A method for producing concentrically twisted special-shaped cable conductor

Abstract

The invention belongs to the technical field of cable production, and provides a method for producing a concentric twisted special-shaped cable conductor. The method is completed based on a concentric twisting device, and comprises the following steps: selecting a copper rod whose mechanical properties, conductive properties, surface quality and diameter meet the standards of the cable conductor to be produced; adjusting the actual equivalent circle diameter of a finished wire drawing die according to the equivalent circle diameter of a concentric twisted wire monofilament in the cable conductor to be produced, adjusting an annealing coefficient and a wire-receiving tension according to a test result of the wire monofilament, and completing the drawing of the wire monofilament; when and only when the equivalent circle diameter, resistivity and elongation of the obtained wire monofilament meet preset standards, entering a rewinding process; rewinding a plurality of obtained wire monofilaments on a wire storage wheel at the same time; adjusting the wire-releasing tension, and twisting the rewound wire monofilaments, and pre-twisting is required during the twisting process, and the cable conductor is evenly produced after pre-twisting to complete the production of the concentric twisted special-shaped cable conductor.

Description

Technical Field

[0001] The invention belongs to the technical field of cable production, and in particular relates to a method for producing a concentrically twisted special-shaped cable conductor. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] At present, the equipment used to produce cable conductors includes tube stranding machines, cage stranding machines, fork stranding machines, bow stranding machines, frame stranding machines and concentric stranding machines. Different stranding equipment can meet the needs of products with different technical requirements according to their technical characteristics. However, for long-length, high-stability power cable conductors, the most commonly used production equipment is the frame stranding machine. The frame stranding machine can carry a large number of single wires and a large number of single wires. The quality of the products produced is stable and the production speed is high (usually up to 20 to 40 meters / minute). It is widely used in the cable industry. With the continuous upgrading and iteration of the frame stranding machine and the exploration of technology, it is currently possible to stably realize the production of various types of conductors such as non-compacted, compacted, and shaped wire.

[0004] The frame stranding machine adopts a single-wire rotating concentric stranding method. When the number of single wires it carries is large and the length is large, the rotational inertia caused by the stranding is large, and the requirements for the mechanical structure, load-bearing, ground foundation, safety and other aspects of the equipment itself are very high, and the production speed is difficult to further increase. The production principle of the concentric stranding equipment is the same as that of the frame stranding machine. It adopts a single-wire non-rotating design, and the rotational inertia during the stranding process can be greatly reduced. While ensuring product quality, it can significantly increase the production speed (the production speed can reach more than 80 meters / minute). Concentric stranding has been realized for the practical application of non-compacted and compacted steel-core aluminum stranded wires and even split conductors for high-voltage cables, but concentric stranding equipment is used for the production of compacted or non-compacted stranded copper conductors, and has not been widely used in cable production. Summary of the invention

[0005] In order to solve the above problems, the present invention proposes a method for producing concentrically twisted special-shaped cable conductors, which adopts concentric twisting equipment to realize the production of cable conductors, and adds a rewinding process between the single-filament performance inspection process and the twisting process in the traditional production process, and adopts a double-disk mode to carry out rewinding and twisting of the single wire. At the same time, the equivalent circular diameter of the single wire of the drawn profile wire in the wire drawing process is adjusted in consideration of the rewinding speed and the production speed, thereby improving the production efficiency of the cable conductor as a whole.

[0006] According to some embodiments, the solution of the present invention provides a method for producing a concentrically twisted special-shaped cable conductor, which adopts the following technical solution:

[0007] A method for producing a coaxially twisted special-shaped cable conductor is based on a coaxially twisted device to complete the production, comprising the following steps:

[0008] Select copper rods with mechanical properties, electrical conductivity, surface quality and diameter that meet the standards for the cable conductors to be produced;

[0009] According to the equivalent circle diameter of the concentrically twisted wire monofilament in the cable conductor to be produced, the actual equivalent circle diameter of the finished wire drawing die is adjusted, and according to the inspection results of the wire monofilament, the annealing coefficient and the wire-winding tension are adjusted to complete the drawing of the wire monofilament;

[0010] If and only if the equivalent circle diameter, resistivity and elongation of the obtained shaped wire monofilament all meet the preset standards, the rewinding process is entered;

[0011] Rewinding the obtained plurality of shaped wire monofilaments onto the wire storage wheel at the same time;

[0012] Adjust the pay-off tension and twist the rewound wire monofilaments. Pre-twisting is required during the twisting process. After pre-twisting, the production speed is evenly increased to form the cable conductor, thus completing the production of concentric twisted special-shaped cable conductors.

