DIN 22252:2012-07

In underground mining, coal occurs during loosening (with shearer loaders, amongst others) as lumpy debris mixed with rock with individual pieces of very different sizes and hardness. For transport from these cramped areas characterized by continuous advancement of the conveyor, heavy chain conveyors are used due to the necessary robustness where the debris is transported by revolving chains with flightbars in conveyor channels. Due to the continuously increasing capacity the required operating power shall be initiated by several electric drives and various chain arrangements (single strand or double medium-chain conveyors) shall be used. In particular the round steel link chain is highly stressed due to friction, tensile forces and hinge requirements interacting with the chain wheel and chain connectors. Chain failure causes immense costs for the procurement, transport and installation of spare parts in high-performance plants. The standard applies to round steel link chains used as means of traction in chain conveyors, bucket elevators and winning equipment, primarily in mining, in particular in face conveying as short chains strands with shackle type connectors in accordance with DIN 22253 and scraper bars in accordance with DIN 22257. The standard specifies requirements regarding the design, selection of materials, test methods and operating forces. The round steel link chains according to this standard shall not be used as load handling devices, slings or hoist mediums in the context of DIN 15003. The standard has been prepared by NA 008-05-05 AA "Einzelteile für Förderer" ("Components of conveyors") of FABERG.