Differential vertical screw conveyor is a new type of vertical screw conveyor. Its outer cylinder and screw blade rotate in the opposite direction so as to convey bulk materials. Its conveying process is complex. The conveying performance is related to the dimension parameters of mechanism and the properties of granular materials. It is impossible to establish the mathematical equation of the conveying process. Firstly

based on similarity theory

the conveying performance of differential vertical screw conveyor is analyzed

16 important parameters are selected

and the similarity criterion is established. Then

the feasibility of the similarity criterion of differential vertical screw conveyor is verified according to the experimental data of millet conveying and Thai sago conveying on the experimental platform of differential vertical screw conveyor. The results show that the similarity criterion of differential vertical screw conveyor based on similarity theory is relatively accurate.