High-strength flexible cable and production process thereof

Abstract

The invention discloses a high-strength flexible cable. The high-strength flexible cable is characterized by comprising main cable cores, a filling layer, an inner sheath, an armor layer and an outer sheath, each of the three main wire cores is sequentially provided with a conductor and a conductor insulating layer from inside to outside along the radial direction of each main wire core; the conductor is formed by positively and negatively twisting a plurality of five-type tin-plated conductors, the pitch diameter ratio of a plied yarn is small, and the pitch diameter ratio of an inner layer is smaller than that of an outer layer during compound twisting; the conductor insulating layer is formed by extruding and coating XLPE on the outer part of the conductor; the filling layer comprises three filling strips, and the three filling strips are the same in structure and are all made of halogen-free rubber; the inner sides of the cross sections of the three filling strips are attached to the two adjacent main wire cores, and the outer sides of the cross sections of the three filling strips and the main wire cores form a whole circle. The three main wire cores and the three filling strips are twisted to form a cable core. The inner sheath is a composite inner sheath; the inner sheath is extruded outside the cable core; the armor layer is formed by weaving metal wires outside the inner sheath, and the weaving coverage rate is not less than 90%; and the outer sheath is extruded outside the armor layer by adopting polyolefin.

Description

Technical Field

[0001] The invention relates to the technical field of power cables, in particular to a high-strength flexible cable and a production process thereof. Background Art

[0002] Marine cables refer to wires and cables used for power, lighting, control, communication, microcomputer and other systems of various ships, offshore oil platforms and water buildings. Due to the harsh environmental conditions, the cables are required to be safe and reliable, have a long life, be small in size, be light in weight, and have excellent heat resistance, fire resistance, flame retardancy, oil resistance, moisture resistance, seawater resistance, and excellent electrical and mechanical properties. Marine power cables are a type of marine cables. Sometimes, due to the limitations of the use space, the cables need to have a certain degree of flexibility to facilitate bending and laying. Chinese patent document CN201868131U discloses a reinforced ship-use soft cable. When the cable uses a high-performance aramid material with a certain cross-sectional area as a reinforcing core, the aramid material has the characteristics of low density, high strength, low elongation, low hygroscopicity, and flame retardancy, so that the softness and torsion resistance of the cable are greatly improved, the outer diameter is smaller, which is 30% of the steel cable signal cable, and the weight is lighter, which is 40% of the steel cable signal cable. Due to the reduction of deadweight, the safety of the cable is more reliable under the same breaking force. The structure has good flexibility, but its tensile and compressive resistance needs to be improved. Chinese patent document CN102867578A discloses a cable consisting of a tinned copper conductor, an insulating layer, an insulating shielding layer, a filler, a sheath, a copper wire braided layer and an outer sheath. An insulating layer is extruded on a single tinned copper conductor, an insulating shielding layer is wrapped on the insulating layer to form a core, a filler is filled between multiple cores, a sheath is wrapped around the filler, a copper wire braided layer is woven on the sheath, and an outer sheath is extruded on the copper wire braided layer. The use of soft materials for the insulation allows the cable to have a minimum bending inner radius of 4 times the outer diameter of the cable during laying, which can save a lot of space for ship use, and its tensile and compressive resistance still needs to be improved. Summary of the invention

[0003] The object of the present invention is to provide a high-strength flexible cable with simple structure, good flexibility, tensile and compressive resistance and a production process thereof.

[0004] The basic technical scheme for achieving the purpose of the present invention is: a high-strength flexible cable, the structural characteristics of which are: comprising a main core, a filling layer, an inner sheath, an armor layer and an outer sheath; there are three main cores, and the structures of the three main cores are the same; the three main cores are provided with conductors and conductor insulation layers in sequence from the inside to the outside along their respective radial directions; the conductor is formed by twisting a number of five types of tinned conductors in reverse, and the strands have a small pitch diameter ratio, and the inner layer pitch diameter ratio is smaller than the outer layer pitch diameter ratio during re-twisting; the conductor insulation layer is coated on the conductor with XLPE extrusion An XLPE insulation layer is formed on the outside of the cable; the filling layer includes 3 filling strips, which have the same structure and are all made of halogen-free rubber; the inner side of the cross section of the 3 filling strips fits with the two adjacent main cores, and the outer side forms a full circle with the main cores; the 3 main cores and 3 filling strips are twisted into a cable core; the inner sheath is a composite inner sheath; the inner sheath is extruded outside the cable core; the armor layer is woven with metal wire outside the inner sheath, and the braiding coverage is not less than 90%; the outer sheath is extruded with polyolefin outside the armor layer.

[0005] In order to further improve the tensile strength, the inner sheath includes a first sheath layer, a wrapping layer and a second sheath layer; the first sheath layer is made of thermoplastic polyolefin extruded on the outside of the cable core twisted from 3 main cores and 3 filling strips, and the wrapping layer is made of composite metal ribbon wrapped around the first sheath layer, with a wrapping overlap rate of 2% to 5%; the second sheath layer is made of thermoplastic polyolefin extruded on the outside of the wrapping layer.

[0006] A production process for a high-strength flexible cable, characterized in that it comprises the following steps: Step 1: Use a number of Category 5 tinned conductors to twist forward and reverse to form the conductor of the main core, and the twisting pitch multiple is 10 to 14 times; use a small strand pitch ratio, the strand pitch ratio is 23 to 25, the inner layer pitch ratio is smaller than the outer layer pitch ratio during re-twisting, and the pitch ratio is 10 to 15 during re-twisting; Step 2: Extruding XLPE outside the conductor to form a conductor insulation layer to make a main line core; Step 3: Use halogen-free rubber to extrude a filling strip, the inner side of the cross section of the filling strip fits with the two adjacent main line cores, and the outer side forms a full circle with the main line core; Step 4: 3 main wire cores and 3 filling strips are twisted into a cable core; Step 5, making the inner sheath, firstly connecting the first extruder, the wrapping machine, the high temperature pipe and the second extruder in series in sequence; 1. The first extruder is used to extrude thermoplastic polyolefin onto the cable core formed by twisting three main cores and three filling strips to form the first sheath layer; the extrusion pressure is 10 MPa to 30 MPa, and the extrusion temperature is 115 degrees to 145 degrees; 2. After extrusion, the first sheath layer is kept at 115 to 145 degrees, and then the composite metal ribbon is wrapped around the first sheath layer by a wrapping machine to form a wrapping layer, so that the wrapping layer is pre-bonded and fixed to the first sheath layer; 3. Heating through high-temperature pipes to a temperature ranging from 120 to 145 degrees; 4. The polyolefin is extruded outside the wrapping layer by a second extruder to form a second sheath layer. The extrusion pressure is higher than that of the first extruder, and the extrusion pressure is 40 MPa to 50 MPa. The extrusion temperature is higher than that of the first extruder, and the extrusion temperature is 130 degrees to 160 degrees, so that the first sheath layer, the wrapping layer and the second sheath layer form a composite sheath layer; Step 6: Weave the metal wire outside the inner sheath to form an armor layer, and the weaving coverage rate is not less than 90%; Step seven, extruding polyolefin on the outside of the armor layer to form an outer sheath.

[0007] The present invention has the following beneficial effects: (1) The high-strength flexible cable of the present invention has excellent bendability. The conductor design structure and high-flexibility XLPE insulation material used enable the cable to maintain good performance even in a frequently bent use environment. The conductor usually has a large strand pitch-diameter ratio. When re-twisted, the inner layer pitch-diameter ratio is greater than the outer layer pitch-diameter ratio. This ensures that the overall twisting rate of the cable is small, but the conductor is easily deformed when passing through multiple devices. The high-strength flexible cable conductor of the present invention has a small strand pitch-diameter ratio. When re-twisted, the inner layer pitch-diameter ratio is smaller than the outer layer pitch-diameter ratio, which makes the cable more rounded and ensures that the conductor is not easily deformed after passing through multiple production equipment.

[0008] (2) The conductor of the high-strength flexible cable of the present invention is made of multiple strands of finely twisted soft copper wires, which increases the flexibility of the conductor. At the same time, the twisting pitch of the conductor is reasonably controlled to ensure that there will be no problems such as broken strands when bending.

