Patent ID: 8104349

Claim:
A flaw detecting tracking device for a pipe or tube, by which a flaw detecting sensor disposed opposite to an outer surface of a pipe or tube and relatively moving along an axial direction of the pipe or tube, for detecting a flaw on the pipe or tube rotated in a circumferential direction, tracks the pipe or tube, the tracking device comprising: at least one non-contact type displacement gauge for measuring displacement at the outer surface of the pipe or tube in a non-contact state; a positioner for moving the flaw detecting sensor within a plane perpendicular to an axial direction of the pipe or tube along the opposite direction of the pipe or tube to the flaw detecting sensor and a direction perpendicular to the opposite direction; and a positioning controller for controlling the positioner, the positioning controller predicting a time until a portion of the pipe or tube whose displacement is measured by the non-contact type displacement gauge reaches a predetermined position on a straight line extending in the opposite direction through the rotational center of the pipe or tube on the basis of the positional relationship between the non-contact type displacement gauge and the flaw detecting sensor and a rotational speed of the pipe or tube; controlling the positioner on the basis of the displacement measured by the non-contact type displacement gauge and an operational delay time of the positioner in such a manner that the relative position of the flaw detecting sensor after the lapse of the predicted time to the pipe or tube after the lapse of the predicted time becomes substantially constant in the opposite direction; and moving the flaw detecting sensor along the opposite direction, and the positioning controller predicting a time until a portion of the pipe or tube whose displacement is measured by the non-contact type displacement gauge reaches a predetermined position on a straight line extending in the perpendicular direction through the rotational center of the pipe or tube on the basis of the positional relationship between the non-contact type displacement gauge and the flaw detecting sensor and a rotational speed of the pipe or tube; controlling the positioner on the basis of the displacement measured by the non-contact type displacement gauge and an operational delay time of the positioner in such a manner that the relative position of the flaw detecting sensor after the lapse of the predicted time to the pipe or tube after the lapse of the predicted time becomes substantially constant in the perpendicular direction; and moving the flaw detecting sensor along the perpendicular direction.