Author：yilida Time：2026-10-08 11:54:11 Number of views：184Second-rate
Once a dust collector has done its job, the collected material has to go somewhere. The unglamorous hero of that step is the screw conveyor. Quiet, sealed, and compact, it moves fine dust and bulk solids from hoppers to silos or disposal without raising a cloud. In a dust collection system, the screw conveyor is what turns captured particulate into a handled, contained stream.
This guide covers how screw conveyors work, trough vs tubular designs, how to size capacity, and how to apply them reliably in dust and ash handling.
A screw conveyor (auger conveyor) moves material along a trough or tube using a rotating helical flight on a central shaft. Material is fed at one point and advanced by the turning screw to the discharge. Because it is fully enclosed, it contains dust during transport—critical when the product is fine, airborne, or hazardous.
| Type | Characteristic | Best use |
|---|---|---|
| Trough (U-shape) | Open top with cover, easy access | General dust, ash, accessible plants |
| Tubular (pipe) | Fully enclosed, better sealing | Fine, dusty, or toxic material |
| Shaftless | No center shaft, handles stringy/wet | Sticky or irregular material |
An enclosed screw conveyor does double duty: it transports material and it contains the dust, so the collection system's emission control is not undone at the discharge stage.Bulk material handling practice
Conveying capacity depends on screw diameter, pitch, rotational speed, and the material's bulk density and angle of repose. Oversizing wastes power; undersizing causes backups and hopper bridging. A standard formula estimates volumetric throughput from diameter, pitch, rpm, and a fill-factor allowance for the specific material.
Diameter: larger screw moves more, but needs more torque.
Pitch: standard pitch equals diameter; reduced pitch controls flood-feeding.
Speed: higher rpm increases capacity but raises wear and dusting risk.
Fill factor: abrasive or sluggish materials need a lower fill factor.
Screw flight and shaft — carbon or stainless, hardened for abrasive ash.
Trough or tube — sealed, with inspection ports.
Drive unit — gearmotor sized for starting torque and material load.
Inlet and outlet — matched to hopper and downstream equipment.
End bearings and seals — to keep dust in and contamination out.
Abrasive fly ash is among the harshest duties for a screw; specifying hardened flights and proper seals is what separates a conveyor that lasts from one that erodes within a season.Abrasive material handling guidance
Baghouse and ESP hoppers — moving collected dust to silos.
Power plants — fly ash and bottom ash handling.
Cement and minerals — raw and finished powder transport.
Chemical and food — enclosed, contamination-controlled transfer.
Define material: bulk density, particle size, abrasiveness, moisture, temperature.
Calculate required throughput with a conservative fill factor.
Choose trough vs tubular vs shaftless for the duty.
Size drive for starting torque, not just running load.
Plan bearing and flight inspection; replace worn flights before failure.
For fine dust and powdered material, an enclosed screw contains the product and prevents dusting, whereas a belt exposes material and needs skirting and dust control.
Screws are not ideal for very abrasive, high-temperature, or fragile material that degrades on contact; they also have a practical length limit before needing intermediate bearings.
Use tubular or well-sealed trough designs with proper shaft seals and balanced hopper discharge so air does not short-circuit through the screw.
Yes with high-temperature materials, but cooling or indirect designs are often needed above certain temperatures to protect seals and bearings.
Overfeeding, oversized lumps, or material bridging in the trough; correct inlet design and speed control prevent most jams.
Highly variable; abrasive ash may wear flights in months without hardening, while gentle powders last years. Inspection intervals should match the duty.
A screw conveyor is the quiet link that completes a dust collection system: it transports collected material in an enclosed path so the emission control achieved at the filter is not lost at the hopper. Botou Yilida Environmental Protection Machinery Equipment Co., Ltd. supplies trough and tubular screw conveyors, rotary airlocks, bucket elevators, and humidifiers as part of complete dust handling packages. To size a conveyor for your hopper discharge and material, contact the Yilida team via www.yilida-dustcollectors.com.
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