A fire and heat resistant cable

Abstract

The utility model discloses a kind of fire-resistant high-temperature-resistant cables, including fireproof layer and protective sleeve, the fireproof layer is wrapped and cladded fixed in the protective sleeve outside, and the inside of the protective sleeve is provided with ceramic silicon rubber layer, the inner wall of the ceramic silicon rubber layer is provided with shielding wire net, and the shielding wire net is connected to the outside of heat insulation layer, the inside of the cable core is filled with cable core, the cable core is uniformly provided with multiple core wires inside. Advantageous effect lies in: the utility model is mica tape by spiral winding on the outside of cable skin along cable length, form fireproof layer by mica tape being wound on the outside of protective sleeve, improve the fire-resistant high-temperature-resistant performance of cable under high-temperature environment, meanwhile, evenly clamped and connected multiple steel wires as supporting structure on the outside of protective sleeve, improve the support stability of cable hard rubber sheath skin after being heated and softened.

Description

Technical Field

[0001] This utility model relates to the field of power cables, specifically to a fire-resistant and high-temperature resistant cable. Background Technology

[0002] Cables have many uses, primarily for control installation, equipment connection, and power transmission. They are a common and indispensable part of daily life. Cables are divided into signal cables and power cables. The former are used to transmit signals, such as cable TV fiber optic cables and telephone cables, while the latter are used to transmit electrical energy. Power cables are also required in some high-temperature workshops in factories, and currently, ordinary cables are still used as power transmission equipment in such high-temperature areas.

[0003] The applicant has discovered at least the following technical problems in the prior art: the cables currently in use are protected by a hard rubber shell. This structure is prone to softening and losing its support after long-term use in high-temperature locations, which leads to cable deformation, affects its own structure and the stability of its fixed position. At the same time, the shell poses a safety hazard of ignition damage in high-temperature environments and has poor fire resistance.

[0004] Flame retardants only prevent ignition by open flame. The fire-resistant layer is mostly a single layer of mica tape with low overlap rate and no dense bonding. When impacted by flame, it is easy to form a "thermal channel". Under a 500℃ flame, the heat can penetrate to the core wire in 3-5 minutes, which cannot meet the industrial requirement of "maintaining power supply for 90 minutes of burning at 750℃".

[0005] The copper wire shielding layer has a low braiding density and is loosely connected to the insulation layer, resulting in a shielding effectiveness that drops below 20dB at high temperatures. The insulation layer often uses asbestos, which has a high thermal conductivity. At 500℃, the core wire temperature exceeds the upper limit of the insulation layer's temperature resistance, accelerating aging. Utility Model Content

[0006] The purpose of this utility model is to provide a fire-resistant and high-temperature resistant cable to solve the above problems. A mica tape is wrapped around the outer side of the cable to form a fire-resistant layer, which improves the fire resistance and high-temperature resistance of the cable under high temperature environment. At the same time, multiple steel wires are evenly arranged on the inner side of the cable as a support structure to ensure the support stability after the equipment softens due to heat. See the following description for details.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] This utility model provides a fire-resistant and high-temperature resistant cable, including a fire-resistant layer and a protective sleeve. The fire-resistant layer is wrapped and fixed to the outside of the protective sleeve, and a ceramic silicone rubber layer is provided on the inside of the protective sleeve. A shielding mesh is provided on the inner wall of the ceramic silicone rubber layer, and the shielding mesh is sleeved on the outside of the heat insulation layer. The inside of the heat insulation layer is filled with a cable core, and multiple core wires are evenly arranged inside the cable core.

[0009] The outer side of the protective sleeve is provided with four through-groove-shaped positioning grooves. The length direction of the positioning grooves is parallel to the axis of the protective sleeve, and each of the four positioning grooves is fitted with a supporting steel wire.

[0010] Using the aforementioned fire-resistant and high-temperature resistant cable, when the ambient temperature outside the cable rises, the fire-resistant layer isolates the protective sleeve from the high-temperature environment, preventing the protective sleeve from overheating and being damaged. When the protective sleeve softens due to heat, the supporting steel wire in the positioning groove supports the protective sleeve, thereby preventing the protective sleeve from deforming and bending. The supporting steel wire supports the cable structure, ensuring the fire resistance and structural stability of the cable in high-temperature environments.

