| 摘要 |
850,478. Ultrasonic inspection devices. REALISATIONS ULTRASONIQUES. Aug. 7, 1957 [Aug. 11, 1956], No. 24888/57. Class 40(7). Apparatus for the continuous inspection of a plane test object moving along a predetermined path comprises a liquid-filled container transparent to ultrasonic waves and enclosing ultrasonic transmitting means producing a pencilshaped beam passing through the liquid to enter the test object normally, means generating beam scanning transversely to the predetermined path and cathode-ray tube (C.R.T.) display means incorporating a long-persistence screen, horizontal electron beam scanning in synchronism with the ultrasonic beam scanning, vertical electron beam scanning and a control grid connected to the ultrasonic receiver. Echo or absorption flaw detection may be used and the transmission may be unmodulated,. pulsed or continuously frequency-modulated. In the pulse-echo embodiment a slot 2 in travelling belt 3 enclosed in oilfilled cylinder 4 having flexible walls transparent to ultrasonic waves provides a pencil beam tranversely scanning longitudinally-moving test sheet 6, transducer 1 being used for transmission and reception. The test sheet cross-section is displayed by intensity-modulation of a C.R.T. scanned horizontally in synchronism with the belt motion and vertically by a sawtooth sweep synchronized with the pulse transmission; C.R.T. screen 7 thus displays luminous lines 9, 10 representing top and bottom test sheet boundaries and a flow is indicated by a luminous spot 11. In an absorption detector a scanning pencil beam is produced by a rotating reflector at the focus of a stationary parabolic reflector which faces a stationary and inclined plane reflector, a similar arrangement for reception being mounted below the test sheet, Figs. 5 and 6 (neither shown); unmodulated or continuous frequency-modulated waves may be used, Figs. 7 and 8 (neither shown). |
