JPS6053523B2 - Polyethylene cable sheath connection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for connecting polyethylene sheathed communication cables installed underground, such as in a manhole.

In recent years, polyethylene-sheathed cables have been widely used as outdoor communication cables instead of lead-sheathed cables because they have excellent insulation properties, are lightweight, and are inexpensive.

This polyethylene-sheathed cable is then laid underground and connected within a manhole to form an underground cable line. On the other hand, with the adoption of the PCM communication method, it is necessary to extract a desired core wire at a cable connection point and install a repeater.

Conventional methods for connecting polyethylene-sheathed cables include heat-shrink tube methods, compound injection methods, and epoxy putty methods, but all of them involve solidifying organic materials to cover the core wire connections. There are difficulties in pulling out the guard wire and maintaining and inspecting the core wire connection section.

Therefore, the auxiliary lead pipe method is being adopted for the connection portions of polyethylene cables where repeaters are planned to be installed. This auxiliary lead pipe method involves inserting and covering the outer periphery of the core wire connection with a main lead pipe, and installing an auxiliary lead pipe that is smaller in diameter and shorter than the main lead pipe at the end of each polyethylene sheathed cable to be connected. In this method, both ends of the main lead pipe and each auxiliary lead pipe are heated and fused together (this process of fusing lead in this way is called lead work) to seal them. This auxiliary lead pipe method involves cutting the body of the main lead pipe lengthwise.
Not only is it easy to inspect the wire connection status and pull out the core wire, but there is also an advantage that the cut portion of the main lead pipe can be easily sealed by a plumber. This conventional auxiliary lead pipe method will be explained with reference to FIG.

FIG. 1 is a sectional view of a sheathed connection part, and 1 in the figure is a polyethylene sheathed cable in which a large number of sheathed core wires are covered with a polyethylene sheath 1. The core wire 10 from which the polyethylene jacket 1 at the terminal end of the gate cable 1 has been peeled off is connected to the core wire of another opposing cable (not shown). A self-fusing tape is wound around the end portion to form a tape layer 4. The inner diameter is approximately equal to the outer diameter of cable 1,
Connect the auxiliary lead pipe 3, which has a larger inner diameter on the other end side, to the cable 1 in advance.
The large inner diameter part 31 is loosely fitted into the tape! 41 so that it fits. Shift the main lead pipe 2 that covers the core wire connection part, and insert the constricted end 21 into the large inner diameter part 3.
Glue it to the outer periphery of 1. This bonded portion is made with lead and further soldered with solder 5 to strengthen it. The outer periphery of the auxiliary lead pipe 3 and the polyethylene jacket 11 is wound with self-adhesive tape to form a tape layer 42 to maintain adhesion and airtightness between the auxiliary lead pipe 3 and the polyethylene jacket 11. Furthermore, tape layer 4. The outer periphery of the tape is wrapped with adhesive aluminum tape 6 to block ultraviolet rays and prevent deterioration of the self-bonding tape. In this way, the auxiliary lead pipe and polyethylene are bonded together using self-adhesive tape since there is no adhesive that can be used to bond them directly.

However, in the conventional auxiliary lead pipe method, maintaining airtightness between the auxiliary lead pipe and the polyethylene jacket depends on the degree of adhesion of the self-fusing tape.

Therefore, there are problems in that the self-fusing tape deteriorates over many years, resulting in a loss of airtightness, and water or the like penetrates into the polyethylene cable, causing damage. In addition, when winding self-fusing tape, in addition to the thickness of the winding layer, it is necessary to stretch the outer peripheral surface of the polyethylene jacket for a long time, making it difficult to perform step 2 inside a narrow manhole. There is a problem.
SUMMARY OF THE INVENTION In view of the above-mentioned conventional problems, an object of the present invention is to provide a method for connecting polyethylene cable sheathing that has high reliability in airtightness and good workability.

3.The purpose of this is to fasten the ends of each connection part of the polyethylene sheathed cable with copper wire, then fold back the tip of the polyethylene sheath to form a polyethylene terminal layer, and then wrap the terminal layer with adhesive glass tape. Further, the three cable terminal sides of the glass tape layer are wound with copper wire, the remaining part is wrapped with sealing tape, and an auxiliary lead pipe is fitted and crimped onto the sealing tape layer. Then, the wound portion of the copper wire and the outer circumferential surface of the end portion of the auxiliary lead pipe are fixed by soldering, and then the outer circumferential surface of the central portion of the auxiliary lead pipe and the core wire are connected 4. This is achieved by the means of the present invention, in which the end of the main lead pipe covering the connecting part is fitted with lead. The present invention will be specifically described below with reference to illustrated embodiments.

FIG. 2 is a process diagram of the connection work according to an embodiment of the present invention, and the work steps are as follows. 1. Fold back the polyethylene jacket (see A)... Wrap the copper wire 8 around the end of the polyethylene jacket 71 and tighten it, and make several cuts 71 on the end side of the copper wire 8 of the polyethylene jacket 71. ″
The polyethylene jacket 71 is divided and peeled off to make it wet.

