Cable having expanded, strippable jacket
AssigneePrysmian Cavi E Sistemi Energia S.R.L.
InventorsPaul Cinquemani, Andrew Maunder, Paolo Veggetti, Alberto Bareggi, Sergio Belli
Life of this patent
Estimating the term…
Abstract
An electric power cable contains a core and a jacket forming the exterior of the cable. The jacket is formed by extruding a first layer and a second layer over a plurality of concentric neutral elements, substantially encapsulating these elements. At least the first layer is an expanded polymeric material, by having its density reduced through the use of a foaming agent during extrusion. The second layer, which may also be expanded, is extruded around the first layer. The expanded polymeric material makes stripping the jacket easier, minimizes indentations in the cable's insulation layers, lightens the cable, and increases the cable's flexibility.
Claims23
An electrical cable for underground installation comprising:
- a core forming the interior of the cable with an outer periphery defined by an insulation shield;
- a plurality of neutral elements arranged circumferentially around a radius and helically along a length of the cable, the neutral elements electrically contacting the insulation shield of the core;
- and
- a composite outer jacket surrounding the core and forming the exterior of the cable, the composite outer jacket including an inner circumferential layer proximate to the core and an outer circumferential layer, the inner circumferential layer substantially encapsulating the plurality of neutral elements, at least the inner circumferential layer being an expanded polymeric material, the inner circumferential layer providing cushioning against impact damage to the cable during installation, providing cushioning against formation of indentations in the insulation shield from the neutral elements, and permitting stripping of the jacket using one or more of the neutral elements,
- wherein the outer circumferential layer has a degree of expansion of about 2-50%.
A method of making a cable comprising:
- providing a conductor;
- applying a shield around the conductor;
- extruding insulation over the shield;
- applying an insulation shield over the insulation;
- applying concentric neutral elements around and in contact with the insulation shield;
- expanding a polymeric material with a foaming agent;
- and
- extruding an inner circumferential layer of the expanded polymeric material and extruding an outer circumferential layer to form an outer jacket and to substantially encapsulate the concentric neutral elements while maintaining contact between the concentric neutral elements and the insulation shield, the inner circumferential layer providing cushioning against impact damage to the cable during installation, providing cushioning against formation of indentations in the insulation shield from the neutral elements, and permitting stripping of the jacket using one or more of the neutral elements,
- wherein the outer circumferential layer of polymeric material has a degree of expansion of about 2-50%.
An electrical cable for underground installation comprising:
- a core forming the interior of the cable with an outer periphery defined by an insulation shield;
- a plurality of neutral elements arranged circumferentially around a radius and helically along a length of the cable, the neutral elements electrically contacting the insulation shield of the core;
- and
- a composite outer jacket surrounding the core and forming the exterior of the cable, the composite outer jacket including an inner circumferential layer proximate to the core and an outer circumferential layer, the inner circumferential layer substantially encapsulating the plurality of neutral elements, the inner circumferential layer and the outer circumferential layer each being an expanded polymeric material and having a degree of expansion in the range of about 2% to 50%.
A method of making a cable comprising:
- providing a conductor;
- applying a shield around the conductor;
- extruding insulation over the shield;
- applying an insulation shield over the insulation;
- applying concentric neutral elements around and in contact with the insulation shield;
- expanding a polymeric material with a foaming agent;
- and
- extruding an inner circumferential layer of the expanded polymeric material and extruding an outer circumferential layer to form an outer jacket and to substantially encapsulate the concentric neutral elements while maintaining contact between the concentric neutral elements and the insulation shield, the inner circumferential layer and the outer circumferential layer each having a degree of expansion in the range of about 2% to 50%.
Dependencies are inferred from the claim text.