JPS61292111A - Pressure resistant layer of submarine optical cable - Google Patents

Abstract

PURPOSE:To effectively prevent invasion of water by subjecting the mutual joint surfaces of sectorial divided metallic pieces and the inside peripheral surfaces thereof to satin finishing. CONSTITUTION:The divided metallic pieces 10a, 10b, 10c are so formed as to have approximately 120 deg. sectorial angle and ruggedness of about 0.005-0.02mm depth is formed to the inside peripheral surfaces 11a, 11b thereof to have the satin surfaces. The side faces 12a, 12b, (12c) to be joined with the divided metallic pieces 10a, 10b, 10c are also subjected to similar satin finishing. Such divided metallic pieces 10a, 10b, 10c of which the inside peripheral surfaces 11a, 11b, 11c and side faces 12a, 12b, 12c are subjected to satin finishing are formed longitudinally along an optical fiber unit and thereafter the outside peripheral surfaces thereof are brought into press contact with each other by wires with high tensile strength, then the side faces 12a, 12b, 12c of the respective divided metallic pieces 10a, 10b, 10c engage with each other and the adhesiveness of the joint surfaces is intensified.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to submarine optical cables using optical fibers as transmission media, and particularly relates to a pressure-resistant layer of submarine optical cables that protects optical fibers (units). be.

[Conventional technology]

Optical fibers have characteristics such as low loss, wideband performance, and light weight, so they are economically advantageous when used in submarine optical cables that transmit large amounts of information over long distances.

FIG. 6 shows an example of the cross-sectional structure of such a submarine optical cable, in which 1 is an optical fiber unit, 2 is the optical fiber unit) A metal protects 1 from high water pressure and is also used as a power supply path. This pressure-resistant layer 2 is 3
It is composed of divided fan-shaped individual pieces 2a, 2b, and 2c arranged vertically. Gap 3 in the pressure-resistant layer 2
is filled with a compound, and this compound is also filled in the pressure-resistant layer 2, the tensile strength wires outside the pressure layer 2, and the gaps 3 between the metal tubes, mainly to prevent water run-in. 4 is a tensile strength wire twisted around the outer periphery of the pressure layer 2, which mainly adds tensile strength to the submarine optical cable. 65 is a metal tube that fixes the tensile strength wire 4, and the compound is also applied to the gap 3 between these. Filled. 6 is an insulating layer made of plastic or the like.

Note that the outer periphery of the insulating layer 6 may be provided with an exterior covering to prevent damage to the cable, if necessary.

The characteristics of such submarine optical cables are as follows:
As described in Publication No. 1, the divided pieces 2a, 2b, and 2c constituting the pressure-resistant layer 2 have characteristics.

That is, since the pressure-resistant layer 2 is fixed to the outer periphery of the optical fiber unit with the divided pieces 2a, 2b, and 2C aligned vertically, it has a thickness that can sufficiently protect the optical fiber unit even under high water pressure. It has the advantage that it can be made thicker, and also has the advantage that the pressure-resistant layer is not heat-molded during manufacturing, so the transmission characteristics of the optical fiber are not impaired. Further, there are advantages such as being able to function as a tension member.

[Problem that the invention seeks to solve]

However, when forming the pressure-resistant layer 2, these divided pieces 2a, 2b, and 2c are required to be surface-finished with the highest possible accuracy so that no steps are formed on the inner and outer peripheral surfaces. Since the pressure-resistant layer 2 is constructed by vertically extending the pressure-resistant layer 2, when bending stress or the like is applied, the joint surfaces of the divided pieces 2a, 2b, and 2c will shift or fall, and as a result, the inside of the voltage-resistant layer 2 may There is a problem in that even if the compound is filled, the water running effect is not sufficiently exhibited. In particular, since it is not possible to apply a large pressure force to the optical fiber unit 1, the interlayer adhesion between the pressure-resistant layer 2 and the optical fiber unit 1 is low, and there is a fear of water run-through.
The bonding surfaces of the divided pieces 2a, 2b, and 2c forming the pressure-resistant layer 2 are also filled with compound, but there is a sufficient risk of water running on these bonding surfaces as well.

This invention was made in view of these problems, and provides a pressure-resistant layer for a highly reliable submarine optical cable that effectively prevents water run-through by applying a satin finish to the side surfaces of the divided pieces. .

〔Example〕

Fig. 1 shows the structure of the pressure layer of the submarine optical cable of the present invention, in which 10a, 10b, and 10c are three metal pieces each having a sector-shaped cross section, and the metal piece 10c is indicated by a dashed-dotted line. It is shown in

Each metal divided piece 10a, 10b, 10c has approximately 120 pieces.
The inner peripheral surface 11a is formed to have an opening angle of 6.
, llb, (lie) has a depth of 0.0 as shown.
By applying unevenness of about 0.05 to 0.02 mm, it is made into a satin finish, and in the same way, each of the metal divided pieces 10a, 10b, 10
The joining side surface 12a of c.

12b and (12c) are also given a similar satin finish.

