A fire-resistant cable

Abstract

The present invention discloses a fire-resistant cable, which includes a conductor. A conductor shielding layer is arranged outside the conductor. An insulating layer is arranged outside the conductor shielding layer. An insulating shielding layer is arranged outside the insulating layer. A semiconductive buffer tape layer is arranged outside the insulating shielding layer. A composite copper tape shielding layer is arranged outside the semiconductive buffer tape layer. The composite copper tape shielding layer includes an inner shaped copper tape winding layer and an outer flat copper tape covering layer. The shaped copper tape winding layer is formed by winding copper tapes with a T-shaped cross-section, and adjacent winding turns overlap a part of each other. There are cavities between the T-shaped copper tapes and both the inner semiconductive buffer tape layer and the outer flat copper tape covering layer, and the cavities are filled with dry powder. The outside of several cable cores is a cable skin, and an insulating filling layer is arranged between the cable skin and the cable cores; through the formation of a composite fire-resistant structure, the cable can achieve the effect of layered heat insulation; the composite copper tape shielding layer forms cavities for accommodating dry powder, which can improve the heat preservation and heat insulation effect.

Description

Technical Field

[0001] The present invention relates to the technical field of cables, and particularly to a fire-resistant cable. Background Art

[0002] With the continuous development of the economy and society, people pay more and more attention to the stability and safety of power use, and the demand for fire-resistant cables further increases. Most traditional medium-voltage fire-resistant cables can operate normally for 90 minutes when the flame temperature is between 700°C and 850°C. However, in actual application scenarios, such as high-rise buildings, subways, large power stations, etc., 90 minutes is not enough to achieve personnel evacuation, fire rescue, and equipment rescue. Therefore, it is necessary to improve the fire-resistant performance of cables and extend the fire-resistant time. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a fire-resistant cable that improves the fire-resistant performance of the cable and extends the fire-resistant time.

[0004] To solve the above technical problem, the present invention includes a plurality of cable cores. Each cable core includes a conductor, with a conductor shielding layer arranged outside the conductor, an insulating layer arranged outside the conductor shielding layer, an insulating shielding layer arranged outside the insulating layer, a semi-conductive buffer tape layer arranged outside the insulating shielding layer, and a composite copper tape shielding layer arranged outside the semi-conductive buffer tape layer. The composite copper tape shielding layer includes an inner special-shaped copper tape winding layer and an outer flat copper tape coating layer. The special-shaped copper tape winding layer is formed by winding a copper tape with a T-shaped cross-section, and adjacent winding circles overlap a part of each other. There are cavities between the T-shaped copper tape and both the inner semi-conductive buffer tape layer and the outer flat copper tape coating layer, and dry powder is filled in the cavities. The outside of the plurality of cable cores is a cable sheath, and an insulating filling layer is provided between the cable sheath and the cable cores.

[0005] One type of cable sheath includes, from the inside to the outside, a first ceramic silicon fire-resistant mica tape layer, an extruded low-smoke and halogen-free polyolefin oxygen isolation layer, a second ceramic silicon fire-resistant mica tape layer, a galvanized steel tape layer, a third ceramic silicon fire-resistant mica tape layer, and an outer sheath.

[0006] Preferably, the conductor shielding layer is extruded from a semi-conductive inner shielding material.

[0007] Further, the insulating layer is extruded from a cross-linked polyethylene material.

[0008] Preferably, the insulating shielding layer is extruded from a semi-conductive outer shielding material.

[0009] In summary, by forming a composite fire-resistant structure, part of the composite structure can generate crystal water and carbon dioxide under flame burning or high-temperature conditions, and form a hard ceramic-like shell, which can achieve the effect of layered heat insulation; the composite copper tape shielding layer can not only reduce electromagnetic interference, ensure the stability of the current transmission process, discharge short-circuit current and play a role in grounding protection, but also form a cavity for accommodating dry powder, which can improve the heat preservation and heat insulation effect, and the external high temperature can be more effectively separated here, further improving the fire resistance performance. And this cable does not generate toxic gases during combustion and releases less smoke during combustion, providing sufficient time for personnel evacuation, fire rescue and equipment rescue. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The present invention will be further described in detail below in conjunction with the drawings and specific embodiments:

[0011] Figure 1 It is a schematic cross-sectional structure diagram of the cable of the present invention;

[0012] Figure 2 is Figure 1 A partial enlarged schematic view of part I of. SPECIFIC EMBODIMENTS

[0013] Referring to the drawings, the fire-resistant cable includes a plurality of cable cores inside. The cable cores include a conductor 1, and a conductor shielding layer 2 is arranged outside the conductor 1. The conductor shielding layer is extruded with a semi-conductive inner shielding material to equalize the electric field at the interface between the conductor and the insulation. An insulation layer 3 is arranged outside the conductor shielding layer. The insulation layer is extruded with a cross-linked polyethylene material and plays a role in insulation and making the current transmit along the direction of the conductor. An insulation shielding layer 4 is arranged outside the insulation layer 3. The insulation shielding layer 4 is extruded with a semi-conductive outer shielding material to equalize the electric field on the outer surface of the insulation and protect the insulation. A semi-conductive buffer tape layer 5 is arranged outside the insulation shielding layer 4 and is made by winding with a winding machine, having a certain flexibility and can absorb the radial expansion of the cable caused by various thermal effects during the operation of the cable. A composite copper tape shielding layer is arranged outside the semi-conductive buffer tape layer 5. The composite copper tape shielding layer includes a special-shaped copper tape winding layer on the inner side and a flat copper tape coating layer 7 on the outer side. The special-shaped copper tape winding layer is wound by a copper tape 6 with a T-shaped cross-section, and adjacent winding circles overlap a part of each other, so that there are cavities 8 between the T-shaped copper tape and the inner semi-conductive buffer tape layer 5 and the outer flat copper tape coating layer 7. The cavities are filled with dry powder. The composite copper tape shielding layer can not only reduce electromagnetic interference, ensure the stability of the current transmission process, discharge short-circuit current and play a role in grounding protection, but also form a cavity for accommodating dry powder, which can improve the heat preservation and heat insulation effect, and the external high temperature can be more effectively separated here, and can also delay the time of burning to the position of the inner conductor during combustion, improving the fire resistance performance; outside the plurality of cable cores is a cable skin, and an insulation filling layer 9 is arranged between the cable skin and the cable cores.

