Environment-friendly mineral insulated fire-resistant cable

Abstract

The utility model provides a kind of environment-friendly mineral insulation fire-resistant cable, including conductor core, fire resistance layer, inner sheath and outer sheath, the fire resistance layer includes non-overlapping area and the overlapping area distributed in the two sides of the non-overlapping area along width direction, the thickness of the non-overlapping area is set to twice the thickness of the overlapping area, the overlapping area is mutually laminated when wrapping, make the thickness of the overlapping area and non-overlapping area area outside the conductor core after wrapping, after wrapping forming, ceramified silicon rubber is uniformly distributed in mica layer inside, while ceramified silicon rubber and mica sheet provide stable fire resistance, the entire fire resistance layer has no obvious change on outer diameter, its overlapping area and non-overlapping area smoothly transition, when cable bending, can reduce overlapping closed, and reduce the probability of breakage, powder falling of mica sheet edge area.

Description

Technical Field

[0001] This utility model relates to the field of wire and cable technology, and more specifically to an environmentally friendly mineral-insulated fire-resistant cable. Background Technology

[0002] Environmentally friendly mineral-insulated fire-resistant cables are high-performance cables that use inorganic mineral materials (such as magnesium oxide) as the insulation layer and seamless copper tubes or strips as the sheath, emphasizing environmentally friendly characteristics in both materials and processes. They not only maintain normal operation for extended periods under fire conditions but also possess environmentally friendly and safe characteristics such as halogen-free, low-smoke, low-toxicity, non-flammability, and corrosion resistance. Their environmental friendliness stems from the elimination of traditional halogen-containing polymer materials such as polyvinyl chloride (PVC), thus avoiding the generation of large amounts of dense smoke and corrosive, toxic halogen acid gases during combustion.

[0003] Currently, mineral-insulated cables include rigid mineral cables and flexible mineral cables. Rigid mineral cables use highly compressed mineral powder (such as magnesium oxide powder) as the insulation medium and seamless copper tubes as the sheath layer. They have high hardness and are not convenient for laying. Flexible mineral-insulated cables use continuously wrapped mica tape in combination with longitudinally wrapped copper tape. While maintaining excellent fire resistance, they also make the cable flexible to be close to that of ordinary cables. However, when the mica tape is wrapped, the overlapping seam will cause the edge area of ​​the mica tape to form a protrusion. Since the mica tape is relatively brittle, the edges may be damaged and powder may fall off during the frequent bending and dragging of the cable during installation, which will damage the integrity of the structure. In addition, the overlapping seam can also become a weak point for flames or high-temperature smoke to penetrate, affecting the electrical performance of the cable. Utility Model Content

[0004] In view of the shortcomings of existing mineral-insulated fire-resistant cables, this utility model proposes an environmentally friendly mineral-insulated fire-resistant cable, comprising:

[0005] The conductor core consists of multiple strands of wire twisted together.

[0006] A refractory layer is wrapped around the outside of the conductor core;

[0007] Inner sheath, covering the outside of the refractory layer;

[0008] The outer sheath is extruded onto the outside of the inner sheath;

[0009] The refractory layer along the width direction includes a non-overlapping area and overlapping areas distributed on both sides of the non-overlapping area. The thickness of the non-overlapping area is set to twice the thickness of the overlapping area. During wrapping, the overlapping areas are overlapped to make the thickness of the overlapping and non-overlapping areas on the outside of the conductor core the same after wrapping.

[0010] Preferably, the fire-resistant layer includes two sets of composite mineral insulating tapes, and the two sets of composite mineral insulating tapes are bonded to each other in the overlapping area. In the non-overlapping area, a ceramicized silicone rubber filling structure is provided between the two sets of composite mineral insulating tapes. In the overlapping area, the surfaces of the two sets of composite mineral insulating tapes are provided with overlap filler, and the two sets of overlap filler are centrally symmetrically distributed.

[0011] Preferably, the thickness of the overlap filler is set to 1 / 2 of the thickness of the ceramicized silicone rubber filler structure.

[0012] Preferably, the overlapping filler has a positioning groove on its mating surface.

[0013] Preferably, the overlap filler comprises a ceramicized silicone rubber strip.

[0014] Preferably, the composite mineral insulating tape forms a cavity with a rectangular or parallelogram cross-section in the non-overlapping section, and the ceramicized silicone rubber filling structure fills the cavity.

[0015] Preferably, the bonding area of ​​the composite mineral insulating tape is centrally symmetrically distributed around the central axis of the cavity.

[0016] Preferably, the composite mineral insulating tape includes a mica layer and a substrate layer, wherein the substrate layer is adhered to the inner side of the mica layer, and the substrate layers can be adhered and fixed to each other.

