A core wire manufacturing method for improving the electric conductivity of an electric heating core wire of an oil pipe

Abstract

The application belongs to the technical field of petroleum pipe material electric heating equipment, and particularly relates to a core wire manufacturing method for improving the electric conduction performance of a petroleum pipe material electric heating core wire. The core wire manufacturing method for improving the electric conduction performance of the petroleum pipe material electric heating core wire comprises the following steps: preparing raw materials, mold forming, manufacturing the formed alloy ingot into a wire shape, preparing an outer insulation layer of the wire, manufacturing a second insulation layer of the wire, and mixing and coating heat reflecting paint and heat resisting paint onto the surface of the wire. The application improves the electric conduction performance of the core wire by adding a small amount of silver through suitable proportioning, so as to obtain sufficient electric conductivity. The application improves the durability and service life of the core wire by adding nickel alloy and silver, so as to improve the electric conduction performance of the core wire under high temperature. The application resists the erosion of acidic environment, high temperature gas and corrosive salt solution by adding nickel alloy, so as to effectively prevent the performance of the core wire from being reduced due to high temperature aging.

Description

Technical Field

[0001] This invention belongs to the technical field of electric heating equipment for oil pipes, and specifically relates to a method for manufacturing a core wire that improves the conductivity of the core wire in an electric heating system for oil pipes. Background Technology

[0002] An electric heating device for oil pipelines is a device used to heat oil pipelines. It typically uses electricity as its energy source, converting electrical energy into heat energy and transferring it to the pipeline to maintain the flow of oil during transportation. This device usually consists of an electric heater, a control system, and maintenance equipment. The electric heater is the key component; it generates heat energy by energizing the pipeline and transfers heat to the oil pipeline through direct contact or radiation.

[0003] For example, the pipeline oil heating device disclosed in Chinese Patent Publication No. CN2908975Y includes a heating element made of metal material for heating oil installed inside the heating pipeline via supporting components. An induction coil for connecting to an AC power source is wound around the outer surface of the heating pipeline. Supporting ribs are also provided between the supporting components to stabilize them. The induction coil is connected to the AC power source via a temperature controller. This device has a simple structure, can heat oil transported from inside the oil pipeline, has high electrothermal efficiency, low heat loss, eliminates the need for insulation materials to prevent heat loss between the oil to be heated and the heat source, requires minimal maintenance, and is low in cost.

[0004] The core wire of an electric heating device for oil pipes refers to the conductor used to transmit electrical energy. In the electric heating device, the core wire plays the role of transmitting electrical energy to the heater. Typically, the core wire of an electric heating device for oil pipes uses high-temperature resistance wire as the conductor material. High-temperature resistance wire has high temperature resistance and can operate normally in high-temperature environments. However, the heating of the oil pipe itself is also achieved through resistance heating. The heated oil pipe will accumulate heat, which in turn affects the core wire. At high temperatures, the conductivity of the core wire will continuously decrease. Currently, the only solution is to continue to improve the conductivity of the core wire; there is no better solution. Summary of the Invention

[0005] This invention provides a method for manufacturing core wires to improve the conductivity of electric heating core wires in oil pipes. The purpose is to provide a method that can improve the conductivity of the core wires at high temperatures and effectively prevent the performance degradation of the conductors caused by high-temperature aging.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for manufacturing a core wire to improve the conductivity of an electric heating core wire for oil pipes includes the following steps: Step 1: Prepare raw materials Weigh out the copper, aluminum, nickel alloy, and silver materials according to the specified proportions; Step 2: Molding The copper, aluminum, nickel alloy and silver materials weighed according to the ratio are melted and then poured into the mold to form the shape; Step 3: Form the alloy ingot formed in Step 2 into a wire shape; Step 4: Prepare the outer insulation layer of the wire; Step 5: Create a second layer of insulation for the wire; Step 6: Mix the heat-reflective coating and the heat-resistant coating and apply them to the surface of the wire to complete the preparation.

[0007] The proportions of copper, aluminum, nickel alloy and silver in the raw materials prepared in step one are: copper 50-60%, aluminum 30-40%, nickel alloy 9.0-10% and silver 0.3-0.6%.

[0008] The specific process of step two, molding, involves placing the copper selected in step one into a container, heating it to 1100-1200℃ to melt it, then adding aluminum and silver selected in proportion, and continuing to heat it to 1300-1500℃ to add nickel alloy, so that the copper, aluminum, nickel alloy and silver are liquefied, and stirred until uniform, and then placed into a mold to cool and form.

