Low-temperature-resistant ring main unit
By using L-shaped baffles and extended plate structures to block snow in the ring main unit, and combining this with the heat generated by the striking mechanism and magnets, the problem of outdoor ring main units being difficult to open due to snow melting into ice layers has been solved, thus improving low-temperature resistance and making them easier to open.
Patent Information
- Application Number
- CN202522626246.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-11
- Publication Date
- 2026-01-13
- Estimated Expiration
- 2035-12-11
AI Technical Summary
In northern winters, after snowfall, the doors of outdoor ring main units are difficult to open because the snow melts into ice. Existing methods of knocking can easily damage the doors.
The design incorporates a low-temperature resistant ring main unit, using an L-shaped baffle and extension plate structure to prevent snow from entering the door gaps. It also incorporates a striking element and magnets to generate heat and prevent ice formation. Furthermore, it combines an inflatable cabinet with insulation materials to enhance thermal insulation.
It effectively reduces ice formation, ensures easy opening of cabinet doors, saves energy, and improves the low-temperature resistance of ring main units.
Smart Images
Figure CN223797802U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of ring main unit technology, specifically to a low-temperature resistant ring main unit. Background Technology
[0002] A ring main unit (RMU) is an electrical device consisting of a set of high-voltage switchgear housed in a steel plate metal cabinet or assembled into a modular ring network power supply unit. Its core components include load switches and fuses. It offers advantages such as simple structure, small size, low price, improved power supply parameters and performance, and enhanced power supply safety. RMUs are switchgear used for control and protection in ring-shaped power distribution networks.
[0003] To accommodate the outdoor layout requirements of medium-voltage power distribution networks, outdoor ring main units are installed in areas with concentrated loads, such as residential communities, workshops, and roads. In northern winters, snow can accumulate in the gap between the unit door and the cabinet body. The ring main unit's operating temperature causes the snow to melt, but subsequent cooling forms ice, making the door difficult to open. Currently, the common method to break the ice is by forceful hammering, which can easily damage the door. Utility Model Content
[0004] To address the aforementioned shortcomings, this utility model provides a low-temperature resistant ring main unit that can reduce ice formation and make the cabinet door easy to open.
[0005] This utility model protects a low-temperature resistant ring main unit, which includes a cabinet body containing an inflatable cabinet, and a cabinet door is hinged to the cabinet body;
[0006] The cabinet door has an L-shaped first baffle on the front. The first baffle is close to the lower edge of the cabinet door. When the cabinet door is closed, the first baffle can cover the door gap below the cabinet door to prevent snow from entering from the top and the front.
[0007] The cabinet is equipped with an extension plate and an L-shaped second baffle.
[0008] The extension plate is located above the cabinet door and is perpendicular to the plane of the cabinet door. The extension plate can prevent snow from falling into the gap at the top of the cabinet door.
[0009] The second baffle is located below the cabinet door. When the cabinet door is closed, an L-shaped channel is formed between the second baffle and the first baffle. External gas reaches the lower door gap of the cabinet door through the L-shaped channel, effectively preventing snow from entering.
[0010] Furthermore, the cabinet door includes an inner layer and an outer layer, with the inner layer close to the gas-filled cabinet;
[0011] The outer interlayer is provided with an upper striking element and a lower striking element;
[0012] The upper striking part and the lower striking part protrude from the surface of the cabinet door. When the cabinet door is closed, the external airflow can drive the upper striking part to pass through the upper door gap and strike the cabinet body, while simultaneously driving the lower striking part to pass through the lower door gap and strike the cabinet body, thus preventing ice buildup.
[0013] Furthermore, the upper striking member and the lower striking member have the same structure;
[0014] The upper striking component includes a first connecting rod, the middle position of which is hinged to the outer interlayer via a first pivot. One end of the first connecting rod is fixedly connected to the outer block, and the other end of the connecting rod is hinged to the bottom end of the second connecting rod via a second pivot. A spring is sleeved on the top of the second connecting rod.
