Flame-retardant B1-level fire-resistant cable

Abstract

The utility model relates to the technical field of flame-retardant cables, in particular to a flame-retardant B1-level fire-resistant cable, which comprises a cable core, conductors and a filling layer, which are twisted in pairs, are wrapped and fixed by a wrapping tape to form a circular cross section; the outer wall of the wrapping tape is coated with the composite flame-retardant layer; the outer sheath is extruded on the outer wall of the composite flame-retardant layer; wherein the composite flame-retardant layer comprises at least two layers of flame-retardant structures, and each flame-retardant structure comprises a flame-retardant rope weaving layer and a mica tape wrapping layer. According to the utility model, the flame-retardant rope braid layer, the flame-retardant particles filled in the holes of the braid layer and the wrapping tape wrapping the flame-retardant rope braid layer are adopted as a flame-retardant structure, so that compared with a glass tape flame-retardant structure which is repeatedly wrapped, the flame-retardant structure has better flame-retardant effects in the radial direction and the axial direction due to the increase of the content of the flame-retardant particles in the flame-retardant structure; particularly, the integrity of the structure can be kept under a continuous heat source, and in addition, the bending performance and the diameter of the cable can be better controlled.

Description

Technical Field

[0001] The utility model relates to the technical field of flame-retardant cables, in particular to a flame-retardant B1 grade fire-resistant cable. Background Art

[0002] The basic characteristic of flame-retardant cables is that they may be burned and unable to operate in the event of a fire, but they can prevent the spread of fire. That is, when the wires are short-circuited, burned, or caught fire due to accidents, incidents, or other reasons, the burning can be limited to a local area and prevented from spreading, thereby protecting various other equipment and avoiding greater losses. It has the characteristics and capabilities to prevent or delay the occurrence or spread of flames, and is used in integrated wiring in hotels, banks, hospitals, airports, stations, factories, commercial and residential areas involving densely populated places, and places high demands on the suppression of fire spread and smoke diffusion.

[0003] The flame retardant principle of flame retardant cables is mainly achieved by suppressing the three elements that cause combustion, namely, combustible gas, heat and oxygen. In order to achieve the purpose of flame retardancy, the method generally adopted by flame retardant wires and cables is to add halides and metal oxides containing halogens to the sheath material. However, since these materials contain halides, a large amount of smoke and hydrogen halide gas will be released during combustion, which will greatly hinder the safe evacuation of personnel, personnel safety and fire fighting. In addition, once the hydrogen halide gas reacts with water in the air, "hydrogen halide acid" will be generated, which will seriously corrode instruments and equipment and buildings and cause "secondary disasters". The flame retardant problem has evolved from the past halogen flame retardant to low-halogen and halogen-free flame retardant.

[0004] At present, alkali-free glass ribbon wrapping, halogen-free flame retardant filling, glass fiber filling, etc. are usually added to the cable as flame retardant materials, or flame retardant doped polymer cable materials (as insulation layer, fireproof layer, isolation layer, sheath layer, etc.) are used to achieve flame retardant effect. At the same time, low-halogen halogen-free cable materials are used to achieve smoke suppression effect and reduce casualties in the event of a fire. The glass ribbon has good flame retardant ability and does not burn, but it is easy to melt at high temperature, so that it cannot be maintained in a specific position. The repeated wrapping of glass ribbon and mica tape will increase the diameter of the cable. The prior art attempts to improve the mechanical bending performance and flame retardant effect by constructing a composite wrapping tape with anisotropic cross-section, but the overlap rate of the wrapping tape is high and the stress generated at the stacking point is large. Summary of the invention

[0005] In view of the technical problems existing in flame-retardant cables in the prior art, the first aspect of the utility model proposes a flame-retardant B1-class fire-resistant cable, comprising:

[0006] The conductors twisted in pairs and the filling layer are wrapped with a wrapping tape to form a cable core with a circular cross-section;

[0007] A composite flame retardant layer coated on the outer wall of the wrapping tape;

[0008] An outer sheath, extruded and wrapped around the outer wall of the composite flame retardant layer;

[0009] Wherein, the composite flame retardant layer comprises at least two flame retardant structures in a stacked distribution manner, and adjacent flame retardant structures are arranged with heterogeneous weaving density;

[0010] Each of the flame-retardant structures includes a flame-retardant rope braided layer and a mica tape wrapping layer. The flame-retardant rope braided layer is wrapped around the outer wall of the wrapping tape. The braiding density of the flame-retardant rope braided layer is 60%-80%. Flame-retardant particles are arranged in the pores of the flame-retardant rope braided layer. The mica tape wrapping layer is coated on the outer wall of the flame-retardant rope braided layer.

