JP5186293B2 - Inundation sensor and detection device - Google Patents

Description

The present invention relates to a submersion sensor and a detection device that detect submersion in a closure for branch connection of an optical cable using an optical fiber.

Conventionally, as this type of water immersion sensor, there is a sensor that generates a transmission loss that can be detected by an optical pulse tester by applying bending and lateral pressure to an optical fiber when the water is flooded (Patent Documents 1 to 4). reference).
Japanese Patent Laid-Open No. 2002-22773 JP 2000-258225 A JP 2001-99756 A Japanese Patent Laid-Open No. 2001-262583

However, when a plurality of submersion sensors are provided in series along the optical fiber for detection, if one of them is submerged, transmission loss increases there. There has been a problem that the inundation sensor (at the far end side) cannot detect inundation or the detection performance deteriorates.
In order to suppress the side pressure that causes excessive transmission loss, it is conceivable to form a protective cover on the outer periphery of the optical fiber. In this case, it takes time to install the water immersion sensor because of the formation of the protective cover.
The present invention has been made in view of the above circumstances, and even when water is detected in one of a plurality of water immersion sensors provided in series with a single optical fiber for detection, the other side of the far end is also provided. It is an object of the present invention to provide a submersion sensor and a detection device that do not adversely affect the detection performance of the submersion sensor and are easy to install.

The present invention relates to a submersion sensor installed at intervals in the length direction of the detection optical fiber at a plurality of locations of the detection optical fiber, the container into which the detection optical fiber is drawn, and the storage A swollen material provided in the body, and a movable piece that is displaced by swelling of the swollen material due to water immersion in the housing body and bends the optical fiber for detection. A guide portion that guides the displacement of the movable piece in a direction in which bending is applied to the optical fiber, and a stopper portion that restricts the displacement of the movable piece along the guide portion are formed. Displacement can be restricted at a maximum displacement position and a bend applying position that can suppress a lateral pressure applied to the detection optical fiber, and the movable piece is engaged with the container at the bend applying position. Stop Providing flood sensors having a locking portion for keeping the bending state of the immersion sensing optical fiber Te.
In the submersion sensor of the present invention, the guide part is a slit-like hole or groove formed in the container, and the movable piece has a guide protrusion inserted into the guide part. Can be displaced in the bending application direction by moving along the guide part, and the stopper part regulates the displacement of the movable piece by the guide projection coming into contact with the predetermined bending application position. It is good as composition.
In the submerged sensor according to the present invention, the movable piece is formed with a posture maintaining portion that is a groove or a ridge along the displacement direction, and the container is provided with a ridge or groove having a shape conforming to the posture maintaining portion. A certain engaging part is good also as a structure formed so that engagement to the said attitude | position maintenance part is possible.
In the submerged sensor according to the present invention, the container includes a main portion having an upper opening and a lid portion that closes the upper opening, and the movable piece bends a convexity that imparts a bend to the optical fiber for detection. The lid portion has a receiving concave portion having a shape corresponding to the bending imparting convex portion of the movable piece, and the receiving concave portion bends the detection optical fiber between the bending imparting convex portion. It is good also as a structure which can be provided.
The stopper portion may be configured to be formed on the lid portion.
In the present invention, the water immersion sensor is installed at a plurality of positions of the detection optical fiber at intervals in the length direction of the detection optical fiber, and the detection optical fiber is located behind the detection optical fiber. A detection device connected to an optical pulse tester for detecting scattered light is provided.

According to the present invention, since the stopper is formed in the container to restrict the displacement of the movable piece, the maximum displacement position of the movable piece can be detected by the detection optical fiber without giving excessive bending loss. It can be set as the position which gives bending.
Since excessive loss does not occur in the detection optical fiber, even when one of the plurality of water immersion sensors provided in series with the detection optical fiber detects water immersion, the detection performance of the other water immersion sensors is adversely affected. Can be prevented.
In addition, since the water immersion sensor of the present invention can suppress the bending loss of the water optical fiber for detection of water immersion, it is not necessary to form a protective cover for suppressing the side pressure on the optical fiber for water detection, and is easy to install.

