Abstract: Described is a filter apparatus equipped with tubular filter elements comprising perforated pipe sections with filter media attached to their outer faces. The flow of the liquid to be filtered is directed onto the filter bodies transversely of the pipe section axis. The filter bodies are preferably disposed in a circular array and interconnected to form a cage acting as a rotor revolving within a casing supplied with the liquid to be filtered. A plurality of such cages may be concentrically nested within one another, with neighboring cages revolving in opposite directions. This results in the creation of pulsing flow patterns in the liquid to be filtered, which act to prevent premature clogging of the filter media by sediments thereon (FIG. 6).