Medium-voltage fire-resistant cable for maritime work

Abstract

The utility model discloses a medium-voltage fire-resistant cable for maritime work, which comprises a conductor, a conductor shielding layer is extruded on the periphery of the conductor, an insulating layer is extruded on the periphery of the conductor shielding layer, and an insulating shielding layer is extruded on the periphery of the insulating layer to form an insulating wire core; a metal shield is braided at the periphery of the insulating wire core to form a wire core unit, a plurality of wire core units are twisted to form a cable core, a heat insulation layer is extruded at the periphery of the cable core, an armor layer is braided at the periphery of the heat insulation layer, and an outer sheath is crosslinked at the periphery of the armor layer; the insulating layer is made of high-temperature-resistant medium-voltage ethylene propylene rubber, and the heat insulating layer is made of ceramic polyolefin; according to the scheme, high-temperature-resistant ethylene propylene rubber is adopted for insulation of the cable, so that the cable has excellent insulation and heat resistance; the heat insulation layer is made of ceramic polyolefin, the ceramic polyolefin can form a tight heat insulation layer at the temperature above 500 DEG C, heat is effectively isolated outside the cable core, insulation completeness is guaranteed, and normal electric energy transmission in the case of fire disasters is achieved.

Description

Technical Field

[0001] The utility model relates to a cable structure, in particular to a medium-voltage fire-resistant cable for marine engineering. Background Art

[0002] With the continuous increase in the design tonnage of ships and offshore platforms, their power consumption also increases accordingly. In order to meet the requirements of high-power power transmission, the voltage level of the main line cable has been increased from 1.8 / 3 kV and below to 3.6 / 6 kV and above. At the same time, in order to meet the fire protection requirements of ships and offshore platforms, fire-resistant performance requirements are put forward for cables with a rated voltage above 3.6 / 6 kV in special areas.

[0003] Since the voltage level of the fire-resistant cable has been increased from 1.8 / 3 kV and below to 3.6 / 6 kV and above, the conventional mica tape as the cable fire-resistant insulation layer structure can no longer meet the fire-resistant requirements under high voltage.

[0004] In the conventional fire-resistant cable, mica tape is wound around the conductor. After the cable is burned by fire, the polymer material decomposes at high temperature, and the mica tape plays an insulating role. However, for medium-voltage cables with a voltage level above 3.6 / 6 kV, the mica tape cannot withstand the high-voltage electric field. Therefore, it is necessary to study a new fire-resistant structure to meet the fire-resistant requirements of medium-voltage cables. Summary of the Invention

[0005] The utility model overcomes the deficiencies of the prior art and provides a medium-voltage fire-resistant cable for marine engineering.

[0006] To achieve the above object, the technical solution adopted by the utility model is: a medium-voltage fire-resistant cable for marine engineering, including a conductor, an extruded conductor shield layer is arranged on the outer periphery of the conductor, an insulating layer is extruded on the outer periphery of the conductor shield layer, and an insulating shield layer is extruded on the outer periphery of the insulating layer to form an insulated wire core; a metal shield is woven on the outer periphery of the insulated wire core to form a wire core unit, several of the wire core units are stranded to form a cable core, a heat-insulating layer is extruded on the outer periphery of the cable core, an armored layer is woven on the outer periphery of the heat-insulating layer, and a cross-linked outer sheath is arranged on the outer periphery of the armored layer; the insulating layer is made of high-temperature-resistant medium-voltage ethylene propylene rubber, and the heat-insulating layer is made of ceramized polyolefin.

[0007] More specifically, a void is formed inside the cable core, and an expanded glass fiber rope is arranged in the void for filling.

[0008] More specifically, a non-woven tape is wound around the outer periphery of several stranded wire core units.

[0009] More specifically, the thickness of the non-woven fabric is set to 0.2 mm, and the lapping rate is set to 15%-20%.

[0010] More specifically, the conductor is made of galvanized conductor.

[0011] More specifically, the galvanized conductor is arranged as a stranded bundle of a number of galvanized single wires, and the diameter of each galvanized single wire is set to 0.4 mm.

[0012] More specifically, the conductor shielding layer is arranged as a semiconductive conductor shielding layer, and the insulation shielding layer is arranged as a semiconductive insulation shielding layer.

