A flame retardant B1 grade cable

Abstract

The present invention discloses a flame-retardant B1-class cable, the cable having a cable core mainly composed of a plurality of insulated conductors, the cable core being coated with an inner ceramic fiber tape layer, an oxygen-isolating layer, an outer ceramic fiber tape layer and a sheath layer in sequence from the inside to the outside, and a ceramic fiber cotton filling layer being filled in the combined gap of the cable core coated with the inner ceramic fiber tape layer. The present invention forms a multi-layer protection for the insulated conductors of the cable core through such a structural arrangement to prevent the flame from burning inside the cable core, and at the same time, can prevent external heat from being conducted to the insulated conductors of the cable core to the greatest extent, and has the characteristics of good fireproofing and fireproofing performance and excellent flame retardant effect.

Description

Technical Field

[0001] The invention relates to a power cable, in particular to a power cable capable of passing a flame retardant B1 level test. Background Art

[0002] Cables are classified into common cables, flame-retardant cables, and fire-resistant cables according to their combustion characteristics. Flame-retardant cables can be classified into four flame-retardant grades: A, B, C, and D according to the classification of their combustion performance. Commonly used flame-retardant cables are manufactured in accordance with the technical standards of GB / T 19666-2005 "General Rules for Flame-retardant and Fire-resistant Cables", and have been widely used in national economic construction.

[0003] However, during the combustion process of a fire, the flame temperature usually reaches about 750°C or even about 950°C. The temperature resistance level of the glass fiber filling layer and the glass fiber tape layer of the above-mentioned flame retardant cable cannot adapt to this combustion temperature and is very easy to burn. The residue after burning is very brittle and is easy to fall off with a slight touch or vibration. It cannot effectively prevent the flame or temperature from burning and transmitting internally, and cannot protect the inner insulation layer with poor flame retardant performance. This causes the burning of the insulation layer material (because most of the insulation materials are flammable organic matter), and finally causes the entire cable to continue to burn, releasing a large amount of heat and smoke, and cannot ensure fire safety.

[0004] With the rapid and steady development of national key subway projects, especially the densely populated and congested subway stations, once there are signs of fire, it will not only cause losses to national property, but more seriously threaten the lives of many people. For this reason, the state issued the mandatory national standard GB 31247-2014 "Classification of Combustion Performance of Electric Cables and Optical Cables" on December 5, 2014. In this technical standard, by quantifying the technical indicators of the classification of combustion performance of electric cables and optical cables, it makes fire safety more scientific and reasonable, and minimizes the possible fire hazards.

[0005] Obviously, the above-mentioned commonly used flame-retardant cables are difficult to meet the increasingly stringent and more scientific and reasonable technical standards, and cannot adapt to the development needs of the market and technology. It is necessary to improve them. Summary of the invention

[0006] The technical purpose of the present invention is to provide a flame retardant B1 grade cable with good fireproofing and fire isolation performance and excellent flame retardant effect in view of the deficiencies of the above-mentioned prior art.

[0007] The technical purpose of the present invention is achieved through the following technical scheme: a flame-retardant B1 grade cable, the cable having a cable core mainly composed of multiple insulated conductors, the cable core is sequentially coated with an inner ceramic fiber tape layer, an oxygen isolation layer, an outer ceramic fiber tape layer and a sheath layer from the inside to the outside, and the combined gap of the cable core coated by the inner ceramic fiber tape layer is filled with a ceramic fiber cotton filling layer.

[0008] As one of the preferred solutions, a mirror metal composite tape layer is coated between the inner ceramic fiber tape layer and the oxygen-isolating layer. Further, the mirror metal composite tape layer is at least one layer of a wrapped structure of a mirror aluminum-plastic composite tape.

[0009] As one of the preferred solutions, the inner ceramic fiber tape layer is at least one layer of wrapped structure of ceramic fiber tape.

[0010] As one of the preferred solutions, a cooling layer is coated between the oxygen-isolating layer and the outer ceramic fiber belt layer, and the cooling layer is a molding structure in which aluminum hydroxide or magnesium hydroxide filler is filled in a hollow cavity. Further, the cooling layer is composed of a plurality of hollow tubes arranged circumferentially and fillers filled in each hollow tube.

