Cold-resistant low-smoke low-pressure power cable

Abstract

The application discloses a cold-resistant low-smoke air-tight explosion-proof low-voltage power cable and relates to the technical field of cables. An extruded air-tight assembly is arranged on the outer side of an inner insulation layer, a reinforced heat-conducting wire is arranged in a middle supporting pipe, a one-way air pipe is installed through the middle of an air-tight plate, flexible isolation boxes are uniformly arranged on the outer side of the middle supporting pipe, a sealing rubber strip is filled in the gap of an armored layer, and a curved supporting assembly is wrapped on the outer side of an outer protective layer. The application has the advantages that when the conductor is electrified, carbon dioxide will expand and extrude the conductor and the filling layer due to heat, the inner protective layer is tightly attached to the armored layer with high hardness, the gap between the armored layers is closed by the sealing rubber strip, the expansion rate of carbon dioxide is higher than that of air, the cable is extruded in the internal gap, the cable is more compact, the internal air is reduced, the air tightness of the cable is better, the cable is not easily damaged due to extrusion, even if the cable is on fire at high temperature, carbon dioxide can inhibit the combustion, and the fire spreading can be better avoided.

Description

Technical Field

[0001] This invention relates to the field of cable technology, specifically to a cold-resistant, low-smoke, airtight, explosion-proof low-voltage power cable. Background Technology

[0002] Low-voltage power cables are core equipment used in 0.66kV-3kV power distribution networks and industrial power transmission. Their applications are mainly concentrated in the following scenarios: urban and building power distribution, power supply for petrochemical industrial facilities, and new energy scenarios. Special cables are required in low-temperature and explosion-prone areas to ensure normal power transmission.

[0003] However, when low-voltage electrical cables are used in low-temperature and explosion-prone areas, the air inside the cable is often loose and easily ruptured by external pressure. Furthermore, the air inside the cable can fuel combustion when the cable overheats. Conventional cables, due to the lack of sealing measures in their internal structure, have channels for gas flow. Since gas can penetrate anywhere, flammable and explosive gases, vapors, or dust can be gradually conducted from the danger zone to the safe zone under the influence of external environmental pressure. Over time, this accumulation can cause cable damage or even explosion, thus reducing environmental safety. Summary of the Invention

[0004] This invention provides a cold-resistant, low-smoke, airtight, explosion-proof low-voltage power cable, which can effectively solve the problems mentioned in the background art. When used in low-temperature and explosion-prone areas, the cable often contains air, which is loose inside and easily ruptured by external pressure. Furthermore, the air inside the cable can fuel combustion when the cable overheats. Conventional cables, due to the lack of internal sealing measures, have channels for gas flow. Flammable and explosive gases accumulate over time, causing cable damage or even explosion, thus reducing their safety.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a cold-resistant, low-smoke, airtight, explosion-proof low-voltage power cable, comprising a conductor, an inner insulation layer wrapped around the outside of the conductor, and an extrusion airtight assembly disposed on the outside of the inner insulation layer, the extrusion airtight assembly comprising a central support tube;

[0006] A central support tube is provided between the three inner insulation layers. A heat-conducting wire is provided inside the central support tube. An air-insulating plate is uniformly sleeved on the outside of the heat-conducting wire. A one-way air pipe is installed through the middle of the air-insulating plate. Flexible isolation boxes are uniformly provided on the outside of the central support tube. Ventilation holes are provided near the flexible isolation boxes of the central support tube.

[0007] An inner sheath is sleeved on the outside of the inner insulation layer, and an armor layer is wrapped around the outside of the inner sheath. Sealing strips are filled in the gaps of the armor layer. An outer sheath is wrapped around the outside of the armor layer. Buffer grooves are evenly formed on the side of the outer sheath near the armor layer, and buffer strips are filled inside the buffer grooves.

[0008] According to the above technical solution, the inner protective layer is filled with a filling layer, and flame-retardant rubber rings are uniformly sleeved on the outer side of the inner protective layer. A spiral antifreeze bag is sleeved on the side of the flame-retardant rubber rings of the inner protective layer.

[0009] According to the above technical solution, the flexible isolation box has uniformly opened cavities inside, and the end of the flexible isolation box away from the central support tube contacts the inner side of the inner protective layer.