  A water immersion sensor 1 according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a front view showing the submerged sensor 1 in a state where the detection optical fiber 2 is not bent. FIG. 2 is a front view showing the water immersion sensor 1 in a state where the detection optical fiber 2 is bent. FIG. 3 is a perspective view showing the water immersion sensor 1. FIG. 4 is an exploded perspective view showing the water immersion sensor 1. FIG. 5 is a perspective view showing the lid 12.

  In FIG. 1, the water immersion sensor 1 includes a housing 3 into which the detection optical fiber 2 is drawn, a swelling material 4 provided in the housing 3, and swelling of the swelling material 4 due to water immersion in the housing 3. A movable piece 5 that is displaced to bend the optical fiber 2 for detection.

As shown in FIGS. 1, 3, and 4, the container 3 includes a substantially rectangular parallelepiped main portion 11 having an upper opening 11 a and a lid portion 12 that closes the upper opening 11 a.
The main part 11 is erected from a rectangular bottom plate part 13, side wall parts 14 and 14 erected from the long side parts 13 a and 13 a of the bottom plate part 13, and short side parts 13 b and 13 b of the bottom plate part 13. And end wall portions 15 and 15.

  When the side wall 14 is formed in a substantially rectangular shape, the guide part 17 that guides the displacement of the movable piece 5, the engaging part 18 that is a protrusion for maintaining the posture of the movable piece 5, and when the water is flooded An inflow hole 19 through which water flows into the container 3 is formed.

The guide portion 17 can be a slit-shaped hole portion formed along a direction (vertical direction in FIG. 1) from the bottom plate portion 13 toward the upper opening 11a. It is preferable that the guide portion 17 has a substantially constant width.
In the illustrated example, the guide portion 17 is formed from the upper edge of the side wall portion 14 to an intermediate position in the height direction. Two guide portions 17 in the illustrated example are formed at intervals in the length direction of the main portion 11 (longitudinal direction of the bottom plate portion 13, hereinafter simply referred to as the length direction).
The guide portion 17 may be any shape as long as it can guide the displacement of the movable piece 5 in the vertical direction, and is not limited to the shape illustrated, and may be a groove portion formed on the inner surface of the side wall portion 14, for example. .

The engaging portion 18 is a protrusion formed on the inner surface of the side wall portion 14 along the vertical direction in FIG. The engaging portion 18 in the illustrated example is formed at the approximate center in the length direction at the upper portion of the side wall portion 14.
The inflow hole 19 only needs to allow water to flow into the container 3. The inflow holes 19 in the illustrated example are formed in a slit shape along the vertical direction, and a plurality (four in the illustrated example) are formed at intervals in the length direction.

As shown in FIG. 4, the main part 11 of this example is assembled by detachably combining a first part 21 and a second part 22.
In the illustrated example, the first portion 21 is formed by integrating the one side wall portion 14, the one end wall portion 15, and the bottom plate portion 13, and the second portion 22 is the other side wall portion 14 and the other end wall portion. 15 is united.
A fitting piece 29 is formed at the end of the first portion 21 in the length direction of the side wall portion 14 so as to be detachably fitted in a fitting recess 28 formed in the end wall portion 15 of the second portion 22. A fitting piece 29 is removably fitted to a fitting recess 28 formed in the end wall portion 15 of the first portion 21 at the end portion in the length direction of the side wall portion 14 of the second portion 22. Is formed. The first portion 21 and the second portion 22 are detachably fixed to each other when the fitting piece 29 is fitted into the fitting recess 28.
According to this structure, since the 1st part 21 and the 2nd part 22 which comprise the main part 11 are detachable, replacement | exchange of the swelling material 4 is easy.
For example, when replacing the swelling material 4 that has absorbed water by water immersion, the lid 12 is removed from the main portion 11, the main portion 11 is disassembled into a first portion 21 and a second portion 22, and the swelling material 4 is replaced with a new one. It can be reassembled by exchanging the parts and combining the first part 21 and the second part 22 again.

