JPH0670438A - Premolded insulator for power cable provided with protective cover in insulation interface part - Google Patents

Abstract

PURPOSE:To keep the quality of a premolded insulator constant by cleansing the premolded insulator in a clean room and by mounting a truncated coneshaped protective cover on the tapered insulation interface part of the insulator coated with a silicone oil and putting the insulator in a sealed container. CONSTITUTION:A premolded insulator (stress cone) 1 formed beforehand by means of rubber or polyethylene, etc., and an interface protective cover 2 formed into a truncated-cone shape coinciding with the external shape of the insulation interface part 1b of the insulator 1 are cleansed in the clean room of a factory. Subsequently, silicone oil is applied to and the protective cover 2 is mounted on the cleansed insulation interface part 1b and the insulator is put and stored in a clean sealed container 3. Then, the insulator together with the sealed container 3 is carried to a field and used there. Therefore, the assembly operation of a connection box can be performed without letting dust and other foreign matters adhere to the insulation interface part 1b. Thus, it is possible to keep the quality of the insulator constant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention of the present application relates to a power cable, especially a crosslinked polyethylene cable (CV cable).
Protects the insulating interface of the premolded insulator from foreign matter and external damage when the rubber or polyethylene premolded insulator used for assembling the connection box is fitted and covered on the insulating layer of the cable. For a protective cover for.

[0002]

2. Description of the Related Art Conventionally, as a connection work in a connection box for a CV cable, a method or a method in which rubber or polyethylene resin containing a cross-linking agent is extruded at a connection site and then cross-linked after the connection end portion of the cable is cross-linked. A method has been adopted in which a molded insulator (pre-molded insulator) is fitted and coated on the insulating layer at the connecting end of the cable. When the latter method, which is easy to install, is adopted, the surface of the pre-molded insulator 1 is cleaned after the shipment inspection at the factory and then sealed in a vinyl bag 8 or the like together with the silica gel 9 and packed. , Transport and take out the pre-molded insulator from the bag immediately before use at the site, inspect and clean it again, apply silicone oil to the interfaces 1a and 1b and the cable insulating layer 4 surface, and assemble and assemble. I was doing.

[0003]

When a premold connection method (prefabricated joint method) using an insulator (premold insulator) that has been preformed has been adopted,
Silicone oil for cleaning the surface of the cable insulator and the inner surface of the joint of the pre-molded insulator, and improving the interfacial electrical insulation property after performing the cable peeling work, that is, the step of removing the sheath portion. Must be applied. And since all of this is done by hand, not only does it take a double labor between the factory and the site, but it also causes variations due to individual differences and causes instability of the interface part. Even if the pre-molded insulation is applied to the end of the cable with the pre-molded insulation, if the interface is exposed for a while until the next work process of mounting the epoxy insulation unit etc. is completed, dust in the air will remain. There is a possibility that foreign matter may be attached or external damage may be caused to deteriorate the electrical insulation characteristics of the interface. Therefore, as a simple preventive measure,
It may be possible to wrap and protect a transparent wrap such as Saran wrap, but when peeling off the wrap, there is a possibility that the wrap's cut pieces will be left behind and the wrap will be cleaned and then wrapped. Since it is impossible, the surface must be cleaned and inspected again after removing the wrap.

[0004]

In order to solve the above problems, the inventor of the present application has found that the insulating interface of a premolded insulator used to form a connecting end in a connecting box such as a CV cable is We have devised an interface protection cover that can be attached to the end of the cable at the construction site with the quality that has been cleaned at the factory without any touch. Then, by covering this with a pre-molded insulator, the assembly work of the junction box can be performed without adhering dust or other foreign matter to the insulating interface portion.

