A power-driven cable for a hot furnace steel transfer vehicle and its manufacturing method

Abstract

The present invention discloses a power-driven cable for a hot furnace steel transfer vehicle and a manufacturing method thereof, which includes an outer protective layer, an isolation layer, a filling layer and a three-phase cable core. The outer of the three-phase cable core is wrapped with an isolation layer; the outer of the isolation layer is wrapped with an outer protective layer; the gaps between the three-phase cable cores and in the middle of the isolation layer are provided with a filling layer; the cable core includes a conductor layer and an insulating layer wrapped outside the conductor layer. The conductor layer is made of a nickel-plated soft copper conductor material; the insulating layer is made of a magnesium oxide high-temperature resistant tape material; the isolation layer is formed by overlapping and wrapping multiple layers of ceramized mica tape; the filling layer is composed of dust-free rock wool ropes; the outer protective layer is made of nickel-plated steel strip metal interlocking armor; a graphite layer or metal paint is coated on the outer protective layer. The cable has a long service life and high safety performance, can meet the use requirements of the hot furnace steel transfer vehicle, and at the same time, the manufacturing method of the cable is also simple and easy to implement.

Description

Technical Field

[0001] The present invention relates to the field of electric power technology, and particularly to a power-driven cable for a hot furnace steel transfer vehicle and a manufacturing method thereof. Background Art

[0002] In the modern steel manufacturing process, to transport the hot molten steel refined in the converter to the next continuous casting or ingot casting work area, an automatic conveyor belt device is generally used for transportation to the next process. However, modern large-scale steel mills have large converter production capacities, generally capable of producing (200 - 400) tons. Large converters have high production efficiency and lower energy consumption. Since the nearby conveyor belts have limited capacity to handle the production, the vast majority of the molten steel needs to be transported to various scattered work areas or workshops. To reduce energy losses, avoid significant temperature drops and cooling, or solidification that may cause the molten steel to adhere to the ladle and be scrapped, a hot charging and hot delivery process needs to be adopted. Moreover, electric rail transportation with a short distance and high efficiency is required to transport the molten steel to the next work area within the shortest time, generally with a required transportation distance not exceeding 300 meters.

[0003] The hot metal traction locomotive system has become the best transportation tool. The hot metal traction locomotive system consists of a molten steel ladle, a traction locomotive, a control system, a bogie, a power system, and a track, etc. Among them, the power system uses a motor, a reel, and a power-driven cable; the reel is on the locomotive, fixing one end of the cable to supply power to the motor (in some cases, heating the hot metal in the molten steel ladle), and the other end is connected to external power at the middle position outside the track. The reel's retraction and extension are controlled by a steering device to form a complete walking process. Forward and reverse walking can reduce the cable weight and the reel weight, and reduce cable damage.

[0004] Since the weight of the transported hot metal is generally 20 - 50 tons, plus the weights of the molten steel ladle, locomotive, reel, and cable are relatively large, a wireless battery car drive cannot be used. Instead, a 380V industrial frequency AC power drive is suitable, with a drive power of approximately (80 - 250) kW;

[0005] According to the production efficiency and transportation requirements of the steel converter, it is generally required to transport 20 - 40 times a day. This causes relatively large mechanical damage to the cable. Ordinary high-power plastic-insulated power cables are designed for fixed laying without movement and are not in such a high-temperature environment. The steel design requires a cable life of 3 months and then replacement.

[0006] For the above reasons, the power-driven cable for the hot furnace steel transfer vehicle needs special design and must meet the following requirements:

[0007] (1) The overall flexibility of the cable is good; high-frequency back-and-forth movement will not damage the conductor, ensuring that the power current-carrying capacity does not decrease; the insulation layer and the sheath layer also have a good bending rate with a small radius;

[0008] (2) It has good bending damage resistance for insulation and sheath, the insulation resistance and electrical strength do not decrease, and the sheath will not be mechanically damaged;

[0009] (3) Since the cable is outside the track, it is most vulnerable to being splashed with molten steel. When the molten steel on the outer layer falls, the temperature is about 1000 degrees. When the cable surface is splashed with molten steel, all the structural materials of the cable should not be damaged after withstanding high temperature for a short time;

[0010] (4) The cable can still be guaranteed not to be damaged by high temperature even if it is splashed with molten steel twice in the same place, and the molten steel can fall off by itself after cooling.

