Magnetic device for determining defects in rod-like elements,cables,steel pipes and the like

Claim 1

A MAGNETIC DEVICE OF DETERMINING DEFECTS IN RODLIKE ELEMENTS, CABLES, STEEL PIPES, ETC., MOVING ALONG A PATH OF TRAVEL, SAID DEVICE COMPRISING, IN COMBINATION A PERMANENT MAGNETIC ASSEMBLY INCLUDING TWO SUBSTANTIALLY IDENTICAL PERMANENT MAGNET SECTIONS SPACED APART LONGITUDINALLY OF THE PATH OF TRAVEL OF THE TEST ARTICLE, EACH PERMANENT MAGNET ASSEMBLY BEING ELONGATED IN THE DIRECTION OF MOVEMENT OF THE TEST ARTICLE; EACH PERMANENT MAGNET SECTION LATERALLY SURROUNDING SAID PATH OF TRAVEL AT A RESPECTIVE LOCATION THEREALONG; EACH PERMANENT MAGNET SECTION INCLUDING A TUBULAR POLE PIECE SUBSTANTIALLY CENTERED ON SAID PATH OF TRAVEL AND DEFINING A RELATIVELY ELONGATED PASSAGE FOR THE ARTICLE, AND CONSISTING OF TWO PARTS BEING AT LEAST PARTIALLY SEPARABLE FOR POSITIONING AROUND THE ARTICLE; EACH PERMANENT MAGNET SECTION FURTHER INCLUDING ANISOTROPIC PERMANENT MANGETS EXTENDING RADIALLY OUTWARDLY FROM THE RESPECTIVED POLE PIECE, HAVING FIRST POLES OF THE SAME POLARITY IN ENGAGEMENT WITH THEIR RESPECTIVE POLE PIECE, AND HAVING SECOND POLES OF THE SAME OPPOSITE POLAIRTY; THE FIRST POLES OF THE PERMANENT MAGNETS OF ONE PERMANENT MAGNET SECTION HAVING A POLARITY OPPOSITE TO THAT OF THE FIRST POLES OF THE PERMANENT MAGNETS OF THE OTHER PERMANMENT MAGNET SECTION; PARAMAGNETIC MEANS INTERCONNECTING THE SECOND POLES OF ALL OF SAID PERMANENT MANGETS TO DEFINE A MAGNETIC FLUX PATH COMPLETE EXCEPT FOR THE AIR GAP ALONG SAID PATH OF TRAVEL BETWEEN THE LONGITUDINALLY SPACED FACING ENDS OF SAID TUBULAR POLE PLECES,