Should a shafted screw conveyor or a shaftless screw conveyor be selected when conveying granular materials?

Which to Choose for Granular Material Conveying: Axial Screw or Shaftless Screw?

Granular materials are widely encountered in grain, chemical, mining and environmental protection conveying scenarios. Many customers struggle with equipment selection: which is more suitable for conveying granular materials, an axial screw conveyor or a shaftless screw conveyor? Both types have unique advantages. Proper equipment selection can effectively reduce material jamming and wear, and extend the overall service life of the machine.

Materials

An axial screw conveyor is equipped with a solid central drive shaft, with helical blades welded to the shaft, featuring high structural rigidity.

Suitable Scenarios for Granular Materials

Ideal for granular materials with good fluidity, such as grain particles, plastic particles, granular ores and dry granular raw materials.

Advantages

1. High conveying efficiency: The central shaft drives the integral rotation of blades to provide stable thrust, ensuring smooth conveying of granular materials and supporting longer conveying distances.

2. Wear resistance and large load capacity: It is applicable to continuous and large-volume conveying of granular materials with stable performance and excellent durability.

3. Mature and cost-effective: Complete product models and sufficient spare parts supply in the market enable flexible model selection and controllable operating costs.

Disadvantages

1. Risk of material jamming: Gaps exist between the central shaft and the shell, which may cause jamming for bulky or easily tangled materials.

2. Prone to material blockage: Highly viscous and damp agglomerated particles are likely to wrap around the central shaft and cause conveying blockage.

Application Summary: Axial screw conveyors are the preferred choice for dry granular materials with good fluidity.

2. Shaftless Screw: Applicable Granular Materials

A shaftless screw conveyor has no central drive shaft, and materials are pushed forward directly by the integrated rotating helical blades.

Advantages

The absence of a central shaft eliminates material tangling risks and effectively prevents material blockage.

Limitations for Granular Material Conveying

1. Severe wear and high operating cost: Hard and highly abrasive granular materials will cause rapid wear to the blades and lining plates, leading to increased maintenance and replacement costs.

2. Low structural rigidity and limited capacity: It cannot support long-distance conveying and is not suitable for large-volume granular material conveying.

3. Fast blade wear: Blade abrasion is significantly accelerated when conveying high-hardness granular materials.

Suitable Granular Materials for Shaftless Screws

It is applicable to damp, adhesive, semi-wet and easily agglomerated granular materials. Not recommended for dry and hard granular materials.

4. Additional Selection Tips

1. For high-hardness granular materials, thickened wear-resistant screw blades are recommended for both conveyor models to reduce abrasion loss.

2. Check the inner diameter of the screw shell for oversized particle sizes to avoid material jamming.

3. Select the appropriate equipment material according to material temperature and corrosiveness, with carbon steel and 304 stainless steel blades as optional configurations.

Conclusion

In short, axial screw conveyors are preferred for dry granular materials, while shaftless screw conveyors are suitable for damp and agglomerated granular materials. Equipment selection cannot be generalized. Comprehensive consideration of material humidity, hardness, conveying output and distance is essential to minimize equipment failures.