ULTRASONIC MEASUREMENT OF PARTICLE SIZE DISTRIBUTION

摘要

A method and apparatus to measure the particle size distribution of particles in suspension provides generating an interrogating ultrasonic signal consisting of tone bursts of a defined frequency into a fluid suspension, wherein the fluid suspension is in motion or is caused to become in motion by the interrogating signal or other methods wherein induced particle velocity is a unique function of particle size; measuring the backscattered ultrasound from the interrogating signal; converting the backscattered ultrasound to a high resolution, backscattered spectrum represented by a narrow bin- width histogram in terms of the Doppler shift of frequency away from that of the interrogating signal; assigning a particle size to each bin of the spectrum by reference to a separately constructed calibration curve or relationship of particle size as a function of Doppler frequency shift; and transforming the value of the ordinate of each bin in the backscattered spectrum to a measure of the relative particle concentration in each bin by scaling using functions of the particle size associated with that bin and of the value of the ordinate of that bin to produce a particle size distribution relating the relative concentration of particles in suspension to particle size.