A screw extruder for extruding a kneaded material, includes: a screw; and a casing housing the screw and having a material supply port on an upstream side. The screw has a shaft portion and a helical flight portion provided on an outer peripheral surface of the shaft portion. Regarding a clearance between a top portion of the flight portion and an inner wall surface of the casing, the clearance at a downstream side end of the flight portion is larger than the clearance at a downstream side end of the supply port. No area where the clearance decreases from the upstream side toward the downstream side is present between the downstream side end of the supply port and the downstream side end of the flight portion.

Methods, apparatuses, systems, and techniques relate to an extruder unit for producing preforms with a tube-like wall from a polymer melt and an associated extrusion process. The extruder unit has a receptacle for an exchangeable dispensing tool, it furthermore comprises at least two different and alternately usable profiling devices. These profiling devices have outlet-side fastening structures, which correspond in the various profiling devices and form the receptacle for the exchangeable dispensing tool, so that the profiling devices can be connected alternately to the same dispensing tool. In this way, any dispensing tool, depending on the wish of the customer, can be operated with different profiling devices, in particular, on the one hand, to carry out profiling by mandrel body movement or profiling by nozzle body movement.

Methods, apparatuses, systems, and techniques relate to a tube-forming device for an extruder unit or an extrusion device and a tube-forming process. The tube-forming device comprises at least one shaping sleeve, which is designed to shape a supplied stream of polymer melt from a substantially strand-like cross section into a tubular cross section. The shaping sleeve has a guiding passage embedded in the sleeve wall, such that the guiding passage is a cavity which lies within the sleeve wall and, in the radial direction of the shaping sleeve, is enclosed in a sealed manner with respect to the outer surfaces.

It is described an apparatus for the extrusion and mixing of plastic materials, for example rubber-based and silicone-based materials, comprising a dump extruder body whereon two conical screws (2) converging towards an extrusion die (3) suitable for being occluded by closing means (4) are mounted, the conical screws (2) being accommodated within a low-pressure compounding chamber (1) and within a pair of converging conical channels also defining a high-pressure chamber (2), said low-pressure chamber (1) corresponding to an upstream area with respect to an extrusion direction, wherein said high-pressure chamber (2) and/or said low-pressure chamber (1) accommodate a presser body (5, 5, 6), defining a movable wall suitable for causing a controlled change in the volume of the respective chamber (1, 2).

A feeding screw machine for feeding a processing screw machine comprises a housing with at least two housing bores formed therein and screw shafts rotatably arranged in the at least two housing bores. The at least two housing bores and the at least two screw shafts define a free volume in a respective cross-sectional plane, which decreases monotonically at least in some regions for continuous compression of a material in a conveying direction. This enables an improved supply of material with a low bulk density.

A plant for producing an extruded silicone intermediate has a mixer/extruder for mixing and subsequently extruding a silicone compound for producing a raw silicone extrudate. A heating apparatus of the plant serves for crosslinking the raw extrudate to give the crosslinked silicone intermediate. The result is a plant with which a silicone intermediate of this kind can be produced more economically.

A screw extruder which extrudes a kneaded material includes a screw having a helical flight provided on an outer peripheral surface of a shaft portion thereof, and a chamber housing the screw. In the screw extruder, a flight thickening portion is provided at a part which is a tip portion of the flight and is on the reverse side of a rotation direction of the flight.

A screw extruder which extrudes a kneaded material includes a screw having a helical flight provided on an outer peripheral surface of a shaft portion thereof, and a chamber housing the screw. In the screw extruder, a flight thickening portion is provided at a part which is a tip portion of the flight and is on the reverse side of a rotation direction of the flight.

A machine for applying hot-melt products having a structural body (1) provided longitudinally on the inside with a recess (2) extending between a supply inlet (3) for the product in solid state and a discharge outlet (4) through which the product exits in fluid state for its application, the recess (2) having a spindle (5) fitted with a helical blade (9) for conveying the product through a feeding zone, a melting zone and/or a compression zone, wherein the recess (2) has a conical zone (2.1) with a narrowing separating the feeding zone from the melting zone for compacting the hot-melt product, and on the inner periphery of the conical zone (2.1) having a plurality of indentations (8).

A machine for applying hot-melt products having a structural body (1) provided longitudinally on the inside with a recess (2) extending between a supply inlet (3) for the product in solid state and a discharge outlet (4) through which the product exits in fluid state for its application, the recess (2) having a spindle (5) fitted with a helical blade (9) for conveying the product through a feeding zone, a melting zone and/or a compression zone, wherein the recess (2) has a conical zone (2.1) with a narrowing separating the feeding zone from the melting zone for compacting the hot-melt product, and on the inner periphery of the conical zone (2.1) having a plurality of indentations (8).