Chapter 4 Transducer installation
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4.1.5. N method
With the N method, the sound waves traverse the fluid three times and bounce
twice off the pipe walls. It is suitable for small pipe diameter measurement.
The measurement accuracy can be improved by extending the transit distance
with the N method (uncommonly used).
4.2.
Transducer mounting inspection
Check to see if the transducer is installed properly and if there is an accurate and
strong enough ultrasonic signal to ensure proper operation and high reliability of
the transducer. It can be confirmed by checking the detected signal strength, total
transit time, delta time as well as transit time ratio.
The "mounting" condition directly influences the flow value accuracy and system
long-time running reliability. In most instances, only apply a wide band of sonic
coupling compound lengthwise on the face of the transducer and stick it to the
outside pipe wall to get good measurement results. However, the following
inspections still need to be carried out in order to ensure the high reliability of the
measurement and long-term operation of the instrument.