[0011] Preferably, the fire-resistant layer is made by spirally winding mica tape along the length of the protective sleeve, and the gap between the fire-resistant layer and the protective sleeve is filled with high-temperature resistant adhesive.

[0012] Preferably, the depth of the positioning groove is the same as the diameter of the supporting steel wire, and the bottom of the positioning groove is an arc-shaped structure that fits the supporting steel wire.

[0013] Preferably, the shielding mesh is made of copper wire, and the shielding mesh is a tubular mesh structure woven from copper wire.

[0014] Preferably, the outer side of the heat insulation layer is provided with a spiral anti-slip texture, and the anti-slip texture is integrally formed with the heat insulation layer, and the shielding mesh is close to the anti-slip texture.

[0015] Preferably, the cable core is made of silicone foam material, and the space between the cable core and the heat insulation layer is filled with resin adhesive.

[0016] Preferably, the outer side of the supporting steel wire is covered with a high-temperature resistant insulating sleeve. The insulating sleeve is made of an insulating material with a temperature resistance not lower than the ambient temperature of the supporting steel wire. The outer side of the insulating sleeve is provided with an anti-slip structure along its length. The inner wall of the positioning groove is provided with a matching structure adapted to the anti-slip structure to limit the axial displacement of the supporting steel wire relative to the positioning groove.

[0017] Preferably, the mica tape of the fire-resistant layer has a composite layer structure, including at least an inner high-temperature resistant mica substrate and an outer reinforcing protective layer.

[0018] Preferably, both ends of the shielding mesh are connected to grounding connectors, and the connection between the grounding connectors and the shielding mesh is covered with high-temperature resistant seals to ensure the sealing and high-temperature resistance of the grounding parts.

[0019] Preferably, the glass fiber yarn of the heat insulation layer adopts a multi-strand twisted structure, and at least two reinforcing ribs are provided inside the heat insulation layer along its circumference. The reinforcing ribs are adapted to the material of the glass fiber yarn and are integrally formed with the heat insulation layer to improve the structural strength and tensile strength of the heat insulation layer.

[0020] The beneficial effects are as follows: This utility model improves the fire resistance and high temperature resistance of the cable in high-temperature environments by spirally winding mica tape around the outside of the cable sheath along the cable length and forming a fire-resistant layer by wrapping the mica tape around the outside of the protective sleeve. At the same time, multiple steel wires are evenly clamped and set on the outside of the protective sleeve as a support structure to improve the support stability of the cable hard rubber sheath after it softens due to heat. Attached Figure Description

[0021] 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.

[0022] Figure 1 This is the main view structural diagram of this utility model;

[0023] Figure 2 This is a structural diagram of the protective sleeve of this utility model;

[0024] Figure 3 This is a structural diagram of the heat insulation layer of this utility model;

[0025] Figure 4 This is a left-side view of the refractory layer of this utility model.

[0026] The annotations in the attached figures are explained as follows:

[0027] 1. Fire-resistant layer; 2. Protective sleeve; 201. Positioning groove; 3. Supporting steel wire; 4. Ceramic silicone rubber layer; 5. Shielding wire mesh; 6. Heat insulation layer; 601. Anti-slip texture; 7. Cable core; 8. Core wire; 9. Inner insulation sheath. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0029] See Figures 1-4As shown, this utility model provides a fire-resistant and high-temperature resistant cable, including a fire-resistant layer 1 and a protective sleeve 2. The fire-resistant layer 1 is wrapped and fixed to the outside of the protective sleeve 2, and a ceramic silicone rubber layer 4 is provided on the inside of the protective sleeve 2. The ceramic silicone rubber layer 4 is ceramicized under high temperature environment and sintered into a porous self-supporting ceramic body, thereby improving the fire resistance of the cable. The ceramic silicone rubber layer 4 is the prior art and will not be described in detail here. A shielding mesh 5 is provided on the inner wall of the ceramic silicone rubber layer 4, and the shielding mesh 5 is sleeved on the outside of the heat insulation layer 6. The shielding mesh 5 is used to increase the electromagnetic shielding performance of the cable. The heat insulation layer 6 is made of asbestos yarn wound and cured to improve the heat insulation effect of the cable. The inside of the heat insulation layer 6 is filled with a cable core 7, and multiple core wires 8 are evenly arranged inside the cable core 7. The outside of the core wires 8 is covered with an inner insulation sheath 9.