[0009] The equipment for melting copper, aluminum, nickel alloys and silver is an electric arc furnace; the electric arc furnace has a power of 20MW-50MW, and the total weight of copper, aluminum, nickel alloys and silver heated in a single electric arc furnace is 8t-10t; wherein, the copper, aluminum, nickel alloys and silver liquids are mixed using a stirring rod; the stirring rod is one or more of the following: Ti-6Al-4V stirring rod, cobalt-based high-temperature alloy stirring rod, alumina ceramic stirring rod and silicon nitride ceramic.

[0010] The method for processing alloy ingots into wire in step three includes the following steps: The first step is to produce continuous wire from alloy ingots by continuous casting or extrusion. Step 2: Cooling and Demagnetizing After continuous casting or extrusion, the wire is cooled and demagnetized. Step 3: Bending and Stretching Cooled wires are shaped and deformed through bending and stretching processes to obtain the desired wire diameter, shape, and physical properties. Step 4: Surface Treatment Clean, polish, or cover the wire surface with an insulating layer; Step 5: Cutting and winding Cut the wire to the required length and wind it onto a matching spool or reel.

[0011] In the fourth step of surface treatment, the wire is cleaned by soaking the surface of the wire with a mixture of 90% alcohol and ten times the amount of water, and then dried with hot air at a temperature of 40℃-70℃ for 10-30 minutes.

[0012] Step four, preparing the outer insulation layer of the wire, includes the following steps: Step 1: Prepare materials Prepare granules or powders of polyimide and polyvinyl chloride; The second step is to accurately weigh the polyimide and polyvinyl chloride particles according to the ratio of 60%-80% polyimide and 40%-20% polyvinyl chloride particles. The third step is to put the polyimide and polyvinyl chloride granules or powder mixed according to the formula into the hopper of the extruder; Step 4: Start the extruder and heat the granules or powder to a molten state; Step 5: The molten mixture is extruded through the screw and extrusion head of the extruder and coated onto the surface of the wire. Step 6: During the extrusion process, the temperature is kept stable at 130-150°C and the extrusion speed is kept stable at 15-20 mm / min. Adjust the feed speed of the wire to ensure that the uniformity and thickness of the coating meet the preset values. Step 7: After coating is completed, send the wire into the cooling area to allow the coating to cool and cure.

[0013] In the fourth step, the polyimide is heated at 350℃-410℃ for 30 minutes, and the polyvinyl chloride particles are heated at 150℃-220℃ for 10-16 minutes.

[0014] The method for preparing the second insulating layer in step five includes the following steps. Step 1: Prepare polyurethane gel and ceramsite according to a ratio of 70%-90%: 10%-30%; Step 2: Heating the polyurethane gel Place the polyurethane gel in a container and heat it to the preset melting point temperature to completely melt the polyurethane gel. Step 3: Add expanded clay pebbles Gradually add the specified amount of ceramsite to the molten polyurethane gel and stir to evenly disperse the ceramsite in the polyurethane gel. Step 4: Stir and mix After adding the ceramsite to the polyurethane gel, stir at a stirring rate of 40-60 prm for 13-15 minutes until the mixture of polyurethane gel and ceramsite is homogeneous. Step 5: Load the mixture into the hopper of the extruder; Step 6: Coat the wire surface Start the extruder and extrude the mixture onto the wire surface through the screw and extrusion head of the extruder; during the extrusion process, the extrusion temperature is 130-150℃, the extrusion pressure is 15-25MPa, and the extrusion speed is 15-20 mm / min; Step 8: Cooling and Curing After extrusion coating is completed, the wire is fed into a cooling zone to cool and solidify the mixture, forming a second insulating layer.

