Capacity (\( C \)):

\[ C = \frac{(D^2 - d^2) \cdot P \cdot N}{36.6} \]

Where:

• \( C \) is the capacity of the screw conveyor, in cubic feet per hour (ft³/hr).
• \( D \) is the screw diameter, in inches (in).
• \( d \) is the shaft diameter, in inches (in).
• \( P \) is the screw pitch, in inches (in), normally equal to \( D \).
• \( N \) is the shaft speed, in revolutions per minute (rpm).