Piezoresistive immersion viscometer

Abstract

Rheometry refers to experimental techniques to measure the rheological properties of material. Various rheometers and viscometers have been developed with distinctive characteristics in accuracy, cost, amount of liquid volume, apparatus’s dimension, probing ranges of liquid properties, and complexity of operating process. In this study, an immersion viscometer for the measurement of the steady shear viscosity and shear stress is reported. The piezoresistive immersion viscometer is easily built with low cost and worked in wide range of the liquid shear viscosity (0.1 to 1,000 Pa s) and stress (0.3 to 30 Pa) with a few milliliters of the volume of liquid. An immersed plate connected to a piezoresistive beam moves through liquid filled in a trough and causes the change in the resistance of the piezoresistive beam. Based on the dimensional analysis to correlate the resistance variation with other physical parameters in the system, the empirical equation for the rheometry is derived. The validity of this equation is demonstrated through the measurement of the shear viscosity and stress of honey and xanthan gum solution. This device will provide a compact rheometry with simple operating process and on-line measurements.