Influence of Screw Conveyors on the Grain Quality Indicators of Cereals

Abstract

The efficiency and quality of the screw conveyor equipment depends on a number of parameters including the density of the load, the step and diameter of the screw its speed (or angular velocity) the gap between the screw and the body. As the rotational speed increases the helical surface moves toward the grain material begins to throw it back into the loading device thereby worsening the capture process. The greater the angular velocity of the working body the greater the impact on the load (the stronger it is thrown off by the helical surface). The performance of the screw feeder begins to decrease and damage to the grain material increases substantially. A grain particle moving along the axis of the helical working organ performs a complex sliding motion along the friction surfaces by scrolling around its own center of mass. This continues until the conditions of pinching the particle in the gap arise due to the wear of the working surface of the screw, the erosion of the front angle of interaction with the grain mass and the emergence of a germination gap. In investigating the damage to the seed material it was established that the use of a conveyor, with the possibility of regulating the clearance between the screw and the body in rationally permissible limits allows reducing the damage of grain to the screw working organ to 0.3 % while preserving the maximum productivity of the process. It has been established that the optimal parameters of the horizontal screw conveyor devices in terms of damage as the main factor limiting the requirements for damage to the seed material is the speed of the working body – 100 - 200 rpm in the gap between the screw and the housing 1 - 2 mm. After moving the material with screw conveyors the largest number of wheat grains with traumatized shell of grain and endosperm and damaged endosperm shell were detected which significantly reduced the quality of seeds and yield.