[0011] However, the cables used in existing hot furnace steel transfer vehicles mainly have the following problems:

[0012] (1) The conductor uses a pure copper conductor, which has insufficient high temperature resistance, slightly poor strength, and is easy to break, resulting in a shortened cable life;

[0013] (2) The insulation sheath uses plastic materials, which have poor high temperature resistance. Damage at high temperature causes insulation voltage breakdown, and the sheath is mechanically deformed by heat, damaging the cable, such as cross-linked polyethylene material (90°C) and silicone rubber material (180°C);

[0014] (3) When splashed with molten steel, the plastic cable cannot protect itself and fails and is damaged. When some cables are added with steel wire braided armor, it cannot ensure that the plastic sheath is burned out. The molten steel cools into blocks and adheres to the steel wire, damaging the adjacent coils of the cable when the cable is wound around the reel.

[0015] (4) The service life of the cable is less than 3 months.

[0016] Therefore, providing a cable for hot furnace steel transfer vehicles with high temperature resistance, good bending property, good insulation property, and long service life is a problem that those skilled in the art need to solve. Summary of the Invention

[0017] In view of the above problems existing in the cables used in existing hot furnace steel transfer vehicles, the object of the present invention is to provide a power drive cable for hot furnace steel transfer vehicles and its manufacturing method. The cable has a long service life, high safety performance, and good cost performance, can meet the use requirements of hot furnace steel transfer vehicles, and at the same time, the manufacturing method of the cable is also simple and easy to implement.

[0018] To achieve the above object, the power drive cable for hot furnace steel transfer vehicles provided by the present invention includes an outer sheath, an isolation layer, a filling layer, and a three-phase cable core. The isolation layer is wrapped around the outside of the three-phase cable core; the outer sheath is wrapped around the outside of the isolation layer; the filling layer is arranged in the gaps between the three-phase cable cores and in the middle of the isolation layer;

[0019] The cable core includes a conductor layer and an insulating layer wrapped around the outside of the conductor layer. The conductor layer is made of nickel-plated soft copper conductor material; the insulating layer is made of magnesium oxide high-temperature resistant tape material; the isolation layer is formed by overlapping and wrapping multiple layers of ceramized mica tape; the filling layer is composed of dust-free rock wool ropes; the outer sheath is made of nickel-plated steel strip metal interlocking armor; a graphite layer or metal paint is coated on the outer sheath.

[0020] Further, the conductor layer is formed by composite stranding of multiple fine nickel-plated copper wires.

[0021] Further, the insulating layer is made by using glass fiber as the reinforcement base, and a solid state formed by silica gel and magnesium oxide powder is adhered between two layers of glass fiber.

[0022] Further, the insulating layer is formed by wrapping 4 - 9 layers, where the inner two layers use plastic-coated magnesium oxide high-temperature resistant tape, and the outside uses non-plastic-coated high-temperature resistant tape.

[0023] Further, the thickness of the insulating layer tape material is 0.1mm - 0.3mm.

[0024] Further, the isolation layer can be wrapped in multiple layers according to the requirements of the wire specification size and insulation thickness.

[0025] Further, the thickness of the nickel-plated steel strip is 1.0mm - 2.0mm.

[0026] Further, the three-phase cable cores are arranged in an equilateral triangle distribution.

[0027] The present invention also provides a manufacturing method for the electric drive cable of the above-mentioned hot furnace steel transfer vehicle, including the following steps:

[0028] (1) Preparation of the conductor layer: A conductor with good high-temperature conductivity is drawn, stranded, and then complex-stranded to form the conductor layer;

[0029] (2) Preparation of the three-phase cable core: An insulating layer is wrapped around the outside of the conductor layer to prepare an insulated wire core, and then combined with the filling layer to strangle into a three-phase cable core;

[0030] (3) Wrapping an isolation layer around the outside of the three-phase cable core;

[0031] (4) Wrapping an outer sheath around the outside of the isolation layer.

[0032] Further, after the insulating layer is wrapped, the insulated wire core is baked in an oven to remove moisture.

[0033] Compared with the prior art, the electric drive cable of the hot furnace steel transfer vehicle provided by the present invention has the following beneficial effects:

[0034] (1) Compared with traditional plastic-insulated cables, it can ensure that the cable will not be damaged when molten steel drops, and all materials inside the cable can withstand high temperatures above 1000°C;

[0035] (2) It has good reel bendability, and repeated bending will not damage the internal insulation, causing electrical insulation performance and electrical withstand voltage breakdown;

[0036] (3) The outer sheath is made of metal material and will not be mechanically damaged when being towed on the upper tray and along the track side;

[0037] (4) It can prevent molten iron drops multiple times and automatically detach, without causing tip damage between the sheaths;

[0038] (5) It is safe and fireproof. All materials used in the cable are non-flammable and will not cause a fire when molten iron drops;

[0039] (6) It is environmentally friendly and pollution-free. None of the cable materials will harm the environment and are all easy to recycle and reuse. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The present invention will be further described below in conjunction with the drawings and specific embodiments.