[0013] As a further technical limitation, a vertical frame is adopted for wire taking-up, and the capacity of the vertical frame is twice the capacity of the wire taking-up reel, which reduces the number of reel changes and reduces labor intensity.

[0014] As a further technical limitation, during the process of drawing the molded wire monofilament, the annealing coefficient is adjusted so that the elongation of the molded wire monofilament is greater than 30%.

[0015] As a further technical limitation, before twisting the rewound shaped wire monofilaments, the pay-out tension of the shaped wire monofilaments to be twisted is tested and adjusted to control the tension within a preset range and maintain uniform pay-out tension; after the pay-out tension adjustment is completed, twisting of the shaped wire monofilaments is started.

[0016] Furthermore, after the pay-off tension is adjusted, the coaxial twisting device is started at a speed of 1 m / min to pre-twist the monofilaments of each layer of the profile wire, and the speed of the coaxial twisting device is evenly increased after the pre-twisting is completed.

[0017] Furthermore, after the pay-off tension is adjusted, the same production speed is maintained to reduce the resistance margin variation at the beginning and end of the conductor.

[0018] As a further technical limitation, the preset standard is GB / T3953 standard; the equivalent circular diameter of the drawn wire monofilament is greater than the equivalent circular diameter of the process standard, that is, the equivalent circular diameter of the concentric stranded wire monofilament = the standard process equivalent circular diameter + Xmm, wherein 0 <X<0.04。

[0019] As a further technical limitation, the concentric twisting equipment includes a single-reel mode and a double-reel mode; when the double-reel mode is adopted, the single wires of the cable conductor are twisted while being rewound during the production process of the cable conductor.

[0020] As a further technical limitation, in the process of drawing the profiled wire monofilament, the concentration of the drawing liquid is controlled at 15% to 17%, and the pH value is controlled at 7 to 8.

[0021] As a further technical limitation, an electronic balance and a ruler are used to weigh and measure the equivalent circular diameter of the drawn wire single wire, and a resistance tester and a tensile machine are used to test the resistivity and elongation of the drawn wire single wire.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention adopts coaxial twisting equipment to realize the production of cable conductors, adds a rewinding process between the single-filament performance inspection process and the twisting process in the traditional production process, adopts a double-disk mode to rewind and twist the single-filament simultaneously, and at the same time, considers the rewinding speed and the production speed to adjust the equivalent circular diameter of the single-filament drawn wire in the wire drawing process, thereby improving the production efficiency of the cable conductor as a whole. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings in the specification that constitute a part of this embodiment are used to provide a further understanding of this embodiment. The schematic embodiments of this embodiment and their descriptions are used to explain this embodiment and do not constitute improper limitations on this embodiment.

[0025] Figure 1 The present invention is a flowchart of a method for producing a concentrically twisted special-shaped cable conductor in an embodiment of the present invention. DETAILED DESCRIPTION

[0026] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0027] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0028] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0029] In the present invention, terms such as "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "side", "bottom", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are relational words determined only for the convenience of describing the structural relationships of the various parts or elements of the present invention, and do not specifically refer to any part or element in the present invention and should not be understood as limitations on the present invention.

[0030] In the present invention, terms such as "fixed connection", "connected", "connection", etc. should be understood in a broad sense, indicating that it can be fixedly connected, integrally connected or detachably connected; it can be directly connected or indirectly connected through an intermediate medium. For relevant scientific research or technical personnel in this field, the specific meanings of the above terms in the present invention can be determined according to specific circumstances, and they cannot be understood as limitations on the present invention.

