Preparation method of armored fire-fighting sensing line

Abstract

The invention discloses a preparation method of an armored fire-fighting sensing line. The method comprises the following steps: 1, forming a graphene oxide-based sensitive layer; 2, preparing an insulating layer or a self-repairable insulating layer; and step 3, spiral armoring layered protection is carried out to form an integral protection structure. Through material innovation, structure optimization and process upgrading, the defects of corrosion, high-temperature failure, mechanical fragility, irreparability and the like of a traditional fire-fighting sensing line are overcome, high sensitivity, quick response, long-acting durability and environmental adaptability are achieved, and the safety and economical efficiency of a fire-fighting system are remarkably improved. The fire extinguishing system is suitable for the fields such as metallurgical workshops, ship engine cabins, chemical plants, offshore platforms, subway tunnels and pipe galleries with strict requirements for the fire extinguishing system.

Description

Technical Field

[0001] The present invention relates to the technical field of electric wires and cables, and in particular to a method for preparing an armored fire-fighting sensor wire. Background Art

[0002] Fire communication lines are critical circuits for transmitting commands and data in fire alarm and linkage control systems. They facilitate bidirectional information exchange between the fire control host and terminal equipment (such as detectors, fire telephones, and smoke exhaust fans). Their core functions include transmitting fire alarm signals, fault conditions, and equipment control commands, ensuring rapid information transfer in the event of a fire. The conductors of the fire sensor lines are filled with a thermosensitive insulating material (such as a low-melting-point copolymer). When the temperature exceeds a threshold (typically adjustable between 68°C and 160°C), the insulating material's resistivity drops sharply, triggering a short-circuit signal between the wires. The microcontroller then determines the fire's location based on the rate of change in impedance, with an accuracy of ±0.5m.

[0003] Currently, fire sensor cables face the following technical bottlenecks: Traditional metal armor (such as 304 stainless steel) is susceptible to corrosion in acidic and alkaline environments, resulting in signal transmission failure. Ordinary polyethylene sheaths easily melt at high temperatures and fail to meet the 950°C / 180-minute fire resistance requirements of GB 16280-2025. Existing sensor cables generally have a tensile strength of less than 200 MPa, making them susceptible to crush damage in complex environments like pipe corridors. Furthermore, existing fire sensor cables are difficult to reuse. Summary of the Invention

[0004] Purpose of the invention: In view of the shortcomings of the existing technology, the present invention provides a method for preparing an armored fire sensor wire.

[0005] Technical solution: The present invention provides a method for preparing an armored fire sensor wire. Technical solution 1 includes the following steps:

[0006] Step 1: The metal core wire is passed through a plasma cleaner to remove surface oxides. Graphene oxide and carbon nanotubes are then dispersed in an NMP solvent at a mass ratio of 3-4:1. A polyvinylidene fluoride binder (PVDF) is added and ultrasonically treated for 2-3 hours to form a homogeneous slurry. This slurry is then applied to the surface of a silver-plated copper core wire using a micro-gravure coating technique. The coating thickness is controlled to 50±5μm, and the sensitive layer is formed after vacuum drying at 80±5°C. The resistance change rate reaches 0.85% / °C within the temperature range of 50-300°C (compared to <0.3% / °C for conventional products), and the response time is shortened to 5.3 seconds.

[0007] Step 2: Wrap the glass fiber braided layer on the sensitive layer, and then use a twin-screw extruder to wrap the flame-retardant polyurethane particles on the glass fiber braided layer at a temperature range of 185-210° C. to obtain an insulating layer with a thickness of 0.5±1 mm.

[0008] Step 3: Use a spiral winding process to armor the metal belt outside the insulation layer, mix fluororubber and silicon carbide powder and then apply it with a coating thickness of 0.5±1mm, and vulcanize it at 160-180℃ and 15-16MPa for 20-40min to form an overall protective structure.

[0009] As a further improvement, the present invention also provides a second technical solution, comprising the following steps:

[0010] Step 1: The metal core wire is passed through a plasma cleaner to remove surface oxides. A three-dimensional graphene / carbon nanotube composite layer is then grown on the surface via chemical vapor deposition. The deposition temperature is controlled between 750-800°C and the deposition time is 60-80 minutes, forming a sensitive layer with a thickness of 20±1μm. The resistance gradient reaches 1.2% / °C within the temperature range of 50-300°C, with a response time of less than 3 seconds. This improvement significantly enhances sensitivity, and the 20±1μm thickness shortens the heat conduction path, further reducing response time.

