SF6 circuit breaker structure special for CGIS and use method

Abstract

The invention relates to an SF6 circuit breaker structure special for a CGIS and a using method, the SF6 circuit breaker structure comprises an insulating cylinder, a static end metal joint fixedly connected to the front end of the insulating cylinder and a movable end metal joint fixedly connected to the side face of the insulating cylinder, and a movable contact seat support electrically connected with the movable end metal joint is fixedly connected in the insulating cylinder; the movable contact seat support divides the interior of the insulating cylinder into a front chamber and a rear chamber which are closed, the inner side of the static end metal joint is fixedly connected with a static contact assembly, the movable contact seat support is fixedly connected with a piston located in the front chamber, the piston is sleeved with the air cylinder, the pull rod is fixedly connected with the air cylinder, and the pull rod penetrates through the movable contact seat support in a sealed mode. A switch-on and switch-off driving mechanism for driving the pull rod to move back and forth is installed in the rear cavity, one end, close to the static contact assembly, of the air cylinder is fixedly connected with a moving contact pipe communicated with an inner cavity of the air cylinder, and one end, facing the static contact assembly, of the moving contact pipe is provided with a connecting nozzle matched with the static contact assembly. And the blank that the CGIS has no SF6 circuit breaker is filled.

Description

Technical Field

[0001] This invention relates to the field of high-voltage switchgear technology, specifically to a structure and usage method of a CGIS-specific SF6 circuit breaker. Background Technology

[0002] Currently, gas-insulated high-voltage switchgear, abbreviated as CGIS, uses vacuum circuit breakers as its main switching element. However, vacuum circuit breakers often experience current-cutting overvoltage when breaking capacitive loads, which has become a consensus in the industry. SF6 circuit breakers, on the other hand, use gas arc extinguishing, which effectively solves the problem of breaking capacitive loads. SF6 circuit breakers are commonly used in medium and high voltage switchgear.

[0003] CGIS generally uses vacuum circuit breakers, and the arc-extinguishing chamber of the circuit breaker may be solid-sealed, such as patent number CN110994435B, a patent for a gas-insulated switchgear, which uses a solid-sealed pole structure for a cast vacuum arc-extinguishing chamber. Patent number CN105609362B, a solid-sealed insulated vacuum circuit breaker for a gas-insulated switchgear, describes a solid-sealed pole connected to the circuit breaker operating mechanism; this solid-sealed pole is the vacuum arc-extinguishing chamber.

[0004] Alternatively, a support structure design may be used, such as patent number CN103050327B, where the vacuum circuit breaker and medium-voltage gas-insulated switchgear vacuum circuit breaker include a support, operating mechanism, insulating cylinder, arc-extinguishing chamber, and insulating tie rod. Another example is patent number CN214012827U, a bracket-type gas-insulated switchgear circuit breaker, where the support structure includes insulating supports symmetrically arranged on both sides of the conductive component, and the conductive component includes a vacuum arc-extinguishing chamber.

[0005] SF6 circuit breakers have an outdoor porcelain column type structure, such as patent number CN106128844A, which discloses an outdoor AC high-voltage porcelain column type circuit breaker, including a base frame, support, crossbeam, upper porcelain column, and lower porcelain column. Another example is patent number CN105244222A, which discloses a porcelain column type circuit breaker, including an upper terminal block, arc-extinguishing porcelain bushing, stationary contact seat, and supporting porcelain bushing.

[0006] SF6 circuit breakers also have a tank-type structure, such as patent number: CN207602465U, which provides a high-voltage AC sulfur hexafluoride tank-type circuit breaker. The three breaking units of the three phases A, B and C of the circuit breaker are respectively distributed inside the breaking unit shell, such as patent number: CN113593993A, which is an arc-extinguishing chamber and a tank-type circuit breaker.

[0007] In summary, existing CGIS patents primarily focus on vacuum circuit breakers, with diverse insulation supports. Since the vacuum interrupter is a closed vacuum structure, no sealing requirement is needed for the insulation support to meet the requirements. However, existing SF6 circuit breakers are mainly of porcelain column type and tank type, which are large in size and unsuitable for direct placement within the compact CGIS. The reason for this is that gas-operated circuit breakers require sealed high-pressure gas, while CGIS uses a low-pressure strength design, making direct application of the SF6 interrupter impossible. Otherwise, the gas tank would fail due to the high pressure. Therefore, the innovation of this patent lies in finding a feasible solution. This patent innovatively implements a high-pressure interrupter for application within a low-pressure CGIS gas tank, featuring small size, convenient installation, and no alteration to the original design, filling a gap in the industry. Summary of the Invention

[0008] This invention addresses the shortcomings of existing technologies by providing a structure and usage method for a CGIS-specific SF6 circuit breaker.

