A corrugated expander

Abstract

This invention belongs to the technical field of power distribution equipment accessories, specifically a corrugated expander; it includes a flange; a protective shell installed on the flange; a corrugated core installed on the flange; a guide tube installed at the bottom of the flange; an extension cylinder fixed at the top of the corrugated core; a disc sliding inside the extension cylinder; an adding tube fixed in the middle of the disc; a limiting disc at the top of the disc; the limiting disc located inside the extension cylinder; the adding tube passing through the disc; a guide tube at the bottom of the disc, passing through the corrugated core and extending into the guide tube, and concentrically arranged with the guide tube; uniformly arranged vertical grooves on the outer ring of the guide tube, and the vertical grooves do not penetrate the top and bottom of the guide tube; by setting the extension cylinder and the disc, this invention can reduce the ineffective alternating motion of the corrugated core caused by small daily oil temperature changes, and reduce the cyclic alternating load borne by the corrugated sheets and welded parts.

Description

Technical Field

[0001] This invention belongs to the technical field of power distribution equipment accessories, specifically a corrugated expander. Background Technology

[0002] In power transmission and distribution systems, oil-immersed power transformers, current transformers, voltage transformers, and reactors are core equipment for voltage transformation, energy metering, grid protection, and reactive power compensation. All of these devices use insulating oil as their core insulation and cooling medium. The insulating performance and physicochemical stability of the insulating oil directly determine the operational safety and lifespan of the equipment. During the entire operation cycle, the volume of the insulating oil exhibits significant thermal expansion and contraction characteristics with temperature changes. Extreme temperature differences between winter and summer can reach over 40°C, and in extremely cold or hot regions, the temperature difference can even exceed 60°C. Coupled with the oil temperature fluctuations caused by peak and off-peak load changes in the power grid and start-up and shutdown conditions during daily operation, the volume change of the insulating oil can reach 5%-10% of the total oil volume in the equipment. If the volume change cannot be effectively and stably compensated, it will cause a sudden increase in pressure or a negative pressure state inside the equipment oil tank. In mild cases, it will cause cracking of the oil tank welds and leakage of insulating oil; in severe cases, it will cause external air and moisture to seep into the oil cavity, causing oxidation and deterioration of the insulating oil, a sudden drop in insulation strength, and major power grid safety accidents such as partial discharge inside the equipment, inter-turn short circuits, or even burnout.

[0003] To address the aforementioned issues, metal corrugated expanders (hereinafter referred to as metal expanders), as volume adaptive compensation devices, have become a standard core accessory for current oil-immersed high-voltage electrical equipment. Their core working principle is as follows: Multiple stainless steel corrugated core sections connected in series serve as elastic compensation elements. The oil chamber of the corrugated core is directly connected to the main oil tank of the equipment. When the oil temperature rises and the insulating oil expands, the corrugated core undergoes elastic contraction under oil pressure, expanding the oil chamber volume to accommodate the expanding oil. When the oil temperature decreases and the insulating oil shrinks, the corrugated core elastically elongates under its own elastic force, reducing the oil chamber volume to replenish the shrinking oil, thus achieving dynamic adaptive compensation for changes in the insulating oil volume throughout the entire process.

[0004] However, the design and selection of existing metal bellows expanders are mostly based solely on the maximum volume change corresponding to extreme temperature differences between winter and summer. They only check the maximum compensation volume and rated pressure capacity under extreme working conditions, but ignore the fatigue damage caused by high-frequency alternating expansion and contraction during daily operation. In actual operating conditions, in addition to seasonal large-stroke expansion and contraction, the daily diurnal temperature variation of the equipment and the frequent fluctuations in peak and valley loads of the power grid will cause the oil temperature to rise and fall continuously. This causes the bellows core of the expander to undergo several or even dozens of reciprocating expansions and contractions every day. The bellows and welded joints are subjected to cyclic alternating loads for a long time, and continuous fatigue accumulation is very likely to form at stress concentration locations such as the bellows root and the heat-affected zone of the weld. Long-term alternating loads will cause the elastic properties of stainless steel corrugated sheets to continuously deteriorate, resulting in irreversible plastic deformation. This will cause a significant decrease in the actual compensation volume of the equipment, making it unable to meet the oil temperature change compensation requirements under all operating conditions. At the same time, the repeated action of alternating stress will cause microcracks to initiate in the stress concentration area. These microcracks will continue to expand with the continuous action of alternating loads, eventually leading to cracking of the corrugated sheets and leakage of the welds. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies and solve the above-mentioned technical problems, this invention proposes a corrugated expander. By setting an extension cylinder and a disc, the ineffective alternating motion of the corrugated core caused by small daily oil temperature changes can be reduced, and the cyclic alternating load borne by the corrugated sheets and welded parts can be reduced. The specific structure is as follows. A corrugated expander includes a flange; a protective shell is mounted on the flange; a corrugated core is mounted on the flange and the corrugated core is located inside the protective shell. A conduit is installed at the bottom of the flange, and the conduit is rigidly connected to the top interface of the oil tank; An extension cylinder is fixed to the top of the corrugated core, and the corrugated core is connected to the extension cylinder; a disc slides inside the extension cylinder, and the disc and the extension cylinder are slidably sealed. An adding tube is fixed in the middle of the disc, and the bottom of the adding tube is connected to the space at the bottom of the disc, and the top extends to the top of the protective shell and is slidably connected to the protective shell; an oil injection valve is installed at the top of the adding tube. The top of the disc is provided with a limiting disc, which is used to limit the distance the disc moves upward; the limiting disc is located inside the extension cylinder; the adding tube passes through the limiting disc and is slidably connected to the limiting disc; The bottom of the disc is provided with a guide tube, which passes through the corrugated core and extends into the guide tube, and is concentrically arranged with the guide tube. The outer ring of the guide tube has evenly arranged vertical grooves, and the vertical grooves do not penetrate the top and bottom of the guide tube.

