Patent ID: 6225125
Filing Date: 2001-05-01
Classification: C12M,G01N,Y10T

Abstract:
A method for collecting for image analysis a selected quantity of particles having a known average size above a threshold size and that are in a fluid medium, comprising the steps ofA. providing a flow path for the fluid medium, with the particles carried therein, across a filter device having a substantially uniform distribution of apertures of substantially uniform size for blocking particles above said threshold size and passing smaller particles,B. applying a selected fluid signal to the flow path for producing flow of the liquid medium through said filter device, said signal-applying step including applying a succession of signal pulses to the fluid, including across said filter device,C. measuring a parameter responsive to fluid flow through said filter device due to said applied fluid signal and which changes according to blockage of said filter device by particles above said threshold size,D. terminating said fluid signal in response to a selected change in said measured parameter, andE. transferring the particles collected on said filter device, after said selected change in said measured parameter, to an optical element for image analysis.