[0011] Step 2: Wrap the glass fiber braided layer on the sensitive layer, and then use a twin-screw extruder to wrap the flame-retardant polyurethane particles on the glass fiber braided layer at a temperature range of 185-210° C. to obtain an insulating layer with a thickness of 0.5±1 mm.

[0012] Step 3: Use a spiral winding process to armor the metal belt outside the insulation layer, mix fluororubber and silicon carbide powder and then apply it with a coating thickness of 0.5±1mm, and vulcanize it at 160-180℃ and 15-16MPa for 20-40min to form an overall protective structure.

[0013] Specifically, the metal core wire is a copper core wire or a silver-plated copper core wire with a diameter of 1.5±0.1 mm. For the present invention, the silver-plated copper core wire is preferred.

[0014] Specifically, the metal strip is a 304 stainless steel strip, a NiTiNol shape memory alloy strip, or a galvanized high carbon steel strip. For the present invention, the NiTiNol shape memory alloy strip is preferred.

[0015] Specifically, the fluororubber is mixed with silicon carbide powder, and the volume proportion of the silicon carbide powder is 18-22%.

[0016] As a further improvement, the present invention also provides a third technical solution, comprising the following steps:

[0017] Step 1: The metal core wire is treated with a plasma cleaner to remove surface oxides; then, graphene oxide and carbon nanotubes are dispersed in an NMP solvent at a mass ratio of 3 to 4:1, 5 to 6 wt% polyvinylidene fluoride adhesive is added, and ultrasonic treatment is performed for 2 to 3 hours to form a homogeneous slurry. The slurry is coated on the surface of the silver-plated copper core wire using a micro-gravure coating technique, and the coating thickness is controlled to be 50±5 μm. After vacuum drying at 80±5°C, a sensitive layer is formed.

[0018] Step 2: Wrap the glass fiber woven layer on the sensitive layer, then mix the DCPD monomer microcapsules with flame-retardant polyurethane particles, and use a double-layer co-extrusion process to wrap the glass fiber woven layer with a coating thickness of 0.5±0.1mm to obtain a self-healing insulation layer. The microcapsule distribution density is >200 / mm2. The microcapsules contain a silicon-based repair agent, which can achieve self-repair within 24 hours when the insulation layer cracks. Microcapsule triggering mechanism: When cracks appear in the insulation layer, stress concentration causes the DCPD microcapsules to rupture, releasing the silicon-based repair agent (viscosity 200-300cP), which undergoes a condensation reaction with the polyurethane matrix (Si-OH+HO-Si→Si-O-Si+H2O) to form a cross-linked network, thereby repairing the insulation layer.

[0019] Step 3: Use a spiral winding process to armor the metal tape outside the insulation layer with a coverage rate of ≥85%, mix fluororubber and silicon carbide powder and apply it with a coating thickness of 0.5±1mm, and vulcanize it at 160-180℃ and 15-16MPa for 20-40min to form an overall protective structure.

[0020] As a further improvement, the present invention also provides a fourth technical solution, comprising the following steps:

[0021] Step 1: The metal core wire is treated with a plasma cleaner to remove surface oxides; a three-dimensional graphene / carbon nanotube composite layer is grown on its surface by chemical vapor deposition, with the deposition temperature controlled at 750-800°C and the deposition time at 60-80 minutes to form a sensitive layer with a thickness of 20±1 μm.

[0022] Step 2: Wrap the glass fiber braided layer on the sensitive layer, then mix the DCPD monomer microcapsules with flame-retardant polyurethane particles, and use a double-layer co-extrusion process to coat the glass fiber braided layer with a coating thickness of 0.5±0.1mm to obtain a self-repairing insulation layer. The microcapsule distribution density is >200 / mm 2 The microcapsules contain a silicon-based repair agent that can self-repair within 24 hours if the insulation layer cracks.

[0023] Step 3: Use a spiral winding process to armor the metal tape outside the insulation layer with a coverage rate of ≥85%, mix fluororubber and silicon carbide powder and apply it with a coating thickness of 0.5±1mm, and vulcanize it at 160-180℃ and 15-16MPa for 20-40min to form an overall protective structure.

[0024] Specifically, the DCPD monomer microcapsules store dicyclopentadiene (DCPD) monomer in polyurea formaldehyde (PUF) microcapsules with a size of 150±20 μm. Specifically, the DCPD monomer microcapsules have a particle size of 150±20 μm. Specifically, the DCPD monomer microcapsules account for 15 wt% of the mixture.

[0025] Beneficial effects: The present invention significantly improves the temperature coefficient of resistance through the graphene-based composite sensitive layer, accurately controls the thickness of the sensitive layer, optimizes the heat conduction path, shortens the response time, and realizes rapid fire positioning.