[0017] Preferably, the inner sheath includes a corrugated copper strip, which is longitudinally wrapped around the outside of the refractory layer, and the joints of the corrugated copper strip are welded and sealed.

[0018] Preferably, the outer sheath comprises a halogen-free low-smoke polymer sheath.

[0019] Compared with existing technologies, the advantages of this environmentally friendly mineral-insulated fire-resistant cable are:

[0020] In this environmentally friendly mineral-insulated fire-resistant cable, a ceramicized silicone rubber mica tape with varying thickness in the width direction is used to define the middle area as a non-overlapping area and the two sides as overlapping areas. The overlapping areas are centrally symmetrically distributed. In the non-overlapping area, the ceramicized silicone rubber is located inside the sandwich between two mica layers, and in the overlapping area, it is located outside the single mica layer. However, when the overlapping areas are fully overlapped, the ceramicized silicone rubber is again located inside the two mica layers. While providing stable fire resistance performance, the ceramicized silicone rubber and mica sheets have almost no significant change in the outer diameter of the entire fire-resistant layer. The overlapping area and the non-overlapping area transition smoothly. When the cable is bent, the overlap can be reduced, and the probability of damage and powdering at the edge of the mica sheet can be reduced. Attached Figure Description

[0021] The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component shown in the various figures may be denoted by the same reference numeral. For clarity, not every component is labeled in each figure. Embodiments of various aspects of the present invention will now be described by way of example and with reference to the accompanying drawings.

[0022] Figure 1 This is a schematic diagram of the layered structure of an environmentally friendly mineral-insulated fire-resistant cable according to an embodiment of this utility model.

[0023] Figure 2 This is a schematic diagram of the cross-sectional structure of an environmentally friendly mineral-insulated fire-resistant cable according to an embodiment of this utility model.

[0024] Figure 3 This is a partial structural schematic diagram of the refractory layer shown in an embodiment of the present invention.

[0025] Figure 4 This is a schematic diagram of the overlapping structure of the refractory layer shown in the embodiment of this utility model.

[0026] The attached figures are labeled as follows:

[0027] 10. Conductor core; 11. Wire; 20. Fire-resistant layer; 201. Non-overlapping area; 202. Overlapping area; 21. Composite mineral insulation tape; 211. Mica layer; 212. Substrate layer; 22. Ceramicized silicone rubber filled structure; 23. Overlap filler; 30. Inner sheath; 40. Outer sheath. Detailed Implementation

[0028] To better understand the technical content of this utility model, specific embodiments are provided below in conjunction with the accompanying drawings.

[0029] Combined with appendix Figure 1-4 As shown, the environmentally friendly mineral-insulated fire-resistant cable of this utility model aims to solve the problems of damage and gap defects in the overlapping area of ​​mica wrapping tape, including conductor core 10, fire-resistant layer 20, inner sheath 30 and outer sheath 40.

[0030] like Figure 1 and Figure 2 As shown, the conductor core 10 includes multiple stranded wires 11. The wires 11 can be made of fine copper wires twisted in a regular twisting manner for transmitting electrical energy.

[0031] The fire-resistant layer 20 is wrapped around the outside of the conductor core 10 to serve as a fire barrier.

[0032] The inner sheath 30 covers the outside of the fire-resistant layer 20. The inner sheath 30 can be made of corrugated copper strip. The corrugated copper strip is longitudinally wrapped around the outside of the fire-resistant layer 20, and the joints of the corrugated copper strip are welded and sealed. The corrugated (similar to a corrugated pipe) structure itself provides the possibility of bending. At the same time, the copper sheath after the corrugated copper strip is welded and formed provides sealing and mechanical protection functions.

[0033] The outer sheath 40 is extruded onto the outside of the inner sheath 30. The outer sheath 40 includes a halogen-free low-smoke polymer sheath. The halogen-free low-smoke polymer sheath does not release toxic hydrogen halide gas when burning, and at the same time has excellent physical properties and weather resistance, meeting environmental protection requirements.

[0034] As an optional embodiment, the fire-resistant layer 20 along the width direction includes a non-overlapping area 201 and overlapping areas 202 distributed on both sides of the non-overlapping area 201.

[0035] The thickness of the non-overlapping area 201 is set to twice the thickness of the overlapping area 202. During the wrapping process, the overlapping areas 202 are overlapped to make the thickness of the overlapping area 202 and the non-overlapping area 201 on the outside of the conductor core 10 the same after wrapping. In this way, the outer diameter of the entire fire-resistant layer 20 is almost unchanged, and the overlapping area and the non-overlapping area are smoothly transitioned.

[0036] Therefore, when the cable is bent, the overlap can be reduced, and the probability of damage and powder shedding at the edge of the mica sheet can be reduced.

