METHOD AND DEVICE FOR MEASURING TEMPERATURE OF METALLIC WORKING MATERIAL AND SOLID SOLID MATERIAL PORTION

摘要

PCT No. PCT/DE94/01311 Sec. 371 Date May 9, 1996 Sec. 102(e) Date May 9, 1996 PCT Filed Nov. 7, 1994 PCT Pub. No. WO95/13532 PCT Pub. Date May 18, 1995The invention relates to a measuring process for the indirect measurement of the temperature and solids content of metal workpieces during inductive heating. To this end, in a coupled coil system comprising a heating coil, the effect of alterations in the electrical conductivity of the workpiece is determined by the combination, using circuit-mathematical techniques, of a signal tapped from the exploring coil with a reference signal from the driving coil. The two signals are combined in such a way that the measurement signal obtained depends solely on the phase shift between the reference signal and the exploring coil signal and/or on the quotient of the amplitude values of the reference signal and the exploring coil signal. This facilitates measurement which is independent of the amplitude of the alternating electromagnetic field created by the driving coil. With the aid of alloy- and geometry-specific calibration curves, the measurement signal can be associated with the particular value being sought (temperature or solids content). In addition, the measurement signal can be used for the continual adjustment of the heating in order to regulate the target value.