Abstract: A nozzle assembly constituting a burner or blowing nozzle includes, in the region of the discharge opening thereof, a piston-like member which is displaceable by an actuating means into a position of blocking off the discharge opening thereby to prevent same from becoming clogged by slag or metal splashed thereon. When the assembly is mounted in the wall of a metallurgical furnace, the piston-like member may also be adapted to close off the opening in the wall, which communicates with the nozzle assembly, in order also to keep the wall opening open. At least a part of the piston-like member may be caused to oscillate or at least the part thereof which is towards the interior of the furnace may comprise or be coated with a scale-resistant material or may be coated with a material that is difficult to wet.

Abstract: Apparatus for disconnecting a residual portion of a consumed graphite electrode from a permanent electrode which has been lifted out of an electric furnace and which may still be hot, and for connecting a fresh graphite electrode portion to the permanent electrode, comprises a housing for surrounding the electrode assembly in the region of a screw nipple on the permanent electrode. Disposed in the upper region of the housing is an upper clamping means for holding the permanent electrode, while disposed in the lower region of the housing is a lower clamping means which can produce a screwing movement for unscrewing and screwing on the graphite electrode portion. The housing is of a double-walled construction to provide for water cooling thereof.

Abstract: A fluid-cooled holder for the tip of an electrode of an electric arc smelting furnace, having a cylindrical holding portion which can be secured to an electrode support arm, a metal cooling system which is secured to the holding portion and which carries a screw-threaded portion for screwing on the electrode tip, and also having a tubular heat screen which is disposed around the cooling system at a spacing and which comprises a metal tube (11, 11a) which is electrically insulated with respect to the current-carrying cooling system (3, 3a) and which can be sufficiently cooled, by way of a refractory substance (17, 17a) between the cooling system and the metal tube, for the temperature of the metal tube to be kept to a value below the softening temperature of the material of the metal tube, when the holder is used in an electric arc smelting furnace.