the sum of Fb and Fc. At this point, the filter component 32 (filter screen II 321) moves downward. During this process, because the static friction coefficient of the corresponding sealing ring is greater than its dynamic friction coefficient, Fa is much greater than Fb and Fd (the dynamic frictional resistance between the filter component 32 and the inner wall of the mounting housing 31), and the filter component 32 moves downward a certain distance. At the same time, as the downward distance of the filter component 32 increases, the elastic potential energy Fb accumulated by the compression spring 34 gradually increases, and the downward pressure Fa on the upper end of filter screen II 321 decreases until Fa equals the sum of Fb and Fd, at which point the filter component 32 stops moving. At this time, the height of the upper end face of the filter component 32 is less than the height of the upper end face of the through hole 313, and the inner cavity of the bypass pipe 37 is connected to the upper space of the filter screen II 321.

[0050] Accordingly, when the inner cavity of the bypass pipe 37 is connected to the upper space of filter screen II 321, in the initial stage, the oil pressure in the inner cavity of the bypass pipe 37 and the lower side of filter screen II 321 is less than the oil pressure Fa on the upper side of filter screen II 321. Subsequently, as the oil flows and mixes, the sum of Fe (the oil pressure in the inner cavity of the bypass pipe 37 and the lower side of filter screen II 321) and Fb equals the sum of Fa and Fc (at this time, the filter element 32 remains stationary). Finally, as the oil flows and mixes further, Fe is approximately equal to Fa (the presence of filter screen I 35 makes Fe slightly less than Fa, but because filter screen I 35 is small in size and located far away, its blocking effect on the water is limited, so the difference between Fe and Fa is small). At this point, Fb is greater than Fc, so the filter element 32 moves upward, and during the upward movement of the filter element 32, Fc is converted into Fd. Therefore, the automatic reset of the filter element 32 can be achieved by using the compression spring 34, thereby ensuring that the device can be used for a long time and multiple times.

[0051] Please refer to Figure 3 , Figure 4 Furthermore, the device has a through hole 313 on the side of the mounting housing 31, and control valves 33 are installed inside both the through hole 313 and the liquid outlet II 311. Among them, the control valve 33 inside the through hole 313 is control valve I 331, and the control valve 33 inside the liquid outlet II 311 is control valve II 332.

[0052] Specifically, the setting of control valve I331 can further prevent the sealing effect between filter component 32 and mounting housing 31 from failing, and avoid the oil pressure causing the oil to squeeze the sealing ring, thereby causing the sealing ring to undergo elastic deformation.

[0053] Specifically, the control valve II 332 restricts the size of the flow channel for oil to return from outlet II 311 to the inner cavity of transformer body 1. In practical applications, when the filter element 32 moves downward, the opening channel of control valve II 332 can be narrowed, allowing the oil at the lower end of filter screen II 321 and the inner cavity of bypass pipe 37 to quickly reach a pressure balance with the oil at the upper end of filter screen I 35. This allows for rapid reset of the filter element 32, ensuring a sufficiently quick cleaning process and preventing the filter element 32 from obstructing the circulation of oil in the inner cavity of transformer body 1 for an extended period.

[0054] Therefore, in actual operation, the opening and closing states of control valve I 331 and control valve II 332 must be completely opposite to match the movement state of filter component 32.

[0055] Accordingly, control valve II 332 should remain open to ensure the direction of oil flow, that is, the oil can flow from the upper end of filter screen II 321 into the inner cavity of bypass pipe 37.

[0056] Specifically, please refer to Figure 7 The control valve 33 includes a positioning ring 3302 fixedly connected to the mounting housing 31, and one side of the positioning ring 3302 is rotatably connected to the drive ring 3304 on the same axis.

[0057] Meanwhile, multiple positioning grooves 3303 are formed through the positioning ring 3302, and these positioning grooves 3303 are arranged at equal intervals around the central axis of the drive ring 3304. In addition, multiple drive grooves 3305 are also formed through the drive ring 3304, and the multiple drive grooves 3305 correspond one-to-one with the multiple positioning grooves 3303.

