Special high-flame-retardant fireproof signal cable for rail transit

Abstract

The invention discloses a special high-flame-retardant and fire-resistant signal cable for rail transit, which ensures reliable shielding among different signals in the signal cable while improving the flame-retardant and fire-resistant performance of the signal cable. The cable comprises a cable core; and an outer cable sheath; the cable core comprises N lead groups, an outer shielding layer and a fourth flame-retardant fireproof layer, N is a natural number larger than or equal to 3, the N lead groups surround the periphery of the first center filling rope, the outer surfaces of the adjacent lead groups are at least provided with a contact area, the N lead groups form a center lead group structure after being surrounded, and the fourth flame-retardant fireproof layer is arranged between the outer shielding layer and the fourth flame-retardant fireproof layer. The outer surface of the central conductor group structure is coated with an outer shielding layer; the external cable sheath sequentially comprises a heat insulation layer, a second flame-retardant fireproof shielding layer, a fifth flame-retardant fireproof layer, a steel tape armoring layer and an outer sheath layer from inside to outside. And the thermal insulation layer is coated on the outer wall of the fourth flame-retardant fireproof layer.

Description

Technical Field

[0001] The present invention relates to the technical field of cable structures, and in particular to a highly flame-retardant and fire-resistant signal cable specially used for rail transit. Background Art

[0002] Subways, light rails, trams and maglev trains are usually one of the largest infrastructures in a city. They are also the main arteries of urban passenger transportation and the lifeline of the city. As a public transportation tool with a relatively large capacity, its safety is directly related to the life safety of the majority of passengers. The rail transit cables in the existing technology have poor resistance to disasters from inside and outside due to the design defects of the cable structure. In the small underground space, personnel and equipment are highly dense. Once a fire occurs, it takes a long time for the cable to extinguish itself after burning, which brings great difficulties to disaster relief work and causes greater damage and losses. Therefore, technical innovation of existing rail transit cables has become a general need.

[0003] In addition, after the existing signal cable conductor groups are manufactured, several conductor groups need to be twisted together to form a cable core, and then a circular shielding layer is coated on the outside of the cable core. During this manufacturing process, since several conductor groups need to be twisted together, the inner shielding layer pre-coated inside may deform, resulting in shielding failure, which in turn causes interference between different signal lines in the same conductor group, or interference between signals between different conductor groups. Therefore, how to solve the problem of signal interference between different signals in the signal cable is also a technical problem that needs to be solved urgently. Summary of the invention

[0004] In view of the above problems, the present invention provides a highly flame-retardant and fire-resistant signal cable specially used for rail transit, which improves the flame-retardant and fire-resistant performance of the signal cable while ensuring reliable shielding between different signals in the signal cable.

[0005] A highly flame-retardant and fire-resistant signal cable for rail transit, characterized in that it comprises: Cable core; and outer cable sheath; The cable core includes N groups of conductors, an outer shielding layer, and a fourth flame retardant and fire resistant layer, wherein N is a natural number greater than or equal to 3, the N groups of conductors are enclosed on the periphery of the first central filling rope, and the outer surfaces of adjacent conductor groups have at least one contact area, and the N groups of conductors are enclosed to form a central conductor group structure, the outer surface of the central conductor group structure is coated with an outer shielding layer, the outer shielding layer is wrapped around the outer surface of the central conductor group structure, and is fitted and coated corresponding to the outer convex arc edge area, and is coated with a straight edge corresponding to the transition area between the two guide groups, and the outer shielding layer is wrapped to form a shaped coating cavity corresponding to the central conductor group structure, a first buffer cavity is formed between the inner wall of the straight edge of the outer shielding layer and the outer wall of the corresponding conductor group, the first buffer cavity is filled with an inorganic filler, the outer periphery of the outer shielding layer is coated with a fourth flame retardant and fire resistant layer, the inner wall of the fourth flame retardant and fire resistant layer is a circular inner cavity, and the cavity between the inner wall of the fourth flame retardant and fire resistant layer and the outer shielding layer is filled with an inorganic filler; The outer cable sheath is composed of a heat insulation layer, a second flame retardant and fire resistant shielding layer, a fifth flame retardant and fire resistant layer, a steel belt armor layer, and an outer sheath layer from the inside to the outside; The heat insulation layer is coated on the outer wall of the fourth flame retardant and fire resistant layer.

