Abstract: An electric induction furnace for heating and melting electrically conductive materials is provided with a lining wear detection system that can detect replaceable furnace lining wear when the furnace is properly operated and maintained. In some embodiments of the invention the lining wear detection system utilizes an electrically conductive wire assemblage embedded in a wire assemblage refractory disposed between the replaceable lining and the furnace's induction coil.

Abstract: The present invention relates to damage detection systems for refractory linings for molten metal vessels, comprising an electrically conductive grid disposed underneath the surface of the refractory lining closest to a molten metal when in use, one or more electrically conductive electrodes disposed in contact with the molten metal when in use and an electrical power source, wherein the electrically conductive metallic grid and the one or more electrically conductive electrodes are electrically connected to each other, such as to form an open electrical circuit powered by the said electrical power source, and a detected closure of the said electrical circuit during normal use of the molten metal vessel indicates that the said refractory lining is damaged, or the presence of a molten metal during normal operation of the vessel closes the said electrical circuit in case the refractory lining is damaged.

Abstract: An electric induction furnace for heating and melting electrically conductive materials is provided with a lining wear detection system that can detect replaceable furnace lining wear when the furnace is properly operated and maintained.

Abstract: An electric induction furnace for heating and melting electrically conductive materials is provided with a lining wear detection system that can detect replaceable furnace lining wear when the furnace is properly operated and maintained.

Abstract: An induction heating apparatus includes a measurement device for indicating an electrical resistance of a material to be heated. A controller is configured for energizing an inductor in response to the indicated resistance. An inductor may be energized with an alternating current, a characteristic of which may be selected in response to an indicated electrical resistance. Alternatively, a temperature of the material may be indicated via measuring the electrical resistance thereof and a characteristic of an alternating current for energizing the inductor may be selected in response to the temperature. Energizing the inductor may minimize the difference between a desired and indicated resistance or the difference between a desired and indicated temperature. A method of determining a temperature of at least one region of at least one material to be induction heated includes correlating a measured electrical resistance thereof to an average temperature thereof.

Abstract: An induction melting furnace includes a detection system for sensing metal penetration into a wall of the furnace depending upon detecting heat flow from the hearth to the furnace. The furnace includes a crucible including a refractory lining for holding molten metal, a coil for inductively heating the molten metal, and a power supply for supplying energy to the coil and the detection system. An electrode system is interposed between the coil and the lining comprising a sensing mat housing conductors receiving a test signal from the power supply, wherein the sensing mat includes a temperature sensitive binder that varies conductivity between the conductors in response to heat penetration through the lining. The sensing mat is preferably comprised of flexible phillosilicate mica for enhanced thermal conduction and the binder comprises an organic resin compound which carburizes at a predetermined elevated temperature.

Abstract: An alloying system for a galvanized steel sheet, using an induction heating coil, wherein the temperature of the steel sheet in an induction heating furnace is measured based on the impedance of a high frequency heater, and the amount of heating is controlled by feedback, to form an alloy layer of the steel sheet.

Abstract: A melt guide is provided for enclosing a bottom of an electroslag refining crucible containing a melt of electroslag refined metal. A base plate is sized to have a perimeter to engage the crucible bottom for attachment thereto. The base plate includes an upper surface for defining with the crucible a reservoir for receiving the melt, and a lower surface spaced therebelow. A central drain extends through the base plate for draining by gravity the melt from the reservoir. A plurality of circumferentially spaced apart slots extend radially outwardly from the drain toward the base plate perimeter and extend vertically through the base plate. Induction heating coils are mounted below the base plate lower surface for heating the melt through the slots. The base plate may take various forms including a flat plate, with or without a cooperating and removable insert.

Abstract: Temperature sensors are embedded in a refractory material that make up the walls of a body of an induction furnace and detect an increase in the temperature of a molten metal in the body of the furnace due to the bridging of a metal material that is to be melted in the furnace body. The temperature sensors are connected to an antenna for detecting runout. Since various electrical data (voltage, current, power, frequency, etc.) that affect an alternating current to be supplied to a coil of the induction furnace change depending on the temperature of the molten metal, bridging of the metal material is detected by determining the rates of temporal change in these electrical data. Furthermore, the changes in the electrical data with respect to the progress of the operation of the induction furnace are previously stored in data storage, and the electrical data stored are compared with electrical data detected in the induction furnace in operation.

Abstract: In order to determine the contents of solids in a heated elongated slug of thixotropic metal having a longitudinal axis, there is an apparatus comprising an inductive heating coil with electrical winding. Moreover, a sensor includes at least one measuring coil arranged between the heating coil and the slug. This sensor provides an output signal which corresponds to the contents of solids demanded.

