JPH08138458A - Photo-electric power composite cable - Google Patents

Abstract

PURPOSE: To increase resistance against external damage and to reduce in a diameter dimension and in weight by arranging a clearance between an inner pipe, in which a conductive metal pipe storing an optical fiber in it is insulatedly coated, and an outside metal pipe, which is arranged on the outside of the inner pipe and is provided with excellent corrosion resistance and strength. CONSTITUTION: An optical fiber 1 is stored inside an inner pipe 2, in which an insulating coating 4 made of polyethylene or the like is applied on a conductive metal pipe 3 made of copper, aluminum, or the like. An outer pipe 5, which consists of a metal pipe made of stainless or the like having excellent corrosion resistance and strength or a corrugated pipe having bending resistance, is arranged on the outside of the inner pipe 2 via a clearance 6. In the outer pipe 5, a protection coating layer 7 made of polyethylene, urethane, nylon, or the like is arranged on the outer circumference, and an armor 8 such as an iron wire may be arranged additionally. In the clearance 6, cooling medium gas such as nitrogen gas or cooling medium liquid such as oil flows, so that the fiber 1 can be cooled. As the outer pipe 5 is made of metal, terminal connection to equipment can be carried out by welding or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical / electric power composite cable having a small diameter for transmitting information transmission by an optical fiber and electric power by one cable.

[0002]

2. Description of the Related Art FIG. 6 is a cross-sectional view of an example of a conventional optical and electric power combined submarine cable. As shown in the drawing, the optical fiber 21 is housed in a plurality of divided iron pipes 22, and a twisted layer 23 of a tensile strength piano wire, a conductive metal tube 24 such as copper or aluminum is placed on the iron pipe 22. Then, an insulating layer 25 made of low-density polyethylene and a protective layer 26 made of high-density polyethylene are applied.

[0003]

In the above-mentioned conventional optical and power composite cable, the outer diameter of the conductive metal tube is increased because a thick coating layer is provided on the outer side of the conductive metal tube for insulation and prevention of external damage. There is. Further, since the outer coating layer is a resin system, it is vulnerable to external damage, and when an external coating such as an iron wire is provided on the outer coating layer to protect external damage, there is a problem that the outer diameter is further increased and the weight is increased.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and provides an optical / electric power composite cable with a reduced diameter and weight, which is characterized by containing an optical fiber therein. Between the inner pipe and the outer pipe, the inner pipe having an insulating coating on the conductive metal pipe, and the outer pipe made of a metal pipe having excellent corrosion resistance and strength provided on the outer side of the inner pipe. Is to have a void.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a cross-sectional view of a concrete example of the optical / power composite cable of the present invention. As shown in the drawing, a single-core or multiple-core optical fiber 1 is housed in an inner tube 2 in which a conductive metal tube 3 such as copper or aluminum is coated with an insulating coating 4 such as polyethylene. If necessary, optical fiber 1 and inner tube 2
The gap may be filled with a jelly-like filler. An outer pipe 5 made of a metal pipe such as stainless steel having excellent corrosion resistance and strength is provided on the outer side of the inner pipe 2.
There is a space 6 between the outer tube 5 and the outer tube 5. If the cable is required to have high bending resistance, the outer tube 5 may be formed of a corrugated tube such as stainless steel having excellent bending resistance.

FIG. 2 is a cross-sectional view of another embodiment of the optical / power composite cable of the present invention. When used in applications requiring high tensile strength and external damage protection, such as submarine cables,
As shown in FIG. 2, a protective coating layer 7 of polyethylene, urethane, nylon or the like is provided on the outer circumference of the outer tube 5, and an outer sheath 8 of iron wire, steel wire or the like is further provided.

[0007]

Since the inner tube 2 for transmitting electric power is protected by the outer tube 5 having excellent corrosion resistance and strength, the insulating coating 4 can be thinned because only the electrical performance needs to be considered. Even if the outer tube 5 is broken due to external damage or the like, the insulation of the inner tube 2 is maintained. Although the outer pipe 5 has a tensile strength, since it is a double pipe, the inner pipe slides against the elongation of the outer pipe to absorb the elongation. When using for hanging or towing, it is necessary to increase the tensile strength, but in this case, polyethylene, urethane,
A protective coating layer 7 of nylon or the like may be provided, and an outer sheath 8 of iron wire, steel wire, or the like may be provided thereon. Further, in the case of the application of being repeatedly bent, the bending resistance can be improved by using the outer tube 5 as a corrugated tube as described above.

