Abstract: A method and a device for closed-loop control of an electrode gap in a vacuum arc furnace subjects an electrode gap of a melting electrode from the surface of a melt material to closed-loop control as a function of a droplet short-circuit rate. For this purpose, a histogram of detected droplet short-circuits is created on the basis of at least one droplet short-circuit criterion. The histogram is subdivided into sub-areas, a characteristic sub-area of the histogram is selected for closed-loop control purposes. The electrode gap is subjected to closed-loop control on the basis of the droplet short-circuits which can be associated with the selected sub-area.

Abstract: A sealing device is arranged around a rod electrode extending vertically through an aperture made in the ceiling of an arc furnace and being vertically movable inside the furnace to prevent the access of gases from the furnace through the aperture to the atmosphere, and on the other hand to prevent air from flowing from the atmosphere into the furnace. The sealing device comprises a gas distribution chamber provided with an inlet channel for feeding essentially passive gas, such as nitrogen or air, into the gas distribution chamber. The sealing device also includes a slit nozzle encasing the electrode, through which nozzle a gas jet is arranged to be discharged from the gas distribution chamber towards the electrode in a direction that is at an angle with respect to the horizontal plane and has a slightly upwards inclined orientation, and that is, with respect to the furnace interior, pointed outwardly, so that the sealing is carried out owing to the effect of the created stagnation pressure.

Abstract: A method is provided for output control of a pulse width modulated power inverter used with a substantially resistive, single phase, ac load such as an electro-slag remelting furnace. In one application of the method, during each of the inverter's half cycle outputs, active switching devices are alternatively pulsed on and off during the half cycle so that only half of the switching transients in the half cycle are handled by one of the active switching devices.

Abstract: A lifting apparatus for transporting a carbon based electrode having a threaded male end. The apparatus includes a casing having a top end and a bottom end. The casing defines an electrode aperture from the bottom end shaped to accept the threaded male end of the carbon based electrode to secure the lifting apparatus to the electrode. An attachment aperture is positioned in the top end while an attachment element is positioned in the attachment aperture and operatively engaging the top end of the casing. The attachment element is positioned to accept engagement from a crane or other powered lifting device, while the lifting apparatus is preferably manually attachable to the electrode.

Abstract: A lifting apparatus for transporting a carbon based electrode wherein the electrode includes a threaded male end. The apparatus comprises a casing having a top end and a bottom end, a top plate operatively attached to the top end, at least one energy absorbing element positioned between the top plate and the top end, and an attachment element operatively engaging the energy absorbing element and the top end. The casing defines an electrode aperture in the bottom end shaped to accept the threaded male end of the carbon based electrode.

Abstract: The aim of the invention is to improve the cooling of the bottom electrodes (1) of metallurgical melting vessels. To this end, a cooling plate (5) is situated beneath the support plate (2) on which the contact elements (3) are supported. The cooling plate is set apart from the support plate. This forms a cooling chamber (4) through which a cooling medium flows, the cooling effect of said medium being reinforced by cooling ribs (6). Said cooling ribs are situated in the cooling chamber (4) and are welded to the support plate (2) and preferably, also to the cooling plate (5).

Abstract: A bottom electrode of a direct current electric arc furnace includes an electrode body extending through a hole defined in a bottom of the furnace. A circumferential flange is formed around a lower portion of the electrode body to which a ring connection member is attached. The connection member forms a ring channel defined by inner and outer walls from which inner and outer flanges radially extend in opposite directions. The inner flange is fixed to the circumferential flange of the electrode body by bolts. The outer flange is fixed to the furnace bottom for attaching the bottom electrode to the furnace bottom. The channel is located between the circumferential flange of the electrode body and an inside diameter of the hole defined in the furnace bottom for increasing radial distance between the electrode body and the hole of the furnace bottom. Insulative members are arranged on and under the circumferential flange of the electrode body for electrically isolating the electrode from the furnace bottom.

Abstract: A consumable electrode is suspended by a stub. The stub includes upper and lower hangers between which is vertically mounted a loadcell for weighing the electrode attached to the lower hanger. An electrical conductor is joined between the upper and lower hangers for carrying electrical current therebetween to power the electrode without damaging the loadcell.

