System and filter cartridge with a granular and cellular material

摘要

The filtration system uses as filter medium granules of inert pozzolana (volcanic ash) of honeycomb structure, of density less than 1 and grain size up to 25 mm, enclosed in a casing (4,15) through which fluid is directed. Also claimed is the use of the above material as the sole medium to filter fluid which is directed through it.