A precision densimeter which compensates for liquid viscosity

This paper describes a new densimeter, consisting of a compact pencil-sized density detector probe and a microprocessor-based display unit. The densimeter measures densities in the range 650–1500 kg/m
³
to an accuracy of ±0.5 kg/m
³
, and automatically compensates for liquid viscosities up to 1 N · s/m
²
. The densimeter measures liquid density by the natural frequency of a thin-walled cylinder at the tip of the probe. The natural frequency varies with the density of the liquid the probe tip is immersed in. Viscosity of the liquid also affects the natural frequency of the cylinder immersed in it, as well as the amplitude of oscillation. The detector measures both the frequency and the Q factor at resonance, and uses this information to compensate for the effects of liquid viscosity.