[0030] The fire-resistant layer 1 uses phlogopite tape with a thickness of 0.15-0.2mm and a single sheet size of 100-150mm. Compared with ordinary mica tape, phlogopite tape has a temperature resistance of over 1000℃ and stronger anti-peeling properties, which prevents the mica sheets from falling off at high temperatures and causing fire-resistant failure.

[0031] Winding process: Spiral winding along the length of protective sleeve 2, with a winding overlap rate of not less than 50%, that is, the overlap width of two adjacent turns of mica tape is ≥ 1 / 2 of the tape width, ensuring no exposed gaps; the winding tension is controlled at 5-8N to prevent the interlayer from loosening due to insufficient tension or the mica tape from breaking due to excessive tension;

[0032] Fixing method: The gap between the fire-resistant layer 1 and the protective sleeve 2 is filled with high-temperature resistant silicone rubber, such as Dow Corning DC-734, with a temperature range of -60℃ to 315℃. The amount of filling should be just enough to cover the gap without overflowing. The curing time is 24 hours at 25℃. After curing, a dense adhesive layer is formed to prevent the fire-resistant layer from peeling off from the protective sleeve at high temperatures.

[0033] Protective sleeve 2 is made of modified EPDM rubber, with 20%-30% aluminum hydroxide flame retardant and 5%-8% carbon black anti-aging agent added. The upper limit of temperature resistance is 200℃, and the flame retardant rating is UL94V-0, which prevents ignition at high temperatures. The thickness of the protective sleeve is 3-5mm to ensure the strength of the basic structure.

[0034] Positioning groove details: Four through-groove positioning grooves 201 are evenly distributed along the circumference of the protective sleeve 2. The central angle of the adjacent positioning grooves is 90°. The groove width is 0.1-0.2mm larger than the diameter of the supporting steel wire 3 to facilitate the insertion of the steel wire. The groove depth is the same as the diameter of the steel wire to ensure that the steel wire is flush with the outer surface of the protective sleeve after being inserted, without protruding and scratching.

[0035] The inner wall roughness of the positioning groove Ra≤1.6μm to avoid sharp edges scratching the steel wire coating; the two ends of the positioning groove extend to 10-15mm from the cable end to ensure that the steel wire is supported without any breaks along its entire length.

[0036] Four through-groove-shaped positioning grooves 201 are evenly arranged on the outer side of the protective sleeve 2. The length direction of the positioning grooves 201 is parallel to the axis of the protective sleeve 2, and a support steel wire 3 is engaged in each of the four positioning grooves 201. The protective sleeve 2 is supported by the support steel wire 3. In the high temperature environment, the protective sleeve 2 softens, and the support steel wire 3 supports the protective sleeve 2, thereby improving the structural stability of the cable.

[0037] As an optional implementation, the fire-resistant layer 1 is made by spirally winding mica tape along the length of the protective sleeve 2, and the gap between the fire-resistant layer 1 and the protective sleeve 2 is filled with high-temperature resistant adhesive. By setting the fire-resistant layer 1 on the outside of the protective sleeve 2, the fire resistance and high-temperature resistance of the cable are increased. The depth of the positioning groove 201 is the same as the diameter of the supporting steel wire 3, and the bottom of the positioning groove 201 is an arc-shaped structure that fits the supporting steel wire 3, thereby improving the tightness of the connection between the supporting steel wire 3 and the positioning groove 201. The shielding mesh 5 is made of copper wire and is woven into a cylindrical mesh structure. The outer side of the heat insulation layer 6 is provided with a spiral anti-slip texture 601, which is integrally formed with the heat insulation layer 6. The shielding mesh 5 is close to the anti-slip texture 601. The anti-slip texture 601 increases the friction between the shielding mesh 5 and the heat insulation layer 6, thereby preventing the shielding mesh 5 from shifting. The cable core 7 is made of silicone foam material, and the space between the cable core 7 and the heat insulation layer 6 is filled with resin glue, thereby increasing the tightness of the connection between the cable core 7 and the heat insulation layer 6.

