NEAR FIELDTM AND COMBINATION NEAR FIELDTM - REMOTE FIELD ELECTROMAGNETIC TESTING (ET) PROBES FOR INSPECTING FERROMAGNETIC PIPES AND TUBES SUCH AS THOSE USED IN HEAT EXCHANGERS

摘要

Ferromagnetic pipes and tubes are inspected for flaws by inserting probes having a near field sensor comprising at least one send coil (50) and at least one receive coil (52) which are located directly adjacent one another. According to various configurations, the send and receive coils (50,52) are of the same or different diameters or are positioned axially adjacent one another. Configurations of the near field sensor include arrangements wherein there are pluralities of send coils (50) as well as pluralities of receive coils (52). The near field sensor is in one embodiment in combination with remote field sensor coils and in another embodiment in combination with a remote field sensor and a remote field receive coil.