[0009] (3) The XLPE insulation material of the high-strength flexible cable of the present invention has high elasticity and low hardness and can withstand repeated bending without cracking or damage.

[0010] (3) The inner sheath of the high-strength flexible cable of the present invention is a composite inner sheath, and a wrapping layer is provided between the first sheath layer and the second sheath layer, which are bonded and fixed together, thereby facilitating the improvement of the tensile and compressive resistance of the cable and effectively protecting the internal structure of the cable from damage by external pressure.

[0011] (4) The high-strength flexible cable of the present invention is provided with an armor layer, which can enhance the overall compressive resistance of the cable and prevent the cable from being deformed or damaged when subjected to external pressure.

[0012] (5) The outer sheath of the high-strength flexible cable of the present invention has good aging resistance and environmental stress cracking resistance. During long-term use, it can resist cracking caused by factors such as temperature changes, ultraviolet radiation, and chemical corrosion.

[0013] (6) The production process of the high-strength flexible cable of the present invention is simple. The first extruder, the wrapping machine, the high-temperature pipe and the second extruder are connected in series in sequence to realize the processing of the composite sheath layer. The structure is firm and the integrity is good, which is conducive to improving the tensile strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic structural diagram of the high-strength flexible cable of the present invention.

[0015] The reference numerals in the accompanying drawings are: Main line core 1, conductor 1-1, conductor insulation layer 1-2, Filling layer 2, Inner sheath 3, first sheath layer 3-1, wrapping layer 3-2, second sheath layer 3-3, Armor layer 4, Outer sheath 5. DETAILED DESCRIPTION

[0016] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments and in conjunction with the accompanying drawings. Figure 1 The direction shown is carried out, that is, Figure 1 The up, down, left, and right directions shown are the up, down, left, and right directions described. Figure 1 The direction is forward, away from Figure 1 The side that is closer to the other side is the rear side. Terms such as "upper", "lower", "inner", "outer", etc. indicating directions or positional relationships are based on the positional relationships described in the drawings and are only for the convenience of describing the present invention or simplifying the description, rather than indicating a specific direction that must be possessed. In the description of the present invention, terms such as "first", "second", etc. are only used to distinguish descriptions and cannot be understood as indicating or implying relative importance.

[0017] (Example 1) See Figure 1 The high-strength flexible cable of the present invention comprises a main core 1, a filling layer 2, an inner sheath 3, an armor layer 4 and an outer sheath 5. There are three main cores 1, and the three main cores 1 have the same structure. The three main cores 1 are provided with conductors 1-1 and conductor insulation layers 1-2 in sequence from the inside to the outside along their respective radial directions.

[0018] Conductor 1-1 is made of several Category 5 tinned conductors twisted forward and reversely, with a pitch multiple of 10 to 14 times. The strand pitch diameter ratio is small, with a strand pitch diameter ratio of 23 to 25. When twisted again, the inner layer pitch diameter ratio is smaller than the outer layer pitch diameter ratio, and the pitch diameter ratio is 10 to 15 during twisting, so that the cable has higher roundness and ensures that the conductor is not easily deformed after passing through multiple production equipment.

[0019] The conductor insulation layer 1-2 is formed by extruding XLPE and wrapping the conductor 1-1 to form an XLPE insulation layer. The filling layer 2 includes three filling strips, which have the same structure and are all made of halogen-free rubber. The inner sides of the cross-sections of the three filling strips fit the two adjacent main cores 1, and the outer sides thereof form a full circle with the main core 1.

[0020] Three main line cores 1 and three filling strips 2 are twisted into a cable core, and the filling strips 2 make the cable core more round and stable after being cabled.

