JPH0362422A - Manufacture of watertight stranded conductor - Google Patents

Abstract

PURPOSE:To fill enough watertight material uniformly in a space between conductor wires without any gap by covering the conductor wires with a thermoplastic watertight material, stranding a plurality of the conductive wires while softening the watertight material with heating, and then immediately passing the stranded wires through a die for forming the circular external shape thereof. CONSTITUTION:A bobbin 3 with a conductor wire 1 covered with a thermoplastic watertight material 2 taken up, is mounted to a stranding machine and the thermoplastic watertight material 2 of the travelling wire 1 is softened at a position before conductor wire convergence in the upstream of a die 4. For example, a heating device 5 such as an infrared heater, a hot air supply and a high frequency induction heating device is provided. As a result, the thermoplastic watertight material 2 of the wire 1 is softened and filled into a stranded wire gap while being stranded and compressed at the position of the die 4. The excess of the watertight material 2 oozed on the external surface of the stranded wire is filled into a gap between outer stranded wires with the die 4 and the outer shape thereof is so formed as to be circular.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a method for manufacturing a watertight stranded wire conductor that prevents water from entering by filling gaps between conductor wires with a watertight material. Regarding,
do.

(Conventional technology) Cables used in submerged environments, such as undersea cables,
If there is a gap between the conductor strands, there is a problem in that if the cable is damaged in some way and water floods from that area, water will run inside the cable, increasing the damage caused by the damage to the cable.

Therefore, in cables used in such environments, the gaps within the cable are filled with a watertight material to prevent water from running in the event of an accident.

Conventionally, the watertight stranded conductor used in such cables consists of extruding a thermoplastic watertight material onto the center conductor strand, twisting other conductor strands around its outer periphery, and then cross-linking the strands onto the strands. The thermoplastic watertight material on the center conductor strand is softened by coating the polyethylene composition containing the agent, and passing it through a continuous crosslinked pipe to heat and crosslink the composition, softening the thermoplastic watertight material on the center conductor strand, and applying it to each conductor strand of the stranded conductor. It is known that the gaps between the strands are filled with the watertight material using the convergence force generated.

(Problem to be solved by the invention) However, in the conventional watertight stranded conductor as described above, it is not possible to apply sufficient tension to the stranded conductor because the cable needs to be suspended in a catenary shape within a continuous cross-linked pipe. Therefore, the convergence force generated in each conductor strand is also small,
There is a problem in that the watertight material often does not completely fill the gaps between the strands. Furthermore, for the same reason, the stranded wires do not converge sufficiently, resulting in the outer shape of the stranded wire conductor becoming distorted, which also causes damage to the appearance of the finished cable.

The present invention has been made to solve these conventional problems, and provides a method for manufacturing a water honey type stranded conductor that is evenly filled with a sufficient amount of watertight material without creating voids between the conductor wires. The purpose is to provide.

[Structure of the Invention] (Means for Solving the Problems) A first method of the present invention is to coat a conductor wire with a thermoplastic watertight material, and coat a plurality of conductor wires with the watertight material by heating. The second method is to twist the stranded wire conductor while softening it, and then immediately pass it through a die to form the outer shape into a nearly circular shape. , the watertight material is softened by heating while passing between a pair of guide rollers, and high tension is applied between the guide rollers to soften the watertight material by the convergence force generated in each conductor strand of the stranded conductor. It is characterized by filling the gaps between the twisted wires.

(Function) In the first method of the present invention, each of the conductor wires is coated with an appropriate amount of watertight material in advance and is twisted, so that the spaces between the twisted strands are completely filled with watertight material. In addition, since the outer shape is formed into a substantially circular shape by immediately passing through a die while the wire is in a softened state, the gaps between the outermost strands are also filled with the watertight agent due to the excess watertight material, and no unevenness occurs in the appearance.

