Abstract: A plasma burner comprises an electrode holder which carries a tubular outer electrode and a coaxially arranged central electrode, and an electrical current supply source, which can be coupled via current feeders to the outer and central electrodes respectively. Also a device is provided for feeding gas into the region of the electrodes, between which an arc is produced for plasma formation. The tubular outer electrode has a first cooled, arc-inactive tube section, consisting of electrically conductive metal, and an adjoining second arc-active uncooled tube section, which consists of heat-resistant and electrically conductive material, and which is releasably connected to the first tube section. The arc passes between the second tube section and the neighboring arc-active section of the coaxial central electrode.

Abstract: Temperature-resistant materials as protective coat for the metal shaft of combination electrodes for the electric steel production, constituting a compound material comprising a carbon share, which contains graphitic structural elements, and a share with at least one ceramic component. The protective elements, which are made of these materials, are characterized by long service times, little susceptibility to unwanted adhesive matter, and good emergency running properties.

Abstract: In an electrode for electric arc furnaces, having a water-cooled metallic electrode holder and a consumable section connected to the electrode holder by means of a threaded nipple, the electrode holder having a protective jacket made up of rings. A disc positioned between the consumble section and the electrode holder which, in the event of a fracture of the consumable section, remains attached to the electrode holder for protection against electric arc strike.

Abstract: An electrode for arc furnaces, comprising a metallic water-cooled upper section and a consumable, replaceable lower section, interconnected by means of a threaded nipple or the like. At least one light-receiving element is positioned in a zone associated with the interconnection of the cooled metal shaft and the consumable section. A light signal falling on the light-receiving element where the consumable section is in absence, is passed in a suitable manner via a light wave guide to a furnace control which activates a safety system.

Abstract: To provide an axially variable means of fixation, an electrode for electric arc furnaces is held via a spacing means comprising radially movable contact elements and metallic spacers. The contact elements may be pressed radially inwards against the electrode by means of clamping jaws, thus constituting a solid mechanical and electrical contact between the electrode clamp and the electrode proper.

Abstract: An electrode for electric arc furnaces, comprising an upper, metallic, water-cooled section and a lower section of consumable material, such as graphite, is held in its given position by means of an electrode support arm 1,2. The connection elements for electric power and liquid coolant 12, 6, 25 are integrated in the electrode support arm and are designed as plug connections.