The invention relates to a dirt precipitator (100) for a highly viscous medium, having a housing comprising a front housing element (30; 30) that comprises at least one inlet channel (33) and a rear housing element (20) that comprises at least one outlet channel (23), and having a screen wheel (10; 10) rotatably mounted between the housing elements (20, 30; 30) having a number n of screen positions disposed in a ring zone, on each of which at least one screen opening (11.1, . . . , 11.12) having at least one screen insert element is provided. The inlet channel (33), the outlet channel (23), and the screen opening (11.1, . . . , 11.12) are disposed flush one after the other in at least one working position and form a flow channel. In all positions of the screen wheel (10; 10), more than 50% of the screen openings (11.1, . . . , 11.12) are always able to be permeated, and are impinged by flow from at least one inlet channel and from which at least one outlet channel leads.

A filtering device for filtering a fluid, in particular a liquefied plastic, includes a housing having a receptacle for receiving a screen carrier and having a fluid inlet channel and a fluid outlet channel, a screen carrier movably received along a longitudinal axis inside the receptacle and having a screen carrier inlet, a screen carrier outlet and a cavity for receiving a filter element, wherein the cavity is in fluid communication with the screen carrier inlet and the screen carrier outlet, and the screen carrier can be moved from a screen replacement position via a venting position area into a filtering position. The screen carrier has a throttle recess which is arranged adjacent to the screen carrier outlet and is in fluid communication with the cavity, and which opens a variable flow cross-section between the cavity and the fluid outlet channel.

A method for operating a filter device for polymer melt to be filtered, said filter device incorporating at least one first large-area filter, which has a plurality of filter elements, in a first filter chamber; and a first drain for the filtered polymer melt from the first filter chamber. The polymer melt to be filtered is conveyed under pressure through the filter device. The polymer melt to be filtered is fed to the first large-area filter in the filter direction, and filtering is continuously performed via the first large-area filter. During a backflushing operation, at least one filter element is cleaned of impurities and backflushed by reversing the flow direction of the filtered polymer melt and passing it through the filter element.