A heat-resistant flame-retardant crosslinked polyethylene insulated cable

Abstract

The application relates to the technical field of insulated cables, and discloses a heat-resistant and flame-retardant crosslinked polyethylene insulated cable which comprises a plurality of metal conductors wrapped with crosslinked polyethylene insulation layers, the outer sides of the plurality of metal conductors are sequentially provided with a semiconductor shielding layer, a metal shielding layer and a sheath, and the heat-resistant and flame-retardant crosslinked polyethylene insulated cable further comprises mounting ring frames, rotating ring frames, conductor fastening assemblies and insulation sleeves, the mounting ring frames are arranged on the outer walls of the sheaths and are provided in plurality, a spiral connecting assembly is arranged between every two adjacent rotating ring frames, a spiral connecting assembly is also arranged between the rotating ring frame located on one side and the mounting ring frame, the conductor fastening assembly is arranged in each rotating ring frame, the insulation sleeve is communicated with each rotating ring frame, and the conductor flame-retardant assembly is arranged in the insulation sleeve. Through the technical scheme, the problem that the crosslinked polyethylene insulated cable lacks sufficient flame retardance and heat resistance when being electrically connected with the wiring port of the power equipment in the prior art is solved.

Description

Technical Field

[0001] This invention relates to the field of insulated cable technology, and more specifically, to a heat-resistant and flame-retardant cross-linked polyethylene insulated cable. Background Technology

[0002] Cross-linked polyethylene (XLPE) insulated cables are common power transmission devices in existing power grids. During the production of XLPE insulated cables, the polyethylene material is processed using cross-linking technology. This process transforms the polyethylene insulation material wrapped around the cable conductor into a three-dimensional network structure. Because the cross-linked polyethylene insulation material possesses excellent heat resistance, the resulting XLPE insulated cables also exhibit good heat resistance during use. During the wrapping process, flame-retardant filler material is added to the outside of the multiple cross-linked polyethylene layers on the cable conductor. This flame-retardant filler material, combined with the high-temperature resistant XLPE insulation, achieves the flame-retardant properties of the XLPE insulated cable.

[0003] However, in existing technologies, when using cross-linked polyethylene (XLPE) insulated cables to make electrical connections with different terminals on power equipment, it is generally necessary to peel off multiple cable conductors wrapped with XLPE layers from between the semiconductor shielding layer, the metal shielding layer, and the sheath. At this time, there is no flame-retardant filler material on the outside of the peeled cable conductor area. In the event of an open flame, it is easy to cause the XLPE insulation layer to burn and damage the metal conductors. In addition, during the use of XLPE insulated cables, when a short circuit fault occurs in the power grid, the XLPE insulated cable will generate a large temperature in a short time. Because multiple metal conductors are densely arranged when connected to the terminal of the power equipment, it is not convenient for the heat to dissipate quickly. Summary of the Invention

[0004] This invention proposes a heat-resistant and flame-retardant cross-linked polyethylene insulated cable, which solves the problem that existing cross-linked polyethylene insulated cables lack sufficient flame retardancy and heat resistance when actually connected to the wiring ports of power equipment.

[0005] The technical solution of the present invention is as follows: A heat-resistant and flame-retardant cross-linked polyethylene insulated cable includes multiple metal conductors wrapped with cross-linked polyethylene insulation layers, and a semiconductor shielding layer, a metal shielding layer, and a sheath are sequentially disposed on the outer sides of the multiple metal conductors, and further includes:

[0006] The mounting ring frame is disposed on the outer wall of the sheath;

[0007] Multiple rotating ring frames are provided, and a spiral connection assembly is provided between two adjacent rotating ring frames. The spiral connection assembly is also provided between the rotating ring frame on one side and the mounting ring frame.

[0008] Conductor fastening assembly, wherein each of the rotating ring frames is provided with the conductor fastening assembly;

[0009] An insulating sleeve is connected to each of the rotating ring frames. A conductor flame-retardant component is provided inside the insulating sleeve, and the metal conductor passes through the corresponding insulating sleeve.

[0010] To ensure a close fit between the mounting ring frame and the sheath, the inner arc surface of the mounting ring frame is provided with a groove, and a flexible friction ring is provided in the groove. The inner wall of the flexible friction ring is in contact with the outer wall of the sheath.