[0006] In a preferred embodiment of the present invention, the guide cylinder rotates on a disk; and uniformly arranged arc-shaped blades are fixed below the vertical groove on the inner ring of the guide cylinder.

[0007] In a preferred embodiment of the present invention, the outer ring of the guide tube has evenly arranged balls that rotate within the inner ring of the guide tube.

[0008] In a preferred embodiment of the present invention, four vertical plates are fixed to the top of the extension tube, and the inner circle of the vertical plates is arc-shaped, and the inner circle diameter of the vertical plates is the same as the inner circle diameter of the extension tube. A cross plate is fixed to all four of the aforementioned upright plates; The limiting disc slides inside the extension cylinder; two threaded rods are fixed to the top of the limiting disc; threaded cylinders are provided at the top of the two threaded rods; The threaded rod is located inside the threaded cylinder and engages with the threaded cylinder thread; The two threaded cylinders pass through the cross plate and are rotatably connected to the cross plate; the two threaded cylinders are located on both sides of the center of the cross plate.

[0009] In a preferred embodiment of the present invention, a first gear is rotatably mounted at the center of the cross plate. The adding tube passes through the inner ring of the first gear and is slidably connected to the first gear; the adding tube passes through the cross plate and is slidably connected to the cross plate. The outer ring surfaces of the two threaded cylinders located above the cross plate are provided with evenly arranged tooth grooves, and the tooth grooves mesh with the first gear.

[0010] As a preferred embodiment of the present invention, a pressure sensor is installed on the top of the protective shell; One of the threaded cylinders is positioned opposite the pressure sensor.

[0011] In a preferred embodiment of the present invention, a second gear is provided above the cross plate, and the second gear and the two threaded cylinders are triangularly distributed; The second gear meshes with the first gear; the second gear is driven by a motor, and the motor is mounted at the bottom of the cross plate.

[0012] In a preferred embodiment of the present invention, a sealing cylinder is provided above the extension cylinder; The sealing cylinder is fixed on four vertical plates; the inner diameter of the sealing cylinder is the same as the inner diameter of the extension cylinder. A limiting cylinder is provided above the cross plate, and the limiting cylinder is fixed on the protective shell; the outer diameter of the vertical plate and the sealing cylinder is the same as the inner diameter of the limiting cylinder, and the vertical plate and the sealing cylinder slide inside the limiting cylinder in the initial state; The outer diameter of the extension tube is the same as the inner diameter of the limiting tube, and in the initial state, the top part of the extension tube slides inside the limiting tube. The limiting cylinder has uniformly arranged liquid grooves around its circumference; the sealing cylinder is initially in contact with the liquid grooves and seals the liquid grooves. The outer ring of the limiting cylinder is provided with an annular compartment, which is fixed to the flange; the opening of the annular compartment is in contact with the limiting cylinder and is opposite to the liquid tank.

[0013] In a preferred embodiment of the present invention, the annular compartment is provided with an annular block, and the top of the annular block is a slope. A first electric actuator is installed on the flange, and the extension rod of the first electric actuator extends into the annular chamber and is fixed on the annular block; Support blocks are fixed on both sides of the outer ring of the extension cylinder; a second electric push rod is installed on the flange below the support block, and the second electric push rod is not in contact with the support block in the initial state. The disc is provided with evenly arranged one-way valves.

[0014] The beneficial effects of this invention are as follows: 1. The corrugated expander of the present invention, by setting an extension cylinder, a sliding sealing disc, and a limiting disc on the top of the corrugated core, enables the expander to buffer and compensate for small oil temperature fluctuations caused by daily diurnal temperature differences and peak and valley loads of the power grid by relying solely on the sliding of the disc within the extension cylinder. This eliminates the need for the corrugated core to immediately participate in high-frequency reciprocating expansion and contraction, significantly reducing the ineffective alternating motion of the corrugated core caused by daily small oil temperature changes, reducing the cyclic alternating load on the corrugated sheets and welded parts, delaying fatigue accumulation in stress concentration areas, inhibiting the initiation and propagation of microcracks, and preventing premature plastic deformation, cracking, and leakage of the corrugated core, effectively extending the overall service life of the expander.

