Aluminum sheath flexible mineral fireproof cable and preparation method thereof

Abstract

The invention discloses an aluminum sheath flexible mineral fireproof cable and a preparation method thereof. According to the cable, a rib supporting framework with outer surface grids is formed on the outer side of an embossed aluminum sheath, the grids of the rib supporting framework are filled with an inorganic mineral powder mud layer, and an embossed aluminum-framework-inorganic mineral powder mud composite sheath is formed due to fixation of ribs and dents. And the inorganic mineral powder mud is not easy to displace on the outer surface of the rib supporting framework under the wrapping of the outer sheath, so that the impact resistance of the whole cable body is improved, and the integrity of the cable body is particularly kept at high temperature. According to the preparation method of the flexible mineral fireproof cable with the aluminum sheath, provided by the invention, the convex rib supporting framework with the outer surface grids is formed outside the embossed aluminum sheath through constant-speed extrusion, the inorganic mineral powder mud layer is formed through constant-pressure extrusion, and the outer sheath is extruded, so that the inorganic mineral powder mud layer is ensured to be fully filled and fixed in the outer surface grids of the convex rib supporting framework; and inorganic mineral powder mud is not easy to migrate.

Description

Technical Field

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

[0002] Flexible insulated mineral cable is a special cable with excellent fireproof and high temperature resistance. It is suitable for places with extremely high safety requirements, such as high-rise buildings, subways, nuclear power plants, etc. Flexible mineral insulated cable is mainly composed of multi-strand copper strands, mica tape mineral insulation wrapping, alkali-free glass fiber dense filling, copper tape longitudinally wrapped and welded copper tube sheath, mineral flame retardant powder mud and 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 powered on for a certain period of time, opening a green channel for firefighters and giving them enough time for rescue.

[0003] Among them, the copper tube sheath structure is crucial to ensure that the cable is powered on and running in the event of a fire. The challenges faced by cables in the event of a fire are not only the requirements for high temperature resistance and flame retardancy, but also the mechanical impact 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 a strong impact on the cables laid in the building, damaging the cables and causing leakage, which is dangerous. The copper tube sheath provides good resistance to mechanical impact and protects the fire-resistant cable from normal operation in the event of a fire, but the copper tube sheath is expensive and has poor bending performance.

[0004] Chinese patent document CN217386744U provides an isolated flexible insulated fireproof cable, which uses corrugated aluminum sheath instead of copper tube sheath to effectively reduce the cost. However, the mechanical impact resistance is correspondingly weakened. Summary of the invention

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

[0006] To achieve the above object, according to one aspect of the present invention, there is provided an aluminum sheathed flexible mineral fireproof cable, comprising a cable core composed of a conductor and a mineral insulation filling layer, the outer side of which is sequentially coated with: a corrugated aluminum sheath, a convex ridge support skeleton, an inorganic mineral powder mud layer, and an outer sheath;

[0007] The corrugated aluminum sheath has circumferential corrugations;

[0008] 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;

[0009] 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;

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

[0011] Preferably, in the aluminum sheathed flexible mineral fireproof cable, the inorganic mineral powder mud is a fireproof material, which is a muddy mixture formed by adding water to ceramic reaction powder raw materials.

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

[0013] Preferably, in the aluminum sheathed flexible mineral fire-resistant cable, the non-ceramic reaction powder raw material is a mixture of sodium silicate and magnesium hydroxide in a molar ratio of 1:1.

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

[0015] Preferably, in the aluminum sheathed flexible mineral fire-proof cable, on the cable cross section, the ratio of the minimum distance to the maximum distance between the outer sheath and the ridge support skeleton is between 1 / 5 and 2 / 3; the ridge support skeleton is made of a polymer thermoplastic material, preferably high-density polyethylene, and the distance between adjacent ridges 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 to 10 mm, and it is a flame-retardant polymer thermoplastic material, preferably a low-smoke halogen-free sheath.

[0016] Preferably, in the aluminum sheathed flexible mineral fire resistant cable, the ridges of the ridge support skeleton are straight or spiral, and are vertically staggered with the corrugations of the corrugated aluminum sheath.

[0017] Preferably, the corrugated aluminum sheath of the aluminum sheathed flexible mineral fire resistant cable has a corrugation depth of 1 to 3 mm, and is spiral corrugation or annular corrugation.

[0018] Preferably, in the aluminum sheathed flexible mineral fire-resistant cable, 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; the mineral insulation filling layer is alkali-free glass fiber filling; preferably, the cable core is wrapped with an insulating tape.

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

[0020] (1) longitudinally wrapping the cable core with an aluminum strip, drawing and forming the cable core, and corrugating the cable core with an aluminum strip by a corrugating machine to form a corrugated aluminum sheath on the outer side of the cable core;

[0021] (2) passing the cable core with the 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 the corrugated aluminum sheath, and obtaining a cable core with a ridge support skeleton;

[0022] (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;

[0023] (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.

