JP6929401B1 - Closures and methods for making closures - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a closure having high watertightness. A closure 100 that houses a connection portion 20 of communication cables L1 and L2, and the inside of the closure 100 is filled with an insulating admixture 5. [Selection diagram] Fig. 1

Description

The present invention relates to a closure technique for accommodating a connection portion of a communication cable.

The connection part of the communication cable arranged in the underground equipment is protected by being surrounded by a highly airtight closure. Furthermore, by supplying gas (dry air) from the communication building to the underground cable and closure to increase the internal pressure, water is prevented from entering the cable and closure even when the manhole or pipeline is submerged.

For underground cable maintenance, a pressure transmitter will be installed inside the closure to monitor the gas pressure. When a gas leak is detected, the maintenance worker goes to the place where the gas leak is suspected and repairs the gas leak.

Japanese Patent No. 6620216

Due to aging of underground cable equipment, gas leaks from closures may occur. When the internal pressure of the underground cable and closure drops due to gas leakage, water infiltrates from the leaked part, causing insulation failure and leading to communication interruption. When a gas leak is detected, it is necessary to go to the site to repair the closure, which causes a sudden operation and a heavy burden on the maintenance worker. In the future, in order to promote the leveling and reduction of maintenance operations, it is desirable to take preventive maintenance measures centered on closures with a high risk of gas leaks.

The present invention has been made in view of the above, and an object of the present invention is to provide a closure having high watertightness.

The closure according to the present invention is a closure for accommodating a connection portion of a communication cable, and a nozzle with a valve for filling the inside of the closure with an insulating admixture and filling the inside of the closure with the insulating admixture from the outside. The gist is to prepare.

The method for manufacturing a closure according to the present invention is a method for manufacturing a closure for accommodating a connection portion of a communication cable, which comprises a step of attaching a valved nozzle for filling the closure with an insulating admixture and a valved nozzle. The gist is to have a step of press-fitting the insulating admixture through the process.

According to the present invention, it is possible to provide a closure having high watertightness.

It is a perspective view which shows typically the appearance of the closure which concerns on embodiment of this invention. It is a figure which shows typically the cross section along the line AA shown in FIG. It is sectional drawing which shows typically the process of attaching the nozzle with a valve shown in FIG. It is a figure which shows typically the process of press-fitting an insulating admixture into the closure shown in FIG. It is a perspective view which shows the modification 1 of the nozzle with a valve schematically. It is a figure which shows typically the cross section of the attachment part of the nozzle with a valve of the modification 1. It is a perspective view which shows typically the appearance of the modification 2 of the closure shown in FIG. It is a flowchart which shows the procedure of manufacturing the closure shown in FIG. It is sectional drawing which shows typically the main steps of the method of filling an insulating admixture by its own weight.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same reference numerals are given to the same objects in a plurality of drawings, and the description is not repeated.

FIG. 1 is a perspective view schematically showing the appearance of a closure according to an embodiment of the present invention. The closure 100 shown in FIG. 1 houses a connection portion between the communication cable L1 and the cable L2, and is arranged in a manhole, for example. The cables L1 and L2 expose the core wires 11 and 12 from which the covering member has been removed, and their respective tip portions are connected by a connecting portion 20.

When the cables L1 and L2 are metal cables, the connection portion 20 is connected by, for example, a PAT connector. When the cables L1 and L2 are optical cables, they are connected by an MT connector.

The closure 100 shown in FIG. 1 includes a cylindrical sleeve body 1, an end face plate 2 that grips cables L1 and L2 at both ends of the closure 100, a stainless band 3 that presses and fixes the closure 100 from the side surface, and a valve. The closure 100 is provided with a nozzle 4 and the inside of the closure 100 is filled with an insulating admixture 5.

The sleeve body 1 is configured by combining two upper and lower semi-cylindrical sleeve bodies 1a and 1b. A sleeve gasket (not shown) is arranged at the joint of the sleeve bodies 1a and 1b.

The end face plate 2 is provided with an opening 2c for passing the cables L1 and L2, and is configured by combining two upper and lower semicircular end face plates 2a and 2b. The end face plate 2 is arbitrarily selected and used according to the number and size of the cables L1 and L2 to be passed through. For example, when the cable is branched into two at the connection portion, an end face plate having two openings is used on the branch side.

