JPH0287420A - Composite cable and laying method therefor - Google Patents

Abstract

PURPOSE:To form a complex cable consisting of an optical fiber and electric wires, which enables simple execution of cable laying works, by accommodating optical fiber and the electric wires partially folded in a sheath. CONSTITUTION:Electric wires 1, 2 and an optical fiber 3 are accommodated in a flexible tubular sheath 4 made of synthetic resin. If the electric wire 2 is used as a grounding wire while the one 1 as a power supply wire or signaling wire, the electric wire 1 is collapsed into specified lengths and accommodated, and the outer side-face of the sheath 4 is marked as specified in correspondence to these folded parts to provide possibility of judgement from outside the sheath 4 to know where the folded part exists. The sheath 4 is exfoliated partially at the folded part of the electric wire 1, and the surplus length folded in is pulled out. If for ex. a smoke sensor 5 is connected by the use of this surplus of approx. 1m long, laying of optical fiber 3 can be made simply and easily together with laying of the electric wire 1 while connections of the power line and signaling line with a number of smoke sensors 5 are being carried out.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a composite cable that accommodates a combination of electric wires and optical fibers, and a method for laying this composite cable.

[Conventional technology]

Conventionally, electric wires such as power lines and communication lines and optical fibers have generally been constructed as separate cables. For example, in order to detect temperature and smoke inside a tunnel, an optical fiber for the temperature sensor and an electric wire for supplying power to the smoke detector and transmitting the signal from it are laid in parallel. In some cases, it may be necessary to install ordinary electrical wire cables and optical fibers separately. Therefore, the installation work is complicated and time-consuming. Furthermore, since optical fibers are thin and fragile, they require reinforcement, which also makes the work complicated. For this reason, a composite cable that accommodates an electric wire and an optical fiber in one sheath is considered.

[Problem to be solved by the invention]

However, even when such a composite cable is used, as in the example above, in order to detect temperature and smoke inside the tunnel, optical fibers for temperature sensors must be laid inside the tunnel, and many smoke detectors must be installed. When installing a smoke detector, it is necessary to connect one of many smoke detectors in the middle of the electric wire, so it is necessary to cut this composite cable at each smoke detector installation point and lay it. The complexity of the task is not significantly improved. This invention allows for easy installation work, especially in cases where there are many points to be connected to electric wires along the way.
It is an object of the present invention to provide a composite cable of optical fiber and electric wire and a method for laying this composite cable.

[Means to solve the problem]

In order to achieve the above object, a composite cable according to the present invention is characterized by comprising a sheath, an optical fiber housed in the sheath, and a partially folded electric wire housed in the sheath. It becomes. Further, according to the composite cable installation method of the present invention, the sheath is peeled off at the folded portion of the composite cable to draw out the extra length of the electric wire, and the extra length is used to connect the electric wire to a predetermined electrical device. It is characterized by being connected to.

[Function] In this composite cable, the electric wires are partially folded and accommodated, so there is an extra length in the folded part. Therefore, by peeling off the sheath at this folded portion and pulling out the folded portion of the electric wire, this extra length can be utilized. Therefore, the electric wire can be connected to a predetermined electrical device using this extra length. Furthermore, since the optical fiber does not come out of the sheath during the connection of electrical equipment in the middle of the cable, there is no risk of the optical fiber breaking or bending, and the installation work can be done easily. .

【Example】

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a composite cable according to an embodiment of the present invention, and FIG. 2 is a vertical cross-sectional view of the same composite cable. As shown in these figures, the composite cable includes an electric wire 1.2 and an optical fiber 3 in one flexible tubular sheath 4 made of synthetic resin or the like.
It is composed of the following. In the case of this embodiment, when the electric wire 2 is used as a ground wire and the electric wire 1 is used as a power supply line or a signal line, the electric wire 1, which is the power supply line or signal line, is folded and housed at intervals of a certain length. . Although not shown in the figure, a predetermined mark or the like is attached to the outer surface of the sheath 4 corresponding to this folded portion, so that the location of the folded portion can be determined from the outside of the sheath 4. . This composite cable is laid as follows. In this embodiment, in order to perform temperature detection and smoke detection in a tunnel with a length of 2 km, optical fibers for temperature sensors are installed inside the tunnel, and a large number of smoke detectors are installed every 20 m. Therefore, folded sections were provided every 20 m, and a composite cable was formed in such a way that an extra length of 1 m was generated by folding the cable. At this time, as shown in FIG. 3, the sheath 4 is partially peeled off at the folded portion of the electric wire 1, and the extra length of the electric wire 1 produced by the folding is pulled out. The folding part is sheath 4
It can be easily recognized by the marks etc. on the outside surface. Then, using this extra length of about 1 m, the work of connecting the smoke detector 5 is performed at each folded portion. By laying this composite cable in this way, it is possible to simply and easily lay the optical fiber 3 and the electric wire 1 while connecting the power lines and signal lines to a large number of smoke detectors 5. Moreover, during this installation work, the optical fiber 3 is connected to the sheath 4.
Since the optical fiber 3 is not exposed to the outside, the optical fiber 3 is not bent or bent, and the work is easy in this respect as well. In this embodiment, since the optical fiber 3 is used as a temperature sensor, an optical fiber Braman (or Rayleigh) thermometer is connected to one end of the optical fiber 3. The Raman scattered light (or Rayleigh scattered light) is measured at each position, and the temperature distribution in the length direction of the optical fiber 3 is measured. By connecting a computer to this optical fiber thermometer, the temperature at specific points along the length of the optical fiber 3 can be displayed in degrees Celsius on the computer's display screen, for example. be able to. In this example, the temperature distribution along the composite cable is measured, and smoke detection is performed at points along the composite cable, so it is possible to reliably detect the occurrence of a fire using both smoke detection and temperature rise. can. In addition, although the case where the electric wire for a smoke detector and the optical fiber for a temperature sensor were combined was demonstrated above, it is needless to say that it is not limited to this. It is possible to connect not only smoke detectors but also desired electrical equipment such as emergency lights and fire alarms that require connection of electric wires as power supply lines or signal lines. Furthermore, optical fibers can be used not only for temperature sensors but also for optical signal transmission.

【Effect of the invention】

According to the composite cable and its installation method of the present invention, the electric wire and the optical fiber can be connected while connecting a desired electric device to the electric wire in the middle of the cable without fear of the optical fiber being bent or increasing loss due to bending. Easy to install with simple work.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a composite cable according to an embodiment of the present invention, Fig. 2 is a longitudinal sectional view of the same composite cable, and Fig. 3 is a diagram showing the case where this composite cable is laid while connecting a smoke detector. It is a schematic diagram. 1.2...Electric wire, 3...Optical fiber, 4...Sheath, 5...Smoke detector.

Claims (2)

[Claims] (1) A composite cable comprising a sheath, an optical fiber housed in the sheath, and a partially folded electric wire housed in the sheath. (2) The sheath is peeled off at the folded portion of the composite cable according to claim 1, the extra length of the electric wire is drawn out, and the extra length is used to connect the electric wire to a predetermined electrical device. How to lay composite cables.