A flexible mineral fire-proof cable with an aluminum sheath and its preparation method

Abstract

The present invention discloses a flexible mineral fire-proof cable with an aluminum sheath and a preparation method thereof. A convex rib support skeleton with an outer surface grid is formed outside the corrugated aluminum sheath of the cable, and an inorganic mineral powder mud layer is filled in the grid of the convex rib support skeleton. Due to the fixation of the convex ribs and the indentations, a corrugated aluminum-skeleton-inorganic mineral powder mud composite sheath is formed. The inorganic mineral powder mud is not easily displaced on the outer surface of the convex rib support skeleton under the wrapping of the outer sheath, improving the overall impact resistance of the cable body, especially maintaining the integrity of the cable body at high temperatures. The preparation method of the flexible mineral fire-proof cable with an aluminum sheath provided by the present invention extrudes at a constant speed outside the corrugated aluminum sheath to form a convex rib support skeleton with an outer surface grid, extrudes at a constant pressure to form an inorganic mineral powder mud layer, and extrudes and wraps an outer sheath, ensuring that the inorganic mineral powder mud layer is fully filled and fixed in the outer surface grid of the convex rib support skeleton and is not easily displaced.

Description

Technical Field

[0001] The present invention belongs to the technical field of cables, and more specifically, relates to an aluminum-sheathed flexible mineral fire-resistant cable and a preparation method thereof. Background Art

[0002] A flexible insulated mineral cable is a special cable that has excellent fireproof and high-temperature resistance properties and is suitable for places with extremely high safety requirements, such as high-rise buildings, subways, nuclear power plants, etc. The flexible mineral insulated cable mainly consists of a multi-strand copper stranded wire, mica tape mineral insulation wrapping, non-alkali glass fiber dense filling, a copper tube sheath formed by longitudinally wrapping and welding copper tapes, mineral flame-retardant powder mud, and an outer sheath. This structure makes the cable flexible, easy to install and lay, and has good fire resistance. When a fire occurs, the cable product can continue to be energized and operate for a certain period of time, opening a green channel for firefighters and giving them enough time for rescue.

[0003] Among them, the structure of the copper tube sheath is crucial for ensuring the power supply operation of the cable during a fire. When a fire occurs, the challenges faced by the cable not only include the requirements of high-temperature resistance and flame retardancy, but also include mechanical impacts on the cable body. When a building catches fire, various facilities in it may fall, and the building itself may collapse. These situations may cause strong impacts on the cables laid in the building, damaging the cables and leading to leakage and danger. The copper tube sheath provides good anti-mechanical impact performance, protecting the fire-resistant cable to operate normally during a fire, but the copper tube sheath has a high cost and poor bending performance.

[0004] Chinese Patent Document CN217386744U provides a separated flexible insulated fire-resistant cable, which uses a corrugated aluminum sheath instead of a copper tube sheath, effectively reducing the cost. However, the anti-mechanical impact performance is correspondingly weakened. Summary of the Invention

[0005] In view of the above defects or improvement requirements of the prior art, the present invention provides an aluminum-sheathed flexible mineral fire-resistant cable and a preparation method thereof. The purpose is to fix more inorganic mineral powder mud on the outside of the corrugated aluminum sheath by adding a convex rib support framework with an outer surface grid between the corrugated aluminum sheath and the inorganic mineral powder mud layer, enhancing the anti-impact performance of the cable body, thereby solving the technical problem of the weak anti-impact performance of the existing aluminum-sheathed flexible mineral fire-resistant cable.

[0006] To achieve the above object, according to one aspect of the present invention, an aluminum-sheathed flexible mineral fire-resistant cable is provided, which includes a cable core composed of a conductor and a mineral insulation filling layer, and is sequentially coated on the outside thereof with: a corrugated aluminum sheath, a convex rib support framework, an inorganic mineral powder mud layer, and an outer sheath;

[0007] The corrugated aluminum sheath has circumferential corrugations;

[0008] The convex rib support framework has a base layer and outer convex ribs; the base layer has a uniform thickness and has indentations matching the corrugations of the aluminum sheath; the outer convex ribs extend axially and intersect with the indentations of the base layer to form a grid on the outer surface of the convex rib support framework;

[0009] Inorganic mineral powder mud is filled in the grid on the outer surface of the convex rib support framework to form an inorganic mineral powder mud layer;

[0010] The outer sheath covers and fixes the inorganic mineral powder mud layer.

