Design of Vertical Rotor Metering Plate for Precision Seeding of Okra: Incorporating Physical and Engineering Properties

Abstract

An investigation was conducted with the aim of examining the physical and engineering properties of okra seeds. The physical and frictional characteristics of okra seeds play a crucial role in the design of a seeder, influencing decisions regarding cell size, shape, metering disc thickness, and material, as well as the inclination of the seed hopper. The study aimed to determine these properties of okra seeds. The primary findings indicated that the typical values for the length, width, and thickness of the seeds were 5.58 mm, 4.61 mm, and 4.18 mm, respectively. The maximum width and length of the seeds served as the basis for the design of the cell diameters and thickness of the seed metering rotor. The okra variety “VNR-Deepika” exhibited a geometric mean diameter of 4.79 mm, with sphericity and roundness values of 85.2% and 82.85%, respectively. The roundness and sphericity of the seed affected its ability to move through the seeder's components. Test weight, bulk density, true density, volume, porosity, angle of repose, and coefficient of static friction were measured as 57.06 g, 0.56 g cm-3, 1.12 g cm-3, 111.46 mm-3, 50.22%, 25.97° and 0.42, respectively. The depth of the vertical rotor cells was established at 6.25 mm, slightly exceeding the average seed length to ensure singular seed dispensing. Simultaneously, the width of each cell was calculated to be 6.98 mm, offering adequate space for accommodating one seed per cell. Featuring 14 cells positioned around the vertical rotor's circumference, the seed metering rotor was designed to have an 85 mm diameter.