[0026] The flame-retardant polyurethane insulation layer can withstand temperatures of 950°C for 180 minutes, meeting the fire resistance requirements of GB 16280-2025. A self-healing layer of DCPD microcapsules, through the polycondensation reaction of a silicone-based repair agent, automatically repairs cracks in the insulation layer within 24 hours, extending service life and reducing maintenance costs.

[0027] The present invention uses NiTiNol shape memory alloy, which has a tensile strength exceeding 200 MPa and is adaptable to complex working conditions. The fluororubber / silicon carbide mixed outer sheath (cured by a vulcanization process) is both acid and alkali resistant, wear-resistant, and fire-resistant, solving the corrosion problem of traditional stainless steel armor.

[0028] The present invention is applicable to fields with strict requirements on fire protection systems, such as metallurgical workshops, ship engine rooms, chemical plants, offshore platforms, subway tunnels, and pipe galleries. DETAILED DESCRIPTION

[0029] The following embodiments describe the present invention in detail, but the protection scope of the present invention is not limited to the embodiments.

[0030] Example 1

[0031] Step 1, use The silver-plated copper core wire is first treated with a plasma cleaning machine (power 300W, argon atmosphere) to remove surface oxides.

[0032] Graphene oxide and carbon nanotubes were dispersed in NMP solvent at a mass ratio of 3:1. 5 wt% polyvinylidene fluoride (PVDF) binder was added and ultrasonicated for 2 hours to form a homogeneous slurry. The slurry was then applied to the surfaces of two silver-plated copper core wires using a micro-gravure coating technique. The coating thickness was controlled to 50 ± 5 μm, and the sensitive layer was formed after vacuum drying at 80°C.

[0033] The resistance change rate in the temperature range of 50-300°C is 0.85% / °C, and the response time is shortened to 5.3 seconds (GB / T19666-2019 standard test)

[0034] Step 2: Wrap the glass fiber braided layer on the sensitive layer, and then use a twin-screw extruder (temperature range 185-210° C.) to wrap the flame-retardant polyurethane particles on the glass fiber braided layer with a thickness of 0.5 mm to obtain an insulating layer.

[0035] Step 3: Use spiral winding process to armor 304 stainless steel strip outside the insulation layer, with a coverage rate of ≥85%.

[0036] Fluororubber (FKM2603) and silicon carbide powder (20 vol%) were mixed and coated with a coating thickness of 0.5 mm and vulcanized at 160° C. and 15 MPa for 20 minutes to form an integral protective structure.

[0037] The test results of Example 1 are shown in the following table:

[0038]

[0039] Example 2

[0040] The basic steps of Example 2 are substantially the same as those of Example 1, except that, in step 3, a NiTiNol shape memory alloy strip is armored outside the insulating layer.

[0041] Example 3

[0042] The basic steps of Example 3 are substantially the same as those of Example 1, except that, in Step 3, a galvanized high-carbon steel strip is armored outside the insulating layer.

[0043] Example 4

[0044] The basic steps of Example 4 are substantially the same as those of Example 1, except that in step 3, the coating material is silicone rubber.

[0045] Example 5

[0046] The basic steps of Example 5 are substantially the same as those of Example 1, except that in step 3, the coating material is fluororubber.

[0047] Example 6

[0048] Step 1, use The silver-plated copper core wire is first treated with a plasma cleaning machine (power 300W, argon atmosphere) to remove surface oxides.

[0049] A three-dimensional graphene / carbon nanotube composite layer was grown on the surface of two silver-plated copper core wires by chemical vapor deposition. The deposition temperature was controlled at 750°C and the time was 60 minutes to form a sensitive layer with a thickness of 20 μm.

[0050] The resistance change rate in the temperature range of 50-300℃ is 1.2% / ℃, and the response time is shortened to <3 seconds (GB / T19666-2019 standard test)

[0051] Step 2: Wrap the glass fiber braided layer on the sensitive layer, and then use a twin-screw extruder (temperature range 185-210° C.) to wrap the flame-retardant polyurethane particles on the glass fiber braided layer with a thickness of 0.5 mm to obtain an insulating layer.

[0052] Step 3: Use spiral winding process to armor 304 stainless steel strip outside the insulation layer, with a coverage rate of ≥85%.

[0053] Fluororubber (FKM2603) and silicon carbide powder (20 vol%) were mixed and coated with a coating thickness of 0.5 mm and vulcanized at 160° C. and 15 MPa for 20 minutes to form an integral protective structure.

[0054] Example 7

[0055] Step 1, use The silver-plated copper core wire is first treated with a plasma cleaning machine (power 300W, argon atmosphere) to remove surface oxides.

