JP2008233601A - Closure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a closure which allows a connecting point of a cable to be simply and surely protected from submersion under water. <P>SOLUTION: On the bottom face inside the closure 1 in which optical cables 2a, 2b are drawn, a gas releasing unit 3 is arranged which is equipped with: a gas supply port 31 for releasing compressed filling gas inside a gas cylinder 36; an opening/closing movable piece 310 for switching gas release by switching the gas supply port from a closed state to an open state; a contact member 33 that comes into contact with the opening/closing movable piece to hold it in the closed state; a second opening spring 34 that imparts a pressing force to the contact member 33 to switch the opening/closing movable piece to the open state; and a transfer regulating member 32 that, against the pressing force of the second opening spring, comes into contact with the contact member to stop it and to hold the opening/closing movable piece in the closed state. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a closure that protects a connection point of a cable from flooding.

The connection point of the cable is housed and protected in an airtight connection point protective case usually called a closure. For example, the cable may be laid in an underground pipeline or in a high place above the ground. In either case, the connection point is accommodated in a closure, so that it can be prevented from being flooded from the outside. It is protected against it.
Even when a pinhole or the like occurs in the closure, a maintenance measure is taken to prevent water from entering the closure.

For example, when connecting a metal cable with a closure, an inert gas such as dry air is sent into the metal cable from the end of the metal cable on the side of the building at a pressure of atmospheric pressure or higher. As a result, the delivered inert gas reaches the inside of the closure from the inside of the cable and maintains the pressure inside the closure at a pressure equal to or higher than the atmospheric pressure, thereby preventing water from entering the inside of the closure. Such a maintenance method from flooding is usually called a “gas maintenance method” (see, for example, Non-Patent Document 1). The “gas maintenance method” can be applied because the density of the metal cable is relatively small, the gas flow resistance in the metal cable is small, and the inert gas can be easily supplied into the closure.
Electronic Information Communication Handbook, 7-10 “Communication Line”, IEICE (2000)

On the other hand, in the case of an optical cable or the like having a high cable density, the “gas maintenance method” cannot be applied because the gas flow resistance in the cable is large. This is because an inert gas having a sufficient pressure cannot be supplied into the closure as the distance from the inert gas supply end of the cable increases.
Therefore, conventionally, there has been a problem that a flood prevention measure cannot be applied to a cable having a large gas flow resistance, such as an optical cable, in addition to increasing the airtightness of the closure.
In addition, the airtightness of the closure is checked by, for example, sealing dry air at a pressure higher than atmospheric pressure into the closure from a gas valve attached to the closure body and checking for gas leaks from the joints of the closure. it can. However, even if there is no gas leakage immediately after construction, the airtightness may be reduced due to deterioration over time, and there is no method for reliably protecting the connection point of the cable from flooding over a long period of time.

  This invention is made | formed in view of the said situation, and makes it a subject to provide the closure which can protect the connection point of a cable from flooding simply and reliably.

In order to solve the problem,
The invention according to claim 1 is a closure, and includes a shut-off valve provided in a gas supply port for discharging compressed and filled gas in a gas cylinder in a closure sleeve into which a cable is drawn. A valve opening unit for releasing the gas in the gas cylinder from the gas supply port by switching from the closed state to the open state is provided. The gas includes dry air, nitrogen gas, carbon dioxide (CO ₂ ), and two kinds thereof. Any of the above mixed gases, wherein the valve opening unit directly connects the open / close valve and the open / close switching movable piece protruding from the open / close valve, or the opening / closing movable piece. The opening / closing valve is opened from the closed position where the opening / closing valve is closed by biasing it via a biasing force transmitting member that is in contact with or connected to the protruding portion protruding from the opening / closing valve. An opening spring for moving to the open position, and a movement for preventing movement of the opening / closing movable piece or the urging force transmitting member by the urging force of the opening spring against the urging force of the opening spring The movement restricting member is formed of a material that collapses or dissolves by contact with water, and the protrusion of the movable piece for opening and closing, or the protrusion directly or the biasing force transmitting member. The opening / closing movable piece or the urging force is provided in one or a plurality of places in contact with a component of the urging mechanism that is urged by the urging force of the opening spring via The movement of the transmission member due to the biasing force of the opening spring is blocked, and the valve opening unit is moved forward by the biasing force of the opening spring by the movement restricting member collapsing or dissolving due to contact with water. The opening / closing movable piece of the opening / closing valve is moved from the closed position to the open position, and the gas in the gas cylinder is released from the gas supply port.
The invention according to claim 2 is a closure, and includes an on-off valve provided in a gas supply port for releasing compressed and filled gas in a gas cylinder in a closure sleeve into which a cable is drawn. A valve opening unit for releasing the gas in the gas cylinder from the gas supply port by switching from the closed state to the open state is provided. The gas includes dry air, nitrogen gas, carbon dioxide (CO ₂ ), and two kinds thereof. The open / close valve is an open / close switching movable piece incorporated in the open / close valve as a variable projection amount, and the open / close movable piece projects from the open / close valve. An opening spring for biasing, and the valve opening unit is collapsed or brought into contact with water by contact with the on-off valve, an abutting member in contact with the projecting portion of the opening / closing movable piece, and water. A movement restricting member made of a material to be understood, and one or a plurality of the movement restricting members provided in contact with one or both of the on-off valve and the contact member are resistant to the biasing force of the opening spring. Thus, an increase in the distance between the on-off valve and the contact member is prevented, the state where the open / close movable piece is pushed into the on-off valve is maintained, and the movement restricting member is brought into contact with water. By collapsing or melting, the movable piece for opening and closing is moved from the closed position where the movable piece for opening and closing is pushed into the on-off valve to the open position where it is projected from the on-off valve by the biasing force of the opening spring and opens the on-off valve. The closure is characterized in that the gas in the gas cylinder is discharged from the gas supply port.
According to a third aspect of the present invention, the separation spring for biasing one or both of the on-off valve and the contact member to the valve opening unit to separate the on-off valve and the contact member. The movement restricting member prevents an increase in the distance between the on-off valve and the abutting member against an urging force of the separation spring. It is a closure.
The invention according to claim 4 is a closure, and includes an on-off valve provided in a gas supply port for releasing compressed and filled gas in a gas cylinder in a closure sleeve into which a cable is drawn. A valve opening unit for releasing the gas in the gas cylinder from the gas supply port by switching from the closed state to the open state is provided. The gas includes dry air, nitrogen gas, carbon dioxide (CO ₂ ), and two kinds thereof. The open / close valve includes an open / close switching movable piece incorporated in the open / close valve as a variable amount of protrusion, and the valve opening unit includes the open / close movable piece. The on-off valve disposed at a closed position where the projecting dimension from the on-off valve is larger than the open position, and the projecting portion of the open / close movable piece is pressed to make the open / close movable piece an on-off valve. Collapse by contact with water, a contact member for entrainment, an opening spring that biases one or both of the on-off valve and the contact member to bring the on-off valve and the contact member closer to each other Alternatively, it is made of a material that dissolves, and is provided in contact with one or both of the on-off valve and the abutting member, and prevents access between the on-off valve and the abutting member against the biasing force of the opening spring. One or a plurality of movement restricting members that are movable, and the movable member for opening and closing pressed against the contact member by the biasing force of the opening spring when the movement restricting member collapses or dissolves by contact with water. The closure is characterized in that the piece is moved from the closed position to the open / close valve and moved to an open position to open the open / close valve to release the gas in the gas cylinder from the gas supply port.
The invention according to claim 5 is a stem in which the movable piece for opening and closing is incorporated in the housing of the on-off valve and is urged so as to protrude from the housing by a protruding spring provided on the on-off valve. The closure according to any one of claims 2 to 4, further comprising a gas discharge hole that opens to a protruding portion protruding from the on-off valve.
According to a sixth aspect of the present invention, one of the on-off valve and the abutting member is fixed in the closure sleeve, and the movement restricting member resists the biasing force of the opening spring, The closure according to any one of claims 2 to 5, wherein the other movement of the contact member is restricted.
The invention according to claim 7 is the closure according to any one of claims 1 to 6, wherein the valve opening unit is arranged at a bottom portion in the closure.
The invention according to claim 8 is a closure, wherein a gas supply port for releasing the compressed and filled gas in the gas cylinder is provided in the closure sleeve into which the cable is drawn, and the gas includes dry air and nitrogen gas. , Carbon dioxide (CO ₂ ) and a mixed gas of two or more of these, and the gas supply port is sealed with a sealing member made of a material whose opening is collapsed or dissolved by contact with water It is a closure characterized by being.
The invention according to claim 9 is the closure according to claim 8, wherein the gas supply port is provided at a bottom portion in the closure.
The invention according to claim 10 is the closure according to any one of claims 1 to 9, wherein the gas cylinder is installed outside the closure sleeve.
The invention according to claim 11 is the closure according to any one of claims 1 to 10, wherein the movement restricting member or the sealing member is made of rock salt or quicklime.
The invention according to claim 12 is characterized in that the filling amount of the gas is an amount capable of maintaining the pressure in the closure at least 0.65 atm higher than the atmospheric pressure at room temperature. The closure according to one item.
The invention according to claim 13 is the closure according to any one of claims 1 to 12, further comprising an inundation detection sensor provided therein.
The invention according to claim 14 is the closure according to any one of claims 1 to 13, wherein gas permeation suppression means is provided in an exposed cross section of the cable drawn into the inside.

