A tin-plated copper-clad copper conductor thin-walled insulated fire-resistant flexible cable for rail transit

Abstract

This utility model relates to a thin-walled insulated fire-resistant flexible cable with tinned copper-clad copper conductor for rail transit, belonging to the field of cable manufacturing technology. The technical solution is as follows: a stranded tinned copper-clad copper conductor is wrapped with a calcined muscovite fireproof insulation layer; an irradiated cross-linked low-smoke halogen-free polyolefin insulation layer is extruded over the calcined muscovite fireproof insulation layer; the irradiated cross-linked low-smoke halogen-free polyolefin insulation layer is wrapped with the calcined muscovite insulation layer to form the conductor core; after single or multiple conductor cores are cabled, a second calcined muscovite insulation layer is wrapped around the outside; flame-retardant filler is filled between the second calcined muscovite insulation layer and the conductor core; a tinned copper wire braided shield is provided outside the second calcined muscovite insulation layer; and a cross-linked low-smoke halogen-free flame-retardant polyolefin sheath is extruded over the tinned copper wire braided shield. The positive effects of this utility model are: improved fire resistance and mechanical properties of the cable, ensuring the cable maintains its integrity under special flame conditions, and preventing personal injury and loss of public property.

Description

Technical Field

[0001] This utility model relates to a thin-walled insulated fire-resistant flexible cable with tin-plated copper-clad copper conductor for rail transit, belonging to the field of cable manufacturing technology. Background Technology

[0002] Rail transit refers to transportation vehicles that run on specific tracks. Rail transit can be divided into subways, trams, light rail, and high-speed rail, etc., used to carry passengers. In recent years, with the continuous development of the social economy, the national rail transit system has experienced rapid development, leading to a significant increase in demand for low-smoke halogen-free flame-retardant rail transit cables. Faced with constantly upgrading rail transit control equipment, higher requirements are placed on cables. Ordinary low-smoke halogen-free flame-retardant rail transit cables lack fire resistance and have low mechanical properties. For example, when a fire occurs in a densely populated rail transit carriage, existing rail transit cables cannot maintain the critical power control circuits for a certain period of time, failing to guarantee the power supply availability of critical equipment, resulting in casualties and damage to public property. Utility Model Content

[0003] The purpose of this utility model is to provide a tin-plated copper-clad copper conductor thin-walled insulated fire-resistant flexible cable for rail transit, which can maintain the critical power control circuit for a certain period of time, ensure the availability of power for critical equipment, buy time for the safe evacuation of passengers, and ensure the safety of the people and public property within a certain limit, thus solving the above-mentioned problems existing in the background technology.

[0004] The technical solution of this utility model is:

[0005] A thin-walled, fire-resistant, flexible cable with tinned copper-clad copper conductor for rail transit comprises stranded tinned copper-clad copper conductors, a calcined muscovite fireproof insulation layer, irradiated cross-linked low-smoke halogen-free polyolefin insulation, a first calcined muscovite insulation layer, a second calcined muscovite insulation layer, a tinned copper wire braided shield, a cross-linked low-smoke halogen-free flame-retardant polyolefin sheath, and flame-retardant filler. The stranded tinned copper-clad copper conductors are wrapped with the calcined muscovite fireproof insulation layer. The calcined muscovite fireproof insulation layer is then extruded with irradiated cross-linked low-smoke halogen-free polyolefin insulation. The irradiated cross-linked low-smoke halogen-free polyolefin insulation is wrapped with the first calcined muscovite insulation layer to form the conductor core. After one or more conductor cores are cabled, the second calcined muscovite insulation layer is wrapped around the outside. Flame-retardant filler is filled between the second calcined muscovite insulation layer and the conductor core. The second calcined muscovite insulation layer is surrounded by a tinned copper wire braided shield. The tinned copper wire braided shield is then extruded with a cross-linked low-smoke halogen-free flame-retardant polyolefin sheath.

[0006] Furthermore, the stranded tin-plated copper-clad copper conductor is formed by stranding multiple tin-plated soft copper-clad copper conductors. The tin-plated soft copper-clad copper conductor includes a central copper core, a copper cladding layer, and a tin plating layer. The central copper core is covered by a copper cladding layer, and a tin plating layer is attached to the outside of the copper cladding layer.