[0015] Step six involves sequentially applying a high-temperature resistant coating and a high-temperature resistant, high-reflective heat-insulating coating to the surface of the wire, including the following steps: Step 1: Heat the high-temperature resistant insulating coating; Place the high-temperature resistant insulating coating into a container and heat it to the preset melting point temperature to completely melt the high-temperature resistant insulating coating. Step 2: Heating the high-temperature resistant, high-reflectivity heat-insulating coating Place the high-temperature resistant, high-reflectivity heat-insulating coating into a container, and then heat it to the preset melting point temperature to melt the coating. Step 4: Stir and mix After heating the high-temperature resistant insulating coating and the high-temperature resistant high-reflectivity heat insulation coating, stir at a stirring rate of 40-60 rpm for 13-15 minutes until the coating is uniform. Step 5: Load the high-temperature resistant insulating coating and the high-temperature resistant high-reflectivity heat insulation coating into the hopper of the extruder respectively; Step 6: Coat the wire surface Start the extruder, and through the screw and extrusion head of the extruder, extrude and coat the high-temperature resistant insulating coating and the high-temperature resistant high-reflective heat insulation coating onto the surface of the wire respectively; during the extrusion process, the extrusion temperature is 130-150℃, the extrusion pressure is 15-25MP, and the extrusion speed is 15-20 mm / min; Step 8: Cooling and Curing After extrusion coating is completed, the wire is fed into a cooling zone to cool and solidify the mixture, forming a high-temperature resistant coating and a high-reflectivity heat-insulating protective layer. Beneficial effects

[0016] (1) The present invention improves conductivity by adding a small amount of silver in a suitable ratio, thereby obtaining sufficient conductivity.

[0017] (2) By adding nickel alloy and silver, the present invention improves the durability and service life of the core wire, thereby improving the conductivity of the core wire at high temperature.

[0018] (3) By adding nickel alloy, the present invention resists the corrosion of acidic environment, high temperature gas and corrosive salt solution, and effectively prevents the conductor performance from declining due to high temperature aging.

[0019] (4) The present invention can effectively reduce the heat radiation of the heated oil pipe to the conductive core wire by means of high temperature resistant coating and high temperature resistant high reflective heat insulation coating, thereby reducing the surface temperature of the conductive core wire and further improving the service life of the core wire.

[0020] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a flowchart of the present invention. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention. Example 1

[0024] according to Figure 1 The method for manufacturing a core wire to improve the conductivity of an electric heating core wire in oil pipes, as shown, includes the following steps: Step 1: Prepare raw materials Weigh out the copper, aluminum, nickel alloy, and silver materials according to the specified proportions; Step 2: Molding The copper, aluminum, nickel alloy and silver materials weighed according to the ratio are melted and then poured into the mold to form the shape; Step 3: Form the alloy ingot formed in Step 2 into a wire shape; Step 4: Prepare the outer insulation layer of the wire; Step 5: Create a second layer of insulation for the wire; Step 6: Mix the heat-reflective coating and the heat-resistant coating and apply them to the surface of the wire to complete the preparation.

[0025] Specifically, the proportions of copper, aluminum, nickel alloy, and silver in the raw materials prepared in step one are: copper 50-60%, aluminum 30-40%, nickel alloy 9.0-10%, and silver 0.3-0.6%. In this embodiment, the addition of alloying elements such as aluminum, nickel alloy, and silver not only reduces material costs due to the relatively low prices of aluminum and nickel, but also effectively reduces the overall weight of the core wire compared to pure copper. Although aluminum and nickel have poor conductivity compared to pure copper, the addition of a small amount of silver in the above-mentioned appropriate proportions improves conductivity, still achieving sufficient conductivity. The addition of nickel alloy and silver provides corrosion resistance, thereby improving the durability and service life of the core wire. Due to the addition of nickel alloy, it can resist oxidation and corrosion at high temperatures, thus effectively protecting the manufactured core wire from acidic environments, high-temperature gases, and corrosive salt solutions.

[0026] In this embodiment, the heat-resistant coating is the ZS-1091 high-temperature insulating coating (1800℃) from the prior art; the heat-reflective coating is the DHC330 high-temperature high-reflective heat-insulating coating from the prior art; in actual use, Alesta HR can also be applied to the surface of the wire to protect the surface exposed to extremely high temperatures, up to 550℃, without causing the film to deteriorate.

[0027] Furthermore, the specific process of step two, molding, involves placing the copper selected in step one into a container, heating it to 1100-1200℃ to melt it, then adding aluminum and silver selected in proportion, and continuing to heat it to 1300-1500℃ to add nickel alloy, so that the copper, aluminum, nickel alloy and silver are liquefied, and stirred until uniform, and then placed into a mold to cool and form.