[0015] 2. The corrugated expander of this invention, by rotating the first gear, synchronously drives two threaded cylinders to rotate, which in turn pushes the threaded rod to drive the limiting disc to slide up and down, flexibly adjusting the maximum sliding distance of the disc in the extension cylinder. Thus, according to the temperature difference in different seasons and the temperature difference changes in the equipment operating environment, the effective compensation volume of the extension cylinder can be adjusted, so that the expansion volume of the insulating oil caused by the daily diurnal temperature difference and the peak and valley load fluctuations of the power grid can be completely controlled within the volume range of the extension cylinder. This avoids unnecessary tensioning or contraction of the corrugated core due to daily temperature changes, fundamentally reducing the high-frequency reciprocating expansion and contraction of the corrugated core, reducing the cyclic alternating load on the corrugated sheet and welded parts, alleviating fatigue accumulation in stress concentration areas, inhibiting the initiation and propagation of microcracks, and effectively extending the overall service life of the corrugated core and the expander.

[0016] 3. The corrugated expander of this invention, during the ground contact buffering process of a UAV, when a short circuit fault occurs in the oil tank, the electric arc generated by the short circuit will instantly cause the insulating oil temperature to rise sharply and its volume to expand rapidly, generating instantaneous high pressure. This high pressure will push the extension cylinder, the vertical plate, and the threaded cylinder to move upward rapidly. One of the threaded cylinders opposite the pressure sensor will quickly act on the pressure sensor. After the pressure sensor detects the instantaneous high pressure signal, it controls the limiting plate to move upward rapidly to the position above the liquid tank of the limiting cylinder. At this time, the sealing cylinder moves upward with the vertical plate and separates from the liquid tank, and the liquid tank is unobstructed. The high-pressure insulating oil generated by the short circuit will quickly enter the annular chamber through the liquid tank to achieve instantaneous pressure relief, avoiding the high pressure from acting directly on the corrugated core, preventing the corrugated core from being damaged, cracked, or leaking due to exceeding its pressure bearing capacity, and buying time for equipment fault handling. Attached Figure Description

[0017] The invention will now be further described with reference to the accompanying drawings.

[0018] Figure 1 This is an overall state diagram of the expander of the present invention; Figure 2 This is a diagram of the internal structure of the expander of the present invention; Figure 3 This is a diagram showing the disassembled structure of the expander of the present invention; Figure 4 This is a connection structure diagram of the corrugated core, extension cylinder and sealing cylinder in this invention; Figure 5 This is a top view of the expander of the present invention; Figure 6 This is the present invention. Figure 5 Cross-sectional view at point AA when the expansion tank is working normally; Figure 7 This is the present invention. Figure 6 Enlarged view of a section at point B in the middle; Figure 8 This is the present invention. Figure 6 Enlarged view of a section at point C; Figure 9 This is the present invention. Figure 5 Cross-sectional view of section AA of the intermediate expander under high pressure; Figure 10 This is the present invention. Figure 9 Enlarged view of a section at point D; Figure 11 This is the present invention. Figure 9 Enlarged view of a section at point E in the middle.

[0019] In the diagram: 1. Flange; 11. Protective shell; 12. Corrugated core; 13. Conduit; 2. Extension tube; 21. Disc; 22. Adding tube; 23. Limiting disc; 24. Guide tube; 25. Vertical groove; 26. Arc blade; 3. Vertical plate; 31. Cross plate; 32. Threaded rod; 33. Threaded cylinder; 34. First gear; 35. Pressure sensor; 36. Second gear; 37. Motor; 38. Sealing cylinder; 4. Limiting cylinder; 41. Liquid tank; 5. Annular chamber; 51. Annular block; 52. First electric actuator; 53. Support block; 54. Second electric actuator. Detailed Implementation

[0020] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0021] like Figures 1 to 11As shown, the corrugated expander of the present invention, as an embodiment of the present invention, includes a flange 1; a protective shell 11 is installed on the flange 1; a corrugated core 12 is installed on the flange, and the corrugated core 12 is located inside the protective shell 11. The bottom of the flange 1 is equipped with a conduit 13, and the conduit 13 is rigidly connected to the top interface of the oil tank; The corrugated core 12 is fixed to the top of the extension cylinder 2, and the corrugated core 12 is connected to the extension cylinder 2; a disc 21 slides inside the extension cylinder 2, and the disc 21 and the extension cylinder 2 are slidably sealed. An adding tube 22 is fixed in the middle of the disc 21, and the bottom of the adding tube 22 is connected to the bottom space of the disc 21, and the top extends to the top of the protective shell 11 and is slidably connected to the protective shell 11; an oil injection valve is installed on the top of the adding tube 22. The top of the disc 21 is provided with a limiting disc 23, which is used to limit the upward movement distance of the disc 21; the limiting disc 23 is located inside the extension tube 2; the adding tube 22 passes through the limiting disc 23 and is slidably connected to the limiting disc 23. The bottom of the disc 21 is provided with a guide tube 24, which passes through the corrugated core 12 and extends into the conduit 13, and is concentrically arranged with the conduit 13. The guide cylinder 24 has evenly arranged vertical grooves 25 on its outer ring, and the vertical grooves 25 do not penetrate the top and bottom of the guide cylinder 24.