As shown in FIGS. 4 and 5, the lid portion 12 includes a rectangular top plate portion 23, side wall portions 24 and 24 depending on the long side portions 23 a and 23 a of the top plate portion 23, and side wall portions 24 and 24. And a receiving member 25 depending from the top plate part 23.
The side wall portion 24 is formed in a rectangular shape, and a substantially rectangular stopper portion 27 protruding downward is formed at a lower end 24a thereof.
The stopper portion 27 restricts the ascent of the movable piece 5, and its lower surface is in a direction along the top plate portion 23.
Two stopper portions 27 are formed on each side wall portion 24 at intervals in the length direction of the lid portion 12 (longitudinal direction of the top plate portion 23; hereinafter, simply referred to as the length direction). .

As shown in FIGS. 1, 3, and 4, the receiving member 25 has a plate shape extending in the length direction and is formed substantially parallel to the side wall portion 24.
A receiving concave portion 25a having a shape curved in accordance with a bending imparting convex portion 30a of the movable piece 5 described later is formed at a substantially central portion in the length direction of the receiving member 25.

Locking portions 26 and 26 extending downward are formed on the top plate portion 23 or the side wall portion 24. The locking part 26 extends downward from the lower edge of the side wall part 24, and a locking claw 26 a that can be locked to the locking recess 34 of the movable piece 5 is formed at the tip of the locking part 26.
One locking portion 26 is formed closer to one side wall than one side portion 24 than the central portion in the length direction of the lid portion 12. The other locking portion 26 is formed on the other end side from the central portion in the length direction of the lid portion 12 and closer to the other side wall portion 24.

The movable piece 5 includes a bending imparting portion 30 and two arm portions 31, 31 extending from the bending imparting portion 30, and is accommodated in the container 3.
On the upper surface of the bend imparting portion 30, a bend imparting convex portion 30a having a curved surface and projecting in a direction perpendicular to the arm portion 31 (upward in the figure) is formed. The bending shape (curvature radius) of the bending imparting convex portion 30a is determined by the amount of bending to be given to the detection optical fiber 2.

The bend imparting portion 30 is formed with groove-like posture maintaining portions 32 and 32 along the vertical direction.
The posture maintaining portion 32 is a groove formed on both side surfaces 5a and 5a of the movable piece 5, and has a shape corresponding to the engaging portion 18 which is a protrusion formed on the side wall portion 14. When 18 is inserted and engaged, the movable piece 5 is prevented from tilting, and the posture of the movable piece 5 (the posture extending in the length direction of the main portion 11) is maintained.
Contrary to the illustrated example, the posture maintaining portion 32 may be a protrusion along the vertical direction, and the engaging portion 18 may be formed in a groove shape along the vertical direction that can be engaged therewith.

The arm portions 31 and 31 have substantially the same length as each other, and extend in opposite directions from the bend imparting portion 30.
A locking recess 34 that locks the locking claw 26 a of the locking portion 26 is formed on the one side surface 5 a at the distal end portion of the one arm portion 31. A locking recess 34 that locks the locking claw 26 a is formed on the other side surface 5 a at the tip of the other arm portion 31.
The movable piece 5 is arranged so as to extend in the length direction of the main portion 11, and the tips of the arm portions 31, 31 reach the vicinity of the end wall portions 15, 15 in the illustrated example.

Guide protrusions 33 and 33 are formed on both side surfaces 5 a and 5 a of the arm portion 31 to be inserted into the guide portion 17 of the side wall portion 14.
The width of the guide protrusion 33 (the dimension in the length direction) is preferably substantially the same as or slightly smaller than the width of the guide portion 17.
In the state shown in FIG. 1, the movable piece 5 is in the lowest lowered position, and the guide protrusion 33 is locked to the lower end of the guide portion 17.