[0011] As one of the preferred solutions, the oxygen barrier layer is an extruded layer structure of low-smoke halogen-free polyolefin.

[0012] As one of the preferred solutions, the outer ceramic fiber tape layer is at least one layer of wrapped structure of ceramic fiber tape.

[0013] As one of the preferred solutions, the sheath layer is an extruded layer structure of low-smoke halogen-free flame-retardant polyolefin.

[0014] As one of the preferred solutions, the multiple insulated conductors of the cable core are twisted together, and the twisted gap is filled with a ceramic fiber cotton filling layer. Further, each insulated conductor of the cable core is mainly composed of a conductor and an insulating layer coated on the conductor, and the conductor is a type 1 copper conductor, a type 2 copper conductor or a type 5 soft copper conductor in standard GB / T 3956, and the insulating layer is an extruded layer structure of irradiated cross-linked polyolefin. Further, the conductor of the insulated conductor is a single copper wire structure or a multi-strand copper wire twisted structure.

[0015] The beneficial technical effects of the present invention are:

[0016] 1. The ceramic fiber material used in the present invention is an aluminum silicate refractory fiber, which is made of hard clay clinker or industrial alumina powder and silica powder as raw materials, melted in an electric arc furnace or a resistance furnace, and formed into fibers by compressed air blowing (or spinning method). Its chemical composition is mainly aluminum oxide (30-55%) and silicon dioxide. After reprocessing and molding, it has the characteristics of low heat capacity, low thermal conductivity, excellent thermal stability, and high temperature resistance of more than 1000°C. It will not burn itself. The present invention uses this material to fill the combined gap of the cable core, and reasonably arranges the inner ceramic fiber belt layer, oxygen isolation layer, outer ceramic fiber belt layer, etc. outside the cable core. Through this structural arrangement, the insulating conductor of the cable core is formed with multiple layers of protection to prevent the flame from burning inside the cable core, and at the same time, it can prevent the external heat from being conducted to the insulating conductor of the cable core to the greatest extent. In short, it is very beneficial to reduce the total heat release index of the cable. The flame-retardant cable of the present invention can effectively meet the GB 31247-2014 Technical standard of "Classification of Combustion Performance of Electrical Cables and Optical Cables", with good fireproofing and fireproofing performance and excellent flame retardant effect;

[0017] 2. The mirror metal composite tape layer coated between the inner ceramic fiber tape layer and the oxygen-insulating layer of the present invention can reflect most of the heat to reduce the temperature impact of external heat on the internal structural parts, and further effectively prevent the external heat from being conducted to the insulated conductor of the cable core. This is particularly evident in the structure in which the mirror metal composite tape layer of the present invention is wrapped with a mirror aluminum-plastic composite tape, because the surface of the mirror aluminum-plastic composite tape has an excellent reflective effect as a heat reflective layer;

[0018] 3. The cooling layer coated between the oxygen-isolating layer and the outer ceramic fiber tape layer of the present invention can decompose the filler aluminum hydroxide or magnesium hydroxide into aluminum oxide / magnesium oxide and water (H2O) during the cable combustion process. The presence of water effectively reduces the flame temperature and prevents combustion, further effectively improving its fireproof and flame retardant effects;

[0019] 4. The arrangement structure of the hollow tubes in the cooling layer of the present invention can achieve a dense and compact arrangement with high strength and good integrity. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a structural schematic diagram of the present invention. As can be seen from the figure, the cable core is mainly composed of four insulated conductors, each of which is mainly composed of a conductor and an insulating layer coated on the conductor; the cable core is coated with an inner ceramic fiber tape layer, a mirror metal composite tape layer, an oxygen isolation layer, an outer ceramic fiber tape layer and a sheath layer in sequence from the inside to the outside; and a ceramic fiber cotton filling layer is filled in the combined gap of the cable core coated with the inner ceramic fiber tape layer.