  According to the present invention, the connection point of the cable can be protected from flooding simply and reliably.

Hereinafter, the present invention will be described in detail with reference to the drawings.
The closure of the present invention can prevent further flooding even if there is a gap such as a pinhole, resulting in rapid flooding. During this time, the location of the flooding can be identified and repaired. It can be easily and reliably protected from flooding.
For example, the conventional “gas maintenance system” closure is intended to prevent any water from entering the closure, whereas the closure according to the present invention absorbs moisture in the initial stage of water immersion. It is used to prevent further inundation and is completely different from the technical idea in the prior art.

FIG. 1 is a front view illustrating a closure for underground laying according to the present invention.
The optical fiber 20a protrudes from the cable cross-section 200a exposed in the closure 1 of the multi-fiber optical cable 2a. Similarly, from the cable cross-section 200b exposed in the closure 1 of the multi-fiber optical cable 2b, An optical fiber 20 b is projected, and the tips of the protruding portions of the optical fibers 20 a and 20 b are optically connected at an optical connection point 21. The optical fibers 20a and 20b branched out from the optical cables 2a and 2b are optically connected to the detection optical fiber 20c via the optical connection points 22 and 23, and the detection optical fiber 20c is connected to the inundation detection unit 40. The water intrusion detection sensor 4 is configured by being drawn in. The inundation detection sensor 4 is of a type that detects inundation from deformation of the detection optical fiber 20c using an optical pulse tester (OTDR), although details are omitted here. That is, an optical fiber in which a stress applying member is brought into contact with the optical fiber for detection, and a swelling member that is swollen by submerged water is disposed on the side of the stress applying member that faces the side on which the optical fiber for detection is disposed. A sensor (for example, see Japanese Patent Laid-Open No. 3-197844), which is driven by a stress applying member as the swelling member swells and deforms the detection optical fiber 20c such as bending or elongation strain.
In the present invention, it is not always necessary to provide an inundation detection sensor inside the closure, but if provided, it is advantageous for shortening the time until the start of the repair of the closure. The number of inundation detection sensors provided inside the closure is not particularly limited, but usually one is sufficient. Further, the type of the inundation detection sensor is not limited to the one shown here, and any conventionally known one may be used.
As described above, the optical connection points 21, 22 and 23 are stored in the closure 1 while ensuring waterproofness, and the water intrusion into the closure 1 can be detected by the water immersion detection sensor 4.

  Reference numeral 3 denotes a gas discharge unit including a gas supply port 31 including an opening spring, a movement restricting member 32, a contact member 33, and a second opening spring 34, which will be described later. Among them, the gas supply port 31 is connected to a gas cylinder 36 provided outside the closure 1 through a pipe 35 penetrating the side surface of the closure 1 and drawn into the inside, and the gas compressed and filled in the gas cylinder 36. Can be discharged into the closure 1. And the gas discharge | release unit 3 is arrange | positioned in the bottom part in the closure 1 and the said flooding detection sensor 4 and adjoining.

The gas filled in the gas cylinder 36 may be any gas as long as it does not deteriorate the closure, the cable, and the like and has no problem for disaster prevention. Specifically, for example, any one of dry air, nitrogen gas, and carbon dioxide gas (CO ₂ ) is used. Alternatively, a mixed gas of two or more of these gases may be used.
The material of the pipe 35 is not particularly limited as long as it has pressure resistance against the supplied gas.

For example, considering a case where a gap such as a pinhole is generated in the closure sleeve 10 and this is the cause of water intrusion into the closure 1, water immersion is prevented if the pressure in the closure 1 is higher than atmospheric pressure at this time. However, flooding can be more stably prevented as the differential pressure from atmospheric pressure increases.