Abstract: A metal material such as scraps of metal is directly heated by electromagnetic induction, and the resulting molten metal is fed to a heatup zone where the molten metal is further heated to a required temperature. More specifically, the metal material to be melted, which has been charged into a heat and melt zone, is preheated and melted by an induction coil, and the molten metal is passed via a connection portion to the heatup zone, and is stored there. The thus accumulated molten metal is further heated by an induction coil to a necessary temperature. The molten metal is taken out of the furnace by opening a tap hole when this is desired. Various kinds of gases can be selectively introduced into the apparatus via an gas inlet. By keeping the tap hole in an open condition, the molten metal can be continuously taken out of the furnace. With the induction heating method which has heretofore enabled only an intermittent melting operation, the metal material can be continuously melted and taken out.

Abstract: Temperature sensors are embedded in a refractory material that make up the walls of a body of an induction furnace and detect an increase in the temperature of a molten metal in the body of the furnace due to the bridging of a metal material that is to be melted in the furnace body. The temperature sensors are connected to an antenna for detecting runout. Since various electrical data ( voltage, current, power, frequency, etc.) that affect an alternating current to be supplied to a coil of the induction furnace change depending on the temperature of the molten metal, bridging of the metal material is detected by determining the rates of temporal change in these electrical data. Furthermore, the changes in the electrical data with respect to the progress of the operation of the induction furnace are previously stored in data storage, and the electrical data stored are compared with electrical data detected in the induction furnace in operation.

Abstract: Nuclear fuel rod tubes of zirconium alloy are heat treated in an induction furnace to produce a protective oxide coating two to fifteen microns in thickness. The furnace is only slightly larger than the tubes and receives the endmost eight inches of the tube. The furnace is controllable in zones along the tube. To calibrate the furnace to produce the desired temperature profile, typically a flat profile at a temperature between 650.degree. and 750.degree. C..+-.1.5.degree. C., a temperature calibration probe is provided with spaced thermocouples for sensing the temperature developed in the probe at each of the zones when heated. The probe is made of inconel 600 stainless or the like, and is dimensioned and shaped to correspond closely to the dimensions of the fuel rod tubes, including having a closed chamfered end. At the opposite end the probe protrudes from the furnace, where the thermocouple leads are terminated. The leads pass through a potting compound in the probe, such as magnesium oxide.

Abstract: A prewarning device for an induction melting furnace serves for warning of breakouts of molten metal on ceramic furnace linings of melting furnaces. The device has electrodes that may be arranged on the furnace lining in question which are divided into two groups of different polarity and are spaced apart from each other. The electrode groups can be connected to an evaluation unit in order to determine the electrical temperature-dependent resistance of the furnace lining. In order to permit a simple application of the electrodes on the outside of the furnace lining and assure a high reliability of indication of the entire system, at least a high reliability of indication of the entire system, at least one of the electrodes is arranged as an electrode network on a first side on a ceramic foil. Either the first side of the ceramic foil or the opposite side is arranged on the furnace lining.

Abstract: A crucible induction furnace is disclosed which is provided with a preventive measure against low melting point metals and having a crucible refractory within an induction coil in a barrel container, in which the crucible induction furnace comprises a coil protection member located between the crucible refractory and the induction coil and which includes at least one air-permeating portion. An air supply pipe is in communication with the air-permeating portion for supplying pressurized air to the crucible refractory. The air permeating portion is disposed to distribute pressurized air having a higher pressure adjacent to the bottom portion of the crucible refractory than to the upper portion of the crucible refractory.

Abstract: An induction furnace is disclosed, including a porous furnace wall formed by sintering castable refractory material. Gas passageways are formed in the furnace wall, and a common pipe connecting the gas passageways is connected to a gas conveying unit provided outside of the furnace wall. An outer gas-blocking layer surrounds the furnace wall.

Abstract: Disclosed is a method for measuring the extent of slag deposit buildup in the channel of a channel induction furnace during operation. The method comprises measuring an initial temperature rise factor in the furnace at a time when no slag deposits are present, measuring a subsequent temperature rise factor in the furnace after the furnace has been in operation for a period of time, correcting the subsequent temperature rise factor for any changes in the operating temperature and power levels applied to the furnace which may have taken place between the time of the measurement of the initial temperature rise factor and the time of the measurement of the subsequent temperature rise factor, and determining a quantity which is indicative of the extent of slag deposit buildup in the channel from the difference between the initial and subsequent temperature rise factors.