Axial and circumferential flaw sensing eddy current probe

摘要

A rotating field eddy current probe for sensing flaws in electrically conductive tubing is disclosed. The probe includes two stimulation coils physically arranged at 90 degrees to each other about an axis a current sensing portion. The a first alternating current is applied to one of the stimulation coils at a first phase and a second alternating current is applied to the second of the stimulation coils at a second phase, said second phase being electrically 90 degrees apart from said first phase and creating a rotating oscillating magnetic field.

主权项

1. A rotating field eddy current probe for sensing flaws in electrically conductive tubing having a circular cross section comprising:
two stimulation coils wound about a first common bobbin and physically arranged at 90 degrees to each other about an axis through the center of said stimulation coils and said first common bobbin, said bobbin being arranged such that said axis is aligned longitudinally with the tubing and a current sensing portion; wherein a first alternating current is applied to the first of said stimulation coils at a first phase and a second alternating current is applied to the second of said stimulation coils at a second phase, said second phase being electrically 90 degrees apart from said first phase, said first and second alternating currents configured to induce eddy currents in said tubing wherein said current sensing portion comprises at least a first pair of detection coils wound about a second common bobbin and physically arranged at 90 degrees to each other about said axis and configured to sense a rotating field produced by said eddy currents induced in the tubing.