Eddy current test apparatus for annular welds

摘要

Non destructive test apparatus for the inspection of annular welds, such as the tube/tube sheet welds of a tube-in-shell heat exchanger, using eddy current techniques. The apparatus comprises a rotatable probe assembly having a pair of sensors for interrogating the weld, bridge means for comparing the signals produced by the sensors and electronic circuitry arranged to combine the differential of the signals with a simple voltage locus signal derived from a sine/cosine potentiometer associated with the probe assembly drive and to feed the combination signal to an oscilloscope.