[0011] Preferably, the wrapping tape comprises a copper tape wrapping tape.

[0012] Preferably, the wrapping overlap rate of the copper tape is greater than 40%.

[0013] Preferably, the flame retardant rope braided layer comprises flame retardant ropes woven in a mesh shape, and the diameter of the flame retardant ropes is 2-3 mm.

[0014] Preferably, the mica tape wrapping layer comprises a phlogopite tape wrapping layer, and the thickness of the phlogopite tape is 1.5-2 mm.

[0015] Preferably, the wrapping overlap rate of the phlogopite tape is 30-50%.

[0016] Preferably, the composite flame retardant layer includes two layers of the flame retardant structure, the first layer of flame retardant structure is located on the inner side of the second layer of flame retardant structure, the weaving density of the first flame retardant rope braided layer of the first layer of flame retardant structure is less than the weaving density of the second flame retardant rope braided layer in the second layer of flame retardant structure, and the wrapping overlap rate of the first mica tape wrapping layer of the first layer of flame retardant structure is less than the wrapping overlap rate of the second mica tape wrapping layer in the second layer of flame retardant structure.

[0017] Preferably, the braiding density of the first flame-retardant rope braided layer is 60%, and the wrapping overlap of the first mica tape wrapping layer is 30%;

[0018] The braiding density of the flame retardant rope braided layer of the second flame retardant rope braided layer is 80%, and the wrapping overlap of the second mica tape wrapping layer is 50%.

[0019] As an optional implementation, the outer sheath adopts a halogen-free low-smoke polyolefin sheath layer.

[0020] Compared with the prior art, the B1 grade flame retardant and fire resistant cable of the utility model adopts a flame retardant rope braided layer, flame retardant particles filled into the pores of the braided layer, and a wrapping tape wrapped around the flame retardant rope braided layer as a flame retardant structure. Compared with the repeatedly wrapped glass ribbon flame retardant structure, due to the increase in the content of flame retardant particles in the flame retardant structure, the comprehensive improvement forms a better flame retardant effect in both radial and axial directions, especially under a continuous heat source, the integrity of the structure can be maintained, and the bending performance and diameter of the cable can be better controlled. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings are not intended to be drawn to scale. In the accompanying drawings, each identical or approximately identical component shown in each figure may be represented by the same reference numeral. For clarity, not every component is labeled in each figure. Now, embodiments of various aspects of the utility model will be described by way of example and with reference to the accompanying drawings.

[0022] Figure 1 It is a structural schematic diagram of the flame-retardant B1 grade fire-resistant cable shown in the utility model.

[0023] Figure 2 It is a structural schematic diagram of the composite flame retardant layer shown in the utility model. DETAILED DESCRIPTION

[0024] In order to better understand the technical content of the present invention, specific embodiments are described below in conjunction with the accompanying drawings.

[0025] Combination Figure 1 As shown, the flame-retardant B1 class fire-resistant cable according to an exemplary embodiment of the utility model includes a cable core, a composite flame-retardant layer and an outer sheath 8.

[0026] Optionally, the conductors 1 twisted in pairs and the filling layer 2 are wrapped with a wrapping tape 3 to form a cable core with a circular cross-section. For example, three, four or seven wire cores and a flame retardant filling rope are wrapped with a wrapping tape 3 to form a cable core.

[0027] In an optional embodiment, the conductor 1 includes a conductor core, an inner shielding layer and an insulating layer. The conductor core can be formed by 1+6 or 1+6+12 regular twisted aluminum alloy or copper wire, the inner shielding layer and the insulating layer are formed by double-layer co-extrusion, and the insulating layer is made of irradiated cross-linked polyethylene to ensure good insulation performance. In addition, the outer wall of the twisted conductor core can also be formed by a three-layer co-extrusion process to form a structure including inner and outer shielding layers and an insulating layer.