[0007] Furthermore, the number of wire cores and the number of flame-retardant fillers are both three, and the wire cores and flame-retardant fillers are arranged alternately.

[0008] The positive effects of this utility model are: improving the fire resistance and mechanical properties of cables, ensuring the integrity of the cable line under special flame conditions, and avoiding personal injury and loss of public property. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the tin-plated soft copper-clad copper conductor structure of this utility model;

[0010] Figure 2 This is a schematic diagram of the structure of this utility model;

[0011] In the diagram: 1. Stranded tin-plated copper-clad copper conductor; 11. Central copper core; 12. Copper cladding layer; 13. Tin plating layer; 2. Calcined muscovite fireproof insulation layer; 3. Irradiated cross-linked low-smoke halogen-free polyolefin insulation; 4. Calcined muscovite insulation layer one; 5. Calcined muscovite insulation layer two; 6. Tin-plated copper wire braided shield; 7. Cross-linked low-smoke halogen-free flame-retardant polyolefin sheath; 8. Flame-retardant filler. Detailed Implementation

[0012] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0013] A thin-walled, fire-resistant flexible cable with tinned copper-clad copper conductor for rail transit comprises: a stranded tinned copper-clad copper conductor 1; a calcined muscovite fireproof insulation layer 2; an irradiated cross-linked low-smoke halogen-free polyolefin insulation layer 3; a first calcined muscovite insulation layer 4; a second calcined muscovite insulation layer 5; a tinned copper wire braided shield 6; a cross-linked low-smoke halogen-free flame-retardant polyolefin sheath 7; and a flame-retardant filler 8. The stranded tinned copper-clad copper conductor 1 is wrapped with the calcined muscovite fireproof insulation layer 2. The core is formed by extruding an irradiated cross-linked low-smoke halogen-free polyolefin insulation 3 on the outside of the irradiated cross-linked low-smoke halogen-free polyolefin insulation 3 and then wrapping a calcined muscovite insulating layer 4 around it. After the single or multiple cores are cabled, a second calcined muscovite insulating layer 5 is wrapped around the outside. A flame-retardant filler 8 is filled between the second calcined muscovite insulating layer 5 and the core. A tinned copper wire braided shield 6 is provided outside the second calcined muscovite insulating layer 5. A cross-linked low-smoke halogen-free flame-retardant polyolefin sheath 7 is extruded outside the tinned copper wire braided shield 6.

[0014] The stranded tin-plated copper-clad copper conductor 1 is formed by stranding multiple tin-plated soft copper-clad copper conductors. The tin-plated soft copper-clad copper conductor includes a central copper core 11, a copper cladding layer 12, and a tin plating layer 13. The central copper core 11 is covered by the copper cladding layer 12, and the copper cladding layer 12 is covered by the tin plating layer 13.

[0015] The number of wire cores and the number of flame-retardant fillers 8 are both three, and the wire cores and flame-retardant fillers 8 are arranged at intervals.

[0016] See appendix Figure 1 In this embodiment, the conductor is a Category 5 tin-plated soft copper-clad conductor conforming to the EN50306-2 standard. The tin-plated soft copper-clad conductor comprises a central copper core 11, a copper cladding layer 12, and a tin plating layer 13. The central copper core 11 is covered by the copper cladding layer 12, improving the cable's electrical performance and ensuring the cable resistance meets standard requirements. The copper cladding layer maintains the ductility of the copper conductor itself, facilitating crimping. The tin plating layer 13, surrounding the copper cladding layer 12, meets the 20-degree conductor resistance requirement of the cable and protects the copper wires. It also protects the internal integrity of the copper conductor from moisture and external environmental corrosion, maintaining stable conductor resistance, making the cable safer and increasing its service life.

