Medium or high voltage circuit breaker

Abstract

The invention relates to a medium or high voltage circuit breaker (10) comprising a first (11) and a second (12) electrical arcing contact axially movable relative to each other between an open position, in which the arcing contacts are separated, and a closed position, in which the arcing contacts (11, 12) are in contact. The circuit breaker (10) comprises an auxiliary nozzle (22) made of a fluorocarbon polymer or made of polyethylene, polyamide, polyimide, polyketone, polyacetal, polysulfone, polysulfide, which is connected to a support member (20) via a threaded connection (24). To prevent loosening caused by operational vibrations or shock waves during arcing events, the threaded connection is equipped with a loosening prevention mechanism. Various embodiments of the loosening prevention device (25) are disclosed, including a compressible annular member (27) which increases the friction between the threads, a spring loaded pin (32) which interacts with a profiled slot pocket (36), a resilient ratchet (39) which engages with a recess (41), and an annular rim (47) which cooperates with an annular protrusion (45). These mechanisms ensure that the auxiliary nozzle (22) remains firmly attached to the support member (20) in the screwed-in position, while allowing for easy assembly. The invention provides a robust and reliable connection between the auxiliary nozzle (22) and the support member (20), enhancing the performance and durability of the circuit breaker (10) under high mechanical and thermal stress conditions.

Description

Technical Field

[0001] This invention relates to medium-voltage or high-voltage circuit breakers, including "dead cans," "metal-encased," "live cans," and "self-blowing" types. More specifically, this invention relates to an auxiliary nozzle connected to a seat member of a first electrically arcing contact designed as a contact socket. In this context, the seat member may be referred to as a support member. Background Technology

[0002] Document CN206401229U discloses an improved moving contact structure for the arc-extinguishing chamber of a 40.5kV sulfur hexafluoride (SF6) circuit breaker. This disclosure focuses on optimizing the structural design of the moving contact to enhance arc-extinguishing performance, improve operational reliability, and extend the device's lifespan.

[0003] Document CN220710986U discloses a gas-insulated switchgear (GIS) that uses an environmentally friendly insulating gas as a substitute for sulfur hexafluoride (SF6), addressing the environmental problems associated with this greenhouse gas. The GIS incorporates a modular design with auxiliary expansion units to facilitate system expansion and maintenance.

[0004] US Patent 11,462,377B2 discloses a circuit breaker with axially movable arc-initiating contacts, operable between an open position with contacts separated and a closed position with contacts in contact. The circuit breaker is characterized by an arc-blowing nozzle having upstream and downstream end portions relative to the arc-controlling gas flow. The nozzle includes a fluorocarbon polymer auxiliary nozzle, such as one made of polytetrafluoroethylene (PTFE), providing high mechanical and thermal properties. Alternatively, the auxiliary nozzle may be made of polyethylene, polyamide, polyimide, polyketone, polyacetal, polysulfone, or polysulfide.

[0005] However, connecting the dielectric-assisted nozzle to the arc-starting contact support is challenging. Previous methods (such as snap-fit ​​connections using PTFE-assisted nozzles with segmented cantilever rings) exhibit mechanical weaknesses under high tension, especially during arcing events. These weaknesses affect the reliability and durability of the connection. Summary of the Invention

[0006] The object of this invention is to provide an improved connection between a dielectric-assisted nozzle and an arc-initiating contact support. This object is achieved by a medium-voltage or high-voltage circuit breaker as defined in claim 1.

[0007] The medium-voltage or high-voltage circuit breaker of the present invention includes a first arcing contact and a second arcing contact, which are axially movable relative to each other. The circuit breaker operates between an open position in which the arcing contacts are separated and a closed position in which the arcing contacts are in contact. The first arcing contact includes a contact opening on a first side facing the second arcing contact and is configured to receive the second arcing contact within the contact opening in the closed position.