For example, considering a case where a gap such as a pinhole occurs in the closure and this is the cause of inundation into the closure, if the pressure in the closure is higher than the atmospheric pressure at this time, inundation is prevented. The larger the differential pressure from atmospheric pressure, the more stable the flooding can be prevented.
From this point of view, the storage amount of the carbon dioxide generating substance is the pressure in the closure at the time of water immersion, and from this point of view, the filling amount of the gas into the gas cylinder 36 is the pressure in the closure 1 at the time of water immersion. Is preferably an amount that can be maintained at least 0.3 atmospheres higher than atmospheric pressure at room temperature, more preferably an amount that can be maintained at least 0.4 atmospheres higher, and an amount that can be maintained at least 0.65 atmospheres higher Is particularly preferred.
The increase in pressure in the closure 1 due to the released gas varies depending on the internal volume of the closure 1 and the like even with the same gas discharge amount. Also, if it takes about one week from the detection of inundation into the closure 1 to the start of repair of the closure 1, depending on the size of the gap such as pinholes or the state of the cable cross section as described later, During this time, part of the released gas is lost due to outflow to the outside of the closure 1. Therefore, it is preferable that an excessive amount of the gas is filled in the gas cylinder 36 in advance in consideration of the form and the internal volume of the closure to be used.
In the present invention, “normal temperature” means a temperature at which the closure is exposed in the installation environment, and specifically, a temperature in the range of about 0 to 40 ° C.

Next, the gas discharge unit 3 will be described in more detail.
(First embodiment)
FIG. 2 is a front view illustrating the gas discharge unit 3. FIG. 2 (a) is a front view at normal times, and FIG.
The gas supply port 31 shown here also serves as an on-off valve. The same applies to other embodiments described below. Specifically, it includes an opening / closing movable piece 310 for switching between opening and closing, which is incorporated as a variable amount of protrusion, and an opening spring 312 for biasing the opening / closing movable piece 310 so as to protrude from the gas supply port 31. ing. Moreover, the movable piece 310 for opening and closing has a substantially hollow cylindrical shape and also serves as a gas flow path. One end of the movable piece 310 is opened (hereinafter abbreviated as a gas discharge hole), and gas can be discharged from the gas discharge hole. . The gas supply port 31 is closed when the open / close movable piece 310 is pushed into the main body of the gas supply port 31, but the protruding dimension of the open / close movable piece 310 from the gas supply port 31 is larger than the closed position. The large open position releases the gas in the gas cylinder 36.

  That is, in the present embodiment, the opening spring 312 functions as a “protruding spring”. Therefore, the opening / closing movable piece 310 is incorporated into a housing (gas supply port) of the opening / closing valve, It can be regarded as a stem having a gas discharge hole that is urged so as to protrude from the housing by a protruding spring provided in the on-off valve and opens to a protruding portion protruding from the on-off valve.

  The gas supply port 31 is fixed on the bottom surface of the closure 1, and the fixing method is not particularly limited as long as it can be stably fixed even in the presence of water, and for example, screwing or the like may be used.

2A, one end of the second opening spring 34 is fixed to a support body portion 340 fixedly arranged on the bottom surface of the closure 1, and the contact member 33 having a substantially rectangular parallelepiped shape is connected to the other end. However, it is attached so that the bottom surface thereof is not fixed to the bottom surface of the closure 1. Then, the corresponding contact member 33 receives a biasing force (tensile force) from the second opening spring 34 in a substantially central axis direction of the second opening spring 34, that is, in a direction indicated by an arrow in the drawing. This is because the length in the central axis direction of the second opening spring 34 in this state is longer than the natural length. Further, a substantially rectangular parallelepiped movement restricting member 32 which is in contact with the surface of the abutting member 33 facing the support body portion 340 is fixed on the bottom surface of the closure 1, and a tensile force from the second opening spring 34. Against this, the abutting member 33 is stationary on the bottom surface of the closure 1. Further, in this stationary state, the contact member 33 contacts the protruding portion of the opening / closing movable piece 310 and presses the opening / closing movable piece 310 toward the gas supply port 31 body against the biasing force of the opening spring 312. Thus, an increase in the distance between the gas supply port 31 and the contact member 33 is prevented, and the closed state of the gas supply port 31 is maintained.
In other words, when the stationary state by the movement restricting member 32 is released, the contact member 33 is pulled back by the spring 34 in the substantially central axis direction of the second opening spring 34 and is opened and closed by the biasing force of the opening spring 312. The movable piece 310 protrudes from the gas supply port 31 and moves from the closed position to the open position, and the gas supply port 31 is opened. In the present embodiment, the gas supply port 31, the contact member 33, the second opening spring 34, and the movement restricting member 32 function as a valve opening unit.
The gas supply port 31, the opening / closing movable piece 310, the movement restricting member 32, the contact member 33, and the second opening spring 34 are arranged on a substantially straight line.

The movement restricting member 32 is made of a material that collapses or dissolves upon contact with water. Here, the collapse means that the strength is weaker than before contact with water.
The material of the movement restricting member 32 is not particularly limited as long as it has such properties. Specifically, rock salt, lime, and the like can be exemplified as preferable ones.
The outer shape of the movement restricting member 32 is a substantially rectangular parallelepiped here, but is not particularly limited as long as the contact member 33 can be stably stopped, and is in surface contact with the contact member 33. It is preferable that it is made so.

  The method of fixing the movement restricting member 32 on the bottom surface of the closure 1 is not particularly limited, and any method may be used as long as the contact member 33 can be stably stopped at normal times. Then, the material may be appropriately selected in consideration of the material of the movement restricting member 32. For example, a clamp is provided in a region on the bottom surface of the closure 1 that does not hinder the movement of the second opening spring 34 and the one that moves in conjunction with the movement of the spring 34 (here, the contact member 33). It may be sandwiched and fixed. Or you may adhere | attach the bottom face of the movement control member 32 on the bottom face of the closure 1 through an adhesive bond layer.

The material of the contact member 33 is not particularly limited as long as it is difficult to be deformed by the pressing of the opening / closing movable piece 310, and specific examples include wood, metals, plastics, and the like. Among these, since the stationary state can be stably maintained by the movement restricting member 32, one having a large specific gravity is preferable.
The outer shape of the abutting member 33 is a substantially rectangular parallelepiped here, but is not particularly limited as long as the movable member for opening and closing 310 can be reliably pushed toward the main body of the gas supply port 31. However, it is preferable that the bottom surface of the contact member 33 is in surface contact with the bottom surface of the closure 1 and has a large contact area at that time. This is because the contact member 33 can be stably placed on the bottom surface of the closure 1 by doing in this way.

