The Analysis of Dust Cake Structures

The operational characteristics of cake‐forming filter apparatus are strongly influenced by the structure of the dust cake formed. The quantitative evaluation of sectional images of loosely bound filter cake deposits is introduced. First the techniques with which the dust cake is prepared and with which scanning electron micrographs may be obtained are described, together with the subsequent digitization by video and computer equipment. This is followed by a comprehensive description of the evaluation of the digitized images, with special emphasis on the determination of the deposit's porosity and the computation of the particle and pore‐size distributions at selected locations. Finally, results derived from a true filter cake are presented.