Bucket conveyors (sometimes known as bucket elevators) are a proven way to move powders and other materials vertically. For any given application, selection of the proper type and size of conveyor depends upon throughput requirements and the characteristics of the material being conveyed.
The capacity (or more properly, capacity rate) of a bucket conveyor defines the quantity of material that the equipment will convey. Bucket conveyor capacity, or capacity rate, is synonymous with throughput rate. The capacity of any particular equipment design is usually a function of bucket size, number of buckets per foot, and the unit operating speed. Bucket conveyor capacity is usually expressed as the maximum throughput achievable, given a bucket fill percentage and unit operating speed.
For example, a TipTrakTM TT500 bucket conveyor has a stated capacity as follows:
Maximum throughput rate with 67% bucket fill @ 100 fpm: 4.5
This specification means that the TT500 unit can achieve a maximum throughput rate of 4.5 cubic feet per minute, with the buckets filled to 67% of capacity and the unit running at an operating speed of 100 feet per minute.
Why does the specification refer to a 67% bucket fill (approximately two-thirds of bucket capacity)? Simply because experience shows that filling the buckets beyond this point actually degrades throughput as a result of material loss due to spillage. Because a 67% bucket fill has proven optimal in practice, all TipTrakTM bucket conveyor capacities are based on this bucket fill requirement. The various capacities of the TipTrakTM line of bucket conveyors are shown below:
Choosing a bucket conveyor with a capacity that matches the needs of a particular application involves making an engineering calculation that considers the desired application throughput rate and the bulk density of the material to be moved. This calculation allows the equipment supplier to recommend the equipment model with the capacity that best meets the desired application throughput rate, given the material bulk density. At UniTrak, we routinely perform this calculation in the Application Review stage of our “customerization” process for determining the optimal equipment solution to supply for a customer application.
Variations in the calculated versus the actual capacity rate can sometimes arise from differences in material bulk density, the bucket fill rate, and the equipment operating speed. Good equipment suppliers consider these sources of variation when making their conveyor recommendations, thereby providing equipment operators with control over these issues, should they arise.
To find out more about our TipTrakTM line of bucket conveyors and how they can successfully service your application requirements, please contact our sales department directly.