Medium-voltage fire-resistant cable

Abstract

The utility model relates to the technical field of cables, and discloses a medium-voltage fire-resistant cable, which comprises a cable body, the cable body is provided with a sheath layer, an armor layer, a fire-resistant layer, an oxygen barrier layer, a shielding layer and a conductor from outside to inside, the armor layer is internally provided with a plurality of groups of omega memory alloy frameworks and a plurality of groups of insertion cylinders, the omega memory alloy framework is wound on the outer side of the fireproof layer and located in the armor layer, the insertion cylinder is fixed to an inner ring of the omega memory alloy framework, an annular metal wire penetrates through the insertion cylinder, the bottom end of the insertion cylinder is provided with an arc-shaped block abutting against a conductor, and the insertion cylinder penetrates through the armor layer, the fireproof layer, the oxygen isolation layer and the shielding layer. According to the utility model, the stability of the internal structure is enhanced, the complete power supply time of the cable in flames is prolonged, the power supply reliability in fire disasters is improved, and the continuous operation of key equipment is guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of cables, in particular to a medium-voltage fire-resistant cable. Background Art

[0002] Medium-voltage fire-resistant cables, rated at 3-35kV, are designed to maintain circuit integrity in the event of a fire. They utilize fire-resistant conductors, ensuring continuous power supply during fires. They are primarily used in high-rise building fire protection systems, subway tunnels, petrochemical plants, and other locations with stringent power supply requirements. They ensure the proper operation of emergency equipment such as fire pumps and emergency lighting, minimizing fire damage.

[0003] Although traditional fire-resistant cables use fire-resistant materials to wrap conductors, due to the differences in thermal expansion coefficients of the various layers of materials under high fire temperatures, they are prone to problems such as loose structure and interlayer separation, leading to failure of the fire-resistant layer or displacement of the conductor, affecting circuit integrity. To this end, we propose a medium-voltage fire-resistant cable. Utility Model Content

[0004] The purpose of the present utility model is to provide a medium voltage fire-resistant cable to solve the problems raised in the above background technology.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solutions: a medium-voltage fire-resistant cable, comprising a cable body, wherein the cable body is provided with a sheath layer, an armor layer, a fire-resistant layer, an oxygen-isolating layer, a shielding layer, and a conductor from the outside to the inside, wherein a plurality of groups of Ω memory alloy skeletons and a plurality of groups of inserts are provided in the armor layer, wherein the Ω memory alloy skeleton is wound around the outside of the fire-resistant layer and inside the armor layer, wherein the insert is fixed to the inner ring of the Ω memory alloy skeleton, wherein an annular metal wire is passed through the inside of the insert, and wherein the bottom end of each insert is provided with an arc-shaped block that abuts against the conductor.

[0006] Preferably, the insert is provided with an armor layer, a fire-resistant layer, an oxygen-isolating layer and a shielding layer.

[0007] Preferably, the insert and the arc block are both made of heat-resistant silicone rubber.

[0008] Preferably, a plurality of groups of the annular metal wire arrays are distributed inside the insert.

[0009] Preferably, the sheath layer is made of low-smoke halogen-free polyolefin material, the armor layer is made of steel strip metal material, the fire-resistant layer is a ceramic silicone rubber tape wrapped structure, the oxygen isolation layer is a high oxygen index halogen-free material, and the shielding layer is a composite structure of copper tape wrapped and semi-conductive material.

[0010] Compared with existing technologies, this invention offers the following advantages: the Ω memory alloy skeleton contracts due to temperature rise, radially tightening the internal layers, preventing loosening caused by flame impact and ensuring a tight fit between layers even at high temperatures. Simultaneously, the circular metal wire expands due to heat, stretching the heat-resistant silicone rubber insert. This elastic deformation generates buffering tension, tightening the layers. Furthermore, the skeleton contracts, pressing against the conductors through the curved blocks, reducing conductor displacement at high temperatures, enhancing internal structural stability, and extending the cable's full power supply time in flames. This improves power supply reliability during fires and ensures the continued operation of critical equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a structural diagram of the utility model;

[0012] Figure 2 For the utility model Figure 1 A in the middle is an enlarged structural diagram;

[0013] Figure 3 It is a schematic diagram of the cross-sectional layered planar structure of the present invention.