[0021] Figure 2This is another structural schematic diagram of the present invention. As can be seen from the figure, the cable core is mainly composed of four insulated conductors, each of which is mainly composed of a conductor and an insulating layer coated on the conductor; the cable core is coated with an inner ceramic fiber tape layer, a mirror metal composite tape layer, an oxygen isolation layer, a cooling layer, an outer ceramic fiber tape layer and a sheath layer in sequence from the inside to the outside; a ceramic fiber cotton filling layer is filled in the combined gap of the cable core coated with the inner ceramic fiber tape layer; the cooling layer is composed of a plurality of circumferentially arranged tubular structures with fillers.

[0022] Figure 3 for Figure 2 An enlarged schematic diagram of the composition structure of the middle cooling layer. It can be seen from the figure that the units constituting the cooling layer are hollow tubes and fillers filled therein.

[0023] The meaning of the codes in the figure are: 1—conductor; 2—insulating layer; 3—ceramic fiber cotton filling layer; 4—inner ceramic fiber belt layer; 5—mirror metal composite belt layer; 6—oxygen insulation layer; 7—cooling layer; 71—hollow tube; 72—filler; 8—outer ceramic fiber belt layer; 9—sheath layer. DETAILED DESCRIPTION

[0024] The present invention relates to a power cable, specifically a power cable that can pass the flame retardant B1 test. The main technical content of the present invention is described in detail with multiple embodiments. Figure 1 The technical solution of the present invention is clearly and in detail explained, and Example 5 is combined with the accompanying drawings of the specification - that is, Figure 2 and Figure 3 The technical solution of the present invention is explained clearly and in detail. Although other embodiments are not separately illustrated with drawings, their main structures can still refer to the drawings of Embodiment 1.

[0025] It should be particularly noted that the drawings of the present invention are schematic, and unnecessary details have been simplified to clarify the technical purpose of the present invention so as to avoid blurring the technical solution that the present invention contributes to the prior art.

[0026] See also Figure 1 As shown, the present invention has a twisted cable core, on which an inner ceramic fiber tape layer 4, a mirror metal composite tape layer 5, an oxygen barrier layer 6, an outer ceramic fiber tape layer 8 and a sheath layer 9 are sequentially coated from the inside to the outside, and a ceramic fiber cotton filling layer 3 is filled in the combined gap of the cable core coated by the inner ceramic fiber tape layer 4, and the cable core is filled with the ceramic fiber cotton filling layer 3 in a whole circle.

[0027] The cable core has four insulated conductors. Each insulated conductor of the cable core is mainly composed of a conductor 1 and an insulating layer 2 coated on the conductor 1. The conductor 1 is the first type of copper conductor in the standard GB / T 3956, which is a single-strand copper wire structure; the insulating layer 2 is an extruded layer structure of irradiated cross-linked polyolefin. The four insulated conductors of the cable core are combined together in a twisted manner, and the twisted gaps of the four insulated conductors are filled with a ceramic fiber cotton filling layer 3, so that the cable core is densely filled.

[0028] The inner ceramic fiber tape layer 4 is a densely wrapped structure of the ceramic fiber tape.

[0029] The mirror metal composite tape layer 5 is a two-layer dense wrapping structure of mirror aluminum-plastic composite tape.

[0030] The oxygen barrier layer 6 is an extruded layer structure of low-smoke halogen-free polyolefin. The low-smoke halogen-free polyolefin material used in the oxygen barrier layer 6 is a polyolefin-based material filled with a large amount of inorganic flame retardants, which can reduce the organic content to the greatest extent and make the oxygen index of the material reach 45%, thereby greatly improving the flame retardant performance of the material to play the role of oxygen isolation, heat insulation and smoke suppression.

[0031] The outer ceramic fiber tape layer 8 is a densely wrapped structure of the ceramic fiber tape.

[0032] The sheath layer 9 is an extruded layer structure of irradiated flame-retardant low-smoke halogen-free polyolefin, and can certainly be replaced by non-irradiated low-smoke halogen-free polyolefin material.

