Abstract: The invention relates to a method for manufacturing a foaming synthetic material, for example, polystyrol, by means of an extruder, in whose entry the synthetic material is fed, to which by means of a fumigation aperture foaming gas in a liquid form, for example pentane, is introduced at a pressure maintaining the foaming gas in its liquid form, whereby throughout a following extruder region, the synthetic material provided with the foaming gas is homogenecised.

Abstract: A plastifying extruder of the double-screw type, to avoid dead zones in the flow, has at its throttle location throttle disks on the screws formed with outwardly open recesses angularly equispaced on the disks. Pins distributed around the screws in the throttle region project radially into gaps between the disks and can penetrate to a greater or lesser extent into these gaps to provide a variable flow cross section.

Abstract: A double worm extruder for kneading units along the worms which are rotatable in the same sense. Each kneading unit has three or more circumferentially offset polygonal disks which have sealing surfaces at diametrically opposite locations closely juxtaposed with the inner wall of the housing. These sealing disks are flanked by edges which are inclined to the axes of the worms so as to insure greater flow cross sections past the disks and thereby avoid shear peaks in the extruded material and thermal decomposition thereof.

Abstract: Process and device for drawing off and blocking off a melt, especially of plastic material, with a heatable melter (1) fitted with a blocking valve (3) acting as a melt distributor from which the melt flows into a nozzle plate (10) which divides the melt by means of nozzles (14) into a plurality of threads, whereby the temperature of the melter and nozzle plate is regulated separately and the blocking valve is closed to block the melt off and the nozzle plate is tightly closed off by a cover (18). To draw off the melt with the blocking valve open, the temperature of the melter and the nozzle plate is kept substantially at the same level and to block off the melt with the blocking valve closed the nozzle plate is taken to a temperature just above the solidification temperature of the melt material.

Abstract: A plastifier extruder of the double-screw type has a slide plate shiftable toward and away from the screws at an acute angle to the axes thereof in a chamber having a trapezoidal axial cross section between extreme positions in which a surface of the plate parallel to the axes lies along one long side of the trapezoid and another limiting position in which the surface lies along the other long side of the trapezoid.

Abstract: A device for cooling, drying, and granulating molten strands issuing from nozzles with an outlet channel, the upper end of which is located below the nozzles, a device, generating a current of cooling liquid over the outlet channel, a granulator arranged downstream of the outlet channel and with a dehydrating section that is arranged upstream of the granulator and in which the strands rest on a support provided with orifices for the unrestricted passage of the cooling liquid. The outlet channel in the region following the dehydrating section is provided with inlet nozzles that inject a current of fluid and that are so close together and arranged over such a length in its bottom that the strands are guided with respect to the bottom virtually without friction along the outlet channel in the granulator arranged at its lower end and with a degree of dehydration that enables immediate further processing.

Abstract: An apparatus to cool and granulate strands discharged in a molten state from nozzles, particularly strands formed of plastics materials, includes a feeder trough having at its receiving end a collecting region disposed below the nozzles and a granulator at the opposite end thereof. The feeder trough includes over its entire length, a collecting region and a transport region, a longitudinally grooved perforated plate or screen material in which only a single strand is conducted along each groove, the strands being borne and guided along the grooves of the feeder trough by a gas current that passes through the plate material, aided by longitudinally directed gas current that may be blown along the grooves from a source disposed at the receiving end of the trough ahead of the collecting region.