Thin-cake thickener

Figure 19, Principal components of a staged, thin-cake filter thickener.

The combination of hi pressure (300 psi) and thin cakes produces high rates. Washing is accomplished either cocurrently or countercurrently. Separate filters in series can be employed in a manner similar to conventional thickeners. Washing may also be performed within a single unit, whereby, an initial portion of the filter must be used to remove liquid. In this case, the final stages are used for concentration. Clean wash liquid may be injected after the initial filtering at one or several intermediate stations. Injection wash tends to increase the overall filtrate rate but decreases the cake ouqtut rate. 

Dynamic thickeners have become a popular machine option. Special dynamic elements housed inside a thickening chamber keep the slurry continuously moving hence, a concentrate of a paste-like consistency is possible without the danger of filter blocking. High flowrates per unit area, resulting from very thin cake formation, allow such units to be designed of relatively small size. 

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