A pressure-regulated arc extinguishing circuit breaker

Abstract

The application relates to the technical field of circuit breakers and discloses a gas-pressure-regulated arc-extinguishing circuit breaker, which comprises a shell, movable and static contacts and an arc-extinguishing chamber arranged in the shell, and a cover plate fixedly installed on the shell, wherein a convex strip extending towards the shell is arranged around the cover plate, a groove matched with the convex strip is arranged around the shell, the convex strip is fixedly installed in the groove, a cavity is arranged between the top end surface of the convex strip and the groove, an elastic air bag pipe capable of adjusting the expansion volume according to the change of the gas pressure in the shell is fixedly installed in the cavity, the air bag pipe is fixedly installed in the groove, and the air bag pipe is communicated with the environment in the shell and the external environment through an inner one-way valve and an outer one-way valve at two ends respectively; when the gas pressure in the shell of the circuit breaker is suddenly increased due to the electric arc, the air bag pipe is driven to expand by the gas pressure and is pressed tightly in the radial direction, the convex strip is tightly combined with the wall surface of the groove, and the problem that the traditional seal is prone to leakage or deformation under high pressure is effectively solved.

Description

Technical Field

[0001] This invention relates to the field of circuit breaker technology, specifically to a pneumatically controlled arc-extinguishing circuit breaker. Background Technology

[0002] Circuit breakers are protective devices used in power systems to disconnect or connect circuits. Their core function is to control the flow of current through the opening and closing of internal contacts, and to extinguish electric arcs quickly using an insulating medium (such as SF6 gas, vacuum, or solid insulating materials). The sealing performance of a circuit breaker is a core factor determining its reliability. Its structure typically includes housing seals, dynamic seals, and static seals, involving multi-level sealing designs such as metal bellows, elastic sealing rings, and composite insulating materials to ensure stable maintenance of the arc-extinguishing medium, isolation from external environmental contaminants, and long-term airtightness of mechanical linkage components.

[0003] However, existing miniature circuit breakers cannot accurately determine whether an electric arc has occurred between the internal contacts. Furthermore, current miniature circuit breakers typically lack sealing capabilities, and disassembling sealed circuit breakers requires specialized personnel and specific conditions, making disassembly difficult and prone to sealing failure during subsequent use. Moreover, their sealing performance cannot be dynamically adjusted based on internal conditions (such as the generation of an electric arc). If the sealing is good, the presence of an electric arc inside the circuit breaker can easily lead to various problems. Summary of the Invention

[0004] (I) Technical problem to be solved: In view of the shortcomings of the existing technology, the present invention provides a pneumatically adjustable arc extinguishing circuit breaker, which has the advantage of dynamically adjusting the sealing performance according to the gas inside the circuit breaker, and solves the problems that the sealing structure of the traditional circuit breaker is prone to leakage or deformation under internal high pressure, and cannot dynamically adjust the sealing performance according to the operating conditions.

[0005] (II) Technical Solution: To achieve the above-mentioned objective of dynamically adjusting the sealing performance based on the internal gas of the circuit breaker, the present invention provides the following technical solution: A pneumatically controlled arc-extinguishing circuit breaker, comprising a housing, wherein dynamic and static contacts and an arc-extinguishing chamber are disposed within the housing, and a cover plate is fixedly installed on the housing. The cover plate has protrusions extending towards the housing around its perimeter, and grooves matching the protrusions are disposed around the perimeter of the housing. The protrusions are fixedly installed within the grooves, and a cavity is provided between the top surface of the protrusion and the groove. The cavity is fixedly... An elastic airbag tube is fixedly installed in the groove, and its expansion volume is adjusted according to the changes in air pressure inside the shell. The airbag tube is fixedly installed in the groove, and its two ends are connected to the internal environment of the shell and the external environment through an inner one-way valve and an outer one-way valve, respectively. The inner one-way valve allows gas inside the shell to be injected into the airbag tube in one direction, and the outer one-way valve allows gas inside the airbag tube to be discharged to the external environment in one direction. When the air pressure inside the shell increases, the airbag tube expands under the action of air pressure and presses against the two protrusions on both sides, so that the protrusions and the inner wall of the groove form a dynamic sealing fit.