[0037] like Figure 3 and Figure 4 As shown, the fire-resistant layer 20 includes two sets of composite mineral insulating tapes 21, which are bonded to each other in the overlap area 202 section.

[0038] In the non-overlapping section 201, a ceramicized silicone rubber filling structure 22 is provided between the two sets of composite mineral insulation tapes 21.

[0039] In the overlap area 202 section, the surfaces of the two sets of composite mineral insulation tapes 21 are provided with overlap fillers 23, and the two sets of overlap fillers 23 are centrally symmetrically distributed.

[0040] As an optional embodiment, the thickness of the overlap filler 23 is set to 1 / 2 of the thickness of the ceramicized silicone rubber filler structure 22.

[0041] Thus, during the wrapping process of the refractory layer 20, the overlapping areas 202 overlap each other, while the non-overlapping areas 201 adhere to the outside of the conductor core 10. The thickness of the overlapping areas 202 and the non-overlapping areas 201 on the outside of the conductor core 10 is basically the same, so that the outer diameter of the entire refractory layer 20 remains consistent and there are no obvious protrusions. This makes the sealing of the overlapping areas 202 better and will not squeeze the mica material, reducing the probability of damage and powdering at the edge of the mica sheet.

[0042] As an optional embodiment, in order to make the overlap wrapping of the overlap area 202 more precise, a positioning groove is provided on the mating surface of the overlap filler 23. The positioning groove is shaped as a concave-convex structure, such as a wave or sawtooth structure. The positioning grooves on the two overlap fillers 23 complement each other to complete the precise positioning of the overlap area 202.

[0043] As an optional embodiment, the overlap filler 23 uses a ceramicized silicone rubber strip. When burning, the ceramicized silicone rubber can be rapidly sintered into a hard, self-supporting ceramic body, preventing the flame from spreading to the mica tape and the interior, and maintaining structural integrity. It has strong thermal shock resistance, does not crack when exposed to water, and its combustion products are non-toxic and produce low smoke. Together with the mica tape, it enhances the fire safety and reliability of the cable.

[0044] As an optional embodiment, the composite mineral insulating tape 21 forms a cavity with a rectangular or parallelogram cross-section in the non-overlapping area 201 section, and the ceramicized silicone rubber filling structure 22 fills the cavity.

[0045] Therefore, in this embodiment, the ceramicized silicone rubber filling structure 22 and the overlapping filling 23 using ceramicized silicone rubber strips can cover the entire area in the axial direction. The ceramic body formed by the ceramicized silicone rubber during combustion, in conjunction with the mica tape, achieves excellent fire resistance.

[0046] Furthermore, the bonding area of ​​the composite mineral insulating tape 21 is centrally symmetrically distributed around the central axis of the cavity, which makes the overall outer diameter of the composite mineral insulating tape 21 tend to be consistent when the composite mineral insulating tape 21 is wrapped and overlapped, with no obvious protrusions.

[0047] As an optional embodiment, the composite mineral insulation tape 21 includes a mica layer 211 and a substrate layer 212, with the substrate layer 212 adhered to the inside of the mica layer 211.

[0048] As an optional embodiment, the substrate layers 212 can be adhered and fixed to each other. The substrate layers 212 are generally made of alkali-free fiberglass cloth, which provides tensile strength and prevents the strip from tearing, and is used to adhere mica sheets. The mica layer 211 can be made of phlogopite or muscovite sheets.

[0049] Specifically, the refractory layer 20 is formed by bonding two refractory layers together. The specific preparation method is as follows:

[0050] The preparation method of the single-layer fire-resistant layer is to first coat a layer of mortar of a certain width on the first side of the composite mineral insulating tape 21 in the width direction to form an overlap filler 23, and then coat the mortar of the above thickness in the middle area of ​​the second side of the composite mineral insulating tape 21 to form a ceramicized silicone rubber filling structure 22 with half the thickness, thus forming a single-layer fire-resistant layer.

[0051] Two layers of refractory-coated composite mineral insulating tape 21 are joined together on opposite sides, and the composite mineral insulating tape 21 is extruded through a die along its length to form... Figure 3 The cross-sectional shape shown is then passed through an oven to allow the solvent to evaporate completely, leaving a uniform ceramicized silicone rubber layer, thus forming a refractory layer 20. In addition, according to requirements, positioning grooves with a set concave-convex structure are formed on the surface of the overlapping filler 23 by embossing or scraping.

