A fireproof control cable and its manufacturing process

Abstract

The present invention discloses a fire-proof control cable, which comprises an inner conductor layer and an outer protective layer coated outside the inner conductor layer; the inner conductor layer is provided with a double-layer wire core, and the double-layer wire core is respectively an inner and an outer wire core, and the inner and outer wire cores are respectively formed by arranging a plurality of conductors. The ratio of the number of conductors in the inner wire core to the number of conductors in the outer wire core is 1:2-5. The outer protective layer is successively a flame-retardant tape layer, a copper wire braided layer, an oxygen-isolating inner protective layer, a steel tape armored layer, a fire-resistant and flame-retardant layer and an outer sheath. When in use, the cable of the present invention has excellent fire-proof and fire-resistant characteristics. The combustion performance of the cable reaches Class B1, and the additional classification meets the specified requirements of d0, t0, a1, so that under the rated working voltage, the flame temperature is not lower than 750 °C, and the fuse does not blow within 90 minutes of the fire supply time, which can ensure the smoothness of power and communication in case of fire and win precious time for personnel evacuation and fire fighting and rescue.

Description

Technical Field

[0001] The present invention mainly relates to the technical field of cables, and particularly relates to a fire-proof control cable and a manufacturing process thereof. Background Art

[0002] At present, with the rapid development of China's social economy, the requirements for industrial intelligence and automation are getting higher and higher. For traditional control cables, the requirements for flame retardancy in the national standard GB / T 9330-2008 generally adopt GB / T18380-2008 or IEC60332-3. Mainstream domestic cable enterprises have formed fixed process requirements and are mature products in terms of the flame retardancy performance of products. However, for the implemented standard of GB 31247-2014 "Classification of the burning performance of cables and optical cables", the research is not in-depth. Many people think that if the IEC60332-3 flame retardant Class B or Class A bundle burning test is qualified, B1 in GB 31247 should also meet the requirements, but in fact, the gap is very large.

[0003] The standard of GB 31247-2014 "Classification of the burning performance of cables and optical cables" mainly classifies the flame spread, heat release and smoke generation characteristics of cables under fire conditions. At the same time, for the needs of different use places and users, additional classifications are also carried out from aspects such as the smoke toxicity, corrosivity and combustion droppings / particles of cables under fire conditions.

[0004] The new standard comprehensively considers the safety performance of cables and has higher requirements. In view of the above situation, there is an urgent need in the market to develop a flame retardant B1 level fire-proof control cable to meet the requirements of the new standard. Summary of the Invention

[0005] In view of the above problems, the present invention provides a fire-proof control cable and a preparation method thereof. By setting a double-layer conductor and a multi-layer outer sheath, the cable has good fire-proof performance and the burning performance reaches Class B1.

[0006] The object of the present invention can be achieved by the following technical solutions: A fire-proof control cable, characterized in that the fire-proof control cable includes an inner layer of the conductor and an outer sheath covering the outside of the inner layer of the conductor; the inner layer of the conductor is provided with a double-layer wire core, and the double-layer wire core is respectively an inner and an outer layer wire core. The inner and outer layer wire cores are respectively formed by arranging a plurality of conductors. The ratio of the number of conductors in the inner layer wire core to the number of conductors in the outer layer wire core is 1:2-5. The outer sheath is successively a flame retardant tape layer, a copper wire braided layer, an oxygen isolation inner sheath layer, a steel tape armor layer, a fire-resistant flame retardant layer and an outer sheath.

[0007] Preferably, the conductor is a copper conductor, and an insulating layer and a fire-resistant layer are provided outside the conductor. The conductors of the inner layer wire core are arranged in a cable to the left in sequence, and the conductors of the outer layer wire core are arranged in a cable to the right in sequence. A glass fiber rope is filled between the inner and outer layer conductors.

[0008] Furthermore, the thickness of the flame-retardant tape layer is 0.4 - 0.6 mm, which is formed by winding non-alkali glass tape; the copper wire braided layer is made of copper wires with a single wire outer diameter of 0.2 mm, and the braiding density is greater than 80%.