Abstract: A scrap-melting electric arc furnace operating at an elevated melting power having a simple construction that also avoids thermal loads of the side wall caused by the electrodes. The electrodes are protected from damage during scrap-charging. The electric arc furnace includes a bottom for receiving a melt. An upper part rises from the bottom part and has side walls. A lid covers the upper part. A charging shaft is disposed approximately centrically relative to the upper part, and has a diameter that is substantially smaller than the diameter of the upper part. The charging shaft interior communicates with the furnace interior via an opening in the lid. Electrodes arranged approximately radially symmetrically are directed obliquely into the furnace interior and project toward the center of the electric arc furnace.

Abstract: A submerged arc furnace with an open slag bath, having a vertically movable frame which is arranged above the furnace which is closed by a cover. An electrode mount and an electrode filling device are arranged on the frame. A platform is provided on which the frame is supported via at least three regulating cylinders. The platform, which is arranged above the furnace cover, is configured as a maintenance platform on which, for each electrode, there is provided a sealing unit which has components for the horizontal and vertical sealing of the free surfaces between the electrodes and the electrode passage openings of the cover.

Abstract: A support for a melting electrode used in a glass melting bath. The support includes concentric tubes which provide for the circulation of a cooling fluid within the support. A current is provided through the outer tube to the electrode. The surface of the outer tube is electrically insulated and may be protected by a second cooling system outside the electrical insulation.

Abstract: A metallurgical container of the type having a vessel having a bottom wall and an inner refractory lining includes a hearth bottom electrode extending through the bottom wall and the lining and including, in a superposed condition, a bar and a connector. The bar is flush with the surface of the refractory lining. The connector is fastened to a lower surface of the bar, is internally cooled, has a diameter smaller than the diameter of the bar, and is attached to the bar at its upper front face at a level within the thickness of the refractory lining. A ring is interlocked to the vessel wall, surrounds the connector, and has an upper face located below the bar so as to be capable of carrying the bar. In order to prevent liquid materials from penetrating by infiltration between the bar and the ring, the bar is prolonged or elongated toward the bottom wall by a skirt which surround the connector laterally. The invention is particularly applicable to direct current operated steel plant arc furnaces.

Abstract: An electrode support arm for arc furnaces which is constructed as a hollow section with a wall formed at least partially from current-carrying material of high conductivity. The wall of the hollow section has a coolant guiding system including ducts arranged in the wall so as to be parallel to one another and concentric to the center axis of the support arm. The quantity and dimensions of these ducts enable sufficient cooling without a reduction in the strength of the support arm.

Abstract: A remelting furnace has a crucible and a raisable pot placed thereon. An electrode rod leads into the pot through a passage sealed by means of a seal carried by a lower platform. The lower platform is connected to the pot by a hitch having free play, and can be raised together with the electrode rod by a lift means supported on a weighing platform. In this manner weighing of the electrode rod uninfluenced by the friction forces of the seal is possible. Also, it is possible to lift the pot without increasing the structural height of the structure accommodating the remelting furnace.

Abstract: A remelting furnace has a crucible (2) and a raisable pot (3) placed thereon. An electrode rod (6) leads into the pot (3) through a stuffing box (8) borne by a lower platform (9). The lower platform (9) is carried by rods (12, 13) which are fastened each at its upper end to a weighing platform (14). The connection of the lower platform (9) to the particular rod (12, 13) is performed in each case through a releasable clutch (10,11 ). Consequently, a lifter (17) can lift the pot (3) such that it shifts upwardly with the bottom platform (9) relative to the rods (12, 13).

Abstract: An electrode carrier arm for an electric arc furnace consists of an arm part (10) and of a electrode-clamping device and is produced so as to be current carrying from a material of high conductivity. Between the arm part and the electrode-clamping device there is a flanged connection consisting of flanged plates (11, 12) which limit a cooling-liquid cavity (20, 29) on both sides and which themselves contain passage orifices (21) for the cooling liquid from one cooling-liquid cavity to the other. This allows an effective cooling of the flanged plates and consequently a direct supply of current via the flanged connection when the carrier arm is produced from light metal.

