High capacity degassing and aerating - involves spreading melt into thin film over large area formed by shafts with planetary rotation around central shaft

摘要

In a process for degassing and aerating thermoplastic melt, the liq. melt is fed continuously to a degassing and aerating extruder. The melt is then spread out into a thin layer over a large surface area. While passing through the thin layer zone the melt is subjected to vacuum to remove air and volatiles. The process extruder comprises a housing (1) containing several axially parallel thin film shafts (3) which all rotate in the same direction. Each shaft (3) profile allows intermeshing with the adjacent shaft (3) to form thin film melt between them. At one or both ends of each thin film shafts (3) planetary wheels (40) are formed which are driven by a central toothed shaft (5, 5a) linked to a main drive. The middle section (2) of the central shaft is smooth and cylindrical. All thin film shafts (3) rotate about their own axis and around the smooth central shaft (2). Thin film shaft (3) design allows rolling on the smooth faces of both the central shaft (2) and inner housing wall. A degassing vent (12) is provided in the housing (1) wall. USE/ADVANTAGE - For degassing thermoplastic polymer melts. Dead spots in the extruder are eliminated, which prevents thermally degraded polymer deposits.