Material Handling Solutions
The SilMan Parcel Air Ejection System
Misaligned Parcels in Cross-Belt Sortation
In high-velocity distribution centers, even minor disruptions can cascade into significant operational losses. The Parcel Air Ejection System, also known as “Air Knife,” addresses one of the most persistent challenges in cross-belt sortation: packages that migrate to an unsortable position or land in the bellows—those critical gaps between sort belt modules that allow conveyors to contract and expand on curves.
Misaligned packages reduce capacity as positions are locked, and inevitably, team members must pause the system to recover the items and manually reintroduce them into the sortation system.
Despite their small share of total packages, unsortable parcels incur significant financial and efficiency losses.
How It Works
The air knife operates with remarkable precision and simplicity. A camera continuously monitors the bellows segments, capturing images at speeds matching the 2.5m/second conveyor velocity. When the system detects a stranded package, it calculates the exact moment the item will pass the ejection zone.
At that precise instant, a high-velocity blast of air from a strategically positioned nozzle sends the misplaced package into the “problem solve” chute.
The entire detection-to-ejection cycle happens in milliseconds, maintaining the conveyor’s continuous operation.
Measurable ROI and Operational Value
The financial justification for the air knife parcel ejection solution is compelling and quickly realized—often within weeks of installation. Consider the actual cost of a single conveyor stoppage: lost throughput, labor costs for manual removal, delayed shipments, and the ripple effects throughout your operation. By eliminating these interruptions, facilities enjoy a range of gains.
| Throughput Gains | The solution maintains sorter capacity by increasing uptime for all cross-belt modules. Continuous operation without jam-related stoppages increases daily package processing capacity, depending on existing jam frequency. |
|---|---|
| Labor Savings | Eliminating manual interventions reduces labor costs associated with clearing jams and reallocating workers to value-added activities. |
| Maintenance Reduction | The system’s automated operation minimizes wear on conveyor components and reduces the need for emergency maintenance calls. The blower automatically enters energy-saving mode during sort pauses, and only routine filter replacements are required. |
| Safety Improvements | Eliminating the need for workers to interact with moving conveyors during jam events significantly reduces the risk of injury and workers’ compensation claims. |
Air Knife Parcel Ejection System Step-by-Step
- The air ejection process begins with the Cognex Vision System. Located closely upstream of the ejection zone, the sensor detects misaligned packages as they approach.
- A proximity sensor detects when the parcel is aligned with the air nozzles and communicates with the actuator to release air.
- A pneumatic solenoid actuates the Y-Verter, which diverts the air to the nozzle, blowing the misplaced package from the conveyor into the “jackpot” chute.
Note that even when appearing idle, the centrifugal blower is constantly and quietly pushing air through a muffler, primed and ready for activation.
Implementation
Since 2020, SilMan has provided over 200 systems. These experiences have provided our Specialty Trade Services team with an opportunity to systemize the installation to create a National Program. The result is a seamless, efficient process that adds additional value to the cost-saving benefits of the Air Knife.
System Capabilities and Specifications
The Air Knife can blow 8 lb packages in optimal conditions. However, the primary targets are smaller parcels and envelopes that commonly cause bellows jams. The system integrates seamlessly with existing infrastructure, requiring only:
- 480V three-phase power connection
- Standard 90 PSI compressed air supply (minimal consumption)
- Ethernet connectivity for controls integration
Each central control panel supports up to ten Air Knife units, enabling cost-effective scaling across multiple sortation lines. The system’s flexibility allows installation in various configurations, including double-stacked sorters and facilities with limited floor space.
The Bottom Line
In an industry where efficiency gains are measured in fractions of percentages, the Air Knife Parcel Ejection System delivers measurable, immediate improvements. By converting a manual, reactive process into an automated, preventive solution, distribution centers achieve the dual benefits of increased throughput and reduced operational costs. The SilMan solution has consistently demonstrated its value across over 200 installations, proving itself an essential component of modern sortation systems—one that pays for itself while improving operational metrics and workplace safety.
About the Company
SilMan Industries (previously SilMan Construction) is based in San Leandro, Calif., with Engineering and Field Operations offices in Tupelo, Miss. The firm provides integrated turnkey solutions in the Industrial, Manufacturing, Distribution, and Public Works sectors.
Notably, in 2010 SilMan Industries was contracted to dismantle and remove the NUMMI assembly line in Fremont, Calif., transport the equipment, and reinstall the system in Blue Spring, Miss., establishing Toyota Motor Manufacturing Mississippi (TMMMS). This high-visibility project ignited the company’s meteoric growth, laying the foundation for SilMan’s national service area.
For more information, please visit www.silmanindustries.com/about.
Frequently Asked Questions for Parcel Air Ejection Systems
What is a parcel air ejection system and how does it work?
A parcel air ejection system, often called an "Air Knife," is an automated solution designed to remove misaligned packages from cross-belt conveyors. Using high-speed cameras and vision sensors, the system detects misaligned packages and those stranded in conveyor bellows and triggers a precise, high-velocity blast of air to divert the item into a "problem solve" chute without stopping the line.
How does an automated air knife improve conveyor throughput?
The automated air knife solution automatically ejects unsortable items without slowing or stopping the conveyor. This allows the system to stay in continuous operation. Beyond optimizing capacity by maximizing the available sorting positions and sortation rates, labor effectiveness is improved by reducing the time spent retrieving packages.
What are the technical requirements for installing a SilMan Air Knife system?
The SilMan Air Knife system is designed for seamless integration with existing infrastructure. It requires a 480V three-phase power connection, a standard 90 PSI compressed air supply with minimal consumption, and Ethernet connectivity for controls integration. Each control panel can support up to 10 individual units, enabling scalable deployment across multiple lines.
