A single-core medium-voltage flame-retardant and fire-resistant power cable

Abstract

The present invention discloses a single-core medium-voltage flame-retardant and fire-resistant power cable, comprising a conductor, an insulating co-extruded layer coated outside the conductor, and a metal shielding layer coated outside the insulating co-extruded layer, characterized in that a buffer layer is further coated outside the metal shielding layer, a heat insulation layer is coated outside the buffer layer, a composite fire barrier layer is coated outside the heat insulation layer, an armor layer is coated on the composite fire barrier layer, and an outer sheath is coated outside the armor layer. The present invention has good heat insulation and heat dissipation performance and is not prone to mechanical damage to the insulation due to expansion. The present invention can still maintain the ability to conduct electricity for a long time during combustion, providing a certain guarantee for fire rescue and power supply of special equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of power cables, and in particular to a single-core medium-voltage flame-retardant and fire-resistant power cable. Background Art

[0002] With the continuous development of society, people's attention to the safety of cable use is gradually improving, and flame-retardant and fire-resistant cables have received great attention. At the same time, the demand is also gradually increasing. Flame-retardant and fire-resistant cables are mainly used in places where cables are densely laid and densely populated, mainly including high-rise buildings, rail transit lines and stations, large entertainment venues, nuclear power plants, petrochemical sites, tunnels, airports, large industrial and mining enterprises and important underground projects, etc. These places have put forward higher requirements on the flame-retardant and fire-resistant properties of cables. The medium-voltage flame-retardant and fire-resistant power cables currently used in the market are mostly three-core medium-voltage flame-retardant and fire-resistant cables, and single-core medium-voltage flame-retardant and fire-resistant power cables are scarce products. Moreover, the existing single-core medium-voltage flame-retardant and fire-resistant power cables also have the problems of poor thermal insulation and heat dissipation performance, and are prone to mechanical damage to the insulation due to expansion. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a single-core medium-voltage flame-retardant and fire-resistant power cable with good thermal insulation and heat dissipation performance and not prone to mechanical damage to the insulation due to expansion.

[0004] The technical problem to be solved by the present invention can be achieved by the following technical solutions:

[0005] A single-core medium-voltage flame-retardant and fire-resistant power cable comprises a conductor, an insulating co-extruded layer coated outside the conductor, and a metal shielding layer coated outside the insulating co-extruded layer. The cable is characterized in that a buffer layer is coated outside the metal shielding layer, a heat insulation layer is coated outside the buffer layer, a composite fire barrier layer is coated outside the heat insulation layer, an armor layer is coated on the composite fire barrier layer, and an outer sheath is coated outside the armor layer.

[0006] In a preferred embodiment of the present invention, the insulating co-extruded layer is an insulating three-layer co-extruded layer, which is composed of an inner shielding layer, an insulating layer and an outer shielding layer from the inside to the outside.

[0007] In a preferred embodiment of the present invention, the metal shielding layer is formed by wrapping a copper tape.

[0008] In a preferred embodiment of the present invention, the buffer layer is formed by wrapping a fluffy water-blocking wrapping tape.

[0009] In a preferred embodiment of the present invention, the fluffy body water-blocking wrapping tape comprises a glass fiber tape and a buffer tape, wherein the glass fiber tape is wrapped in 2 to 4 layers, and the buffer tape is wrapped in 1 to 2 layers, and the buffer tape is wrapped around the periphery of the glass fiber tape.

[0010] In a preferred embodiment of the present invention, the thermal insulation layer is formed by extrusion or filling of ceramicized polyolefin, ceramicized silicone rubber, ceramicized silicone rubber mud, fireproof mud, fireproof grouting mud or ceramicized silicone rubber tape.

[0011] In a preferred embodiment of the present invention, the composite fire barrier layer is firstly formed by wrapping 2 to 4 layers of glass fiber tape and then wrapping 2 to 10 layers of fire-resistant composite tape.

[0012] In a preferred embodiment of the present invention, the refractory composite belt is composed of a multi-layer combination of a high flame retardant refractory belt and a composite refractory belt, and the high flame retardant refractory belt sandwiches the composite refractory belt inside and outside.