[0033] The ceramic fiber cotton filling layer, the inner ceramic fiber belt layer and the outer ceramic fiber belt layer of the present invention are respectively formed by ceramic fiber materials, and the ceramic fiber material is a kind of aluminum silicate refractory fiber, which is made of hard clay clinker or industrial alumina powder and silica powder synthesis material as raw materials, melted by electric arc furnace or resistance furnace, and formed into fibers by compressed air blowing (or spinning method), and its chemical composition is mainly aluminum oxide (30-55%) and silicon dioxide. After reprocessing and forming, it has the characteristics of low heat capacity, low thermal conductivity, excellent thermal stability, and high temperature resistance of more than 1000°C, and it will not burn itself. It should be specially noted that the ceramic fiber material is an existing finished product material, and the contribution of the present invention to the prior art is not the material itself.

[0034] The present invention has a twisted cable core, on which an inner ceramic fiber tape layer, a mirror metal composite tape layer, an oxygen isolation layer, an outer ceramic fiber tape layer and a sheath layer are sequentially coated from the inside to the outside, and a ceramic fiber cotton filling layer is filled in the combined gap of the cable core coated with the inner ceramic fiber tape layer, and the cable core is filled with the ceramic fiber cotton filling layer in an entire circle.

[0035] The cable core has four insulated conductors. Each insulated conductor of the cable core is mainly composed of a conductor and an insulating layer coated on the conductor. The conductor is the second type of copper conductor in the standard GB / T 3956, which is a multi-strand copper wire twisted structure; the insulating layer is an extruded layer structure of irradiated cross-linked polyolefin. The four insulated conductors of the cable core are combined together in a twisted manner, and the twisted gaps of the four insulated conductors are filled with a ceramic fiber cotton filling layer to make the cable core densely filled.

[0036] The inner ceramic fiber tape layer is a two-layer densely wrapped structure of ceramic fiber tape.

[0037] The mirror metal composite tape layer is a three-layer dense wrapping structure of the mirror aluminum-plastic composite tape.

[0038] The oxygen barrier layer is an extruded layer structure of low-smoke halogen-free polyolefin. The low-smoke halogen-free polyolefin material used in the oxygen barrier layer is a polyolefin-based material filled with a large amount of inorganic flame retardants, which can reduce the organic content to the greatest extent and make the oxygen index of the material reach 45%, thereby greatly improving the flame retardant performance of the material, thereby playing the role of oxygen isolation, heat insulation and smoke suppression.

[0039] The outer ceramic fiber tape layer is a densely wrapped structure of the ceramic fiber tape.

[0040] The sheath layer is an extruded layer structure of irradiated flame retardant low-smoke halogen-free polyolefin, and of course, it can also be replaced by non-irradiated low-smoke halogen-free polyolefin material.

[0041] The present invention has a twisted cable core, on which an inner ceramic fiber tape layer, a mirror metal composite tape layer, an oxygen isolation layer, an outer ceramic fiber tape layer and a sheath layer are sequentially coated from the inside to the outside, and a ceramic fiber cotton filling layer is filled in the combined gap of the cable core coated with the inner ceramic fiber tape layer, and the cable core is filled with the ceramic fiber cotton filling layer in an entire circle.

[0042] The cable core has four insulated conductors. Each insulated conductor of the cable core is mainly composed of a conductor and an insulating layer coated on the conductor. The conductor is the fifth type of soft copper conductor in the standard GB / T 3956, which is a multi-strand copper wire twisted structure; the insulating layer is an extruded layer structure of irradiated cross-linked polyolefin. The four insulated conductors of the cable core are combined together in a twisted manner, and the twisted gaps of the four insulated conductors are filled with a ceramic fiber cotton filling layer to make the cable core densely filled.

[0043] The inner ceramic fiber tape layer is a densely wrapped structure of the ceramic fiber tape.

[0044] The mirror metal composite tape layer is a two-layer dense wrapping structure of mirror aluminum-plastic composite tape.

