Some paramters affecting cleaning and grading of fenugreek seeds [electronic resource].
بعض العوامل المؤثرة على تنظيف وتدريج حبوب الحلبة.
- p.535-554.
Includes references.
The purpose of this study was to develop and evaluate rotating screen separator for grading and cleaning fenugreek seeds. A horizontal cylindrical screen unit was designed, constructed in special workshop, and used to grade fenugreek seeds and to separate trashy materials from it. The horizontal cylindrical screen unit had dimensions of 60-cm long and 10-cm diameter, and had gradual holes with ability to change its slope. It was divided into three gradual scales of sieves, and it was operated by electric motor (0.25 kW) with different tires and belts for changing its angular velocity. Under the horizontal cylindrical screen unit, there was a wooden collection box, which is divided into three parts, same as the screens. Physical and Mechanical properties of fenugreek seeds were determined. A theoretical analysis was made to determine the critical velocity for seeds separation, and test it experimentally. The obtained results indicated that the average moisture content and bulk density of fenugreek seeds used in this study were 13.6% ( w.b.) and 0.52 g/cm3, respectively. The average length, width and thickness of fenugreek seeds were 4.2 mm, 2.8 mm and 1.8 mm, respectively. The average values of seed volume (V), spherical percentage (Sp), geometric diameter (Dg), arithmetic diameter (Da), flat surface area (Af) and transverse surface area (Ath) were 11.8 mm3, 65.86%, 2.77 mm, 4.26 mm, 11.76 mm2, 3.96 mm2, respectively. The friction angle between seeds and stainless steel, metal and wood surfaces was 22°, 30° and 35°, respectively. The average seeds terminal velocity and angle of repose was 35 m/s and 33°, respectively. The machine efficiency for separating fenugreek seeds increased by increasing the screen speed and decreasing the feeding rate. Zero slope of the horizontal sieve gave higher machine separating efficiency of fenugreek seeds at conditions mentioned previously.