Abstract: A method for manufacturing a cable, the cable including at least one transmissive element and at least one coating layer made of a polymeric material and arranged at a radially outer position with respect to the transmissive element. The method includes the steps of: a) feeding the polymeric material to an extrusion apparatus including an extrusion head, the extrusion head including a male die; a female die coaxially arranged with respect to the male die; a conveying channel, at least one portion of which is defined between the male die and the female die; and b) controlling a cross-sectional area of the at least one portion of the conveying channel in response to a detected quantity, the quantity being caused to vary during the manufacturing of the cable as a function of the actual extrusion speed. An extrusion apparatus for carrying out the process.

Abstract: A method for manufacturing a cable, the cable including at least one transmissive element and at least one coating layer made of a polymeric material and arranged at a radially outer position with respect to the transmissive element. The method includes the steps of: a) feeding the polymeric material to an extrusion apparatus including an extrusion head, the extrusion head including a male die; a female die coaxially arranged with respect to the male die; a conveying channel, at least one portion of which is defined between the male die and the female die; and b) controlling a cross-sectional area of the at least one portion of the conveying channel in response to a detected quantity, the quantity being caused to vary during the manufacturing of the cable as a function of the actual extrusion speed. An extrusion apparatus for carrying out the process.

Abstract: A method for manufacturing a cable, the cable including at least one transmissive element and at least one coating layer made of a polymeric material and arranged at a radially outer position with respect to the transmissive element. The method includes the steps of: a) feeding the polymeric material to an extrusion apparatus including an extrusion head, the extrusion head including a male die; a female die coaxially arranged with respect to the male die; a conveying channel, at least one portion of which is defined between the male die and the female die; and b) controlling a cross-sectional area of the at least one portion of the conveying channel in response to a detected quantity, the quantity being caused to vary during the manufacturing of the cable as a function of the actual extrusion speed. An extrusion apparatus for carrying out the process.

Abstract: An extrusion method and head for depositing by extrusion a polymeric material intended, in particular, for the production of cables includes a core and a coating layer arranged at a radially outer position with respect of the core. The method includes the steps of feeding the polymeric material in a feeding duct of the extrusion head and of conveying a part of the polymeric material towards an undercut extending in the extrusion head in proximity of an end of the feeding duct. The method provides a sealing force between a head body and a conveyor element of the extrusion head exerted by means of the pushing action exerted by the polymeric material in the undercut in a direction substantially perpendicular to the longitudinal axis of the head body.

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

Abstract: A method and plant for the introduction of a liquid into a molten mass under pressure. Such a method and plant are particularly, but not exclusively, suitable for the formation of a coating layer on a cable element having at least one conductor, the layer having an extruded thermoplastic polymer forming a continuous phase incorporating a dielectric liquid, and are useful, for example, in the production of an electric cable for the transportation and/or distribution of electrical power. The method includes the steps of bringing the liquid to a predetermined pressure greater than the pressure of the molten mass; feeding the liquid into a plurality of storage tanks, and injecting the liquid into the molten mass at an injection pressure equal to the above-mentioned predetermined pressure by means of a plurality of injectors in respective fluid communication with the plurality of storage tanks.

Abstract: A method for producing a cable including at least one transmissive element, for example, an element transmitting electrical energy or optionally optical signals as well, and an expanded and cross-linked coating layer in a radially outer position with respect to the at least one transmissive element, the coating layer having a composition including an expandable and cross-linkable polymeric material. The method includes a) extruding the composition; b) forming a coating layer made of expandable and cross-linkable polymeric material with the composition thus extruded; c) expanding the coating layer made of expandable and cross-linkable polymeric material; and d) cross-linking the coating layer made of expandable and cross-linkable polymeric material. The expanding and cross-linking steps c) and d) are carried out by heating the coating layer made of expandable and cross-linkable polymeric material at atmospheric pressure by means of a suitable heating fluid.

Abstract: A multipolar cable for transmitting energy and/or signals, as well as an extrusion method and apparatus for the production thereof, is described. The multipolar cable has at least three transmissive elements and a sheath in which at least three longitudinal housings being intended to house respectively the at least three transmissive elements according to a predetermined configuration and being formed within respective substantially lobe-shaped longitudinal portions of the sheath. The multipolar cable allows the connection of the transmissive elements to one or more consumption points by means of at least one connector provided with at least three perforating elements.