[0009] This invention is achieved through the following technical solution: providing a CGIS-specific SF circuit breaker structure, including an insulating cylinder, a stationary metal connector fixed to the front end of the insulating cylinder, and a moving metal connector fixed to the side of the insulating cylinder. A moving contact support, electrically connected to the moving metal connector, is fixed inside the insulating cylinder. The moving contact support divides the insulating cylinder into two sealed front and rear chambers. A stationary contact assembly is fixed to the inner side of the stationary metal connector. A piston located in the front chamber is fixed to the moving contact support. The invention also includes a cylinder sleeved on the piston and a pull rod fixed to the cylinder. The pull rod passes through the moving contact support in a sealed manner. A closing / opening drive mechanism for driving the pull rod to move back and forth is installed in the rear chamber. A moving contact tube communicating with the cylinder's inner cavity is fixed to one end of the cylinder near the stationary contact assembly. A connection nozzle adapted to the stationary contact assembly is provided at the end of the moving contact tube facing the stationary contact assembly.

[0010] In this scheme, the insulating cylinder is divided into two sealed front and rear chambers by a moving contact support. Both chambers are filled with SF gas. The overall structure is compact. The opening and closing drive mechanism drives the drive rod to move back and forth, thereby moving the moving contact tube back and forth to realize the opening and closing operation. In the closing state, the moving contact tube is inserted into the stationary contact assembly. When opening, the rod drives the cylinder and the moving contact tube to move backward, which compresses the inner cavity between the cylinder and the piston. The internal gas is ejected through the connecting nozzle at the front end of the moving contact tube to realize the air blowing to extinguish the arc at the front end of the moving contact tube.

[0011] As an optimization, the cylinder has multiple connecting holes at its front end, and the front end of the pull rod passes through the front end of the cylinder and is fixedly connected to it. The connecting holes in this design enable communication between the cylinder and the interior of the moving contact tube.

[0012] As an optimization, the front end face of the pull rod has a central hole, which is a countersunk hole and has a radial side hole at the bottom. In the closed state, the side hole is sealed within the moving contact seat support. During the opening process, when the moving contact tube is completely separated from the stationary contact assembly, the side hole moves out of the moving contact seat support and connects to the rear chamber. In this design, when the pull rod moves backward, it compresses the rear chamber, increasing its internal pressure. When the moving contact tube is completely separated from the stationary contact assembly, the side hole moves out of the moving contact seat support and connects to the rear chamber, allowing the compressed gas in the rear chamber to enter the central hole through the side hole and then be ejected through the front end of the central hole, achieving arc extinguishing by blowing gas. Because the rear chamber is compressed, the gas velocity is high, resulting in a better arc extinguishing effect.

[0013] As an optimization, the stationary contact assembly includes a stationary contact seat fixed to the inner side of the stationary metal connector. The inner ring of the stationary contact seat is fitted with a stationary contact, and the inner ring of the stationary contact is fitted with a stationary arc contact. The inner ring of the stationary contact is adapted to the outer ring of the moving contact tube, and the outer ring of the stationary arc contact is adapted to the inner ring of the moving contact tube. In this design, when the moving contact tube closes, it first contacts the stationary arc contact, then the stationary contact; when opening, it first separates from the stationary contact, then from the stationary arc contact. The arc is located between the moving contact tube and the stationary arc contact. The stationary arc contact is heat-resistant to prevent deformation caused by discharge.

[0014] As an optimization, a support column extends forward from the front end of the moving contact seat support, and the piston is fixed to the front end of the support column. In this design, the support column supports the piston and facilitates the forward and backward movement of the cylinder.

[0015] As an optimization, a support ring seat is fixedly connected inside the insulating cylinder to the moving end metal connector, and the moving contact seat support is fixedly connected to the support ring seat by bolts. The support ring seat in this design enables the moving contact seat support to be detachably installed.

