Abstract: The method according to the invention comprises producing an alternating magnetic flux coupled to an electrically closed loop which includes a pipeline to be checked, and measuring at least on electromagnetic field parameter over the whole length and perimeter of the pipeline. The distribution function of the electromagnetic field parameter thus obtained is indicative of the state of the pipeline. The method is more effective than the conventional techniques in that it ensures a more uniform spreading of current over the pipeline, in that it makes possible to inspect hard-to-get-at portions of pipelines without installing magnetic flux excitation means at those portions, and in that it rules out the effects of the magnetic flux on the output signals of measuring transducers. The invention is further concerned with a device for nondestructive inspection of pipelines primarily, pipelines, of atomic power stations.

Abstract: An automatic eddy current inspection system for discrimination of defects in elongated parts made of conducting materials comprises an alternating current generator connected in series to an amplitude selector via a differential encircling eddy-current transducer and a detector. The amplitude selector has two selection levels. The system also comprises a signal analyzer with a controllable switch and the following counters: a counter for determining the length of long cracks; a minor defects counter; a major defects counter; and a counter for determining the length of tested parts. The outputs of the counters are connected to the inputs of a sorter having its outputs connected to quality grade indicators. The controllable switch of the signal analyzer has its control input connected to the output of the amplitude selector which corresponds to a higher selection level.

Abstract: The proposed eddy current converter for non-destructive testing of electrically conductive coating in holes of printed circuit boards comprises a cylindrical frame enveloped by an exciting winding and a measuring winding and inserted into a hole of a printed circuit board being tested. The coils of the exciting and measuring windings extend along the generatrices of the cylindrical frame.With the use of the proposed converter, the testing accuracy is independent of the parameters of respective contact areas of a hole being tested. The converter of the present invention is sensitive to the most undesired flaws like transversely extending cracks.