Machine wire and small dia. bar surface fault detector - has longitudinally moving bobbin to analyse impedance at various frequencies

摘要

Superficial faults in long producers of circular cross section such as wire or small bars are detected by analysis of the complex impedance at several input current frequencies. A wire passes through an active probe comprising an inductive coil (11) wound on a hollow support (12) of a guide tube (13) through which the wire passes at high temp. The coil assembly forms part of a Wheatstone bridge circuit and is housed in a non-magnetic sealed enclosure such that guide is in the direction of travel. The coil is cooled by water which flows via inlet (20) and outlet tubes (21).