JPH05134125A - Gas dam part of optical coated fiber - Google Patents

Abstract

PURPOSE:To provide a gas dam part of an optical coated fiber for ensuring prevention of gas leaking through the optical coated fiber at low cost. CONSTITUTION:An aligned part 25, in which optical coated fibers 1 are arranged laterally in a line, is formed in the middle or on the end of an optical fiber cable, in which a plurality of the coated fibers 1, for which at least primary coating or secondary coating is provided on the outside of glass fiber, are stored, while a coat-removed part 26, for which the coating is removed, is formed on the coated fiber 1 of the aligned part 25, and an upper protecting plate 22 and a lower protecting plate 23 comprising the member of almost the same coefficient of thermal expansion as that of the glass fiber, are arranged and opposed to one another above and below the aligned part 25 including the coat-removed part 26. At least either one of the upper or lower protecting plates 22, 23 is formed into transparent plate, while the space between the aligned part 25 including the coat-removed part 26 and the upper and lower protecting plates 22, 23 is filled with an ultraviolet hardening bonding agent 24, and is hardened to form a gas dam part 21 of the coated fiber. The protecting plate can be provided only on one side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in a gas dam portion of an optical fiber cable for preventing leakage of gas through an optical fiber cable, and more particularly to an optical fiber core wire for preventing leakage of gas through the optical fiber core wire. Regarding the gas dam section.

[0002]

2. Description of the Related Art In recent years, an optical monitoring device using an optical fiber cable as a signal transmission line has come to be used for detecting the open / closed state of a gas insulated switch and for detecting a fault arc. However, in the gas-insulated switch equipped with this monitoring device, gas leaks to the outside through the optical fiber cable, and therefore it is necessary to provide a gas dam portion of the optical fiber cable to prevent this.

For example, a GI type optical fiber core wire is used for the optical fiber cable for this purpose. An example of the structure of the optical fiber core wire 1 will be described with reference to FIG. On the outside of the glass fiber 2, a primary coating 3 such as modified silicon having a thickness of several μm to several tens of μm is applied, a buffer layer 4 of silicon resin having a thickness of about 100 μm is provided, and nylon is extruded as a secondary coating 5. The outer diameter of the core wire 1 is 0.9 mm.

A large number of such core wires 1 are accommodated to form an optical fiber cable 11, which is introduced into a gas insulated switch. An example of the structure of the optical fiber cable 11 will be described with reference to FIG. The tension member 12 is the optical fiber cable 11
Located in the center of, bears most of the laying tension. The required number of optical fiber cores 1 are arranged around the tension member 12 with an intervening member 13 such as polypropylene yarn so as to have a substantially circular cross section (six in the illustrated example). A press-winding tape 14 is wound around the outer periphery of the core wire 1, a laminating tape 15 is vertically attached, and a polyethylene outer jacket 16 is covered to form the optical fiber cable 11.

When the optical fiber cable 11 is introduced into the gas insulated switch, since the optical fiber cable 11 itself has a structure in which gas leaks from the interposition 13, the outer sheath 16 and the like of the optical fiber cable is stripped for a predetermined length. Only the optical fiber core wire 1 and the tension member 12 are housed, for example, the end portion of the optical fiber cable and the bare optical fiber core wire 1 and the tension member 12 are housed in a stainless steel outer box, and the light is hardened with a polyurethane mixture. The gas dam portion of the fiber cable is formed.

[0006]

However, a slight gas leak was observed from the gas dam portion of the above-mentioned optical fiber cable. Upon pursuing the cause, it was found that gas was leaking from the optical fiber core, and it was leaking between the glass fiber and the primary coating of the optical fiber core, and between the buffer layer and the secondary coating. ..

The present invention was made in the search for the cause of slight gas leakage in the gas dam portion of the conventional optical fiber cable, and its purpose is to prevent gas leakage through the optical fiber core wire. It is an object of the present invention to provide a gas dam portion of an optical fiber core wire that can be reliably and inexpensively protected.