[0021] The inner sheath 3 is a composite inner sheath, and the inner sheath 3 includes a first sheath layer 3-1, a wrapping layer 3-2 and a second sheath layer 3-3. The first sheath layer 3-1 is made of thermoplastic polyolefin and is wrapped around the cable core formed by twisting three main cores 1 and three filling strips 2. The wrapping layer 3-2 is made of composite metal ribbon wrapped around the first sheath layer 3-1, and the wrapping overlap rate is 2% to 5%. The composite metal ribbon is copper wire interlaced on a semi-conductive tape and is directly purchased on the market. The second sheath layer 3-3 is made of thermoplastic polyolefin and is extruded outside the wrapping layer 3-2.

[0022] The armor layer 4 is woven on the outside of the inner sheath 3 with metal wires, and in this embodiment, steel wires are woven on the outside of the inner sheath 3, with a weaving coverage of not less than 90%, and in this embodiment, 92%.

[0023] The outer sheath 5 is extruded and wrapped around the armor layer 4 using polyolefin.

[0024] The production process of the above-mentioned high-strength flexible cable includes the following steps: Step 1: Use a number of Category 5 tinned conductors to twist forward and reversely to form the conductor 1-1 of the main core 1, and the twisting pitch multiple is 10 to 14 times; use a small strand pitch ratio, the strand pitch ratio is 23 to 25, the inner layer pitch ratio is smaller than the outer layer pitch ratio during re-twisting, and the pitch ratio is 10 to 15 during re-twisting, so that the cable has a higher roundness and ensures that the conductor is not easily deformed after passing through multiple production equipment; Step 2: Extruding XLPE outside the conductor 1-1 to form a conductor insulation layer 1-2 to make a main line core 1; Step 3: extrude a filling strip 2 using halogen-free rubber, wherein the inner side of the cross section of the filling strip 2 is in contact with two adjacent main line cores 1, and the outer side of the filling strip 2 forms a full circle with the main line core 1; Step 4, three main line cores 1 and three filling strips 2 are twisted into a cable core; Step five, making the inner sheath 3, firstly connect the first extruder, the wrapping machine, the high-temperature pipeline and the second extruder in series in sequence.

[0025] 1. Extruding thermoplastic polyolefin onto the cable core formed by twisting three main cores 1 and three filling strips 2 by a first extruder to form a first sheath layer 3-1; the extrusion pressure is 10 MPa to 30 MPa, 14 MPa in this embodiment, and the extrusion temperature is 115 to 145 degrees, 125 degrees in this embodiment; 2. After extrusion, the first sheath layer 3-1 is kept at 115 to 145 degrees, and in this embodiment, 125 degrees, and then the composite metal ribbon is wrapped around the first sheath layer 3-1 by a wrapping machine to form a wrapping layer 3-2, so that the wrapping layer 3-2 is pre-bonded and fixed to the first sheath layer 3-1; 3. Heating through a high-temperature pipe to a temperature of 120 to 145 degrees, 140 degrees in this embodiment; 4. The polyolefin is extruded outside the wrapping layer 3-2 by a second extruder to form a second sheath layer 3-3. The extrusion pressure is higher than that of the first extruder, and the extrusion pressure is 40 MPa to 50 MPa, and the present embodiment is 44 MPa. The extrusion temperature is higher than that of the first extruder, and the extrusion temperature is 130 to 160 degrees, and the present embodiment is 150 degrees, so that the first sheath layer 3-1, the wrapping layer 3-2 and the second sheath layer 3-3 form a composite sheath layer 3. The composite sheath layer 3 has good strength and support, and the compression strength can reach 700 kgf.

[0026] Step 6: Weave the metal wire outside the inner sheath 3 to form an armor layer, with a weaving coverage rate of not less than 90%. In this embodiment, steel wire is weaved outside the inner sheath 3, with a weaving coverage rate of 90%; thereby further improving the support of the cable through the armor layer; Step seven: extruding polyolefin on the outside of the armor layer 4 to form an outer sheath 5.