[0028] In an optional embodiment, the wrapping tape 3 is tightly wrapped with a copper tape, and the wrapping overlap rate is controlled to be 40%-50%. The copper tape is tightly wrapped to ensure that the cross-section of the cable is round, the density is high, and the shielding performance is good.

[0029] Furthermore, the composite flame retardant layer is coated on the outer wall of the wrapping tape 3, and the outer sheath 8 is extruded on the outer wall of the composite flame retardant layer, wherein the composite flame retardant layer includes at least two layers of flame retardant structure. In an embodiment of the utility model, at least two layers of flame retardant structures are used in a stacked distribution manner, and adjacent flame retardant structures are arranged with heterogeneous weaving density.

[0030] According to the strength shown in the figure, each flame retardant structure includes a flame retardant rope braided layer and a mica tape wrapped layer, the flame retardant rope braided layer is wrapped around the outer wall of the wrapping tape 3, the braiding density of the flame retardant rope braided layer is 60%-80%, and flame retardant particles are arranged in the pores of the flame retardant rope braided layer. The mica tape wrapped layer is coated on the outer wall of the flame retardant rope braided layer.

[0031] In an optional embodiment, the flame retardant rope braided layer is formed by braiding a flame retardant rope mesh, and the flame retardant rope can be glass fiber rope or aramid fiber rope. Flame retardant particles, such as at least one of inorganic metal oxides (aluminum hydroxide, magnesium hydroxide, etc.) or ceramic particles, are filled in the pores of the flame retardant rope braided layer to form mixed particles with nylon particles, and the particle size of the particles is 0.05-0.1m. Nylon particles are elastic and can provide deformation space for other hard particles when the cable is bent.

[0032] During the processing, after the wrapping tape 3 is wrapped, a flame retardant rope braided layer is weaved on the surface of the wrapping tape 3 using a weaving device, and then the cable with the woven flame retardant rope braided layer is passed through a box with mixed particles, so that the mixed particles are evenly distributed in the pores of the flame retardant rope braided layer, and then a mica tape is used to wrap the surface of the flame retardant rope braided layer to form a mica tape wrapping layer to wrap and limit the mixed particles.

[0033] The flame-retardant structure formed in this way has simple processing methods, good bending performance, and good flame-retardant performance. When subjected to open flames, the flame-retardant rope and mixed particles are both flame-retardant materials, and will not burn under continuous heat. Moreover, through the isolation of the mica tape, it has a good barrier effect on open flames.

[0034] In an optional embodiment, the flame retardant rope braided layer includes a flame retardant rope braided in a mesh shape, and the diameter of the flame retardant rope is 2-3 mm. The mica tape wrapping layer includes a phlogopite mica tape wrapping layer, and the thickness of the phlogopite mica tape is 1.5-2 mm. The wrapping overlap rate of the phlogopite mica tape is 30-50%.

[0035] like Figure 2 As shown, the composite flame retardant layer includes two layers of flame retardant structure, the first layer of flame retardant structure is located on the inner side of the second layer of flame retardant structure, the weaving density of the first flame retardant rope braided layer 4 of the first layer of flame retardant structure is less than the weaving density of the second flame retardant rope braided layer 6 in the second layer of flame retardant structure, and the wrapping overlap rate of the first mica tape wrapping layer 5 of the first layer of flame retardant structure is less than the wrapping overlap rate of the second mica tape wrapping layer 7 in the second layer of flame retardant structure.

[0036] In a specific embodiment, the weaving density of the first flame retardant rope braided layer 4 is 60%, the wrapping overlap rate of the first mica tape wrapping layer 5 is 30%, the weaving density of the flame retardant rope braided layer 6 is 80%, and the wrapping overlap rate of the second mica tape wrapping layer 7 is 50%.

[0037] In this way, the mica tape of the flame retardant structure in the outer layer is tightly wrapped, while the content of flame retardant particles in the flame retardant structure in the inner layer is high, which can form a good flame retardant effect.

