High-flame-retardant shielding digital communication cable

Abstract

The invention discloses a high-flame-retardant shielding digital communication cable, which enables the flame retardant property of the cable to be improved and meets the flame retardant grade requirement of a subway cable. The cable comprises four wire pairs, each wire pair is formed by twisting two single core wires with different colors, and the colors of the four wire pairs are different; a cross-shaped framework; an aluminum-mica tape; the outer sheath is a halogen-free low-smoke flame-retardant polyolefin sheath; a drain wire; and a rip cord; the cross-shaped framework is arranged in an inner cavity defined by the aluminum-mica tape, the cross-shaped framework divides the inner cavity into four arc-shaped cavities, each arc-shaped cavity is internally provided with a group of wire pairs, a cable core area formed by combining the cross-shaped framework and the four groups of wire pairs is internally and longitudinally provided with a drain wire, and the cross-shaped framework is arranged in the cable core area. The tearing rope is longitudinally arranged on the periphery of the aluminum-mica tape, the outer sheath is compounded on the periphery of the aluminum-mica tape, and aluminum foil of the inner layer of the aluminum-mica tape is arranged towards a cable core area.

Description

Technical Field

[0001] The invention relates to the technical field of cable structures, in particular to a highly flame-retardant shielded digital communication cable. Background Art

[0002] Cables for urban rail transit should have a higher combustion performance level. According to GB 31247-2014 "Combustion Performance Classification of Cables and Optical Cables", subway cables should meet the B1 standard. In addition, GB 55037-2022 "General Code for Building Fire Protection" and GB 51348-2019 "Electrical Design Standard for Civil Buildings" also clearly require that underground power cables and data communication cables in subway projects should use cables with combustion performance not lower than B1 or flame-retardant cables. Existing shielded data communication cables do not have the B1 function that meets GB 31247-2014 "Combustion Performance Classification of Cables and Optical Cables".

[0003] Therefore, it is necessary to carry out further technical innovation on the existing shielded digital communication cables. Summary of the invention

[0004] In view of the above problems, the present invention provides a highly flame-retardant shielded digital communication cable, which improves the flame-retardant performance of the cable and meets the flame-retardant grade requirements of subway cables.

[0005] A highly flame-retardant shielded digital communication cable, characterized in that it comprises:

[0006] Four wire pairs, each wire pair consists of two single-core wires of different colors twisted together, and the colors of the four wire pairs are different;

[0007] Cross skeleton;

[0008] Aluminum-mica tape;

[0009] An outer sheath, which is a halogen-free, low-smoke, flame-retardant polyolefin sheath;

[0010] Drain line;

[0011] and ripcord;

[0012] The cross frame is arranged in the inner cavity formed by the aluminum-mica tape, and the cross frame divides the inner cavity into four arc-shaped cavities, each of which is provided with a group of wire pairs, and a drainage wire is vertically placed in the cable core area formed by the combination of the cross frame and the four groups of wire pairs, and a tear rope is vertically placed on the periphery of the aluminum-mica tape, and the outer sheath is compounded on the periphery of the aluminum-mica tape, and the aluminum foil of the inner layer of the aluminum-mica tape is arranged toward the cable core area.

[0013] It is further characterized by:

[0014] The single core wires of each pair are formed by combining copper conductor and FEP insulation layer;

[0015] Four groups of wire pairs are twisted together at different pitches to form wire pairs;

[0016] One end of one of the cross frames is concave to form an embedding groove, the inner arc surface of the drain wire is embedded in the embedding groove, and the outer arc surface of the drain wire is in contact with the foil layer of the aluminum-mica layer;

[0017] The cross frame is made of halogen-free, low-smoke, flame-retardant polyolefin material with an oxygen index of 65;

[0018] The aluminum-mica tape comprises an inner aluminum foil and an outer mica tape, and the aluminum-mica tape is formed as a whole by bonding the mica tape with the aluminum foil, and the thickness of the aluminum foil is 0.012-0.02 mm; the mica tape is made by grinding mica ore into powder and adding a flame retardant binder, and the thickness of the mica tape is 0.12-0.2 mm;

[0019] The outer surface of the single-core wire is evenly covered with polyperfluoroethylene propylene (FEP) plastic, and made into eight colors: blue, white-blue, orange, white-orange, green, white-green, brown, and white-brown. Then two insulated single-core wires are twisted with different pitches into blue, white-blue pairs, orange, white-orange pairs, green, white-green pairs, and brown, white-brown pairs.