[0006] It is further characterized by: The outer shielding layer is composed of at least two layers of aluminum foil tapes wrapped around the periphery of the central conductor group structure in batches to ensure the stable and reliable formation of the shaped covering cavity and the stable and reliable shielding; Each of the wire groups includes four insulated single wires of different colors. After the four insulated single wires of different colors are twisted, the outer periphery of the twisted insulated single wires is coated with an LD-PTFE tape, a first flame retardant and fire resistant shielding layer, and a third flame retardant and fire resistant layer in sequence; Each of the insulated single wires consists of a conductor, a first flame retardant and fire resistant layer, an insulating layer, and a second flame retardant and fire resistant layer. The conductor is sequentially coated with the first flame retardant and fire resistant layer, the insulating layer, and the second flame retardant and fire resistant layer. The color of the second flame retardant and fire resistant layer is set according to demand.

[0007] It is further characterized by: The inorganic filler is specifically a cylindrical inorganic filler guide pillar structure made of inorganic filler material, and the inorganic filler guide pillar structure is made of glass fiber rope and low-smoke halogen-free material to ensure reliable filling of the inner cavity and ensure that the entire cable has a certain deformation recovery function after assembly; The first flame retardant and fire resistant shielding layer is a composite sheath; The third flame retardant and fire resistant layer is composed of at least two layers of mica tape and at least three layers of flame retardant and fire resistant material; The first flame retardant and fire resistant layer is basalt fiber; The insulating layer is cross-linked polyethylene insulation; The second flame retardant and fire resistant layer and the fifth flame retardant and fire resistant layer are ceramic rubber fiberglass composite cloth; The fourth flame retardant and fire resistant layer is high silica glass fiber cloth; The heat insulation layer is made of expanded perlite, modified rice husk ash and nickel chloride; The second flame retardant and fire resistant shielding layer comprises an inner wall, a cavity and an outer wall; Ammonium phosphate fire extinguishing powder is arranged in the cavity of the second flame retardant and fire resistant shielding layer.

[0008] Compared with the prior art, the present invention has the following advantages: 1. The present invention adopts multiple fireproof designs to make the cable have the characteristics of low thermal conductivity, strong temperature and fire resistance, anti-friction, corrosion resistance and high strength; 2. The heat insulation layer, shielding layer, steel belt armor layer and outer sheath layer provided in the present invention make the cable have excellent shielding performance, high mechanical strength, and durability. The cable can withstand severe mechanical damage and has excellent impact resistance and vibration resistance. At the same time, it also ensures that the cable has excellent functions such as temperature resistance, moisture resistance, fire resistance, pressure resistance, and animal bite resistance, which fully meets the requirements of rail transit for cables; 3. Since a shaped covering cavity corresponding to the structure of the center conductor group is formed after the outer shielding layer is wrapped, a first buffer cavity is formed between the inner wall of the straight edge of the outer shielding layer and the outer wall of the corresponding conductor group, and the first buffer cavity is filled with inorganic fillers. By setting the outer shielding layer, the present invention eliminates the need for twisting when making the structure of the center conductor group. It is only necessary to arrange the conductor group at the periphery of the first center rope according to the set radial position and then cover it with the outer shielding layer. This prevents the first flame-retardant and fire-resistant shielding layer from being squeezed and deformed, reduces the actual length of the entire conductor group, reduces costs, and ensures reliable shielding between different signals in the signal cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a schematic cross-sectional structural diagram of a specific embodiment 1 of the present invention; Figure 2 It is a schematic cross-sectional view of a second specific embodiment of the present invention; The names corresponding to the serial numbers in the figure are as follows: The first center filling rope 1, the edge single wire is composed of a conductor 2, a first flame retardant and fire resistant layer 3, an insulating layer 4, a second flame retardant and fire resistant layer 5, a LD-PTEE wrapping tape 6, a first flame retardant and fire resistant shielding layer 7, a third flame retardant and fire resistant layer 8, a fourth flame retardant and fire resistant layer 9, a conductor group 10, an insulating layer 11, a second flame retardant and fire resistant shielding layer 12, a fifth flame retardant and fire resistant layer 13, a steel belt armor layer 14, and an outer sheath layer 15; An outer shielding layer 20, an arc edge 21, a straight edge 22, a first buffer cavity 30, an inorganic filler 40, and an insulating single wire 50; Cable core 100 and outer cable sheath 200 . DETAILED DESCRIPTION

