Experimental data of the ear threshing process in a pneumatic device

Introduction. The current problem is the high level of grain injuries during the threshing process. Therefore it is necessary to develop the gentle methods for separating grains from ears. These methods shall exclude direct shock influence of operative parts of the threshing devices on cereal grains. The objective of research is to study the process of the wheatear threshing in the pneumatic device and to estimate the influence of device settings on cereal grain separation and damage. Materials and Methods. The experimental apparatus is a pneumatic threshing device. The threshing is carried out in case of the interaction of an ear and concave under the influence of the alternating high and low pressure of the airflow generating by the rotor's blades. Separation is carried out by means of deriving light-load tailings into the reduced pressure chamber. Results. The grain damage decreases in reducing the speed of rotor blades motion and consequently the speed of ears motion in the threshing unit. Germ damage and grain breakage decrease almost to zero at a minimum blade motion speed of 13.5 mps. The range of blade speed between 13.5 and 20 mps is the most favorable for the pneumatic grain threshing in terms of the germ damage. The pneumatic threshing on the experimental device results in effective assorting of grains and light-load tailings of ears. Discussion and Conclusion. Process of the wheat ears pneumatic threshing has satisfactory results. The pneumatic threshing reduces grain endosperm damage by 10...12%. Grain germ damage decreases by 5%, practically to zero. Crushing of grain at rotor blades minimum speed is no more than 0.5%. Comparison of shares of the damaged and crushed grains when using the pneumatic threshing with shares of the damaged grains when using the traditional combine threshing has showed that the offered method of the threshing provides a reduction in grain damage.