[0052] In an optional embodiment, the above-mentioned adhesive is prepared by first plasticizing the raw silicone rubber in a two-roll mill or internal mixer, and then adding fumed silica (reinforcing agent), structure control agent, ceramic filler, flux, flame retardant and other additives in sequence, and mixing thoroughly to ensure that all fillers and additives are dispersed extremely evenly in the rubber compound. After mixing, a uniform ceramicized silicone rubber compound is obtained. The above-mentioned mixed rubber compound is dissolved in a solvent (such as xylene) and stirred to make an adhesive with a certain viscosity. According to the required coating position on the composite mineral insulation tape 21, the adhesive is evenly coated on the substrate of glass fiber cloth and mica paper in operation by a precision coating machine.

[0053] In conjunction with the above embodiments, the environmentally friendly mineral-insulated fire-resistant cable of this embodiment uses ceramicized silicone rubber mica tape with thickness differences in the width direction. The middle area is set as a non-overlapping area 201, and the two sides are set as overlapping areas 202. The overlapping areas 202 are centrally symmetrically distributed. The ceramicized silicone rubber is located inside the sandwich between two mica layers 211 in the non-overlapping area 201, and outside the single mica layer 211 in the overlapping area 202. However, when the overlapping areas 202 are fully overlapped, the ceramicized silicone rubber is again located inside the two mica layers 211. While the ceramicized silicone rubber and mica sheets provide stable fire resistance performance, the entire fire-resistant layer 20 has almost no significant change in outer diameter. The overlapping area and the non-overlapping area transition smoothly. When the cable is bent, the overlap can be reduced and the probability of damage and powdering at the edge of the mica sheet can be reduced.

[0054] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Those skilled in the art to which this invention pertains can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of this invention shall be determined by the claims.

Claims

1. An environmentally friendly mineral-insulated fire-resistant cable, characterized in that, include: The conductor core (10) includes multiple twisted wires (11); A fire-resistant layer (20) is wrapped around the outside of the conductor core (10); The inner sheath (30) covers the outside of the fire-resistant layer (20); The outer sheath (40) is extruded over the outside of the inner sheath (30); The fire-resistant layer (20) along the width direction includes a non-overlapping area (201) and overlapping areas (202) distributed on both sides of the non-overlapping area (201). The thickness of the non-overlapping area (201) is set to twice the thickness of the overlapping area (202). During wrapping, the overlapping areas (202) are overlapped to make the thickness of the overlapping area (202) and the non-overlapping area (201) on the outside of the conductor core (10) the same after wrapping.

2. The environmentally friendly mineral-insulated fire-resistant cable according to claim 1, characterized in that, The fire-resistant layer (20) includes two sets of composite mineral insulating tapes (21), and the two sets of composite mineral insulating tapes (21) are bonded to each other in the overlapping area (202) section. In the non-overlapping area (201) section, a ceramicized silicone rubber filling structure (22) is provided between the two sets of composite mineral insulating tapes (21). In the overlapping area (202) section, the surfaces of the two sets of composite mineral insulating tapes (21) are provided with overlapping filler (23), and the two sets of overlapping filler (23) are centrally symmetrically distributed.

3. The environmentally friendly mineral-insulated fire-resistant cable according to claim 2, characterized in that, The thickness of the overlap filler (23) is set to 1 / 2 of the thickness of the ceramicized silicone rubber filler structure (22).

4. The environmentally friendly mineral-insulated fire-resistant cable according to claim 2, characterized in that, The overlapping filler (23) has a positioning groove on its bonding surface.

5. The environmentally friendly mineral-insulated fire-resistant cable according to claim 2, characterized in that, The overlap filler (23) includes a ceramicized silicone rubber strip.

6. The environmentally friendly mineral-insulated fire-resistant cable according to claim 2, characterized in that, The composite mineral insulating tape (21) forms a cavity with a rectangular or parallelogram cross-section in the non-overlapping area (201) section, and the ceramicized silicone rubber filling structure (22) fills the cavity.

7. The environmentally friendly mineral-insulated fire-resistant cable according to claim 6, characterized in that, The bonding area of ​​the composite mineral insulating tape (21) is centrally symmetrically distributed around the central axis of the cavity.

8. The environmentally friendly mineral-insulated fire-resistant cable according to claim 2, characterized in that, The composite mineral insulation tape (21) includes a mica layer (211) and a substrate layer (212). The substrate layer (212) is adhered to the inner side of the mica layer (211), and the substrate layers (212) can adhere and fix each other.

9. The environmentally friendly mineral-insulated fire-resistant cable according to claim 1, characterized in that, The inner sheath (30) includes a corrugated copper strip, which is longitudinally wrapped around the outside of the refractory layer (20), and the joints of the corrugated copper strip are welded and sealed.

10. The environmentally friendly mineral-insulated fire-resistant cable according to claim 1, characterized in that, The outer sheath (40) comprises a halogen-free low-smoke polymer sheath.

Images