High-flame-retardant double-layer moisture-proof shielding axle counting cable for rail transit

Abstract

The utility model discloses a high-flame-retardant double-layer moisture-proof shielding type axle counting cable for rail transit, which comprises an axle counting line group consisting of a main line pair and a standby line pair, and a wrapping tape, an inner shielding layer, an inner oxygen-isolating lining layer, an outer shielding layer, an outer oxygen-isolating lining layer, an armored reinforcing layer and a sheath which are sequentially arranged outside the axle counting line group from inside to outside, and a plurality of drain wires are filled between the wrapping tape and the inner shielding layer, so that the cable has the characteristics of better flame-retardant, moisture-proof and shielding performance and easiness in maintenance, and fire risk and moisture influence can be greatly reduced, thereby ensuring stable transmission of rail transit signals (providing more reliable and stable signal transmission guarantee for a railway axle counting system), and improving the reliability of the railway axle counting system. And the safety and the reliability of railway operation are improved, and the device is particularly suitable for complex and severe railway operation environments.

Description

Technical Field

[0001] This utility model relates to the technical field of cables, and in particular to the technical field of axle-counting cables. Background Technology

[0002] The axle counter system is an important component of railway signaling systems, used to detect the number of axles when a train passes through a section of track to determine whether the section is occupied. Axle counter cables are cables primarily used in axle counter systems to transmit the signals required by the system and ensure its normal operation. Examples include the low-loss integrated axle counter signal cable for railway trains (publication number CN114758820A) and the manufacturing method of axle counter cables for urban rail transit (publication number CN104376905B).

[0003] However, the environmental conditions along railway lines are complex and varied, with numerous sources of electromagnetic interference (such as traction current from electric locomotives, radio frequency signals from communication equipment, and electromagnetic noise from nearby industrial equipment), as well as many humid areas (such as tunnels, underground passages, and areas near water sources). The aforementioned ordinary axle counting cables, due to their single-layer shielding design, have poor waterproofing, moisture-proofing, and shielding performance. This allows moisture to easily penetrate the cable through tiny gaps or damage in the cable sheath, affecting its normal operation. Cables located in the same laying trench can also interfere with each other, causing interference signals to be superimposed on the axle counting signal, ultimately leading to signal distortion, misjudgment, and affecting the accuracy of the axle counting system. These axle counting cables also often suffer from poor flexibility, temperature resistance, and fire resistance. In other words, when the bending radius is too small, the insulation layer and conductor inside the cable are easily compressed and deformed, leading to localized stress concentration (which may cause cable failure over time). Furthermore, in the event of a fire, the smoke and toxic gases produced by the burning cable pose a serious threat to personnel evacuation and equipment protection, thereby increasing the safety risks of railway transportation. Summary of the Invention

[0004] The purpose of this invention is to solve the problems in the existing technology and propose a high flame-retardant double-layer moisture-proof shielded axle counting cable for rail transit. It has good flame-retardant, moisture-proof and shielding performance as well as easy maintenance. It can significantly reduce the risk of fire and the impact of moisture, thereby ensuring the stability of rail transit signal transmission (providing more reliable and stable signal transmission guarantee for railway axle counting systems), improving the safety and reliability of railway operation, and is especially suitable for complex and harsh railway operating environments.

[0005] To achieve the above objectives, this utility model proposes a high flame-retardant double-layer moisture-proof shielded counting cable for rail transit, comprising a counting cable assembly composed of a main pair and a spare pair, and, from the inside out, a wrapping tape, an inner shielding layer, an inner oxygen-barrier liner, an outer shielding layer, an outer oxygen-barrier liner, an armor reinforcement layer, and a sheath arranged sequentially outside the counting cable assembly. Several drain lines are also filled between the wrapping tape and the inner shielding layer.

[0006] Preferably, the main wire pair and the spare wire pair are each formed by twisting together several spool-counting wires, and the spool-counting wires have guide wires and extruded blister insulation sleeves covering the guide wires.

[0007] Preferably, the guide wire is drawn from oxygen-free copper wire and its outer diameter is controlled between 1.398 and 1.405 mm. The foam insulation sleeve is composed of a polyolefin inner skin layer, a polyolefin foam layer, and a polyolefin outer skin layer arranged sequentially from the inside to the outside. The thickness of the polyolefin inner skin layer is controlled between 0.05 and 0.01 mm, the foaming degree of the polyolefin foam layer is controlled between 65 and 2%, and the thickness of the polyolefin outer skin layer is controlled between 0.3 and 0.1 mm.

