Abstract: A degassification device for a screw extruder which processes plastic material in which the extruder has a hollow housing and an extruder screw rotatable in the housing, the degassification device having a pair of degassification screws disposed adjacent to the extruder screw for rotation about axes parallel to the axes of rotation of the extruder screw. A housing headpiece accommodates the degassification screws and is in communication with the extruder housing such that gas and vapor produced in the extruder housing can flow radially therefrom into the housing headpiece for discharge therefrom. The degassification screws have threads which interengage one another and they are driven in the same direction of rotation. The housing headpiece has adjacent longitudinal bores which overlap one another and respectively receive the degassification screws therein with their threads interengaged with one another.

Abstract: A process for preparing highly viscous polyhexamethyleneadipamide by postpolycondensing the melt of a polymer having a relative viscosity of 2.5-2.7 (measured in a 1% strength solution in 96% strength sulfuric acid) in a twin-screw extruder having degassing zones and closely meshing screws which turn in the same direction. The polymer melt is polycondensed in the extruder by treatment in a plurality of serially arranged zones of alternatingly elevated and reduced pressure, wherein in the zones of elevated pressure, steam superheated to the temperature of the melt is supplied to the melt in an amount of 0.05-0.7 kg/kg of polymer, whereas in the zones of reduced pressure, the input vapor phase and water of condensation are drawn off. The temperature of the melt is raised at a uniform rate over the length of the extruder from 260.degree.-280.degree. C. in the first zone to 280.degree.-310.degree. C. in the last zone.

Abstract: A pump for viscous substances is constructed in such a way that it is constructionally simple and insensitive to foreign bodies. For this purpose, a plurality of shafts which are rotated in the same direction are arranged in a casing. Disks are fitted to the shafts and these disks are substantially clearance-free with respect to the corresponding wall portion of a recess and an adjacent shaft. At least one such disk and at least one adjacent shaft and the associated wall portion of a recess define a chamber. A plurality of such chambers are arranged in series and are interconnected by in each case an overflow duct.

Abstract: A screw extruder for continuously processing and degasing elastomers and polymers having a viscosity of more than 1,000 poise comprising a casing with an input zone at one end and a discharge zone at the other, several degasing zones within the casing along the length thereof and a pressure zone upstream of each degasing zone. The inside wall portions juxtaposed to the degasing zones include spiral grooves having at the most the same depth as the flights of the extruder screws.