Abstract: When using oxygen gas pipes 3, situations can arise, in particular due to slag return and similar dangers, in which the operator must initiate safety measures. Slag return safety devices are known which, in such a case, ensure that the gas flow is stopped by melting a cap 35 of a heat sensor 5. The response of this outlet valve 6 of the slag return safety device can be recognized, for example, by the fact that the inlet pressure of the existing oxygen gas 4 is used to push pins 21 located in the wall 19 of the oxygen gas pipe 3 beyond the outside 27 of the oxygen gas pipe 3, so that they cannot be overlooked as a warning signal. The movement of the pins 21 can be used to activate further signal systems 30 in order to provide additional indications of this movement optically and/or acoustically.

Abstract: Systems and methods for measuring the level of a plurality of phases of a conductive or semi-conductive mixture in a vessel. The systems and method include a vessel configured to hold the mixture, a plurality of antennas configured to transmit electromagnetic and/or eddy current signals into the mixture to impinge upon the plurality of phases and to receive corresponding signals reflected from the plurality of phases, a transmitter module configured to generate electromagnetic and/or eddy current signals in communication with the plurality of antennas, a receiver module configured to receive electromagnetic and/or eddy current signals in communication with the plurality of antennas, a control module in communication with the transmitter module and the receiver module configured to control their operation, and a signal analysis module in communication with the receiver module configured to process the reflected signals to determine the levels of the plurality of phases within the vessel.

Abstract: An immersion nozzle used for measuring a level of molten metal, wherein a first conductive portion and a second conductive portion which are made of carbon are imbedded in a pair of slots which are provided on the surface of the immersion nozzle separately from each other and along the longitudinal direction in such a way that the first and second conductive portions form integral parts of the surface of the immersion nozzle.

Abstract: Disclosed is a heat treatment unit 4 serving as a heat treatment apparatus, which includes a chamber 42 for containing a wafer W on which a low dielectric constant interlayer insulating film is formed, a formic acid supply device 44 for supplying gaseous formic acid into the chamber 42, and a heater 43 for heating the wafer W in the chamber 42 which is supplied with formic acid by the formic acid supply device 44.

Abstract: Provided are an agitation device, a melting apparatus, and a melting method which achieve good melting efficiency without contaminating molten metal. The agitation device is provided with a traveling magnetic field generating unit which is disposed outside a charging tank for storing molten metal and generates, inside the charging tank, a magnetic field that travels downward along the rear sidewall of the charging tank, whereby a flow of the molten metal that rotates longitudinally about an axis approximately parallel to the surface of the molten metal is produced in the molten metal. By charging aluminum cutting chips into the molten metal in which the flow is produced, the aluminum cutting chips move with the flow of the molten metal, get into the molten metal roughly in the position where a downward flow of the molten metal is produced, and are immersed in the molten metal, and thus the melting of the aluminum cutting chips is accelerated.

Abstract: An experiment is conducted in advance, for finding a temperature of a cooling plate attained as a result of balancing between a temperature of a substrate after heat treatment and a temperature of the cooling plate at the time of cooling of the substrate. Then, before heat treatment of a first substrate, the cooling plate is moved to a position above a hot plate, the cooling plate is heated to that temperature, and thereafter heat treatment of the substrate is started.

Abstract: An apparatus is provided for determination of at least one interface of a slag layer on top of a molten metal. The apparatus has a carrier tube and a measuring head arranged on one end of the carrier tube with a body fixed within the carrier tube and an end face facing away from the carrier tube. The apparatus further includes an oscillator arranged within the measuring head and an induction coil connected with the oscillator and arranged outside of the body and in front of its end face.

Abstract: To degas a molten metal, a receptacle containing the molten metal and a layer of slag over the molten metal is positioned in a chamber, and the chamber is evacuated. As the pressure in the chamber reduces, gas is generated at the interface between the molten metal and the slag, which causes the slag to foam. To inhibit overflowing of slag from the receptacle, a gauge outputs a signal indicative of the level of the surface of the slag, and the rate of evacuation of the chamber is reduced to reduce the rate of gas generation.

Abstract: An apparatus for transferring molten metal from a melting furnace to a casting furnace is provided. A sensing and control system for the transfer of molten metal from a transfer furnace to a casting furnace is also described. The combination of the transfer apparatus with the sensing and control system provides for the introduction of reduced oxide molten metal into a casting furnace.

