High-voltage flexible pulse power coaxial cable and manufacturing method thereof

Abstract

The invention provides a high-voltage flexible pulse power coaxial cable and a manufacturing method thereof. The high-voltage flexible pulse power coaxial cable sequentially comprises an inner conductor, an inner semi-conductive layer, an insulating layer, an outer semi-conductive layer, an outer conductor, a non-metal belt wrapping layer and an outer sheath layer from inside to outside. According to the high-voltage flexible pulse power coaxial cable, the thermoplastic dynamic vulcanized rubber insulating material with specific components is extruded by a common plastic extruding machine to form the insulating layer, so that the high-voltage flexible pulse power coaxial cable which is stable in inductance and capacitance, relatively good in flexibility and relatively low in weight can be obtained, and meanwhile, the process control difficulty and the production cost are greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of cables, and in particular to a high-voltage flexible pulse power coaxial cable and a manufacturing method thereof. Background Art

[0002] As an emerging special power technology, pulse power technology can achieve energy compression and power amplification through slow energy storage and instantaneous release, and is widely used in electromagnetic emission, strong magnetic pulse, nuclear fusion and other fields. Usually, the pulse power system adopts a modular design, consisting of a large number of pulse power units, with huge instantaneous power. The connecting cables between the load and the energy storage module must withstand high voltage environment and high bending. The instantaneous current carrying capacity of a single cable can reach tens of thousands of amperes or even hundreds of thousands of amperes.

[0003] CN105575517A discloses a high-voltage coaxial cable, comprising a fixing ring, a protective layer, a fluoroplastic fire-resistant layer and a semiconductor layer, wherein the fixing ring is arranged on the outside of the protective layer, the fixing ring is clamped and connected to the protective layer, mounting clamps are arranged on both sides of the fixing ring, the mounting clamps are welded to the fixing ring, mounting holes are arranged on the mounting clamps, the protective layer, the fluoroplastic fire-resistant layer and the semiconductor layer are glued and connected in sequence from the outside to the inside, an insulating layer, a shielding layer, a composite steel belt layer and a copper tube are arranged in the semiconductor layer, the insulating layer, the shielding layer, the composite steel belt layer and the copper tube are glued and connected in sequence from the outside to the inside, a filler is arranged in the copper tube, the high-voltage coaxial cable has a compact structure, good anti-deformation effect, is not easy to be damaged, is resistant to high temperature and is easy to install.

[0004] CN111223588A discloses a DC high-voltage ultra-flexible pulse high-current water-cooled coaxial cable, including a cable core and a sheath, wherein the cable core includes an inner conductor and an outer conductor, wherein the seven inner conductors in the center are twisted and then extruded into an inner sheath, and an outer conductor is wrapped around the inner sheath, and an outer sheath is extruded outside the outer conductor, wherein the inner and outer conductors include copper single wire strands and copper cooling tubes twisted together, and a twisted steel wire rope as a central bearing core, wherein the copper single wires in the copper single wire strands and the copper cooling tubes are coated with a semi-conductive material coating. This is a double-core cable, wherein the inner conductor and the outer conductor are coaxially distributed in a circular manner, and when working, currents of equal magnitude and opposite directions are passed through the same loop, which can eliminate the electromotive force between the inner and outer conductors and offset the magnetic field between the inner and outer conductors. The coaxial cable has no radiated magnetic field to the outside, and can be compactly arranged to improve the electromagnetic compatibility and integration of the equipment.

[0005] However, the above-mentioned high-voltage coaxial cable is a cable with a built-in cooling tube. This type of structure has obvious disadvantages: 1) The rubber hose has poor heat aging resistance and there are risks of aging, cracking, and medium leakage after long-term use; 2) The copper cooling tube is relatively hard, which affects the overall bending of the cable and cannot be installed in a small space. In addition, the cost of the copper tube is relatively high.

[0006] CN107154285A discloses a manufacturing method and cable for high power transmission equipment. The structure of the cable for high power transmission equipment from the inside to the outside is: inner conductor, first semi-conductive wrapped shielding layer, inner conductor insulation, second semi-conductive wrapped shielding layer, outer conductor, wrapped layer, outer conductor insulation and outer sheath. The inner conductor insulation layer is made of silicone rubber; the outer conductor is woven with one or more layers of tinned copper wire; the outer conductor insulation layer is made of silicone rubber; and the outer sheath layer is made of polyurethane. The cable for high power transmission equipment is a flexible coaxial cable, and the insulating material has the problem of high and unstable dielectric constant. Moreover, the insulating layer of the flexible coaxial cable is manufactured by a relatively complex steam vulcanization method, the production line investment cost is large, and the process control is complex.