The stainless band 3 is wound around the outer circumference of the sleeve bodies 1a and 1b that sandwich the end face plates 2a and 2b holding the cables L1 and L2 from above and below, and is tightened with screws 3a. The stainless band 3 is provided at, for example, both ends of the cables L1 and L2 in the extending direction, and is fixed by pressing the outer circumference of the sleeve body 1.

The valved nozzle 4 is attached from the outside of the sleeve body 1 through the sleeve body 1. For example, an adhesive is applied and sealed between the valve-equipped nozzle 4 and the sleeve body 1.

After the valved nozzle 4 is attached, gas is supplied from the communication building via the cable L1, so that the pressure inside the closure 100 becomes higher than the atmospheric pressure. In that state, the closure 100 is filled with the insulating admixture 5 from the outside. The insulating admixture 5 is press-fitted through the valved nozzle 4.

The insulating admixture 5 is a so-called resin. For example, a SUD compound or the like in which two liquids are mixed and solidified after a lapse of a certain period of time can be used.

When the closure 100 is filled with the insulating admixture 5, the periphery of the connecting portion 20 of the cables L1 and L2 is also covered with the insulating admixture 5. Therefore, the connection portion 20 of the cables L1 and L2 is not exposed to water.

As described above, the closure 100 according to the present embodiment is a closure for accommodating the connection portions 20 of the cables L1 and L2, and includes a nozzle 4 with a valve for filling the closure 100 with the insulating admixture 5 from the outside. , The closure 100 is filled with an insulating admixture 5. Thereby, it is possible to provide a closure having high watertightness.

FIG. 2 is a diagram schematically showing a cross section taken along the line AA shown in FIG. In FIG. 2, the cables L1 and L2 are shown in a side view.

As shown in FIG. 2, the valved nozzle 4 penetrates a part of the sleeve body 1 and is attached from the outside. For example, the valved nozzle 4 and the sleeve body 1 are bonded and sealed with an adhesive 6.

A blade is formed at the tip of the attachment port 4a of the valved nozzle 4. Further, a check valve 4c is provided inside the flange of the pressure inlet 4b of the valved nozzle 4 so that pressure is not ejected from the inside to the outside of the closure 100. The check valve 4c shown in FIG. 2 shows an example of a check valve in which a flat plate-shaped valve opens and closes, but it may be a ball valve.

Next, a method of attaching the valve-equipped nozzle 4 will be described.

(Installation of nozzle with valve)
FIG. 3 is a cross-sectional view schematically showing a general process of attaching the valved nozzle 4 to the sleeve body 1. FIG. 3A shows the sleeve body 1 before mounting the valved nozzle 4. FIG. 3B shows a state in which a temporary hole is formed in the sleeve body 1. FIG. 3C is a diagram showing a state after the nozzle 4 with a valve is attached.

As shown in FIG. 3A, the sleeve body 1 is made of, for example, polypropylene (PP) having a predetermined thickness. The inside of the closure 100 before mounting the valved nozzle 4 is filled with gas (not shown) supplied from the communication building via the cable L1.

In that state, a temporary hole 1c is made on the surface of the sleeve body 1 at the position where the valved nozzle 4 is attached. As shown in FIG. 3B, the temporary hole 1c is drilled (not shown) using a blade-shaped jig in consideration of the thickness of the sleeve body 1.

Next, the mounting port 4a is inserted into the temporary hole 1c, and the valved nozzle 4 is pushed in while rotating. The blade at the tip of the mounting port 4a cuts off a part of the thinned sleeve body 1 at the temporary hole 1c. Then, the valved nozzle 4 abuts the flange of the mounting port 4a against the surface of the sleeve body 1 and projects the blade into the closure 100. After that, the valved nozzle 4 is fixed by applying an adhesive 6 between the outside of the flange of the mounting port 4a and the surface of the sleeve body 1.

The above steps can be performed while maintaining the airtightness inside the closure. Therefore, the nozzle 4 with a valve can be attached without the risk of flooding in the closure 100.

Next, a method of press-fitting the insulating admixture 5 will be described.

(Press-fitting of insulating admixture)
FIG. 4 is a diagram schematically showing a step of press-fitting the insulating admixture 5 into the closure 100. As shown in FIG. 4, in this step, the valved nozzle 4 of the closure 100 and the injection pump container 30 are connected by an injection hose 31.