Abstract: A non-invasive online system for continuous measurements of phase levels in a converter or pyrometallurgical furnace in smelting and conversion processes, consisting in a electrical signal generator, transducers that convert said electrical signals in mechanical waves placed on the outer end of air blowing tuyeres, coupling means between said system and the shell of the converter, transducers placed in the direction of the axis orthogonal to the phases plane for applying mechanical waves that travel in a transversal direction into the converter, a mechanical waves sensor placed around the external wall of the shell of the converter that receives the reflected signal, a crystal local oscillator, means for the preamplification of the signal, an analogous/digital interface, a means for data acquisition, a means for processing the signals so as to determine the power of the reflected signal and the propagation time of the signal between the moment it is emitted by the transducer and the moment in which the reflec

Abstract: In a method of melting metal of a predetermined liquidus temperature, particularly a non-iron metal, such as magnesium, in a heated melting chamber into which solid metal is introduced and where a stream is generated, the parameters of flow are chosen such that the melting time is, in maximum, half the melting time without this stream under the condition that the temperature of the molten metal, when measured at at least one place in a distance of 5 mm in maximum from the solid metal, does not fall below liquidus temperature. To this end, an apparatus may be provided comprising at least one pump in a melting chamber having an associated heating device. This pump sucks the melt through at least one inlet opening and discharges the melt through at least one outlet opening. Both inlet opening and outlet opening are arranged within the melt bath of the melting chamber.

Abstract: An apparatus for transferring molten metal from a melting furnace to a casting furnace is provided. A sensing and control system for the transfer of molten metal from a transfer furnace to a casting furnace is also described. The combination of the transfer apparatus with the sensing and control system provides for the introduction of reduced oxide molten metal into a casting furnace.

Abstract: In a metallurgical vessel (1) having a tapping apparatus (5) for the slag-free withdrawal of liquid metal (3) from a molten metal bath (3) which is disposed in the vessel (1), a first leg (11) of a discharge duct (10) passes through the refractory vessel wall (15) and an overflow edge (14) in the connecting region of the two legs (11, 12) of the discharge duct (10) is higher than the upper edge (18) of the inlet opening (17) of the discharge duct. The molten metal (3) in the discharge duct is preferably inductively heatable.

Abstract: An apparatus and method for measuring the level of a free surface of molten metal in an electromagnetic continuous casting process using an AC electromagnetic field. A detection coil is provided to detect the sum of a magnetic field applied from an induction coil and an induced magnetic field based on eddy current in the molten metal. An arithmetic unit is provided to detect the surface level of the molten metal by removing a variation of the applied magnetic field with a variation in current to the induction coil from an output signal from the detection coil. The surface level of the molten metal can be accurately measured by determining whether a variation in the output of the detection coil results from a variation in the applied magnetic field or a variation in the surface level of the molten metal.

Abstract: A molten metal treatment furnace (10) with metal treatment and level control includes a heating chamber (12) for containing and heating a supply of molten metal (60), a pump (22) connected to the heating chamber (12), a molten metal treatment chamber (16, 18) located at the outlet of the pump (22), and a dosing chamber (40) located downstream and in fluid communication with the molten metal treatment chamber (16, 18). A trough (44) is connected to the dosing chamber (40) for supplying the molten metal (60) to a downstream process. A molten metal level sensor (66) is located in the dosing chamber (40). The pump (22) is a variable speed pump having a pump inlet (24) connected to the heating chamber (12) and configured to pump the molten metal (60) through the furnace (10) during operation. The molten metal level sensor (66) is connected to the pump (22) for providing a pump speed control signal to the pump (22).

Abstract: A dosing furnace (10) with metal treatment and level control includes a holding chamber (12) for containing a supply of molten metal (50), a pump (22) connected to the holding chamber (12), a molten metal treatment chamber (16, 18) located at an outlet (26) of the pump (22), and a dosing chamber (40) located downstream and in fluid communication with the molten metal treatment chamber (16, 18). A molten metal level sensor (56) is located in the dosing chamber (40). The pump (22) is a variable speed pump having a pump inlet (24) connected to the holding chamber (12) and configured to pump the molten metal (50) through the dosing furnace (10) during operation. The molten metal level sensor (56) is connected to the pump (22) for providing a pump speed control signal to the pump (22).

