Flame-retardant high-shielding-performance railway long-distance communication cable

Abstract

The utility model belongs to the technical field of communication cables, and particularly relates to a flame-retardant high-shielding-performance railway long-distance communication cable, which comprises a plurality of groups of cable cores, and a heat insulation layer, an aluminum sheath layer, an inner protection layer, an armor layer and an outer protection layer which are sequentially arranged outside the plurality of groups of cable cores from inside to outside, the inner protection layer and the outer protection layer are made of low-smoke halogen-free flame-retardant polyolefin materials. The armor layer adopts a high-permeability steel belt, the magnetic permeability is not less than 530, the thickness is not less than 0.5 mm, and the wrapping clearance rate of the steel belt is controlled to be 40%-45%. The inner protective layer and the outer protective layer in the cable are made of low-smoke halogen-free polyolefin materials, and the armor layer is made of the high-permeability steel belt, so that the shielding performance and the flame-retardant performance of the railway communication cable are improved, and the railway communication cable is suitable for development of high-speed railways at present.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of communication cable, concretely relates to a kind of flame-retardant high shielding performance railway long-distance communication cable. BACKGROUND

[0002] With the development of high-speed railway, the requirement of railway long-distance communication cable to high-quality signal transmission is more and more strict.However, the cable in strong electric interference section requires its shielding performance ≤0.1, the shielding coefficient of general communication cable structure using aluminum sheath layer and ordinary galvanized steel belt is between 0.2~0.3, cannot satisfy the requirement of cable laid in strong electric interference section, and the precision of cable data transmission will be greatly affected.

[0003] At the same time, the laying environment of railway cable is complex, and the communication cable needs to have good flame-retardant performance.Once fire occurs, it is easy to cause the spread of fire and the generation of toxic smoke, which not only threatens the life safety of passengers, but also causes great difficulty to evacuation and rescue work.

[0004] Through retrieval, patent number CN202321553950.8 discloses an anti-interference steel wire armored long-distance symmetrical cable, which comprises six groups of four-core star quad wire groups arranged circumferentially at an interval of 60 degrees and jointly twisted to form a cable core by an isolation core frame, each group of four-core star quad wire group is composed of a four-core star quad wire core and two nylon anti-tension filling ropes, a hexagonal reinforcing core body is formed in the center of the isolation core frame, a central hole is formed in the hexagonal reinforcing core body, a four-core star quad wire core is sleeved in the central hole, and the cable core is sequentially covered with a PET resin wrapping layer, an extruded aluminum sleeve shielding layer, a nitrile polyvinyl chloride inner sheath layer, a steel wire inner armor layer, a steel wire outer armor layer and a nitrile polyvinyl chloride outer sheath layer.The main design is to design the mutual interference between the wires of the railway long-distance communication cable and the flexibility of the cable, seven four-core star quad wire cores are arranged by the isolation core frame, the effective electrical insulation interval is maintained, the mutual interference between the wire cores is inhibited, the near-end crosstalk influence between the loops is reduced, the four-core star quad wire core is filled with iron powder polypropylene composite resin, which is beneficial to the stress balance of the wire core, improves the mechanical strength and tensile strength, and the iron powder polypropylene composite resin filling core material and the polyester fiber plain weave cloth wrapping layer form a stable and reliable shielding effect, inhibit the mutual interference between the wire loops, and ensure the stability of signal transmission.But the structure and design of external high shielding performance and flame-retardant performance are not embodied, so the patent cannot guarantee the external high shielding performance and flame-retardant performance of the product. UTILITY MODEL CONTENTS

[0005] The utility model aims at providing a kind of flame-retardant high shielding performance railway long-distance communication cable, solve the problem that the shielding performance and flame-retardant performance of existing railway communication cable are poor.

[0006] The utility model is realized by the following technical solutions:

[0007] The utility model discloses a kind of flame-retardant high shielding performance railway long-distance communication cables, including multiple cable cores, and by inner to outer sequentially arranged in the outer of multiple cable cores heat insulation layer, aluminum sheath layer, inner protective layer, armored layer and outer protective layer;

[0008] Inner protective layer and outer protective layer are all used low-smoke halogen-free flame-retardant polyolefin material;

[0009] Armored layer uses high-permeability steel strip, magnetic permeability is not less than 530, thickness is not less than 0.5mm, steel strip is wrapped and is controlled at 40%~45% gap rate.

[0010] Further, the oxygen index of outer protective layer is ≥32%, and the thickness of outer protective layer is 1.8mm-2.0mm.

[0011] Further, the cable core is a skin bubble skin polyethylene insulation single wire.

[0012] Further, aluminum sheath layer uses aluminum metal strip, and the thickness is 1.8mm.

[0013] Further, heat insulation layer uses linear low-density polyethylene sheath material.

[0014] Further, the shielding coefficient of the flame-retardant high shielding performance railway long-distance communication cable is 0.06~0.08, and the flame-retardant performance reaches class B or above.

