Objective To address the problems of complex material composition, easy fruit damage, and difficult separation and cleaning after the mechanized harvesting of frozen sea buckthorn fruit, this study designed a new device for multi-stage threshing and double-layer screening of frozen sea buckthorn fruit and conducted a simulation analysis.

Method The core components of the device are a three-stage threshing roller and a double-layer drum screen. Theoretical calculations were used to determine the key structural parameters of the threshing roller and the double-layer drum screen. The finite element method was used to conduct static stress and modal analysis on the threshing roller to verify its structural strength and operational stability. A 3D model was created in SolidWorks and imported into EDEM discrete element simulation software for analysis. To find the optimal operating parameters, a three-factor, three-level Box-Behnken experiment was conducted with the threshing roller speed, double-layer drum screen speed, and feeding rate as the experimental factors, and the separation rate and impurity content as the evaluation indicators. A quadratic polynomial regression model was established between the factors and the evaluation indicators using the response surface methodology.

Result All factors had a significant or highly significant effect on both the separation rate and impurity content, the speed of the drum is the most important factor affecting the separation rate and impurity content. The optimal parameter combination determined by multi-objective optimization was: threshing roller speed of 466.2 r/min, double-layer drum screen speed of 34.7 r/min, and feeding rate of 1.246 kg/s. Under these conditions, the predicted separation rate was 86.245%, and the impurity content was 9.737%.

Conclusion The multi-stage threshing and cleaning device for frozen sea buckthorn fruit designed in this study can effectively solve the material handling challenges after mechanized harvesting. It provides a theoretical basis and technical support for the research and development of high-efficiency, low-damage equipment for post-harvest processing of frozen sea buckthorn fruit.