Abstract: A molten metal vessel includes a first chamber for containing molten metal such as molten aluminum therein, a filtration chamber in which impurities contained in the molten metal are removed, and a second chamber for reserving clean molten metal to be supplied to a casting die. The molten metal flows from the first chamber to the second chamber through the filtration chamber. A pair of filters, preferably a pair of cylindrical filters, are disposed in the filtration chamber, so that the impurities contained in the molten metal can be filtered twice. The filters are attached to the bottom of the filtration chamber where molten metal oxides hardly develop, so that the filters are easily replaced with new ones for the maintenance purpose. A rod-shaped heater may be disposed in the cylindrical filters to keep the molten metal temperature in a strictly controlled range. Thus, the impurities are effectively removed from the molten metal through the filters which are easily replaceable.

Abstract: The invention relates to a process for controlling casting parameters and in particular to the control of the metering of the molten metal in a casting chamber of a vacuum die-casting machine. Measurement devices connected to a computer determine the volume and condition of the molten material. An evacuation device and a vacuum valve are controlled in the form of a control circuit.

Abstract: A molten metal transfer pipe 52 for transferring an injection sleeve 51 has a bent pipe portion 3 thereof reduced in diameter to provide a throttle part 4 attaining a pressure loss effect. A melting and holding furnace 101 with a tilting mechanism has a melting and holding furnace section 101 and an electrical lifter 113 for holding the melting and holding furnace section 101 horizontally and for tilting the melting and holding furnace 101 together with a molten metal supplying apparatus 102 upwardly about the melting chamber 104 serving as a tilting fulcrum C to hold the same in the tilted position.

Abstract: An apparatus and method for indexing the slag-metal interface level in a metallurgical container uses an insulating refractory brick having a plurality of embedded conductor wires. Distal ends of the conductor wires are exposed at know, fixed distances from the distal end of the stick and flush with the brick face. The proximal ends of the conductor wires protrude a predetermined distance from the proximal end of the brick. The brick is attached to the inner lining of the container at a known distance from the floor of the container. The proximal wire ends are joined by a suitable connector to a signal-transmission cable containing a matching number of individual conductors, which is connected to a multi-channel voltmeter. Output from the multi-channel voltmeter can be input to a multiple-channel PC-based signal interpretation instrument. During operation the voltage output of each sensor circuit is continuously monitored.

Abstract: A molten metal vessel includes a first chamber for containing molten metal such as molten aluminum therein, a filtration chamber in which impurities contained in the molten metal are removed, and a second chamber for reserving clean molten metal to be supplied to a casting die. The molten metal flows from the first chamber to the second chamber through the filtration chamber. A pair of filters, preferably a pair of cylindrical filters, are disposed in the filtration chamber, so that the impurities contained in the molten metal can be filtered twice. The filters are attached to the bottom of the filtration chamber where molten metal oxides hardly develop, so that the filters are easily replaced with new ones for the maintenance purpose. A rod-shaped heater may be disposed in the cylindrical filters to keep the molten metal temperature in a strictly controlled range. Thus, the impurities are effectively removed from the molten metal through the filters which are easily replaceable.

Abstract: Radar is used to measure not only the level of slag on molten steel but also its thickness; the measurement is used to calculate the volume of slag, and, in turn the amount of additives for slag treatment. Time-of-flight data are used to identify peaks representing the distances of the surfaces of the slag and the surface of the underlying steel. The concept is applicable to other materials of differing composition, and particularly where the underlying material is relatively more conductive than the overlying material. Degassing is more efficiently practiced by using the radar slag thickness determinations to assist in vertical placement of snorkels.

Abstract: A method and apparatus for improved control of continuous electric arc furnace steelmaking in which a charge velocity detector measures charge velocity of metallic charge introduced to the furnace. A charge mass detector measures a charge mass of metallic charge introduced to the furnace. A computer determines a feed rate based on the charge velocity and the charge mass. An automatic bath level probe detects a steel bath. The computer determines a steel bath level and optimal positions to insert a temperature probe and an oxygen lance, and further predicts new bath levels from one tapping time to the next tapping time. The temperature probe is inserted to an optimal measurement position based on the steel bath level and measures a steel bath temperature. The oxygen lance is positioned and maintained at an optimal oxygen injection position and injects oxygen into the bath.

Abstract: Both an apparatus and method for measuring the depth of slag and molten metal contained in a tundish, ladle, electric furnace, or other vessel is provided. The apparatus includes a voltmeter for comparing the electrical potential of the steel, the slag-steel interface, and the air-slag interface to a ground potential, in combination with a probe member formed from a conductive material. The probe member has a proximal end that is electrically connected to the voltmeter, and a distal end movable between the vessel floor and one or the other of the interfaces. The apparatus further includes an articulated arm for positioning the distal end of the probe member in the vessel and across the molten metal so that it traverses at least one of the other two interfaces. The depth of the molten metal or slag is determined by noting differences in the electrical potential detected by the voltmeter while monitoring the vertical position of the distal end of the probe member in the vessel.

