A2.4 - Accurate Determination of Viscosity and Mass Density of Fluids using a Piezoelectric Tuning Fork Resonant Sensor
- AMA Conferences 2015
2015-05-19 - 2015-05-21
- Proceedings SENSOR 2015
- A2 - Mechanical Sensors
- A. Niedermayer, T. Voglhuber-Brunnmaier, M. Heinisch, B. Jakoby - Institute for Microelectronics and Microsensors, J. Kepler University, Linz (Austria)
- 66 - 71
Resonant sensors yield outstanding performance in the measurement of viscosity and mass density of fluids when signal conditioning, signal processing and thermal control are optimized and the fluid-mechanical model of the electromechanical resonator is suitable and accurate for the particular resonator. The combination of several advancements achieved in the last years significantly increases the performance achievable with this type of sensors. In this contribution the performance of a novel and highly universal evaluation system is demonstrated using a commercially available quartz crystal tuning fork resonator as sensing element for liquid viscosity and mass density. The obtained results are quantified with respect to an accurate lab bench viscosity and mass density meter. A significant advantage of this system is that it operates reliably and accurately even for very low quality factors (Q < 10). Therefore, the sensor elements can be used in a larger viscosity range than with alternative evaluation methods. Furthermore, the error propagation of the system can be estimated for each operating point, allowing the adaption of the measurement conditions (e.g. measurement time) to achieve a predefined accuracy. The implemented fully digital signal processing chain furthermore provides outstanding reproducibility of results, noise immunity and flexibility.