A filtering device for removing dirt particles and contaminants from a plastic melt is disclosed. The filtering device includes a housing having a filter chamber, an inlet for feeding plastic melt, an outlet for channeling plastic melt out, and a dirt outlet for discharging dirt particles from the housing. The filtering device also includes a filter element arranged in the filter chamber to retain any dirt particles contained in the stream of melt, and a cleaning unit for cleaning the filter element of dirt particles retained by means of the filter element. The cleaning unit having a cleaning head with a scraper member for detaching dirt particles from the filter element. The scraper member is coupled to a servomechanism to press the scraper member onto the surface of the filter element. The servomechanism has at least one bellows cylinder including a foot section, a head section, a deformable bellows element, and a pressure chamber of variable volume.

A device for continuously filtering material mixtures, particularly for separating contaminants out of plastic melts, includes a filter (3), which is rotatably arranged in a filter chamber (2) of a housing (1), at least one wiper (17) for lifting off contaminants retained by the filter (3), and a discharge device (18) for removing the contaminants lifted off the filter (2) by the wiper (17) from the housing (1). The discharge device (18) includes a discharge shaft (19), which is rotatably arranged at the housing (1) and which has at least one continuous opening (20) having at least one piston (22) which is movably guided therein.

What is presented is a filter for plastic material, in particular a device that filters recycled plastic material, to clean it of extraneous bodies and foreign elements by means of several filtration units within a single body.

A device and a method for filtering viscous or highly viscous liquids, in particular plastics melts, includes use of an oscillating filter plate.

A filtering device for removing dirt particles and contaminants from a plastic melt is disclosed. The filtering device includes a housing having a filter chamber, an inlet for feeding plastic melt, an outlet for channeling plastic melt out, and a dirt outlet for discharging dirt particles from the housing. The filtering device also includes a filter element arranged in the filter chamber to retain any dirt particles contained in the stream of melt, and a cleaning unit for cleaning the filter element of dirt particles retained by means of the filter element. The cleaning unit having a cleaning head with a scraper member for detaching dirt particles from the filter element. The scraper member is coupled to a servomechanism to press the scraper member onto the surface of the filter element. The servomechanism has at least one bellows cylinder including a foot section, a head section, a deformable bellows element, and a pressure chamber of variable volume.

A device and a method for filtering viscous or highly viscous liquids, in particular plastics melts, includes use of an oscillating filter plate.

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.

A discharge device is for a filtering device for separating impurities from a material melt, in particular a low-viscosity polymer melt. The discharge device includes a discharge shaft with a pressure screw conveyor and a discharge head. Also disclosed is a filtering device including a cylindrical drum filter, a scraper and such a discharge device.

The invention relates to a filter device for polymer melts, having a filter screen (1), through which the polymer melt to be purified is guided, wherein the filter device comprises at least one scraping element (2), which glides across the upstream surface (4) of the filter screen (1) with its scraping edge (3), or rests on the surface (4) with its end area nearest the scraping edge (3), and lifts off and/or scrapes off the contaminations (6) adhering to the surface (4) and those present in front of the screen orifices (5) in the course of its movement across the surface (4). According to the invention it is provided that the scraping edge (3) has a curvature (7) at least in the end area of the same, leading in the direction of movement (16), the radius (R) of which is less than 90%, preferably less than 50%, in particular less than 20% of the maximum diameter, or of the maximum orifice width of the screen orifices (5).

A filtering device for a plastic material in the molten state includes a hollow body having a mouth and a cover; an inlet way and an outlet way for the filtered plastic material; two filters arranged side by side; a rotary cleaning device arranged between the two filters and provided with scraping elements cooperating with the filtering surfaces; and an evacuation device configured to discharge the impurities toward an evacuation outlet, the evacuation device being arranged centrally in such a way that the impurities travel along equal paths with the same flow rate and discharge the impurities in a balanced manner on the evacuation device.