[0010] According to the above technical solution, the outer side of the middle support tube is composed of several arc-shaped curved surfaces that are attached to the inner insulating layer, and the inside of the middle support tube is filled with carbon dioxide gas.

[0011] According to the above technical solution, the inner protective layer has an embedding groove at the corresponding flame-retardant rubber ring and spiral antifreeze bag, the spiral antifreeze bag and the flame-retardant rubber ring are aligned on the outside, and the spiral antifreeze bag is filled with antifreeze.

[0012] According to the above technical solution, a bending support assembly is wrapped around the outer side of the outer protective layer, and the bending support assembly includes an outer heat insulation pipe;

[0013] The outer protective layer is wrapped with an outer heat insulation pipe. The outer heat insulation pipe has evenly spaced embedded support grooves. The outer heat insulation pipe is wrapped with a heat equalization layer. C-shaped clips are evenly fitted on the outer side of the heat equalization layer. Support holes are evenly spaced in the middle of the C-shaped clips. A spring plate is installed through the support hole.

[0014] Both ends of the spring plate are fitted with end tubes. A rolling rod is rotatably embedded at the end of the end tube away from the spring plate. The spring plate is evenly provided with mating grooves corresponding to the end tubes. The end tubes are provided with mating holes corresponding to the mating grooves. A positioning pin is embedded inside the mating hole.

[0015] According to the above technical solution, the C-type card has anti-slip pads uniformly embedded on the side near the outer protective layer, and the anti-slip pads are attached to the heat dissipation layer.

[0016] According to the above technical solution, a movable end plate is welded to one end of the C-type card, and a fixed end plate is welded to the other end of the C-type card. A connecting screw is symmetrically and rotatably installed on the fixed end plate. The connecting screw is connected to the movable end plate through a screw hole. A dustproof hose is sleeved on the connecting screw at the position between the movable end plate and the fixed end plate.

[0017] According to the above technical solution, the end of the end tube away from the spring plate is rounded, the support groove is inlaid with a reinforcing strip on the outside of the heat dissipation layer, and the rolling rod contacts the reinforcing strip.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] 1. Equipped with an extrusion airtight component, the conductor heats up when energized, heating the carbon dioxide inside the middle support tube and air barrier. The enhanced heat-conducting wire transfers the heat to other areas of the middle support tube. The carbon dioxide expands when heated, extruding the conductor and filler layer, and extruding the inner sheath tightly against the high-hardness armor layer. The gaps between the armor layers are sealed with sealing strips. Because the thermal expansion rate of carbon dioxide is greater than that of air, the compression within the cable's internal gaps makes the cable more compact and reduces the amount of air inside. This results in better internal airtightness of the cable, making it less susceptible to damage from compression. Even if the cable catches fire at high temperatures, the carbon dioxide will inhibit combustion, better preventing the fire from spreading.

[0020] Furthermore, if the cable catches fire at high temperatures, the internal temperature will continue to rise, causing the aluminum hydroxide inside the flame-retardant rubber ring to decompose and the flame-retardant rubber ring to expand, dividing the cable into multiple sections to prevent the fire from spreading and further prevent the occurrence of a fire, thus ensuring higher safety.

[0021] 2. It is equipped with a bending support component. If the external low temperature is unevenly distributed, the heat dissipation layer will disperse the low temperature and prevent the low temperature from concentrating and damaging the local low temperature area.

[0022] During cable laying, when encountering locations that require bending or are frequently bent during use, C-type clips are attached to the bending locations of the cable, and spring plates are inserted into the support holes. End tubes are fitted onto both ends of the spring plates. When bending, the rolling rods at the ends of the end tubes will roll on the inside of the cable at the bending location, and the spring plates will also fully compress the inside of the cable bend, preventing the cable from bending excessively and cracking at low temperatures, thus better protecting the cable and giving it a longer service life.

