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Conveying Lumpy Materials: Four Tips

January 5, 2022

Some materials are inherently lumpy while others can become so during storage as the material particles become compacted and agglomerated. An example of the latter is powdered cement: this material is hygroscopic and its particles will tend to clump together from exposure to humidity during storage. Due to particle clumping, lumpy materials are often hard to handle and convey, causing process interruptions and lost throughput.This blog looks at some of the issues that need to be addressed for successfully conveying lumpy materials.


The following tips have proven useful for overcoming the challenges associated with conveying lumpy materials.

Tip #1: Ready the material for conveying.
Preparing a material by reducing the size and number of lumps will make it easier to handle when conveyed. Certain mechanical conveyor types, such as aeromechanical or flexible screw conveyors, may be difficult or impossible to feed if lumps are not broken up or reduced in size so that the material may readily enter and move through the conveyor’s infeed inlet. Other mechanical conveyor types, such as continuous bucket elevators, may be more forgiving of lumps, but even here lumps need to be reduced in size so that as near as possible the target bucket fill rate can be achieved.

Tip #2: Break up clumped material.
Materials that have been stored may become compacted and agglomerated. For example, the lower layers of bagged materials stored on pallets may be severely compacted and the particles clumped together into a single or several masses. These masses must be broken up before the material can be fed into and moved through a conveyor.

Tip #3: Reduce the material as it moves through processing stages.
Conveyors typically move material between processing stages. Even if lumpy material successfully moves through a conveyor, the presence of these lumps can further hamper downstream processing. Using lump breakers and crushers to reduce lumps prior to feeding a conveyor can address the dual challenges of material movement and processing.

Tip #4: Choose appropriate conveying technology when moving lumpy materials.
Unless the first three tips are implemented, successfully conveying lumpy materials will always be challenging no matter whether pneumatic or mechanical conveyors are employed. Viscous materials which adhere to conveyor parts, resulting in clumping and lumping, require the use of conveyors whose design reduces the incidence of material adherence. For example, shaftless flexible screw conveyors, such as the UniFlex design from UniTrak, can address this problem through the absence of a shaft which presents less surface area for viscous material to affix itself to.

If your application involves the conveying of lumpy materials, UniTrak may be able to help. Combining our nearly 50-plus years of experience with a proven lineup of high-reliability conveyors, we have the capabilities for addressing the challenges associated with moving bulk solids materials. The UniTrak product lineup includes TipTrak™ continuous bucket elevators, Powderflight aeromechanical conveyors, UniFlex flexible screw conveyors, and Bagstander bulk bag dischargers and fillers. To find out how we can service your needs, please contact our sales team for an application review.

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