Method of making a heating device for utilizing the skin effect of alternating current

Claim 1

In a heating system utilizing the skin effect of alternating current in which a power cable comprising a primary conductor surrounded by a layer of semiconductor material, a primary insulation layer, a shield layer and an outer insulation jacket, is disposed with a heat tube and which operates with a continuous applied voltage of at least 5 KV and at a temperature of substantially 210° C., a method for joining a feed end of a length of the power cable to a terminal end of another length of the power cable, comprising the steps of: a. removing the outer insulation jacket at the feed and terminal ends of said lengths of power cable to expose a predetermined length of said shield layer extending from the extreme ends of the cable to a first position spaced from said ends; b. removing the shield layer, primary insulation layer and semiconductor layer from each cable end to expose the primary conductor for a distance extending from the extreme ends of the cables to a second position intermediate the ends of the cables and said first positions; c. removing the shield layer from each cable end between said second position and a spaced, third position located intermediate said first and second position, leaving a portion of the shield layer exposed extending between said first and third positions; d. mechanically joining together the exposed primary conductors of each cable end to form a conductor joint; e. wrapping semiconductor material around the exposed conductor ends to completely cover said conductor joint, said material extending between the second positions of each cable end; f. wrapping insulation material across said joint between the third position of the cable lengths until a partial insulation layer of predetermined thickness is formed, said partial layer being less than the final desired insulation thickness; g. heat fusing said layer of wrapped insulation; h. repeating steps (f) and (g) to obtain a substantially void free, final insulation thickness at least as thick as said primary insulation layer of said cables; i. wrapping a semiconductor material from the first position of one cable end to a fourth position located intermediate the conductor joint and the third position of the other cable end; j. wrapping insulation material over said semiconductor material and heat fusing said material to form a substantially void free insulation layer extending substantially between the first position of said one cable end to the third position of said other cable end; k. electrically communicating the shield layer of said other cable end with said heat tube; l. wrapping semiconductor material from the first position of the other cable end to a position located intermediate the conductor joint and the first position of the one cable end; and, m. wrapping insulating material across said joint and heat fusing said material to form another layer of substantially void free insulation at least as thick as the outer insulation jacket of said cables, extending between the first positions of the joined cable ends.