[0006] Preferably, a telescopic spring is coaxially rotatably mounted on the airbag tube, and two or more sets of limiting blocks are fixedly installed in the groove. One end of the telescopic spring is fixedly connected to the limiting block, and the other end of the telescopic spring is fixedly connected to a slider. The slider is slidably installed in the groove. Two or more sets of sliding locking blocks are also fixedly mounted on the telescopic spring. The sliding locking blocks have protruding buckle structures fixedly connected to both sides, and the protrusions have sliding grooves and limiting grooves corresponding to the buckle structures. The sliding grooves are connected to the limiting grooves. During the installation of the protrusions and the groove, the buckle structures are inserted into the sliding grooves. When the airbag tube expands, the airbag tube radially pushes up the telescopic spring, causing it to axially extend and radially expand outward, driving the sliding locking blocks to move axially. The buckle structures slide along the sliding grooves to the limiting grooves and restrict the movement of the protrusions in a direction perpendicular to the bottom surface of the groove.

[0007] Preferably, when the airbag tube expands, the telescopic spring expands radially outward and presses the protrusions on both sides of the spring against the end faces of the groove, so that the protrusions and the groove form a spiral-shaped tight seal.

[0008] Preferably, the sliding lock block has a sliding hole, the telescopic spring is fixedly connected to the sliding hole, a slide rail is provided on the bottom surface of the groove, the sliding lock block is slidably connected to the slide rail, and the slider is slidably connected to the slide rail.

[0009] Preferably, when the airbag tube is not inflated, one end face of the sliding lock block is pressed against the limiting block.

[0010] Preferably, a telescopic bellows is provided between the sliding lock block and the limiting block. When the sliding lock block slides, the sliding lock block drives the telescopic bellows to extend and retract.

[0011] Preferably, the limiting block is provided with a multi-stage retaining plate that can extend and adjust the extension amount of the telescopic corrugated pipe. One end of the multi-stage retaining plate is fixedly connected to the limiting block, and the other end of the multi-stage retaining plate is fixedly connected to the telescopic corrugated pipe.

[0012] Preferably, a handle is rotatably connected to the housing, and the two ends of the handle are respectively sealed to the housing and the cover plate.

[0013] Preferably, both ends of the airbag tube are fixedly connected to the housing, and the inner one-way valve is connected to the arc-extinguishing chamber; the convex strip is a flexible sealing strip.

[0014] (III) Beneficial Effects: Compared with the prior art, the present invention provides a pneumatically controlled arc-extinguishing circuit breaker, which has the following beneficial effects:

[0015] 1. This pneumatically controlled arc-extinguishing circuit breaker utilizes a combination of an air bladder tube structure and an external one-way valve structure. When the internal gas pressure rises sharply due to an electric arc, the air bladder tube expands under pressure and radially presses against the protruding strip, ensuring a tight fit between the protruding strip and the groove wall. Simultaneously, the internal and external one-way valves automatically adjust the gas capacity within the air bladder tube according to the gas pressure threshold. This enhances sealing performance under high-pressure arc conditions while maintaining a moderate sealing state under normal operating conditions. It effectively solves the problem of leakage or deformation of traditional seals under high pressure, while avoiding internal pressure accumulation caused by over-sealing and seal relaxation failure under low-pressure conditions. This improves the sealing reliability and safety of the circuit breaker under different operating conditions.