[0023] In summary, the extrusion airtight assembly improves the airtightness of the cable, and the multiple flame-retardant structures better prevent cable problems caused by fire. The bending support assembly prevents excessive bending during bending through C-shaped clips and spring plates. At the same time, the liquid inside the spiral antifreeze bag flows during bending, squeezing the internal cable and hindering bending. Furthermore, the outer heat insulation pipe and heat-equalizing layer of the bending support assembly better prevent damage to the cable from low temperatures. The two components work together to better protect the cable. Attached Figure Description

[0024] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0025] In the attached diagram:

[0026] Figure 1 This is a schematic diagram of the structure of the present invention;

[0027] Figure 2 This is a schematic diagram of the structure of the extrusion airtight component of the present invention;

[0028] Figure 3 This is a schematic diagram of the installation structure of the flame-retardant rubber ring of the present invention;

[0029] Figure 4 This is a schematic diagram of the installation structure of the filling layer of the present invention;

[0030] Figure 5 This is a schematic diagram of the installation structure of the flexible isolation box of the present invention;

[0031] Figure 6 This is the present invention. Figure 5 A schematic diagram of the structure of region A;

[0032] Figure 7 This is a schematic diagram of the bending support assembly of the present invention;

[0033] Figure 8 This is a schematic diagram of the installation structure of the rolling rod of the present invention;

[0034] Labels in the diagram: 1. Conductor; 2. Inner insulation layer;

[0035] 3. Extrusion airtight assembly; 301. Middle support tube; 302. Reinforced heat-conducting wire; 303. Air baffle; 304. One-way air pipe; 305. Flexible isolation box; 306. Ventilation hole; 307. Inner protective layer; 308. Filling layer; 309. Flame-retardant rubber ring; 310. Spiral antifreeze bag; 311. Armor layer; 312. Sealing strip; 313. Outer protective layer; 314. Buffer groove; 315. Buffer strip;

[0036] 4. Bending support assembly; 401. External heat insulation pipe; 402. Support groove; 403. Heat dissipation layer; 404. C-type clip; 405. Anti-slip pad; 406. Support hole; 407. Spring plate; 408. End tube; 409. Rolling rod; 410. Butt groove; 411. Butt hole; 412. Positioning pin; 413. Movable end plate; 414. Fixed end plate; 415. Connecting screw; 416. Dustproof hose; 417. Reinforcing strip. Detailed Implementation

[0037] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0038] Example: Figure 1-8As shown, the present invention provides a technical solution for a cold-resistant, low-smoke, airtight, explosion-proof low-voltage power cable, including a conductor 1, an inner insulation layer 2 wrapped around the outside of the conductor 1, and an extrusion airtight assembly 3 disposed on the outside of the inner insulation layer 2. The extrusion airtight assembly 3 includes a central support tube 301, a reinforcing heat-conducting wire 302, an air barrier 303, a one-way air pipe 304, a flexible isolation box 305, a ventilation hole 306, an inner sheath 307, a filling layer 308, a flame-retardant rubber ring 309, a spiral antifreeze bag 310, an armor layer 311, a sealing strip 312, an outer sheath 313, a buffer groove 314, and a buffer strip 315.

[0039] A central support tube 301 is disposed between the three inner insulation layers 2. The outer side of the central support tube 301 is composed of several arc-shaped curved surfaces that fit the inner insulation layers 2. The interior of the central support tube 301 is filled with carbon dioxide gas to facilitate the installation of the central support tube 301 and the inner insulation layers 2. A reinforcing heat-conducting wire 302 is disposed inside the central support tube 301. A gas-insulating plate 303 is uniformly sleeved on the outer side of the reinforcing heat-conducting wire 302. A one-way gas pipe 304 is installed through the middle of the gas-insulating plate 303. Flexible isolation boxes 305 are uniformly disposed on the outer side of the central support tube 301. The flexible isolation boxes 305 have uniformly opened cavities inside. The end of the flexible isolation box 305 away from the central support tube 301 contacts the inner side of the inner protective layer 307 to facilitate the flexible isolation box. 305 expands when heated, making the inside of the cable more compact. Ventilation holes 306 are provided near the flexible isolation box 305 in the middle support tube 301. An inner sheath 307 is sleeved on the outside of the inner insulation layer 2. The inner sheath 307 is filled with a filling layer 308. Flame-retardant rubber rings 309 are uniformly sleeved on the outside of the inner sheath 307. A spiral antifreeze bag 310 is sleeved on one side of the inner sheath 307 and the flame-retardant rubber ring 309. An embedding groove is provided on the inner sheath 307 corresponding to the flame-retardant rubber ring 309 and the spiral antifreeze bag 310. The spiral antifreeze bag 310 and the flame-retardant rubber ring 309 are aligned on the outside. The spiral antifreeze bag 310 is filled with antifreeze to facilitate the installation of the flame-retardant rubber ring 309 and the spiral antifreeze bag 310.

