Abstract: Seed materials are presorted by directing a stream of air across a cascade of the materials into heavy, mixed and light fractions and only the mixed fraction is then subjected to the usual gamut and further sorting and classifying operations. The heavy fraction consists predominantly of good seed which does not require such futher processing.

Abstract: The invention relates to an equipment for the uniform dosage, dispersion and application of protective substances with liquid formulas, particularly seed-dressing means, on seeds under the action of compressed air, with a mixing drum having a seed inlet and a feeding duct for the protective substances, wherein a pipe for liquids (4) serving for the supply of protective substances originating from the dosage pump (3) and abutting in the mixing drum (1) is connected with an equalizing container or pipe (5) for the suction of secondary air, wherein a compressed-air duct (10) abutting in the mixing drum (1) is provided, in the outlet of the former the outlet of the pipe for liquids (4) being concentrically located and wherein a baffle plate (7) is mounted opposite to the exit of the pipe for liquids (4).