[0007] Therefore, it is of great significance to provide a high-voltage flexible pulse power coaxial cable having a stable dielectric constant and a low hardness value and density value and a manufacturing method thereof. Summary of the invention

[0008] In view of the problems existing in the prior art, the present invention provides a high-voltage flexible pulse power coaxial cable and a manufacturing method thereof. By adopting a thermoplastic dynamically vulcanized rubber insulating material with a specific composition and extruding it through a common extruder to form an insulating layer, a high-voltage flexible pulse power coaxial cable with stable inductance and capacitance, good flexibility and low weight can be obtained, while the difficulty of process control and production cost are greatly reduced.

[0009] To achieve this object, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a high-voltage flexible pulse power coaxial cable, which comprises, from inside to outside, an inner conductor, an inner semi-conductive layer, an insulating layer, an outer semi-conductive layer, an outer conductor, a non-metallic tape wrapping layer and an outer sheath layer;

[0011] The insulating layer is formed by extruding a thermoplastic dynamically vulcanized rubber insulating material; in terms of mass fraction, the thermoplastic dynamically vulcanized rubber insulating material comprises 100 parts of EPDM, 50 to 80 parts of polypropylene, 50 to 70 parts of 80# white oil, 40 to 60 parts of kaolin, 1 to 2 parts of vulcanizing agent BIPB and 1 to 2 parts of antioxidant 1010.

[0012] The insulating layer of the high-voltage flexible pulse power coaxial cable described in the present invention is formed by extruding a thermoplastic dynamically vulcanized rubber insulating material. The dynamic vulcanization process is adopted to vulcanize the rubber during the melt blending of rubber and thermoplastic plastic. The rubber can be extruded using a common extruder, which effectively reduces the difficulty of process control and production costs.

[0013] In terms of mass fraction, the thermoplastic dynamic vulcanized rubber insulation material includes 100 parts of EPDM, 50 to 80 parts of polypropylene, 50 to 70 parts of 80# white oil, 40 to 60 parts of kaolin, 1 to 2 parts of vulcanizing agent BIPB and 1 to 2 parts of antioxidant 1010. By controlling the amount of the components of the EPDM and polypropylene blend, the dielectric constant of the thermoplastic dynamic vulcanized rubber material is stabilized in a specific range, and has a lower hardness value and density value. When the content of polypropylene is low, the dielectric constant of the material will increase in terms of electrical properties, and the density of the material will increase in terms of physical properties, which is not conducive to the inductance, capacitance and cost control of the finished cable; when the content of polypropylene is high, although it is conducive to improving the dielectric constant of the material and reducing the density of the material, it is not conducive to the hardness and tensile properties of the material, and has an impact on the softness of the finished cable.

[0014] The thermoplastic dynamically vulcanized rubber insulating material of the present invention comprises 100 parts of EPDM and 50 to 80 parts of polypropylene, for example, 50 parts, 55 parts, 60 parts, 70 parts, 73 parts, 75 parts or 80 parts, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0015] 50-70 parts of 80# white oil, for example, 50 parts, 55 parts, 60 parts, 65 parts, 67 parts or 70 parts, but not limited to the listed values, other values ​​not listed in the range are also applicable;

[0016] 40 to 60 parts of kaolin, for example, 40 parts, 43 parts, 45 parts, 50 parts, 55 parts, 58 parts or 60 parts, but it is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable;

[0017] 1 to 2 parts of vulcanizing agent BIPB, for example, can be 1 part, 1.2 parts, 1.5 parts, 1.7 parts, 1.9 parts or 2 parts, but are not limited to the listed values, and other values ​​not listed within the numerical range are also applicable; and 1 to 2 parts of antioxidant 1010, for example, can be 1 part, 1.2 parts, 1.5 parts, 1.7 parts, 1.9 parts or 2 parts, but are not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0018] Preferably, the nominal diameter of the inner conductor is 11-13 mm, for example, 11 mm, 11.2 mm, 11.5 mm, 11.7 mm, 12 mm, 12.5 mm or 13 mm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0019] Preferably, the inner semiconductive layer includes a first terylene tape wrapping with a nominal thickness of 0.1 to 0.3 mm, for example, it can be 0.1 mm, 0.15 mm, 0.18 mm, 0.2 mm, 0.25 mm, 0.28 mm or 0.3 mm, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are equally applicable; the wrapping overlap rate is 50% to 55%, for example, it can be 50%, 51%, 52%, 53%, 54%, 54.5% or 55%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are equally applicable.