As the swelling material 4, it is preferable to select a material that expands when it absorbs water and increases its volume, shrinks when dried and decreases its volume. If a material having a volume corresponding to the water content is used, it is possible to detect water in multiple times.
As the swelling material 4, a polyalkylene oxide water-absorbing resin is preferably used.
The swelling material 4 is disposed between the movable piece 5 and the bottom plate portion 13.
As shown in FIG. 1, the volume is small in the dry state and the movable piece 5 is not pushed up. However, as shown in FIG. 2, when water is absorbed and swollen, the movable piece 5 can be pushed up by increasing the volume. The swelling material 4 preferably returns to the contracted state shown in FIG. 1 when dried.

As shown in FIG. 6, the immersion sensor 1 can be provided in each of the closures 7 formed at intervals in a plurality of locations of the optical fiber cable 6. As the detection optical fiber 2, an optical fiber core or an optical fiber cord drawn from the optical fiber cable 6 can be used.
In the illustrated example, a plurality of water immersion sensors 1 are provided at intervals in the cable length direction on the common optical fiber 2 for detection of the optical fiber cable 6 connected to the optical pulse tester 8. The optical pulse tester 8 is, for example, OTDR, BOTDR, or the like.

Next, the operation of the water immersion sensor 1 will be described.
As shown in FIG. 1, when the closure 7 is not flooded, the swelling material 4 is in a dry state, the volume is small, and the movable piece 5 is not pushed up. For this reason, the detection optical fiber 2 is not bent.
Therefore, even when test light enters the detection optical fiber 2 from the optical pulse tester 8, no backscattered light of incident light due to deformation of the detection optical fiber 2 is generated.

As shown in FIG. 2, when the water is immersed, the water flows into the container 3 from the inflow hole 19 or the like, and the swelling material 4 absorbs the water and swells to increase the volume.
For this reason, the movable piece 5 is pushed up by the swelling material 4. Since the guide protrusion 33 is inserted into the guide portion 17, the movable piece 5 rises along the guide portion 17. At this time, since the engaging portion 18 and the posture maintaining portion 32 are engaged, the posture of the movable piece 5 does not change (see FIGS. 7 and 8).
When the movable piece 5 is pushed up, the detection optical fiber 2 is bent between the bending applying convex portion 30a and the receiving concave portion 25a.

  When the detection optical fiber 2 is bent, incident light is scattered in the detection optical fiber 2, and the backscattered light is detected by the optical pulse tester 8. It should be noted that the position where the deformation has occurred (the distance from the optical pulse tester 8) can be specified to some extent based on the return time of the backscattered light.

As shown in FIGS. 7 and 8, when the movable piece 5 is raised and a predetermined bending is applied to the optical fiber for detection 2, the guide protrusion 33 comes into contact with the stopper portion 27, and the further rise is restricted. (This position is referred to as the highest lift position or maximum displacement position).
This position is a position where the detection optical fiber 2 is not excessively bent and a detectable bend is applied. At this position, the side pressure applied to the immersion detection optical fiber 2 is small, and excessive bending loss does not occur.

At this highest position, the locking claw 26 a of the locking portion 26 of the lid 12 is locked to the locking recess 34 of the movable piece 5. This prevents the movable piece 5 from being lowered, so that the bent state of the water detection optical fiber 2 is maintained. For this reason, it is possible to reliably detect the occurrence of water immersion.
The submersion sensor 1 in which the movable piece 5 is locked to the locking portion 26 can be reused when the operator opens the lid portion 12 and removes the movable piece 5 from the lid portion 12.

Thus, in the water immersion sensor 1, since the stopper 3 that restricts the displacement of the movable piece 5 is formed in the container 3, the highest rise position of the movable piece 5 is excessively bent in the detection optical fiber 2. It can be set as the position which gives the detection bending to the optical fiber for detection, without giving a loss.
Since excessive loss does not occur in the detection optical fiber 2, even when one of the plurality of water immersion sensors 1 provided in series with the detection optical fiber 2 detects water immersion, the detection performance of the other water immersion sensors 1 is detected. Can be maintained.

