Flame-retardant tape-coated cable protection tube

Abstract

The utility model belongs to cable protection pipe field, specifically is a kind of flame-retardant tape coated cable protection pipe, including the outer layer, middle layer and inner layer sequentially compounded from outside to inside, the outer layer is high toughness flame-retardant layer, the middle layer is flame-retardant heat-insulating layer, the inner layer is heat-sensitive adhesive layer, the outer layer, middle layer and inner layer are formed integrated structure by co-extrusion forming or hot-pressing composite process, the surface of inner layer and cable protection pipe contact is equipped with mechanical occlusion structure, the mechanical occlusion structure is dovetail groove, the flame-retardant tape inside is equipped with the convex structure matched with recess, by the high toughness flame-retardant layer of outer layer, external fire is isolated, the gradient distribution aluminium hydroxide layer of middle layer and nitrogen flame retardant layer are stage heat-absorbing decomposition and release inert gas, combine the microporous filling of inner layer graphite particle high-temperature expansion seals oxygen channel, form multistage flame-retardant barrier, realize flame self-extinguishing, significantly inhibit fire spread.

Description

Technical Field

[0001] This utility model relates to the field of cable protection pipes, specifically a flame-retardant cable protection pipe with a wrapping. Background Technology

[0002] PE cable protection pipe is a high-tech product made from high-quality high-density polyethylene resin as the main raw material, with appropriate additives, and processed by extrusion.

[0003] In the prior art, such as in publication number CN206976960U, a PE cable protection pipe is disclosed. It includes an inner insulating layer, an outer insulating layer, and a protective layer disposed between the inner and outer insulating layers. The protective layer is characterized by warp and weft threads arranged in a spiral shape with opposite spiral directions, and the warp and weft threads are made of an elastic metal material. This invention can be bent by heat and features high toughness and good load-bearing capacity.

[0004] Although the aforementioned patents increase the toughness of the protective tube by setting warp and weft threads, they lack active fire protection and cannot suppress the spread of flames, making them prone to accelerated combustion in the event of a fire. At the same time, the non-modular and detachable design greatly increases the efficiency and cost of local maintenance and replacement. Therefore, a flame-retardant cable protection tube with a wrapping is proposed to address the above problems. Utility Model Content

[0005] To address the shortcomings of existing technologies and the problems associated with cable protection pipes, this utility model proposes a flame-retardant tape-coated cable protection pipe.

[0006] The technical solution adopted by this utility model to solve its technical problem is as follows: The flame-retardant tape-wrapped cable protection pipe of this utility model includes an outer layer, a middle layer and an inner layer that are sequentially composited from the outside to the inside. The outer layer is a high-toughness flame-retardant layer, the middle layer is a flame-retardant and heat-insulating layer, and the inner layer is a heat-sensitive adhesive layer. The outer layer, the middle layer and the inner layer are formed into an integrated structure by co-extrusion molding or hot-pressing composite process. The surface of the inner layer that contacts the cable protection pipe is provided with a mechanical interlocking structure. The mechanical interlocking structure is a dovetail groove. The inner side of the flame-retardant tape is provided with a protrusion structure that matches the groove.

[0007] Preferably, the intermediate layer includes an aluminum hydroxide layer and a nitrogen-based flame retardant layer, and the nitrogen-based flame retardant layer is distributed in a gradient along the thickness direction, with the concentration of the aluminum hydroxide layer decreasing from the outer layer to the inner layer and the concentration of the nitrogen-based flame retardant layer increasing from the outer layer to the inner layer.

[0008] Preferably, the outer high-toughness flame-retardant layer is a modified polyvinyl chloride layer.

[0009] Preferably, the intermediate layer is further composited with a silicone rubber-based ceramic flame retardant layer, and the silicone rubber-based ceramic flame retardant layer is bonded to the intermediate layer by hot pressing.

[0010] Preferably, the surface of the inner heat-sensitive adhesive layer has a microporous structure, and the micropores are filled with expanded graphite particles.

[0011] Preferably, the groove depth of the mechanical interlocking structure matches the height of the protrusion structure, forming an interference fit.

[0012] The advantages of this utility model are:

[0013] 1. This utility model isolates external fire sources through an outer high-toughness flame-retardant layer, while the middle layer of gradient-distributed aluminum hydroxide layer and nitrogen-based flame retardant layer absorb heat and decompose in stages to release inert gas. Combined with the inner layer of microporous expanded graphite particles that expand at high temperature and seal oxygen channels, a multi-level flame-retardant barrier is formed, which realizes self-extinguishing of flames and significantly inhibits the spread of fire.