[0011] To keep the mounting ring frame fixed on the surface of the sheath, the mounting ring frame has multiple extrusion protrusions connected to its side wall. Each extrusion protrusion has a through groove, and fastening grooves are provided on both sides of the extrusion protrusion. A metal fastening plate is slidably disposed between two of the fastening grooves. The metal fastening plate is in contact with the outer wall of the sheath, and an extrusion pellet is provided at the bottom of the metal fastening plate.

[0012] To connect the mounting ring frame and multiple rotating ring frames together and adjust the orientation of the insulating sleeve, the spiral connection assembly further includes a threaded sleeve seat and an internal threaded sleeve. The mounting ring frame and one side of the multiple rotating ring frames located in the middle are connected to the threaded sleeve seat, and each rotating ring frame is connected to the internal threaded sleeve, which is threadedly connected to the corresponding threaded sleeve seat.

[0013] To guide the metal conductor to move in the corresponding direction within the rotating ring frame, the conductor fastening assembly further includes a short conductor fastening frame and a long conductor fastening frame. The short conductor fastening frame is fixedly connected within the rotating ring frame and is located within the rotating ring frame near the insulating sleeve. The long conductor fastening frame is fixedly connected within the rotating ring frame and has multiple conductor removal holes.

[0014] To further improve the heat resistance of the metal conductor, the insulating sleeve includes a connecting interface, a plastic bending section, and a guide section. The connecting interface is connected to the rotating ring frame and corresponds to the short conductor fastening frame. The plastic bending section is connected to the connecting interface, and the guide section is connected to one side of the plastic bending section.

[0015] To further improve the flame retardancy of the conductor, the flame retardant component includes a flame retardant filling cylinder layer, a metal fastening wire, and a connecting ring sleeve. The flame retardant filling cylinder layer is disposed between the inner wall of the connecting interface, the plastic bending cylinder section, and the guide cylinder section. The metal fastening wire is spirally disposed on the outer arc surface of the flame retardant filling cylinder layer. The metal fastening wire is fixedly connected to the inner wall of the connecting interface through a connecting ring. One side of the guide cylinder section is connected to the connecting ring sleeve, and one side of the metal fastening wire penetrates through the connecting ring sleeve.

[0016] In order to bring out the metal conductors other than those from the insulating sleeve, a conical cable outlet tube is further connected to the rotating ring frame on the side furthest from the mounting ring frame.

[0017] The working principle and beneficial effects of this invention are as follows:

[0018] In this invention, when it is necessary to electrically connect a cross-linked polyethylene insulated cable to the wiring port of a power equipment, because the multiple wiring ports of the power equipment are relatively dispersed, it is necessary to peel off a section of the sheath, metal isolation layer, semiconductor isolation layer, and flame-retardant filler on the cross-linked polyethylene insulated cable. The length of the peeled area is based on the distance from the wiring port furthest from the metal conductor. Then, the mounting ring frame is fixed to the outside of the sheath, and a rotating ring frame is threaded onto one side of the mounting ring frame. Multiple metal conductors are moved into the short conductor fastening frame and the long conductor fastening frame respectively. The metal conductor in the short conductor fastening frame is removed through the insulating sleeve, and then the next rotating ring frame is threaded onto the rotating ring frame. The remaining multiple metal conductors are then passed sequentially through the short conductor fastening frame and the long conductor fastening frame. The metal conductors within the short conductor fastening frame are then moved into the insulating sleeve. Using this method, each of the multiple metal conductors is led out through a conical outlet tube and multiple insulating sleeves, allowing them to be electrically connected to multiple terminals. This invention avoids heat accumulation during current transmission by dispersing the multiple metal conductors, effectively improving the heat resistance and heat dissipation of the cross-linked polyethylene insulated cable. Furthermore, the effective flame retardant treatment of each metal conductor enhances the flame retardancy of the cross-linked polyethylene insulated cable, reducing damage to the cable in the event of a fire. Attached Figure Description

[0019] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0020] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0021] Figure 2 This is a partial cross-sectional view of the present invention;

[0022] Figure 3 This is a schematic diagram of the structure of the mounting ring frame, flexible friction ring, and extrusion protrusion in this invention;

[0023] Figure 4 This is a partial cross-sectional structural diagram of the mounting ring frame, flexible friction ring, extrusion protrusion, and metal fastening plate in this invention.

