Explosion-proof railway digital signal cable

Abstract

The invention discloses an explosion-proof railway digital signal cable, which comprises a flame-retardant cable core, and an inner explosion-proof layer, a flame-retardant shielding layer, an explosion-proof armor layer and an explosion-proof outer protective layer which are sequentially arranged outside the flame-retardant cable core from inside to outside, the flame-retardant cable core is formed by jointly twisting a plurality of twisted wire groups and a plurality of flame-retardant filling ropes, the exterior of the flame-retardant cable core is bound by a flame-retardant wrapping layer, each twisted wire group is formed by twisting a plurality of insulating single wires, and the flame-retardant cable core can be combined with a novel material through a multi-layer composite structure. The explosion-proof performance, the signal stability and the mechanical strength of the cable are remarkably improved, the safety and performance requirements of railway transportation on the signal cable can be met, and a powerful guarantee is provided for railway signal transmission in a high-risk environment.

Description

Technical Field

[0001] The present invention relates to the technical field of railway digital signal transmission, in particular to the technical field of railway digital signal cables. Background Art

[0002] In today's society, railway transportation is an important mode of transportation, and its safety and reliability are of vital importance. Railway digital signal cable is a communication cable specially used in railway signal systems. It undertakes the key tasks of transmitting control information, monitoring information and electrical energy, and is of great significance to ensuring the safety of trains and personnel.

[0003] The environment along railways is complex and diverse, and some areas may contain hazardous factors such as flammable and explosive gases or dust, such as railways near petrochemical zones and coal mine transportation lines. Once a railway digital signal cable fails and generates phenomena such as arcing and sparks, it is very easy to cause an explosion, resulting in serious casualties and property damage. With the continuous development of railway construction, people's performance requirements for railway digital signal cables are also increasing. Railway digital signal cables must not only have good electrical and mechanical properties, but also have better performance in fire resistance, explosion resistance, and anti-interference. However, traditional railway digital signal cables, such as the high-strength railway digital signal cable with insulation published with publication number CN103050181A, a high-compression railway digital signal cable with publication number CN111599524A, and a railway digital signal cable with comprehensive performance published with publication number CN103489519A, generally suffer from insufficient explosion-proof performance, weak anti-interference ability, low mechanical strength, and poor weather resistance in flammable and explosive environments, and cannot meet the safety requirements of high-risk scenarios.

[0004] In order to ensure the stability and reliability of railway signal transmission and guarantee the safe operation of railway systems in various complex environments, the research and development of explosion-proof railway digital signal cables has become an inevitable requirement for the development of the railway industry; in addition, relevant laws, regulations and safety standards have also put forward more stringent requirements on safety issues in railway transportation; therefore, the research and development of explosion-proof railway digital signal cables has important practical significance for promoting the safe development of the railway industry. Summary of the Invention

[0005] The purpose of the present invention is to solve the problems in the existing technology and propose an explosion-proof railway digital signal cable. Through a multi-layer composite structure and a combination of new materials, the explosion-proof performance, signal stability and mechanical strength of the cable can be significantly improved. It can meet the safety and performance requirements of railway transportation for signal cables and provide strong protection for railway signal transmission in high-risk environments.

[0006] To achieve the above-mentioned objectives, the present invention proposes an explosion-proof railway digital signal cable, comprising a flame-retardant cable core and an inner explosion-proof layer, a flame-retardant shielding layer, an explosion-proof armor layer and an explosion-proof outer sheath, which are sequentially arranged outside the flame-retardant cable core from the inside to the outside. The flame-retardant cable core is formed by twisting together a plurality of twisted wire groups and a plurality of flame-retardant filling ropes and is bounded on the outside by a flame-retardant wrapping layer. Each group of the twisted wire groups is formed by twisting together a plurality of insulated single wires.

[0007] Preferably, each of the insulated single wires is composed of a guide wire, a conductive oxygen-isolating barrier layer sprayed on the outside of the guide wire, and an insulating layer coated on the outside of the conductive oxygen-isolating barrier layer.

