Pressure filtration tests of liquid Al-Si cast alloys II. Best-fitted equations for filtrate weight versus filtration time curves

Though the cake mode generally dominates the Prefil Footprinter (R) tests, the filtrate weight versus filtration time curves deviate, to some extent, from conventional filtration equations at constant pressure. This work attempts to seek other models for the Prefil Footprinter (R) curves. It is interesting to find that there is a good linear relationship between In(weight, in grams) and In(time, in seconds) over the whole course of the filtration period, i.e. filtrate weight can be best expressed as a power function of filtration time. In the presence of the complete blockage stage, the filtrate weight or In(weight) appears to be a line paralleling to X-axis at this substage. The physical mechanism for the model is not known at the moment. The Prefil Footprinter (R) filtrate weight versus filtration time curves will never be convex, i.e. they appear as concave and/or straight lines. (c) 2005 Elsevier B.V. All rights reserved.