JPH05142455A - Heat resistant communication cable - Google Patents

Abstract

PURPOSE:To obtain the heat resistant communication cable which enables an internal communication wire to maintain its intrinsic function without causing a heat insulating material to compress the communication wire even when the heat resistant communication cable to be used in high-temp. environment is subjected to bending by a laying operation, etc. CONSTITUTION:The communication cable is constituted of an inner pipe 2 which has the inside diameter sufficiently larger than the outside diameter of the communication wire and is inserted with the communication wire 1 in its hollow part and an outer pipe 4 which is provided to cover this inner pipe 2 and holds the heat insulating material 3 between the outer pipe and the inner pipe 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat resistant communication cable used in a high temperature environment, and more particularly to an improvement of a communication cable in which the periphery of the communication line is covered with a heat insulating material.

[0002]

2. Description of the Related Art Conventionally, as a communication cable having heat resistance, as shown in FIG. 4, an insulating material 7 such as ceramic powder is provided around a communication line 6 such as an optical fiber cable for transmitting information or a conductive wire. It is known that the heat insulating material 7 is covered with a covering pipe 8 made of stainless steel or the like. In this communication cable, since the communication line 6 is covered with a material having low thermal conductivity such as ceramic powder, it is difficult for heat to be transmitted to the internal communication line 6, and the communication line 6 is effectively protected in a high temperature environment. It is possible.

[0003]

However, in the above-mentioned conventional communication cable, since the heat insulating material is filled without a gap between the communication wire and the covering pipe, the communication cable is bent during laying work or the like. If this is done, there is a drawback in that the heat insulating material presses the communication line. Therefore, for example, when the communication line is an optical fiber cable, the transmission loss increases, which causes a problem that the original function of the communication line is impaired.

The present invention has been made in view of the above problems, and an object of the present invention is that an external force acts on an internal communication line even when bending is performed by laying work or the like. Another object is to provide a heat-resistant communication cable capable of maintaining the original function of the communication line.

[0005]

In order to achieve the above object, the heat resistant communication cable of the present invention has an inner diameter sufficiently larger than the outer diameter of the communication wire and has the communication wire inserted in its hollow portion. And an outer pipe provided so as to cover the inner pipe and sandwiching a heat insulating material between the inner pipe and the inner pipe.

In such technical means, the inner diameter of the inner pipe being sufficiently larger than the outer diameter of the communication line means that when the communication line is inserted into the hollow portion of the inner pipe, a gap is generated between the two. is there. This gap functions as a play allowance for the communication cable inserted in the inner pipe. Therefore, the inner diameter of the inner pipe is required to be arbitrarily determined according to the outer diameter of the communication line to be inserted, but if the gap between the two is small, the communication line will be compressed when the communication cable is bent. This means that the effects of the present invention cannot be fully enjoyed, and if the gap between the two is too large, the communication cable unnecessarily becomes thick, which is not preferable. The difference between the inner diameter of the inner pipe and the outer diameter of the communication wire will differ depending on how much bending is required for the communication cable, but it can be said that about 0.3 mm is sufficient.

As the heat insulating material sandwiched between the inner pipe and the outer pipe, a substance having a low thermal conductivity may be appropriately selected. A kneaded product added with a binder by weight, that is, ceramics before firing, asbestos, and the like can be mentioned. Further, the thickness of the heat insulating material may be properly changed depending on the heat resistance required for the communication cable.

[0008]

According to such technical means, since the inner diameter of the inner pipe is sufficiently larger than the outer diameter of the communication line, a gap is formed between the communication line and the inner pipe, so that the heat insulating material is sandwiched. Even if the inner pipe and the outer pipe are bent, external force does not act on the communication line.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The heat resistant communication cable of the present invention will be described in detail below with reference to the accompanying drawings. 1 and 2 show a first embodiment of the heat resistant communication cable of the present invention. Sign
Reference numeral 1 denotes a communication line such as an optical fiber or a conductive wire, which is inserted in the hollow portion of the inner pipe 2 with a certain allowance. Here, the inner diameter of the inner pipe 2 is about 1.2 mm when the outer diameter of the communication line is 0.9 mm. Also,
Reference numeral 3 is a heat insulating material which covers the outer peripheral surface of the inner pipe 2 in layers, and is obtained by adding 10 to 25% by weight of a binder to fine ceramic powder such as magnesia and kneading the same. Reference numeral 4 denotes an outer pipe 4 that covers the heat insulating material 3 and is made of stainless steel such as SUS304 like the inner pipe 2.

As a concrete manufacturing method of this heat resistant communication cable, first, the kneaded heat insulating material 3 is extruded into a tube shape, and then the inner pipe 2 is inserted into the inner diameter of the tube heat insulating material 3, The tubular heat insulating material (3) is covered with an outer pipe (4) having an inner diameter slightly larger than the outer diameter of the tubular heat insulating material (3). Then, in this way, the diameter of the cable in which the inner pipe 2, the heat insulating material 3 and the outer pipe 4 are stacked in three layers is reduced by a die to sandwich the heat insulating material 3 between the inner pipe 2 and the outer pipe 4, and finally. Communication line 1 to inner pipe 2
The heat-resistant communication cable of this embodiment is completed by inserting it inside.

In the heat-resistant communication cable of this embodiment having the above-mentioned structure, the play allowance of the communication line 1 is ensured in the inner pipe 2, so that when the communication cable is bent by laying work or the like. However, the communication line 1 is not pressed by the heat insulating material unlike the conventional heat resistant communication cable. Therefore, in the heat-resistant communication cable of the present embodiment, it is not necessary to consider the transmission loss of the communication line 1 when performing bending processing on this, and there is an advantage that the flexibility of cable laying work is improved. is there.

Next, FIG. 3 shows a second embodiment of the heat resistant communication cable of the present invention. In this embodiment, a plurality of inner pipes 2 in which the communication lines 1 are inserted one by one are bundled, and the inner pipes 2 are connected to the heat insulating material 3 and the outer pipe 5.
Covered with. Therefore, even in the heat resistant communication cable of this embodiment, the communication line 1 in the inner pipe 2 is not pressed when it is bent, like the first embodiment,
The cable laying work can be performed without considering the transmission loss of the communication line 1.

[0013]

As described above, according to the heat resistant communication cable of the present invention, a gap is formed between the communication line and the inner pipe, and the inner pipe and the outer pipe sandwiching the heat insulating material are provided. External force does not act on the communication line even if it is bent, so even if this communication cable is bent by laying work etc., the transmission loss of the communication line does not increase, and the original function of the communication line Can be maintained more than enough.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of a heat resistant communication cable of the present invention.

FIG. 2 is a cross-sectional view of the heat resistant communication cable according to the first embodiment.

FIG. 3 is a perspective view showing a second embodiment of the heat resistant communication cable of the present invention.

FIG. 4 is a cross-sectional view showing a conventional heat resistant communication cable.

[Explanation of symbols]

 1 ... communication line, 2 ... inner pipe, 3 ... insulation material, 4 ... outer pipe

Claims (1)

[Claims] 1. An inner pipe having an inner diameter sufficiently larger than the outer diameter of the communication line and having the hollow portion into which the communication line is inserted, and an inner pipe provided so as to cover the inner pipe. A heat-resistant communication cable comprising an outer pipe sandwiching a heat insulating material.