[0013] In a preferred embodiment of the present invention, the armor layer is formed by wrapping a non-magnetic stainless steel strip.

[0014] In a preferred embodiment of the present invention, the outer sheath is extruded from a low-smoke, halogen-free, flame-retardant sheath material.

[0015] Due to the adoption of the above technical solution, the single-core medium-voltage flame-retardant and fire-resistant power cable of the present invention has the following advantages compared with conventional cables:

[0016] 1. The buffer layer of the present invention will be carbonized and form a cavity when the cable is burning or at high temperature, which can alleviate the mechanical damage caused by the expansion of other materials in the cable core to the insulation layer, and can also absorb the water vapor generated by the combustion or high temperature of other materials in the cable core, so as not to affect the ceramic crusting effect of the thermal insulation layer.

[0017] 2. The heat insulation layer of the present invention adopts a ceramic material, which can quickly ceramicize and form a crust under combustion or high temperature conditions, and has a small expansion coefficient, a low crusting temperature and a fast speed. The heat insulation effect after ceramic crusting is very good, and the hard shell does not melt or fall under fire conditions, which can ensure that the insulated wire core will not be damaged due to excessive temperature, thereby reducing or losing the insulation performance.

[0018] 3. The fire barrier layer of the present invention is formed by composite wrapping of glass fiber tape and refractory composite tape, wherein the refractory composite tape is in the form of a multi-layer combination of high flame retardant refractory tape and composite refractory tape. The high flame retardant refractory tape has high strength, and the composite refractory tape is sandwiched inside and outside with high flame retardant refractory tape. Because the composite refractory tape will have a scattering process during the ceramic crusting process, the integrity of the ceramic crust can be ensured after being sandwiched with the high flame retardant refractory tape. The refractory composite tape will present a layer of dense ceramic crust under combustion or high temperature conditions, and this layer has effective fire blocking and heat insulation effects after ceramic crusting.

[0019] 4. The outer sheath is extruded from low-smoke halogen-free flame-retardant sheath material and has good flame retardant properties.

[0020] 5. The present invention can still maintain the ability to be powered for a long time during combustion, providing a certain guarantee for fire rescue and power supply of special equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 It is a structural schematic diagram of a single-core medium-voltage flame-retardant and fire-resistant power cable of the present invention.

[0023] Figure 2 It is a schematic diagram of a radial section of a single-core medium-voltage flame-retardant and fire-resistant power cable of the present invention. DETAILED DESCRIPTION

[0024] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] See also Figure 1 and Figure 2 A single-core medium-voltage flame-retardant and fire-resistant power cable shown in the figure includes a conductor 10, an insulating co-extruded three-layer 20 coated outside the conductor 10, a metal shielding layer 30 coated outside the insulating co-extruded three-layer 20, a buffer layer 40 is coated outside the metal shielding layer 30, a heat insulation layer 50 is coated outside the buffer layer 40, a composite fire barrier layer 60 is coated outside the heat insulation layer 50, an armor layer 70 is coated on the composite fire barrier layer 60, and an outer sheath 80 is coated outside the armor layer 70.

[0026] The present invention is described in detail below by taking WDZBN-YJY63-8.7 / 15Kv-1*70 as an example.

[0027] The conductor 10 has a diameter of 10 mm and is made of copper. The three-layer co-extruded insulation layer is composed of an inner shielding layer, an insulating layer and an outer shielding layer from the inside to the outside. The thickness of the inner shielding layer is 0.8 mm, the material of the insulating layer is cross-linked polyethylene, the thickness is 4.5 mm, and the thickness of the outer shielding layer is 0.6 mm. The metal shielding layer is formed by wrapping a 0.12 mm copper tape.

[0028] The buffer layer 40 is formed by wrapping a fluffy water-blocking wrapping tape. The fluffy water-blocking wrapping tape includes a glass fiber tape and a buffer tape, wherein the glass fiber tape is wrapped in 2 to 4 layers, and the buffer tape is wrapped in 1 to 2 layers, and the buffer tape is wrapped around the periphery of the glass fiber tape. When the cable burns or is subjected to high temperature, the buffer layer will be carbonized and form a cavity, which can alleviate the mechanical damage caused by the expansion of other materials in the cable core to the insulation layer caused by squeezing, and can also absorb the water vapor generated by the combustion of other materials in the cable core or at high temperature, so as not to affect the ceramic crusting effect of the thermal insulation layer.

