Water-spray-resistant and knock-resistant fire-resistant power cable for nuclear power station
By using low-smoke, halogen-free, high-fire-retardant shell-type filler in the refractory cables for nuclear power plants, the problem of short-circuiting conductors in the fire sprinkler system for nuclear power plants is solved, and the cable is in flame conditions are realized Normal power-on and water resistance under the condition.
Patent Information
- Application Number
- CN202420345131.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-02-24
- Publication Date
- 2024-12-20
- Estimated Expiration
- 2034-02-24
AI Technical Summary
After the fire sprinkler system is started, water sprayed onto the cable, causing a short circuit of the conductor, affecting personnel escape and equipment repair.
Low-smoke, halogen-free, high flame retardant shell-type filler is used to cover the cable core by extrusion and extrusion, forming a tightly bonded filler layer to reduce the presence of air, prevent the flame from spreading, and not damaged in the insulating layer and mica layer. In the case of maintaining insulation characteristics to ensure normal power on the cable.
After the fire sprinkler system is started, the cable can still maintain normal power supply, reduce the combustion of internal insulated wire cores, ensure the use of fire-resistant cables, and improve the fire resistance and waterproof performance of the cable.
Smart Images
Figure CN222213783U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of cables, and in particular to a fire-resistant power cable for use in nuclear power plants that is resistant to water spraying and impact. Background Art
[0002] Due to the occurrence of many large-scale fire accidents in recent years, people have paid more and more attention to fire safety and the safety of electricity use in fires. Therefore, the cables used in places and equipment related to fire safety and fire rescue are all fire-resistant cables.
[0003] The main function of fire-resistant cables is to maintain the power-on state for a certain period of time during a fire, provide power for the startup and normal operation of fire-fighting equipment, and provide time for personnel to escape and equipment to repair. It plays an important role in the fire process.
[0004] Considering the particularity of nuclear power plants, fire-resistant cables used in nuclear power plants are required to have not only good fire resistance but also high comprehensive performance requirements, especially in terms of electrical performance, mechanical performance, flame retardancy, low smoke and halogen-free performance, flexibility, knock resistance and service life. Therefore, fire-resistant cables used in nuclear power plants are generally mica tape wrapped fire-resistant cables.
[0005] The existing mica tape wrapped fire-resistant cables for nuclear power plants on the market can only meet the fire resistance requirements of simple fire supply or fire supply plus impact vibration. Once the fire sprinkler system is activated, water will spray onto the cable, causing a short circuit between the cable conductors, causing power outages in the equipment, affecting personnel escape and equipment repairs. Utility Model Content
[0006] In order to ensure the normal use of fire-resistant cables after the fire sprinkler system is activated, the present application provides a fire-resistant power cable for nuclear power plants that is resistant to water spraying and impact.
[0007] The present application provides a fire-resistant power cable for nuclear power plants that is resistant to water spraying and knocking, which adopts the following technical solution:
[0008] A fire-resistant power cable for nuclear power plants that is resistant to water spraying and knocking, comprising a cable core and a filling layer and an outer sheath sequentially coated on the cable core from the inside to the outside;
[0009] The cable core is composed of a plurality of insulated wire cores twisted together, wherein the insulated wire core comprises a conductor and a mica layer and an insulating layer sequentially coated on the conductor from the inside to the outside;
[0010] The filling layer is formed by extruding a low-smoke, halogen-free and highly flame-retardant crust-type filling material.
[0011] By adopting the above technical solution, the low-smoke halogen-free and highly flame-retardant encrusting filler is extruded outside the cable core by extrusion. The low-smoke halogen-free and highly flame-retardant encrusting filler is completely embedded in the gap of the cable core under the action of the extrusion force, and the cable core and the filling layer are tightly combined, thereby reducing the presence of air between the cable core and the filling layer. In addition, the filling layer formed by the extrusion of the low-smoke halogen-free and highly flame-retardant encrusting filler has a crusting property after combustion, thereby forming a protective shell around the cable core, preventing the internal cable core from contacting the air and preventing the flame from spreading to the inside of the cable, which can reduce the probability of burning the internal insulation core, thereby ensuring the integrity of the insulation layer and the mica layer. Even if the fire sprinkler water is sprayed onto the surface of the cable, since the insulation layer and the mica layer are not damaged, the insulation characteristics can still be maintained, and the cable can still maintain normal power supply, thereby ensuring that the fire-resistant cable is normally powered after the fire sprinkler system is started.