[0015] The external block is located outside the cabinet door. The external block is a streamlined block with an upper surface area smaller than the lower surface area. Horizontal gas passing through the external block can exert downward pressure on it, causing the external block to drive the top of the second connecting rod to extend.
[0016] Furthermore, a flexible cover is provided between the outer side of the first connecting rod and the surface of the cabinet door. The flexible cover forms a seal between the first connecting rod and the surface of the cabinet door to prevent external snow from entering the interior of the outer interlayer.
[0017] Furthermore, the outer interlayer is provided with a vertical pipe, the top and bottom of which are connected to the outside, allowing gas to enter from below and exit from the top.
[0018] Both the upper striking element and the lower striking element are disposed inside the pipe;
[0019] An upper magnet is provided on the top outer wall of the pipe, and a lower magnet is provided on the bottom outer wall of the pipe;
[0020] The upper magnet forms an upper magnetic field, and when the upper striking part moves, it can cut the magnetic field lines in the upper magnetic field, forming eddy currents on the upper striking part and generating heat.
[0021] The lower magnet forms a lower magnetic field, and when the lower striking component moves, it can cut the magnetic field lines in the lower magnetic field, forming eddy currents on the lower striking component and generating heat.
[0022] Furthermore, the pipeline includes a first pipeline, a second pipeline, and a third pipeline connected sequentially from top to bottom with their diameters increasing sequentially. Gas enters from the bottom end of the third pipeline and is accelerated out from the top end of the first pipeline.
[0023] The opening area at the top of the first pipe is smaller than the cross-section of the first pipe, allowing a small amount of gas to be discharged.
[0024] Furthermore, the inner wall of the pipe is provided with strip-shaped plates, and the gas can generate heat through friction with the strip-shaped plates.
[0025] Furthermore, the strip is made of one of the following materials: natural rubber, neoprene rubber, or nitrile rubber.
[0026] Furthermore, the inner and outer interlayers are filled with sprayed polyurethane rigid foam or rubber-plastic insulation cotton to improve thermal insulation.
[0027] Beneficial Effects: This utility model features an L-shaped first and second baffle. One panel of the first baffle is perpendicular to the cabinet door, while the other extends downwards parallel to the door. Similarly, one panel of the second baffle is perpendicular to the cabinet body, and the other extends downwards parallel to the body. This creates an L-shaped channel between the first and second baffles, directly blocking snow from the top and front of the cabinet door, preventing naturally falling snow from entering the bottom door gap. Simultaneously, it allows for some air exchange between the inside of the ring main unit and the outside, preventing moisture buildup. The extended baffle also directly blocks snow from entering the top door gap, preventing snow accumulation there. Attached Figure Description
[0028] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0029] in:
[0030] Figure 1 This is a schematic diagram of the overall structure of a low-temperature resistant ring main unit from a first angle in one embodiment of the present invention.
[0031] Figure 2 This is a schematic diagram of the overall structure of a low-temperature resistant ring main unit from a second angle in one embodiment of the present invention.
[0032] Figure 3 for Figure 2 A magnified view of part A in the middle;
[0033] Figure 4 for Figure 2 A magnified view of part B in the middle section;
[0034] Figure 5 for Figure 2 A magnified view of part C in the middle;
[0035] Figure 6 This is a top view of the cabinet door in one embodiment of the present invention;
[0036] Figure 7 for Figure 6 Cross-sectional view in the DD direction;
[0037] Figure 8 for Figure 7 A magnified view of part F in the middle;
[0038] Figure 9 for Figure 6 Cross-sectional view in the EE direction;
[0039] Figure 10 This is a partial cross-sectional view of a low-temperature resistant ring main unit in another embodiment of the present invention;
[0040] Figure 11 for Figure 10 A magnified view of part G in the middle;
[0041] Figure 12 This is a schematic diagram of the overall structure of the upper striking component in one embodiment of the present invention;
[0042] In the diagram, 1 is the cabinet door; 11 is the first baffle.
