| 摘要 |
1,075,461. Ultrasonic flaw detection. ACCLES & POLLOCK Ltd. Nov. 27, 1964 [Feb. 21, 1964], No. 7269/64. Heading H4D. In a flaw-detection system for tubes, ultrasonic energy is directed into the wall of a tube from at least one transmitter and two receivers are so arranged as to receive energy reflected from both longitudinally oriented and transversely oriented flaws. In the embodiment of Fig. 6 two transmitters 15, 22 and two receivers 18, 21 are mounted on a carriage and positioned such that energy from the transmitters 15, 22 is reflected by a longitudinally oriented flaw 19 into receivers 21, 18 respectively and by a transversely oriented flaw 17 into receivers 18, 21 respectively. The magnitude of the signals received in the receivers 18, 21 enables the position of the flaw and its orientation to be determined. For continuous testing of lengths of tube the tube is rotated about its longitudinal axis in a tank of coupling-liquid, and either the carriage is moved along the tube or the carriage is fixed and the tube is moved longitudinally. Instead of rotating the tube, the carriage may be rotated. The transmitters 15,22 and receivers 18, 21 are adjustably mounted on the carriage and are tilted and spaced to give the desired results. An acoustic shield, attached to the carriage and resting on the tube, prevents direct transfer of energy from the transmitters 15, 22 to the receivers 18, 21 and locates them relative to the tube. A detailed calculation is given for positioning and angling the transmitters 15, 22 and receivers 18, 21 to detect flaws assumed to lie halfway through the wall of the tube. In a second embodiment (Figs. 1, 2, 3, not shown) only one transmitter (15) is used.
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