The screw conveyor is one of the oldest methods of conveying materials known to mankind with the original design dating back to more than two thousand years. Today, modern technology has made the screw conveyor one of the most efficient and economical methods of moving bulk material. A U-trough screw conveyor is a widely used mechanical conveying system for handling bulk materials. It consists of a screw (helix) rotating within a U-shaped trough or housing. Below are the essential technical details, components, design considerations, and applications of a U-trough screw conveyor:

Components of a U-Trough Screw Conveyor

Trough

• Shape: U-shaped
• Material: Carbon steel, stainless steel, or abrasion-resistant steel
• Covers: Removable or hinged for maintenance and inspection

Screw (Helix)

• Types: Continuous, sectional, cut-and-folded, ribbon
• Material: Carbon/stainless steel
• Diameter: Typically ranges from 100 mm to 600 mm+

Shaft

• Supports the screw flighting
• Connected to the drive at one end and usually supported by a tail bearing at the other

Hanger Bearings

• Support the screw at intermediate points to prevent sagging in longer conveyors
• Types: Bronze, nylon, hard iron, etc.

Drive Unit

• Motor + gearbox
• Direct or chain drive
• Usually located at discharge or inlet end

End Bearings

• Located at both ends of the screw shaft

Inlet and Discharge Openings

• Configurable based on applications
• Can include slide gates or valves

Design Specifications:

Parameter	Description/Typical Values
Screw diameter	100 mm to 600 mm+
Pitch	Equal to or less than the diameter (standard pitch = 1D)
Trough length	Custom; typically up to 30 m with hangers
Trough material	Mild steel, SS304, SS316, abrasion-resistant steel
Trough cover	Bolted, gasketed, or quick-release
Angle of inclination	Horizontal to 45° (efficiency drops above 20°)
Capacity	Depends on pitch, diameter, speed, and fill level
Filling efficiency	30-45% (horizontal), drops with inclination
Rotational speed	Typically 30–100 RPM (lower for inclined/abrasive materials)

 

 Advantages

• Simple construction
• Economical
• Easy to install and maintain
• Good for dust-tight applications (with covers)

Limitations

• Not ideal for fragile materials (may cause degradation)
• Abrasive materials wear the screw and trough
• Requires hangers in longer lengths (which can cause material buildup)

Applications

• Agriculture: Grain, feed, flour
• Food processing: Sugar, salt, powdered milk
• Chemicals: Powdered chemicals, resins
• Mining: Sand, cement, minerals
• Wastewater treatment: Sludge handling

If you want a CAD drawing, design calculation sheet, or help with sizing for a specific material (e.g., sand, grain, fly ash), let us know the material properties, throughput (TPH), and conveying length/inclination, and Air Dynamics will provide tailored info.