Allu Screening Buckets: Versatility, Maintenance, and Field Lessons

[MikePhua]

What Is an Allu Screening Bucket
An Allu screening bucket is a hydraulic attachment designed to process and separate materials directly on-site. Mounted to excavators or wheel loaders, it uses rotating blades or bars to screen soil, compost, demolition debris, or even soft rock. The bucket’s ability to reduce material handling and eliminate the need for stationary screening plants makes it a popular choice for contractors seeking mobility and efficiency.
Key Terminology

• Screening Rotor: Rotating shafts inside the bucket fitted with replaceable wear tips that agitate and separate material.
  
• Case Drain Circuit: A hydraulic return line that relieves excess pressure from the motor, essential for Allu bucket operation.
  
• Fine Bar Configuration: Rotor setup optimized for screening finer materials like topsoil or compost.
  
• Grease Interval: The frequency at which lubrication is applied to moving parts, often hourly in high-wear applications.
  

Operational Insights

• Material Compatibility
  Allu buckets perform best with dry, loose materials. Sticky or clay-rich soils can clog rotors and reduce throughput. Overloading the bucket doesn’t improve efficiency—operators should fill it moderately and allow gravity and vibration to do the work.
  
• Hydraulic Requirements
  Proper hydraulic flow and pressure are critical. Machines must be piped correctly, including a case drain circuit, to prevent motor damage. A mismatch in flow can lead to overheating or poor rotor performance.
  
• Greasing and Lubrication
  Frequent greasing—ideally every hour—is essential. A cordless grease gun is recommended for convenience. Spray lubricants should be applied to chain drives through access plugs to reduce wear and noise.
  

Field Anecdote: Screening in Ireland
A contractor in Cork acquired a 2005 Allu bucket for use on a CAT 312 excavator. Despite its age, the bucket was still on its first set of rotor tips, indicating light prior use. The team planned to screen topsoil from a jobsite but quickly realized the need to upgrade their excavator’s hydraulic plumbing to include a case drain. Once installed, the bucket performed well, though they noted that sticky material reduced efficiency.
Lessons from Demonstration Failures
In South Australia, a crushing contractor tested a similar screening bucket on limestone. The rotors, designed for soil, began crushing the softer stone instead of screening it. The hydraulic system struggled, and the demonstration was halted. This highlighted the importance of matching rotor aggressiveness to material type—some buckets may require less aggressive rotors or alternative configurations for rocky applications.
Best Practices for Allu Bucket Use

• **Grease hourly with manufacturer-recommended lubricant
  
• Use spray lube on chains through side plate plugs
  
• Avoid overfilling—moderate loads screen more efficiently
  
• Hold bucket fully extended and shake when material stops falling
  
• Replace rotor tips regularly, especially in damp or abrasive conditions
  
• Install a proper case drain circuit before operation**
  

Modern Case Study: Soil Remediation in Alberta
A remediation firm used a DS3-17 Allu bucket mounted to a JD 544K wheel loader. As demand grew, they considered mounting the bucket to an excavator for better reach and mobility. The switch allowed them to dig, screen, and pile material in one motion, reducing labor and equipment costs. The team emphasized the importance of training operators to avoid overscooping and to monitor hydraulic temperatures during extended use.
Historical Context: The Rise of On-Site Screening
Before mobile screening buckets, contractors relied on stationary plants that required constant relocation and loader support. The introduction of hydraulic screening buckets in the 1990s revolutionized small-scale material processing. Allu, among the pioneers, offered modular rotor designs and compatibility with a wide range of carriers, making them a staple in landscaping, demolition, and environmental cleanup.
Conclusion
Allu screening buckets offer a powerful blend of mobility and efficiency, but their success depends on proper setup, material compatibility, and disciplined maintenance. From topsoil screening in Ireland to limestone trials in Australia, the lessons are clear: know your material, respect your hydraulics, and never underestimate the value of a well-timed grease job. With the right approach, these buckets can transform how contractors handle earthmoving and material separation.