A predetermined amount of the insulating admixture 5 is preliminarily placed in the injection pump container 30. The predetermined amount is, for example, an amount that fills the inside of one closure 100 with the insulating admixture 5.

In that state, the internal pressure of the injection pump container 30 is made higher than the internal pressure of the closure 100 with the compressed air α. Then, the insulating admixture 5 in the injection pump container 30 moves into the closure 100. As a result, the closure 100 is filled with the insulating admixture 5.

By providing the pressure difference in this way, the insulating admixture 5 can be injected into the closure 100.

(Modification example 1)
FIG. 5 is a perspective view schematically showing a modified example of the nozzle with a valve. The valved nozzle 42 shown in FIG. 5 is mounted on the stainless band 32. The stainless band 32 differs from the stainless band 3 (FIG. 1) in that it includes a washer portion 32a for attaching the valved nozzle 42.

FIG. 6 is a diagram schematically showing a cross section of a mounting portion of the nozzle 42 with a valve. As shown in FIG. 6, a thread is cut on the outer circumference of the mounting port 42a of the nozzle 42 with a valve. Further, the washer portion 32a is provided with a through hole 32b into which the attachment port 42a of the valved nozzle 42 is inserted, and the inside of the through hole 32b is threaded.

The valved nozzle 42 and the stainless band 32 are fixed by fitting their respective screws. Therefore, the nozzle 42 with a valve can be easily attached to the sleeve body 1 in the same manner as tightening a screw. That is, the mounting direction of the valved nozzle 42 (the method perpendicular to the surface of the sleeve body 1) is determined by the fitting of the screws. Then, if the outer circumference of the pressure inlet 4b of the valved nozzle 42 is formed in a bolt shape (FIG. 1), the valved nozzle 42 can be easily attached with a spanner or the like.

A rubber packing (not shown) may be provided between the flange of the mounting port 42a and the washer portion 32a. The stainless band 32 may be made of another metal having a certain degree of elasticity.

As described above, the closure shown in FIG. 5 includes a metal band 32 that presses and fixes the outer circumference of the closure, and the nozzle 42 with a valve is fixed to the metal band 32. This makes it possible to facilitate the work of attaching the nozzle with valve to the sleeve body 1.

(Modification 2)
FIG. 7 is a perspective view schematically showing the appearance of the closure of the modified example 2. The closure 200 shown in FIG. 7 differs from the closure 100 (FIG. 1) in that it includes a relief valve 7.

The relief valve 7 releases the gas in the closure 200 to the outside. The relief valve 7 is a relief valve that releases a high pressure to the outside when the internal pressure of the closure 100 becomes higher than the pressure that the closure 100 can withstand.

By the action of the relief valve 7, the insulating admixture 5 can be safely injected at a high pressure (compressed air α). In addition, the insulating admixture 5 can be injected quickly. On the other hand, without the relief valve 7, high pressure may be applied to the closure 100 and the cable and cause it to burst.

As described above, the closure 200 of the second modification includes a relief valve 7 that discharges the gas in the closure to the outside. As a result, the press-fitting time of the insulating admixture 5 can be shortened.

(How to make closures)
FIG. 8 is a flowchart showing a procedure for manufacturing the closure 100.

To make the closure 100, first the closure is formed (step S1). The closure 100 is formed by inserting cables into the end face plates 2 to connect the cables to each other, sandwiching the end face plates 2 with the sleeve main body 1, and pressing the outer circumferences of both ends of the sleeve main body 1 with stainless bands 3 ( Figure 1).

Next, the valved nozzle 4 is attached to the sleeve body 1 (step S2). The nozzle 4 with a valve may be attached directly to the sleeve body 1 or may be attached using a stainless band 32.

Next, the insulating admixture 5 is press-fitted through the attached nozzle 4 with a valve (step S3). Press-fitting is performed by connecting the nozzle 4 with a valve and the injection pump container 30 with an injection hose 31 and using compressed air α (FIG. 5).

It is also conceivable that the insulating admixture 5 is press-fitted into the already constructed closure later. In this case, the process of forming the closure has already been completed.

That is, the method for manufacturing a closure according to the present embodiment including the already constructed closure is a method for manufacturing a closure for accommodating a cable connection portion, and is a step of attaching a nozzle for filling the closure 100 with an insulating admixture 5. (Step S2) and a step (step S3) of press-fitting the insulating admixture 5 via the valve-equipped nozzle 4. This makes it possible to produce a closure with high watertightness.