[0040] The inner protective layer 307 is wrapped with an armor layer 311 on the outside. The gaps in the armor layer 311 are filled with sealing strips 312. The outer protective layer 313 is wrapped with an outer protective layer 313. The outer protective layer 313 has a buffer groove 314 evenly distributed on the side near the armor layer 311. The buffer groove 314 is filled with a buffer strip 315.

[0041] The outer protective layer 313 is wrapped with a bending support assembly 4. The bending support assembly 4 includes an outer heat insulation pipe 401, a support groove 402, a heat equalization layer 403, a C-shaped clip 404, an anti-slip pad 405, a support hole 406, a spring plate 407, an end pipe 408, a rolling rod 409, a docking groove 410, a docking hole 411, a positioning pin 412, a movable end plate 413, a fixed end plate 414, a connecting screw 415, a dustproof hose 416, and a reinforcing strip 417.

[0042] The outer protective layer 313 is wrapped with an outer heat insulation pipe 401. The outer heat insulation pipe 401 is uniformly provided with embedded support grooves 402. The outer heat insulation pipe 401 is wrapped with a heat-spreading layer 403. C-shaped clips 404 are uniformly fitted on the outer side of the heat-spreading layer 403. Anti-slip pads 405 are uniformly embedded on the side of the C-shaped clips 404 near the outer protective layer 313. The anti-slip pads 405 are in contact with the heat-spreading layer 403, which makes it easier for the C-shaped clips 404 to fit better into the heat-spreading layer 403. Support holes 406 are uniformly provided in the middle of the C-shaped clips 404. A spring plate 407 is installed through the support hole 406.

[0043] Both ends of the spring plate 407 are fitted with end tubes 408. A rolling rod 409 is rotatably embedded at the end of the end tube 408 away from the spring plate 407. The end of the end tube 408 away from the spring plate 407 has a rounded corner. A reinforcing strip 417 is embedded in the support groove 402 on the outside of the heat dissipation layer 403. The rolling rod 409 contacts the reinforcing strip 417 to facilitate the rolling rod 409 rolling on the outside of the cable. The spring plate 407 is evenly provided with mating grooves 410 corresponding to the end tubes 408. The end tubes 408 are provided with mating holes 411 corresponding to the mating grooves 410. A positioning pin 412 is embedded inside the mating hole 411.

[0044] A movable end plate 413 is welded to one end of the C-type card 404, and a fixed end plate 414 is welded to the other end of the C-type card 404. A connecting screw 415 is symmetrically mounted on the fixed end plate 414. The connecting screw 415 is connected to the movable end plate 413 through a screw hole. A dustproof hose 416 is sleeved on the connecting screw 415 at the position between the movable end plate 413 and the fixed end plate 414.

[0045] The working principle and usage process of this invention are as follows: Conductor 1 is a Class II stranded compacted round copper conductor. An inner insulation layer 2, made of PVC, is wrapped around the outside of conductor 1 using an extruder. Conductor 1, wrapped with the inner insulation layer 2, is temporarily bonded and fixed to the outside of the middle support tube 301. Subsequently, a flexible isolation box 305, made of heat-resistant rubber, is bonded to the outside of the middle support tube 301. Then, one end of the middle support tube 301 is sealed, and the air inside the middle support tube 301 is extracted to create a negative pressure, wrapping a filling layer 308. The filling layer 308 is non-hygroscopic. Before the filling layer 308 is completely cooled, the inner protective layer 307 is wrapped by an extruder. The inner protective layer 307 is made of low-smoke, low-halogen, flame-retardant, and cold-resistant polyvinyl chloride. The extrusion molding process is used to inject the plastic material into the annular gap between the inner protective layer 307 and the cabling structure in a molten state. This makes the inner protective layer 307 and the outer layer of the cabling form an integral structure without interface gaps, achieving a tight fit between the inner protective layer 307 and the cabling structure, forming an intermediate sealing barrier, and blocking the migration path of the inner layer moisture to the armor layer 311.