[0056] Graphene oxide and carbon nanotubes were dispersed in NMP solvent at a mass ratio of 3:1. 5 wt% polyvinylidene fluoride (PVDF) binder was added and ultrasonicated for 2 hours to form a homogeneous slurry. The slurry was then applied to the surfaces of two silver-plated copper core wires using a micro-gravure coating technique. The coating thickness was controlled to 50 ± 5 μm, and the sensitive layer was formed after vacuum drying at 80°C.

[0057] Step 2: A glass fiber braid is coated over the sensitive layer. DCPD monomer microcapsules (particle size 150 ± 20 μm) and flame-retardant polyurethane particles (UL94 V-0) are mixed at a ratio of 15 wt%. The layer is then coated over the glass fiber braid using a double-layer co-extrusion process to a thickness of 0.5 mm, resulting in a self-healing insulation layer. The microcapsules have a distribution density of >200 per mm². The microcapsules contain a silicon-based repair agent, which enables self-healing within 24 hours if the insulation layer cracks.

[0058] After artificially creating a 0.2mm deep scratch, the insulation resistance recovers to 91% of the initial value within 2 hours at 25°C (IEC 60331-1 standard test).

[0059] Step 3: Use spiral winding process to armor 304 stainless steel strip outside the insulation layer, with a coverage rate of ≥85%.

[0060] Fluororubber (FKM2603) and silicon carbide powder (20 vol%) were mixed and coated with a coating thickness of 0.5 mm and vulcanized at 160° C. and 15 MPa for 20 minutes to form an integral protective structure.

[0061] Example 8

[0062] The basic steps of Example 8 are substantially the same as those of Example 1, except that, in step 3, a NiTiNol shape memory alloy strip is armored outside the insulating layer.

[0063] Example 9

[0064] The basic steps of Example 9 are substantially the same as those of Example 1, except that, in step 3, a galvanized high-carbon steel strip is armored outside the insulating layer.

[0065] Example 10

[0066] The basic steps of Example 10 are substantially the same as those of Example 1, except that in step 3, the coating material is silicone rubber.

[0067] Example 11

[0068] The basic steps of Example 11 are substantially the same as those of Example 1, except that in step 3, the coating material is fluororubber.

[0069] Example 12

[0070] Step 1, use The silver-plated copper core wire is first treated with a plasma cleaning machine (power 300W, argon atmosphere) to remove surface oxides.

[0071] A three-dimensional graphene / carbon nanotube composite layer was grown on the surface of two silver-plated copper core wires by chemical vapor deposition. The deposition temperature was controlled at 750°C and the time was 60 minutes to form a sensitive layer with a thickness of 20 μm.

[0072] Step 2: Wrap the glass fiber braided layer on the sensitive layer, then mix DCPD monomer microcapsules (particle size 150±20μm) and flame retardant polyurethane particles (UL94 V-0 grade) at a ratio of 15wt%, and use a double-layer co-extrusion process to coat the glass fiber braided layer with a coating thickness of 0.5mm to obtain a self-healing insulation layer. The microcapsule distribution density is >200 / mm 2 The microcapsules contain a silicon-based repair agent that can self-repair within 24 hours when the insulation layer cracks.

[0073] Step 3: Use spiral winding process to armor 304 stainless steel strip outside the insulation layer, with a coverage rate of ≥85%.

[0074] Fluororubber (FKM2603) and silicon carbide powder (20 vol%) were mixed and coated with a coating thickness of 0.5 mm and vulcanized at 160° C. and 15 MPa for 20 minutes to form an integral protective structure.

[0075] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application.

Claims

1. A method for preparing an armored fire sensor wire, characterized in that: The steps include: Step 1: The metal core wire is treated with a plasma cleaner to remove surface oxides; then, graphene oxide and carbon nanotubes are dispersed in an NMP solvent at a mass ratio of 3 to 4:1, 5 to 6 wt% polyvinylidene fluoride binder is added, and ultrasonic treatment is performed for 2 to 3 hours to form a homogeneous slurry. The slurry is coated on the surface of the silver-plated copper core wire using a micro-gravure coating technique. The coating thickness is controlled to 50 ± 5 μm, and the sensitive layer is formed after vacuum drying at 80 ± 5 ° C. Step 2: Wrap the glass fiber braided layer on the sensitive layer, and then use a twin-screw extruder to coat the flame-retardant polyurethane particles on the glass fiber braided layer at a temperature range of 185-210°C to obtain an insulating layer with a thickness of 0.5±1mm; Step 3: Use a spiral winding process to armor the metal tape outside the insulation layer with a coverage rate of ≥85%, mix fluororubber and silicon carbide powder and apply it with a coating thickness of 0.5±1mm, and vulcanize it at 160-180℃ and 15-16MPa for 20-40min to form an overall protective structure.