[0022] During use, when the expander is in normal operation, the oil injection valve is in the closed state to ensure that the inside of the expander is completely isolated from the outside atmosphere, preventing moisture and oxygen from entering and contaminating the insulating oil, while ensuring the sealing performance of the expander; at the same time, the insulating oil in the oil tank fills the cavity between the corrugated core 12 and the extension cylinder 2 and the guide cylinder 24, so that the inside of the corrugated core 12 is filled with insulating oil, realizing synchronous communication with the insulating oil in the equipment oil tank; Specifically, when the expander experiences daily diurnal temperature variations and frequent fluctuations in grid peak and valley loads, the temperature of the insulating oil changes. When the oil temperature rises, the volume of the insulating oil in the tank expands and the pressure increases. This expands through the conduit 13 into the guide cylinder 24, pushing the disc 21 upward along the extension cylinder 2. Simultaneously, this causes the guide cylinder 24 and the adding pipe 22 to extend the protective shell 11 upward until the top of the disc 21 contacts the limiting disc 23. The limiting disc 23 then acts as a stop, preventing the disc 21 from moving further upward. If the insulating oil continues to enter the expander at this point, the corrugated core 12 will be stretched. When the insulating oil stops entering the expander, the corrugated core 12 stops stretching, thus limiting excessive expansion and contraction of the corrugated core 12. To avoid stress concentration caused by excessive stretching of the corrugated core 12 and reduce damage from alternating loads, the expansion and contraction of the corrugated core 12 matches the expansion of the insulating oil, dynamically compensating for changes in oil volume, maintaining stable internal pressure, and preventing leakage caused by excessive pressure. When the oil temperature decreases, the volume of the insulating oil shrinks, the internal pressure decreases, and the insulating oil inside the expander returns to the oil tank, thereby driving the disc 21 to move downward. If the disc 21 moves to the bottom of the extension cylinder 2 and the insulating oil continues to flow into the oil tank, the corrugated core 12 contracts axially downward under its own elastic force, simultaneously driving the extension cylinder 2 to move downward. When the insulating oil no longer flows back into the oil tank, the corrugated core 12 stops contracting.

[0023] More specifically, due to the presence of the guide tube 24, the guide tube 24 can guide the incoming insulating oil, so that the insulating oil can enter and exit the corrugated core 12 evenly, avoiding uneven oil flow that could cause local overload of the corrugated core 12; at the same time, the oil is replenished to the inside through the addition tube 22 without affecting the normal compensation function of the expander.

[0024] Furthermore, by setting an extension cylinder 2, a sliding sealing disc 21, and a limiting disc 23 on the top of the corrugated core 12, the expander can buffer and compensate for oil volume changes simply by sliding the disc 21 within the extension cylinder 2 when dealing with small oil temperature fluctuations caused by daily day-night temperature differences and peak-valley loads of the power grid. This eliminates the need for the corrugated core 12 to immediately participate in high-frequency reciprocating expansion and contraction, significantly reducing the ineffective alternating motion of the corrugated core 12 caused by daily small oil temperature changes, reducing the cyclic alternating load on the corrugated sheets and welded parts, delaying fatigue accumulation in stress concentration areas, inhibiting the initiation and propagation of microcracks, and preventing premature plastic deformation, cracking, and leakage of the corrugated core 12, thus effectively extending the overall service life of the expander.

[0025] As one embodiment of the present invention; the guide cylinder 24 rotates on the disk 21; and uniformly arranged arc-shaped blades 26 are fixed below the vertical groove 25 on the inner ring of the guide cylinder 24; In this embodiment, the outer ring of the guide tube 24 has evenly arranged balls that rotate, and the balls rotate within the inner ring of the guide tube 13.

[0026] When the insulating oil expands in volume due to temperature changes and enters the guide cylinder 24 through the conduit 13, the oil flows along the inner ring of the guide cylinder 24 and continuously impacts the arc-shaped blades 26 fixed to the inner ring of the guide cylinder 24. The arc-shaped blades 26 generate a rotational torque under the impact force of the oil. Since the arc-shaped blades 26 are fixedly connected to the guide cylinder 24, and the guide cylinder 24 is rotatably fitted onto the disk 21, the rotation of the arc-shaped blades 26 will drive the entire guide cylinder 24 to rotate around the central axis of the disk 21. Furthermore, because the vertical slot 25 is open... Located on the outer ring of the guide cylinder 24, the vertical groove 25 of the outer ring rotates synchronously when the guide cylinder 24 rotates, realizing the dynamic relative motion between the vertical groove 25 and the oil. During the rotation of the guide cylinder 24, the balls evenly arranged on its outer ring will roll synchronously on the inner ring of the guide tube 13. Since the balls rotate and cooperate with the outer ring of the guide cylinder 24 and the inner ring of the guide tube 13 respectively, the sliding friction between the guide cylinder 24 and the guide tube 13 is converted into the rolling friction of the balls, thereby reducing the frictional resistance between the guide cylinder 24 and the guide tube 13 when the guide cylinder 24 rotates.