[0008] Preferably, the strap is an embossed aluminum strip and is wrapped around the outside of the measuring axis assembly.

[0009] Preferably, the inner shielding layer is a single-sided plastic-coated aluminum (aluminum-plastic) composite strip with a thickness greater than 0.15 mm. The inner shielding layer is longitudinally wrapped between the wrapping strip and the inner oxygen-barrier lining layer, with the uncoated side facing the wrapping strip.

[0010] Preferably, the outer shielding layer is formed by seamless welding of an alloy aluminum plate with a thickness of 1.2 to 1.4 mm.

[0011] Preferably, the gap between the inner shielding layer and the outer shielding layer is controlled to be 2.8 to 3 mm.

[0012] Preferably, the inner oxygen-barrier liner, the outer oxygen-barrier liner, and the sheath are all formed by extrusion of polyolefin material with an oxygen index greater than 36%.

[0013] Preferably, the armor reinforcement layer is formed by wrapping two layers of galvanized steel strips with gaps, and the wrapping gap ratio is not greater than 35% of the bandwidth.

[0014] Preferably, the number of drainage lines is at least two, and the diameter of each line is not less than 0.5 mm.

[0015] The beneficial effects of this utility model are:

[0016] 1) Reliable cable core structure: It adopts a combination of main wire pair + spare wire pair, which can be used to quickly put the spare wire pair into use and continue to transmit signals when the main wire pair fails, thereby ensuring the continuity of communication transmission. It has the characteristics of high reliability and easy maintenance.

[0017] 2) Fast signal transmission speed and excellent flexibility: The main wire pair and spare wire pair are prepared by twisting the physical foamed single wire (i.e., the axle wire) separately. This not only greatly reduces the dielectric constant of the insulation material, effectively improves the signal transmission speed and quality, and reduces signal attenuation and distortion, but also gives the axle wire good flexibility (it is easier to bend during the laying process).

[0018] 2) Excellent shielding: By setting a double-layer shielding structure (single-sided aluminum-plastic composite tape longitudinal wrapping layer and seamless welded aluminum sheath layer), the cable can have excellent anti-electromagnetic interference capability and ensure the stability of signal transmission.

[0019] 4) High flame retardancy: By setting up double oxygen barriers and a high flame retardant outer sheath, in the event of a fire, the double oxygen barriers (one inner and one outer layer) can isolate oxygen (cut off the oxygen supply), prevent or delay the combustion process (inhibit the spread of flames), and buy more time for personnel evacuation and fire fighting and rescue. On the other hand, the high flame retardant outer sheath is halogen-free, environmentally friendly, produces little smoke, and has high insulation (it is not easily combustible in flames), which can reduce the speed of flame propagation to a certain extent and further enhance the overall fire resistance.

[0020] The features and advantages of this utility model will be described in detail through embodiments and accompanying drawings. Attached Figure Description

[0021] Figure 1 This is a cross-sectional view of the high flame-retardant double-layer moisture-proof shielded coaxial cable for rail transit of this utility model;

[0022] Figure 2 This is a cross-sectional view of the axle counting wire of the high flame-retardant double-layer moisture-proof shielded axle counting cable for rail transit, which is based on this utility model.

[0023] In the diagram: 1-Main pair, 2-Spare pair, 3-Wrapping tape, 4-Inner shielding layer, 5-Inner oxygen barrier liner, 6-Outer shielding layer, 7-Outer oxygen barrier liner, 8-Armor reinforcement layer, 9-Sheath, 10-Drain wire, 11-Guide wire, 12-Polyolefin inner skin layer, 13-Polyolefin foam layer, 14-Polyolefin outer skin layer. Detailed Implementation

[0024] See Figure 1 and Figure 2This utility model relates to a high flame-retardant double-layer moisture-proof shielded counting cable for rail transit, comprising a counting cable group consisting of a main line pair 1 and a spare line pair 2, and, from the inside out, a wrapping tape 3, an inner shielding layer 4, an inner oxygen-barrier liner 5, an outer shielding layer 6, an outer oxygen-barrier liner 7, an armored reinforcement layer 8, and a sheath 9 arranged sequentially outside the counting cable group. Several drain lines 10 are also filled between the wrapping tape 3 and the inner shielding layer 4.