[0027] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-strength flexible cable, characterized in that: The invention comprises a main line core (1), a filling layer (2), an inner sheath (3), an armor layer (4) and an outer sheath (5); there are three main line cores (1), and the three main line cores (1) have the same structure; the three main line cores (1) are provided with a conductor (1-1) and a conductor insulation layer (1-2) in sequence from the inside to the outside along their respective radial directions; the conductor (1-1) is formed by twisting a plurality of Category 5 tinned conductors in a positive and negative direction, and the strands have a small pitch diameter ratio, and the inner layer pitch diameter ratio is smaller than the outer layer pitch diameter ratio during re-twisting; the conductor insulation layer (1-2) is formed by wrapping the conductor (1-1) with XLPE extrusion to form an XLPE The insulation layer (2) includes three filling strips, and the three filling strips have the same structure and are all made of halogen-free rubber; the inner sides of the cross-sections of the three filling strips are in contact with the two adjacent main line cores (1), and the outer sides thereof form a full circle with the main line cores (1); the three main line cores (1) and the three filling strips (2) are twisted into a cable core; the inner sheath (3) is a composite inner sheath; the inner sheath (3) is extruded outside the cable core; the armor layer (4) is braided with metal wires outside the inner sheath (3), and the braiding coverage is not less than 90%; the outer sheath (5) is extruded with polyolefin outside the armor layer (4).

2. The high-strength flexible cable according to claim 1, characterized in that: The inner sheath (3) comprises a first sheath layer (3-1), a wrapping layer (3-2) and a second sheath layer (3-3); the first sheath layer (3-1) is made of thermoplastic polyolefin and is extruded on the outside of a cable core formed by twisting three main wire cores (1) and three filling strips (2); the wrapping layer (3-2) is made of composite metal ribbon and is wrapped on the outside of the first sheath layer (3-1), with a wrapping overlap rate of 2% to 5%; the second sheath layer (3-3) is made of thermoplastic polyolefin and is extruded on the outside of the wrapping layer (3-2).

3. A production process for a high-strength flexible cable, characterized in that: The following steps are involved: Step 1, using a plurality of Category 5 tinned conductors to twist forward and reversely to form a conductor (1-1) of a main line core (1), wherein the twisting pitch multiple is 10 to 14 times; using a strand with a small pitch diameter ratio, the strand pitch diameter ratio is 23 to 25, and during re-twisting, the inner layer pitch diameter ratio is smaller than the outer layer pitch diameter ratio, and the pitch diameter ratio during re-twisting is 10 to 15; Step 2: Extruding XLPE outside the conductor (1-1) to form a conductor insulation layer (1-2) to produce a main line core (1); Step 3: extrude a filling strip (2) using halogen-free rubber, wherein the inner side of the cross section of the filling strip (2) is in contact with two adjacent main line cores (1), and the outer side of the filling strip (2) forms a complete circle with the main line cores (1); Step 4, three main line cores (1) and three filling strips (2) are twisted into a cable core; Step 5, making the inner sheath (3), firstly connecting the first extruder, the wrapping machine, the high-temperature pipe and the second extruder in series in sequence; 1. Extruding thermoplastic polyolefin onto the cable core formed by twisting three main cores (1) and three filling strips (2) through a first extruder to form a first sheath layer (3-1); the extrusion pressure is 10 MPa to 30 MPa, and the extrusion temperature is 115 degrees to 145 degrees; 2. After extrusion, the first sheath layer (3-1) is maintained at 115 to 145 degrees, and then the composite metal ribbon is wrapped around the first sheath layer (3-1) by a wrapping machine to form a wrapping layer (3-2), so that the wrapping layer (3-2) and the first sheath layer (3-1) are pre-bonded and fixed; 3. Heat through high-temperature pipes to a temperature of 120 to 145 degrees; 4. Extruding polyolefin on the outer surface of the wrapping layer (3-2) by a second extruder to form a second sheath layer (3-3), the extrusion pressure is higher than that of the first extruder, the extrusion pressure is 40 MPa to 50 MPa, the extrusion temperature is higher than that of the first extruder, the extrusion temperature is 130 degrees to 160 degrees, so that the first sheath layer (3-1), the wrapping layer (3-2) and the second sheath layer (3-3) form a composite sheath layer (3); Step 6: Weaving the metal wires onto the outer surface of the inner sheath (3) to form an armor layer, with the weaving coverage being no less than 90%; Step seven: extruding polyolefin on the outside of the armor layer (4) to form an outer sheath (5).

Images