Drop-out fuse and use method thereof

Abstract

The invention discloses a drop-out fuse and a use method thereof, and relates to the technical field of fuses, the drop-out fuse comprises an insulator, a fusion tube is arranged on one side of the insulator, and an arc extinguishing tube is coaxially inserted in the fusion tube; a melt is coaxially inserted into the arc extinguishing tube; the two ends of the fusion tube are provided with moisture-proof sealing mechanisms. The moisture-proof sealing mechanism is arranged, the sealing check ring and the breathable moisture-proof film are matched to form first-stage sealing, the sealing rubber ring and the sealing check ring abut against each other to form second-stage sealing, the double-sealing structure prevents outdoor water vapor, dust and other impurities from entering the arc extinguishing tube from the source, and the condensation probability of water vapor between a melt and the inner wall of the arc extinguishing tube is reduced; meanwhile, a vent groove in the sealing check ring and a first through hole in the positioning clamping seat provide an exclusive discharge channel for high-pressure arc-extinguishing gas in the arc-extinguishing tube, the breathable moisture-proof film has the breathable and waterproof characteristics, it is guaranteed that the high-pressure gas can be smoothly discharged out of the fusion tube when the fuse body is fused, and the phenomenon that the inner air pressure of the fusion tube is too high to cause bulging cracks is avoided.

Description

Technical Field

[0001] This invention relates to the field of fuse technology, and in particular to a drop-out fuse and its usage method. Background Technology

[0002] Drop-out fuses are widely used short-circuit and overload protection devices in outdoor high-voltage power distribution lines. They are mainly used to protect outdoor power distribution lines, distribution transformers, and other equipment. Their core structure includes a fuse tube, fuse element, arc-extinguishing tube, upper moving contact, lower moving contact, and insulators. During operation, the fuse element is connected in series in the circuit. When a short circuit or overload fault occurs, the fuse element melts due to heat. The fuse tube, under its own weight and spring force, falls around the lower pivot, forming a clear physical break and disconnecting the circuit. Simultaneously, the arc-extinguishing tube quickly extinguishes the arc generated when the fuse element melts, preventing the fault from spreading. Drop-out fuses occupy an important position in outdoor power distribution systems due to their advantages such as simple structure, convenient operation, no need for external power supply, and low cost. However, existing drop-out fuses still have the following drawbacks in use: Because there is a tiny gap between the molten material inside the fuse tube and the inner wall of the arc-suppression tube, moisture in the air can enter this gap and condense into ice, forming an "ice wedge" structure. This ice wedge exerts continuous mechanical pressure on the molten material. On the one hand, this may cause the molten material to break due to mechanical stress under normal fault conditions, resulting in false tripping of the power distribution line and affecting the stability of the power supply. On the other hand, when a line fault occurs and the molten material melts, the ice wedge will prevent the remaining fragment of the molten material from detaching from the inner wall of the arc-suppression tube, preventing the fuse tube from falling smoothly. This will cause the fuse to lose its circuit protection function, potentially leading to serious consequences such as the expansion of the line fault and equipment damage. Summary of the Invention

[0003] The purpose of this application is to provide a drop-out fuse and its usage method, which can effectively solve the problems mentioned in the background art.

[0004] To achieve the above objectives, this application provides the following technical solution: a drop-out fuse, comprising an insulator, with an upper support and a lower support respectively provided at both ends of the insulator, a fuse tube provided on one side of the insulator, one end of the fuse tube connected to the upper support, and the other end of the fuse tube hinged to the lower support, an arc-extinguishing tube coaxially inserted inside the fuse tube; a fusible element coaxially inserted inside the arc-extinguishing tube; and a moisture-proof sealing mechanism provided at both ends of the fuse tube; the moisture-proof sealing mechanism includes: a sealing retaining ring, a breathable moisture-proof membrane, a positioning bracket, a moving contact, and a sealing rubber ring; wherein, the sealing retaining ring is disposed between the fuse tube and the arc-extinguishing tube, and the inner ring of the sealing retaining ring is connected to the arc-extinguishing tube. A gap is formed between the tubes; the breathable and moisture-proof membrane is placed over the end of the arc-extinguishing tube, and the sealing ring is connected to the breathable and moisture-proof membrane; the gas in the arc-extinguishing tube is allowed to pass through the breathable and moisture-proof membrane and then pass through the gap to enter between the melting tube and the arc-extinguishing tube; the positioning bracket is fixed to the melting tube; the moving contact is coaxially inserted into the positioning bracket; the sealing ring is coaxially sleeved on the moving contact, and the sealing ring abuts against the sealing ring; a venting groove is opened on the sealing ring, and a first through hole is opened on the positioning bracket; the gas between the melting tube and the arc-extinguishing tube is allowed to pass through the venting groove and enter the gap between the positioning bracket and the moving contact, and then be discharged through the first through hole.

