Screw Conveyors for Material Handling

Screw conveyors help move materials that are being transferred to bins or other material handling locations. The rotation of the augers left or right determines the direction the materials will move.

Screw conveyors are the simplest and cheapest for transfer of materials at rates of up to 40 ton/hr over distances of up to 65 ft. Screw conveyors are flexible; depending on their diameter, they can be curved to some extent. Screw conveyors consist of a special heat-treated and tempered carbon or stainless steel spiral that rotates with an ultra-high-molecular-weight polyethylene (UHMWPE) food-grade tube. The transport of material in a screw conveyor occurs by the turning of a helix screw in a trough casing. The particles should be smaller than the screw pitch. The screws can have constant, variable, or tapered pitch. In tapered pitch, the distance between the grooves gradually decreases down the length of the conveyor.

Screws with round cross sections are flexible and strong, and screws with flat cross-sections are more suited for high velocity applications. The trough casing can be round, rectangular, or U-shaped. The picture below to the left shows a single helical screw conveyor, and the picture below to the right shows a dual auger design.

 

Usage Examples

Screw conveyors are used in pharmaceutical, food, and dairy production applications. The screw conveyor below to the left is used in an asphalt plant, and the one to the right is used as a feed for a metal turnings shredder.

 

Advantages

 

  • Closed tube prevents product contamination
  • Inexpensive to purchase and operate
  • Quick installation
  • Flexible conveyors can be routed around obstacles
  • Product handled gently
  • Product is usually very accurate and highly repeatable batches are possible
  • Conveyor can be easily emptied at the end of a batch operation
 

Disadvantages

 

  • Particles must be smaller than the pitch
  • Abrasive materials will most likely cause wear
  • Small scale experiments needed to determine operating parameters
  • Need to run full of products

Need a quote? Provide the answers below: What is being conveyed? How far? How much? How fast? What Angle? How is it fed?