JPH07134227A - Optical fiber cable with temperature sensor - Google Patents

Abstract

PURPOSE:To enable the exact detection to be carried out by directly detecting the disconnection of coated optical fibers and peeling of clads from a temp. rise at an accident point by using a temp. sensor wire arranged in the optical fiber cable. CONSTITUTION:This optical fiber cable consists of at least >=1 pieces of the coated optical fibers 1, the temp. sensor wire 2 longitudinally applied on these coated optical fiber 1 or spirally wound around these fibers and a protective layer 3 covering the respective outer peripheries thereof. If the accident, such as disconnection or clad peeling, arises at the coated optical fibers 1, the light leaking from this place is absorbed in an optical fiber cable constituting material having the higher light absorbance as compared with the cores and heat is generated. The temp. rise near the accident point by the heat is detected by the temp. sensor wire 2. Then, the heat generated at the accident point in the event of the generation of the accident, such as disconnection of the coated optical fibers 1 or peeling of the clad layers, is detected by the temp. sensor wire 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber cable with a temperature sensor.

[0002]

2. Description of the Related Art Conventionally, the disconnection detection of an optical fiber cable for energy transmission which transmits high-density visible light is not performed by the optical fiber cable itself, but an indirect external device such as monitoring the emitted light by a photo sensor. It was done by detection means. In this case, there is a problem in that it is difficult to distinguish the emitted light variation due to the transmission loss variation of the optical fiber cable due to the variation of the light amount of the light source, the temperature variation and the mechanical deformation from the emitted light variation due to the disconnection. Also, a means for cleaving a part of the emitted light to the photo sensor is required on the emitting end side,
There are problems that the emitted light that can be used is reduced and that the device configuration on the emission side becomes complicated. In addition, the optical fiber cable application device as a whole is required to have a safety interlocking protection mechanism that shuts off the incidence of light on the incident side of the optical fiber cable when an accident is detected. There is a problem that a wiring for transmitting to the incident side is required.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned problems of the prior art.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and at least one optical fiber core wire is vertically attached to the core wire or spirally wound around the core wire. An optical fiber cable comprising a temperature sensor wire and a protective layer coated on the outer circumference thereof.

In the optical fiber cable of the present invention,
When an accident such as disconnection of the optical fiber core or peeling of the cladding layer occurs, heat generation at the accident location can be detected by the temperature sensor wire.

FIG. 1 is a principle view of an optical fiber cable with a temperature sensor according to the present invention. As shown in the figure, it comprises at least one optical fiber core wire 1, a temperature sensor wire 2 which is vertically attached to or spirally wound around the optical fiber core wire 1, and a protective layer 3 which covers the outer circumference thereof. When an accident such as disconnection or clad separation occurs in the optical fiber core wire 1, light leaking from that location is absorbed by the optical fiber cable constituent material having a higher light absorption rate than the core, and heat is generated. The temperature sensor wire 2 detects the temperature rise near the accident location due to the heat. FIG. 2 shows an example of the structure of a temperature sensor wire that is preferably used in an optical fiber cable with a temperature sensor. In the figure, 4 is the central thread,
Reference numeral 5 is a primary conductor, 6 is a temperature sensitive layer, 7 is a secondary conductor, 8 is a covering layer, and 9 is a sheath. As shown in the figure, the temperature sensor wire is composed of two conductors 5 and 7, and a temperature-sensitive layer 6 and other members having temperature characteristics such that the resistance sandwiched between them is monotonically decreased when the temperature rises. Is preferred. In the case of such a structure, the resistance at each place in the longitudinal direction of the wire is equivalent to a circuit in which the two conductors are connected in parallel between the two conductors, so that a local temperature rise occurs due to an accident at only one place. This is because the resistance changes greatly when viewed from the ends of the two conductors. Examples of temperature sensor wires having such characteristics include temperature sensor wires for electric blankets and electric carpets, which are also applicable to the present invention.

[0007]

[Example] PC having a core diameter of 0.8 mm as an optical fiber
An S optical fiber consisting of 9 cores and a temperature sensor wire with a diameter of 2 mm, which uses a plastic thermistor as a temperature sensitive layer material, is bundled, and the outer circumference thereof is covered with PVC as a protective layer.
An optical fiber cable of m was prototyped. When left at room temperature of about 20 ° C., the resistance between the two conductors of the temperature sensor wire was 800 kΩ. When a part of this optical fiber cable was immersed in water at 60 ° C for about 100 mm, the resistance became 30 kΩ. When the same optical fiber cable was taken out of water at 60 ° C. and left at room temperature of about 20 ° C., the resistance returned to 800 kΩ before immersion. Next, with the visible light of about 2.5 W incident on each of the PCS optical fiber cores, 9 P
When one of the CS optical fiber core wires was intentionally broken and left to stand, the resistance rapidly dropped from 800 kΩ to about 200 Ω. However, at this time, the temperature sensor wire 2
The resistance between the conductors of the book did not recover above about 1 kΩ.

[0008]

According to the present invention, the temperature sensor wire arranged inside the optical fiber cable is used to directly detect the disconnection of the optical fiber core wire and the peeling of the clad by the temperature rise at the accident location. Accurate detection can be performed, and by concentrating the accident detection and its processing means on the light source side, it is possible to simplify the overall configuration of the apparatus using the optical fiber cable for energy transmission.

[Brief description of drawings]

FIG. 1 is a sectional perspective view of an optical fiber cable with a temperature sensor.

FIG. 2 is a cross-sectional perspective view of a temperature sensor wire.

[Explanation of symbols]

 1: Optical fiber core wire 2: Temperature sensor wire 3: Protective layer 4: Central yarn 5: Primary conductor 6: Temperature sensitive layer 7: Secondary conductor 8: Encapsulation layer 9: Sheath

Claims (1)

[Claims] 1. A temperature sensor wire which is at least one optical fiber core wire, which is vertically attached to the core wire or spirally wound around the core wire, and a protective layer which is coated on the outer circumference thereof. And optical fiber cable.