[0043] 12. Outer layer; 13. Inner layer; 14. Pipe; 141. First pipe; 142. Second pipe; 143. Third pipe; 15. Upper magnet; 16. Upper striking element; 161. External block; 162. First connecting rod; 163. Spring; 164. Second connecting rod; 165. Second pivot; 166. First pivot; 167. Flexible cover; 17. Strip; 18. Lower magnet; 19. Lower striking element;
[0044] 2. Cabinet body; 21. Extension plate; 22. Second baffle;
[0045] 3. Gas-filled cabinet. Detailed Implementation
[0046] The technical solutions of this utility model will be clearly and completely described below with reference to the embodiments of this utility model. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.
[0047] refer to Figures 1-12 This utility model protects a low-temperature resistant ring main unit, which includes a cabinet body 2 containing an air-filled cabinet 3, and a cabinet door 1 hinged to the cabinet body 2, which can be opened or closed.
[0048] The cabinet door 1 has an L-shaped first baffle 11 on its front side. The first baffle 11 is close to the lower edge of the cabinet door 1. When the cabinet door 1 is closed, the first baffle 11 can cover the gap at the bottom of the cabinet door 1 to prevent snow from entering from the top and the front. The front of the cabinet door 1 refers to the direction in which the cabinet door 1 is opened.
[0049] The cabinet 2 is equipped with an extension plate 21 and an L-shaped second baffle 22.
[0050] The extension plate 21 is set above the cabinet door 1. The extension plate 21 is perpendicular to the plane where the cabinet door 1 is located. The extension plate 21 can prevent snow from the top from drifting into the door gap at the top of the cabinet door 1.
[0051] The second baffle 22 is located below the cabinet door 1. When the cabinet door 1 is closed, an L-shaped channel is formed between the second baffle 22 and the first baffle 11. External gas reaches the lower door gap of the cabinet door 1 through the L-shaped channel, effectively preventing snow from entering.
[0052] This utility model features an L-shaped first baffle 11 and a second baffle 22. One plate of the first baffle 11 is perpendicular to the cabinet door 1, while the other plate extends downwards parallel to the cabinet door 1. Similarly, one plate of the second baffle 22 is perpendicular to the cabinet body 2, and the other plate also extends downwards parallel to the cabinet body 2. This forms an L-shaped channel between the first baffle 11 and the second baffle 22, directly blocking snow from the top and front of the cabinet door 1, preventing naturally falling snow from entering the bottom door gap. Simultaneously, it allows for the entry of air, ensuring a small amount of ventilation between the inside of the ring main unit and the outside, preventing the accumulation of internal moisture. An extension plate 21 directly blocks snow from entering the top door gap, preventing snow accumulation there. Preferably, the extension plate 21 is positioned close to the top door gap to significantly prevent snow from entering, avoiding melting snow that freezes at low temperatures and ensuring smooth opening of the cabinet door 1.
[0053] In practical use, outdoor ring main units are prone to snow entering the lower door gap due to their low location and downward airflow, which then melts and freezes. This invention features an L-shaped channel with an opening facing downwards. When the cabinet door 1 is closed naturally, neither naturally falling snow nor snow blown up by the wind can easily reach the lower door gap through this right-angled channel, effectively reducing the possibility of subsequent icing.
[0054] refer to Figure 6 , Figure 7 and Figure 10 In one specific embodiment, the cabinet door 1 includes an inner layer 13 and an outer layer 12, with the inner layer 13 close to the gas-filling cabinet 3;
[0055] The outer interlayer 12 is provided with an upper striking element 16 and a lower striking element 19;
[0056] Parts of the upper striking member 16 and the lower striking member 19 protrude from the front surface of the cabinet door 1. When the cabinet door 1 is closed, the external airflow can drive the upper striking member 16 through the upper door gap to strike the cabinet body 2, and at the same time drive the lower striking member 19 through the lower door gap to strike the cabinet body 2, thus preventing ice buildup.