[0038] The supporting steel wire 3 is made of 304 stainless steel wire with a diameter of 1.5-2mm, a tensile strength ≥520MPa, and a polyimide insulating coating with a thickness of 0.05-0.1mm. It has a temperature resistance of over 300℃ and a volume resistivity ≥10. 14 Ω·cm, which prevents the steel wire from conducting electricity and causing leakage, and also avoids corrosion at high temperatures;

[0039] Assembly requirements: After the steel wire is inserted into the positioning groove 201, both ends are fixed to the metal connector at the cable end with stainless steel clamps whose inner diameter matches the steel wire to prevent the steel wire from slipping out of the positioning groove when the cable bends; the fit between the steel wire and the positioning groove must be tested for every meter of cable to ensure that there is no looseness and the amount of shaking is ≤0.1mm.

[0040] The ceramic silicone rubber layer 4 is made of addition-type ceramic silicone rubber with a Shore hardness of 60-70A and an elongation at break of ≥300% at room temperature. It contains 15%-20% ceramic powder, such as alumina powder, with a particle size of 5-10μm. It can be sintered into a porous ceramic body with a bulk density of 1.2-1.5 g / cm³ within 30 minutes at 800℃. 3 The compressive strength is ≥10MPa, and it retains a certain toughness after sintering to avoid brittleness.

[0041] Thickness and molding: The ceramic silicone rubber layer 4 is 2-3mm thick and is wrapped inside the protective sleeve 2 using an extrusion molding process. The bonding strength between the layer and the protective sleeve is ≥1.5MPa and is tested by peel test to ensure that it does not separate from the protective sleeve at high temperature.

[0042] The shielding wire mesh 5 uses T2 copper wire with a diameter of 0.1-0.15mm and a conductivity of ≥98% IACS. It is woven into a cylindrical mesh with a weaving density of ≥90%, that is, the mesh area ratio is ≤10%. The shielding effectiveness is ≥60dB in the frequency range of 100MHz-1 GHz, effectively blocking external electromagnetic interference.

[0043] Assembly details: If the grounding terminals at both ends of the shielding wire mesh 5 and the cable end are designed with welding joints of 5-8mm in length and welding strength ≥5N, grounding shielding can be achieved; when the wire mesh is sleeved on the outside of the heat insulation layer 6, a small amount of high-temperature resistant silicone grease with a temperature resistance of 300℃ or higher should be applied to the inside of the wire mesh first, which will reduce assembly resistance and enhance the fit with the anti-slip texture.

[0044] The threaded anti-slip texture 601 has a triangular tooth height of 0.5-0.8mm and a pitch of 5-8mm. It is integrally formed with the heat insulation layer 6 by molding. The surface roughness of the anti-slip texture Ra=1.6-3.2μm increases the friction with the shielding mesh. Tests show that under a 10N axial tensile force, the relative displacement between the shielding mesh and the heat insulation layer is ≤0.5mm, effectively preventing the mesh from shifting.

[0045] Cable core material: High-temperature resistant silicone foam material with a density of 0.4-0.6 g / cm³. 3 With a closed-cell rate of ≥90% and a temperature resistance of over 200℃, it has excellent buffering and heat insulation properties. When filling the inner side of the heat insulation layer 6, a pressure filling process of 0.2-0.3MPa is adopted to ensure that there are no gaps in the cable core and to avoid the core wire from shaking.