[0016] 2. This pneumatically controlled arc-extinguishing circuit breaker, through the combined use of a telescopic spring structure and an air bladder tube structure, transforms the linear expansion force of the air bladder tube into a continuously distributed spiral clamping force. During the expansion of the air bladder tube, the telescopic spring undergoes a combined deformation of radial outward expansion and axial elongation. Its spiral trajectory forms a uniformly distributed spiral clamping force on the inner surface of the convex strip. Compared with traditional discrete point contact seals, the telescopic spring allows the sealing pressure to be continuously transmitted along the spiral path, eliminating the problem of sealing material wear or stress concentration caused by local high pressure. At the same time, the elastic characteristics of the telescopic spring can absorb the mechanical vibration energy during the operation of the circuit breaker. Through the frictional damping and elastic restoring force between the telescopic spring coils, the gap of the sealing surface is dynamically compensated, effectively preventing sealing failure caused by vibration and greatly extending the service life of the sealing components.

[0017] 3. This pneumatically controlled arc-extinguishing circuit breaker utilizes a combination of a telescopic spring structure and a sliding locking block structure to create a dynamic locking mechanism triggered by pneumatic pressure. When the high pressure inside the housing drives the air bladder tube to expand, the axial extension of the telescopic spring causes the sliding locking block to move along the slide rail, causing the snap-fit ​​structure to embed into the protruding limiting groove to form a vertical constraint. Under high-pressure conditions, this automatically strengthens the connection between the cover plate and the housing. This state is only activated under high pressure, ensuring structural stability under extreme conditions while preserving deformation compensation space for the sealing surface under normal conditions. In addition, combined with the telescopic adjustment function of the multi-stage snap-fit ​​plate, the stroke of the sliding locking block can be controlled by changing the unfolded length of the snap-fit ​​plate. Attached Figure Description

[0018] Figure 1 This is a three-dimensional structural schematic diagram of the pneumatically controlled arc-extinguishing circuit breaker of the present invention;

[0019] Figure 2 This is a top view of the structure of the pneumatically controlled arc-extinguishing circuit breaker of the present invention;

[0020] Figure 3 for Figure 2 NN-direction sectional view;

[0021] Figure 4 This is a three-dimensional schematic diagram of the housing structure of the pneumatically controlled arc-extinguishing circuit breaker of the present invention;

[0022] Figure 5 This is a front view of the housing structure of the pneumatically controlled arc-extinguishing circuit breaker of the present invention;

[0023] Figure 6 This is a schematic diagram of the groove structure of the pneumatically controlled arc-extinguishing circuit breaker of the present invention;

[0024] Figure 7 This is a schematic diagram showing the moving direction of the snap-fit ​​structure and the limiting groove structure of the pneumatically controlled arc-extinguishing circuit breaker in this invention.

[0025] Figure 8 This is a schematic diagram of the gas bladder tube structure of the pneumatically controlled arc-extinguishing circuit breaker of the present invention after expansion.

[0026] Figure 9 for Figure 3 Enlarged view of the local structure at point A;

[0027] Figure 10 This is a three-dimensional schematic diagram of the sliding locking block structure of the pneumatically controlled arc-extinguishing circuit breaker of the present invention;

[0028] Figure 11 This is a three-dimensional schematic diagram of the cover plate structure of the pneumatically controlled arc-extinguishing circuit breaker of the present invention.

[0029] Figure 12 for Figure 11 Enlarged view of the local structure at point B;

[0030] Figure 13 This is a schematic diagram of the telescopic bellows structure of the pneumatically controlled arc-extinguishing circuit breaker of the present invention.

[0031] Figure 14 for Figure 5 Enlarged view of the local structure at point C.

[0032] In the diagram: 1. Housing; 11. Moving and stationary contacts; 12. Arc extinguishing chamber; 13. Handle; 2. Groove; 21. Limiting block; 22. Slide rail; 3. Cover plate; 31. Raised strip; 311. Sliding groove; 312. Limiting groove; 4. Airbag tube; 41. Telescopic spring; 42. Sliding lock block; 421. Snap-fit ​​structure; 422. Sliding hole; 43. Telescopic bellows; 44. Multi-stage locking plate; 46. Slider; 5. Internal check valve; 6. External check valve. Detailed Implementation

[0033] 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.

