String sieve: design concept and parameters

This paper presents the design concept and the parameters of a new device for cleaning and-or sorting seeds and grain produced in a conventional farm. The discussed device is a string sieve where the groove between adjacent strings is minimal at the beginning of the screen and increases towards the end of the screen. The proposed sieve poses an alternative to a screen separator comprising a set of differently-sized mesh screens with longitudinal openings. In view of the average size of farm-produced seeds, the width of the separating groove should be set at 1mm at the beginning of the screen and 11 mm at the end of the screen. In sieves not designed for grading large seeds or vetch seeds, the width of the separating groove can be set at 1 mm and 5 mm, respectively.