[0057] This embodiment, by setting an inner layer 13 and an outer layer 12, forms a double-layer structure, which has a better heat preservation effect, allowing the heat of the gas-filled cabinet 3 to remain on the cabinet door 1 for a longer period of time, reducing the formation of ice in the door gaps. By setting an upper striking member 16 and a lower striking member 19, when there is air flow on the outside of the cabinet door 1, the upper striking member 16 and the lower striking member 19 are driven to move, passing through the upper and lower door gaps respectively to strike the cabinet body 2. When striking the cabinet body 2, any existing ice layer can be broken up. The broken ice will move with the continuous striking action and be discharged from the door gaps, preventing it from accumulating inside. For door gaps where no ice layer has formed, the striking can effectively reduce the formation of ice layers, or even thicker ice layers.
[0058] refer to Figure 7 , Figure 8 and Figure 12 In one specific embodiment, the upper striking member 16 and the lower striking member 19 have the same structure, but the internal component connections are different, resulting in different striking directions. The upper striking member 16 strikes upwards, and the lower striking member 19 strikes downwards.
[0059] The upper striking member 16 includes a first connecting rod 162. The middle position of the first connecting rod 162 is hinged to the outer interlayer 12 through a first pivot 166. One end of the first connecting rod 162 is fixedly connected to the outer block 161. The other end of the first connecting rod 162 is hinged to the bottom end of the second connecting rod 164 through a second pivot 165. A spring 163 is sleeved on the top of the second connecting rod 164.
[0060] Specifically, refer to Figure 8 The first rotating shaft 166 is fixed inside the outer interlayer 12, and the first connecting rod 162 can rotate around the axis of the first rotating shaft 166. The second rotating shaft 165 is fixed to the bottom end of the second connecting rod 164. The first rotating shaft 166 has a strip-shaped through hole that extends axially along the first rotating shaft 166. The strip-shaped through hole is fitted onto the second rotating shaft 165, achieving a hinged connection that allows the second connecting rod 164 to move vertically. In practical applications, the second connecting rod 164 will be vertically limited to prevent the second rotating shaft 165 from dislodging from the strip-shaped through hole. The length of the strip-shaped through hole will also be adjusted according to the actual situation to allow the second connecting rod 164 to extend smoothly.
[0061] by Figure 8The direction of movement is explained in the diagram. When the outer block 161 end (left end) of the first connecting rod 162 moves vertically downward, the first connecting rod 162 rotates around the first rotating shaft 166, causing the strip-shaped through hole end (right end) of the first connecting rod 162 to move vertically upward. The strip-shaped through hole drives the second rotating shaft 165 and the second connecting rod 164 to move upward and extend. When they extend, the spring 163 is compressed and contracts. When the external gas flow rate decreases, the spring 163 can extend, causing the second connecting rod 164 to move downward and return to its original position.
[0062] An external block 161 is located outside the cabinet door 1. The external block 161 is a streamlined block with an upper surface area smaller than its lower surface area. According to Bernoulli's principle, when horizontal gas passes through the external block 161, the flow velocity is higher and the pressure is lower on the lower surface. This pressure difference exerts downward pressure on the external block 161, causing it to drive the top of the second connecting rod 164 to extend. The spring 163 can reset the second connecting rod 164, causing it to strike upwards. Similarly, the external block in the lower striking member 19 has an upper surface area larger than its lower surface area, and the pressure difference causes it to exert upward pressure, causing the lower striking member 19 to strike downwards.
[0063] Since the upper striking member 16 and the lower striking member 19 have the same structure and effect, the explanation will focus on the upper striking member 16. This example utilizes a streamlined external block 161, which leverages external airflow to generate upward pressure, thereby extending the second connecting rod 164 upwards. This, in conjunction with the spring 163, enables striking. The entire process requires no electrical energy input, saving energy. Different types of springs 163 can be used to adjust the striking force of the second connecting rod 164, preventing damage to the cabinet 2.
