A class a control cable with cold resistance of minus 40 degrees celsius

Abstract

The utility model belongs to control cable technical field relates to a kind of zero 40 ℃ cold-resistant flame-retardant A class control cable, from inside to outside sequentially include cable core, cable core tape layer, shielding layer, inner liner, armoring layer and outer sheath;Cable core is twisted by flame-retardant insulation single wire and filling material, and flame-retardant insulation single wire is composed of a layer of flame-retardant insulation layer extruded outside conductor;Flame-retardant insulation layer is extruded by the flame-retardant polyvinyl chloride insulation material of oxygen index 32;Inner liner is extruded by the flame-retardant polyvinyl chloride sheath material of oxygen index 32;Outer sheath is made of the flame-retardant polyvinyl chloride sheath material of oxygen index 32 that can resist cold-40 ℃.Ensure that cable can pass flame-retardant A class bunch burning test, cable bunch burns carbonization height does not exceed 1 meter, the low-temperature tensile and low-temperature bending performance of outer sheath meet-40 ℃ low-temperature requirement, solve the application environment and construction period limit to cable, promote the upgrading of product, production efficiency is improved, simple structure, low in production cost.

Description

Technical Field

[0001] This utility model belongs to the field of control cable technology, specifically relating to a Class A control cable that is cold-resistant and flame-retardant at -40℃. Background Technology

[0002] With economic development and urbanization, the number of infrastructure projects in power, construction, and transportation is increasing, leading to a steady upward trend in the flame-retardant cable market and continuous expansion of its scale. Control cables, as key components for transmitting control signals and electrical energy, directly impact the reliability of the entire system. The increasing demands for electrical system reliability across various sectors, coupled with increasingly stringent cable application environments, have created a growing need for highly flame-retardant and cold-resistant control cables. This necessitates improving the flame-retardant and mechanical properties of cables, as well as their low-temperature resistance to adapt to harsher working environments.

[0003] For polyvinyl chloride (PVC) materials, flame retardancy and cold resistance are difficult to balance; higher flame retardancy generally results in lower cold resistance. Existing cold-resistant PVC-insulated and PVC-sheathed control cables can meet the Class B flame retardancy requirement for bundled combustion at -40℃, but Class A flame retardant PVC-insulated and PVC-sheathed control cables only meet the -15℃ cold resistance requirement, making it impossible to simultaneously satisfy both flame retardancy and cold resistance requirements.

[0004] Existing flame-retardant PVC sheathing materials are classified according to their flame-retardant rating into three categories: Flame-retardant Class C PVC sheathing materials (typically with an oxygen index of 28 or 30), Flame-retardant Class B PVC sheathing materials (typically with an oxygen index of 32), and Flame-retardant Class A PVC sheathing materials (typically with an oxygen index of 38). The cost difference between these different oxygen indices is significant, especially the cost of PVC sheathing materials with an oxygen index of 38, which can be tens of thousands of yuan more per ton than those with an oxygen index of 32. Therefore, to optimize cable costs while ensuring flame-retardant performance, a comprehensive consideration of the performance and cost of various materials is necessary. Utility Model Content

[0005] The purpose of this invention is to provide a Class A control cable that is cold-resistant and flame-retardant at -40℃, which solves the problem that the cold resistance performance of Class A flame-retardant control cables cannot meet the requirements of -40℃.

[0006] This utility model is achieved through the following technical solution: This utility model discloses a Class A control cable that is cold-resistant and flame-retardant at -40℃, which includes, from the inside out, a cable core, a cable core wrapping layer, a shielding layer, an inner lining layer, an armor layer, and an outer sheath. The cable core is made of flame-retardant insulated single wires twisted together with filler material, and the flame-retardant insulated single wires are composed of a conductor with a flame-retardant insulation layer extruded on the outside; The flame-retardant insulation layer is extruded from flame-retardant polyvinyl chloride insulation material with an oxygen index of 32. The inner lining is extruded from flame-retardant polyvinyl chloride sheath material with an oxygen index of 32. The outer sheath is made of flame-retardant polyvinyl chloride sheath material with an oxygen index of 32 that can withstand temperatures as low as -40°C.

[0007] Furthermore, the conductor is a single or stranded conductor.

[0008] Furthermore, the conductor material is pure copper or tin-plated copper.

[0009] Furthermore, the filling material is composed of flame-retardant polypropylene filling rope.

[0010] Furthermore, the cable core wrapping layer is made of polyester film overlapped and wrapped around the outside of the cable core.

[0011] Furthermore, the shielding layer is composed of overlapping metal strips or woven metal wires.

[0012] Furthermore, the shielding layer is made of pure copper strip, copper / plastic composite strip, aluminum / plastic composite strip, pure copper wire, or tin-plated copper wire.

