B1-level halogen-free low-smoke flame-retardant temperature-resistant low-voltage power cable
By setting a hole-laden metal shielding layer, buffer layer and armor layer between the insulating layer and the flame retardant layer, the problem of the insulating layer easily deforming at high temperatures of halogen-free low-smoke flame retardant cables is solved, and the mechanical strength and flame retardant capacity of the cable are improved.
Patent Information
- Application Number
- CN202422393274.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-30
- Publication Date
- 2025-07-22
- Estimated Expiration
- 2034-09-30
AI Technical Summary
The existing halogen-free low-smoke flame-retardant low-voltage power cables are prone to deform or break at high temperatures, resulting in a decrease in flame retardant capacity and unable to effectively protect the cables.
A metal shielding layer with holes, a buffer layer and an armor layer are arranged between the insulating layer and the flame retardant layer. The metal shielding layer provides electromagnetic shielding and mechanical protection. The buffer layer serves as a pressure relief channel and the armor layer serves as a barrier to prevent internal pressure from being transmitted to the flame retardant layer and maintains the integrity of the flame retardant layer.
It improves the mechanical strength and flame retardant ability of the cable at high temperatures, prevents the insulating layer from deforming, maintains the structural integrity of the flame retardant layer, and enhances the protective performance of the cable.
Smart Images
Figure CN223140450U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of power cables, in particular to a B1-level halogen-free low-smoke flame-retardant and temperature-resistant low-voltage power cable. Background Art
[0002] Halogen-free low-smoke flame-retardant low-voltage power cables are widely used in occasions with high requirements for safety, environmental protection and temperature resistance. They have the characteristics of being halogen-free, low-smoke, flame-retardant and temperature-resistant, and can provide safe and reliable power supply for high-rise buildings and residences, protect the lives and property safety of residents, and are used in public places such as hospitals, schools, and shopping malls to supply power to facilities, ensuring the normal operation of the power system in case of emergencies.
[0003] Halogen-free low-smoke flame-retardant low-voltage power cables use low-smoke and halogen-free flame-retardant insulating materials as insulating materials to ensure that the amount of smoke generated during combustion is extremely low, improving the visibility at the fire scene. Further, by filling flame-retardant materials, the spread of flames is effectively blocked, reducing the fire risk. In the prior art, the filled flame-retardant materials usually include inorganic flame-retardant materials, such as oxide powders or hydrates. When the cable burns, the flame-retardant materials form a heat-insulating layer to achieve heat insulation and oxygen isolation effects, which can further prevent the spread of flames. However, in this type of cable design, due to the fact that the internal insulating layer will undergo a certain softening effect when heated, causing local water molecules or hydrates in the cable to be heated, the insulating layer will bulge, resulting in deformation or rupture of the heat-insulating layer, weakening the protection ability of the cable or even losing the protection ability, which is not desirable during use. Summary of the Utility Model
[0004] In view of the technical problems existing in the flame-retardant cables in the prior art, the first aspect of the present utility model provides a B1-level halogen-free low-smoke flame-retardant and temperature-resistant low-voltage power cable, comprising:
[0005] A conductor core formed by stranding a plurality of fine copper wires and a water-blocking yarn together is wrapped with a semi-conductive tape to form a cable core with a circular cross-section;
[0006] An insulating layer extruded on the outer wall of the cable core;
[0007] A flame-retardant layer arranged on the outside of the insulating layer;
[0008] A sheath layer extruded on the outer wall of the flame-retardant layer;
[0009] Wherein, an outer shielding layer, a buffer layer and an armor layer are sequentially arranged from inside to outside between the insulating layer and the flame-retardant layer. The outer shielding layer is coated on the outer wall of the insulating layer, the buffer layer is coated on the outer wall of the outer shielding layer, and the armor layer is coated on the outer wall of the buffer layer;
[0010] The outer shielding layer includes a metal shielding layer. The metal shielding layer is provided with holes in its thickness direction, and the buffer layer is provided with a hollow hole structure extending along the axis direction of the cable.
[0011] Preferably, the metal shielding layer includes a copper wire braided net. The braiding angle of the copper wire braided net is 45° to 60°, and the braiding density of the copper wire braided net is greater than 80%.
[0012] Preferably, the metal shielding layer includes a copper tape wrapped layer. The surface of the copper tape is provided with diamond-shaped or circular holes, and the area of the holes on the surface of the copper tape accounts for more than 30% of the total area.
[0013] Preferably, the buffer layer includes an extruded structure layer. The inner wall of the extruded structure layer is provided with grooves extending along the axial direction of the cable, and the hollow hole structure is formed by the grooves.