[0012] Optionally, the filling layer has a thickness of 2 mm.
[0013] Optionally, the conductor is formed by twisting multiple strands of soft round copper wires and the twisting pitch ratio ranges from 15 to 20, and the conductor cross-section ranges from 1.5 mm 2 ~6mm 2 .
[0014] By adopting the above technical solution, the conductor with a twisted structure is more flexible than the conductor with a solid structure, and is more conducive to the bending performance of the cable.
[0015] Optionally, the mica layer is formed by overlapping and wrapping three layers of calcined mica tapes, and the overlapping rate of the mica layer wrapping is not less than 50%.
[0016] By adopting the above technical solution, the mica layer in the mica tape is an inorganic substance and does not burn under flame conditions, thereby ensuring that the conductors can still maintain an insulation state under flame conditions to ensure that the cable can be energized normally.
[0017] Optionally, the insulating layer includes an inner insulating layer and an outer insulating layer coated on the inner insulating layer, the inner insulating layer is made of radiation cross-linked polyethylene material, and the outer insulating layer is made of flame-retardant radiation cross-linked polyolefin material.
[0018] By adopting the above technical solution, the radiation cross-linked polyethylene material has the characteristics of high electrical performance and high mechanical performance. The flame retardant radiation cross-linked polyolefin can be used to ensure the flame retardant performance of the insulating core.
[0019] Optionally, the inner insulating layer and the outer insulating layer are formed by a double-layer co-extrusion extrusion process.
[0020] By adopting the above technical solution and a double-layer co-extrusion extrusion process, it is ensured that the materials of the inner insulating layer and the outer insulating layer can be completely combined together, thereby improving the bonding tightness of the insulating layer and reducing gaps where air is retained.
[0021] Optionally, the cable core is formed by twisting 2 to 5 insulated wire cores and the twisting pitch ratio ranges from 15 to 20.
[0022] By adopting the above technical solution, the cable core is formed by twisting a plurality of insulating wire cores, thereby ensuring the flexibility and bendability of the cable.
[0023] Optionally, a peeling layer is provided between the cable core and the filling layer, and the peeling layer is made of talcum powder material.
[0024] By adopting the above technical solution, talcum powder is used to ensure that the filling layer and the cable core are not adhered to each other, so that the filling layer can be easily peeled off from the cable core, so as to facilitate the installation and use of the insulating core.
[0025] Optionally, the outer sheath is made by extruding a thermoplastic highly flame-retardant polyolefin sheath material.
[0026] By adopting the above technical solution, since the outer sheath is extruded in an extrusion manner, the outer sheath is tightly combined with the filling layer and serves as the first protective layer under flame conditions, thereby preventing the flame from spreading to the inside of the cable.
[0027] Optionally, a waterproof layer is provided between the stripping layer and the filling layer, and the waterproof layer is made of a plastic coating material.
[0028] By adopting the above technical solution, the waterproof layer made of plastic coating material is not only waterproof, which can prevent the insulation layer from failing due to contact with water, but also the plastic coating layer has high flexibility and processability, so as to improve the bending performance of the cable.
[0029] In summary, the present application includes at least one of the following beneficial technical effects:
[0030] 1. The filling layer formed by extruding low-smoke, halogen-free, highly flame-retardant encrusting filler has encrusting properties after burning, forming a protective shell around the cable core to prevent the internal cable core from contacting the air and prevent the flame from spreading into the cable to ensure the integrity of the insulation layer and mica layer. After the fire sprinkler system is activated, the cable can still maintain its insulation properties, thus ensuring the normal use of the fire-resistant cable;
[0031] 2. The low-smoke, halogen-free, highly flame-retardant encrusting filler is extruded outside the cable core in an extrusion manner, so that the material is completely embedded in the gap at the edge of the cable core, and the cable core and the material are tightly combined, thereby reducing the presence of air between the cable core and the cable core, and reducing the probability of burning of the material inside the cable core;
[0032] 3. The mica layer in the mica tape is an inorganic substance and does not burn under flame conditions. This ensures that the conductors can still maintain insulation under flame conditions to ensure that the cable can be powered normally. BRIEF DESCRIPTION OF THE DRAWINGS
[0033] Figure 1 It is a schematic diagram of the radial cross-section of the fire-resistant power cable in Example 1 of the present application.
[0034] Figure 2 It is a schematic diagram of the radial cross-section of the fire-resistant power cable in Example 2 of the present application.