[0020] Preferably, the nominal thickness of the insulating layer is 4 to 5 mm, for example, it can be 4 mm, 4.2 mm, 4.5 mm, 4.8 mm, 4.9 mm or 5 mm, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable; the nominal outer diameter of the insulating layer is 22 to 24 mm, for example, it can be 22 mm, 22.5 mm, 22.8 mm, 23 mm, 23.5 mm, 23.7 mm or 24 mm, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0021] Preferably, the dielectric constant of the insulating layer is 2.2-2.3, for example, 2.2, 2.21, 2.23, 2.25, 2.27, 2.29 or 2.3, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0022] Preferably, the outer semiconductive layer includes a second polyester tape wrapping with a nominal thickness of 0.1 to 0.3 mm, for example, it can be 0.1 mm, 0.12 mm, 0.15 mm, 0.18 mm, 0.2 mm, 0.25 mm or 0.3 mm, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable; the wrapping overlap rate is 50% to 55%, for example, it can be 50%, 51%, 52%, 53%, 54%, 54.5% or 55%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0023] The inner semi-conductive layer of the present invention includes a first terylene tape wrapping with a nominal thickness of 0.1 to 0.3 mm, and the outer semi-conductive layer includes a second terylene tape wrapping with a nominal thickness of 0.1 to 0.3 mm. Compared with traditional semi-conductive cloth tapes, the outer semi-conductive layer has the characteristics of smoother and tighter wrapping, can effectively homogenize the electric field, and ensure the electrical performance of the cable.

[0024] Preferably, the outer conductor is made by braiding multiple strands of bare copper wires.

[0025] Preferably, the non-metallic tape wrapping layer includes non-woven fabric, and the wrapping overlap rate is 10% to 35%, for example, it can be 10%, 11%, 12%, 15%, 20%, 25%, 30% or 35%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0026] Preferably, the outer sheath layer includes a nitrile-PVC composite material, and the nominal thickness of the outer sheath layer is 3 to 4 mm, for example, it can be 3 mm, 3.2 mm, 3.5 mm, 3.7 mm, 3.8 mm, 3.9 mm or 4 mm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0027] Preferably, the nominal outer diameter of the high-voltage flexible pulse power coaxial cable is 33.5mm to 34.5mm, for example, it can be 33.5mm, 33.6mm, 33.7mm, 33.8mm, 34mm, 34.2mm or 34.5mm, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0028] In a second aspect, the present invention further provides a method for manufacturing the high-voltage flexible pulse power coaxial cable as described in the first aspect, the manufacturing method comprising:

[0029] A plurality of bare copper monofilaments are bundle-twisted and re-twisted to form an inner conductor, and a first terylene tape is overlapped and wrapped around the outer side of the inner conductor, a thermoplastic dynamically vulcanized rubber insulating material is extruded, a second terylene tape is overlapped and wrapped, a double-layer bare copper wire is woven, a non-woven fabric is overlapped and wrapped, and a nitrile-PVC composite material is extruded, thereby obtaining the high-voltage flexible pulse power coaxial cable.

[0030] The inner conductor of the high-voltage flexible pulse power coaxial cable described in the present invention is made of multiple bare copper single wires after bundle twisting and re-twisting, and has high softness; then, overlapping terephthalate tapes are wrapped to form inner and outer semi-conductive layers. Compared with traditional semi-conductive cloth tapes, the inner conductor has the characteristics of smoother and tighter wrapping, can effectively homogenize the electric field, and ensure the electrical performance of the cable; and the outer conductor is woven with double layers of bare copper wires, which can meet the bending performance requirements of the cable; finally, nitrile-PVC composite material is extruded to form an outer sheath layer, and the nitrile-PVC composite material has excellent anti-cracking performance, mechanical and physical properties, and processing performance, further ensuring the reliability of the high-voltage flexible pulse power coaxial cable.

[0031] The bare copper monofilament of the present invention is a sixth type of stranded bare copper conductor that meets the requirements of GB / T3956, has high flexibility, and is convenient for construction and operation.

[0032] Preferably, the diameter of the bare copper monofilament is 0.180-0.200 mm, for example, it can be 0.180 mm, 0.183 mm, 0.185 mm, 0.19 mm, 0.195 mm, 0.198 mm or 0.200 mm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0033] Preferably, the bundling direction of the bundle twisting is opposite to the twisting direction of the multi-twist.

