Filter device (1) for filtering extruded polymers comprising a containment body (2) defining at least one cavity (3), an inlet opening (4) in fluid communication with the cavity (3) via a respective inlet conduit (5), and an outlet opening (6) in fluid communication with the cavity (3) via a respective outlet conduit (7), and a support body (8) slidably inserted in the cavity (3) and interposed between the respective inlet conduit (5) and the respective outlet conduit (7) and having a seat (9) for housing a filter assembly (10) consisting of two perforated disks (11) and a filter screen located between the two perforated disks (11). The seat (9) has an inlet section (13a) having dimensions equal to an outlet mouth (5a) of the inlet conduit (5), and an outlet section (12a) with dimensions that are larger than the dimensions of the inlet section (13a) and equal to a maximum extension of an inlet mouth (7a) of the outlet conduit (7). The support body (8) is slidably movable in the cavity (3) along a main direction of movement (L) so as to produce different partializations of the perforated disk (11) associated with the outlet section (12a) of the seat (9).

A method and an apparatus for operating a screening wheel filter for high-viscosity melts with pressures of >10 bar and temperatures of >90 C., wherein a screening wheel (1) is rotationally driven step by step, and screening inserts (2) arranged in the screening wheel (1) are successively subjected to a stream of cleaning agent produced by a cleaning agent drive (9) in a backflushing cleaning station, are to be optimized in such a way that less cleaning agent is used, better cleaning of the screening inserts takes place and a saving of energy is ensured. For this purpose it is proposed that the cleaning backflushing in the backflushing cleaning station takes place during the rotation of the screening wheel (1), wherein an open-loop or closed-loop control device (7) assigned to the cleaning agent drive (9) is used to set the amount of cleaning agent and/or the pressure of the cleaning agent and/or the flow rate of the cleaning agent in dependence on the rotational speed of the screening wheel (1) and/or in dependence on a differential pressure prevailing at the screening inserts (2) located in the melt channel (4) and the effective opening of the slot die normal to the radial is less than the distance covered by the screening wheel (1) during a driving step.

A filtering device for high-viscous fluids having a two pistons being movably disposed in bores is disclosed. Each piston has at least one cavity and at least one filter element. The device also includes a displacing piston for generating fluid pressure and reversing the flow direction at the fluid during a back-flushing mode in an outlet channel or in a reservoir connected therewith.

The invention relates to a device and a method for filtering viscous or highly viscous liquids, in particular plastics melts, using an oscillating filter plate.

In one example, a filtering device has a housing that defines an inlet opening, first and second bores with first and second pistons therein, respectively, first and second inlet channels that extend from the inlet opening to the first and second bores, respectively first and second outlet channels in communication with the first and second bores, respectively, and a first backflush channel. The first piston defines a filter cavity in fluid communication with the first inlet and outlet channels when the first piston is in a production mode. The second piston defines a filter cavity in fluid communication with the second inlet and outlet channels when the second piston is in the production mode. The device has a backflush valve that compresses fluid into the filter cavity of the first piston via the first backflush channel to increase pressure in the cavity during a backflushing operation.

A filtering device for plastic materials in a molten state includes two filters made of a metal mesh and arranged side by side inside a filtration chamber, and a cleaning device between the two filters, the cleaning device in turn including one or more pairs of main hollow bodies provided with adhering walls that adhere to the filters or holed supports of the filters.

A filter candle to separate contaminants from a plastic melt is disclosed. The filter candle has a filter element through which a melt flow is directed to retain contaminants contained in the melt flow, and a supporting body to support the filter element. The supporting body is a hollow body having multiple passages for the melt flow. At least one additional supporting body is on the side of said filter element that faces away from the supporting body. The additional supporting body acts on surface regions of the filter element and/or accommodates them such that the filter element can be backwashable.

The present invention relates to a filtering device for fluids, in particular thermoplastics, comprising a screen carrier (2) which has a rotationally cylindrical outer face (41) and is mounted rotatably in a rotationally cylindrical recess (5), adapted to its circumference, of a stationary housing (3) and in which a number of screening nests (6) having filter arrangements (7) are formed along its circumference. According to the invention, there is provision whereby the screen carrier (2) is penetrated by a rotationally cylindrical core part (1) and is mounted rotatably on this, the core part (1) and the housing (3) being designed to be stationary and fixed in terms of rotation with respect to the rotatable screen carrier (2).

The invention relates to a device (2) for filtering a liquid plastic, with a housing (4) with an inlet (6) for introducing the plastic and an outlet (8) for discharging the plastic, a screen carrier (12) accommodated in the housing (4) and having a screen chamber (10) for accommodating a filter element (14), a filter element (14) arranged in the screen chamber (10) of the screen carrier (12) and having a filter side (16) and a clean side (18), the filter element (14) being connectable to the inlet (6) and the outlet (8) in such a way that the plastic passes through and is filtered by the filter element (14) in a filtering flow direction (56) from the filter side (16) to the clean side (18) and wherein the filter element (14) can be cleaned by backwashing by plastic flowing counter to the filtering flow direction (56), a backwashing feed channel (20) fluidly connected to the clean side (18) of the filter element (14), which feed channel (20) is set up for this purpose, the filter element (14) against the direction of filtration flow (56), and a backwash discharge channel (22) which is fluid conductively connected to the filter side (16) of the filter element (14) and which is arranged to discharge the backwashed plastic after it has passed the filter element (14). According to the invention, a backwash screen support (24) fluidly connected to the backwash discharge channel (22) is proposed, comprising a screen chamber (26) for receiving a backwash filter element (28) and a backwash filter element (28) arranged in the screen chamber (26) and adapted to filter the backwashed plastic.

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.