[0046] During the above process, the inner protective layer 307 and the filler layer 308 have high temperatures when passing through the extruder, and the internal temperatures of the middle support tube 301 and the flexible isolation box 305 are also high. After cooling, a flame-retardant rubber ring 309 and a spiral antifreeze bag 310 are embedded and installed on the outside. The flame-retardant rubber ring 309 is made of PVC material mixed with aluminum hydroxide particles. An armor layer 311 is then wrapped around the outside, and sealing strips 312 are filled into the gaps of the spiral armor layer 311 to seal the gaps and improve the overall sealing performance. The filling is achieved by using a precision dispensing device to quantitatively apply electronic silicone along the spiral channel of the steel strip, sealing the steel... With an inner spiral channel, a continuous sealing layer is formed after curing. The buffer strip 315 is temporarily fixed to the outside of the armor layer 311. The extruder wraps the outer protective layer 313, which is made of low-smoke, low-halogen, flame-retardant, and cold-resistant polyvinyl chloride. The outer protective layer 313 adopts a semi-extrusion tube forming process, which wraps the outer protective material around the steel strip. The extrusion pressure makes the semi-extruded tube and the wrapping tape fit tightly and fill the micro gaps on the surface of the wrapping tape. Carbon dioxide gas is filled into the middle support tube 301, and the remaining small amount of air in the middle support tube 301 and the flexible isolation box 305 is squeezed out through the one-way air tube 304.

[0047] The conductor compaction process minimizes the gaps between the single filaments of conductor 1. Then, high-viscosity, room-temperature curing electronic silicone is used to fill the microscopic gaps in the compacted conductor 1 through injection molding. The injection molding and conductor stranding are carried out simultaneously to achieve an airtight seal of the entire conductor. Through the synergistic effect of "compaction + bonding", the intrusion path of flammable and explosive gases and dust along the gaps between the single filaments of the conductor is blocked, achieving conductor airtightness. This effectively prevents the diffusion of flammable media along the axial gaps of the cable, thereby avoiding the possibility of explosion risks caused by the cable passing through cross-regional areas, such as the conduction of flammable and explosive gases, vapors or dust from the danger zone to the safe zone along the cable.

[0048] After cable production, it needs to be tested. The testing method is as follows: Take a 0.5m cable sample, install one section in a container, and then supply a residual pressure of not less than 0.3kPa into the container. After that, seal the inlet, while keeping the outlet closed. Record the steady-state pressure after 5 minutes. Then, open the outlet; and after 5 seconds, record the pressure value inside the container using a pressure gauge. The residual pressure inside the container should not be less than 0.15kPa to ensure that the structure of each part does not shift during the production process and to ensure the airtightness requirements are met.

[0049] Due to the special properties of its material, it can be laid directly at an ambient temperature of -20℃ without heating or preheating, solving the problem of not being able to lay cables in winter or cold regions, improving the progress of projects in low-temperature environments and reducing the difficulty of cable laying.

[0050] If the environment of the laying area is more severe and the temperature distribution is uneven, an outer heat insulation pipe 401 and a heat-dampening layer 403 are wrapped around the outer sheath 313 in sequence. The outer heat insulation pipe 401 is made of aluminum foil fiberglass cloth, the heat-dampening layer 403 is made of graphene heat-dampening coating, and the reinforcing strip 417 is embedded in the support groove 402. The reinforcing strip 417 is made of low-temperature resistant PVC material, thus completing the cable production.

[0051] During use, the inner sheath 307, outer sheath 313, and outer heat insulation tube 401 have good heat insulation performance, avoiding the impact of low external temperature on the inside of the cable. If the low external temperature is unevenly distributed, the heat distribution layer 403 will disperse the low temperature, preventing the low temperature from concentrating and damaging the local low temperature area. When the conductor 1 is energized, it will heat up, heating the carbon dioxide inside the middle support tube 301 and the air barrier 303. The heat-conducting wire 302 will transfer the heat to other areas of the middle support tube 301. The carbon dioxide expands when heated, squeezing the conductor 1 and the filling layer 308, squeezing the inner sheath 307 tightly against the high-hardness armor layer 311, and the gaps between the armor layers 311 are sealed by the sealing strip 312.