[0014] The insulating filling layer is filled with extruded ceramifiable low-smoke halogen-free polyolefin, extruded by an extruder, and the extrusion filling process is adopted to replace the traditional filling rope filling process, making the cable structure more compact and having a better heat insulation effect. The ceramifiable halogen-free low-smoke flame-retardant filling material is used, which decomposes into water and carbon dioxide when burned or heated at high temperature, does not produce obvious smoke and toxic corrosive gases, absorbs a large amount of heat at the same time, inhibits the temperature rise of the polymer, and generates a hard ceramic-like hard shell. The hard shell does not melt or drip, can resist mechanical vibration, and has a good heat insulation and fire isolation effect, which can effectively isolate the invasion of high-temperature flames into the interior of the cable product, delay the decomposition of internal materials, and ensure the normal operation of the circuit in case of fire.

[0015] The cable skin includes, from the inside to the outside, a first ceramic silicon refractory mica tape layer 10, an extruded low-smoke halogen-free polyolefin oxygen isolation layer 11, a second ceramic silicon refractory mica tape layer 12, a galvanized steel tape layer 13, a third ceramic silicon refractory mica tape layer 13, and an outer sheath 14.

[0016] The ceramic silicon refractory mica tape is made by winding with a winding machine. The ceramic silicon refractory mica tape is an environmentally friendly non-combustible material, which is made by compounding a large amount of synthetic mica powder on the basis of a ceramifiable refractory silicone rubber tape. The fire resistance has a double synergistic effect. When burned or baked, a hard ceramic shell is formed to prevent oxygen from entering the interior and isolate high temperature and heat.

[0017] The extruded low-smoke halogen-free polyolefin oxygen isolation layer is extruded by an extruder, and a ceramifiable halogen-free low-smoke flame-retardant oxygen isolation material is used. Water and carbon dioxide can be decomposed under flame burning or high temperature, and a hard ceramic-like hard shell is generated, thereby isolating high temperature and heat and reducing the heat received by the internal structure.

[0018] The outer sheath is extruded by an extruder, and a halogen-free low-smoke flame-retardant polyolefin sheath material is used. It will not release toxic halogen compounds when burned, and the amount of smoke released during combustion is relatively low, which is beneficial to the safe evacuation and withdrawal of personnel in case of fire, and can also reduce environmental pollution.

[0019] This cable forms a composite fire-resistant structure. Some structures of the composite structure can generate crystal water and carbon dioxide under flame burning or high-temperature conditions, and generate a hard ceramic-like hard shell, which can achieve the effect of layered heat insulation; the composite copper tape shielding layer can not only reduce electromagnetic interference, ensure the stability of the current transmission process, unload short-circuit current and play a grounding protection role, but also form a cavity for containing dry powder, which can improve the heat preservation and heat insulation effect, and the external high temperature can be more effectively isolated here, further improving the fire resistance performance. And this cable does not produce toxic gases during combustion, and the amount of smoke released during combustion is relatively low. It provides sufficient time for personnel evacuation, fire fighting and rescue, and equipment rescue.

[0020] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by those skilled in the art within the scope of the essence of the present invention should also fall within the protection scope of the present invention.

Claims

1. A fire-resistant cable, characterized in that: The invention comprises a plurality of cable cores, wherein the cable core comprises a conductor, a conductor shielding layer is arranged on the outside of the conductor, an insulating layer is arranged on the outside of the conductor shielding layer, an insulating shielding layer is arranged on the outside of the insulating layer, a semi-conductive buffer tape layer is arranged on the outside of the insulating shielding layer, a composite copper tape shielding layer is arranged on the outside of the semi-conductive buffer tape layer, the composite copper tape shielding layer comprises an inner special-shaped copper tape winding layer and an outer flat copper tape covering layer, the special-shaped copper tape winding layer is formed by winding a copper tape with a T-shaped cross-section, adjacent winding turns overlap each other, a cavity is provided between the T-shaped copper tape and the inner semi-conductive buffer tape layer and the outer flat copper tape covering layer, the cavity is filled with dry powder, the outside of the plurality of cable cores is a cable sheath, an insulating filling layer is provided between the cable sheath and the cable core, and the insulating filling layer is filled with extruded ceramic low-smoke halogen-free polyolefin.

2. A fire-resistant cable according to claim 1, characterized in that The cable skin includes from inside to outside the first ceramic silicon fire-resistant mica tape layer, the extruded low-smoke halogen-free polyolefin oxygen barrier layer, the second ceramic silicon fire-resistant mica tape layer, the galvanized steel tape layer, the third ceramic silicon fire-resistant mica tape layer, and the outer sheath.

3. A fire-resistant cable according to claim 1, characterized in that :The conductor shielding layer is extruded from a semi-conductive inner shielding material.

4. A fire-resistant cable according to claim 1, characterized in that :The insulation layer is made of cross-linked polyethylene material.

5. A fire-resistant cable according to claim 1, characterized in that :The insulating shielding layer is extruded from a semi-conductive outer shielding material.

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