The invention relates to a filter device for a plastic melt or another highly viscous fluid, comprising a housing with an inlet plate and a discharge plate. At least one spacing element and a screen wheel which can be rotated by a drive device are arranged between the inlet plate and the discharge plate. The inlet plate and the discharge plate are clamped against each other with the inclusion of the spacing element via at least three housing clamping elements. An engagement point of the drive device on the screen wheel is arranged outside of the pretensioning surface. When viewed in the rotational direction, an angle α larger than 110° and smaller than 160° is formed on the screen wheel between a first line that extends between the pretensioning surface centroid on which a resulting frictional force F.sub.R acts and the center of the screen wheel and a second line between the center and the engagement point on which an advancing force Fv acts.

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 partialisations of the perforated disk (11) associated with the outlet section (12a) of the seat (9).

The invention relates to a melt filter (1) for filtering plastic melts, comprising a screen rotor (3) which is arranged such that it can be rotationally driven between two housing plates (2) and which has recesses (5) along a circular path (4) for receiving exchangeable filter elements (6), and comprising a melt channel (7) which penetrates the housing plates (2) in the region of the circular path (4) and is associated with the screen rotor (3). In order to create advantageous conditions, it is proposed that the screen rotor (3) comprises two axially spaced rotor cheeks (9) which are provided opposite one another with filter elements (6) through which the plastic melt can flow and towards which the melt channels (7) of the two housing plates (2) open out, wherein at least one collecting chamber (10) for plastic melt filtered by the filter elements (6) is provided in the screen rotor (3) between opposing filter elements (6), and wherein a flow channel (11) opening out of the screen rotor (2) in the region of the rotor axis (8) is provided for discharging filtered plastic melt from the collecting chamber (10).

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.

The invention relates to a filter device for a plastic melt or another highly viscous fluid, comprising a housing with an inlet plate and a discharge plate. At least one spacing element and a screen wheel which can be rotated by a drive device are arranged between the inlet plate and the discharge plate. The inlet plate and the discharge plate are clamped against each other with the inclusion of the spacing element via at least three housing clamping elements. An engagement point of the drive device on the screen wheel is arranged outside of the pretensioning surface. When viewed in the rotational direction, an angle α larger than 110° and smaller than 160° is formed on the screen wheel between a first line that extends between the pretensioning surface centroid on which a resulting frictional force F.sub.R acts and the center of the screen wheel and a second line between the center and the engagement point on which an advancing force F.sub.V acts.

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

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

A continuous screen changer, including: an external shell having an internal cavity, and an internal drum. The external shell is provided with a feed port, a screen changing port, and a discharge port. The internal drum is provided with at least four filter screen mounting grooves and material flow passages correspondingly communicating with the filter screen mounting grooves. A sealing wall hermetically connected with the internal cavity is formed between each two adjacent filter screen mounting grooves. Whichever of the filter screen mounting grooves is opposite to the feed port rotates to be opposite to the screen changing port in a rotation process, and whichever of the filter screens is on said filter screen mounting groove opposite to the screen changing port is changed at the screen changing port

Disclosed are a continuous screen changer, a screen changing device, and an extruder. The continuous screen changer includes an external shell with an internal cavity and an internal drum; the external shell is provided with a feed port, a screen changing port and a discharge port. The internal drum is provided with at least four filter screen mounting grooves and material flow passages correspondingly communicating with the filter screen mounting grooves, and a sealing wall hermetically connected with the internal cavity is formed between each two adjacent filter screen mounting grooves. After entering the internal cavity along the feed port and being filtered by a filter screen, materials flow out of the discharge port along the material flow passages. The filter screen mounting groove rotates to be opposite to the screen changing port, and the filter screen on the filter screen mounting groove is changed at the screen changing port. The continuous screen changer can implement continuous and uninterrupted change of the filter screens, so that the apparatus to which the continuous screen changer is applied can continuously work.

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).