[0020] After adopting the structure of the present invention, wire pairs of different colors form four groups of wire pairs, and the four groups of wire pairs are respectively located in the corresponding independent arc cavities divided by the cross skeleton, and then coated with aluminum-mica tape. The aluminum-mica tape has a good metal shielding effect and can isolate the combustion heat outside, and has excellent flame retardant and fire resistant effects. At the same time, a halogen-free low-smoke flame retardant polyolefin sheath is used as an outer sheath. The shielded digital communication cable formed by the combination has high flame retardancy and meets the flame retardant grade requirements of subway cables. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a cross-sectional view of a specific embodiment of the present invention;

[0022] The names corresponding to the serial numbers in the figure are as follows:

[0023] Cross skeleton 1, embedding groove 101, aluminum-mica tape 2, outer sheath 3, drain wire 4, tear rope 5, single core wire 6, copper conductor 7, polytetrafluoroethylene propylene FEP insulation layer 8, arc cavity 9, wire pair 10. DETAILED DESCRIPTION

[0024] A highly flame retardant shielded digital communication cable, see Figure 1 : It includes four groups of wire pairs 10, a cross frame 1, an aluminum-mica tape 2, an outer sheath 3, a drain wire 4, and a tear cord 5;

[0025] Each wire pair 10 is formed by twisting two single core wires 6 of different colors, and the colors of the four wire pairs 10 are different. The single core wire 6 of each wire pair 10 is formed by combining a copper conductor 7 and a fluorinated ethylene propylene FEP insulation layer 8.

[0026] The outer sheath 3 is a halogen-free, low-smoke, flame-retardant polyolefin sheath;

[0027] A cross skeleton 1 is arranged in an inner cavity enclosed by an aluminum-mica tape 2, and the cross skeleton 1 divides the inner cavity into four arc-shaped cavities 9. A group of wire pairs 10 are arranged in each arc-shaped cavity 9. A drainage wire 4 is vertically placed in the cable core area formed by the combination of the cross skeleton 1 and the four groups of wire pairs 10. A tear rope 5 is vertically placed on the periphery of the aluminum-mica tape 2. The periphery of the aluminum-mica tape 2 is compounded with an outer sheath 3, and the inner aluminum foil layer of the aluminum-mica tape 2 is arranged toward the cable core area.

[0028] In a specific embodiment, the outer surface of the copper conductor 7 is uniformly coated with polyperfluoroethylene propylene (FEP) plastic and made into eight colors, namely, blue, white-blue, orange, white-orange, green, white-green, brown, and white-brown; and then two insulated single-core wires are twisted into blue, white-blue wire pairs, orange, white-orange wire pairs, green, white-green wire pairs, and brown, white-brown wire pairs at different pitches;

[0029] Four groups of wire pairs 10 are twisted at different pitches to form wire pairs, and the pitch is 10-20mm;

[0030] One end of one of the cross frames 1 is concave to form an embedding groove 101, the inner arc surface of the drain wire 4 is embedded in the embedding groove 101, and the outer arc surface of the drain wire 4 is attached to the aluminum foil of the aluminum-mica layer 2;

[0031] The cross frame 1 is made of halogen-free, low-smoke, flame-retardant polyolefin material with an oxygen index of 65;

[0032] The aluminum-mica tape 2 includes an inner aluminum foil and an outer mica tape. The aluminum-mica tape is formed by bonding the aluminum foil to the mica tape. The thickness of the aluminum foil is 0.012-0.02 mm. The mica tape is made by grinding mica ore into powder and adding a flame retardant adhesive. The thickness of the mica tape is 0.12-0.2 mm.