[0016] As an optimization, a fixed sealing plate is fixedly connected to the rear end of the insulating cylinder, and a sealed transmission air box is fixedly connected to the rear end of the fixed sealing plate. The transmission air box is connected to the rear end of the insulating cylinder. The opening and closing drive mechanism includes a main shaft shafted inside the transmission air box. The main shaft is sealed and extends out of the main shaft and is connected to the operating mechanism. A rotating crank arm is fixedly connected to the main shaft. The rotating crank arm is hinged to one end of the insulating pull rod, and the other end of the insulating pull rod is hinged to the pull rod. In this design, the operating mechanism drives the main shaft to rotate, thereby driving the pull rod to move back and forth through the main shaft and the rotating crank arm. Since the main shaft seal passes through the transmission air box, and the transmission air box and the rear chamber are a sealed structure connected, the sealing effect on the front chamber is improved. Even if the front chamber leaks, it will leak into the rear chamber. The overall sealing effect is good.

[0017] As an optimization, the transmission air box is equipped with an interface, which is connected to a pressure gauge via an air pipe. The pressure gauge in this design is used to detect the air pressure inside the transmission air box, facilitating observation and monitoring of internal pressure changes.

[0018] As an optimization, both the outer side of the stationary metal connector and the outer side of the moving metal connector are provided with threaded countersunk holes. These threaded countersunk holes in this design are used to connect to the electrical wire.

[0019] A method for using a CGIS-specific SF6 circuit breaker structure includes the following steps: a. The opening and closing operation is achieved by driving the drive rod to move back and forth through the opening and closing drive mechanism, thereby driving the moving contact tube to move back and forth. b. When the circuit is closed, the moving contact tube is inserted into the stationary contact assembly. When the circuit is open, the pull rod drives the cylinder and the moving contact tube to move backward, which compresses the inner cavity between the cylinder and the piston. The internal gas is ejected through the connecting nozzle at the front end of the moving contact tube to extinguish the arc by blowing air at the front end of the moving contact tube. c. When the pull rod moves backward, it will compress the rear chamber, increasing its internal pressure. When the moving contact tube and the stationary contact assembly are completely separated, the side hole moves out of the moving contact seat support and connects with the rear chamber, thereby allowing the compressed gas in the rear chamber to enter the central hole through the side hole, and then be ejected through the front end of the central hole to achieve air blowing to extinguish the arc.

[0020] The beneficial effects of this invention are as follows: Firstly, this structure overcomes the limitation that traditional SF6 circuit breakers, due to their overall high-pressure design, cannot be directly applied to low-voltage CGIS gas boxes. It creatively modularizes and seals the high-pressure arc-extinguishing chamber, integrating it within a low-pressure sealed enclosure, achieving compatibility between high-pressure arc extinguishing and low-voltage cabinet environments. This allows the excellent capacitive load breaking performance and reliable arc-extinguishing capability of SF6 circuit breakers to be applied in compact CGIS, filling a technological gap in the industry in this field.

[0021] Secondly, this design offers significant advantages in miniaturization and modularity. By integrating the arc-extinguishing chamber, cylinder, piston, and drive mechanism into a single insulating cylinder assembly, an independent sealing functional unit is formed, resulting in a compact overall structure and convenient installation. This retains the excellent arc-extinguishing performance of SF6 circuit breakers while significantly reducing equipment size, meeting the requirements of CGIS for miniaturization and high reliability, and without altering the original low-pressure gas box design and manufacturing process of the gas-insulated switchgear.

[0022] Regarding arc-extinguishing performance, this patent features a unique dual-air-path arc-extinguishing mechanism. In the initial opening phase, the piston compresses the gas in the front chamber, forming the first airflow to extinguish the arc through the nozzle at the front end of the moving contact tube. When the moving and stationary contacts are completely separated, the side hole on the pull rod connects to the rear chamber, and the compressed high-pressure gas in the rear chamber is ejected forward through the central hole, forming a stronger and more concentrated second high-speed airflow. This enhances the arc-extinguishing intensity and effectiveness at critical breaking moments, effectively ensuring the reliability of capacitive current interruption.

