JPH07114085B2 - Insulator with built-in optical fiber - Google Patents

Description

TECHNICAL FIELD The present invention relates to an insulator with a built-in optical fiber in which an optical fiber for transmitting a signal obtained from a power transmission line side to a ground side is embedded inside the insulator. is there.

(Prior Art) An optical fiber built-in insulator in which an optical fiber is penetrated through a through hole formed in an insulator body and fixed by a sealing material such as silicone rubber is disclosed in, for example, JP-A-60-158402. It has been known so far. This sealing material prevents leakage current from flowing along the surface of the optical fiber,
It is important for maintaining the surface leakage insulation distance of the insulator. However, since the through hole is elongated, it is difficult to keep the optical fiber correctly centered over its entire length, and the optical fiber may partially contact the inner surface of the through hole. In such a place, since the sealing material cannot enter between the optical fiber and the inner surface of the through hole, there is a drawback that water and moisture easily invade and the insulating property is easily deteriorated. Further, in such an insulator with a built-in optical fiber, when the temperature rises during use, the sealing material expands more thermally than the insulator body, and the insulator body may be damaged by the thermal stress.

Furthermore, when a plurality of such optical fiber built-in insulators are connected, in addition to the above problems, another problem arises as to how to process the joint end faces of the insulators. For this reason, the applicant previously invented a method of protecting an optical fiber by attaching a bendable connecting fitting to the joining portion of two insulators as disclosed in Japanese Patent Laid-Open No. 60-262104. However, there was a problem that the total length of the insulator was increased by the length of this connecting fitting. Therefore, an attempt was made to directly bond the end faces of the two insulators in close contact with each other, but the sealing material inside the through-holes oozes out to the bonding end face of the insulator, and when the temperature rises, the thermal expansion of the sealing material damages the insulator There was a risk of

(Problems to be Solved by the Invention) The present invention can solve the above-mentioned conventional problems and correctly hold an optical fiber at the center of an insulator body.
Also, the present invention provides a single or stacked type optical fiber built-in insulator that can easily seal an optical fiber with a sealing material and can prevent the insulator from being damaged even when thermal expansion occurs in the sealing material. It was completed for the purpose.

(Means for Solving the Problems) The first invention of the present application made to solve the above problems is a hollow donut made of an elastic material similar to the sealing material inside the through hole formed in the insulator body. -Shaped spacer is inserted, and an optical fiber is inserted inside the center hole and is sealed by a sealing material. The second invention of the present application made to solve the same problem in a stacked insulator device is similar to the sealing material around the through holes in the joint end faces of the plurality of insulator bodies having the through holes. A hollow donut-shaped spacer made of an elastic material is provided, and an optical fiber is inserted inside the center hole of the spacer and is sealed by a sealing material.

(Examples) Next, these inventions will be described in more detail with reference to Examples.

FIG. 1 shows an embodiment of the first invention, (1) is an insulator main body, (2) is a through hole formed in the center thereof, (3)
Is an optical fiber penetrating the inside of the through hole (2),
(4) is a sealing material made of a material such as silicone rubber filled in the through hole (2). In the present invention,
An appropriate number of spacers (5) are inserted inside the through holes (2). As shown in the enlarged view of FIG. 2, the spacer (5) has a hollow donut shape, and its outer diameter is slightly larger than the inner diameter of the through hole (2). The inside of the spacer (5) may be dry air, but SF _{6 has} high insulation.
Encapsulating gas etc. does not generate corona and is even better. The spacer (5) is made of an elastic material such as silicone rubber which is similar to the sealing material (4), and the optical fiber (3) is inserted into the center hole (6) of the spacer (5). , Is sealed by a sealing material (4) injected into the entire through hole (2) through the central hole (6).

When the hollow donut-shaped spacer (5) is used as described above, it is possible to easily and surely prevent the optical fiber (3) from coming into contact with the inner surface of the through hole (2), and the sealing material (4) has its center. Since the inside of the through hole (2) is filled through the hole (6) and solidified together with the spacer (5) made of the same material, the insulating property inside the through hole (2) can be enhanced. Also, since the spacer (5) is in close contact with the inner surface of the through hole (2) by its own elasticity, it is easy to position during assembly without misalignment, and the space between the sealing material (4) and the insulator should be avoided. It can also serve as a packing that prevents moisture from entering into the interior even when peeled off. Furthermore, when the sealing material (4) thermally expands during use, the hollow donut-shaped spacer (5) absorbs it due to its own elasticity and prevents damage to the insulator body (1) due to thermal stress. be able to.