[0005] Preferably, the arc-extinguishing tube is equipped with a low-temperature adaptive heating mechanism; when the ambient temperature is below a certain value, heating is allowed through the low-temperature adaptive heating mechanism; when the ambient temperature is above a certain value, the resistance value increases sharply, thereby causing the circuit to be in a cut-off state, so as to achieve adaptive control of the heating temperature.

[0006] Preferably, the low-temperature adaptive heating mechanism includes an insulated thermally conductive bracket, a miniature heating wire, and a low-temperature thermistor; the insulated thermally conductive bracket is fixed inside the arc-extinguishing tube, and the miniature heating wire and the low-temperature thermistor are both installed on the insulated thermally conductive bracket, and the miniature heating wire and the low-temperature thermistor are electrically connected.

[0007] Preferably, the insulating heat-conducting bracket has multiple second through holes so that the interior of the arc-extinguishing tube is in a conductive state.

[0008] Preferably, thermally conductive silicone is applied between the insulating thermally conductive bracket and the inner wall of the arc-extinguishing tube.

[0009] Preferably, the micro heating wire is arranged in a spiral shape inside the arc-extinguishing tube, and the length of the spiral structure is adapted to the length of the arc-extinguishing tube.

[0010] Preferably, both ends of the melting tube are provided with positioning mechanisms, which are used to position and buffer the mechanical extrusion force of the ice wedge on the melt.

[0011] Preferably, the positioning mechanism includes a buffer spring, an insulating sleeve, and a conductive sheet; one end of the buffer spring is connected to the moving contact, the insulating sleeve is fitted onto the end of the molten material, and the other end of the buffer spring is connected to the end of the molten material through the conductive sheet; allowing a circuit to be formed between the molten material, the conductive sheet, the buffer spring, and the moving contact.

[0012] Preferably, the buffer spring is fitted with an insulating telescopic sleeve, the breathable and moisture-proof membrane has a third through hole, one end of the insulating telescopic sleeve passes through the third through hole and is connected to the moving contact, and the other end of the insulating telescopic sleeve is connected to the insulating isolation sleeve; the insulating telescopic sleeve and the third through hole are sealed together to prevent water vapor from flowing through the gap between the insulating telescopic sleeve and the third through hole.

[0013] A method for using a drop-out fuse, employing the aforementioned drop-out fuse; specifically including the following steps: Step 1, Primary Sealing: By combining the sealing ring with the breathable and moisture-proof membrane, the tiny gap between the inner wall of the molten tube and the outer wall of the arc-extinguishing tube is directly filled, becoming the first barrier for outdoor moisture to enter the interior of the arc-extinguishing tube, blocking most moisture, dust and other impurities from entering. Step 2, Secondary Sealing: The tiny gaps between the moving contact rod and the sealing ring and the breathable moisture-proof membrane are filled by the sealing rubber ring, forming a seal at the location where the moving contact passes through, thus forming a second sealing barrier. At the same time, the elasticity of the sealing rubber ring is used to buffer the impact of outdoor wind vibration on the sealing structure. Step 3, Breathable and Moisture-proof: By fixing the breathable and moisture-proof membrane between the sealing ring and the end face of the arc-extinguishing tube port, the arc-extinguishing tube port is fully covered. Its microporous characteristics of being breathable but not water-permeable can block water vapor while allowing gas to pass through; and when the fuse melts due to a circuit fault, a large amount of arc-extinguishing gas generated inside the arc-extinguishing tube can be smoothly discharged from the fuse tube through the micropores.

[0014] In summary, the technical effects and advantages of this invention are as follows: 1. This invention employs a moisture-proof sealing mechanism. A sealing ring and a breathable moisture-proof membrane work together to form a primary seal, filling the gap between the molten tube and the arc-extinguishing tube. A sealing rubber ring, in contact with the sealing ring, forms a secondary seal, filling the gap between the moving contact and the sealing ring. This dual-seal structure prevents outdoor moisture, dust, and other impurities from entering the arc-extinguishing tube, reducing the probability of condensation between the molten material and the inner wall of the arc-extinguishing tube. Simultaneously, the venting groove on the sealing ring and the first through hole on the positioning bracket provide a dedicated outlet for the high-pressure arc-extinguishing gas inside the arc-extinguishing tube. The breathable moisture-proof membrane is both breathable and waterproof, ensuring that high-pressure gas can be smoothly discharged from the molten tube when it melts, preventing excessive pressure inside the molten tube from causing cracking. Furthermore, all components of the moisture-proof sealing mechanism use flexible sealing or gap-fit ​​designs, ensuring they do not interfere with the normal drop action of the molten tube. This design combines the core functions of moisture-proof sealing, arc extinguishing and venting of the fuse, and fault diagnosis.