[0031] In the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0032] Example

[0033] The embodiment of the present invention introduces a method for producing a concentrically twisted special-shaped cable conductor.

[0034] like Figure 1 A method for producing a concentrically twisted special-shaped cable conductor is shown, comprising the following steps:

[0035] Step S01: rod selection process;

[0036] Step S02: wire drawing process;

[0037] Step S03: single-filament performance testing process;

[0038] Step S04: rewinding process;

[0039] Step S05: twisting process.

[0040] This embodiment uses a frame copper drawing machine to draw 8.0mm copper rods into required equivalent circular diameter profile wire monofilaments. The wire collection method is changed from disc-type wire collection to vertical frame-type wire collection, and the weight of the reel increases by 1.2 tons from 400-500kg; taking the equivalent diameter 3.20mm profile wire monofilament as an example, the reel length increases from 7.0km to 16.8km, and the reel length increases by about 2.4 times. The increase in the reel length can effectively reduce the number of reel changes during the production process, reduce the frequency of tooling transportation and joints, and can reduce the labor intensity by about 1 / 2.

[0041] In this embodiment, a concentric stranding device is used for stranding the shaped wire conductor, rather than a bunch strander. Since the wire reel is relatively far from the rotation center during the stranding process of the bunch strander, during the rotation of the stranding body, the wire reel will bear a very large centrifugal force. If the wire reel is not firmly locked, the wire reel will be thrown out of the stranding body, causing a personal safety accident. Therefore, to ensure mechanical safety and personal safety, the rotation speed of the stranding body of the bunch strander is not set too fast, which results in difficulty in further increasing the production speed, with the maximum being only about 40 meters per minute. While for the concentric stranding device, the pay-off reel is almost coincident with the rotation center of the stranding body, meaning that the centrifugal force it receives during the rotation of the stranding body is limited, and the stranding body can rotate at a relatively high speed. Correspondingly, the production speed is also greatly increased, reaching more than 80 meters per minute, which is more than twice the production speed of the bunch strander.

[0042] Compared with the bunch strander, the production process in this embodiment has changed. The production process of the shaped wire conductor by the bunch strander is: wire drawing → inspection → stranding. Due to the structural characteristics of the concentric stranding device, its production process of the shaped wire conductor has changed to: wire drawing → inspection → rewinding → stranding. The rewinding process is mainly carried out on the pay-off device at the far end of the equipment. Its main function is to rewind the shaped wire single wires in the vertical frame into the pay-off reel, so as to achieve the stranding of the shaped wire conductor. Note that the addition of the rewinding process does not affect the production efficiency. On the one hand, the rewinding speed is extremely fast, reaching 200 meters per minute. During rewinding, multiple shaped wire single wires are rewound simultaneously, that is, the rewinding time for multiple wires is the same as that for a single wire. On the other hand, the concentric stranding device has a single / double reel mode. In the double reel mode, the equipment can rewind and strand simultaneously.

[0043] It is precisely because of the addition of the rewinding process that the production process of the concentric stranding shaped wire conductor must be optimized from the wire drawing process. The relatively fast rewinding and production speeds of the concentric stranding mean that the shaped wire single wires will inevitably be drawn thinner, which also means that the equivalent circular diameter of the drawn shaped wire single wire should be larger than the equivalent circular diameter of the process standard, that is, the equivalent circular diameter of the concentric stranding shaped wire single wire = the standard process equivalent circular diameter + X mm, where 0 < X < 0.04. Only in this way can it be ensured that the resistance of the stranded shaped wire conductor meets the national standard requirements and can be used normally in the subsequent processes. This specific degree of thinning is not only related to the rewinding speed and production speed, but also has a great relationship with the annealing, elongation rate, and pay-off tension of the shaped wire single wire. On the premise that the rewinding speed and production speed are the same, when the annealing, elongation rate, and pay-off tension of the shaped wire single wire are larger, the degree of thinning of the shaped wire single wire will be larger, and a single wire with a larger equivalent circular diameter needs to be drawn. On the contrary, it is smaller, and only a single wire with a smaller equivalent circular diameter needs to be drawn.

