Abstract: A method for controlling a melt process in an arc furnace and signal processing component, program code, and data medium for performing said method are provided. According to the method, sound signals or vibrations from the interior of the furnace container are captured by solid-borne sound sensors, from which characteristic values can be derived for the distribution of melting material, melt, and slag in the furnace fill. A characteristic value SM for thermal radiation impinging on the furnace wall of the container, a characteristic value M for the lumpiness of the melting material in the volume of furnace fill, and a characteristic value MM for the change to the portion of solid melting material contacting the furnace wall are generated in priority sequence. The energy distribution at the electrodes is changed by a control system analyzing the characteristic values in priority sequence, such that thermal load peaks are dampened or even completely prevented.

Abstract: The invention relates to a filter device (1) and a filter element (8) for cleaning an air stream that is charged with particles. The filter element (8) comprises a bag-type filter sock (17) consisting of an air-permeable, flexible material and a support body (21) in the interior of the bag-type filter sock (17). The first axial end of the bag-type filter sock (17) is closed and the second axial end has an air outlet that allows the cleaned air stream to exit the filter sock (17).

Abstract: In a melting furnace, a vibration inducer is installed on a furnace vessel, a sensor is arranged opposite or at another place on the furnace vessel and a signal recording and calculation unit is connected to the vibration inducer and the sensor. The melting process can be monitored and the progress of melting can be measured by measuring the signals of the vibration inducement after having passed through the interior of the furnace by this sensor and evaluating the signals of the signal recording and calculation unit. Thus, process-controlled, state-oriented regulation of the melting process can be carried out and the electric arc power is optimally matched to the respective state of the melting process. The signal of the sensor is preferably correlated with the excitation signal of the vibration inducer and/or conclusions are drawn about the melting process by combined evaluation of the vibration inducement and the measured vibration.

Abstract: In a method for operating an arc furnace (2) with at least one electrode (3a, 3b, 3c), a solid material fed to the arc furnace (1) is melted by an arc (1) formed by the at least one electrode (3a, 3b, 3c). A measurement (MM) for the mass of one part of the solid material arranged on a boundary (2) of the arc furnace (1) is determined, and using the determined measurement (MM), a process variable of the arc furnace (1) is controlled and/or regulated. A method which can reduce the risk of electrode damage caused by metal scraps falling into the treated area is provided.

Abstract: In a method for determining the size and shape value (M) for a solid material (S), in particular scrap metal, in an arc furnace (1), an electrode flow fed to an electrode (3a, 3b, 3c) for forming an arc furnace (L) between the electrode (3a, 3b, 3c) and the solid (S) is measured (30) and from the measured electrode flow (I (t)), an effective measurement value of the electrode flow is determined (31) and from the measured electrode flow (I (t)) (32), a flow part associated with a frequency range of the measured electrode flow is determined (32), and a quotient of the flow part and an effective measurement value is formed as a measurement of the shape and size value of the flow (M). Thus, a method is provided that enables a property of a fusible element introduced into one of the arc furnaces to be determined.

Abstract: In a method, a variable characterising an operational state of an electrode of an arc furnace can be determined. An electrode flow guided to the electrode is detected in the method and the structure-borne noise oscillations are detected. From the detected electrode flow, a flow evaluation signal associated with the frequency range of the detected electrode flow is determined. From the detected structure-borne noise oscillations, an oscillation evaluation signal that is associated with a frequency range of the detected structure-borne noise oscillations is detected and a quotient from the oscillation evaluation signal and the flow evaluation signal is formed as a radiation measurement for at least one frequency common to the detected electrode flow and the detected structure-borne noise oscillation.

Abstract: The invention relates to a method for operating a melt-metallurgic furnace (2), particularly an arc furnace, during the operation of which a number of operating parameters are maintained within predetermined thresholds, wherein for this purpose a control or regulating device (1) is utilized. In order to obtain greater efficiency of the furnace, the invention provides that the control or regulating device (1) has a conventional control or regulating device (9) and a fuzzy regulating device (10), which each feed their correcting variables to a mediator (11), wherein the mediator (11) calculates the actuating signal used according to a predetermined weighting factor (F) from the correcting variable coming from the conventional control or regulating device (9) and from the fuzzy regulating device (10). The invention further relates to a melt-metallurgic furnace, particularly an arc furnace.

Abstract: The novel method and device provide for process control—closed-loop control or open-loop control—for a thermal system with an obstruction-curved and/or thick-walled component through which a medium flows. The wall temperatures of the component are detected, the heat flux density of the heat flux from the medium into the wall of the component is determined, the respective heat transmission coefficient is determined, using the wall temperatures. The heat flux density, and the heat transmission coefficient thus determined are used to influence the medium properties, with the heat stresses in the component being taken into account.

Abstract: A method for producing a printed circuit, including at least the following steps: feeding different colloid inks to different printing nozzles of at least one print head, the colloid inks each containing a printing carrier and particles of a basic substance; printing individual droplets of the different colloid inks onto a substrate surface of a substrate between printed circuit traces in such a way that the droplets intermix to form a resistance layer; and baking the substrate having the printed circuit traces and the imprinted resistance layer in such a way that the printing carrier is at least substantially removed. The resistors can therefore be printed quickly, advantageously in one run of the print head. A suitable square resistance value can be set for each resistor by appropriate dosing of the individual colloid inks, so that the surface requirement on the substrate is small.

Abstract: An open-loop and closed-loop control method is described for starting up or shutting down a process component of a technical process. At least one manipulated variable that is fed to the process is formed by a control device and an upstream model-assisted pilot control. The pilot control contains an optimizer and a process model. The optimizer is fed at least one command variable for the technical process. At least one optimized model manipulated variable which the optimizer outputs is fed to a process model of the pilot control and, is added to at least one output variable of the control device to form the manipulated variable. A model output variable of the process model is fed to the control device as a set-point and fed back to the optimizer along with variables which cannot be measured in the technical process. A device for implementing the method is also described.

Abstract: A paste for screen printing of electrical structures on substrates, in particular ceramic substrates, which includes a mixture of inorganic solid particles having high sintering temperature and an inorganic binding agent having a low sintering temperature below the sintering temperature of the inorganic solid particles, wherein the inorganic solid particles having high sintering temperature are at least partially in the form of fibers. The strength and breaking reliability of the printed and then fired electrical structures, such as resistors and coating layers, may be increased by the fiber components in the printing paste.