Destruction of grain by working bodies of the impact cutter

Abstract

The article discusses the intensity of grain destruction from the point of view of process optimization, analysis of the results of experimental studies on grain refining with an impact grinder, taking into account the optimal design parameters. The interaction of grain with rotor impact elements and stator chops was investigated, analytical calculations of structural elements that directly affect the intensity of grain destruction were carried out. The grinding process in impact grinders should create conditions for the destruction of grain, under which the material is repeatedly subjected to mechanical loading by the working bodies, in turn, this helps to reduce the time for grinding and reduces energy consumption.

When the grain interacts with the impact elements of the rotor, partial destruction occurs, and later, under the action of the centrifugal force, the grain falls on the stator reflecting plate, where the process of intensive destruction takes place. In this case, the grain as a result of the impact is not completely destroyed, and the energy is expended, the grinding process may not be completed. The grinding process was studied without taking into account the chop plates in the form of structural elements of the stator. The design of a percussion grinder has been developed and proposed (patent for a useful model UA No. 115612 U., B02С 13/2, 25 04. 2017, Bul. No. 8), which allows to significantly increase the degree of grinding due to a significant increase in "frontal" impact.

The principle of operation of this design is as follows - when the rotor rotates, the crushed material is carried away by the impact elements and directed to the chop plates fixed between the rotor and stator. This arrangement of the baffle plates ensures the movement of material perpendicular to their area. That is, there is a "frontal" impact of the grain in relation to the chops. With this arrangement of the reflective plate, the force of destruction of the grain is greatest, and, accordingly, the intensity of destruction will be maximum.

Analyzing the results of the study, we come to the conclusion that the greatest intensity of grain destruction by a percussion grinder with installed chops occurs at the angle of the reflective plate position in relation to the direction of grain movement (α = 90º). Also, the grain mass and the linear velocity of the striking element will have a positive effect on the intensity of destruction. At α = 90º "frontal" impact takes place. With an increase or decrease in the angle α (more or less than 90º), the intensity of destruction decreases.