APPARATUS FOR DETECTING THE PRESENCE OF ELECTRICALLY-CONDUCTIVE DEBRIS

摘要

Apparatus for detecting the presence of electrically-conductive debris in a flow passageway has a bridge circuit with four arms. One arm of the bridge has a coil (10) arranged to monitor the flow passageway. Operating circuitry provides alternating current across one diagonal of the bridge, monitoring circuitry monitors imbalance in the bridge across the other diagonal of the bridge, and balancing circuitry responds to an output of the monitoring circuitry for adjusting the value of at least one component of the bridge circuit in such a way to reduce imbalance in the bridge.