The aim of this investigation is to improve seed cleaner for better clean and grade by using physical and mechanical properties of flax seeds (Sakha 2 -variety). The developed machine was constructed and tested at a private workshop in Kalubia Governorate to clean and grad flax seeds. The performance of the cleaning and grading machine was carried out to investigate some engineering parameters such as: three different feed rates of 1000, 1200 and 1400 kg/h., four different mesh hole sizes of 0.5, 1.1, 2.5 and 3.0 mm and four different vibration frequencies of 40, 70, 100 and 130 Hz. physical and mechanical properties of fax seeds under study, purity and grading efficiency were studied to evaluate the performance of developed cleaning and grading machine.
The main results in the present study can be summarized as follows:-
- Physical properties of flax seeds: length (L), width (W), and thickness (T) were 4.38, 2.2, and 0.72 mm, respectively , volume (V) 3.631 mm3, geometric diameter (Dg) 1.906 mm, arithmetic diameter (Da) 2.44 mm, percentage of sphericity (S) 43.52 %, bulk density (Bd) 0.640 kg/m3, flat surface area (Af)7.56 mm2 transverse surface area (At) 1.24mm2 mass of 1000-seeds (Km)10 g and optimum moisture content (M.C) of 12.5 % for flax seeds .
- Mechanical properties of flax seeds: the friction angle (Ψ) between stainless, metal and wood surface and flax seeds was 22, 34, and 40 degree, respectively, coefficient of friction for stainless, metal, and wood surface was 0.404, 0.675, and 0.839, respectively, the angle of repose (θ)was 30 degree, the terminal velocity (Tv) value to suspended flax grain (Sakha 2 – variety) was 22 m/s. and hardness of flax seeds was11.02 N.
_ The higher seed purity was 99.33 % and higher grading efficiency was 99.69 % were reached using vibration frequency of 130 Hz, mesh hole size of 3 mm, feed rate of 1400 kg/h and moisture content of 12.5 %.