[0028] Furthermore, the equipment for melting copper, aluminum, nickel alloys and silver is an electric arc furnace; the electric arc furnace has a power of 20MW-50MW, and the total weight of copper, aluminum, nickel alloys and silver heated in a single electric arc furnace is 8t-10t; wherein, stirring rods are used to mix the liquid copper, aluminum, nickel alloys and silver; the stirring rods are one or more of the following: Ti-6Al-4V stirring rods, cobalt-based high-temperature alloy stirring rods, alumina ceramic stirring rods and silicon nitride ceramics.

[0029] Furthermore, the method for processing the alloy ingot into wire in step three includes the following steps: The first step is to produce continuous wire from alloy ingots through continuous casting or extrusion. Liquid metal is injected into a forming mold through continuous casting or extrusion processes. Continuous casting involves injecting molten metal into a metal mold and then rapidly cooling and solidifying it to form a continuous casting. Extrusion involves shaping molten metal into continuous wire through extrusion pressure. Step 2: Cooling and Demagnetizing After continuous casting or extrusion, the wire is cooled and demagnetized to reduce internal stress and magnetism in the metal. Step 3: Bending and Stretching Cooled wires are shaped and deformed through bending and stretching processes to obtain the desired wire diameter, shape, and physical properties. Step 4: Surface Treatment As needed, the surface of the wire may be treated, such as cleaning, polishing, or covering with an insulation layer; Step 5: Cutting and winding The wire is cut to the required length and wound onto matching spools or reels for easy transport and use.

[0030] Furthermore, in the fourth step of surface treatment, the wire is cleaned by soaking the surface of the wire with a mixture of 90% alcohol and ten times the amount of water, and then dried with hot air at a temperature of 40℃-70℃ for 10-30 minutes.

[0031] Furthermore, step four, preparing the outer insulation layer of the wire, includes the following steps: Step 1: Prepare materials Prepare polyimide and polyvinyl chloride granules or powders; ensure the quality and purity of the selected materials; The second step is to accurately weigh the polyimide and polyvinyl chloride granules according to the ratio of 60%-80% polyimide to 40%-20% polyvinyl chloride granules. This process requires the use of accurate weighing equipment to ensure accurate proportions. The third step is to put the polyimide and polyvinyl chloride granules or powder mixed according to the formula into the hopper of the extruder; Step 4: Start the extruder and heat the granules or powder to a molten state; Step 5: The molten mixture is extruded through the screw and extrusion head of the extruder and coated onto the surface of the wire; the shape and size of the extrusion head should be determined according to the requirements of the wire. Step 6: During the extrusion process, the temperature is kept stable at 130-150°C and the extrusion speed is kept stable at 15-20 mm / min. Adjust the feed speed of the wire to ensure that the uniformity and thickness of the coating meet the preset values. Step 7: After coating is completed, send the wire into the cooling area to allow the coating to cool and cure.

[0032] Polyimide maintains its strength and stability at high temperatures, withstanding temperatures up to 400°C. It also exhibits excellent chemical resistance, showing relatively low susceptibility to acids, alkalis, organic solvents, and other chemicals. PVC material possesses good weather resistance, able to withstand the effects of ultraviolet radiation, humidity, and oxidation. The core wire is manufactured using the methods described above, effectively extending its service life outdoors.

[0033] Furthermore, in the fourth step, the polyimide is heated at 350℃-410℃ for 25-35 minutes, and the polyvinyl chloride particles are heated at 150℃-220℃ for 10-16 minutes.

[0034] Furthermore, the method for preparing the second insulating layer in step five includes the following steps: Step 1: Prepare polyurethane gel and ceramsite in a ratio of 70%-90%: 10%-30%; ensure the quality and purity of the materials and follow the material handling instructions; Step 2: Heating the polyurethane gel Place the polyurethane gel in a container and heat it to the preset melting point temperature to completely melt the polyurethane gel; use heating equipment such as a hot water bath to ensure that the polyurethane gel is completely melted. Step 3: Add expanded clay pebbles Gradually add the specified amount of ceramsite to the molten polyurethane gel and stir to evenly disperse the ceramsite in the polyurethane gel. Step 4: Stir and mix After adding the ceramsite to the polyurethane gel, stir at a stirring rate of 40-60 prm for 13-15 minutes until the mixture of polyurethane gel and ceramsite is homogeneous. Step 5: Load the mixture into the hopper of the extruder; Step 6: Coat the wire surface Start the extruder and extrude the mixture onto the wire surface through the screw and extrusion head of the extruder; during the extrusion process, the extrusion temperature is 130-150℃, the extrusion pressure is 15-25MPa, and the extrusion speed is 15-20 mm / min; Step 8: Cooling and Curing After extrusion coating is completed, the wire is fed into a cooling zone to cool and solidify the mixture, forming a second insulating layer.