[0058] Furthermore, a follower rod 3306 is inserted into both the positioning groove 3303 and the corresponding drive groove 3305, and a baffle plate 3307 is sleeved on the outer side of each follower rod 3306. Therefore, in practical applications, by ensuring that the center line of each positioning groove 3303 coincides with the radius line of the drive ring 3304, and that the distances between the two ends of each drive groove 3305 and the central axis of the drive ring 3304 are not equal, and that the inner wall of each drive groove 3305 has a smooth transition, the contact position between the follower rod 3306 and the drive ring 3304 can be changed by rotating the drive ring 3304, thereby changing the distance between the follower rod 3306 and the central axis of the drive ring 3304. This allows control over the distance between the baffle plate 3307 and the central axis of the drive ring 3304.

[0059] Based on the above principle, this device stipulates that when multiple baffles 3307 abut against each other, the projection of the multiple baffles 3307 on the vertical plane completely covers the projection of the positioning ring 3302 and the central aperture of the drive ring 3304 on the vertical plane. That is, at this time, the multiple baffles 3307 can block the through hole 313 or the liquid outlet II 311. Correspondingly, in this state, rotating the drive ring 3304 can increase the distance between the baffles 3307 and the central axis of the drive ring 3304, thereby eliminating the abutting effect between the baffles 3307 and realizing the opening and closing of control valve I 331 and control valve II 332.

[0060] Therefore, this device specifies that the drive ring 3304 is connected to the filter component 32 in a transmission manner. This enables the filter component 32 to move up and down in conjunction with the opening and closing states of control valve I 331 and control valve II 332, thereby achieving the automatic opening and closing of control valve I 331 and control valve II 332.

[0061] It should be noted that in practical applications, to reduce the frictional resistance experienced by the follower rod 3306 during its movement and to prevent the drive ring 3304 from requiring a large driving force to rotate (i.e., to prevent the resistance encountered by the drive ring 3304 during rotation from affecting its downward movement), as shown in the figure, the follower rod 3306 is constrained to a cylindrical structure. Therefore, to prevent the follower rod 3306 from causing the baffle plate 3307 to rotate, this device specifies that the baffle plate 3307 is slidably connected to the positioning ring 3302. That is, as shown in the figure, a corresponding limiting rod is fixedly connected to the baffle plate 3307, and a corresponding limiting groove is provided on the positioning ring 3302 for the limiting rod.

[0062] Furthermore, to improve the sealing effect of control valve I 331 on through hole 313 and control valve II 332 on outlet II 311, such as Figure 7 As shown, this device has positioning rings 3302 on both sides of the drive ring 3304. The two positioning rings 3302 can form a complex narrow flow channel, thereby achieving a seal. At the same time, the two positioning rings 3302 also enhance the restraining effect on the follower rod 3306, ensuring that the movement path of the follower rod 3306 meets expectations.

[0063] Please refer to Figure 5 , Figure 6 The specific structure shown, in detail, involves two tension springs 3301 carefully arranged on the side end of each drive ring 3304. One end of each of these tension springs 3301 is movably connected to the drive ring 3304. This design cleverly utilizes the characteristics of the tension springs 3301 to achieve a transmission connection between the filter component 32 and the drive ring 3304. This transmission connection method is not only simple in structure but also highly efficient, effectively transmitting power.

[0064] Of the two tension springs 3301 corresponding to each drive ring 3304, we name one tension spring 3301 as tension spring I 33011 and the other tension spring 3301 as tension spring II 33012. The other end of tension spring I 33011 is movably connected to the mounting housing 31, ensuring that tension spring I 33011 can flexibly extend and retract during movement; while the other end of tension spring II 33012 is movably connected to the filter component 32, so that tension spring II 33012 can extend and retract accordingly as the filter component 32 moves.