2. The method for preparing the armored fire sensor wire according to claim 1, characterized in that: The steps include: Step 1: The metal core wire is treated with a plasma cleaner to remove surface oxides; a three-dimensional graphene / carbon nanotube composite layer is grown on the surface by chemical vapor deposition, with the deposition temperature controlled at 750-800°C for 60-80 minutes to form a sensitive layer with a thickness of 20±1 μm. Step 2: Wrap the glass fiber braided layer on the sensitive layer, and then use a twin-screw extruder to coat the flame-retardant polyurethane particles on the glass fiber braided layer at a temperature range of 185-210°C to obtain an insulating layer with a thickness of 0.5±1mm; Step 3: Use a spiral winding process to wrap a metal tape around the insulating layer with a coverage rate of ≥85%, mix fluororubber and silicon carbide powder and apply the mixture with a coating thickness of 0.5±1mm, and vulcanize at 160-180°C and 15-16MPa for 20-40min to form an overall protective structure.

3. The method for preparing the armored fire sensor wire according to claim 1, characterized in that: The steps include: Step 1: The metal core wire is treated with a plasma cleaner to remove surface oxides; then, graphene oxide and carbon nanotubes are dispersed in an NMP solvent at a mass ratio of 3 to 4:1, 5 to 6 wt% polyvinylidene fluoride binder is added, and ultrasonic treatment is performed for 2 to 3 hours to form a homogeneous slurry. The slurry is coated on the surface of the silver-plated copper core wire using a micro-gravure coating technique. The coating thickness is controlled to 50 ± 5 μm, and the sensitive layer is formed after vacuum drying at 80 ± 5 ° C. Step 2: Wrap the glass fiber braided layer on the sensitive layer, then mix the DCPD monomer microcapsules with flame-retardant polyurethane particles, and use a double-layer co-extrusion process to coat the glass fiber braided layer with a coating thickness of 0.5±0.1mm to obtain a self-repairing insulation layer; Step 3: Use a spiral winding process to armor the metal tape outside the insulation layer with a coverage rate of ≥85%, mix fluororubber and silicon carbide powder and apply it with a coating thickness of 0.5±1mm, and vulcanize it at 160-180℃ and 15-16MPa for 20-40min to form an overall protective structure.

4. The method for preparing the armored fire sensor wire according to claim 1, characterized in that: The steps include: Step 1: The metal core wire is treated with a plasma cleaner to remove surface oxides; a three-dimensional graphene / carbon nanotube composite layer is grown on the surface by chemical vapor deposition, with the deposition temperature controlled at 750-800°C for 60-80 minutes to form a sensitive layer with a thickness of 20±1 μm. Step 2: Wrap the glass fiber braided layer on the sensitive layer, then mix the DCPD monomer microcapsules with flame-retardant polyurethane particles, and use a double-layer co-extrusion process to coat the glass fiber braided layer with an outer layer thickness of 0.5±0.1mm to obtain a self-repairing insulation layer; Step 3: Use a spiral winding process to armor the metal tape outside the insulation layer with a coverage rate of ≥85%, mix fluororubber and silicon carbide powder and apply it with a coating thickness of 0.5±1mm, and vulcanize it at 160-180℃ and 15-16MPa for 20-40min to form an overall protective structure.

5. The method for preparing the armored fire sensor wire according to claims 1-4, characterized in that: The metal core wire is a copper core wire or a silver-plated copper core wire with a diameter of 1.5±0.1mm.

6. The method for preparing the armored fire sensor wire according to claims 1-4, characterized in that: The metal strip is a 304 stainless steel strip, a NiTiNol shape memory alloy strip, or a galvanized high carbon steel strip.

7. The method for preparing the armored fire sensor wire according to claims 1-4, characterized in that: The fluororubber is mixed with silicon carbide powder, and the volume proportion of the silicon carbide powder is 18-22%.

8. The method for preparing the armored fire sensor wire according to claim 3-4, characterized in that: The DCPD monomer microcapsules are dicyclopentadiene monomers stored in polyurea formaldehyde microcapsules.

9. The method for preparing the armored fire sensor wire according to claim 3-4, characterized in that: The DCPD monomer microcapsules have a particle size of 150±20 μm.

10. The method for preparing the armored fire sensor wire according to claim 3-4, characterized in that: The mass of the DCPD monomer microcapsules accounts for 15wt% of the mixture.

Images