[0027] Specifically, through the rotational cooperation between the guide cylinder 24 and the disc 21, and the setting of the inner arc-shaped blades 26 of the guide cylinder 24, when the oil enters the guide cylinder 24, it can drive the guide cylinder 24 and the vertical groove 25 to rotate through the impact force. The rotating vertical groove 25 will make the insulating oil flow out evenly, avoiding the situation where the oil only flows out from the fixed position of the vertical groove 25 when the vertical groove 25 is fixed, which would cause the impact force of the oil on the corrugated core 12 to be concentrated in a local area. This effectively prevents the corrugated core 12 from being overloaded locally, reduces the local stress concentration of the corrugated core 12, further alleviates the fatigue damage caused by alternating loads, and extends the service life of the corrugated core 12. At the same time, the rotation of the guide cylinder 24 drives the vertical groove 25 to rotate, which can make the oil more evenly distributed in the cavity between the corrugated core 12, the guide cylinder 24, and the extension cylinder 2, avoiding the formation of air locks due to oil stagnation or uneven distribution, ensuring the smoothness of the expansion and contraction of the corrugated core 12, and improving the compensation stability of the expander.

[0028] As an embodiment of the present invention; four upright plates 3 are fixed to the top of the extension tube 2, and the inner circle of the upright plate 3 is arc-shaped, and the inner circle diameter of the upright plate 3 is the same as the inner circle diameter of the extension tube 2; a cross plate 31 is fixed on the four upright plates 3 together; The limiting disc 23 slides inside the extension cylinder 2; two threaded rods 32 are fixed to the top of the limiting disc 23; a threaded cylinder 33 is provided on the top of the two threaded rods 32; the threaded rods 32 are located inside the threaded cylinder 33 and are threadedly engaged with the threaded cylinder 33. The two threaded cylinders 33 pass through the cross plate 31 and are rotatably connected to the cross plate 31; the two threaded cylinders 33 are respectively located on both sides of the center of the cross plate 31.

[0029] In this embodiment, a first gear 34 rotates at the center of the cross plate 31, and the adding tube 22 passes through the inner ring of the first gear 34 and is slidably connected to the first gear 34; the adding tube 22 passes through the inside of the cross plate 31 and is slidably connected to the cross plate 31; the two threaded cylinders 33 have evenly arranged toothed grooves on the outer ring surface above the cross plate 31, and the toothed grooves mesh with the first gear 34.

[0030] By rotating the first gear 34 at the center of the cross plate 31, the rotation of the first gear 34 will synchronously drive the two threaded cylinders 33 with toothed grooves to rotate. Since the threaded cylinders 33 are rotatably connected to the cross plate 31, the threaded rod 32 is threadedly engaged with the threaded cylinders 33, and the limiting disc 23 is fixed at the bottom of the threaded rod 32 and slides inside the extension cylinder 2, when the threaded cylinder 33 rotates, the threaded rod 32 inside it cannot rotate synchronously with the threaded cylinder 33, but can only move up or down along the axial direction of the threaded cylinder 33. The up and down movement of the threaded rod 32 will synchronously drive the limiting disc 23 fixed at the bottom to slide up and down along the inner wall of the extension cylinder 2, thereby adjusting the position of the limiting disc 23 inside the extension cylinder 2. The limiting disc 23 is used to limit the upward movement distance of the disc 21. Therefore, the up and down movement of the limiting disc 23 will directly adjust the maximum sliding distance of the disc 21 inside the extension cylinder 2, thereby adjusting the effective volume inside the extension cylinder 2 that can be used to compensate for changes in the volume of insulating oil.

[0031] Specifically, by rotating the first gear 34, the two threaded cylinders 33 are simultaneously driven to rotate, which in turn pushes the threaded rod 32 to drive the limiting disc 23 to slide up and down. This flexibly adjusts the maximum sliding distance of the disc 21 within the extension cylinder 2, thereby adjusting the effective compensation volume of the extension cylinder 2 according to the temperature difference in different seasons and the temperature difference changes in the equipment operating environment. This ensures that the expansion volume of the insulating oil caused by the daily diurnal temperature difference and the peak and valley load fluctuations of the power grid can be completely controlled within the volume range of the extension cylinder 2. This avoids unnecessary tensioning or contraction of the corrugated core 12 due to daily temperature changes, thereby reducing the high-frequency reciprocating expansion and contraction of the corrugated core 12 from the source, reducing the cyclic alternating load borne by the corrugated sheet and welding parts, alleviating fatigue accumulation in stress concentration areas, inhibiting the initiation and propagation of microcracks, and effectively extending the overall service life of the corrugated core 12 and the expander.

