Screw conveyors are one of the oldest conveying methods known to man and still the ideal method for many applications. Though screw conveyors and augers are technically synonymous (any conveyance method driven by rotating threads) the processing industry typically reserves the term “screw conveyor” for larger executions. (See augers on ABMBrewery.com, and see screw feeders here.)
Screw conveyors are used for a huge array of products as long as they’re not too abrasive, fragile, stringy, or are solid and sticky. They’re highly popular in chemical, meat, agriculture (excluding produce), plastics, waste, and many other industries. Their simple & rugged design makes them cost-effective, versatile, and able to accommodate numerous inlets and outlets or act as a live bottom to a bin.
High-grade and polished surfaces can be used to reduce it, but friction is inherent in screw conveyor design. For this reason they’re not to be used with delicate or extremely abrasive materials, such as aggregates, which can eat through any metal over time.
Open troughs are ideal for bulk applications where product needs to be fed over a large area and conveyed to a single point. Examples include front loaders dumping grain into the beginning of a process, live bottom bins for large vessels, etc.
Closed troughs are necessary for many application whether it be to keep environmental elements from getting in, product from getting out, or to meet hazard or sanitary specifications. And of course, closed trough means the product can be conveyed up steep slopes or vertically.
Shafted screw conveyors are more reliable up steep slopes for many applications and are much sturdier. They can go greater lengths, can convey tougher product, and because they’re not constantly rubbing on the liner or bin of the conveyor, they require less maintenance.
Shaftless screw conveyors are especially effective with uneven, clumpy, and sticky material. This advantage with such product remains for vertical runs because they don’t need a bottom shaft. And because they don’t have a core, their capacity is increased and they can go about corners.
Augers: Generally the term “auger” is reserved for lower-throughput, enclosed designs.
Screw Feeders: Screw feeders, or meter screws, are screw conveyors meant to convey precisely. This will include extra sensors and special drives & screws.
Advantages of Screw Conveyors
Controlled flow allows metering
Compatible with any orientation, horizontal to vertical
Wide range of products, from powders to liquids
Can be made vapor-tight for hazardous products in chemical industries
Can easily have multiple discharges
Drawbacks of Screw Conveyors
Can destroy delicate product
Can be destroyed by tough product
Not great for stringy material