Police filter is intended for catching of small amounts of solid particles (dross, rust, filtering powder, etc.) accidentally ingressed in liquids (plant oil, juices, water, beer, syrups, etc.), which were purified on the other filters, i.e. for performing safety ("police") functions. Police filter is a cylindrical tank with a removable cover and with the filter material inside.
Liquids are filtered through a layer of nonwoven heat sealed or needled material (police filter element) with selectivity of 5-25 mkm.