JPH0680221U - Cable bridge equipment - Google Patents

Abstract

(57) [Summary] [Purpose] Omit or significantly shorten the drying process for crosslinked cables. [Structure] The cable bridging device 1 includes an extruder 2 and a heating unit A.
And a bridging pipe 3 including a cooling section B and a drying chamber 4,
The conductor 5 wound around the delivery drum 15 is guided to the extruder 2 via a guide roller 16, and the outer periphery of the conductor 5 is covered with uncrosslinked polyethylene containing a crosslinking agent. The cable 6 is heated to about 200 ° C. in the heating section A in the cross-linking tube 3 to cross-link the insulator, and then heated to about 90 ° C. in the cooling section B.
The cooled cable 6 is guided to the drying chamber 4 connected to the bridge pipe 3, and the drying chamber 4 is passed through the guide roller 13 and the support roller 14 while maintaining the temperature after passing through the cooling unit. Water, cumyl alcohol, and methane gas, which are residues of cross-linking decomposition in the insulator, are removed as much as possible, and are taken up by the take-up drum 17.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a cable bridging device, and more particularly to an improvement of a cable bridging device suitable for manufacturing a high-pressure crosslinked polyethylene cable.

[0002]

[Prior art]

 Conventionally, as an apparatus for manufacturing rubber and plastic cables, especially cross-linked polyethylene cables, an extrusion apparatus for extrusion-coating an uncross-linked insulating material, and a device connected to this extrusion apparatus and kept in an inert gas atmosphere There is known a cable bridging device provided with a bridging pipe including a heating part and a cooling part accommodating cooling water.

In this apparatus, a cross-linked polyethylene cable is manufactured by extrusion-coating an uncross-linked polyethylene compounded with a cross-linking agent on the outer circumference of a conductor, cross-linking this in a heating section, and then cooling it in a cooling section. It In the above device, although it is possible to avoid deterioration of electrical characteristics due to water vapor permeation into the insulator compared to water vapor crosslinking using water vapor as a heating medium, moisture contained in an inert gas such as nitrogen gas And decomposition products of the crosslinker may cause the generation of aqueous trees.

That is, the nitrogen gas in the heating part is blown or circulated in order to prevent an increase in the water content in the gas, but dicumyl peroxide generally used as a cross-linking agent is polyethylene. During the crosslinking reaction, it decomposes itself to form decomposition residues such as water, cumyl alcohol and methane. Of course, water is one of the residues of decomposition of the cross-linking agent, but cumyl alcohol also re-decomposes during use to generate water, which causes generation of aqueous trees. In addition, methane gas increases the internal pressure of the sheath and causes blistering of the sheath and detachment of the cap at the terminal.

Further, among the above-mentioned cross-linking decomposition residues, it is considered that water migrates to nitrogen gas to some extent, but when the water content in nitrogen gas increases, the water remaining amount in the insulator increases. There is also the possibility of moisture ingress into the insulation. Therefore, when manufacturing a crosslinked polyethylene cable, especially a high-pressure crosslinked polyethylene cable, it is necessary to remove moisture, cumyl alcohol, and methane gas, which are residues of crosslinking decomposition in the insulator, as much as possible.

[0006]

[Problems to be solved by the device]

 From the above points, in order to remove the cross-linking decomposition residue in the insulator, the insulating core is wound on a drum and then degassed in a drying chamber. This degassing is performed, for example, by heating to 60 to 90 ° C. in the atmosphere, nitrogen gas or vacuum.

However, since this drying step is performed while the insulating core is wound on the drum or wound in the basket, there is a problem that deformation due to the weight of the cable is likely to occur. In order to prevent the deformation due to the weight of the cable, it is necessary to carefully consider the uneven load and the cushion material especially on the high temperature side in the drying chamber.

Further, the time required for drying depends on the purpose, but for example, in the case of a 154 kV class cable, it takes about 10 days to remove methane gas, and 20 to 30 days to remove water. There is a problem that the number of days is required and the process requires a lot of time. The present invention has been made in order to solve the above-mentioned problems, and the drying process is arranged in tandem in the bridge pipe to simplify the manufacturing process of the bridge cable.

[0009]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, a cable bridging device of the present invention is an extrusion device for extruding and covering an unbridged insulator on the outer circumference of a conductor, and is connected to this extrusion device and kept in an inert gas atmosphere. A bridge tube consisting of a heating section and a cooling section and a drying chamber connected to this bridge tube are arranged in sequence.

Since the drying chamber in the present invention is arranged for the purpose of removing moisture, cumyl alcohol, and methane gas, which are residues of cross-linking decomposition in the insulator, as much as possible here, the atmosphere thereof is inert to nitrogen gas and the like. It is preferable to constantly supply a gas atmosphere, particularly an inert gas having a low water content, or to maintain the atmosphere in a vacuum atmosphere. Further, by keeping the temperature of the drying chamber at a temperature equal to or higher than the temperature of the insulator after passing through the cooling section of the bridge, it is possible to efficiently remove the crosslinking decomposition residue in the insulator. For this reason, a heating means is arranged in the drying chamber as needed.

