MEASURING DEVICE FOR LEVEL OF MOLTEN STEEL

摘要

PURPOSE:To measure exactly the level of a molten steel by an eddy current system by dividing a detecting coil which generates electromotive force corresponding to the level of the molten steel to two pieces, connecting differentially the divided coils and shielding one of the coils with a nonmagnetic electrical conductor. CONSTITUTION:A detecting coil 14 which generates electromotive force according to the various levels of a molten steel by the secondary magnetic field which the eddy current generated by an excitation coil 12 creates is divided to two pieces; the 1st detecting coil 14A and the 2nd detecting coil 14B which are differentially connected to each other. Only the coil 14B on the side where the coil does not face the molten steel is shielded with a nonmagnetic electrical conductor such as Al plate having about 5mm. thickness. The signal for the information on the level of the molten steel is mostly shielded by the plate 32. Said signal enters an amplifier 22 without being erased by the differential connection and is thus amplified and detected. The magnetic field for electromagnetic stirring is a low frequency and is not mostly shielded by the plate 32, the magnetic field is caught by both of the coils 14A and 14B and is mostly offset by the differential coupling.