[0015] 2. This invention utilizes a low-temperature adaptive heating mechanism that employs a low-temperature thermistor to sense the internal temperature of the arc-extinguishing tube in real time. When the temperature falls below a set value, the circuit is automatically activated, causing the miniature heating wire to heat up. The heat is rapidly and evenly transferred to the inside of the arc-extinguishing tube via an insulated thermally conductive bracket and thermally conductive silicone, raising the temperature of the gaps around the melt and melting tiny ice particles. When the temperature exceeds the set value, the resistance of the low-temperature thermistor increases sharply, causing the circuit to shut off and the miniature heating wire to stop heating. This achieves adaptive control of the internal temperature of the arc-extinguishing tube. The mechanism is powered by the weak induced current in the circuit containing the melt, eliminating the need for an additional power source. Furthermore, its modular integrated design makes installation and maintenance convenient. Together with the moisture-proof sealing mechanism, it provides synergistic protection, further eliminating the possibility of ice wedge formation due to temperature conditions, making it suitable for unattended outdoor power distribution scenarios.

[0016] 3. This invention, through the setting of a positioning mechanism, utilizes the cooperative structure of a buffer spring, an insulating sleeve, and a conductive sheet to precisely position the molten material at the axial center and circumferential center of the arc-extinguishing tube. This ensures that the gap between the molten material and the inner wall of the arc-extinguishing tube remains uniform throughout the circumference, avoiding the problem of excessively small local gaps and water vapor accumulation and icing caused by molten material displacement. When the ice wedge exerts mechanical pressure on the molten material, the buffer spring will elastically contract, converting the mechanical stress into elastic potential energy, effectively buffering the pressure and preventing the molten material from non-fault fracture due to stress concentration. At the same time, when the molten material melts, the buffer spring releases elastic potential energy to generate axial thrust, pushing the melted fragment of the molten material away from the inner wall of the arc-extinguishing tube. This prevents the ice wedge from obstructing the fragment's detachment, thus ensuring that the molten tube can normally disconnect the circuit in the event of a fuse failure. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the overall three-dimensional structure of the present invention; Figure 2 This is a three-dimensional enlarged structural schematic diagram of the fusion tube of the present invention; Figure 3 This is a partially cross-sectional, three-dimensional enlarged structural diagram of the moisture-proof sealing mechanism of the present invention; Figure 4 This is a partially cross-sectional, three-dimensional enlarged structural diagram of the fusion tube and arc-extinguishing tube of the present invention; Figure 5 For the present invention Figure 4 Enlarged structural diagram of region A in the middle; Figure 6 This is a three-dimensional enlarged structural schematic diagram of the sealing ring of the present invention; Figure 7 This is a partially cross-sectional, enlarged three-dimensional structural diagram of the positioning mechanism of the present invention; Figure 8 This is a front view enlarged sectional view of the moisture-proof sealing mechanism and positioning mechanism of the present invention; Figure 9 This is a three-dimensional enlarged structural schematic diagram of the low-temperature adaptive heating mechanism of the present invention; Figure 10 This is a flowchart of the method of the present invention.

[0019] In the diagram: 1. Insulator; 2. Upper support; 3. Lower support; 4. Fusible tube; 5. Arc extinguishing tube; 6. Moisture-proof sealing mechanism; 61. Sealing ring; 62. Breathable and moisture-proof membrane; 63. Positioning bracket; 64. Moving contact; 65. Sealing ring; 66. Ventilation groove; 67. Spacing; 68. First through hole; 7. Low-temperature adaptive heating mechanism; 71. Insulating heat-conducting support; 72. Second through hole; 73. Miniature heating wire; 74. Low-temperature thermistor; 8. Positioning mechanism; 81. Buffer spring; 82. Insulating telescopic sleeve; 83. Insulating isolation sleeve; 84. Conductive sheet; 9. Fusible element. Detailed Implementation

[0020] 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.

