Low smoke zero halogen crosslinked low shrinkage cable

Abstract

The utility model relates to the technical field of power cable, specifically low smoke halogen-free crosslinking low shrinkage cable, include: at least one core, the outer layer of core is equipped with the sheath layer, the core includes conductor, irradiation crosslinking polyolefin insulation layer and support layer, wherein, the support layer includes the cladding layer that the thin steel band is formed by longitudinal package to the irradiation crosslinking polyolefin insulation layer outside cladding, the utility model discloses the rigid constraint that thin steel band cladding layer provided in the outer layer of insulation layer directly and effectively resists the axial and radial shrinkage force that irradiation crosslinking insulation layer generates when heating, eliminates the risk of joint pulling and insulation peeling due to shrinkage from physical structure, and, the rough processing layer of thin steel band inner surface and insulation shield layer form mechanical anchoring, and this kind of mechanical interlocking structure ensures that support layer and insulation layer do not separate under thermal expansion and contraction and bending working condition, guarantee the durability of inhibiting shrinkage effect.

Description

Technical Field

[0001] This utility model relates to the field of power cable technology, and more specifically to low-smoke halogen-free cross-linked low-shrinkage cables. Background Technology

[0002] In industrial power distribution systems and building trunk lines that need to withstand long-term high operating temperatures or short-term overloads, irradiated cross-linked cables are widely used because their insulation layer forms a three-dimensional network structure through irradiation, which gives them excellent heat resistance and aging resistance.

[0003] However, this cross-linked polymer material has a thermal shrinkage memory effect when heated. This causes the insulation and sheath materials to shrink axially and radially when the cable temperature rises during actual operation, resulting in dimensional instability and reduced structural reliability due to cable thermal shrinkage. Utility Model Content

[0004] In view of the technical problems of connection point pulling, insulation peeling and partial discharge caused by thermal shrinkage in existing irradiated cross-linked cables, this utility model proposes a low-smoke halogen-free cross-linked low-shrinkage cable, which can effectively suppress thermal shrinkage deformation and maintain the long-term stability of the cable structure.

[0005] According to a first aspect of the present invention, a low-smoke, halogen-free, cross-linked, low-shrinkage cable is provided, comprising:

[0006] At least one conductor, with a sheath layer provided on the outer layer of the conductor;

[0007] The wire core includes a conductor, an irradiated cross-linked polyolefin insulation layer, and a support layer;

[0008] The support layer includes a covering layer formed by longitudinally wrapping a thin steel strip around the irradiated cross-linked polyolefin insulation layer. The inner surface of the thin steel strip has a roughening treatment layer to increase the bonding force between the covering layer and the surface of the irradiated cross-linked polyolefin insulation layer.

[0009] The roughening layer is configured as a groove structure formed by rubbing the surface of the thin steel strip in at least two directions using a sanding belt or wire brush and extending along the rubbing direction. The extending direction of the groove structure includes a first direction parallel to the length direction of the thin steel strip and a second direction inclined to the length direction of the thin steel strip.

[0010] Preferably, the thickness of the thin steel strip is 0.05 to 0.15 mm.

[0011] Preferably, the thickness of the roughening layer on the inner surface of the thin steel strip is 10-30% of the thickness of the thin steel strip.

[0012] Preferably, the roughness Ra of the inner surface of the thin steel strip is 3μm to 15μm.

[0013] Preferably, the longitudinal overlap of the thin steel strip is fixed by spot welding or conductive adhesive bonding.

[0014] Preferably, a conductive adhesive layer is provided between the coating layer and the irradiated cross-linked polyolefin insulating layer.

[0015] Preferably, the thin steel strip is a low-carbon steel strip or a stainless steel strip.

[0016] Preferably, the irradiated cross-linked polyolefin insulation layer comprises a three-layer co-extruded conductor shielding layer, an irradiated cross-linked polyethylene insulation layer, and an insulation shielding layer.

[0017] Preferably, the multiple cores are twisted together in pairs and wrapped with a sheath to form a cable core with a circular cross-section, and the sheath is extruded over the cable core.

[0018] Preferably, the sheath layer includes an inner sheath layer and an outer sheath layer, the inner sheath layer includes a silicone rubber sheath layer, and the outer sheath layer includes an irradiated cross-linked polyolefin sheath layer.

[0019] Compared with the prior art, the advantages of the low-smoke halogen-free cross-linked low-shrinkage cable proposed in this utility model are as follows:

[0020] The low-smoke halogen-free cross-linked low-shrinkage cable of this invention directly and effectively resists the axial and radial shrinkage forces generated when the irradiated cross-linked insulation layer is heated by the rigid constraint provided by the thin steel strip covering layer set on the outer layer of the insulation layer. It eliminates the risk of joint pulling and insulation peeling caused by shrinkage from the physical structure. In addition, the rough treatment layer on the inner surface of the thin steel strip forms a mechanical anchor with the insulation shielding layer. This mechanical interlocking structure ensures that the support layer and the insulation layer do not separate under thermal expansion and contraction and bending conditions, and guarantees the durability of the shrinkage suppression effect.

