Many plants see “clean averages” but alarming peaks during powder transfer. Those spikes drive exposure, trigger alarms, and spread contamination. Understanding the physics helps you stop them at source.

What drives the spikes

When powder drops or is poured, it displaces air, pushing a plume outwards. Turbulence at edges, poor seals, static attraction, and sudden surges (bag dumping or auger restart) break agglomerates and loft fine particles. The first seconds of start-up and the final trickle at shut-off typically produce the largest bursts.

Where they occur

Bag emptying into hoppers, transfer between drums, manual top-ups, and clearing blockages all create rapid pressure and velocity changes. Lids left open and long free-fall distances magnify the effect.

How to reduce peaks

Slow the feed, reduce drop height, and baffle the inlet. Fit seals and ensure the lid is the only opening. Create a slight inward airflow across the opening with local exhaust ventilation and verify capture with smoke. Keep background air stable by placing an air scrubber to pull air away from operators; units such as MAXVAC Dustblockers can help stabilise general levels when positioned correctly.

Measure to manage

Use air monitoring during representative transfers—place a PM meter near the breathing zone and another downwind to map plumes. Look for peaks at start/stop, then adjust feed rate, hood position, and enclosure gaps until spikes flatten. Record airflow under load and note filter loading over the shift.

Practical takeaways

• Expect spikes at start-up, surges, and shut-down—control these moments.
• Seal gaps, shorten drop distances, and pull air inward at the opening.
• Position extraction using smoke tests; verify airflow under load.
• Use air monitoring to confirm that peaks are reduced, not just averages.

By managing displacement air and turbulence, you convert unpredictable peaks into steady, controlled transfer with lower exposure and cleaner production.