[0008] The first arc-starting contact is mounted in a support member on a second side opposite to the second arc-starting contact and in a (dielectric) auxiliary nozzle on the first side. The auxiliary nozzle includes an auxiliary nozzle opening aligned with the contact opening of the first arc-starting contact and is made of a fluorocarbon polymer. Alternatively, the auxiliary nozzle may be made of polyethylene, polyamide, polyimide, polyketone, polyacetal, polysulfone, or polysulfide.

[0009] A key aspect of this invention is the threaded connection between the support member and the auxiliary nozzle. Other connections (such as clamping connections) that often rely on cantilever sections or snap-fit ​​mechanisms to fasten components (such as auxiliary nozzles) to their supports exhibit significant drawbacks under the operating conditions of medium- or high-voltage circuit breakers. A major limitation of clamping connections is their susceptibility to mechanical failure under high tensile forces, such as during arcing events or those caused by vibration and shock waves. Cantilever sections in clamping designs are inherently weak and prone to deformation or breakage under such stresses. This affects the reliability and durability of the connection, potentially leading to the displacement of the dielectric auxiliary nozzle. In contrast, the threaded connection provided in this invention distributes forces evenly along the threaded joint, rather than concentrating forces at a specific point as in clamping designs. This makes the connection more robust and resistant to mechanical stress.

[0010] The threaded connection also includes an anti-loosening mechanism configured to prevent movement of the auxiliary nozzle relative to the support member in the screw-out direction. The fluorocarbon polymer material of the auxiliary nozzle exhibits non-stick and low-friction properties, which are beneficial for mechanical performance but also increase the risk of loosening during operation. During an arc initiation event, the shock wave generated by the arc and the resulting arc-extinguishing gas can be transmitted to the support member and the auxiliary nozzle. These forces, combined with the low-friction properties of the fluorocarbon polymer, can cause the threaded connection to loosen over time. The anti-loosening mechanism prevents such movement, ensuring that the auxiliary nozzle remains firmly attached to the support member, even under high mechanical stress.

[0011] Medium-voltage or high-voltage circuit breakers are electrical switching devices designed to interrupt the flow of current in a circuit under normal operating conditions or during fault conditions such as short circuits or overloads. They are specifically engineered to operate in systems with voltage ratings typically classified as follows: - Medium voltage (MV): Operates in the voltage range of 1kV to 36kV, and is often used in industrial facilities, power distribution networks, and infrastructure systems; or - High voltage (HV): Operates at voltages above 36kV, typically used in transmission networks and substations for large-scale power distribution.

[0012] Medium- or high-voltage circuit breakers are crucial for maintaining electrical safety, ensuring system stability, and protecting equipment from damage. They employ advanced arc-extinguishing mechanisms, such as gas (e.g., SF6 or environmentally friendly alternatives), vacuum, or air blowing, to extinguish the arc that forms during a current interruption.

[0013] These circuit breakers are also classified based on their design and function, including types such as "dead tank", "live tank", "jet", and "self-blowing" circuit breakers.

[0014] Auxiliary nozzles can be made of various fluorocarbon polymers, such as polytetrafluoroethylene (PTFE), trifluorochloroethylene (CTFE), perfluorocyclic olefins (PFCA), vinyl fluoride (VF1), vinylidene fluoride (VDF or VF2), hexafluoropropylene (HFP), perfluoropropyl vinyl ether (PPVE), or perfluoromethyl vinyl ether (PMVE). Support components are typically made of metal, such as aluminum, steel, copper, or other suitable materials.

[0015] Preferably, the auxiliary nozzle includes an auxiliary nozzle thread, and the support member includes a support thread, wherein the auxiliary nozzle thread and the support thread can engage with each other.

[0016] The anti-loosening device is specifically configured to be effective only when the auxiliary nozzle and the support component are in the screw-in end position, wherein the auxiliary nozzle thread has reached the last few turns of the support thread, and vice versa. The anti-loosening device locks the auxiliary nozzle to prevent its movement in the screw-out direction, while allowing relative movement in the screw-in direction.