[0024] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0025] The aluminum sheathed flexible mineral fireproof cable provided by the present invention has a ridge support skeleton with an outer surface grid formed on the outside of the corrugated aluminum sheath, and an inorganic mineral powder mud layer is filled in the grid of the ridge support skeleton. Due to the fixation of the ridges and indentations, a corrugated aluminum-skeleton-inorganic mineral powder mud composite sheath is formed. The inorganic mineral powder mud is not easy to displace on the outer surface of the ridge support skeleton under the wrapping of the outer sheath, thereby improving the overall impact resistance of the cable body, especially maintaining the integrity of the cable body at high temperatures.

[0026] The preferred embodiment of the present invention adopts ceramic reaction split raw materials as the fireproof material of the inorganic mineral sludge layer. The inorganic mineral sludge undergoes a ceramic reaction at high temperature, which greatly improves the hardness of the cable body. The outer surface grid of the ridge support skeleton avoids the stress accumulation caused by the ceramic reaction and high temperature, thereby effectively reducing the risk of metal fatigue fracture of the aluminum sheath due to local stress accumulation in the cable body at high temperature, and improving the impact resistance and seismic resistance at high temperature.

[0027] The preparation method of the aluminum sheathed flexible mineral fireproof cable provided by the present invention comprises the following steps: extruding at a constant speed outside the corrugated aluminum sheath to form a convex rib support skeleton with an outer surface grid, extruding at a constant pressure to form an inorganic mineral powder mud layer, and extruding an outer sheath to ensure that the inorganic mineral powder mud layer is fully filled and fixed in the outer surface grid of the convex rib support skeleton, and the inorganic mineral powder mud is not easily migrated. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0030] In all the drawings, the same reference numerals are used to represent the same elements or structures, wherein: 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 ridge support skeleton, 6 is an inorganic mineral powder mud layer, 7 is an outer sheath, and 8 is an insulating tape. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended 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 fireproof cable provided by the present invention comprises a cable core, the outer side of which is sequentially covered with a corrugated aluminum sheath, a convex ridge support frame, an inorganic mineral powder mud layer, and an outer sheath;

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

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

[0035] 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;

[0036] 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;

[0037] The strength of aluminum sheath is generally lower than that of copper sheath, and it is weaker than copper sheath in terms of impact resistance. In addition, in the event of a fire, repeated vibrations can cause metal fatigue and breakage at the corrugation of the corrugated aluminum sheath. In order to improve the impact resistance of the aluminum sheath, we tried to make up 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 is increased, due to the fluidity of the inorganic mineral powder mud, the inorganic mineral powder layer is locally deformed, and the inorganic mineral powder layer accumulates stress under high-temperature sintering tests. The mechanical strength of the inorganic mineral powder layer is reduced, which is not helpful for improving the overall impact resistance of the cable at high temperatures. In order to solve the problem of the fluidity of the inorganic mineral powder mud, we add a convex rib support frame between the inorganic mineral powder mud layer and the corrugated aluminum sheath. Through the interlacing of the axial ribs and the circumferential indentations, a grid is formed, so that the inorganic mineral powder mud layer is 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-convex rib support skeleton-inorganic mineral powder mud layer effectively improves the overall impact resistance of the cable at high temperatures. At the same time, the inorganic mineral powder mud layer is filled under the corrugation of the corrugated aluminum sheath through the convex rib support skeleton. At high temperatures, the inorganic mineral powder mud layer undergoes a ceramic reaction, supporting the corrugation 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 convex rib support skeleton of the polymer organic material also has a certain role in absorbing stress, helping to reduce the probability of cable fracture. The grid on the outer surface of the convex rib support skeleton can also fix more inorganic mineral powder mud to form 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 inorganic mineral powder mud during high-temperature sintering affect the preparation process of the cable, the thickness of the inorganic mineral powder mud layer, and the impact resistance and seismic resistance of the cable. The inorganic mineral powder mud of the present invention is a fireproof material, preferably a muddy mixture of ceramic reaction powder raw materials and water. Under normal circumstances, the ceramic reaction powder raw materials do not affect the bending of the cable, which is convenient for winding and transportation. In high-temperature conditions such as fire, the powder raw materials undergo a ceramic reaction, and the hardness is greatly improved to protect the cable. The mass ratio of the non-ceramic reaction powder raw material to water is 0.5 to 2: 1, so as to provide good fluidity and facilitate extrusion to prepare the inorganic mineral powder mud layer. The present invention preferably uses a mixture of sodium silicate and magnesium hydroxide in a molar ratio of 1: 1. When the mass ratio of the non-ceramic reaction powder raw material to water is 0.66 to 1.4: 1, it has good fluidity, and the powder mud finally forms hydrated sodium silicate and hydrated magnesium hydroxide, and there is no free water to ensure electrical performance while maintaining volume stability during high-temperature sintering.