[0052] Because carbon dioxide has a higher thermal expansion rate than air, it compresses the gaps inside the cable, making the cable more compact and reducing the amount of air inside. This results in better internal airtightness and makes the cable less susceptible to damage from compression. Furthermore, the buffer grooves 314 and buffer strips 315 in the outer sheath 313 can better absorb impact forces, providing better protection. Even if the cable catches fire at high temperatures, carbon dioxide will inhibit the combustion process, further preventing the fire from spreading.

[0053] Furthermore, if the cable catches fire at high temperature, the internal temperature will continue to rise. The aluminum hydroxide inside the flame-retardant rubber ring 309 will decompose, absorbing heat and generating water vapor, which will prevent the combustion from proceeding. In addition, the flame-retardant rubber ring 309 will expand, dividing the cable into multiple sections to prevent the fire from spreading and further prevent the occurrence of fire, thus ensuring higher safety.

[0054] Furthermore, during the manufacturing process of the aforementioned cable, the gap between the conductor 1 single filaments is minimized as much as possible, the seal between the armor layer 311 and the outer sheath 313 is maintained, the gap in the armor layer 311 is filled with sealing strip 312, the annular gap between the inner sheath 307 and the cable structure is maintained, the materials also cooperate with each other, and cooperate with the structure after the above-mentioned heating, to obtain better flame retardancy and sealing fire extinguishing effect after combustion.

[0055] Even in the event of a fire, the PVC material product of this invention patent can achieve a light transmittance of ≥50% in the smoke density test. In some chemical plant areas, due to the presence of a large number of chemical components in the environment, it is not possible to use polyolefin materials with better low smoke performance. This technology can meet both the requirements of combustion performance and environmental safety performance of cables.

[0056] During cable laying, when encountering locations requiring bending or frequently bent during use, C-type clips 404 are attached to the bending position of the cable, and spring plates 407 are inserted into support holes 406. End tubes 408 are sleeved at both ends of the spring plates 407. The extension length of the end tubes 408 depends on the curvature of the bend; the larger the curvature, the shorter the extension length of the end tubes 408. The mating grooves 410 and mating holes 411 are aligned, and positioning pins 412 are installed inside to fix the end tubes 408. The connecting screws 415 are rotated to press the anti-slip pads 405 tightly against the outside of the cable, and the C-type clips 404 are fixed. When bending, the rolling rods 409 at the end of the end tubes 408 will roll on the inside of the cable at the bending position, and the spring plates 407 will also fully compress the inside of the cable bend, inhibiting the cable bending and preventing the cable from breaking at low temperatures due to excessive bending, thus better protecting the cable and giving it a longer service life.

[0057] The compression airtight component 3 improves the airtightness of the cable, and the multiple flame-retardant structures better prevent cable problems caused by fire. The bending support component 4 prevents excessive bending during bending through the C-type clip 404 and spring plate 407. At the same time, the liquid in the spiral antifreeze bag 310 also flows during bending, squeezing the internal cable and hindering cable bending. In addition, the outer heat insulation pipe 401 and heat-equalizing layer 403 of the bending support component 4 better prevent low temperature damage to the cable. The two components work together to better protect the cable.

[0058] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A cold-resistant, low-smoke, airtight, explosion-proof low-voltage power cable, comprising a conductor (1), characterized in that: The conductor (1) is wrapped with an inner insulation layer (2) on the outside, and an extrusion airtight assembly (3) is provided on the outside of the inner insulation layer (2). The extrusion airtight assembly (3) includes a central support tube (301). A central support tube (301) is provided between the three inner insulation layers (2). A heat-conducting wire (302) is provided inside the central support tube (301). An air-insulating plate (303) is uniformly sleeved on the outside of the heat-conducting wire (302). A one-way air pipe (304) is installed through the middle of the air-insulating plate (303). A flexible isolation box (305) is uniformly provided on the outside of the central support tube (301). A ventilation hole (306) is provided on the central support tube (301) near the flexible isolation box (305). The inner insulation layer (2) is sleeved with an inner protective layer (307), the inner protective layer (307) is wrapped with an armor layer (311), the gaps of the armor layer (311) are filled with sealing strips (312), the armor layer (311) is wrapped with an outer protective layer (313), and the outer protective layer (313) is uniformly provided with buffer grooves (314) on the side of the outer protective layer (313) near the armor layer (311), and the buffer grooves (314) are filled with buffer strips (315).

