| 摘要 |
A plurality of eddy-current generators are angularly grouped about an axis within an inspection tool or probe. Each eddy-current generator presents a circumferentially extending test segment. Collectively, the test segments form a discontinuous test gap which extends circumferentially about the probe. In some embodiments, adapted for inspecting from the inside of tubing or fastener holes, the test gap is at the outer periphery of a probe. In other embodiments, adapted for inspecting from the outer surface portions of tubing, rods, etc., the test gap region extends around the inside of a central passageway formed through a support body. The eddy-current generators are supported for limited radial movement, enabling the tool or probe to adapt to differences in shape and dimension of the material being inspected. Each eddy-current generator combines low and high reluctance materials to (a) greatly reduce the mutual coupling of the several generators, (b) concentrate the reluctance of the eddy-current generators in the material to be tested, and (c) control the spatial extent and shape of generated eddy-currents.
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