[0034] Please see Figures 1-9A pneumatically controlled arc-extinguishing circuit breaker includes a housing 1, within which are moving and stationary contacts 11 and an arc-extinguishing chamber 12. A cover plate 3 is also fixedly installed on the housing 1. The cover plate 3 has protrusions 31 extending towards the housing 1 around its perimeter. The housing 1 also has grooves 2 that match the protrusions 31, with the grooves 2 having a U-shaped open cross-section. The cross-sectional dimensions of the protrusions 31 and the opening clearance of the grooves 2 form an interference fit. A protruding strip 31 is fixedly installed in the groove 2, and an annular cavity is reserved between the top end face of the protruding strip 31 and the bottom of the groove 2. An elastic airbag tube 4, which adjusts its expansion volume according to the change of air pressure inside the shell 1, is fixedly installed in the cavity. The airbag tube 4 is fixedly installed in the groove 2, and its two ends are connected to the internal environment of the shell 1 and the external environment through an inner one-way valve 5 and an outer one-way valve 6, respectively. The inner one-way valve 5 allows gas inside the shell 1 to be injected into the airbag tube 4 in one direction, and the outer one-way valve 6 allows gas inside the airbag tube 4 to be discharged to the external environment in one direction. Its valve core is made of high-temperature resistant ceramic material to ensure reliable opening and closing under the high temperature environment of electric arc. A spring-loaded conical sealing plug is configured inside the valve body, and the pressure relief threshold is set by adjusting the spring preload. When the air pressure inside the shell 1 exceeds the set threshold, high-temperature gas is injected into the airbag tube 4 in one direction through the inner one-way valve 5, driving it to expand radially; when the pressure inside the airbag tube 4 exceeds the opening pressure of the outer one-way valve 6, the excess gas is automatically discharged. This design ensures that when the cover plate 3 is assembled with the housing 1, the protrusion 31 first forms a primary sealing contact with the side wall of the groove 2, while the airbag tube 4 inside the cavity serves as a secondary dynamic sealing actuator. When no electric arc is generated inside the circuit breaker, the airbag tube 4 maintains a basic expansion state, applying appropriate radial restraint to the protrusion 31 through pre-tightening force, ensuring airtightness under normal operating conditions while avoiding stress fatigue caused by rigid compression. When the air pressure inside the housing 1 increases, the airbag tube 4 expands under the air pressure and presses against the protrusions 31 on both sides, so that the protrusions 31 form a dynamic sealing fit with the inner wall of the groove 2.

[0035] Please see Figures 6-12 A telescopic spring 41 is coaxially mounted on the airbag tube 4. The telescopic spring 41 is made of high-temperature resistant nickel-based alloy wire wound into a variable pitch spiral structure. Two or more sets of limiting blocks 21 are also fixedly installed in the groove 2. The limiting blocks 21 are welded and fixed to the bottom of the groove 2. One end of the telescopic spring 41 is fixedly connected to the limiting block 21. The limiting block 21 is used to fix one end of the telescopic spring 41, ensuring that the telescopic spring 41 can extend, contract, and deform in a predetermined direction when subjected to the expansion force of the airbag tube 4. Please refer to Figure 14The other end of the telescopic spring 41 is fixedly connected to a slider 46, which is slidably installed in the groove 2. The slider 46 forms a sliding pair with the bottom slide rail 22 of the groove 2 through a dovetail groove structure. The slider 46 forms a sliding pair with the bottom slide rail 22 of the groove 2 through the dovetail groove structure, which can provide guidance and limit for the extension and deformation of the telescopic spring 41, ensuring that the telescopic spring 41 can move along a predetermined trajectory when subjected to the expansion force of the airbag tube 4. Two or more sets of sliding locking blocks 42 are also fixedly installed on the telescopic spring 41. The sliding locking blocks 42 are fixedly connected to both sides with protruding T-shaped buckle structures 421, and the protruding strip 31 has a sliding groove 311 and a limiting groove 312 corresponding to the buckle structure 421. The sliding groove 311 and the limiting groove 312 are connected to each other. The sliding groove 311 and the limiting groove 312 on the protruding strip 31 are used to cooperate with the movement of the sliding locking blocks 42 and the T-shaped buckle structures 421. During the initial installation phase, the snap-fit ​​structure 421 is inserted into the sliding groove 311; when the airbag tube 4 inflates, the snap-fit ​​structure 421 slides along the sliding groove 311 into the limiting groove 312 to form a constraint; please refer to Figure 7 and Figure 8 When the airbag tube 4 expands, driving the telescopic spring 41 to extend axially, the sliding locking block 42 moves along the slide rail 22, causing the buckle structure 421 to slide from the horizontal section of the sliding groove 311 into the limiting groove 312. At this time, the buckle structure 421 is embedded in the limiting groove 312 to form a vertical constraint, preventing the cover plate 3 from displacing under the action of internal pressure.

