DETERMINING OPTIMAL KINEMATIC PARAMETERS OF A SIEVE MILL USED FOR SEPA-RATING SELECTION SEED SAMPLES

Today, post-harvest processing of breeding material requires using a screen seed cleaner that should be adequate in performance and comply with all the requirements for plant-breeding machines. For the research, use was made of a model bench of a screen seed cleaner with pre-determined kinematic parameters of the scree shoe and the inclination angles of screens. The experiments were conducted for five variants of the vibration amplitude of a screen shoe (7, 10, 14, 18 and 22 mm), with a change in the frequency of its vibration frequency from 169 to 470 min‑1. At the same time, the kinematic screen index varied within 6.9…19.3 m/sec2. The same experiments were carried out at two inclination angles of the screen shoe –
6 and 9°. It has been shown that an increase in the kinematic indicator of screens leads to decreased clogging of screen holes. The optimal values of the kinematic indicator of screens with oblong holes, depending on the vibration amplitude, are within 11.0…15.0 m/sec2. The extraction coefficient of minor impurities in this case varies within 84.6…89.6%. With a large inclination angle of the screens (9°), the penetration rate of the upper screen (with round holes) is 3…10 times higher, and the lower screen (with rectangular holes) is clogged approximately 2 times more intensively than at an inclination angle of 6°. The authors have determined that for a screen seed cleaner to operate at the modes ensuring optimal processing of both small seeds and grain crops, the vibration amplitude of a screen shoe should equal 9 mm, and its vibration frequency should
range between 350 and 450 min‑1 at an inclination angle of screens amounting to 7°.