  Although not shown here, at least a portion of the surface of the contact member 33 that faces the opening / closing movable piece 310 that is in contact with the opening / closing movable piece 310 is airtight and flexible, such as rubber. It is preferable to provide a sheet or protrusion of a material having both of the above. By doing in this way, the gas leak from the movable piece 310 for opening and closing at normal time can be prevented reliably.

  In the closure 1 of this embodiment having such a configuration, when a pinhole or the like is generated in the closure sleeve 10 and water is immersed in the closure 1, the water that has reached the bottom immediately contacts the movement restricting member 32, As a result, the movement restricting member 32 is collapsed or dissolved, and the stationary state of the contact member 33 cannot be maintained. For example, if the submerged water is accumulated on the bottom surface in the closure 1, the movement restricting member 32 is collapsed or dissolved from the lower part. And even if the movement restricting member 32 does not collapse or dissolve by water as a whole, the movement restricting member 32 collapses when it cannot resist the force exerted by the contact member 33 due to the biasing force from the second opening spring 34. There are many. As a result, as shown in FIG. 2B, the contact member 33 is pulled away from the opening / closing movable piece 310 by the tensile force from the second opening spring 34, and the gas discharge hole of the opening / closing movable piece 310 is formed. Simultaneously with the opening, the opening / closing movable piece 310 is released from being pushed into the main body of the gas supply port 31 by the contact member 33, so that the gas supply port 31 is opened and the gas filled in the gas cylinder 36 is It is discharged into the closure 1 through the pipe 35 and the gas supply port 31.

  In addition, although the example using the one movement control member 32 is shown here, it is not limited to this in this invention, You may use a some movement control member.

(Second embodiment)
FIG. 3 is a front view illustrating another example of the gas discharge unit 3. FIG. 3 (a) is a front view in a normal state, and FIG. 3 (b) is a front view in a state in which the gas discharge unit 3 is activated during flooding. In addition, the same code | symbol is attached | subjected to the component same as the component already demonstrated, and the detailed description is abbreviate | omitted. The same applies to the subsequent drawings.
The gas supply port 51 shown here is the same as that of the first embodiment shown in FIG. 2 except that the second opening spring 34 is attached and the attachment position of the pipe 35 is different. The opening spring 512 and the opening / closing movable piece 510 are the same as the opening spring 312 and the opening / closing movable piece 310.

3A, one end of the second opening spring 34 is fixed to a support portion 340 fixedly arranged on the bottom surface of the closure 1, and the gas supply port 51 is connected to the other end at the other end. It is attached so as to be in contact with the bottom surface of 1 without being fixed. The gas supply port 51 receives a tensile force from the spring 34 in the substantially central axis direction of the second opening spring 34, that is, in the direction indicated by the arrow in the drawing. This is because the length in the central axis direction of the second opening spring 34 in this state is longer than the natural length. Further, the movement restricting member 32 is fixed on the bottom surface of the closure 1 in contact with the surface of the gas supply port 51 facing the support portion 340, and the gas is resisted against the tensile force from the second opening spring 34. The supply port 51 is stationary on the bottom surface of the closure 1. On the other hand, the contact member 33 is fixedly disposed on the bottom surface of the closure 1, and the movable piece 510 for opening and closing the gas supply port 51 is directed toward the main body of the gas supply port 51 by the contact member 33 in this stationary state. The gas supply port 51 is closed by being pressed.
In other words, when the stationary state by the movement restricting member 32 is released, the gas supply port 51 is pulled back by the spring in the direction of the substantially central axis of the second opening spring 34 and opened.

  Except for the above points, this embodiment is the same as the first embodiment.

  When flooding occurs in the closure 1 of the present embodiment having such a configuration, the water that has reached the bottom quickly contacts the movement restricting member 32, whereby the movement restricting member 32 collapses or dissolves, and gas The supply port 51 cannot be kept stationary. As a result, as shown in FIG. 4B, the gas supply port 51 is pulled away from the contact member 33 by the tensile force from the second opening spring 34, and the gas discharge hole of the opening / closing movable piece 510 is opened. Simultaneously with the opening, the opening / closing movable piece 510 is released from being pushed into the main body of the gas supply port 51 by the contact member 33, so that the gas supply port 51 is opened and the gas filled in the gas cylinder 36 is It is discharged into the closure 1 through the pipe 35 and the gas supply port 51.

(Third and fourth embodiments)
In the case where a member having a relatively small specific gravity is used as the contact member 33 or the gas supply port 51, the configurations of the first and second embodiments can be further simplified. Specifically, for example, although not shown, in the first and second embodiments, the second opening spring 34 and the support body 340 may not be provided. When such simplification is performed in the first embodiment (third embodiment), when the movement restricting member 32 is dissolved or collapsed, the gas supply port 31 is fixed on the bottom surface of the closure 1. Due to the urging force of the opening spring 312, the contact member 33 is urged from the opening / closing movable piece 310, and the gas supply port 31 is opened. On the other hand, when the same simplification is performed in the second embodiment (fourth embodiment), when the movement regulating member 32 is dissolved or collapsed, the contact member 33 is fixed on the bottom surface of the closure 1. The gas supply port 51 is biased by the biasing force of the release spring 512, and the gas supply port 51 is opened.

(Fifth and sixth embodiments)
Furthermore, the modification of the said 3rd and 4th embodiment is illustrated in FIG.
In the present invention, for example, as shown in FIG. 7A, the gas supply port 31 and the contact member 33 may be connected by the second opening spring 34 without being fixed on the bottom surface of the closure 1. Good (fifth embodiment).
That is, the abutment member 33 is brought into contact with the protruding portion of the open / close movable piece 310 so that the open / close movable piece 310 is pushed toward the gas supply port 31 body and the gas supply port 31 is closed. While maintaining this state, the second opening spring 34 is connected to the gas supply port 31 and the contact member 33 such that the length in the central axis direction is shorter than the natural length. Then, one movement restricting member 32 is brought into contact with the surface opposite to the surface facing the contact member 33 with respect to the gas supply port 31, and the other movement restricting member 32 is made into The gas supply port 31 is brought into contact with the surface opposite to the surface facing the supply port 31, fixed on the bottom surface of the closure 1, and resists the urging force (repulsive force) of the second opening spring 34. And the contact member 33 are prevented from increasing in distance.
In this embodiment, when the movement restricting member 32 is dissolved or collapsed by water immersion or the like, the distance between the gas supply port 31 and the contact member 33 is increased by the urging force (repulsive force) of the second opening spring 34. Then, the gas supply port 31 is opened.