[0024] Figure 5 For the present invention Figure 4 A magnified structural diagram of point A in the middle;

[0025] Figure 6 This is a schematic diagram of the cross-linked polyethylene insulation layer, metal conductor, semiconductor shielding layer, metal shielding layer, and sheath in this invention.

[0026] Figure 7 This is a schematic diagram of the structure of the rotating ring frame, insulating sleeve, conductor fastening assembly, and conductor flame-retardant assembly in this invention.

[0027] In the diagram: 1. Cross-linked polyethylene insulation layer; 2. Metal conductor; 3. Semiconductor shielding layer; 4. Metal shielding layer; 5. Sheath; 6. Mounting ring frame; 7. Rotating ring frame; 8. Insulating sleeve; 9. Flexible friction ring; 10. Extrusion protrusion; 11. Through groove; 12. Fastening groove; 13. Metal fastening plate; 14. Extrusion granule; 15. Threaded sleeve seat; 16. Internal threaded sleeve; 17. Short conductor fastening frame; 18. Long conductor fastening frame; 19. Connecting interface; 20. Plastic bending cylinder section; 21. Guide cylinder section; 22. Flame-retardant filling cylinder layer; 23. Metal fastening wire; 24. Connecting ring sleeve; 25. Conical outlet cylinder. Detailed Implementation

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0029] like Figures 1 to 7As shown, this embodiment proposes a heat-resistant and flame-retardant cross-linked polyethylene insulated cable, including multiple metal conductors 2 wrapped with cross-linked polyethylene insulation layers 1. A semiconductor shielding layer 3, a metal shielding layer 4, and a sheath 5 are sequentially disposed on the outer sides of the multiple metal conductors 2. The metal conductors 2 are generally made of aluminum or copper and are used for conducting current. The cross-linked polyethylene insulation layer 1 is a representative structure of cross-linked polyethylene insulated cables. After being processed by the cross-linking process, the polyethylene insulation layer has good heat resistance. Both the semiconductor shielding layer 3 and the metal shielding layer 4 wrap the multiple metal conductors 2 and the flame-retardant filler material. The semiconductor shielding layer 3 and the metal shielding layer 4 have the function of balancing the electric field and providing electromagnetic shielding. The sheath 5 is usually made of polyethylene or polyvinyl chloride and is used to protect the semiconductor shielding layer 3, the metal shielding layer 4, and the multiple metal conductors 2. The above structures are common components of cross-linked polyethylene insulated cables in the prior art and are known to those skilled in the art.

[0030] like Figures 1 to 5 As shown, it also includes an installation ring frame 6, which is set on the outer wall of the sheath 5. The inner arc surface of the installation ring frame 6 has a groove, and a flexible friction ring 9 is set in the groove. The inner wall of the flexible friction ring 9 is in contact with the outer wall of the sheath 5. When it is necessary to make an electrical connection between the cross-linked polyethylene insulated cable and the wiring port of the power equipment, because the multiple wiring ports of the power equipment are relatively dispersed, it is necessary to peel off a section of the sheath 5, metal isolation layer, semiconductor isolation layer and flame retardant filler on the cross-linked polyethylene insulated cable. The length of the peeled area is based on the distance from the wiring port farthest from the metal conductor 2. The installation ring frame 6 is fixed to the cut-off point of the sheath 5, metal isolation layer, semiconductor isolation layer and flame retardant filler on the cross-linked polyethylene insulated cable, so that the flexible friction ring 9 contacts and fits tightly with the outer wall of the sheath 5, preventing the sheath 5, metal isolation layer, semiconductor isolation layer and flame retardant filler from becoming loose. The inner arc surface of the flexible friction ring 9 is provided with a friction end face. After the friction end face contacts the surface of the sheath 5, the installation ring frame 6 is not easy to move from the surface of the sheath 5.

