How to Reduce Wear on Screw Conveyor Hanger Bearings
28 September, 2026
For plant managers and engineers in the cement industry, few issues are as frustrating and costly as silo flow problems. When cement stops moving reliably, it triggers a chain reaction of production delays, wasted capacity, manual intervention costs, and potential product quality issues. Understanding and preventing the two most common culprits—bridging and ratholing—is essential for maintaining operational efficiency and profitability. This guide will explain these phenomena in detail and outline the most effective strategies to combat them.
Bridging, also known as arching, occurs when cohesive cement particles interlock or bond together, forming a strong, stable arch over the hopper outlet. This arch is capable of supporting the weight of the material column above it, leading to a complete and sudden stoppage of discharge.
Ratholing happens when cement discharges only through a vertical channel directly above the outlet, while the surrounding material remains stuck to the silo walls. This creates a stable, pipe-like cavity (resembling a rat’s burrow) that wastes a significant portion of the silo’s storage capacity.
Both bridging and ratholing are symptoms of funnel flow and are driven by the cohesive strength and moisture content of the cement.
Addressing these challenges requires a combination of the right technology and strategic implementation. Here are the most effective industrial solutions.
How They Work: These systems introduce controlled, low-pressure air into the cement mass through strategically placed pads or nozzles. This aeration reduces internal friction between particles, making the cement behave like a fluid and promoting mass flow.
Why They Work: By breaking cohesive bonds and ensuring first-in-first-out flow, fluidization systems prevent the formation of stagnant zones that lead to ratholing and eliminate the compacted structures that cause bridging.
AKMK Solution: Our Air Flow Aids are engineered for the demanding environment of cement silos, providing reliable aeration to keep your material flowing smoothly and consistently.
How They Work: Mounted externally on the silo or hopper wall, these devices generate high-frequency mechanical vibrations that are transmitted through the structure to dislodge material adhering to the walls.
Why They Work: Vibrators are highly effective at breaking initial bridges and preventing material buildup on sloped surfaces. They provide a powerful external force to initiate flow in problem areas.
AKMK Solution: We offer a range of Pneumatic Vibrators (including ball, piston, and turbine types) designed for heavy-duty industrial use. They can be strategically placed to target specific problem zones.
How They Work: Air cannons store compressed air and release it in a powerful, instantaneous blast through a nozzle directed into the silo. This shock wave effectively dislodges stubborn, established blockages.
Why They Work: For severe bridging or ratholing that other methods cannot break, air cannons provide the necessary high-energy impact. They are the preferred solution for breaking through hardened material.
AKMK Solution: Our technical team can design and support the integration of Air Cannon systems for the most challenging flow conditions.
The optimal solution depends on your specific silo design, the characteristics of your cement, and your operational patterns. Often, a combined approach yields the best results. For example:
Bridging and ratholing don’t have to be an unavoidable cost of doing business. By understanding these problems and implementing the correct engineering solutions, you can achieve reliable, continuous flow in your cement silos.
Are you ready to solve your silo flow challenges? Contact AKMK’s engineering specialists today for a free consultation. We will analyze your specific situation and recommend the most effective and robust solution to keep your operation running smoothly.
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