2. The cold-resistant, low-smoke, airtight, explosion-proof low-voltage power cable according to claim 1, characterized in that, The inner protective layer (307) is filled with a filling layer (308), and flame-retardant rubber rings (309) are uniformly fitted on the outside of the inner protective layer (307). A spiral antifreeze bag (310) is fitted on one side of the inner protective layer (307) at the flame-retardant rubber rings (309).

3. The cold-resistant, low-smoke, airtight, explosion-proof low-voltage power cable according to claim 1, characterized in that, The flexible isolation box (305) has uniformly opened cavities inside, and the end of the flexible isolation box (305) away from the central support tube (301) contacts the inner side of the inner protective layer (307).

4. The cold-resistant, low-smoke, airtight, explosion-proof low-voltage power cable according to claim 1, characterized in that, The outer side of the middle support tube (301) is composed of several arc-shaped curved surfaces that are attached to the inner insulation layer (2), and the middle support tube (301) is filled with carbon dioxide gas.

5. The cold-resistant, low-smoke, airtight, explosion-proof low-voltage power cable according to claim 2, characterized in that, The inner protective layer (307) has an embedding groove at the location corresponding to the flame-retardant rubber ring (309) and the spiral antifreeze bag (310). The spiral antifreeze bag (310) and the flame-retardant rubber ring (309) are aligned on the outside. The spiral antifreeze bag (310) is filled with antifreeze.

6. The cold-resistant, low-smoke, airtight, explosion-proof low-voltage power cable according to claim 1, characterized in that, The outer protective layer (313) is wrapped with a bending support assembly (4), which includes an outer heat insulation pipe (401). The outer protective layer (313) is wrapped with an outer heat insulation pipe (401), and the outer heat insulation pipe (401) is uniformly provided with embedded support grooves (402). The outer heat insulation pipe (401) is wrapped with a heat equalization layer (403), and C-shaped clips (404) are uniformly sleeved on the outer side of the heat equalization layer (403). Support holes (406) are uniformly provided in the middle of the C-shaped clips (404), and spring plates (407) are installed through the support holes (406). Both ends of the spring plate (407) are fitted with end tubes (408). A rolling rod (409) is rotatably embedded at the end of the end tube (408) away from the spring plate (407). The spring plate (407) is evenly provided with mating grooves (410) corresponding to the end tubes (408). The end tubes (408) are provided with mating holes (411) corresponding to the mating grooves (410). A positioning pin (412) is embedded inside the mating hole (411).

7. The cold-resistant, low-smoke, airtight, explosion-proof low-voltage power cable according to claim 6, characterized in that, The C-type card (404) has anti-slip pads (405) evenly embedded on the side near the outer protective layer (313), and the anti-slip pads (405) are attached to the heat-equalizing layer (403).

8. The cold-resistant, low-smoke, airtight, explosion-proof low-voltage power cable according to claim 6, characterized in that, One end of the C-type clip (404) is welded with a movable end plate (413), and the other end of the C-type clip (404) is welded with a fixed end plate (414). The fixed end plate (414) is symmetrically rotated and mounted with a connecting screw (415). The connecting screw (415) is connected to the movable end plate (413) through a screw hole. A dustproof hose (416) is sleeved on the connecting screw (415) at the position between the movable end plate (413) and the fixed end plate (414).

9. A cold-resistant, low-smoke, airtight, explosion-proof low-voltage power cable according to claim 6, characterized in that, The end tube (408) away from the spring plate (407) has a rounded corner, and the support groove (402) is inlaid with a reinforcing strip (417) on the outside of the heat spreader (403). The rolling rod (409) contacts the reinforcing strip (417).

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