Coaxial cable prodn., esp. for cable television - in which outer conductor is formed by bending copper strip into tube and plasma welding

摘要

Coaxial cable is made by covering an inner conductor with insulation followed by metal strip, esp. copper strip which is bent round the insulation to form a tube; and the longitudinal, butting edges of the bent strip are joined by plasma welding. The cable is pref. fed past the plasma welding burner at 4-20, esp. 5-12 metres/min., using a welding current of 30-300 A, esp. 100-150 A, the higher currents being used with the higher welding speeds. A transferred plasma arc is pref. used with arc length 1-2 mm, the plasma gas being Ar and the inert gas shield Ar and/or He. Method is used e.g. for mfg. coaxial cable for television esp. for cable television where higher electrical sealing can be achieved than with conventional cable mfr.