Mechanical expression, stresses at cake boundaries and new CP cell

Expression or squeezing operation under constant pressure was analyzed taking into account the medium resistance. A nonlinear partial integro-differential equation representing the squeezing operation was solved using numerical methods. A computer program was developed to calculate transient pressure profiles and the cake thickness as a function of time. The problem was solved in two different coordinate systems. Apparatuses were developed to measure the stress distribution on the boundaries of filter cakes compacted under mechanical pressure. It was discovered that for thin cakes the stress distributions on the bottom and at top are bell-shaped and not flat profiles as assumed by investigators in this field. An improved compression-permeability cell was developed. In this apparatus, the hydraulic pressure profile was measured inside the cake at the center and at the wall. The filtration resistance was determined from slopes of the curved profiles. Previous calculations have been made on the assumption of linearity of hydraulic pressure.