Other Modes of Filtration

In 1936 Hermans and Bredee published the results of their investigation into the various filtration modes. Hiis was later con rdiaisively reviewed, sununarised and tested by Grace [1956]. The diftermit modes of filiation reflect not only the concentration of suspension but also the mechanism pertaining. These include  

The cake filtration mechanism has already been explained in Section 2.4. The following discussion refers mainly to other types of filtration which can occur very early on in the otherwise cake filtration cycle, or over a prolonged period during clarifying filtration. 

The mathematical descrption of the different filtration modes is based on a common differential equation with two constants n and K  

For exan le if the data provides a straight line on a plot of inverse instantaneous flow rate q i ainst time t then an intermediate blocking model is apparent, or a hnear relation on a plot of time over cumulative filtrate volume t/V against time t suggests standard blocking. 

Standard blocking has been reported to be an appropriate filtration model for cartridge filtration of liquids and a form of the standard blocking equations shown in Table 2.3 has been used to correlate the filtration of viscose and cellulose acetate [Grace, 1956]. The model assumed in the derivation of the standard blocking equations is that 

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