Design and parameters optimization of the curved sieve for an air suction jujube harvester

In order to improve the screening performance and cleaning effect of the jujube harvesting machinery cleaning device, a vibrating curved screen device was designed in this study. By analyzing the structure mechanism of the curved sieve body, it was obtained that the arc-shaped mesh hole spacing S was 15-25 mm and the curved mesh hole curvature U was 90°-150°. By exploring the movement state and stress of jujube and impurities on the curved sieve body, it was determined that the horizontal spacing L of the curved layer sieve was 30 mm and the vertical spacing H was 45-65 mm. Taking the vertical spacing H of the curved layer sieve, the curvature U of the curved mesh hole, and the spacing S of the curved mesh hole as the experimental factors, considering the screening efficiency α and the impurity content β of the jujube as the response values, the three-factor three-level quadratic regression orthogonal experiment was designed, establishing the regression mathematical model of each factor and response value, and the multiple target optimization algorithm of Design-expert software was used to optimize various factors. The results showed that the influence factors on the screening efficiency were in the descending order as: the arc screen spacing, the vertical spacing of the curved layer screen, and the curved screen hole curvature; The significant factors affecting the impurity content of jujube were in the descending order as: the arc screen spacing, the curved screen hole curvature, and the vertical spacing of the curved layer screen. The experimental results were verified by the optimized combination of parameters: when the vertical spacing H of the curved layer screen was 65 mm, the curved screen hole curvature U was 110°, and the arc screen spacing S was 23 mm, the average screening efficiency α in the test was 91.09%. The relative error between the experimental verification value and the theoretical optimization value was 1.36%, which was less than 5%. The impurity content of jujube β in the test was 1.02%. The relative error between the experimental verification value and the theoretical optimization value was 2.00%, which was also less than 5%. The test results can provide a reference for the research and optimization of the subsequent air-suction-type jujube harvester cleaning device.