Optimized installation angle and distance of a grading channel for dried jujube fruit with a push-pull actuating mechanism

Abstract

Grading dried jujube fruit would improve economic efficiency of fruit production and allow more rapid industrial development of this process in China. The common grading mechanism of dried jujube is air-blowing, which causes little mechanical damage but requires a complex mechanical structure that requires significant space. This work describes a system with a push-pull actuating mechanism that offers easy operation and a simpler structure that requires less space. However, components of this mechanism might cause mechanical damage to dried jujube. The mechanical damage to the fruit is positively correlated with the collision kinetic energy caused by movement in the grading channel. With a goal to minimize mechanical damage, this study was designed to analyze the main factors related to the collision kinetic energy of dried jujube fruit, the installation angle and distance of the grading channel. By theoretical calculation, the appropriate ranges of installation angle and distance were determined as 30–60° and 10–30 cm, respectively. After that, capturing video images at different angles and distances using high-speed camera and then analyzing these video images using computer, the experimental results were obtained and showed that the collision kinetic energy was reduced with increased installation angle, and increased with increased installation distance. Accordingly, the optimized installation angle and distance were 60° and 10 cm, respectively, and the maximum collision kinetic energy on dried jujube fruit was 0.058 J, a level unlikely to cause mechanical damage.