COMPRESSION SCREW WITH COMBINATION SINGLE AND DOUBLE FLIGHTS

摘要

A screw for a compression dewatering device comprising an elongatedshaft having axially spaced apart first and second ends, a conveying sectionat the first end of the shaft, having a single helical screw flight rigidlyprojecting from the shaft, a flightless transition section axially adjacenttheconveying section, and a dewatering section axially adjacent the transitionsection, having a double helical screw flight rigidly projecting from theshaft.Another embodiment is a compression screw having a perforated tubulardewatering wall intermediate the ends, followed by an imperforate spool wallat the discharge end. The screw includes a central shaft, a conveying sectionextending axially from the inlet end of the shaft, having a single helicalscrewflight rigidly projecting from the shaft, a flightless plug section extendingaxiallyfrom the discharge end of the shaft, within the spool wall, and a dewateringsection adjacent the plug section, having a double helical screw flightrigidlyprojecting from the shaft. A flightless transition section is situated betweenthe conveying section and the dewatering section. A gravity feed device isoperatively associated with the inlet end for depositing bulk solids materialthrough the feed opening onto the conveying screw, and a drive system isoperatively connected to the inlet end of the screw for rotating the screw inthehousing.