As shown in FIG. 9, the main part 11 may be an integrally molded product.
When the integrally formed main portion 11 is used, there is an advantage that the number of parts can be reduced and the number of assembly steps can be reduced.

  The formation position of the stopper portion 27 is not limited to the lid portion 12 and may be the main portion 11.

It is a front view which shows an example of the water immersion sensor which concerns on this invention, and shows the state by which bending is not provided to the optical fiber for detection. It is a front view which shows the water immersion sensor shown in FIG. 1, and shows the state by which bending was provided to the optical fiber for detection. It is a perspective view which shows the water immersion sensor shown in FIG. It is a disassembled perspective view which shows the water immersion sensor shown in FIG. It is a perspective view which shows the cover part of the water immersion sensor shown in FIG. It is a block diagram which shows the optical fiber track | line which can apply the water immersion sensor which concerns on this invention. It is explanatory drawing which shows operation | movement of the movable piece in the water immersion sensor shown in FIG. It is explanatory drawing which shows operation | movement of the movable piece in the water immersion sensor shown in FIG. It is a disassembled perspective view which shows the other example of the water immersion sensor which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Submerged sensor, 2 ... Optical fiber for detection, 3 ... Container, 4 ... Swelling material, 5 ... Movable piece, 11 ... Main part, 11a ... Upper opening , 12 ... Lid, 17 ... Guide, 18 ... Engagement, 27 ... Stopper, 25a ... Receiving recess, 30a ... Bending imparting projection, 32 ... Posture maintenance part, 33 ... guide protrusion.

Claims (6)

A submersion sensor installed at a plurality of locations of the detection optical fiber (2) at intervals in the length direction of the detection optical fiber,
A container (3) into which the detection optical fiber is drawn, a swelling material (4) provided in the container, and the detection optical fiber displaced by swelling of the swelling material due to water immersion in the container. A movable piece (5) for bending the
The container includes a guide portion (17) that guides the displacement of the movable piece in a direction in which the detection optical fiber is bent, and a stopper portion that restricts the displacement of the movable piece along the guide portion ( 27) is formed,
The stopper portion is formed so that the displacement of the movable piece is a maximum displacement position, and can be regulated at a bending application position capable of suppressing a side pressure applied to the detection optical fiber,
The submerged sensor (1), wherein the movable piece has a locking portion that is locked to the container at the bending application position to maintain the bent state of the optical fiber for water detection. The guide part is a slit-like hole or groove formed in the container;
The movable piece has a guide projection (33) to be inserted into the guide portion, and the guide projection can be displaced in the bending direction by moving along the guide portion,
2. The water immersion sensor according to claim 1, wherein the stopper portion restricts displacement of the movable piece when the guide protrusion comes into contact with the predetermined bending position. 3. On the movable piece, a posture maintaining portion (32) that is a groove or a ridge along the displacement direction is formed,
The engagement body (18) which is a protrusion or groove having a shape conforming to the posture maintaining portion is formed in the container so as to be engageable with the posture maintaining portion. Or the water immersion sensor of 2. The container comprises a main part (11) having an upper opening (11a) and a lid part (12) for closing the upper opening,
The movable piece has a bending imparting convex portion (30a) that imparts bending to the optical fiber for detection,
The lid portion has a receiving concave portion (25a) having a shape conforming to the bending imparting convex portion of the movable piece,
The water immersion sensor according to any one of claims 1 to 3, wherein the receiving concave portion can bend the detection optical fiber between the bending imparting convex portion.   The intrusion sensor according to claim 4, wherein the stopper portion is formed on the lid portion. The water immersion sensor according to any one of claims 1 to 5 is installed at a plurality of locations of the detection optical fiber (2) at intervals in the length direction of the detection optical fiber,
The detection optical fiber is connected to an optical pulse tester that detects backscattered light from the detection optical fiber.

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