Substantiation of rational design parameters of variable pitch screw of an extruder

Abstract

The analysis of effectiveness of methods of feed material (extrudate) preparation for feeding showed that the thermal method of its processing with the use of the KMZ-2 extruder is of most practical and academic interest. The studies carried out by V.V. Novikov showed that in the process of its formation the extrudate moves throughout the length of working chamber in the space between the screw flights and the inner surface of body, due to this the obtained mixture is heated and compacted. Based on the theoretical researches carried out by V.Yu. Frolov, it was found that the screw should have a variable pitch gradually decreasing with the movement of the processed feed material along its axis. During its movement the processed feed material is compacted and reaches the condition that allows to take the required shape in accordance with process requirements. Determination of rational parameters of variable pitch screw of extruder in areas for loading and pressing is a very important task on both practical and theoretical grounds. The aim of the article is to determine the rational design parameters of variable pitch screw of extruder in areas for loading and pressing of processed feed material on the basis of sunflower cake. At the initial stage, the design parameters of variable pitch screw of extruder in the area for loading of processed feed material were considered. At the next stage, the process of its compaction and compressing by means of screw was considered. As a result of theoretical researches of variable pitch screw of the KMZ-2 extruder, it was found that the density increasing of the processed feed material on the basis of sunflower cake is proportional to the decreasing of pitch of screw flight. The density of processed feed material depends on its physical and mechanical properties.