Screw conveyors, also known as auger conveyors or spiral conveying systems, are mechanical conveying devices that transport bulk goods or viscous materials using a rotating screw (spiral). They are among the oldest and most reliable conveying technologies in industry.
Operating Principle
A screw conveyor essentially consists of:
- a rotating shaft with a helical flight (screw),
- a tube or trough in which the screw rotates,
- a drive that sets the screw in rotation.
The rotational movement continuously pushes the material along the axis of the screw. Depending on the design, this can occur horizontally, inclined, or vertically.
Areas of Application
Screw conveyors are used wherever powdery, granular, or pasty materials need to be transported, metered, or mixed. Typical applications include:
- Agriculture (grain, animal feed)
- Food industry (flour, sugar, doughs)
- Construction industry (cement, sand)
- Recycling and waste management
- Plastics industry (granulates, pellets)
- Chemical industry (powders, reaction masses)
Advantages
- Closed transport: low dust & hygienic
- Robust and durable construction
- Very good dosing capability
- Versatile (horizontal, vertical, inclined)
- Suitable for abrasive and viscous materials
- Relatively easy to clean and maintain
Disadvantages
- Not ideal for sensitive or easily breakable materials
- Limited conveying lengths
- Higher wear with abrasive materials
Variants
- Trough screw conveyor (open, easy to clean)
- Tube screw conveyor (closed, dust-tight)
- Flexible screw conveyor (flexible shaft for confined spaces)
- Twin screw conveyor (for tough or adhesive materials)
- Dosing screw conveyors (precise material feeding)