[0045] The oxygen barrier layer is an extruded layer structure of low-smoke halogen-free polyolefin. The low-smoke halogen-free polyolefin material used in the oxygen barrier layer is a polyolefin-based material filled with a large amount of inorganic flame retardants, which can reduce the organic content to the greatest extent and make the oxygen index of the material reach 45%, thereby greatly improving the flame retardant performance of the material, thereby playing the role of oxygen isolation, heat insulation and smoke suppression.

[0046] The outer ceramic fiber tape layer is a two-layer densely wrapped structure of the ceramic fiber tape.

[0047] The sheath layer is an extruded layer structure of irradiated flame retardant low-smoke halogen-free polyolefin, and of course, it can also be replaced by non-irradiated low-smoke halogen-free polyolefin material.

[0048] The present invention has a twisted cable core, on which an inner ceramic fiber tape layer, an oxygen isolation layer, an outer ceramic fiber tape layer and a sheath layer are sequentially coated from the inside to the outside, and a ceramic fiber cotton filling layer is filled in the combined gap of the cable core coated with the inner ceramic fiber tape layer, and the cable core is filled with the ceramic fiber cotton filling layer in a whole circle.

[0049] The cable core has four insulated conductors. Each insulated conductor of the cable core is mainly composed of a conductor and an insulating layer coated on the conductor. The conductor is the second type of copper conductor in the standard GB / T 3956, which is a multi-strand copper wire twisted structure; the insulating layer is an extruded layer structure of irradiated cross-linked polyolefin. The four insulated conductors of the cable core are combined together in a twisted manner, and the twisted gaps of the four insulated conductors are filled with a ceramic fiber cotton filling layer to make the cable core densely filled.

[0050] The inner ceramic fiber tape layer is a three-layer densely wrapped structure of the ceramic fiber tape.

[0051] The oxygen barrier layer is an extruded layer structure of low-smoke halogen-free polyolefin. The low-smoke halogen-free polyolefin material used in the oxygen barrier layer is a polyolefin-based material filled with a large amount of inorganic flame retardants, which can reduce the organic content to the greatest extent and make the oxygen index of the material reach 45%, thereby greatly improving the flame retardant performance of the material, thereby playing the role of oxygen isolation, heat insulation and smoke suppression.

[0052] The outer ceramic fiber tape layer is a three-layer densely wrapped structure of the ceramic fiber tape.

[0053] The sheath layer is an extruded layer structure of irradiated flame retardant low-smoke halogen-free polyolefin, and of course, it can also be replaced by non-irradiated low-smoke halogen-free polyolefin material.

[0054] See also Figure 2 and Figure 3As shown, the present invention has a twisted cable core, on which an inner ceramic fiber tape layer 4, a mirror metal composite tape layer 5, an oxygen insulation layer 6, a cooling layer 7, an outer ceramic fiber tape layer 8 and a sheath layer 9 are sequentially coated from the inside to the outside, and a ceramic fiber cotton filling layer 3 is filled in the combined gap of the cable core coated by the inner ceramic fiber tape layer 4, and the cable core is filled with the ceramic fiber cotton filling layer 3 in a whole circle.

[0055] The cable core has four insulated conductors. Each insulated conductor of the cable core is mainly composed of a conductor 1 and an insulating layer 2 coated on the conductor 1. The conductor 1 is the first type of copper conductor in the standard GB / T 3956, which is a single-strand copper wire structure; the insulating layer 2 is an extruded layer structure of irradiated cross-linked polyolefin. The four insulated conductors of the cable core are combined together in a twisted manner, and the twisted gaps of the four insulated conductors are filled with a ceramic fiber cotton filling layer 3, so that the cable core is densely filled.

[0056] The inner ceramic fiber tape layer 4 is a densely wrapped structure of the ceramic fiber tape.

[0057] The mirror metal composite tape layer 5 is a two-layer dense wrapping structure of mirror aluminum-plastic composite tape.

[0058] The oxygen barrier layer 6 is an extruded layer structure of low-smoke halogen-free polyolefin. The low-smoke halogen-free polyolefin material used in the oxygen barrier layer 6 is a polyolefin-based material filled with a large amount of inorganic flame retardants, which can reduce the organic content to the greatest extent and make the oxygen index of the material reach 45%, thereby greatly improving the flame retardant performance of the material to play the role of oxygen isolation, heat insulation and smoke suppression.