[0039] In order to fix the inorganic mineral powder mud layer well, the distance between adjacent ridges of the ridge support skeleton is between 3 and 18 mm, and the distance between adjacent indentations is between 3 mm and 18 mm; on the cable cross section, the ratio of the minimum distance to the maximum distance between the outer sheath and the ridge support skeleton is between 1 / 5 and 2 / 3. Even if the inorganic mineral powder mud layer filled in the grid generates tensile stress or compressive stress during the high-temperature ceramic reaction, the stress cannot be concentrated on a certain embossing in the length direction of the cable body due to the dispersion of the ridge support skeleton, and the risk of aluminum sheath breakage is reduced by stress dispersion.

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

[0041] The outer sheath covers and fixes the inorganic mineral powder mud layer, 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 polymer thermoplastic material, preferably a low-smoke halogen-free sheath.

[0042] The preparation method of the aluminum sheathed flexible mineral fireproof cable provided by the present invention comprises the following steps:

[0043] (1) longitudinally wrapping the cable core with an aluminum strip, drawing and forming the cable core, and corrugating the cable core with an aluminum strip by a corrugating machine to form a corrugated aluminum sheath on the outer side of the cable core;

[0044] (2) The cable core with the corrugated aluminum sheath obtained in step (1) is passed through the die head of the first extruder, and a polymer thermoplastic material with a convex rib support skeleton is extruded at a constant speed, and a base layer and outer ribs of the convex rib support skeleton are formed through an extruder die cover, and a convex rib support skeleton is formed on the outer side of the cable core with the corrugated aluminum sheath to obtain a cable core with a convex rib support skeleton; the first extruder head extrude 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 extruder 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 in the axial direction, and naturally forms a concave groove matching the corrugation of the corrugated aluminum sheath.

[0045] (3) The cable core with the convex ridge support skeleton obtained in step (2) is passed through the second extruder head, and an inorganic mineral powder mud slurry is extruded at a constant pressure. The inorganic mineral powder mud slurry is a muddy mixture of ceramic reaction powder raw materials and water freshly blended in a preset ratio to form an inorganic mineral powder mud layer, and a cable core with an inorganic mineral powder mud layer is obtained; the inorganic mineral powder mud slurry is filled into the outer surface grid of the support skeleton under the pressure applied by the second extruder head and fixed, and the inorganic mineral powder mud separates the thermoplastic convex ridge support skeleton and the outer sheath, so there is no need to cool between the three extrusion processes, and the production efficiency is high. After the inorganic mineral powder mud slurry is extruded, the added water is gradually absorbed as crystal water during the preparation, winding, and transportation process, which does not affect the electrical performance. Under normal circumstances, the inorganic mineral powder mud does not affect the bending performance of the cable, and in high temperature conditions such as fire, the inorganic mineral powder mud is ceramicized and the hardness is greatly improved.

[0046] (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 fireproof cable. After the outer sheath is extruded, it is water-cooled and shaped.

[0047] The following are examples:

[0048] Example 1

[0049] The aluminum sheathed flexible mineral fireproof cable provided in this embodiment has an end face as shown in FIG. Figure 1 As shown, it comprises a cable core, the outer side of which is sequentially covered with a corrugated aluminum sheath, a convex ridge support skeleton, an inorganic mineral powder mud layer, and an outer sheath;

[0050] The cable core comprises 5 strands of copper wires, which are provided with a mica tape insulation layer. The cable core is filled with alkali-free glass fiber, and the cable core has a diameter of 31.87 mm.

[0051] The corrugated aluminum sheath has an outer diameter of 38.67 mm and a corrugation depth of 1.4 mm, and is annular corrugation.

[0052] The rib support skeleton has a base layer and outer ribs, which are high-density polyethylene; the base layer is 1.0 mm thick, the distance d between adjacent ribs is 4.8 mm, and has indentations that match the embossing of the aluminum sheath, and the distance between adjacent indentations is 4.8 mm; the outer ribs extend axially and are interlaced with the indentations of the base layer to form a grid on the outer surface of the rib support skeleton; the ribs are placed vertically and are interlaced with the annular embossing at right angles.

[0053] 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 non-ceramic reaction powder raw material is a mixture of sodium silicate and magnesium hydroxide in a molar ratio of 1:1, and the mass ratio of the non-ceramic reaction powder raw material to water is 0.66-1.4:1.