These individual metal pieces 10a, 10b, and 10C are made by performing final forming by rolling with rolls as in the past, and applying a satin finish to the roll surface used in this rolling in advance by shot blasting. I can do it. For the degree of satin finish, when using a pressure-resistant layer with an inner diameter of 3.0 mmφ, for example, use Shoto Plus) #10 and set the number of satin finishes P to about 80 to 100 pieces/mrrf as shown in Fig. 2. preferable.

Inner peripheral surface 11a, llb, llc and side surface 12a.

These individual metal pieces 10a, 10b, and 10c, each having a matte finishing applied to 1, 2b, 1';'c, are formed vertically against an optical fiber unit, and then their outer peripheral surfaces are pressed together with a tensile strength wire. . Then, each metal divided piece 10a
, 10b, 10ccll) sides 12a, 12b.

12c are embedded into each other, and the adhesion of the joint surfaces is strengthened.

In this case, as shown in FIG.
Condensation may occur by Δθ on the satin finish of 12c, but in this case, depending on the degree of satin finishing, it is preferable to make the apex angle θ° of the metal divided pieces larger by ΔO. This condensation angle Δθ value is, for example, 0.00, although detailed calculation examples are omitted.
The angle may be 0.2° for a 2mm deep satin finish, 0.4'' for a 0.01mm deep satin finish, and approximately 0.8° for a 0.02mm depth.

As mentioned above, the pressure-resistant layer of the submarine optical cable of the present invention has a matte finish on the side surfaces of the individual metal pieces, so when the pressure-resistant layer is formed with such metal pieces, the interlayer adhesion between the individual pieces increases. However, even during cable molding or when bending stress is applied to the cable, there is no mutual depression (step) or shift between the divided side pieces, and the optical fiber unit 1 is sufficiently protected.

In addition, since the compound is filled in the matte finish, the water running path length is longer than that of the conventional pressure-resistant layer, and a higher water running prevention effect can be obtained.

The following table shows the outer diameter/inner diameter dimensions of the divided piece D (iron) as shown in Fig. 4, which is 8.1 mmφ/3. Ommφ, its length is 100mm, and the outer diameter of the optical fiber unit) P is 2.75a.
+ mφ, and a two-component temperature/room temperature curing type urethane resin is used as compound C to prevent water running. Drawing data using divided individual pieces, B is after satin processing (depth 0.02 mm, satin grain 80 ~
This is the drawing data (Kg/mm 2 ) using 100 pieces/m rn' of divided metal pieces.

0υ From this drawing data, while the conventional one has an average weight of 37.8Kg, the pressure-resistant layer of the present invention has an average weight of 75.3kg, which shows that the interlayer adhesion strength has increased by about twice.

As shown in Japanese Patent Application No. 59-65114, which was previously proposed by the present applicant, the metal divided pieces 20a, 20b, and 20c are interconnected, as shown in FIG. The present invention can also be applied to such types of pressure-resistant layers 20.

〔Effect of the invention〕

As explained above, the pressure-resistant layer of the submarine optical cable of the present invention is structured so that the side surfaces and inner circumferential surfaces of the divided metal pieces are satin-finished to protect the optical fiber unit. The adhesion between the pressure-resistant layer and the optical fiber unit is increased, the metal pieces no longer slide or fall into each other, and the effect of preventing the submarine optical cable from running in the water can be improved. .

[Brief Description of the Drawings] Fig. 1 is a perspective view showing the pressure layer of the submarine optical cable of the present invention, Fig. 2 is an enlarged plan view of the matte surface, and Fig. 3 is a vertical view of the pressure layer of the present invention. 4 is a perspective view of a submarine optical cable showing a sample for a pull-out test of an optical fiber unit, FIG. 5 is a cross-sectional view showing another example of a three-piece piece, and FIG. FIG. 2 is a cross-sectional view of a submarine optical cable in which three pieces are used as pressure-resistant layers. In the figure, 10a, 10b, and 10c are individual metal pieces forming a pressure-resistant layer, lla, llb, and llc are inner peripheral surfaces having a satin finish, and 12a and L2b. 12c indicates the side surface with satin finishing, and 0 indicates the opening angle. Figure 1 B Figure 2 (θ) Figure 3 Figure 5 Figure 6 Procedural amendments stamped) May 6, 1986

Claims (4)

[Claims] (1) In a submarine optical cable provided with a pressure-resistant layer formed of individual metal pieces with a fan-shaped cross section in order to protect the optical fiber, the joint surfaces of the fan-shaped metal pieces and the inner periphery A pressure-resistant layer for submarine optical cables characterized by a satin finish on the surface. (2) The fan angle of the individual metal pieces with satin finishing is 120.
The pressure layer of a submarine optical cable according to claim 1, wherein the pressure layer is set between 1 degree and 121 degrees. (3) In a submarine optical cable provided with a pressure-resistant layer formed of divided metal pieces having a fan-shaped cross section in order to protect the optical fiber, each of the fan-shaped divided metal pieces is interconnected; A pressure-resistant layer of a submarine optical cable characterized by having a matte finishing applied to the joint surface and inner peripheral surface. (4) The fan angle of the individual metal pieces with satin finishing is 120.
The pressure layer of a submarine optical cable according to claim 3, wherein the pressure layer is set between 1 degree and 121 degrees.