[0014] Preferably, the extruded structure layer includes a polypropylene extruded layer or a foamed polypropylene extruded layer, and the cross section of the groove is triangular or trapezoidal.
[0015] Preferably, the armor layer includes a longitudinally wrapped copper-plastic composite tape or an aluminum-plastic composite tape.
[0016] Preferably, the flame retardant layer includes a glass ribbon wrapped layer. The number of layers of the glass ribbon wrapped layer is not less than four, and the overlapping rate of the glass ribbon wrapping is 30% - 60%.
[0017] Preferably, the overlapping rate of the glass ribbon wrapping from the inner layer to the outer layer gradually increases.
[0018] Preferably, the conductor core includes a multi-layer fine copper wire stranded structure. The fine copper wire stranded structure includes a four-layer regular stranded structure of 1 + 6 + 12 + 18, and the water blocking yarn is arranged in the gaps between the fine copper wires of each layer.
[0019] Preferably, the thickness of the buffer layer is 1.5 - 2.0 mm.
[0020] Compared with the prior art, the significant advantages of the B1-level halogen-free low-smoke flame retardant and temperature-resistant low-voltage power cable of the present utility model are as follows:
[0021] A shielding layer with holes and an armor layer are sequentially arranged on the outer layer of the polyethylene insulation layer. A buffer layer is arranged between the shielding layer and the armor layer, and the flame retardant layer is arranged on the outer side of the armor layer. The shielding layer can increase the strength of the insulation layer and prevent it from deforming greatly at high temperatures. At the same time, with the buffer layer as the pressure relief channel and the armor layer as the barrier, it can prevent the pressure inside the conductor from being released to the flame retardant layer and causing its deformation. Therefore, the flame retardant layer has higher mechanical strength during the combustion of the cable to maintain its integrity and improve the flame retardant ability of the cable. Description of the Drawings
[0022] The drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component shown in each figure may be denoted by the same reference numeral. For the sake of clarity, not every component is labeled in each figure. Now, embodiments of various aspects of the present invention will be described by way of example and with reference to the drawings.
[0023] Figure 1 is a schematic cross-sectional structure diagram of a Class B1 non-halogen low-smoke flame-retardant heat-resistant low-voltage power cable shown in the present invention.
[0024] Figure 2 is a schematic structure diagram of a Class B1 non-halogen low-smoke flame-retardant heat-resistant low-voltage power cable shown in the present invention. Detailed Embodiments
[0025] For a better understanding of the technical content of the present invention, specific embodiments are given below in conjunction with the accompanying drawings for illustration.
[0026] Combined with Figure 1 and Figure 2 shown, the Class B1 non-halogen low-smoke flame-retardant heat-resistant low-voltage power cable according to an embodiment of the present invention includes a cable core, an insulating layer 4, a flame-retardant layer 8, and a sheath layer 9. The conductor of the cable core is formed by stranding a plurality of fine copper wires.
[0027] In order to improve the axial water-blocking ability of the conductor, water-blocking yarns 2 are arranged in the gaps between the fine copper wires. The conductor core formed by stranding a plurality of fine copper wires 1 and the water-blocking yarns 2 is then wrapped with a semi-conductive tape 3 to form a cable core with a circular cross-section.
[0028] In an alternative embodiment, the conductor core includes a multi-layer fine copper wire stranding structure. The fine copper wire stranding structure includes a four-layer regular stranding structure of 1 + 6 + 12 + 18, and water-blocking yarns 2 are arranged in the gaps between the fine copper wires in each layer.
[0029] Specifically, at least one water-blocking yarn 2 is arranged between the first and second layer structures, at least one water-blocking yarn is arranged between the second and third layer structures, at least one water-blocking yarn is arranged between the third and fourth layer structures, and one water-blocking yarn is arranged between the fourth layer structure and the insulating layer 4. The winding pitch diameter ratio of the water-blocking yarn is smaller than the stranding pitch diameter ratio of the fine copper wires. Therefore, a closed area surrounded by one water-blocking yarn is formed between every two layer structures, achieving the purpose of axial water-blocking.
[0030] Furthermore, the insulating layer 4 is extruded on the outer wall of the cable core. The insulating layer 4 can be a cross-linked polyethylene insulating layer. The cross-linked polyethylene insulating layer has excellent heat resistance. Its long-term allowable operating temperature can reach 90°C, and it can withstand the instantaneous high temperature during a short circuit, with a temperature range of 170 - 250°C.