[0021] Example 1: Please refer to Figures 1-3 and Figures 4-5The diagram shows a drop-out fuse, comprising an insulator 1, with an upper support 2 and a lower support 3 at both ends of the insulator 1. A fuse tube 4 is provided on one side of the insulator 1, with one end of the fuse tube 4 connected to the insulator 1 and the other end of the fuse tube 4 hinged to the lower support 3. An arc-extinguishing tube 5 is coaxially inserted into the fuse tube 4; a fusible element 9 is coaxially inserted into the arc-extinguishing tube 5; both ends of the fuse tube 4 are provided with a moisture-proof sealing mechanism 6; the moisture-proof sealing mechanism 6 includes: a sealing retaining ring 61, a breathable moisture-proof membrane 62, a positioning bracket 63, a moving contact 64, and a sealing rubber ring 65; wherein, the sealing retaining ring 61 is disposed between the fuse tube 4 and the arc-extinguishing tube 5, and a gap 67 is formed between the inner ring of the sealing retaining ring 61 and the arc-extinguishing tube 5; the breathable moisture-proof membrane 62 covers... A sealing ring 61 is located at the end of the arc-extinguishing tube 5 and connected to a breathable and moisture-proof membrane 62. This allows gas in the arc-extinguishing tube 5 to pass through the breathable and moisture-proof membrane 62 and then through the membrane 62 again, passing through a gap 67 to enter the space between the molten tube 4 and the arc-extinguishing tube 5. A positioning bracket 63 is fixed to the molten tube 4. A moving contact 64 is coaxially inserted into the positioning bracket 63. A sealing ring 65 is coaxially sleeved on the moving contact 64, and the sealing ring 65 abuts against the sealing ring 61. A venting groove 66 is provided on the sealing ring 61, and a first through hole 68 is provided on the positioning bracket 63. This allows gas between the molten tube 4 and the arc-extinguishing tube 5 to pass through the venting groove 66 and enter the gap between the positioning bracket 63 and the moving contact 64, and then exit through the first through hole 68.

[0022] It should be noted that when the melt 9 is normally conducting, the moisture-proof sealing mechanism 6 seals the gap between the melt tube 4 and the arc-extinguishing tube 5, preventing outdoor moisture from entering the interior of the arc-extinguishing tube 5. When the circuit fails and the melt 9 melts, the high-pressure arc-extinguishing gas generated inside the arc-extinguishing tube 5 is first discharged to the outside of the arc-extinguishing tube 5 through the micropores of the breathable moisture-proof membrane 62. After the gas enters the gap between the melt tube 4 and the arc-extinguishing tube 5, it passes through the venting groove 66 on the sealing ring 61, enters the gap between the positioning card seat 63 and the moving contact 64, and is finally discharged to the outdoor atmosphere through the first through hole 68 on the positioning card seat 63, completing the high-pressure exhaust and pressure relief.

[0023] By setting moisture-proof sealing mechanisms 6 at both ends of the molten tube 4, the primary sealing of the gap between the molten tube 4 and the arc-extinguishing tube 5 is achieved through the cooperation of the sealing ring 61 and the breathable moisture-proof membrane 62. The secondary sealing is achieved by filling the gap between the moving contact 64 and the sealing ring 61 through the sealing ring 65. The double sealing structure blocks outdoor moisture from entering the arc-extinguishing tube 5 from the source, reducing the probability of ice wedge formation between the molten body 9 and the inner wall of the arc-extinguishing tube 5. At the same time, the ventilation groove 66 on the sealing ring 61 cooperates with the first through hole 68 on the positioning bracket 63 to provide a dedicated discharge channel for the high-pressure arc-extinguishing gas, ensuring that the high-pressure gas in the arc-extinguishing tube 5 can be discharged smoothly when the molten body 9 melts, avoiding excessive gas pressure inside the molten tube 4 that could cause cracking. Moreover, all components of the moisture-proof sealing mechanism 6 are designed with flexible sealing or gap fit, which will not interfere with the falling action of the molten tube 4, thus taking into account both the moisture-proof sealing and the core arc-extinguishing and venting functions of the fuse.

[0024] See Figure 4 The arc-extinguishing tube 5 is equipped with a low-temperature adaptive heating mechanism 7. When the ambient temperature is below a certain value, heating is allowed through the low-temperature adaptive heating mechanism 7. When the ambient temperature is above a certain value, the resistance value increases sharply, thereby causing the circuit to be in a cut-off state, so as to achieve adaptive control of the heating temperature.

[0025] It should be noted that the low-temperature adaptive heating mechanism 7 is powered by the weak induced current in the circuit containing the melt 9. When the outdoor ambient temperature drops to the set value, the circuit is automatically turned on and the heating starts. The heat is transferred to the inside of the arc-extinguishing tube 5, raising the temperature of the gap between the melt 9 and the inner wall of the arc-extinguishing tube 5, melting the tiny ice particles that have condensed in the gap. When the ambient temperature rises to the set value, the resistance of the low-temperature adaptive heating mechanism 7 increases sharply, the circuit is in the cut-off state, and the low-temperature adaptive heating mechanism 7 stops heating. This achieves adaptive control of the heating temperature inside the arc-extinguishing tube 5, always keeping the temperature around the melt 9 in a range where it is not easy to freeze.