Alternatively, it may be as shown in FIG. 7B (sixth embodiment). That is, similarly to the case shown in FIG. 7A, the gas supply port 51 and the contact member 33 are arranged on the bottom surface of the closure 1 without being fixed. Then, one second opening spring 34 is maintained while maintaining the state in which the contact member 33 pushes the opening / closing movable piece 510 into the main body of the gas supply port 51 so that the gas supply port 51 is closed. One end of the gas supply port 51 is fixed to the surface opposite to the surface facing the contact member 33 of the gas supply port 51, and the other end of the closure 1 is closed. It fixes to the support body part 340 fixed on the bottom face. Further, the other second opening spring 34 is arranged so that its length in the central axis direction is longer than the natural length, and one end of the second opening spring 34 is opposite to the surface facing the gas supply port 51 of the contact member 33. The other end is fixed to the support body part 340 fixed on the bottom surface of the closure 1. Then, one movement restricting member 32 is brought into contact with the surface opposite to the surface facing the contact member 33 with respect to the gas supply port 51, and the other movement restricting member 32 is brought into contact with the contact member 33 with gas. The gas supply is made in contact with the surface opposite to the surface facing the supply port 51, fixed on the bottom surface of the closure 1, and resists the urging force (tensile force) of the second release springs 34, 34. An increase in the distance between the mouth 51 and the contact member 33 is prevented.
Also in this embodiment, when the movement restricting member 32 is dissolved or collapsed due to water immersion or the like, the distance between the gas supply port 51 and the contact member 33 is increased, and the gas supply port 51 is opened.

  Thus, in the fifth embodiment, one second opening spring 34 biases both the gas supply port 31 and the contact member 33, and in the sixth embodiment, the second opening spring 34 34 urges the gas supply port 51 and the contact member 33 separately to separate the gas supply port and the contact member 33 from each other. That is, the second opening spring 34 functions as a separation spring.

  In the fifth and sixth embodiments, an example in which both the gas supply port 31 and the contact member 33 are not fixed on the bottom surface of the closure 1 has been shown. However, in the fifth embodiment, the gas supply Either the port 31 or the contact member 33 may be fixed on the bottom surface of the closure 1. In this case, the second opening spring 34 urges the gas supply port 31 and the contact member 33 that are not fixed.

(Seventh embodiment)
FIG. 4 is a front view illustrating the gas release unit 3 when the configuration of the third embodiment is further simplified.
The gas release unit 3 of the present embodiment maintains the state where the movable opening / closing piece 310 is pushed toward the main body of the gas supply port 31, while the movable movable piece for opening / closing 310 and a part of the main body of the gas supply port 31 are made water and Are integrally sealed with a sealing member 62 made of a material that collapses or dissolves by contact. That is, the sealing member 62 closes the gas discharge hole of the opening / closing movable piece 310 and fixes the opening / closing movable piece 310 at the closed position where it is pushed toward the main body of the gas supply port 31. The sealing member 62 may be fixed to the gas supply port 31 using, for example, a binding tool.

  The sealing member 62 is made of the same material as the movement restricting member. And the external shape is not specifically limited unless the effect of this invention is impaired.

The gas supply port 31 may not be fixed on the bottom surface in the closure 1, but is preferably fixed because it can be stably installed. The fixing method may be the method described above.
When the gas supply port 31 is not directly fixed on the bottom surface in the closure 1, for example, the sealing member 62 may be fixed on the bottom surface by a method similar to the method for fixing the movement restricting member described above. .
Of course, the gas supply port 31 and the sealing member 62 may be individually fixed directly on the bottom surface in the closure 1.

  In the present embodiment, it is preferable that a sealing auxiliary member 313 made of a gas-impermeable material is interposed between the opening / closing movable piece 310 and the sealing member 62. Here, “gas impermeable” refers to the property of suppressing the permeation of the type of gas used in the present invention, and specific examples include glass, metals, plastics, and the like. Then, for example, these materials are appropriately formed, and the opening / closing movable piece 310 is inserted into the main body of the gas supply port 31 and mounted so as to seal the opening, and further sealed as described above. What is necessary is just to seal with the stop member 62. It is preferable that the sealing auxiliary member 313 is not fixed to the gas discharge hole of the opening / closing movable piece 310. In this way, by using the sealing auxiliary member 313 together, gas leakage at normal times can be reliably suppressed.

  When flooding occurs in the closure 1 of this embodiment having such a configuration, the water that has reached the bottom quickly contacts the sealing member 62, and the sealing member 62 collapses or dissolves, and the movable piece for opening and closing. The pushing state of 310 into the gas supply port 31 main body cannot be maintained. For example, if the submerged water accumulates on the bottom surface in the closure 1, the sealing member 62 collapses or dissolves from the lower part. The sealing member 62 often collapses at a stage where it cannot resist the urging force from the opening / closing movable piece 310 even if the entire sealing member 62 does not collapse or dissolve with water. As a result, the gas supply port 31 is opened, and the gas filled in the gas cylinder 36 is released into the closure 1.

  The gas discharge unit 3 of the present embodiment has the simplest configuration in the present invention and has the same effects as those of the other embodiments. Therefore, the closure provided with the unit is advantageous in terms of cost.

(Eighth embodiment)
FIG. 5 is a front view illustrating still another example of the gas discharge unit 3. FIG. 5 (a) is a front view in a normal state, and FIG. 5 (b) is a front view in a state in which the gas discharge unit 3 is activated during flooding.
In the present embodiment, the gas supply port 61 is opened in a state where the movable opening / closing piece 610 incorporated as a variable projection amount is pushed into the main body of the gas supply port 61, and releases the gas in the gas cylinder 36. The projecting dimension of the movable piece 610 from the gas supply port 61 is closed at a closed position larger than the open position.
In the present embodiment, the gas discharge hole 614 for discharging the gas is provided on the side surface in the vicinity of the end of the projecting portion of the opening / closing movable piece 610, and the contact member 33 is provided at the end of the projecting portion. The gas can be released to the outside even in a contact state.

In FIG. 5A, the contact member 33 is attached to the other end of the second opening spring 34 so that the bottom surface thereof is in contact with the bottom surface of the closure 1 without being fixed. The corresponding contact member 33 receives a repulsive force from the spring 34 in the substantially central axis direction of the second release spring 34, that is, in the direction indicated by the arrow in the drawing. This is because the length in the central axis direction of the second opening spring 34 in this state is shorter than the natural length. Further, the movement restricting member 32 is fixed on the bottom surface of the closure 1 in contact with the surface of the contact member 33 facing the gas supply port 61, and resists the repulsive force from the second opening spring 34. Thus, the contact member 33 is stationary on the bottom surface of the closure 1. The contact member 33 is stationary at a position separated from the opening / closing movable piece 610, and the approach between the gas supply port 61 and the contact member 33 is prevented. In this state, the opening / closing movable piece 610 is not pushed toward the main body of the gas supply port 61, and the gas supply port 61 is closed.
That is, when the stationary state by the movement restricting member 32 is released, the contact member 33 is pushed out by the spring in the substantially central axis direction of the second opening spring 34 and presses the protruding portion of the opening / closing movable piece 610. Then, the gas supply port 61 is opened by pushing the movable piece 610 for opening and closing toward the main body of the gas supply port 61. In the present embodiment, the gas supply port 61, the contact member 33, the second opening spring 34, and the movement restricting member 32 function as a valve opening unit.