[0031] Thus, the cross-linked polyethylene insulation layer can still maintain stable electrical performance under high-temperature environments, thereby improving the overload capacity and short-circuit current withstand capacity of the cable.
[0032] Further, a flame-retardant layer 8 is provided on the outer side of the insulation layer 4. The flame-retardant layer 8 provides flame-retardant performance for the cable, especially effectively preventing the spread of fire and preventing the cable from generating non-diffusing open flames.
[0033] In an alternative embodiment, the flame-retardant layer 8 includes a glass ribbon winding layer. The number of layers of the glass ribbon winding layer is not less than four, and the winding overlap rate of the glass ribbon is between 30% and 60%.
[0034] Preferably, the winding overlap rate of the glass ribbon gradually increases from the inner layer to the outer layer. In this way, a tight glass fiber winding structure can be formed. When a fire breaks out outside the cable or a conductor short-circuits and catches fire, the glass ribbon winding layer can maintain a stable shape at high temperatures by virtue of its high-temperature resistance in this application and form a heat-insulating barrier.
[0035] In other embodiments, the flame-retardant layer 8 can also use a ceramized silicone rubber or a ceramized polyolefin flame-retardant layer.
[0036] Further, a sheath layer 9 is extruded on the outer wall of the flame-retardant layer 8. The sheath layer 9 uses a B1-level low-smoke and halogen-free flame-retardant polyolefin sheath.
[0037] Among them, an outer shielding layer 5, a buffer layer 6, and an armor layer 7 are sequentially arranged from the inside to the outside between the insulation layer 4 and the flame-retardant layer 8. The outer shielding layer 5 is coated on the outer wall of the insulation layer 4, the buffer layer 6 is coated on the outer wall of the outer shielding layer 5, and the armor layer 7 is coated on the outer wall of the buffer layer 6.
[0038] The outer shielding layer 5 includes a metal shielding layer. The metal shielding layer is provided with holes in its thickness direction, and the buffer layer 6 is provided with a hollow hole structure extending along the axial direction of the cable.
[0039] In this way, the metal shielding layer can play a role in electromagnetic shielding and mechanical protection for the insulation layer 4, and can reduce the deformation of the insulation layer at high temperatures. In particular, the water vapor in the conductor will not cause large-scale deformation of the insulation layer after being heated.
[0040] In an alternative embodiment, the metal shielding layer includes a copper wire braided mesh. The braiding angle of the copper wire braided mesh is 45° to 60°, and the braiding density of the copper wire braided mesh is greater than 80%.
[0041] In other embodiments, the metal shielding layer includes a copper tape winding layer. The surface of the copper tape is provided with diamond-shaped or circular holes. The area of the holes on the surface of the copper tape accounts for more than 30% of the total area, and the winding overlap rate of the copper tape is about 10%.
[0042] Further, the buffer layer 6 includes an extruded structure layer. The inner wall of the extruded structure layer is provided with grooves 61 extending along the axial direction of the cable, and the hollow hole structure is formed by the grooves 61. In this way, the grooves 61 form a release space for the internal pressure of the cable to avoid the deformation and rupture of the flame retardant layer 8 caused by the internal pressure.
[0043] In an alternative embodiment, the extruded structure layer includes a polypropylene extrusion layer or a foamed polypropylene extrusion layer, and the cross-section of the groove 61 is triangular or trapezoidal.
[0044] Specifically, when extruding the polypropylene extrusion layer, by setting the shape of the die head, the inner layer of the extruded structure is formed with grooves 61, and the number of grooves 61 can be selected from 2 to 3.
[0045] Further, in order to make the groove 61 a pressure relief channel for the gas in the conductor and quickly reduce the pressure inside the inner layer of the insulating layer, the thickness of the buffer layer 6 is set to 1.5 - 2.0 mm, and the depth of the groove 61 is half of the thickness of the buffer layer 6.
[0046] Further, in order to prevent the pressure from leaking to the flame retardant layer 8, the armor layer 7 includes a longitudinally wrapped copper-plastic composite tape or an aluminum-plastic composite tape. Through the longitudinally wrapped copper-plastic or aluminum-plastic composite tape, a metal shielding shell is formed on the outer layer of the buffer layer 6, which improves the mechanical strength of the cable while improving the flame retardant performance, especially the mechanical strength of the flame retardant layer 8 in the molten or charred shell state. Maintaining the structural integrity of the flame retardant layer 8 is beneficial to maintaining the flame retardant ability of the cable.
