JPH0127390Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a connection part of a water-shielding cable in which a metal protective tube is fitted over the connection part.

[Technical background of the invention and its problems] It is generally known that when plastic sheathed cables are installed outdoors, moisture gradually enters the cable core through the sheath, deteriorating the electrical characteristics of the cable. ing. Particularly in plastic-insulated high-voltage power cables such as cross-linked polyethylene, intruded moisture interacts with the electric field to generate water trees like bow trees, which can cause dielectric breakdown.

In order to solve this problem, a metal tape made of aluminum or lead laminated with a plastic film such as polyethylene or polyester on one or both sides is placed vertically on the cable core, and the overlapping part is heat-fused. Water-shielding cables with a water layer have been developed in the past.

At the connection part of such water-shielded cables,
In order to have high water-shielding properties similar to cables, a metal protective tube is fitted over the connection part, and the end part is fixed watertightly on the sheath.

By the way, in connection parts of such water-shielded cables, it is advantageous for the inner diameter of both ends of the metal protection tube to be as close to the cable sheath as possible in order to ensure watertightness. It is virtually impossible to prepare metal protection tubes with different diameters to suit all cables, so a common metal protection tube with a larger inner diameter at both ends is used for several types of cables with different outer diameters. The reality is that . The outside diameter of the cable sheath is matched to the inside diameter of both ends of the metal protection tube by wrapping plastic tape or the like to an appropriate thickness on the cable sheath and heat-sealing it to form a watertight seat layer. It was

However, with such a watertight floor layer, there was a problem that the watertightness of this part was insufficient because there was a large gap between the inner diameter of both ends of the metal protection tube and the outer diameter of the cable sheath. .

[Purpose of the invention] The present invention was made to solve these problems, and the purpose is to provide a water-shielding cable connection part that has a complete water-shielding function and is easy to manufacture. do.

[Summary of the invention] In other words, the connection part of the water-shielded cable of the present invention is a water-shielded cable in which a metal protection tube is fitted on the outside of the connection part insulator, and a watertight seal is provided between the protection tube and the cable sheath. At the connection point, a watertight seat layer is provided by winding and heat-sealing a metal laminate tape on the sheath at each end of the connected cable, and multiple metal layers are laminated on this watertight seat layer. The constructed annular metal spacer is fixed in a watertight manner, and a metal connecting tube is fitted over both ends of the metal protection tube and the metal spacer, respectively, to seal the overlapping portion watertightly. It is characterized by the fact that it can be worn and worn.

[Embodiment of the invention] An embodiment of the invention shown in the drawings will be described below.

The drawing is a vertical cross-sectional view of one embodiment of the connection part of the water-shielding cable of the present invention, and shows one of the connected water-shielding cables, and the other water-shielding cable is also similar although not shown. It has the structure of

In the figure, reference numeral 1 indicates one of a pair of water-shielded cables that are connected by stripping the ends, and there is a spindle-shaped connection portion on the connection portion (not shown) of the conductor 2 of this water-shielded cable 1. An insulator 3 is provided, and a metal protective tube 4 is fitted on the outside of the insulator 3.

A gap is formed between the inner surface of both ends of the metal protective tube 4 and the sheath 5, and this gap is sealed by a watertight seat layer 6 and an annular metal spacer 7.

The watertight seat floor layer 6 is formed by, for example, wrapping a plastic laminated metal tape made by laminating a metal tape on one side of a plastic film around the sheath 5 with the plastic layer inside, and heating and fusing the overlapped portion. .

Further, the annular metal spacer 7 can be made by stacking an appropriate number of thin metal spacers 7 and fixing the metal spacers 7 by a method such as soldering, or by using a metal tape with an appropriate inner and outer diameter. It is constructed of layers that are laminated into an annular shape and fixed watertightly by a method such as winding and soldering, and the thickness is adjusted depending on the size of the gap and is soldered onto the watertight seat floor layer 6.

Further, a metal connecting tube 8 is inserted and fitted across the metal spacer 7 and the end of the metal protection tube 4,
Both ends of the metal connecting tube 8 are fixed onto the metal spacer 7 and the metal protective tube 4 by lead work or a solder layer 9. Furthermore, a winding layer 10 of waterproof tape is provided on this, spanning from the metal protective tube 4 to the sheath 5.

Note that a copper pipe or a lead pipe can be used as the metal connecting pipe 8, but especially when a lead pipe is used, the outer diameter of the end can be easily adjusted by caulking. It has the advantage of being able to handle differences in thickness to a certain extent.

In the embodiment configured as described above, the annular metal spacer is watertightly attached via a watertight floor layer made by winding and heat-sealing a metal laminate tape on the sheath at each end of the cable. Since it is fixed, the metal spacer can be fixed watertightly on the sheath even if the outer diameter of the sheath varies somewhat. Further, since the entire connecting portion is covered with the metal protective tube 4, the metal connecting tube 8 made of copper or lead, the metal spacer 7, and the watertight floor layer 6, a sufficient water-shielding effect can be obtained. In particular, when these joints or overlapping parts are connected by a method using metal joining materials such as lead work or soldering, they are completely sealed watertight, so no water can enter or penetrate from the outside. In addition, since the metal connecting pipe 8, the metal spacer 7, and the watertight seat layer 6 can be made to have the same potential, for example, by electrically connecting the watertight seat layer 6 to the water shielding layer and grounding it, a metal connection can be made. It is possible to prevent an induced potential from occurring in the tube 8.

[Effects of the invention] As explained above, the connection portion of the water-shielding cable of the present invention has excellent water-shielding properties.

[Brief explanation of the drawing]

The drawing is a longitudinal sectional view of an embodiment of the present invention. 1...Waterproof cable, 4...Metal protection tube, 5
... sheath, 6 ... watertight floor layer, 7 ... metal spacer, 8 ... metal connecting pipe, 10 ... waterproof tape winding layer.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A connection at a connection part of a water-shielding cable, which is formed by fitting a metal protection pipe on the outside of the connection part insulator and applying a watertight seal between the protection pipe and the cable sheath. A watertight seat layer is formed by winding and heat-sealing a metal laminate tape on the sheath at each end of the cable. A metal spacer is fixed in a watertight manner, and a metal connecting tube is fitted over both ends of the metal protection tube and the metal spacer, respectively, and the overlapping portions are sealed in a watertight manner. Features a water-shielding cable connection. (2) The connection portion of the water-shielding cable according to claim 1, wherein the water-shielding cable is a cable having a water-shielding layer made of plastic laminated metal tape on the outer periphery of the cable core. (3) The connection portion of the water-shielding cable according to claim 1 or 2 of the utility model registration claim, wherein the sealing between both ends of the metal connecting pipe and the metal spacer is performed by lead work or soldering.