Metallic sheath for an electric cable and method of making the same
AssigneeAlcatel Kabel AG & Co.
InventorGerhard Ziemek
Life of this patent
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Abstract
A metallic sheath for an electric cable with a ratio of inner diameter Di to outer diameter Do of at least 0.9, comprises a lengthwise welded, annularly or helically shaped corrugated tube whose wall thickness is in a range between 0.005 and 0.009 of the outer diameter, and where the distance p between two neighboring corrugation crests is in a range between 0.08 and 0.12 of the outer diameter. In addition, a method of making the above described electric cable is described.
Claims14
A metallic sheath for an electric cable, which comprises a corrugated metal tube having:
- (a) a ratio of inner diameter to outer diameter of more than 0.90;
- (b) a wall thickness in a range of from 0.005 to 0.09 of the outer diameter;
- and
- (c) a corrugation pitch in a range of from 0.08 to 0.12 of the outer diameter.
In an electric power cable with a conductor, conductor shield, a layer of plastic insulation, a conductive outer layer placed over the plastic layer, and a metallic cable sheath which is applied to the conductive outer layer, the improvement comprising the cable sheath is a corrugated tube having:
- (a) a ratio of inner diameter to outer diameter of more than 0.90;
- (b) a wall thickness in a range of from 0.005 to 0.09 of the outer diameter;
- and
- (c) a corrugation pitch in a range of from 0.08 to 0.12 of the outer diameter.
A method for producing an electric power cable, which comprises the steps of:
- (a) drawing a metal tape from a storage spool;
- (b) forming the metal tape into a tube with a lengthwise slot;
- (c) drawing a cable core from a storage drum;
- (d) inserting the cable core into the lengthwise slotted tube, where the inner diameter of the lengthwise slotted tube is larger than the outer diameter of the cable core;
- (e) welding the lengthwise slotted tube to close the slot and form a welded tube;
- and
- (f) corrugating the welded tube to form a corrugated tube with troughs of the corrugated tube gripping the cable core, the corrugated tube having the following parameters:
- (i) inner diameter/outer diameter .gtoreq.0.90;
- (ii) wall thickness is in a range of from 0.005 and 0.009 of the outer diameter;
- and
- (iii) corrugation pitch in a range of from 0.08 to 0.12 of the outer diameter.
Dependencies are inferred from the claim text.