[0014] 2. The dovetail groove mechanical interlocking structure and the interference fit design of the matching protrusion structure in the inner layer of this utility model allow for quick disassembly and assembly of the flame-retardant strip and cable protection tube, supporting partial replacement or repair, avoiding the high cost of traditional whole replacement, and improving maintenance efficiency and service life. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0017] Figure 2 This is a schematic diagram of the intermediate layer structure of this utility model;

[0018] Figure 3 This is a schematic diagram of the mechanical interlocking structure and the protrusion structure of this utility model;

[0019] Figure 4 This is a schematic diagram of the disassembled structure of this utility model.

[0020] In the diagram: 1. Outer layer; 2. Middle layer; 21. Aluminum hydroxide layer; 22. Nitrogen-based flame retardant layer; 23. Silicone rubber-based ceramic flame retardant layer; 3. Inner layer; 31. Expanded graphite particles; 4. Cable protection tube; 5. Mechanical interlocking structure; 6. Raised structure. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0022] Please see Figures 1-4 As shown, a flame-retardant cable protection pipe with a protective sheath includes an outer layer 1, a middle layer 2, and an inner layer 3, which are sequentially laminated from the outside to the inside. The outer layer 1 is a high-toughness flame-retardant layer, the middle layer 2 is a flame-retardant and heat-insulating layer, and the inner layer 3 is a heat-sensitive adhesive layer. The outer layer 1, the middle layer 2, and the inner layer 3 are formed into an integrated structure by co-extrusion molding or hot-pressing composite process. The middle layer 2 includes an aluminum hydroxide layer 21 and a nitrogen-based flame retardant layer 22, and the nitrogen-based flame retardant layer 22 is distributed in a gradient along the thickness direction. The middle layer 2 is also laminated with a silicone rubber-based ceramic flame-retardant layer 23, which is bonded to the middle layer 2 by hot-pressing. The concentration of the aluminum hydroxide layer 21 decreases from the outer layer 1 to the inner layer 3, and the concentration of the nitrogen-based flame retardant layer 22 increases from the outer layer 1 to the inner layer 3. The surface of the heat-sensitive adhesive layer of the inner layer 3 is provided with a microporous structure, and the micropores are filled with expanded graphite particles 31.

[0023] During operation, the outer layer 1 is formed by co-extrusion molding of modified polyvinyl chloride to create a high-toughness flame-retardant layer. The middle layer 2 is composed of an aluminum hydroxide layer 21 and a nitrogen-based flame retardant layer 22 through hot-pressing to form a gradient distribution structure. The concentration of aluminum hydroxide layer 21 decreases from the outer layer 1 to the inner layer 3, while the concentration of nitrogen-based flame retardant layer 22 increases from the outer layer 1 to the inner layer 3. When an external flame comes into contact with the outer layer 1, the modified polyvinyl chloride blocks the initial combustion. The aluminum hydroxide layer 21 in the middle layer 2 absorbs heat and decomposes to generate water vapor, lowering the temperature. At the same time, the gradient distribution of nitrogen-based flame retardant layer 22 releases nitrogen gas at high temperature to dilute the oxygen concentration. The expanded graphite particles 31 filled in the micropores on the surface of the heat-sensitive adhesive layer of the inner layer 3 expand when heated and block the oxygen channels, forcing the flame to self-extinguish, forming a multi-level synergistic flame-retardant barrier from the outside to the inside.

[0024] Furthermore, the inner layer 3 has a mechanical interlocking structure 5 on the surface that contacts the cable protection tube 4. The mechanical interlocking structure 5 is a dovetail groove, and the inner side of the flame retardant strip has a protrusion structure 6 that matches the groove.

[0025] During operation, the raised structure 6 on the inner side of the flame-retardant strip is prefabricated with elastic silicone material to match the dovetail groove mechanical interlocking structure 5 of the inner layer 3. During installation, the raised structure 6 is pressed into the dovetail groove mechanical interlocking structure 5 by external pressure, and the interference fit is used to achieve fixation. When the flame-retardant strip needs to be replaced locally, a special pry bar is used to apply axial force to separate the raised structure 6 from the dovetail groove mechanical interlocking structure 5, and only the damaged section of the flame-retardant strip is replaced, while the intact cable protection pipe 4 and the adjacent flame-retardant strip are preserved. The silicone rubber-based ceramic flame-retardant layer 23 is hot-pressed to the surface of the intermediate layer 2, maintaining the structural integrity during disassembly and avoiding secondary damage.

[0026] Furthermore, the outermost high-toughness flame-retardant layer 1 is a modified polyvinyl chloride layer;

[0027] During operation, the high-toughness flame-retardant outer layer 1 is a modified polyvinyl chloride (PVC) layer. Specifically, PVC resin is mixed with 10-15 wt% phosphate ester plasticizer and 5-8 wt% nano-titanium dioxide anti-aging filler, and then extruded into a continuous film layer with a thickness of 0.5 mm after being blended and granulated by a twin-screw extruder. In the co-extrusion process, the modified PVC layer is directly heat-fused to the aluminum hydroxide layer 21 of the intermediate layer 2 to form a dense interface to block external fire sources and ultraviolet radiation. Its beneficial effects are reflected in the inherent flame-retardant properties of PVC combined with the flexibility enhanced by the plasticizer and the anti-aging effect of nano-titanium dioxide, so that the outer layer 1 does not crack or powder under long-term outdoor exposure, maintaining mechanical strength and flame-retardant effect, and improving weather resistance compared with traditional PE layers.

