The mixtures which compose the mass of seeds have different characteristics, this thing leading to a non homogenous mass of seeds, from the point of view of quality. By this reason, for the sorting in good conditions of the mass of seeds, it must be analyzed the physical-mechanical characteristics of seeds and impurities which compose the mass to be separated, in order to establish the technology of separation of impurities. The main characteristics which decide the sorting methods of seeds are: dimensions of seeds and impurities, shapes, state of surfaces, mechanical strength, elasticity, specific weight, electric properties, colors of seeds and impurities. The technological and commercial value of the mass of seeds is diminished by the non uniformity as size, shape and color of seeds. The sorting of the mass of seeds is made in order to increase the purity and realizing of homogenous masses of seeds from the point of view of the seed uniformity. As a function of separation simplify by mechanical methods, the impurities are classified as easily and difficultly separable. The separation of seeds in fractions, as a function of dimensions (length, thickness, width), comprised between some limits, is called calibration. The indented cylinder is used for sorting by length all cereals seeds such as wheat, oats, barley, sunflower, sugar beet seeds, alfalfa and for separating unwanted long or short product impurities. In order to calculate and design the sorting machines, it is necessary to establish the laws of motion of the seeds in the indented cylinders. The study of the seed movement in the indented cylinder was realized using the dynamic model of material particle. The process of separation of seeds with the indented cylinder, respectively the efficiency of seed separation, is influenced by the cylinder construction (diameter, dimensions of pockets), cylinder inclination, speed of rotation and by the character of the relative motion of seeds in the indented cylinder, respectively by the kinematical index of cylinder. The design and construction of the seed sorting machines is influenced by the structure and physical-mechanical properties of seeds.

indented cylinder, particle, relative motion, force, kinematical index

sciences soil

Presentation: oral