JPH02231550A - Water infiltration sensor instrument - Google Patents

Abstract

PURPOSE:To rapidly and exactly detect water infiltration by providing the water infiltration sensor instrument which is provided with a water absorptive expansion material in alignment to the axial direction of a casing and is constituted to apply a pressing force to coated optical fibers and to curve the fibers when swollen by absorbing water, in the bottom of the cylindrical closer of an optical fiber cable. CONSTITUTION:The water infiltration sensor instrument 8 is constituted of a chamber block 22 provided with the water absorptive expansion material 31, the box-shaped casing 20 consisting of a solid part block and by passing the coated optical fibers 5, 5a in the casing and putting a cap 20a thereon. This instrument is disposed in the bottom of the cylindrical closure 6 which is the juncture of the optical fiber cables 1, 1a. Water passes the through-hole on the base of the casing 20 and is absorbed in the water absorptive expansion material 26 when the water infilters the enclosure 6. The expansion material 26 is rapidly expanded in this way to push a fixing plate 32 up to a stopper 33 via the position of a chain line A. The coated fibers 5, 5a curve like a chain line B in a recessed part 29 in a central groove 28 to increase the transmission loss of light. This increase is detected and the water infiltration is known.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a water immersion sensor device used to detect water intrusion into a cylindrical closure housing a connecting portion of an optical fiber cable.

[Conventional technology]

Conventional communication networks use copper cables, and if the copper wires in the copper cables get wet, communication will be disrupted.
An important issue was to prevent the outer surface of the copper wire cable from being damaged and the internal copper wires from flooding. To prevent the above-mentioned flooding, a measure called the so-called "gas maintenance method" has usually been taken. This is a situation in which a gas is always sealed inside the cable and kept at a constant pressure, and when the gas leaks out of the cable, the above pressure decreases, causing damage to the cable (and eventually water intrusion into the cable). The purpose is to detect.

However, recently, optical fiber cables have been used instead of the copper wire cables mentioned above, and since the optical fiber core wires used for communication in these optical fiber cables are sufficiently protected, water intrusion etc. can only be detected at the connection part. It is now sufficient to carry out maintenance and management.

[Problem that the invention seeks to solve]

This type of fiber optic cable connection generally uses a cylindrical closure, with one end of the fiber optic cable introduced into the closure from one end face, and the end of the other fiber optic cable introduced from the other end face. Optical fibers pulled out from both ends are connected with their ends butted against each other. It is not appropriate to use the conventional gas maintenance method for the connection portion of an optical fiber cable having such a structure because of problems such as structural problems and management costs.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide a water immersion sensor device that is easy to maintain, has a long life, and can be miniaturized.

[Means for solving problems]

In order to achieve the above object, the water immersion sensor device of the present invention is disposed on the bottom part of a cylindrical closure coaxially accommodating a connecting part connecting the ends of one and the other optical fiber cable, and and the odor of a water immersion sensor that coaxially accommodates any of the plurality of optical fiber core wires pulled out and connected from the end of the other optical fiber cable so as to come into contact with infiltrated water, and at least the bottom side absorbs water. A box-shaped casing formed in the casing, optical fiber outlet ports formed facing each other on both end faces perpendicular to the axial direction of the casing, and an optical fiber outlet that is housed in the box-shaped casing with the axial directions aligned. a water-absorbing expandable material, one end of which is in contact with one end of the casing, and the other end is a free end facing the other end of the casing with a space therebetween; and the other end of the casing and the water-absorbing expandable material. A part of the stop flange provided between the free end of the box-shaped casing and a part corresponding to the free end of the optical fiber core wire crossing inside the box-shaped casing are fixed to the free end, and a part corresponding to the other end of the casing. It has a structure in which a fixing device is provided for fixing it to the other end.

[Effect]

The present inventors focused on the characteristic of optical fibers that the amount of light passing through the optical fiber changes when the optical fiber is physically bent. The idea was that the above water intrusion could be detected quickly and accurately by converting it into a bending force. Then, as the material used for the above conversion, a water-absorbing and expanding material that absorbs and expands in water is used, and
The inventors have discovered that by devising the attachment, etc., it is possible to obtain a water immersion sensor device that is highly reliable, has a long life, and can be miniaturized, and has thus arrived at this invention.

Next, the present invention will be explained based on examples.

