| 摘要 |
PURPOSE:To detect the seam of a steel pipe or the like with high accuracy, by providing a first -shaped core generating magnetic flux at a right angle to the welded part of a material to be examined and a second -shaped core generating magnetic flux in the longitudinal direction of the welded portion. CONSTITUTION:One 30 of the -shaped megnet cores is put in parallel with the longitudinal direction of a steel pipe 20, while the other -shaped magnet core 40 is arranged in the diametral direction of the steel pipe 20; both of the -shaped cores are arranged in an L-shaped form. The primary winding P is made on two of the cores attached to each other, while the second winding SR is made on the leg 31 of the core 30 and the second winding SC is made on the leg 41 of the core 40. Hence the primary winding P is driven by AC and voltage is induced to each of the secondary windings SC, SR. When these cores are installed on a seamless steel pipe in such a way that the difference between SC and SR is reduced to zero, a detection signal can be obtained when they are installed on the seam part. By amplifying the signal, the seam part can be detected effectively. |
