EDDY-CURRENT BUSHING CONVERTER FOR DETECTION OF FLAWS IN LONGITUDINALLY EXTENDED ARTICLES Russian patent published in 2000 - IPC

FIELD: nondestructive testing of articles of type of pipes and rolled products. SUBSTANCE: converter has one excitation winding, four differential pairs of measurement windings to detect flaws and four differential pairs of upper and lower windings to measure clearance. Converter also includes internal cylindrical metal screen with four sector cuts-out. Cuts-out have opening angle of 110-130 deg and are located along axis of converter. Centers of cuts- out are displaced along angle coordinate to points with ϕ₁= 0^°,, ϕ₂= 90^°,, ϕ₃= 180^°,, ϕ₄= 270^° and match centers of four zones of location of measurement windings along axis of converter. Each cut-out has width l_э= 3l₁+6l₂, where l₁ is width of measurement winding, l₂ is distance between measurement windings in each of four zones. Converter allows entire perimeter of pipe to be encompassed with the aid of four parallel measurement channels. In this case test zone of each channel decreases by factor four and signal-to-noise ratio increases approximately by same factor. EFFECT: encompassing of entire perimeter of pipe. 3 dwg