High thermal transfer, hollow core extrusion screws (50, 52, 124, 126, 190) include elongated hollow core shafts (54, 128, 130, 192) equipped with helical fighting (56, 132, 134, 194) along the lengths thereof. The fighting (132, 134, 194) may also be of hollow construction which communicates with the hollow core shafts (54, 128, 130, 192). Structure (88, 90) is provided for delivery of heat exchange media (e.g., steam) into the hollow core shafts (54, 128, 130, 192) and the hollow fighting (132, 134, 194). The fighting (56, 132, 134, 194) also includes a forward, reverse pitch section (64, 162, 216). The extrusion screws (50, 52, 124, 126, 190) are designed to be used as complemental pairs as a part of twin screw processing devices (20), and are designed to impart high levels of thermal energy into materials being processed in the devices (20), without adding additional moisture.

A screw machine includes an inductive heating device for the processing of material to be processed. The inductive heating device is used to heat the material in a heating zone. In the heating zone, at least one housing portion is made of an electromagnetically transparent material at least partly, the material being non-magnetic and electrically non-conductive, whereas at least one treatment element shaft is made of an electrically conductive material at least partly. During the processing of the material, the inductive heating device generates an alternating magnetic field that produces eddy current losses in the at least one treatment element shaft, the eddy current losses leading to a temperature increase of the at least one treatment element shaft. The material is heated on the at least one heated treatment element shaft, in particular until it melts. The screw machine allows a simple and efficient melting of the material, with the result that a mechanical energy input and a resulting wear of the screw machine can be reduced significantly.

A twin-screw extruder is provided in which screws have different rotational speeds depending on the process of treating the raw material and in which degradation of the raw material is less likely to occur.

Twin-screw extruder 1 has two screws 3, 5 that extend in parallel to each other. Each screw 3, 5 has cylindrical upstream screw 31 and downstream screw 35, wherein upstream screw 31 has shaft hole 315 that extends in longitudinal direction X and screw flight 316 on an outer circumferential surface thereof, and downstream screw 35 includes large diameter portion 353 having screw flight 357 on an outer circumferential surface thereof and small diameter shaft portion 351 that has a smaller diameter than large diameter portion 353, wherein small diameter shaft portion 351 of downstream screw 35 is inserted into shaft hole 315 of upstream screw 31. Upstream screw 31 and downstream screw 35 can be independently rotated. Twin-screw extruder 1 further includes upstream rotating mechanism 84 that rotates upstream screws 31 of two screws 3, 5, and downstream rotating mechanism 83 that rotates downstream screws 35 of two screws 3, 5.

A system according to various embodiments can include a source for supplying a material to be treated, an extruder, at least two screws, and a drive coupled to the screws for axially rotating the screws. The extruder includes an inlet for receiving the material, which is fed therein in a controlled manner. The screws are provided within the housing of the extruder. The screws have a plurality of compression and release stages that create mechanical heat which is directly applied to the material to change the mechanical properties of the material thereby facilitating a conversion of a physical state of the material from a non-compactable state to a compactable state as the screws rotate and move the material longitudinally along the screws to produce a final product, for example, a feed tub for use as an animal feed.

A screw extruder with rollers includes a screw which extrudes a material; a casing which houses the screw and which is provided with a charging port for the material; and a pair of an upper roller and a lower roller which are arranged in front of the casing and mold the material extruded by the screw into a sheet, in which one of the upper roller and the lower roller has both end portions in an axial direction, and a main body portion between the both end portions, and a cross-section of the main body portion perpendicular to the axial direction has an oval shape.

A process for extruding plastic compositions is provided. The process comprises providing a multi-screw extruder with screw elements and conveying, kneading, mixing, degassing or compounding the plastic compositions in the multi-screw extruder using the screw elements.

A dry granulation process using a twin-screw extruder for granulating a powder mixture which includes at least one active ingredient and at least one carrier. The process includes steps of kneading the powder mixture in the screw barrel of the twin-screw extruder at a barrel temperature below a melting point of the at least one active ingredient and a melting point or a glass transition temperature of the at least one carrier to provide a kneaded powder mixture, and extruding the kneaded powder mixture to form granules. Granules and tablets produced using the dry granulation process in the twin-screw extruder are also provided.

The present invention relates to a masterbatch composition comprising high concentration of biological entities having a polymer-degrading activity and uses thereof for manufacturing biodegradable plastic articles.

A dry granulation process using a twin-screw extruder for granulating a powder mixture which includes at least one active ingredient and at least one carrier. The process includes steps of kneading the powder mixture in the screw barrel of the twin-screw extruder at a barrel temperature below a melting point of the at least one active ingredient and a melting point or a glass transition temperature of the at least one carrier to provide a kneaded powder mixture, and extruding the kneaded powder mixture to form granules. Granules and tablets produced using the dry granulation process in the twin-screw extruder are also provided.

A composite material sheet or panel is obtained by extruding a mixture composed of at least one thermoplastic material, particularly of the polyolefin family, and of mineral fibers having predetermined dimensional characteristics (diameter and length). The extrusion process is performed with parameters sufficient to generate in the sheet a three-dimensional structure embedded in the thermoplastic material.