It is natural that the longer the drying chamber is, the more the drying effect is improved, but the length is determined in consideration of the facility cost.

[0012]

[Action]

 With the above-described configuration, in the cable bridging device of the present invention, by connecting the bridging tube to the drying chamber in tandem, it is possible to continuously dry the cable having residual heat after passing through the cooling unit, and the drying process is performed. Since it can be omitted or significantly shortened, the manufacturing process of the crosslinked cable can be simplified.

[0013]

【Example】

 An embodiment of the present invention will be described below. FIG. 1 is a schematic view of a cable bridging device 1 of the present invention, in which 2 is an extruder, 3 is a bridging tube comprising a heating section A and a cooling section B, and 4 is a drying chamber. The upper part of the cross-linking pipe 3 is connected to the extruder 2 via a splice box (not shown), while the lower part thereof is connected to the drying chamber 4 arranged in a substantially horizontal direction.

The heating section A of the cross-linking tube 3 heats the insulator of the cable 6 extruded to the outer periphery of the conductor 5 by the extruder 2 by means such as a heater 7 or a high frequency induction heating coil (not shown) to insulate the insulation. Cross-link the body. Further, the cooling water B is contained in the cooling section B of the bridging pipe 3 to cool the insulator after the bridging.

Nitrogen gas is filled in the heating portion A of the above-mentioned cross-linking pipe 3, and in order to suppress an increase in the amount of water in this gas, nitrogen gas is usually supplied and discharged in an appropriate amount at all times. . In this cross-linking pipe 3, for example, the inside of the heating part A is maintained at about 200 ° C., and the insulator of the cable 6 in the cooling part B is below the melting point of polyethylene (103 ° C.), usually about 90 ° C. from the viewpoint of safety management. It is cooled to ℃.

The lower part of the cooling section B is sealed by a packing 9, and the leaked water from this packing 9 is discharged from a drain port 10 provided below the connecting portion between the bridge pipe 3 and the drying chamber 4. . In the drying chamber 4, in order to prevent the oxidative deterioration of the insulator at high temperature and suppress the increase of the moisture concentration in the atmosphere, for example, nitrogen gas is supplied from the gas supply port 11 and discharged from the gas discharge port 12 at the same time. To be done.

In the drying chamber 4, it is desirable to maintain the temperature of the insulator at about 90 ° C. so that the temperature of the insulator does not decrease after passing through the cooling section B. A guide roller 13 and a support roller 14 for guiding the cable 6 from the cooling section B 1 to the drying chamber are arranged in the drying chamber 4, but the temperature of the insulator is below the melting point in this region. No problem. In the above apparatus, the drying chamber 4 is filled with nitrogen gas, but the inside can be maintained in a high vacuum in order to further enhance the drying effect. In this case, since there is no heat conductor, it is necessary to use radiation heating and high frequency induction heating together.

In carrying out the present invention by the cable bridging device 1 configured as described above, first, the conductor 5 wound around the feed drum 15 is guided to the extruder 2 through the guide roller 16, Here, uncrosslinked polyethylene containing a crosslinking agent is coated on the outer periphery thereof. Next, the cable 6 is heated to about 200 ° C. in the heating section A in the cross-linking tube 3 to cross-link the insulator, and then cooled to about 90 ° C. in the cooling section B.

After cooling, the cable 6 is guided to the drying chamber 4 connected to the bridge pipe 3 and, while maintaining the temperature after passing through the cooling section, via the guide roller 13 and the supporting roller 14, ... Water, cumyl alcohol, and methane gas, which are residues of cross-linking decomposition in the insulator, are removed as much as possible, and are taken up by the take-up drum 17.

[0020]

[Effect of device]

 As described above, according to the cable bridging device of the present invention, compared with the conventional bridging cable manufacturing process, the drying step can be omitted or significantly shortened, and the cable deformation can be prevented. Have.

[Brief description of drawings]

FIG. 1 is a schematic view of a cable bridging device of the present invention.

[Explanation of symbols]

 1 ... Cable cross-linking device 2 ... Extruder 3 ... Cross-linking pipe 4 ... Drying chamber 5 ... Conductor 6 ... Cable 11 ... Gas supply port 12 ... Gas discharge port A ... Heating part B ... Cooling part

Claims (3)

[Scope of utility model registration request] 1. An extruding device for extruding and coating an uncrosslinked insulating material on the outer circumference of a conductor, a crosslink pipe connected to the extruding device and comprising a heating part and a cooling part held in an inert gas atmosphere, and the crosslink. A cable bridging device characterized in that a drying chamber connected to a pipe is sequentially arranged. 2. The cable bridging device according to claim 1, wherein the drying chamber is maintained in an inert gas atmosphere or a vacuum atmosphere. 3. The cable bridging device according to claim 1, wherein the drying chamber is maintained at a temperature equal to or higher than the temperature of the insulating material after passing through the cooling section of the bridging tube.