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 polymer melt candle filter having a support which comprises a hollow cylindrical body defined by a first end, a second end, and a cylinder wall having a first end portion and a second end portion. The first end portion includes a screw thread on its outside surface and optionally a hex fitting on its inside surface for receiving a hex wrench. The second end portion includes a plurality of holes in the cylinder wall. The area of the openings of the holes on the outside surface of the cylinder wall may be larger than the area of the openings of the corresponding holes on the inside surface of the cylinder wall. The shape of the openings of the holes on the outside surface may be non-circular. A polymer melt filter plate assembly which comprises (a) a support plate comprising a plurality of threaded holes; (b) at least one filter which is screwed into at least one of the threaded holes via the screw thread on the outside surface of the first end portion of the filter support; (c) a tie rod with (i) a first end extending through a hole in a cone insert and a cap located at the second end of the filter support, and (ii) a second end extending through a threaded hole in the support plate; and (d) a cross bar which is attached to the second end of the tie rod for holding the support plate inside a shaft of an apparatus for filtering a polymer melt.

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.

On a rotary screen filtering device for medium to high-viscosity fluids, which comprises a rotary screen mounted for rotation in a housing, which screen has at least one screen element through which fluid can flow, the rotary screen, in the region of its sealing faces and the intermediate plates are fabricated or machined together so that they are of identical height. A gap width compensation layer is then inserted between the inlet plate and the intermediate plate and/or between the outlet plate and the intermediate plate. The package of plates is then pretensioned by means of screw bolts in such a manner that all the plates lie firmly against one another up to a maximum permissible operating pressure. Lubrication gaps of defined width are created between the sealing faces and the opposing inner faces of the inlet and outlet plates.

Filtration apparatuses and screen changer devices for filtering polymeric material as well as spacer plates, and face plates for the screen changer devices and related methods are shown and described herein.

Filtration apparatuses and screen changer devices for filtering polymeric material as well as spacer plates, and face plates for the screen changer devices and related methods are shown and described herein.

A filter unit for an extruder assembly comprises a support body with a hollow cylindrical wall section and a base section connected thereto, wherein the support body has a central longitudinal axis and delimits an inner space, wherein the hollow cylindrical wall section has a plurality of through openings opening into the inner space and forms an outlet opening for a molten plastic opposite the base section; and a displacement element for displacing the molten plastic which has entered the inner space, in particular via the through openings, substantially in the direction of the central longitudinal axis, wherein the displacement element and the support body are configured and/or produced in one piece, as well as filter arrangement with a plurality of such filter units, filter changing device with at least two filter arrangements and method for producing such a filter unit.

A polymer melt candle filter having a support which comprises a hollow cylindrical body defined by a first end, a second end, and a cylinder wall having a first end portion and a second end portion. The first end portion includes a screw thread on its outside surface and optionally a hex fitting on its inside surface for receiving a hex wrench. The second end portion includes a plurality of holes in the cylinder wall. The area of the openings of the holes on the outside surface of the cylinder wall may be larger than the area of the openings of the corresponding holes on the inside surface of the cylinder wall. The shape of the openings of the holes on the outside surface may be non-circular. A polymer melt filter plate assembly which comprises (a) a support plate comprising a plurality of threaded holes; (b) at least one filter which is screwed into at least one of the threaded holes via the screw thread on the outside surface of the first end portion of the filter support; (c) a tie rod with (i) a first end extending through a hole in a cone insert and a cap located at the second end of the filter support, and (ii) a second end extending through a threaded hole in the support plate; and (d) a cross bar which is attached to the second end of the tie rod for holding the support plate inside a shaft of an apparatus for filtering a polymer melt.

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).

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.