[0013] More specifically, the metal shielding layer is arranged as a braided layer of tinned copper wires, the diameter of the tinned copper wires is set to 0.2 mm, and the braiding density is greater than or equal to 80%.

[0014] More specifically, the armor layer is arranged as a braided armor layer of tinned copper wires, the diameter of the tinned copper wires is set to 0.4 mm, and the braiding density is greater than or equal to 80%.

[0015] More specifically, the outer sheath is arranged as an irradiated cross-linked low-smoke and halogen-free sheath.

[0016] The utility model solves the defects existing in the background art, and the utility model has the following beneficial effects:

[0017] The cable insulation involved in this solution adopts high-temperature resistant ethylene propylene rubber, which has excellent insulation and heat resistance performance; the heat insulation layer material adopts ceramized polyolefin, which can form a tight heat insulation layer above 500 °C, effectively isolating the heat outside the cable core and ensuring the integrity of the insulation to meet the normal power transmission under fire conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The following further describes the utility model in conjunction with the drawings and embodiments;

[0019] Figure 1 is a schematic cross-sectional structure diagram of the utility model;

[0020] In the figure: 1, conductor; 2, conductor shielding layer; 3, insulation layer; 4, insulation shielding layer; 5, metal shielding layer; 6, expanded glass fiber rope filling; 7, non-woven tape; 8, heat insulation layer; 9, armor layer; 10, outer sheath. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] To make the purpose, technical solutions and advantages of the present utility model more clear, the following will describe the technical solutions in the embodiments of the present utility model in more detail with reference to the accompanying drawings in the embodiments of the present utility model. In the drawings, the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions from beginning to end. The described embodiments are part of the embodiments of the present utility model, rather than all of the embodiments. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present utility model, and should not be construed as a limitation to the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts belong to the scope of protection of the present utility model.

[0022] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the scope of protection of the present utility model. The following will explain the embodiments of the present utility model in detail with reference to the drawings.

[0023] It should be understood that the drawings are only used for exemplary illustration of the present application.

[0024] Now, the present utility model will be further described in detail with reference to the drawings and embodiments. These drawings are all simplified schematic diagrams, which only illustrate the basic structure of the present utility model in a schematic manner, and therefore only show the components related to the present utility model.

[0025] A medium-voltage fire-resistant cable for marine engineering, as Figure 1 shown, includes a conductor 1. An extruded conductor shielding layer 2 is provided on the outer periphery of the conductor 1. An insulating layer 3 is extruded on the outer periphery of the conductor shielding layer 2. An insulating shielding layer 4 is extruded on the outer periphery of the insulating layer 3 to form an insulated wire core. A metal shielding layer 5 is woven on the outer periphery of the insulated wire core to form a wire core unit. A plurality of the wire core units are stranded into a cable core. While a plurality of the wire core units are being stranded, a non-woven tape 7 is wound around. An expanded glass fiber rope filler 6 is provided in the voids of the cable core. A heat-insulating layer 8 is extruded on the outer periphery of the cable core. An armor layer 9 is woven on the outer periphery of the heat-insulating layer 8. A cross-linked outer sheath 10 is provided on the outer periphery of the armor layer 9.

[0026] The conductor 1 is the 5th type of tinned conductor specified by the IEC 60228 standard, which is stranded by a number of tinned single wires. The diameter of each tinned single wire is the same. The diameter of the galvanized single wire is set as required, but the diameter of the tinned single wire is not less than 0.4 mm. The 5th type of tinned conductor has good flexibility, and the finished cable produced with it is easy to bend, which can reduce the difficulty of cable installation and laying and reduce the possibility of cable breakage.

[0027] The outer circumference of the conductor 1 is simultaneously extruded with a conductor shield layer 2, an insulating layer 3, and an insulation shield layer 4 by a 150 + 100 + 60 three-layer co-extrusion continuous vulcanization production line to form an insulated wire core. The conductor shield layer 2 is set as a semi-conductive conductor shield layer, the insulation shield layer 4 is set as a semi-conductive insulation shield layer, and the material of the insulating layer 3 is a high-temperature resistant medium-voltage ethylene propylene rubber, and the high-temperature resistant medium-voltage ethylene propylene rubber material has certain insulation performance below 250 °C.

