Built to Last, Engineered to Evolve: How GEMCO Retrofitted a Legacy Dryer for a Highly Explosive Powder 💥

Some machines are built to last. At GEMCO, we build them to evolve, too.

When a client approached us to retrofit a vintage GEMCO dryer, originally manufactured in 1968, for a modern, high-risk application involving an extremely explosive powder, we knew this was more than a tune-up. This was a transformation.

Understanding the Risk

The powder’s characteristics presented a serious engineering challenge:

🔧 Extremely high Kst and Pmax

🔧 Low minimum ignition energy (MIE)

🔧 Possible shock sensitivity

The powder in question had a Kst value of 416—well above the 300 threshold for “very strong” explosions—and a Pmax of 16.2 bar, more than twice the pressure typical of hazardous metal powders. Combined with the other characteristics, safety couldn’t be a feature—it had to be built into every component, every function, and every fail-safe.

Our Approach: Practical Engineering for Critical Materials

While rupture discs are often requested for explosive environments, their use on rotating equipment comes with drawbacks. The dynamic forces generated by powder movement can unintentionally load the disc, potentially compromising its reliability. We’ve tested workarounds like screens and alternate disc positioning—but in most cases, they limit the disc’s effectiveness. For this application, we strongly recommend keeping rupture discs as a last resort, not a core strategy.

Inert Atmosphere Integration
The entire vessel was modified to support blanketing with inert gases, like nitrogen or argon, to eliminate oxygen and lower the risk of combustion. This isn’t just best practice—it’s a baseline for handling energetic powders safely.

Monitoring and Pressure Control
To prevent dangerous pressure buildup, we integrated pressure sensors to monitor both the filter and vacuum pump. These sensors track pressure differentials (ΔP) in real-time—providing early warning for filter clogging or abnormal vacuum behavior.

Static Dissipation
To prevent ignition from electrostatic discharge, we added static dissipators that safely route built-up charge to ground. It’s a simple but critical safeguard when working with highly reactive powders.

Environmental and Control Safety
The controls were purged to be safely operable within an explosive environment, with an option to relocate the main control panel to a remote utility space. For in-room operations, a secondary HMI was installed to maintain functionality without compromising safety.

Fail-Safe Engineering
We integrated fail-safe braking systems to ensure the dryer remains completely stationary in the event of air loss, preventing any unintended movement. In addition, spring-return valves were added to automatically close if power is lost—an essential safeguard to keep fine, reactive powders securely contained within the vessel and preserve overall system integrity.

Retrofitting with Purpose

What makes this project remarkable isn’t just the safety technology—it’s that all of it was engineered into a legacy GEMCO unit built decades ago. We didn’t just make it compliant; we made it capable of handling one of the most explosive powders in industrial use today.

This is what we mean by “built to last, engineered to evolve.” Our equipment doesn’t just survive—it adapts to meet the needs of the industries we serve, from food and pharma to defense and energetics.

Have legacy equipment that needs to meet new safety or process demands?
Reach out to our team of experts to start the conversation.
parts@okgemco.com
732.733.1158