[0064] refer to Figure 7 and Figure 8In one specific embodiment, a flexible cover 167 is provided between the outer side of the first connecting rod 162 and the surface of the cabinet door 1. The flexible cover 167 forms a seal between the first connecting rod 162 and the surface of the cabinet door 1, preventing external snow from entering the interior of the outer interlayer 12. Specifically, after a strip-shaped through hole is opened on the surface of the cabinet door 1, the first connecting rod 162 extends out through the strip-shaped through hole. To prevent snow from entering the outer interlayer 12 through the strip-shaped through hole, a flexible cover 167 is provided for sealing. The flexible cover 167 is made of a low-temperature resistant material, which can achieve sealing without hindering the movement of the first connecting rod 162. The flexible material can be selected as polytetrafluoroethylene (PTFE) composite fabric, which has a melting temperature of 324℃, a decomposition temperature of 415℃, an embrittlement temperature of -190℃, and a heat distortion temperature (under 0.46MPa) of 120℃, making it suitable for outdoor environments. The flexible material can also be selected as silicone rubber, which has good low-temperature resistance and can generally still work at -55℃. With the introduction of phenyl groups, the temperature can reach -73°C. Silicone rubber also has outstanding heat resistance, capable of operating continuously at 180°C, making it suitable for outdoor environments as well.
[0065] refer to Figure 8 and Figure 9 In one specific embodiment, the outer interlayer 12 is provided with a vertical pipe 14, the top and bottom of the pipe 14 are connected to the outside, and gas can enter from the bottom and exit from the top.
[0066] Both the upper striking element 16 and the lower striking element 19 are located inside the pipe 14.
[0067] Two upper magnets 15 are provided on the top outer wall of the pipe 14, symmetrically arranged along the axis of the pipe 14. Two lower magnets 18 are provided on the bottom outer wall of the pipe 14, symmetrically arranged along the axis of the pipe 14.
[0068] An upper magnetic field is formed between the two upper magnets 15. When the upper striking part 16 moves, it can cut the magnetic field lines in the upper magnetic field, forming eddy currents on the upper striking part 16 and generating heat. A lower magnetic field is formed between the two lower magnets 18. When the lower striking part 19 moves, it can cut the magnetic field lines in the lower magnetic field, forming eddy currents on the lower striking part 19 and generating heat.
[0069] In this embodiment, by setting an upper magnet 15 and a lower magnet 18, when the upper striking member 16 moves, it causes the first connecting rod 162 to move and cut the magnetic field lines in the upper magnetic field, generating eddy currents and heating up the first connecting rod 162. The first connecting rod 162, inside the pipe 14, heats the internal gas, causing the hot gas to rise and exit from the top of the pipe 14. This has a blowing effect on the door gap above the cabinet door 1, preventing snow from accumulating in the upper door gap and reducing the possibility of ice formation; it also raises the temperature of the upper door gap, further reducing the possibility of ice formation. The function of the lower magnet 18 is to heat up the lower striking member 19, ultimately heating the gas inside the pipe 14, which will not be elaborated further here. The heat generated by the eddy currents is not very high; therefore, the gas flow rate and volume inside the pipe 14 are not very large. Thus, the gas enters the bottom of the pipe 14 through the L-shaped channel from the lower door gap and exits from the top of the pipe 14. Gas flows in through the lower door gap. If there is ice in the lower door gap, the flowing gas increases sublimation, which can reduce the volume of the ice layer; if there is no ice in the lower door gap, the flowing gas can also reduce the formation of ice.
