JPH02216710A - Steel wire armored cable - Google Patents

Abstract

PURPOSE:To make it possible to insert a glass fiber line into a single core electric cable, undersea water supply pipe, etc., by making at least one of steel wires of steel armor a hollow steel wire of a specified cross sectional area ratio or greater and inserting the glass fiber into the hollow wire. CONSTITUTION:At least one steel wire 24A of a plurality of steel wires 24, while being of the same material with that of other steel wires 24B, is of a hollow cross section having a cross sectional area of 80% or more, into which a glass fiber core wire 26 is inserted. With the cross sectional area of the steel wire 24A being 80% or more of that of the steel wire 24B, lowering in the moment of inertia of its cross section is kept 5% or less. As a result, the steel wire 24A has almost the same mechanical strength with the wire 24B to prevent the core wire 26 from being damaged with external forces.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to improvements in iron wire armored cables having iron wire armor, such as submarine power cables or submarine water pipes.

(Prior Art) Submarine cables in a broad sense, such as submarine power cables or submarine water pipes, are armored with iron wire to protect the cable body. Such submarine cables are required to be attached with optical fiber cores that transmit control optical signals to operate the equipment connected to them, and composite submarine cables with optical fiber cores attached to them are required. Cables are already known.

(Problem to be Solved by the Invention) When a power cable has multiple cores, there is a gap between each core, so this gap can be used to insert the optical fiber. If it is a single core,
An optical fiber core cannot be inserted into a cable body, and an optical fiber core cannot be inserted into a long body of a submarine water pipe.

Regarding power cables, recently developed optical fiber cores with ultra-thin metal tubes are installed between the core of the power cable and the iron wire sheathing via a seat, etc., or placed between adjacent iron wires. However, since extremely large forces are applied to submarine cables from the outside, the optical fiber cores in ultra-fine metal tubes are crushed by the external pressure, resulting in increased transmission loss and damage to the optical fiber cores. cannot be invited or used.

SUMMARY OF THE INVENTION An object of the present invention is to provide an iron wire armored cable that avoids the above-mentioned drawbacks and allows optical fiber cores to be inserted into single-core cables and submarine water pipes without damage.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention provides a steel wire armored cable that includes a plurality of iron wires twisted together on the outer periphery of a cable main body such as a power cable or a water pipe. At least one of the iron wires is a hollow iron wire that is made of the same material as the other solid iron wire but has a cross-sectional area of 80% or more of the cross-sectional area of the solid iron wire, and at least one optical fiber is contained in the hollow iron wire. The present invention provides an iron wire armored cable characterized in that a core wire is inserted.

[Effect]

In this way, at least one iron wire of the iron wire sheathing is made hollow, and the optical fiber core wire is inserted into it, so that the insertion space for the optical fiber core wire can be easily secured, and this hollow iron wire has a cross-sectional area of Since the cross-sectional area is 80% or more of the cross-sectional area of other solid iron wires, the optical fiber core wire will not be damaged by external pressure.

(Embodiment) An embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a steel wire armored cable 10 according to the present invention.
In the present invention, the term "iron wire armored cable" is used in a broad sense to include not only cables in the original meaning such as submarine cables but also elongated bodies such as submarine water pipes which are coated with iron wire armor.

In the illustrated embodiment, the iron wire armored cable lO is a single-core cable, and the cable body 12 is composed of a conductor 14, an insulator 16 provided thereon, and a lead sheath 18 provided thereon. It is made. The iron wire armor 22 consists of a plurality of iron wires 24 twisted together on the outer periphery of a seat floor 20 provided on the lead sheath 18. These iron wires 24 are iron wires conforming to JIS 03532 and generally having an outer diameter of 3 to 100 mm.

At least one iron wire 2 among these plurality of iron wires 24
4A is a hollow iron wire that is made of the same material as the other solid iron wire 24B, but has a cross-sectional area of 80% or more of the cross-sectional area of this solid iron wire 24B, and there is at least one optical core in this hollow iron wire 24A. The fiber core 26 is inserted (Fig. 2 (
(See A)), this hollow iron wire 24A preferably has a coating layer 28 of plastic or paint on its outer periphery as shown in FIG. 2(B) for the purpose of preventing corrosion.
If a coating layer is provided on all the iron wires, the hollow iron wire 24A and the solid iron wire 24B, if the core of the hollow iron wire is damaged due to external injury, etc., the corrosion will concentrate there and the corrosion will progress in a short period of time. Coating layer 28 only on hollow iron wire with fiber core
It is preferable to apply this method. In this way, the bare solid iron wire acts as an electrode against electrolytic corrosion, which is the main cause of corrosion, and corrosion can be avoided from concentrating even if the hollow iron wire is damaged. .

