JPH0217884B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a method for manufacturing a cable in which a tape longitudinally spliced cable conductor is heated and insulated.

``Prior art'' Conventionally, cable conductors are cross-linked by continuously extruding insulating coatings such as rubber or plastic.
The cable conductor is fed to an extrusion coating head to be extruded and coated with an uncrosslinked insulation mixture, and this is run into the heating section of the crosslinked pipe to heat and crosslink the uncrosslinked insulation mixture from the outer periphery, but the coating is thick. In this case, it takes a long time to heat the inner layer of the coating sufficiently, so not only is it necessary to install a bridge pipe with a long heating section, but it is also impossible to increase the cable running speed. Ta. In order to quickly heat and crosslink such thick-walled coatings, it is necessary not only to heat the coating from the outer periphery, but also to heat the inner layer of the coating from the cable conductor by heating the cable conductor at the front stage of the head of the extrusion coating machine. was being carried out.

``Problems to be Solved by the Invention'' As mentioned above, in order to heat the cable conductor and completely cross-link it to the innermost layer of the coating, it is necessary to heat the conductor to a high temperature. When heated to a high temperature, the cable conductor running toward the extrusion coating head would be oxidized by the atmosphere and discolored, so there was a problem that the conductor heating temperature had to be kept at an insufficiently low temperature of 130℃ or less. .

For this reason, the present applicant proposed a device that prevents oxidation and heats the cable conductor by running it in an inert gas-filled chamber upstream of the extrusion coating head (Utility Model Registration Application No. 204277 of 1981 (Utility Model Registration Application No. 204277). −43766)),
This was suitable when the cable conductor was bare.

By the way, in the case of cables in which a semiconductive compound coated tape is wrapped around the cable conductor and then covered with insulation, it is difficult to install a large inert atmosphere chamber to cover the tape winding device. In addition, in the case of cables in which semiconductive tape is applied vertically to the cable conductor to insulate it, an accumulator with a large amount of tape storage is required for tape changes and tape splicing, and this is carried out in an inert atmosphere. It is not easy to wrap the accumulator in the enclosure chamber, and even if this accumulator is installed outside the inert atmosphere enclosure chamber, excessive tension and twisting will be applied to the tape as it passes through the tape entrance seal in that chamber. Uniform vertical alignment will not be possible. As described above, in the case of a cable in which a semiconductive tape is provided around the cable conductor, there is a problem in that the cable conductor cannot be heated to a sufficient temperature without oxidizing the cable conductor.

In order to solve these problems, the present invention provides a method that makes it possible to heat a cable conductor wrapped in semiconductive tape to a sufficient temperature without oxidizing it. be.

``Means for Solving the Problems'' In order to solve the above-mentioned problems, the method of the present invention provides that the tape enclosing the cable conductors is applied particularly longitudinally to the cable conductors being fed into the extrusion coating head. First, a heating device is installed upstream of the extrusion coating head to heat the running cable conductor, and this cable conductor is passed through an inert gas flow pipe connected to the outlet of the heating device, and the cable conductor is connected to the outlet of the gas flow pipe. The cable runs on an open running path between the cable conductor and the extrusion coating head, and inert gas is spouted along the running cable conductor from the outlet of the inert gas-filled tube to create a jet of inert gas around the running cable conductor. The tape, which is wrapped with a tape and attached vertically to the cable conductor, is fed along with a tape forming guide device and is attached longitudinally to the cable conductor entering the extrusion coating head, and the insulated cable coated with extrusion is run around the cable conductor in the cross-linked pipe. The cable conductor is completely surrounded by a jet of inert gas to prevent contact with air, prevent oxidation, and heat to a sufficient temperature. It is.

The details will be explained below with reference to the drawings.

FIG. 1 shows the apparatus used in the method of the invention,
FIG. 2 shows a cable in which a semiconductive tape or other tape is attached vertically to the cable conductor and an insulating coating is applied around the cable conductor. In Figure 1, W is a cable conductor that runs in the direction of the arrow, 1 is a capstan that rotates in the direction of the arrow, 2 is the head of an extrusion coating machine, and 3 is a capstan that rotates in the direction of the arrow.
is a nipple installed in the extrusion coating head 2, 4 is a crosslinked pipe connected to the outlet side of the extrusion coating head 2, and T is a semiconductive longitudinal tape, which is approximately 0.1 mm thick. Use tape made of polyester, nylon, etc. with a conductive compound pasted on it, Mylar tape, etc. This semiconductive tape T is placed along the cable conductor in the longitudinal direction, and the lengthwise side edge portions of the tape are overlapped by about 2 to 10 mm, as shown in the second figure, so as to wrap around the conductor. P is a plastic such as polyethylene which is extruded onto the cable conductor W wrapped with the longitudinal splicing tape T to form an insulating coating.

The vertically attached tape T is attached to the tape pad device 5.
The tape is fed along the cable conductor W in the vertical direction while adhering to the inner surface of the tape forming guide device 6, which continuously curves into a U-shape and a circle from the semicircular shape at the entrance toward the rear end. , is curved and wrapped around the circumferential surface of the cable conductor W. In addition, in FIG. 1, the conductor portion C coming out from the tip of the tape molding guide device 6
is shown in black to indicate that it is a cable conductor wrapped around with vertical tape T.