[0034] Preferably, the pitch diameter ratio of the inner conductor: strand 25-30, for example, may be 25, 26, 27, 28, 29 or 30, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0035] The inner layer 15-20 may be, for example, 15, 15.5, 16, 17, 18, 19, 19.5 or 20, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0036] The outer layers 12 to 16 may be, for example, 12, 12.5, 13, 14, 15, 15.5 or 16, but are not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0037] Preferably, the thermoplastic dynamically vulcanized rubber insulating material is dried before extrusion.

[0038] The thermoplastic dynamically vulcanized rubber insulating material of the present invention comprises a thermoplastic dynamically vulcanized rubber insulating material with the brand number of SV8275.

[0039] Preferably, the drying temperature is 100-110°C, for example, 100°C, 102°C, 104°C, 105°C, 108°C, 109°C or 110°C, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0040] The time is 1 to 3 hours, for example, it can be 1 hour, 1.2 hours, 1.5 hours, 2 hours, 2.5 hours, 2.7 hours or 3 hours, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0041] Preferably, the process parameters of the extruded thermoplastic dynamically vulcanized rubber insulation material include:

[0042] The temperature zones of the fuselage are: Zone 1 148-158°C, for example, it can be 148°C, 149°C, 150°C, 153°C, 155°C or 158°C, but it is not limited to the listed values, and other values ​​not listed in the range are also applicable;

[0043] Zone 2: 158-168°C, for example, 158°C, 160°C, 162°C, 165°C, 166°C or 168°C, but not limited to the listed values, other values ​​not listed within the range are also applicable;

[0044] Zone 3: 163-173°C, for example, 163°C, 165°C, 167°C, 169°C, 170°C or 173°C, but not limited to the listed values, other values ​​not listed within the range are also applicable;

[0045] Zone 4: 170-180°C, for example, 170°C, 172°C, 175°C, 177°C, 178°C or 180°C, but not limited to the listed values, other values ​​not listed within the range are also applicable;

[0046] Zone 5: 171-181°C, for example, 171°C, 172°C, 175°C, 177°C, 179°C or 181°C, but not limited to the listed values, other values ​​not listed within the range are also applicable;

[0047] Zone 6: 173-183°C, for example, 173°C, 175°C, 177°C, 180°C, 182°C or 183°C, but not limited to the listed values, other values ​​not listed in the range are also applicable;

[0048] The temperature zones of the head and neck are: 175-185°C for the flange zone, for example, 175°C, 177°C, 179°C, 180°C, 183°C or 185°C, etc., but are not limited to the listed values, and other values ​​not listed within the range are also applicable;

[0049] The first zone is 177-187°C, for example, it can be 177°C, 178°C, 180°C, 182°C, 185°C or 187°C, but it is not limited to the listed values, and other values ​​not listed in the range are also applicable;

[0050] The second zone of the mold is 179-189° C., for example, it can be 179° C., 180° C., 182° C., 185° C., 188° C. or 189° C., but is not limited to the listed values, and other values ​​not listed in the range are also applicable;

[0051] The temperature in the mode 3 zone is 179-189°C, for example, it can be 179°C, 180°C, 182°C, 185°C, 188°C or 189°C, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0052] In the present invention, the fuselage and the head are heated by thermocouples; the fuselage is cooled by air from a blower; and the wire core after extruding the thermoplastic dynamic vulcanized rubber insulation material is cooled by water at normal temperature.

[0053] Preferably, the braiding density of the double-layer bare copper wire is ≥85%, for example, it can be 85%, 86%, 88%, 89%, 90%, 93% or 95%, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0054] The weaving pitch is 185 to 200 mm, for example, it can be 185 mm, 188 mm, 189 mm, 190 mm, 195 mm, 197 mm or 200 mm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0055] Preferably, the diameter of the bare copper wire is 0.293-0.300 mm, for example, it can be 0.293 mm, 0.294 mm, 0.295 mm, 0.297 mm, 0.299 mm or 0.300 mm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0056] The present invention preferably has a weaving density of ≥85% for the double-layer bare copper wire and a weaving pitch of 185-200 mm, so that the inner and outer conductors have the same cross-sectional area and the same DC resistance, so as to achieve low resistance and high flexibility for the inner and outer conductors when forming a large current-carrying loop, thereby meeting the system's requirements for the bending performance of the cable.

[0057] Preferably, the extruded nitrile-PVC composite material is produced by an extruder in a tube extrusion manner.

[0058] The nitrile-PVC composite material of the present invention comprises a nitrile-PVC composite elastomer material with the brand number of ND(-20) / PVR-90.

