Institut Dr. Foerster Gmbh & Co. Kg

Institut Dr. Friedrich Forster Pruferatebau

Franz Haditsch

Stefan Koch

Matthias Boecker

Gunter Stritzke

Herman Besendorfer

Matthias BÖCKER

A feed-through coil arrangement for an apparatus that tests long products via eddy current includes an exciter coil arrangement with an exciter coil having a passage opening for the long product, and a receiver coil arrangement around the opening. The receiver coil arrangement includes two segment coil arrangements distributed over the passage circumference, wherein each segment coil arrangement has a detection range covering only a circumferential section of the long product circumference. The segment coil arrangements are distributed over two shells surrounding the opening at different distances to a reference axis. First segment coil arrangements on a first shell are without reciprocal overlapping and second segment coil arrangements on a second shell are without reciprocal overlapping. The first and second segment coil arrangements are arranged circumferentially offset to one another such that the second segment coil arrangements detect circumferential sections not covered by the first segment coil arrangements.

Through-coil arrangement, test apparatus with through-coil arrangement and testing method

An eddy-current defect test instrument with a rotary head (30) and test probes (32, 34, 36, 38) offset-mounted along a circular track (66) with only one distance probe (40) to achieve compensation for variations in spacing between the probes and the workpiece which only requires one distance signal processing device (60) and only one rotary transmitter (100). This is accomplished by storing the control signals obtained from the distance probe during one revolution of the rotary head (30) and retrieving those control signals associated with the probe position and appropriately modifying a defect signal.

Eddy-current defect test instrument with multiple test probes and one

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Reutlingen, Germany

Franz Haditsch