[0044] Compared with the frame stranding machine, the coaxial stranding equipment used in this embodiment has better sealing. Each strand of the frame stranding machine only has a protective cover, and the entire strand is basically in a semi-open state. Noise will be emitted during the rotation of the strand, and copper powder attached to the monofilament will also be thrown out, which will have a certain impact on the health of production personnel and the production site environment. However, each swivel of the coaxial stranding equipment is located in a protective box, and the overall sealing and sound insulation are good. The noise generated by the rotation of the swivel cannot be transmitted from the inside, and there is almost no sound during the entire production process. Because the protective box isolates the swivel from the external environment, the copper powder on the surface of the monofilament of the profile wire only exists in the box and cannot contact the production personnel outside the box, and naturally cannot affect their health.

[0045] This embodiment takes the 240-section wire conductor as an example, because the 240-section wire conductor is composed of a three-layer structure of 50T-120T-240T, with more layers and a large enough cross-section. In addition, the inner layer of the 240-section wire conductor is a 50-section wire conductor, and the 50-section wire conductor is the inner layer cross-section of the 300- and 400-section wire conductors, so the 240-section wire conductor is generally representative.

[0046] As one or more embodiments, in step S01, a copper rod in T1M20 state is selected, which has mechanical properties, electrical conductivity, surface quality and diameter that meet the requirements of national standard GB / T-3952.

[0047] As one or more implementation modes, in step S02, a frame copper drawing machine is used to draw 50T, 120T and 240T shaped wire monofilaments respectively. If conditions permit, a double-head frame copper drawing machine can be used for production to improve production efficiency. In the wire drawing process, in order to ensure the quality and efficiency of the drawn monofilaments, the concentration of the drawing liquid is controlled at 15-17%, and the pH value is controlled at 7-8. Note that the finished die size parameter of the wire drawing machine operation interface is set to the actual equivalent circular diameter of the shaped wire drawing finished die, and cannot be set to the equivalent circular diameter of the drawn shaped wire monofilament, otherwise the equivalent circular diameter of the drawn shaped wire monofilament cannot reach the required size. If necessary, the finished die size parameter can be set to be larger than the actual equivalent circular diameter of the shaped wire drawing finished die to ensure that the equivalent circular diameter of the drawn shaped wire monofilament meets the requirements; other wire drawing process parameters are shown in Table 1.

[0048] Table 1 Wire drawing process parameters

[0049] Equivalent diameter of each specification of monofilament (mm) Finished mold size equivalent circle diameter mm Production speed m / s Annealing coefficient Take-up tension bar 50T / 2.97 3.04 8.0 8.6 0.3 120T / 2.81 2.88 8.0 8.6 1.0 240T / 3.16 3.23 8.0 8.6 0.5

[0050] As one or more implementation modes, in step S03, the shaped wire monofilament is drawn according to the drawing parameters in Table 1, and the equivalent circular diameter, resistivity and elongation of the produced shaped wire monofilament are shown in Table 2.

[0051] Table 2 Equivalent circular diameter, resistivity and elongation of monofilament of type wire

[0052]

[0053]

[0054] As one or more implementation modes, in step S04, the frame monofilament is rewound onto the wire storage wheel, and the rewinding speed of the over-end pay-off device is set at 100%, i.e., 200 m / min, to ensure the rewinding efficiency. The change in the equivalent circular diameter of the monofilament before and after rewinding is shown in Table 3.

[0055] Table 3 Comparison data of the monofilament before and after rewinding

[0056]

[0057]

[0058] After rewinding, the monofilament of the molded wire becomes thinner, with an average thinning degree of 0.009mm.

[0059] As one or more implementation modes, in step S05, before the conductor stranding is officially started, a tensile force meter is used to test the pay-off tension one by one, and the tension is controlled at 19-20kg to keep the pay-off tension uniform. Since the number of storage bottom wires will also affect the pay-off tension, when adjusting the pay-off tension, it is necessary to pay attention to consuming the bottom wire of each storage wheel or ensuring that the remaining bottom wire length is similar to avoid repeated adjustment of the pay-off tension in subsequent production. After the tension adjustment is completed, take the lead and slowly start the machine at a production speed of 1 meter / minute. During the startup process, pre-twist each layer of the wire monofilament to avoid affecting the conductor resistance and appearance roundness due to the problem of monofilament turning over. After the pre-twisting is completed, the speed is evenly increased to 80 meters / minute.