[0026] By setting up a low-temperature adaptive heating mechanism 7, the internal temperature of the arc-extinguishing tube 5 is actively regulated, eliminating the possibility of ice wedge formation from the temperature conditions. It forms a synergistic protection with the moisture-proof sealing mechanism 6, further reducing the probability of ice wedge formation. Moreover, the low-temperature adaptive heating mechanism 7 adopts an adaptive temperature control design, requiring no manual intervention and is suitable for outdoor unattended power distribution scenarios. At the same time, the mechanism uses the induced current of the fuse's own circuit for power supply, eliminating the need for an additional power source and reducing the cost of using and maintaining the equipment.

[0027] See Figure 4 and Figure 9The low-temperature adaptive heating mechanism 7 includes an insulating heat-conducting bracket 71, a miniature heating wire 73, and a low-temperature thermistor 74. The insulating heat-conducting bracket 71 is fixed inside the arc-extinguishing tube 5. The miniature heating wire 73 and the low-temperature thermistor 74 are both installed on the insulating heat-conducting bracket 71. The miniature heating wire 73 and the low-temperature thermistor 74 are connected by electrical control.

[0028] It should be noted that the low-temperature thermistor 74 senses the internal temperature of the arc-extinguishing tube 5 in real time. When the temperature is lower than the set value, the resistance of the low-temperature thermistor 74 decreases, the circuit is turned on, the miniature heating wire 73 is energized and generates heat, and the heat is transferred to the inside of the arc-extinguishing tube 5 through the insulating heat-conducting bracket 71. When the temperature is higher than the set value, the resistance of the low-temperature thermistor 74 increases sharply, the circuit is turned off, and the miniature heating wire 73 stops heating.

[0029] The miniature heating wire 73 and the low-temperature thermistor 74 are integrated onto the insulating heat-conducting bracket 71, realizing a modular design of the low-temperature adaptive heating mechanism 7, which is convenient for installation and maintenance. The insulating heat-conducting bracket 71 can not only fix and protect the miniature heating wire 73 and the low-temperature thermistor 74, but also transfer the heat generated by the miniature heating wire 73 to the inside of the arc-extinguishing tube 5, improving heating efficiency. At the same time, the insulation characteristics of the insulating heat-conducting bracket 71 can prevent short circuits between the heating mechanism and the melt 9 and the arc-extinguishing tube 5, improving the safety of equipment operation and achieving a dual anti-icing wedge effect of water vapor barrier and temperature control.

[0030] See Figure 4 and Figure 9 Multiple second through holes 72 are provided on the insulating heat-conducting bracket 71 so that the interior of the arc-extinguishing tube 5 is in a conductive state.

[0031] It should be noted that when the melt 9 melts, the high-pressure arc-extinguishing gas generated inside the arc-extinguishing tube 5 can flow freely inside the arc-extinguishing tube 5 through the second through hole 72, making the entire interior of the arc-extinguishing tube 5 conductive. This ensures that the high-pressure gas can quickly converge to both ends of the arc-extinguishing tube 5 and be discharged. At the same time, when heat is transferred inside the arc-extinguishing tube 5, thermal convection can be achieved through the second through hole 72, improving the uniformity of the internal temperature of the arc-extinguishing tube 5.

[0032] See Figure 4 and Figure 9Thermally conductive silicone is applied between the insulating thermally conductive bracket 71 and the inner wall of the arc-extinguishing tube 5. It should be noted that the thermally conductive silicone adheres tightly to the inner wall of the insulating thermally conductive bracket 71 and the arc-extinguishing tube 5. The heat generated by the micro heating wire 73 is transferred through the insulating thermally conductive bracket 71 to the thermally conductive silicone, and then from the thermally conductive silicone to the inner wall of the arc-extinguishing tube 5, ultimately diffusing into the gap between the melt 9 and the inner wall of the arc-extinguishing tube 5.

[0033] Applying thermally conductive silicone between the insulating thermally conductive bracket 71 and the inner wall of the arc-extinguishing tube 5 can reduce the contact thermal resistance between the two, improve the heat transfer efficiency, and allow the heat generated by the micro heating wire 73 to be transferred to the inside of the arc-extinguishing tube 5 more quickly and evenly, shorten the melting time, and improve the response speed of the low-temperature adaptive heating mechanism 7. At the same time, the thermally conductive silicone can also play an auxiliary role in fixing the insulating thermally conductive bracket 71, enhancing its installation stability inside the arc-extinguishing tube 5, and preventing the low-temperature adaptive heating mechanism 7 from shifting due to outdoor vibration.