[0035] Further, the first step is to heat the ZS-1091 high-temperature resistant insulating coating (1800℃). Place the ZS-1091 high-temperature resistant insulating coating into a container and heat it to the preset melting point temperature to completely melt the ZS-1091 high-temperature resistant insulating coating. Step 2: Heat the DHC330 high-temperature resistant, high-reflectivity heat-insulating coating. Place the DHC330 high temperature resistant and high reflective heat insulation coating into a container, and then heat it to the preset melting point temperature to melt the DHC330 high temperature resistant and high reflective heat insulation coating. Step 4: Stir and mix After heating ZS-1091 high-temperature resistant insulating coating and DHC330 high-temperature resistant high-reflectivity heat insulation coating, stir at a stirring rate of 40-60 rpm for 13-15 minutes until the coating is uniform. Step 5: Load ZS-1091 high-temperature resistant insulating coating and DHC330 high-temperature resistant high-reflective heat insulation coating into the hopper of the extruder respectively; Step 6: Coat the wire surface Start the extruder, and through the screw and extrusion head of the extruder, extrude and coat the ZS-1091 high temperature resistant insulating coating and DHC330 high temperature resistant high reflective heat insulation coating onto the surface of the wire respectively; during the extrusion process, the extrusion temperature is 130-150℃, the extrusion pressure is 15-25MP, and the extrusion speed is 15-20 mm / min; Step 8: Cooling and Curing After extrusion coating is completed, the wire is fed into a cooling zone to cool and solidify the mixture, forming a high-temperature resistant coating and a high-reflectivity heat-insulating protective layer.

[0036] This invention, through appropriate proportions, not only reduces costs but also improves the conductivity of the core wire by adding a small amount of silver, thereby achieving sufficient conductivity.

[0037] This invention improves the durability and service life of the core wire by adding nickel alloy and silver, thereby enhancing the conductivity of the core wire at high temperatures. Example 2

[0038] according to Figure 1 The method for manufacturing a core wire to improve the conductivity of an electric heating core wire for oil pipes includes the following steps, as shown in Table 1.

[0039]

[0040] Step 1: Prepare raw materials Weigh out the copper, aluminum, nickel alloy, and silver materials according to the specified proportions; Step 2: Molding The copper, aluminum, nickel alloy and silver materials weighed according to the ratio are melted and then poured into the mold to form the shape; Step 3: Form the alloy ingot formed in Step 2 into a wire shape; Step 4: Prepare the outer insulation layer of the wire; Step 5: Create a second layer of insulation for the wire; Step 6: Mix the heat-reflective coating and the heat-resistant coating and apply them to the surface of the wire to complete the preparation.

[0041] In this embodiment, the heat-resistant coating is the ZS-1091 high-temperature insulating coating (1800℃) from the prior art; the heat-reflective coating is the DHC330 high-temperature high-reflective heat-insulating coating from the prior art; in actual use, Alesta HR can also be applied to the surface of the wire to protect the surface exposed to extremely high temperatures, up to 550℃, without causing the film to deteriorate.

[0042] Furthermore, the specific process of step two, molding, involves placing the copper selected in step one into a container, heating it to 1150°C to melt it, then adding aluminum and silver selected in proportion, and continuing to heat it to 1400°C to add a nickel alloy, so that the copper, aluminum, nickel alloy, and silver are liquefied, and stirred until uniform, and then placed into a mold to cool and form.

[0043] Furthermore, the equipment for melting copper, aluminum, nickel alloys and silver is an electric arc furnace; the electric arc furnace has a power of 40MW, and the total weight of copper, aluminum, nickel alloys and silver heated in a single electric arc furnace is 9t.

[0044] Furthermore, the copper, aluminum, nickel alloy and silver liquids are mixed using a stirring rod; the stirring rod is one or more of the following: Ti-6Al-4V stirring rod, cobalt-based high-temperature alloy stirring rod, alumina ceramic stirring rod and silicon nitride ceramic.

