EDDY CURRENT CONVERTER FOR FLAW DETECTION Russian patent published in 2023 - IPC G01N27/90 

FIELD: non-destructive testing.

SUBSTANCE: invention can be used for flaw detection of electrically conductive objects. The eddy current converter (ECC) contains rectangular measuring inductance coils 1, 2, 3 and rectangular excitation coil 4 located in the plane of working end 5 of the converter. Measuring coil 1 and excitation coil 4 are arranged in a T-shape. Coil 1 passes through axis 5 of coil 4, orthogonal to opposite sides 4.1, 4.2 of coil 4 and to working end 6 of the converter. Measuring coils 2 and 3 are made identical and are located symmetrically on opposite sides of measuring coil 1 in planes parallel to it. Measuring coil 1 is connected in series opposite to the magnetic flux directed along their common axis 7, with measuring coils 2 and 3, while the outer leads of coils 2 and 3 form the output of the ECС. The number of turns W₁, W₂, W₃ in measuring coils 1, 2, and 3, respectively, are selected based on the ratios W₁ = W₂ + W₃ and W₂ = W₃. Six extrema of the axial component H_x of the magnetic field appear above the surface of the defective zone. When changing the angle γ the number of extrema interacting with measuring coils 1-3 increases, which ensures a weak dependence of the maximum stress introduced under the influence of a crack on γ.

EFFECT: increasing the reliability of control due to a significantly smaller change in the maximum amplitude of the recorded eddy current signal when changing the angle γ between the normal to the crack plane and the scanning direction, as well as due to a higher degree of suppression of the effect of distortions of the plane of the working end of the eddy current converter relative to the surface of the controlled object.

1 cl, 17 dwg