[0025] The main wire pair 1 and the spare wire pair 2 are each formed by twisting together several spool-counting wires. Each spool-counting wire has a guide wire 11 and an extruded foam insulating sleeve covering the guide wire 11. The guide wire 11 is drawn from high-precision oxygen-free copper wire with an outer diameter controlled between 1.398 and 1.405 mm. The foam insulating sleeve is composed of a polyolefin inner sheath 12, a polyolefin foam layer 13, and a polyolefin outer sheath 14, arranged sequentially from the inside out. The thickness of the polyolefin inner sheath 12 is controlled at 0.05 ± 0.01 mm, the foaming degree of the polyolefin foam layer 13 is controlled at 65 ± 2%, and the thickness of the polyolefin outer sheath 14 is controlled at 0.3 ± 0.1 mm. The system employs a high-temperature resistant, high-insulation, and low-dielectric-content polyolefin material to create a foamed insulation sleeve, effectively ensuring normal data transmission from the innermost layer of the counting cable. Furthermore, the cable core (counting cable assembly) is constructed using a combination of main line pair 1 and spare line pair 2, offering advantages such as high reliability and ease of maintenance. Specifically, main line pair 1 handles signal transmission under normal conditions. When main line pair 1 malfunctions due to various reasons (such as mechanical damage, electrical faults, and environmental factors), spare line pair 2 can quickly take over and continue signal transmission, ensuring continuous communication and significantly improving the reliability and stability of the entire system.

[0026] The wrapping tape 3 is an embossed aluminum tape wrapped around the outside of the cable counter assembly. The embossed aluminum tape not only possesses good flexibility (ensuring the cable counter assembly is tightly bound) and shielding performance (blocking external electromagnetic interference and ensuring signal transmission stability), but also utilizes its uneven embossed texture to increase friction (because the surface of the embossed tape 3 is relatively rough, it increases the friction between it and adjacent layers, ultimately preventing the tape 3 from slipping or falling off during cable use), enhance flexibility (the embossed design allows the tape 3 to maintain mechanical strength while possessing better flexibility, facilitating cable bending and laying), and facilitate processing and installation (the embossed design allows the tape 3 to better adhere to adjacent structures).

[0027] The inner shielding layer 4 is a single-sided plastic-coated aluminum composite strip with a thickness greater than 0.15 mm. The inner shielding layer 4 is longitudinally wrapped between the wrapping strip 3 and the inner oxygen barrier liner 5, with the uncoated side facing the wrapping strip 3. The number of drain lines 10 is at least two, and the diameter of each line is not less than 0.5 mm. The inner shielding layer 4, together with the adjacent wrapping strip 3, inner oxygen barrier liner 5, and drain lines 10, can form a good moisture-proof and waterproof shielding barrier (composite moisture-proof shielding layer). When the cable is subjected to external electromagnetic interference, an induced current will be generated on the inner shielding layer 4. The drain lines 10, which are in close contact with the inner shielding layer 4, can quickly conduct these induced currents away, so that the interference signal is conducted to the ground through the drain lines 10, effectively avoiding the interference signal being reflected and superimposed inside the cable and affecting normal data transmission. In addition, the drain lines 10 also have the function of ensuring the electrical continuity of the inner shielding layer 4.

[0028] The outer shielding layer 6 is formed by seamless welding of an alloy aluminum plate with a thickness of 1.2 to 1.4 mm (the outer shielding layer 6 is the aluminum sheath moisture-proof shielding layer). The gap between the inner shielding layer 4 and the outer shielding layer 6 is controlled at 2.8 to 3 mm. The seamless welding can form a continuous and sealed aluminum sheath structure, thereby preventing external gases, liquids and impurities from entering the internal space of the cable on the one hand, and preventing leakage of internal materials of the cable on the other hand.

