Patent ID: 7737683
Filing Date: 2010-06-15
Classification: G01V

Abstract:
1. A process for detecting and distinguishing, respectively, parts in a material flow which influence an electromagnetic alternating field, comprising the generation of an electromagnetic alternating field extending across the width of the material flow, the generation of a relative motion between the electromagnetic field and the material flow, and the detection of a phase signal portion (PS) and an amplitude signal portion (AS) of a detection signal (DS) by means of a detector coil ( 4 ) comprising two windings ( 4 a , 4 b ) connected inversely, which detector coil is arranged in the effective range of the electromagnetic alternating field, with the detection signal (DS) being derived from a variation of magnetic flux caused by the relative motion between the electromagnetic alternating field and a part located in the material flow and influencing the electromagnetic alternating field, characterized in that a locus curve ( 15 , 20 , 30 ) is formed from the progression of the detection signal (DS) by plotting the progressions of the phase signal portion (PS) and the amplitude signal portion (AS) of the detection signal (DS) as pairs of variates at the respective points of time in a system of coordinates and that the locus curve ( 15 , 20 , 30 ) is evaluated with respect to material-specific characteristics and an identification signal (ES) is emitted upon detection of a material-specific characteristic.