JPH038031Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field of the invention] This invention relates to a temporary oil stop device for OF cables.
In particular, it relates to a temporary oil stopper for OF cables that prevents the occurrence of "wrinkles" and "paper breaks" in insulating paper due to thermal expansion and contraction of cables.

[Technical landscape of invention]

Traditionally, as a temporary oil stopper when forming a connection part of an OF cable, a lead pipe is installed at the connection end of a CF cable whose steps have been stripped to expose the cable core and cable sheath end, and which is straddled over the cable core and cable sheath end. The tube was fitted with a cable, and packing was interposed between the inner surface of the tube, the cable core, and the cable sheath to seal the cable oil-tightly.

In such conventional temporary oil sealing devices, in order to ensure complete oil tightness, the packing is made of a material with excellent oil resistance, such as nitrile gel, which does not dissolve or shrink due to insulating oil. In order to withstand hydraulic pressure, the lead pipes on these packings are bound with binding wire or the like.

[Problems with background technology]

However, such conventional temporary oil stop devices provide sufficient oil tightness and high pressure resistance during temporary oil stop, but on the other hand, the cable thermally expands and contracts after the cable starts being energized, causing damage to the cable core and cable sheath. If a "misalignment" occurs due to a difference in the coefficient of thermal expansion between the cables, wrinkles or paper breaks may occur in the insulating paper on the surface of the cable, which may reduce the insulation properties of the cable.

[Purpose of invention]

This invention was devised to solve these conventional difficulties, and is a temporary OF cable that prevents the deterioration of the insulation properties of the cable due to wrinkles and paper breaks in the insulation paper caused by thermal expansion and contraction of the cable. The purpose is to provide an oil stop device.

[Summary of the idea]

In other words, the OF cable temporary oil stop device of the present invention is
A hard tube is fitted over the connecting end of the OF cable, which has been peeled off to expose the cable core and cable sheath ends, and covers the cable core and cable sheath, and the inner surface of the hard tube and the cable core and cable sheath are connected to each other. In a temporary oil sealing device for an OF cable in which a packing is interposed between the ends to seal each end in an oil-tight manner, at least a portion of the packing is melted or shrinks in the thickness direction due to infiltration of heated insulating oil. It is characterized by being constructed from materials that

[Example of idea]

The details of the present invention will be described below with reference to an embodiment shown in the drawings.

FIG. 1 is a partial vertical sectional view showing an embodiment of the OF cable temporary oil stop device of the present invention.

In the same figure, the connection end 3 of the single-core OF cable, which has been peeled off to expose the cable core 1 and cable aluminum sheath 2, has a sealable air release port 4, and an annular packing inside one end. A lead pipe 6 having a stopper 5 surrounding it is fitted over the cable core 1 and the cable aluminum sheath 2. Packings 7 and 8 are interposed between the inner surface of the lead pipe 6, the cable core 1, and the cable aluminum sheath 2, sandwiching the deaeration port 4, to airtightly seal the open end of the cable aluminum sheath 2. 9 is a binding wire for tightening the packings 7 and 8 from above the lead pipe 6.

In this embodiment, the inner part of the packing 7 disposed on the cable core 1 is made of an oleophilic material a, and the outer part is made of an oil-resistant material b. The lipophilic material a is made of a polymer material that melts or contracts in the thickness direction of the cable when heated insulating oil infiltrates, and the oil-resistant material b is the same as the packing 8 on the cable aluminum sheath 2, for example, made of insulating oil. It is made of nitrile rubber, etc., which is not affected.

Material a has its solubility parameter (Solubilit
y parameter) is close to the solubility parameter of the insulating oil used, and preferably the difference is 1
It is desirable that the insulating oil is within the range and does not adversely affect the properties of the insulating oil even if it dissolves. Examples of such materials include polyethylene, polypropylene,
Examples include olefin polymers such as crosslinked polyethylene and styrene polymers such as polystyrene.

In the temporary oil stopper for OF cables configured in this way, as described below, during cable connection work that requires temporary oil stoppage, the insulating oil in contact with the oleophilic material a is is at room temperature,
Moreover, since the work is relatively short-time, even if the insulating oil infiltrates, it will not melt or deform, and sufficient oil-tightness and pressure resistance will be ensured.