[0011] Preferably, in the aluminum-sheathed flexible mineral fireproof cable, the inorganic mineral powder mud is a fireproof material, which is a mud-like mixture prepared by adding water to a ceramicized reaction powder raw material.

[0012] Preferably, in the aluminum-sheathed flexible mineral fireproof cable, the mass ratio of the ceramicized reaction powder raw material to water is 0.5 - 2:1.

[0013] Preferably, in the aluminum-sheathed flexible mineral fireproof cable, the ceramicized reaction powder raw material is a mixture with a molar ratio of sodium silicate to magnesium hydroxide of 1:1.

[0014] Preferably, in the aluminum-sheathed flexible mineral fireproof cable, the mass ratio of the ceramicized reaction powder raw material to water is 0.66 - 1.4:1.

[0015] Preferably, in the aluminum-sheathed flexible mineral fireproof cable, on the cross-section of the cable, the ratio of the minimum distance to the maximum distance between the outer sheath and the convex rib support framework is between 1 / 5 and 2 / 3; the convex rib support framework is made of a high molecular thermoplastic material, preferably high-density polyethylene, and the distance between adjacent convex ribs is between 3 and 18 mm, and the distance between adjacent indentations is between 3 and 18 mm; the distance between the inner wall of the outer sheath and the corrugated aluminum sheath is 5 - 10 mm, and it is a flame-retardant high molecular thermoplastic material, preferably a low-smoke and halogen-free sheath.

[0016] Preferably, in the aluminum-sheathed flexible mineral fireproof cable, the convex ribs of the convex rib support framework are straight or spiral and are perpendicularly staggered with the corrugations of the corrugated aluminum sheath.

[0017] Preferably, in the aluminum-sheathed flexible mineral fireproof cable, the corrugation depth of the corrugated aluminum sheath is 1 - 3 mm, and it is a spiral corrugation or a circular corrugation.

[0018] Preferably, in the aluminum-sheathed flexible mineral fireproof cable, the conductor of the cable core is a copper conductor, and a mica tape insulation layer is wrapped outside it; multiple strands of conductors are stranded; the mineral insulation filling layer is filled with non-alkali glass fiber; in a preferred scheme, the cable core has an insulating tape wrapped around it.

[0019] According to another aspect of the present invention, there is provided a method for preparing the aluminum-sheathed flexible mineral fire-proof cable, comprising the following steps:

[0020] (1) Longitudinally wrap the cable core with aluminum tape, and after drawing and forming, corrugate it through a corrugating machine to form a corrugated aluminum sheath on the outer side of the cable core, and prepare a cable core with a corrugated aluminum sheath;

[0021] (2) Pass the cable core with the corrugated aluminum sheath obtained in step (1) through the head of the first extruder, and extrude at a constant speed to form a polymer thermoplastic material for the convex rib support skeleton, and form the base layer and the outer convex ribs of the convex rib support skeleton through the die cover of the extruder, and form a convex rib support skeleton on the outer side of the cable core with the corrugated aluminum sheath to obtain a cable core with a convex rib support skeleton;

[0022] (3) Pass the cable core with the convex rib support skeleton obtained in step (2) through the second extrusion head, and extrude the inorganic mineral powder slurry at a constant pressure. The inorganic mineral powder slurry is a mud-like mixture of a ceramization reaction powder raw material and water freshly mixed in a preset ratio to form an inorganic mineral powder mud layer, and obtain a cable core with an inorganic mineral powder mud layer;

[0023] (4) Pass the inorganic mineral powder mud layer obtained in step (3) through the third extrusion head, and extrude the sheath material to form an outer sheath, and prepare the aluminum-sheathed flexible mineral fire-proof cable.

[0024] Generally speaking, compared with the prior art by the above technical solution conceived by the present invention, the following beneficial effects can be achieved:

[0025] For the aluminum-sheathed flexible mineral fire-proof cable provided by the present invention, a convex rib support skeleton with an outer surface grid is formed on the outer side of the corrugated aluminum sheath, and the inorganic mineral powder mud layer is filled in the grid of the convex rib support skeleton. Due to the fixation of the convex ribs and the concave marks, a corrugated aluminum-skeleton-inorganic mineral powder mud composite sheath is formed. The inorganic mineral powder mud is not easily displaced on the outer surface of the convex rib support skeleton under the wrapping of the outer sheath, improving the overall impact resistance of the cable body, especially maintaining the integrity of the cable body at high temperatures.

