ABSTRACT

The screw conveyor is one of the oldest and most versatile conveyors in use today. Screw conveyors can perform the following operations: cooling and heating; mixing; de-watering; compaction or aeration; and particle size reduction. Screw conveyors must be fed material at a controlled uniform rate. This may be from an upstream process, feeder, or conveyor. Materials can also be heated or cooled in a screw conveyor using a jacketed trough and/or a hollow flight with a heat transfer fluid flowing through it. The two types most commonly used in screw conveyors are hanger bearings and flange bearings. A feeder is designed to control the rate of flow of a material from a bin or hopper. It is usually designed in conjunction with the bin or hopper it will service. This chapter deals with the feeder screw; the design of a bin or hopper is a science in itself.