In other words, the OF cable connection part is not shown, but after installing the temporary oil stopper, connect the cable core using the usual method, and fit the connecting copper pipe over the temporary oil stopper and cable core connection part. After fixing both ends of the cable on the cable aluminum sheath 2 in an oil-tight manner using lead work etc., the connecting copper pipe is vacuum filled with insulating oil. During this time, the cable core 1 and the cable are connected by a temporary oil stopper. Aluminum sheath 2
This prevents a large amount of insulating oil from flowing out from the gap between the

After the cable connection is completed and energization is started, the insulating oil is heated by the energization, so
Part or all of the lipophilic material a of the temporary oil stopper dissolves or shrinks in the thickness direction, and the lipophilic material a
A gap G is generated between the cable core 1 and the cable core 1. As a result, the cable core 1 is no longer restrained by the temporary oil stopper, so even if there is a relative shift between the cable core 1 and the cable aluminum sheath 2 due to thermal expansion and contraction of the cable, the insulating paper The occurrence of "wrinkles" and "paper breaks" is prevented.

In other words, in the temporary oil stopper device with the above configuration, sufficient oil tightness and pressure resistance are ensured when connecting cables that require temporary oil stoppage, and once the cable connection is completed and energization is started, the cable is removed by packing 7. The restraint of core 1 is released, and cable core 1 and cable aluminum sheath 2 undergo thermal expansion and contraction of the cable.
Even if there is a relative "shift" in the insulating paper, "wrinkles" or "paper tears" in the insulating paper are prevented from occurring.

Note that after the cable connection part is completed, the cable connection part is covered with the connecting copper pipe, so there is no problem even if the sealing effect of the temporary oil stopper device is lost.

In the above embodiment, an example was explained in which the lipophilic material was arranged in contact with the cable core 1, but the present invention is not limited to this embodiment, and for example, as shown in FIGS. 2 and 3. As shown in Figure 4, it may be placed on the lead pipe 6 side on the cable core 1 or the cable aluminum sheath 2, or the entire packing on the cable core 1 or the cable aluminum sheath 2 may be made of the above material as shown in Figure 4. You can also do this. In FIGS. 2 to 4, parts common to those in FIG. 1 are designated by the same reference numerals.

Furthermore, the shape thereof does not necessarily have to be ring-shaped, but it may be any shape as long as it melts or contracts in the thickness direction by heated insulating oil to reduce or release the binding force of packing.

Furthermore, such a material can also be constructed by winding a tape-like material instead of forming it into a molded body. In this case, since the thickness can be adjusted by increasing or decreasing the number of tape windings, there is no need to manufacture various packings according to the cable size, which is economically advantageous.

[Effect of idea]

As explained above, according to the temporary oil stopper device for OF cables of the present invention, packing for maintaining the oil tightness of the temporary oil stopper device is performed when energizing after the connection is completed.
Since the structure is configured such that the constraint is released, it is possible to prevent the insulation properties of the cable from deteriorating due to the generation of "wrinkles" or "paper breaks" in the insulating paper due to thermal expansion and contraction of the cable.

[Brief explanation of the drawing]

FIG. 1 is a partial vertical cross-sectional view showing one embodiment of the present invention, and FIGS. 2 to 4 are partial vertical cross-sectional views of other embodiments of the present invention. 1... Cable core, 2... Cable aluminum sheath, 3... Connection end of OF cable, 4... Air vent, 6... Lead pipe, 7, 8... Packing, 9...
... Bind wire, a... Lipophilic material, b... Oil-resistant material.

Claims (1)

[Claims for Utility Model Registration] (1) A hard tube is fitted over the connection end of an OF cable that has been peeled off to expose the cable core and cable sheath ends, and this In a temporary oil sealing device for an OF cable, in which packing is interposed between the inner surface of a hard tube and the end portions of the cable core and cable sheath to provide an oil-tight seal, at least a portion of the packing is insulated. OF characterized by being composed of a material that dissolves or shrinks in the thickness direction due to oil infiltration.
Temporary oil stop device for cables. (2) The temporary oil stopper for an OF cable according to claim 1, wherein the solubility parameter of the material that dissolves or shrinks in the thickness direction due to infiltration of insulating oil is similar to the solubility parameter of the insulating oil. (3) The temporary oil stopper for an OF cable according to claim 1 or 2, wherein the material that dissolves or shrinks in the thickness direction due to infiltration with insulating oil is an olefin polymer.