Full definition
The primary power-transmitting cylinder in a belt conveyor system, located at the discharge (head) end, where the motor/gearbox assembly drives the conveyor belt by friction between the drum surface and the belt inner surface. Typical diameters range from 300 mm (light duty) to 1,500+ mm (heavy mining). Rubber lagging is applied to the drum surface to increase the friction coefficient from ~0.25 (bare steel) to 0.35-0.40 (rubber, smooth or diamond-grooved) or 0.40-0.45 (ceramic tile lagging). Diamond-pattern grooves channel water and fines away from the contact zone, critical in wet conditions. Lagging thickness: 6-12 mm rubber, 10-15 mm ceramic. Face width: belt width + 50-100 mm. Drum shell thickness calculated per DIN 22101 or CEMA for belt tension and bending loads. Crown: 0.5-1% of face width to center the belt. Brands: Rulmeca, Lorbrand, Van Gorp, Precision Castparts. Shaft sized for combined bending and torsion with deflection limits per CEMA.