Formation of 2 terminal layers (see opening): The separated and peeled outer sheath is folded back at the copper wire 8, and stacked on the upper surface of the polyethylene outer sheath 71 to form the terminal layer 71''.

3. Winding with glass tape (see C): An adhesive glass tape is wound around the outer peripheral surface of the terminal layer 7'' and the boundary between the terminal layer 7 and the polyethylene jacket 7'' to form the glass tape layer 9.

4 Copper wire winding (see 2)...The copper wire 10 is wound several times near the copper wire 8 on the top of the glass tape layer and tightened.

5. Formation of sealing tape layer (see E): A predetermined length of sealing tape is wound from the vicinity of the copper wire 10 to the glass tape layer 9 side to form a trapezoidal sealing tape layer 11.

Note that the core wire 72 of the polyethylene jacketed cable 7 is connected in advance to the opposing core wire. D Auxiliary lead pipe installation (see below)...Before connecting the core wires, fit the predetermined length of the auxiliary lead pipe 12, which has been loosely fitted into the polyethylene sheathed cable 7, into the sealing tape layer 11, and connect both ends. The sealing tape layer 11 is deformed into a trapezoidal shape and fixed.

The end of the auxiliary lead pipe 12 is fixed to the copper wire 10 with a solder pad 13. Ring-shaped recesses 12'' are formed at required locations on the end of the auxiliary lead pipe 12 opposite to the copper wire 10 and on the outer periphery of the cylinder by, for example, rolling or wire wrapping, and the auxiliary lead pipe 12 is covered with a sealing tape layer. 11 to the cable 7. Attaching the main lead pipe (see )... Squeeze the end of the main lead pipe 15, which has been loosely fitted into the core wire connection part in advance, to tightly fit it to the outer periphery of the auxiliary lead pipe 12. (fusing the lead with a torch lamp, etc.) and further strengthening and fixing with solder mound 14.

As shown in the figure, this step is performed after the terminal portions of the opposing polyethylene jacketed cables 70 are connected in steps 1 to 6. With the connection method described above, the terminal layer 7/ of polyethylene is formed, so it is resistant to creeping, and even if the main lead pipe 15 is split vertically for maintenance and inspection at a later date, the connection part will remain intact. It has almost no effect on airtightness and strength.

FIG. 3 shows another embodiment of the present invention in which the core wires are branched.

In the figure, reference numeral 16 denotes a branch line in which a part of the core wire of the polyethylene-sheathed cable 7 is branched at a core wire connection portion and coated with lead.

In this case, the diameter of the main lead pipe 15 is sufficiently larger than the outer diameter of the auxiliary lead pipe 12. Therefore, it is difficult to squeeze the end of the main lead pipe 15, so a head plate 151 made of lead is used, and the outer peripheral surface of the end plate 151 is placed on the end surface of the main lead pipe 15, and the inner peripheral surface is placed on the outer peripheral surface of the auxiliary lead pipe 12. The branch wire 16 is made to pass through the insertion hole of the end plate 151 and led out, and the insertion hole is made with lead and further soldered.
Seal. As explained above, the present invention mechanically crimps the auxiliary lead pipe to the polyethylene sheath and makes it adhere tightly.The work of adhesion is easy and does not require skill, airtightness is maintained for a long period of time, and the auxiliary lead pipe is short. Therefore, this method of connecting polyethylene cables has an excellent practical effect in that the total length of the connecting portion can be shortened.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a conventional connection method, FIG. In the figure, 1 and 7 are polyethylene jacketed cables, 11 and 71 are polyethylene jackets, 12 and 72 are core wires, 3 and 12 are auxiliary lead pipes, 2 and 15 are main lead pipes, 4 is a self-fusing tape layer, and 6 is a Aluminum tape, 8 and 10 are copper wires, 9 is glass tape layer,
11 indicates a sealing tape layer.

Claims (1)

[Claims] 1. In a connection method in which the connecting portion of the core wire of a polyethylene jacketed cable is covered with a lead pipe, the vicinity of the end of the cable is fastened with a copper wire, and then the tip of the polyethylene jacket is folded back to form a polyethylene terminal layer. , the terminal layer is wrapped with adhesive glass tape, the cable terminal side of the glass tape layer is further wrapped with copper wire, the remaining part is wrapped with sealing tape, and an auxiliary lead pipe is fitted into the sealing tape layer.
Crimp the copper wire, then solder and secure the wound portion of the copper wire to the outer peripheral surface of the end of the auxiliary lead pipe, and then attach the main lead pipe that covers the outer peripheral surface of the central part of the auxiliary lead pipe and the connecting part of the core wire. A method for connecting a polyethylene cable sheath, characterized by connecting the end of the cable with lead.