[0059] Preferably, the process parameters of the extruded nitrile-PVC composite material include:

[0060] The temperature zones of the fuselage are: Zone 1 145-155°C, for example, it can be 145°C, 147°C, 149°C, 150°C, 153°C or 155°C, but it is not limited to the listed values, and other values ​​not listed in the range are also applicable;

[0061] Zone 2: 150-160°C, for example, 150°C, 152°C, 155°C, 157°C, 159°C or 160°C, but not limited to the listed values, other values ​​not listed within the range are also applicable;

[0062] Zone 3: 155-165°C, for example, 155°C, 157°C, 159°C, 160°C, 163°C or 165°C, but not limited to the listed values, other values ​​not listed in the range are also applicable;

[0063] Zone 4: 160-170°C, for example, 160°C, 162°C, 165°C, 168°C, 169°C or 170°C, but not limited to the listed values, other values ​​not listed within the range are also applicable;

[0064] Zone 5: 163-173°C, for example, 163°C, 165°C, 168°C, 170°C, 172°C or 173°C, but not limited to the listed values, other values ​​not listed within the range are also applicable;

[0065] Zone 6: 165-175°C, for example, 165°C, 166°C, 168°C, 170°C, 173°C or 175°C, but not limited to the listed values, other values ​​not listed within the range are also applicable;

[0066] The temperature zones of the head and neck are: 167-177°C for the flange zone, for example, 167°C, 168°C, 169°C, 170°C, 175°C or 177°C, etc., but are not limited to the listed values, and other values ​​not listed within the range are also applicable;

[0067] The first zone is 170-180°C, for example, it can be 170°C, 172°C, 175°C, 177°C, 179°C or 180°C, but it is not limited to the listed values, and other values ​​not listed in the range are also applicable;

[0068] The second zone of the mold is 170-180° C., for example, it can be 170° C., 172° C., 175° C., 177° C., 179° C. or 180° C., but is not limited to the listed values, and other values ​​not listed within the range are also applicable;

[0069] The temperature in the third mode zone is 170-180°C, for example, it can be 170°C, 172°C, 175°C, 177°C, 179°C or 180°C, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0070] In the present invention, the fuselage and the head are heated by thermocouples; the fuselage is cooled by air from a blower; and the outer sheath layer is cooled by water at normal temperature.

[0071] As a preferred technical solution of the present invention, the manufacturing method comprises:

[0072] (1) A plurality of bare copper monofilaments with a diameter of 0.180 to 0.200 mm are bundled and twisted to form an inner conductor; the bundling direction of the bundled twisting is opposite to the twisting direction of the twisted twisting; the pitch diameter ratio of the inner conductor is: 25 to 30 for the strands, 15 to 20 for the inner layer, and 12 to 16 for the outer layer;

[0073] (2) wrapping a first terylene tape around the inner conductor to form an inner semi-conductive layer;

[0074] (3) The thermoplastic dynamically vulcanized rubber insulation material is dried at a temperature of 100 to 110° C. for 1 to 3 hours and then extruded to form an insulation layer; the process parameters include:

[0075] The temperature zones of the fuselage are: Zone 1 148-158°C, Zone 2 158-168°C, Zone 3 163-173°C, Zone 4 170-180°C, Zone 5 171-181°C, Zone 6 173-183°C;

[0076] The temperature zones of the die head and die neck are: flange zone 175-185°C, die zone 1 177-187°C, die zone 2 179-189°C, die zone 3 179-189°C;

[0077] (4) overlapping and wrapping a second terylene tape to form an outer semi-conductive layer;

[0078] (5) braiding a double layer of bare copper wire with a braiding density of ≥85% and a braiding pitch of 185 to 200 mm to form an outer conductor; the diameter of the bare copper wire is 0.293 to 0.300 mm;

[0079] (6) Overlapping the non-woven fabric to form a non-metallic tape wrapping layer;

[0080] (7) The extruder adopts a tube extrusion method to produce and extrude the nitrile-PVC composite material to form an outer sheath layer to obtain the high-voltage flexible pulse power coaxial cable;

[0081] The process parameters of the extruded nitrile-PVC composite material include:

[0082] The temperature zones of the fuselage are: Zone 1 145-155°C, Zone 2 150-160°C, Zone 3 155-165°C, Zone 4 160-170°C, Zone 5 163-173°C, Zone 6 165-175°C;

[0083] The temperature zones of the machine head and machine neck are: flange zone 167~177℃, mold zone 1 170~180℃, mold zone 2 170~180℃, mold zone 3 170~180℃.