[0031] Multiple extrusion protrusions 10 are connected to the side wall of the mounting ring frame 6. A through groove 11 is opened in the extrusion protrusion 10. Fastening grooves 12 are opened on both sides of the extrusion protrusion 10. A metal fastening piece 13 is slidably arranged between the two fastening grooves 12. The metal fastening piece 13 is in contact with the outer wall of the sheath 5. An extrusion granule 14 is provided at the bottom of the metal fastening piece 13. After the mounting ring frame 6 is fixed to the outer surface of the sheath 5, a screwdriver or other object is used to push the metal fastening piece 13 towards the inner arc surface of the mounting ring frame 6 through the through groove 11. This causes the extrusion granule 14 to cause the surface of the flexible sheath 5 to be recessed inward, thus fitting the metal fastening piece 13 into the sheath 5 and fixing the mounting ring frame 6 to the surface of the sheath 5.

[0032] like Figures 1 to 2 and Figure 7 As shown, there are multiple rotating ring frames 7. A helical connection assembly is provided between two adjacent rotating ring frames 7. A helical connection assembly is also provided between a rotating ring frame 7 on one side and a mounting ring frame 6. The helical connection assembly includes a threaded sleeve 15 and an internal threaded sleeve 16. The mounting ring frame 6 and one side of the multiple rotating ring frames 7 in the middle are all connected to the threaded sleeve 15. Each rotating ring frame 7 is connected to an internal threaded sleeve 16, which is threadedly connected to the corresponding threaded sleeve 15. First, the rotating ring with the most conductor removal holes on the internal long conductor fastening frame 18 is... The frame 7 is connected to one side of the mounting ring frame 6. After the internal threaded sleeve 16 is threadedly connected to the threaded cylinder seat 15, the ring frame 7 is rotated so that the internal threaded sleeve 16 is gradually fitted onto the surface of the threaded cylinder seat 15. The method of connecting the internal threaded sleeve 16 to the threaded cylinder seat 15 not only allows for detachable connection between the rotating ring frame 7 and the mounting ring frame 6, or even between multiple rotating ring frames 7, facilitating the operation of the metal conductor 2, but also allows for adjustment of the orientation angle of the insulating sleeve 8 on the rotating ring frame 7. Furthermore, a friction ring sleeve is fitted on the outer wall of the rotating ring frame 7, making it easy to pick up and rotate the rotating ring frame 7.

[0033] Each rotating ring 7 is equipped with a conductor fastening assembly, which includes a short conductor fastening frame 17 and a long conductor fastening frame 18. The short conductor fastening frame 17 is fixedly connected inside the rotating ring 7 and is located near the insulating sleeve 8. The long conductor fastening frame 18 is fixedly connected inside the rotating ring 7 and has multiple conductor removal holes. According to the correspondence between the corresponding metal conductor 2 and the wiring port of the power equipment, the metal conductor 2 is moved into the short conductor fastening frame 17. After the metal conductor 2 passes through the insulating sleeve 8, it drives the rotating ring 7 to rotate, moving the insulating sleeve 8 and the metal conductor 2 to the side of the wiring port of the power equipment, so that the metal conductor 2 is electrically connected to the wiring port of the power equipment. The number of metal conductors 2 transported by the long conductor fastening frame 18 in different rotating ring 7 is reduced. The volume of the long conductor fastening frame 18 is reduced, and the number of conductor removal holes is significantly reduced.

[0034] Each rotating ring frame 7 is connected to an insulating sleeve 8. The insulating sleeve 8 includes a connecting interface 19, a plastic bending section 20, and a guide section 21. The connecting interface 19 is connected to the rotating ring frame 7 and corresponds to the short conductor fastening frame 17. The plastic bending section 20 is connected to the connecting interface 19. The guide section 21 is connected to one side of the plastic bending section 20. The connecting interface 19 is used to connect to the rotating ring frame 7 at an angle. One end of the connecting interface 19 faces the connection direction of the metal conductor 2. The plastic bending section 20 can be bent, and after bending the plastic bending section 20, the plastic bending section 20 will not produce a deformation recovery phenomenon. The plastic bending section 20 is bent so that the guide section 21 faces the wiring port of the power equipment. Regardless of the number of metal conductors 2 set inside the rotating ring frame 7, the rotating ring frame 7 has sufficient internal area to facilitate the full dissipation of heat generated during the transmission of current by the metal conductor 2.