[0026] In a preferred solution, the present invention uses a ceramization reaction powder raw material as the fire-proof material for the inorganic mineral powder mud layer. At high temperatures, the inorganic mineral powder mud undergoes a ceramization reaction, greatly improving the hardness of the cable body. The outer surface grid of the convex rib support skeleton avoids stress accumulation caused by the ceramization reaction and high temperatures together, thereby effectively reducing the risk of metal fatigue fracture of the aluminum sheath caused by local stress accumulation in the cable body at high temperatures, and improving the impact resistance and seismic resistance at high temperatures.

[0027] The preparation method of the aluminum-sheathed flexible mineral fire-resistant cable provided by the present invention is to extrude at a constant speed outside the corrugated aluminum sheath to form a convex rib support skeleton with an outer surface grid, extrude at a constant pressure to form an inorganic mineral mud layer, and extrude and wrap an outer sheath, ensuring that the inorganic mineral mud layer is fully filled and fixed in the outer surface grid of the convex rib support skeleton, and it is not easy for the inorganic mineral mud to migrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic diagram of the end face structure of the aluminum-sheathed flexible mineral fire-resistant cable provided in Embodiment 1 of the present invention;

[0029] Figure 2 is a photograph of the end face of the aluminum-sheathed flexible mineral fire-resistant cable provided in Embodiment 2 of the present invention.

[0030] In all the drawings, the same reference numerals are used to represent the same elements or structures, where: 1 is a copper conductor, 2 is a mica tape insulation layer, 3 is an alkali-free glass fiber, 4 is a corrugated aluminum sheath, 5 is a convex rib support skeleton, 6 is an inorganic mineral mud layer, 7 is an outer sheath, and 8 is an insulating tape. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0032] The aluminum-sheathed flexible mineral fire-resistant cable provided by the present invention includes a cable core, and the outside of the cable core is sequentially coated with a corrugated aluminum sheath, a convex rib support skeleton, an inorganic mineral mud layer, and an outer sheath;

[0033] The cable core includes a conductor and a mineral insulation filling layer; the conductor generally adopts a stranded copper conductor, which is stranded by multiple copper conductors, and the outside of the copper conductor is wrapped with a mica tape insulation layer; the mineral insulation filling layer of the cable core generally adopts alkali-free glass fiber filling, and in order to better form a cable and improve the insulation performance, an insulating tape can be wound to form a cable core.

[0034] The outer diameter of the corrugated aluminum sheath is 11-50 mm, and the corrugation depth is 1-3 mm, which is a spiral corrugation or a circular corrugation.

[0035] The convex rib support skeleton has a base layer and outer convex ribs; the thickness of the base layer is uniform and has indentations matching the corrugations of the aluminum sheath; the outer convex ribs extend axially and intersect with the indentations of the base layer to form a grid on the outer surface of the convex rib support skeleton;

[0036] The inorganic mineral powder mud is filled in the outer surface grid of the ribbed support framework to form an inorganic mineral powder mud layer;

[0037] Generally, the strength of the aluminum sheath is lower than that of the copper sheath, and its impact resistance is weaker than that of the copper sheath. In addition, in the event of a fire, repeated vibrations can cause metal fatigue and fracture at the corrugated areas of the corrugated aluminum sheath. To improve the impact resistance of the aluminum sheath, we tried to compensate for the decrease in impact strength caused by the corrugated aluminum sheath by thickening the inorganic mineral powder layer. However, after the inorganic mineral powder layer was increased, due to the fluidity of the inorganic mineral powder mud, local deformation of the inorganic mineral powder layer occurred. Stress accumulated at the sintering test of the accumulated area of the inorganic mineral powder layer, and the mechanical strength decreased at the area where the inorganic mineral powder layer was lost, which was not helpful for improving the overall impact resistance of the cable at high temperatures. To solve the fluidity problem of this inorganic mineral powder mud, we added a ribbed support framework between the inorganic mineral powder mud layer and the corrugated aluminum sheath. By staggering the axial ribs and circumferential indentations, a grid was formed, allowing the inorganic mineral powder mud layer to be filled in the grid, thereby fixing the inorganic mineral powder mud layer and reducing its flow. The composite structure formed by the corrugated aluminum sheath - ribbed support framework - inorganic mineral powder mud layer effectively improved the overall impact resistance of the cable at high temperatures. At the same time, the inorganic mineral powder mud layer was filled under the corrugations of the corrugated aluminum sheath through the ribbed support framework. At high temperatures, the inorganic mineral powder mud layer undergoes a ceramization reaction, supporting the corrugated areas of the corrugated aluminum sheath, reducing the degree of metal fatigue of the corrugated aluminum sheath during vibration, and reducing the probability of fracture. At the same time, the ribbed support framework made of polymer organic materials also has a certain stress absorption effect, helping to reduce the probability of cable fracture. The outer surface grid of the ribbed support framework can also fix more inorganic mineral powder mud, forming a thicker inorganic mineral powder mud layer, thereby further improving the overall strength of the cable.

