SUBSTANTIATION OF THE BASIC PARAMETERS OF THE SCREW EXPANDER FOR PROCESSING HIGH PROTEIN CROPS

Abstract

The article provides a way to increase the productivity of a screw press variety – the expander. The use of an expander makes it possible to produce compound feed in the form of non-solid whole meals, which has a beneficial effect on the process of digestibility by animals. To correct the existing drawback of the expander – the reverse extrusion of the working mass through the gap between the screw and the body, the authors proposed a combined profile of the screw spiral groove: the left lateral (pushing) surface of the groove has the shape of a semicircle, and the right lateral surface has a semicircular shape in the lower part, and in the middle and upper – the shape of a sloping straight line. Theoretical studies have shown that this profile contributes to the appearance of a difference in lateral pressure forces from the side of boundary particles on the bulk of the material, in contrast to screws with a standard spiral groove made in the form of a triangle, trapezium, or semicircle. In turn, the uneven distribution of lateral pressure will prevent backward extrusion of the processed material through the gap between the auger and the body, thereby increasing the performance of the expander. Theoretical dependencies have been obtained that allow, on the basis of the basic geometric parameters of the screw, to describe geometrically the configuration of the screw of the proposed design for its subsequent manufacture.

Keywords

• expander
• pressing
• extrusion
• screw
• feed preparation
• processing
• extruder