[0036] Please see Figure 8 When the airbag tube 4 inflates, the telescopic spring 41 expands radially outward and presses its two side protrusions 31 against the two end faces of the groove 2, forming a spiral seal between the protrusions 31 and the groove 2. Please refer to Figures 6-14 A sliding hole 422 is provided inside the sliding locking block 42. The telescopic spring 41 is fixedly connected to the sliding hole 422. A slide rail 22 is provided on the bottom end surface of the groove 2. The sliding locking block 42 is slidably connected to the slide rail 22, and the slider 46 is slidably connected to the slide rail 22. The design of the sliding hole 422 and the slide rail 22 provides guidance and limitation for the extension and movement of the telescopic spring 41 and the sliding locking block 42. This ensures that when the telescopic spring 41 is subjected to the inflation force of the airbag tube 4, it can smoothly extend, contract, and deform along a predetermined trajectory. At the same time, the sliding locking block 42 can also move accurately along the slide rail 22, thereby achieving the predetermined sealing and locking functions. When the airbag tube 4 is not inflated, one end face of the sliding locking block 42 is pressed against the limiting block 21. Please refer to Figure 13A telescopic bellows 43 is provided between the sliding locking block 42 and the limiting block 21. When the sliding locking block 42 slides, it drives the telescopic bellows 43 to extend and retract. The limiting block 21 is provided with a multi-stage locking plate 44 that can adjust the extension and retraction of the telescopic bellows 43. One end of the multi-stage locking plate 44 is fixedly connected to the limiting block 21, and the other end is fixedly connected to the telescopic bellows 43. The multi-stage locking plate 44 assembly is composed of multiple layers of 304 stainless steel sheets, and adjacent sheets are positioned by interlocking teeth. The maximum extension and retraction of the telescopic bellows 43 is limited by rotating the adjusting screw to change the unfolded length of the laminated sheets. This design allows the stroke of the sliding locking block 42 to be adjusted in multiple positions, making it easy to set different pressure response thresholds according to actual working conditions. A handle 13 is also rotatably connected to the housing 1, and the two ends of the handle 13 are sealed to the housing 1 and the cover plate 3, respectively. Both ends of the airbag tube 4 are fixedly connected to the housing 1. The inner one-way valve 5 is connected to the arc-extinguishing chamber 12. The inner one-way valve 5 is connected to the arc-extinguishing chamber 12, which can ensure that when an electric arc is generated in the arc-extinguishing chamber 12, causing the air pressure to rise, the airbag tube 4 can respond quickly and expand to achieve dynamic sealing. The convex strip 31 adopts a flexible sealing strip.

