Frequently Asked Questions - Screw Conveyors and Feeders

Exploded Assembly View of a Typical Screw Conveyor

FAQs:

Screw conveyors are typically used for free-flowing materials, like grains, powders or pellets.  They can be designed to handle much harder to convey materials, such as those that include lumps, materials that are sticky or bridge up, aerate and become fluidized, or generally sluggishly-flowing materials.  They can also be adapted to handle very abrasive materials with heavier components and abrasion-resistant construction such as weld-on hard surfacing on the screws, screws and troughs made of abrasion-resistant steel, or both.

A screw conveyor is fed material at a constant rate by something else.  That can be as simple as a slide gate that is throttled open on a grain application, but for most industrial applications it means that the conveyor is fed a constant amount of material by a rotary airlock or feeding device of some kind.  A conveyor simply moves material, nothing more.

A screw feeder is flooded with material at the inlet.  As the screw turns, it dispenses a metered volume of material every revolution.  Controlling the speed of the screw will increase or decrease the volume of material dispensed by the feeder.  Screw feeders require more horsepower to shear material against itself out from under the hopper since they often perform the job of both metering device and conveyor.

Conveyors and feeders are sized according to the volume and density of the material they have to handle.  This is usually denoted by X lbs/tons per hour of material of Y density in lbs per cubic foot. If you are moving the common materials (or materials very similar to them) listed for the pre-engineered models, you can select the model of conveyor that meets your volume/tons per hour requirements, the length required, and any other options you may require.  If you don't see what you need, please contact SBE for a screw conveyor or feeder designed specifically for your application.