[0023] Furthermore, this structure offers excellent engineering applicability and economic efficiency. It inherits the mature insulation support and installation methods of vacuum circuit breakers in CGIS, facilitating manufacturing and on-site maintenance. By sealing high-pressure gas within an independent arc-extinguishing unit, it reduces the mechanical strength requirements and manufacturing costs of the entire gas box, providing CGIS with a high-performance, highly reliable, and low-cost new circuit breaker solution with significant promotional value and application prospects. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the present invention in the closed state; Figure 2 This is a schematic diagram of the circuit breaker tripping process of the present invention; Figure 3 This is a schematic diagram of the structure of the present invention in the open state; Figure 4 This is a partially enlarged view of the closed state of the present invention; As shown in the figure: 1. Insulating cylinder; 2. Stationary metal connector; 3. Stationary contact seat; 4. Stationary contact; 5. Stationary arc contact; 6. Moving metal connector; 7. Support ring seat; 8. Moving contact seat support; 9. Pull rod; 10. Cylinder; 11. Insulating pull rod; 12. Rotating crank arm; 13. Main shaft; 14. Transmission air box; 15. Fixed sealing plate; 16. Interface; 17. Air pipe; 18. Pressure gauge; 19. Piston; 20. Center hole; 21. Side hole; 22. End plate; 23. Connecting hole; 24. Moving contact tube. Detailed Implementation

[0025] To clearly illustrate the technical features of this solution, the following detailed implementation method will be used to explain the solution.

[0026] like Figures 1-4 As shown, a CGIS-specific SF6 circuit breaker structure of the present invention includes an insulating cylinder 1, a stationary metal connector 2 fixed to the front end of the insulating cylinder 1, and a moving metal connector 6 fixed to the side of the insulating cylinder 1. The insulating cylinder 1 is a long strip-shaped cylinder extending from front to back. The rear end of the insulating cylinder 1 is open, and a fixing plate 15 is fixed to the rear end opening of the insulating cylinder 1. A sealed transmission gas box 14 is fixed to the rear end of the fixing plate 15. The transmission gas box 14 is connected to the rear end of the insulating cylinder 1 through a through hole. The entire insulating cylinder 1 and the transmission gas box 14 form a sealed space, which is filled with high-pressure SF6 gas.

[0027] The transmission air box 14 is provided with an interface 16, which is connected to a pressure gauge 18 through an air pipe 17 for detecting the air pressure inside the transmission air box, so as to facilitate observation and monitoring of internal air pressure changes.

[0028] The stationary metal connector 2 is embedded in the front end of the insulating cylinder 1, and the moving metal connector 6 is embedded in the side of the insulating cylinder 1 at the middle rear position. Both the outer side of the stationary metal connector 2 and the outer side of the moving metal connector 6 are provided with threaded countersunk holes for connecting to external wires or terminal blocks.

[0029] The insulating cylinder 1 is internally fixed with a movable contact support 8 that is electrically connected to the moving end metal connector 6. Specifically, the insulating cylinder 1 is internally fixed with a support ring seat 7 that is also fixed to the moving end metal connector 6. The movable contact support 8 is fixed to the support ring seat 7 by bolts. The movable contact support 8 divides the insulating cylinder 1 into two sealed front chambers and a rear chamber, with the stationary end metal connector 2 located at the front end of the front chamber.

[0030] The front end of the movable contact seat support 8 extends forward with a support column, and the front end of the support column is fixedly connected to a piston 19. The piston 19 is located in the front chamber, and the diameter of the support column is smaller than the diameter of the piston 19.

[0031] It also includes a cylinder 10 fitted onto the piston 19 and a pull rod 9 fixedly connected to the cylinder 10. The pull rod 9 passes through the movable contact seat support 8 in a sealed manner, and the front end of the cylinder 10 is closed, thereby forming a piston cavity in front of the piston 19. The rear end of the cylinder 10 is open.

[0032] The cylinder 10 is fixedly connected to a moving contact tube 24, which communicates with the inner cavity of the cylinder 10, at one end near the stationary contact assembly. The moving contact tube 24 is a variable diameter tube, with its diameter decreasing in a stepped manner from back to front. The end of the moving contact tube 24 facing the stationary contact assembly is provided with a connecting nozzle adapted to the stationary contact assembly. The connecting nozzle is used to perform opening and closing operations with the stationary contact assembly, and to extinguish the arc by blowing air during opening.

[0033] In order to achieve the connection between the cylinder 10 and the connecting nozzle, a plurality of connecting holes 23 are opened at the front end of the cylinder 10. The plurality of connecting holes 23 are evenly distributed around the center of the cylinder 10. The front end of the pull rod 9 passes through the front end of the cylinder 10 and is fixedly connected to the cylinder 10.

