Introduction
Selecting a conveyor for cement, mineral powders or aggregates means matching material, throughput, route and containment requirements. Screw and belt conveyors can both have a role in the same plant. Belts often serve long, high-volume routes, while a compact screw can be practical between a silo and a weigh hopper. Neither technology is the best choice for every duty.
An enclosed cement screw conveyor is one option for a short powder transfer. Compare it with the actual belt configuration being offered, not only an unprotected open belt. This guide covers transport principles, dust control, inclination, footprint and maintenance so the complete systems can be assessed fairly.
Transport principles and suitable materials
A belt carries material on a moving surface supported by pulleys and, commonly, idlers. Conventional troughed belts can move large volumes of sand, gravel, limestone and other bulk materials over long routes. The material generally travels with the belt rather than being continuously pushed through a stationary trough. Loading, discharge, carryback and belt suitability remain important design issues.
An exposed belt carrying fine powder needs attention to wind, spillage, moisture and dust at transfers. That does not make all belts unsuitable for cement. Covered, enclosed and pipe-belt arrangements are available. BEUMER describes a pipe conveyor whose belt forms a tube along the route and opens at loading and discharge; its application information includes cement. Those interfaces still need appropriate containment and cleaning.
A screw rotates a helical flight in a tube or a covered U-trough, moving material through contact with the flight and housing. Cement, mineral fillers and other powders can suit this arrangement when density, flow, wear and temperature are addressed. A tube reduces exposure but does not isolate the material hermetically from all outside air. Flanges, seals, hatches and connected equipment remain part of the boundary.
In a batching plant, the screw may feed cement from a silo toward a weigh hopper while belts handle aggregate. This common arrangement is an application example, not a rule excluding other technologies. A flood-loaded silo outlet needs feeder design; a rotating screw does not deliver an invariant mass per revolution when density and inlet filling change.
Dust control and environmental performance
Dust can affect health, material loss, cleanup and environmental performance. Compare emission paths under loading, running, stopping and upset conditions. An exposed belt may need transfer enclosures, extraction, skirts, belt cleaning and return-run control. A pipe belt encloses much of the route but still opens at its ends. Evaluate the full installation rather than declaring the conveying surface alone dust-free.
A tubular screw has fewer long cover joints than many U-trough arrangements, but its shaft seals, connections and inspection openings can leak. Specify gaskets, seal movement limits, pressure conditions and a vent path for displaced or added air. Housing shape alone does not prove zero leakage or regulatory compliance. Verify the required containment with the actual powder and duty.
Protection from rain and ambient moisture also depends on joints, drainage, storage and operating practice. Enclosure does not remove moisture already in the material or prevent every condensation event. Define acceptable contamination and material condition at the receiver.
Screws often complement longer-distance pneumatic or belt transport by serving a local mixer or weighing point. Accurate mass dosing requires suitable feeding and weighing controls, including cutoff and material in flight. It is not guaranteed simply by using a mechanical screw. See the batch overshoot guide for this interface.
Inclination and footprint
Elevation change, available length, supports and maintenance space constrain any route. A conventional smooth belt’s acceptable incline depends on material behavior and belt design. Steeper-duty belts or other arrangements may be available, so belt conveyors should not all be described as horizontal-only equipment. Compare the offered configuration and its verified capacity.
Screw inclination also changes capacity, fallback and power. There is no universal 20-degree limit and no guarantee of insignificant losses below it. The KWS guide distinguishes inclined designs and explains that trough form, pitch, speed and material affect performance. A tubular housing can help some inclined duties, but does not eliminate gravity or make an ordinary screw suitable for vertical service.
A compact straight screw may fit a short connection with fewer transfers. A belt can be advantageous for a long route and may avoid a chain of mechanical transfer units. Neither turns around an arbitrary obstacle without design consequences. Include drives, guards, extraction, access platforms and room to remove major components when comparing footprint.
For a retrofit, supply the actual elevations, centerline length, obstructions, inlet and receiver positions and structural limits. Ask for capacity and loaded-start confirmation at the proposed angle rather than selecting by an angle claim alone.
Maintenance and operating requirements
Belts need checks of tracking, tension, splices, pulleys, idlers, cleaners, skirts and guards. Their cover compound and construction must fit abrasion, heat and the environment. A closed belt route still needs inspection and access; it does not eliminate moving-part maintenance.
Screws need inspection of flights, housing or liners, shaft and couplings, hanger and end bearings, seals and drive. Wear can change capacity and clearance, while buildup or misalignment can create contact. The relevant intervals depend on material and operating history, not a universal replacement cycle. Safely isolate energy and material before opening or servicing either system.
Compare energy using the same delivered tonnes, elevation and operating schedule. A screw’s sliding and mixing action can impose significant demand; a belt’s long-distance efficiency does not establish its advantage on every short transfer. Include extraction and other auxiliaries. Obtain installed-cost and maintenance estimates for complete alternatives.
For VOGO selection, provide material, bulk-density range, throughput, centerline length, inclination, inlet and outlet arrangement, temperature and electrical supply. Correct configuration supports the required duty, but should not be presented as a guarantee of reduced power or longer wear life without a comparison basis.
Conclusion
Choose by the route and operating evidence. A compact enclosed screw is often worth evaluating for local cement transfer, while belt configurations can serve long routes and can also be enclosed for powder duty. Verify dust control, inclination, feeding accuracy, maintenance access and total operating cost for the actual design.
VOGO’s cement screw catalog lists Ø89–Ø407 mm selection diameters and 1.3–170 t/h reference capacities across configurations. Check the product page and datasheet; confirm project output rather than treating the full catalog range as one machine’s guarantee.
