UNITIZED ELECTRIDE HOLDER AND ARM FOR ELECTRIC ARC FURNACE ELECTRODES OR THE LIKE

摘要

The disclosed structure comprises a combined electrode holder and supporting arm for holding an electric furnace electrode or the like. The holder includes a clamping device mounted on the outer end of a tubular supporting arm which is preferably made of nonmagnetic stainless steel or some other high strength nonmagnetic material. The clamping device includes a contact member or shoe and means for producing clamping pressure between the contact member and the electrode. The electrical current is supplied to the contact member by a bus tube extending longitudinally within the tubular supporting arm, preferably along the axis thereof. The contact member and the bus tube are made of copper or some other material having high electrical conductivity. Within the tubular supporting arm the bus tube is surrounded by a shielding tube made of copper or some other material having high electrical conductivity. Generally, the shielding tube is electrically insulated from the bus tube and the supporting arm, although an electrical connection between one end of the shielding tube and the corresponding end of the supporting arm is permissible. The shielding tube acts as a magnetic shield around the bus tube and thus prevents the supporting arm from being heated by eddy currents induced in the supporting arm by the magnetic field around the bus tube. The shielding tube confines the magnetic field of the bus tube to the space between the bus tube and the shielding tube.