[0010] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0011] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0012] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0013] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0014] A highly flame retardant and fire resistant signal cable for rail transit, see Figure 1 , Figure 2 : It includes a cable core 100 and an outer cable sheath 200; The cable core 100 includes N groups of conductors 10, an outer shielding layer 20, and a fourth flame retardant and fire resistant layer 9, wherein N is a natural number greater than or equal to 3, the N groups of conductors are enclosed on the outer periphery of the first central filling rope 1, and the outer surfaces of the adjacent conductor groups 10 have at least one contact area, and the N groups of conductors are enclosed to form a central conductor group structure, and the outer surface of the central conductor group structure is coated with an outer shielding layer 20, and the outer shielding layer 20 is wrapped around the outer surface of the central conductor group structure, and the outer convex arc edge area is adhered and coated to form an arc edge 21, corresponding to the two The transition area between the guide groups is covered with a straight edge 22, and the outer shielding layer 20 is wrapped to form a shaped covering cavity corresponding to the structure of the central wire group. A first buffer cavity 30 is formed between the inner wall of the straight edge 22 of the outer shielding layer 20 and the outer wall of the corresponding wire group 10. The first buffer cavity 30 is filled with an inorganic filler 40. The outer periphery of the outer shielding layer 20 is covered with a fourth flame retardant and fire resistant layer 9. The inner wall of the fourth flame retardant and fire resistant layer 9 is a circular inner cavity. The cavity between the inner wall of the fourth flame retardant and fire resistant layer 9 and the outer shielding layer is filled with an inorganic filler 40. The outer cable sheath is composed of a heat insulation layer 11, a second flame retardant and fire resistant shielding layer 12, a fifth flame retardant and fire resistant layer 13, a steel belt armor layer 14, and an outer sheath layer 15 from the inside to the outside; The heat insulation layer 11 is coated on the outer wall of the fourth flame retardant and fireproof layer 9 .

[0015] The outer shielding layer 20 is composed of at least two layers of aluminum foil tapes wrapped around the periphery of the central conductor group structure in batches to ensure the stable and reliable formation of the shaped covering cavity and to ensure stable and reliable shielding; Each conductor group 10 includes four insulated single wires 50 of different colors. After the four insulated single wires 50 of different colors are twisted, the outer periphery of the twisted insulated single wires 50 is sequentially coated with an LD-PTFE wrapping tape 6, a first flame retardant and fire resistant shielding layer 7 and a third flame retardant and fire resistant layer 8; Each insulated single wire is composed of a conductor 2, a first flame retardant and fire resistant layer 3, an insulating layer 4, and a second flame retardant and fire resistant layer 5. The conductor 2 is sequentially coated with the first flame retardant and fire resistant layer 3, the insulating layer 4, and the second flame retardant and fire resistant layer 5. The color of the second flame retardant and fire resistant layer 5 is set according to demand.

[0016] Specific embodiment 1, see Figure 1 The cable core 100 includes three groups of conductors 10, and the outer shielding layer 20 forms an outer contour of an equilateral triangle with rounded corners.

[0017] Specific embodiment 2, see Figure 2 The cable core 100 includes four groups of conductors 10, and the outer shielding layer 20 forms a square outer contour with rounded corners.

[0018] In the specific embodiments 1 and 2, the diameter of the conductor 2 ranges from 0.5 mm to 2.0 mm, and can be selected according to actual use requirements, so that the cable can meet different use requirements in various occasions and has a wide range of applications.

[0019] The inorganic filler 40 is specifically a cylindrical inorganic filler guide column structure made of inorganic filler material. The inorganic filler guide column structure is made of glass fiber rope and low-smoke halogen-free material to ensure reliable filling of the inner cavity and ensure that the entire cable has a certain deformation recovery function after assembly.

[0020] The first flame retardant and fireproof shielding layer 7 adopts a comprehensive sheath formed by longitudinally wrapping an aluminum-plastic composite tape with a thickness of not less than 0.18 mm and extruding a high flame retardant sheath in one step, and the sheath thickness is not less than 1.0 mm, so that the cable has excellent temperature resistance, shielding and moisture resistance.

[0021] The third flame retardant and refractory layer 8 is composed of at least two layers of mica tapes and at least three layers of flame retardant and refractory materials. The mica tape is the matrix, and a mixed slurry of flame retardant and refractory materials is covered on the mica tape. The refractory mica tape is formed after baking and curing. The refractory mica tape as a refractory layer can withstand a high temperature of at least 1100°C and has excellent thermal insulation properties, thereby blocking flames and heat transfer, and protecting the cable core from high temperature damage.

[0022] The first flame retardant refractory layer 3 is made of basalt ore as raw material, which is quickly drawn after being melted at a high temperature of 1450-1500°C. It has excellent chemical stability, high adaptability in harsh environments, and a wide range of operating temperatures.

