Dislodging of cake by reverse flow

This is a method limiting cake thickness by intermittent back-flushing of the filter medium, as reported by Muira and Brociner , for example. Conventional vacuum or pressure filters can be used with some modifications for the effects of the forces of the back-flush. Thus filtering through thin cakes in short cycles can be used. 

Sawyer has patented a similar pressure filter, also tubular, in which the filter blanket in the form of a membrane is constantly cleaned by a sonic sinusoidal wave. This is induced by a transducer which is affixed to the tubular wall at an antinodal point and which causes cavitation and continuous cake removal within the annular filtration chamber. This invention is specifically related to the membrane process of filtration, such as ultra-filtration reported in the following section. 

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