点胶-纸带式小粒径种子蔬菜精密播种机设计与试验.

A high-precision mechanized seeding can greatly contribute to the vegetable production at present. In this study, a spotting glue-paper tape precision seeder was designed for the small seed vegetables, particularly combining the seed rope and printing seeding. Three components were also divided in the seeder, including the peristaltic pump glue, ratchet spotting glue, and seed metering device. Among them, the glue was a mixture of pregelatinized starch and water. Specifically, the glue volume and viscosity were the main factors affecting the number of adhered seeds. The glue point volume depended mainly on the rotation angle of the peristaltic pump during the movement. A pretest of seed adhesion was carried out to preliminarily determine the mass ratio of pregelatinized starch to water (less than 1:5), representing the glue viscosity. Furthermore, the frequency of pump and dispensing were analyzed to clarify the relationship between the peristaltic pump and ratchet speed, where the number of ratchet teeth was determined to be 4. As such, the matching was realized between the peristaltic pump and ratchet spotting glue. The ratchet profile was also designed, according to the spotting glue motion. A theoretical analysis was made on the movement of seeds in the seed guiding tube. It was found that the aggregation effect of seeds on the paper tape relied on the length and cross-sectional angle of the seed guiding tube, as well as the rotation speed of the socket wheel. The seed guiding tube was then optimized for the optimal structural parameters. A Box_Behnken test was also carried out, where the length and cross-sectional angle of the seed guiding tube, while the rotation speed of the socket wheel was taken as the test factors, whereas, the percentage of seeds in the effective area on the paper tape was taken as the test index. The results showed that the percentage of seeds in the effective area on the paper tape was 57.23%, when the length of the seed guiding tube was 56 mm, the section angle was 35°, and the rotation speed of the seed metering wheel was 30 r/min. An adhesion test was also performed on the Shanghai Qing 605 seeds with a diameter of 1.5-2.0 mm. The test factors were then selected as the roller angle of the peristaltic pump and the mass ratio of pregelatinized starch to water. An optimal combination of parameters was achieved, including the size of the glue point, and the mass ratio of pregelatinized starch to water. Once the roller rotation angle was 10° and the mass ratio of pre-gelatinized starch to water was 1:6, the single seed rate of glue point adhesion to seeds reached 97.4%. The adaptability test was also carried out on the whole machine on the working performance of different varieties of small seed vegetables. It was found that the single seed rates of Shanghai Qing 605 and Siji Chinese cabbage seeds were greater than 95% under the working speed of 0.5-1.5 m/s, whereas, the coefficient of variation of plant spacing was less than 10%, fully meeting the requirements of precision sowing indicators that specified in the standard NY/T1143-2006. Therefore, the single seed rate and the working efficiency of the improved seeder increased by 3.53%, and 50% than before. [ABSTRACT FROM AUTHOR]