Flame-retardant B1-level environmentally friendly power cable

Abstract

The present invention relates to the technical field of power cables, and in particular to a flame-retardant B1-class environmental protection power cable, which includes a cable core, an armor layer, a flame-retardant layer, and an outer sheath distributed from the inside to the outside along the conductor cross-section; wherein, the armor layer includes a steel wire mesh structure, and a microporous structure is formed between the steel wire mesh structures, the flame-retardant layer includes a hydrogel powder layer, a water-soluble film, a flame-retardant powder layer, and a glass ribbon layer distributed from the inside to the outside, and the hydrogel powder layer includes a first part in the microporous structure and a second part outside the cross-section of the armor layer. In the present invention, a flame-retardant layer is arranged on the outer layer of the armor layer, and the flame-retardant layer combines hydrogel powder and a flame-retardant powder that decomposes water when heated. After the cable is heated, the water decomposed from the flame-retardant powder combines with the hydrogel powder to form a hard shell, preventing the flame from penetrating inward continuously, protecting the internal cable structure, and avoiding electrical circuit failures.

Description

Technical Field

[0001] The present invention relates to the technical field of power cables, and particularly to a flame-retardant B1-class environmentally friendly power cable. Background Art

[0002] Currently, B1-class cables usually use low-smoke and halogen-free materials for flame retardancy. The low-smoke and halogen-free materials are thermoplastic elastomer materials. When burning, they only produce a small amount of smoke and do not release toxic gases. Therefore, they have the characteristics of low-smoke environmental protection. They are suitable for being installed in crowded places such as fire corridors and shopping malls. At the same time, the low-smoke and halogen-free materials have the characteristics of high temperature resistance, oxidation resistance, non-flammability, high oxygen index, and self-extinguishing.

[0003] However, when the flame temperature is high and continuous, the low-smoke and halogen-free type still does not have high fire resistance. Therefore, the method of winding with fiberglass tape is usually used to improve the flame retardancy. Once the fiberglass tape melts and drips, it is very easy to expose the internal cable structure and cause the line to be burned through. Summary of the Invention

[0004] The present invention provides a flame-retardant B1-class environmentally friendly power cable, which includes a cable core, an armor layer, a flame-retardant layer, and an outer sheath distributed from the inside to the outside along the conductor cross-section;

[0005] Among them, the armor layer includes a steel wire mesh structure, and a microporous structure is formed between the steel wire mesh structures. The flame-retardant layer includes a water-setting powder layer, a water-soluble film, a flame-retardant powder layer, and a fiberglass tape layer distributed from the inside to the outside. The water-setting powder layer includes a first part in the microporous structure and a second part outside the cross-section of the armor layer. The flame-retardant powder layer is arranged to release water when heated, so that the water-setting powder layer forms a hard shell.

[0006] Preferably, the water-setting powder layer includes inorganic water-setting powder, and the inorganic water-setting powder is coated and solidified by the water-soluble film.

[0007] Preferably, the inorganic water-setting powder includes sulfoaluminate cement powder.

[0008] Preferably, the flame-retardant powder layer includes water-saturated resin powder or aluminum hydroxide powder.

[0009] Preferably, the fiberglass tape layer includes at least two layers of fiberglass wire winding tapes, and the winding overlap rate is 40-50%.

[0010] Preferably, the armor layer includes a first layer of longitudinally sparsely wound steel wires and a second layer of longitudinally sparsely wound steel wires. Among them, on the outer layer of the winding tape, the first layer of longitudinally sparsely wound steel wires is first sparsely wound, and then the second layer of longitudinally sparsely wound steel wires is reversely wound. The steel wires in the first layer of longitudinally sparsely wound steel wires and the steel wires in the second layer of longitudinally sparsely wound steel wires form an angle of 30°-35°.

[0011] Preferably, the cable core includes a plurality of conductors tangent to each other in pairs. A filling layer is provided between the plurality of conductors tangent to each other in pairs, and the cable core with a circular cross-section is formed by winding and fixing with a wrapping tape.

[0012] Preferably, the conductor includes:

[0013] A conductor core formed by a plurality of stranded oxygen-free copper single wires;

[0014] An insulating layer extruded on the outer wall of the conductor core;

[0015] A polyvinyl chloride flame retardant layer extruded on the outer wall of the insulating layer.