[0038] As mentioned above, the fluidity, volume stability and strength of the inorganic mineral powder mud during high-temperature sintering affect the cable manufacturing process, the thickness of the inorganic mineral powder mud layer, as well as the impact resistance and seismic resistance of the cable. The inorganic mineral powder mud of the present invention is a fireproof material, preferably a mud-like mixture prepared by adding water to a ceramization reaction powder raw material. Under normal circumstances, the ceramization reaction powder raw material does not affect the bending of the cable, facilitating winding and transportation. In the event of high temperatures such as a fire, the powder raw material undergoes a ceramization reaction, and the hardness is greatly improved to protect the cable. The mass ratio of the ceramization reaction powder raw material to water is 0.5 - 2:1 to provide good fluidity for facilitating the extrusion to prepare the inorganic mineral powder mud layer. The present invention preferably uses a mixture of sodium silicate and magnesium hydroxide with a molar ratio of 1:1 as the ceramization reaction powder raw material. When the mass ratio of the ceramization reaction powder raw material to water is 0.66 - 1.4:1, it has good fluidity. The powder mud finally forms hydrated sodium silicate and hydrated magnesium hydroxide, without free water, ensuring electrical performance and maintaining volume stability during the high-temperature sintering process.

[0039] To ensure good fixation of the inorganic mineral powder layer, for the ribbed support framework, the distance between adjacent ribs is between 3 and 18 mm, and the distance between adjacent indentations is between 3 mm and 18 mm; in the cross-section of the cable, the ratio of the minimum distance to the maximum distance between the outer sheath and the ribbed support framework is between 1 / 5 and 2 / 3. For the inorganic mineral powder layer filled in the grid, even if tensile stress or compressive stress is generated during the high-temperature ceramization reaction, due to the dispersion of the ribbed support framework, the stress cannot concentrate on a certain corrugation in the cable body length direction, and the risk of the aluminum sheath breaking is reduced through stress dispersion.

[0040] The ribbed support framework is made of a polymer thermoplastic material, preferably high-density polyethylene (HDPE).

[0041] The outer sheath wraps and fixes the inorganic mineral powder layer. The distance between the inner wall of the outer sheath and the corrugated aluminum sheath is 5 - 10 mm. It is a flame-retardant polymer thermoplastic material, preferably a low-smoke and halogen-free sheath.

[0042] The preparation method of the aluminum-sheathed flexible mineral fire-resistant cable provided by the present invention includes the following steps:

[0043] (1) Longitudinally wrap the cable core with aluminum tape, and after drawing and forming, corrugate it through a corrugating machine to form a corrugated aluminum sheath on the outside of the cable core, and prepare a cable core with a corrugated aluminum sheath.

[0044] (2) Pass the cable core with a corrugated aluminum sheath obtained in step (1) through the head of the first extruder, and extrude at a constant speed to form a polymer thermoplastic material for the ribbed support framework, and form the base layer and outer ribs of the ribbed support framework through the extrusion die cover of the extruder, and form a ribbed support framework on the outside of the cable core with a corrugated aluminum sheath to obtain a cable core with a ribbed support framework; the first extrusion head extrudes the polymer thermoplastic material at a constant speed, that is, the volume of the polymer thermoplastic material extruded per unit time is the same. The extrusion die cover determines the cross-sectional shape of the polymer thermoplastic material, and the polymer thermoplastic material forms a base layer with the same thickness axially, and naturally forms indentations matching the corrugations of the corrugated aluminum sheath.