Abstract: A sealed connection for a sleeve and jacket for protecting a molybdenum electrode mounted through the wall of an electric glass furnace. Around the electrode in the wall is a stainless steel sleeve coated on the inside with a fused alumina and having an outwardly extending flange at its outer end which engages the outer wall or shoulder in the aperture in the wall through which the electrode extends. The flange has an axially outwardly extending rib of V-shaped radial cross-section which seats and centers in an annular V-shaped groove around the inner end of a water jacket that surrounds the electrode outside the furnace. Refractory sealing gaskets are placed between the flange and the wall of the furnace and in the cooperating grooves and ribs of the sleeve and water jacket. The sealed cylindrical annular space around the electrode between it and the sleeve and the jacket is filled with nitrogen to prevent oxidation of the molybdenum electrode.

Abstract: An electric furnace for melting batch material and mixing the molten material. Electrodes are used to create what is believed to be electromagnetically stirred active melting areas within the molten material. The molten material is stirred by moving the electrodes and furnace shell with respect to each other while the electrodes are positioned in a corona discharge relationship to the melt. This can be implemented by rotating the electrodes or the shell or by a compound movement caused by moving the electrode support arms toward and away from the center of the vessel in timed relationship to pivotal movement of electrode support arms so as to cause the electrode tips to traverse an arcuate path concentric with the center of the vessel. In a shallow immersion, simple pivoting of the electrode support arms is beneficial. To further decrease the dead area within a furnace vessel utilizing electrodes which are shallowly immersed, the vessel can be made polygonal as opposed to circular in lateral cross section.

Abstract: An apparatus for adjustably supporting a vertical electrode for an arc-type furnace. The apparatus includes an upper stationary electrode clamping structure and a lower adjustable electrode clamping structure suspended from the upper structure by adjustment screws. The two clamping structures are mounted on a carriage movable linearly into and out of registry with the furnace to accommodate maintenance and repair. Each clamping structure comprises an arcuate electrical contact and wedge-type slips engaging the periphery of the electrode in opposition to the electrical contact, the slips being spring-biased into electrode engagement and cam actuated from electrode engagement. The cams are actuated by a common shaft extending between the two clamping structures, so that the electrode is released from one clamping structure when engaged by the other clamping structure.

Abstract: An electrode support mechanism and method for use in electric arc melting or smelting furnaces wherein a pair of horizontal, superimposed arms are each provided with clamping devices at their outer end for supporting and supplying electric power to a vertically disposed electrode depending into an arc furnace. The arms are each supported on a vertical support post; the upper arm is fixed to the post and the lower arm which normally carries the electrode is movable relative to the post to adjust the electrode to maintain a constant arc at the furnace. The movable arm is moved vertically by a jack screw carried by the upper arm and depending into contact with the lower arm. The clamping devices at the ends of the arms are spring-biased toward contact with the electrode, and a linking mechanism is provided to alternately release the arm clamping mechanisms from the electrode under the control of an actuating system utilizing fluid pressure actuated cylinders.

Abstract: An electrode support mechanism for use in electric arc melting or smelting furnaces wherein a pair of horizontal, superimposed arms are each provided with clamping devices at their outer end for supporting a vertically disposed electrode depending into an arc furnace. The arms are each supported on a vertical support post; the upper arm is fixed to the post and the lower arm which normally carries the electrode is movable relative to the post to adjust the electrode to maintain a constant arc at the furnace. The movable arm is moved vertically by a jack screw carried by the upper arm and depending into contact with the lower arm. The clamping devices at the ends of the arms are spring-biased toward contact with the electrode, and a linking mechanism is provided to alternately release the arm clamping mechanisms from the electrode under the control of a cam-operated actuating system.

Abstract: An electro-slag remelting furnace having consumable electrodes and a mold for receiving a melt formed from the electrode material; at least one drive motor and at least one spindle and an associated stationary spindle nut for vertical movement of the electrode; at least one guide column, which is provided for vertically guiding the consumable electrodes and which extends parallel with the spindle and relative to which the spindle is rotatable mounted at its two ends; and at least one clamping device for the consumable electrodes.

Abstract: An electrode clamping device in an electroslag remelting plant has an adjustment device which defines two pivot axes for the electrode holding member which are aligned at right angles to one another and which can be independently controlled for effecting pivotal movement of the electrode holding member about the two axes.