JPH02168805A - Subaqueous cable provided with joint - Google Patents

Abstract

PURPOSE:To eliminate crane operation when a cable is sunk to water bottom and to protect the cable from damage by arranging a buoy at a joint. CONSTITUTION:The joint 12 of an a subaqueous cable 11 is mainly composed of a joint core 13 including power lines and communication lines connected each other, an anchor metal 14 and a tension member 15, where a buoy 16 is covering the outer circumference of the joint 12. The buoy 16 has a double cylinder buoyant tank comprising a buoy 16, an inner tube 17, an outer tube 18 and an end plate 19, where a reinforcing pole 20 is arranged between the inner and outer tubes 17, 18. Since buoyancy is provided at the joint 12 of a subaqueous cable 11 through the buoy 16, weight in the water at the joint 12 of the subaqueous cable 11 is approximately equal to that of other sections and thereby the cable sinks smoothly without requiring crane operation, resulting in improvement of workability and prevention of damage.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application J] The present invention relates to an underwater cable with a connecting portion installed on the bottom of a seabed, a river bed, or the like.

``Conventional technology 1 Underwater cables, especially submarine cables, are becoming higher voltage and longer distances year by year, and their power transmission capacity is also increasing.

Under these circumstances, even a single accident can become a major problem, so it is essential to inspect and repair cables before anything serious happens.

When a defective or defective part that could cause an accident is detected in an underwater cable, that part is repaired or cut out and connected.

Such cable repair and cable connection are carried out on a work boat, and after the connection work is completed, the underwater cable is sunk to the bottom of the water from the work boat and re-installed.

FIG. 3 shows the situation in which the connected underwater cable is laid from the work boat to the underwater bottom.

In FIG. 3, a bottom cable C with a connecting portion J is thrown into the water from a work boat S moving in the direction of the arrow, and descends while drawing a catenary curve to reach the bottom G.

"Problem to be Solved by the Invention" However, in the case of the underwater cable C mentioned above, the connecting part J is extremely heavy and there is a considerable weight difference between the connecting part J and the other parts, so the underwater cable C has a catenary curve. It settles without any appearance.

By the way, before the underwater cable C that has been thrown into the water lands on the underwater bottom G, the connecting part J sinks vertically as shown in Figure 4, so there is a harmful L-shaped bend at 21 points of the underwater cable C. When the connecting part J lands on the bottom G and falls horizontally, a harmful L-shaped bend occurs at 22 points of the bottom cable C, as shown in FIG.

As a countermeasure for this, bottles were made on the work boat S-J-.
Although it has been implemented to suspend and support the connecting part J by a /-n to hold the underwater cable C in a catenary curve during subsidence, it is difficult to implement such a measure in a water area of high water depth.

In view of these problems, the present invention seeks to provide an underwater cable with a connecting portion that can be made to sink in a catenary state when the cable is installed on the underwater bottom.

``Means for Solving the Problems j'' In order to achieve the intended purpose of the underwater cable with a connecting part according to the present invention, a floating body is provided at the connecting part of the underwater cable, and It is characterized in that the weight in water and the weight in water per unit volume of the other parts are approximately equal to each other.

In the case of the underwater cable according to the present invention, the underwater weight (per unit volume) of the connection part where the floating body is provided and the underwater weight (per unit volume) of the other parts are almost equal to the underwater weight (per unit volume). When laying the cable to
The underwater cable can be settled in a catenary curve, and no harmful bending occurs in the underwater cable.

"Example" Regarding the example of the underwater cable with connection part according to the present invention,
This will be explained with reference to the drawings.

In FIGS. 1 and 2, the underwater cable 11 is made of a cable well known in the electrical field, such as an electric cable, a communication cable, or a composite cable of an electric cable and a communication cable.

The connecting portion 12 of the underwater cable 11 includes a connecting portion core 13 including interconnected power lines and/or communication lines, a retaining metal fitting 14 attached to both sides of the connecting portion core 13, and a connecting portion 12 extending over the connecting portion core 13 including interconnected power lines and/or communication lines. The connecting portion 12 is mainly configured with an installed tension member 15 made of metal or FRP, and the connecting portion 12 is provided with a floating body 16 that covers the outer periphery thereof.

The illustrated floating body 18 has a double-cylindrical buoyancy tank structure composed of an inner mantle 17, an outer mantle 18, and an end plate 18, and there is a space between the inner mantle 17 and the outer mantle 18 to improve pressure resistance. Reinforcement pillars 20 are provided scattered for this purpose.

In addition, the floating body 16 is provided with an injection hole 21 for compound that penetrates the inner mantle 17 and the outer mantle 18.
1 is equipped with a stopper 22.

As the material of the members constituting the floating body 16, for example, metal, synthetic resin (including FRP), etc. are adopted.

As described above, this floating body 16 is arranged so as to cover the outer periphery of the connecting part 12, and through the flanges 23 attached to the outer periphery of each boundary between the connecting part 12 and the non-connecting part,
Fixed in place.

The connecting portion 12 is filled with a compound 24 made of rubber or synthetic resin that is injected from the injection hole 21 into the suspension 17 of the floating body 16, and the injection hole 21 is provided with a plug 22.

In addition, in the underwater cable 11, a bending restriction member (pendle lifter) is provided on the outer peripheral portion adjacent to the flange 23.
25 is covered.

As mentioned above, the connection part 12 of the underwater cable 11 includes:
Since buoyancy in the water (in the sea) is applied via the floating body 16, the underwater weight (
(per unit volume) and the underwater weight (per unit volume) of the other parts are approximately equal to each other.

When the floating body 16 satisfies the above-mentioned conditions regarding the underwater weight, the floating body 16 may be made of a member that generates buoyancy in water, such as foamed plastic, instead of the illustrated buoyancy tank structure.

Preferably, the compound 24 also has a closed cell structure that provides buoyancy in water.

In addition, when the outer periphery of the connecting portion 12 is covered with a single cylindrical body, a hollow body may be interposed within the cylindrical body, or,
The required floating body can also be constructed by interposing foamed plastic (closed cell structure).

Since the underwater cable 11 of the above-described embodiment has the floating body 16 provided at the connecting portion 12, it sinks to the bottom of the water (seafloor) while drawing a catenary curve, as described above.

Therefore, when the cable is laid on the bottom of the water, bending that would adversely affect the bottom cable is not caused.

"Effects of the Invention" As explained above, since the underwater cable with a connection part according to the present invention is provided with a floating body that generates a predetermined underwater buoyancy force at the connection part, it can be easily operated without the need for difficult crane operations. Depending on the floating body, the underwater cable can be easily lowered to the ocean floor, and in turn, the underwater cable can be laid on the ocean floor without being damaged.

Moreover, since the weight of the connection part underwater is not reduced by omitting the connection member, the strength of the connection part is not reduced.
Sufficient durability of the connection portion can be ensured.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional front view showing one embodiment of an underwater cable with a connecting portion according to the present invention, Fig. 2 is a longitudinal sectional side view of the same, and Figs. 3, 4, and 5 are various types of underwater cables. FIG. 2 is an explanatory diagram schematically showing the installation situation. 11...Bottom cable 12...Connection part 1B...Floating body agent Patent attorney Yoshio Saifuji

Claims (1)

[Claims] An underwater cable with a connecting part, characterized in that a floating body is provided at the connecting part of the underwater cable, and the underwater weight per unit volume of the connecting part and the underwater weight per unit volume of the other parts are almost equal to each other. .