[0034] See Figure 4 and Figure 9 The micro heating wire 73 is spirally arranged inside the arc-extinguishing tube 5, and the length of the spiral structure is adapted to the length of the arc-extinguishing tube 5. It should be noted that the spiral micro heating wire 73 extends along the axial direction of the arc-extinguishing tube 5, and its coverage area matches the arrangement range of the melt 9 inside the arc-extinguishing tube 5. Setting the micro heating wire 73 as a spiral structure adapted to the length of the arc-extinguishing tube 5 can increase the heating area of ​​the micro heating wire 73, making the heat distribution inside the arc-extinguishing tube 5 more uniform, ensuring that all sections of the melt 9 can be effectively heated, avoiding the formation of ice wedges due to inadequate local heating. At the same time, the spiral arrangement can make full use of the space inside the arc-extinguishing tube 5, without affecting the normal installation of the melt 9 and the flow of high-pressure gas, thus eliminating the conditions for ice wedge formation from both spatial and temperature perspectives.

[0035] See Figures 7-8 Both ends of the melting tube 4 are equipped with positioning mechanisms 8, which are used to position and buffer the mechanical extrusion force of the ice wedge on the melt 9.

[0036] It should be noted that the positioning mechanism 8 precisely positions the melt 9 at the axial center and circumferential center of the arc-extinguishing tube 5, making the circumferential gap between the melt 9 and the inner wall of the arc-extinguishing tube 5 uniform. When a small amount of ice wedges form between the melt 9 and the inner wall of the arc-extinguishing tube 5 and exert mechanical extrusion force on the melt 9, the positioning mechanism 8 can buffer the extrusion force, absorb the mechanical stress generated by the ice wedges, and prevent the melt 9 from undergoing non-fault fracture due to stress concentration.

[0037] Positioning mechanisms 8 are installed at both ends of the fuse tube 4. On the one hand, they can achieve precise center positioning of the melt 9 within the arc extinguishing tube 5, avoiding the problem of excessively small local gaps and water vapor accumulation and icing caused by the displacement of the melt 9, thus structurally reducing the probability of ice wedge formation. On the other hand, they can effectively buffer the mechanical extrusion force generated by the ice wedge, preventing the melt 9 from undergoing non-fault fracture due to mechanical stress, and preventing the fuse from tripping falsely due to the ice wedge.

[0038] See Figures 7-8 The positioning mechanism 8 includes a buffer spring 81, an insulating sleeve 83, and a conductive sheet 84; one end of the buffer spring 81 is connected to the moving contact 64, the insulating sleeve 83 is sleeved on the end of the melt 9, and the other end of the buffer spring 81 is connected to the end of the melt 9 through the conductive sheet 84; allowing a circuit to be formed between the melt 9, the conductive sheet 84, the buffer spring 81, and the moving contact 64.

[0039] It should be noted that the current is transmitted from the external circuit to the buffer spring 81 via the moving contact 64, and then to the molten element 9 via the conductive sheet 84, thus realizing the conduction of the circuit. When the ice wedge exerts mechanical squeezing force on the molten element 9, the molten element 9 transmits the squeezing force to the insulating sleeve 83. The insulating sleeve 83 transmits the force evenly to the buffer spring 81. The buffer spring 81 undergoes elastic contraction, converting the mechanical squeezing force into elastic potential energy, thereby buffering the squeezing force. When the molten element 9 melts due to a fault, the buffer spring 81 releases the elastic potential energy, generating an axial thrust, which pushes the melted remnant of the molten element 9 towards both ends of the arc-extinguishing tube 5, causing the remnant to detach from the inner wall of the arc-extinguishing tube 5.

[0040] The conductive sheet 84 enables the conductive connection between the buffer spring 81 and the melt 9, allowing the positioning mechanism 8 to not only perform the positioning and buffering functions of the melt 9, but also to form a complete conductive circuit as a conductive carrier. This eliminates the need for additional conductive components, simplifying the internal structure of the melt tube 4. Furthermore, the elastic design of the buffer spring 81 not only buffers the squeezing force of the ice wedge, but also assists the remaining segment in detaching from the inner wall of the arc-extinguishing tube 5 when the melt 9 melts, preventing the ice wedge from hindering the detachment of the remaining segment and causing the melt tube 4 to fail to fall.