[0046] The core wire 8 is made of multi-strand soft copper conductor material T2, with 19-37 strands and a single strand diameter of 0.15-0.2mm. The conductor's long-term allowable operating temperature is 150℃. The inner insulation sheath 9 is made of cross-linked polyethylene XLPE, with a thickness of 0.8-1mm, a temperature resistance of 125℃, and a dielectric loss tangent of ≤0.005@70℃. It is wrapped around the outside of the core wire through an extrusion process, with an insulation thickness deviation of ≤±0.1mm to ensure insulation uniformity. The arrangement of the core wires 8 inside the cable core 7 adopts the method of "1 core in the center + evenly distributed on the periphery". For example, when there are 7 cores in total, there is 1 core in the center and 6 cores on the periphery. The spacing between adjacent core wires is ≥1mm to avoid short circuits caused by insulation sheath wear.

[0047] The space between the cable core 7 and the heat insulation layer 6 is filled with high-temperature resistant epoxy resin adhesive, such as model E-51, with 5%-10% added silica powder for modification. It has a temperature resistance of over 150℃ and a shear strength ≥12MPa after curing. After filling, it is cured at 80℃ for 2 hours to ensure that the cable core and the heat insulation layer are tightly bonded without relative displacement.

[0048] Fire resistance performance: According to GB / T19216.21-2003 "Line integrity of cables or optical fibers under flame conditions - Part 21: Test procedures and requirements for cables with rated voltage of 0.6 / 1.0kV and below", after burning in a flame at 750℃±50℃ for 90 minutes, the cable can still maintain a voltage of 0.75kV and a current of 10A without breakdown or short circuit.

[0049] High temperature resistance: After being placed in a constant temperature environment of 400℃ for 1000h, the protective sleeve 2 shows no obvious softening or hardness change ≤10 Shore A, the supporting steel wire 3 shows no rust, and the insulation resistance of the core wire 8 is ≥100MΩ at 25℃ and tested with a 500V megohmmeter.

[0050] Mechanical performance: Under normal temperature, after a bending test with a bending radius of 15 times the outer diameter of the cable and 100 bending cycles, the supporting steel wire 3 showed no breakage, the shielding mesh 5 showed no damage, and the core wire 8 showed normal continuity.

[0051] Electromagnetic shielding performance: At a frequency of 1 GHz, the shielding effectiveness is ≥65 dB, which meets the protection requirements for electromagnetic interference in industrial environments.

[0052] The outer side of the supporting steel wire 3 is covered with a high-temperature resistant insulating sleeve. The insulating sleeve is made of insulating material with a temperature resistance not lower than the ambient temperature of the supporting steel wire 3. The outer side of the insulating sleeve is provided with an anti-slip structure along its length. The inner wall of the positioning groove 201 is provided with a matching structure adapted to the anti-slip structure to limit the axial displacement of the supporting steel wire 3 relative to the positioning groove 201.

[0053] The mica tape of the fire-resistant layer 1 has a composite layer structure, including at least an inner high-temperature resistant mica substrate and an outer reinforcing protective layer.

[0054] Both ends of the shielding wire mesh 5 are connected to grounding connectors, and the connection between the grounding connectors and the shielding wire mesh 5 is covered with high-temperature resistant sealant to ensure the sealing and high-temperature resistance of the grounding part.

[0055] The glass fiber yarn of the heat insulation layer 6 adopts a multi-strand twisted structure, and at least two reinforcing ribs are provided inside the heat insulation layer 6 along its circumference. The reinforcing ribs are adapted to the glass fiber yarn material and integrally formed with the heat insulation layer 6 to improve the structural strength and tensile strength of the heat insulation layer 6.

[0056] With the above structure, when the ambient temperature outside the cable rises, the fire-resistant layer 1 isolates the protective sleeve 2 from the high-temperature environment to prevent the protective sleeve 2 from overheating and being damaged. When the protective sleeve 2 softens due to heat, the support steel wire 3 in the positioning groove 201 supports the protective sleeve 2, thereby preventing the protective sleeve 2 from deforming and bending. The support steel wire 3 supports the cable structure, ensuring the fire resistance and structural stability of the cable in the high-temperature environment.

