MICROSCOPIC OBSERVATION OF FILTER CAKE FORMATION

Particle collisions and filter cake collapse are observed through a mi croscope during the formation of filter cakes. Cake filtration is wide ly applied throughout industry for fluid-particle separations. Models and theories have been developed to describe and predict filter cake p erformance, but there is little literature on direct observation of pa rticle packing and cake formation. A filter assembly the size of a mic roscope slide is placed on the microscope such that the slurry flow an d cake formation is across the field of view. The cake formation is re corded on video tape. Photographs of the video image show particles in the slurry colliding with and sometimes adhering to other particles w hen forming the filter cake. The photographs also show the cake struct ure collapse as the cake compacts or compresses.