[0034] A stationary contact assembly is fixedly connected to the inner side of the stationary metal connector 2. The stationary contact assembly includes a stationary contact seat 30 fixedly connected to the inner side of the stationary metal connector 2. A stationary contact 4 is installed in the inner ring of the stationary contact seat 30. A stationary arc contact 5 is installed in the inner ring of the stationary contact 4. The inner ring of the stationary contact 4 is adapted to the outer ring of the moving contact tube 24. The outer ring of the stationary arc contact 5 is adapted to the inner ring of the moving contact tube 24.

[0035] The rear chamber is equipped with a brake opening and closing drive mechanism that drives the pull rod 9 to move back and forth. The brake opening and closing drive mechanism includes a main shaft 13 that is shaft-connected to the transmission air box 14. The main shaft 13 is sealed and passes through the main shaft 13 and is connected to the operating mechanism. A rotating crank arm 12 is fixedly connected to the main shaft 13. The rotating crank arm 12 is located in the transmission air box 14. The rotating crank arm 12 is hinged to one end of the insulating pull rod 11, and the other end of the insulating pull rod 11 is hinged to the pull rod 9.

[0036] like Figure 4 As shown, the front end face of the pull rod 9 has a central hole 20, which is a countersunk hole and has a radial side hole 21 connected to its bottom. The side hole 21 is connected to the outer ring of the pull rod 9.

[0037] When the circuit is closed, the side hole 21 is sealed inside the moving contact support 8. During the opening process, when the moving contact tube 24 is completely separated from the stationary contact assembly, the side hole 21 moves out of the moving contact support 8 and connects with the rear chamber. Since the pull rod 9 moves in the direction of the rear chamber when the circuit is closed, the space of the rear chamber is compressed, which increases the internal pressure. When the side hole 21 moves out of the moving contact support 8 and connects with the rear chamber, the air with increased pressure enters the central hole 20 through the side hole 21, and then sprays forward through the front end of the central hole 20 to the moving contact tube 24.

[0038] A method for using a CGIS-specific SF6 circuit breaker structure includes the following steps: a. The opening and closing mechanism drives the drive rod 9 to move back and forth, thereby driving the moving contact tube 24 to move back and forth to achieve the opening and closing operation; b. When the circuit is closed, the moving contact tube 24 is inserted into the stationary contact assembly. When the circuit is open, the pull rod 9 drives the cylinder 10 and the moving contact tube 24 to move backward, which compresses the inner cavity between the cylinder 10 and the piston 19. The internal gas is ejected through the connecting nozzle at the front end of the moving contact tube 24 to extinguish the arc by blowing air at the front end of the moving contact tube 24. c. When the pull rod 9 moves backward, it will compress the rear chamber and increase its internal pressure. When the moving contact tube 24 is completely separated from the stationary contact assembly, the side hole 21 moves out of the moving contact support 8 and connects with the rear chamber, so that the compressed gas in the rear chamber enters the central hole 20 through the side hole 21 and is ejected through the front end of the central hole 20 to achieve air blowing to extinguish the arc.

[0039] Of course, the above description is not limited to the examples above. Technical features not described in this invention can be implemented by or using existing technology, and will not be repeated here. The above embodiments and drawings are only used to illustrate the technical solutions of this invention and are not intended to limit this invention. This invention has been described in detail with reference to preferred embodiments. Those skilled in the art should understand that any changes, modifications, additions or substitutions made by those skilled in the art within the scope of this invention do not depart from the spirit of this invention and should also fall within the scope of protection of the claims of this invention.

Claims

1. A structure for a CGIS-specific SF6 circuit breaker, characterized in that: Includes an insulating cylinder (1), a stationary metal connector (2) fixed to the front end of the insulating cylinder (1), and a moving metal connector (6) fixed to the side of the insulating cylinder (1). A moving contact support (8) electrically connected to the moving metal connector (6) is fixed inside the insulating cylinder (1). The moving contact support (8) divides the insulating cylinder (1) into two sealed front and rear chambers. A stationary contact assembly is fixed to the inner side of the stationary metal connector (2), and a piston located in the front chamber is fixed to the moving contact support (8). 19), also includes a cylinder (10) sleeved on the piston (19) and a pull rod (9) fixedly connected to the cylinder (10). The pull rod (9) passes through the moving contact support (8) in a sealed manner. The rear chamber is equipped with a gate opening and closing drive mechanism that drives the pull rod (9) to move back and forth. The cylinder (10) is fixedly connected to a moving contact tube (24) that communicates with the inner cavity of the cylinder (10) at one end near the stationary contact assembly. The moving contact tube (24) is provided with a connection nozzle adapted to the stationary contact assembly at one end facing the stationary contact assembly.

