JPH02227632A - Water immersion sensor tool - Google Patents

Abstract

PURPOSE:To accurately and speedily detect water immersion by providing a couple of water-absorptive expansion materials with curved parts facing each other across coated optical fibers on the internal floor surface of a box type casing made of a porous material. CONSTITUTION:The coated optical fibers 5 and 5a are arranged as shown by a chain line A while arranged between a couple of pressure plates 24 and 25 whose coupling parts are combined with a water-absorptive expansion materials 26. Then the box type casing 20 that the coated optical fibers 5 and 5a penetrate is covered with a lid to constitute the water immersion sensor tool, which is arranged on the bottom part of a closure 6. In this state, if water enters the closure 6, the water passes through pores of the casing 20 and is speedily absorbed by the porous bottom plate 23 and absorbed by the swelling parts 26. The expansion materials 26 speedily expand by the water absorption to narrow down the gap between both the pressure plates 24 and 25, so the coated optical fibers 5 and 5a which are straight when not impregnated with water bend as shown by a chain line B, so that the transmission loss of light increases. For the purpose, this is detected to speedily and accurately grasp the water immersion in the closure 6.

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 certain amount of gas is always sealed inside the cable and maintained at a certain 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, there is no risk of water intrusion at the connection part. Detection and maintenance management is now sufficient.

[Problem that the invention seeks to solve]

This type of optical fiber cable connection generally uses a cylindrical closure, in which one end of the optical fiber cable is introduced into the closure from one end face, and the other end of the optical fiber cable is introduced from the other end face. Optical fiber cores drawn 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 intrusion sensor device that is easy to maintain and manage and can quickly detect water intrusion at a connecting portion.

[Means for solving problems]

In order to achieve the above object, the water immersion sensor device of the present invention is disposed in the bottom part of a cylindrical closure that coaxially accommodates a connecting part connecting the ends of one and the other optical fiber cable, and A water immersion sensor device for coaxially accommodating any one of a plurality of optical fiber cores pulled out and connected from the end of an optical fiber cable so as to come into contact with infiltrating water, the bottom surface of which is the cylindrical closure described above. A box-shaped casing made of a porous material, which is formed into a curved surface that follows the curved surface of the bottom surface of the casing, and whose internal floor surface is flat, and an optical fiber core formed in opposing state on both end surfaces perpendicular to the axial direction of the casing. The apparatus is configured to include a drawing outlet and a pair of water-absorbing and expanding materials with curved surfaces facing each other on the inner floor surface of the box-shaped casing with the optical fiber core interposed therebetween.

[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 water and expands is used, and
This invention was achieved by discovering that a highly reliable water immersion sensor tool could be obtained by devising the mounting tools.

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

〔Example〕

FIGS. 1 and 2 show how a water immersion sensor device according to an embodiment of the present invention is installed. In these figures,
1. la is a pair of left and right optical fiber cables, 2.2a
3.3a are tension members drawn out from the ends of the optical fiber cable 1.1a, and 4 and 4a are the tension members 3. .3a is a tension member gripping part that fixes and holds it. Further, 5.58 is a plurality of optical fiber cores drawn out long from the end of the optical fiber cable, and the end surfaces of the optical fiber cores 5.5a are butted against each other and connected, and 10 is a coating and sealing portion thereof; 6 is a cylindrical closure that accommodates these. Further, 7 is an end plate that closes both ends of the closure 6. And the lowest optical fiber core 5 which is not used for optical communication.
．． A water immersion sensor device 8 is attached to the cover sealing portion 10 of 5a. As shown in FIGS. 3 to 6, this water immersion sensor device includes a box-shaped casing 20 whose bottom surface is formed into a curved surface that follows the curved surface of the bottom surface of the cylindrical closure 6, and claw portions of four legs 21. A lid body that removably covers the casing 20 by engaging with the recessed portion of the casing 20 is provided. The casing 20 is made of a porous material made of a porous water-absorbing resin whose main component is polyethylene or phenol resin, and a porous upper base plate 23 made of the same material is housed inside the casing 20. 23 has a bottom surface formed into a curved surface along the bottom surface of the casing 20, and a top surface formed into a flat surface. A push plate 24 having a protrusion and a push plate 25 having a recess are disposed on the upper surface of the porous upper base plate 23, facing each other with the optical fiber core indicated by the chain line A sandwiched therebetween. Between these push plates 24, 25 and the wall surface of the box-shaped casing 20, there is a rubber material made of water-absorbing and expanding rubber, which is mainly composed of ethylene-propylene-diene rubber (EPDM) and has a water-swelling agent and a water-absorbing agent dispersed throughout. A water-absorbing expansion material 26 is provided. 27 is
These are outlet ports that are formed facing each other on both end faces perpendicular to the axial direction of the box-shaped casing 20, and allow the optical fiber core 5.5a to pass across the inside of the casing 20 (dashed line A).