[0016] Preferably, the insulating layer includes a double-extruded insulating layer of a conductor shielding layer and a conductor insulating layer.

[0017] Preferably, the flame retardant layer includes a flame retardant rope and a semiconductive resistance water powder.

[0018] Preferably, after being loosely wound to form an armor layer, the cable core is passed through a box filled with inorganic water-setting powder, and when passing through the box, it is wrapped with a water-soluble film to fix the inorganic water-setting powder. Then, the cable core is passed through a box filled with aluminum hydroxide powder, and when passing through the box, it is wrapped with a glass fiber ribbon to shape the aluminum hydroxide powder, thus forming a flame retardant layer.

[0019] Compared with the prior art, the significant advantages of the flame retardant B1-level environmentally friendly power cable of the present invention are as follows:

[0020] The flame retardant B1-level environmentally friendly power cable of the present invention is provided with a flame retardant layer on the outer layer of the armor layer. The flame retardant layer combines a water-setting powder and a flame retardant powder that decomposes water when heated. After the cable is heated, the water decomposed from the flame retardant powder combines with the water-setting powder to form a hard shell, preventing the flame from penetrating further inward, protecting the internal cable structure, and avoiding electrical circuit failures. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings are not intended to be drawn to scale. In the drawings, each identical or approximately identical component shown in each figure may be denoted by the same reference numeral. For clarity, not every component is labeled in each figure. Now, embodiments of various aspects of the present invention will be described by way of examples and with reference to the drawings.

[0022] Figure 1 is a schematic cross-sectional structure diagram of the flame retardant B1-level environmentally friendly power cable shown in the present invention.

[0023] Figure 2 is a schematic structure diagram of the armor layer and the flame retardant layer shown in the present invention.

[0024] Figure 3 is a schematic structure diagram of the steel wire braiding shown in the present invention. Detailed implementation manners

[0025] To better understand the technical content of the present invention, specific embodiments are hereby given and described in conjunction with the accompanying drawings as follows.

[0026] In current flame-retardant cables, usually one to three layers of fiberglass flame-retardant layers are made in the inner layer of the cable. However, under high-temperature heating, the fiberglass will melt into a fluid and drip, losing the protective effect on the inner-layer cable structure, and the inner-layer structure continues to be heated until the cable core is broken down.

[0027] In view of the defects of the prior art, in combination with Figure 1 As shown in the figure, a first aspect of the present invention provides a flame-retardant B1-level environmental protection power cable, which includes a cable core, an armor layer 4, a flame-retardant layer 5, and an outer sheath 6 distributed from the inside to the outside along the conductor cross-section.

[0028] Among them, the outer sheath 6 is made of irradiated cross-linked low-smoke and halogen-free flame-retardant polyolefin insulating material.

[0029] Optionally, the cable core includes a plurality of conductors 1 tangent to each other in pairs (illustrated by taking three as an example for explanation). A filling layer 2 is provided between the plurality of conductors 1 tangent to each other in pairs, and is wound and fixed into a cable core with a circular cross-section by a wrapping tape 3.

[0030] Among them, the conductor 1 includes a conductor core 11 formed by a plurality of stranded oxygen-free copper single wires, and can be formed by a 1 + 6 + 12 right-regular stranding method.

[0031] The insulating layer is extruded on the outer wall of the conductor core 11; the polyvinyl chloride flame-retardant layer 14 is extruded on the outer wall of the insulating layer. The polyvinyl chloride flame-retardant layer 14 is made of an environment-friendly polyvinyl chloride, has an obvious smoke suppression effect, and simultaneously plays a role in environmental protection.

[0032] Preferably, the insulating layer includes a double-layer co-extruded insulating layer of a conductor shielding layer 12 and a conductor insulating layer 13.

[0033] The conductor shielding layer 12 is equipotential with the shielded conductor, has good contact with the insulating layer 13, and prevents partial discharge between the conductor 11 and the insulating layer 13. The conductor shielding layer 12 is preferably ethylene-vinyl acetate copolymer. The material of the conductor insulating layer 13 is preferably irradiated cross-linked low-smoke and halogen-free flame-retardant polyolefin insulating material.

[0034] Furthermore, in order to improve the flame retardancy of the cable core and the roundness of the entire cable, the filling layer 2 includes a flame-retardant rope and a semiconductive resistance water powder. A mica tape is wound around the outer wall of the filling layer 2 to form a wrapping tape layer.