[0065] In actual operation, when the filter element 32 moves downward, it pulls the extension of the tension spring II 33012 connected to it. The extension of the tension spring II 33012 achieves force transmission. Specifically, during the downward movement of the filter element 32, the rotation direction of the drive ring 3304 is influenced by both the position of the tension spring II 33012 and the shape of the drive groove 3305. This structural design is quite common in existing technology, so it will not be elaborated upon further here.

[0066] It is worth mentioning that this design cleverly utilizes the elastic deformation characteristics of the tension spring 3301. Through the extension and contraction of the tension spring 3301, precise control of the opening and closing of control valve I 331 and control valve II 332 can be achieved. This control method not only has a fast response speed but also high control accuracy, greatly improving the overall performance and working efficiency of the system.

[0067] Furthermore, please refer to Figure 5 To ensure that control valve II 332 responds quickly during the downward movement of filter element 32 and effectively seals the liquid flow channel, this device specifies that when control valve II 332 is in the open state, the corresponding tension spring I 33011 is in the stretched state, and control valve I 331 tends to close under the action of tension spring I 33011. Simultaneously, the corresponding tension spring II 33012 of control valve I 331 abuts against filter element 32 (e.g., ...). Figure 5 As shown, a corresponding driven rod extends from the side end of the filter component 32. The driven rod is inserted into the spring coil at the end of the tension spring II 33012 to achieve a movable connection between the two. When the driven rod moves downward, it abuts against the lower side of the inner spring coil at the end of the tension spring II 33012, thereby driving it to move downward. Under normal conditions, the spring coils in the middle section of the tension spring II 33012 are all in abutting state with each other. This allows the driven rod to abut against the lower side of the spring coil in the middle of the tension spring II 33012, thereby suppressing its movement and counteracting the elastic potential energy released by the tension spring I 33011.

[0068] It should be pointed out that, as Figure 2 As shown, the filter element 32 has a certain thickness, and its lower end face is at the same horizontal plane as the upper end face of the outlet II 311. This allows the filter element 32 to block the outlet II 311 by moving it downwards by a certain distance. This, combined with the opening and closing principle of the control valve II 332, ensures that in actual operation, as the filter element 32 moves downwards, the outlet II 311 responds quickly, reducing the liquid outlet channel.

[0069] Based on the above principles, please refer to Figure 3 , Figure 4This device has a one-way valve 38 installed inside the liquid inlet III 314. The presence of the one-way valve 38, in conjunction with the rapid response of the control valve II 332, ensures that during the downward movement of the filter element 32, the total amount of oil on the lower side of the filter screen II 321 does not decrease rapidly due to pressure; that is, the oil pressure on the lower side of the filter screen II 321 can rise rapidly. This, combined with the movement trajectory of the filter screen II 321, ensures that the oil on the lower side of the filter screen II 321 can provide sufficient backwashing effect.

[0070] Meanwhile, the one-way valve 38 ensures that the oil pressure inside the bypass pipe 37 is at a minimum during the downward movement of the filter component 32. This measure ensures that after the control valve I 331 is opened, the oil can carry impurities into the bypass pipe 37.

[0071] Specifically, during the downward movement of the filter element 32, the filter element 32 compresses the oil on the lower side of filter screen II 321, causing the oil pressure on the lower side of filter screen II 321 to increase, while the oil pressure on the upper side of filter screen II 321 decreases (due to continuous oil injection, the oil pressure on the upper side of filter screen II 321 decreases slightly). During this process, as the filter element 32 moves downward, control valve I 331 opens and control valve II 332 closes. Therefore, the oil carrying impurities flows into the bypass pipe 37, where the impurities settle.

[0072] Correspondingly, when the oil pressure on both sides of filter screen II 321 reaches equilibrium, the elastic potential energy stored in compression spring 34 is released. As filter screen II 321 moves upward, control valve II 332 opens, accelerating the exchange rate between the oil on the lower side of filter screen II 321 and the oil in the inner cavity of transformer body 1, thus reducing the oil pressure on the lower side of filter screen II 321. During this process, control valve I 331 closes, and the oil inside bypass pipe 37 maintains a higher pressure under this state. As the oil pressure inside filter screen II 321 gradually decreases, check valve 38 opens intermittently, causing intermittent exchange between bypass pipe 37 and the oil on the lower side of filter screen II 321. This process causes the oil pressure inside bypass pipe 37 and the lower side of filter screen II 321 to remain at a lower level for an extended period.

[0073] In practical applications, the increase in oil pressure inside filter screen II 321 and bypass pipe 37 varies depending on the falling distance of filter component 32. Combined with the damping effect of the oil, the opening speed of control valve II 332 will also differ. When filter component 32 resets upward at a relatively fast speed, the oil pressure inside filter screen II 321 decreases rapidly. When the oil inside bypass pipe 37 flows downward to the lower side of filter screen II 321 at a relatively fast speed, the impact of the oil on check valve 38 will also cause check valve 38 to remain open until the bypass pipe 37 and the lower side of filter screen II 321 maintain approximately the same oil pressure (the specific situation depends on the minimum resistance set of the selected model of check valve 38; the smaller the minimum resistance set, the smaller the pressure difference between bypass pipe 37 and filter screen II 321 after filter component 32 resets).

[0074] Furthermore, to ensure that the pressure difference between the bypass pipe 37 and the filter screen II 321 is at a minimum after the filter component 32 is reset, so that the oil pressure on the upper side of the filter screen II 321 can quickly rush into the bypass pipe 37 during subsequent cleaning processes, the constraint check valve 38 of this device includes a sealing plate 381 disposed above the liquid inlet III 314. Utilizing the characteristic that the projection of the sealing plate 381 on the horizontal plane completely covers the liquid inlet III 314, when the sealing plate 381 is subjected to downward pressure, the flow direction of the liquid can be suppressed by the action of the sealing plate 381 abutting against the inner wall of the mounting housing 31. When the sealing plate 381 is subjected to upward pushing force, the pivot 382 causes the sealing plate 381 to form a rotatable connection with the lower inner wall of the mounting housing 31, thereby realizing the opening of the sealing plate 381. This method relies solely on the cooperation between the sealing plate 381 and the pivot 382 to realize the function of the one-way valve 38, ensuring that the opening and closing of the sealing plate 381 is only affected by the resistance pressure on its upper and lower sides (the sealing plate 381 is also subject to a certain frictional resistance, that is, due to the high damping characteristics of the oil, there is frictional resistance between the sealing plate 381 and the oil, but this frictional resistance is small and can be ignored), thereby ensuring that the pressure difference between the bypass pipe 37 and the filter screen II 321 is at a minimum value.

[0075] Please refer to Figure 6 To ensure a significant pressure difference between the oil on the upper side of filter screen II 321 and the oil inside the bypass pipe 37 during the downward movement of filter component 32, this device stipulates that when control valve I 331 is closed, the corresponding tension springs I 33011 and II 33012 are both in a stretched state. Furthermore, control valve I 331 has a tendency to close under the action of tension spring I 33011. Therefore, filter component 32 must move downward a certain distance (during which control valve II 332 is closed, and oil continues to flow into the mounting housing 31) before control valve I 331 opens, thereby increasing the pressure difference between the oil on the upper side of filter screen II 321 and the oil inside the bypass pipe 37.

[0076] It should be emphasized that as the filter element 32 moves downward, the area of ​​the filter element 32 covering the through hole 313 gradually decreases. Combined with the opening and closing principle of the control valve I 331, this ensures that a large flow channel can be quickly formed during the opening of the control valve I 331. This guarantees that the exchange rate between the oil on the upper side of the filter screen II 321 and the oil inside the bypass pipe 37 is sufficient to remove impurities from the upper side of the filter screen II 321 and achieve a rapid pressure balance.

[0077] Please refer to Figure 8 , Figure 9 Specifically, the filter component 32 includes a housing 322, and a filter screen II 321 is installed on the upper side of the housing 322. This method utilizes the thickness of the housing 322 itself to achieve normal sealing of the through hole 313 and temporary sealing of the liquid outlet II 311.

[0078] Furthermore, to enhance the effectiveness of this device in removing deposits from the surface of filter screen II 321, multiple contact plates 323 are rotatably connected inside the outer casing 322. These contact plates 323 are arranged at equal intervals around the central axis of the outer casing 322. In this case, the device limits the maximum distance between the side end of each contact plate 323 and its central axis to be greater than the distance between its central axis and the lower end face of filter screen II 321. Thus, by rotating the contact plate 323 (i.e., keeping the contact plate 323 vertical), it can abut against the lower end face of filter screen II 321, thereby applying an upward thrust to filter screen II 321.

[0079] Accordingly, during use, the upward pushing force applied by the contact plate 323 to the filter screen II 321 can be removed by rotating the contact plate 323, causing the filter screen II 321 to produce elastic vibration or elastic fluctuation (determined by the structural characteristics of the filter screen II 321 itself, its mesh surface can produce elastic deformation), thereby achieving the effect of separating impurities from the filter screen II 321.

[0080] Specifically, in order to facilitate the automatic cleaning of filter screen II 321, this device is equipped with a return spring 324 on the side of each contact plate 323. The two axial ends of the return spring 324 are respectively movably connected to the corresponding contact plate 323 and the inner wall of the outer casing 322.

[0081] Therefore, this device stipulates that when the return spring 324 is not subjected to external force, the contact plate 323 does not contact the filter screen II 321. This ensures that, under normal conditions, the oil remains vertical due to the impact of the oil flow on the contact plate 323. However, when excessive impurities accumulate on the surface of the filter screen II 321, reducing its flowability and decreasing the oil flow rate below the filter screen II 321, the return spring 324 can pull the contact plate 323 to rotate, thereby removing the upward pushing force applied to the filter screen II 321.

[0082] It is important to emphasize that, in this device, when the return spring 324 is not affected by external force, that is, when the contact plate 323 is not affected by oil impact and the return spring 324 releases its elastic potential energy (i.e., the filter screen II 321 is blocked and the contact plate 323 removes its upward pushing force on the filter screen II 321), the angle between the upper end face of the contact plate 323 and the horizontal plane is greater than 0° and less than 90°. This allows both the upper and lower end faces of the contact plate 323 to have a certain tilt angle, so that when the oil impacts the contact plate 323, it can counteract the return spring 324, thereby allowing the contact plate 323 to re-abut against the filter screen II 321 and provide an upward pushing force to the filter screen II 321.

[0083] It is important to emphasize that, under normal conditions, the impact force exerted by the oil on the contact plate 323 keeps it vertical. At this time, the contact plate 323 exerts an upward thrust on the filter screen II 321 (the filter screen II 321 undergoes elastic deformation). Subsequently, as impurities accumulate on the filter screen II 321, the oil flow rate below the filter screen II 321 decreases. The return spring 324 releases its elastic potential energy, and the contact plate 323 returns from a vertical to a horizontal state. At this point, the upward thrust on the filter screen II 321 disappears, the elastic deformation of the filter screen II 321 recovers, and the filter screen II 321 produces elastic vibration or elastic fluctuation. Then, the downward pressure on the filter screen II 321 continues to increase, and the filter component 32 moves downward. At this time, the oil below the filter screen II 321 pushes the contact plate 323 to rotate (the return spring 324 extends and accumulates elastic potential energy), and the contact plate 323 again applies an upward thrust to the filter screen II 321.

[0084] The specific operation process of this invention in practical applications is as follows: I. Normal working status 1. Filter status: Filter II 321 performs its filtering function, effectively trapping impurities in the oil on its upper end face. The filtered oil flows back into the transformer body through the outlet II 311.

[0085] 2. Contact plate 323: The impact force of the oil keeps the contact plate 323 in a vertical position, making close contact with the lower end face of filter screen II 321 and applying an upward thrust, causing filter screen II 321 to undergo elastic deformation; at the same time, the return spring 324 is in a stretched state.

[0086] 3. Control valve 33: Control valve II 332 (corresponding to outlet II 311) is kept open under normal circumstances to ensure smooth flow of oil; while control valve I 331 (corresponding to through hole 313) is closed to block the connection between bypass pipe 37 and the upper side of filter screen II 321.

[0087] 4. Check valve 38: The check valve 38 in the inlet III 314 is in the closed state, and the sealing plate 381 covers the inlet III 314 to prevent the oil in the bypass pipe 37 from flowing back.

[0088] 5. Pressure balance: The pressure (Fa) on the upper side of filter screen II 321 is equal to the sum of the supporting force (Fb) provided by the compression spring 34 and the static friction resistance (Fc), so that the filter assembly remains stationary.

[0089] II. Impurity Accumulation Stage 1. Impurity accumulation and decreased flowability: The amount of impurities at the upper end of filter screen II 321 increases, the flow area decreases, a pressure difference is formed between the upper and lower sides, and the oil flow rate at the lower side of filter screen II 321 decreases.

[0090] 2. Contact plate 323 rotates: The impact force of the oil on the contact plate 323 is reduced, the return spring 324 releases elastic potential energy, pulls the contact plate 323 to rotate to an inclined state, and removes the upward pushing force on the filter screen II 321.

[0091] 3. Filter screen vibration removes impurities: The elastic deformation of filter screen II321 recovers, generating vibration or fluctuation, which removes some of the attached substances from the surface.

[0092] 4. Triggering downward movement condition: The downward pressure (Fa) on the upper side of filter screen II 321 gradually increases. When Fa > Fb (the upward thrust applied by the compression spring 34 to the filter element 32) + Fc (the static frictional resistance between the filter element 32 and the mounting housing 31), the filter element 32 begins to move downward against the static friction.

[0093] III. Filter element relocation stage 1. Secondary rotation mechanism of contact plate 323: During the downward movement of the filter element, it exerts a squeezing effect on the lower oil, causing the oil pressure to increase and impact the contact plate 323, thereby pushing the contact plate 323 to rotate to a vertical position. The return spring 324 is then stretched, storing potential energy.

[0094] 2. Control valve 33 linkage mechanism: a. Rapid closing of control valve II 332: When the filter element moves downward, it pulls the tension spring II 33012 corresponding to control valve II 332 downward. At the same time, the tension spring I 33011 corresponding to control valve II 332 releases its stored elastic potential energy, driving the drive ring 3304 to rotate rapidly. Under the drive of the drive ring 3304, the baffle plate 3307 moves towards the central axis, rapidly narrowing the channel of the outlet II 311, thereby achieving rapid closing of control valve II 332.

[0095] b. Delayed opening of control valve I 331: During the downward movement of the filter element, the tension spring II 33012 corresponding to control valve I 331 moves downward with the driven rod, but it needs to overcome the elastic potential energy stored in the tension spring I 33011 corresponding to control valve I 331 (at this time, both tension springs I 33011 and II of control valve I 331 are in a stretched state, and tension spring I 33011 has a closing tendency). When the filter element moves down to a specific distance, the tension of tension spring II 33012 overcomes the resistance of tension spring I 33011, and the drive ring 3304 starts to rotate, driving the baffle plate 3307 away from the central axis, thus realizing the delayed opening of control valve I 331.

[0096] 3. Start rinsing: The oil on the upper side of filter screen II 321 enters the bypass pipe 37 through the through hole 313, forming a vortex at the bottom of the V-shaped sedimentation pipe 371, where impurities settle; the pressure (Fe) inside the bypass pipe 37 gradually increases due to the continuous inflow of oil.

