JPH07107571B2 - Waterproof optical fiber cable - Google Patents

Description

TECHNICAL FIELD The present invention relates to a waterproof optical fiber cable having an optical fiber ribbon.

[Prior art]

Conventionally, waterproof optical fiber cables having various structures have been proposed, and a typical one is as shown in FIG. As shown in FIG. 4, a plurality of optical fibers 1 (having an appropriate coating or not having any coating, in either case) are arranged in a plane in parallel, and A plurality of optical fiber tape core wires 3 coated with the collective coating 2 are housed in a laminated state in the groove 4 of the grooved spacer 5 having a spiral groove 4 on the surface thereof as shown in FIG. Form the optical fiber unit 6,
The optical fiber unit 6 is provided with a press winding 7 made of a plastic tape or the like as required, and a sheath 8 is provided on the press winding 7. The gap in the sheath 8 has a jelly-like waterproof admixture. It is filled with a waterproof material 9 such as a water-absorbing substance made of, for example, carboxymethyl cellulose, which swells into a gel when it absorbs water. In FIG. 3, reference numeral 10 is a strength member for reinforcing the grooved spacer 5.

By the way, in the waterproof type optical fiber cable shown in FIG. 3, the optical fiber tape core is provided in the grooved spacer 5 both when a waterproof jelly-like mixture is used as the waterproof material 9 and when a water absorbing material is used. It is most efficient to fill the wire 3 in a laminated state. However, in this case, since the flat surfaces are in close contact with each other in the gap between the laminated surfaces of the optical fiber ribbons 3, the waterproof material 9 does not sufficiently enter. As a result, there has been a problem that moisture that has entered from the outside runs along this laminated surface and penetrates deeply inside the cable.

[Object of the Invention]

In view of the above problems, an object of the present invention is to provide a waterproof optical fiber cable having an optical fiber ribbon, which has excellent waterproof characteristics.

[Structure of Invention]

In order to achieve the above object, the present invention provides an optical fiber tape core wire in which a plurality of optical fibers are arranged in parallel in the groove of a grooved spacer having a spiral groove on the surface and are collectively covered. A waterproof type optical fiber unit having an optical fiber unit in which a plurality of the optical fiber units are stacked, a sheath formed on the outer side of the optical fiber unit, and a waterproof material filled in a gap inside the sheath. In the cable, an oily substance is interposed between the plurality of laminated optical fiber tape cores.

Example of Invention

Hereinafter, the waterproof optical fiber cable of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an embodiment of the waterproof optical fiber cable of the present invention. As shown in the figure, in the present invention, a plurality of the above-mentioned optical fiber tape core wires 3 are provided in the groove 4 of the grooved spacer 5 having the spiral groove 4 on the surface thereof as shown in FIG. The optical fiber unit 6 is housed in a laminated state to form an optical fiber unit 6, and the optical fiber unit 6 is provided with a presser winding 7 made of a plastic tape or the like as required, and a sheath 8 is applied on the presser winding 7. The gap in the sheath 8 is filled with a waterproof mixture 9 such as a jelly-like waterproof admixture or a water-absorbing substance such as a polyacrylic acid type or a carboxymethyl cellulose type that swells and gels when absorbing water. In the waterproof optical fiber cable, the optical fiber tape core wire 3
As shown in FIG. 2, an oily substance 11 made of, for example, a synthetic oil such as silicone oil or polybutene oil, or a mineral oil such as naphthene oil is interposed on each laminated surface. Here, reference numeral 10 is a strength member made of steel wire or the like for reinforcing the grooved spacer 5, and is provided as necessary.
Further, the spiral groove 4 includes one in which the direction thereof is reversed at appropriate intervals. Further, as a method for interposing an oily substance on the laminated surface of each optical fiber tape core wire 3,
For example, the oily substance 11 may be applied to the surface of the optical fiber tape core wire 3 before the optical fiber tape core wire 3 is laminated.

In the waterproof type optical fiber cable of the present invention thus configured, since the laminated surface of the optical fiber tape core wires 3 is filled with the oily substance 11, it is difficult to fill the conventional waterproof material 9 and water running It is possible to completely prevent the water running between the optical fiber tape core wires 3 which was most likely to occur.

Specific examples of the present invention are shown below.

[Specific Example-1] Five optical fibers 1 having an outer diameter of 125 μm are arranged in parallel in a plane, and a collective coating 2 is applied to the optical fibers 1 having a thickness of 0.4 mm and a width of 1.6 mm as shown in FIG. The tape core wire 3 was obtained. In storing the optical fiber tape core wire 3 in a state of being laminated in each groove 4 of the grooved spacer 5 as shown in FIG. 1,
The pour point is -55 ° C and the viscosity at room temperature is 50 on the laminated surface of each core wire 3.
Cs silicone oil was applied. In this way, when the optical fiber tape core wire 3 having the laminated surface filled with the oily substance 11 is housed in the groove 4 of the grooved spacer 5, a perforated plastic tape is applied as the presser winding 7, and from the top of the presser winding 7. A petroleum-based waterproofing mixture having a consistency of 80 was press-fitted as the waterproofing material 9 and the sheath 8 was extrusion-coated.

A water pressure of 1 m height is applied to the cross section of the cable obtained in this way.
When the running length was measured over time, the running length was 10 cm.
And was extremely good. Also, the increase in transmission loss of the optical fiber 1 at a wavelength of 1.3 μm was 0.2 dB / km or less, which was also very good.

SPECIFIC EXAMPLE 2 Only the waterproof material 9 having the same structure as in SPECIFIC EXAMPLE 1 was changed to a water absorbent powder of polyacrylic acid type. Also, each optical fiber tape core wire 3
The same silicone oil as in Example 1 was applied to the laminated surface of the above.

As a result of performing a water running test on this cable cross section under the same conditions as in Example-1, the water running length was 10 cm or less, and the increase in the transmission loss of the optical fiber 1 was 0.2 dB / km or less at a wavelength of 1.3 μm. It was

〔The invention's effect〕

As described above, in the waterproof optical fiber cable of the present invention, water is not formed on the laminated surface of the optical fiber tape core wire, which has been a problem in the past, because the oily substance is filled between the laminated optical fiber tape core wires. You can completely prevent running. As described above, according to the present invention, it is possible to provide an optical fiber cable having extremely excellent waterproofness.

[Brief description of drawings]

FIG. 1 is a transverse sectional view showing an embodiment of the waterproof optical fiber cable of the present invention, FIG. 2 is an enlarged transverse sectional view of a laminated portion of the optical fiber tape core wire of FIG. 1, and FIG. 3 is a conventional example. FIG. 4 is a cross-sectional view showing an example of an optical fiber tape core wire. 1 ... Optical fiber, 3 ... Optical fiber ribbon, 4 ...
… Groove, 5 …… Grooved spacer, 9 …… Waterproof material, 11 …… Oil substance

Claims (1)

[Claims] 1. A plurality of optical fibers are arranged in parallel in a plane in the groove of a grooved spacer having a spiral groove on the surface thereof, and a plurality of optical fiber tape core wires coated collectively are laminated. A waterproof optical fiber cable having an optical fiber unit housed in a closed state, a sheath formed on the outer side of the optical fiber unit, and a waterproof material filled in an inner space of the sheath. A waterproof optical fiber cable, characterized in that an oily substance is interposed between a plurality of optical fiber tape cores.