[0057] By spirally winding mica tape along the cable length on the outer side of the cable sheath, a fire-resistant layer 1 is formed by the mica tape wrapped around the outer side of the protective sleeve 2, which improves the fire resistance and high temperature resistance of the cable in high-temperature environments. At the same time, multiple steel wires are evenly clamped and set on the outer side of the protective sleeve 2 as a support structure to improve the support stability of the cable after the hard rubber sheath softens due to heat.

[0058] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the protection scope of the claims.

Claims

1. A fire-resistant and high-temperature resistant cable, characterized in that: It includes a fire-resistant layer (1) and a protective sleeve (2). The fire-resistant layer (1) is wrapped around and fixed to the outside of the protective sleeve (2). A ceramic silicone rubber layer (4) is provided on the inside of the protective sleeve (2). A shielding wire mesh (5) is provided on the inner wall of the ceramic silicone rubber layer (4). The shielding wire mesh (5) is sleeved on the outside of the heat insulation layer (6). The heat insulation layer (6) is filled with a cable core (7). Multiple core wires (8) are evenly arranged inside the cable core (7). The protective sleeve (2) has four through-groove-shaped positioning grooves (201) evenly arranged on the outside. The length direction of the positioning groove (201) is parallel to the axis of the protective sleeve (2), and a support steel wire (3) is engaged in each of the four positioning grooves (201).

2. The fire-resistant and high-temperature resistant cable according to claim 1, characterized in that: The fire-resistant layer (1) is made by spirally winding mica tape along the length of the protective sleeve (2), and the gap between the fire-resistant layer (1) and the protective sleeve (2) is filled with high-temperature resistant adhesive.

3. The fire-resistant and high-temperature resistant cable according to claim 2, characterized in that: The depth of the positioning groove (201) is the same as the diameter of the supporting steel wire (3), and the bottom of the positioning groove (201) is an arc-shaped structure that fits the supporting steel wire (3).

4. The fire-resistant and high-temperature resistant cable according to claim 1, characterized in that: The shielding mesh (5) is made of copper wire, and the shielding mesh (5) is a tubular mesh structure woven from copper wire.

5. The fire-resistant and high-temperature resistant cable according to claim 4, characterized in that: The heat insulation layer (6) has a spiral anti-slip texture (601) on its outer side, and the anti-slip texture (601) is integrally formed with the heat insulation layer (6), and the shielding mesh (5) is close to the anti-slip texture (601).

6. The fire-resistant and high-temperature resistant cable according to claim 1, characterized in that: The cable core (7) is made of silicone foam material, and the space between the cable core (7) and the heat insulation layer (6) is filled with resin glue.

7. The fire-resistant and high-temperature resistant cable according to claim 5, characterized in that: The outer side of the supporting steel wire (3) is covered with a high-temperature resistant insulating sleeve. The insulating sleeve is made of insulating material with a temperature resistance not lower than that of the supporting steel wire (3) in use environment temperature. The outer side of the insulating sleeve is provided with an anti-slip structure along its length direction. The inner wall of the positioning groove (201) is provided with a matching structure adapted to the anti-slip structure to limit the axial displacement of the supporting steel wire (3) relative to the positioning groove (201).

8. The fire-resistant and high-temperature resistant cable according to claim 7, characterized in that: The mica tape of the fire-resistant layer (1) has a composite layer structure, including at least an inner high-temperature resistant mica substrate and an outer reinforcing protective layer.

9. The fire-resistant and high-temperature resistant cable according to claim 8, characterized in that: Both ends of the shielding wire mesh (5) are connected to grounding connectors, and the connection between the grounding connectors and the shielding wire mesh (5) is covered with high-temperature resistant sealant to ensure the sealing and high-temperature resistance of the grounding part.

10. The fire-resistant and high-temperature resistant cable according to claim 9, characterized in that: The glass fiber yarn of the heat insulation layer (6) adopts a multi-strand twisted structure, and at least two reinforcing ribs are provided inside the heat insulation layer (6) along its circumference. The reinforcing ribs are adapted to the glass fiber yarn material and integrally formed with the heat insulation layer (6) to improve the structural strength and tensile strength of the heat insulation layer (6).

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