| 摘要 |
PURPOSE:To elevate the detection accuracy with an accurate following of a flaw detector to the inner wall surface of a steel pipe by connecting the flaw detector with a running guide roller contacting the surface to be inspected to a move-in and out frame through a universal joint. CONSTITUTION:When a steel pipe pile 34 being cut is pressed against an adjacent steel pipe pile 36 through a joint 35 or deformed, for example, as shown by the numeral 37, by an abnormal external force, a clearance (d) is generated between the surface 6 to be inspected and a guide roller 7. This varies the space between the surface 6 being inspected and an electromagnetic sensor 2 causing errors in the measured to a proper value (f) to (e). To eliminate this, a universal joint 14 is provided between a protective frame 5 with a detector and a move-in and out frame 24. The detector is driven freely corresponding to the deformation of the surface 6 being inspected to hold the space between the electromagnetic sensor 2 and the surface 6 being inspected at the optimal distance (f) for measurement thereby enabling a greater detection accuracy. |
