Trieur is used for selecting the round, and long shaped unwanted subtances, which are in the prain, at the factories grinding cereals.The rollers, pressed on the sheet, with different diameters and the depth of which are staded according the quality and the kinds of wheat to be cleaned are driven by an motor redactor. The strange grains/ materials are collected with the help of spectral collectors anda re taken at the exit of the machine by the screw, which is at the center of the rolers. The separated grains are sorted throught the control trieur in order to re-select the grains mixed in the unwanted substances