[0028] The metal shield layer 5 is set as a tinned copper wire braid, and the metal shield layer 5 is braided around the outer circumference of the insulated wire core to form a cable core. A number of tinned copper wires are provided, and the diameters of the number of tinned copper wires are the same. The diameter of each tinned copper wire is set to 0.2 mm, and the braiding density of the number of tinned copper wires is greater than or equal to 80%.

[0029] The cable core is set to be stranded by a number of insulated wire cores. More specifically, the cable core is set to be stranded by three insulated wire cores. During the stranding process of the three insulated cable cores, a layer of non-woven tape 7 is wrapped around the outer circumference of the three insulated cable cores. The thickness of the non-woven fabric is set to 0.2 mm, and the lapping rate is set to 15% - 20%. A void will be formed in the middle of the stranded cable core. If the void is retained, it will affect the strength and fire resistance of the cable, and at the same time, it is easy to be extruded and deformed, resulting in the phenomenon of uniform breakdown of the electric field. Therefore, an expanded glass fiber rope filler 6 is provided in the void. Of course, ordinary glass fiber ropes can also be filled in the void, but it may cause the glass fiber to prick the hand during use. Therefore, in this solution, the glass fiber rope provided is an expanded glass fiber rope after expansion treatment, and the preparation of the expanded glass fiber rope mainly includes fiber forming, fiber stranding, and expansion treatment.

[0030] The heat insulation layer 8 is set as a low-smoke and halogen-free ceramifiable polyolefin material, and the low-smoke and halogen-free ceramifiable polyolefin material is produced by extrusion using an extruder.

[0031] The armor layer 9 is set as a tinned copper wire braided armor layer. A number of tinned copper wires are provided, and the diameters of the number of tinned copper wires are the same. The diameter of each tinned copper wire is set to 0.4 mm, and the braiding density is greater than or equal to 80%.

[0032] The outer sheath 10 is set as an irradiated cross-linked low-smoke and halogen-free sheath, and the material of the irradiated cross-linked low-smoke and halogen-free sheath is extruded using an extruder.

[0033] Due to the relatively large outer diameter of medium-voltage cables, electrons are vertically emitted directly above the cable. The molecular chains of the sheath are crosslinked under the action of electrons, which results in the sheath directly above the cable being more affected by electrons than the sheath directly below the cable, causing uneven irradiation. To ensure uniform irradiation of the cable, a reflection magnet is installed below the cable. Using a strong magnetic field, the direction of electron movement is changed so that the outer sheath 10 of the cable is uniformly affected by electrons to ensure the performance consistency of the outer sheath 10 of the cable.

[0034] The preparation process of the marine medium-voltage fire-resistant cable is as described below:

[0035] A number of tinned single wires are bunch-stranded into a conductor 1, and then the conductor shield layer 2, the insulation layer 3, and the insulation shield layer 4 are extruded in sequence from near the conductor 1 to far from the conductor 1 through a production line. The conductor shield layer 2 and the insulation shield layer 4 are both made of semi-conductive shielding materials, and the insulation layer 3 is made of high-temperature-resistant ethylene propylene rubber material to ensure the fire-resistant performance of the cable. The conductor 1, the conductor 1 shield layer, the insulation layer 3, and the insulation shield layer 4 are closely attached to each other to form an insulated wire core.

[0036] A metal shield layer 5 is braided around the outer periphery of the insulated wire core to form a wire core unit. The metal shield layer 5 is made of tinned copper wire braiding. Then, three wire core units with the same structural performance are stranded to form a cable core. During the stranding process of the three wire core units, a layer of non-woven fabric is wrapped around their outer periphery. After the non-woven fabric wrapping is completed, voids will be formed inside the cable core. To reduce the extrusion deformation of the cable, expanded glass fiber ropes are filled in the voids.

[0037] After the expanded glass fiber ropes are filled, a heat insulation layer 8 is extruded around the cable core. The heat insulation layer 8 is made of low-smoke and halogen-free ceramifiable polyolefin material. After the heat insulation layer 8 is extruded, an armor layer 9 is provided on the outer periphery of the heat insulation layer 8. The armor layer 9 is also made of tinned copper wire braiding, but the diameter of the tinned copper wire of the armor layer 9 is larger than the diameter of the tinned copper wire of the metal shield layer 5. After the armor layer 9 is provided, an outer sheath 10 is extruded on the outer periphery of the armor layer 9. The outer sheath 10 uses an irradiated cross-linked low-smoke and halogen-free outer sheath 10, and a reflection magnet is added during the irradiation cross-linking process to ensure the performance consistency of the outer sheath 10.