In this way, at least one iron wire 24A of the iron wire armor 22
is made hollow and the optical fiber core wire 26 is inserted into it, so that the insertion space for the optical fiber core wire 26 can be easily secured.
If the cross-sectional area of 4B is 80% or more, the hollow iron @ 24A becomes a thick hollow iron wire, and the decrease in the moment of inertia of the cross section can be suppressed to 5% or less. Therefore, the hollow iron wire 24A becomes the same as the solid iron wire 24B. It has the same mechanical strength and the optical fiber core 26 will not be damaged by external pressure.

Figures 3 and 4 show different outer diameters (6mm, 8m).
The relationship between the inner diameter and the moment of inertia of two hollow iron wires with a ), the moment of inertia of area decreases rapidly, making it impossible to obtain the mechanical strength necessary to protect the optical fiber.

When the optical fiber core 26 in the hollow iron wire 24A is a single core, the connection part can be covered with a metal tube as usual and inserted into the hollow iron wire 24A together with this metal tube. In some cases, the connection part will be large, so use hollow iron wire 2.
However, by using a tape-shaped multi-core optical fiber core 26A as shown in FIG. 2(C), it can be inserted into the hollow iron wire 24A together with the connecting portion. Furthermore, if it is desired to insert a plurality of optical fiber cores 26, each 6 can be inserted into a separate hollow iron wire 24A. In this case, as shown in FIG. 1, it is preferable that the hollow iron wires 24A containing optical fibers are shifted at equal angular intervals in the circumferential direction. That is, when two hollow iron wires 24A containing optical fibers are used, If the wire is 180", it will be 120 degrees, and if there are 4 wires, it will be shifted by 90 degrees. In this way, even if the iron wire is damaged, all of the optical fiber cores will not be damaged. can.

Next, specific examples of the present invention will be described below. Iron wire armor using iron wire with an outer diameter of 8 mm and inner diameters of 1 mm, 2 mm, 3 mm, 4 mm, and 5 mm, and iron wire armor with an outer diameter of 6 mm and inner diameter of 1 mm and 2 m.
Regarding iron wire armor using iron wire of 3 mm, 3 mm, and 4 mm, a part of the iron wire is made hollow and an optical fiber core wire is inserted,
The armor including this hollow iron wire has a bending diameter of 300 mm and is 180 mm.
The results of the bending test were shown in the table below.

When the cross section of the hollow iron wire at the center of bending was observed in the above-mentioned test, it was found that the hollow iron wire into which the optical fiber core wire with increased transmission loss was inserted had become flat.

(Effects of the Invention) According to the present invention, as described above, at least one iron wire of the iron wire armor is made hollow, and the optical fiber core wire is inserted into the hollow core, so that the insertion space for the optical fiber core wire can be easily secured. Moreover, since the cross-sectional area of this hollow iron wire is 80% or more of the cross-sectional area of other solid iron wires, the optical fiber core wire will not be damaged by external pressure.

[Brief explanation of the drawing]

1st rf! I is a cross-sectional view of the iron wire armored cable according to the present invention, and FIGS. 2(A), (B), and (C) are enlarged cross-sectional views of one hollow iron wire used in the iron wire armored cable of FIG. 1, respectively. An enlarged cross-sectional view of another modified hollow iron wire and an enlarged cross-sectional view of a tape-shaped optical fiber core wire, FIGS. 3 and 4 respectively show the inner diameter and cross section of the hollow iron wire of two different sizes.
It is a diagram showing the relationship with the next moment. 10---One iron wire armored cable, 12---Cable body, 22---One iron wire armor. 24----One iron wire, 24A---Hollow iron wire, 24
B----1 solid iron wire, 26----optical fiber core wire. ;ゝranW1(to)%yas,)2A

Claims (1)

[Claims] In a steel wire armored cable having a steel wire armor made of a plurality of iron wires twisted together on the outer periphery of a cable main body such as a power cable or a water pipe, at least one of the plurality of iron wires is connected to another solid iron wire. The hollow iron wire is made of the same material but has a cross-sectional area that is 80% or more of the cross-sectional area of the solid iron wire, and is characterized in that at least one optical fiber is inserted into the hollow iron wire. Iron wire armored cable.