〔Example〕

FIG. 1 shows the installation state of a water immersion sensor device according to an embodiment of the present invention. In these figures, 1 and 1a are a pair of left and right optical fiber cables, 2 and 2a are cable grips that fix and hold the ends of the optical fiber cable 11a, and 3 and 3a are the ends of the optical fiber cable 1.1a, respectively. The tension members 4, 4a pulled out from the holder are tension member gripping parts that fix and hold the tension members 3, 3a. Also, 5
, 5a are a plurality of optical fiber cores drawn out from the end of the optical fiber cable 1.1a,
The end surfaces of this optical fiber core wire 55a are butted against each other. Reference numeral 10 denotes a connecting portion housing portion (excess length processing portion), and 6 denotes a cylindrical closure that accommodates these in a watertight state. Further, 7 is an end plate that closes both ends of the closure 6. The water immersion sensor device 8 of the present invention is attached to the connecting portion housing portion 10 of the optical fiber core wires 5, 5a at the lowest stage, which are not used for optical communication. As shown in FIG. 2 and FIG.
The casing 20 is provided with a lid body 20a having a through-hole on the upper surface and removably covering the casing 20 by engaging the first claw portion with the recessed portions at the four corners of the casing 20. The rectangular box-shaped casing 20 has a chamber block 22 on the left side from the center in the longitudinal direction, and a solid block 23 on the right side. As shown in FIG. 3, inside the chamber block 22 on the left side of the box-shaped casing 20, a central protrusion 25 with a first central groove 24 extends from one longitudinal end to the other end. The interior of the chamber block 22 of the casing is divided into two chambers 26.2 on the left and right by the protrusion 25.
It is divided into 7 parts. Further, the first central groove 2 of the central protrusion 25 is provided in the solid block 23 of the casing 20.
4 is extended, the second central groove 28 is connected to the casing 20.
It is formed up to the end. In this case, one of the groove walls of the second central groove 28 is hollowed out in a thick arch shape as shown in the figure, and that portion is formed into a large recess 29. At the entrance side portion of the second central groove 28, opposing groove walls are hollowed out so that the entire entrance is formed into an arch-shaped groove guide portion 30. Further, the outlet side portion of the second central groove 28 is formed into a rectangular fixture housing chamber 31a. Two left and right chambers 2 separated and formed by the central protrusion 25
6.27, water-absorbing and expanding materials 31 each having a shape that fits within the two chambers 26.27 are disposed. These water-absorbing and expanding materials 31 are made of ethylene-propylene-diene rubber (EPD).
It is composed of a water-absorbing and expanding rubber containing M) as a main component and having a water-swelling agent and a water-absorbing agent dispersed throughout.

Reference numeral 32 denotes a fixing plate which is formed into a substantially U-shape. Both horizontal sides of the U-shape are aligned with the outer surfaces of both the left and right water-absorbing and inflatable materials 31, and the vertical sides of the U-shape are aligned with the outer surfaces of both the water-absorbing and inflatable materials 31. The chamber block 22 is placed along the front end surface and the front end surface of the central protrusion 25.
located within. In this chamber block 22, the space between the boundary wall between the solid block 23 and the chamber block 22 and the U-shaped vertical side of the U-shaped fixing plate 32 is created by the water absorption and expansion of the water absorption and expansion material 31. This provides a movement space when the fixing plate 32 moves to the right in the drawing due to the pressing force. and,
Boundary wall 3 between the solid block 23 and the chamber block 22
3 serves as a stopper portion for the movement of the fixed plate 32.

Reference numeral 34 denotes a first fixing metal fitting, which is disposed in the first and second central grooves 24.28 and is inserted across the casing 20 at the front end of the water absorbing and expanding material 31 in the optical fiber cores 5, 5a. Optical fiber core 5 corresponding to the surface,
The portion 5a is fixed to the front end surface of the water-absorbing and expanding material 31 via the fixing plate 32. Reference numeral 35 denotes a second fixture for fixing a portion of the optical fiber cores 5, 5a corresponding to the fixture housing chamber 31a of the solid block 23 to a corner of the inner wall surface of the fixture housing chamber 31. Note that 36 is a cutout hole provided in the fixing plate 32 for passing the optical fiber core wires 5, 5a, and 37 is a protrusion that fits into the upper part of the fixture storage chamber 31a to close the lid.

In this configuration, the optical fiber core wires 5, 5a are connected to the first and second parts of the casing 20, as shown in FIG.
It is positioned within the second central groove 24, 28 and fixed at a predetermined portion thereof by first and second fixing devices 34, 35. In this case, the inlet portion 30 of the second central groove 28
Since the area is wide, installation work is easy.

Next, the box-shaped casing 20 through which the optical fiber core 5.5a is passed is covered with a lid 20a to constitute a water intrusion sensor device, and the casing is closed in the longitudinal direction.
It is arranged at the bottom of the closure 6 in a state aligned with the axial direction of the closure 6 as shown in FIG. In this state, if water floods into the closure 6, the water will flow through the box-shaped casing 2.
Water is absorbed into the water-absorbing and expanding material 26 through the through holes in the bottom surface of the container.

In this case, the rectangular box-shaped casing 20 is arranged with its short side force direction aligned with the circumferential direction of the cylindrical closure 6, and the bottom surface of the casing 20 is aligned with the bottom surface of the cylindrical closure 6. It's getting closer.

Therefore, it is advantageous for early detection of flooding. As the water absorption and expansion material 31 absorbs water, the water absorption and expansion material 31 rapidly swells and pushes the fixing plate 32 from the solid line position in FIG. In this case, the optical fiber core wires 5, 5a, which were in a straight state, are bent as shown by the chain line B in the recess 29 of the second central groove 28, thereby increasing the transmission loss of light. Therefore, by detecting this, it becomes possible to quickly and accurately determine whether water has entered the closure 6.