  In the present embodiment, unlike the first embodiment, the surface of the contact member 33 that faces the movable piece 610 for opening and closing is not necessarily made of a material sheet or protrusion having both airtightness and flexibility such as rubber. There is no need to provide. This is because the gas supply port 61 is not closed in a state where the opening / closing movable piece 610 is pushed.

  Except for the above points, this embodiment is the same as the first embodiment.

  When water is generated in the closure 1 of this embodiment having such a configuration, the water that has reached the bottom quickly contacts the movement restricting member 32, thereby causing the movement restricting member 32 to collapse or dissolve and The stationary state of the contact member 33 cannot be maintained. As a result, as shown in FIG. 5 (b), the contact member 33 has its surface facing the gas supply port 61 pressed against the movable opening / closing piece 610 by the repulsive force from the second opening spring 34. The movable piece 610 for opening and closing is pushed toward the main body of the gas supply port 61, and the gas supply port 61 is opened. As a result, the gas filled in the gas cylinder 36 is released into the closure 1.

(Ninth embodiment)
FIG. 6 is a front view illustrating still another example of the gas discharge unit 3. FIG. 6 (a) is a front view in a normal state, and FIG. 6 (b) is a front view in a state in which the gas discharge unit 3 is activated during flooding.
The gas supply port 71 shown here is the same as that shown in the eighth embodiment except that the second opening spring 34 is attached and the attachment position of the pipe 35 is different.

In FIG. 6A, the gas supply port 71 is attached to the other end of the second opening spring 34 so that the bottom surface thereof is in contact with the bottom surface of the closure 1 without being fixed. The gas supply port 71 receives a repulsive force from the second opening spring 34 in a substantially central axis direction of the second opening spring 34, that is, in a direction indicated by an arrow in the drawing. This is because the length in the central axis direction of the second opening spring 34 in this state is shorter than the natural length. Further, the movement restricting member 32 is fixed on the bottom surface of the closure 1 in contact with the surface of the gas supply port 71 facing the contact member 33, and resists the repulsive force from the second opening spring 34. The gas supply port 71 is stationary on the bottom surface of the closure 1. The contact member 33 is fixed on the bottom surface of the closure 1 so as to be separated from the opening / closing movable piece 710, and the opening / closing movable piece 710 is not pushed toward the main body of the gas supply port 71, and the gas supply The mouth 71 is closed.
That is, when the stationary state by the movement restricting member 32 is released, the gas supply port 71 is pushed out by the spring in the direction of the substantially central axis of the second opening spring 34, and the movable piece 710 for opening and closing is in contact with the contact member 33. Is pushed into the main body of the gas supply port 71 to open the gas supply port 71.

  Except for the above points, this embodiment is the same as the eighth embodiment.

  When flooding occurs in the closure 1 of this embodiment having such a configuration, the water that has reached the bottom quickly contacts the movement restricting member 32, whereby the movement restricting member 32 collapses or dissolves, and gas The supply port 71 cannot be kept stationary. As a result, as shown in FIG. 6B, the opening / closing movable piece 710 of the gas supply port 71 comes into contact with the contact member 33 due to the repulsive force from the second release spring 34. Subsequently, the opening / closing movable piece 710 is pushed toward the main body of the gas supply port 71 to open the gas supply port 71. As a result, similarly to the eighth embodiment, the gas filled in the gas cylinder 36 is released into the closure 1.

(Tenth and eleventh embodiments)
Furthermore, the modification of the said 8th and 9th embodiment is illustrated in FIG.
In the present invention, for example, as shown in FIG. 7C, the gas supply port 31 and the contact member 33 may be connected by the second release spring 34 without being fixed on the bottom surface of the closure 1. Good (tenth embodiment).
In the fifth embodiment, in the fifth embodiment shown in FIG. 7A, the second opening spring 34 has a length in the central axis direction longer than the natural length, and the movement restricting member 32. May be fixed on the bottom surface of the closure 1 by contacting the opposing surfaces so as to prevent the gas supply port 31 and the contact member 33 from approaching each other.
In this embodiment, when the movement restricting member 32 is dissolved or collapsed by water immersion or the like, the gas supply port 31 and the contact member 33 approach each other due to the urging force (tensile force) of the second opening spring 34, and then The opening / closing movable piece 310 is pushed toward the main body of the gas supply port 31 to open the gas supply port 31.

Or you may make it show in FIG.7 (d) (11th embodiment). That is, in the sixth embodiment shown in FIG. 7B, the second opening spring 34 is set so that its length in the central axis direction is shorter than the natural length, and the movement restricting member 32 is connected to the gas What is necessary is just to make it contact on these opposing surfaces and to fix on the bottom face of the closure 1 so that the approach between the supply port 51 and the contact member 33 may be prevented.
Also in this embodiment, when the movement restricting member 32 is dissolved or collapsed due to water immersion or the like, the gas supply port 51 and the contact member 33 approach each other by the urging force (repulsive force) of the second opening spring 34, and then The opening / closing movable piece 510 is pushed toward the main body of the gas supply port 51 to open the gas supply port 51.

(Twelfth embodiment)
Up to this point, the gas supply port has also been illustrated as a gas supply port used in the present invention, which also serves as an open / close valve and is provided with an open / close switching movable piece incorporated in the open / close valve as a variable projection amount. However, the present invention is not limited to this, and any known gas supply port may be used as long as gas emission and emission suppression can be adjusted.
FIG. 8 is a diagram illustrating the gas discharge unit 3 having such a gas supply port, and is a view when the gas discharge unit 3 arranged on the bottom surface of the closure 1 is viewed from above. The gas supply port 81 shown here has an opening / closing valve 810 fixedly disposed at the tip thereof, and an opening / closing movable piece 811 closes the opening / closing valve 810 at the protruding tip of the opening / closing valve 810. Or it is protrudingly provided at a position where it can be opened. One end of an opening spring 812 is connected to the other end of the opening / closing movable piece 811, and the other end of the opening spring 812 has a length in the central axis direction of the spring 812 longer than a natural length. Thus, it is being fixed to the support body part 340 fixedly arrange | positioned on the closure 1 bottom face. The movement restricting member 32 abuts on the opening / closing movable piece 811 and is fixed on the bottom surface of the closure 1. Is stationary. In this state, the opening / closing movable piece 811 is held in a closed position that closes the opening / closing valve 810 and suppresses gas release.

