Variable-frequency mobile cable for ship and maritime work platform

Abstract

The utility model discloses a frequency conversion mobile cable for ships and maritime work platforms, which comprises a cable core, an inner sheath, a braided shielding layer and an outer sheath which are arranged in sequence, the cable core comprises a conductor and an insulating layer arranged on the outer side of the conductor, the conductor is a tinned class 5 bending-resistant tinned copper conductor, and the insulating layer is arranged on the outer side of the conductor. The insulating layer is made of ethylene propylene rubber; the inner sheath and the outer sheath are made of polyurethane, and the braided shielding layer is made of composite aramid fibers. Through a special conductor material, the conductor can be bent and moved for multiple times without generating deformation and burrs, and an insulating layer is not damaged; ethylene propylene rubber is used as an insulation layer material to improve insulation flexibility, the inner sheath and the outer sheath are made of polyurethane and have excellent strength and wear resistance, and meanwhile, the braided shielding layer is braided by composite aramid fibers, so that the risk that broken wires of the braided shielding layer pierce the inner sheath and damage the insulation layer in the moving process of the cable is reduced.

Description

Technical Field

[0001] This utility model relates to cable structures, and more particularly to a frequency conversion mobile cable for ships and offshore platforms. Background Technology

[0002] In recent years, with the transformation of the global energy structure and the rapid development of marine engineering, the shipbuilding industry has increasingly demanded energy conservation, emission reduction, and efficient operation. Variable frequency drive (VFD) technology, as a highly efficient and energy-saving power control technology, has been widely used in ship power systems, and VFD cables, as an important component of these systems, are seeing increasing usage. Due to the limited space inside ships and the compact arrangement of equipment and cables, cables primarily move within the ship's space using a cable chain system. Cable chains offer good bending freedom, adapting to the complex layout and movement conditions inside the ship. Furthermore, ships experience dynamic conditions such as swaying, vibration, and deformation during navigation, and using cable chains ensures stable transmission and reliable operation. Conventional marine VFD cables are limited to fixed installations and cannot meet the requirement of cables moving with equipment. Existing mobile power cables lack the anti-interference capabilities to meet the shielding performance requirements of VFD power systems. Therefore, there is an urgent need for a mobile marine VFD cable to meet the specific requirements of shipboard applications.

[0003] The shortcomings of existing technical solutions and products:

[0004] 1. Variable frequency cables cannot meet the operating conditions of dynamic operation. If dynamic operation is required, the cable will be damaged and its service life will be greatly reduced.

[0005] 2. Drag chain cables can meet the operating conditions of dynamic operation, but their shielding effect is poor. When the frequency converter is running, the cable shielding effect is poor, which will cause electromagnetic interference to other facilities. Summary of the Invention

[0006] This utility model overcomes the shortcomings of the prior art and provides a frequency conversion mobile cable for ships and offshore platforms.

[0007] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0008] A variable frequency mobile cable for ships and offshore platforms includes a cable core, an inner sheath, a braided shielding layer, and an outer sheath arranged sequentially. The cable core includes a conductor and an insulation layer disposed outside the conductor. The conductor is a tin-plated Category 5 tin-plated copper conductor, and the insulation layer is ethylene propylene rubber. The inner and outer sheaths are made of polyurethane, and the braided shielding layer is made of composite aramid fiber.

[0009] More specifically, the conductor includes several tin-plated copper monofilaments, several tin-plated copper monofilaments are bundled together in the same direction to form a strand, and several strands are twisted together in the same direction to form a conductor, and the direction of the cable core is the same as the direction of the twisting.

[0010] More specifically, the bundle pitch ratio of the tin-plated copper monofilament is 20-25 times; the twisted pitch ratio of the inner strands is 15-20 times, and the twisted pitch ratio of the outermost strands is 10-12 times; the cabling pitch ratio of the cable core is less than or equal to 9 times.

[0011] More specifically, the composite aramid fiber includes aramid fibers and tin-plated copper wound around the aramid fibers.

[0012] More specifically, a reinforcing nonwoven fabric is wrapped between the conductor and the insulating layer.

[0013] More specifically, a shielding layer is provided between the inner sheath and the braided shielding layer.

[0014] More specifically, the shielding layer is configured as a copper-plastic composite strip, with the copper side of the copper-plastic composite strip facing the side of the woven shielding layer.

[0015] More specifically, an isolation layer is provided between the woven shielding layer and the outer sheath.

[0016] More specifically, the cable core is provided with a power unit and a ground unit twisted together. The power unit includes a power conductor and a power insulation layer extruded on the outside of the power conductor. The ground unit includes a ground conductor and a ground insulation layer extruded on the outside of the ground conductor.

