Constructive arrangement in an umbilical cable and a process for the manufacture thereof

A method for manufacturing an umbilical cable having an outer wall comprising an external sheath of insulating polymeric material, a metal shielding and an inner sheath of insulating polymeric material enclosing at least two three-phase power supply circuits, each made of three conductors bundled together in a trefoil configuration, each conductor comprising a metal core surrounded by an insulating sheath, each said conductor comprising an individual shield surrounding said insulating sheath, the method comprising:

• a. forming a central metallic core of each conductor;
• b. extruding the insulating sheath over said central core;
• c. applying the shielding over said insulating sheath;
• d. storing each conductor on an individual bobbin;
• e. installing, in a cabling machine, as many bobbins as power conductors of any electrical voltage, that will form the umbilical cable;
• f. in one single pass through the cabling machine, joining said conductors in groups of three, twisting them in a helical configuration to bundle them into trefoils, all trefoils having a same pitch, and grouping said trefoils together in positions within the cable;
• g. extruding the inner sheath of insulating polymeric material over an assembly of trefoils;
• h. applying a metal shield over said inner sheath;
• and
• i. extruding an external sheath of insulating polymeric material over said metal shield.