JPH0321174Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a recovery device for a moisture absorbent added in a cable junction box.

[Technical background of the invention and its problems] Conventionally, when installing a single-core OF cable, a cross-bond grounding method has been adopted in order to limit the sheath voltage induced in the metal sheath.

In this method, as shown in FIG. 2, a cable junction box 3 is used in which the central part of the connecting copper tube 1 is insulated and divided by an insulating tube 2.

However, if the insulating tube 2 of the cable junction box 3 is made of phenolic resin, moisture will permeate through the insulating tube 2 and into the cable junction box 3 during long-term use. This moisture is absorbed into the base of the insulation reinforcing layer 4a of the OF cable 4 inside the cable junction box 3, causing a problem of degrading the insulation properties.

In order to prevent such deterioration of the insulation properties of the insulation reinforcing layer 4a, a moisture absorbent 5 such as a molecular sieve has been conventionally introduced into the cable junction box 3.

By the way, the effective period of such a moisture absorbent 5 is as follows.
Because it is shorter than the service life of OF cables 4 and 4,
It needs to be replaced periodically. Moreover, since this work must be carried out on a large number of cable junction boxes 3 within a narrow tunnel, it is desirable to carry out the work while the cable junction boxes 3 are still filled with oil without disassembling them.

However, even if an attempt is made to drain the oil by opening the oil filler port 3a at the bottom of the existing cable junction box 3, for example, this type of moisture absorbent 5 is in the form of fine particles, and moreover, it adheres to the wall surface of the cable junction box 3. There was a problem that it was not easy to collect because it was easy to remove.

Another option is to drain the oil over a long period of time while injecting insulating oil to completely remove the moisture absorbent, but even with this method, it is difficult to judge when the work is finished, and the reliability of the work is affected. There was a problem with missing parts.

[Effects of the invention] The present invention has been made to solve these conventional difficulties, and it is possible to remove the moisture absorbent put into the cable junction box 3 almost completely without disassembling the cable junction box 3. can be easily recovered,
Moreover, it is an attempt to provide a device that allows one to easily know when the collection has ended.

[Summary of the invention] That is, the moisture absorbent recovery device of the present invention includes a cable connection box, a transparent sealed container having a moisture absorbent sedimentation part at the bottom and a scale on the outer periphery of the sedimentation part, and a circulation pump. Connected by piping to form a circulation path,
The present invention is characterized in that the insulating oil filled in the cable connection box is circulated through this circulation path, thereby causing the moisture absorbent in the cable connection box to settle into the transparent closed container.

[Embodiment of the invention] The details of the invention will be described below with reference to an embodiment shown in FIG. In FIG. 1, parts common to those in FIG. 2 are given the same reference numerals and redundant explanations will be omitted.

In the figure, reference numeral 6 denotes a transparent sealed container in the shape of a graduated cylinder, and a scale 6a is provided on the outer periphery in a vertical direction from the bottom. 7 is a vacuum container having a vacuum pump 8, and 9 is a circulation pump.

The upper oil supply port 3b of the cable junction box 3 of the single-core OF cable and the transparent sealed container 6 are connected by a pipe 10a, and the transparent sealed container 6 and the vacuum container 7 are connected by a pipe 10a.
It is connected by a separate piping 10b. Further, the bottom of the vacuum container 7 is connected to the suction port of the circulation pump 9 by a pipe 10c, and the discharge port of the circulation pump 9 is connected to the lower oil supply port 3a of the cable junction box 3 by a pipe 10d. Reference numeral 11 indicates a flexible tube for suctioning the moisture absorbent inserted from the pipe 10a into the bottom of the cable junction box 3, and reference numeral 12 indicates a filter provided at the end of the pipe 10b to prevent the moisture absorbent 5 from entering the vacuum container 7. It is.

Next, the operation of this embodiment will be explained.

First, when the vacuum pump 8 is driven to reduce the pressure in the vacuum container 7, the insulating oil in the cable connection box 3 is sucked into the vacuum container 7 through the transparent sealed container 6. Once the insulating oil is injected into the vacuum container 7, the circulation pump 9 is driven to cause the insulating oil in the vacuum container 7 to flow back into the cable connection box 3, and the insulating oil in the cable connection box 3 is transferred to the pipe 10a, transparent and sealed. container 6,
The circulation pump 9 is adjusted so that the piping 10b, the vacuum container 7, the piping 10c, the circulation pump 9, and the piping 10d are obtained and circulated.

When the insulating oil in the cable junction box 3 starts circulating, the moisture absorbent 5 in the cable junction box 3 moves into the transparent sealed container 6 together with the insulating oil and gradually settles to the bottom thereof.

In this way, the scale 6a indicates that an amount of moisture absorbent 5 corresponding to the input amount has settled in the transparent sealed container.
When confirmed, the moisture absorbent 5 in the cable junction box 3 has been completely recovered.

After this, each oil filler port 3a, 3 of the cable junction box 3
The work is completed by removing the pipes 10a and 10b from b and putting a new moisture absorbent into the cable junction box 3.

[Effects of the invention] As explained above, according to the moisture absorbent recovery device of the present invention, the moisture absorbent can be transferred to the external piping system by circulating the insulating oil in the cable junction box to the external piping system. Since it is sent out and allowed to settle in a transparent sealed container, it is possible to easily recover the entire amount of moisture absorbent, and it is also easy to know whether the entire amount has been collected just by looking at the scale on the transparent sealed container. be able to.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an embodiment of the present invention, and FIG. 2 is a sectional view schematically showing a cable junction box for a single-core OF cable. 1... Connecting copper pipe, 2... Insulating tube, 3... Cable connection box, 4... OF cable, 4a... Insulating reinforcing layer, 5... Moisture absorbent, 6... Transparent sealed container, 7...
...Vacuum container, 8...Vacuum pump, 9...Circulation pump, 10a-10b...Piping.

Claims (1)

[Scope of utility model registration request] A cable connection box, a transparent sealed container having a desiccant settling part at the bottom and a scale on the outer periphery of the settling part, and a circulation pump are connected by piping to form a circulation path, and this circulation path has the above-mentioned A moisture absorbent added in a cable connection box, characterized in that the moisture absorbent in the cable connection box is caused to settle in the transparent sealed container by circulating insulating oil filled in the cable connection box. recovery equipment.