[0028] Furthermore, the groove depth of the mechanical interlocking structure 5 matches the height of the protruding structure 6, forming an interference fit;

[0029] During operation, the dovetail groove of the mechanical interlocking structure 5 is designed with a depth of 0.8mm. The protruding structure 6 on the inner side of the flame-retardant strip is molded from silicone rubber into a trapezoidal ridge with a height of 1.0mm. During installation, external force is used to compress and deform the protruding structure 6 and embed it into the groove, forming an interference fit of 0.2mm. The mating surfaces are coated with high-temperature resistant silicone grease to reduce frictional resistance. During disassembly, it can be separated without damage by prying along the groove axis. Its beneficial effect is that the interference fit makes the peel strength between the flame-retardant strip and the cable protection tube 4 ≥5N / mm, which meets the requirements of a stable connection under vibration or temperature difference deformation. At the same time, the elastic deformation characteristics of the silicone rubber protruding structure 6 support repeated disassembly and assembly without failure, which improves maintenance efficiency compared with the traditional adhesive fixing method.

[0030] Working principle: The flame-retardant tape-coated cable protection pipe uses an outer layer of modified polyvinyl chloride (PVC) to block external flames and ultraviolet rays. The middle layer 2 has a gradient distribution of aluminum hydroxide layer 21, which absorbs heat and decomposes to reduce the combustion temperature. At the same time, the nitrogen-based flame retardant layer 22 releases inert gas to dilute the oxygen concentration. The silicone rubber-based ceramic flame retardant layer 23 forms a dense ceramic layer at high temperature to isolate heat transfer. The heat-sensitive adhesive layer of the inner layer 3 is activated by heat, and the expanded graphite particles 31 filled in the micropores on its surface expand at high temperature to block the oxygen channels, forcing the flame to self-extinguish. The dovetail groove and protrusion structure 6 of the mechanical interlocking structure 5 achieve physical locking between the flame-retardant tape and the cable protection pipe 4 through interference fit, ensuring that it will not fall off in extreme environments and supporting partial disassembly and replacement. Each structural layer forms an integrated composite barrier through co-extrusion or hot pressing processes, synergistically achieving a closed loop of "flame retardant-heat insulation-self-extinguishing" functions. At the same time, the modular interlocking design takes into account long-term stability and convenient maintenance.

[0031] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, or similar improvements made within the theoretical and principle content of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A flame-retardant cable protection pipe with a sheath, characterized in that: It includes an outer layer (1), a middle layer (2) and an inner layer (3) that are sequentially composited from the outside to the inside. The outer layer (1) is a high-toughness flame-retardant layer, the middle layer (2) is a flame-retardant and heat-insulating layer, and the inner layer (3) is a heat-sensitive adhesive layer. The outer layer (1), the middle layer (2) and the inner layer (3) are formed into an integrated structure by co-extrusion molding or hot-pressing composite process. The surface of the inner layer (3) that contacts the cable protection pipe (4) is provided with a mechanical interlocking structure (5). The mechanical interlocking structure (5) is a dovetail groove. The inner side of the flame-retardant strip is provided with a protrusion structure (6) that matches the groove.

2. The flame-retardant, strip-coated cable protection pipe according to claim 1, characterized in that: The intermediate layer (2) includes an aluminum hydroxide layer (21) and a nitrogen-based flame retardant layer (22), and the nitrogen-based flame retardant layer (22) is distributed in a gradient along the thickness direction. The concentration of the aluminum hydroxide layer (21) decreases from the outer layer (1) to the inner layer (3), and the concentration of the nitrogen-based flame retardant layer (22) increases from the outer layer (1) to the inner layer (3).

3. The flame-retardant, strip-coated cable protection pipe according to claim 1, characterized in that: The high-toughness flame-retardant layer of the outer layer (1) is a modified polyvinyl chloride layer.

4. The flame-retardant, strip-coated cable protection pipe according to claim 1, characterized in that: The intermediate layer (2) is further composited with a silicone rubber-based ceramic flame retardant layer (23), which is bonded to the intermediate layer (2) by hot pressing.

5. The flame-retardant, strip-coated cable protection pipe according to claim 1, characterized in that: The inner layer (3) has a microporous structure on its surface of the thermosensitive adhesive layer, and the micropores are filled with expanded graphite particles (31).

6. The flame-retardant, sheathed cable protection pipe according to claim 1, characterized in that: The groove depth of the mechanical interlocking structure (5) matches the height of the protrusion structure (6), forming an interference fit.

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