[0017] The anti-loosening device specifically prevents the auxiliary nozzle from moving relative to the support member in the unscrewing direction when the auxiliary nozzle and support member are in the screw-in end position.

[0018] Preferably, the support thread is an internal thread and the auxiliary nozzle thread is an external thread, wherein the two threads are adapted to engage with each other.

[0019] In a first embodiment, the anti-loosening device includes a resiliently compressible annular component disposed between a support member and an auxiliary nozzle. The annular component is compressed as the auxiliary nozzle thread reaches the last few turns of the support thread, and vice versa. The compressed annular component applies an axial force to the auxiliary nozzle, causing the threads to press against each other. This increased friction resists loosening caused by vibration, shock waves, or other external forces. The compressible annular component is a simple and effective measure to prevent thread loosening.

[0020] Preferably, a first end surface is formed on the radial surface of the support member facing the auxiliary nozzle, and a second end surface is formed on the radial surface of the auxiliary nozzle facing the support member. When the auxiliary nozzle and the support member are in the screw-in end position, the compressible annular member is compressed between the first and second end surfaces.

[0021] In a second embodiment, the anti-loosening device includes at least one spring-loaded pin and a profile arranged such that the pin and the profile move relative to each other when the auxiliary nozzle rotates in the screw-in direction. The pin is spring-loaded against the profile when the auxiliary nozzle thread reaches the last few turns of the support thread, and vice versa. Preferably, a plurality of pins are concentrically arranged and axially positioned relative to the axis of the support member. The pin is preferably located on the support member, and the profile is formed on the surface of the auxiliary nozzle facing the pin.

[0022] The profile preferably comprises a plurality of profile slots, each having a first and a second ramp. The first ramp is specifically configured to lock the pin when it is positioned in one of the slots, preventing the auxiliary nozzle from moving in the outward direction. The first ramp is steeper than the second ramp, allowing the pin to slide on the second ramp when the auxiliary nozzle rotates in the inward direction. Once the pin is locked in the slot, the auxiliary nozzle is securely held in the inward position.

[0023] In another embodiment, the anti-loosening device includes a plurality of radially outwardly extending ratchets formed on the auxiliary nozzle at the tip of the auxiliary nozzle thread, and at least one recess formed on the support member at the base of the support thread. The ratchets are configured to engage in the recess when the auxiliary nozzle thread and the support thread reach their end positions. Preferably, the auxiliary nozzle and the ratchets are integrally formed as a single piece.

[0024] Preferably, the ratchet is a resilient hook component with an inclined leading edge and a locking edge. The leading edge slides on the edge of the recess in the screw-in direction, while the locking edge engages with the edge of the recess to prevent movement in the screw-out direction.

[0025] In another embodiment, the anti-loosening device includes a radially extending annular protrusion formed on a support member and an annular edge and adjacent annular groove formed on an auxiliary nozzle. The annular edge and the protrusion include inclined guide surfaces arranged in an axial direction. During tightening, the annular edge passes over the protrusion, and the protrusion engages in the annular groove when the thread reaches its end portion.

[0026] Preferably, multiple axially extending notches are formed in the annular edge to facilitate deformation during engagement with the annular protrusion.

[0027] The annular edge and groove can be arranged at the top of the auxiliary nozzle thread, with the annular protrusion at the base of the support thread; or the annular edge and groove are located at the base of the auxiliary nozzle thread, and the annular protrusion is located at the top of the support thread.

[0028] To enhance the functionality of the annular edge, multiple axially extending notches are distributed circumferentially along it. These notches divide the annular edge into multiple segments, allowing it to buckle radially inward as the auxiliary nozzle screws into the support component in the screw-in direction. This configuration reduces the force required to push the annular edge against the annular protrusion while maintaining its ability to securely engage with the annular groove once the protrusion crosses the edge. The circumferential distribution of the notches ensures uniform flexibility and consistent mechanical properties throughout the entire periphery of the annular edge.

