Patent ID: 9091717
Filing Date: 2015-07-28
Classification: G01N,G01R

Abstract:
1. A device for detecting electrically conductive particles in a liquid flowing in a pipe segment with a velocity (v), comprising a transmitter coil arrangement with at least one transmitter coil for exposing the liquid to a plurality of periodic alternating electromagnetic fields inducing a plurality of eddy currents in the particles; a receiver coil arrangement with at least one receiver coil for detecting a periodic electrical signal, according to the induced eddy currents and which has a carrier oscillation where at least one of an amplitude and a phase is modulated by the particles when the particles travel into an effective width of the receiver coil arrangement; a signal processing unit for producing a useful signal from a receiver coil signal; an evaluation unit for evaluating the useful signal to detect the passage of electrically conductive particles in a pipe segment; and a self-test unit which automatically or upon external request undertakes systematic quantitative checking of at least one of a plurality of signal processing functions of the signal processing unit, the transmitter coil arrangement, and the receiver coil arrangement, and upon external request to undertake calibration of the signal processing unit by means of a calibration standard replaces at least one of the transmitter coil arrangement and the receiver coil arrangement.