Normal-pressure sealed air-insulated switch cabinet

Abstract

The utility model relates to the technical field of electrical switch equipment, in particular to a normal-pressure sealed air-insulated switch cabinet. The normal pressure sealing air insulation switch cabinet comprises a cabinet body, the cabinet body is provided with a ventilation interface, the ventilation interface is provided with an air valve, the air valve comprises a valve body and a valve core, an inner cavity of the valve body is provided with a valve seat in sealing fit with the valve core, and the valve body or the cabinet body is provided with an air filter installation structure. A pushing part for pushing the valve core is arranged at the air outlet end, allowing filtered air to flow into the cabinet body, of the air filter; the air valve has an open state in which the valve core and the valve seat are in seal fit to communicate the space in the cabinet body with the air outlet end under the pushing of the pushing part, and a closed state in which the valve core and the valve seat are in seal fit to isolate the space in the cabinet body from the external atmosphere when the pushing part is separated from the valve core, and the air valve is closed when the air filter is replaced; the air in the external atmosphere cannot enter the cabinet body, so that the air is prevented from directly entering the cabinet body to influence the gas insulation performance of the switch cabinet.

Description

Technical Field

[0001] This utility model relates to the field of electrical switchgear technology, specifically to a normal pressure sealed air-insulated switchgear. Background Technology

[0002] Ring main units (RNBs) are a type of switchgear and serve as crucial switching equipment for ring network power supply and terminal power supply in power distribution networks. RNBs typically employ gas insulation, with sulfur hexafluoride (SF6) gas insulation being the most widely used. SF6 gas is chemically very stable, possessing excellent insulation and arc-quenching properties, and is widely used in power equipment. However, SF6 gas has a strong destructive effect on the ozone layer and produces highly toxic substances under high-temperature electric arc conditions, posing a significant environmental hazard. Therefore, an increasing number of switchgear units utilize environmentally friendly gas insulation, including RNBs that use dry air at atmospheric pressure as the insulating medium. Dry air is a purely natural gas insulating material, free of toxic arc decomposition products, and has no adverse environmental impact, making it a green and environmentally friendly option.

[0003] For switchgear using dry air at atmospheric pressure as the insulating medium, the temperature inside the switchgear differs from the outside temperature. To balance the pressure difference, vents are typically installed on the switchgear cabinet to allow air circulation. However, ambient air contains dust particles and moisture, making it unsuitable for direct use in gas insulation. It must undergo drying and cleaning processes to meet insulation requirements. Therefore, air filters are installed at the vents. Outside air passes through these filters to remove dust and moisture before entering the internal air chambers of the switchgear cabinet.

[0004] During long-term operation of the switch, the air filter will fail due to blockage and other factors after a period of use. Therefore, the air filter needs to be replaced regularly. When replacing the air filter, the air filter is removed from the cabinet. At this time, the air in the outside atmosphere will directly enter the cabinet through the vent on the cabinet. The air is unfiltered and may affect the gas insulation performance of the switch cabinet. Utility Model Content

[0005] The purpose of this utility model is to provide a normal pressure sealed air-insulated switchgear to solve the problem that the insulation performance of the current normal pressure sealed air-insulated switchgear is easily affected by the direct entry of outside air into the cabinet when the air filter is replaced.

[0006] The technical solution of this utility model for a normal pressure sealed air-insulated switchgear is as follows:

[0007] An atmospheric pressure sealed air-insulated switchgear includes a cabinet with a vent interface. An air valve is installed at the vent interface. The air valve includes a valve body and a valve core. The valve body has a valve seat for sealing with the valve core. The valve body or the cabinet has an installation structure for installing an air filter. The air filter has a pusher for pushing the valve core at its outlet end, where filtered air flows into the cabinet. The air valve has an open state where the valve core and valve seat are released from sealing when pushed by the pusher to connect the internal space of the cabinet with the outlet end, and a closed state where the valve core and valve seat are sealed together when the pusher is disengaged from the valve core to isolate the internal space of the cabinet from the outside atmosphere.