The space 6 between the inner pipe 2 and the outer pipe 5 can be used as a passage for the cooling medium. Since an ordinary optical fiber has a limit of about 80 ° C., when it is used in a high temperature environment higher than that, in the cable of the present invention, a gas such as nitrogen gas or a liquid cooling medium such as water or oil is filled in the gap 6. Sink, optical fiber 1
Can be cooled. At this time, there is a method in which a cooling medium introduced from one end is caused to flow out from the other end, or a cable is circulated in a loop. Alternatively, as shown in FIG. 3, the periphery of the optical fiber 1 in the inner tube 2 is also used as a cooling medium passage, and the gap between the inner tube 2 and the outer tube 5 is hermetically sealed 10 at the terminal portion. A through hole 9 may be provided near the end of the cooling medium 11 and the cooling medium 11 may be circulated through the through hole 9. This allows circulation of the cooling medium using only one end.

As shown in FIG. 4, a closed chamber 15 provided with a bellows 13 is attached to an end portion of the outer pipe 5, an insulating oil 12 is filled in a space 6 between the inner pipe 2 and the outer pipe 5, and a bellows 13 is formed. When it is used as a submarine cable to which high water pressure is applied by equalizing the external pressure with, the buckling of the outer pipe 5 due to water pressure can be reduced without increasing the wall thickness of the outer pipe 5 for applying water pressure. The insulating characteristic of the conductive metal tube 3 forming the inner tube 2 can also be improved. Reference numeral 14 is a through seal of the inner pipe 2.

FIGS. 5 (a) and 5 (b) are explanatory views of the structure of a terminal for connecting the optical / power composite cable of the present invention to a device. The conventional cable of FIG. 6 and the inner tube 2 provided with the insulating coating 4 of the present invention alone are difficult to fix to the device because the outside is resin. However, in the optical / electrical power composite cable of the present invention, since the outer tube 5 is made of a metal tube, the device 16
Can be fixed by welding 17 as shown in Fig. 5 (a), and if watertightness is required at the connection with the equipment 16 in the submarine cable, as shown in Fig. 5 (b), A ring seal 18 is also possible.

[0011]

As described above, the optical / power composite cable of the present invention has the following effects. (1) Since the inner tube that sends electric power is protected by the outer tube that has excellent corrosion resistance and strength, the insulation coating need only be considered in terms of electrical performance, so it is possible to make it thinner and reduce the diameter.
The weight can be reduced. (2) When it is necessary to increase the tensile strength of the cable,
It can be easily dealt with by providing a protective coating layer and an exterior on the outer tube. (3) When used in a high temperature environment, the optical fiber can be cooled by causing the refrigerant to flow through the space between the inner tube and the outer tube as the refrigerant passage. (4) In the terminal connection to the device, the structure is simplified by holding only the outer pipe by welding or O-ring seal.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a specific example of an optical / power composite cable of the present invention.

FIG. 2 is a cross-sectional view of another specific example of the optical / power composite cable of the present invention.

FIG. 3 is an explanatory diagram of a cooling method in which a gap between an inner tube and an outer tube of the optical / power composite cable of the present invention is used as a cooling medium passage.

FIG. 4 is an explanatory diagram in which a gap between an inner tube and an outer tube of the optical / power composite cable of the present invention is filled with insulating oil.

5 (a) and (b) are explanatory views of terminal connection of the optical and electric power composite cable of the present invention to a device.

FIG. 6 is a cross-sectional view of an example of a conventional optical and electric power combined submarine cable.

[Explanation of symbols]

 1 Optical fiber 2 Inner tube 3 Conductive metal tube 4 Insulation coating 5 Outer tube 6 Void 7 Protective coating layer 8 Exterior

Claims (4)

[Claims] 1. An inner tube having an insulating coating on a conductive metal tube having an optical fiber housed therein, and an outer tube made of a metal tube having excellent corrosion resistance and strength, which is provided outside the inner tube. The optical / electrical power composite cable is characterized by having a gap between the inner tube and the outer tube. 2. The optical / electrical power composite cable according to claim 1, wherein a cooling medium is caused to flow in a gap between the inner tube and the outer tube to cool the optical fiber. 3. The optical / power composite cable according to claim 2, wherein a through hole is provided in a part of the inner tube, and the inner tube and the outer tube are sealed at one end to allow a cooling medium to circulate. 4. The optical / power composite cable according to claim 1, wherein only the outer tube is retained in the equipment container when the terminal is connected to the equipment.