[0009] A preparation method of a fire-proof control cable is characterized in that the preparation process is as follows: a. Prepare a double-layer wire core, the inner and outer layer wire cores are respectively arranged by a plurality of conductors, and the ratio of the number of conductors in the inner layer wire core to the number of conductors in the outer layer wire core is 1:2 - 5; b. Cable the double-layer wire core, the conductors of the inner layer wire core are arranged in a cable to the left in sequence, the conductors of the outer layer wire core are arranged in a cable to the right in sequence, and a glass fiber rope is filled between the inner and outer conductors; c. Extrude an outer sheath on the outside of the double-layer wire core, and the outer sheath is successively a flame-retardant tape layer, a copper wire braided layer, an oxygen-isolating inner sheath layer, a steel tape armor layer, a fire-resistant and flame-retardant layer, and an outer sheath.

[0010] Compared with the prior art, the technical solution of the present invention includes not only improvements in the overall technical solution, but also many improvements in details. Specifically, it has the following beneficial effects:

[0011] 1. In the improvement scheme of the present invention, the fire-proof control cable includes an inner conductor layer and an outer sheath covering the outside of the conductor; the inner conductor layer is provided with a double-layer wire core, and the double-layer wire core is respectively an inner and an outer layer wire core, so that the conductor has excellent fire-proof and fire-resistant characteristics, which can ensure the smooth flow of electricity and communication in case of fire, and strive for precious time for personnel to escape and fire fighting and rescue.

[0012] 2. In the technical solution of the present invention, the outer sheath is successively a flame-retardant tape layer, a copper wire braided layer, an oxygen-isolating inner sheath layer, a steel tape armor layer, a fire-resistant and flame-retardant layer, and an outer sheath, so that the combustion performance of the cable of the present invention reaches Class B1, and the additional classification meets the requirements of d0, t0, a1. When the cable is under the rated working voltage, the flame temperature is not lower than 750 °C, and the fuse does not break within 90 minutes of the fire supply time.

[0013] 3. The cable of the present invention has good heat insulation, with a thermal conductivity of 0.09 W / Mk. Especially, the inside after ablation is a uniform honeycomb shape, having better fire resistance and heat insulation.

[0014] 4. The present invention also has the effects of preventing ants, preventing rats from biting, waterproofing and resisting oil. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic structural diagram of the present invention.

[0016] The markings in the figure are as follows:

[0017] 1. Copper conductor 2. Insulation layer 3. Fire-proof layer;

[0018] 4. Flame retardant tape layer, 5 copper wire braided layer, 6 oxygen isolation inner sheath, 7 steel tape armor layer, 8 fire-resistant and flame-retardant layer, 9 outer sheath, 10 fiberglass rope;

[0019] 11 inner core, 12 outer core. Detailed implementation manner

[0020] The following will describe in detail the specific implementation manner of the present invention with reference to the accompanying drawings, so that those skilled in the art can more clearly understand how to practice the present invention. Although the present invention is described in conjunction with its preferred specific implementation embodiments, these embodiments are only illustrative and do not limit the scope of the present invention.

[0021] As Figure 1 shown, a fire control cable is different from the prior art in that the fire control cable includes an inner conductor layer and an outer sheath covering the outside of the inner conductor layer; the inner conductor layer is provided with a double-layer core, and the double-layer core is respectively the inner and outer cores 11 and 12. The inner and outer cores are respectively formed by arranging a plurality of conductors. The ratio of the number of conductors in the inner core to the number of conductors in the outer core is 1:2 - 5. The outer sheath is successively a flame retardant tape layer 4, a copper wire braided layer 5, an oxygen isolation inner sheath 6, a steel tape armor layer 7, a fire-resistant and flame-retardant layer 8, and an outer sheath 9.

[0022] The conductor uses a copper conductor 1, and the outside of the conductor is provided with an insulating layer 2 and a fireproof layer 3. The conductors of the inner core are arranged into a cable in sequence to the left, and the conductors of the outer core are arranged into a cable in sequence to the right. A fiberglass rope is filled between the inner and outer conductors. This enables the conductor to have excellent fireproof and fire-resistant properties, which can ensure the smooth flow of electricity and communication in case of a fire, and gain precious time for personnel to escape and for fire fighting and rescue.