[0041] Figure 1 It is a cross-sectional view of the power-driven cable for the hot furnace steel transfer vehicle in this example;

[0042] Figure 2 It is a longitudinal-sectional view of the magnesium oxide insulating tape of the power-driven cable for the hot furnace steel transfer vehicle in this example.

[0043] The meanings of the reference numerals in the drawings are as follows:

[0044] Outer sheath 1, isolation layer 2, filling layer 3, insulating layer 4, conductor layer 5, non-alkali glass fiber braided layer 6, magnesium oxide and silica gel mixed layer 7. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0045] In order to make the technical means, creative features, achieved purposes and effects of the present invention easy to understand, the present invention will be further elaborated below in conjunction with specific drawings.

[0046] Aiming at the problems existing in the power-driven cable of the existing hot furnace steel transfer vehicle, this example provides a new solution. The cable provided by this solution has high temperature resistance, good bendability, good insulation, long service life, and high safety and reliability.

[0047] As Figure 1As shown in the figure, the electric drive cable for the hot furnace steel transfer vehicle provided in this example includes an outer sheath 1, an isolation layer 2, a filling layer 3, and a three-phase cable core. Among them, the three-phase cable cores are arranged in an equilateral triangle distribution. The outside of the three-phase cable cores is wrapped with an isolation layer 2, and the outside of the isolation layer 2 is wrapped with an outer sheath 1. The filling layer 3 is arranged in the gaps between the three-phase cable cores and in the middle of the isolation layer 2.

[0048] Specifically, the cable core is composed of a conductor layer 5 and an insulating layer 4 wrapped around the outside of the conductor layer 5. Among them, the conductor layer 5 is used to conduct electricity, and it is preferably made of nickel-plated soft copper conductor material; the insulating layer 4 is used to protect the conductor layer 5 and form an insulating space to the outside.

[0049] As an example, the conductor layer 5 in this example is formed by composite stranding of multiple fine nickel-plated copper wires, and its internal stranding structure does not need to be compacted into a shape, but is in a natural circular shape. With such a structure, the flexibility of the conductor layer 5 can be improved, which is convenient for laying and construction installation. Especially when in an extremely narrow line and bunch laying, the bending performance of the wire can be greatly improved. Nickel can withstand temperatures above 1200 °C, and at the same time, the nickel-plated copper conductor also has better corrosion resistance and oxidation resistance.

[0050] The insulating layer 4 is formed by wrapping multiple layers (5 - 8 layers) of magnesium oxide high-temperature resistant tape material. Specifically, when setting, it is made with glass fiber as the strengthening base, and a solid formed by silica gel and magnesium oxide powder is adhered between two layers of glass fiber.

[0051] Among them, the inner two layers are tightly wrapped on the conductor layer 5 with coated magnesium oxide high-temperature resistant tape, and the outside uses non-coated magnesium oxide high-temperature resistant tape.

[0052] As Figure 2 As shown in the figure, as an example, the insulating layer 4 in this example includes two layers of non-alkali glass fiber braided layers 6 and a magnesium oxide and silica gel mixed layer 7 located in the middle. Such a structure forms a tape with a thickness of 0.2 mm. Magnesium oxide can withstand high temperatures up to 2800 °C, which is the best high-temperature resistant material. It can protect the insulating layer 4 from being damaged by high temperatures and affecting the electrical performance. At the same time, magnesium oxide has certain insulating properties, which can prevent electrical voltage breakdown between the outer sheath 1 and the conductor layer 5.

[0053] The isolation layer 2 is used to further improve the safety and reliability of the conductor layer. Preferably, the isolation layer 2 in this example is an auxiliary structural layer, which is formed by overlapping and wrapping multiple layers of ceramicized mica tape. The double-sided reinforced synthetic ceramicized mica tape material mainly plays the roles of withstanding high-temperature damage, wrapping the cable core, heat insulation, and insulation.