[0045] (3) Pass the cable core with the convex rib support skeleton obtained in step (2) through the second extrusion head, and extrude the inorganic mineral powder slurry at a constant pressure. The inorganic mineral powder slurry is a mud-like mixture of the ceramization reaction powder raw material and water freshly blended according to a preset ratio, forming an inorganic mineral powder mud layer, and obtaining a cable core with an inorganic mineral powder mud layer; the inorganic mineral powder slurry is filled into the outer surface grid of the support skeleton under the pressure applied by the second extrusion head and fixed. The inorganic mineral powder mud separates the thermoplastic formed convex rib support skeleton and the outer sheath. Therefore, there is no need for cooling between the three extrusion processes, and the production efficiency is relatively high. After the inorganic mineral powder slurry is extruded, the added water is gradually absorbed as crystal water during the processes of preparation, winding, and transportation, which does not affect the electrical performance. Under normal circumstances, the inorganic mineral powder mud does not affect the bending performance of the cable. However, in high-temperature situations such as fires, the inorganic mineral powder mud undergoes ceramization and its hardness increases significantly.

[0046] (4) Pass the cable core with the inorganic mineral powder mud layer obtained in step (3) through the third extrusion head, and extrude the sheath material to form an outer sheath, thus preparing the aluminum sheath flexible mineral fire-resistant cable. After the outer sheath is extruded, it is shaped by water cooling.

[0047] The following are the embodiments:

[0048] Embodiment 1

[0049] The aluminum sheath flexible mineral fire-resistant cable provided in this embodiment has an end face as Figure 1 shown, including a cable core, and an extruded corrugated aluminum sheath, a convex rib support skeleton, an inorganic mineral powder mud layer, and an outer sheath are sequentially coated on the outside of the cable core;

[0050] The cable core includes 5-strand copper stranded wire, which has a mica tape insulation layer. The cable core is filled with alkali-free glass fiber, and the diameter of the cable core is 31.87 mm.

[0051] The outer diameter of the extruded corrugated aluminum sheath is 38.67 mm, and the corrugation depth is 1.4 mm, which is a circular corrugation.

[0052] The convex rib support skeleton has a base layer and outer convex ribs, and is made of high-density polyethylene; the thickness of the base layer is 1.0 mm, the distance d between adjacent convex ribs is 4.8 mm, and it has indentations matching the corrugations of the aluminum sheath, and the distance between adjacent indentations is 4.8 mm; the outer convex ribs extend axially and intersect with the indentations of the base layer to form the outer surface grid of the convex rib support skeleton; the convex ribs are placed vertically and intersect perpendicularly with the circular corrugations.

[0053] The inorganic mineral powder mud is filled in the outer surface grid of the convex rib support skeleton to form an inorganic mineral powder mud layer; the ceramization reaction powder raw material is a mixture of sodium silicate and magnesium hydroxide with a molar ratio of 1:1, and the mass ratio of the ceramization reaction powder raw material to water is 0.66 - 1.4:1.

[0054] On the cross-section of the cable, the ratio of the minimum distance to the maximum distance between the outer sheath and the ribbed support framework is 1 / 3.

[0055] The outer sheath is a low-smoke and halogen-free sheath with an inner diameter of 49.87 mm.

[0056] The preparation method of the aluminum-sheathed flexible mineral fire-resistant cable provided in this embodiment includes the following steps:

[0057] (1) Longitudinally wrap the cable core with aluminum tape, and after drawing and forming, roll it with a grooving machine to form a grooved aluminum sheath on the outside of the cable core, and prepare a cable core with a grooved aluminum sheath;

[0058] The cable core is stranded by 5 copper conductors with mica tape insulation layers and non-alkali glass fibers.

[0059] (2) Pass the cable core with the grooved aluminum sheath obtained in step (1) through the head of the first extruder, and extrude the molten high-density polyethylene at a constant speed, and form the base layer and the outer ribs of the ribbed support framework through the die cover of the extruder, and form a ribbed support framework on the outside of the cable core with the grooved aluminum sheath to obtain a cable core with a ribbed support framework;

[0060] (3) Pass the cable core with the ribbed support framework obtained in step (2) through the second extrusion head, and extrude the inorganic mineral powder slurry at a constant pressure. The inorganic mineral powder slurry is a mixture of sodium silicate and magnesium hydroxide with a molar ratio of 1:1 freshly mixed with water into a mud shape to form an inorganic mineral powder mud layer, and obtain a cable core with an inorganic mineral powder mud layer;

[0061] (4) Pass the inorganic mineral powder mud layer obtained in step (3) through the third extrusion head, and extrude the sheath material to form the outer sheath, and prepare the aluminum-sheathed flexible mineral fire-resistant cable. After the outer sheath is extruded, it is cooled and shaped.