[0047] Combining the above embodiments, the utility model sequentially arranges a perforated shielding layer and an armor layer on the outer layer of the polyethylene insulating layer, a buffer layer is arranged between the shielding layer and the armor layer, and the flame retardant layer is arranged on the outer side of the armor layer. The shielding layer can increase the strength of the insulating layer and avoid large deformation at high temperatures. At the same time, with the buffer layer as the pressure relief channel and the armor layer as the barrier, it can prevent the pressure inside the conductor from being released to the flame retardant layer and causing its deformation. Therefore, the flame retardant layer has higher mechanical strength during cable combustion to maintain its integrity and improve the flame retardant ability of the cable.
[0048] Although the present utility model has been disclosed above with preferred embodiments, it is not intended to limit the present utility model. Those with ordinary knowledge in the technical field to which the present utility model belongs can make various changes and modifications without departing from the spirit and scope of the present utility model. Therefore, the protection scope of the present utility model shall be subject to what is defined by the claims.
Claims
1. A Class B1 halogen-free low-smoke flame-retardant and heat-resistant low-voltage power cable, characterized in that, Comprising: A conductor core formed by stranding multiple fine copper wires (1) and a water-blocking yarn (2) is wrapped with a semi-conductive wrapping tape (3) to form a cable core with a circular cross-section; An insulating layer (4) extruded on the outer wall of the cable core; A flame-retardant layer (8) provided on the outer side of the insulating layer (4); A sheath layer (9) extruded on the outer wall of the flame-retardant layer (8); Wherein, an outer shielding layer (5), a buffer layer (6) and an armor layer (7) are sequentially arranged from the inside to the outside between the insulating layer (4) and the flame-retardant layer (8). The outer shielding layer (5) covers the outer wall of the insulating layer (4), the buffer layer (6) covers the outer wall of the outer shielding layer (5), and the armor layer (7) covers the outer wall of the buffer layer (6); The outer shielding layer (5) includes a metal shielding layer. The metal shielding layer is provided with holes in its thickness direction, and the buffer layer (6) is provided with a hollow hole structure extending along the axial direction of the cable.
2. The B1-class halogen-free low-smoke flame-retardant and temperature-resistant low-voltage power cable according to claim 1, wherein The metal shielding layer includes a copper wire braided mesh. The braiding angle of the copper wire braided mesh is 45° - 60°, and the braiding density of the copper wire braided mesh is greater than 80%.
3. The B1-class halogen-free low-smoke flame-retardant and temperature-resistant low-voltage power cable according to claim 1, characterized in that, The metal shielding layer includes a copper tape wrapped layer. The surface of the copper tape is provided with diamond-shaped or circular holes, and the area of the holes on the surface of the copper tape accounts for more than 30% of the total area.
4. The B1 - level halogen - free low - smoke flame - retardant and temperature - resistant low - voltage power cable according to claim 1, characterized in that, The buffer layer (6) includes an extruded structure layer. The inner wall of the extruded structure layer is provided with a groove (61) extending along the axial direction of the cable, and the hollow hole structure is formed by the groove (61).
5. The Class B1 non-halogen low-smoke flame-retardant and temperature-resistant low-voltage power cable according to claim 4, wherein The extruded structure layer includes a polypropylene extruded layer or a foamed polypropylene extruded layer, and the cross-section of the groove (61) is triangular or trapezoidal.
6. The B1-class halogen-free low-smoke flame-retardant and temperature-resistant low-voltage power cable according to claim 1, characterized in that, The armor layer (7) includes a longitudinally wrapped copper-plastic composite tape or an aluminum-plastic composite tape.
7. The Class B1 non-halogen low-smoke flame-retardant and temperature-resistant low-voltage power cable according to claim 1, characterized in that, The flame-retardant layer (8) includes a glass fiber tape wrapped layer. The number of layers of the glass fiber tape wrapped layer is not less than four, and the wrapping overlap rate of the glass fiber tape is 30% - 60%.
8. The B1-class halogen-free low-smoke flame-retardant and temperature-resistant low-voltage power cable according to claim 7, characterized in that, The wrapping overlap rate of the glass fiber tape gradually increases from the inner layer to the outer layer.
9. The B1-class halogen-free low-smoke flame-retardant and temperature-resistant low-voltage power cable according to claim 1, wherein, The conductor core includes a multi-layer fine copper wire stranding structure. The fine copper wire stranding structure includes a four-layer regular stranding structure of 1 + 6 + 12 + 18, and the water-blocking yarn (2) is provided in the gaps between the fine copper wires in each layer.
10. The B1-class halogen-free low-smoke flame-retardant and heat-resistant low-voltage power cable according to any one of claims 1-9, characterized in that, The thickness of the buffer layer (6) is 1.5 - 2.0 mm.