  When flooding occurs in the closure 1 of the present embodiment having such a configuration, the water that has reached the bottom immediately comes into contact with the movement restricting member 32, thereby causing the movement restricting member 32 to collapse or dissolve. Then, the open / close movable piece 811 is moved from the closed position where the open / close valve 810 is closed to the open position where gas can be released by the urging force from the opening spring 812, the gas supply port 81 is opened, and the gas cylinder 36 is opened. The filled gas is released into the closure 1.

As described above, in the present embodiment, the on-off valve 810 is opened using the tensile force of the opening spring 812. As in the other embodiments, the opening spring 812 is moved in the direction of its central axis. The opening / closing valve 810 may be opened by utilizing the repulsive force of the opening spring 812 when the movement restricting member 32 is collapsed or melted.
Further, for example, the opening / closing movable piece 811 may be connected not via the opening spring 812 but via a member that transmits the urging force.
Further, if the movement restricting member 32 can prevent the movement of the opening / closing movable piece 811, the movement restricting member 32 does not contact the opening / closing movable piece 811 but contacts with any other member involved in the urging of the opening / closing movable piece 811. May be arranged. For example, the entire length of the spring 812 may be covered with the movement restricting member 32 while maintaining the opening spring 812 so that its length in the central axis direction is longer than the natural length as described above.
A plurality of movement restricting members 32 may be used.

  The twelve embodiments have been specifically described so far. However, the closure of the present invention is not limited to the embodiments described above as long as it has the characteristics described above. .

For example, up to here, a coiled spring is shown as an opening spring (including a second opening spring). However, in the present invention, any one that can apply a biasing force (tensile force or repulsive force) can be used. Various types such as a leaf spring can be used.
The urging force of the release spring can be adjusted by, for example, appropriately selecting the form and material of the spring according to the type of contact member, gas supply port, etc., the pressure of the gas to be released, etc. Any adjustment may be made as appropriate.

  Although not shown in the drawings, for example, when water is pushed into the closure 1, the one to be pushed out by the repulsive force of the second opening spring is provided with a holding body that guides its movement on the bottom surface in the closure 1. Also good. By doing in this way, a gas supply port (opening-closing valve) can be opened more reliably.

  Moreover, in each said embodiment, although the piping 35 has shown the example pulled inside from the side surface of the closure 1, the inside drawing location is not specifically limited unless the effect of this invention is prevented. For example, it may be from the top of the closure 1 or from the bottom. However, the side of the closure 1 is preferable in consideration of the ease of installation of the closure and the configuration inside the closure.

  Furthermore, although the gas cylinder 36 is installed outside the closure sleeve 10 here, it may be installed inside the closure 1. In this case, it is not necessary to provide a hole for drawing in the pipe 35 in the closure 1, and the risk of water intrusion into the closure 1 can be reduced. In this case, the gas supply port may be integrated with the cylinder without using the pipe 35.

In order to maintain the pressure in the closure higher than the atmospheric pressure for a long time, as described above, it is sufficient to pre-fill the cylinder with an excessive amount, but for example, it is drawn into the closure. Gas permeation suppression means may be provided on the exposed cross section of the cable.
The gas permeation suppression means here is not particularly limited as long as it can suppress the ingress of gas from the cable cross section into the cable. Specifically, a method of applying a gas permeation suppressant such as jelly to the cable cross section (for example, the cable cross sections 200a and 200b in FIG. 1) can be mentioned.

  The gas released into the closure due to water immersion can protect the inside of the closure from water immersion during the time from the water immersion to the start of the repair of the closure. And as time passes, the gas mainly enters the cable from the section of the cable exposed in the closure and flows through the cable, and in some cases, it flows out of the closure from the flooded part. The amount of inert gas decreases and eventually the pressure in the closure becomes about the same as the atmospheric pressure. However, the closure may be repaired while the pressure in the closure is maintained higher than atmospheric pressure, for example, at least 0.3 atmosphere higher than atmospheric pressure. For example, as described above, it is possible to identify a flooded closure using a flood detection sensor provided in the closure.

The present invention is intended for all cables that require protection of connection points by mounting closures, such as optical cables and metal cables, but it is particularly difficult to protect against flooding by the conventional “gas maintenance method”. It is suitable for the existing optical cable.
In the above description, the cable laid underground is described as an example, but the present invention can also be applied to an aerial cable laid on a high ground.

According to the present invention, it is possible to easily and surely prevent further flooding into the closure within the time required for the repair start. Moreover, the gas used is an inert gas and does not damage the closure and the cable. Therefore, the cable connection point can be protected stably at low cost.
Furthermore, it is possible to reliably protect the connection points of cables that are difficult to protect from flooding by the conventional “gas maintenance method”.

  The present invention can be used to protect cable connection points such as optical cables.

It is a front view which illustrates the closure of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a front view which illustrates 1st embodiment of the gas discharge | release unit in this invention, (a) is a front view in normal time, (b) is a front view of the state which act | operated at the time of flooding. It is a front view which illustrates 2nd embodiment of the gas discharge | release unit in this invention, (a) is a front view in normal time, (b) is a front view of the state which act | operated at the time of flooding. It is a front view which illustrates 7th embodiment of the gas discharge | release unit in this invention. It is a front view which illustrates 8th embodiment of the gas discharge | release unit in this invention, (a) is a front view in normal time, (b) is a front view of the state which act | operated at the time of flooding. It is a front view which illustrates 9th embodiment of the gas discharge | release unit in this invention, (a) is a front view in normal time, (b) is a front view of the state which act | operated at the time of water immersion. It is a front view which illustrates the further another example of the gas discharge | release unit in this invention, (a) is a front view in normal time of 5th embodiment, (b) is a front view in normal time of 6th embodiment. (C) is the front view in the normal time of 10th Embodiment, (d) is the front view in the normal time of 11th Embodiment. It is a figure which illustrates 12th embodiment of the gas discharge | release unit in this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Closure, 2a, 2b ... Optical cable, 20a, 20b ... Optical fiber, 200a, 200b ... Cable cross section, 3 ... Gas discharge unit, 31, 51, 61, 71, 81. ..Gas supply ports, 310, 510, 610, 710, 811... Movable pieces for opening and closing, 312, 512, 612, 712, 812 ... springs for opening, 32 movement restricting members, 33. 34, second opening spring, 35, pipe, 36, cylinder, 4 ... water immersion sensor, 62 ... sealing member, 810 ... on-off valve

