Fluid density, surface tension and viscosity measurement - using ultrasonic suspension of drop at pressure node and adjusting transmitter compensation voltage

摘要

Device determines density, surface tension and viscosity of small fluid volumes without requiring sensor contact with the vol. wall. Measurements are carried out on single fluid drops. The fluid sample is placed in a standing ultrasonic wave and held suspended as a drop at a pressure node. The ultrasonic transmitter compensation voltage is adjusted to position the drop at the same height as a reference fluid drop and gives a measure of the density. Surface tension and viscosity are determined from the resonance curve of volume oscillations induced by l.f. amplitude modulation.