Abstract: A process for recovering Na from a spent NaS cell, includes the steps of forming an opening in a spent NaS cell, flowing down molten Na from an interior of the NaS cell through the opening in a heating oil vessel, passing the molten Na through a filter placed in the heating oil vessel to remove metallic powder, collecting the molten Na in a bottom portion of the heating oil vessel by utilizing a difference in specific gravity between the molten Na and an oil, and taking out the Na from an outer side of the filter.

Abstract: A molten metal supply device capable of supplying molten metal with high precision to an injection sleeve of a die-casting machine, and capable of reducing molten metal leakage and damage to a molten metal conduit bridging between a holding furnace and the injection sleeve. The holding furnace is divided into a holding chamber and a supply chamber in fluid connection with the injection sleeve through the conduit. Both chambers can be selectively brought into and out of fluid connection by a stopper. First and second immersion bodies are immersibly provided to the chambers, respectively. The laser sensor detects a predetermined level of the molten metal. The first immersion body is immersed until the sensor detects the surface of the molten metal, whereupon the stopper blocks fluid communication between the chambers. By then lowering the second immersion body, molten metal is pushed out of the supply chamber and a predetermined amount of molten metal is supplied to the injection sleeve.

Abstract: A device for the detection of a level of molten metal in a molten vessel, especially a dosing furnace, is proposed in which a sensor made of electrically conductive material and which emits a signal on contact with the molten metal, is inserted, electrically insulated, into the casing of the vessel of the riser pipe provided in the vessel and terminates substantially flush with the surface of the casing. In the casing there is thus a contact surface, the adhesion of metal and metal oxide to which is substantially excluded.

Abstract: Apparatus and method for determining when the depth of molten (18) poured into a vessel (12) has reached a selected level. A conduit (22) connected to a source of pressurized gas and having an orifice (43) at its distal end (38) restricts the flow of gas out of the conduit which is positioned at a selected level in the vessel. A drop in pressure in the conduit (22) resulting from escape of compressed gas when the distal end (38) is melted by the rising molten metal is detected and signalled to a visible, audible indicator or directly to an electronic controller to discontinue pouring of metal (18) into the vessel (12).

Abstract: A constant molten metal surface level retaining furnace is integrally provided with a melting unit which permits a space for equipment to be reduced to efficiently carry out transfer of molten metal. This furnace comprises, a heating unit (16) for heating a casting material to produce the molten metal, a furnace body having a molten metal treatment and storage chamber (18) for storing a molten metal after having undergone a predetermined molten metal treatment, and a molten metal retaining chamber (20) for storing the molten metal to be delivered to casting machine, which is partitioned from the molten metal treatment and storage chamber (18). A molten metal surface level control means is provided for conducting a control so that a molten metal surface within the molten metal retaining chamber (20) is maintained at a predetermined level.

Abstract: First and second electrodes are inserted into molten metal. A first pseudo random signal is transmitted to the first electrode, and at the same time the first pseudo random signal and a second pseudo random signal which has the same pattern as the first pseudo random signal but which is slightly different in frequency from the first pseudo random signal are multiplied by each other in a first multiplier to thereby calculate a first product value. A signal obtained from the second electrode and the second pseudo random signal are multiplied by each other in a second multiplier to thereby obtain a second product value. The displacement of the molten metal is calculated from the time difference between maximum correlation values respectively appearing in time series patterns of the first and second product values.

Abstract: A two-chamber furnace for delivering a melt to a casting machine comprises a storage chamber having an inlet device for material to be melted, a removal chamber having an outlet device for removing the melted material, and an intermediate chamber arranged between the storage chamber and the removal chamber, the intermediate chamber communicating with the removal chamber through a balancing port and with the storage chamber by an overflow. A control device controls the level of the melted material in the removal chamber, the control device including a pump for moving the melted material from the storage chamber to the intermediate chamber.

Abstract: A process and apparatus for producing a spray of atomized metal droplets includes providing an apparatus that forms a spray of molten metal droplets, the apparatus including a metal source and a metal stream atomizer, producing a stream of liquid metal from the metal source, and atomizing the stream of liquid metal with the metal stream atomizer to form the spray of molten metal droplets. A controlled spray of atomized metal droplets is achieved by selectively varying the temperature of the droplets in the spray of molten metal droplets, the step of selectively varying including the step of varying the flow rate of metal produced by the metal source, responsive to a command signal, and sensing the operation of the apparatus and generating the command signal indicative of the operation of the apparatus. The step of atomizing may be accomplished by directing a flow of an atomizing gas at the stream of liquid metal, and then selectively controlling the flow rate of the atomizing gas.