[0029] The annular protrusion and the inclined guide surface of the annular edge are configured to optimize engagement and locking performance. The guide surface has an inclination angle relative to the axial direction, which is optimized to facilitate smooth engagement during screwing in the screw-in direction. The angle of the guide surface can be in the range of 20° to 70°, preferably in the range of 30° to 60°, more preferably in the range of 40° to 50°, and especially at least approximately 45°.

[0030] On the opposite side of the guide surface, this surface is characterized by a steeper locking angle. This locking angle is configured to resist disengagement in the unscrewing direction, providing a robust locking mechanism to prevent the auxiliary nozzle from unintentionally detaching from the support member. The combination of the tilt angle and the steeper locking angle ensures that the anti-loosening device remains effective even under high mechanical stress (such as during arcing events), thereby maintaining the integrity of the connection between the auxiliary nozzle and the support member. Attached Figure Description

[0031] Features of the various embodiments described herein may be combined with each other where appropriate, provided that such combinations are not mutually exclusive. Further details and features are provided in the drawings, description, and claims. The drawings are as follows: Figure 1 An example of a circuit breaker is shown in a longitudinal section view; Figure 2 A first example of an anti-loosening device is shown in a longitudinal cross-sectional view; Figures 3 to 6 A second example of an anti-loosening device is shown in a longitudinal section and a detailed view; Figure 7 and Figure 8 A third example of an anti-loosening device is shown in longitudinal and cross-sectional views; Figures 9 to 11 A fourth example of an anti-loosening device is shown in longitudinal section and detailed view; and Figures 12 to 14 The fifth example of an anti-loosening device is shown in a longitudinal section and a detailed view. Detailed Implementation

[0032] Figure 1 An example of a medium-voltage or high-voltage circuit breaker 10 is shown. Figure 1 The embodiments shown are merely exemplary; the invention covers all embodiments of medium- or high-voltage circuit breakers, especially those in which the auxiliary nozzle is connected to the support member of the electrode via a threaded connection.

[0033] The circuit breaker 10 includes a first arcing contact 11 and a second arcing contact 12 that are axially movable relative to each other along axis A. The circuit breaker 10 operates between an open position in which the arcing contacts 11 and 12 are separated and a closed position in which the arcing contacts 11 and 12 are in contact.

[0034] As in Figure 1 As shown, the circuit breaker 10 also includes an arc-blowing nozzle 13 positioned between the first arc-initiating contact 11 and the second arc-initiating contact 12. The arc-blowing nozzle 13 includes a middle portion 14 forming a throat, an upstream end portion 15, and a downstream end portion 16. The terms "upstream" and "downstream" refer to the flow direction of the arc control gas.

[0035] The arc control gas can be any type of arc-extinguishing gas. Arc control gases may include sulfur hexafluoride (SF6). Arc control gases may also include carbon dioxide (CO2). Alternatively, the arc control gas may be a mixture comprising heptafluoroisobutyronitrile, carbon dioxide (CO2), and optionally oxygen. For example, it may be a gas consisting of 2 to 15 mol% heptafluoroisobutyronitrile, 60 to 98 mol% carbon dioxide, and 0 to 25 mol% oxygen.

[0036] The first arc initiating contact 11, the second arc initiating contact 12, and the arc blowing nozzle 13 are enclosed in the arc extinguishing chamber 17.

[0037] The first arc-initiating contact 11 is characterized by a contact opening 18 on a first side 19 facing the second arc-initiating contact 12. The first arc-initiating contact 11 is configured to receive the second arc-initiating contact 12 through the contact opening 18 when the circuit breaker 10 is in the closed position.

[0038] The first arc-initiating contact 11 is disposed within a support member 20 on a second side 21 opposite to the second arc-initiating contact 12. On the first side 19, the first arc-initiating contact 11 is disposed within an auxiliary nozzle 22. The auxiliary nozzle 22 includes an auxiliary nozzle opening 23 aligned with the contact opening 18. The auxiliary nozzle 22 is made of a fluorocarbon polymer, such as polytetrafluoroethylene (PTFE).