[0015] Further, the cable core specifically includes wire core conductor, and inner skin layer, foaming layer and outer skin layer wrapped outside wire core conductor.

[0016] Further, inner skin layer and outer skin layer are both extruded solid layer, and foaming layer is foam layer.

[0017] Further, the foaming degree of the foaming layer is 44%-46%.

[0018] Compared with prior art, the utility model has following beneficial technical effects:

[0019] The utility model discloses a kind of flame-retardant high shielding performance railway long-distance communication cables, including wire core cable, heat insulation layer, aluminum sheath layer, inner protective layer, armored layer and outer protective layer;The armored layer between inner protective layer and outer sheath is high-permeability steel strip, magnetic permeability is not less than 530, thickness is not less than 0.5mm, and cover rate control is not less than 40%~45%, increase the shielding performance of railway communication cable.The inner protective layer and outer sheath adopt low-smoke halogen-free flame-retardant polyolefin material, can prevent flame spread in combustion process, halogen-free acid gas is released, and the release amount of toxic and corrosive gas is extremely little, the smoke concentration produced is low, and the flame-retardant performance of railway communication cable is increased.

[0020] Further, the cable core adopts the skin-bubble-skin insulation wire core, the inner skin layer is a solid layer extruded on the conductor, the conductor and the insulation have good adhesion, the longitudinal moisture-proof performance of the insulation layer along the conductor surface is improved; the foam layer can reduce the dielectric constant, which is beneficial to long-distance signal transmission; the outer skin layer is a solid layer, which can ensure that the entire insulation layer has certain mechanical strength and good surface quality. The skin-bubble-skin insulation structure design cable has small diameter under the condition of equal capacitance, and can well meet the high-quality signal transmission requirement of the railway communication system. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 A structure schematic view of the flame-retardant high-shielding railway long-distance communication cable is provided in the utility model.

[0022] Figure 2 A skin-bubble-skin insulation structure schematic view of the cable core is provided.

[0023] The reference signs are explained as follows: 1, cable core; 2, heat insulation layer; 3, aluminum sheath layer; 4, inner protective layer; 5, armored layer; 6, outer protective layer.

[0024] 11, wire core conductor; 12, inner skin layer; 13, foaming layer; 14, outer skin layer. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical scheme and advantages of the utility model more clear and explicit, the following is further described in detail in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the utility model, and are not used to limit the utility model, that is, the described examples are only a part of the examples of the utility model, but not all examples.

[0026] The components described and shown in the drawings and examples of the utility model can be arranged and designed in various different configurations, therefore, the detailed description of the utility model examples provided in the following drawings is not intended to limit the scope of the claimed utility model, but only represents a selected embodiment of the utility model. Based on the drawings and examples of the utility model, all other examples obtained by those skilled in the art without creative labor are within the protection scope of the utility model.

[0027] It should be noted that the term "comprising", "including" or any other variant is intended to cover non-exclusive inclusion, so that the process, element, method, article or equipment including a series of elements includes not only those elements, but also other elements not explicitly listed, or further includes the elements inherent in the process, element, method, article or equipment.

[0028] The features and performance of the utility model are further described in detail in combination with the examples.

[0029] As Figure 1 shown, the flame-retardant high-shielding railway long-distance communication cable provided by the utility model, comprising cable core 1, heat insulation layer 2, aluminum sheath layer 3, inner sheath layer 4, armored layer 5 and outer sheath layer 6.

[0030] Specifically, the heat insulation layer 2, the aluminum sheath layer 3, the inner sheath layer 4 and the outer sheath layer 6 are sequentially arranged on the periphery of the cable core 1, and the armored layer 5 is arranged between the inner sheath layer 4 and the outer sheath layer 6.

[0031] The thickness of the aluminum sheath layer 3 is 1.8 mm, and the inner sheath layer 4 and the outer sheath layer 6 are both made of low-smoke halogen-free flame-retardant polyolefin material.

[0032] Specifically, the heat insulation layer 2 adopts linear low-density polyethylene sheath material.

[0033] Specifically, the aluminum sheath layer 3 adopts an aluminum metal belt.

[0034] The armored layer 5 is a high-permeability steel belt, the magnetic permeability of which is not less than 530, the thickness of which is 0.5 mm, and the wrapping gap rate of which is controlled at 40% to 45%, so that the shielding coefficient of the cable can reach 0.06 to 0.08, meeting the requirement that the shielding coefficient of the high-speed railway communication cable is less than or equal to 0.1.

[0035] The outer sheath layer 6 is an extruded black thermoplastic low-smoke halogen-free polyolefin sheath, the oxygen index of which is greater than or equal to 32%, the thickness of which is 1.8 mm to 2.0 mm, and the outer sheath layer 6 can prevent flame from spreading during the combustion process, and the halogen-free acid gas emission is small, and the toxic and corrosive gas emission is extremely small, and the smoke density generated is low.