[0045] Step three, the method for processing alloy ingots into wire, includes the following steps: The first step is to produce continuous wire from alloy ingots through continuous casting or extrusion. Liquid metal is injected into a forming mold through continuous casting or extrusion processes. Continuous casting involves injecting molten metal into a metal mold and then rapidly cooling and solidifying it to form a continuous casting. Extrusion involves shaping molten metal into continuous wire through extrusion pressure. Step 2: Cooling and Demagnetizing After continuous casting or extrusion, the wire is cooled and demagnetized to reduce internal stress and magnetism in the metal. Step 3: Bending and Stretching Cooled wires are shaped and deformed through bending and stretching processes to obtain the desired wire diameter, shape, and physical properties. Step 4: Surface Treatment As needed, the surface of the wire may be treated, such as cleaning, polishing, or covering with an insulation layer; Step 5: Cutting and winding The wire is cut to the required length and wound onto matching spools or reels for easy transport and use.

[0046] Furthermore, in the fourth step of surface treatment, the wire is cleaned by soaking the surface of the wire with a mixture of 90% alcohol and ten times the amount of water, and then dried with hot air at a temperature of 60°C for 20 minutes.

[0047] Furthermore, step four, preparing the outer insulation layer of the wire, includes the following steps: Step 1: Prepare materials Prepare polyimide and polyvinyl chloride granules or powders; ensure the quality and purity of the selected materials; The second step is to accurately weigh the polyimide and polyvinyl chloride according to the preset ratio (60% polyimide: 40% polyvinyl chloride granules). This process requires the use of accurate weighing equipment to ensure accurate ratio. The third step is to put the polyimide and polyvinyl chloride granules or powder mixed according to the formula into the hopper of the extruder; Step 4: Start the extruder and heat the granules or powder to a molten state; Step 5: The molten mixture is extruded through the screw and extrusion head of the extruder and coated onto the surface of the wire; the shape and size of the extrusion head should be determined according to the requirements of the wire. Step 6: During the extrusion process, the temperature is stabilized at 140°C and the extrusion speed is stabilized at 18 mm / min. The feed speed of the wire is adjusted to ensure that the uniformity and thickness of the coating meet the preset values. Step 7: After coating is completed, send the wire into the cooling area to allow the coating to cool and cure.

[0048] Polyimide maintains its strength and stability at high temperatures, withstanding temperatures up to 400°C. It also exhibits excellent chemical resistance, showing relatively low susceptibility to acids, alkalis, organic solvents, and other chemicals. PVC material possesses good weather resistance, able to withstand the effects of ultraviolet radiation, humidity, and oxidation. The core wire is manufactured using the methods described above, effectively extending its service life outdoors.

[0049] Furthermore, in the fourth step, the polyimide is heated to 380°C for 30 minutes, and the polyvinyl chloride particles are heated to 190°C for 15 minutes.

[0050] Furthermore, the method for preparing the second insulating layer in step five includes the following steps: Step 1: Prepare polyurethane gel and ceramsite in a 70%:30% ratio; ensure the quality and purity of the materials and follow the material handling instructions; Step 2: Heating the polyurethane gel Place the polyurethane gel in a container and heat it to the preset melting point temperature to completely melt the polyurethane gel; use heating equipment such as a hot water bath to ensure that the polyurethane gel is completely melted. Step 3: Add expanded clay pebbles Gradually add the specified amount of ceramsite to the molten polyurethane gel and stir to evenly disperse the ceramsite in the polyurethane gel. Step 4: Stir and mix After adding the ceramsite to the polyurethane gel, stir at a stirring rate of 50 prm for 14 minutes until the mixture of polyurethane gel and ceramsite is homogeneous. Step 5: Load the mixture into the hopper of the extruder; Step 6: Coat the wire surface Start the extruder, and extrude and coat the mixture onto the wire surface through the screw and extrusion head of the extruder; during the extrusion process, the extrusion temperature is 140℃, the extrusion pressure is 20MP, and the extrusion speed is 18 mm / min; Step 8: Cooling and Curing After extrusion coating is completed, the wire is fed into a cooling zone to cool and solidify the mixture, forming a second insulating layer.

[0051] This invention, through appropriate proportions, not only reduces costs but also improves the conductivity of the core wire by adding a small amount of silver, thereby achieving sufficient conductivity.

[0052] This invention improves the durability and service life of the core wire by adding nickel alloy and silver, thereby enhancing the conductivity of the core wire at high temperatures.