[0038] The outer sheath 8 adopts a halogen-free low-smoke polyolefin sheath layer. When the halogen-free low-smoke polyolefin sheath is burned, no halogen acid gas is released, and the amount of toxic and corrosive gas released is extremely small, and the smoke concentration generated is extremely low.

[0039] In combination with the above embodiments, the utility model adopts a flame retardant rope braided layer, flame retardant particles filled into the pores of the braided layer, and a wrapping tape wrapped around the flame retardant rope braided layer as a flame retardant structure. Compared with the repeatedly wrapped glass ribbon flame retardant structure, due to the increase in the content of flame retardant particles in the flame retardant structure, a better flame retardant effect is formed in both the radial and axial directions, especially under a continuous heat source, the integrity of the structure can be maintained. In addition, the bending performance and diameter of the cable can be better controlled.

[0040] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. A person with ordinary knowledge in the technical field to which the present invention belongs may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the definition of the claims.

Claims

1. A flame retardant B1 grade fire resistant cable, characterized in that: include: The conductors (1) twisted in pairs and the filling layer (2) are wrapped with a wrapping tape (3) to form a cable core with a circular cross-section; A composite flame retardant layer, coated on the outer wall of the wrapping tape (3); An outer sheath (8) extruded onto the outer wall of the composite flame retardant layer; Wherein, the composite flame retardant layer comprises at least two flame retardant structures in a stacked distribution manner, and adjacent flame retardant structures are arranged with heterogeneous weaving density; Each of the flame retardant structures comprises a flame retardant rope braided layer and a mica tape wrapping layer, the flame retardant rope braided layer is wrapped around the outer wall of the wrapping tape (3), the braiding density of the flame retardant rope braided layer is 60%-80%, flame retardant particles are arranged in the pores of the flame retardant rope braided layer, and the mica tape wrapping layer is coated on the outer wall of the flame retardant rope braided layer.

2. The flame-retardant B1-class fire-resistant cable according to claim 1, characterized in that: The wrapping tape (3) comprises a copper tape wrapping tape.

3. The flame-retardant B1-class fire-resistant cable according to claim 2, characterized in that: The wrapping overlap rate of the copper tape wrapping tape is greater than 40%.

4. The flame-retardant B1-class fire-resistant cable according to claim 1, characterized in that: The flame retardant rope braided layer comprises flame retardant ropes woven in a mesh shape, and the diameter of the flame retardant ropes is 2-3 mm.

5. The flame-retardant B1-class fire-resistant cable according to claim 1, characterized in that: The mica tape wrapping layer includes a phlogopite tape wrapping layer, and the thickness of the phlogopite tape is 1.5-2 mm.

6. The flame-retardant B1-class fire-resistant cable according to claim 5, characterized in that: The wrapping overlap rate of the phlogopite tape is 30-50%.

7. The flame-retardant B1-class fire-resistant cable according to any one of claims 1 to 6, characterized in that: The composite flame retardant layer comprises two layers of the flame retardant structure: the first flame retardant structure is located on the inner side of the second flame retardant structure, and the braiding density of the first flame retardant rope braided layer (4) of the first flame retardant structure is smaller than the braiding density of the second flame retardant rope braided layer (6) of the second flame retardant structure.

8. The flame-retardant B1-class fire-resistant cable according to claim 7, characterized in that: The wrapping overlap rate of the first mica tape wrapping layer (5) of the first flame retardant structure is less than the wrapping overlap rate of the second mica tape wrapping layer (7) of the second flame retardant structure.

9. The flame-retardant B1-class fire-resistant cable according to claim 8, characterized in that: The braiding density of the first flame-retardant rope braided layer (4) is 60%, and the wrapping overlap of the first mica tape wrapping layer (5) is 30%; The braiding density of the second flame retardant rope braided layer (6) is 80%, and the wrapping overlap of the second mica tape wrapping layer (7) is 50%.

10. The flame-retardant B1-class fire-resistant cable according to claim 1, characterized in that: The outer sheath (8) adopts a halogen-free low-smoke polyolefin sheath layer.

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