Abstract: The present invention concerns a process for producting cables, in particular cables for the distribution of electrical energy or cables for telecommunications, more particularly, cables having at least one covering layer comprising a composition of high viscosity. More particularly, the present invention concerns cables having at least one covering layer comprising a polymeric composition comprising a mineral filler capable of imparting one or more specific properties to the aforesaid cables. In accordance with the present invention, said production process comprises the stages of: conveying at least one conducting element inside of an extruder; feeding the polymeric material, optionally premixed with other components of said composition, into said extruder, filtering the material transferred and plasticized by the screw of said extruder; depositing said material onto said at least one conducting element, the filtration operation being performed with a filtration efficiency greater than 0.

Abstract: A cable comprises at least two cores stranded together, an expanded inner jacket layer, a substantially circular metallic armor partially contacting the inner jacket to form unfilled interstices outside the inner jacket, and a polymeric outer jacket. The expanded inner jacket substantially takes the shape of the periphery of the stranded cores, providing a non-circular cross section for the expanded inner jacket. A method of producing a cable comprises providing at least two cores, expanding a polymeric material, extruding the expanded polymeric material around the cores, and allowing the expanded polymeric material to collapse onto the cores. A substantially circular metallic armor is applied, resulting in a plurality of unfilled voids between the inner jacket and the metallic armor. An outer jacket is extruded on the metallic armor.

Abstract: Electric cable (20), in particular for power transmission or distribution at medium or high voltage, comprising a metallic screen (5) and a water swellable layer (21) capable of forming a barrier to the water penetration provided in a position radially external to said metallic screen (5). Said water swellable layer (21) is made of an expanded polymeric material in which a water swellable material preferably in the form of powder, is embedded.

Abstract: A cable comprises at least two cores stranded together, an expanded inner jacket layer, a substantially circular metallic armor partially contacting the inner jacket to form unfilled interstices outside the inner jacket, and a polymeric outer jacket. The expanded inner jacket substantially takes the shape of the periphery of the stranded cores, providing a non-circular cross section for the expanded inner jacket. A method of producing a cable comprises providing at least two cores, expanding a polymeric material, extruding the expanded polymeric material around the cores, and allowing the expanded polymeric material to collapse onto the cores. A substantially circular metallic armor is applied, resulting in a plurality of unfilled voids between the inner jacket and the metallic armor. An outer jacket is extruded on the metallic armor.

Abstract: An extrusion method and apparatus for producing a cable including at least one core having at least one transmissive element and at least one pair of coating layers arranged at a radially outer position with respect to the core. At least one coating layer of polymeric material and one coating layer of expanded polymeric material are deposited by co-extrusion simultaneously and residual pressure not greater than the external pressure is maintained in a substantially annular interspace defined between the coating layers. The method avoids the formation of bubbles at the interface between the at least one coating layer of polymeric material and the coating layer of expanded polymeric material, attaining an optimal adhesion between the layers.

Abstract: Self-extinguishing cable, in particular an electrical cable for low-voltage or medium-voltage power transmission or distribution of data transmission, having at least one conductor and at least one flame-retardant coating positioned externally to the conductor. The flame-retardant coating is produced from an expanded polymeric material which incorporates at least one intumescent agent.

Abstract: An extrusion method and apparatus for producing a cable including at least one core having at least one transmissive element and at least one pair of coating layers arranged at a radially outer position with respect to the core. At least one coating layer of polymeric material and one coating layer of expanded polymeric material are deposited by co-extrusion simultaneously and residual pressure not greater than the external pressure is maintained in a substantially annular interspace defined between the coating layers. The method avoids the formation of bubbles at the interface between the at least one coating layer of polymeric material and the coating layer of expanded polymeric material, attaining an optimal adhesion between the layers.

Abstract: A method and apparatus for preheating the conductor elements of cables with extruded insulator essentially by forced thermal convection. Particularly for conductors with metal tape reinforcement, such as for example Milliken conductors, where it has been found that the traditional magnetic-induction heating is not satisfactory since the tape reinforcement shields the elements of conductors.

Abstract: The present invention concerns a process for producting cables, in particular cables for the distribution of electrical energy or cables for telecommunications, more particularly, cables having at least one covering layer comprising a composition of high viscosity. More particularly, the present invention concerns cables having at least one covering layer comprising a polymeric composition comprising a mineral filler capable of imparting one or more specific properties to the aforesaid cables. In accordance with the present invention, said production process comprises the stages of: conveying at least one conducting element inside of an extruder; feeding the polymeric material, optionally premixed with other components of said composition, into said extruder, filtering the material transferred and plasticized by the screw of said extruder; depositing said material onto said at least one conducting element, the filtration operation being performed with a filtration efficiency greater than 0.

Abstract: A process for producing cables, in particular cables for the distribution of electrical energy or cables for telecommunications, more particularly, cables having at least one covering layer having a composition of high viscosity. cables with at least one covering layer are made from a polymeric composition having a mineral filler capable of imparting one or more specific properties to the cables. A production process includes conveying at least one conducting element inside of an extruder; feeding the polymeric material, optionally premixed with other components of the composition, into the extruder; filtering the material transferred and plasticized by the screw of said extruder; and depositing the material onto the at least one conducting element, the filtration operation being performed with a filtration efficiency greater than 0.8, preferably greater than 0.9.

Abstract: The present invention relates to a manufacturing process of a multipolar cable comprising at least one pair of cores, each core comprising at least one conductive element and at least one layer of electrical insulation in a position which is radially external to said at least one conductive element. This process comprises the steps of: a) assembling said at least one pair of cores so as to form an assembled element having a plurality of interstitial zones between said cores, and b) depositing by co-extrusion an expandable polymeric material in a position which is radially external to said cores so as to fill said interstitial zone and to form a filling layer of substantially zone and to form a filling layer of substantially circular transverse cross section, and at least one containment layer of polymeric, and at least one containment layer of polymeric material in a position radially external to said filling layer. The present invention also relates to a multipolar cable obtained from said process.

Abstract: Electric cable (20), in particular for power transmission or distribution at medium or high voltage, comprising a metallic screen (5) and a water swellable layer (21) capable of forming a barrier to the water penetration provided in a position radially external to said metallic screen (5). Said water swellable layer (21) is made of an expanded polymeric material in which a water swellable material preferably in the form of powder, is embedded.

Abstract: The method and the apparatus of the invention use preheating essentially by forced thermal convection. Particularly for conductors with metal tape reinforcement, such as for example Milliken conductors, where it has been found that the traditional magnetic-induction heating is not satisfactory since the tape reinforcement shields the conductors elements.

Abstract: Self-extinguishing cable, in particular an electrical cable for low-voltage or medium-voltage power transmission or distribution of data transmission, having at least one conductor and at least one flame-retardant coating positioned externally to the conductor. The flame-retardant coating is produced from an expanded polymeric material which incorporates at least one intumescent agent.

Abstract: The present invention concerns a process for producting cables, in particular cables for the distribution of electrical energy or cables for telecommunications, more particularly, cables having at least one covering layer comprising a composition of high viscosity. More particularly, the present invention concerns cables having at least one covering layer comprising a polymeric composition comprising a mineral filler capable of imparting one or more specific properties to the aforesaid cables. In accordance with the present invention, said production process comprises the stages of: conveying at least one conducting element inside of an extruder; feeding the polymeric material, optionally premixed with other components of said composition, into said extruder; filtering the material transferred and plasticized by the screw of said extruder; depositing said material onto said at least one conducting element, the filtration operation being performed with a filtration efficiency greater than 0.