[0008] Beneficial Effects: This utility model innovatively provides a normal-pressure sealed air-insulated switchgear that prevents dust- and moisture-containing air from entering the cabinet when replacing the air filter. By installing an air valve at the cabinet's ventilation interface, the opening and closing of the air valve is linked to the installation and removal of the air filter. During air filter installation, the pusher at the air filter's outlet pushes the valve core, disengaging the valve core from the valve seat and opening the air valve. The cabinet's internal space connects to the air filter through the air valve's internal space. Outside air, filtered by the air filter, enters the cabinet through the open air valve. The air inside the cabinet circulates with the outside air through the open air valve and air filter, ensuring pressure balance inside and outside the cabinet during normal operation. During air filter replacement, when the air filter is removed from the cabinet, the pusher at the air filter's outlet disengages from the valve core, allowing the valve core to return to its sealed position with the valve seat. At this point, the air valve closes, preventing outside air from entering the cabinet and thus avoiding direct air entry that could affect the switchgear's gas insulation performance.

[0009] Furthermore, the valve core is provided with an outer ring platform and an extension section provided on the side of the outer ring platform near the outlet end. The valve body cavity is provided with an inner ring platform for cooperating with the outer ring platform. The inner ring platform constitutes a valve seat. The end of the extension section passes through the inner ring platform so that the pushing part can push and contact it.

[0010] Furthermore, the extension section is provided with an air passage, which has an outer channel opening for corresponding communication with the air outlet end, and an inner channel opening located on the side of the inner ring platform opposite to the air outlet end when the air valve is in the open state.

[0011] Furthermore, the air passage includes an axial blind hole extending along the valve core axis and a radial through hole provided on the wall of the axial blind hole. The opening of the axial blind hole constitutes the outer passage opening of the air passage, and the opening of the radial through hole located on the outer wall of the valve core constitutes the inner passage opening of the air passage.

[0012] Furthermore, a valve core sealing ring is provided on the side of the outer ring platform near the extension section, and a valve seat mating surface is provided on the inner ring platform for cooperating with the valve core sealing ring. The outer diameter of the extension section is adapted to the inner diameter of the inner ring platform, and a valve body sealing ring is provided on the inner wall of the inner ring platform that abuts against the outer peripheral surface of the extension section. When the air valve is in the open state, the inner channel opening is located on the side of the valve body sealing ring away from the end of the extension section, and when the air valve is in the closed state, the inner channel opening is located on the side of the valve body sealing ring near the end of the extension section.

[0013] Furthermore, the valve body has an outer end protruding from the outer wall of the cabinet, and the mounting structure for installing the air filter is located at the outer end of the valve body.

[0014] Furthermore, the valve body has an internal thread at its outer end, which forms a mounting structure for installing an air filter so that the air filter is threadedly connected to the valve body.

[0015] Furthermore, the valve body is provided with a limiting surface for engaging with the outlet end.

[0016] Furthermore, the valve seat is provided with a conical structure, which forms a valve seat mating surface for sealing and engaging with the sealing ring on the valve core.

[0017] Furthermore, the air filter includes a housing and two clean modules and a drying module disposed within the housing, with the drying module positioned between the two clean modules in the airflow direction. Attached Figure Description

[0018] Figure 1 This is a structural schematic diagram of an embodiment of the atmospheric pressure sealed air-insulated switchgear of this utility model;

[0019] Figure 2 for Figure 1 A schematic diagram showing the air valve in the open position;

[0020] Figure 3 for Figure 1 A schematic diagram showing the air valve in the closed state;

[0021] Figure 4 for Figure 2 A schematic diagram of the valve body in the diagram;

[0022] Figure 5 for Figure 2 A schematic diagram of the valve core structure;

[0023] Figure 6 for Figure 1 A schematic diagram of the structure of the air filter in the diagram;

[0024] Figure 7 for Figure 6A schematic diagram of the main housing of the air filter.

[0025] In the diagram: 1. Cabinet;

[0026] 2. Air valve; 21. Valve body; 211. Inner ring platform; 22. Valve core; 221. Outer ring platform; 222. Air passage; 23. Spring; 24. Valve core sealing ring; 25. Valve body sealing ring; 26. Installation sealing ring; 27. Fixing nut;

[0027] 3. Air filter; 31. Air outlet; 32. Air inlet; 33. Main housing; 34. End cap; 35. Drying module; 36. Cleaning module. Detailed Implementation

[0028] This utility model of an atmospheric pressure sealed air-insulated switchgear uses an air valve on the cabinet and links the opening and closing of the air valve with the installation and removal of the air filter. When the air filter is installed, the air valve is open, and when the air filter is removed, the air valve is closed, so as to prevent dusty and moist air from the outside atmosphere from entering the cabinet and affecting the insulation performance when the air filter is replaced.