[0035] The armor layer 4 is arranged on the outer layer of the wrapping tape 3 to increase the strength of the cable. A flame-retardant layer 5 is arranged on the outer layer of the armor layer 4 to play a role in flame retardancy and preventing thermal breakdown.

[0036] Among them, the flame retardant layer 5 includes a hydro-setting powder layer 51, a water-soluble film 52, a flame retardant powder layer 53, and a fiberglass tape layer 54 distributed from the inside to the outside. The hydro-setting powder layer 51 includes a first part in a microporous structure and a second part outside the cross-section of the armor layer 4. The flame retardant powder layer 53 is configured to release water when heated, causing the hydro-setting powder layer 51 to form a hard shell.

[0037] The present invention aims to utilize the water released by the flame retardant powder layer 53 when heated to combine with the hydro-setting powder layer 51 to form a hard shell for hardening flame retardancy, thereby protecting the inner cable structure and preventing the inner layer from being burned through.

[0038] Preferably, the hydro-setting powder layer 51 includes inorganic hydro-setting powder, and the inorganic hydro-setting powder is coated and solidified by the water-soluble film 52. Thus, when the cable is in a normal laying environment, the flame retardant layer does not limit the bending angle of the cable, and the cable still has good flexibility. At the same time, the hydro-setting powder layer 51 is also restricted within a predetermined space and does not flow disorderly.

[0039] Preferably, the inorganic hydro-setting powder includes sulfoaluminate cement powder. The sulfoaluminate cement powder can quickly solidify when encountering water to form a hard and non-combustible outer shell to protect the inner cable structure.

[0040] In an alternative embodiment, the flame retardant powder layer 53 includes water-saturated resin powder or aluminum hydroxide powder. Thus, when the powder is heated, it will release water, and after the water passes through the water-soluble film 52, it combines with the powder in the hydro-setting powder layer 51 to form a hard outer shell, playing a protective role.

[0041] Furthermore, in an alternative embodiment, the armor layer 4 includes a steel wire mesh structure, and a microporous structure is formed between the steel wire mesh structures. Thus, the bonding ability between the formed outer shell and the inner layer can be increased to prevent the formed outer shell from falling off.

[0042] In a preferred embodiment, the armor layer 4 includes a first layer of longitudinally wound steel wires 41 and a second layer of longitudinally wound steel wires 42. In an alternative example, the steel wires in the first layer of longitudinally wound steel wires 41 and the steel wires in the second layer of longitudinally wound steel wires 42 form an angle of 30° - 35°. Thus, by winding two layers of steel wires to form the armor layer, a plurality of microporous structures can be formed for accommodating and storing powder.

[0043] Preferably, in order to enable the flame retardant powder layer 53 to have sufficient time to release water and combine with the hydro-setting powder during a fire, the fiberglass tape layer 54 includes at least two layers of fiberglass filament wrapping tapes, and the wrapping overlap rate is 40 - 50%. Through the flame retardant effect of the fiberglass filament wrapping tapes, the time for the flame to penetrate the fiberglass tape layer 54 can be delayed, creating time for the flame retardant powder layer 53 to release water when heated and combine with the hydro-setting powder.

[0044] In an alternative embodiment, a first layer of longitudinally loosely wound steel wires 41 is loosely wound around the outer layer of the wrapping tape 3, and then a second layer of longitudinally loosely wound steel wires 42 is wound in the reverse direction. The wires in the first layer of longitudinally loosely wound steel wires 41 and the wires in the second layer of longitudinally loosely wound steel wires 42 form an angle of 30°-35°. After the armor layer is wound, the cable is passed through a box filled with sulfoaluminate cement powder, and when passing through the box, it is wrapped with a water-soluble film 52 to solidify the powder. Then the cable is passed through a box filled with aluminum hydroxide powder, and when passing through the box, it is wrapped with a glass ribbon to shape the aluminum hydroxide powder, thus forming a flame retardant layer 5.

[0045] Combined with the above embodiments, the present invention provides a flame retardant layer on the outer layer of the armor layer. The flame retardant layer combines a water-setting powder and a flame retardant powder that decomposes water when heated. After the cable is heated, the water decomposed from the flame retardant powder combines with the water-setting powder to form a hard shell, preventing the flame from penetrating further inward, protecting the internal cable structure, and avoiding electrical circuit failures.

