An extruder (20) is specifically designed for the production of animal feed products (e.g., aquatic feeds) containing substantial quantities of low-cost fibrous materials, such as rice byproducts, at high production rates. The extruder (20) includes an elongated barrel (22) with a screw assembly (24) within the barrel and an endmost extrusion die assembly (34). The screw assembly (24) includes an inlet screw assembly (42) and a processing screw assembly (44). The assembly (44) includes screw components (50-56) of differential pitch to present a long pitch inlet section (64) and a tight pitch discharge section (68). Materials passing through the screw assembly (24) are successively subjected to high levels of steam injection (STE) followed by high levels of friction and shear (SME), so that the STE/SME ratio is at least about 6/1.

In a method and an apparatus for increasing the intrinsic viscosity of a polycondensate melt at negative pressure, the melt enters a chamber, in which a negative pressure of less than 20 mbar prevails, through a perforated plate or a screen having openings with a diameter of less than 0.5 mm. The melt passes through this chamber in free fall in thin threads and remains in a reservoir beneath the chamber for at least one minute. The melt is moved constantly in the reservoir, and discharged from the reservoir, by a helical mixing and discharge part.

The invention relates to novel screw elements for multi-screw extruders with screw profiles co-rotating in pairs and being fully self-wiping in pairs, to the use of the screw elements in multi-screw extruders and to a process for extruding plastic compositions.

The present invention relates to screw elements with novel, tightly intermeshing, self-cleaning, co-rotating screw profiles for multishaft screw machines with pairs of co-rotating and fully abrading screw shafts, to the use of these screw elements in multishaft screw machines and to a method of generating these screw elements.

The present invention relates to a process for devolatilising polymer-containing media such as, in particular, polymer melts, polymer solutions and dispersions and also devolatilisation apparatuses for carrying out the abovementioned process.

The kneading apparatus 1 includes a casing 2, a pair of elongated screws 4a, 4b rotatably provided in the casing 2. The screws 4a, 4b are arranged parallel and horizontally with respect to one another. The casing 2 has a main body 20 and a screw container 3 provided in the casing 2. The screw container 3 defines a kneading section 30 therein. The screw 4a includes a screw axis 41 having an outer periphery, a first screw member 42 provided on the outer periphery of the screw axis 41 and a kneading member 43 provided on the outer periphery of the screw axis 41. The first screw member 42 and kneading member 43 are provided in the kneading section 30. The screw 4a, the first screw member 42 and the kneading member 43 respectively have core portions 411, 412, 413 having a surface and outer layers 45 respectively provided on the surfaces of the core portions 411, 412, 413. The screw container 3 and the outer layers 45 are constituted of a nonmetallic material.

The present invention relates to new screw elements for multi-screw extruders with pairs of co-rotating and fully wiping screws.

An Extruder for providing a flow of viscoelastic material such as rubber is disclosed herein. The extruder includes several zones (A, P, H, S), each assigned to a particular rheological function and arranged axially from an upstream end to a downstream end of the extruder and having an endless screw of given diameter (D). In each of the zones, at least one helicoidal flight extends radially from a central shaft of the screw over a height (h.sub.1), in a direction and with a pitch which are defined for each of the zones, and which is rotationally driven about an axis (XX) in a barrel. The barrel is provided with various structures to further assist with the flow of the viscoelastic material

The present invention relates to a process for devolatilising polymer-containing media such as, in particular, polymer melts, polymer solutions and dispersions and also devolatilisation apparatuses for carrying out the abovementioned process.

The invention relates to an apparatus and a process for producing pigment-containing, in particular carbon-black-containing, polymer mixtures comprising polycarbonates and optionally elastomers, and/or other components, where the mouldings produced therefrom have, after the shaping process via injection moulding or via extrusion, improved surface properties and improved mechanical properties.