[0084] Compared with the prior art, the present invention has at least the following beneficial effects:

[0085] The insulating layer of the high-voltage flexible pulse power coaxial cable provided by the present invention is formed by extruding a thermoplastic dynamically vulcanized rubber insulating material, and the dielectric constant is stable between 2.2 and 2.3, which solves the problem that the dielectric constant of traditional materials is too large or the hardness value is too high, so that the cable has both stable electrical properties such as inductance and capacitance and good softness. At the same time, it can be extruded with an ordinary extruder, which solves the complex process of vulcanization or cross-linking of traditional materials with high-temperature and high-pressure gas, making processing and production more convenient, reducing the cost of manufacturing cables, and suitable for large-scale promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0086] Figure 1 It is a schematic diagram of the structure of a high-voltage flexible pulse power coaxial cable in a specific implementation manner of the present invention.

[0087] In the figure: 1-inner conductor; 2-inner semi-conductive layer; 3-insulating layer; 4-outer semi-conductive layer; 5-outer conductor; 6-non-metallic tape wrapping layer; 7-outer sheath layer. DETAILED DESCRIPTION

[0088] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0089] The present invention is further described in detail below. However, the following examples are only simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0090] As a specific embodiment of the present invention, a high voltage flexible pulse power coaxial cable is provided, and its structural schematic diagram is as follows: Figure 1 shown.

[0091] The high-voltage flexible pulse power coaxial cable comprises, from inside to outside, an inner conductor 1, an inner semi-conductive layer 2, an insulating layer 3, an outer semi-conductive layer 4, an outer conductor 5, a non-metallic tape wrapping layer 6 and an outer sheath layer 7;

[0092] The insulating layer 3 is formed by extruding a thermoplastic dynamically vulcanized rubber insulating material.

[0093] The thermoplastic dynamically vulcanized rubber insulating material in this specific embodiment is a thermoplastic dynamically vulcanized rubber insulating material with a brand number of SV8275, and the constituent raw materials are shown in Table 1.

[0094] Table 1

[0095] name factory Brand Weight EPDM Dow Chemical 4770 100 Polypropylene Yangzi Petrochemical F401 70 80# white oil China National Petroleum Corporation / 60 Kaolin Shanghai Yuanjiang Chemical / 50 Curing agent BIPB Akma F40P 1 Antioxidant 1010 BASF / 2

[0096] In Table 1, “ / ” means no content.

[0097] The main performance data of the thermoplastic dynamically vulcanized rubber insulation material in this specific embodiment are shown in Table 2.

[0098] Table 2

[0099]

[0100]

[0101] In Table 2, “ / ” means no content.

[0102] The nominal diameter of the inner conductor 1 is 12.7 mm;

[0103] The inner semiconductive layer 2 comprises a first terylene tape wrapping with a nominal thickness of 0.2 mm and a wrapping overlap rate of 53%;

[0104] The nominal thickness of the insulating layer 3 is 4.5 mm, the nominal outer diameter of the insulating layer is 23 mm, and the dielectric constant of the insulating layer 3 is 2.3.

[0105] The outer semiconductive layer 4 comprises a second polyester tape with a nominal thickness of 0.2 mm and a wrapping rate of 55%;

[0106] The outer conductor 5 is made of a plurality of bare copper wires braided together;

[0107] The non-metallic tape wrapping layer 6 is a layer of 0.2×50mm white non-woven fabric, and the wrapping overlap rate is 20%;

[0108] The outer sheath layer 7 comprises a nitrile-PVC composite material, and the nominal thickness of the outer sheath layer is 3.4 mm;

[0109] The nominal outer diameter of the high-voltage flexible pulse power coaxial cable is 34.5 mm.

[0110] As a specific embodiment of the present invention, a method for manufacturing the above-mentioned high-voltage flexible pulse power coaxial cable is also provided, and the manufacturing method comprises the following steps:

[0111] (1) 10 bare copper monofilaments with a diameter of 0.200 mm are bundled and twisted to form an inner conductor 1; the bundling direction of the bundle twisting is opposite to the twisting direction of the twisting; the pitch diameter ratio of the inner conductor 1 is: strand 27, inner layer 16, outer layer 14;

[0112] (2) wrapping a first terylene tape around the inner conductor 1 to form an inner semiconductive layer 2;

[0113] (3) The thermoplastic dynamically vulcanized rubber insulation material is dried at a temperature of 105° C. for 2 hours and then extruded to form an insulation layer 3; the process parameters include:

[0114] The temperature zones of the fuselage are: Zone 1 153°C, Zone 2 163°C, Zone 3 168°C, Zone 4 175°C, Zone 5 176°C, Zone 6 178°C;

[0115] The temperature zones of the die head and die neck are: flange zone 180℃, die zone 182℃, die zone 2 184℃, die zone 3 184℃;