[0041] Example 2: The technical solution of this example differs from that of Example 1 in that: (See below) Figures 7-8 An insulating telescopic sleeve 82 is fitted onto the buffer spring 81. A third through hole is provided on the breathable and moisture-proof membrane 62. One end of the insulating telescopic sleeve 82 passes through the third through hole and is connected to the moving contact 64. The other end of the insulating telescopic sleeve 82 is connected to the insulating isolation sleeve 83. The insulating telescopic sleeve 82 and the third through hole are sealed together to prevent water vapor from flowing through the gap between the insulating telescopic sleeve 82 and the third through hole.

[0042] It should be noted that when the melt 9 undergoes axial displacement or the buffer spring 81 undergoes elastic expansion and contraction, the insulating expansion sleeve 82 deforms accordingly with the expansion and contraction of the buffer spring 81, always maintaining a state of wrapping the buffer spring 81, while preventing moisture from entering the arc-extinguishing tube 5 through the gap between the insulating expansion sleeve 82 and the third through hole.

[0043] An insulating telescopic sleeve 82 is fitted onto the buffer spring 81, which provides insulation and protection for the buffer spring 81, preventing surface discharge between the buffer spring 81 and the arc-extinguishing tube 5 and the breathable moisture-proof membrane 62 under high-voltage conditions, thus improving the safety of equipment operation. At the same time, the insulating telescopic sleeve 82 is sealed to the third through hole on the breathable moisture-proof membrane 62, further blocking the channel for water vapor to enter the arc-extinguishing tube 5, enhancing the sealing effect of the moisture-proof sealing mechanism 6. Moreover, the telescopic characteristics of the insulating telescopic sleeve 82 can adapt to the elastic movement of the buffer spring 81, without interfering with the buffering and pushing action of the buffer spring 81. This allows the moisture-proof, insulation, positioning, and buffering functions of the fuse to be highly integrated, comprehensively solving the ice wedge problem in low-temperature freezing environments.

[0044] For a method of using a drop-out fuse, please refer to [link / reference]. Figures 1-10 The above-mentioned drop-out fuse is used; specifically, the following steps are included: Step 1, Primary Sealing: By combining the sealing ring 61 with the breathable and moisture-proof membrane 62, the tiny gap between the inner wall of the fusion tube 4 and the outer wall of the arc-extinguishing tube 5 is directly filled, becoming the first barrier for outdoor moisture to enter the interior of the arc-extinguishing tube 5, blocking most moisture, dust and other impurities from entering. Step 2, Secondary sealing: The sealing ring 65 fills the tiny gap between the moving contact 64 rod and the sealing ring 61 and the breathable moisture-proof membrane 62, forming a seal on the position where the moving contact 64 passes through, forming a second sealing barrier. At the same time, the elasticity of the sealing ring 65 is used to buffer the impact of outdoor wind vibration on the sealing structure. Step 3, Breathable and Moisture-proof: By fixing the breathable and moisture-proof membrane 62 between the sealing ring 61 and the end face of the arc-extinguishing tube 5, the port of the arc-extinguishing tube 5 is fully covered. Its microporous characteristics of being breathable but not water-permeable can block water vapor while allowing gas to pass through; and when the circuit fault fuse 9 melts, a large amount of arc-extinguishing gas generated in the arc-extinguishing tube 5 can be smoothly discharged from the fuse tube 4 through the micropores.

[0045] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A drop-out fuse, comprising an insulator (1), wherein an upper support (2) and a lower support (3) are respectively provided at both ends of the insulator (1), and a fuse tube (4) is provided on one side of the insulator (1), one end of the fuse tube (4) being connected to the upper support (2), and the other end of the fuse tube (4) being hinged to the lower support (3), characterized in that: An arc-extinguishing tube (5) is coaxially inserted into the molten tube (4); a molten material (9) is coaxially inserted into the arc-extinguishing tube (5); both ends of the molten tube (4) are provided with a moisture-proof sealing mechanism (6); the moisture-proof sealing mechanism (6) includes: A sealing ring (61) is disposed between the melting tube (4) and the arc-extinguishing tube (5), and the inner ring of the sealing ring (61) forms a gap (67) with the arc-extinguishing tube (5). A breathable and moisture-proof membrane (62) is provided on the end of the arc-extinguishing tube (5), and the sealing ring (61) is connected to the breathable and moisture-proof membrane (62). Positioning bracket (63), the positioning bracket (63) is fixed to the fusion tube (4); Moving contact (64), which is coaxially inserted into positioning bracket (63); And a sealing ring (65), which is coaxially sleeved on the moving contact (64), and the sealing ring (65) abuts against the sealing retaining ring (61); the sealing retaining ring (61) is provided with a venting groove (66), and the positioning card seat (63) is provided with a first through hole (68); the gas between the molten tube (4) and the arc extinguishing tube (5) is allowed to pass through the venting groove (66), and enter the gap between the positioning card seat (63) and the moving contact (64), and then be discharged through the first through hole (68).

