Patent ID: 6230551
Filing Date: 2001-05-15
Classification: G01N

Abstract:
A method of evaluating particulate contaminants in a fluid comprising:providing a flow of particulate-containing fluid through a first screen having apertures of a single predetermined size for filtering particulate contaminants larger than the predetermined size;determining when the pressure drop across the first screen reaches a predetermined maximum corresponding to blockage of the first screen;after determination of blockage, providing a reverse flow of clean fluid through the first screen and then flowing the reversed clean fluid with the particulate contaminants from the first screen through a second screen having apertures of a predetermined size greater than the predetermined size of the apertures of the first screen;providing a flow of the particulate-containing fluid through the second screen;determining the greatest pressure drop during the particulate-containing fluid flow through the second screen;providing a flow of a clean fluid without the particulate contamination through the first screen;measuring the pressure-drop across the first screen during the clean fluid flow;providing a flow of the clean fluid without the particulate contamination through the second screen;measuring the pressure drop across the second screen during the clean fluid flow; anddetermining from the pressure drops the number of particles in the fluid greater than the size of the apertures of the first screen and the number of particles greater than the size of the apertures of the second screen.