Comparison of the specific resistances of cakes formed in filters and centrifuges

Resistances to the flow of fluids through porous beds were determined in a compression‐permeability cell, a vacuum test filter, and an experimental centrifugal filter. The study was made on nearly incompressible beds composed of Lucite spheres having a given size distribution. The results show that liquid flow through the cakes in all three kinds of equipment can be described by a common basic equation, the terms of which are modified to reflect the type of operation. The centrifugal‐drainage data confirm the form of the centrifugal‐filtration equation. The specific resistances deduced from vacuum‐filtration and centrifugal‐drainage tests agree with permeability‐cell alphas within 16% at the same Δ P and within 2 to 3% at the same porosity.