JPS6016003Y2 - submarine cable - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of the exterior of a submarine cable.

Conventionally, in submarine cables laid under the seabed, iron wire is usually used as the outer sheath to protect against external damage and maintain mechanical strength during installation and hoisting.

However, bare iron wire is directly subject to corrosion due to tidal electromotive force, induced voltage, or stray current from electric railways, and it is expected that the iron wire will soon become unusable. This prevents damage caused by electrolytic corrosion.

(1) Apply tar.

(2) Wrap the jute around it.

(3) Coating plastisol.

(4) Cover with polyethylene.

However, since these anti-corrosion materials are all composed of insulators, if a defect occurs in the insulation coating, the iron wire will come into direct contact with seawater, and the coating resistance of the iron wire will decrease at this defective part. The current suddenly decreased, and the current flowed out into the seawater, causing localized corrosion and premature breakage of the steel wire, often causing major accidents.

The present invention was discovered as a result of intensive research into preventing electrolytic corrosion of armored iron wire.

That is, the present invention has the following features: (1) In a submarine cable with an exterior made of iron wire armor and anticorrosion layer, a semiconducting layer is provided on the outside of the bare iron wire, the armor is formed of the semiconducting layer coated iron wire, and jute is coated on the outside of the semiconducting layer. It is equipped with an anti-corrosion layer such as

(2) A semiconductive paint, a semiconductive mixture, or a semiconductive cloth containing at least one conductive substance selected from carbon black, zinc, magnesium, or an alloy thereof on a semiconductive base material as a semiconductive layer. It consists of tape.

In the present invention, a resin composition containing a polyolefin copolymer of polyethylene, polyvinyl chloride, butyl rubber, etc. is used as the semiconductive base material.

Further, as the conductive substance, conductive carbon black, Mg,
Zn metal powder or metal oxide powder, or Mg-Zn, Z
n-A1 alloy powder (hereinafter simply referred to as metal powder) is used.

Note that the metal powder is a metal that is baser than iron, and is mixed in to play the role of a sacrificial anode.

Therefore, the metal not only acts as a semiconductor to relax the electric field on the iron wire, but also acts as a sacrificial anode to actively prevent corrosion of the iron wire itself.

In addition, the content of metal powder is 10% of the polyolefin copolymer composition.
The amount is 40 to 1 part by weight, preferably 50 to 8 parts by weight.

When the semiconductive layer is provided by paint, a water-soluble solution is usually used in which water is added to a water-soluble resin such as polyvinyl alcohol, and the above-mentioned conductive substance is mixed therein.

In the case of providing a mixture, the above-mentioned conductive substance is kneaded into an asphalt compound or a polybutene compound.

In the case of providing it with a cloth tape, a vulcanized chloroprene rubber-coated semiconductive cloth (4), for example, a nylon cloth is used as a support, and a rubber compound kneaded with the above-mentioned conductive substance is applied to both sides of the support, followed by heating and vulcanization. Semiconductive cotton cloth (B) coated with vulcanized chloroprene (B) For example, chloroprene rubber made by kneading the above-mentioned conductive substance on both sides of a support made of a cotton cloth such as a cotton cloth or a bleached cotton cloth made by bleaching and calendering these materials. was applied uniformly and heated and vulcanized.

In addition, the present invention may provide a steel wire armor by providing the above-mentioned semiconductive layer on the outside of a bare wire and providing a plastisol layer or a polyethylene layer on the outside.

Note that the thickness of the semiconductive layer is preferably in the range of 0.1 to 577EI71, although it varies depending on the capacity of the cable.

Next, embodiments of the present invention will be described in detail with reference to the drawings.

Example 1 As shown in Fig. 2, a galvanized iron wire of <81rIMφ 2゜2
′, 2″ Zinc powder (-10
0 mesh) A semiconductive paint consisting of 4 parts by weight of polyvinyl alcohol, 5 parts by weight of water was applied to a film thickness of 1 mm to form a semiconductive layer 3. A submarine cable of the present invention was obtained by forming a steel wire armor device by providing a steel wire armor device with 3′ and 3″, and providing an anticorrosive layer 4 made of No. 14 jute 6 and asphalt compound 5 on the outside.

Example 2 As shown in Fig. 3, galvanized iron wires 2° 2', 2
A mixture consisting of 6 parts by weight of acetylene carbon black, 1 part by weight of stearic acid, and 3 parts by weight of 4,4-thiobis-(6-tert-butyl-3-methylphenol) was added to the outside of the EVAIO part. A semiconductive layer 3.3', 3'' is coated to a thickness of 0.1 mm, and a polyethylene layer 7.3' is provided on the outside thereof.
7' and 7'' were coated to a thickness of 1 rrgn to form a steel wire armor device, and an anti-corrosion layer 4 made of polypropylene yarn 5 and asphalt compound 6 was provided on the outside to obtain the submarine cable of the present invention.

Comparative Example 1 A conventional submarine cable was obtained by applying a iron wire armor device using only 2.2' and 2'' galvanized iron wires of 8rrrmφ.

Comparative Example 2 As shown in Figure 1 <8rIrI! tφ galvanized iron wire 2
A conventional submarine cable was obtained by providing an anti-corrosion layer 4 made of jute 5 and asphalt compound 6 on the outside of the iron wire armor made of ゜2', 2''.

After immersing the submarine cable of the present invention and the conventional submarine cable in seawater for 2 years with no bare electrodes for 2 m, constant voltage electrolysis was carried out for 1 month by applying 10 V DC in a water tank. The corrosion rate was estimated by measuring weight changes before and after the meal.

The corrosion rate is (W□-W2)/W□×100% (where Wl is the weight before electrolytic corrosion (g), W2 is the weight after electrolytic corrosion (f)
) The results are shown in Table 1.

As is clear from the above table, the submarine cable of the present invention has remarkable effects such as being able to be used for a long period of time because the electrolytic corrosion caused by seawater is extremely low.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a conventional submarine cable, Figures 2 and 3
The figure is a sectional view showing an example of the submarine cable of the present invention. 1... Iron wire armor, 2.2', 2''...
Galvanized iron wire, 3.3', 3''...Semiconductive layer, 4...Anti-corrosion layer, 5...Jute, 6
...Asphalt compound.

Claims (1)

[Scope of utility model registration request] A submarine cable with an exterior made of iron wire armor and an anti-corrosion layer, in which the armor is formed from semi-conductive layer-covered iron wire with a semi-conductive layer provided on the outer periphery in advance, and an anti-corrosion layer is provided on the outside of the armor.