Abstract: In a processing plant for producing plastics material granulate, the start-up takes place in such a way that a screw machine is firstly driven by means of a drive device and then plastics material to be processed is fed by means of a metering device into the screw machine. At least one conveying position of the plastics material in the screw machine is determined by means of a control device by evaluating at least one measuring signal. Depending on the conveying position determined, a granulating device is activated and put into operation. The method according to the invention allows a direct start-up of the processing plant without the use of a start-up valve. This ensures an easy and safe start-up of the processing plant.

Abstract: In a screw machine, to extend the material to be prepared with the latter, at least one processing element is configured as an extension-kneading element, the crest region of which has a reduced thickness compared to a flank region and, with adjacent processing elements, forms an extension channel for the material in the region between the triangles, which tapers in cross section in the flow direction of the material. Because of the tapering of the extension channel, the material is accelerated in the flow direction thereof and extended, so that high-molecular particles in the material are divided and the latter is therefore homogenized.

Abstract: In a processing plant for producing plastics material granulate, the start-up takes place in such a way that a screw machine is firstly driven by means of a drive device and then plastics material to be processed is fed by means of a metering device into the screw machine. At least one conveying position of the plastics material in the screw machine is determined by means of a control device by evaluating at least one measuring signal. Depending on the conveying position determined, a granulating device is activated and put into operation. The method according to the invention allows a direct start-up of the processing plant without the use of a start-up valve. This ensures an easy and safe start-up of the processing plant.

Abstract: A filter unit for an extruder system has an outer support body, which is hollow cylindrical and limits an interior. A plurality of outer through-openings open into the interior. An outer filter element is arranged on the support body in the region of the outer through-openings. An inner support body with a plurality of inner through-openings is arranged in the interior. An inner filter element is arranged on the inner support body in the region of the inner through-openings. Using the filter unit according to the invention, a low differential pressure of a plastics material melt to be filtered can be achieved as both the outer filter element and the inner filter element provide a corresponding filter area.

Abstract: In a screw machine, to extend the material to be prepared with the latter, at least one processing element is configured as an extension-kneading element, the crest region of which has a reduced thickness compared to a flank region and, with adjacent processing elements, forms an extension channel for the material in the region between the triangles, which tapers in cross section in the flow direction of the material. Because of the tapering of the extension channel, the material is accelerated in the flow direction thereof and extended, so that high-molecular particles in the material are divided and the latter is therefore homogenized.

Abstract: An extruder with a housing comprising parallel, partially inter-engaging bores and screws disposed therein is used when applying a method of feeding powdery bulk materials into such an extruder. A solid transport of powdery bulk material takes place in an inlet zone disposed downstream of a feed opening wherein said inlet zone is partially filled. The inlet zone is provided with at least one gas-permeable wall portion wherein a layer of bulk material is created on said wall portion, thereby preventing bulk material from passing through, The gas-permeable wall portion is connected to a vacuum source and to a pressure gas source. Furthermore, the gas-permeable wall portion has an inner wall which is set back with respect to the wall of the bores, thereby forming a gap with a partially annular cross section wherein a layer of the bulk material is formed in the gap.