As described above, the closure 100 according to the present embodiment provides a highly watertight closure. Further, since the nozzle 4 with a valve is attached while the pressure in the closure is higher than the atmospheric pressure, there is no risk of flooding. Further, in the modified closure 200, since the relief valve 7 releases the high-pressure gas inside to the outside, the effect of shortening the press-fitting time of the insulating admixture 5 can be obtained.

The highly watertight closure 100 of the present embodiment can be created without providing the valved nozzle 4. In that case, two holes 40 and 41 are made in the sleeve body 1, and the insulating admixture 5 is filled from one hole 40 by its own weight.

FIG. 9 is a cross-sectional view schematically showing a step of filling the insulating admixture 5 by its own weight. FIG. 9A shows a state in which two holes 40 and 41 are formed in the sleeve body 1. The holes 40 and 41 are made directly above the sleeve body 1.

Further, as shown in FIG. 9A, the tilting of the sleeve body 1 facilitates the exhaust of the air inside the closure 100 from the hole 41. By exhausting the air inside the closure 100, the insulating admixture 5 can be distributed to every corner.

In FIG. 9B, a large funnel 50 is inserted into the hole 40 on the lower side of the inclination, and a small funnel 51 is inserted into the hole 41 on the upper side of the inclination. It shows a state in which the injection is stopped with the insulating admixture 5 slightly overflowing from the water. After the insulating admixture 5 has been injected, the position of the sleeve body 1 is leveled and the insulating admixture 5 is distributed inside (this state is not shown).

The funnels 50 and 51 are fixed by pushing them into the holes 40 and 41 with, for example, butyl rubber (not shown) wrapped around the tip portion. Alternatively, it may be fixed with an adhesive.

FIG. 9C shows a state in which the posture of the sleeve body 1 is horizontal and the funnels 50 and 51 are cut off after the insulating admixture 5 is solidified.

In this way, the insulating admixture 5 can be filled inside the closure 100 without providing the valved nozzle 4. In short, the closure 100 according to the present embodiment is a closure that houses the connection portion of the communication cable, and the inside of the closure 100 is filled with the insulating admixture 5. This makes it possible to produce a closure with high watertightness.

The relief valve 7 may be fixed to the stainless band 32 in the same manner as the nozzle with valve 42. By doing so, the relief valve 7 can be easily attached to the sleeve body 1.

Further, although the example in which one stainless band 3 of the closure 100 is provided at both ends of the sleeve body 1 has been described, the present invention is not limited to this example. The stainless band 3 may include three or more. Further, although an example of connecting the cables L1 and L2 is shown, the present invention can be applied as it is to a closure having another configuration, for example, a closure in which the cable L1 is branched into the cables L2 and L3. Further, the present invention can be applied to both closures for metal cables and optical cables, and the same effects can be obtained.

As described above, the present invention includes various embodiments not described here. Therefore, the technical scope of the present invention is defined only by the matters specifying the invention relating to the reasonable claims from the above description.

L1, L2: Cable 1a, 1b: Sleeve body (1)
2,2a, 2b: End face plate 3,32: Metal band (stainless steel band)
4,42: Nozzle with valve 5: Insulating admixture 6: Adhesive 7: Relief valve 40, 41: Hole 50: Large funnel 51: Small funnel 100, 200: Closure

Claims (5)

A closure that houses the connection of the communication cable
The inside of the closure is filled with an insulating admixture and
A closure comprising a nozzle with a valve for filling the closure with the insulating admixture from the outside . A metal band for pressing and fixing the outer circumference of the closure is provided.
The closure according to claim 1 , wherein the valved nozzle is fixed to the metal band. The closure according to claim 1 or 2 , further comprising a relief valve that discharges the gas in the closure to the outside. It is a method of making a closure that houses the connection part of the communication cable.
The process of installing a nozzle with a valve to fill the closure with an insulating admixture, and
A method for producing a closure, which comprises a step of press-fitting the insulating admixture through the valved nozzle. The method for producing a closure according to claim 4 , wherein the step of press-fitting the insulating admixture is performed in a state where the internal pressure in the closure is higher than the atmospheric pressure.

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