In one example, an apparatus for filtering a fluid (e.g., a plastic melt having impurities) includes a housing which has at least one inlet for introduction of the fluid and an outlet for delivery of the fluid and a cavity formed in the housing by wall portions of the housing for receiving a sieve support, and a sieve support which is arranged moveably in the cavity of the housing and has a longitudinal axis for receiving at least one filter element for filtering the fluid. The sieve support externally has a plurality of integrally formed raised portions and/or raised portions and/or recesses are formed at wall portions of the housing, that delimit the cavity, such that provided between the wall portion and the sieve support are a plurality of gaps/cavities, by means of which a slight fluid flow is enabled in operation. Another example concerns a valve arrangement.

Modular fluid processing apparatuses, modular components and related methods are provided. A fluid processing apparatus for use in fluid processing systems can include a housing comprising first body half and a second body halves that are secured together. The first body half has one or more half bores that extend along a length of the first body half and the second body half has one or more half bores that extend along a length of the second body half with the one or more half bores in the first body half aligning with the one or more half bores in the second body half forming one or more full sleeve-receiving bores. The fluid processing apparatus can include one or more sleeves that are securable between the first and second body halves within the one or more sleeve-receiving bores to form piston pathways within the housing for receiving pistons.

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.

A method for directly preparing a foamed polylactic acid (PLA) product from a PLA melt includes PLA melt preparation, feeding, and two-stage extrusion. In the two-stage extrusion, a pressure at an outlet of a first-stage twin-screw extruder is 15 MPa to 17 MPa, a PLA melt is fed at a rate of 250 kg/h, a foaming additive is fed at a rate of 7.5 kg/h to 10 kg/h, and a foaming gas is fed at a rate of 2.8 L/h to 7.5 L/h. The method can ensure both foamability and quality of a material and reduce more than ⅓ of energy consumption; and an obtained product has an adjustable foaming rate of 3 to 25, a crystallinity of 40.3% to 48.5%, a tensile strength of 8.7 MPa to 19.6 MPa, and an apparent density of 0.05 g/cm.sup.3 to 0.4 g/cm.sup.3.

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 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 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.

Extrusion die systems, die changers and related methods are provided herein. The die changer for changing of dies in and out of an extrusion line can include a housing having a main supply feed bore therethrough for directing a flowable material and a channel oriented transversely to the main supply feed bore. The die changer can include a slide plate movable through the channel and transverse to a direction of flow through the bore. The slide plate can include an elongate body having a first section and a second section. A first bore can extend through the first section of the elongate body of the slide plate and a second bore can extend through the second section of the elongate body of the slide plate. The slide plate of the die changer can be moved within the channel of the housing between a first position where the first bore in the first section of the elongate body of the slide plate is aligned with the main supply feed bore and a second position where the second bore in the second section of the elongate body of the slide plate is aligned with the main supply feed bore.