Precoat filtration with filter aids
Filtration is one of the most common application technologies to separate suspensions of solid and liquid components. Whenever liquids with an extreme blank filtration are involved, precoat filter systems have always proven their value during the last decades. A distinction is made between pressure and vacuum filters of different designs in which the filter elements are covered with fabrics, mainly synthetic fibers or metal. Porous materials also serve as filter elements.
As a rule, turbidities in the liquid to be clarified are small and compressible. They settle like a film on the filter elements and very rapidly clog them or they pass through the filter and remain as turbidity in the filtrate or end product. In order to avoid this and ensure that filtration is economically efficient, filter aids like diatomaceous earth, perlite and cellulose are used. They take over the actual filtration task; the filter elements serve exclusively as carriers for the deposited filter aids.