[0032] As an embodiment of the present invention, a pressure sensor 35 is installed on the top of the protective shell 11; one of the threaded cylinders 33 is opposite to the pressure sensor 35.

[0033] In this embodiment, a second gear 36 is provided above the cross plate 31, and the second gear 36 and the two threaded cylinders 33 are triangularly distributed; the second gear 36 meshes with the first gear 34; the second gear 36 is driven by a motor 37, and the motor 37 is installed at the bottom of the cross plate 31.

[0034] In this embodiment, a sealing cylinder 38 is provided above the extension cylinder 2; the sealing cylinder 38 is fixed on four upright plates 3; the inner diameter of the sealing cylinder 38 is the same as the inner diameter of the extension cylinder 2. A limiting cylinder 4 is provided above the cross plate 31, and the limiting cylinder 4 is fixed on the protective shell 11; the outer diameter of the upright plate 3 and the sealing cylinder 38 is the same as the inner diameter of the limiting cylinder 4, and the upright plate 3 and the sealing cylinder 38 slide inside the limiting cylinder 4 in the initial state. The outer diameter of the extension tube 2 is the same as the inner diameter of the limiting tube 4. In the initial state, the top part of the extension tube 2 slides inside the limiting tube 4. The limiting cylinder 4 has evenly arranged liquid grooves 41 around its circumference; the sealing cylinder 38 is initially in contact with the liquid grooves 41 and seals the liquid grooves 41. The outer ring of the limiting cylinder 4 is provided with an annular chamber 5, and the annular chamber 5 is fixed on the flange 1; the opening of the annular chamber 5 is in contact with the limiting cylinder 4 and is opposite to the liquid tank 41. In this embodiment, the annular compartment 5 is provided with an annular block 51, and the top of the annular block 51 is a slope. A first electric actuator 52 is installed on the flange, and the extension rod of the first electric actuator 52 extends into the annular chamber 5 and is fixed on the annular block 51. Support blocks 53 are fixed on both sides of the outer ring of the extension cylinder 2; a second electric push rod 54 is installed on the flange 1 below the support block 53, and the second electric push rod 54 is not in contact with the support block 53 in the initial state. The disc 21 is provided with evenly arranged one-way valves.

[0035] In high-temperature summer conditions, if the ambient temperature is too high, the oil temperature will rise sharply, causing the insulating oil to continuously expand and enter the expander. This pushes the disc 21 to slide upward along the extension cylinder 2. The disc 21 will then drive the adding tube 22 to move upward along the limiting disc 23, the cross plate 31, and the protective shell 11 until the disc 21 moves upward and fits against the limiting disc 23. Subsequently, it will stretch the corrugated core 12. When the corrugated core 12 is stretched, it will drive the extension cylinder 2, which is fixed to its top, to move upward synchronously. When the extension cylinder 2 moves upward, it will drive the vertical plate 3 and the sealing cylinder 38, which are fixed to its top, to move upward together. After moving upward a certain distance, the sealing cylinder 38 will disengage from the contact state with the liquid groove 41 on the outer ring of the limiting cylinder 4 and move to a position above the liquid groove 41. At this time, the disc 21 and the limiting disc 23 are still located inside the extension cylinder 2. As the extension cylinder 2 continues to move upward, one of the threads The screw cylinder 33 will move upward synchronously and act on the pressure sensor 35. If the high temperature in summer continues and the oil temperature remains high, the insulating oil will continue to expand, causing the screw cylinder 33 to apply pressure to the pressure sensor 35 for a long time. The pressure sensor 35 will send a signal to control the motor 37 to start. The motor 37 drives the second gear 36 to rotate. The rotation of the second gear 36 will drive the first gear 34 to rotate synchronously. After the first gear 34 rotates, it will drive the two screw cylinders 33 to rotate synchronously. When the screw cylinder 33 rotates, the threaded rod 32 meshing inside it will gradually be drawn into the screw cylinder 33. The contraction of the threaded rod 32 will drive the bottom fixed limiting disk 23 to move upward and gradually move into the sealing cylinder 38. At the same time, under the continuous pressure of the insulating oil, the disc 21 will drive the guide cylinder 24 connected to it to move upward synchronously until the guide cylinder 24 is in contact with the limiting disk 23. At this time, the disc 21 and the limiting disc 23 no longer obstruct the top of the extension cylinder 2. The inside of the extension cylinder 2 is connected to the liquid tank 41 of the limiting cylinder 4. The insulating oil will enter the annular chamber 5 through the evenly arranged liquid tanks 41 on the circumference of the limiting cylinder 4. At the same time, the pressure sensor 35 sends a signal to control the first electric actuator 52 to start. The first electric actuator 52 drives the annular block 51 to move down. After the annular block 51 moves down, sufficient storage space is formed in the annular chamber 5. The insulating oil that has entered the liquid tank 41 can flow smoothly into the annular chamber 5 for temporary storage, avoiding the continuous expansion of the insulating oil due to excessively high summer temperatures, which would cause the corrugated core 12 to be in a state of long-term heat. In a fully stretched state, the corrugated core 12 is prevented from cracking, bulging, or other failures due to long-term excessive tensile stress. When the external temperature and oil temperature drop, the volume of the insulating oil shrinks, and the corrugated core 12 gradually shrinks under its own elastic force, thereby driving the extension cylinder 2, the vertical plate 3, and the sealing cylinder 38 to move down synchronously. During the downward movement, the sealing cylinder 38 will gradually re-fit with the liquid tank 41 of the limiting cylinder 4, sealing the liquid tank 41 and preventing the insulating oil stored in the annular chamber 5 from flowing back. Subsequently, the staff can check the oil level in the tank according to the oil level in the tank to ensure the normal operation of the equipment.