[0013] Furthermore, the armor layer is steel strip armor or steel wire armor.

[0014] Compared with the prior art, the present invention has the following beneficial technical effects: This utility model discloses a Class A control cable with cold resistance and flame retardancy down to -40℃. Traditional Class A flame retardant control cables have an oxygen index of 38 for their PVC insulation and PVC sheath, achieving Class A flame retardancy, but their cold resistance only meets the requirements for -15℃, not -40℃. This utility model uses a flame retardant PVC sheath material with an oxygen index of 32 for the outer sheath, which can withstand temperatures down to -40℃. However, this would prevent the flame retardancy from meeting Class A requirements. Therefore, the flame retardant insulation layer is designed to be extruded from flame retardant PVC insulation material with an oxygen index of 32, and the inner lining layer is extruded from flame retardant PVC sheath material with an oxygen index of 32. This improves the flame retardancy and ensures that the cable can pass the Class A bundled burning test. The char height of the bundled cable does not exceed 1 meter. The low-temperature tensile and low-temperature bending properties of the outer sheath meet the -40℃ low-temperature requirements. This solves the limitations of cable application environment and construction period, promotes product upgrading, improves production efficiency, simplifies the structure, and reduces production costs. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the control cable structure of this utility model.

[0016] The following numbers are labeled in the diagram: 1. Flame-retardant insulated single wire; 11. Conductor; 12. Flame-retardant insulation layer; 2. Filler material; 3. Cable core; 4. Cable core wrapping layer; 5. Shielding layer; 6. Inner lining layer; 7. Armoring layer; 8. Outer sheath. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this utility model clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this utility model and are not intended to limit it; that is, the described embodiments are only a part of, and not all, of the embodiments of this utility model.

[0018] The components described and illustrated in the accompanying drawings and embodiments of this utility model can be arranged and designed in various different configurations. Therefore, the detailed description of the embodiments of this utility model provided in the following drawings is not intended to limit the scope of the claimed utility model, but merely to illustrate one selected embodiment of the utility model. All other embodiments obtained by those skilled in the art based on the accompanying drawings and embodiments of this utility model without inventive effort are within the protection scope of this utility model.

[0019] It should be noted that the terms “comprising,” “including,” or any other variations are intended to cover non-exclusive inclusion, such that a process, element, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to the process, element, method, article, or apparatus.

[0020] The features and performance of this utility model will be further described in detail below with reference to the embodiments.

[0021] like Figure 1 As shown, this utility model proposes a Class A control cable that is cold-resistant and flame-retardant at -40℃, which includes, from the inside out, a cable core 3, a cable core wrapping layer 4, a shielding layer 5, an inner lining layer 6, an armor layer 7, and an outer sheath 8.

[0022] The cable core 3 is formed by twisting together flame-retardant insulated single wires 1. The flame-retardant insulated single wires 1 are filled with filling material 2, which is composed of flame-retardant polypropylene filling rope to ensure that the cable core 3 is round.

[0023] The flame-retardant insulated single wire 1 is composed of a conductor 11 with a flame-retardant insulation layer 12 extruded on it. The flame-retardant polyvinyl chloride insulation material of the flame-retardant insulation layer 12 has an oxygen index of 32.

[0024] The conductor 11 is a single or stranded conductor, and the conductor 11 is made of tin-plated conductor or non-tin-plated conductor.

[0025] The cable core wrapping layer 4 is composed of overlapping polyester films.

[0026] The shielding layer 5 is composed of overlapping and wrapping metal strips or woven metal wires; specifically, the material of the metal strip shielding layer is pure copper strip, copper / plastic composite strip, or aluminum / plastic composite strip, and the thickness of the metal strip is 0.05mm; when the shielding layer is woven with metal wires, the metal wires are tin-plated copper wires or non-tin-plated copper wires, and the diameter of the copper wires is 0.12mm to 0.3mm. The inner lining layer 6 is extruded from flame-retardant polyvinyl chloride sheath material with an oxygen index of 32, and has a thickness of not less than 1.0 mm or 1.2 mm.

[0027] The armor layer 7 is steel strip armor or steel wire armor, the steel strip is galvanized steel strip, and the steel strip thickness is 0.2mm or 0.5mm.

[0028] The outer sheath 8 is made of flame-retardant polyvinyl chloride extruded with an oxygen index of 32, ensuring that the cable's cold resistance can reach -40℃. The thickness of the outer sheath 8 is not less than 2.0mm.

[0029] A combustion test was conducted on the -40℃ cold-resistant and flame-retardant Class A control cable prepared according to this invention. The char height of the Class A flame-retardant bundled combustion test of the cable was no more than 1m.

