AUTOMATIC ULTRASONIC FLAW DETECTOR

PURPOSE:To obtain the functions of AUST and to realize long-period use, by providing a hollow ring detection part united with a rotating mechanism part to the front of an automatic ultrasonic flaw detector which detects a flaw of a material to be tested by moving the material to be tested straight on the holle shaft of the rotating mechanism part. CONSTITUTION:The hollow ring detecting part 15 is provided in front of a fixation frame 3 for the rotating mechanism part and four contactless sensors 16a- 16d are arranged at intervals of 90 deg. on the same tip circumference of the hollow ring detecting part. Those sensors are arranged in four up, down, left, and right quadrants on the same circumference of the hollow ring detecting part and when the material to be tested passes by, they generate voltages corresponding to the distances from the sensors. The output voltages of the two up and down contactless sensors 16a and 16c are amplified by amplifiers 17a and 17c and converted by analog-digital converters 18a and 18b into digital signals respectively. Those two digital signals are compared with each other by a comparing and computing element 19 to find the difference in digital value and its direction, and an ascending or descending command is sent out to a motor controller 21. The motor controller 21 controls the rotating direction of a motor 7 according to the ascending or descending command.