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 filtration device for extrusion processes, which comprises a material intake channel, which splits into a first intake channel and a second intake channel leading to a first filter chamber and a second filter chamber, the first and second filter chambers being provided in output with a first output channel and a second output channel, which in turn merge into a channel that is adapted to convey the material to an extrusion head.

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).

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.

A method and a filtration system filter liquids and/or melts. The filtration system includes a housing with a supply channel, a discharge channel and a first and second filter device. Each of the filter devices has a filter element passed through a filter chamber, which is held clamped by clamping devices. Each of the clamping devices includes interacting clamping elements and actuating elements, wherein the clamping elements are guided in a normal direction onto a flat side of the respective filter element in an adjustable manner relative to the housing. Clamping element contact surfaces and actuating element contact surfaces are respectively aligned opposite to one another and have an oblique longitudinal alignment with respect to the flat side of the respective filter element.

A method and a filtration system filter liquids and/or melts. The filtration system includes a housing with a supply channel, a discharge channel and a first and second filter device. Each of the filter devices has a filter element passed through a filter chamber, which is held clamped by clamping devices. Each of the clamping devices includes interacting clamping elements and actuating elements, wherein the clamping elements are guided in a normal direction onto a flat side of the respective filter element in an adjustable manner relative to the housing. Clamping element contact surfaces and actuating element contact surfaces are respectively aligned opposite to one another and have an oblique longitudinal alignment with respect to the flat side of the respective filter element.

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.