[0023] In one embodiment, the inner conductor layer is provided with a double-layer core, and the double-layer core is respectively the inner and outer cores. The inner and outer cores are respectively formed by arranging a plurality of conductors. The inner core is composed of 4 conductors, and the outer core is composed of 10 conductors. Each conductor uses a round annealed soft copper conductor with a conductor diameter of 1.38 mm, and the outside of the conductor adopts a double-fireproof insulation layer structure. The inside is an insulating layer formed by overlapping and winding a mineral insulation fireproof tape, and the thickness of the tape is 0.14 mm. The outside is a fireproof layer extruded with a new type of fireproof material, ceramized polyolefin insulating material, and the thickness is 0.7 mm according to different specifications. In addition to having the characteristics of ordinary polyolefin insulating materials, the ceramized polyolefin fireproof insulating material also has excellent fireproof and fire-resistant properties. It can form a hard ceramic-like shell under the burning of a flame. This hard shell does not melt or drip in a fire environment (650°C - 3000°C), and has a very good heat insulation and fire isolation effect, which can ensure the smooth flow of electricity and communication in case of a fire, and gain precious time for personnel to escape and for fire fighting and rescue.

[0024] The extruded insulation layer uses yellow ceramic polyolefin insulation material, and each insulating core group is printed with numbers 1-14 for distinction. Furthermore, a spiral pattern is set on the surface of the ceramic polyolefin insulation material, a clockwise spiral pattern is set on the surface of the inner core, and a counterclockwise spiral thread is set on the surface of the outer core, so that the two remain relatively fixed after cabling, and the cabling effect is better. The spiral pattern here can be formed directly during the wrapping, or it can also be printed on the insulation material.

[0025] In another embodiment, the fireproof control cable includes an inner conductor layer and an outer sheath wrapped around the outside of the conductor; the inner conductor layer is provided with a double-layer core, the double-layer core is an inner core and an outer core respectively, the inner core and the outer core are respectively composed of a plurality of conductors arranged, the ratio of the number of conductors of the inner core to the number of conductors of the outer core is 1:2-5, and the outer sheath is sequentially a flame-retardant tape layer, a copper wire braided layer, an oxygen-isolating inner sheath, a steel belt armor layer, a fire-resistant flame-retardant layer and an outer sheath.

[0026] Furthermore, the cores are cabled in two layers, the inner layer 1-6 cores and the outer layer 7-18 cores. The inner layer is cabled in the left direction and the outer layer is cabled in the right direction. The cores are arranged in a clockwise direction from small to large. The gaps in the cores are filled with glass fiber ropes, which are inorganic materials and have non-combustible properties.

[0027] The thickness of the flame retardant tape layer is 0.4-0.6mm, and it is wrapped with alkali-free glass tape; the copper wire braided layer is made of a single copper wire with a single wire outer diameter of 0.2mm and an elastic fiber rope, and the braiding density is greater than 80%, which increases the softness of the wrapping. The copper wire braiding plays a shielding role. The shielded cable with this structure can resist electromagnetic induction, poor grounding and power line conduction interference, reduce inductance, and prevent excessive induced electromotive force. The shielding layer not only suppresses the external emission of electromagnetic waves, but also serves as a channel for short-circuit current, and can protect the neutral core.

[0028] Furthermore, the copper wire braiding here adopts a double-layer structure, and an aluminum foil layer is added between the two layers.

[0029] The oxygen-insulating inner sheath is made of low-smoke halogen-free oxygen-insulating material with a thickness of 1.0 mm and an oxygen index of not less than 45. The material is filled with a large amount of hydrated metal oxides, with a filling ratio of more than 45% by volume. When heated, water molecules evaporate and absorb most of the heat, which can reduce the temperature of the cable. The formed water molecules can dilute the concentration of oxygen around the cable, and the burning metal oxide products form a hard shell, which is coated on the outside of the cable core to prevent flames and heat from spreading to the inside of the cable. At the same time, the oxygen-insulating layer acts as an isolation sleeve.

[0030] The steel tape armor layer is made of double-layer galvanized steel tapes. The width of each galvanized steel tape is 25 mm and the thickness is 0.2 mm. The two layers are wrapped with a gap, and the gap is less than 12 mm. The steel tape armor can improve the mechanical properties of the cable and enhance the impact resistance. Second, it can block the flame, protect the internal structure of the cable, and prevent the flame from spreading inside the cable.

