A screw feeder's job is different from a screw conveyor's — one meters material at a controlled rate out of a hopper, the other moves it from one point to another — but ENZAC builds both on the same core screw platform, in the same two trough configurations. The right one for feeding duty depends on your material and how tightly you need to contain it.
U-Trough (Open) Screw Feeder
An open-top trough is the cost-effective standard configuration, straightforward to access for cleaning and inspection, and suited to most free-flowing to moderately cohesive materials. For metering duty, the open top also makes it easier to visually confirm consistent flow from the hopper above during commissioning and troubleshooting.
Where it fits: Standard powders and granules where dust containment isn't a strict requirement, and where ease of access for cleaning or product changeover matters.
Tubular (Fully Enclosed) Screw Feeder
A fully enclosed tube adds complete containment along the feeder's length — relevant for fine powders, dusty materials, or anywhere dust-tight operation is a requirement rather than a nice-to-have. For a feeder specifically, enclosure also helps hold a more stable fill ratio in the screw, which matters for feed-rate consistency with fine or aerated powders that can behave inconsistently in an open trough.
Where it fits: Fine or dusty powders, combustible dust applications, or hygienic processes where an open trough isn't acceptable.
What Doesn't Change Between the Two
Both configurations are available in mild steel or stainless steel (SS304/316), with wear-resistant or hardened lining options for abrasive materials, VFD-controlled gearmotor drives for speed (and therefore feed-rate) control, and diameters from 150–500 mm covering roughly 1–100 t/hr depending on material properties.
Getting the Choice Right
The decision isn't about which configuration feeds "better" in the abstract — it's whether your material's dust characteristics and your process's containment requirements call for enclosure, or whether an open trough's easier access is the better trade-off for your actual operation. A fine, dusty, or combustible material pushed through an open trough because it was the default choice is a common source of housekeeping and safety issues that a tubular feeder would have avoided from the start.
Ready to talk about your screw feeder?
Review the full Screw Conveyor specification range, or send us your material data sheet and dust classification and we'll recommend the right screw feeder configuration.