[0046] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Those with ordinary knowledge in the technical field to which the present invention pertains can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the scope defined in the claims.

Claims

1. A flame-retardant B1-level environmentally friendly power cable, characterized in that, It includes a cable core, an armor layer (4), a flame retardant layer (5), and an outer sheath (6) distributed from the inside to the outside along the cross-section of the conductor, where: The cable core includes a plurality of conductors (1) tangent to each other in pairs. A filling layer (2) is provided between the plurality of conductors (1) tangent to each other in pairs, and is wound and fixed into a cable core with a circular cross-section by a wrapping tape (3); the conductor (1) includes: a conductor core (11) formed by a plurality of stranded oxygen-free copper single wires, an insulating layer extruded on the outer wall of the conductor core, and a polyvinyl chloride flame retardant layer (14) extruded on the outer wall of the insulating layer; The armor layer (4) includes a steel wire mesh structure, and a microporous structure is formed between the steel wire mesh structures; The flame retardant layer (5) is located on the outer peripheral surface of the armor layer (4) and at least partially located in the microporous structure; The outer sheath (6) is made of irradiated cross-linked low-smoke and halogen-free flame retardant polyolefin insulating material and is extruded on the outer periphery of the flame retardant layer (5); Among them, the flame retardant layer (5) includes a hydrogel powder layer (51), a water-soluble film (52), a flame retardant powder layer (53), and a fiberglass tape layer (54) distributed from the inside to the outside; the hydrogel powder layer (51) includes a first part in the microporous structure and a second part outside the cross-section of the armor layer (4), and the flame retardant powder layer (53) is arranged to release water when heated, so that the hydrogel powder layer (51) forms a hard shell.

2. The flame-retardant B1-level environmentally friendly power cable according to claim 1, wherein The hydrogel powder layer (51) includes inorganic hydrogel powder, and the inorganic hydrogel powder is coated and fixed by the water-soluble film (52).

3. The flame-retardant B1-level environmentally friendly power cable according to claim 2, wherein, The inorganic hydrogel powder includes calcium sulfoaluminate cement powder.

4. The flame-retardant B1-class environmentally friendly power cable according to claim 1, characterized in that, The flame retardant powder layer (53) includes saturated resin powder or aluminum hydroxide powder.

5. The flame-retardant B1-class environmentally friendly power cable according to claim 1, wherein The fiberglass tape layer (54) includes at least two layers of fiberglass wire wrapping tapes, and the wrapping overlapping rate is 40 - 50%.

6. The flame-retardant B1-class environmentally friendly power cable according to any one of claims 1-5, characterized in that, The armor layer (4) includes a first layer of longitudinally sparsely wound steel wires (41) and a second layer of longitudinally sparsely wound steel wires (42); Among them, on the outer layer of the wrapping tape (3), the first layer of longitudinally sparsely wound steel wires (41) is first sparsely wound, and then the second layer of longitudinally sparsely wound steel wires (42) is wound in the reverse direction. The steel wires in the first layer of longitudinally sparsely wound steel wires (41) and the steel wires in the second layer of longitudinally sparsely wound steel wires (42) form an angle of 30° - 35°.

7. The flame-retardant B1-class environmentally friendly power cable according to claim 6, characterized in that, The armor layer (4) is formed by sparsely winding two layers of steel wires, forming a plurality of microporous structures for accommodating and storing powder.

8. The flame-retardant B1-level environment-friendly power cable according to claim 1, characterized in that, The insulating layer includes a double-layer co-extruded insulating layer formed by a conductor shielding layer (12) and a conductor insulating layer (13).

9. The flame-retardant B1-class environmentally friendly power cable according to claim 6, characterized in that, The flame retardant layer (5) includes a flame retardant rope and a semi-conductive resistance water powder.

10. The flame-retardant B1-class environment-friendly power cable according to claim 6, wherein, After sparsely winding to form the armor layer (4), the cable core is passed through a box filled with inorganic hydrogel powder, and when passing through the box, it is wrapped with a water-soluble film (52) to fix the inorganic hydrogel powder, and then the cable core is passed through a box filled with aluminum hydroxide powder, and when passing through the box, it is wrapped with a fiberglass ribbon to shape the aluminum hydroxide powder, thus forming the flame retardant layer (5).

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