[0017] Multiple tin-plated soft copper-clad copper conductors are bundled together to form the bundled tin-plated copper-clad copper conductor 1. The specific process is as follows: several tin-plated soft copper-clad copper conductors are concentrically bundled together in a left-hand direction, with a pitch of 8-14 times the bundle diameter. During stranding, a regular arrangement is maintained to ensure that the outer diameter of the bundled tin-plated copper-clad copper conductor 1 is stable and round, with a specification range of 0.5mm. 2 ~4mm 2 Compared to traditional soft conductors, this cable ensures that the conductor resistance meets requirements while allowing for a sufficiently small conductor strand pitch. The conductor is flexible and less prone to breakage, facilitating installation in confined spaces in rail transit vehicles, increasing cable lifespan, and reducing conductor material costs by approximately 10%. Furthermore, it provides continuous power supply in case of fire, ensuring basic lighting and safe braking of various safety door control systems.

[0018] See appendix Figure 2 This embodiment provides a 0.6 / 1KV tin-plated copper-clad copper conductor thin-walled insulated super fire-resistant flexible cable for rail transit, which consists of stranded tin-plated copper-clad copper conductor 1, calcined muscovite fireproof isolation layer 2, irradiated cross-linked low-smoke halogen-free polyolefin insulation 3, calcined muscovite isolation layer one 4, calcined muscovite isolation layer two 5, tin-plated copper wire braided shield 6, cross-linked low-smoke halogen-free flame-retardant polyolefin sheath 7, and flame-retardant filler 8.

[0019] The stranded tin-plated copper-clad copper conductor 1 is wrapped with 0.12mm thick calcined muscovite to form a calcined muscovite fireproof isolation layer 2. The calcined muscovite fireproof isolation layer 2 is wrapped in two layers with a 50% overlap, and the wrapping is flat. The overlap rate is controlled as required to ensure the stability of the wrapping coverage and to ensure that a stable and uniform protective shell is formed after external flame combustion to achieve the integrity of the circuit.

[0020] The calcined muscovite fireproof insulation layer 2 is externally extruded with an irradiated cross-linked low-smoke halogen-free polyolefin insulation layer 3. The thickness of the irradiated cross-linked low-smoke halogen-free polyolefin insulation layer 3 is controlled at 0.4 mm, and the extrusion concentricity is controlled at over 75%. The rated voltage of the cable is increased from the original standard 300 / 500V to 0.6 / 1KV, and the finished cable withstand voltage test is 3.5kV / 5 minutes. The cable withstand voltage exceeds the requirements of standard EN50306, improving the cable voltage rating and enabling normal operation under higher system voltages. While ensuring good electrical insulation performance, the insulation's oil resistance, flame retardancy, low-temperature resistance, and mechanical strength are enhanced. Through cross-linking, the cable's flexibility is maintained while improving and enhancing the insulation's aging resistance.

[0021] A high-grade cross-linked flame-retardant polyolefin is used. To ensure the flame-retardant performance of the cable, its oxygen index should not be less than 29. Since the insulation layer thickness is generally controlled at 0.4 mm, it needs to be irradiated to ensure its mechanical properties. The insulation strength after irradiation and cross-linking should not be less than 25 N / mm². 2 .

[0022] After insulation irradiation, a calcined muscovite insulating layer 4 is wrapped around it to form the wire core. The muscovite insulating layer 4 is wrapped with a single layer of calcined muscovite of 0.12mm and a 20% overlap rate.

[0023] Multiple conductors are twisted into a cable and then wrapped with a single layer of 0.12mm calcined muscovite with an overlap of 30-40%, forming a calcined muscovite insulating layer II. This layer serves both as a fire-resistant layer and protects the insulated conductors. This improves the cable's ability to maintain its electrical integrity under flame conditions, resulting in a fire resistance time exceeding 200 minutes, which is superior to the 120 minutes required by the EN50200 fire resistance standard.

[0024] Calcined muscovite can form an inorganic protective shell when exposed to high-temperature flames. Even if the outer or surrounding combustibles ignite, the circuit can still maintain its power supply, and the control switches of the relevant circuits can be controlled and normal safety lighting can be provided.

[0025] The calcined muscovite insulating layer 25 and the outer braided tin-plated copper wire braided shield 6 improve the cable's flexibility, reduce conductor breakage, and ensure a smooth braided conductor surface that does not loosen after sheathing, facilitating terminal crimping and cable termination, and making cable installation and use easier.