[0029] An embodiment of the atmospheric pressure sealed air-insulated switchgear of this utility model:

[0030] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5As shown, the atmospheric pressure sealed air-insulated switchgear includes a cabinet 1. The cabinet 1 is provided with a ventilation port, and a valve 2 is installed on the ventilation port. The valve 2 includes a valve body 21 and a valve core 22. The inner cavity of the valve body 21 is provided with a valve seat for sealing with the valve core 22. The valve body 21 is provided with an installation structure for installing an air filter 3. The air filter 3 has an outlet end 31 for filtering air to flow into the cabinet 1. The outlet end 31 is provided with a pushing part for pushing the valve core 22. The valve 2 has an open state in which the valve core 22 is released from the valve seat under the pushing part of the outlet end 31 to connect the space inside the cabinet 1 with the outlet end 31, and a closed state in which the valve core 22 is sealed with the valve seat when the pushing part of the outlet end 31 is disengaged to isolate the space inside the cabinet 1 from the outside atmosphere. The opening and closing of the air valve 2 is linked to the installation and removal of the air filter 3. When installing the air filter 3, the pusher of the air outlet 31 of the air filter 3 pushes the valve core 22, causing the valve core 22 to disengage from the valve seat. The air valve 2 opens, and the space inside the cabinet 1 is connected to the air filter 3 through the internal space of the air valve 2. After being filtered by the air filter 3, outside air enters the cabinet 1 through the open air valve 2. The air inside the cabinet 1 can circulate with the outside air through the open air valve 2 and the air filter 3, ensuring the air pressure balance inside and outside the cabinet 1 during normal operation of the switchgear. During the replacement of the air filter 3, when the air filter 3 is removed from the cabinet 1, the pusher of the air outlet 31 of the air filter 3 disengages from the valve core 22, and the valve core 22 can return to the state of sealing with the valve seat. At this time, the air valve 2 closes, and outside air cannot enter the cabinet 1. This prevents dusty and watery air from entering the cabinet 1 when replacing the air filter 3, thus preventing air from directly entering the cabinet 1 and affecting the gas insulation performance of the switchgear.

[0031] The cabinet 1 in the diagram is simplified. The vent on cabinet 1 is a through-hole structure, used to install air valve 2. Air circulation between the inside and outside is achieved through air valve 2 on the side wall of cabinet 1. The valve body 21 of air valve 2 passes through the vent and is sealed and fixed to cabinet 1. The valve body 21 of air valve 2 has an inner end extending into cabinet 1 and an outer end protruding from the outer wall of cabinet 1. The portion of valve body 21 located outside cabinet 1 has a stepped surface with a sealing ring that seals against the outer wall of cabinet 1. The portion of valve body 21 located inside cabinet 1 is threadedly connected to a fixing nut 27. Tightening the fixing nut 27 fixes valve body 21 to cabinet 1 and compresses the sealing ring to form a seal. The mounting structure for installing air filter 3 is located at the outer end of valve body 21, which helps save internal space in cabinet 1. The valve body 21 has an internal thread at its outer end, which forms an installation structure for mounting the air filter 3. The air filter 3's outlet end 31 has a corresponding external thread, allowing the air filter 3 to be threadedly connected to the valve body 21. This design is simple and provides a stable connection. In other embodiments, a threaded connecting sleeve can be fixed to the portion of the cabinet exterior wall surrounding the vent, instead of having a portion on the valve body for threaded connection of the air filter. The air filter's outlet end is threaded into the threaded connecting sleeve on the cabinet, ensuring that the air filter's outlet end pushes against the valve core. In other embodiments, the air valve can be completely located inside the cabinet, fixed to the inner wall of the cabinet, and not protruding from the outer wall of the cabinet. The air filter's outlet end passes through the vent and connects to the valve body of the air valve. In other embodiments, a locking buckle or quick connector can be used to connect the air filter to the air valve.