[0029] The heat insulation layer 50 is extruded from ceramic silicone rubber with a thickness of 2mm-6mm. The composite fire barrier layer is first wrapped with 2 to 4 layers of glass fiber tape, and then wrapped with 2 to 10 layers of refractory composite tape. The refractory composite tape adopts a multi-layer combination of high flame retardant refractory tape and composite refractory tape. The high flame retardant refractory tape has a high strength. The composite refractory tape is sandwiched inside and outside with high flame retardant refractory tape. Because the composite refractory tape will have a scattering process during the ceramic crusting process, the integrity of the ceramic crust can be ensured after being sandwiched with high flame retardant refractory tape. The refractory composite tape will present a dense ceramic crust state under combustion or high temperature conditions. This layer of ceramic crusting has an effective fire barrier and heat insulation effect.

[0030] The armor layer 70 is formed by wrapping a non-magnetic stainless steel strip with a thickness of 0.5 mm. The outer sheath 80 is extruded from a low-smoke, halogen-free, flame-retardant sheath material with a thickness of 2.6 mm.

[0031] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. The present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A single-core medium-voltage flame-retardant and fire-resistant power cable, comprising a conductor, an insulating co-extruded layer wrapped outside the conductor, and a metal shielding layer wrapped outside the insulating co-extruded layer, characterized in that: A buffer layer is coated outside the metal shielding layer, a heat insulation layer is coated outside the buffer layer, a composite fire barrier layer is coated outside the heat insulation layer, an armor layer is coated on the composite fire barrier layer, and an outer sheath is coated outside the armor layer; the buffer layer has the ability to carbonize and form a cavity under combustion or high temperature conditions.

2. The single-core medium-voltage flame-retardant and fire-resistant power cable according to claim 1, characterized in that: The insulating co-extruded layer is an insulating three-layer co-extruded layer, which is composed of an inner shielding layer, an insulating layer and an outer shielding layer from the inside to the outside.

3. The single-core medium-voltage flame-retardant and fire-resistant power cable according to claim 1, characterized in that: The metal shielding layer is formed by wrapping a copper tape.

4. The single-core medium-voltage flame-retardant and fire-resistant power cable according to claim 1, characterized in that: The buffer layer is formed by wrapping a fluffy water-blocking wrapping tape.

5. The single-core medium-voltage flame-retardant and fire-resistant power cable according to claim 4, characterized in that: The fluffy body water-blocking wrapping tape comprises a glass fiber tape and a buffer tape, wherein the glass fiber tape is wrapped in 2 to 4 layers, and the buffer tape is wrapped in 1 to 2 layers, and the buffer tape is wrapped around the periphery of the glass fiber tape.

6. The single-core medium-voltage flame-retardant and fire-resistant power cable according to claim 1, characterized in that: The heat insulation layer is formed by extrusion or filling of ceramic polyolefin, ceramic silicone rubber, ceramic silicone rubber mud, fireproof mud, fireproof grouting mud or ceramic silicone rubber belt.

7. The single-core medium-voltage flame-retardant and fire-resistant power cable according to claim 1, characterized in that: The composite fire barrier layer is firstly formed by wrapping 2 to 4 layers of glass fiber tape and then wrapping 2 to 10 layers of fire-resistant composite tape.

8. The single-core medium-voltage flame-retardant and fire-resistant power cable according to claim 7, characterized in that: The refractory composite belt is composed of a multi-layer combination of a high flame retardant refractory belt and a composite refractory belt, and the high flame retardant refractory belt sandwiches the composite refractory belt inside and outside.

9. The single-core medium-voltage flame-retardant and fire-resistant power cable according to claim 1, characterized in that: The armor layer is formed by wrapping a non-magnetic stainless steel belt.

10. The single-core medium-voltage flame-retardant and fire-resistant power cable according to claim 1, characterized in that: The outer sheath is extruded from low-smoke halogen-free flame-retardant sheath material.

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