[0062] According to Part (3) Line Integrity of BS6387:2013 British Standard CWZ:

[0063] Withstand the knocking and vibration for 15 minutes under a 950 °C flame without breakdown (Z item impact test), and the test result is no breakdown.

[0064] Example 2

[0065] The end face of the aluminum-sheathed flexible mineral fire-resistant cable provided in this embodiment is as Figure 2 shown, including a cable core, and a grooved aluminum sheath, a ribbed support framework, an inorganic mineral powder mud layer, and an outer sheath are sequentially coated on the outside of the cable core;

[0066] The cable core includes 5 copper stranded wires with mica tape insulation layers, the cable core is filled with non-alkali glass fibers, and an insulating tape is wrapped around the outside, and the diameter of the cable core is 21.75 mm.

[0067] The corrugated aluminum sheath has an outer diameter of 27.55 mm and a corrugation depth of 1.4 mm, and is a circular corrugation.

[0068] The ribbed support skeleton has a base layer and outer ribs, and is made of high-density polyethylene; the thickness of the base layer is 1.0 mm, the distance between adjacent ribs is 4.5 mm, and it has indentations matching the corrugations of the aluminum sheath, and the distance between adjacent indentations is 4.5 mm; the outer ribs extend axially and intersect with the indentations of the base layer to form a grid on the outer surface of the ribbed support skeleton; the ribs are placed vertically and intersect perpendicularly with the circular corrugations.

[0069] Inorganic mineral powder mud is filled in the grid on the outer surface of the ribbed support skeleton to form an inorganic mineral powder mud layer; the raw material of the non-ceramicized reaction powder is a mixture of sodium silicate and magnesium hydroxide with a molar ratio of 1:1, and the mass ratio of the non-ceramicized reaction powder raw material to water is 0.66 - 1.4:1.

[0070] On the cross-section of the cable, the ratio of the minimum distance to the maximum distance between the outer sheath and the ribbed support skeleton is 2 / 3.

[0071] The outer sheath is a low-smoke and halogen-free sheath with an inner diameter of 38.35 mm.

[0072] The preparation method of the aluminum-sheathed flexible mineral fire-resistant cable provided in this embodiment includes the following steps:

[0073] (1) Longitudinally wrap the cable core with aluminum tape, and after drawing and forming, corrugate it through a corrugating machine to form a corrugated aluminum sheath on the outside of the cable core, and prepare a cable core with a corrugated aluminum sheath.

[0074] The cable core is stranded by 5 copper wires with mica tape insulation layers and non-alkali glass fibers, and an insulating tape is wrapped around it.

[0075] (2) Pass the cable core with the corrugated aluminum sheath obtained in step (1) through the head of the first extruder, extrude the molten high-density polyethylene at a constant speed, and form the base layer and outer ribs of the ribbed support skeleton through the die cover of the extruder to form a ribbed support skeleton on the outside of the cable core with the corrugated aluminum sheath, and obtain a cable core with a ribbed support skeleton.

[0076] (3) Pass the cable core with the ribbed support skeleton obtained in step (2) through the second extrusion head, and extrude the inorganic mineral powder mud material at a constant pressure. The inorganic mineral powder mud material is freshly adjusted to a mud shape by mixing a mixture of sodium silicate and magnesium hydroxide with a molar ratio of 1:1 and water to form an inorganic mineral powder mud layer, and obtain a cable core with an inorganic mineral powder mud layer.

[0077] (4) Pass the cable core with the inorganic mineral powder mud layer obtained in step (3) through the third extrusion head, extrude the sheath material to form an outer sheath, and prepare the aluminum-sheathed flexible mineral fire-resistant cable. After the outer sheath is extruded, it is water-cooled and shaped.

[0078] According to Part (3) Line Integrity of the British Standard CWZ of BS6387:2013:

[0079] Withstand percussion vibration for 15 minutes under a 950 °C flame without breakdown (Z item impact test), and the test result is no breakdown.

