Question

5. a. (i) “Describe the single most important piece of equipment for cleaning seeds.” (II) Suggest principles of adjustments that might apply to almost any piece of seed cleaning equipment.” b. “Do you believe that most seed conditioners only attempt to condition to those quality levels that will meet minimum acceptance levels of seed trade?

Answer 1

i. gravity separator is used for cleaning and upgrading seeds. It is normally used only after air screen machine have been used to elliminate most chaffs, stems and off-sized contamination.

ii. The air-screen machine is the basic cleaner in most seed processing plants. Almost all seed must be cleaned by air-screen cleaner before specific specifications can be attempted. Machine size varies from small, two-screen farm models to large industrial cleaners with 7-8 screens. Two-screen models are used on farms, in breeder and foundation seed programs and by experiment stations for processing small quantities of seed. In most machines separations are made on the basis of differences in only one physical characteristic.

The air-screen machine, however, effects separations on the basis of differences in size and weight of seeds. This enables the air-screen machine to use three cleaning elements: aspirator, in which light material is removed from the seed mass; scalper in which good seed are dropped through screen openings; but larger material is carried over the screen into a separate spout; and grader, in which good crop seed ride over screen openings, while smaller particles drop through.

b.Before the seed can be sold for planting through regular trade channels, enough of the undesirable materials must be removed to
enable the seed to meet quality standards demanded py the farmers and
required by law. In addition to removal of undesirable materials, seed
often need to be treated with a fungicide before marketing. Preparation of seed for market, therefore, involves a series of mechan ical operations designed to remove undesirable materials, apply a chemical treatment as
needed, and to package the seed in some container suitable for distri-
bution and marketing . These various operations/processes are termed
seed conditioning, and encompasses, more specifically, operations such
as receiving, pre-conditioning (debearding, hulling, partial cleaning,
etc.), conveying, cleaning, sizing, up-grading, treating, and packaging. Seed conditioning is an important element in the business of providing
an ample supply of high quality seed for the farms , gardens, recreational
areas , pasture lands, and so on, of the world.