[0039] The support member 20 and the auxiliary nozzle 22 are connected via a threaded connection 24 including an anti-loosening device 25. The anti-loosening device 25 is configured to prevent the auxiliary nozzle 22 from moving relative to the support member 20 in the screw-out direction 26.

[0040] Figure 2 A detailed longitudinal cross-sectional view of a first embodiment of the anti-loosening device 25 is provided. In this embodiment, the anti-loosening device 25 includes an elastically compressible annular member 27 positioned between the support member 20 and the auxiliary nozzle 22.

[0041] As in Figure 2 As shown, the support member 20 includes a support thread 28, and the auxiliary nozzle 22 includes an auxiliary nozzle thread 29. Both threads have multiple turns. In this embodiment, the support thread 28 is an internal thread, while the auxiliary nozzle thread 29 is an external thread, and the two threads are adapted to engage with each other.

[0042] In the simplest example, the compressible annular component can be an O-ring. Alternatively, the compressible annular component 27 can be a wave spring, a helical compression spring ring, etc.

[0043] exist Figure 2 In the figure, the auxiliary nozzle 22 is shown in the screw-in end position relative to the support member 20. In this position, the compressible annular member 27 is compressed and applies an axial force to the auxiliary nozzle 22. This force causes threads 28 and 29 to press against each other, as indicated by the small arrows in the figure. The increased friction between the auxiliary nozzle thread 29 and the support thread 28 prevents the auxiliary nozzle 22 from moving in the screw-out direction 26.

[0044] The compressible annular component 27 is positioned between a first end surface 30 formed on the radial surface of the support component 20 facing the auxiliary nozzle 22 and a second end surface 31 formed on the radial surface of the auxiliary nozzle 22 facing the support component 20.

[0045] Figure 3 A second embodiment of the anti-loosening device 25 is shown. In this embodiment, the anti-loosening device 25 includes at least one pin 32 and a profile 33, arranged such that the pin 32 and profile 33 move relative to each other when the auxiliary nozzle 22 rotates about axis A in the screw-in direction 34. When the auxiliary nozzle thread 29 reaches the last few turns of the support thread 28, the pin 32 is spring-loaded by the spring member 35 against the profile 33, and vice versa. Figure 3 In the diagram, the second spring loading pin 32 and its corresponding contour 33 are shown in dashed lines. Preferably, multiple spring loading pins 32 are used to improve the angular accuracy of the anti-loosening device 25.

[0046] Profile 33 includes a plurality of profile pockets 36 arranged on a radial surface facing the pin 32. Each profile pocket 36 includes a first ramp 37 and a second ramp 38. The first ramp 37 is steeper than the second ramp 38. This configuration allows the first ramp 37 to lock the pin 32 when it engages with the profile pocket 36, thereby preventing the auxiliary nozzle 22 from moving about axis A in the rotation direction 26 relative to the support member 20.

[0047] Figures 4 to 6 Detailed views of the anti-loosening device 25 are provided, showing the auxiliary nozzle 22 in various angular positions relative to the support member 20.

[0048] exist Figure 4 In the diagram, the spring component 35 is shown in a compressed state because the pin 32 has not yet reached the contour slot 36 of the contour 33. In this state, the auxiliary nozzle 22 rotates in the screw-in direction 34.

[0049] Figure 5 The auxiliary nozzle 22 is shown in a further screw-in position in the screw-in direction 34. In this position, the pin 32 is about to enter the profiled slot 36 and contact the second ramp 38. Since the second ramp 38 is not as steep as the first ramp 37, the pin 32 can slide along it, allowing the auxiliary nozzle 22 to rotate further in the screw-in direction 34 without obstruction.

[0050] Figure 6 An auxiliary nozzle 22 rotating in the rotation direction 26 is depicted. In this state, the pin 32 engages with the first ramp 37 of the profiled slot 36. Due to the steepness of the first ramp 37, the auxiliary nozzle 22 cannot rotate further in the rotation direction 26, effectively locking it in place.