[0008] Preferably, the guide wire is made of a copper conductor with a diameter controlled at 0.8 to 1.2 mm, the conductive oxygen-isolating barrier layer is a graphene layer with a thickness controlled at 2 to 4 μm, and the insulating layer is formed by a low-density polyethylene inner layer, a polyolefin physical foaming layer, a high-density polyethylene outer layer and a silicone rubber layer extruded sequentially from the inside to the outside, and the thickness of the silicone rubber layer is controlled at 0.58 to 0.62 mm.

[0009] Preferably, the corresponding insulated single wires are twisted with different pitches between the twisted wire groups, and each group of the twisted wire groups is spirally wrapped with a high-temperature and corrosion-resistant cable tie, and the winding pitch is controlled at 28 to 33 mm.

[0010] Preferably, the flame retardant filling rope is a mica powder filled rope.

[0011] Preferably, the flame retardant wrapping layer is formed by overlapping a polyester tape and a ceramic silicone rubber tape in sequence, and the wrapping overlap rate is controlled at 20-25%, the thickness of the polyester tape is 0.02-0.08 mm, and the thickness of the ceramic silicone rubber tape is 0.1-0.3 mm.

[0012] Preferably, the inner explosion-proof layer is a flame-retardant rubber layer and the thickness is controlled at 0.7 to 0.9 mm.

[0013] Preferably, the flame retardant shielding layer includes a double-sided plastic-coated copper-plastic composite tape and a high flame retardant protective layer. The thickness of the double-sided plastic-coated copper-plastic composite tape is 0.2 to 0.4 mm. The double-sided plastic-coated copper-plastic composite tape is longitudinally wrapped around the inner explosion-proof layer and the longitudinal overlap rate is controlled at 6 to 8 mm. The high flame retardant protective layer is extruded and coated around the double-sided plastic-coated copper-plastic composite tape and the thickness is controlled at 1.2 to 1.8 mm.

[0014] Preferably, the explosion-proof armor layer is formed by gap wrapping of double-layer stainless steel strips with a thickness of not less than 0.3 mm, and the gaps between the wrappings are filled with explosion-proof putty.

[0015] Preferably, the explosion-proof outer protective layer includes a carbon nanotube layer and a modified silicone rubber layer, the carbon nanotube layer is formed by spraying carbon nanotubes outside the explosion-proof armor layer and the thickness is controlled at 0.10-0.14 mm, the modified silicone rubber layer is extruded and coated outside the carbon nanotube layer and the thickness is controlled at 1.8-2.2 mm, and the silicone rubber base material of the modified silicone rubber layer has a flame retardant added in a weight proportion of 12-18%.

[0016] The present invention discloses an explosion-proof, anti-interference, and highly weather-resistant railway digital signal cable. The cable can meet the safety application requirements of high-risk scenarios and ensure the safe operation of railway systems in various complex environments. It is very suitable for railway signal transmission systems in flammable and explosive environments such as tunnels, mining areas, and chemical industries. It has the following beneficial effects: 1) Excellent electrical performance and environmental adaptability: This invention utilizes high-purity oxygen-free copper conductors coated with a graphene barrier layer, ensuring excellent conductivity while effectively isolating oxygen and heat intrusion, guaranteeing stable signal transmission. The insulation layer utilizes a combination of skin-to-skin physical foaming and silicone rubber coating, which not only provides reliable electrical insulation but also gives the insulated single wire excellent high and low temperature resistance, weather resistance, flexibility, and flame retardancy and self-extinguishing properties. This allows the cable to maintain internal structural integrity and stable functionality over time despite the friction, collision, and complex climatic conditions experienced in harsh environments such as mines and construction. 2) Multiple, highly effective flame retardancy and high-temperature protection: The cable structure design incorporates a multi-layered flame retardant system. Specifically, the flame-retardant cable core is filled with mica powder-filled rope and coated with ceramic silicone rubber tape, which rapidly forms a ceramic shell that isolates the cable from oxygen when exposed to high temperatures. The flame-retardant shielding layer is equipped with a highly flame-retardant sheath. The explosion-proof outer sheath incorporates a high proportion of flame retardant within the silicone rubber matrix. This synergistic effect, from the inside out, significantly enhances the cable's overall flame retardancy, ensuring that flames can be effectively prevented from spreading and self-extinguished in fire or high-temperature environments, protecting the internal structure. 3) Strong explosion and impact resistance: The core innovation of this invention lies in the construction of a combined internal and external explosion-proof barrier. The inner explosion-proof layer (flame-retardant rubber) can suppress explosions caused by internal electric sparks or high temperatures. The explosion-proof armor layer uses a double layer of 316L stainless steel tape wrapped with gaps and filled with explosion-proof putty, providing excellent impact and corrosion resistance, effectively suppressing the splash of explosion fragments. The explosion-proof outer sheath is sprayed with carbon nanotubes and extruded with a modified silicone rubber layer to further enhance the external explosion and wear resistance. This design enables the cable to withstand severe impact and potential explosion risks in high-risk environments. 4) Excellent comprehensive environmental tolerance and long life: This design fully considers the challenges of extreme environments. Specifically, the high-temperature and corrosion-resistant cable ties use aramid fiber with an extremely wide temperature range and resistance to oil, acid and alkali. The explosion-proof armor layer uses highly corrosion-resistant 316L stainless steel, and the explosion-proof outer sheath has excellent weather resistance, UV resistance, chemical corrosion resistance, and abrasion resistance. The above material selection and structural design ensure that the cable has high performance retention and long service life in harsh railway and high-risk industrial environments such as oil pollution, electrolyte leakage, extreme temperatures, UV radiation, chemical corrosion and mechanical wear.