[0026] The tinned copper wire braided shield 6 has a braided single wire diameter related to the core diameter. The braided single wire is 0.1-0.15mm, the braiding machine is a 16-spindle braiding machine, the braiding density is 80%, and the braiding angle is 15°-35°. The tinned copper wire braided shield 6 reduces electromagnetic interference from control signals and high-voltage electricity, stabilizes the control circuit, and maintains the cable's flexibility, making it easy to bend.

[0027] The tin-plated copper wire braided shield 6 is externally extruded with a cross-linked low-smoke halogen-free flame-retardant polyolefin sheath 7, which improves the cable's flexibility and low-temperature resistance. It not only has better mechanical properties such as wear resistance and low-temperature resistance, but also has comprehensive protective properties such as oil resistance and corrosion resistance, thus improving the cable's safety protection and service life.

[0028] The outermost sheath is made of cross-linked low-smoke halogen-free flame-retardant material. After cross-linking, its strength is improved, its aging resistance is enhanced, and it also has excellent oil and corrosion resistance.

[0029] In this embodiment, the cross-linked low-smoke halogen-free flame-retardant polyolefin sheath 7 is made of Linhai Yadong low-smoke halogen-free flame-retardant oil-resistant sheath material, which has excellent mechanical properties and comprehensive protective performance.

[0030] Flame-retardant filler 8 is filled into the cable core to enhance the flame-retardant effect of the cable and slow down the spread of flames.

[0031] This utility model of cable is mostly used in locomotive control cabinets and cab wiring, encountering various harsh operating environments. The sheath material possesses excellent oil resistance, acid and alkali resistance, UV protection, abrasion resistance, cold resistance, high strength, toughness, and aging resistance. The high-performance three-layer calcined muscovite fireproof layer design greatly enhances the cable's fire resistance and flame retardant properties. Testing shows the cable can withstand flame temperatures up to approximately 1000 degrees Celsius, and after more than 200 minutes of fire resistance, it still maintains power transmission, effectively extending its fire resistance time. Excellent long-term aging performance guarantees a 30-year lifespan for the cable.

Claims

1. A stranded, tin-plated, copper-clad, copper-conductor, thin-walled, fire-resistant flexible cable for rail transit, characterized in that: The structure comprises a stranded tin-plated copper-clad copper conductor (1), a calcined muscovite fireproof insulation layer (2), an irradiated cross-linked low-smoke halogen-free polyolefin insulation layer (3), a calcined muscovite insulation layer one (4), a calcined muscovite insulation layer two (5), a tin-plated copper wire braided shield (6), a cross-linked low-smoke halogen-free flame-retardant polyolefin sheath (7), and a flame-retardant filler (8). The stranded tin-plated copper-clad copper conductor (1) is wrapped with a calcined muscovite fireproof insulation layer (2), and the calcined muscovite fireproof insulation layer (2) is extruded with an irradiated cross-linked low-smoke halogen-free flame-retardant polyolefin sheath (7). The core is formed by wrapping a calcined muscovite insulating layer (4) around the irradiated cross-linked low smoke halogen-free polyolefin insulation (3). After the core is cabled, a second calcined muscovite insulating layer (5) is wrapped around the outside. Flame retardant filler (8) is filled between the second calcined muscovite insulating layer (5) and the core. A tinned copper wire braided shield (6) is provided outside the second calcined muscovite insulating layer (5). A cross-linked low smoke halogen-free flame retardant polyolefin sheath (7) is extruded outside the tinned copper wire braided shield (6).

2. The stranded tin-plated copper-clad copper conductor thin-walled insulated fire-resistant flexible cable for rail transit according to claim 1, characterized in that: The stranded tin-plated copper-clad copper conductor (1) is formed by stranding multiple tin-plated soft copper-clad copper conductors. The tin-plated soft copper-clad copper conductor includes a central copper core (11), a copper cladding layer (12), and a tin plating layer (13). The central copper core (11) is covered with a copper cladding layer (12), and the copper cladding layer (12) is covered with a tin plating layer (13).

3. A stranded tin-plated copper-clad copper conductor thin-walled insulated fire-resistant flexible cable for rail transit according to claim 1 or 2, characterized in that: The number of wire cores and the number of flame-retardant fillers (8) are both three, and the wire cores and flame-retardant fillers (8) are arranged at intervals.

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