[0021] As mentioned above, by suppressing the shrinkage and peeling of the insulation layer from the conductor or shielding layer, the partial discharge problem caused by the formation of air gaps is effectively avoided, thereby extending the insulation life of the cable and improving the overall stability of the power supply network. Attached Figure Description

[0022] 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.

[0023] Figure 1 This is a schematic diagram of the structure of the low-smoke halogen-free cross-linked low-shrinkage cable shown in this utility model.

[0024] Figure 2This is a schematic diagram of the cross-sectional structure of the low-smoke halogen-free cross-linked low-shrinkage cable shown in this utility model.

[0025] Figure 3 This is a schematic diagram of the cross-sectional structure of the wire core shown in this utility model.

[0026] Figure 4 This is a schematic diagram of the structure of the thin steel strip shown in this utility model. Detailed Implementation

[0027] To better understand the technical content of this utility model, specific embodiments are provided below in conjunction with the accompanying drawings.

[0028] Combination Figure 1 As shown, the low-smoke halogen-free cross-linked low-shrinkage cable according to an embodiment of the present invention includes at least one conductor 1 and a sheath layer provided on the outer layer of the conductor 1.

[0029] The wire core 1 includes a conductor 11, an irradiated cross-linked polyolefin insulation layer, and a support layer 16.

[0030] As shown in the figure, in order to prevent the irradiated cross-linked polyolefin insulation layer from undergoing axial deformation after the cable temperature rises, the support layer 16 includes a covering layer formed by longitudinally wrapping a thin steel strip 161 around the irradiated cross-linked polyolefin insulation layer. The inner surface of the thin steel strip 161 has a roughening treatment layer 162 to increase the bonding force between the covering layer and the surface of the irradiated cross-linked polyolefin insulation layer.

[0031] It should be understood that the thin steel strip 161 itself has a high elastic modulus and tensile strength. When placed on the outer layer of the irradiated cross-linked polyolefin insulation layer, it can provide radial and axial binding forces to the insulation layer from the outside to resist its thermal shrinkage tendency.

[0032] In addition, the roughening layer 162 can increase the contact area and friction between the thin steel strip 161 and the irradiated cross-linked polyolefin insulation layer, thereby improving the bonding force and increasing the mechanical anchoring effect.

[0033] When the cable operating temperature rises and the insulation shielding material softens, it will partially embed into the grooves of the rough surface, forming a mechanical interlock. This greatly enhances the interlayer bonding force and prevents the support layer and insulation layer from slipping relative to each other due to their different coefficients of thermal expansion, thus ensuring the integrity and dimensional stability of the cable structure.

[0034] It should be understood that if the thickness of the thin steel strip 161 is less than 0.05 mm, the rigidity of the steel strip is insufficient to effectively provide the mechanical strength required for shrinkage resistance, while if the thickness of the thin steel strip 161 is too thick, it will result in high cable stiffness.

[0035] In an optional embodiment, the thickness of the thin steel strip 161 is 0.05 to 0.15 mm.

[0036] Furthermore, if the roughness or scratch depth of the roughening layer 162 is too small, for example Ra < 3 μm or depth < 10%, the mechanical anchoring effect will not be obvious; if it is too large, Ra > 15 μm or depth > 30%, stress concentration points may be formed on the surface of the steel strip, potentially affecting its long-term mechanical integrity.

[0037] Therefore, preferably, the thickness of the roughening layer 162 on the inner surface of the thin steel strip 161 is 10% to 30% of the thickness of the thin steel strip. The roughness Ra of the inner surface of the thin steel strip 161 is 3 μm to 15 μm.

[0038] The roughening layer 162 can be formed by sanding with a sanding belt or a wire brush on the surface of the thin steel strip 161.

[0039] Specifically, the roughening layer 162 is configured as a groove structure formed by friction treatment on the surface of the thin steel strip 161 in at least two directions by sanding belt or wire brush and extending along the friction direction. The extension direction of the groove structure includes a first direction parallel to the length direction of the thin steel strip 161 and a second direction inclined to the length direction of the thin steel strip 161.

[0040] Thus, the resulting groove structure has frictional forces in multiple directions to increase the bonding force with the insulating shielding layer 3.

[0041] In a preferred embodiment, the thin steel strip 161 is a low-carbon cold-rolled steel strip with a thickness of 0.08 mm. After longitudinal wrapping, its overlap width is 5 mm and it is fixed by spot welding. The inner surface of the thin steel strip 161 is mechanically ground (the first direction is the length direction of the thin steel strip 161, and the second direction is a 30° angle direction inclined to the length direction of the thin steel strip 161), and its surface roughness Ra is 8 μm, thereby forming a tight mechanical bond with the insulating shielding layer 3.

[0042] Furthermore, the thickness of the thin steel strip 161 can be selected between 0.05mm and 0.15mm. When there are special requirements for corrosion resistance, the cladding layer 161 can be made of stainless steel strip, and the outer surface of the thin steel strip 161 can be provided with a galvanized anti-corrosion layer.