Claims (14)

A closure,
The closure sleeve (10) into which the cable is drawn includes an opening / closing valve provided in the gas supply port (31) for discharging the compressed and filled gas in the gas cylinder (36). The opening / closing valve is opened from the closed state. A valve opening unit for releasing the gas in the gas cylinder from the gas supply port by switching to a state is provided;
The gas is any one of dry air, nitrogen gas, carbon dioxide (CO ₂ ), and a mixed gas of two or more thereof.
The valve opening unit directly connects the open / close valve and the open / close switching movable piece (310) protruding from the open / close valve or the protrusion of the open / close movable piece protruding from the open / close valve. An opening for moving the opening / closing movable piece from a closed position for closing the opening / closing valve to an opening position for opening the opening / closing valve by urging via an urging force transmitting member that is in contact with or connected to the portion. And a movement restricting member (32) for preventing movement of the opening / closing movable piece or the biasing force transmitting member by the biasing force of the opening spring against the biasing force of the opening spring. Comprising
The movement restricting member is made of a material that collapses or dissolves when contacted with water, and the opening spring is provided with the protrusion of the movable piece for opening and closing, or the protrusion is directly or via the biasing force transmission member. The opening spring of the opening / closing movable piece or the biasing force transmitting member is provided in one or a plurality of positions fixed to the closure sleeve in contact with a component of the biasing mechanism biased by the biasing force of The movement by the urging force of
The valve opening unit moves the opening / closing movable piece of the opening / closing valve from the closed position to the opened position by the urging force of the opening spring by the movement restricting member collapsing or dissolving due to contact with water. A closure that discharges gas in the gas cylinder from the gas supply port. A closure,
The closure sleeve (10) into which the cable is drawn includes an opening / closing valve provided in the gas supply port (31, 51) for discharging the compressed and filled gas in the gas cylinder (36). A valve opening unit for releasing the gas in the gas cylinder from the gas supply port by switching from the open state to the open state,
The gas is any one of dry air, nitrogen gas, carbon dioxide (CO ₂ ), and a mixed gas of two or more thereof.
The open / close valve includes an open / close switching movable piece (310, 510) incorporated in the open / close valve as a variable projection amount, and an open / close valve that urges the open / close movable piece to protrude from the open / close valve. A spring (312),
The valve opening unit includes the opening / closing valve, an abutting member (33) abutting on the protruding portion of the opening / closing movable piece, and a movement restricting member (32) made of a material that collapses or dissolves by contact with water. ), And one or a plurality of the movement regulating members provided in contact with one or both of the on-off valve and the abutting member are configured to resist the biasing force of the opening spring and the on-off valve and the An increase in the distance between the contact member is prevented, and the state where the opening / closing movable piece is pushed into the opening / closing valve is maintained,
When the movement restricting member is collapsed or dissolved by contact with water, the opening / closing movable piece is protruded from the opening / closing valve by the biasing force of the opening spring from the closed position where the opening / closing movable piece is pushed into the opening / closing valve, The closure is moved to an open position for opening the on-off valve, and the gas in the gas cylinder is discharged from the gas supply port. Further, the valve opening unit is provided with a separation spring that biases one or both of the on-off valve and the contact member to separate the on-off valve and the contact member,
The closure according to claim 2, wherein the movement restricting member prevents an increase in a distance between the on-off valve and the abutting member against an urging force of the separation spring. A closure,
The closure sleeve (10) into which the cable is drawn includes an opening / closing valve provided in a gas supply port (61, 71) for discharging the compressed and filled gas in the gas cylinder (36). A valve opening unit for releasing the gas in the gas cylinder from the gas supply port by switching from the open state to the open state,
The gas is any one of dry air, nitrogen gas, carbon dioxide (CO ₂ ), and a mixed gas of two or more thereof.
The opening / closing valve includes an opening / closing movable piece (610, 710) for switching between opening and closing that is incorporated in the opening / closing valve as a variable amount of protrusion.
The valve opening unit presses the projecting portion of the open / close movable piece and the open / close valve in which the open / close movable piece is disposed at a closed position where the projecting dimension from the open / close valve is larger than the open position. A contact member (33) for pushing the open / close movable piece into the open / close valve, and an opening for biasing one or both of the open / close valve and the contact member to bring the open / close valve and the contact member closer to each other The spring (34) is made of a material that collapses or dissolves when contacted with water, and is provided in contact with one or both of the on-off valve and the abutting member, and the opening and closing against the urging force of the opening spring. One or a plurality of movement restricting members (32) for preventing the approach between the valve and the contact member,
When the movement restricting member is collapsed or dissolved by contact with water, the opening / closing movable piece pressed against the contact member by the biasing force of the opening spring is pushed into the opening / closing valve from the closed position. The closure is moved to an open position for opening the on-off valve, and the gas in the gas cylinder is discharged from the gas supply port.   The movable piece for opening and closing is a stem that is incorporated in the housing of the on-off valve and is urged so as to protrude from the housing by a protruding spring provided on the on-off valve, and protrudes from the on-off valve The closure according to any one of claims 2 to 4, further comprising a gas discharge hole opened in the portion.   One of the on-off valve and the abutting member is fixed in the closure sleeve, and the movement restricting member prevents the other of the on-off valve and the abutting member from moving against the biasing force of the opening spring. The closure according to any one of claims 2 to 5, wherein the closure is regulated.   The closure according to any one of claims 1 to 6, wherein the valve opening unit is arranged at the bottom of the closure. A closure,
In the closure sleeve (10) into which the cable is drawn, there is provided a gas supply port (31) for releasing the compressed and filled gas in the gas cylinder (36),
The gas is any one of dry air, nitrogen gas, carbon dioxide (CO ₂ ), and a mixed gas of two or more thereof.
The said gas supply port is sealed by the sealing member (62) which consists of a material which the opening part collapse | disintegrates or melt | dissolves by contact with water.   The closure according to claim 8, wherein the gas supply port is provided at a bottom portion in the closure.   The said gas cylinder is installed in the outer side of the said closure sleeve, The closure as described in any one of Claims 1-9 characterized by the above-mentioned.   The closure according to any one of claims 1 to 10, wherein the movement restricting member or the sealing member is made of rock salt or quicklime.   The closure according to any one of claims 1 to 12, wherein a filling amount of the gas is an amount capable of maintaining a pressure in the closure at a temperature higher than atmospheric pressure by at least 0.65 atm.   The closure according to any one of claims 1 to 12, further comprising an inundation detection sensor (4) provided therein.   The closure according to any one of claims 1 to 13, wherein gas permeation suppressing means is provided on an exposed cross section of the cable drawn into the inside.

Images