Method and means for detecting metal bodies on a moving web

摘要

The metal object detection method uses an AC electromagnetic field directed onto the continuous material web (20), with detection of phase and/or amplitude variations caused by a metal object (22), by comparing the received signal with at least one compensation signal, e.g. obtained by superimposing a pair of phase offset compensation signals, each having a constant phase relative to the AC electromagnetic field and a variable amplitude. An independent claim for a metal object detection device is also included.