Inclined and Vertical Screw Conveyors – Design Considerations Guide

CEMA Inclined and Vertical Screw Conveyors – Design Considerations Guide

CEMA Guide No. 355 (2021)

This CEMA Design Considerations Guide provides practical engineering guidance for the selection, design, and application of inclined and vertical screw conveyors used in bulk material handling systems.

Developed by the CEMA Screw Conveyor Committee, this guide expands on ANSI/CEMA Standard No. 350 by consolidating key considerations for conveying materials on an incline or vertically—applications where performance can vary significantly based on material characteristics and system design.

The document explains how increasing incline affects capacity, efficiency, and horsepower requirements, and outlines design strategies to improve performance, including modified pitch configurations, speed adjustments, clearance optimization, and elimination of intermediate hangers. It also compares U-trough versus tubular housings and discusses proper drive placement and sealing considerations for inclined systems.

For vertical screw conveyors, the guide covers material suitability, intake configurations (gravity, straight, and offset), speed requirements, capacity considerations, and discharge arrangements, along with practical insights into bearing selection, sealing, and operational limitations such as batch processing and material fallback.

Illustrations and diagrams throughout the guide—such as the capacity vs. incline chart  and pitch and configuration diagrams—help engineers visualize performance impacts and design tradeoffs.

• Document Type: Design Guide
• Document Number: CEMA Guide No. 355
• Committee: Screw Conveyor Committee
• Intended Audience: Engineers, designers, system integrators
• Applies To: Inclined and vertical screw conveyors for bulk material handling
• Approval Date: October 11, 2021
• Length: 13 pages