[0037] Working Principle: During use, this invention can dynamically adjust the sealing strength according to the changes in air pressure inside the circuit breaker housing 1, and avoid leakage or deformation caused by local stress concentration under high pressure in traditional planar seals. In the sealing process of the miniature air circuit breaker, the housing 1 and the cover plate 3 are sealed by the groove 2 and the convex strip 31 structure. During the sealing installation process, a certain amount of gas is initially stored in the air bladder tube 4 located in the groove 2 to maintain the initial expansion of the air bladder tube 4. After the convex strip 31 structure is installed in the groove 2, the outer end faces of the two convex strips 31 will contact the end faces of the two sides of the groove 2, and the inner end faces of the convex strips 31 will contact the wall of the air bladder tube 4. At the same time, the amount of gas inside the air bladder tube 4 is controlled by the inner one-way valve 5 and the outer one-way valve 6. The opening pressure threshold of the outer one-way valve 6 is lower than the tolerance limit of the air bladder tube 4 material. When the pressure inside the housing 1 increases and the air bladder tube 4 expands to near the deformation critical point, the outer one-way valve 6 opens first to release pressure. When the circuit breaker is closed, the electric arc generated by the separation of the moving and stationary contacts 11 causes an increase in air pressure inside the arc-extinguishing chamber 12 and the housing 1. At this time, high-pressure gas is injected unidirectionally into the elastic air bladder tube 4 in the groove 2 through the inner one-way valve 5. The air bladder tube 4 expands radially under the air pressure, and its outer wall presses the inner end face of the protrusion 31 to both sides, so that the outer end face of the flexible material protrusion 31 forms a tight fit with the rigid end faces on both sides of the groove 2. In this process, the expansion amount of the air bladder tube 4 is adaptively adjusted through the coordinated control of the inner one-way valve 5 and the outer one-way valve 6. When the air pressure inside the housing 1 exceeds the opening threshold of the outer one-way valve 6, the excess gas is discharged outward through the outer one-way valve 6 to avoid damage to the air bladder tube 4 due to over-expansion; when the air pressure inside the housing 1 drops, the inner one-way valve 5 stops filling the air bladder tube 4 with gas. This achieves automatic enhanced sealing when an electric arc is generated, while maintaining a moderate seal in non-operating conditions, avoiding the risk of internal pressure accumulation caused by over-sealing and solving the leakage problem caused by the loosening of the sealing material under low pressure. Furthermore, the inner check valve 5 and the outer check valve 6 can effectively maintain the pressure stability inside the housing 1.

[0038] During the expansion of the airbag tube 4, the spiral telescopic spring 41, coaxially sleeved on the outer wall of the airbag tube 4, is subjected to the radial expansion force of the airbag tube 4. The diameter of the telescopic spring 41 undergoes an outward elastic deformation, while the spring axis elongates. At this time, one end of the telescopic spring 41 is fixedly connected to the limiting block 21 on the inner wall of the groove 2, and the other end is connected to the slider 46 and freely extended. The surface of the telescopic spring 41 contacts the inner end face of the protrusion 31. As the spring coil expands radially outward, the spiral trajectory of the telescopic spring 41 forms a continuous spiral pressing force distribution on the inner surface of the protrusion 31. This pressing force is evenly transmitted spirally along the side wall of the groove 2, transforming the single radial linear pressure transmitted by the airbag tube 4 into a spiral pressing force continuously distributed along the spiral. By converting the linear expansion force into a continuously distributed spiral pressing force through the telescopic spring 41, local high-pressure wear or leakage caused by discrete point contact in traditional seals can be effectively avoided, greatly improving the reliability and service life of the seal. Furthermore, when the circuit breaker is subjected to mechanical vibration, the elastic deformation of the extension spring 41 can absorb the vibration energy through the frictional damping and elastic restoring force between the spring coils, preventing the contact surface between the protrusion 31 and the groove 2 from gaps caused by vibration.

