Patent ID: 6205848
Filing Date: 2001-03-27
Classification: G01N

Abstract:
Method for the detection and identification of particles in a suspension, comprising the following steps:a. generation of acoustic signals using an acoustic source;b. directing the acoustic signals at at least one measurement volume within the suspension, the measurement volume having boundaries in an axial direction with respect to the acoustic source that are defined with the aid of time windows;c. reception of acoustic reflection signals produced by reflection of the acoustic signals by the particles in the at least one measurement volume;d. conversion of the acoustic reflection signals into electrical reflection signals;e. counting numbers of electrical reflection signals which have an amplitude in excess of a predetermined value and conversion thereof into numbers of particles which are larger than a certain size;wherein the method also comprises the step of applying an inversion algorithm on the amplitudes of the electrical reflection signals to deduce at least one feature from a set of features comprising: material properties, particle concentration, particle shapes, particle size and standard deviation thereof and particle size distribution, the inversion algorithm resulting from inverting a predetermined forward model which describes the amplitudes of the electrical reflection signals as a function of the properties of the suspension and the acoustic signals generated by the acoustic source; andwherein the inversion algorithm being based on the relation between particle size distribution and a probability density function p(A) for the amplitude A, where p(A) is defined as:p(A)=.intg.g(A.vertline.D)h(D)dDwhere:g(A.vertline.D)= probability density function for a measured amplitude A for a particle of given diameter D,h(D)= probability density function for particle diameter D, the equation being integrated between two predetermined limits for particle diameter.