JPH0612921A - Power optical composite submarine cable - Google Patents

Abstract

PURPOSE:To provide a power optical composite submarine cable which can prevent the transmission loss or wire breaking by the small curvature of optical fibers at take of a coil. CONSTITUTION:An insulator 3 is provided on a conductor 2, which has an oil passage 1 at the center, and they are covered with a lead plate 4 and a corrosion preventive layer 4. On this corrosion preventive layer 5, interposed spacers 6 and metallic pipe cover optical units 7 are wound at the same time, and thereon a press tape 8 is wound. Furthermore, thereon an armor iron wires 9 and propylene yarns 12 are wound. In this power optical composite submarine cable, spacers 6 are disposed so that one piece each may come at minimum on both sides of the metallic pipe cover optical unit 7. Furthermore, the outside diameter of this spacer 6 is enlarged by about t=2mm more than the outside diameter of the metallic pipe cover optical unit 7, and besides these winding directions are put in the direction where it loosens at take of a coil. Hereby, even if the cable is twisted in an arrow direction at take of a coil, the metallic pipe 7a never shrinks.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite structure of a power and optical composite submarine cable.

[0002]

2. Description of the Related Art A power-optical composite submarine cable is coiled when it is manufactured and when it is loaded on a laying ship. When this coil is removed, the cable is 360
It will be twisted once.

In a power-optical composite submarine cable having a structure in which a metal-tube-coated optical unit is wound around an anticorrosive layer of the power cable, the power-cable is twisted when the coil is removed, so that the metal-tube-coated optical unit tends to be loosened. However, since there is a holding tape on the optical unit and it is necessary to have a structure to hold it firmly, it is possible to expand the excess length of the metal tube covered optical unit in the outer diameter direction when the power cable is twisted. It cannot escape and the metal tube of the optical unit shrinks. Even in that case, the length of the optical fiber in the optical unit does not change, so that there is a surplus in the length of the optical fiber in the metal tube.

[0004]

When the power cable is thus twisted, a small bend occurs in the optical fiber in the metal tube of the optical unit. When a bend smaller than the allowable value occurs, the signal loss transmitted through the optical fiber increases, and in the worst case, the optical fiber is broken. Therefore, it is necessary to have a power-optical composite cable structure in which the metal tube of the optical unit does not shrink even if the power cable is twisted by removing the coil.

The present invention has been made in view of the above circumstances, and it is possible to solve the above-mentioned drawbacks of the prior art and prevent an increase in signal transmission loss and disconnection due to a small bend in the optical fiber during coil removal. An object is to provide a novel electric power-optical composite submarine cable.

[0006]

Means and Actions for Solving the Problems
By placing an intervening spacer with an outer diameter of about 2 mm larger than this on both sides of the metal tube covered optical unit, a space is secured at the top of the optical unit so that the optical unit can move in the radial direction when the submarine cable is twisted. There is something I did. As a result, it is possible to prevent the optical unit metal tube from shrinking when removing the coil of the submarine cable, and to prevent an increase in signal transmission loss and disconnection due to a small bend in the optical fiber.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing a partially broken structure of the power-optical composite cable of the embodiment. That is, an oil passage 1 for flowing oil is provided at the center, and a conductor 2 and an insulator 3 for passing an electric current are provided around the oil passage 1. A lead coating 4 is formed on the insulator 3.
And the anticorrosion layer 5 is coated. An intervening spacer 6 and a metal tube coated optical unit 7 are simultaneously wound on the anticorrosion layer 5, and a holding tape 8 is wound on this.
An outer iron wire 9 and a polypropylene yarn 10 are wound around the pressing tape 8.

FIG. 2 shows an enlarged sectional view of a part of the metal tube-covered optical unit portion. In this figure, a floor layer 11 is provided on the anticorrosion layer 5 of the power cable provided inside. An optical unit 7 having a metal tube 7a coated thereon and an intervening spacer 6 having an outer diameter larger than this by about 2 mm are wound around the seat layer 11 together. At this time, the metal tube-covered optical unit 7 and the interposition spacer 6 are wound in a direction loosening with respect to the twisting direction shown by the arrow in FIG.

A pressing tape 8 is wound on the optical unit 7 and the intervening spacer 6, a polypropylene yarn 10 is wound on the pressing tape 8, and an outer iron wire 9 and a polypropylene yarn 13 are covered.

Therefore, a space t is secured around the metal tube-covered optical unit 7, and even if the metal tube-covered optical unit 7 is twisted in the arrow direction shown in FIG. Since the metal tube 7a does not shrink, the optical fiber accommodated therein does not have a small bend.

The size of the space t in the upper portion of the metal tube covered optical unit 7 is calculated under the standard conditions, and the result is as follows. That is, the winding diameter of the optical unit is 1
00mmφ, the winding pitch of the optical unit is 850m
m, the contraction rate of the optical unit metal tube when the optical unit is completely restrained under the condition that the coil take-up diameter is 8 mφ, and the looseness when the optical unit is completely free (increase in the winding diameter of the optical unit)
## EQU1 ## When the optical unit is completely restrained, the optical unit metal tube is compressed by about 0.4%. When the optical unit is free, the winding diameter of the optical unit is increased by 3.5 mm.

From this calculation, it is possible to prevent the optical unit metal tube from shrinking if there is a movement margin of about 2 mm above the optical unit.

Further, the intervening spacer along the optical unit is preferably made of a material which is not easily crushed by an external force, such as polyethylene, polyvinyl chloride, polyethylene terephthalate, nylon, iron, SUS and copper.

[0014]

As described above, according to the power-optical composite cable of the present invention, the metal tube-covered optical unit is wound around the cable anticorrosion layer, and the optical unit is generated when the cable is coiled. It is possible to prevent the contraction of the metal tube, and it is possible to obtain a power-optical composite cable that does not cause disconnection of the optical fiber and increase in transmission loss.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing the structure of a power-optical composite submarine cable according to an embodiment of the present invention,

FIG. 2 is an enlarged cross-sectional view of a portion of FIG.

[Explanation of symbols]

 1 Oil passage 2 Conductor 3 Insulator 4 Lead plate 5 Anticorrosion layer 6 Intervening spacer 7 Metal tube coating optical unit 8 Holding tape 9 Exterior iron wire 10, 12 Polypropylene yarn 11 Seating layer

Claims (1)

[Claims] 1. A power-optical composite submarine cable having a structure in which a metal tube-coated optical unit is wound around a cable anticorrosion layer, wherein at least one intervening spacer is arranged on each side of the metal tube-coated optical unit, and The power-optical composite submarine cable characterized in that the outer diameter of the spacer is larger than the outer diameter of the metal tube-coated optical unit by about 2 mm, and the winding direction of the intervening spacer is the direction in which the metal tube-coated optical unit is loosened when the cable coil is removed. .