[0054] It should be noted here that the insulating layer 4 in this example is a key structure. When specifically setting the thickness of the mica tape in the isolation layer 2, first, the withstand voltage performance and electrical insulation performance of the insulating layer 4 must be ensured. Different thickness requirements are based on the wire gauge size. The mutual cooperation between the two structures enables the insulating layer 4 to achieve withstand voltage breakdown, an insulation resistance of 100 MΩ, and an electrical performance guarantee of no breakdown under 3500 V voltage for 5 minutes, thus ensuring the safety and reliability of the electric drive cable for the hot furnace steel transfer vehicle.

[0055] The filling layer 3 is arranged in the gaps between the three-phase cable cores and between the isolation layer 2 to make the overall structure of the cable round.

[0056] As an example, the filling layer 3 in this example is preferably composed of dust-free rock wool ropes, which will not decompose at temperatures above 1500 °C and do not have electrical conductivity, ensuring the safety and reliability of the cable.

[0057] The outer sheath 1 in this example is preferably made of nickel-plated steel strip metal. Specifically, a relatively narrow nickel-plated steel strip with a thickness of 1.27 mm is used and processed by interlocking armoring. With such a structural setting, after the cable is bent, it can be tightly buckled with each other to form a sealed and slidable outer sheath, greatly improving the bending flexibility of the cable and ensuring the bending performance of the outer sheath 1.

[0058] In addition, a thin graphite layer or metal paint is applied after interlocking armoring to form an integrated protective layer. With such a setting, when molten iron slag drips on the nickel-plated steel strip of the outer sheath 1, it can peel off together with the graphite. If molten iron drips at the same position again, the nickel-plated layer is also heat-resistant and can be peeled off without sticking to the steel layer and does not affect the mutual movement between the steel strips.

[0059] The electric drive cable for the hot furnace steel transfer vehicle based on the above structural setting has the following beneficial effects in specific applications:

[0060] (1) Compared with traditional plastic-insulated cables, it can ensure that the cable will not be damaged when molten steel drips, and all materials inside the cable are heat-resistant above 1000 °C;

[0061] (2) It has good reel bending performance, and repeated bending will not damage the internal insulation, causing electrical insulation performance and electrical withstand voltage breakdown;

[0062] (3) The outer sheath is made of metal material and will not be mechanically damaged when being towed on the upper tray and along the track side;

[0063] (4) It can prevent molten iron from dripping multiple times and automatically detach, and will not cause tip damage between the sheaths;

[0064] (5) It is safe and fireproof. All materials used in the cable are not flammable and will not cause a fire when molten iron drips;

[0065] (6) Environmentally friendly and pollution-free. None of the cable materials will harm the environment and they are all easy to recycle and reuse.

[0066] Meanwhile, this embodiment also provides a manufacturing method for the electric drive cable of the above-mentioned hot furnace steel transfer vehicle, including the following steps:

[0067] (1) Preparation of the conductor layer. The conductor with good high-temperature conductivity is drawn, bunched, and stranding-reeled to form the conductor layer.

[0068] (2) Preparation of the three-phase cable core. An insulating layer is wrapped around the outside of the conductor layer to prepare an insulated wire core, and then it is stranded with a filling layer to form a three-phase cable core.

[0069] (3) Wrap an isolation layer around the outside of the three-phase cable core.

[0070] (4) Wrap an outer sheath around the outside of the isolation layer.

[0071] The following combines specific embodiments to detail the manufacturing method of the electric drive cable of the hot furnace steel transfer vehicle provided in this embodiment, including the following four steps:

[0072] (1) Implementation of the production of the conductor layer 5

[0073] The conductor layer 5 is made of the 5th kind of metal-coated soft copper conductor material specified in the standard (GB / T 3956). First, a small wire drawing machine is used. The pure copper wire is gradually drawn through 24 dies to reach the specified diameter of the fine round copper single wire, and then double-layer nickel plating is carried out. Such a setting makes the conductor layer 5 more stable; after the plated single wires are divided into coils, they are bunched into stranded wires by a bunching machine, and the stranded wires are further stranding-reeled by a cage stranding machine to form a soft conductor layer. With such a structural setting, on the one hand, it can improve the flexibility of the conductor layer, facilitate laying and construction installation, especially greatly improve the bending performance of the conductor layer when in extremely narrow lines and bunching laying. At the same time, the nickel-plated conductor layer also has better corrosion resistance, oxidation resistance, and high-temperature resistance characteristics.