[0031] The thickness of the fire-resistant and flame-retardant layer is 2.0 mm. It is made of a mixture of active aluminum hydroxide hydrate or magnesium hydroxide hydrate and sodium silicate. At the same time, ceramic fiber is added, where the ceramic fiber accounts for 30-60% by mass percentage, the active aluminum hydroxide hydrate or magnesium hydroxide hydrate accounts for 5-25% by mass percentage, and the sodium silicate accounts for 25-45% by mass percentage. Since the mixture contains a large amount of aluminum hydroxide hydrate (or magnesium hydroxide hydrate), a large amount of water is generated by decomposition at high temperature to form water mist, thus playing a role in cooling and fire prevention. After high temperature, a hard shell can be formed, which has good heat insulation, and the thermal conductivity is 0.09 W / Mk. Especially, the inside after ablation is a uniform honeycomb shape, which has better fire resistance and heat insulation.

[0032] In a specific embodiment, a preparation method of a fire-proof control cable is characterized in that the preparation process is as follows: a. Prepare a double-layer core. The inner and outer layer cores are respectively arranged by a plurality of conductors. The ratio of the number of conductors in the inner layer core to the number of conductors in the outer layer core is 1:4-6; b. Cable the double-layer core. The conductors of the inner layer core are arranged in cable to the left in turn, and the conductors of the outer layer core are arranged in cable to the right in turn. A glass fiber rope is filled between the inner and outer layer conductors; c. Extrude an outer sheath outside the double-layer core. The outer sheath is successively a flame-retardant tape layer, a copper wire braided layer, an oxygen-isolating inner sheath layer, a steel tape armor layer, a fire-resistant and flame-retardant layer, and an outer sheath.

[0033] Further, in step a, the core is cabled in two layers, with 1-4 cores in the inner layer and 5-14 cores in the outer layer. The cores are cabled in a clockwise direction, and the numbers are arranged in cable from small to large. In step c, the thickness of the flame-retardant tape layer is 0.4-0.6 mm and it is wrapped with an alkali-free glass tape; the copper wire braided layer is made of copper wires with a single wire outer diameter of 0.2 mm, and the braiding density is greater than 80%. In step c, the oxygen-isolating inner sheath layer is made of a low-smoke and halogen-free oxygen-isolating material with a thickness of 1.0 mm; the steel tape armor layer is made of double-layer galvanized steel tapes. The width of each galvanized steel tape is 25 mm and the thickness is 0.2 mm.

[0034] The cable of the present invention has the following advantages:

[0035] 1. The combustion performance reaches Class B1, and the additional classification meets the requirements of d0, t0, and a1. The standard requirement for flame spread is FS ≤ 1.5 m, and the measured value is 0.6 m; the standard requirement for the total heat release within 1200 s of fire exposure is THR1200 ≤ 15 MJ, and the measured value is 7 MJ; the standard requirement for the total smoke production within 1200 s of fire exposure is TSP1200 ≤ 50 m², and the measured value is 2 m²; the standard requirement for smoke density (minimum light transmittance) is It ≥ 60%, and the measured value is 65%, etc.

[0036] 2. Excellent fireproof performance: Adopting a multi-layer fireproof structure, it can quickly sinter into a hard ceramic-like shell under the flame of 650°C - 3000°C, without cracking, melting, or dripping. This shell can effectively isolate the invasion of high-temperature flames into the interior of the circuit, ensuring the smoothness of the circuit in case of a fire; when the cable is under the rated working voltage, the flame temperature is not lower than 750°C, and the fuse does not blow within 90 minutes of fire supply.

[0037] 3. Excellent electrical performance: The dielectric constant ≥ 25 MV / m, and the volume resistivity ≥ 5 × 10¹³ Ω•m; the bending strength of the hard ceramic shell after ablation can reach 6 - 8 MPa, the dielectric constant ≥ 27 MV / m, and the volume resistivity ≥ 5 × 10¹⁵ Ω•m;

[0038] 4. Good heat insulation, with a thermal conductivity of 0.09 W / Mk. Especially after ablation, the interior is a uniform honeycomb shape, with better fire resistance and heat insulation.

[0039] 5. Environmentally friendly: It contains no heavy metals, is non-toxic, odorless, and has no impact on the human body and the environment; it is ant-proof, mouse-bite-proof, waterproof, and oil-resistant.

[0040] It should be noted that for the present invention that has been fully described, there can also be various transformation and modification implementation schemes, and it is not limited to the specific embodiments of the above implementation manners. The above embodiments are only illustrative of the present invention, rather than a limitation to the present invention. In short, the protection scope of the present invention should include those transformations, substitutions, and modifications that are obvious to those of ordinary skill in the art, and shall be subject to the appended claims.