[0014] In the figure: 101, cable body; 1, sheath layer; 2, armor layer; 21, Ω memory alloy skeleton; 22, insert tube; 23, annular metal wire; 24, arc block; 3, fire-resistant layer; 4, oxygen barrier layer; 5, shielding layer; 6, conductor. DETAILED DESCRIPTION

[0015] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0016] See also Figure 1-3 , the utility model provides the following technical solutions:

[0017] Embodiment 1: A medium-voltage fire-resistant cable comprises a cable body 101. The cable body 101 is provided with a sheath layer 1, an armor layer 2, a fire-resistant layer 3, an oxygen barrier layer 4, a shielding layer 5 and a conductor 6 from the outside to the inside. The sheath layer 1 is made of a low-smoke halogen-free polyolefin material, the armor layer 2 is made of a steel strip metal material, the fire-resistant layer 3 is a ceramic silicone rubber tape wrapped structure, the oxygen barrier layer 4 is a high oxygen index halogen-free material, and the shielding layer 5 is a composite structure of copper tape wrapped and semi-conductive material.

[0018] During use, when operating normally, the low-smoke halogen-free polyolefin material of the sheath layer 1 ensures environmental safety; the steel belt of the armor layer 2 provides mechanical protection to resist external extrusion and impact; the ceramic silicone rubber belt of the fire-resistant layer 3 is flexible at room temperature, and sintered into a ceramic hard shell when encountering fire to block the flame; the oxygen-isolating layer 4 delays oxygen penetration, and cooperates with the copper belt and semi-conductive material of the shielding layer 5 to balance the electric field, ensuring stable power transmission of the conductor 6.

[0019] Embodiment 2: The technical solution of this embodiment is different from that of Embodiment 1 and includes: multiple groups of Ω memory alloy skeletons 21 and multiple groups of inserts 22 are arranged in the armor layer 2, the Ω memory alloy skeleton 21 is wound around the outside of the fire-resistant layer 3 and inside the armor layer 2, the inserts 22 are fixed to the inner ring of the Ω memory alloy skeleton 21, an annular metal wire 23 is passed through the inside of the inserts 22, and an arc block 24 is provided at the bottom end of the inserts 22 to abut against the conductor 6. The inserts 22 pass through the armor layer 2, the fire-resistant layer 3, the oxygen insulation layer 4 and the shielding layer 5. The inserts 22 and the arc block 24 are made of heat-resistant silicone rubber material, and multiple groups of annular metal wires 23 are distributed in an array inside the inserts 22.

[0020] During use, when the cable is exposed to fire, the Ω memory alloy skeleton 21 triggers a shape memory effect due to the rising temperature. Its Ω-shaped structure contracts due to the heat, radially tightening internal layers such as the fire-resistant layer 3 and the oxygen-insulating layer 4 inward, preventing the structure from loosening due to the impact of the flame and ensuring that the layers fit tightly together even at high temperatures. Simultaneously, the annular metal wire 23 expands due to the heat, axially extending the heat-resistant silicone rubber insert 22. The elastic deformation of the silicone rubber generates a buffering tension that tensions each layer. Furthermore, when the Ω memory alloy skeleton 21 contracts inward, it presses against the conductor 6 through the arc block 24, reducing its displacement at high temperatures and strengthening the internal structural stability, thereby extending the cable's full power supply time in flames.

[0021] Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A medium voltage fire-resistant cable, comprising a cable body (101), characterized in that: The cable body (101) is provided with a sheath layer (1), an armor layer (2), a fire-resistant layer (3), an oxygen-isolating layer (4), a shielding layer (5) and a conductor (6) from the outside to the inside, and a plurality of groups of Ω memory alloy skeletons (21) and a plurality of groups of inserts (22) are provided in the armor layer (2). The Ω memory alloy skeleton (21) is wound around the outside of the fire-resistant layer (3) and inside the armor layer (2). The inserts (22) are fixed to the inner ring of the Ω memory alloy skeleton (21). An annular metal wire (23) is passed through the inserts (22). The bottom end of each insert (22) is provided with an arc block (24) that abuts against the conductor (6).

2. A medium voltage fire-resistant cable according to claim 1, characterized in that: The insert (22) is penetrated by an armor layer (2), a fire-resistant layer (3), an oxygen-isolating layer (4), and a shielding layer (5).

3. A medium voltage fire-resistant cable according to claim 1, characterized in that: The insert (22) and the arc-shaped block (24) are both made of heat-resistant silicone rubber.

4. A medium voltage fire-resistant cable according to claim 1, characterized in that: A plurality of groups of annular metal wires (23) are arrayed and distributed inside the insert (22).

5. A medium voltage fire-resistant cable according to claim 1, characterized in that: The sheath layer (1) is made of low-smoke halogen-free polyolefin material, the armor layer (2) is made of steel strip metal material, the fire-resistant layer (3) is a ceramic silicone rubber tape wrapped structure, the oxygen isolation layer (4) is a high oxygen index halogen-free material, and the shielding layer (5) is a composite structure of copper tape wrapped and semi-conductive material.

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