Compact viscosity sensors based on monolithic piezo actuators

The viscosity and density of fluids are important parameters for many applications in the medicine and biotechnology. In the known systems, the bulky standard viscosimeters do not allow a direct on-line measurement, but rather bypass systems or additional laboratory measurements are necessary. To avoid the disadvantages of the known solutions we designed a novel sensor element using monocrystalline Lithiumniobate actuators as monolithic bimorph acoustic resonators. Such sensor elements have nearly no inner friction and can be practically used nearly up to their Curie temperature of Tc=1100 degrees C. We have realized different immersion depths of up to 100% of the whole element length. The monocrystalline sensor element is chemically very stable being resistive against several chemical elements and compounds thus allowing to be used in many different environments and applications.