[0029] The inner oxygen barrier liner 5, outer oxygen barrier liner 7, and sheath 9 are all extruded from polyolefin material with an oxygen index greater than 36%. Specifically, the double oxygen barrier layers (inner oxygen barrier liner 5 and outer oxygen barrier liner 7) are extruded from high flame-retardant, low-smoke, halogen-free polyolefin sheath material with an oxygen index greater than 36%. This prevents oxygen from penetrating the cable when it is exposed to flames, thus protecting the cable axis assembly (avoiding damage due to combustion) and ensuring that the cable can maintain its basic functions for a certain period of time in the event of a fire, providing a guarantee for the normal operation of important equipment such as fire alarm systems and emergency lighting systems. In addition, the sheath 9 is made of a high- and low-temperature resistant, low-smoke, halogen-free polyolefin material with an oxygen index greater than 36% and good weather resistance (it needs to be able to be used stably at -40 to +80℃, and has the characteristics of being halogen-free, environmentally friendly, low-smoke, highly insulating, and having excellent UV resistance, with a minimum light transmittance >75%). This allows the cable to adapt to various harsh climatic conditions, such as high temperature, low temperature, UV radiation, humidity, and acid rain, effectively extending the service life of the cable.

[0030] The armor reinforcement layer 8 is formed by wrapping double-layer galvanized steel strips with gaps, and the wrapping gap ratio is no more than 35% of the bandwidth. During the laying and use of the cable, it may encounter bending, twisting and other situations. The armor reinforcement layer 8 can effectively enhance the overall rigidity and flexibility of the cable, so that it can resist these deformations to a certain extent and prevent the internal structure of the cable from being damaged due to excessive bending.

[0031] The above embodiments are illustrative of the present invention and are not intended to limit the present invention. Any simple modifications to the present invention are within the protection scope of the present invention.

Claims

1. A high flame-retardant double-layer moisture-proof shielding type axle-counting cable for rail transit, characterized in that: It comprises a metering axle line group composed of a main line pair (1) and a standby line pair (2), and a tape (3), an inner shielding layer (4), an inner oxygen barrier layer (5), an outer shielding layer (6), an outer oxygen barrier layer (7), an armored reinforcing layer (8) and a sheath (9) arranged outside the metering axle line group from inside to outside. ​ 2. The high flame retardant double layer moisture-proof shielding type axle counting cable for rail transit according to claim 1, characterized in that: The main line pair (1) and the standby line pair (2) are respectively formed by twisting a plurality of metering axle wires.

3. The high flame retardant double layer moisture-proof shielding type axle counting cable for rail transit according to claim 2, characterized in that: The wire (11) is drawn from oxygen-free copper wire and the outer diameter is controlled at 1.398-1.405 mm, the skin bubble skin insulation sleeve is composed of a polyolefin inner skin layer (12), a polyolefin foaming layer (13) and a polyolefin outer skin layer (14) arranged from inside to outside, the thickness of the polyolefin inner skin layer (12) is controlled at 0.05±0.01 mm, the foaming degree of the polyolefin foaming layer (13) is controlled at 65±2%, and the thickness of the polyolefin outer skin layer (14) is controlled at 0.3±0.1 mm.

4. The high flame retardant double layer moisture-proof shielding type axle counting cable for rail transit according to claim 1, characterized in that: The tape (3) is an embossed aluminum tape and is wrapped around the metering axle line group.

5. The high flame retardant double layer moisture-proof shielding type axle counting cable for rail transit according to claim 1, characterized in that: The inner shielding layer (4) is a single-sided plastic-coated aluminum composite tape with a thickness greater than 0.15 mm, and the inner shielding layer (4) is longitudinally wrapped between the tape (3) and the inner oxygen barrier layer (5) with the uncoated side facing the tape (3).

6. The high flame retardant double layer moisture-proof shielding type axle counting cable for rail transit according to claim 1, characterized in that: The outer shielding layer (6) is formed by seamless welding of an alloy aluminum plate with a thickness of 1.2-1.4 mm.

7. The high flame retardant double layer moisture-proof shielding type axle counting cable for rail transit according to claim 1, characterized in that: The gap between the inner shielding layer (4) and the outer shielding layer (6) is controlled at 2.8-3 mm.

8. The high flame retardant double layer moisture-proof shielding type axle counting cable for rail transit according to claim 1, characterized in that: The inner oxygen barrier layer (5), the outer oxygen barrier layer (7) and the sheath (9) are all formed by extrusion coating of polyolefin material with an oxygen index greater than 36%.

9. The high flame retardant double layer moisture-proof shielding type axle counting cable for rail transit according to claim 1, characterized in that: The armored reinforcing layer (8) is formed by gap winding of double-layer galvanized steel tape and the winding gap rate is not more than 35% of the tape width.

10. The high flame retardant double layer moisture-proof shielding type axle counting cable for rail transit according to claim 1, characterized in that: The number of drain wires (10) is at least two and the diameter of each wire is not less than 0.5 mm.

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