[0039] During the radial expansion and axial extension of the telescopic spring 41, its axial length increases accordingly, thereby driving the sliding locking block 42 to slide axially along the slide rail 22 on the bottom surface of the groove 2. Simultaneously, the latching structure 421, driven by the sliding locking block 42, moves directionally within the sliding groove 311 of the protrusion 31. In the initial installation stage, when the protrusion 31 engages with the groove 2, the latching structure 421 of the sliding locking block 42 is already inserted into the sliding groove 311 of the protrusion 31. When the airbag tube 4 expands, causing the telescopic spring 41 to deform, the sliding locking block 42 displaces axially along the slide rail 22, and the latching structure 421 slides from the starting end of the sliding groove 311 towards the limiting groove 312. When the latching structure 421 reaches the position of the limiting groove 312, under the vertical guidance of the limiting groove 312, the latching structure 421 embeds itself into the limiting groove 312 in a direction perpendicular to the bottom surface of the groove 2. At this time, the limiting groove 312 and the snap-fit ​​structure 421 form a constraint, preventing the protrusion 31 from displacing in the direction perpendicular to the bottom surface of the groove 2, thereby strengthening the fixation between the protrusion 31 and the groove 2. At the same time, this enhanced fixation only takes effect after the air pressure inside the housing 1 increases. When the air pressure inside the housing 1 increases due to the generation of an electric arc, the airbag tube 4 expands, driving the telescopic spring 41 to deform, which drives the snap-fit ​​structure 421 of the sliding lock block 42 to slide along the sliding groove 311 to the locking position of the limiting groove 312, forming a constraint on the cover plate 3 perpendicular to the bottom surface of the groove 2, effectively suppressing the possible displacement and loosening phenomenon between the cover plate 3 and the housing 1 under high pressure. Under normal working conditions, when the air pressure inside the housing 1 is insufficient to cause the airbag tube 4 to not fully expand, this part of the structure remains unconstrained, avoiding the stress fatigue of the sealing surface caused by traditional rigid connection, providing a moderate deformation compensation space for the sealing assembly, and also avoiding the danger of disassembling the cover plate 3 due to high pressure gas inside the housing 1.

[0040] When the circuit breaker is used in different operating conditions or maintenance stages and the stroke of the sliding locking block 42 needs to be adjusted, the telescopic design of the multi-stage clamping plate 44 can achieve dynamic control of the sealing strength. The multi-stage clamping plate 44 is composed of multiple metal plates that are nested together in sequence. The multi-stage clamping plate 44 is driven to expand or contract axially by adjusting the adjusting bolt on the rotating limit block 21. When the multi-stage clamping plate 44 extends, since one end is fixedly connected to the limit block 21 and the other end is connected to the telescopic bellows 43, its extension will restrict more sections of the telescopic bellows 43 from extending, thereby reducing the telescopic length of the telescopic bellows 43; conversely, when it contracts, the extension distance increases. When the air bladder tube 4 expands and drives the sliding locking block 42 to slide, the free stroke of the telescopic bellows 43 is limited by the length of the multi-stage clamping plate 44, thereby precisely controlling the movement distance of the latching structure 421 of the sliding locking block 42 in the sliding groove 311 and the telescopic length of the telescopic spring 41. Operators can choose to fully lock the multi-level locking plate 44 with the buckle structure 421 or partially retract the multi-level locking plate 44 in a semi-locked state according to actual needs, so as to achieve different levels of air pressure response threshold settings while ensuring sealing reliability.

