Screw Conveyor Capacity & Motor Power Calculator (CEMA)
Determine CEMA volumetric conveying capacity, screw RPM, material friction horsepower ($HP_m$), and total drive motor power.
Screw Geometry & Conveying Route
Operating RPM & Motor Power Output
Recommended Tools & Equipment
Tested hardware and components for high reliability
CEMA Standard 350 Screw Conveyor Sizing
Screw conveyors utilize helical flights rotated inside U-shaped troughs to transport bulk solids. Sizing follows the Conveyor Equipment Manufacturers Association (CEMA) standard 350, where maximum cross-sectional trough loading is strictly restricted based on material abrasiveness:
• 15% Loading: Extremely abrasive, dense materials (clinker, iron ore, alumina).
• 30% Loading: Moderately abrasive granular products (sand, coal, sugar).
• 45% Loading: Free-flowing, non-abrasive light materials (flour, grain, sawdust).
Incline Derating & Fallback
When an auger conveyor operates on an incline, material cascades backward over the top of the rotating flighting into the preceding pocket. Capacity derates by roughly $2\%$ to $3\%$ per degree of incline up to $20^\circ$. Beyond $25^\circ$, tubular housings with short-pitch flights are required to avoid zero net forward conveying.