Patent ID: 8421449
Filing Date: 2013-04-16
Classification: G01N

Abstract:
1. An eddy-current flaw detection method for performing eddy-current flaw detection of a conductive pipe by using a magnetic element group of which a specified number of magnetic elements, which excite or detect a magnetic field, are evenly spaced in each of at least two rows that are formed around the surface of a column shaped casing that is formed such that it can be inserted into the conductive pipe, with one of the two rows being located at a position that differs from the other row by ½ the even spacing in the row direction, and switching circuits for switching the magnetic elements in the respective row of the magnetic element group at time-division, comprising: a step of causing the switching circuit to switch the magnetic elements in one row at time-division in order to excite a magnetic field; and a step of causing the switching circuit to switch, at time-division, two magnetic elements that are arranged in the other row and that are located at positions that differ from the magnetic element that excited the magnetic field by 3/2 the even spacing in the row direction in order to detect the excited magnetic field.