[0008]

In order to achieve the above object, the gas dam portion of the optical fiber core wire according to the present invention comprises a large number of optical fiber core wires provided with at least a primary coating and a secondary coating on the outside of the glass fiber. Forming an alignment part in which the core wires are arranged in a row in the middle or at the end of the optical fiber cable containing the book, and forming a coating removal part in which the coating of each core wire of the alignment part is removed, and removing the coating. The upper and lower protective plates made of a member having a coefficient of thermal expansion substantially equal to that of glass fiber are arranged to face each other above and below the aligned portion including the upper and lower portions, and at least one of the upper and lower protective plates is a transparent plate. The space between the aligning part including the removing part and the upper and lower protective plates is filled with an ultraviolet curing adhesive and cured. In addition, the protective plate is provided on only one side, and the space between the protective plate and the alignment part including the coating removal part and the core wire gap including the coating removal part on the other side are filled with an ultraviolet curing adhesive and cured. May be

[0009]

[Function] Since the UV-curing adhesive has good adhesiveness to glass, the space between the aligning part including the coating removing part and the protective plate (when the protective plate is only on one side, the core wire gap on the other side is Including)
The gas is prevented from leaking through the optical fiber by filling the optical fiber. Since the protective plate is made of a material having a thermal expansion coefficient substantially equal to that of the glass fiber, the glass fiber is not excessively strained due to the difference in the expansion coefficient from the protective plate. The coefficient of thermal expansion of the ultraviolet curable adhesive itself is different from that of glass fiber, but its rigidity is small, so it can sufficiently follow the expansion and contraction of glass fiber. When the upper and lower protective plates are provided, at least one of them is formed of a transparent member, so that it is easy to irradiate the ultraviolet curing adhesive with ultraviolet rays for curing the ultraviolet curing adhesive. When the protective plate is on only one side, irradiation may be performed from the side where the protective plate is not provided.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. 1A and 1B are views showing a gas dam portion of an optical fiber according to the present invention, in which FIG. 1A is a longitudinal sectional view and FIG. 1B is a transverse sectional view.

In FIG. 1, 1 is a GI type optical fiber core wire, 22 is an upper protective plate, 23 is a lower protective plate, and 24 is an ultraviolet curable adhesive, which form a gas dam portion 21 of the optical fiber core wire. ing.

The optical fiber core wire 1 is taken out by stripping off the jacket 16 and the like of the optical fiber cable, and as shown in the drawing, an alignment portion 24 in which six wires are arranged in a line is formed. In the section of the predetermined length L of the alignment section 24, the coating removal section 26 in which the primary coating and the secondary coating of each optical fiber core wire 1 are peeled off is formed.

The upper and lower protection plates 22 and 23 are quartz glass plates, at least one of which is transparent and can be irradiated with ultraviolet rays. The upper and lower protection plates 22 and 23 are arranged so as to sandwich the alignment portion 25 including the coating removal portion 26. In addition, the upper and lower protective plates 22, 23 of the quartz glass plate
Is the same material as the glass fiber of the GI optical fiber core,
The coefficient of thermal expansion is also substantially the same, and the transmission characteristics are not changed by giving an excessive strain to the glass fiber.

The UV curable adhesive 24 has a coating removing portion 26.
Space portion 27a, left and right portions 27b of the alignment portion 25, and the alignment portion 2
5 is filled so as to fill the space 27c between the optical fiber core wires. The UV-curable adhesive 24 includes, for example, Noland's No. 81 or No. 23.
1 is used. On the lower protection plate 23, the coating removal portion 26
The optical fiber core wires 1 on which are formed are arranged in a line to form the alignment portion 25, the ultraviolet curing adhesive 24 before curing is applied and the upper protective plate 22 is overlapped, and the protruding ultraviolet curing adhesive 24 is removed. Upper and lower protection plate 2 with a UV lamp, etc.
UV irradiation is performed through the transparent portions 2 and 23 to cure the UV curable adhesive 24, and the result is as shown in the figure. Although not shown, the protective plate may be provided on only one side. In this case, the core wire gap on the other side where the protective plate is not provided is filled with the ultraviolet curing adhesive, and the ultraviolet rays are irradiated from the side where the protective plate is not provided.

The gas dam portion 2 of the above-described optical fiber core wire 1
In No. 1, the gas that flows out through the gap between the glass fiber 2 and the primary coating 3 and the gap between the buffer layer 4 and the secondary coating 5 is blocked at the cured portion of the ultraviolet curing adhesive 24. The ultraviolet curing adhesive 24 has excellent adhesion to glass, and gas passing through this portion can be minimized. The coefficient of thermal expansion of the ultraviolet curable adhesive 24 itself is different from that of the glass fiber of the GI type optical fiber core, but since the rigidity is small, it can sufficiently follow the expansion and contraction of the glass fiber.

