Effectiveness of the pneumatic separation of Norway spruce Picea abies (L.) Karst seeds

The paper presents the theoretical basis for the pneumatic separation of Norway spruce seeds along with the results of investigations into the effectiveness of separation conducted in a pneumatic separator with a vertical air column. Such a separator was designed and produced at the Department of Forest Works Mechanization of the Agricultural University of Kraków. The device makes it possible to separate a mixture into three fractions based on the differences in critical velocities. The variation in density among different seed fractions is about two times lower than the variation in seed mass. This result supports the suggestion that omitting the size calibration of seeds before their pneumatic separation could lead to the dominance of seed density as a distinguishing feature.