Ultrasonic Particle Sizing

Abstract

The measurement of particle size distributions and particle concentrations is an important task in laboratories and in technical processes that deal with suspensions. Especially the instruments designed for on-line applications in production processes mostly evaluate the interactions of light with the suspended particles, viz. extinction, scattenng and diffraction. While the interaction of particles with ultrasonics is essentially the same as with light, the application of ultrasonics offers special technical advantages, which are due to the extremely broad range of wavelengths and the coherent detection of ultrasom·c waves. Ultrasonic spectrometry makes possible the on-hne measurement of the particle size distribution and particle concentration in suspensions at concentrations of up to 30% by volume without diluting the suspension. This paper is intended to introduce the reader to the fundamentals of ultrasonic particle sizing and to explain present efforts in this field. In the last section, some successful realizations of ultrasonic particle sizing instruments are presented.

Experimental Characterization Techniques for Solid-Liquid Slurry Flows in Pipelines: A Review

“…The following summary provides an overview of main commercial online and offline techniques [16,20,21]:…”

“…Then, the ultrasound extinction pattern of the sample is then converted to a particle size distribution (PSD), similarly to laser diffraction, and a particle concentration is attained by mathematical deconvolution through a matrix (either calculated from a theoretical model or obtained in an empirical way from measurements with known size fractions of the same material) that contains attenuation patterns per unit volume of particles in defined size classes. Moreover, to construct the model-based matrix, various properties of both particulate phase and dispersion medium must be known, related to thermodynamic, mechanical, and transport behavior [20,27,28].…”

“…Attenuation of sound waves from clusters of particles in the medium, which is more prominent at high particulate concentration. Interactions between ultrasound and a particle (adapted from [20,27]).…”

“…Transition from the first measurements in a laboratorial setting, circa 1972, to commercial availability occurred in just 7 years and through the 1970s, DLS gained wide acceptance among experts in light scattering [29]. Interactions between ultrasound and a particle (adapted from [20,27]).…”

“…For Brownian motion the autocorrelation function is an exponential whose decay constant is a measure for the particle diffusion coefficient which is generally used for particle size determination [30]. Interactions between ultrasound and a particle (adapted from [20,27]).…”