In this configuration, the optical fiber core 5.5a is connected to the water-absorbing expansion material 2 as shown in FIGS. 5 and 6.
6 and is arranged between a pair of push plates 24 and 25 combined with each other as shown in the chain line. Next, in the box-shaped casing 20 through which the optical fiber core wires 5 and 5a are passed,
The lid 22 is covered to constitute a water immersion sensor device, which is disposed at the bottom of the closure 6. In this state, if water floods into the closure 6, the water will flow through the box-shaped casing 2.
Water is quickly absorbed into the porous upper base plate 23 through the pores of
This water-absorbing and expanding material 2 is then absorbed by the water-absorbing and expanding material 26.
Due to water absorption in 6, the water-absorbing and expanding material 26 rapidly swells and the distance between the push plates 24 and 25 narrows, so that the optical fiber cores 5 and 5a, which were straight in the non-water immersion state, are bent as shown by the chain line B. This increases 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 the above embodiment, the push plate 24, 25 and the water-absorbing expansion material 26 are separate bodies, but they may be integrated, such as by forming a push plate part on the front surface of the water-absorbing expansion material 26. , as shown in FIG. 7, the porous upper base plate and the box-shaped casing may be integrated. Furthermore, the lid of the box-shaped casing may be removed depending on the situation.

〔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 a cylindrical closure. In particular, this water immersion sensor device has a box-shaped casing made of a highly water-absorbing porous material, the bottom of which is curved to follow the bottom of the cylindrical closure, and a water-absorbing movable material is placed on the internal floor of the casing. Since the mutual spacing is set so that it can be changed depending on the water absorption state, if even a small amount of water enters the bottom of the cylindrical closure, the infiltrated water will be absorbed by the bottom of the box-shaped casing formed along the bottom of the cylindrical closure. The water reaches the movable material through the porous upper base plate. Therefore, it becomes possible to quickly detect water intrusion into the cylindrical closure.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view showing an installed state of an embodiment of the present invention, Fig. 2 is a cross-sectional view taken along the line c-c', Fig. 3 is a perspective view of the water immersion sensor, and Fig. 4 is an exploded perspective view thereof. , FIG. 5 and FIG. 6 are explanatory views of operating states, and FIG. 7 is an exploded perspective view of essential parts of another embodiment of the present invention. 1.1a...Optical fiber cable 5.5a...
Optical fiber core 6...Cylindrical closure 8.
... Water immersion sensor tool 20 ... Box-shaped casing 23
...Porous upper bottom plate 24.25...Press plate 26...
・Water-absorbing expansion material 27... Outlet patent applicant Tokai Rubber Industries Co., Ltd.

Claims (1)

[Claims] (1) A plurality of fiber optic cables disposed on the bottom surface of a cylindrical closure that coaxially accommodates the connecting parts that connect the ends of one and the other optical fiber cables, pulled out from the ends of both optical fiber cables, and connected. A water immersion sensor device coaxially accommodates any one of the optical fiber cores in such a manner that it comes into contact with infiltrating water, the bottom surface of which is formed into a curved surface that follows the curved surface of the bottom surface of the cylindrical closure, and has an internal floor. A box-shaped casing made of a porous material and having a flat surface; an optical fiber outlet formed opposite to each other on both end faces perpendicular to the axial direction of the casing; and an internal floor surface of the box-shaped casing. A water immersion sensor device comprising a pair of water-absorbing and expanding materials with curved surfaces facing each other with an optical fiber sandwiched therebetween.