[0036] In low-temperature winter conditions, the ambient temperature is too low, causing a significant drop in oil temperature and shrinkage of the insulating oil volume. The insulating oil in the corrugated core 12 and the extension cylinder 2 will continuously flow back into the oil tank. When the corrugated core 12 is fully contracted, if the insulating oil continues to flow into the oil tank, the equipment control system will send a signal to activate the second electric actuator 54. The extension rod of the second electric actuator 54 will extend, pushing the support blocks 53 fixed on both sides of the extension cylinder 2 upward. The upward movement of the support blocks 53 will cause the extension cylinder 2 to move upward synchronously, stretching the corrugated core 12 in the fully contracted state. At the same time, the upward movement of the extension cylinder 2 will cause the four vertical plates 3, the sealing cylinder 38, and the threaded cylinder 33 to move upward together, and control the limiting plate 23 to move above the liquid tank 41 of the limiting cylinder 4, and the sealing cylinder 38 to separate from the liquid tank 41. The control system then controls the first electric actuator 52. Upon startup, the first electric actuator 52 moves the annular block 51 inside the annular chamber 5 upwards. The inclined surface at the top of the annular block 51 pushes the insulating oil stored inside the annular chamber 5, causing the insulating oil to be pushed into the space below the limiting disc 23 through the liquid trough 41 around the limiting cylinder 4. Since the disc 21 is equipped with evenly distributed one-way valves, which allow the insulating oil to flow from below the limiting disc 23 to below the disc 21, the insulating oil entering below the limiting disc 23 will flow to the space below the disc 21 through the one-way valves, replenishing the insulating oil in the extension cylinder 2 and the corrugated core 12 until the insulating oil stops flowing back and the corrugated core 12 stops contracting. At this time, the second electric actuator 54 contracts and resets, and the extension cylinder 2 returns to its normal position under the elastic action of the corrugated core 12. The sealing cylinder 38 re-fits the liquid trough 41, completing the replenishment of insulating oil and preventing the corrugated core 12 from being in a fully contracted state for a long time.

[0037] When a short circuit occurs in the oil tank, the electric arc generated by the short circuit will instantly cause the temperature of the insulating oil to rise sharply and its volume to expand rapidly, generating a momentary high voltage. This high voltage will push the extension cylinder 2, the vertical plate 3, and the threaded cylinder 33 to move upward rapidly. One of the threaded cylinders 33, which is opposite to the pressure sensor 35, will quickly act on the pressure sensor 35. After detecting the momentary high voltage signal, the pressure sensor 35 will immediately send a signal to control the motor 37 to start. The motor 37 drives the second gear 36 to rotate, and the second gear 36 drives the first gear 34 to rotate. The two threaded cylinders 33 rotate synchronously, causing the threaded rod 32 to retract and the limiting disc 23 to move quickly upward to the position above the liquid tank 41 of the limiting cylinder 4. At this time, the sealing cylinder 38 moves upward with the vertical plate 3 and separates from the liquid tank 41, and the liquid tank 41 is unobstructed. The high-voltage insulating oil generated by the short circuit will quickly enter the annular chamber 5 through the liquid tank 41 to achieve instantaneous pressure relief, avoid the high voltage from acting directly on the corrugated core 12, and prevent the corrugated core 12 from being damaged, cracked, or leaking due to exceeding its pressure bearing capacity, thus buying time for equipment failure handling.

[0038] In the description of this invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the appendix. Figure 1 The orientations or positional relationships shown are for the convenience of describing the present invention and simplifying the description only, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description and should not be construed as indicating or implying relative importance.