[0041] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0042] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A pneumatically controlled arc-extinguishing circuit breaker, comprising a housing (1), wherein moving and stationary contacts (11) and an arc-extinguishing chamber (12) are disposed within the housing (1), and a cover plate (3) is fixedly installed on the housing (1), wherein a protrusion (31) extending toward the housing (1) is disposed around the cover plate (3), and a groove (2) matching the protrusion (31) is disposed around the housing (1), wherein the protrusion (31) is fixedly installed in the groove (2), characterized in that: A cavity is provided between the top surface of the protrusion (31) and the groove (2). An elastic airbag tube (4) that adjusts its expansion volume according to the change of air pressure inside the shell (1) is fixedly installed in the cavity. The airbag tube (4) is fixedly installed in the groove (2). The two ends of the airbag tube (4) are connected to the internal environment of the shell (1) and the external environment through an inner one-way valve (5) and an outer one-way valve (6), respectively. The inner one-way valve (5) allows the gas inside the shell (1) to be injected into the airbag tube (4) in one direction. The outer one-way valve (6) allows the gas inside the airbag tube (4) to be discharged to the external environment in one direction. When the air pressure inside the shell (1) increases, the airbag tube (4) expands under the action of air pressure and presses against the protrusions (31) on both sides, so that the protrusions (31) and the inner wall of the groove (2) form a dynamic sealing fit. A telescopic spring (41) is coaxially mounted on the airbag tube (4). Two or more sets of limiting blocks (21) are also fixedly installed in the groove (2). One end of the telescopic spring (41) is fixedly connected to the limiting block (21), and the other end of the telescopic spring (41) is fixedly connected to a slider (46). The slider (46) is slidably installed in the groove (2). Two or more sets of sliding locking blocks (42) are also fixedly mounted on the telescopic spring (41). The sliding locking blocks (42) have protruding buckle structures (421) fixedly connected on both sides. The protruding strip (31) has openings corresponding to the buckle structures (421). The sliding groove (311) and the limiting groove (312) are connected. During the installation of the protrusion (31) and the groove (2), the buckle structure (421) is inserted into the sliding groove (311). When the airbag tube (4) expands, the airbag tube (4) radially pushes up the telescopic spring (41) to make it axially extend and radially expand outward, driving the sliding lock block (42) to move axially. The buckle structure (421) slides along the sliding groove (311) to the limiting groove (312) and restricts the movement of the protrusion (31) in the direction perpendicular to the bottom end face of the groove (2).

2. The pneumatically controlled arc-extinguishing circuit breaker according to claim 1, characterized in that: When the airbag tube (4) expands, the telescopic spring (41) expands radially outward and presses the protrusions (31) on both sides of the groove (2) against the end faces of both sides, so that the protrusions (31) and the groove (2) form a spiral-shaped tight seal.

3. The pneumatically controlled arc-extinguishing circuit breaker according to claim 1, characterized in that: The sliding lock block (42) has a sliding hole (422) inside. The telescopic spring (41) is fixedly connected to the sliding hole (422). A slide rail (22) is provided on the bottom surface of the groove (2). The sliding lock block (42) is slidably connected to the slide rail (22). The slider (46) is slidably connected to the slide rail (22).

4. The pneumatically controlled arc-extinguishing circuit breaker according to claim 1, characterized in that: When the airbag tube (4) is not inflated, one end face of the sliding lock block (42) is pressed against the limiting block (21).

5. A pneumatically controlled arc-extinguishing circuit breaker according to claim 1, characterized in that: A telescopic bellows (43) is provided between the sliding lock block (42) and the limiting block (21). When the sliding lock block (42) slides, the sliding lock block (42) drives the telescopic bellows (43) to extend and retract.

6. A pneumatically controlled arc-extinguishing circuit breaker according to claim 2, characterized in that: The limiting block (21) is provided with a multi-level clamping plate (44) that can extend and adjust the extension amount of the telescopic corrugated pipe (43). One end of the multi-level clamping plate (44) is fixedly connected to the limiting block (21), and the other end of the multi-level clamping plate (44) is fixedly connected to the telescopic corrugated pipe (43).

7. A pneumatically controlled arc-extinguishing circuit breaker according to claim 1, characterized in that: A handle (13) is rotatably connected to the housing (1), and the two ends of the handle (13) are respectively sealed to the housing (1) and the cover plate (3).

8. A pneumatically controlled arc-extinguishing circuit breaker according to claim 1, characterized in that: Both ends of the airbag tube (4) are fixedly connected to the shell (1); the protrusion (31) is a flexible sealing strip.

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