High temperature liquid level monitoring using Capacitive Micromachined Ultrasound Transducer (CMUT)

Measuring various parameters such as flow rate in pipelines, defect in pipelines or containers walls, or liquid level in containers at high temperature is crucial, yet has widespread applications in industries including chemical, pharmaceutical, and food and beverage industries. For example, different operation and installation conditions of the processes that require liquid level measuring in high temperature is critical for the choice of sensor technology. In the field of ultrasonic level sensing, conventional piezoelectric transducers are limited in measurements at temperatures below their curie temperature. One of the unique advantages of silicon based CMUTs over piezoelectric transducers is very high temperature stability. In this work, we successfully demonstrated the performance of CMUT for liquid level detection at temperatures beyond 200°C, with no degradation in signal.