Centrifuge as well as insert and base element for a centrifuge

The invention relates to a centrifuge used for cleaning a liquid to be cleaned, particularly to a free jet centrifuge used for cleaning lubricating oil of an internal combustion engine. The centrifuge has a rotor (10), wherein the rotor (10) includes a radially internal rotor shaft (11), a radially external rotor cylinder (12) and an insert (16) arranged between the rotor shaft (11) and the rotor cylinder (12) and having a deposition surface (17) used for pollutants, wherein the insert (16) can be flown over axially by the liquid to be cleaned. The insert (16) includes a plurality of concentric walls (18, 19, 20), i.e., a tubular inner wall (18), a tubular outer wall (19) and a plurality of tubular intermediate walls (20), which are connected through connection pieces (21) extending in a radial direction. In addition, the rotor includes a base element (22), wherein the base element (22) includes recesses, and the sizes of the recesses are such designed so as to be permeable to liquid but impermeable to most o