Conveying Screw Elements for Twin Screw Extruders

Single flight conveying elements provide higher conveying efficiency than standard double flight elements. Their wider flight design reduces leakage flow and increases pressure-building capability.

Best suited for:

• Feeding sections

• Extrusion zones

• Applications requiring strong conveying force

Double flight conveying elements are the most widely used design in twin screw compounding. They provide the best balance between free volume and torque transmission.

Best suited for:

• Feeding sections

• Venting zones

• Pressure control sections

Triple flight elements provide strong distributive mixing with lower shear. They are commonly used in melt mixing sections where gentle material distribution is required.

Best suited for:

• Melt distribution

• Sensitive materials

• Low-shear compounding

Transition elements are designed to connect different screw element geometries while minimizing dead zones and material retention.

Best suited for:

• Transition between single and double flight elements

• Connection between SK and standard conveying elements

• Geometry change zones within complex screw configurations

Stretching elements, also called S-type elements, improve material exchange and distributive mixing in partially melted zones.

Best suited for:

• Semi-plasticized material zones

• Improved dispersion

• Gentle mixing processes

SK conveying elements provide approximately 15% higher free volume than standard conveying elements and are particularly suitable for low bulk density materials.

Best suited for:

• Feeding zones

• Side feeding

• Low bulk density materials

SSK conveying elements combine the strong conveying ability of single flight elements with increased free volume.

Best suited for:

• Difficult-to-feed materials

• Low-density powders and fillers