Archive: Dec 2024

7 Most Common Bulk Materials Prone to Bridging and Ratholing

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Bridging and ratholing are common problems in bulk material handling, and some materials are notorious for poor flow properties. Learn about the most challenging bulk materials and see proof of why AirSweep is the best flow aid for the job.

What are bridging and ratholing?

Bridging happens when bulk materials form a stable arch above an outlet, completely stopping the flow. This usually occurs because of particle cohesion, moisture, or poor hopper design.

Ratholing creates a narrow channel through the material, leaving stagnant product clinging to the container walls. It’s common with materials that have poor flow properties or stick easily to surfaces.

Both problems cause production stoppages, material spoilage, and costly manual intervention—headaches no plant manager wants.

What materials are prone to bridging and ratholing?

Flow problems can be caused by many factors, including vessel design or plant environment (like humidity and temperature). However, these materials have inherent properties that affect how they behave when they are stored, transported, or mixed.

1. Cement and Fly Ash

Cement and fly ash are ultra-fine powders that easily absorb moisture. This leads to clumping, compacting, and cohesion that quickly cause bridging. When stored under pressure, these materials become even tougher to handle because the pressure forces particles closer together, increasing their density and cohesion. The compacted material can form stable arches or stick tightly to hopper walls, making flow nearly impossible without external intervention.

Watch: AirSweep Cement Mix Material Flow Test

2. Food Powders

Most food or beverage processing facilities or commercial bakeries use fine powders like flour, cornstarch, cocoa, and milk powder. These powders are hygroscopic, or readily absorb moisture from the air. Flour and starch compact under their own weight, while cocoa and milk powder stick to hopper walls due to moisture or static charges. These properties make bridging and ratholing and bridging frequent problems.

Food and beverage manufacturers also have to meet strict sanitation standards. Stagnant material can become spoiled, and manually clearing out material blocks may cause contamination.

Watch: AirSweep Moist Cornstarch Material Flow Test

3. Chemicals and Fertilizers

Many chemicals and fertilizers absorb moisture, leading to cohesion and clumping. Granular fertilizers often bridge because of uneven particle sizes, while fine chemical powders compact or stick to equipment surfaces.

Aside from slowing down operations, flow interruptions in fertilizers and chemicals disrupt batching accuracy and downstream processes like mixing and packaging.

4. Plastic Pellets and Resins

Plastic pellets and resins used in plastic production and packaging pose unique challenges. Smooth, spherical pellets interlock under pressure, causing bridging. Irregularly shaped   compact and form stable arches in hoppers.

Recycled plastic and resins also pose more challenges. They have varying particle sizes and shapes, increasing the chances of bridging and compacting. As “green manufacturing” becomes a bigger priority because of sustainability goals, reliable flow systems ensure that recycling operations remain efficient, sustainable, and cost-effective.

Watch: AirSweep Plastic Regrind Material Flow Test

5. Coal and Aggregates

Coal and aggregates are typically used in energy production, mining, and construction. These materials often have irregular particle sizes and varying moisture content. Fine coal dust, in particular, sticks together due to cohesion and compaction. Material blocks can choke boiler feed lines and delay energy production—a costly problem for any plant.

6. Metal powders

Metal powders are extremely fine, dense, and prone to static charge buildup. These properties cause bridging, compaction, and ratholing, particularly in precision processes like additive manufacturing.

7. Sawdust and Wood Chips

Sawdust and wood chips are typically used in paper and pulp industries, wood processing, and biomass energy production. They are lightweight and irregularly shaped, which makes them prone to interlocking and bridging in hoppers and silos. Their fibrous nature also causes the material to compress and compact over time, creating blockages that restrict flow.

Watch: AirSweep Sawdust Material Flow Test 

Solve bridging and ratholing for good

Do you work with a tough material that is prone to bridging and ratholing? Have you tried other flow aids but still resort to manual cleaning or hammering the vessel? AirSweep provides a proven solution to keep your materials flowing, eliminate costly disruptions, and maximize productivity. To learn how AirSweep can improve your plant’s operations, contact us for a consultation.

