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      PROCESSING EQUIPMENTS 
        The equipment involved in cleaning , 
         
        Air-Screen cleaner cum grader 
           
          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. 
         
             
         
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