JPS637645B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a watertight conductor, in which the voids between the strands (constituent wires) in a stranded wire are filled with a watertight compound.

Conventionally, this type of watertight conductor has been manufactured by various methods, but the most common method is to press vinyl acetate (EVA)-based compound into a stranded conductor that has been preheated by induction heating etc. using a long die extruder. Alternatively, a liquid curing type compound is press-fitted into the stranded wire conductor using a long die pressurized with air (0.5 to 5 kg/cm ² ), and then immediately wrapped with semiconductive cloth tape to prevent liquid leakage. , methods of curing the compound by leaving it naturally or by heating are being used.

However, according to these methods, since the stranded conductor is press-fitted from the outside, the viscosity of the compound has a large effect on the smooth filling of the compound. Therefore, the composition of the compound is limited from the viewpoint of viscosity.For example, in order to improve electrical properties, it may be desirable to make a watertight compound semi-conductive, but if the amount of carbon added to make it semi-conductive increases, There was a problem in that the viscosity increased, making it impossible to press fit. In particular, vinyl acetate-based compounds require heating means and post-extrusion cooling means, and liquid room-temperature curing compounds require a tape winding machine as well as a curing process for the compound. In addition, in the case of the liquid room-temperature curing type of product, the adhesion was too strong, making it difficult to peel off the compound during work such as connecting conductors.

The present invention has been made in view of these conventional problems, and its purpose is to easily and sufficiently fill a stranded wire conductor with a watertight compound, and to provide the watertight compound with watertight properties as well as watertight properties. ,
An object of the present invention is to provide a method for producing a watertight conductor that can be provided with various useful properties.

Basically, the feature of the present invention is that when the stranded wires are twisted, a tape-shaped watertight compound is supplied to the running outer periphery of the conductor, and the compound is sequentially formed on the outer periphery of the center layer and on the outside of the center layer. The wires are twisted while being coated on the outer periphery of the outer layer, and the compound is filled into the gaps between the wires.

Hereinafter, one embodiment of the present invention will be explained in more detail with reference to the drawings.

FIG. 1 schematically shows a method for manufacturing a watertight conductor according to the present invention, in which the conductor is concentric and has three outer layers.

In the case of the present invention, first, a tape-shaped watertight compound 3 is applied to the outer periphery of the wire 2 fed out from the drum 1.
For example, it can be coated vertically (or wrapped).

After this, the first layer drum 4...the strands 5 drawn out from the group, the second layer drum 6...
Wire 7 drawn out from the group..., third layer drum 8
...The strands 9 drawn out from the group are twisted one after another, and at that time, tape-shaped watertight compound 3, 3 is applied to the outer periphery of the first layer and the outer periphery of the second layer in the same manner as above. supply and cover.

By coating the stranded wires with the watertight compound, the watertight compound 3 is inserted into the gaps between the wires, resulting in smooth and sufficient filling. Furthermore, the filling amount can be easily adjusted by changing the tape thickness.

Note that the outermost layer (third layer) does not need to be coated with compound 3 because the compound 3 inside will be extruded during heating and pressurization in the continuous crosslinking process described below, but in some cases , coating is also possible.

Here, the method of supplying and covering the watertight compound 3 is not particularly limited, but may be carried out using, for example, the apparatus shown in FIG. 2. That is, a tape-shaped watertight compound 3 is applied to the external reel 10, etc.
For example, as shown in FIG. 3, it is rolled up with a separator 11 such as a paper tape with good releasability,
When using this separator 11, pinch roll 1
2 and 12, and the watertight compound 3 is sent out by feed rolls 13 and 14 and supplied to the outer peripheral portion of the running stranded wire conductor. Then, at the outer circumferential portion of the conductor, the watertight compound 3 is applied by highly elastic rolls 15 to 18 made of sponge or the like installed vertically and horizontally (or in the radial direction).
The tape is pressed onto the outer circumference of the conductor in each direction sequentially,
It is covered in a wrapping manner. In this case, since the watertight compound 3 is in the form of a tape that can be wound around a reel, it is easy to handle, and in the case of vertical attachment, it can be coated without any special rotating means.