[0032] The valve body 21 has an axially continuous inner cavity. The axial direction of the air valve 2 is consistent with the inner and outer directions of the cabinet 1. The valve core 22 is coaxially arranged with the valve body 21. The valve core 22 has an outer ring platform 221 and an extension section near the outlet end 31 of the outer ring platform 221. The inner cavity of the valve body 21 has an inner ring platform 211 for cooperating with the outer ring platform 221. The inner ring platform 211 forms a valve seat. The end of the extension section of the valve core 22 passes through the inner ring platform 211 so that the pushing part of the outlet end 31 of the air filter 3 can push and contact it. The pushing part of the outlet end 31 is its end face. The end face of the outlet end 31 can push the end face of the extension section of the valve core 22, causing the valve core 22 to move inward toward the cabinet 1. The pushing fit is formed by the part of the valve core 22 that protrudes from the valve seat, which is simple in structure and easy to manufacture. In other embodiments, the valve core may not have a portion passing through the valve seat, but instead has a push cantilever facing the valve seat on the end face of the air outlet. When installing the air filter, the push cantilever passes through the valve seat and pushes the valve core to move, causing the valve core to leave the valve seat and open the air valve.

[0033] The outer ring platform 221 is located in the middle of the valve core 22 in the axial direction. The part of the valve core 22 located on one side of the outer ring platform 221 forms an extension section that passes through the inner ring platform 211. The part located on the other side of the outer ring platform 221 is fitted with a spring 23. One end of the spring 23 abuts against the outer ring platform 221, and the other end abuts against the retaining ring provided at the inner end of the valve body 21. The spring 23 is a compression spring that applies a reset force to the valve core 22, so that the valve core 22 maintains the tendency to move from the outer ring platform 221 to the inner ring platform 211 of the valve body 21. After the air filter 3 is removed, the valve core 22 is reset under the action of the spring 23, and the valve core 22 forms a sealing fit with the valve seat.

[0034] The inner ring platform 211 is located in the middle of the valve body 21 along its axial direction. The inner cavity of the valve body 21 includes spaces on both sides of the inner ring platform 211 along its axial direction. A spring 23 is installed in the space facing inwards from the cabinet 1 to allow the outer ring platform 221 to move, while the space facing outwards from the cabinet 1 provides a threaded connection for the air outlet 31. The inner ring platform 211 has a conical structure on its edge near the outer ring platform 221. This conical structure forms a valve seat mating surface for sealing with the sealing ring on the valve core 22. The sealing ring on the valve core 22 is a valve core sealing ring 24, which is installed on the side of the outer ring platform 221 near the extension section. A sealing groove is provided at the junction of the outer ring platform 221 and the extension section, and the valve core sealing ring 24 is installed in the corresponding sealing groove. When the valve core 22 and the valve seat are sealingly mated, the valve core sealing ring 24 is pressed against the conical surface of the valve seat. Under the action of the spring 23, a sealing state is maintained. The sealing is formed by the conical surface mating with the sealing ring, which is beneficial for reliable sealing. In other embodiments, the side of the inner ring platform closest to the outer ring platform can be made into a plane. Accordingly, the valve core is not provided with a sealing groove, and the valve core sealing ring is formed by the cooperation of the outer ring platform and the inner ring platform.

[0035] A sealing groove is provided at the junction of the inner ring platform 211 and the cavity wall of the valve body 21 facing outwards from the cabinet 1. A sealing ring 26 is installed in this sealing groove. The outer edge of the air outlet end 31 of the air filter 3 has a conical surface. When the air filter 3 is installed on the valve body 21, the conical surface of the air outlet end 31 presses against the sealing ring 26 to form a sealing fit, ensuring that the filtered air flows smoothly into the air valve 2. The side of the inner ring platform 211 facing outwards from the cabinet 1 forms a limiting surface on the valve body 21 for stopping the air outlet end 31. After the air filter 3 is installed, the end face of the air outlet end 31 abuts against the inner ring platform 211, facilitating confirmation of proper installation. In other embodiments, the valve body may not have a limiting surface; after the air filter is installed, the inner ring platform and the air outlet end are spaced apart, and only the threads need to be tightened.