In the second method, stranded wire conductors are twisted together with a thermoplastic watertight material interposed between the conductor strands, and heated while being passed between a pair of guide rollers to soften the watertight material and create a high tensile strength. , it is possible to apply sufficient tension to fill the watertight material between the conductor wires.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the state of each conductor wire 1 just before twisting in the embodiment of the first invention.
or a thermoplastic watertight material 2 having a high melt index (Ml value) such as ethylene-ethyl acrylate (EEA) based material is uniformly coated within a range of 0.1 to 11 m depending on the conductor wire diameter. The above-mentioned coating thickness is such that when the wires are twisted together in a softened state, the softened thermoplastic watertight material can completely fill the gaps between the twisted wires.

In this method, the bobbin 3 on which the conductor wire 1 coated with the thermoplastic watertight material 2 is wound is mounted on a twisting machine (not shown), and the bobbin 3 is placed in front of the die 4 of the twisting machine. A heating device 5, such as an infrared heater, hot air, or high-frequency induction heating device, is placed at a position before the conductor wires converge to soften the thermoplastic watertight material 2 of the running conductor wire 1. .

A conductor wire 1 covered with a thermoplastic watertight material 2 mounted on a wire twisting machine and running while being continuously unwound from a bobbin 3 is
The thermoplastic watertight material 2 is heated by the heating device 5 to soften it, is twisted and compressed at the position of the die 4, and is filled into the gap between the twisted wires. Further, the excess thermoplastic watertight material 2 protruding from the outer periphery of the stranded wires is filled into the outer stranded wire gaps by a die 4, and is shaped so that the outer shape thereof becomes circular.

Next, an embodiment of the second invention will be described with reference to FIG.

In this embodiment, in the stranded conductor 7, as shown in FIG. 4, the outer periphery of the central conductor strand 8 is coated with a thermoplastic watertight material 9 in advance. The thickness of the thermoplastic watertight material 9 is also set in accordance with the outer diameter of the conductor strands 8 to be a sufficient amount to fill the gaps between the strands.

The stranded wire conductor 7, which is continuously fed out from the stranded wire supply drum 10, is subjected to a high tension in the range below a preset yield point strength while passing through the accumulator 11 and reaching the metering 12. The first
The thermoplastic watertight material is softened by a heating device 13 similar to that in the invention, and then a polyethylene composition mixed with a crosslinking agent is coated on its outer periphery by an extruder 14, and suspended in a catenary shape inside a continuous crosslinked pipe 15. While moving, it is cross-linked and becomes a cross-linked polyethylene insulated wire. Winder 1
6.

In this embodiment, under the condition that no tension is directly propagated to the stranded conductor in the continuous cross-linked pipe 15 between the accumulator 11 and the metering 12 before entering the extruder 14, the stranded conductor is subjected to stress within the yield point stress. Since a high tension in the range of is applied, a high convergence force acts on each conductor strand, and the thermoplastic watertight material coated on the outer periphery of the center conductor strand is filled into the gaps between the strands by this convergence force.

In addition, in the above embodiment, an example was explained in which conductor tension was applied by an accumulator and a metering, but the present invention is not limited to such an embodiment. For example, it is possible to replace these with a dedicated capstan. You can.

[Effects of the Invention] As described above, according to the present invention, it is possible to manufacture a watertight stranded wire conductor that has superior watertight properties and has a good appearance.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the state of the thermoplastic watertight material coated on the conductor wire in the embodiment of the first invention, FIG. 2 is a diagram schematically showing the embodiment of the first invention, and FIG. FIG. 3 is a diagram for explaining the second invention in detail, and FIG. 4 is a diagram showing a cross section of the stranded wire before being processed by the method. 1.8... Conductor wire 2.9... Watertight material 3... Bobbin 4...・・・
・・・・・・・・・Dice 5.13・・・Heating device

Claims (2)

[Claims] (1) Covering a conductor wire with a thermoplastic watertight material, twisting a plurality of conductor wires by heating while softening the watertight material, and immediately passing them through a die to form an approximately circular outer shape. A method for manufacturing a watertight stranded wire conductor. (2) A stranded wire conductor, which is made by interposing a thermoplastic watertight material between the conductor wires, is heated while being passed between a pair of guide rollers to soften the watertight material, and a thermoplastic watertight material is interposed between the conductor wires. A method for manufacturing a watertight stranded wire conductor, characterized in that a high tension is applied and the watertight material is filled into the stranded wire gaps by a convergence force generated in each conductor strand of the stranded wire conductor.