| 摘要 |
<p>An extruder comprises a displacement part with a housing, inside of which at least one screw shaft is housed and which is provided, at one end, with a material entry opening for the material to be processed and, at the other end, with a material outlet opening for the processed material, and with an intermediate opening between the material entry opening and the material outlet opening for discharging gas from the displacement part. A material retaining device is connected to said intermediate opening and has at least one screw shaft inside an intermediate housing. This screw shaft extends from the intermediate opening to a gas discharge opening in the intermediate housing and conveys material entering the intermediate housing back into the displacement part. To this end, the screw section of the screw shaft facing the displacement part has a direction of thread that returns into the displacement part, and the screw section of the screw shaft facing away from the displacement part has an opposite direction of thread.</p> |
