Inventor: Assist. Prof. Dr. Kareem Hassan Ali, Assist. Prof. Dr. Fathi Abdul Sahib Al-Shamaa/Department of Mechanical Engineering, College of Engineering, University of Baghdad
Abstract
The whitening process is a change of grain rice from brown into white that acceptable to consumption of human. There are three important factors that taken into consideration which is an effect on the process of rice whitening. These factors are a length of the main shaft that carried stone, a diameter of the sieve and the rotation speed of the main shaft. These three factors are inserting into the design of a new sieve by centrifugal force, also there is two main force are effective in whitening rice which are results from the bending force of the centrifugal force and shear force from the friction force between rice and sieve. Done the shape and number of holes in the new design of the sieve have changed for a purpose to increase a surface area of whitening. The diameter of a new sieve holes is 1 mm, a distance between two-hole 0.5 mm and these holes are sharp inward to about 0.01 mm. Result a ratio is obtaining between bending force and shear force 0.5% this percentage is the basis for the manufacture of sieves of whitening. when the increase of this ratio will cause grinding rice and when decreased in this rate will cause a fracture in rice. In addition, the new design gave a higher whitening rate for the rice than the old design, which is 32.9% during rotational speed 500 rpm this speed is not reached by any researcher, the broken ratio ranges from 9-12%. It also extends the life of the mechanical parts of the machine. Therefore, find the experimental work result is identical with theoretical results, where of done the strain measurement by stabilizing the strain gauge at four angles (0, 10, 45 and 90). As well as, the temperature will be increased through a new sieve by 10 c.