[0051] Figure 7 and Figure 8 A third example of the anti-loosening device 25 of the present invention is shown. In this embodiment, the anti-loosening device 25 includes a plurality of ratchet 39 formed on the auxiliary nozzle 22 at the tip 40 of the auxiliary nozzle thread 29 facing the support member 20. The ratchet 39 project radially outward in a radial direction R. The anti-loosening device 25 also includes at least one recess 41 formed on the support member 20 at the base 53 of the support thread 28. The ratchet 39 and the recess 41 are configured such that when the auxiliary nozzle 22 is in the screw-in end position relative to the support member 20, the ratchet 39 engages in the recess 41.

[0052] The ratchet 39 and the auxiliary nozzle 22 are integrally formed from PTFE. The ratchet 39 is a resilient hook configured to pass over the edge of the recess 41 in the screw-in direction 34 and engage securely in the recess 41 after passing the edge. This engagement prevents the auxiliary nozzle 22 from moving relative to the support member 20 in the screw-out direction 26.

[0053] Figure 8 A cross-sectional view of the anti-loosening device 25 in the third example is provided. In this embodiment, ratchet 39s are evenly distributed around axis A along the periphery of auxiliary nozzle 22, wherein each ratchet 39 is positioned at a constant distance from axis A.

[0054] Each ratchet 39 includes a guide surface 42 and a barbed edge 43. The guide surface 42 is configured to slide on the edge 44 of the recess 41 as the auxiliary nozzle 22 rotates about axis A in the screw-in direction 34. Once the ratchet 39 is in place in the recess 41, the barbed edge 43 follows the guide surface 42 and locks against the edge 44 of the recess 41.

[0055] exist Figure 8 The image shows a ratchet 39 engaging with a recess 41, its barbed edge 43 abutting the edge 44 of the recess 41. This engagement prevents the auxiliary nozzle 22 from moving relative to the support member 20 in the outward direction 26. The ratchet 39 is a flexible protrusion with an inclined leading edge 54 and a locking edge 55. The leading edge 54 is configured to slide on the edge of the recess 41 in the inward direction 34, and the locking edge 55 is configured to securely engage with the recess 41 to prevent the auxiliary nozzle 22 from moving in the outward direction 26.

[0056] Figure 9 , 10 Figures 1 and 11 illustrate a fourth example of an anti-loosening device 25. In this embodiment, the anti-loosening device 25 includes a radially extending annular protrusion 45 formed on the support member 20. The annular protrusion 45 includes a guide surface 46 facing and inclined toward the auxiliary nozzle 22.

[0057] The anti-loosening device 25 also includes an annular edge 47 and an adjacent annular groove 48, both formed on the auxiliary nozzle 22. The annular edge 47 is characterized by a guide surface 49 facing the support member 20. The guide surface 49 of the annular edge 47 is also inclined. The guide surfaces 46 and 49 are configured to slide relative to each other when the auxiliary nozzle 22 is screwed into the support member 20. During this process, the annular edge 47 is pushed radially inward, allowing the annular protrusion 45 to pass over the annular edge 47. Once the annular edge 47 has passed the annular protrusion 45, the annular protrusion 45 is trapped in the annular groove 48, locking the auxiliary nozzle 22 in place when moved in the unscrewing direction 26.

[0058] To facilitate the radial inward pushing of the annular edge 47, the annular edge 47 is divided into multiple clamping segments by a plurality of axially extending notches 50. These notches 50 allow the segments of the annular edge 47 to buckle radially inward as the annular protrusion 45 passes over them.

[0059] Figure 10A detailed view is provided of the anti-loosening device 25 during the process of the annular edge 47 passing over the annular protrusion 45. The tilt angle α of the guide surface 46 of the annular protrusion 45 and the guide surface 49 of the annular edge 47 is at least approximately 45° relative to the angular axis A. The locking angle β of the surface adjacent to the annular edge 47 is at least approximately 90° relative to the angular axis A. Both angles α and β may differ. Figure 10 The example provided is shown in the document.