[0036] The extension of the valve core 22, which passes through the inner ring platform 211 of the valve body 21, is provided with an air passage 222. The air passage 222 has an outer channel opening for corresponding communication with the air outlet 31, and an inner channel opening located on the side of the inner ring platform 211 opposite to the air outlet 31 when the air valve 2 is in the open state. After the air filter 3 is installed in place, the outer channel opening of the air passage 222 is correspondingly connected to the through hole of the air outlet 31 of the air filter 3. The valve core 22 moves towards the inside of the cabinet 1 under the push of the air outlet 31, and the valve core 22 disengages from the valve seat. The inner channel opening of the air passage 222 moves to the side of the inner ring platform 211 facing the inside of the cabinet 1. The inner channel opening of the air passage 222 is connected to the space of the inner cavity of the valve body 21 facing the inside of the cabinet 1, so that air enters the cabinet 1 through the air passage 222. The use of the separately provided air passage 222 for air circulation is beneficial to improving the circulation capacity. In other embodiments, a separate air passage may not be required; instead, the radial gap between the valve core and the inner annular platform of the valve body can be used for air circulation.

[0037] The air passage 222 includes an axial blind hole extending along the axial direction of the valve core 22 and a radial through hole provided on the wall of the axial blind hole. The opening of the axial blind hole faces the outer side of the cabinet 1 and forms the outer channel opening of the air passage 222. The opening of the radial through hole located on the outer wall of the valve core 22 forms the inner channel opening of the air passage 222. The air passage 222 is formed by the axial blind hole and the radial through hole, which is convenient for processing. In other embodiments, an oblique hole can also be opened on the valve core, with the axis of the oblique hole forming an angle with the axis of the valve core, and the air passage can be formed by the oblique hole.

[0038] The outer diameter of the extension section of the valve core 22, which passes through the inner annular platform 211 of the valve body 21, is adapted to the inner diameter of the inner annular platform 211 to guide the movement of the valve core 22. A valve body sealing ring 25, which abuts against the outer circumferential surface of the extension section, is provided on the inner wall of the inner annular platform 211. A sealing groove is provided on the inner wall of the inner annular platform 211, and the valve body sealing ring 25 is installed in this sealing groove. When the air valve 2 is in the open state, the inner passage opening of the air passage 222 is located on the side of the valve body sealing ring 25 furthest from the end of the extension section. When the air valve 2 is in the closed state, the inner passage opening of the air passage 222 is located on the side of the valve body sealing ring 25 closest to the end of the extension section. When the air filter 3 is installed in place, the valve core 22 is pushed to move, causing the inner passage opening of the air passage 222 to pass over the valve body sealing ring 25, thus connecting the two axial sides of the valve body sealing ring 25. When the air filter 3 is removed, the inner passage opening of the air duct 222 is located on the side of the valve body sealing ring 25 facing outwards from the cabinet 1, thereby improving the air isolation effect between the inside and outside of the cabinet 1. In other embodiments, the valve body sealing ring may be omitted, and the air isolation between the inside and outside of the cabinet may be achieved solely by the valve core sealing ring when the air valve is closed.

[0039] Combination Figure 6 and Figure 7The air filter 3 includes a housing and two clean modules 36 and a drying module 35 disposed within the housing. The drying module 35 is positioned between the two clean modules 36 in the airflow direction, which helps to ensure the cleanliness of the air entering the cabinet 1. In other embodiments, only one clean module may be provided. The drying module 35 and the clean module 36 are conventional technologies and will not be described in detail here. The housing includes a main housing 33 and an end cap 34 disposed at one end of the main housing 33. An air inlet 32 ​​is provided at the center of the end cap 34. A cylindrical threaded joint is provided at the center of the side wall of the main housing 33 away from the end cap 34. The threaded joint forms an air outlet 31. Outside air enters through the air inlet 32, passes through the drying module 35 to remove moisture and the clean module 36 to remove dust, and then flows out of the air filter 3 from the air outlet 31 and enters the air valve 2. The air outlet 31 here is defined as the end from which the filtered air flows out. It should be understood that the air inlet 32 ​​and the air outlet 31 of the air filter 3, together with the open air valve 2, enable the circulation of air inside and outside the cabinet 1.

