A series of independent screw feeders can be used to unload a large collecting tank or silo. This arrangement allows for varied material rates to be pulled from different storage areas and improved reliability as one unit can be isolated for inspection/maintenance without shutting down the rest of the system.
Screw feeders are set up to be flood fed, so that regardless of the amount of material in a hopper above the inlet the output rate will remain constant. It is this trait that makes screw feeders a critical part of a system, as they set the rate of material flow for the rest of the equipment downstream.
Depending on the product being conveyed and the inlet size, different types of flighting are used in screw feeders. Some options include tapered flights, variable pitch flights and cone mounted flights.