| 摘要 |
PURPOSE:To detect abnormality of thickness size and a two-sheet cracking defect distinctively by inputting detection signals obtained from time base differences between a surface echo, and a bottom surface echo and a defect echo to two comparators, and comparing them with respective set values. CONSTITUTION:The reflection echo of an ultrasonic wave received by a probe 4 is inputted to a decision device 20 through an amplifying and detecting circuit 7, a comparator 8, a gate generating circuit 10, a time-voltage converting circuit 11, and an A/D converter 12 and also supplied to a thickness display device 14 through a holding circuit 13. Then, the decision device 20 has the warning area circuit 23 consisting of a warning value comparator 21 and a continuity counter 23, the abnormal area circuit 23 consisting of an abnormal value comparator 24 and a repetitiveness counter 25, and a decision circuit 27 and outputs an abnormal thickness size signal 28 and a two-sheet cracking defect signal 29. |
