ABSTRACT

Powder feeders play an important role in powder-handling processes, such as feeding raw materials or discharging product materials from a storage vessel. The feeders should be selected carefully, because some feeders might be unsuited to the process, resulting in failure to feed the material. Further, the dynamic characteristics of the feeders could also affect the accuracy of feeding. Variations in powder properties or operating conditions are also important factors that can cause feeding failures. A rotary feeder consists of a rotor, a rotor case, and a motor drive. The powder placed in a hopper flows into the rotor space by gravity, and is discharged through the exit after a half revolution. A screw feeder consists of a screw, a U-shaped trough or cylindrical casing, and a motor drive. The powder feed rate is adjusted by changing the belt speed or gate opening. Vibrating feeders use either electromagnetic or electromechanical drives.