Design and Experimentation of a Flotation‐Based Dual‐Layer Roller Squirrel‐Cage Fresh Goji Berry Grader

ABSTRACT This study addresses the issues of low efficiency, high damage rate, and insufficient classification accuracy in fresh goji berry grading processes by designing and developing a double‐layer roller‐cage type fresh goji berry grading machine based on flotation technology. The equipment comprises three main components: a feeding structure, a grading system structure, and a water circulation discharge system structure. First, based on flotation technology principles, the structural parameters of the double‐layer roller‐cage were determined: cage length of 2.1 m, inner cage diameter of 0.34 m with roller diameter of 10 mm, outer cage diameter of 0.58 m with roller diameter of 8 mm, and cage inclination angle of 16.21°. Numerical simulations of the grading process were conducted using ANSYS Fluent software to verify parameter rationality, establishing optimal operational parameters including water flow velocity of 3.0 m/s, volumetric flow rate of 1.5 × 10 −2 m 3 /s, and cage rotation speed of 12 r/min. Experimental results demonstrate that the grading machine achieves an average accuracy of 93.82%, a nondestructive rate of 98.20%, and an average production capacity of 1020.5 kg/h, meeting design specifications. These findings indicate that the equipment effectively enhances fresh goji berry grading efficiency while providing a novel technological approach for mechanized classification of small berries. Future research will focus on optimizing feeding mechanisms and water circulation systems, integrating machine vision technology to improve grading precision, enhancing equipment stability and resource utilization efficiency. Additionally, exploration of its potential applications in other berry classification scenarios will be conducted to expand its industrial applicability.