[0097] 4. Filter element 32 stops moving: The oil pressure under the filter screen II 321 is increased by compression, and it works together with the pressure of the bypass pipe 37 until a dynamic equilibrium state Fa≈Fe (oil pressure in the cavity of the bypass pipe 37 and the oil pressure under the filter screen II 321)+Fb is reached. At this time, the filter element stops moving downward.

[0098] 5. One-way valve 38 state analysis: The filter element moves downward, squeezing the oil under filter screen II 321, and the oil pressure under one-way valve 38 continuously increases. When the pressure under one-way valve 38 is greater than the pressure on the upper side, the sealing plate 381 is pushed upward and rotates around the pivot 382, ​​and one-way valve 38 opens. At this time, the oil on the upper layer of filter screen II 321 forms a bidirectional flow path: part of it enters the bypass pipe 37 through the through hole 313 and then returns to the mounting housing 31, and the other part directly passes through filter screen II 321 and enters the space under filter screen II 321.

[0099] IV. Reset Stage of Filter Component 32 1. Triggering Reset: The compression spring 34 accumulates elastic potential energy during the downward movement of the filter component 32. When the supporting force (Fb) of the compression spring 34 is greater than the static friction resistance (Fc), it pushes the filter component 32 to overcome the static friction and reset upward.

[0100] 2. Control valve 33 reverses state: The filter element 32 moves upward, causing the tension spring II 33012 to reset, the drive ring 3304 rotates in the opposite direction, control valve II 332 opens (restoring oil flow), and control valve I 331 closes (blocking the bypass pipe 37 from connecting to the upper side of filter screen II 321).

[0101] 3. One-way valve 38 opening and oil return: When the pressure on the lower side of filter screen II 321 decreases, the one-way valve 38 sealing plate 381 is opened by the upward thrust around the pivot 382. The clean oil in the bypass pipe 37 flows back to the mounting housing 31 after being filtered by filter screen I 35, and mixes with the oil on the lower side of filter screen II 321.

[0102] 4. Restore normal operation: The filter component 32 returns to its initial position, the contact plate 323 remains vertical, the filter screen II 321 resumes its filtering function, and waits for the next impurity accumulation to trigger the cycle.

[0103] Core logic: Through the linkage of mechanical structure (filter component 32, control valve 33, contact plate 323) and fluid pressure changes, the filter screen can be automatically cleaned and cyclically reset without manual intervention.

[0104] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A power transformer with self-cleaning function, comprising a transformer body equipped with an oil circulation mechanism and a filtration mechanism, wherein the inlet I of the oil circulation mechanism and the outlet II of the filtration mechanism are connected to the inner cavity of the transformer body, and the outlet I of the oil circulation mechanism is connected to the inlet II of the filtration mechanism, characterized in that: The filtration mechanism includes a mounting housing with vertical axial dimensions, and the liquid inlet II is located at the upper end of the mounting housing, while the liquid outlet II is located at the side end of the mounting housing. A bypass pipe is provided on one side of the mounting housing. The upper opening of the bypass pipe is connected to the through hole on the side of the mounting housing, and the lower opening of the bypass pipe is connected to the liquid inlet III at the bottom of the mounting housing. Furthermore, a filter screen I is provided inside the section of the bypass pipe near the liquid inlet III. The mounting housing is internally sealed and slidably connected with a filter component. The filter component moves vertically relative to the mounting housing. The filter component includes a filter screen II. In the initial state, the height of the upper end face of the filter component is not less than the height of the upper end face of the through hole. However, as the filter component moves downward, the height of the upper end face of the filter component becomes less than the height of the upper end face of the through hole. A compression spring is coaxially mounted at the lower end of the filter component, and the other axial end of the compression spring abuts against the mounting housing.

