JPS6014245Y2 - optical cable - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a fire-resistant optical cable that can guarantee highly reliable communication even in high-temperature environments.

BACKGROUND ART In recent years, as structures such as buildings and tunnels have become larger and more complex, measures are required to minimize damage when a fire occurs in these structures.

Particularly in the event of a fire, it is important to secure communication lines for controlling and commanding actions and measures for extinguishing fires, as well as communication lines for monitoring each part.

However, since such communication lines and communication lines for monitoring various parts are generally made of communication cables using copper wire, the plastic material part easily melts and burns due to high temperatures and high heat during a fire. Due to short circuits and fluctuations in capacitive coupling, the function as a communication channel is significantly degraded.

Further, in some cases, the copper itself may melt (melting point reaches 1083'C) due to the high temperature.

In the end, the problem remains that with telecommunication cables made of copper wire, it is difficult to guarantee the same communication function as at room temperature under high temperatures and high temperatures during a fire.

By the way, in communication cables for optical communication using optical fibers, the melting point of the quartz glass part that essentially contributes to signal transmission is as high as 1600°C, and there is no need to worry about short circuits.
It is considered to have better heat resistance than communication cables made of copper wire.

However, as shown in Figure 1, optical fibers (
The optical fiber (optical fiber core) 1 consists of a glass fiber 2 and a plastic coating 3 made of nylon, polyethylene, etc. to protect it, but even in communication cables using this optical fiber 1, the plastic used to protect the optical fiber is damaged due to high temperatures. The coating 3 may melt and burn, and in that case, the mechanical strength of the optical fiber will be reduced, and the optical fiber 1 will eventually break.

This invention was made in view of the above-mentioned current situation, and
The objective is to obtain a fire-resistant optical cable that can maintain reliable communication even in high-temperature environments.

The structure of the optical cable according to the present invention, which is a distant relative of this purpose, is that an optical transmission line using an optical fiber is inserted into a core pipe, and the core pipe is supported within an inner pipe made of refractory material via a spacer. The present invention is further characterized in that this inner pipe is supported within an outer pipe made of a refractory material via a spacer.

In other words, in this invention, an optical transmission line using optical fiber is surrounded by several refractory materials, and an air layer with low thermal conductivity is formed between the outermost refractory material and the outermost refractory material, which is directly affected by heat. This is intended to provide synergistic insulation of the optical transmission line.

Hereinafter, one embodiment of the optical cable according to the present invention will be described based on the drawings.

FIG. 2 shows a cross-sectional view of one embodiment.

One or more optical fibers 1 are housed as optical transmission paths in a narrow core pipe 4 made of iron, copper, aluminum, or the like.

An optical fiber cable may be passed through the core pipe 4 as an optical transmission path.

The core pipe 4 is inserted into an inner pipe 5 made of a refractory material, and is supported by a spacer 6 almost along the center of the inner pipe 5.

The spacer 6 is made of a refractory material such as a metal or a refractory inorganic material, and is approximately U-shaped in this embodiment.

The spacers 6 are arranged radially between the core pipe 4 and the inner pipe 3, support the core pipe 4 at their curved portions, and are installed at appropriate intervals in the axial direction of the pipes.

The shape of the spacer 6 is not limited to the U-shape, and various shapes can be considered, and the number of spacers 6 may be at least three at the supporting location.

By interposing the spacer 6, an air layer 7 is formed between the core pipe 4 and the inner pipe 5.

The inner pipe 5 is further inserted into an outer pipe 8 made of a heat-resistant material and is supported approximately at its center by a spacer 9.

The spacer 9 is similar to the spacer 6 described above, and due to the spacer 9, an air layer 10 is formed between the inner pipe 5 and the outer pipe 8.

The inner pipe 5 and the outer pipe 8 made of fireproof material may be made of metal such as iron, copper, aluminum, or an alloy thereof, or fireproof plastic.

Further, in this structure, in order to provide sufficient fire resistance, the outer diameter of the outer pipe 8 must be approximately five times or more the outer diameter of the core pipe 4.

As described above, there are refractory materials such as the core pipe 4, inner pipe 5, and outer pipe 8 around the optical fiber 1, and in addition, there are air layers 7 and 1o with low thermal conductivity.

Therefore, even if the optical cable is exposed to high temperatures due to a fire or the like, heat will not easily be transferred to the optical fiber 1.

As described above, according to the fire-resistant optical cable according to the present invention, a fire-resistant material and a heat insulating layer are provided around an optical transmission line using optical fibers to synergistically prevent the transfer of heat to the optical transmission line. Therefore, even in high temperatures and high-temperature atmospheres, the optical communication channel remains unchanged, and stable information transmission is guaranteed.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an optical fiber, and FIG. 2 is a sectional view of an embodiment of an optical cable according to the present invention. In the drawings, 1 is an optical fiber, 4 is a core pipe, 5 is an inner pipe, 6 and 9 are spacers, 7 and 10 are air layers, and 8 is an outer pipe.

Claims (1)

[Scope of utility model registration request] An optical transmission line using an optical fiber is inserted into a core pipe, and the core pipe is supported within an inner pipe made of refractory material via a spacer, and this inner pipe is then connected to an outer pipe made of refractory material via a spacer. An optical cable characterized by being supported inside.