How to Solve Bridging and Ratholing of Cement and Mined Materials

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Material flow is the backbone of any successful operation in the mining and cement industries. Yet, common issues like bridging, ratholing, and material pileups can derail even the best-laid plans. These disruptions not only impact productivity but also drive up costs with additional labor and energy consumption.

The solution? AirSweep—a proven flow aid trusted by over 10,000 installations worldwide. Designed to handle the heavy-duty challenges of materials like clinker, fly ash, and copper concentrate, AirSweep ensures consistent material flow, minimizes downtime, and keeps operations running smoothly. Read on to discover why AirSweep outperforms traditional flow aids and how it’s revolutionizing bulk material handling in the cement and mining industries.

Common material flow problems in mining and cement

Heavy materials like clinker, fly ash, and copper concentrate pose significant challenges in processing plants. They often:

  • Bridge or rathole inside vessels, reducing live capacity.
  • Plug outlets, halting production lines.
  • Segregate particles, disrupting material quality.
  • Flood or flush fine powders, causing inefficiency and waste.

Traditional flow aids like vibrators, air cannons, and fluidizers are no match for such issues. They can compact materials, waste energy, or create safety risks by dispersing particles.

common material flow problems of cement and mined materials

AirSweep flow aids solve the toughest flow problems of cement and mined materials.

 

Why AirSweep is the best flow aid for cement and mined materials

AirSweep releases high-pressure, high-volume, 360-degree pulses of compressed air that break through material blocks and clear vessel walls. It’s efficient, safe, and designed to tackle the toughest materials. It’s also more efficient, safe, and cost-effective than other flow aids.

  • Fluidizers fail to activate heavy materials.
  • Air cannons waste energy and spread material dangerously.
  • Vibrators compact materials instead of clearing them.

AirSweep, on the other hand, activates materials quickly and completely, using less energy and plant air.

AirSweep is trusted by cement and mining companies worldwide

AirSweep has consistently delivered outstanding results across the mining and cement industries, solving some of the toughest material flow challenges.

For a leading cement manufacturer, conventional air cannons failed to eliminate stubborn clogs and clinker, forcing workers to break blockages manually using bars—a time-consuming and inefficient process. By switching to AirSweep VA-51 units, the company significantly improved efficiency, completely eliminating residue buildup. The success was so remarkable that they implemented the system across multiple plants.

In the mining sector, a company handling copper concentrate faced daily disruptions, with workers spending up to two hours clearing material blockages. Air cannons posed safety hazards by dispersing materials, while vibrators were both noisy and ineffective. Installing three AirSweep VA-12 units transformed their operations, providing a quiet and effective solution that allowed workers to redirect their efforts to other critical tasks.

For a concrete company dealing with fly ash, material bridging around vessel outlets brought production to a standstill. Four AirSweep units were installed while approximately eight tons of fly ash remained in the bin. The result? Production went from zero to full capacity overnight, ultimately boosting overall output by 60%.

These real-world applications highlight AirSweep’s ability to optimize material flow, reduce labor, and enhance productivity in even the most demanding environments.

Fits Every Vessel, From Silos to Trucks

AirSweep can be installed on all types of bulk material handling equipment, from silos and hoppers to truck trailers. The wear plates and hard-facing AirSweep units can be bolted on flat walls or surfaces to protect equipment. In truck applications, AirSweep proves equally effective, activating materials during transport to guarantee smooth and efficient unloading.

AirSweep can be installed on equipment used to transport cement and mined materials.

 

Built for Durability and Performance

AirSweep systems come with the longest warranty in the business—seven years—a testament to their reliability. Whether you need to clear stubborn clogs in silos or ensure smooth transport in trailers, AirSweep delivers unmatched performance.

Ready to revolutionize your operations? Contact the AirSweep team today to find out how we can optimize your material flow and prevent costly downtime.