Cooling case for an electrical device, and a method of manufacturing it

A cooling case for an electrical device, the case comprising:

• a thermally conductive inner ferrule for surrounding the electrical device, the inner ferrule being a body of revolution;
• and
• an outer enclosure adjacent to the outside surface of the inner ferrule and including a feed inlet and an exhaust outlet for a cooling fluid, the outer enclosure being in the form of a plurality of undulations,
• the undulations comprising:
• first portions in contact with the outer surface of the inner ferrule, and
• second outer portions offset from the outer surface of the inner ferrule and, cooperating with the inner ferrule, defining a passage for the cooling fluid,
• the first and second portions being rigidly connected to each other;
• the passage for the cooling fluid extending from the inlet to the outlet and being helical in shape;
• the inner ferrule being suitable for coming into thermal contact with the cooling fluid;
• and
• wherein the undulations are such that the passage includes two substantially parallel sections that communicate with each other at one end via a bend such that the fluid inlet and the fluid outlet are located substantially towards the same free opposite ends of said sections.

A method of manufacturing a cooling case for an electrical device, comprising the steps of:

• providing a thermally conductive inner ferrule for surrounding the electrical device, the inner ferrule being a body of revolution;
• and
• providing an outer enclosure for attachment to the outside surface of the inner ferrule, said outer enclosure including a feed inlet and an exhaust outlet for a cooling fluid, and the outer enclosure being in the form of a plurality of undulations,
• the undulations comprising:
• first portions in contact with the outer surface of the inner ferrule, and
• second outer portions offset from the outer surface of the ferrule and designed to define a passage for the cooling fluid when attached cooperatingly with the inner ferrule;
• the first and second portions being rigidly connected to each other;
• the passage for the cooling fluid extending from the inlet to the outlet and being helical in shape;
• the inner ferrule being suitable for coming into thermal contact with the cooling fluid;
• wherein the undulations are such that the passage includes two substantially parallel sections that communicate with each other at one end via a bend such that the fluid inlet and the fluid outlet are located substantially towards the same free opposite ends of said sections, and wherein the undulations are created by plastic deformation of the outer enclosure;
• fitting the inner ferrule inside the outer enclosure deformed in this way;
• and
• welding the outer enclosure to the inner ferrule in leakproof manner via their ends.