[0023] The insulating layer 4 is made of cross-linked polyethylene insulating material. The cross-linked polyethylene insulating material is made by irradiating polyethylene with high-energy particle rays generated by an electron accelerator, so that the polyethylene molecules change from a linear molecular structure to a three-dimensional network structure, and from a thermoplastic material to a thermosetting material. It has excellent thermal deformation resistance, wear resistance, chemical resistance, stress cracking resistance and other properties, which prolongs the service life of the cable.

[0024] The second flame retardant and fire resistant layer 5 and the fifth flame retardant and fire resistant layer 13 are ceramic rubber glass fiber composite cloths, which have unique high temperature resistance, air permeability, excellent weather resistance, and excellent softness and toughness.

[0025] The fourth flame retardant and fire-resistant layer 9 is a high-silica glass fiber cloth, which can be used for a long time at a high temperature of 900°C, work for 10 minutes at 1450°C, and work for 15 seconds at 1600°C and remain in good condition. It has excellent properties such as high strength, low thermal conductivity, good chemical stability, high temperature resistance, and ablation resistance.

[0026] The thermal insulation layer 11 is made of expanded perlite, modified rice husk ash and nickel chloride in a weight ratio of 10:5:1. The synergistic effect of the multiple components can form a strong supporting structure during the fire protection process of the thermal insulation layer 11, preventing the expansion layer formed by the thermal insulation layer from melting or collapsing under flame erosion.

[0027] The second flame retardant and fire resistant shielding layer 12 includes an inner wall, a cavity and an outer wall. The material of the inner wall and the outer wall is copper, and ammonium phosphate fire extinguishing powder is arranged in the cavity, so that the cable has excellent shielding performance, vibration resistance, friction resistance, conductivity, bending performance, flame retardant and fireproof performance and corrosion resistance.

[0028] The outer sheath 15 is a ceramic silicone rubber sheath, which has excellent fireproof, flame retardant, low smoke and non-toxic properties. The extrusion molding process is simple. The residue after combustion is a hard ceramic shell. The hard shell does not melt or drip in a fire environment. It can withstand fire at a temperature of 950°C-1000°C for 90 minutes, thereby enhancing the flame retardant and fireproof performance of the cable and having high safety and reliability.

[0029] When making this cable: first, the wire drawing extrusion serial process is used to draw the copper rod into a copper conductor that meets the technical requirements, and the first flame retardant and fire resistant layer, the insulating layer, and the second flame retardant and fire resistant layer are formed at one time and coated on the outside of the copper conductor to complete the production of the insulated single wire; then, according to the requirements, the four insulated single wires of different colors produced are twisted by a high-speed star twisting machine, and the LD-PTEE tape, the first flame retardant and fire resistant shielding layer and the third flame retardant and fire resistant layer are coated on the outside in turn to complete the production of the conductor group.

[0030] Then, according to the order requirements, several produced wire groups are arranged in a ring around the periphery of the first central filling rope, and an outer shielding layer is formed by wrapping a double-layer aluminum foil tape, and then filled with inorganic fillers, and coated with a fourth flame retardant and fire-resistant layer to form a cable core, and then a thermal insulation layer is coated on the outside of the fourth flame retardant and fire-resistant layer, and then a high-temperature extrusion and filling process is used to extrude a copper tube that meets the technical requirements outside the thermal insulation layer, and ammonium phosphate fire extinguishing powder is filled into the copper tube cavity to complete the production of the second flame retardant and fire-resistant shielding layer. After the fifth flame retardant and fire-resistant layer, the steel belt armor layer and the outer sheath layer are sequentially coated on the outside of the second flame retardant and fire-resistant shielding layer, the high flame retardant and fire-resistant signal cable dedicated to rail transit of the present invention is manufactured.

[0031] To ensure that the electrical performance indicators of the cable are qualified, all wire groups in the cable core must maintain consistent tension during the production process.

[0032] Compared with the prior art, the present invention has the following advantages: 1. The present invention adopts multiple fireproof designs to make the cable have the characteristics of low thermal conductivity, strong temperature and fire resistance, anti-friction, corrosion resistance and high strength; 2. The heat insulation layer, shielding layer, steel belt armor layer and outer sheath layer provided in the present invention make the cable have excellent shielding performance, high mechanical strength, and durability. The cable can withstand severe mechanical damage and has excellent impact resistance and vibration resistance. At the same time, it also ensures that the cable has excellent functions such as temperature resistance, moisture resistance, fire resistance, pressure resistance, and animal bite resistance, which fully meets the requirements of rail transit for cables; 3. Since a shaped covering cavity corresponding to the structure of the center conductor group is formed after the outer shielding layer is wrapped, a first buffer cavity is formed between the inner wall of the straight edge of the outer shielding layer and the outer wall of the corresponding conductor group, and the first buffer cavity is filled with inorganic fillers. By setting the outer shielding layer, the present invention eliminates the need for twisting when making the structure of the center conductor group. It is only necessary to arrange the conductor group at the periphery of the first center rope according to the set radial position and then cover it with the outer shielding layer. This prevents the first flame-retardant and fire-resistant shielding layer from being squeezed and deformed, reduces the actual length of the entire conductor group, reduces costs, and ensures reliable shielding between different signals in the signal cable.

