design and development of a drum type saffron corm sizing-machine

iran, with more than 90% of world production, is known as the main saffron producer. this plant is sterile and the saffron proliferation is possible only via cultivation of corms. one of the most problems in saffron cultivation is the yield reduction due to planting of small corms. in this research, a new saffron corm-grading machine is introduced. the machine includes a rotating drum, which is made of adjustable longitudinal rods. the small and unusable corms are separated via passing them between gaps of the rods. the physical properties of corms were determined and used to calculate gaps dimensions. the effective parameters in machine performance were: rotating drum speed (n), gradient of drum (α), and feeding rate (q). the response surface methodology (rsm) was used to optimize the parameters. an acceptable sizing accuracy of 79% were obtained at n= 33.85 rpm, α=4º, and q=340.1 kg/h as optimum conditions.