[0035] Description of reference numerals:
[0036] 1. Cable core; 11. Insulated core; 111. Conductor; 112. Mica layer; 113. Inner insulating layer; 114. Outer insulating layer; 2. Filling layer; 3. Outer sheath; 4. Stripping layer; 5. Waterproof layer. DETAILED DESCRIPTION
[0037] The following is combined with Figure 1-2 This application is described in further detail.
[0038] It should be noted that, in the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicating orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply 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 understood as a limitation on the present invention.
[0039] Example 1
[0040] Embodiment 1 of the present application discloses a fire-resistant power cable for use in nuclear power plants that is resistant to water spraying and impact.
[0041] Reference Figure 1 The fire-resistant power cable comprises a cable core 1 and a filling layer 2 and an outer sheath 3 sequentially coated on the cable core 1 from the inside to the outside. The cable core 1 is composed of a plurality of insulated cores 11 twisted together, and the insulated core 11 comprises a conductor 111 and a mica layer 112 and an insulating layer sequentially coated on the conductor 111 from the inside to the outside.
[0042] The conductor 111 is made of multiple strands of soft round copper wires twisted together, and the twisting pitch ratio ranges from 15 to 20. The cross-section range of the conductor 111 is 1.5mm 2 ~6mm 2Compared with the conductor 111 of a solid structure, the conductor 111 of the present application adopts a twisted structure and is more flexible, thereby ensuring the bending performance of the cable.
[0043] Secondly, the mica layer 112 is formed by overlapping and wrapping three layers of calcined mica tapes, and the wrapping overlap rate of the mica layer 112 is not less than 50%. Since the mica layer 112 in the mica tape is an inorganic substance, it does not burn under flame conditions. Therefore, under flame conditions, the conductors 111 can still maintain an insulation state to ensure that the cable can be normally energized.
[0044] In addition, the insulating layer includes an inner insulating layer 113 and an outer insulating layer 114 coated on the inner insulating layer 113. The inner insulating layer 113 is made of radiation cross-linked polyethylene material, and the outer insulating layer 114 is made of flame-retardant radiation cross-linked polyolefin material. The radiation cross-linked polyethylene material has the characteristics of high electrical properties and high mechanical properties, and the flame-retardant radiation cross-linked polyolefin can ensure the flame retardant properties of the insulating core 11, so that the insulating layer has high electrical properties, high mechanical properties, and is resistant to knocking while also being flame retardant. The inner insulating layer 113 and the outer insulating layer 114 are formed by a double-layer co-extrusion extrusion process to ensure that the materials of the inner insulating layer 113 and the outer insulating layer 114 can be completely combined together.
[0045] In order to ensure that the cable can still be used normally after the fire sprinkler device is activated, the filling layer 2 is extruded from a low-smoke, halogen-free, highly flame-retardant crust-type filling material, and the thickness of the filling layer 2 is 2 mm.
[0046] The low-smoke, halogen-free, highly flame-retardant encrusting filler is extruded and wrapped outside the cable core 1 by extrusion, so that the material is completely embedded in the edge gap of the cable core 1, and the cable core 1 and the filling layer 2 are tightly combined, thereby reducing the presence of air between the cable core 1 and the filling layer 2. In addition, the low-smoke, halogen-free, highly flame-retardant encrusting filler has encrusting properties after combustion, forming a protective shell around the cable core 1, further preventing the internal cable core 1 from contacting the air and preventing the flame from spreading to the inside of the cable. The insulation layer and the mica layer 112 are still intact. Even if the fire sprinkler water is sprayed onto the surface of the cable, since the insulation layer and the mica layer 112 are not damaged, the insulation properties can still be maintained, and the cable maintains normal power supply.
[0047] In order to further improve the flexibility and bendability of the cable and facilitate subsequent installation, the cable core 1 is formed by twisting 2 to 5 insulated wire cores 11 and the twisting pitch ratio ranges from 15 to 20.
[0048] A peeling layer 4 is provided between the cable core 1 and the filling layer 2. The peeling layer 4 is made of talcum powder material to ensure that the filling layer 2 and the cable core 1 are not adhered to each other, so that the filling layer 2 is easy to be peeled off from the cable core 1, which is convenient for the installation and use of the insulating core 11.
[0049] The outer sheath 3 is made of thermoplastic highly flame-retardant polyolefin sheath material by extrusion, so that the outer sheath 3 is tightly combined with the filling layer 2 and serves as the first protective layer under flame conditions, thereby preventing the flame from spreading to the inside of the cable.