[0060] Figure 11 The diagram shows the state after the annular protrusion 45 is engaged in the annular groove 48. In this position, the annular protrusion 45 located in the annular groove 48 prevents the auxiliary nozzle 22 from moving in the rotation direction 26.

[0061] Figure 12 , 13 Figures 1 and 14 illustrate a fifth example of the anti-loosening device 25 of the present invention. This example is similar to the fourth example, with the key difference being the arrangement of the components. In the fourth example, the annular edge 47 and the annular groove 48 are positioned at the tip of the auxiliary nozzle thread 29, and the annular protrusion 45 is formed at the base 53 of the support thread 28. In contrast, in the fifth example, the annular edge 47 and the annular groove 48 are arranged at the base 51 of the auxiliary nozzle thread 29, while the annular protrusion 45 is formed at the tip 52 of the support thread 28.

[0062] This invention relates to a medium- or high-voltage circuit breaker 10, comprising a first electric arcing contact 11 and a second electric arcing contact 12 axially movable relative to each other between an open position where arcing contacts 11 and 12 are separated and a closed position where they are in contact. The circuit breaker 10 includes an auxiliary nozzle 22 made of a fluorocarbon polymer or of polyethylene, polyamide, polyimide, polyketone, polyacetal, polysulfone, or polysulfide, connected to a support member 20 via a threaded connection 24. To prevent loosening caused by operational vibrations or shock waves during an arcing event, the threaded connection is equipped with an anti-loosening mechanism. Various embodiments of the anti-loosening device 25 are disclosed, including: a compressible annular member 27 that increases friction between the threads; a spring-loaded pin 32 that interacts with a contoured slot 36; a resilient ratchet 39 that engages with a recess 41; and an annular edge 47 that mates with an annular protrusion 45. These mechanisms ensure that the auxiliary nozzle 22 remains securely attached to the support member 20 in the screw-in position while allowing for easy assembly. The present invention provides a robust and reliable connection between the auxiliary nozzle 22 and the support component 20, enhancing the performance and durability of the circuit breaker 10 under high mechanical and thermal stress conditions.

[0063] List of reference numerals 10. Medium or high voltage circuit breakers 11 First (Electrical) Arc Initiation Contact 12 Second (Electrical) Arc Initiation Contact 13 Arc-blowing nozzle 14. Middle section 15. End portion (upstream) 16. End portion (downstream) 17. Arc-extinguishing chamber 18. Contact opening 19 First side 20 Support components 21 Second side 22 (Dielectric) Auxiliary Nozzle 23 Auxiliary nozzle opening 24 Threaded connection 25 Anti-loosening devices 26. Rotation direction 27. Compressible ring-shaped component 28 Support thread 29 Auxiliary nozzle thread 30 First end surface 31 Second end surface 32 (Spring-loaded) pin 33 Outline 34. Rotation direction 35 Spring components 36. Profiled slotted bag 37. The first slope of the profiled slotted bag 38. The second slope of the profiled groove bag 39. Ratchet 40. Tip of auxiliary nozzle thread 41 recess 42. Guide surface of the ratchet 43. The barbed edge of the ratchet. 44. The edge of the concave portion 45 Annular protrusions 46. ​​Circular protrusions on the guiding surface 47. Circular edge 48 Annular groove 49. Guide surface with annular edge 50 gap 51. Base of auxiliary nozzle thread 52. Top of the support thread 53. Base of the supporting thread 54. Frontier 55 Lock Edge Axial axis G Arc-extinguishing gas flow R radial α Inclination angle β is the locking angle.

