Using a Bucket Conveyor to Convey Mixes and Blends

When conveying mixes and blends, the major challenge is to move the material without any separation or loss of consistency in the ingredients which make up the mix. Should ingredient separation or loss of consistency occurs when a mix is transported through a conveyor, product quality is degraded, leading to increased costs associated with scrap, rework, or customer complaints.
    
Maintaining blend consistency and uniformity is a major challenge for food processors, plastics resins manufacturers, chemical producers, and indeed any processing situation where the proportions and consistency of mixed ingredients must be maintained and assured through all stages of production.
    
In processes that involve mixes and blends, conveyors are often employed to move product from mixers and blenders to downstream processes. It is at this critical stage of production that degradation of blend uniformity and consistency can occur.
    
Advances in mixing technology have led to more thorough and gentle mixing, which results in blends of superior consistency and uniformity. Employing conveyors that are not up to the task of maintaining blend quality during handling can defeat the gains achieved with the latest generation mixing technology.
    
Equipment solutions for the task of conveying mixes and blends include pneumatic conveying and mechanical conveyors, such as flexible screws, aeromechanicals, tubular drag, and bucket conveyors. Each of these equipment choices has its pros and cons in terms of being able to convey mixes without any degradation in blend uniformity and consistency.
    
Of the more traditional equipment solutions, a bucket conveyor is the preferred equipment choice for successfully conveying mixes and blends. The basic operating principle of a bucket conveyor – that what goes in is what comes out – assures that mixes and blends can be transported without any loss of product integrity.
    
As a mix or blend is fed into a bucket conveyor, the material will settle somewhat in the buckets as the product moves through the conveyor. However, the ratios of the constituent ingredients will be preserved. When the product is discharged, blend integrity is assured since the ingredient ratios have been maintained during transport.
    
In contrast, with pneumatic, flexible screw, aeromechanical, and tubular drag conveyors, the ratios of mixed ingredients may not be maintained during transport. This is due to the way that these conveying technologies interact with the differing densities of the ingredients making up the mix. For example, with pneumatic conveyors, blend ingredients with differing densities may enter and move through the conveyor at different rates, resulting in a degraded mix being discharged. As noted above, this degradation in product quality increases production costs and diminishes customer satisfaction.
    
A further advantage of bucket conveyors is that, unlike dilute phase pneumatic or other mechanical conveyors, they will not aerate a mix or blend. This advantage can be important when the mix or blend is comprised of ingredients that may tend to fluidize when conveyed.
    
Mixes and blends are found in continuous and batch-type processes. Bucket conveyors are readily adaptable to support either type of process. For batch-type processes, smaller bucket conveyors which are readily mobile are available to support these types of operations. In addition, to support higher product variety which batch-type processing usually entails, these right-sized bucket conveyors can be fitted with Clean-In-Place systems to enable rapid equipment washdown and turnaround between product runs.
    
In summary, while successfully conveying mixes and blends can be challenging, bucket conveyors can offer a proven and reliable solution for handling these types of products.
    
James Bransfield is the Engineering Team Leader for UniTrak Corporation Ltd. UniTrak manufactures the TipTrak line of bucket conveyors. For more information email Bransfield at [email protected] or visit www.unitrak.com.

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