One or Two Waste Grab Cranes? Maximize Plant Reliability

• Unexpected Downtime: Mechanical failures, electrical issues, or routine maintenance can halt waste handling.
• Reduced Plant Availability: Every hour the crane is offline directly impacts the feeding schedule.
• Safety Concerns: Overloading or rushing the crane during peak operation increases accident risk.
• Financial Impact: Lost throughput translates to lower revenue and potential penalties in contracted waste processing.

Even cranes with excellent maintenance cannot fully eliminate failure risk. Plants handling large volumes or running continuously face significant vulnerability with a single crane.

A dual waste grab crane system involves two cranes installed on the same bunker or feeding area. The second crane can function as:

• Standby Crane: Activated only when the primary crane is offline.
• Parallel Crane: Both cranes operate simultaneously, increasing handling capacity and operational flexibility.

This setup allows continuous operation, scheduled maintenance without production stops, and improved overall plant availability. It embeds reliability directly into waste handling rather than reacting to downtime after it occurs.

Downtime is not limited to catastrophic failure. Typical scenarios include:

• Mechanical issues: Worn grab teeth, broken hoist cables, or motor faults.
• Electrical problems: Control system errors, short circuits, or power interruptions.
• Operational delays: Misalignment with hoppers, jams caused by oversized waste, or operator errors.
• Routine maintenance: Even planned inspections can cause hours of lost operation if no backup exists.

Most MSW plants experience at least one unexpected crane downtime per month, making redundancy a practical necessity.

• Lost throughput: Every hour of crane downtime reduces tons processed, impacting revenue.
• Higher emergency repair costs: Quick fixes often require overtime labor and expedited spare parts.
• Contractual penalties: Delays can trigger fines in plants with daily processing agreements.
• Increased operator stress: Crane failure may force rushed processes or unsafe workarounds, risking accidents and additional costs.

While a single crane may appear cost-effective initially, hidden operational and financial risks often outweigh the savings.

In parallel operation, both cranes operate at the same time to handle waste. This setup is common in high-throughput plants where a single crane cannot meet daily demands.

• Large bunkers with long spans where a single crane is inefficient.
• Plants experiencing peak feeding times exceeding one crane's capacity.
• Facilities requiring flexibility and faster handling for varying waste volumes.

Advantages:

• Increases daily throughput and reduces cycle time.
• Provides operational flexibility: if one crane stops, the other continues at reduced efficiency.
• Balances wear and tear across both machines, potentially extending lifespan.

The differences between standby and parallel operations is essential for choosing the right strategy:

Some plants even combine strategies: one crane runs normally, while the second alternates between standby and partial parallel operation during peak loads for flexibility and resilience.

Routine inspections and preventive maintenance can be scheduled without interrupting plant operations with a dual crane setup.

• One crane handles regular operations while the other undergoes maintenance.
• Maintenance can occur during lower-load periods, reducing operator stress.
• Spare parts and service teams can work efficiently without causing emergency stoppages.

This flexibility minimizes downtime risk and makes maintenance less disruptive, an advantage often overlooked when evaluating the cost of a second crane.

Dual cranes also improve safety and efficiency in day-to-day operations:

• Operators avoid rushing a single crane during peak loads, reducing accident risk.
• Workload is distributed, minimizing wear on motors, hoists, and grabs.
• Better positioning and handling in long or irregular bunkers improves precision and reduces waste spillage.

These improvements protect personnel, extend equipment life, and make daily operations smoother.

A dual crane setup can generate ROI by improving plant reliability and productivity:

• Reduced downtime: If one crane fails, the other keeps operations running.
• Higher throughput: Parallel operation or standby usage allows more waste handling during peak periods.
• Optimized workflow: Operators can plan crane use efficiently, reducing cycle times and delays.

Many plants recoup a significant portion of the investment quickly, as avoided downtime alone can offset costs within months to a few years.

Beyond financial returns, a second crane provides practical risk management advantages:

• Reduced emergency repair costs: Urgent repairs can be scheduled during normal maintenance windows.
• Extended equipment life: Sharing workload reduces wear on motors, grabs, and hoists.
• Operational consistency: Reliable crane coverage ensures feeding schedules, contracts, and safety standards are met consistently.

Investing in a second crane safeguards plant operations and reduces long-term operational and financial risks.

Use this framework to guide your decision:

When a Standby Crane Works Best:

• Moderate waste volumes with predictable schedules.
• Desire to minimize wear and operational costs.
• Maintenance windows are tight or inflexible.

When Parallel Operation Makes Sense:

• High daily throughput or large bunkers.
• Need to reduce cycle times and maximize daily handling.
• Maintenance and operators can manage coordination between two active cranes.

Pro Tip: Many plants combine strategies. One crane handles normal loads while the second remains on standby. During peak periods, both cranes operate in parallel, balancing cost, reliability, and efficiency.

• Simulate Failure Scenarios: Test the system as if the primary crane fails, verifying that the backup crane can handle full load safely.
• Check Coordination in Parallel Mode: If both cranes operate simultaneously, ensure they move without interfering with each other or creating safety hazards.
• Routine Trial Runs: Schedule periodic redundancy tests to catch potential issues early and maintain operator readiness.

These practices confirm that the dual crane system improves plant availability rather than just adding equipment.

• Future Bunker Expansion: Ensure the second crane's reach covers potential future bunkers or feeding areas.
• Increased Throughput Requirements: Select cranes that can handle higher loads or faster cycle times if production increases.
• Compatibility with New Equipment: Make sure crane controls, hoists, and grab types remain compatible with other plant upgrades.

Designing a dual crane system with expansion in mind prevents costly retrofits and maintains operational flexibility for years.