[0017] More specifically, three power units and three ground wire units are provided. The three ground wire units are located outside the power units. Each power unit is tangentially arranged to the other two power units, and each ground wire unit is tangentially arranged to the other two power units.

[0018] This utility model solves the defects existing in the background technology, and has the following beneficial effects:

[0019] By combining frequency conversion performance with mobility into the cable, the problem of frequency conversion cables being unable to be used in mobile applications is solved, improving energy efficiency. Special conductor materials allow the conductor to undergo multiple bends and movements without deformation or burrs, and without damaging the insulation layer. Ethylene propylene rubber is used as the insulation material to improve insulation flexibility, while polyurethane is used for both the inner and outer sheaths, offering excellent strength and abrasion resistance. Simultaneously, the braided shielding layer uses metal-composite aramid fiber braiding to reduce the risk of broken wires puncturing the inner sheath and damaging the insulation layer during cable movement. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments;

[0021] Figure 1 This is a cross-sectional structural schematic diagram of the present invention;

[0022] In the diagram: 11. Power conductor; 12. Power insulation layer; 21. Ground conductor; 22. Ground insulation layer; 3. First isolation layer; 4. Inner sheath; 5. Shielding layer; 6. Braided shielding layer; 7. Second isolation layer; 8. Outer sheath. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of the embodiments of this utility model will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some, but not all, embodiments of this utility model. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0024] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this utility model. The embodiments of this utility model will be described in detail below with reference to the accompanying drawings.

[0025] It should be understood that the accompanying drawings are for illustrative purposes only.

[0026] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. These drawings are simplified schematic diagrams, which are only used to illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.

[0027] A variable frequency mobile cable for ships and offshore platforms, such as Figure 1 As shown, it includes a cable core, an inner sheath 4, a braided shielding layer 6, and an outer sheath 8 arranged in sequence.

[0028] The cable core includes a conductor, an insulation layer disposed on the outside of the conductor, and a reinforcing nonwoven fabric wrapped between the conductor and the insulation layer. The cable core is provided with a power unit and a ground unit twisted together. The power unit includes a power conductor 11, a power insulation layer 12 extruded on the outside of the power conductor 11, and a power reinforcing nonwoven fabric wrapped between the power conductor 11 and the power insulation layer 12. The ground unit includes a ground conductor 21, a ground insulation layer 22 extruded on the outside of the ground conductor 21, and a ground reinforcing nonwoven fabric wrapped between the ground conductor 21 and the ground insulation layer 22.

[0029] The power conductor 11 and the ground conductor 21 are made of the same material, both being tin-plated Class 5 flexural tin-plated copper conductors. This ensures that during cable dynamic operation, the breakage of a single conductor filament will not puncture the insulation layer. The nominal diameter of each filament is set to 0.25-0.50 mm, and the elongation at break is greater than or equal to 20%. The filaments are arranged in a multi-strand strand configuration. Several filament bundles are combined into a single strand, and several strands are then twisted together to form a conductor. The filament bundles are bundled to the left, with a bundle pitch ratio of 20-25. The twisting direction is also to the left, with a twist pitch ratio of 15-20 for the inner layer and 10-12 for the outermost layer. Both the monofilament bundle and the stranded wires are twisted in the left direction. This consistent direction enhances stability and helps the conductor maintain a more uniform structure and performance during bending and twisting, reducing uneven internal stress distribution caused by inconsistent twisting directions. It also improves fatigue resistance, reducing fatigue damage to the conductor during repeated bending and twisting, and extending the conductor's service life. Furthermore, it reduces internal friction, as the consistent twisting direction reduces friction between the conductor's internal cores during bending and twisting, thus reducing wear and heat generation.

[0030] A layer of power-reinforced nonwoven fabric is overlapped and wrapped around the power conductor 11, and a layer of ground-reinforced nonwoven fabric is overlapped and wrapped around the ground conductor 21. The overlap probability is 25%-30%. The reinforced nonwoven fabric can equalize the electric field and eliminate the tip discharge on the conductor surface.

[0031] Both the power insulation layer 12 and the ground insulation layer 22 are extruded using a rubber extruder with a screw diameter of φ70mm-φ120mm and a length-to-diameter ratio of 16:1. The materials of both the power insulation layer 12 and the ground insulation layer 22 are ethylene propylene insulation material with a temperature resistance rating of -40℃ to 80℃. Ethylene propylene insulation material has high electrical insulation performance and excellent flexibility. After extrusion, the insulation is vulcanized by high-pressure steam at a pressure of 1.2MPa-1.5MPa. After high-pressure steam vulcanization, the ethylene propylene rubber is tightly bonded to the surface of the reinforced non-woven fabric. When the cable moves at high speed, the insulation layer, the reinforced non-woven fabric, and the conductor will not shift.

