| Apron Feeder | ||
| Apron feeders consist of two strands of tractor- type chain fitted with cast of fabricated pans. The chain is supported on standard tractor-type carrying rollers and plain rollers at the feeder’s return side. The equipment design is based on continuous operations, built to withstand high-impact loads and therefore suitable for coarse and abrasive materials, such as limestone, hard rock, iron ore, copper ore, and over-burden, among others. Krupp Materials Handling has engineered apron feeders with pan widths ranging from 800mm to 3,400mm, lengths as great as 30m, and capacities of up to 12,000tph. Special designs allow inclinations of up to 28° from the horizontal. The drive system features fixed or variable speeds, with either a low-speed high-torque or high-speed low-torque hydraulic motor combined with planetary reducers or electro-mechanical drive units. | ||
| Main Frame | ||
| The main frame of rigid and robust welded steel fabrication is suitably stiffened to withstand maximum loading conditions likely to be generated during start-up, under the specified operating conditions and during filling of the hopper. The structure provides support for all mechanical components and comprises of two longitudinal beam and cross members, fabricated from hot rolled standard sections. All structural joints are designed and fabricated to applicable SABS standards. The frame incorporates impact rails to minimise deflection of the feeder pans during loading conditions and provides adequate support over the entire carrying side of the apron feeder. Permanent lifting lugs are welded to the frame and are designed to lift the fully assembled feeder. | ||
| Carrying Rollers | ||
| The carry rollers are standard single flange track rollers, sealed and lubricated for life with hardened and ground shafts. The rollers are mounted on support frames which permits easy removal for maintenance. The rollers are closely spaced to provide suitable support for the chain. | ||
| Return Rollers | ||
| The return rollers are designed with grease lubricated bearings and spaced to provide suitable support for the return chain/pan assembly. The rollers are flange mounted onto the frame girderweb, allowing easy removal for maintenance and replacement. | ||
| Sprockets | ||
| The chain sprockets are standard design and feature an odd numbered hunting tooth design to evenly distribute work load and wear. The bolt on sprocket segments are deep hardened to provide long wear life and are capable of being reversed to utilise the wear life. | ||
| Pans | ||
| The apron feeder pans of cast design integrated high side skirts and heavy-duty stiffners with machined sliding pads. The pans are of over-lapping “leak proof” design with minimum gaps between each pan. The chain is fastened either inside of the pan or to the outer edge. This arrangement provides easy access to the chain bolts all times. | ||
| Drive Shafts | ||
| The precision machined drive shaft will be designed in accordance with SABS standard for such items. Two hubs, fully machined, will be clamped by locking assemblies onto the shaft. Segmented sprockets are bolted onto the hub. The shaft wil be supported in two spherical roller bearings mounted into a heavy split bearing housing. The bearings will be fitted with grease purged taconite seals. Jacking screws are provided for easy housing alignment. | ||
| Take-up Beam | ||
| The design incorporates a welded beam design instead of a common shaft design. The unit consists of a full welded beam assembly, fitted with two standard Caterpillar idlers. The take-up beams are bolted onto the main frame and chain tension can be controlled simply by inserting and removing shims. The beam adjustment is supported by hydraulic cylinders. | ||
| Chain Tension | ||
| The chain tension device incorporates an hydraulic jack acting against the sliding take-up beam. The take-up beam is locked into position by means of bolts and shims. The hydraulic jack will be activated by an on-board, manually operated pump. | ||