Abstract: The invention relates to a levitation melting process and a device for producing castings with movable induction units. In this process, induction units are used in which the opposite ferrite poles with the induction coils are movable and move in opposite directions. In this way, the induction units for melting the batches can be arranged close together in order to increase the efficiency of the induced magnetic field. When casting the molten batch, the induced magnetic field is reduced by increasing the distance between the ferrite poles with the induction coils, thus preventing the melt from touching the ferrite poles or the induction coils.

Abstract: The invention relates to a levitation melting process and a device for producing castings with movable induction units. In this process, induction units are used in which the opposite ferrite poles with the induction coils are movable and move in opposite directions. In this way, the induction units for melting the batches can be arranged close together in order to increase the efficiency of the induced magnetic field. When casting the molten batch, the induced magnetic field is reduced by increasing the distance between the ferrite poles with the induction coils, thus preventing the melt from touching the ferrite poles or the induction coils.

Abstract: A method for producing cast items in a casting method, wherein a charge of a conductive material is introduced into the sphere of influence of at least one alternating electromagnetic field, so that the charge is kept in a levitating state. The melt is poured into moulds in order to produce turbine blades, prostheses or turbocharger impellers.

Abstract: A method for producing cast items in a casting method, wherein a charge of a conductive material is introduced into the sphere of influence of at least one alternating electromagnetic field, so that the charge is kept in a levitating state. The melt is poured into moulds in order to produce turbine blades, prostheses or turbocharger impellers.

Abstract: A pressure relief valve for the working pressure of a servo-steering mechanism of a vehicle, with a pressure medium connection between a high pressure connection adapted to be placed under a working pressure and a zero connection adapted to be placed under a lower pressure, whose valve-adjusting member is retained in a normal rest position closing off the pressure medium connection during normal conditions by a control device operating as a function of an operating magnitude of the servo-steering mechanism and which upon exceeding a critical value of the operating magnitude is adapted to be displaced into a by-pass position more or less opening up the pressure medium connection; the control device thereby operates in dependence on the load of the servo-steering mechanism while the by-pass position is independent of the angle of rotation of the steering shaft of the servo-steering mechanism.