[0030] The -40℃ cold-resistant and flame-retardant Class A control cable prepared according to this utility model was subjected to a low-temperature tensile test at -40℃. The low-temperature tensile strength of the cable outer sheath at -40℃ was not less than 25%, and the low-temperature bending of the cable outer sheath at -40℃ did not crack.

[0031] This invention improves the flame-retardant properties of the insulation while reducing the flame-retardant rating of the sheath material, resulting in a -40℃ flame-retardant Class A PVC insulated and PVC sheathed armored control cable. This control cable boasts excellent overall flame-retardant performance, extreme cold resistance, simple structure, ease of installation and use, low production cost, and simple manufacturing process. Furthermore, it balances the cable's flame-retardant and cold-resistant properties, simultaneously satisfying both requirements without altering the control cable's structure.

[0032] Existing cable standards stipulate that the construction temperature for control cables should not be lower than 0℃. However, in practical applications, due to construction schedule requirements, the construction temperature can reach -15℃ to -20℃. Furthermore, the low-temperature resistance performance of cables refers to the ambient temperature during normal operation. The cold resistance performance of cables is mainly evaluated through the low-temperature resistance of the cable sheath; however, these tests are static and do not reflect real-world construction conditions. Therefore, it is necessary to design a cable low-temperature performance testing plan.

[0033] GB / T 9330-2020 standard stipulates that the methods for low-temperature bending test, low-temperature tensile test, and low-temperature impact test shall comply with the provisions of GB / T 2951.14-2008 standard. GB / T 2951.14-2008 specifies the methods for low-temperature winding, low-temperature tensile, and low-temperature impact tests. It does not specify a method for low-temperature bending test. YD / T 1092-2013 specifies a method for low-temperature bending. The low-temperature bending test was conducted in accordance with YD / T1092-2013. The minimum bending radius of the cable was 12D, where D is the outer diameter of the cable. Using H40-ZA-KVVP2-22 450 / 750V 8×1.5 (B) as an example, with an outer diameter of 16.8 mm and a bending radius of 203 mm, the same H40-ZA-KVVP2-22450 / 750V 8×1.5 (B) cable was divided into 6 samples of equal length. Each sample was coiled twice to fix it, and then placed in a low-temperature chamber for the low-temperature bending test. The parameters for the low-temperature bending test are shown in the table below.

[0034] H40-ZA-KVVP2-22 450 / 750V 8×1.5 (B) Low Temperature Bending Test

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and not to limit it. Although the utility model has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of this utility model. Any modifications or equivalent substitutions that do not depart from the spirit and scope of this utility model should be covered within the protection scope of this utility model.

Claims

1. A Class A control cable with cold resistance and flame retardancy down to -40℃, characterized in that, From the inside out, it includes the cable core (3), the cable core wrapping layer (4), the shielding layer (5), the inner lining layer (6), the armor layer (7), and the outer sheath (8); The cable core (3) is made of flame-retardant insulated single wire (1) and filling material (2) twisted together. The flame-retardant insulated single wire (1) is composed of a conductor (11) with a flame-retardant insulation layer (12) extruded on the outside. The flame-retardant insulation layer (12) is extruded from flame-retardant polyvinyl chloride insulation material with an oxygen index of 32; The inner lining (6) is extruded from flame-retardant polyvinyl chloride sheath material with an oxygen index of 32; The outer sheath (8) is made of flame-retardant polyvinyl chloride sheath material with an oxygen index of 32 that can withstand temperatures as low as -40°C.

2. The Class A control cable with cold resistance and flame retardancy down to -40℃ as described in claim 1, characterized in that, The conductor (11) is a single or stranded conductor.

3. The Class A control cable with cold resistance and flame retardancy down to -40℃ as described in claim 1, characterized in that, The conductor (11) is made of pure copper or tin-plated copper.

4. The Class A control cable with cold resistance and flame retardancy down to -40℃ as described in claim 1, characterized in that, The filling material (2) is composed of flame-retardant polypropylene filling rope.

5. The Class A control cable with cold resistance and flame retardancy down to -40℃ as described in claim 1, characterized in that, The cable core wrapping layer (4) is made of polyester film overlapping and wrapped around the outside of the cable core.

6. The Class A control cable with cold resistance and flame retardancy down to -40℃ as described in claim 1, characterized in that, The shielding layer (5) is composed of overlapping metal strips or woven metal wires.

7. The Class A control cable with cold resistance and flame retardancy down to -40℃ as described in claim 1, characterized in that, The material of the shielding layer (5) is pure copper strip, copper / plastic composite strip, aluminum / plastic composite strip, pure copper wire or tin-plated copper wire.

8. The Class A control cable with cold resistance and flame retardancy down to -40℃ as described in claim 1, characterized in that, The armor layer (7) is steel strip armor or steel wire armor.

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