Claims

1. A fireproof control cable, characterized in that, The fireproof control cable comprises an inner conductor layer and an outer sheath wrapped around the outer conductor inner layer; the inner conductor layer is provided with a double-layer core, the double-layer core is respectively an inner core and an outer core, the inner core and the outer core are respectively arranged by a plurality of conductors, the ratio of the number of conductors of the inner core to the number of conductors of the outer core is 1:2-5, the outer sheath is sequentially a flame-retardant tape layer, a copper wire braided layer, an oxygen-isolating inner sheath, a steel belt armor layer, a fire-resistant flame-retardant layer and an outer sheath; the outer sheath of the conductor is provided with an insulating layer and a fire-resistant layer, the conductor is a copper conductor, the conductors of the inner core are sequentially arranged to the left to form a cable, the conductors of the outer core are sequentially arranged to the right to form a cable, a spiral pattern is arranged on the surface of the ceramic polyolefin insulating material, the surface of the inner core is provided with a clockwise spiral pattern, and the surface of the outer core is provided with a counterclockwise spiral thread; the copper The wire braided layer is woven from a single copper wire with an outer diameter of 0.2mm and an elastic fiber rope, with a braiding density greater than 80%. The copper wire braiding adopts a double-layer structure, and an aluminum foil layer is added between the two layers. The thickness of the fire-resistant and flame-retardant layer is 2.0mm, and it is made of a mixture of active aluminum hydroxide hydrate or magnesium hydroxide hydrate and sodium silicate, and ceramic fiber is added at the same time, wherein the ceramic fiber accounts for 30-60% by mass, the active aluminum hydroxide hydrate or magnesium hydroxide hydrate accounts for 5-25% by mass, and the sodium silicate accounts for 25-45% by mass. The oxygen-isolating inner protective layer adopts low-smoke halogen-free oxygen-isolating material with a thickness of 1.0mm. The steel belt armor layer is made of double-layer galvanized steel belt, and each layer of galvanized steel belt is 25mm wide and 0.2mm thick.

2. The fireproof control cable according to claim 1, characterized in that, The space between the inner and outer conductors is filled with glass fiber rope.

3. The fireproof control cable according to claim 1, characterized in that, The thickness of the flame retardant tape layer is 0.4-0.6mm, and it is wrapped with alkali-free glass tape.

4. A method for preparing the fireproof control cable according to claim 1, characterized in that, The preparation process is as follows: a. Prepare a double-layer wire core, where the inner and outer wire cores are respectively composed of a number of conductors arranged, and the ratio of the number of conductors of the inner wire core to the number of conductors of the outer wire core is 1:2-5; b. Cable the double-layer wire core, where the conductors of the inner wire core are arranged in sequence to the left into a cable, and the conductors of the outer wire core are arranged in sequence to the right into a cable, and glass fiber rope is filled between the inner and outer conductors; c. Extrude an outer sheath on the outside of the double-layer wire core, and the outer sheath is sequentially a flame-retardant tape layer, a copper wire braided layer, an oxygen-isolating inner sheath, a steel belt armor layer, a fire-resistant and flame-retardant layer, and an outer sheath.

5. The method for preparing the fireproof control cable according to claim 4, characterized in that, The preparation process is as follows: In step a, the wire cores are cabled in two layers, an inner layer of 1-4 cores and an outer layer of 5-14 cores, and the wire cores are arranged in a clockwise direction from small to large numbers.

6. The method for preparing the fireproof control cable according to claim 4, characterized in that, The preparation process is as follows: in step c, the thickness of the flame retardant tape layer is 0.4-0.6mm, and it is wrapped with alkali-free glass tape; the copper wire braided layer is woven with copper wire with a single wire outer diameter of 0.2mm, and the braiding density is greater than 80%.

7. The method for preparing the fireproof control cable according to claim 4, characterized in that, The preparation process is as follows: In step c, the oxygen-isolating inner protective layer is made of low-smoke halogen-free oxygen-isolating material with a thickness of 1.0 mm; the steel belt armor layer is made of double-layer galvanized steel belt, and each layer of galvanized steel belt is 25 mm wide and 0.2 mm thick.

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