[0053] This invention effectively reduces the heat radiation from heated oil pipes to the conductive core wire through double insulation, lowers the surface temperature of the conductive core wire, and further improves the service life of the conductive core wire. Example 3

[0054] The process flow is the same as in Example 1, except that the proportions of copper, aluminum, nickel alloy and silver in the raw materials are shown in Table 2 below.

[0055] Compared with conventional electric heating core wires (pure copper) for oil pipes of the same specifications, through comparative experiments in Examples 2 and 3, the conductive core wire of this invention contains 30-40% aluminum, effectively reducing the core wire weight by 10-15%; the addition of a small amount of silver to the raw materials improves conductivity by more than 5%; in addition, the outer layer of the core wire is coated with ZS-1091 high-temperature resistant insulating coating (1800℃) + DHC330 high-temperature resistant high-reflective heat-insulating coating, which improves the overall conductivity of the core wire by more than 15%.

[0056] This invention, through the addition of nickel alloy, resists the corrosion of acidic environments, high-temperature gases, and corrosive salt solutions, thereby effectively preventing the degradation of conductor performance caused by high-temperature aging of the core wire.

[0057] Where there is no conflict, those skilled in the art can combine the relevant technical features in the above examples according to the actual situation to achieve the corresponding technical effects. Specific details of the various combinations will not be elaborated here.

[0058] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0059] Furthermore, the use of terms such as "first" and "second" in this invention is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features.

[0060] The above description is merely a preferred embodiment of the present invention. The present invention is not limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. Any simple modifications, equivalent variations, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for manufacturing a core wire to improve the conductivity of an electric heating core wire for oil pipes, characterized in that: Includes the following steps, Step 1: Prepare raw materials Weigh out copper, aluminum, nickel alloy, and silver materials according to the following proportions: copper 50-60%, aluminum 30-40%, nickel alloy 9.0-10%, and silver 0.3-0.6%. Step 2: Molding After melting the copper, aluminum, nickel alloy and silver materials weighed according to the ratio, the mixture is poured into a mold for shaping. The specific process is to put the copper selected according to the ratio in step one into a container and heat it to 1100-1200℃ to melt it. Then, aluminum and silver selected according to the ratio are added, and the temperature is continuously raised to 1300-1500℃. The nickel alloy is then added to liquefy the copper, aluminum, nickel alloy and silver, and the mixture is stirred until uniform. Finally, the mixture is poured into a mold and cooled to shape. Step 3: Form the alloy ingot formed in Step 2 into a wire shape; Step 4: Prepare the outer insulation layer of the wire; Step 5: Create a second layer of insulation for the wire; Step 6: Mix the heat-reflective coating and the heat-resistant coating and apply them to the surface of the wire to complete the preparation.

2. The method for manufacturing a core wire to improve the conductivity of an electric heating core wire for oil pipes as described in claim 1, characterized in that: The equipment for melting copper, aluminum, nickel alloys and silver is an electric arc furnace; the electric arc furnace has a power of 20MW-50MW, and the total weight of copper, aluminum, nickel alloys and silver heated in a single electric arc furnace is 8t-10t; wherein, the copper, aluminum, nickel alloys and silver liquids are mixed using a stirring rod; the stirring rod is one or more of the following: Ti-6Al-4V stirring rod, cobalt-based high-temperature alloy stirring rod, alumina ceramic stirring rod and silicon nitride ceramic.

3. The method for manufacturing a core wire to improve the conductivity of an electric heating core wire for oil pipes as described in claim 1, characterized in that: The method for processing alloy ingots into wire in step three includes the following steps: The first step is to produce continuous wire from alloy ingots by continuous casting or extrusion. Step 2: Cooling and Demagnetizing After continuous casting or extrusion, the wire is cooled and demagnetized. Step 3: Bending and Stretching Cooled wires are shaped and deformed through bending and stretching processes to obtain the desired wire diameter, shape, and physical properties. Step 4: Surface Treatment Clean, polish, or cover the wire surface with an insulating layer; Step 5: Cutting and winding Cut the wire to the required length and wind it onto a matching spool or reel.

4. The method for manufacturing a core wire to improve the conductivity of an electric heating core wire for oil pipes as described in claim 3, characterized in that: In the fourth step of surface treatment, the wire is cleaned by soaking the surface of the wire with a mixture of 90% alcohol and ten times the amount of water, and then dried with hot air at a temperature of 40℃-70℃ for 10-30 minutes.