[0017] The features and advantages of the present invention will be described in detail through embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a cross-sectional view of the explosion-proof railway digital signal cable of the present invention; Figure 2 is a cross-sectional view of a twisted wire group of an explosion-proof railway digital signal cable according to the present invention; Figure 3 It is a cross-sectional view of an insulated single wire of an explosion-proof railway digital signal cable according to the present invention.

[0019] In the figure: 1-flame retardant cable core, 11-guide wire, 12-conductive oxygen barrier layer, 13-low-density polyethylene inner layer, 14-polyolefin physical foaming layer, 15-high-density polyethylene outer layer, 16-silicone rubber layer, 17-high-temperature and corrosion-resistant cable tie, 18-flame retardant filling rope, 2-polyester tape, 3-ceramic silicone rubber tape, 4-inner explosion-proof layer, 5-double-sided plastic-coated copper-plastic composite tape, 6-high flame retardant sheath, 7-explosion-proof armor layer, 8-carbon nanotube layer, 9-modified silicone rubber layer. DETAILED DESCRIPTION

[0020] See Figure 1 、 Figure 2 and Figure 3 The explosion-proof railway digital signal cable of the present invention includes a flame-retardant cable core 1 and an inner explosion-proof layer 4, a flame-retardant shielding layer, an explosion-proof armor layer 7 and an explosion-proof outer sheath, which are sequentially arranged outside the flame-retardant cable core 1 from the inside to the outside. The flame-retardant cable core 1 is formed by twisting seven groups of twisted wires and six flame-retardant filling ropes 18 together and is bounded by a flame-retardant sheath on the outside. Each group of the twisted wires is formed by twisting four insulated single wires (that is, each twisted wire group is a star-shaped four-wire group).

[0021] Each of the insulated single wires is composed of a guide wire 11 , a conductive oxygen-isolating barrier layer 12 sprayed on the outside of the guide wire 11 , and an insulating layer coated on the outside of the conductive oxygen-isolating barrier layer 12 .

[0022] The guide wire 11 is made of a copper conductor (high-purity oxygen-free copper) with a diameter controlled at 1 mm. The conductive oxygen-isolating barrier layer 12 is a graphene layer with a thickness controlled at 3 μm. The graphene layer can prevent the transmission of oxygen and heat while ensuring the electrical performance of the copper conductor. The insulating layer is formed by a low-density polyethylene inner layer 13, a polyolefin physical foaming layer 14, a high-density polyethylene outer layer 15, and a silicone rubber layer 16, which are extruded from the inside to the outside. The thickness of the silicone rubber layer 16 is controlled to be 0.6 mm. On the one hand, this insulating layer can provide sufficient electrical insulation performance for the insulated single wire. On the other hand, due to its excellent heat resistance, cold resistance, and weather resistance, it can prevent the internal structure of the cable from being damaged by frequent mechanical external forces such as friction and collision during use in high-risk environments such as mines and construction. In addition, this insulating layer also has good flame retardancy and self-extinguishing properties.