In this case, the bending of the optical fiber core wires 5, 5a is regulated by the action of the stopper part 33 at a stage before permanent deformation occurs, and the bending is made along the arch shape of the four parts 29, so that the bending is performed within the closure 6. When the water subsides and returns to normal, the optical fiber core wires 5, 5a recover to their initial shapes and do not cause any problems.

FIG. 4 shows another embodiment. That is, this water immersion sensor device substantially corresponds to the first and second grooves 24. of the water immersion sensor device of FIGS. 2 and 3.
28 constitutes a casing 40, and a water-absorbing and expanding material 31 is disposed in 24 corresponding to the first central groove, and its water-absorbing expansion moves the fixing plate 32 to the position C shown by the chain line in the figure. 5.5a is bent as shown by the chain line D from the solid line state. 3435 is a first and second fixture, and 33 is a stopper piece. This embodiment has the same effects as the above embodiment, and also
Furthermore, there is an effect that the entire structure can be simplified.

In addition, in the above embodiment, the fixed plate 32 and the water-absorbing expansion material 31
Although these are separate bodies, they may be integrated, for example by making the front surface of the water-absorbing and expanding material 3l a push plate part. Further, the lid 22 of the box-shaped casing 20 may be removed depending on the case.

Furthermore, the entire box-shaped casing 20 may be made of a porous material made of a porous water-absorbing resin whose main component is polyethylene or phenol resin. In this case, there is no need to provide a through hole in the bottom surface of the casing 20.

As described above, in the present invention, the box-shaped casing in which at least the bottom surface side is formed as a water absorption part includes a box-shaped casing made of a non-porous material with through holes formed in the bottom surface, and a box-shaped casing made of a non-porous material with a through hole formed in the bottom surface, and a box-shaped casing made of a non-porous material with a through hole formed in the bottom surface. Includes items made of materials.

〔Effect of the invention〕

Since the water immersion sensor device of the present invention is configured as described above, it is possible to quickly and accurately detect water immersion within the cylindrical closure, and maintenance management at this time is extremely simple.

In particular, this water immersion sensor device has water-absorbing and expanding materials disposed in the casing aligned in the axial direction, and causing the water-absorbing and expanding materials to absorb water and swell in the axial direction of the casing, thereby axially moving the optical fiber core. Since the casing is bent by applying a pressing force of , the width of the casing in the direction perpendicular to the axis (width direction) can be set small. In other words, in this water immersion sensor device, the swelling direction of the water-absorbing and expanding material is set in the axial direction of the casing.
Although the casing requires a considerable length in the axial direction, the length in the direction perpendicular to the axis (width direction) can be shortened. Therefore, when housing the water immersion sensor device of the present invention in a cylindrical closure, by accommodating the casing with its width direction (short length) aligned with the circumferential direction inside the closure, the bottom surface of the casing can be placed inside the closure. This makes it possible to quickly detect water intrusion into the cylindrical closure. Furthermore, since the water immersion sensor device of the present invention is provided with a stopper portion that appropriately restricts the bending of the optical fiber, the optical fiber is not bent in a manner that would cause permanent distortion. Therefore, it can be used repeatedly and has a long lifespan.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view showing an installed state of an embodiment of the present invention, Fig. 2 is a plan view of the water immersion sensor with the lid removed, Fig. 3 is an exploded perspective view thereof, and Fig. 4 is FIG. 7 is a plan view of another embodiment. 1, 1a... Optical fiber cable 5, 5a...
Optical fiber core 6... Cylindrical closure 8...
・Water immersion sensor tool 20...Box-shaped casing 31・
・・Water absorption and expansion material 32 ・・Fixing plate 33 ・・Stopper parts 34, 35 ・・Fixing metal fittings

Claims (1)

[Claims] (1) Disposed on the bottom of a cylindrical closure that coaxially accommodates a connection part that connects the ends of one and the other optical fiber cables, and is pulled out and connected from the ends of the one and other optical fiber cables. A water immersion sensor device coaxially accommodates any one of a plurality of optical fiber cores so as to be in contact with infiltrating water, the box-shaped casing having at least a bottom surface formed as a water absorption part; optical fiber outlet openings formed opposite to each other on both end faces orthogonal to the axial direction of the optical fiber core, and an optical fiber outlet port that is housed in the box-shaped casing with the axial directions aligned, and one end in the axial direction abuts one end portion of the casing; a water-absorbing expandable material whose other end is a free end facing the other end of the casing with a space therebetween; a stopper portion provided between the other end of the casing and the free end of the water-absorbing expandable material; , comprising a fixture for fixing a portion corresponding to the free end of the optical fiber core crossing inside the box-shaped casing to the free end, and fixing a portion corresponding to the other end of the casing to the other end. A water immersion sensor device characterized by: