Bucket elevators play an important equipment role in bulk material conveying technology wherever vertical conveying is involved. Over more than 30 years, Aumund has continuously refined its bucket elevator technology and offers strong and capable solutions worldwide for the vertical transport of bulk material. The standards forged by Aumund have been proven in practice a thousand times over. Aumund belt bucket elevators are characterised by large conveying heights of up to 200 m and conveying capacities of up to 2500 tph. The AUMUND Belt Bucket Elevator BWG-GK for coarse material makes the transport of material with sizes of up to 80 mm possible.
Figure 1. AUMUND Belt Bucket Elevator type BWG-GK for coarse material: the narrow, overlapping bucket configuration permits the belt to disappear entirely behind the buckets. No coarse material will be thrown behind the backs of the buckets, even after stoppage.
The main task during development of a belt bucket elevator for coarse material is protecting the belt from damage caused by the conveyed material. Aumund therefore follows a new path: the narrow, overlapping bucket configuration permits the belt to disappear entirely behind the buckets. It is thereby protected and no coarse material can become jammed between the backs of the buckets and the belt. The outer edges of the belt are simultaneously protected. Even in the case of a stoppage with filled buckets, no coarse material will be thrown behind the backs of the buckets (Figure 1).
Another task is to ensure a safe bucket attachment and, considering the loading conditions of the buckets, even in case of scooping. Here, the design of the Aumund steel cord belt with transversal steel cord reinforcement provides high pull-out strength and a reliable fixing for the bucket fastening. These plate screws can be used exclusively for fitting the buckets (Figure 2).
The plate screws developed by Aumund differ significantly from conventional DIN plate screws and have been designed for a longer belt service life and higher carrying capacity. Therefore, further attachments to increase the clamping force at the bucket fastening are not necessary. The advantage: the belt runs smoothly and without high abrasion on the drive pulley. Only small dead loads have to be transported.
Figure 2. The AUMUND belt design for reliable bucket attachment.
Furthermore, the belt of a bucket elevator needs to provide a high tensile strength, a low net weight and a low elongation, in addition to good alignment. This is achieved by a specialised production process and, above all, by a high transversal rigidity. The bucket elevator belt has to be optimally designed for its attachments like buckets, rubber seals and endless splices in order to function as a reliable complete system in daily operation, even after many years. All this is ensured by the carcass construction of the Aumund bucket elevator belts in combination with the Aumund bucket fastening system. Closely spaced high-tensile steel cords act as continuous tensile members. This allows belt strengths up to 4200 N/mm for lift heights of more than 200 m. On the front side as well as on the back side of the tensile members steel cord transverse reinforcements strengthen the belt. In contrast to reinforcements with textile fabric inlays, the advantage of steel cord transverse reinforcements is the higher adhesion of the rubber. This higher adhesion ensures a permanent connection of the individual belt layers, even under the influence of temperature.
Newly developed rubber compounds based on ethylene propylene diene monomer (EPDM) allow operational ranges up to a material temperature of 150°C for AUMUND Belt Bucket Elevators. Even peak temperatures up to 170°C may be reached. Load tests under industrial daily routines proved that EPDM-belts are much more resistant to ageing than belts made of styrene-butadiene rubber (SBR).
Adapted from press release by Louise Fordham
Read the article online at: https://www.worldcement.com/product-news/11032015/aumund-belt-bucket-elevator-for-material-sizes-up-to-80-mm-175/