Process for the production of a cable and device for performing this process

A process for the production of a cable having at least one covering layer consisting of a composition comprising at least one polymeric material and a mineral filler in a quantity greater than 30% by weight relative to the total weight of the composition, said cable being produced by using an extruder comprising a cylindrical casing at least one extrusion screw of preset pitch positioned within said casing and having an axis of rotation parallel to the axis of said cylinder, a charging hopper located at a first end of said casing, a filtration section located close to the head of said screw, and positioned perpendicular to the axis of said screw, a connecting flange positioned downstream from the filtration section, and an extrusion head comprising a conveyer element and a die communicating with the exterior, so as to define a second end of said casing, said process comprising the steps of:

• a) conveying at least one conducting element inside of said extruder;
• b) feeding the polymeric material and the mineral filler, optionally premixed with other components of said composition into said extruder via said charging hopper;
• c) filtering said composition transferred and plasticized by said extrusion screw;
• and
• d) depositing said composition onto said at least one conducting element;
• whereby the filtration operation is performed by using a filter support plate comprising an internal surface and a plurality of elements, which protrude therefrom and define a plurality of sectors between and within which the filtered composition flows, wherein the filtration efficiency (E) is greater than 0.8.