Abstract: A method for manufacturing a cable, the cable including at least one transmissive element and at least one coating layer made of a polymeric material and arranged at a radially outer position with respect to the transmissive element. The method includes the steps of: a) feeding the polymeric material to an extrusion apparatus including an extrusion head, the extrusion head including a male die; a female die coaxially arranged with respect to the male die; a conveying channel, at least one portion of which is defined between the male die and the female die; and b) controlling a cross-sectional area of the at least one portion of the conveying channel in response to a detected quantity, the quantity being caused to vary during the manufacturing of the cable as a function of the actual extrusion speed. An extrusion apparatus for carrying out the process.

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: A process for manufacturing a multipolar cable having at least one pair of cores, each core having at least one conductive element and at least one layer of electrical insulation in a position which is radially external to the at least one conductive element. The process includes 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 the cores, and b) depositing by co-extrusion an expandable polymeric material in a position which is radially external to the cores so as to fill the interstitial zone and to form a filling layer of substantially circular transverse cross section, and at least one containment layer of polymeric material in a position radially external to the filling layer. The multipolar cable obtained from the process.

Abstract: An extrusion method and apparatus (11) for producing a cable (1, 101) including at least one core (7) comprising at least one transmissive element (2, 40), and at least one pair of coating layers (8, 9) arranged at a radially outer position with the respect of the core (7) are described. The method of the invention includes the simultaneous steps of depositing by co-extrusion at least one coating layer (8) of polymeric material and one coating layer (9) of expanded polymeric material and of maintaining a residual pressure not greater than the external pressure in a substantially annular interspace (21) defined between the coating layers. With respect to the methods of the prior art, the present invention allows to avoid the formation of bubbles at the interface between said at least one coating layer (8) of polymeric material and the coating layer (9) of expanded polymeric material, attaining an optimal adhesion between said layers (8, 9).

Abstract: A multipolar cable for transmitting energy and/or signals, as well as an extrusion method and apparatus for the production thereof, is described. The multipolar cable has at least three transmissive elements and a sheath in which at least three longitudinal housings being intended to house respectively the at least three transmissive elements according to a predetermined configuration and being formed within respective substantially lobe-shaped longitudinal portions of the sheath. The multipolar cable allows the connection of the transmissive elements to one or more consumption points by means of at least one connector provided with at least three perforating elements.

Abstract: A method and plant for the introduction of a liquid into a molten mass under pressure. Such a method and plant are particularly, but not exclusively, suitable for the formation of a coating layer on a cable element having at least one conductor, the layer having an extruded thermoplastic polymer forming a continuous phase incorporating a dielectric liquid, and are useful, for example, in the production of an electric cable for the transportation and/or distribution of electrical power. The method includes the steps of bringing the liquid to a predetermined pressure greater than the pressure of the molten mass; feeding the liquid into a plurality of storage tanks, and injecting the liquid into the molten mass at an injection pressure equal to the above-mentioned predetermined pressure by means of a plurality of injectors in respective fluid communication with the plurality of storage tanks.

Abstract: An electrical power cable with a foamed, compressible, semiconductive insulation shield which serves as both a cushioning layer and an electrical shield.

Abstract: An electrical cable includes a conductor, an outer sheath, and a self-repairing material layer between the conductor and outer sheath. The self-repairing material layer is distributed around the conductor in a discontinuous manner. An anchor portion is formed between the conductor and the outer sheath.

Abstract: A method for mechanically protecting a connection between at least two components forming part of an electrical and/or telecommunications network. At least one protective coating is provided, the coating being produced from an expanded polymeric material and providing the connection with a mechanical impact strength and ensuring a predetermined heat exchange between the connection and the external environment. This coating is axially and circumferentially continuous with respect to the connection. The present invention also relates to a coating for the mechanical protection of a connection between two components and to a joint thus protected.

Abstract: An extrusion method and apparatus (11) for producing a cable (1, 101) including at least one core (7) comprising at least one transmissive element (2, 40), and at least one pair of coating layers (8, 9) arranged at a radially outer position with the respect of the core (7) are described. The method of the invention includes the simultaneous steps of depositing by co-extrusion at least one coating layer (8) of polymeric material and one coating layer (9) of expanded polymeric material and of maintaining a residual pressure not greater than the external pressure in a substantially annular interspace (21) defined between the coating layers. With respect to the methods of the prior art, the present invention allows to avoid the formation of bubbles at the interface between said at least one coating layer (8) of polymeric material and the coating layer (9) of expanded polymeric material, attaining an optimal adhesion between said layers (8, 9).

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: 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.