Gas density sensor for real-time monitoring in a high pressure reactor

We present the design of a gas density sensor based on quartz crystal resonators for high pressure (2.5 × 106 Pa) and high temperature (340 K) application. Tunning fork resonators have successfully been used in gas density measurements. In our contribution tuning fork and thickness-shear mode devices are compared with respect to their sensitivity to gas density. It was confirmed, that tuning fork resonators are mainly sensitive to density, whereas shear-mode resonators aremore suitable for viscosity measurement. In high pressure gases, an additional pressure dependent frequently shift has to be considered.