Manufacture procedure for cable with reduced friction for sheath

摘要

The procedure involves spraying small balls (4) onto the sheath (2) after it is applied by extrusion onto the cable core (1). They are sprayed in a coating chamber (6) while the sheath is still hot. Then the cable with the coating of balls is cooled in another chamber (7). When the cable is later pulled into a pipe or channel, the balls become detached automatically. The small balls are of hard inorganic material. They have a diameter of between 50 and 300 micrometres. Suitable materials for the balls are glass, talcum, ceramic and powdered quartz.