[0023] The corresponding insulated single wires of each group of twisted wires are twisted with different pitches, and each group of twisted wires is spirally tied with a high-temperature resistant and corrosion-resistant cable tie 17, and the winding pitch is controlled at 30 mm; wherein, the high-temperature resistant and corrosion-resistant cable tie 17 is an aramid fiber (PMIA) tape; in addition, different twisted wire groups can be spirally tied with aramid fiber tapes of different colors; aramid fiber has the characteristics of long-term temperature resistance over a wide range (can withstand temperature conditions of -196 to 204°C for a long time), is not easy to age in high-temperature areas near railway signal equipment, and is better than ordinary fibers in oil resistance, acid and alkali resistance, and has a performance retention rate of ≥95% in oil pollution and electrolyte leakage scenarios.

[0024] The flame retardant filling rope 18 is a mica powder filling rope.

[0025] The flame-retardant wrapping layer is formed by overlapping a polyester tape 2 and a ceramic silicone rubber tape 3 in sequence, and the wrapping overlap rate is controlled at 23%. The thickness of the polyester tape 2 is 0.05 mm, and the thickness of the ceramic silicone rubber tape 3 is 0.2 mm. Such a design can take into account the flexibility of the cable while enabling the cable to form a ceramic hard shell outside the cable core to isolate oxygen at high temperatures.

[0026] The inner explosion-proof layer 4 is a flame-retardant rubber layer with a thickness controlled at 0.8 mm, which can form a safety barrier to effectively prevent explosions caused by electric sparks or high temperatures that may be generated inside, and protect the flame-retardant cable core 1 from being damaged when subjected to external force impact.

[0027] The flame retardant shielding layer includes a double-sided plastic-coated copper-plastic composite tape 5 and a high flame retardant protective layer 6. The thickness of the double-sided plastic-coated copper-plastic composite tape 5 is 0.3 mm. The double-sided plastic-coated copper-plastic composite tape 5 is longitudinally wrapped around the inner explosion-proof layer 4, and the longitudinal overlap rate is controlled at 7 mm. The high flame retardant protective layer 6 is extruded and coated outside the double-sided plastic-coated copper-plastic composite tape 5, and the thickness is controlled at 1.5 mm. This double-layer structure can greatly improve the flame retardancy and anti-interference capabilities of the cable.

[0028] The explosion-proof armor layer 7 is formed by a double layer of stainless steel strips (316L stainless steel) with a thickness of not less than 0.3 mm, which are interspaced and filled with explosion-proof putty; this explosion-proof structure has good impact resistance and corrosion resistance, can suppress the splashing of explosion fragments, and can protect the internal structure of the cable from damage in harsh environments.

[0029] The explosion-proof outer sheath includes a carbon nanotube layer 8 and a modified silicone rubber layer 9. The carbon nanotube layer 8 is formed by spraying carbon nanotubes on the outside of the explosion-proof armor layer 7 and has a thickness of 0.12 mm. The modified silicone rubber layer 9 is extruded and coated on the outside of the carbon nanotube layer 8 and has a thickness of 2 mm. The silicone rubber matrix of the modified silicone rubber layer 9 has a flame retardant (aluminum hydroxide flame retardant, oxygen index ≥36) added at a weight ratio of 15%. This outer sheath, which is achieved through material composite and structural innovation, has good weather resistance, wear resistance and explosion-proof performance, can meet the multiple requirements of explosion-proof, weather resistance, flame retardancy and stable signal transmission in high-risk railway environments, and can resist the influence of factors such as ultraviolet rays, chemical corrosion and mechanical wear. In addition, under different climatic conditions and usage environments, this explosion-proof outer sheath can maintain stable performance for a long time, thereby extending the service life of the cable.

[0030] The above embodiments are intended to illustrate the present invention, not to limit the present invention. Any solution that is a simple transformation of the present invention falls within the protection scope of the present invention.