[0033] 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.

[0034] 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 and fire-resistant signal cable for rail transit, characterized in that: It includes: Cable core; and outer cable sheath; The cable core includes N groups of conductors, an outer shielding layer, and a fourth flame retardant and fire resistant layer, wherein N is a natural number greater than or equal to 3, the N groups of conductors are enclosed on the periphery of the first central filling rope, and the outer surfaces of adjacent conductor groups have at least one contact area, and the N groups of conductors are enclosed to form a central conductor group structure, the outer surface of the central conductor group structure is coated with an outer shielding layer, the outer shielding layer is wrapped around the outer surface of the central conductor group structure, and is fitted and coated corresponding to the outer convex arc edge area, and is coated with a straight edge corresponding to the transition area between the two guide groups, and the outer shielding layer is wrapped to form a shaped coating cavity corresponding to the central conductor group structure, a first buffer cavity is formed between the inner wall of the straight edge of the outer shielding layer and the outer wall of the corresponding conductor group, the first buffer cavity is filled with an inorganic filler, the outer periphery of the outer shielding layer is coated with a fourth flame retardant and fire resistant layer, the inner wall of the fourth flame retardant and fire resistant layer is a circular inner cavity, and the cavity between the inner wall of the fourth flame retardant and fire resistant layer and the outer shielding layer is filled with an inorganic filler; The outer cable sheath is composed of a heat insulation layer, a second flame retardant and fire resistant shielding layer, a fifth flame retardant and fire resistant layer, a steel belt armor layer, and an outer sheath layer from the inside to the outside; The heat insulation layer is coated on the outer wall of the fourth flame retardant and fire resistant layer.

2. According to claim 1, a highly flame-retardant and fire-resistant signal cable for rail transit, characterized in that: The outer shielding layer is composed of at least two layers of aluminum foil tapes wrapped around the outer periphery of the central conductor group structure in batches.

3. According to claim 1, a highly flame-retardant and fire-resistant signal cable for rail transit, characterized in that: Each of the wire groups includes four insulated single wires of different colors. After the four insulated single wires of different colors are twisted, the outer periphery of the twisted insulating single wires is coated with LD-PTFE tape, a first flame retardant and fire resistant shielding layer and a third flame retardant and fire resistant layer in sequence.

4. The highly flame-retardant and fire-resistant signal cable for rail transit according to claim 3, characterized in that: Each of the insulated single wires consists of a conductor, a first flame retardant and fire resistant layer, an insulating layer, and a second flame retardant and fire resistant layer. The conductor is sequentially coated with the first flame retardant and fire resistant layer, the insulating layer, and the second flame retardant and fire resistant layer. The color of the second flame retardant and fire resistant layer is set according to demand.

5. The highly flame-retardant and fire-resistant signal cable for rail transit according to claim 1, characterized in that: The inorganic filler is specifically a cylindrical inorganic filler guide column structure made of inorganic filler material, and the inorganic filler guide column structure is made of glass fiber rope and low-smoke halogen-free material.

6. A highly flame-retardant and fire-resistant signal cable for rail transit according to claim 4, characterized in that: The third flame retardant and fire resistant layer is composed of at least two layers of mica tapes and at least three layers of flame retardant and fire resistant materials.

7. The highly flame-retardant and fire-resistant signal cable for rail transit according to claim 4, characterized in that: The second flame retardant and fire resistant layer and the fifth flame retardant and fire resistant layer are ceramic rubber fiberglass composite cloth.

8. The highly flame-retardant and fire-resistant signal cable for rail transit according to claim 4, characterized in that: The heat insulation layer is prepared by compounding expanded perlite, modified rice husk ash and nickel chloride.

9. The highly flame-retardant and fire-resistant signal cable for rail transit according to claim 4, characterized in that: The second flame retardant and fire resistant shielding layer comprises an inner wall, a cavity and an outer wall.

10. A highly flame-retardant and fire-resistant signal cable for rail transit according to claim 9, characterized in that: Ammonium phosphate fire extinguishing powder is arranged in the cavity of the second flame retardant and fire resistant shielding layer.

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