[0070] refer to Figure 9 In one specific embodiment, the pipe 14 includes a first pipe 141, a second pipe 142, and a third pipe 143 connected sequentially from top to bottom with increasing diameters. Gas enters from the bottom end of the third pipe 143 and is accelerated out from the top end of the first pipe 141. The opening area at the top end of the first pipe 141 is smaller than the cross-sectional area of the first pipe 141, allowing a small amount of gas to be discharged.
[0071] In this embodiment, the pipe 14 is narrow at the top and wide at the bottom, which accelerates the gas upwards. The accelerated gas is discharged from the top of the pipe 14, and the discharged gas itself can impact the upper door seam, further preventing snow accumulation. By reducing the opening at the top of the first pipe 141, the overall gas exchange rate inside the pipe 14 can be reduced. This has two advantages: firstly, it maintains the temperature inside the pipe 14, allowing heat to be transferred to the cabinet door 1; secondly, it prevents snow from being forcefully sucked in at the bottom of the pipe 14 and entering the lower door seam, forming an ice layer.
[0072] refer to Figure 8 and Figure 11 In one specific embodiment, strip-shaped plates 17 are provided on the inner wall of the pipe 14. The friction between the gas and the strip-shaped plates 17 generates heat. By providing the strip-shaped plates 17, the gas inside the pipe 14 can generate heat by rubbing against the strip-shaped plates 17 when it accelerates upward. In this way, when the upper striking member 16 and the lower striking member 19 stop working due to wind or other reasons, the frictional heat between the strip-shaped plates 17 and the gas can also raise the temperature of the gas inside the pipe 14.
[0073] Preferably, the strip 17 is made of one of natural rubber, neoprene rubber, or nitrile rubber. Natural rubber can operate at temperatures as low as -50°C; neoprene rubber can operate at temperatures from -40°C to -50°C; and nitrile rubber can operate at temperatures from -40°C to -45°C. All three meet the requirements for outdoor low-temperature operation.
[0074] In one specific embodiment, the inner layer 13 and the outer layer 12 are filled with sprayed rigid polyurethane foam or rubber-plastic insulation cotton to improve thermal insulation. Specifically, to increase rigidity, some support plates can be set in the inner layer 13 and the outer layer 12, and rigid polyurethane foam can be filled between the support plates, which will have a better effect.
[0075] In this embodiment, by using sprayed polyurethane rigid foam, irregular spaces can be fully filled, especially the complex structure within the outer layer 12, which has a pipe-like structure, making it more suitable for sprayed polyurethane rigid foam and giving the cabinet door 1 better insulation. Rubber-plastic insulation cotton is used because it absorbs almost no water, effectively preventing condensation, which is a significant advantage as insulation material for ring main units, especially as insulation material for the inner layer 13. By using insulation material, firstly, heat loss from the gas-filled cabinet 3 is reduced, allowing for a better seal on the inner sealing strip of the cabinet door 1. Secondly, it reduces heat loss from the pipes 14 within the outer layer 12, ensuring the temperature and gas flow of the cabinet door 1; both factors work together to reduce the formation of ice layers in the upper and lower door seams.
[0076] The above-disclosed embodiments are merely preferred embodiments of the present utility model and should not be construed as limiting the scope of the present utility model. Therefore, any equivalent variations made in accordance with the claims of the present utility model shall still fall within the scope of the present utility model.
Claims
1. A low-temperature resistant ring main unit, characterized in that, Includes a cabinet (2) containing an air-filled cabinet (3), and the cabinet (2) is hinged with a cabinet door (1); The cabinet door (1) has an L-shaped first baffle (11) on its front side. The first baffle (11) is close to the lower edge of the cabinet door (1). When the cabinet door (1) is closed, the first baffle (11) can block the door gap below the cabinet door (1) to prevent snow from entering from the top and front. The cabinet (2) is provided with an extension plate (21) and an L-shaped second baffle (22); The extension plate (21) is located above the cabinet door (1). The extension plate (21) is perpendicular to the plane of the cabinet door (1). The extension plate (21) can prevent snow from falling into the gap at the top of the cabinet door (1). The second baffle (22) is located below the cabinet door (1). When the cabinet door (1) is closed, an L-shaped channel is formed between the second baffle (22) and the first baffle (11). External gas reaches the lower door gap of the cabinet door (1) through the L-shaped channel, effectively preventing snow from entering.