[0060] Comparative Example 1

[0061] The concentration and pH value of the drawing liquid were set to 7-8, the annealing coefficient was adjusted to 8.2, and the wire-taking tension was adjusted from 0.3 bar, 1.0 bar and 0.5 bar to 1.0 bar, 1.5 bar and 1.0 bar respectively.

[0062] According to the adjusted drawing parameters, the profiled wire monofilament is drawn, and its equivalent circle diameter, resistivity and elongation are shown in Table 4.

[0063] Table 4 Parameters of single wire after drawing

[0064]

[0065]

[0066]

[0067] Under the premise that the raw materials and finished product mold dimensions remain unchanged, the annealing coefficient is reduced and the winding tension is increased, resulting in an increase in the single-filament resistivity and a decrease in the elongation, but the overall performance still meets the requirements of the national standard GB / T3953.

[0068] The rewinding was carried out at a speed of 200 m / min. The changes in the equivalent diameter of the monofilament before and after rewinding are shown in Table 5.

[0069] Table 5 Data of single wire before and after rewinding

[0070]

[0071]

[0072] Under the same rewinding speed, due to the reduction of monofilament elongation, the thinning degree of monofilament after rewinding is somewhat reduced, about 0.007mm.

[0073] The tension of the stranding pay-off remains unchanged at 19-20kg, and the same operations are used for leading, pre-twisting and starting the machine, and the final speed is maintained at 80m / min.

[0074] Comparative Example 2

[0075] The foregoing process is consistent with Comparative Example 1, and the pay-off tension in the twisting step is adjusted from 19-20 kg to 16-18 kg.

[0076] Comparative Example 3

[0077] The foregoing process is consistent with Comparative Example 1, and the pay-off tension in the twisting step is adjusted from 19-20 kg to 16-18 kg.

[0078] After the lead machine is started, after the wire head passes through the traction wheel, the first sample of the embodiment and comparative examples 1, 2, and 3 is taken for conductor DC resistance detection. When the production at 80 m / min is completed, the last sample of the embodiment and comparative examples 1, 2, and 3 is taken for conductor DC resistance detection. The specific detection data are shown in Table 6.

[0079] Table 6 Comparison test data

[0080]

[0081] On the whole, the DC resistance of the conductors of the first and last samples of the embodiment and the comparative example all meet the GB / T3956 standard, and the DC resistance of the 240 cross-section conductor is ≤0.0754Ω / km. It can be seen from the embodiment and comparative example 1 that the decrease in annealing coefficient and the increase in take-up tension cause the increase in the resistivity of the single wire, the decrease in elongation and the decrease in the equivalent circular diameter of the drawn single wire, which ultimately leads to an increase in the resistance of the first sample of comparative example 1. The decrease in elongation makes it more difficult for the single wire of comparative example 1 to be thinned during the twisting process, so the change in the resistance margin of the conductors of the first and last samples of comparative example 1 is less than the change in the resistance margin of the conductors of the first and last samples of the embodiment. In addition, it can be seen from comparative examples 1 and 2 as well as the embodiment and comparative example 3 that, under the premise of keeping the drawing parameters and the rewinding parameters unchanged, reducing the pay-off tension can also avoid the thinning degree of the single wire during the twisting process and reduce the change in the resistance margin of the conductors of the first and last samples. In addition, it is also necessary to see that the change in the resistance margin of the conductor head and tail samples of Example 1 and Comparative Example 3 is greater than the change in the resistance margin of the conductor head and tail samples of Comparative Example 1 and Comparative Example 2. This is also because the elongation of the single wire in Comparative Example 1 and Comparative Example 2 is reduced, and it is more difficult to be pulled thin during the twisting process.

