TABLE OF CONTENTS Although the main purpose of this chapter is to present design procedures for batch filter cycles, the methodologies described can be adapted to the operations performed in a batch centrifuge and by way of example Figure 6.10 illustrates a typical peeler centrifuge cycle. During the filtration of a suspension batch, the perforated basket covered by a filter cloth is rotated at a constant speed and the induced centrifugal forces cause the centrate to pass leaving the filtered particles to form the cake. Following the completion of cake formation, the cake may subsequently be washed by sprays and/or allowed to deliquor prior to discharge by mechanical plough or peeler. With centrifugal filters the filtration area is a function of time and for a peeler centrifuge the equation relating filtrate flow rate ( q) to cake growth is
where ? is the angular velocity of the basket, r 0 the inner radius of the basket, r l the radius of the liquid layer, r c the inner radius of the cake and h the basket depth. Noting that the average flow area ( A f) av = ?h( r 0 + r c) and the logarithmic mean flow area ( A f) lm = 2 ?h( r 0 ? r c)/ln ( r 0/ r c), equation (6.88) may be rewritten as
