JPS5919609B2 - How to make copper oxide film on copper stranded wire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Background and Purpose As an example of strand insulation for power cable conductors, it has been proposed to form a thin copper oxide film on the surface of copper strands.

This copper oxide film can be made, for example, by immersing a copper conductor in an oxidizing solution. When using this chemical oxidation method to create a copper oxide film on the surface of stranded copper wire,
The issue is whether the oxidation treatment can be done uniformly to the internal wires.

In particular, compression-molded segment i used for stranded conductors of high-voltage, large-capacity cables has few gaps between wires, so uniform oxidation treatment is difficult. This invention enables uniform oxidation treatment even in the above-mentioned cases.

Structure of the Invention As shown in FIGS. 1 to 3, the copper stranded wire 10 enters the oxidation treatment liquid 14, runs therein, and exits the oxidation treatment liquid 14 continuously, and It is characterized in that the pressure in the gap between the strands inside the stranded wire 10 immediately before and after entering the oxidation treatment liquid 14 is lower than the pressure of the oxidation treatment liquid 14.

There are two methods for making the pressure in the gap between the strands inside the twisted wire 10 lower than that of the oxidation treatment liquid 14 as described above.

C. The pressure between the wires in the stranded wire 10 is maintained at atmospheric pressure, and the oxidation treatment liquid 14 is pressurized.

2) The air inside the stranded wire 10 is sucked out using a vacuum pump 32 or the like to create a negative pressure.

In this way, since the gaps between the strands are continuous in the length direction within the stranded wire 10, when the pressure inside the stranded wire 10 is lowered outside the oxidation treatment liquid 14, the oxidation treatment liquid 14
Even inside the wire, a pressure difference is created between the pressure in the gap between the wires and the oxidation treatment liquid 14.

When a pressure difference occurs between the outside and inside of the stranded wire in this manner, the oxidizing solution permeates into the small gaps within the stranded wire, causing a flow of the oxidizing solution. Eleventh Example (FIG. 1) 10 is a copper strand, for example a compression molded segment.

12 is a container, 14 is an oxidation treatment liquid, for example, a mixed aqueous solution of sodium chlorite and caustic soda; 15 is a liquid seal;
16 is an air vent valve.

The oxidation treatment liquid 14 is heated to about 100° C. by a suitable heating means (not shown). 18 is a receiving container with a seal 15
The oxidation treatment liquid 14 leaking from the tank is accommodated.

20 is a seal.

22 is a tank, which is also provided with heating means (not shown).

Reference numeral 24 denotes a pressurizing pump, which pressurizes and circulates the oxidation treatment liquid 14 in the container 12.

The pressurized oxidation treatment liquid 14 forcibly discharges the air within the stranded wire 10 and replaces it, easily entering even the small gaps between the wires and forming a copper oxide film. The evacuated air (air bubbles 26) collects on top of the container 12 and is discharged through the air bleed valve 16. Note that by pressurizing the oxidation treatment liquid 14, its boiling point increases.

This increases the oxidation reaction rate and can be expected to increase the linear velocity. Second Embodiment (FIG. 2) A columnar portion 121 is provided in the container 12, and the oxidation treatment liquid 14 is pressurized by a liquid column 141 therein.

Pump 24 is used solely for circulation. The rest is the same as in the first embodiment. In this case, the bubbles 26 can be particularly easily discharged.

Air vent valve 16 is not required. Third Embodiment (FIG. 3) Reference numeral 28 is a vacuum container, which is provided on both sides of the container 12.

30 is an air seal.

32 is a vacuum pump, and 34 is a drain tank.

The vacuum pump 32 sucks the air inside the stranded wire 10 to create a negative pressure inside the stranded wire 10 . Then, the oxidation treatment liquid 14 penetrates into every corner of the stranded wire 10. Drain tank 34
The accumulated oxidation treatment liquid 14 is returned to the tank 22. Air is exhausted 36. Due to the effect of the invention, the pressure in the gap between the wires in the wire 10 is reduced by the oxidation treatment liquid 14.
Even in the case of a stranded wire conductor with a small internal gap, such as a compression molded segment, it is possible to uniformly insulate the strands to the inside.

[Brief explanation of drawings]

FIG. 1, FIG. 2, and FIG. 3 are explanatory diagrams of different examples of devices used to implement the present invention. 10...Twisted wire, 12...Container, 14
... Oxidation treatment liquid, 24 ... Pump, 3
2...Vacuum pump.

Claims (1)

[Claims] 1. A stranded copper wire enters the oxidizing solution, runs inside it, then comes out of the oxidizing solution and runs continuously, and the stranded wire immediately before and after entering the oxidizing solution. A method for forming a copper oxide film on a stranded copper wire, characterized in that the pressure in the gap between the strands inside the wire is lower than the pressure of the oxidation treatment liquid.