Abstract: A Vacuum Arc Remelting controller apparatus wherein process control is accomplished primarily through control of pool power. Pool power being defined as the total energy flux into a top ingot surface of the VAR ingot. The controller apparatus of the present invention comprises a controller computer that transmits commands to the host furnace through an ethernet connection.

Abstract: The invention relates to an electronic circuit and a method for feeding power to at least one electrode of an alternating-current electric-arc furnace, particularly for melting metal. Known circuits of this type typically comprise a series connection with a transformer for providing a supply voltage for the electric-arc furnace from a power grid (1) and a AC power controller (8) connected between the transformer (6) and the electrode (11) for regulating the current through the electrode (11). According to the invention, a further development for such electronic circuits is proposed, which development has a simple design, is inexpensive and prevents overload of the AC power controller (8) even in operating modes of the electric-arc furnaces at high electrode currents. This further development provides to bypass the AC power controller with a bypass switch (9) that is opened or closed with the help of a controller as a function of the amount of current flowing through the electrode (11).

Abstract: An apparatus for and method of controlling a remelting furnace comprising adjusting current supplied to an electrode based upon a predetermined pool power reference value and adjusting the electrode drive speed based upon the predetermined pool power reference value.

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 method for producing metal ingots or billets, especially from steels and Ni- and Co- base alloys, by melting off consumable electrode in an electroconductive slag bath using alternating or direct current in a short, downwardly opening, water-cooled mould through which a current contact can be established with the slag bath. The melting current is introduced into the slag bath through the consumable electrode and through the mould in a controlled manner in terms of regulating the distribution of the current between the electrode and the mould; and is conducted back through the mould and the block and the base plate at option; the division of the currents being adjustable in a controlled manner. The proportion of the overall melting current delivered that is delivered via the consumable electrode can be chosen from between 0 and 100%.

Abstract: A bottom pour electroslag refining system refines raw material into refined liquid metal. The bottom pour electroslag refining system comprises an electroslag refining crucible; a slag; a bottom pour structure that comprises an orifice from which refined liquid metal from the electroslag refining crucible can flow as a stream of refined liquid metal; and a current path. The current path is defined in the bottom pour electroslag refining system for applying current to the raw material for melting and refining the raw material. The melted and refined raw material forms a refined liquid metal pool in the electroslag refining crucible. The current that is applied by the current path is sufficient to provide the refined liquid metal in the refined liquid metal pool with a viscosity under which the refined liquid metal can flow through the orifice under its own viscosity.

Abstract: A power source for an arc furnace having an intermediate circuit transformer including a magnetic decoupled booster transformer and an AC main-driven converter. Such a power source comprises a current controller and a zero voltage switch. The current controller and the zero voltage switch are integrated in the intermediate circuit transformer. The zero voltage switch short-circuits the main reactance of the booster transformer whenever the current controller faces a current cut off and is blocked.

Abstract: Procedure for regulating the heating of a furnace implementing a conventional means of regulation and a fuzzy logic supervisor which, on the basis of the given situation and the information which it receives on its inputs, adapts the parameters of the regulator, wherein the procedure includes the following steps:detection of the state of the process to be controlled and regulated;transient state or steady state is selected depending on the instructions/measurement discrepancy;selection of a control algorithm on the basis of the state (transient state or steady state) with the aid of a toggle based on the principle of fuzzy logic, while ensuring a smooth changeover between the states, with no discontinuity of control; andcalculation of the parameters of the regulator on the basis of the specific requirements, taking into account the following factors: volume production and rate of production, i.e., of the mass of the products treated in the furnace and of the speed of production; and temperature of the charge.

Abstract: In an electric arc furnace having a power source for applying at least one AC/DC voltage to at least one electrode, and the electrode being spaced apart from a grounded container for receiving scrap metal, wherein the application of the at least one AC/DC voltage to the at least one electrode causes generation of an arc between the electrode and the container for melting the scrap metal, a predictive line controller comprising a plurality of AC switches intermediate the power source and the electrode, and a central controller for monitoring the at least one AC/DC voltage and generating a signal model thereof, and in response generating and applying a plurality of gating signals to the plurality of AC switches, the gating signals being delayed by respective predetermined amounts based on the model, for causing the plurality of AC switches to gate the at least one AC/DC voltage in accordance with the model so as to minimize flicker in the electric arc furnace.

Abstract: A system for controlling electrode gap in an electro-slag remelt furnace has a constant regulated voltage and an eletrode which is fed into the slag pool at a constant rate. The impedance of the circuit through the slag pool is directly proportional to the gap distance. Because of the constant voltage, the system current changes are inversely proportional to changes in gap. This negative feedback causes the gap to remain stable.

Abstract: Methods and apparatus for treating waste with radio frequency include a wall defining a radio frequency treatment chamber through which waste may be passed. A source of radio frequency energy energizes the radio frequency treatment chamber to heat the waste and drive off vapors therefrom leaving solid residue to be disposed of. A guard heater and/or insulation maintains the wall at substantially the same temperature as the waste being heated by the radio frequency to prevent vapors from condensing on the waste.

Abstract: Two DC electric arc furnaces are provided side by side. The both DC electric arc furnaces are connected by a duct. Each of two power source apparatuses is mounted near and associated with each of the DC electric arc furnaces. The anodes of the both power source apparatuses are mutually connected by an anode cable and the cathodes of the apparatuses by a cathode cable. The anodes and the cathodes of the both DC elecric furnaces are connected to the anode cable and the cathode cable, respectively, via a connection circuit adapted to supply electric power alternately to either of the DC electric arc furnaces. When a raw material is molten in one of the DC electric arc furnaces, electric power is supplied by the both power source apparatuses to this DC electric arc furance. The exhaust gas at a high temperature produced in this DC electric arc furnace is sent to the other DC electric arc furnace through the duct and preheats another raw material charged there beforehand.

Abstract: In a direct-current arc furnace having a bottom electrode (2), electromagnetically and/or chemically induced bath agitations are substantially eliminated by an electromagnet (9) arranged under the vessel bottom (7). In this way the stability of the bottom electrode (2) is considerably increased. The electromagnet (9) is preferably integrated into the electrical supply of the furnace and serves as a smoothing choke.

Abstract: According to this process and this device:a signal representing the derivative of the intensity of the current in the arc is sensed,the sensed signal is amplified,the amplified signal is directed simultaneously into two band pass filters (6, 7) respectively having a high frequency broad band (6) and having a narrow band centered on a low fundamental frequency (7),the signals emanating from the filters (6, 7) are transmitted to effective value extractors (8, 9),by means of a divider module (11) an energy signal is formulated, which is proportional to the ratio of the effective value of the signal emanating from the broad band filter (6) and the effective value of the signal emanating from the narrow band filter (7),and the proportional energy signal obtained is displayed on a scale (12), where it is expressed as a percentage, this percentage being indicative of the behaviour of the arc, signifying the formulation phase.