2. The low-temperature resistant ring main unit according to claim 1, characterized in that, The cabinet door (1) includes an inner layer (13) and an outer layer (12), with the inner layer (13) close to the gas cabinet (3). The outer interlayer (12) is provided with an upper striking element (16) and a lower striking element (19). Parts of the upper striking member (16) and the lower striking member (19) protrude from the front surface of the cabinet door (1). When the cabinet door (1) is closed, the external airflow can drive the upper striking member (16) to pass through the upper door gap and strike the cabinet body (2), while simultaneously driving the lower striking member (19) to pass through the lower door gap and strike the cabinet body (2), thus preventing ice buildup.
3. The low-temperature resistant ring main unit according to claim 2, characterized in that, The upper striking member (16) and the lower striking member (19) have the same structure; The upper striking member (16) includes a first connecting rod (162), the middle position of which is hinged to the outer interlayer (12) via a first pivot (166). One end of the first connecting rod (162) is fixedly connected to the outer block (161), and the other end of the first connecting rod (162) is hinged to the bottom end of the second connecting rod (164) via a second pivot (165). The top of the second connecting rod (164) is fitted with a spring (163). The external block (161) is disposed outside the cabinet door (1). It is a streamlined block with an upper surface area smaller than the lower surface area. Gas in the horizontal direction can exert downward pressure on it through the external block (161), causing the external block (161) to drive the top of the second connecting rod (164) to extend.
4. The low-temperature resistant ring main unit according to claim 3, characterized in that, A flexible cover (167) is provided between the outer side of the first connecting rod (162) and the surface of the cabinet door (1). The flexible cover (167) forms a seal between the first connecting rod (162) and the surface of the cabinet door (1) to prevent external snow from entering the interior of the outer interlayer (12).
5. The low-temperature resistant ring main unit according to claim 2, characterized in that, The outer interlayer (12) is provided with a vertical pipe (14), the top and bottom of the pipe (14) are connected to the outside, and gas can enter from the bottom and exit from the top. Both the upper striking element (16) and the lower striking element (19) are disposed inside the pipe (14); An upper magnet (15) is provided on the top outer wall of the pipe (14), and a lower magnet (18) is provided on the bottom outer wall of the pipe (14). The upper magnet (15) forms an upper magnetic field. When the upper striking part (16) moves, it can cut the magnetic field lines in the upper magnetic field and form eddy currents on the upper striking part (16), generating heat. The lower magnet (18) forms a lower magnetic field. When the lower striking member (19) moves, it can cut the magnetic field lines in the lower magnetic field, forming eddy currents on the lower striking member (19) and generating heat.
6. The low-temperature resistant ring main unit according to claim 5, characterized in that, The pipe (14) includes a first pipe (141), a second pipe (142) and a third pipe (143) connected sequentially from top to bottom and with increasing diameters. Gas enters from the bottom end of the third pipe (143) and is accelerated out from the top end of the first pipe (141). The top opening area of the first pipe (141) is smaller than the cross-section of the first pipe (141), allowing a small amount of gas to be discharged.
7. The low-temperature resistant ring main unit according to claim 5, characterized in that, The inner wall of the pipe (14) is provided with strips (17), and the gas can generate heat through friction with the strips (17).
8. The low-temperature resistant ring main unit according to claim 7, characterized in that, The strip (17) is made of one of the following materials: natural rubber, chloroprene rubber, or nitrile rubber.
9. The low-temperature resistant ring main unit according to claim 2, characterized in that, The inner layer (13) and the outer layer (12) are filled with sprayed polyurethane rigid foam or rubber and plastic insulation cotton to improve the insulation performance.