[0059] The cooling layer 7 is a molded structure in which aluminum hydroxide filler (or magnesium hydroxide filler) is filled in a hollow cavity. Specifically, the cooling layer 7 is composed of a plurality of small-diameter hollow tubes 71 sparsely arranged circumferentially outside the oxygen-isolating layer 6 and a filler 72 (i.e., aluminum hydroxide filler or magnesium hydroxide filler) filled in each hollow tube 71. Each hollow tube 71 is an extruded structure of flame-retardant, low-smoke, halogen-free polyolefin.

[0060] The outer ceramic fiber tape layer 8 is a densely wrapped structure of the ceramic fiber tape.

[0061] The sheath layer 9 is an extruded layer structure of irradiated flame-retardant low-smoke halogen-free polyolefin, and can certainly be replaced by non-irradiated low-smoke halogen-free polyolefin material.

[0062] The ceramic fiber cotton filling layer, the inner ceramic fiber belt layer and the outer ceramic fiber belt layer of the present invention are respectively formed by ceramic fiber materials, and the ceramic fiber material is a kind of aluminum silicate refractory fiber, which is made of hard clay clinker or industrial alumina powder and silica powder synthesis material as raw materials, melted by electric arc furnace or resistance furnace, and formed into fibers by compressed air blowing (or spinning method), and its chemical composition is mainly aluminum oxide (30-55%) and silicon dioxide. After reprocessing and forming, it has the characteristics of low heat capacity, low thermal conductivity, excellent thermal stability, and high temperature resistance of more than 1000°C, and it will not burn itself. It should be specially noted that the ceramic fiber material is an existing finished product material, and the contribution of the present invention to the prior art is not the material itself.

[0063] The above embodiments are only used to illustrate the present invention, but not to limit it. Although the present invention is described in detail with reference to the above embodiments, a person skilled in the art should understand that the specific technical solutions in the above embodiments can still be modified, or some of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the present invention.

Claims

1. A flame retardant B1 grade cable, the cable having a cable core mainly composed of a plurality of insulated conductors, characterized in that: The cable core is coated with an inner ceramic fiber tape layer (4), a mirror metal composite tape layer (5), an oxygen barrier layer (6), a cooling layer (7), an outer ceramic fiber tape layer (8) and a sheath layer (9) in sequence from the inside to the outside, and the combined gap of the cable core coated by the inner ceramic fiber tape layer (4) is filled with a ceramic fiber cotton filling layer (3); The inner ceramic fiber tape layer (4) is at least one layer of a wrapped structure of ceramic fiber tape; The mirror metal composite tape layer (5) is at least one layer of a wrapped structure of a mirror aluminum-plastic composite tape, and the surface of the mirror aluminum-plastic composite tape serves as a heat reflection layer; The oxygen barrier layer (6) is an extruded layer structure of low-smoke halogen-free polyolefin with polyolefin as the base material and filled with a large amount of inorganic flame retardant; The temperature reduction layer (7) is composed of a plurality of hollow tubes (71) sparsely arranged in a circumferential direction outside the oxygen isolation layer (6), and a filler (72) of aluminum hydroxide or magnesium hydroxide filled in each hollow tube (71); the hollow tube (71) is an extruded structure of flame-retardant, low-smoke, halogen-free polyolefin; The outer ceramic fiber tape layer (8) is at least one layer of a wrapped structure of ceramic fiber tape; The sheath layer (9) is an extruded layer structure of low-smoke, halogen-free, flame-retardant polyolefin.

2. The flame-retardant B1 grade cable according to claim 1, characterized in that: The multiple insulated conductors of the cable core are twisted together, and the twisted gaps are filled with a ceramic fiber cotton filling layer (3); Each insulated conductor of the cable core mainly consists of a conductor (1) and an insulating layer (2) coated on the conductor (1), and the insulating layer (2) is an extruded layer structure of radiation-type cross-linked polyolefin; The conductor (1) is a single copper wire structure or a multi-strand copper wire twisted structure.

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