Ultrasonic flaw detector

An ultrasonic flaw detector for detecting any flaw existing in the inner peripheral corner section of a joint portion between a cylindrical vessel and a cylindrical member projecting from the barrel of said cylindrical vessel by means of an ultrasonic wave applied from the outer peripheral corner of said joint portion, said outer peripheral corner section having a rounded surface, comprising:

• a cylindrical track adapted to be secured around the outer periphery of said cylindrical member;
• a driving mechanism mounted on said track and moveable along said track, said driving mechanism including a circumferential driving source and an axial driving source;
• a rod slidably movable in the axial direction by said axial driving source of said driving mechanism;
• a frame connected to said rod in such a manner as to be able to move in the radial direction of said cylindrical member;
• a probe pivotally supported by said frame;
• and
• control means for controlling the movement of said probe such that the pivot axis of said probe follows the locus of the center of curvature of the rounded surface of said outer peripheral corner section of said joint portion.

An ultrasonic flaw detector for detecting any flaw existing in the inner peripheral corner section of a joint portion between a cylindrical vessel and a cylindrical member projecting from the barrel of said cylindrical vessel by means of an ultrasonic wave applied from the outer peripheral corner section of said joint portion, said outer peripheral corner section having a rounded surface, comprising:

• a cylindrical track secured to the outer periphery of said cylindrical member;
• a driving mechanism mounted on said track for movement along said track, said driving mechanism having a circumferential driving source and an axial driving source;
• a rod slidably movable in the axial direction by said axial driving source of said driving mechanism;
• a frame connected to said rod so as to be able to move in the radial direction of said cylindrical member;
• a probe pivotally supported by said frame;
• a position detecting means mounted on said frame and adapted to detect the axial position of said probe;
• and
• control means adapted for controlling said driving mechanism in accordance with a signal from said position detecting means such that the pivot axis of said probe follows the locus of the center of curvature of the rounded surface of said outer peripheral corner section of said joint portion.