[0035] It should be further explained that the insulating sleeve 8 is also made of cross-linked polyethylene, which also has good insulation and heat resistance. By presenting a relatively dispersed guiding installation method among the multiple metal conductors 2, it can further prevent the problem of heat accumulation caused by the internal heating of the multiple metal conductors 2 when transmitting current or encountering current short circuit faults. In addition, if one of the metal conductors 2 is subsequently affected by a fire, the other metal conductors 2 will not be directly damaged by open flame.

[0036] An insulating sleeve 8 contains a flame-retardant conductor assembly. A metal conductor 2 passes through the corresponding insulating sleeve 8. The flame-retardant conductor assembly includes a flame-retardant filling cylinder layer 22, a metal fastening wire 23, and a connecting ring sleeve 24. The flame-retardant filling cylinder layer 22 is disposed between the inner walls of the connecting interface 19, the plastic bending cylinder section 20, and the guide cylinder section 21. The metal fastening wire 23 is spirally disposed on the outer arc surface of the flame-retardant filling cylinder layer 22. The metal fastening wire 23 is fixedly connected to the inner wall of the connecting interface 19 via a connecting ring. One side of the guide cylinder section 21 is connected to the connecting ring sleeve 24, and one side of the metal fastening wire 23 passes through the connecting ring sleeve 24. After the metal conductor 2 passes through the insulating sleeve 8, the outer wall of the metal conductor 2, which is wrapped with a cross-linked polyethylene insulation layer 1, contacts the outer wall of the flame-retardant filling cylinder layer 22. Then, the metal fastening wire 23 is pulled from the connecting ring. The portion removed from the sleeve 24 causes the metal fastening wire 23 to tighten within the insulating sleeve 8. Then, the metal fastening wire 23 presses against the flame-retardant filling layer 22 and contacts the outer wall of the cross-linked polyethylene insulation layer 1 of the metal conductor 2. This ensures that the area of ​​the flame-retardant filling layer 22 pressed by the metal fastening wire 23 is tightly bonded to the cross-linked polyethylene insulation layer 1 on the outside of the metal conductor 2, isolating airflow between the flame-retardant filling layer 22 and the metal conductor 2. When exposed to open flame, the insulating sleeve 8's excellent heat resistance prevents the open flame from directly damaging the metal conductor 2. Furthermore, the flame-retardant filling layer 22 effectively retards the open flame when exposed to it, preventing its spread on the metal conductor 2 and isolating the metal conductor 2 from the air inside the flame-retardant filling layer 22, thus preventing the open flame from burning within the insulating sleeve 8.

[0037] A conical cable outlet cylinder 25 is connected to the rotating ring 7 on the side furthest from the installation ring 6. After multiple metal conductors 2 are moved out through the insulating sleeve 8 in sequence, the last remaining metal conductor 2 is moved out through the conical cable outlet cylinder 25, so that the metal conductor 2 determines the direction of the entire cross-linked polyethylene insulation. Then, the metal conductor 2 is electrically connected to the wiring port of the power equipment.

[0038] The working principle of this heat-resistant and flame-retardant cross-linked polyethylene insulated cable:

[0039] When it is necessary to electrically connect a cross-linked polyethylene (XLPE) insulated cable to the wiring ports of power equipment, because the multiple wiring ports of the power equipment are relatively dispersed, it is necessary to strip a section of the sheath 5, metal isolation layer, semiconductor isolation layer, and flame-retardant filler on the XLPE insulated cable. The length of the stripped area is based on the distance from the wiring port furthest from the metal conductor 2. Then, the mounting ring 6 is fixed to the outside of the sheath 5, and a rotating ring 7 is threaded onto one side of the mounting ring 6. The multiple metal conductors 2 are then moved to the short conductor fastening frame 17 respectively. Within the long conductor fastening frame 18, the metal conductor 2 within the short conductor fastening frame 17 is removed through the insulating sleeve 8. Then, the next rotating ring frame 7 is threaded onto the rotating ring frame 7. The remaining multiple metal conductors 2 continue to pass sequentially through the short conductor fastening frame 17 and the long conductor fastening frame 18. The metal conductors 2 within the short conductor fastening frame 17 are then moved into the insulating sleeve 8. Using the above method, the multiple metal conductors 2 are each led out through the tapered lead-out cylinder 25 and the multiple insulating sleeves 8, so that the multiple metal conductors 2 can be distributed and electrically connected to multiple wiring ports.