[0074] (2) Implementation of the insulating layer 4

[0075] The insulating layer 4 is formed by multi-layer winding of magnesium oxide composite tape. Specifically, according to the wire specification size, to meet the requirement of the insulation thickness, a six-layer winding machine is used. If it is more than six layers, it is wound in two times, and the overlapping rate is 45% - 50%, achieving the effect of one layer being equivalent to two layers. After winding, the insulated wire core is dried in an oven at 120 °C for 2 hours to remove moisture, which can ensure the insulation resistance and high-voltage resistance performance of the cable; the magnesium oxide composite tape structure is made by mixing magnesium oxide powder and silica gel, bonding them between double-layer alkali-free glass fiber meshes, and drying the solvent to form.

[0076] (3) Implementation of cable stranding and wrapping

[0077] The three-phase insulated wire cores are stranded into a circular structure in a right-handed direction on a cabling machine, and the gaps between the insulated cores are filled and rounded with a non-rock salt rope of appropriate size. The outside is wrapped with 1 - 2 layers (two layers are used for an outer diameter greater than 40 mm) of an isolating layer 2 in a normal process with an overlap to prevent mechanical damage to the insulating layer 4 when the outer sheath 1 is bent.

[0078] (4) Implementation of the outer sheath 1

[0079] The outer sheath 1 is made of nickel-plated stainless steel strip with a small width and a thickness of 1.27 mm, and is produced with a double-layer overlap on an interlocking armoring machine to form a relatively slidable armored layer. Such a structural setting can improve the bending performance of the cable; after completion, a graphite layer is sprayed and dried online with a heater about 2 meters long to ensure the tightness of the graphite layer, and the whole cable production is completed and wound onto a reel for packaging.

[0080] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and what is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. A power-driven cable for a hot furnace steel transfer vehicle, Characterized in that, It includes an outer sheath, an isolation layer, a filling layer and a three-phase cable core. The three-phase cable core is arranged in an equilateral triangle distribution. An isolation layer is wrapped around the outside; an outer sheath is wrapped around the outside of the isolation layer; a filling layer is arranged in the gaps between the three-phase cable cores and in the middle of the isolation layer; The cable core includes a conductor layer and an insulating layer wrapped around the outside of the conductor layer. The conductor layer is made of nickel-plated soft copper conductor material and is formed by composite stranding of multiple fine nickel-plated copper wires; the insulating layer is made of magnesium oxide high-temperature resistant tape material; the isolation layer is made of ceramicized mica tape by overlapping multiple layers; the filling layer is composed of dust-free rock wool rope; the outer sheath is made of nickel-plated steel strip metal interlocking armor; a graphite layer or metal paint is coated on the outer sheath.

2. The power-driven cable for a hot furnace steel transfer vehicle according to claim 1, Characterized in that, The insulating layer is made of glass fiber as the strengthening base, and a solid state formed by silica gel and magnesium oxide powder is adhered between two layers of glass fiber.

3. The power-driven cable for a hot furnace steel transfer vehicle according to claim 1, Characterized in that, The insulating layer is wound by 4-9 layers, of which the inner two layers use plastic-coated magnesium oxide high-temperature resistant tape, and the outside uses non-plastic-coated high-temperature resistant tape.

4. The power-driven cable for a hot furnace steel transfer vehicle according to claim 2, Characterized in that, The thickness of the tape material used for the insulating layer is 0.1mm - 0.3mm.

5. The power-driven cable for a hot furnace steel transfer vehicle according to claim 1, Characterized in that, The isolation layer can be wrapped in multiple layers according to the requirements of wire specifications and insulation thickness.

6. The power-driven cable for a hot furnace steel transfer vehicle according to claim 1, Characterized in that, The thickness of the nickel-plated steel strip is 1.0mm - 2.0mm.

7. A manufacturing method of the power-driven cable for a hot furnace steel transfer vehicle according to any one of claims 1-6, Characterized in that, It includes the following steps: (1) Preparation of the conductor layer, pulling, bunching and composite stranding a conductor with good high-temperature conductive performance to form the conductor layer; (2) Preparation of the three-phase cable core, wrapping an insulating layer around the outside of the conductor layer to prepare an insulated wire core, and then stranding it with a filling layer to form a three-phase cable core; (3) Wrapping an isolation layer around the outside of the three-phase cable core; (4) Wrapping an outer sheath around the outside of the isolation layer.

8. The manufacturing method of the power-driven cable for a hot furnace steel transfer vehicle according to claim 7, Characterized in that, The insulated wire core after the insulating layer is wrapped is baked in an oven to remove moisture.

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