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

[0055] The outer sheath is a low-smoke 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 comprises the following steps:

[0057] (1) longitudinally wrapping the cable core with an aluminum strip, drawing and forming the cable core, and corrugating the cable core with an aluminum strip by a corrugating machine to form a corrugated aluminum sheath on the outer side of the cable core;

[0058] The cable core is made of 5 strands of copper conductors with mica tape insulation and alkali-free glass fibers.

[0059] (2) passing the cable core with corrugated aluminum sheath obtained in step (1) through the die head of a first extruder, extruding molten high-density polyethylene at a constant speed, and forming the base layer and outer convex ribs of the convex rib support skeleton through an extruder die cover, forming a convex rib support skeleton on the outer side of the cable core with corrugated aluminum sheath, and obtaining a cable core with a convex rib support skeleton;

[0060] (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 prepared by mixing a mixture of sodium silicate and magnesium hydroxide in a molar ratio of 1:1 with water to form a mud-like state, thereby forming an inorganic mineral powder mud layer, and obtaining a cable core with an inorganic mineral powder mud layer;

[0061] (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 fireproof cable. After the outer sheath is extruded, it is water-cooled and shaped.

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

[0063] It can withstand knocking and vibration for 15 minutes under 950℃ flame without breakdown (Z impact test), and the test result shows no breakdown.

[0064] Example 2

[0065] The aluminum sheathed flexible mineral fireproof cable provided in this embodiment has an end face as shown in FIG. Figure 2 As shown, it comprises a cable core, the outer side of which is sequentially covered with a corrugated aluminum sheath, a convex ridge support skeleton, an inorganic mineral powder mud layer, and an outer sheath;

[0066] The cable core comprises 5 strands of copper strands with a mica tape insulation layer. The cable core is filled with alkali-free glass fiber and is wrapped with an insulation tape on the outside. The cable core has a diameter of 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 annular corrugation.

[0068] The rib support skeleton has a base layer and outer ribs, which are high-density polyethylene; the base layer is 1.0 mm thick, the distance between adjacent ribs is 4.5 mm, and has indentations that match the embossing of the aluminum sheath, and the distance between adjacent indentations is 4.5 mm; the outer ribs extend axially and are interlaced with the indentations of the base layer to form a grid on the outer surface of the rib support skeleton; the ribs are placed vertically and are interlaced with the annular embossing at right angles.

[0069] 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 non-ceramic reaction powder raw material is a mixture of sodium silicate and magnesium hydroxide in a molar ratio of 1:1, and the mass ratio of the non-ceramic reaction powder raw material to water is 0.66-1.4:1.

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

[0071] The outer sheath is a low-smoke 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 comprises the following steps:

[0073] (1) longitudinally wrapping the cable core with an aluminum strip, drawing and forming the cable core, and corrugating the cable core with an aluminum strip by a corrugating machine to form a corrugated aluminum sheath on the outer side of the cable core;

[0074] The cable core is made of 5 strands of copper wire with mica tape insulation and alkali-free glass fiber twisted together and wrapped with insulating tape.

[0075] (2) passing the cable core with corrugated aluminum sheath obtained in step (1) through the die head of a first extruder, extruding molten high-density polyethylene at a constant speed, and forming the base layer and outer convex ribs of the convex rib support skeleton through an extruder die cover, forming a convex rib support skeleton on the outer side of the cable core with corrugated aluminum sheath, and obtaining a cable core with a convex rib support skeleton;

[0076] (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 prepared by mixing a mixture of sodium silicate and magnesium hydroxide in a molar ratio of 1:1 with water to form a mud-like state, thereby forming an inorganic mineral powder mud layer, and obtaining a cable core with an inorganic mineral powder mud layer;

[0077] (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 fireproof cable. After the outer sheath is extruded, it is water-cooled and shaped.

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

[0079] It can withstand knocking and vibration for 15 minutes under 950℃ flame without breakdown (Z impact test), and the test result shows no breakdown.

[0080] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in 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 to 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 cable cross section, 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; the ridge support frame is made of a polymer thermoplastic material, preferably high-density polyethylene, and the distance between adjacent ridges 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 to 10 mm, and it is a flame-retardant polymer thermoplastic material, preferably a low-smoke halogen-free sheath.

7. 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.

8. 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 to 3 mm, and the corrugation is spiral corrugation or annular corrugation.

9. 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; the mineral insulation filling layer is filled with alkali-free glass fiber; in a preferred embodiment, the cable core is wrapped with an insulation tape.

10. The method for preparing the aluminum sheathed flexible mineral fire resistant cable according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) longitudinally wrapping the cable core with an aluminum strip, drawing and forming the cable core, and corrugating the cable core with an aluminum strip by a corrugating machine to form a corrugated aluminum sheath on the outer side of the cable core; (2) passing the cable core with the 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 the 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.

Images