ULTRASONIC DEVICE FOR INSPECTION OF FERROMAGNETIC ARTICLES Russian patent published in 1995 - IPC

FIELD: nondestructive testing. SUBSTANCE: electromagnetoacoustic converter of ultrasonic device for inspection of ferromagnetic articles is manufactured in the form of bar magnet embraced over side surface with magnetic flux concentrator in the form of ferromagnetic cylinder dissected along generating line into four equal parts located close to working butt of magnet. It includes four excitation coils lying in one plane, having shapes of sectors, ring measuring coil enveloping them. Device is also provided with three additional circuits composed of pickup of correction of resonance amplifier linked to correction unit, with four regulators of amplitudes value of excitation current which inputs are tied together with excitation generator, controlling inputs are connected to proper outputs of correction unit and which outputs are coupled to corresponding excitation coils. Device has amplifier with controlled amplification factor to which signal measuring coil is connected, to which controlling input fifth output of correction unit is linked and which output is coupled to input of measuring unit. Correction pickups present Hall converters anchored on proper parts of magnetic flux concentrator which current circuits are linked to output of A. C generator. EFFECT: enhanced authenticity of inspection due to reduced influence of change of gap between electromagnetoacoustic converter and tested article. 2 dwg