FIG. 2 shows a gas dam portion 3 of an optical fiber cable in which the gas dam portion 21 of the optical fiber core wire of FIG. 1 is incorporated.
It is sectional drawing of 1. The gas dam portion 31 is composed of an outer case 32 made of stainless steel and a filler 33 in the outer case 32. A flange 34 is fixed to the outer box 32 in a sealed state by welding or the like, a throttle 35 is formed on one end side, and the other end side is open. The optical fiber cable 11 is fitted into the diaphragm 35, and the inside of the outer box 32 is in a state of being separated by the optical fiber core wire 1 and the tension member 12. The gas dam portion 21 of the present invention is used in the middle of the optical fiber core wire 1. Then, in the state shown in the figure, it is solidified with a filler 33 such as a polyurethane admixture, and a seal member 36 is applied between the optical fiber cable 11 and the diaphragm 35 to prevent the passage of gas. The gas dam portion 31 is fastened to the case 36 of the switch with bolts 39 via packings 37 and 38. Gas dam part 2 of optical fiber
Gas dam part 3 of optical fiber cable when 1 is not used
The leakage of No. 1 was 10 cc or more in one year by filling SF6 (sulfur hexafluoride) gas of 1.5 atm, but when the gas dam part 21 of the optical fiber core was used, it was significantly less than 0.5 cc. Improved. That is, most of the conventional leakage was through the optical fiber core wire 1, but this was eliminated, and a minimum value of 0.5 cc or less as the entire gas dam portion 31 of the optical fiber cable was obtained.

[0017]

The gas dam portion of the optical fiber core wire of the present invention forms an alignment portion in which the core wires are arranged in a horizontal row, and a coating removal portion is formed by removing the coating of the core wire of the alignment portion, A protective plate made of a member having a coefficient of thermal expansion substantially equal to that of glass fiber is disposed on at least one side of the alignment portion including the coating removing portion, and when the protective plates are provided above and below, at least one is a transparent plate, and the coating removing portion is provided. The space between the alignment part including the protective plate and the protective plate (including the core wire gap on the other side when the protective plate is only on one side) is filled with an ultraviolet curing adhesive and cured. With a simple combination of UV curable adhesive,
It can prevent the leakage of gas through the core wire,
It can be easily incorporated into the gas dam part of a conventional optical fiber cable.

[Brief description of drawings]

FIG. 1 is a diagram showing a gas dam portion of an optical fiber according to the present invention.

FIG. 2 is a cross-sectional view of a gas dam portion of an optical fiber cable in which a gas dam portion of an optical fiber core wire is incorporated.

FIG. 3 is a cross-sectional view of an optical fiber cable.

FIG. 4 is a cross-sectional view of an optical fiber core wire.

[Explanation of symbols]

 1 Optical Fiber Core 21 Gas Dam Part 22 Upper Protective Plate 23 Lower Protective Plate 24 UV Curing Adhesive 25 Aligning Part 26 Coating Removal Part

Claims (2)

[Claims] 1. An alignment part in which the optical fibers are arranged in a horizontal row in the middle or at the end of an optical fiber cable accommodating a large number of optical fiber optical fibers provided with at least a primary coating and a secondary coating on the outside of the glass fiber. An upper protective plate formed of a member having a thermal expansion coefficient substantially equal to that of glass fiber formed above and below the alignment portion including the coating removal portion, the coating removal portion being formed by removing the coating of each core wire of the alignment portion; The lower protection plates are arranged so as to face each other, at least one of the upper and lower protection plates is a transparent plate, and the space between the alignment section including the coating removal section and the upper and lower protection plates is filled with an ultraviolet curing adhesive. The gas dam section of the optical fiber core that has been cured. 2. An alignment section in which the optical fibers are arranged in a horizontal row in the middle or at the end of an optical fiber cable that accommodates a large number of optical fiber optical fibers having at least a primary coating and a secondary coating on the outside of the glass fiber. Forming a coating removal portion where the coating of each core of the alignment portion is removed, and a protective plate made of a member having a thermal expansion coefficient substantially equal to that of glass fiber is arranged on one side of the alignment portion including the coating removal portion. The gas dam of the optical fiber core, which is provided and cured by filling the space between the aligning part including the coating removal part and the protective plate and the core wire gap including the coating removal part on the other side with the ultraviolet curing adhesive and curing it. Department.