A screw feeder is a positive-displacement device. Not only can it move solid particles from a low-pressure zone to a pressure zone with a pressure seal; it can also measure the amount of fuel fed into the bed. By varying the speed of its drive, a screw feeder can easily control the feed rate. As with a gravity chute, the fuel coming out of a screw does not have any means for dispersion. An air dispersion jet employed under the screw feeder can serve this purpose.

A mechanism for handling bulk solids materials where a helix or screw turns inside a hopper moving the materials forward and out of the feeding device into a process.

Raman Systems carries a full line of industrial, sanitary, volumetric or gravimetric screw feeders for most material handling applications. The feeders can be configured for either continuous or batching operations where materials such as pellets, powders, cohesive or adhesive types need to be fed. Single screw and twin-screw models are also available.