Claims

1. Explosion-proof railway digital signal cable, characterized by: The flame retardant cable core (1) comprises an inner explosion-proof layer (4), a flame retardant shielding layer, an explosion-proof armor layer (7) and an explosion-proof outer sheath which are sequentially arranged outside the flame retardant cable core (1) from the inside to the outside. The flame retardant cable core (1) is formed by twisting together a plurality of twisted wire groups and a plurality of flame retardant filling ropes (18) and is bounded on the outside by a flame retardant wrapping layer. Each group of the twisted wire groups is formed by twisting together a plurality of insulated single wires.

2. The explosion-proof railway digital signal cable according to claim 1, characterized in that: Each of the insulating single wires is composed of a guide wire (11), a conductive oxygen-isolating barrier layer (12) sprayed outside the guide wire (11), and an insulating layer coated outside the conductive oxygen-isolating barrier layer (12).

3. The explosion-proof railway digital signal cable according to claim 2, characterized in that: The guide wire (11) is made of a copper conductor with a diameter controlled at 0.8 to 1.2 mm, the conductive oxygen-isolating barrier layer (12) is a graphene layer with a thickness controlled at 2 to 4 μm, and the insulating layer is formed by a low-density polyethylene inner layer (13), a polyolefin physical foaming layer (14), a high-density polyethylene outer layer (15), and a silicone rubber layer (16) extruded sequentially from the inside to the outside, and the thickness of the silicone rubber layer (16) is controlled at 0.58 to 0.62 mm.

4. The explosion-proof railway digital signal cable according to claim 1, characterized in that: The corresponding insulated single wires are twisted with different pitches between the twisted wire groups, and each twisted wire group is spirally tied with a high-temperature and corrosion-resistant tie band (17) and the winding pitch is controlled at 28 to 33 mm.

5. The explosion-proof railway digital signal cable according to claim 1, characterized in that: The flame retardant filling rope (18) is a mica powder filling rope.

6. The explosion-proof railway digital signal cable according to claim 1, characterized in that: The flame retardant wrapping layer is formed by overlapping and wrapping a polyester tape (2) and a ceramic silicone rubber tape (3) in sequence, and the wrapping overlap rate is controlled at 20-25%. The thickness of the polyester tape (2) is 0.02-0.08 mm, and the thickness of the ceramic silicone rubber tape (3) is 0.1-0.3 mm.

7. The explosion-proof railway digital signal cable according to claim 1, characterized in that: The inner explosion-proof layer (4) is a flame-retardant rubber layer and its thickness is controlled to be 0.7-0.9 mm.

8. The explosion-proof railway digital signal cable according to claim 1, characterized in that: The flame retardant shielding layer comprises a double-sided plastic-coated copper-plastic composite tape (5) and a high flame retardant protective layer (6), wherein the thickness of the double-sided plastic-coated copper-plastic composite tape (5) is 0.2-0.4 mm, the double-sided plastic-coated copper-plastic composite tape (5) is longitudinally wrapped outside the inner explosion-proof layer (4) and the longitudinal wrapping overlap rate is controlled at 6-8 mm, and the high flame retardant protective layer (6) is extruded and coated outside the double-sided plastic-coated copper-plastic composite tape (5) and the thickness is controlled at 1.2-1.8 mm.

9. The explosion-proof railway digital signal cable according to claim 1, characterized in that: The explosion-proof armor layer (7) is formed by wrapping a double layer of stainless steel strips with a thickness of not less than 0.3 mm, and the wrapping gaps are filled with explosion-proof clay.

10. The explosion-proof railway digital signal cable according to claim 1, characterized in that: The explosion-proof outer protective layer comprises a carbon nanotube layer (8) and a modified silicone rubber layer (9), wherein the carbon nanotube layer (8) is formed by spraying carbon nanotubes outside the explosion-proof armor layer (7) and has a thickness controlled at 0.10 to 0.14 mm, and the modified silicone rubber layer (9) is extruded and coated outside the carbon nanotube layer (8) and has a thickness controlled at 1.8 to 2.2 mm, and a flame retardant having a weight ratio of 12 to 18% is added to the silicone rubber base material of the modified silicone rubber layer (9).

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