Full definition
The rubber layer on the carrying side (upper surface) of a conveyor belt that directly contacts the transported material and protects the underlying textile or steel cord carcass from abrasion, impact, heat, oil, and environmental damage. Cover thickness: 2-10 mm typical for top, 1.5-4 mm for bottom (pulley side). The formulation is selected based on material characteristics and environment — grades per ISO 14890: H/D/L for abrasion resistance, T1-T4 for heat resistance, MOR/MORV for oil resistance, and fire-resistant grades per ISO 340. Standard compound: NR or NR/SBR blend, 40-65 Shore A. Cover quality is designated as: top cover thickness × bottom cover thickness (e.g., 6+2 means 6 mm top, 2 mm bottom). The top cover acts as a sacrificial wear layer — when worn to 1-2 mm above the carcass, the belt should be replaced or covers re-topped. Cover-to-carcass adhesion is critical: minimum 3.5 N/mm per ISO 252. Per DIN 22102 and ISO 14890.