[0039] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A corrugated expander, comprising a flange (1); a protective shell (11) is mounted on the flange (1); a corrugated core (12) is mounted on the flange; and a guide tube (13) is mounted at the bottom of the flange (1); Its features are, The corrugated core (12) is fixed to the top of the extension cylinder (2), and the corrugated core (12) is connected to the extension cylinder (2); a disc (21) slides inside the extension cylinder (2); An adding tube (22) is fixed in the middle of the disc (21), and the bottom of the adding tube (22) is connected to the bottom space of the disc (21), and the top extends to the top of the protective shell (11) and is slidably connected to the protective shell (11); an oil injection valve is installed on the top of the adding tube (22); The disc (21) is provided with a limiting disc (23) at its top; the limiting disc (23) is located inside the extension tube (2); the adding tube (22) passes through the limiting disc (23) and is slidably connected to the limiting disc (23); The bottom of the disk (21) is provided with a guide tube (24), and the guide tube (24) passes through the corrugated core (12) and extends into the guide tube (13); The guide tube (24) has evenly arranged vertical grooves (25) on its outer ring, and the vertical grooves (25) do not penetrate the top and bottom of the guide tube (24).

2. The corrugated expander according to claim 1, characterized in that: The guide tube (24) rotates on the disk (21); below the vertical groove (25) are uniformly arranged arc-shaped blades (26) fixed in the inner circle of the guide tube (24).

3. The corrugated expander according to claim 2, characterized in that: The outer ring of the guide tube (24) has evenly arranged balls rotating, and the balls rotate within the inner ring of the guide tube (13).

4. The corrugated expander according to claim 1, characterized in that: The top of the extension tube (2) is fixed with four vertical plates (3), and the inner circle of the vertical plate (3) is arc-shaped, and the inner circle diameter of the vertical plate (3) is the same as the inner circle diameter of the extension tube (2); A cross plate (31) is fixed to all four of the upright plates (3); The limiting disc (23) slides inside the extension cylinder (2); two threaded rods (32) are fixed to the top of the limiting disc (23); threaded cylinders (33) are provided on the top of the two threaded rods (32); The threaded rod (32) is located inside the threaded cylinder (33) and is threadedly engaged with the threaded cylinder (33); The two threaded cylinders (33) pass through the cross plate (31) and are rotatably connected to the cross plate (31); the two threaded cylinders (33) are located on both sides of the center of the cross plate (31).

5. The corrugated expander according to claim 4, characterized in that: The cross plate (31) has a first gear (34) rotating at its center. The adding tube (22) passes through the inner ring of the first gear (34) and is slidably connected to the first gear (34); the adding tube (22) passes through the cross plate (31) and is slidably connected to the cross plate (31); The two threaded cylinders (33) have evenly arranged toothed grooves on the outer ring surface above the cross plate (31), and the toothed grooves mesh with the first gear (34).

6. The corrugated expander according to claim 5, characterized in that: A pressure sensor (35) is installed on the top of the protective shell (11); One of the threaded cylinders (33) is opposite the pressure sensor (35).

7. The corrugated expander according to claim 6, characterized in that: A second gear (36) is provided above the cross plate (31), and the second gear (36) and the two threaded cylinders (33) are triangularly distributed; The second gear (36) meshes with the first gear (34); the second gear (36) is driven by a motor (37), and the motor (37) is installed at the bottom of the cross plate (31).

8. The corrugated expander according to claim 7, characterized in that: A sealing cylinder (38) is provided above the extension cylinder (2); The sealing cylinder (38) is fixed on four upright plates (3); the inner diameter of the sealing cylinder (38) is the same as the inner diameter of the extension cylinder (2); A limiting cylinder (4) is provided above the cross plate (31), and the limiting cylinder (4) is fixed on the protective shell (11); the outer diameter of the upright plate (3) and the sealing cylinder (38) is the same as the inner diameter of the limiting cylinder (4), and the upright plate (3) and the sealing cylinder (38) slide inside the limiting cylinder (4) in the initial state; The outer diameter of the extension tube (2) is the same as the inner diameter of the limiting tube (4). In the initial state, the top part of the extension tube (2) slides inside the limiting tube (4). The limiting cylinder (4) has uniformly arranged liquid troughs (41) around its circumference; the sealing cylinder (38) is initially in contact with the liquid troughs (41) and seals the liquid troughs (41); The outer ring of the limiting cylinder (4) is provided with an annular chamber (5), and the annular chamber (5) is fixed on the flange (1); the opening of the annular chamber (5) is in contact with the limiting cylinder (4) and is opposite to the liquid tank (41).

9. The corrugated expander according to claim 8, characterized in that: The annular compartment (5) is provided with an annular block (51), and the top of the annular block (51) is a slope; A first electric actuator (52) is installed on the flange, and the extension rod of the first electric actuator (52) extends into the annular chamber (5) and is fixed on the annular block (51); The extension tube (2) has support blocks (53) fixed on both sides of its outer ring; a second electric push rod (54) is installed on the flange (1) below the support block (53), and the second electric push rod (54) is not in contact with the support block (53) in its initial state; The disc (21) is provided with evenly arranged one-way valves.

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