[0005]

As shown in FIGS. 1 and 2, a pre-molded insulator (stress cone) 1 preformed by rubber or polyethylene and a truncated cone conforming to the outer shape of the insulating interface portion 1b of the insulator. After cleaning the interface protection cover 2 formed in the shape in the clean room of the factory, the insulating interface 1
Silicone oil is applied to b, the one with the protective cover 2 attached, the one stored and stored in a clean closed container 3, and the whole closed container is transported to the site for use.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings, and FIGS. 1 to 5 show one embodiment. As you can see in Figure 1,
In the factory, carry a clean pre-molded insulator 1 with an interface protection cover 2 sealed in a dedicated sealed container 3 to the work site, and perform step stripping of the cable end to be connected, After cleaning the surface of the cable insulator 4 and applying silicone oil, immediately take out the premolded insulator 1 from the closed container 3 and immediately press it onto the cable insulator with the protective cover attached as shown in FIG. To be fitted. Next, the epoxy insulation unit 6 for connecting the cable and insulating and shielding the connection part is cleaned, silicone oil is applied to the bonding interface, and then the insulation is performed immediately before fitting to the premolded insulator 1. As shown in FIG. 4, the protective cover 2 adhered to the body is cut and removed, and the fitting and contacting are quickly performed to complete the assembly work of the connecting end of the cable. (See Figure 5)

By performing such an assembling work, the interface portion of the insulator can be installed on-site while being kept clean in the factory where quality control is well done. There is no need to do any special work for. As shown in FIGS. 6 and 7, if a protruding handle 2a is provided at a part of the outer end of the protective cover 2, the premolded insulator 1 can be taken out from the closed container 3 and the protective cover 2 can be removed.
Can be easily removed. Further, if the protective cover 2 is divided into two parts and the joint portion is fixed with an adhesive tape 2b or a perforation is formed, the protective cover is simply peeled off or the perforation is torn. Since it can be easily removed with, there is no risk of scratching the interface during removal, and workability is further improved.

[0008]

In the past, the pre-molded insulator was cleaned and inspected in a factory, then transported in a plastic bag or the like, and then cleaned again at the work site before being assembled. On the other hand, in the present invention, the pre-molded insulator is applied in the clean room in the factory after cleaning and inspection, after applying the silicone oil, with the protective cover attached to the interface part of the insulator. What was stored and stored in a dedicated airtight container was transported to the site for assembly work, so there is a risk of foreign matter adhering to the interface or causing external damage during transport or during assembly at the site. The quality is constant, the assembly work is easy, and the workability and insulation characteristics are improved.

[Brief description of drawings]

FIG. 1 is a closed storage view of a pre-molded insulator having a protective cover according to the present invention.

FIG. 2 is a perspective view of a protective cover according to the first embodiment of the present invention.

FIG. 3 is a sectional view of a premolded insulator using the present invention inserted into a cable end.

FIG. 4 is a sectional view of mounting an epoxy insulation unit on a cable end portion according to the present invention.

FIG. 5 is an assembled partial sectional view of a cable intermediate junction box.

FIG. 6 is a modified view of the protective cover of the present invention.

FIG. 7 is a perspective view of a pre-molded insulator provided with the deformation protection cover of the present invention in a hermetically sealed state.

FIG. 8 is a partial sectional view of a conventional example in which a premolded insulator is stored.

FIG. 9 is a cross-sectional view of insertion of a premolded insulator according to a conventional example to a cable end portion.

[Explanation of symbols]

 1 Pre-molded insulator 2 Interface protection cover 3 Airtight container 4 Cable insulator 5 Cable conductor 6 Epoxy insulation unit

Claims (4)

[Claims] 1. An insulating body preliminarily molded into a stress cone shape using rubber or polyethylene is cleaned in a clean room, and a truncated cone-shaped protective cover is attached to a tapered insulating interface portion coated with silicone oil. Pre-molded insulation for power cables that is installed and stored in a closed container. 2. The premolded insulator according to claim 1, wherein the protective cover is made of polyethylene. 3. The premolded insulator according to claim 1, wherein a handle is formed on a large-diameter end portion of the conical protection cover. 4. The premolded insulator according to claim 1, 2 or 3, wherein the protective cover is a dividable body.