[0038] The present invention solves the defects in the background technology and has the following beneficial effects:

[0039] For the insulation layer 3 of the cable involved in this solution, high-temperature resistant ethylene propylene rubber is adopted, which has excellent insulation and heat resistance properties; the filling material is expanded glass fiber rope, which tightly fills the cable core, avoiding the generation of voids due to the decomposition of conventional filling materials at high temperatures, preventing the insulation from deforming under extrusion pressure and avoiding the phenomenon of uniform breakdown of the electric field. At the same time, the glass fiber rope is expanded to soften the texture of the glass fiber, avoiding the problem of glass fiber pricking hands during use; the material of the heat insulation layer 8 is ceramicized polyolefin, which can form a tight heat insulation layer 8 above 500 °C, effectively isolating the heat outside the cable core and ensuring the integrity of the insulation to meet the normal power transmission in case of fire.

[0040] Based on the ideal embodiments of the present invention as inspiration, through the above description, relevant personnel can completely make various changes and modifications without departing from the technical idea of the present invention. The technical scope of the present invention is not limited to the content in the specification, and the technical scope must be determined according to the scope of the claims.

[0041] 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 in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0042] In addition, it should be noted that, in the above specific embodiments, the various specific technical features described can be combined in any appropriate manner without contradiction. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0043] In addition, any combination can be made between different embodiments of the present invention, as long as it does not violate the idea of the present invention, it should also be regarded as the content disclosed by the present invention.

Claims

1. A medium-voltage fire-resistant cable for offshore engineering, characterized in that: It includes a conductor (1), with a conductor shielding layer (2) extruded around the outer circumference of the conductor (1), an insulating layer (3) extruded around the outer circumference of the conductor shielding layer (2), and an insulating shielding layer (4) extruded around the outer circumference of the insulating layer (3) to form an insulated conductor core; a metal shielding layer (5) is woven around the outer circumference of the insulated conductor core to form a conductor core unit, several of the conductor core units are stranded to form a cable core, a heat-insulating layer (8) is extruded around the outer circumference of the cable core, an armor layer (9) is woven around the outer circumference of the heat-insulating layer (8), and a crosslinked outer sheath (10) is provided around the outer circumference of the armor layer (9); the insulating layer (3) is made of high-temperature resistant medium-voltage ethylene propylene rubber, and the heat-insulating layer (8) is made of ceramized polyolefin.

2. The medium-voltage fire-resistant cable for marine engineering according to claim 1, characterized in that: Expanded glass fiber ropes are filled inside the cable core.

3. The medium-voltage fire-resistant cable for marine engineering according to claim 1, characterized in that: A non-woven tape (7) is wound around the outer circumference of the cable core.

4. The medium-voltage fire-resistant cable for marine engineering according to claim 3, characterized in that: The thickness of the non-woven tape (7) is set to 0.2 mm, and the lapping rate is set to 15%-20%.

5. The medium-voltage fire-resistant cable for marine engineering according to claim 1, characterized in that: The conductor (1) is a galvanized conductor.

6. The medium-voltage fire-resistant cable for marine engineering according to claim 5, wherein: The galvanized conductor includes a number of galvanized single wires, and several of the galvanized single wires are stranded to form the galvanized conductor, and the diameter of each galvanized single wire is set to 0.4 mm.

7. The medium-voltage fire-resistant cable for marine engineering according to claim 1, wherein: The conductor shielding layer (2) is a semi-conductive conductor shielding layer, and the insulating shielding layer (4) is a semi-conductive insulating shielding layer.

8. The medium-voltage fire-resistant cable for marine engineering according to claim 1, wherein: The metal shielding layer (5) is a tinned copper wire braided layer, the diameter of the tinned copper wire is set to 0.2 mm, and the braiding density is greater than or equal to 80%.

9. The medium-voltage fire-resistant cable for marine engineering according to claim 1, characterized in that: The armor layer (9) is a tinned copper wire braided armor layer, the diameter of the tinned copper wire is set to 0.4 mm, and the braiding density is greater than or equal to 80%.

10. The medium-voltage fire-resistant cable for marine engineering according to claim 1, characterized in that: The outer sheath (10) is an irradiated crosslinked low-smoke and halogen-free sheath.

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