[0040] The air chamber inside cabinet 1 is a sealed air chamber with equal atmospheric pressure. This atmospheric pressure sealed air-insulated switchgear can always maintain the insulating gas inside the air chamber as clean and dry air. Air can circulate and exchange between the inside and outside of the air chamber, achieving insulation inside the air chamber of the environmentally friendly switchgear under normal atmospheric pressure. Air filter 3 is easy to replace. When replacing air filter 3, valve 2 automatically closes to prevent unfiltered air from entering cabinet 1. To replace air filter 3, unscrew it from valve body 21. Simultaneously, valve core 22 slides onto valve seat under the force of spring 23, closing the air passage. Untreated air from the atmosphere cannot enter cabinet 1, ensuring that the insulating gas inside cabinet 1 remains pure and dry. Open end cover 34, replace with new clean module 36 and dry module 35, then tighten end cover 34 onto main housing 33. Finally, install air filter 3 onto valve body 21, and air filter 3 can be put back into use.

[0041] Finally, it should be noted that the above description is only a preferred embodiment of this utility model and is not intended to limit this utility model. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still make modifications to the technical solutions described in the foregoing embodiments without creative effort, or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A sealed air-insulated switchgear at normal pressure, characterized in that, The device includes a cabinet with a ventilation port. An air valve is installed at the ventilation port. The air valve includes a valve body and a valve core. The valve body has a valve seat for sealing with the valve core. The valve body or the cabinet has an installation structure for installing an air filter. The air filter has a pusher for pushing the valve core at its outlet end where filtered air flows into the cabinet. The air valve has an open state where the valve core and valve seat are released from sealing when pushed by the pusher to connect the internal space of the cabinet with the outlet end, and a closed state where the valve core and valve seat are sealed together when the pusher is disengaged from the valve core to isolate the internal space of the cabinet from the outside atmosphere.

2. The sealed air insulated switchgear at normal pressure according to claim 1, characterized in that, The valve core has an outer ring platform and an extension section provided on the side of the outer ring platform near the outlet end. The valve body cavity has an inner ring platform for cooperating with the outer ring platform. The inner ring platform forms a valve seat. The end of the extension section passes through the inner ring platform so that the push part can push and contact it.

3. The sealed air insulated switchgear at normal pressure according to claim 2, characterized in that, The extension section is provided with an air passage, which has an outer channel opening for corresponding communication with the air outlet end, and an inner channel opening located on the side of the inner ring platform opposite to the air outlet end when the air valve is in the open state.

4. The sealed air insulated switchgear at normal pressure according to claim 3, characterized in that, The air passage includes an axial blind hole extending along the valve core axis and a radial through hole provided on the wall of the axial blind hole. The opening of the axial blind hole constitutes the outer passage of the air passage, and the opening of the radial through hole located on the outer wall of the valve core constitutes the inner passage of the air passage.

5. The sealed air insulated switchgear at normal pressure according to claim 3 or 4, characterized in that, A valve core sealing ring is provided on the side of the outer ring platform near the extension section. The inner ring platform is provided with a valve seat mating surface for cooperating with the valve core sealing ring. The outer diameter of the extension section is adapted to the inner diameter of the inner ring platform. A valve body sealing ring is provided on the inner wall of the inner ring platform that abuts against the outer circumferential surface of the extension section. When the air valve is in the open state, the inner channel opening is located on the side of the valve body sealing ring away from the end of the extension section. When the air valve is in the closed state, the inner channel opening is located on the side of the valve body sealing ring near the end of the extension section.

6. The sealed air insulated switchgear at normal pressure according to any of claims 1-4, characterized in that, The valve body has an outer end protruding from the outer wall of the cabinet, and the mounting structure for installing the air filter is located at the outer end of the valve body.

7. The sealed air insulated switchgear at normal pressure according to claim 6, characterized in that, The valve body has an internal thread at its outer end, which forms a mounting structure for installing an air filter so that the air filter is threadedly connected to the valve body.

8. The sealed air insulated switchgear at normal pressure according to any of claims 1-4, characterized in that, The valve body is provided with a limiting surface for engaging with the outlet end.

9. The sealed air insulated switchgear at normal pressure according to any of claims 1-4, characterized in that, The valve seat has a conical structure that forms a valve seat mating surface for sealing and engaging with the sealing ring on the valve core.

10. The sealed air insulated switchgear at normal pressure according to any one of claims 1 to 4, characterized in that, The air filter includes a housing and two clean modules and a drying module disposed within the housing, with the drying module positioned between the two clean modules in the airflow direction.

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