Problem: dust
Dust at a conveyor transfer point
Dust at a conveyor transfer point is usually driven by falling material, displaced air and poor sealing. Understanding which of these dominates is the first step towards choosing between containment, wet suppression and dry fog.
Symptoms and likely causes
What you may be seeing
- Dust clouds at chute openings and along the belt edges
- Dust settling on idlers, structures and walkways near the transfer
- Spillage and build-up under the loading zone
- Worn or missing skirt seals and curtains
- Off-centre loading and high drop height
- Fine, dry material with little natural moisture
Why transfer points release dust
When bulk material drops from one belt to another, it accelerates, spreads out and draws air in with it. On impact at the receiving belt, that entrained air is released along with fine particles stripped from the stream. If the chute or skirt boards are not sealed, the pressurised dusty air escapes at the openings, belt edges and tail end. Higher drop heights, greater throughput, dry and fine material, misaligned loading that pushes material off-centre and worn skirt seals all increase the effect. Belt carry-back that dries and falls from the return run, and spillage that is crushed under idlers, can add further dust that is sometimes mistaken for transfer-point emission.
Options to consider
The first options are mechanical: reducing drop height or using a chute that guides material onto the belt, improving skirt sealing, adding a settling zone and curtains so dusty air slows down, and fitting belt cleaners. Suppression then addresses the dust that remains. Water sprays wet the material before or at the transfer so fines stay bound, which suits materials that tolerate moisture. Dry fog captures airborne particles inside the enclosure with little added moisture. Dust extraction to a collector is another route where moisture is unacceptable or emissions must be captured. Often a combination is used.
Questions that decide the answer
- What material is handled, and how fine and dry is it?
- What is the throughput, belt width and drop height?
- How enclosed is the transfer, and where are the openings?
- How much added moisture can the material and process accept?
- Are water, compressed air and power available at the transfer?
- Can drawings or photographs of the chute and skirt arrangement be shared?
Options
Possible approaches
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Frequently asked questions
Should I fix the chute before adding suppression?
It is worth reviewing the chute, skirt sealing and loading alignment first, because they influence how much dust is generated and how much air escapes. Suppression works better when the transfer is reasonably enclosed and the amount of displaced air is controlled.
When is dry fog preferred over water spray at a transfer point?
Dry fog is usually considered where the transfer is enclosed and the material or downstream process cannot accept much moisture. Water spray is often simpler where the material tolerates wetting. The choice depends on the material, enclosure and utilities available.
What information should I gather first?
Note the material, throughput, belt width, drop height, how enclosed the transfer is, any moisture limit, and whether water, compressed air and power are nearby. Photographs of the chute, skirt boards and dust release points are very helpful for review.
Describe the problem. We’ll help frame the solution.
Share a part number, a drawing or simply the problem. Unknowns are fine — an engineer will review your enquiry.