[0050] The implementation principle of the fire-resistant power cable for nuclear power plants that is resistant to water spraying and knocking in the embodiment of the present application is as follows: a low-smoke, halogen-free, highly flame-retardant encrusting filler is extruded and wrapped outside the cable core 1 by an extrusion method, so that the material is completely embedded in the edge gap of the cable core 1, and the cable core 1 and the filling layer 2 are tightly combined, thereby reducing the presence of air between the cable core 1 and the filling layer 2. When a fire occurs, the filling layer 2 has a crusting property after burning, thereby reducing the probability of burning of the internal insulating core 11, thereby ensuring that the cable is normally energized under flame conditions. When the fire sprinkler water is sprayed onto the surface of the cable, since the insulation layer and the mica layer 112 are not damaged, the insulation properties can still be maintained, and the cable can still maintain normal power supply, thereby ensuring the normal use of the fire-resistant cable after the fire sprinkler system is started.
[0051] Example 2
[0052] The difference between Example 2 of the present application and Example 1 is that, referring to Figure 2 The fire-resistant power cable further comprises a waterproof layer 5, which is located between the stripping layer 4 and the filling layer 2 and is coated on the stripping layer 4. The waterproof layer 5 is made of a plastic coating material, which may be polyethylene or polypropylene.
[0053] Since the filling layer 2 can form a protective film after burning and crusting, in order to further waterproof the insulating layer, a waterproof layer 5 is set between the stripping layer 4 and the filling layer 2. The plastic coating material is used, so that the waterproof layer 5 is not only waterproof, but also can prevent the insulating layer from failing due to contact with water. At the same time, the plastic coating layer has high flexibility and processability, so as to improve the bending performance of the cable.
[0054] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.
Claims
1. A fire-resistant power cable for nuclear power plants that is resistant to water spraying and knocking, characterized in that: It comprises a cable core (1), and a filling layer (2) and an outer sheath (3) which are sequentially coated on the cable core (1) from the inside to the outside; The cable core (1) is composed of a plurality of insulated wire cores (11) twisted together, wherein the insulated wire core (11) comprises a conductor (111) and a mica layer (112) and an insulating layer sequentially covering the conductor (111) from the inside to the outside; The filling layer (2) is formed by extruding a low-smoke, halogen-free, highly flame-retardant crust-type filling material.
2. A fire-resistant power cable for nuclear power plants that is resistant to water spraying and knocking according to claim 1, characterized in that: The filling layer (2) has a thickness of 2 mm.
3. The fire-resistant power cable for nuclear power plants that is resistant to water spraying and knocking according to claim 1 is characterized in that: The conductor (111) is formed by twisting a plurality of soft round copper wires, and the twisting pitch ratio is in the range of 15 to 20. The cross section of the conductor (111) is in the range of 1.5 mm 2 ~6mm 2 .
4. The fire-resistant power cable for nuclear power plants that is resistant to water spraying and knocking according to claim 1 is characterized in that: The mica layer (112) is formed by overlapping and wrapping three layers of calcined mica tapes, and the wrapping overlap rate of the mica layer (112) is not less than 50%.
5. The fire-resistant power cable for nuclear power plants that is resistant to water spraying and knocking according to claim 1 is characterized in that: The insulating layer comprises an inner insulating layer (113) and an outer insulating layer (114) coated on the inner insulating layer (113); the inner insulating layer (113) is made of radiation cross-linked polyethylene material, and the outer insulating layer (114) is made of flame-retardant radiation cross-linked polyolefin material.
6. The fire-resistant power cable for nuclear power plants that is resistant to water spraying and knocking according to claim 1, characterized in that: The cable core (1) is formed by twisting 2 to 5 insulating wire cores (11) and the twisting pitch ratio ranges from 15 to 20.
7. The fire-resistant power cable for nuclear power plants that is resistant to water spraying and knocking according to claim 1 is characterized by: A peeling layer (4) is provided between the cable core (1) and the filling layer (2), and the peeling layer (4) is made of talcum powder material.
8. The fire-resistant power cable for nuclear power plants that is resistant to water spraying and knocking according to claim 1 is characterized by: The outer sheath (3) is made by extrusion of a thermoplastic highly flame-retardant polyolefin sheath material.
9. A fire-resistant power cable for nuclear power plants that is resistant to water spraying and knocking according to claim 7, characterized in that: A waterproof layer (5) is provided between the peeling layer (4) and the filling layer (2), and the waterproof layer (5) is made of a plastic coating material.