[0040] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. 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 heat-resistant and flame-retardant cross-linked polyethylene insulated cable, comprising a plurality of metal conductors (2) wrapped with a cross-linked polyethylene insulation layer (1), wherein a semiconductor shielding layer (3), a metal shielding layer (4), and a sheath (5) are sequentially disposed on the outer sides of the plurality of metal conductors (2), characterized in that, Also includes: Mounting ring frame (6), the mounting ring frame (6) is disposed on the outer wall of the sheath (5); Rotating ring frames (7) are provided in multiple quantities. A spiral connection assembly is provided between two adjacent rotating ring frames (7). The spiral connection assembly is also provided between the rotating ring frame (7) on one side and the mounting ring frame (6). Conductor fastening assembly, each of the rotating ring frames (7) is provided with the conductor fastening assembly; Insulating sleeve (8), each of the rotating ring frames (7) is connected to the insulating sleeve (8), the insulating sleeve (8) is provided with a conductor flame retardant component, and the metal conductor (2) passes through the corresponding insulating sleeve (8). The conductor fastening assembly includes: A short conductor fastening frame (17) is fixedly connected inside the rotating ring frame (7). The short conductor fastening frame (17) is located inside the rotating ring frame (7) at a position close to the insulating sleeve (8). Long conductor fastening frame (18), the long conductor fastening frame (18) is fixedly connected inside the rotating ring frame (7), and the long conductor fastening frame (18) is provided with multiple conductor removal holes; The insulating sleeve (8) includes: A connecting interface (19) is connected to the rotating ring frame (7), and the connecting interface (19) corresponds to the short conductor fastening frame (17); Plastic bending cylinder section (20), the plastic bending cylinder section (20) is connected to the connecting interface (19); Guide tube section (21), one side of the plastic bending tube section (20) is connected to the guide tube section (21). The conductor flame-retardant component includes: Flame-retardant filling cylinder layer (22) is disposed between the inner wall of the connecting interface (19), the plastic bending cylinder section (20) and the guide cylinder section (21); Metal fastening wire (23) is spirally arranged on the outer arc surface of the flame-retardant filling cylinder layer (22), and the metal fastening wire (23) is fixedly connected to the inner wall of the connecting interface (19) through a connecting ring; A connecting ring sleeve (24) is connected to one side of the guide tube section (21), and one side of the metal fastening wire (23) passes through the connecting ring sleeve (24).

2. The heat-resistant and flame-retardant cross-linked polyethylene insulated cable according to claim 1, characterized in that, The inner arc surface of the mounting ring frame (6) is provided with a groove, and a flexible friction ring (9) is provided in the groove. The inner wall of the flexible friction ring (9) is in contact with the outer wall of the sheath (5).

3. The heat-resistant and flame-retardant cross-linked polyethylene insulated cable according to claim 2, characterized in that, The side wall of the mounting ring (6) is connected to a plurality of extrusion protrusions (10), and a through groove (11) is provided in the extrusion protrusion (10). Fastening grooves (12) are provided on both sides of the extrusion protrusion (10). A metal fastening plate (13) is slidably arranged between the two fastening grooves (12). The metal fastening plate (13) is in contact with the outer wall of the sheath (5). An extrusion pellet (14) is provided at the bottom of the metal fastening plate (13).

4. The heat-resistant and flame-retardant cross-linked polyethylene insulated cable according to claim 3, characterized in that, The spiral connection assembly includes: The threaded sleeve seat (15) is connected to one side of the mounting ring frame (6) and one side of the plurality of rotating ring frames (7) located in the middle. An internal threaded sleeve (16) is connected to each of the rotating ring frames (7), and the internal threaded sleeve (16) is threadedly connected to the corresponding threaded sleeve seat (15).

5. The heat-resistant and flame-retardant cross-linked polyethylene insulated cable according to claim 4, characterized in that, A conical cable outlet tube (25) is connected to the rotating ring frame (7) on the side furthest from the mounting ring frame (6).

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