Development and manufacturing of non-
destructive testing units and system
Ultrasonic Flaw Detector NOVOTEST UD2301
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9 . Calibration of the flaw detector
9.1.
Measuring of prism delay for direct transducer
During operation with the direct transducer abrasion occurs with
prism, it cause to changes of delay of the signal in transducer. Given
that the propagation of time in the prism transducer significantly
affect the accuracy of calculation of the coordinates of the reflectors
it is very important to accurately measure the delay in the prism and
periodically update this parameter.
Measurement of prism delay of direct transducer made using a
standard sample SO-2.
To measure delays in the prism of transducer it is necessary to get a
first reflected signal (the first ground signal) on a standard sample
SO-2 on the side of 59 mm and put this signal into one of the control
gates, for example gate A.
Configure the display of the measured parameters - display the
value of the propagation time along the beam or propagation time
required for the control gate, in this example - La and Ta
accordingly.
Time of propagation of ultrasonic vibrations in the prism of direct
transducer in microseconds equals:
2t = t1
– 20 µs,
where t1 - the time between excitation pulse and the echo from the
surface of the standard sample SO-2 at the side 59 mm with
transducer position corresponding to the maximum amplitude of the
echo signal, for this example - the value La or Ta;
20 µs - the propagation time of the ultrasonic vibration in the
standard sample on the side of 59 mm.
