Screw extruder with a device for influencing the yield

摘要

The pellet ejector (16) axially downstream from the press screw (6) has two single nozzles (20) whose summated passage sections equal the total passage section required for the volume of dry substances per unit time. Four nozzles are preferred arranged symmetric to the screw axis (15), the degree of extraction being increased by increasing the number of nozzles (20) for any one and same substance whilst retaining the total passage section available to it. In operation, screw (6) conveys the funnelled (2) material e.g. oil seed, to the press head (4) (9) via constant screw turns (10) and surround housing (1) where the material is deflected towards the screw axis and through the gap between convex screw end (13) and concave inner face (14) of the housing for partial oil extraction prior to the final pellet stage where the remaining pellet (18) material is intensively pressed before departing through the nozzles. Recovered oil flows back (19) to the housing oil outlets (12).