2. A drop-out fuse according to claim 1, characterized in that: The arc-extinguishing tube (5) is equipped with a low-temperature adaptive heating mechanism (7); when the ambient temperature is lower than a certain value, it is allowed to generate heat through the low-temperature adaptive heating mechanism (7); when the ambient temperature is higher than a certain value, the resistance value increases sharply, thereby causing the circuit to be in a cut-off state, so as to achieve adaptive control of the heating temperature.

3. A drop-out fuse according to claim 2, characterized in that: The low-temperature adaptive heating mechanism (7) includes an insulating heat-conducting bracket (71), a miniature heating wire (73), and a low-temperature thermistor (74); the insulating heat-conducting bracket (71) is fixed inside the arc-extinguishing tube (5), and the miniature heating wire (73) and the low-temperature thermistor (74) are both installed on the insulating heat-conducting bracket (71), and the miniature heating wire (73) and the low-temperature thermistor (74) are electrically connected.

4. A drop-out fuse according to claim 3, characterized in that: The insulating heat-conducting bracket (71) has multiple second through holes (72) so that the inside of the arc-extinguishing tube (5) is in a conductive state.

5. A drop-out fuse according to claim 3, characterized in that: Thermally conductive silicone is applied between the inner wall of the insulating thermally conductive bracket (71) and the arc-extinguishing tube (5).

6. A drop-out fuse according to claim 3, characterized in that: The micro heating wire (73) is spirally arranged inside the arc-extinguishing tube (5), and the length of the spiral structure is adapted to the length of the arc-extinguishing tube (5).

7. A drop-out fuse according to claim 1, characterized in that: Both ends of the melt tube (4) are provided with positioning mechanisms (8), which are used to position and buffer the mechanical extrusion force of the ice wedge on the melt (9).

8. A drop-out fuse according to claim 7, characterized in that: The positioning mechanism (8) includes a buffer spring (81), an insulating sleeve (83), and a conductive sheet (84); one end of the buffer spring (81) is connected to the moving contact (64), the insulating sleeve (83) is fitted onto the end of the melt (9), and the other end of the buffer spring (81) is connected to the end of the melt (9) through the conductive sheet (84); allowing a circuit to be formed between the melt (9), the conductive sheet (84), the buffer spring (81), and the moving contact (64).

9. A drop-out fuse according to claim 8, characterized in that: An insulating telescopic sleeve (82) is fitted onto the buffer spring (81), and a third through hole is provided on the breathable and moisture-proof membrane (62). One end of the insulating telescopic sleeve (82) passes through the third through hole and is connected to the moving contact (64), and the other end of the insulating telescopic sleeve (82) is connected to the insulating isolation sleeve (83). The insulating telescopic sleeve (82) and the third through hole are sealed together to prevent water vapor from flowing through the gap between the insulating telescopic sleeve (82) and the third through hole.

10. A method of using a drop-out fuse, characterized in that: The method employs the drop-out fuse according to any one of claims 1-9; specifically, it includes the following steps: Step 1, Primary sealing: By combining the sealing ring (61) with the breathable moisture-proof membrane (62), the tiny gap between the inner wall of the fusion tube (4) and the outer wall of the arc-extinguishing tube (5) is directly filled, becoming the first barrier for outdoor water vapor to enter the interior of the arc-extinguishing tube (5), blocking most water vapor, dust and impurities from entering; Step 2, Secondary sealing: The small gap between the moving contact (64) rod and the sealing ring (61) and the breathable moisture-proof membrane (62) is filled by the sealing rubber ring (65) to form a seal on the position where the moving contact (64) passes through, forming a second sealing barrier. At the same time, the elasticity of the sealing rubber ring (65) is used to buffer the impact of outdoor wind vibration on the sealing structure. Step 3, breathable and moisture-proof: By fixing the breathable and moisture-proof membrane (62) between the sealing ring (61) and the end face of the arc-extinguishing tube (5) port, the arc-extinguishing tube (5) port is fully covered. Its microporous characteristics of being breathable but not water-permeable can block water vapor while allowing gas to pass through. When the circuit fault fuse (9) melts, a large amount of arc-extinguishing gas generated in the arc-extinguishing tube (5) can be smoothly discharged from the fuse tube (4) through the micropores.

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