7 comes out from the capstan 1 and connects to the extrusion coating head 2
A heating device is installed upstream of the extrusion coating head 2 in order to heat the cable conductor W traveling in the direction, and 71 is a cylinder thereof, and 72 is a heater device around the cylinder. This heater device 72 uses a high frequency induction heating coil, an electrical heating device, or the like.

Reference numeral 8 denotes an inert gas flow pipe, the front end of which is connected to the outlet end of the heating device 7, and the running cable conductor W passed through the heating device 7 and heated is connected to the inert gas flow pipe 8. The nozzle part 8 passes through the inside and exits.
1 and run toward an extrusion coating head 2. 82 is a pressurized inert gas cylinder such as nitrogen gas, 83 is a gas pipe, and 84 is a valve, and the pressurized inert gas is passed from the cylinder 82 through the gas pipe 83 into the inert gas flow pipe 8. A pressurized inert gas atmosphere fills the periphery of the cable conductor W which is supplied to the cable conductor W and runs inside the cable conductor W.

Outlet nozzle portion 81 of the inert gas flow pipe 8
The section between the cable conductor W and the extrusion coating head 2 is opened to form an open running path A, and in this section, the cable conductor W is exposed and runs, and inert gas is ejected from the nozzle part 81 around the conductor. By forming the open running path A before the extrusion coating head 2 in this manner, it becomes possible to easily feed the longitudinally attached tape T from the tape pad device 5 to the tape forming guide device 6.

In order to preheat the cable conductor W, apply insulation coating, and continuously crosslink it using the device configured as described above,
Inert gas pressurized to at least 10 mmAq or higher is fed from the cylinder 82 into the inert gas flow pipe 8 to fill the flow pipe 8 with the pressurized inert gas, and the nozzle portion 81 at the outlet of the flow pipe 8 is filled with the pressurized inert gas. Make it squirt vigorously. Then, the cable conductor W coming out of the capstan 1 and running through the heating device 7 is heated by the heater 72, and the heated cable conductor W is immediately passed through the pressurized inert gas atmosphere in the inert gas flow pipe 8. The open running path A is run from the nozzle part 81 toward the extrusion coating head 2. At this time, pressurized inert gas is vigorously jetted from the nozzle part 81 along the circumferential surface of the cable conductor W onto the open running path A, so that the entire circumference of the cable conductor W is pressurized as shown by the broken line. Surrounded by an inert gas jet atmosphere,
Therefore, the cable conductor W runs to the extrusion coating head 2 without being exposed to air.

The cable conductor W to be fed into the nipple 3 of the extrusion coating head 2 through this open running path A is vertically supported by a tape T which comes out from the tape pad device 5 and is placed around the cable conductor W by the tape forming guide device 6. The uncrosslinked plastic P is extrusion coated.

Then, this uncrosslinked insulated cable is connected to the crosslinked pipe 4.
The crosslinking is carried out by heating the material by running the material inside the material.

Note that the length of the open running path A is the length of the nozzle 81.
If the diameter of the cable conductor W is about (conductor diameter + 2 mm) and the pressure of the inert gas is about 100 mmAq, it is about 1 m, and the temperature at which the cable conductor W is heated by the heating device 7 should be 150 to 200 °C. becomes possible.

"Effects of the Invention" As described above, the present invention heats the running cable conductor W at the front stage of the extrusion coating head 2, immediately passes it into the inert gas flow pipe 8, and connects the outlet of the flow pipe with the extrusion The cable conductor W is run on the section between it and the covered head 2 as an open running path A, and an inert gas is spouted along the running cable conductor from the outlet of the inert gas flow pipe 8 to surround the cable conductor. Since the heated cable conductor is wrapped in a jet of inert gas, it is not exposed to the atmosphere and can therefore be fed into the extrusion coating head 2 without oxidation, thus preventing the cable conductor entering the extrusion coating head from being exposed to the atmosphere. It becomes possible to heat to a sufficient temperature.

In addition, since the cable conductor entering the extrusion sheathing head 2 runs on an open running path A, it is easy to introduce a vertical splicing tape around this conductor, and since the tape does not become twisted or twisted, a good insulation sheathing cable can be obtained. It is something that can be manufactured.

[Brief explanation of drawings]

FIG. 1 shows the apparatus used in the method of the invention,
Figure 2 shows a cross section of the cable. 2: Extrusion coating head, 3: Crosslinked pipe, 7: Heating device, 8: Inert gas flow pipe, W: Cable conductor,
T: Vertical tape, A: Open running path.

Claims (1)

[Claims] 1. Pass the heated cable conductor upstream of the extrusion coating head through an inert gas flow pipe and run an open running path between the gas flow pipe outlet and the extrusion coating head, An inert gas is ejected from the cable toward the open running path to surround the running cable conductor with a jet of inert gas, and a tape is applied vertically to the cable conductor entering the extrusion coating head to extrude an insulating coating around the cable conductor. 1. A method for manufacturing an insulated conductor cable with longitudinally spliced tape, characterized in that the cable is coated and continuously crosslinked by running it in a continuous crosslinked pipe.