[0036] More preferably, the cable core 1 is a skin-bubble-skin polyethylene insulated single wire. As Figure 2 shown, specifically includes wire core conductor 11, and inner skin layer 12, foaming layer 13 and outer skin layer 14 wrapped outside wire core conductor 11.

[0037] The conductor diameter is 1.4 mm, which ensures the voltage drop ΔU between the switch machine and the signal building at the transmission distance L1=2.5 km; according to the requirement that the four-wire group working capacitance is not greater than 28 nF / km, the size of the structure capacitance C of the insulated single wire is only related to the shape, size, mutual position of the conductor and the medium between the conductors. Therefore, the design and calculation of the insulated single wire can be seen in the following table:

[0038]

[0039] The skin bubble skin insulated wire core is formed by mixing high density polyethylene insulating material, low density polyethylene insulating material and nucleating agent in a certain ratio in a molten state, and injecting gas into the extruder barrel by a gas injection needle, so as to form a three-layer skin bubble skin insulated wire core. The inner skin layer 12 is a solid layer extruded on the conductor, which improves the adhesion between the conductor and the insulation and improves the longitudinal moisture-proof performance of the insulation layer along the surface of the conductor; the foaming layer 13 can reduce the dielectric constant, which is beneficial to the same signal between long-distance amplifiers; and the outer skin layer 14 is a solid layer, which can ensure that the entire insulation layer has certain mechanical strength and good surface quality.

[0040] The skin bubble skin insulated structure design cable has small diameter under the condition of equal capacitance, and can well meet the long-distance transmission requirement of the railway signal system.

[0041] The skin bubble skin insulation structure of the cable core 1 enables the signal cable to realize four-wire group working capacitance ≤ 26nF / km, and the transmission distance is increased to 5km.

[0042] The high shielding performance comprehensive sheath railway signal cable after the above improvement is tested to have a shielding coefficient of 0.06-0.08, meets the requirement of the shielding coefficient ≤ 0.1 of the communication cable of the high-speed railway, and the flame retardant performance meets the requirement of class B or above.

[0043] In summary, the utility model discloses a low smoke halogen-free polyolefin material is replaced to the black linear low density material of the inner sheath layer 4 and the outer sheath layer 6 in the existing cable, the armor layer 5 between the inner sheath layer 4 and the outer sheath layer 6 adopts high permeability steel strip, and the shielding performance and the flame retardant performance of the railway communication cable are increased, and simultaneously, the cable core 1 is skin bubble skin polyethylene insulation single wire, meets the long-distance transmission requirement of the railway signal system, and is suitable for the development of the high-speed railway.

[0044] Finally, it should be noted that: the above examples are only used to illustrate the technical scheme of the utility model and not to limit it, although the utility model has been described in detail with reference to the above examples, those skilled in the art should understand that: the specific implementation of the utility model can still be modified or replaced, and any modification or equivalent replacement without departing from the spirit and scope of the utility model should be covered in the protection scope of the claims of the utility model.

Claims

1. A flame-retardant, high-shielding railway long-distance communication cable, characterized in that, It includes multiple sets of cable cores (1), and heat insulation layer (2), aluminum sheath layer (3), inner sheath layer (4), armor layer (5) and outer sheath layer (6) arranged sequentially from the inside to the outside of the multiple sets of cable cores (1); Both the inner protective layer (4) and the outer protective layer (6) are made of low-smoke halogen-free flame-retardant polyolefin material; The armor layer (5) uses a high magnetic permeability steel strip with a magnetic permeability of not less than 530 and a thickness of not less than 0.5 mm. The steel strip wrapping gap ratio is controlled at 40% to 45%. The cable core (1) is a single wire with polyethylene foam insulation; The cable core (1) specifically includes a conductor (11), and an inner sheath (12), a foam layer (13), and an outer sheath (14) wrapped around the conductor (11). The inner skin layer (12) and the outer skin layer (14) are both extruded solid layers, and the foam layer (13) is a foam layer; The degree of foaming of the foamed layer (13) is 44%-46%; The oxygen index of the outer protective layer (6) is ≥32%.

2. The flame-retardant, high-shielding railway long-distance communication cable according to claim 1, characterized in that, The outer protective layer (6) has a thickness of 1.8mm-2.0mm.

3. The flame-retardant, high-shielding railway long-distance communication cable according to claim 1, characterized in that, The aluminum sheath layer (3) is made of aluminum metal strip with a thickness of 1.8 mm.

4. The flame-retardant, high-shielding railway long-distance communication cable according to claim 1, characterized in that, The insulation layer (2) is made of linear low-density polyethylene sheath material.

5. The flame-retardant, high-shielding railway long-distance communication cable according to claim 1, characterized in that, The flame-retardant, high-shield railway long-distance communication cable has a shielding coefficient of 0.06 to 0.08 and a flame-retardant performance of Class B or above.

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