Stainless Steel Food Beverage Plate Frame Press Filter Operation principle The suspension is delivered to each sealing chamber by pump, under pressure, the filtrate passes the filtering layer and screen filter or other filter material, and is discharged by liquid outlet. In the steel frame, the filter residue is stored and becomes filter cake. 2. Stainless steel multilayer frame filters are widely used in medicine, food, chemical, water treatment, electronics, textile, and plating industries.