[0116] (4) overlapping and wrapping a second terylene tape to form an outer semiconductive layer 4;

[0117] (5) braiding a double layer of bare copper wire at a braiding density of 88% and a braiding pitch of 190 mm to form an outer conductor 5; the diameter of the bare copper wire is 0.300 mm;

[0118] (6) overlapping and wrapping the non-woven fabric to form a non-metallic tape wrapping layer 6;

[0119] (7) The extruder adopts a tube extrusion method to produce and extrude the nitrile-PVC composite material to form an outer sheath layer 7, thereby obtaining the high-voltage flexible pulse power coaxial cable;

[0120] The process parameters of the extruded nitrile-PVC composite material include:

[0121] The temperature zones of the fuselage are: Zone 1 150℃, Zone 2 155℃, Zone 3 160℃, Zone 4 165℃, Zone 5 168℃, Zone 6 170℃;

[0122] The temperature zones of the machine head and neck are: flange zone 172℃, mold zone 1 175℃, mold zone 2 175℃, and mold zone 3 175℃.

[0123] The test results of the high-voltage flexible pulse power coaxial cable manufactured by this specific embodiment are as follows:

[0124] 1) Long-term maximum operating temperature of conductor: 90℃;

[0125] 2) Cable bending radius: ≤300mm. (Radius 300mm, cylindrical roller winding test, the sample should be free of cracks, fissures and other damage after the test, and the sample should not be broken down after the voltage withstand test);

[0126] 3) 20℃ DC resistance: inner conductor resistance + outer conductor resistance ≤ 0.6Ω / km (±5%);

[0127] 4) Inductance: 170 (±5%) μH / km (@1kHz);

[0128] 5) Capacitance: 240 (±5%) nF / km (@1kHz).

[0129] To sum up, the high-voltage flexible pulse power coaxial cable provided by the present invention adopts a special insulating layer to solve the problem of large dielectric constant or high hardness value of traditional materials, so that the cable has both stable electrical properties such as inductance and capacitance and good softness; the manufacturing method of the high-voltage flexible pulse power coaxial cable adopts a dynamic vulcanization process, and the extruder extrude the insulating material, which is simple to control, convenient to process and produce, and low in cable manufacturing cost, which is suitable for large-scale promotion and application.

[0130] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A high voltage flexible pulse power coaxial cable, characterized in that: The high-voltage flexible pulse power coaxial cable comprises, from inside to outside, an inner conductor, an inner semi-conductive layer, an insulating layer, an outer semi-conductive layer, an outer conductor, a non-metallic tape wrapping layer and an outer sheath layer; The insulating layer is formed by extruding a thermoplastic dynamically vulcanized rubber insulating material; in terms of mass fraction, the thermoplastic dynamically vulcanized rubber insulating material comprises 100 parts of EPDM, 50 to 80 parts of polypropylene, 50 to 70 parts of 80# white oil, 40 to 60 parts of kaolin, 1 to 2 parts of vulcanizing agent BIPB and 1 to 2 parts of antioxidant 1010.

2. The high voltage flexible pulse power coaxial cable according to claim 1, characterized in that: The nominal diameter of the inner conductor is 11 to 13 mm; Preferably, the inner semi-conductive layer comprises a first terylene tape wrapping with a nominal thickness of 0.1 to 0.3 mm and a wrapping overlap rate of 50% to 55%; Preferably, the nominal thickness of the insulating layer is 4 to 5 mm, and the nominal outer diameter of the insulating layer is 22 to 24 mm; Preferably, the dielectric constant of the insulating layer is 2.2-2.

3.

3. The high voltage flexible pulse power coaxial cable according to claim 1 or 2, characterized in that: The outer semi-conductive layer comprises a second polyester tape with a nominal thickness of 0.1 to 0.3 mm and a wrapping rate of 50% to 55%; Preferably, the outer conductor is braided from multiple strands of bare copper wires; Preferably, the non-metallic tape wrapping layer comprises non-woven fabric, and the wrapping overlap rate is 10% to 35%; Preferably, the outer sheath layer comprises a nitrile-PVC composite material, and the nominal thickness of the outer sheath layer is 3 to 4 mm; Preferably, the nominal outer diameter of the high-voltage flexible pulse power coaxial cable is 33.5 mm to 34.5 mm.

