A WATER-COOLED ELECTRIC CABLE AND RELATIVE MANUFACTURING METHOD

Abstract

A water-cooled electric cable comprises a plurality of copper ropes wound on an inner support tube, electric terminals at the ends constrained to the ropes, an outer tube fixed in a sealed way and a plurality of sheaths), one for each rope, which are extrusion cast in plastic or rubber material on each copper rope and subsequently pierced.

Claims

1. A water-cooled electric cable, comprising a plurality of copper ropes wound on a central support, electric terminals at the ends constrained to the ropes and an outer tube fixed in a sealed way, characterised in that it comprises a plurality of sheaths, one for each rope, which are extrusion cast in plastic or rubber material on each copper rope and subsequently pierced.

2. A process for making a water-cooled electric cable, comprising a preliminary step of forming a plurality of copper ropes constituted of copper wires, characterised in that it comprises in sequence the following steps: extrusion of plastic or rubber material on each rope in such a way as to form an outer sheath on each rope; piercing the outer sheath; assembling the ropes on a central support; fixing electric terminals to the ends of the ropes; threading the ropes and terminals into an outer tube; clipping the outer tube to seal it.

3. The process according to claim 2, wherein the sheath is pierced by cutting it with pressurised water.

4. The process according to claim 2, wherein the sheath is pierced by laser cutting.

5. The process according to claim 2, wherein the sheath is pierced by die cutting.

6. The process according to claim 2, wherein it comprises a step of cutting the ropes into pieces having a predetermined length, interposed between the steps of piercing the sheath and assembling the ropes on a central support.

7. The process according to claim 2, wherein it comprises a step of laying a polymeric film, such as a polyester film, over the copper ropes immediately before the step of extrusion to form a sheath.

8. The process according to claim 2, wherein the fixing of the electric terminals to the ends of the ropes is performed with a process of simultaneous and uniform mechanical pressing on the entire cylindrical surface of the electric terminal.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Further advantages and features of the invention will become more apparent from the detailed description below with reference to the accompanying drawings, which show a non-limiting embodiment, in which:

[0019] FIG. 1 shows the invention according to a perspective view during the making process;

[0020] FIG. 2 shows the invention according to a perspective view once made, with some parts removed to better highlight others;

[0021] FIG. 3 shows a detail for the making process.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT OF THE INVENTION

[0022] As shown in FIG. 2, the invention relates to a water-cooled electric cable, comprising a plurality of copper ropes (1) wound on a central support (2), often formed by a hollow tube, electric terminals (3) at the ends constrained to the ropes (1) and an outer tube (4) fixed in a sealed way with clips (6), in which each rope (1) is covered by a sheath (5), which is extrusion cast in plastic or rubber material on the copper rope (1) itself, and subsequently pierced.

[0023] The process for making such a water-cooled electric cable (10) comprises a preliminary step of forming a plurality of copper ropes (1) constituted of copper wires, followed by a step consisting of the extrusion of plastic or rubber material on each rope (1) in such a way as to form an outer sheath (5) on each rope (1), which completely covers the rope (1). The sheath (5) is then pierced and the ropes (1), thus covered, and which can even measure tens of meters, are subsequently cut into pieces having a predetermined length according to the size characteristics of the installation for which the cables are destined.

[0024] The piercing of the sheath (5) can also be carried out by several methods. The solution that is most preferable today involves removing portions of the sheath (5) by cutting it with pressurised water, as shown in FIG. 3: the pressures involved can reach values of around 3000 bar and, although the cost of this procedure is quite significant, the cut is very well defined and the underlying copper is not ruined; moreover, the speed of the operation allows this operation to be carried out on line.

[0025] Alternative solutions can involve the use of laser cutting and die cutting. In the first case, despite a high-quality cut, the operation has the disadvantage of being slow, which forces it to be carried out off of the production line; in the second case, on the other hand, the speed of cutting is contrasted by a difficulty in removing the waste material and the fact that the copper that makes up the rope (1) is more easily damaged.

[0026] To avoid this drawback, before laying the plastic or rubber material onto the copper ropes (1), a polymeric film, for instance made of polyester, and a few microns thick, can be applied over the ropes (1).

[0027] The ropes (1) are then assembled on the central support (2) in a spiral arrangement, as shown in FIG. 1, and the electrical terminals (3) are fixed to the ends of the ropes (1): the fixing of the electrical terminals (3) to the ends of the ropes (1) can be done by braze welding or mechanical pressing. In the latter case, it is advantageous for the mechanical pressing to be performed simultaneously and uniformly on the entire cylindrical surface (3a) of the electric terminal (3).

[0028] Finally, the set of ropes (1) and terminals (3) is threaded into an outer tube (4) and then clipped to seal.