Automated sonic velocity calculation based on ultrasonic resonator measurements for on-line process monitoring

• Precise on-line capable sonic velocity determination from ultrasonic resonators.
• Improved accuracy to a deviation 0.011 m s−1 and a theoretical sonic velocity determination of 0.027 m s−1.
• Very high precision of less than 0.3 mm s−1.
• A setup and an evaluation method are introduced ensuring a maximum in precision and accuracy for on-line process monitoring.

Many applications of sonic velocity measurements for material testing are known and widely employed. Yet the technique is rarely employed in biotechnology especially for process monitoring. The ultrasonic resonator technology allows a highly precise measurement of the sonic velocity in small volumes, which makes this technology interesting for process analytics. New techniques give information about various process parameters on-line and in real time. Nowadays special interest is the on-line product analytic. Not only is the product concentration is in focus, but the purity and activity, which are currently rarely accessible on-line. The ultrasonic resonator is an opportunity to close this gap. An evaluation method will be introduced to ensure a maximum in precision and accuracy during the measurement. The best obtained precision of less than 0.3 mm s−1 sonic velocity and an accuracy of 0.027 m s−1, for water at different temperatures, give the possibility to detect slightest changes and recover worthwhile information during the measurements.