[0043] In other embodiments, the anti-corrosion coating may be an epoxy resin layer.

[0044] In a preferred embodiment, the longitudinal overlap of the thin steel strip 161 is fixed by spot welding or adhesive bonding.

[0045] Furthermore, a conductive adhesive layer 15 is provided between the coating layer and the irradiated cross-linked polyolefin insulating layer.

[0046] Thus, the conductive adhesive layer 15 can completely fill the microscopic gaps between the surface of the thin steel strip 161 and the insulating shielding layer, forming better interfacial contact and further reducing the possibility of partial discharge. At the same time, the conductive adhesive layer 15 provides additional adhesive force, which, together with the mechanical anchoring effect, further enhances the interlayer bonding strength.

[0047] In an optional embodiment, the irradiated cross-linked polyolefin insulation layer includes a three-layer co-extruded conductor shielding layer 12, an irradiated cross-linked polyethylene insulation layer 13, and an insulating shielding layer 14.

[0048] In optional embodiments, this invention is also applicable to multi-core cables. Specifically, multiple cores 1 are twisted tangentially in pairs and wrapped by a sheath 3 to form a cable core with a circular cross-section, and the sheath layer is extruded around the cable core.

[0049] Furthermore, the sheath layer includes an inner sheath layer 4 and an outer sheath layer 5. The inner sheath layer 4 includes a silicone rubber sheath layer, and the outer sheath layer 5 includes an irradiated cross-linked polyolefin sheath layer.

[0050] Thus, the inner sheath layer 4, made of silicone rubber, possesses excellent flexibility, elasticity, and thermal insulation properties, providing cushioning protection for the internal cable core and isolating external heat to a certain extent. Meanwhile, the outer sheath layer 5, made of irradiated cross-linked polyolefin, offers superior mechanical protection, abrasion resistance, and weather resistance.

[0051] The aforementioned composite sheath structure enhances the overall durability of the cable and its adaptability to complex environments.

[0052] 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. A low-smoke, halogen-free, cross-linked, low-shrinkage cable, characterized in that include: At least one wire core (1) is provided with a sheath layer on the outer layer of the wire core (1); The wire core (1) includes a conductor (11), an irradiated cross-linked polyolefin insulation layer, and a support layer (16); The support layer (16) includes a covering layer formed by longitudinally wrapping a thin steel strip (161) over the irradiated cross-linked polyolefin insulation layer. The inner surface of the thin steel strip has a roughening treatment layer (162) to increase the bonding force between the covering layer and the surface of the irradiated cross-linked polyolefin insulation layer. The roughening layer (162) is configured as a groove structure formed by friction treatment on the surface of the thin steel strip (161) in at least two directions by sanding belt or wire brush and extending along the friction direction. The extension direction of the groove structure includes a first direction parallel to the length direction of the thin steel strip (161) and a second direction inclined to the length direction of the thin steel strip (161).

2. The low-smoke halogen-free cross-linked low-shrinkage cable according to claim 1, characterized in that, The thickness of the thin steel strip (161) is 0.05 to 0.15 mm.

3. The low-smoke halogen-free cross-linked low-shrinkage cable according to claim 1, characterized in that, The thickness of the roughening layer (162) on the inner surface of the thin steel strip (161) is 10 to 30% of the thickness of the thin steel strip.

4. The low-smoke halogen-free cross-linked low-shrinkage cable according to claim 1, characterized in that, The surface roughness Ra of the inner surface of the thin steel strip (161) is 3μm to 15μm.

5. The low-smoke halogen-free cross-linked low-shrinkage cable according to claim 1, characterized in that, The longitudinal overlap of the thin steel strip (161) is fixed by spot welding or conductive adhesive bonding.

6. The low-smoke halogen-free cross-linked low-shrinkage cable according to claim 1, characterized in that, A conductive adhesive layer (15) is provided between the coating layer and the irradiated cross-linked polyolefin insulating layer.

7. The low-smoke halogen-free cross-linked low-shrinkage cable according to claim 1, characterized in that, The thin steel strip is a low-carbon steel strip or a stainless steel strip.

8. The low-smoke halogen-free cross-linked low-shrinkage cable according to claim 1, characterized in that, The irradiated cross-linked polyolefin insulation layer comprises a three-layer co-extruded conductor shielding layer (12), an irradiated cross-linked polyethylene insulation layer (13), and an insulation shielding layer (14).

9. The low-smoke halogen-free cross-linked low-shrinkage cable according to any one of claims 1-8, characterized in that, Multiple cores (1) are twisted together in pairs and wrapped by a sheath (3) to form a cable core with a circular cross-section. The sheath is extruded over the cable core.

10. The low-smoke halogen-free cross-linked low-shrinkage cable according to claim 9, characterized in that, The sheath layer includes an inner sheath layer (4) and an outer sheath layer (5). The inner sheath layer (4) includes a silicone rubber sheath layer, and the outer sheath layer (5) includes an irradiated cross-linked polyolefin sheath layer.

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