General limitations of screw conveyors

1 Screw conveyors are not self-cleaning as product will rest in the clearance space essentially allowed between the screw flights and casing to prevent metal contact. Cross contamination, product degradation or unwanted residue may result. 

2 Shaft deflection limits the single span length of a screw. Whilst intermediate bearings are commonly fitted to secure longer conveying lengths, they introduce extra pockets of residue, routine maintenance demands and in some cases can be a perennial nuisance. 

3 They are mechanical inefficient compared with belt conveyors and less cost-effective on extended lengths and for very high transport capacities. 

4 High power loads may be experienced when starting under full conditions and running empty or under light load conditions is mechanically inefficient. 

5 Hard pieces, particularly taper shaped or materials that laminate, can jam in the clearance space between the screw flights and the casing. 

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