4. A method for manufacturing a high voltage flexible pulse power coaxial cable as claimed in any one of claims 1 to 3, characterized in that: The manufacturing method comprises: A plurality of bare copper monofilaments are bundle-twisted and re-twisted to form an inner conductor, and a first terylene tape is overlapped and wrapped around the outer side of the inner conductor, a thermoplastic dynamically vulcanized rubber insulating material is extruded, a second terylene tape is overlapped and wrapped, a double-layer bare copper wire is woven, a non-woven fabric is overlapped and wrapped, and a nitrile-PVC composite material is extruded, thereby obtaining the high-voltage flexible pulse power coaxial cable.

5. The manufacturing method according to claim 4, characterized in that: The diameter of the bare copper monofilament is 0.180-0.200 mm; Preferably, the bundling direction of the bundle twisting is opposite to the twisting direction of the re-twisting; Preferably, the pitch-to-diameter ratio of the inner conductor is: 25-30 for the strand, 15-20 for the inner layer, and 12-16 for the outer layer.

6. The manufacturing method according to claim 4 or 5, characterized in that: The thermoplastic dynamically vulcanized rubber insulation material is dried before extrusion; Preferably, the drying temperature is 100-110°C and the time is 1-3h; Preferably, an extruder is used to extrude the thermoplastic dynamically vulcanized rubber insulation material; Preferably, the process parameters of the extruded thermoplastic dynamically vulcanized rubber insulation material include: The temperature zones of the fuselage are: Zone 1 148-158°C, Zone 2 158-168°C, Zone 3 163-173°C, Zone 4 170-180°C, Zone 5 171-181°C, Zone 6 173-183°C; The temperature zones of the machine head and neck are: flange zone 175~185℃, mold zone 1 177~187℃, mold zone 2 179~189℃, mold zone 3 179~189℃.

7. The manufacturing method according to any one of claims 4 to 6, characterized in that: The braiding density of the double-layer bare copper wire is ≥85%, and the braiding pitch is 185-200 mm; Preferably, the diameter of the bare copper wire is 0.293-0.300 mm.

8. The manufacturing method according to any one of claims 4 to 7, characterized in that: The extruded nitrile-PVC composite material is produced by an extruder in a tube extrusion method.

9. The manufacturing method according to any one of claims 4 to 8, characterized in that: The process parameters of the extruded nitrile-PVC composite material include: The temperature zones of the fuselage are: Zone 1 145-155°C, Zone 2 150-160°C, Zone 3 155-165°C, Zone 4 160-170°C, Zone 5 163-173°C, Zone 6 165-175°C; The temperature zones of the machine head and machine neck are: flange zone 167~177℃, mold zone 1 170~180℃, mold zone 2 170~180℃, mold zone 3 170~180℃.

10. The manufacturing method according to any one of claims 4 to 9, characterized in that: The manufacturing method comprises: (1) A plurality of bare copper monofilaments with a diameter of 0.180 to 0.200 mm are bundled and twisted to form an inner conductor; the bundling direction of the bundled twisting is opposite to the twisting direction of the twisted twisting; the pitch diameter ratio of the inner conductor is: 25 to 30 for the strands, 15 to 20 for the inner layer, and 12 to 16 for the outer layer; (2) wrapping a first terylene tape around the inner conductor to form an inner semi-conductive layer; (3) The thermoplastic dynamically vulcanized rubber insulation material is dried at a temperature of 100 to 110° C. for 1 to 3 hours and then extruded to form an insulation layer; the process parameters include: The temperature zones of the fuselage are: Zone 1 148-158°C, Zone 2 158-168°C, Zone 3 163-173°C, Zone 4 170-180°C, Zone 5 171-181°C, Zone 6 173-183°C; The temperature zones of the die head and die neck are: flange zone 175-185°C, die zone 1 177-187°C, die zone 2 179-189°C, die zone 3 179-189°C; (4) overlapping and wrapping a second terylene tape to form an outer semi-conductive layer; (5) braiding a double layer of bare copper wire with a braiding density of ≥85% and a braiding pitch of 185 to 200 mm to form an outer conductor; the diameter of the bare copper wire is 0.293 to 0.300 mm; (6) Overlapping the non-woven fabric to form a non-metallic tape wrapping layer; (7) The extruder adopts a tube extrusion method to produce and extrude the nitrile-PVC composite material to form an outer sheath layer to obtain the high-voltage flexible pulse power coaxial cable; The process parameters of the extruded nitrile-PVC composite material include: The temperature zones of the fuselage are: Zone 1 145-155°C, Zone 2 150-160°C, Zone 3 155-165°C, Zone 4 160-170°C, Zone 5 163-173°C, Zone 6 165-175°C; The temperature zones of the machine head and machine neck are: flange zone 167~177℃, mold zone 1 170~180℃, mold zone 2 170~180℃, mold zone 3 170~180℃.

Images