Principles of Cleaning Seeds
In this cleaning process, the separation of undesirable material, namely , inert matter, weed seeds, other crop seeds, light and chaffy seeds, off-size, damaged or deteriorated seed from desirable material is done on the basis of differences in physical properties of desirable seed and undesirable matter. The principal physical differences found in seeds are seed size (length, width and thickness) , density , shape , surface texture, colour , affinity for liquids, and seed conductivity. If the differences between desirable and undesirable material in regard to any of these properties exist, separation of undesirable material could be done with the help of suitable machine/ machines designed for the purpose.
Seeds of different species and inert matter widely differ in regard to the physical properties. Length, width, shape , weight , and surface texture differences are quite common in crop species and forms the basis of seed cleaning operations.