Abstract: Apparatus for producing a metal powder includes a cooled hearth structure in which a metallic alloy is melted and a heat source above the hearth positioned to heat the melt in the hearth. The cooling of the hearth causes a protective hearth skull to form between the melt and the hearth itself. The hearth is placed within an environmental control chamber. A supply structure provides a continuous supply of the metallic alloy to the hearth structure from the exterior of the chamber. A metal powder producer is positioned to receive molten metal from the hearth, and a continuous stream of the molten alloy from the hearth is transferred to the metal powder producer. The transfer is accomplished by tipping the hearth or by teeming through an opening in the bottom of the hearth. The hearth structure can utilize two individual hearths, controllably arranged so that molten metal is drawn from one hearth while the other is recharged.

Abstract: A method and apparatus are described for controlling the rate of pouring of molten metal. Examples are given of pouring metal onto a steel strip to form a coating having a uniform controlled thickness thereon. The method comprises the use of an intermediate holding dish having pouring means in the form of a generally vertical slot. The metal head presented to the slot is variable in response to signals from sensors measuring, for example, total strip thickness and the metal level within the holding dish. Signals from the sensors are also used to generate control signals to vary the rate of pouring from a holding furnace into the dish.

Abstract: A process and apparatus for producing a spray of atomized metal droplets includes providing an apparatus that forms a spray of molten metal droplets, the apparatus including a metal source and a metal stream atomizer, producing a stream of liquid metal from the metal source, and atomizing the stream of liquid metal with the metal stream atomizer to form the spray of molten metal droplets. A controlled spray of atomized metal droplets is achieved by selectively varying the temperature of the droplets in the spray of molten metal droplets, the step of selectively varying including the step of varying the flow rate of metal produced by the metal source, responsive to a command signal, and sensing the operation of the apparatus and generating the command signal indicative of the operation of the apparatus. The step of atomizing may be accomplished by directing a flow of an atomizing gas at the stream of liquid metal, and then selectively controlling the flow rate of the atomizing gas.

Abstract: A furnace system particularly adapted for use with a continuous upcaster. Instead of employing discrete furnaces, tundishes, ladles and the like, the instant unitary system employs a furnace, a feeding mechanism for directly introducing material into the furnace and a plasma torch to melt the material. The rate of material entering the furnace is balanced by the quantity of product emerging from the upcaster.

Abstract: According to this process: the position in respect of height of the "molten metal (2)/liquid slag (3)" interface (M) is continuously determined. Further the position of an isotherm (IS) located at the "liquid slag (3)/powder layer (4)" interface is continuously determined by automatically controlling the position of a thermocouple (8) on this isotherm and by measuring the displacements of this thermocouple.By comparing the position in respect of height of the molten metal/liquid slag interface (M) with the position in respect of height of the isotherm (IS), the thickness and thus the variations in thickness of the liquid slag are continuously deduced.

Abstract: A method and apparatus are described for controlling the rate of pouring of molten metal. Examples are given of pouring metal onto a steel strip to form a coating having a uniform controlled thickness thereon. The method comprises the use of an intermediate holding dish having pouring means in the form of a generally vertical slot. The metal head presented to the slot is variable in response to signals from sensors measuring, for example, total strip thickness and the metal level within the holding dish. Signals from the sensors are also used to generate control signals to vary the rate of pouring from a holding furnace into the dish.

Abstract: The invention provides a new stirring apparatus for stirring the liquid metal contents of a furnace, particularly the shallow furnaces used in the processing of aluminum and its alloys. The apparatus consists a reservoir separate from the furnace of relatively large horizontal cross-section and volume, into which a vaccuum draws metal from the furnace through a nozzle, the metal then being returned by gas pressure forcibly into the furnace through the nozzle in the form of a horizontally directed jet. The cycle is repeated at sufficiently close intervals to ensure that the furnace bath is quickly and effectively mixed. The nozzle directs the molten metal entering the reservoir tangentially to swirl the metal and reduce the accumulation of dross. The reservoir comprises a bottom static part including the nozzle and a readily removable top cover carrying heaters for heating the reservoir interior and the dross that deposits on the side wall to ease its removal.