[0080] It is easy for those skilled in the art to understand that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An aluminum sheathed flexible mineral fire resistant cable, characterized in that: The cable core consists of a conductor and a mineral insulation filling layer, and the outer side is covered in sequence: Corrugated aluminum sheath, ridge support frame, inorganic mineral powder mud layer, and outer sheath; The corrugated aluminum sheath has circumferential corrugations; The ridge support frame comprises a base layer and outer ridges; the base layer has uniform thickness and has indentations matching the corrugation of the aluminum sheath; the outer ridges extend axially and intersect with the indentations of the base layer to form a grid on the outer surface of the ridge support frame; Inorganic mineral powder mud is filled in the outer surface grid of the convex ridge support skeleton to form an inorganic mineral powder mud layer; The outer sheath covers and fixes the inorganic mineral mud layer.

2. The aluminum sheathed flexible mineral fire resistant cable according to claim 1, characterized in that: The inorganic mineral powder mud is a fireproof material, which is a muddy mixture formed by adding water to ceramic reaction powder raw materials.

3. The aluminum sheathed flexible mineral fire resistant cable according to claim 2, characterized in that: The mass ratio of the non-ceramic reaction powder raw material to water is 0.5-2:

1.

4. The aluminum sheathed flexible mineral fire resistant cable according to claim 2, characterized in that: The non-ceramic reaction powder raw material is a mixture of sodium silicate and magnesium hydroxide in a molar ratio of 1:

1.

5. The aluminum sheathed flexible mineral fire resistant cable according to claim 3 or 4, characterized in that: The mass ratio of the non-ceramic reaction powder raw material to water is 0.66-1.4:

1.

6. The aluminum sheathed flexible mineral fire resistant cable according to claim 2, characterized in that: On the cross section of the cable, the ratio of the minimum distance to the maximum distance between the outer sheath and the ridge support frame is between 1 / 5 and 2 / 3.

7. The aluminum sheathed flexible mineral fire resistant cable according to claim 2, characterized in that: The ridge support frame is made of a polymer thermoplastic material, the distance between adjacent ridges is between 3 and 18 mm, and the distance between adjacent indentations is between 3 and 18 mm.

8. The aluminum sheathed flexible mineral fire resistant cable according to claim 2, characterized in that: The distance between the inner wall of the outer sheath and the corrugated aluminum sheath is 5-10 mm, and the outer sheath is made of flame-retardant polymer thermoplastic material.

9. The aluminum sheathed flexible mineral fire resistant cable according to claim 6, characterized in that: The ridges of the ridge support frame are vertical or spiral, and are vertically staggered with the corrugations of the corrugated aluminum sheath.

10. The aluminum sheathed flexible mineral fire resistant cable according to claim 1, characterized in that: The corrugation depth of the corrugated aluminum sheath is 1-3 mm, and the corrugation is spiral corrugation or annular corrugation.

11. The aluminum sheathed flexible mineral fire resistant cable according to claim 1, characterized in that: The conductor of the cable core is a copper conductor, the outer side of which is wrapped with a mica tape insulation layer; multiple strands of conductors are twisted; and the mineral insulation filling layer is filled with alkali-free glass fiber.

12. The aluminum sheathed flexible mineral fire resistant cable according to claim 11, characterized in that: The cable core has an insulating tape wrap.

13. The method for preparing the aluminum sheathed flexible mineral fire resistant cable according to any one of claims 1 to 12, characterized in that: The following steps are involved: (1) The cable core is longitudinally wrapped with an aluminum strip, drawn into shape, and then corrugated by a corrugating machine to form a corrugated aluminum sheath on the outside of the cable core, thereby preparing a cable core with a corrugated aluminum sheath; (2) passing the cable core with corrugated aluminum sheath obtained in step (1) through the die head of a first extruder, extruding a polymer thermoplastic material forming a ridge support skeleton at a constant speed, and forming a base layer and outer ridges of the ridge support skeleton through an extruder die cover, forming a ridge support skeleton on the outer side of the cable core with corrugated aluminum sheath, and obtaining a cable core with a ridge support skeleton; (3) passing the cable core with a ridge support skeleton obtained in step (2) through a second extruder head, and extruding an inorganic mineral powder mud slurry at a constant pressure, wherein the inorganic mineral powder mud slurry is a muddy mixture of a ceramic reaction powder raw material and water freshly blended in a preset ratio, to form an inorganic mineral powder mud layer, thereby obtaining a cable core with an inorganic mineral powder mud layer; (4) The inorganic mineral powder mud layer obtained in step (3) is passed through a third extruder head to extrude the sheath material to form an outer sheath, thereby preparing the aluminum sheathed flexible mineral fire-resistant cable.

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