In addition, the watertight compound used is
In principle, any material can be used as long as it can be made into a tape, and there is no particular restriction in terms of viscosity as in the past, and a composition having various properties in addition to watertightness can be used. For example, carbon can be added to make it semiconductive. In other words, the degree of freedom in formulation can be increased. As for preferable characteristics, the continuous crosslinking process (180℃,
It has heat resistance that does not deteriorate due to oxidation after 15 minutes).
Volume resistivity is 5×10 ⁴ Ω due to semiconductivity
cm or less, and the Mooney viscosity is about 100 at 100°C because it can be extruded moderately by heating and pressurizing in the continuous crosslinking process. Specific examples of the formulation include butyl rubber as the base resin, petroleum as the adhesive, acetyl black as the carbon, paraffin as the lubricant, Vistanex as the softener, and the like.

The outer periphery of the watertight conductor filled with the watertight compound as described above is further covered with a presser tape 19,
For example, as shown in FIG. 4, a semiconductive cloth tape with carbon-containing butyl rubber 21, 21 pasted on the upper and lower surfaces of a base fabric 20 and a butyl rubber topping layer 22 on one side is used. is wound around the conductor side, and then, for example, the insulator 23 is wound around the conductor side.
Polyethylene containing a cross-linking agent is extruded and continuously cross-linked.

In this continuous crosslinking process, the temperature of the conductor part is 180℃ for about 15 minutes, and the internal temperature is about 9Kg/cm ²
subject to pressure. This reduces the viscosity of the watertight compound and increases its fluidity, while making it easier to move under high pressure. Therefore, the watertight compound is sufficiently packed into every corner of the gap between the wires, and a part of it is pushed out to the outermost layer of the conductor, forming the outermost layer (third layer) as shown in Figure 5.
The gap formed by the circumscribed circle is also filled with the compound 3, and it comes into close contact with the topping surface of the holding tape 19 on the conductor, resulting in an even more excellent watertight structure. In this structure, the filled watertight compound 3 is covered with a tape-like material, and the material itself can be made to have a composition with appropriate releasability, so it has good releasability and is suitable for products. It's hot,
Good workability when connecting conductors. Further, at this time, since heating and pressure are used in the crosslinking step, no special equipment is required.

Incidentally, in a watertight conductor manufactured in this way, for example, the insulator at approximately the center of a length of 10 m is removed, water is brought into direct contact with the outer periphery of the conductor, and a water pressure of 7 kg/
When a 24-hour watertight test was conducted at cm ² , no water infiltration into the conductor was observed.

The use of the watertight conductor manufactured according to the present invention is not particularly limited, but it is particularly effective when used as a power cable laid under the sea, and can also be used as an overhead electric wire.

As is clear from the above description, according to the method for manufacturing a watertight conductor of the present invention, the gap between the conductor wires is filled with the watertight compound smoothly and sufficiently, and the filling amount is adjusted. In addition, the conventional manufacturing process can be used without any special equipment other than the means for supplying and covering the tape-shaped watertight compound. In addition to the original watertight property, the material can be freely imparted with various useful properties such as semiconductivity, heat resistance, and appropriate releasability.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an outline of a method for manufacturing a watertight conductor according to an embodiment of the present invention, FIG. 2 is a schematic explanatory diagram showing an example of a watertight compound supply coating device,
Fig. 3 is a perspective view showing a tape-shaped watertight compound bonded to a separator, Fig. 4 is a longitudinal cross-sectional side view showing an example of a holding tape wrapped around the outer periphery of a conductor, and Fig. 5 is a watertight conductor manufactured according to the present invention. FIG. 2, 5, 7, 9...Element wire, 3...Watertight compound, 19...Holding tape.

Claims (1)

[Claims] 1. When twisting the strands, a tape-shaped watertight compound is supplied to the outer periphery of the center layer and the outer periphery of the outer layer formed outside the center layer, and the wires are twisted while being coated. A method for manufacturing a watertight conductor, characterized in that the voids between the strands are filled with a watertight compound. 2. When twisting the strands, a tape-shaped watertight compound is supplied to the outer periphery of the center layer and the outer periphery of the outer layer formed outside the center layer, and the wires are twisted while being coated, and then the outermost layer is A method for producing a watertight conductor, characterized in that a pressure tape is wound around the outer periphery of the conductor, and then the watertight compound and the pressure tape are brought into close contact with each other by heating and pressurizing. 3. The method for producing a watertight conductor according to claim 1 or 2, wherein carbon is blended into the watertight compound to make it semiconductive.