[0033] The halogen-free low-smoke flame-retardant polyolefin sheath used as the outer sheath 2 has an oxygen index of 65 and complies with the performance in the following table, has good flame-retardant effect, and excellent mechanical and physical properties.

[0034] project index density <![CDATA[1.57±0.02g / cm 3 ]]> Tensile Strength 12MPa Tensile strength after aging 10MPa Elongation at break 180％ Change rate of elongation at break after aging (maximum value) ±15％ Volume resistivity <![CDATA[≥1.0×10 10 Ohm]]> Environmental stress cracking resistance 96h Failure rate 0 / 10 Thermal deformation rate 90℃, 1Kg ≤20％ Limiting oxygen index 65±1％ Combustion gas pH value ≥4.3 Combustion gas conductivity ≤10μS / mm Hydrogen halide gas content ≤5mg / g hardness 50±2Shore D Low temperature embrittlement temperature -25(0 / 10)

[0035] Wire pairs of different colors form four groups of wire pairs, which are respectively located in the corresponding independent arc cavities divided by the cross frame, and then coated with aluminum-mica tape. The aluminum-mica tape has good metal shielding effect and can isolate the combustion heat outside. It has excellent flame retardant and fire resistant effects. At the same time, the halogen-free low-smoke flame retardant polyolefin sheath is used as the outer sheath. The shielded digital communication cable formed by the combination has high flame retardancy and meets the flame retardant grade requirements of subway cables.

[0036] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0037] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A highly flame-retardant shielded digital communication cable, characterized in that: It includes: Four wire pairs, each wire pair consists of two single-core wires of different colors twisted together, and the colors of the four wire pairs are different; Cross skeleton; Aluminum-mica tape; An outer sheath, which is a halogen-free, low-smoke, flame-retardant polyolefin sheath; Drain line; and ripcord; The cross frame is arranged in the inner cavity formed by the aluminum-mica tape, and the cross frame divides the inner cavity into four arc-shaped cavities, each of which is provided with a group of wire pairs, and a drainage wire is vertically placed in the cable core area formed by the combination of the cross frame and the four groups of wire pairs, and a tear rope is vertically placed on the periphery of the aluminum-mica tape, and the outer sheath is compounded on the periphery of the aluminum-mica tape, and the aluminum foil of the inner layer of the aluminum-mica tape is arranged toward the cable core area.

2. A highly flame-retardant shielded digital communication cable according to claim 1, characterized in that: The single core wires of each pair are formed by combining copper conductor and FEP insulation layer.

3. A highly flame-retardant shielded digital communication cable according to claim 1, characterized in that: Four groups of wire pairs are twisted together at different pitches to form a wire pair.

4. A highly flame-retardant shielded digital communication cable according to claim 1, characterized in that: One end of one of the cross frames is concave to form an embedding groove, the inner arc surface of the drain wire is embedded in the embedding groove, and the outer arc surface of the drain wire is in contact with the foil layer of the aluminum-mica layer.

5. A highly flame-retardant shielded digital communication cable according to claim 1, characterized in that: The cross frame is made of halogen-free, low-smoke, flame-retardant polyolefin material with an oxygen index of 65.

6. A highly flame-retardant shielded digital communication cable according to claim 1, characterized in that: The aluminum-mica tape comprises an inner aluminum foil and an outer mica tape. The aluminum-mica tape is formed as a whole by bonding the aluminum foil to the mica tape. The thickness of the aluminum foil is 0.012-0.02 mm. The mica tape is made by grinding mica ore into powder and adding a flame retardant adhesive. The thickness of the mica tape is 0.12-0.2 mm.

7. A highly flame-retardant shielded digital communication cable according to claim 2, characterized in that: The outer surface of the single-core wire is evenly covered with polyperfluoroethylene propylene (FEP) plastic, and made into eight colors: blue, white-blue, orange, white-orange, green, white-green, brown, and white-brown. Then two insulated single-core wires are twisted with different pitches into blue, white-blue pairs, orange, white-orange pairs, green, white-green pairs, and brown, white-brown pairs.

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