Claims

1. A medium-voltage or high-voltage circuit breaker (10), comprising: A first arcing contact (11) and a second arcing contact (12) are axially movable relative to each other between the open position and the closed position of the circuit breaker (10), wherein the arcing contacts (11, 12) are separated from each other in the open position and are in contact with each other in the closed position. The first arc-initiating contact (11) includes a contact opening (18) on a first side (19) facing the second arc-initiating contact (12), and the first arc-initiating contact (11) is configured to receive the second arc-initiating contact (12) within the contact opening (18) when the arc-initiating contacts (11, 12) are in the closed position. The first arc-initiating contact (11) is disposed in a support member (20) on the second side (21) opposite to the second arc-initiating contact (12) and in an auxiliary nozzle (22) on the first side (19) of the first arc-initiating contact (11). The auxiliary nozzle (22) includes an auxiliary nozzle opening (23) aligned with the contact opening (18) and is made of fluorocarbon polymer. The support member (20) and the auxiliary nozzle (22) are connected to each other by a threaded connection (24), the threaded connection including an anti-loosening mechanism (25) configured to prevent the auxiliary nozzle (22) from moving relative to the support member (20) in the unscrewing direction (26).

2. The medium-voltage or high-voltage circuit breaker (10) according to claim 1, wherein, The auxiliary nozzle (22) includes an auxiliary nozzle thread (29) and the support member (20) includes a support thread (28), the auxiliary nozzle thread (29) and the support thread (28) being able to engage with each other.

3. The medium-voltage or high-voltage circuit breaker (10) according to claim 2, wherein, The support thread (28) is an internal thread and the auxiliary nozzle thread (29) is an external thread, and the threads (28, 29) are adapted to each other.

4. The medium-voltage or high-voltage circuit breaker (10) according to any one of the preceding claims, wherein, The anti-loosening device (25) is effective only when the auxiliary nozzle thread (29) reaches the last few turns of the support thread (28), and vice versa.

5. The medium-voltage or high-voltage circuit breaker (10) according to claim 4, wherein, The anti-loosening device (25) includes an elastically compressible annular component (27) disposed between the support member (20) and the auxiliary nozzle (22), wherein the annular component (27) is compressed when the auxiliary nozzle thread (29) reaches the last few turns of the support thread (28), and vice versa.

6. The medium-voltage or high-voltage circuit breaker (10) according to claim 5, wherein, The compressed annular component (27) applies an axial force to the auxiliary nozzle (22), pressing the threads (28, 29) together.

7. The medium-voltage or high-voltage circuit breaker (10) according to any one of the preceding claims, wherein, The anti-loosening device (25) includes: (a) At least one spring-loaded pin (32) configured to engage a profile (33) on the auxiliary nozzle (22) or the support member (20), wherein the pin (32) and the profile (33) move relative to each other when the auxiliary nozzle (22) rotates in the screw-in direction (34); and (b) A plurality of contoured pockets (36) on the contour (33), each having a first ramp (37) configured to lock the pin (32) and prevent the auxiliary nozzle (22) from moving relative to the support member (20) in the rotation direction (26).

8. The medium-voltage or high-voltage circuit breaker (10) according to any one of the preceding claims, wherein, The anti-loosening device (25) includes: (a) A plurality of ratchet wheels (39) formed on the auxiliary nozzle (22) and projecting radially outward from the tip (40) of the auxiliary nozzle thread (29); and (b) At least one recess (41) formed in the support member (20) at the base (53) of the support thread (28), the ratchet (39) being configured to engage in the recess (41) when the auxiliary nozzle thread (29) and / or the support thread (28) reach their end portions.

9. The medium-voltage or high-voltage circuit breaker (10) according to claim 8, wherein, The ratchet (39) is an elastic hook component configured to pass over the edge of the recess (41) in the screw-in direction (34) and engage with the recess (41) after passing the edge, thereby preventing the auxiliary nozzle (22) from moving in the screw-out direction (26).

10. The medium-voltage or high-voltage circuit breaker (10) according to claim 8 or 9, wherein, The ratchet (39) is a flexible protrusion with an inclined leading edge (54) and a locking edge (55), the leading edge (54) being configured to slide on the edge of the recess (41) in the screw-in direction (34), and the locking edge (55) being configured to firmly engage with the recess (41) to prevent the auxiliary nozzle (22) from moving in the screw-out direction (26).

Images