JPS63292103A - Optical cable juncture of composite electric power-optical cable - Google Patents

Abstract

PURPOSE:To constitute a slender juncture of optical cables which withstands an external pressure, is highly watertight and is flexible by protecting the juncture of optical fiber cores with double constructions consisting of an external pressure protective pipe and water shielding pipe. CONSTITUTION:The external pressure protective pipe 19 which covers the juncture of the optical fiber cores 17 and the flexible water shielding pipes 20 fixed watertightly at both ends to the sheaths of the optical cables are provided to the junctures of the optical cables 12 housed in a composite electric power- optical cable. An interlock armor pipe 19 having crushing resistance and flexibility is put on the cable as the external pressure protective pipe and further, a lead pipe 20 is put as the water shielding pipe on the outside of the interlock armor pipe 19. Since both the interlock armor pipe 19 and the lead pipe 20 have sufficient flexibility, the slender juncture having the crushing resistance, watertightness and flexibility over the entire part is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a connecting portion of an optical cable housed in a power/optical composite cable.

[Prior art and its problems]

Figure 4 shows an example of a power/optical composite cable.

In the figure, 11 is an electric cable, 12 is an optical cable,
13 is a pressure tape, 14 is an m-loaded iron wire, and 15 is a sheath.

As shown in the diagram, in the power/optical composite cable, optical cable 1
2 is generally housed in a recess between adjacent power cables 11. When such a power/optical composite cable is extremely long, such as a submarine cable, it becomes necessary to provide a connection part for the optical cable 12 in the middle. Since the connecting portion of such an optical cable is housed within the composite cable, the following requirements are required.

■ The outer diameter should be as close to that of the optical cable as possible, and it should be flexible.

■ External pressure (lateral pressure during installation, water pressure when installing on the seabed, etc.)
to endure.

■ Good water barrier properties.

Normal optical cable connections use junction boxes to protect the optical fiber connections, but junction boxes are too large and inflexible, so they cannot meet the above requirements. .

[Means for solving problems and their effects]

The present invention has been made in view of the problems of the prior art as described above, and is directed to a flexible material that covers the connecting portion of optical fiber cores at the connecting portion of the optical cable housed in the power/optical composite cable. It is characterized by comprising an external pressure protection tube and a flexible water-shielding tube that is placed on the outside of the protection tube and whose both ends are watertightly fixed to the sheath of the optical cable.

With this two-layer structure of external pressure protection pipe and water-shielding pipe, the external pressure protection pipe only needs to be pressure resistant and watertightness is not required, so it is easy to make it flexible, and the water-shielding pipe only needs to be watertight. Since pressure resistance is not required, it is also possible to provide flexibility and satisfy the above requirements.

Note that if the external pressure protection pipe and the water shielding pipe are in close contact with each other, the flexibility is likely to be lost, so it is desirable to provide a suitable clearance between the two to allow for relative displacement.

〔Example〕

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

FIG. 1 shows a connecting portion of an optical cable according to an embodiment of the present invention, and although only one end of the connecting portion is shown, the other end has the same structure.

In this example, the sheath of the optical cable 12 is made of a lead sheath 16. At the connection part, the lead sheath 16 is peeled off to expose the optical fiber core 17 and the tensile run member 18, and the optical fiber core and the tension member 18 are connected to the other party's optical cable. Connecting run members. The connection portion of the optical fiber core 17 is wrapped with a non-woven fabric or the like if necessary, and then covered with a crush-resistant and flexible interlock armor tube 19 as an external pressure protection tube. Furthermore, a lead pipe 20 is placed over the outside of the interlock armored pipe 19 as a water-shielding pipe. An annular spacer 21 is fixed to the end of the lead pipe 20 in a watertight manner by a welding part 22 to keep it on the same axis as the optical cable 12, and the spacer 21 is watertightly fixed to the lead sheath 16 of the optical cable 12 by a welding part 23. Fixed.

According to the above configuration, since both the interlock armor tube 19 and the lead tube 20 have sufficient flexibility, an elongated connection portion that is crush resistant, watertight, and flexible as a whole can be obtained.

FIG. 2 shows another embodiment of the present invention, in which the external pressure protection tube in this optical cable connection section is composed of a number of tubes 24 divided in the longitudinal direction. The rest is the same as the embodiment shown in FIG.

Figure 3 shows another example of a structure in which the end of the lead pipe 20 is watertightly connected to the lead sheathing 16, in which the end of the lead pipe 20 is tapered and welded directly to the lead sheath 16. It is something. 25 is the welded portion.

In addition to the external pressure protection tube shown in the above embodiments, a spiral tube made of a metal strip wound in a spiral shape can also be used.

Further, in the above embodiment, a lead pipe is used as the water-shielding pipe, but the water-shielding pipe may be made of other materials such as plastic.

〔Effect of the invention〕

As explained above, according to the present invention, by protecting the connecting portion of the optical fiber core with a double structure of an external pressure protection tube and a water-shielding tube, it can withstand external pressure, has excellent watertightness, and is flexible. A connecting portion of a long and thin optical cable can be constructed by using the optical fiber, and an optical cable connecting portion suitable for being housed in a power/optical composite cable can be obtained.

[Brief explanation of drawings]

FIGS. 1 and 2 are sectional views showing an embodiment of the optical cable connection part according to the present invention, FIG. 3 is a sectional view showing another example of the structure of the lead pipe end in the same connection part, and FIG. FIG. 2 is a cross-sectional view of a power/optical composite cable. 11~Electrical cable, 12~Optical cable, 16~Lead sheathing,
17~optical fiber core wire, 18~tensile member, 19
~Interlock Armor? , 20 - lead pipe, 21 - spacer, 22 and 23 - welded part, 24 - pipe divided in the longitudinal direction. Figure 1 Figure 2 Figure 3 Figure 4

Claims (5)

[Claims] (1) A flexible external pressure protection tube that covers the optical fiber connection section that is housed in the power/optical composite cable, and a sheath of the optical cable that covers the outside of the tube and covers both ends of the optical cable connection section. An optical cable connection part of a power/optical composite cable, characterized in that it is equipped with a flexible water-shielding pipe that is watertightly fixed to the cable. (2) The connecting portion according to claim 1, in which the external pressure protection tube is made of an interlock armor tube. (3) The connecting portion according to claim 1, in which the external pressure protection tube is composed of a plurality of tubes divided in the longitudinal direction. (4) The connecting portion according to claim 1, in which the external pressure protection tube is made of a helical tube in which a metal strip is spirally wound. (5) The connecting portion according to claim 1, in which the water-shielding pipe is made of a lead pipe.