3 and 4 show an embodiment of the second invention, in which (1) is an insulator body, (2) is a through hole,
(3) is an optical fiber, and (4) is a sealing material.
It is similar to the invention of. In the present invention, the plurality of insulator bodies (1), (1) are connected in series with the flange metal fittings (7), (7) in a state where their end faces are joined together. A hollow donut-shaped spacer (5) similar to that shown in FIG. 2 is arranged around (2). FIG. 4 is an enlarged view of this joint portion, in which the spacer (5) has a through hole (2).
The optical fiber (3) is inserted inside the central hole (6) of the taper expanded portion (8) at the end of the optical fiber. The material of the spacer (5) is first
Similar to the invention of (1), a material similar to the sealing material (4) such as silicone rubber is used. In addition, (9) and (10) are O-rings provided on the joint end surface of the insulator body (1) and the flange metal fitting (7).

By disposing the hollow donut-shaped spacer (5) on the joint end surfaces of the insulator bodies (1) and (1) in this way, the optical fiber (3) is positioned and protected by the spacer (5). In addition, the conventional connecting fittings are not required, the total length of the insulator device can be shortened, and the weight can be reduced and the bending strength can be improved. In addition, a plurality of insulator bodies (1) sandwiching the spacer (5),
Since the optical fiber (3) is inserted into the center hole (6) after the (1) is joined and the sealing material (4) is further injected to integrally seal, the sealing work is also easy. Is. Moreover, since such a spacer (5) is excellent in elasticity, it can prevent the sealing material (4) from exuding between the end faces of the insulator by acting like a packing, and the exuding sealing material (4) can be prevented. It is possible to prevent the insulator main body (1) from being damaged by the thermal expansion and to absorb the thermal stress at the time of thermal expansion by the elasticity of itself. By interposing the O-rings (9) and (10) on the joint end faces as in the embodiment, it is possible to reliably prevent moisture from entering the joint end faces from the outside.

(Effects of the Invention) As is apparent from the above description, the present invention uses the hollow donut-shaped spacer made of an elastic material of the same type as the sealing material to provide the case of the first invention made of a single insulator. Also, in the case of the second invention composed of a plurality of insulators, the optical fiber can be properly held at the center of the through hole to prevent the insulation from being deteriorated, the optical fiber sealing operation can be easily performed, and the thermal expansion This has advantages such as preventing damage to the insulator. Further, in the case of the second invention, since the connecting fitting can be omitted, the total length can be shortened and the bending strength of the entire insulator can be improved. Therefore, the present invention is extremely large in that it contributes to industrial development as an insulator with a built-in optical fiber that eliminates the conventional problems.

[Brief description of drawings]

FIG. 1 is a central longitudinal sectional view showing an embodiment of the first invention,
FIG. 3 is a partially cutaway perspective view showing a spacer, FIG. 3 is a central longitudinal sectional view showing an embodiment of the second invention, and FIG. 4 is an enlarged sectional view of a main part thereof. (1): Insulator body, (2): Through hole, (3): Optical fiber, (4): Sealing material, (5): Spacer, (6): Central hole.

Claims (2)

[Claims] 1. A through hole (2) formed in an insulator body (1).
A hollow donut-shaped spacer (5) made of an elastic material similar to the sealing material is inserted into the inside of the sealant, and the optical fiber (3) is inserted inside the center hole (6) of the sealing material (4). ) Insulators with a built-in optical fiber, which are sealed by. 2. A hollow donut made of an elastic material similar to the sealing material around the through holes (2) at the joint end faces of the plurality of insulator bodies (1) having the through holes (2) formed therein. -Shaped spacer (5) is provided, and the optical fiber (3) is inserted inside the central hole (6) and sealed by a sealing material (4). insulator.