[0032] The power unit and ground wire unit are cabled together using a stranding machine. Before production, the tension during take-up and release is adjusted to ensure uniform tension during production. The cable formation direction is left-handed, the cable pitch ratio is less than or equal to 9, and the cable formation direction is the same as the conductor stranding direction. This helps maintain the cable's structural stability, making it less prone to structural deformation under bending and tension conditions. Simultaneously, the same stranding direction reduces relative movement and friction between conductors and between conductors and insulation layers, reducing wear and extending the cable's service life. It also improves electromagnetic compatibility, reducing electromagnetic interference and radiation generated inside the cable.

[0033] Furthermore, three power units and three ground wire units are provided. The three ground wire units are located outside the power units. Each power unit is tangentially arranged with the other two power units, and each ground wire unit is tangentially arranged with two power units evenly, thereby reducing the cable size and preventing cable core breakage.

[0034] An inner sheath 4 is provided on the outside of the cable core. The inner sheath 4 is extruded using a screw with a screw diameter of φ90mm-φ120mm and a length-to-diameter ratio of 25:1. The material of the inner sheath 4 is polyurethane, specifically thermoplastic polyurethane (TPU) with a temperature resistance of -40℃ to 80℃, a tear strength ≥40N / mm, and an original mechanical property ≥20MPa. This gives the inner sheath 4 excellent strength, preventing broken wires of the shielding layer 5 located on the outside of the inner sheath 4 from puncturing the power insulation layer 12 and / or the ground insulation layer 22, thus preventing cable failure. Simultaneously, the extrusion pressure is increased during the extrusion of the inner sheath 4 to ensure a tight fit between the inner sheath 4 and the cable core.

[0035] A shielding layer 5 is wrapped between the inner sheath 4 and the braided shielding layer 6. The shielding layer 5 is a copper-plastic composite strip. The copper-plastic composite strip is wrapped around the surface of the inner sheath 4. The copper-plastic composite strip includes a copper side and a plastic side. The copper side of the copper-plastic composite strip faces the braided shielding layer 6 and forms electrical contact with the braided shielding layer 6. The overlap rate is ≥25%.

[0036] The braided shielding layer 6 is made of composite aramid fiber, more specifically, the composite aramid fiber is made of metal composite aramid fiber. The metal composite aramid fiber is woven to form the braided shielding layer 5. The metal composite aramid fiber includes aramid fiber and tin-plated copper wound on the aramid fiber. The tin-plated copper is annealed and flattened and then wound on 400D aramid fiber. According to the shielding requirements, it is wound 12 turns every 10mm. The single bundle resistance is less than 2.5Ω / m, the diameter is less than 0.27mm, and it can withstand a tensile force of 15N. Taking a cable with an outer diameter of 10mm as an example, a braided shielding layer 6 with a braiding density of 90% is woven on it. Four metal composite aramid fibers are stranded together and woven by a 24-spindle braiding machine. When the whole is under stress, it can withstand a tensile force of 1440N. Since the tin-plated copper is spirally wound on the aramid fiber, when the aramid fiber is under stress, the tin-plated copper is not under stress, avoiding the breakage caused by the thin diameter and low tensile strength of the tin-plated copper wire.

[0037] The combined use of the shielding layer 5 and the braided shielding layer 6 can enhance tensile strength and prevent the copper wires from being broken during operation, which would cause the inner sheath 4 and the cable core to be punctured, thus improving the service life of the cable.

[0038] A first isolation layer 3 is provided between the cable core and the inner sheath 4, and a second isolation layer 7 is provided between the braided shielding layer 6 and the outer sheath 8.

[0039] The outer sheath 8 is extruded using a screw with a screw diameter of φ90mm-φ120mm and a length-to-diameter ratio of 25:1. The outer sheath 8 and the inner sheath 4 are made of the same material, polyurethane. Furthermore, the material of the outer sheath 8 is thermoplastic polyurethane (TPU), with a temperature resistance of -40℃ to 80℃, a tear strength greater than or equal to 40N / mm, and an original mechanical property greater than or equal to 20MPa. This gives the outer sheath 8 excellent strength, preventing the shielding layer 5 from breaking and puncturing the outer sheath 8, thus preventing cable failure.