5. The method for manufacturing a core wire to improve the conductivity of an electric heating core wire for oil pipes as described in claim 1, characterized in that: Step four, preparing the outer insulation layer of the wire, includes the following steps: Step 1: Prepare materials Prepare granules or powders of polyimide and polyvinyl chloride; The second step is to accurately weigh the polyimide and polyvinyl chloride particles according to the ratio of 60%-80% polyimide and 40%-20% polyvinyl chloride particles. The third step is to put the polyimide and polyvinyl chloride granules or powder mixed according to the formula into the hopper of the extruder; Step 4: Start the extruder and heat the granules or powder to a molten state; Step 5: The molten mixture is extruded through the screw and extrusion head of the extruder and coated onto the surface of the wire. Step 6: During the extrusion process, the temperature is kept stable at 130-150°C and the extrusion speed is kept stable at 15-20 mm / min. Adjust the feed speed of the wire to ensure that the uniformity and thickness of the coating meet the preset values. Step 7: After coating is completed, send the wire into the cooling area to allow the coating to cool and cure.

6. The method for manufacturing a core wire to improve the conductivity of an electric heating core wire for oil pipes as described in claim 5, characterized in that: In the fourth step, the polyimide is heated at 350℃-410℃ for 30 minutes, and the polyvinyl chloride particles are heated at 150℃-220℃ for 10-16 minutes.

7. The method for manufacturing a core wire to improve the conductivity of an electric heating core wire for oil pipes as described in claim 1, characterized in that: The method for preparing the second insulating layer in step five includes the following steps. Step 1: Prepare polyurethane gel and ceramsite according to a ratio of 70%-90%: 10%-30%; Step 2: Heating the polyurethane gel Place the polyurethane gel in a container and heat it to the preset melting point temperature to completely melt the polyurethane gel. Step 3: Add expanded clay pebbles Gradually add the specified amount of ceramsite to the molten polyurethane gel and stir to evenly disperse the ceramsite in the polyurethane gel. Step 4: Stir and mix After adding the ceramsite to the polyurethane gel, stir at a stirring rate of 40-60 prm for 13-15 minutes until the mixture of polyurethane gel and ceramsite is homogeneous. Step 5: Load the mixture into the hopper of the extruder; Step 6: Coat the wire surface Start the extruder and extrude the mixture onto the wire surface through the screw and extrusion head of the extruder; during the extrusion process, the extrusion temperature is 130-150℃, the extrusion pressure is 15-25MPa, and the extrusion speed is 15-20 mm / min; Step 8: Cooling and Curing After extrusion coating is completed, the wire is fed into a cooling zone to cool and solidify the mixture, forming a second insulating layer.

8. The method for manufacturing a core wire to improve the conductivity of an electric heating core wire for oil pipes as described in claim 1, characterized in that: Step six involves sequentially applying a high-temperature resistant coating and a high-temperature resistant, high-reflective heat-insulating coating to the surface of the wire, including the following steps: Step 1: Heat the high-temperature resistant insulating coating; Place the high-temperature resistant insulating coating into a container and heat it to the preset melting point temperature to completely melt the high-temperature resistant insulating coating. Step 2: Heating the high-temperature resistant, high-reflectivity heat-insulating coating Place the high-temperature resistant, high-reflectivity heat-insulating coating into a container, and then heat it to the preset melting point temperature to melt the coating. Step 4: Stir and mix After heating the high-temperature resistant insulating coating and the high-temperature resistant high-reflectivity heat insulation coating, stir at a stirring rate of 40-60 rpm for 13-15 minutes until the coating is uniform. Step 5: Load the high-temperature resistant insulating coating and the high-temperature resistant high-reflectivity heat insulation coating into the hopper of the extruder respectively; Step 6: Coat the wire surface Start the extruder, and through the screw and extrusion head of the extruder, extrude and coat the high-temperature resistant insulating coating and the high-temperature resistant high-reflective heat insulation coating onto the surface of the wire respectively; during the extrusion process, the extrusion temperature is 130-150℃, the extrusion pressure is 15-25MP, and the extrusion speed is 15-20 mm / min; Step 8: Cooling and Curing After extrusion coating is completed, the wire is fed into a cooling zone to cool and solidify the mixture, forming a high-temperature resistant coating and a high-reflectivity heat-insulating protective layer.

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