An automatic screen changer device for use on systems and equipments for the manufacturing, processing, recycling and treatment of thermoplastic materials, is placed downstream of an extruder device and includes a frame (12), two opposite side plates or shoulders secured to the frame and provided, respectively, with an inlet opening (18) and a pair of inlet channels (30), with an outlet opening (20) and with a pair of outlet channels (32), the inlet channels allowing a flow and a screening of contaminated molten material in the direction of the outlet channels through a pair of stacked screening units; the device likewise includes movable sealing and locking/unlocking elements of a screening support or band for the screening of the molten material in each screening unit with the latter movable reciprocally with temporary interruption of the flow of molten material through one of the same screening units during the screen change.

A discharge method and a discharge device for a cleaning device (2) for filters (5, 6), includes a supply line (26) which can be connected to a collection region (23) for removed filter residue (9) of the cleaning device (2). The discharge device (3) has a controllable metering device (4) which adjoins the supply line (26) and which blocks the supply line (26) and receives removed filter residue (9) from the supply line (26) in portions (35) in a meterable manner and discharges same at a different location. For this purpose, the metering device (4) has a metering element (28) which can be moved in a controllable manner, in particular a rotatably and/or movably arranged metering element. The filter residue (9) can be removed from the filter (5, 6) via a backflushing process or in a mechanical manner using a scraper or the like.

The invention relates to a filtering device for filtering a fluid, and in particular a liquefied plastic. The filtering device includes a control unit to control the position of a screen carrier by generating control signals such that the fluid pressure in a fluid inlet channel and/or in a fluid outlet channel remains within definable pressure ranges while a cavity is being filled.

A device (1) for filtering plastic melt having an inlet valve (14), an outlet valve (15) and a filter canister (2), wherein a cavity (3) closable by means of a cover (4) is formed and into which a melt channel (20) opens. In the filter canister (2) there is arranged a plurality of filter cartridges (5), which are each formed by a filter substrate (6) and a filter lattice (7). The filter substrate (6) comprises a wall having openings, said wall defining an internal space (8), which opens through an outlet (9) into a collection channel (10). The filter lattice (7) covers the openings of the filter substrate (6). The melt channel (20) is adjacent to the inlet valve (14) and may be brought into fluid communication with an outlet channel (16) via the inlet valve (14). The collection channel (10) is adjacent to the outlet valve (15) and may be brought into fluid communication with an outlet channel (18) via the outlet valve (15). The cover (4) fixes the filter lattices (7) onto the filter substrates (6).

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.

The invention relates to a filter device comprising an inlet chamber, an outlet chamber, a filter system which separates the inlet chamber and the outlet chamber. The filter device is characterised in that the inlet chamber comprises at least one liquid supply line and at least one liquid discharge line and the outlet chamber does not comprise a liquid supply and comprises at least one liquid discharge line. The invention also relates to a corresponding filter method.

The invention relates to a method and to an assembly for recycling plastic materials, comprising the following processing steps: a) reprocessing the raw material, wherein the material, if necessary, is comminuted and brought into a fluid-like form and heated and permanently mixed, while preserving the lumpiness and pourability thereof, and optionally the viscosity thereof is increased and/or it is degassed, softened, dried and/or crystallized; b) melting the reprocessed material, at least so much that filtration is possible; c) filtering the melt in order to remove impurities; d) homogenizing the filtered melt; e) degassing the homogenized melt; and f) discharging and/or subsequently processing the melt, such as by granulation, blown film processing, with said processing steps being carried out consecutively in the order listed (FIG. 2).

A device for filtering a plastic melt, including a housing and a filter pin which is axially and/or radially movable therein. In a working position of the filter pin, plastic melt passes from an inlet channel, through a filtering mechanism, which is detachably fastened to the filter pin, to an outlet channel. In a filter change position of the filter pin, the filtering mechanism is freely accessible for replacing the filtering mechanism, and wherein at least one drainage channel is formed in the filter pin. In a start-up position of the filter pin, one end of the at least one drainage channel is in fluid connection with the at least one inlet channel in order to receive the plastic melt that is fed through the at least one inlet channel and to output the plastic melt at another end of the at least one drainage channel.

A film blowing machine for producing a film web from a recycled material having a.-an extruder for melting and homogenizing the recycled material into a melt, b. an annular die for extruding a film tube, c. a guide for a melt flow between the extruder and the annular die via an annular die melt pump, for conveying the melt to the annular die, d. a tube-forming zone for longitudinal and transverse drawing of the film tube, e. a cooling means for the film tube moving in the machine direction, f. a flattening unit on the other side of the tube-forming zone for flattening the film tube into a double layer film web, g. a pair of draw-off rollers on the other side of the cooling means for drawing off the film tube, and h. the extruder is designed as a twin-screw extruder.

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.