[0040] This utility model solves the defects existing in the background technology, and has the following beneficial effects:

[0041] By combining frequency conversion performance with mobility into the cable, the problem of frequency conversion cables being unable to be used in mobile applications is solved, improving energy efficiency. Special conductor materials allow the conductor to undergo multiple bends and movements without deformation or burrs, and without damaging the insulation layer. Ethylene propylene rubber is used as the insulation material to improve insulation flexibility. A special cabling pitch ratio gives the cable excellent bending and mobility performance. The inner sheath 4 and outer sheath 8 are made of polyurethane, which has excellent strength and wear resistance. Meanwhile, the braided shielding layer 6 uses metal composite aramid fiber braiding to reduce the risk of broken wires puncturing the inner sheath 4 and damaging the insulation layer during cable movement. When the cable core cabling direction is the same as the conductor stranding direction, the magnetic field distribution inside the cable is more uniform. From an electromagnetic perspective, current passing through a conductor generates a magnetic field. If the cabling direction is consistent with the conductor stranding direction, the magnetic fields generated by each conductor are superimposed in a relatively stable and orderly manner, making it difficult for external electromagnetic interference to enter the cable and for internal electromagnetic signals to radiate outwards, thus reducing electromagnetic interference to a certain extent.

[0042] Based on the preferred embodiments of this utility model described above, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined according to the scope of the claims.

[0043] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0044] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable way without contradiction. In order to avoid unnecessary repetition, this utility model will not describe the various possible combinations separately.

[0045] Furthermore, various different embodiments of this utility model can be combined in any way, as long as they do not violate the spirit of this utility model, they should also be regarded as the content disclosed by this utility model.

Claims

1. A variable frequency mobile cable for ships and offshore platforms, characterized in that: The cable includes a cable core, an inner sheath (4), a braided shielding layer (6), and an outer sheath (8) arranged in sequence. The cable core includes a conductor and an insulation layer disposed on the outside of the conductor. The conductor is a tin-plated copper conductor of type 5, and the insulation layer is ethylene propylene rubber. The inner sheath (4) and the outer sheath (8) are made of polyurethane, and the braided shielding layer (6) is made of composite aramid fiber.

2. The variable frequency mobile cable for ships and offshore platforms according to claim 1, characterized in that: The conductor comprises several tin-plated copper monofilaments, which are bundled together in the same direction to form a strand, and the strands are twisted together in the same direction to form a conductor. The direction of the cable core is the same as the direction of the twisting.

3. The variable frequency mobile cable for ships and offshore platforms according to claim 2, characterized in that: The bundle pitch ratio of the tin-plated copper monofilament is 20-25 times; the twisted pitch ratio of the inner strands is 15-20 times, and the twisted pitch ratio of the outermost strands is 10-12 times; the cabling pitch ratio of the cable core is less than or equal to 9 times.

4. The variable frequency mobile cable for ships and offshore platforms according to claim 1, characterized in that: The composite aramid fiber includes aramid fibers and tin-plated copper wound around the aramid fibers.

5. The variable frequency mobile cable for ships and offshore platforms according to claim 1, characterized in that: A reinforcing nonwoven fabric is wrapped between the conductor and the insulating layer.

6. The variable frequency mobile cable for ships and offshore platforms according to claim 1, characterized in that: A shielding layer (5) is provided between the inner sheath (4) and the braided shielding layer (6).

7. The variable frequency mobile cable for ships and offshore platforms according to claim 6, characterized in that: The shielding layer (5) is configured as a copper-plastic composite strip, which includes a copper surface and a plastic surface, with the copper surface of the copper-plastic composite strip facing the side of the braided shielding layer (6).

8. The frequency conversion mobile cable for ships and offshore platforms according to claim 1, characterized in that: A first isolation layer (3) is provided between the cable core and the inner sheath (4), and a second isolation layer (7) is provided between the braided shielding layer (6) and the outer sheath (8).

9. The variable frequency mobile cable for ships and offshore platforms according to claim 1, characterized in that: The cable core is provided with a power unit and a ground unit twisted together. The power unit includes a power conductor (11) and a power insulation layer (12) extruded outside the power conductor (11). The ground unit includes a ground conductor (21) and a ground insulation layer (22) extruded outside the ground conductor (21).

10. The variable frequency mobile cable for ships and offshore platforms according to claim 9, characterized in that: The power unit is provided in three parts, and the ground wire unit is provided in three parts. The three ground wire units are located outside the power unit. Each power unit is tangent to the other two power units, and each ground wire unit is tangent to the other two power units.

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