[0082] This embodiment takes a 240-section wire conductor as an example to introduce a method for producing a concentrically twisted special-shaped conductor; however, this method is not only applicable to a 240-section wire conductor, but can also be used for any 25-400-section wire conductor.

[0083] The above description is only a preferred embodiment of the present embodiment and is not intended to limit the present embodiment. For those skilled in the art, the present embodiment may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present embodiment shall be included in the protection scope of the present embodiment.

Claims

1. A method for producing a concentrically twisted special-shaped cable conductor, characterized in that: The production is completed based on the concentric stranding equipment, including the following steps: Select copper rods with mechanical properties, electrical conductivity, surface quality and diameter that meet the standards for the cable conductors to be produced; According to the equivalent circle diameter of the concentrically twisted wire monofilament in the cable conductor to be produced, the actual equivalent circle diameter of the finished wire drawing die is adjusted, and according to the inspection results of the wire monofilament, the annealing coefficient and the wire-winding tension are adjusted to complete the drawing of the wire monofilament; If and only if the equivalent circle diameter, resistivity and elongation of the obtained shaped wire monofilament all meet the preset standards, the rewinding process is entered; Rewinding the obtained plurality of shaped wire monofilaments onto the wire storage wheel at the same time; Adjust the pay-off tension and twist the rewound wire monofilaments. Pre-twisting is required during the twisting process. After pre-twisting, the production speed is evenly increased to form the cable conductor, thus completing the production of concentric twisted special-shaped cable conductors.

2. A method for producing a concentrically twisted special-shaped cable conductor as claimed in claim 1, characterized in that: The vertical frame is used for wire taking-up, and the capacity of the vertical frame is twice that of the wire taking-up reel, which reduces the number of reel changes and reduces labor intensity.

3. A method for producing a concentrically twisted special-shaped cable conductor as claimed in claim 1, characterized in that: During the process of drawing the molded wire monofilament, the annealing coefficient is adjusted so that the elongation of the molded wire monofilament is greater than 30%.

4. A method for producing a coaxially twisted special-shaped cable conductor as claimed in claim 1, characterized in that: Before twisting the rewound shaped wire monofilaments, the pay-off tension of the shaped wire monofilaments to be twisted is tested and adjusted to control the tension within a preset range and keep the pay-off tension uniform; after the pay-off tension adjustment is completed, the twisting of the shaped wire monofilaments is started.

5. A method for producing a concentrically twisted cable conductor as claimed in claim 4, characterized in that: After the pay-off tension is adjusted, the coaxial twisting device is started at a speed of 1 m / min to pre-twist the monofilaments of each layer of the wire. After the pre-twisting is completed, the speed of the coaxial twisting device is evenly increased.

6. A method for producing a concentrically twisted cable conductor as claimed in claim 4, characterized in that: After the pay-off tension is adjusted, the same production speed is maintained to reduce the resistance margin variation at the beginning and end of the conductor.

7. A method for producing a concentrically twisted cable conductor as claimed in claim 1, characterized in that: The preset standard is GB / T3953 standard; the equivalent circular diameter of the drawn wire is greater than the equivalent circular diameter of the process standard, that is, the equivalent circular diameter of the concentric stranded wire = the equivalent circular diameter of the standard process + Xmm, where 0 <X<0.04。 8. A method for producing a concentrically twisted cable conductor as claimed in claim 1, characterized in that: The concentric twisting equipment includes a single-reel mode and a double-reel mode. When the double-reel mode is adopted, the single wires of the cable conductor are twisted while being rewound during the production process of the cable conductor.

9. A method for producing a concentrically twisted cable conductor as claimed in claim 1, characterized in that: In the process of drawing the profiled wire monofilament, the concentration of the drawing liquid is controlled at 15% to 17%, and the pH value is controlled at 7 to 8.

10. A method for producing a coaxially twisted special-shaped cable conductor as claimed in claim 1, characterized in that: Use electronic scales and rulers to weigh, measure and calculate the equivalent circular diameter of the drawn wire single wire, and use resistance testers and tensile testing machines to test the resistivity and elongation of the drawn wire single wire.

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