2. The structure of a CGIS-specific SF6 circuit breaker according to claim 1, characterized in that: The cylinder (10) has multiple connecting holes (23) at its front end, and the front end of the pull rod (9) passes through the front end of the cylinder (10) and is fixedly connected to the cylinder (10).

3. The structure of a CGIS-specific SF6 circuit breaker according to claim 2, characterized in that: The front end face of the pull rod (9) has a central hole (20), which is a countersunk hole and has a radial side hole (21) at the bottom. When the circuit is closed, the side hole (21) is sealed inside the moving contact support (8). During the circuit opening process, when the moving contact tube (24) is completely separated from the stationary contact assembly, the side hole (21) moves out of the moving contact support (8) and connects with the rear chamber.

4. The structure of a CGIS-specific SF6 circuit breaker according to claim 1, characterized in that: The stationary contact assembly includes a stationary contact seat (30) fixed to the inside of the stationary end metal connector (2). The inner ring of the stationary contact seat (30) is equipped with a stationary contact (4), and the inner ring of the stationary contact (4) is equipped with a stationary arc contact (5). The inner ring of the stationary contact (4) is adapted to the outer ring of the moving contact tube (24), and the outer ring of the stationary arc contact (5) is adapted to the inner ring of the moving contact tube (24).

5. The structure of a CGIS-specific SF6 circuit breaker according to claim 1, characterized in that: The front end of the movable contact seat support (8) extends forward with a support column, and the piston (19) is fixed to the front end of the support column.

6. The structure of a CGIS-specific SF6 circuit breaker according to claim 1, characterized in that: The insulating cylinder (1) is fixedly connected to a support ring seat (7) which is fixedly connected to the moving end metal connector (6), and the moving contact seat support (8) is fixedly connected to the support ring seat (7) by bolts.

7. The structure of a CGIS-specific SF6 circuit breaker according to claim 1, characterized in that: The rear end of the insulating cylinder (1) is fixedly connected to a fixed sealing plate (15), and the rear end of the fixed sealing plate (15) is fixedly connected to a sealed transmission air box (14). The transmission air box (14) is connected to the rear end of the insulating cylinder (1). The opening and closing drive mechanism includes a main shaft (13) shafted in the transmission air box (14). The main shaft (13) is sealed through the main shaft (13) and connected to the operating mechanism. A rotating crank arm (12) is fixedly connected to the main shaft (13). The rotating crank arm (12) is hinged to one end of the insulating pull rod (11), and the other end of the insulating pull rod (11) is hinged to the pull rod (9).

8. The structure of a CGIS-specific SF6 circuit breaker according to claim 7, characterized in that: The transmission air box (14) is provided with an interface (16), which is connected to the air pressure gauge (18) through an air pipe (17).

9. The structure of a CGIS-specific SF6 circuit breaker according to claim 1, characterized in that: Both the outer side of the stationary metal connector (2) and the outer side of the moving metal connector (6) have threaded countersunk holes.

10. A method of using the CGIS-specific SF6 circuit breaker structure as described in claim 3, characterized in that, Includes the following steps: a. The opening and closing mechanism drives the drive rod (9) to move back and forth, thereby driving the moving contact tube (24) to move back and forth to realize the opening and closing operation; b. When the circuit is closed, the moving contact tube (24) is inserted into the stationary contact assembly. When the circuit is open, the pull rod (9) drives the cylinder (10) and the moving contact tube (24) to move backward, which compresses the inner cavity between the cylinder (10) and the piston (19). The internal gas is ejected through the connecting nozzle at the front end of the moving contact tube (24) to extinguish the arc by blowing air at the front end of the moving contact tube (24). c. When the pull rod (9) moves backward, it will compress the rear chamber and increase its internal pressure. When the moving contact tube (24) is completely separated from the stationary contact assembly, the side hole (21) moves out of the moving contact support (8) and connects with the rear chamber, so that the compressed gas in the rear chamber enters the central hole (20) through the side hole (21) and is ejected through the front end of the central hole (20) to realize the blowing arc extinguishing.

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