Abstract: This invention relates to an electromagnetic molten metal supply system in a die cast machine and so forth, in which an electromagnetic pump is immersed in a furnace for maintaining molten metal, and the supply tube of the pump is connected to an injection cylinder. The electromagnetic pump is provided with two groups of coils, one of which is for maintaining the molten metal and the other group of coils for supplying the molten metal, and these two coils are controlled separately.

Abstract: A device for monitoring the level of molten metal in a converter comprises a .gamma.-radiation source, a .gamma.-radiation receiver connected to an input of an amplifier connected to a pulse amplitude analyzer, a timer, a molten metal level data display unit. The device for monitoring the level of molten metal in a converter also comprises a processor, a converter position transducer, an oxygen lance position transducer. The inputs of the processor are connected, respectively, to the pulse amplitude analyzer, to the timer, to the converter position transducer, and to the oxygen lance position transducer. The processor outputs are connected to the molten level data display unit and to the timer respectively.

Abstract: Device to measure the level of liquid metal in a crystallizer of a continuous casting ignot mould, the device employing a source of an electromagnetic field and providing for an emitter coil (17) and at least one receiver coil (18) and including the supply of the emitter coil (17) with at least one high frequency. The emitter coil (17) and receiver coil (18) being located inside a container (15) within the body of the ingot mould in cooperation with a cooling fluid conveyor (11) and being coupled electromagnetically to one single wall of the crystallizer (12) and to the volume within the crystallizer (12).

Abstract: The device has a lance. The lance is moved towards said molten bath level. An antenna is provided at a downward end of the lance for coaction with the slag interface (interfaces), when the lance is moved towards the slag interface (interfaces). A sensitive detection circuit is connected to said antenna. The antenna is during its downward movement capacitively coupled to said slag layer, and the detection circuit detects a predetermined impedance change (predetermined impedance changes) at the antenna provided as it is moved towards the interface (interfaces).

Abstract: A device for control of the pouring process in molds, wherein molten metal is adapted to be tapped from a vessel (e.g. a pouring furnace, a ladle or a tundish) provided with a stopper or other flow-control valve means. Between the vessel and the mold at least one transmitter coil and at least one receiver coil are positioned for measuring the degree of filling of the mold, suitably in a pouring cup. The output signal from the receiver coil is supplied to a signal processing device for control of the flow-control valve means.

Abstract: A method and apparatus for measuring the bulk temperature of a workpiece in a quenching apparatus. The temperature is calculated by monitoring the change in size of the bore in the workpiece.

Abstract: The invention relates to an apparatus for purifying lithium, formed by a sealed enclosure comprising a heated upper portion 1 provided with a container 9 in which the molten lithium 11 is agitated and from which the impurities evaporate, and a cooled lower portion 13 provided with a condensation surface 17 and a pipe means 16 for producing a depression in the lower portion. The invention is used in the purification of lithium, and in particular, for separation of lithium from sodium and potassium impurities.

Abstract: The device is to include a cylindrical carrier member for insertion into a tubular lance, also having an overhanging flange on the opposite side thereof being disposed a tapered electrode carrier either a cone with rounded apex or a symmetrical wedge with rounded apex and steep rounded sides.

Abstract: A molten metal filter effectiveness indicator comprising means for detecting the molten metal level on at least one side of a molten metal filter, and method.

Abstract: A two electrode probe is lowered into a vessel and the electrodes are electrically interconnected by liquid steel; the resistance condition then existing is ascertained as reference value against which subsequent resistance measurements are referenced as the probe is lifted from the vessel. The traversal of the slag-liquid metal interface causes a relative resistance change permitting selection of a threshold level that is independent from other measuring and operating parameters. The threshold device operates a counter in that for example forward and reverse counting tracks the lowering and lifting of the probe, but counting is halted when the interface level is reached, the count state then indicating the spacing of a zero level of the probe position from the level in which the threshold was exceeded in a particular direction.

Abstract: A metallurgical container has a refractory lining for containing a molten metal. A plurality of combination electrodes are provided at various positions of the refractory lining. Each combination electrode includes a refractory body having the property of high electrical conductivity at normal temperatures of the molten metal, and at least one electrical conductor embedded within the refractory body. Refractory material having a low electrical conductivity is positioned between the combination electrodes. A power source is connected to the electrical conductors of the plurality of combination electrodes to achieve first electrical resistances through the refractory bodies from the interior of the metallurgical container to the electrical conductors and second electrical resistances between the electrical conductors.