COMPRESSION SCREW WITH COMBINATION SINGLE AND DOUBLE FLIGHTS

摘要

A screw for a compression dewatering device comprising an elongated shaft having axially spaced apart first and second ends, a conveying section at the first end of the shaft, having a single helical screw flight rigidly projecting from the shaft, a flightless transition section axially adjacent the conveying section, and a dewatering section axially adjacent the transition section, having a double helical screw flight rigidly projecting from the shaft. Another embodiment is a compression screw having a perforated tubular dewatering wall intermediate the ends, followed by an imperforate spool wall at the discharge end. The screw includes a central shaft, a conveying section extending axially from the inlet end of the shaft, having a single helical screw flight rigidly projecting from the shaft, a flightless plug section extending axially from the discharge end of the shaft, within the spool wall, and a dewatering section adjacent the plug section, having a double helical screw flight rigidly projecting from the shaft. A flightless transition section is situated between the conveying section and the dewatering section. A gravity feed device is operatively associated with the inlet end for depositing bulk solids material through the feed opening onto the conveying screw, and a drive system is operatively connected to the inlet end of the screw for rotating the screw in the housing.