2. A power transformer with self-cleaning function according to claim 1, characterized in that: The through hole and the liquid outlet II are equipped with control valves. The through hole is equipped with control valve I, and the liquid outlet II is equipped with control valve II. The opening and closing states of control valve I and control valve II are completely opposite, and control valve II is kept in the normally open state. When the filter element moves downward, control valve I opens.

3. A power transformer with self-cleaning function according to claim 2, characterized in that: The control valve includes a positioning ring fixedly connected to the mounting housing, and a drive ring rotatably connected to one side of the positioning ring. The drive ring is connected to the filter component in a transmission connection. The positioning ring has multiple positioning slots that are equidistantly arranged around the central axis of the drive ring, and the center line of each positioning slot coincides with the radius line of the drive ring. Each of the drive rings has multiple drive grooves through it, and the multiple drive grooves correspond one-to-one with multiple positioning grooves. Furthermore, the distances between the two ends of each drive groove and the central axis of the drive ring are not equal, and the inner wall of each drive groove is smoothly transitioned. Each positioning slot and its corresponding driving slot are connected together by a follower rod. Each follower rod is fitted with a baffle plate on its outer side, and the baffle plate is slidably connected to the positioning ring. When the multiple barrier plates abut against each other, the projection of the multiple barrier plates on the vertical plane completely covers the projection of the positioning ring and the center aperture of the drive ring on the vertical plane.

4. A power transformer with self-cleaning function according to claim 3, characterized in that: Each drive ring is provided with two tension springs on its side end. One end of the tension spring is movably connected to the drive ring. At the same time, of the two tension springs corresponding to each drive ring, the tension spring whose other end is movably connected to the mounting housing is tension spring I, and the tension spring whose other end is movably connected to the filter component is tension spring II. When the control valve I is in the closed state, the tension springs I and II corresponding to the control valve I are both in the stretched state, and the control valve I has a tendency to close under the action of tension spring I.

5. A power transformer with self-cleaning function according to claim 4, characterized in that: When the control valve II is in the open state, the tension spring I corresponding to the control valve II is in the stretched state, and the control valve I has a tendency to close under the action of the tension spring I. At the same time, the tension spring II corresponding to the control valve I abuts against the filter component.

6. A power transformer with self-cleaning function according to claim 5, characterized in that: The liquid inlet III is equipped with a one-way valve. The one-way valve includes a sealing plate located on the upper side of the liquid inlet III. The sealing plate is rotatably connected to the lower inner wall of the mounting housing via a pivot.

7. A power transformer with self-cleaning function according to claim 1, characterized in that: The filter component includes an outer shell, inside which are rotatably connected multiple contact plates with a horizontal central axis. The multiple contact plates are equidistantly arranged around the central axis of the outer shell, and the maximum distance between the side end of each contact plate and its central axis is greater than the distance between its central axis and the lower end face of the filter screen II. Each of the contact plates is provided with a return spring on its side end. The two axial ends of the return spring are movably connected to the corresponding contact plate and the inner wall of the outer casing, respectively. When the return spring is not affected by external force, the contact plate does not contact the filter screen II.

8. A power transformer with self-cleaning function according to claim 7, characterized in that: When the reset spring is not affected by external force, the angle between the upper surface of the contact plate and the horizontal plane is greater than 0° and less than 90°.

9. A power transformer with self-cleaning function according to claim 1, characterized in that: The upper end face of the filter element is at the same horizontal plane as the upper end face of the through hole, and the lower end face of the filter element is at the same horizontal plane as the upper end face of the liquid outlet II.

10. A power transformer with self-cleaning function according to claim 1, characterized in that: The bypass pipe includes a sedimentation pipe, the upper end of which is connected to a through hole, and a return pipe is connected to the side end of the sedimentation pipe. The upper end of the return pipe is connected to the liquid inlet III. Meanwhile, the lower end of the sedimentation pipe has an open structure and a cap is detachably and sealingly connected to the lower end of the sedimentation pipe.

Images