Design and Efficiency of a String Hulling Machine for Buckwheat

An important task of food engineering, namely grain processing and the pro-duction of cereals and fodder, is the improvement of hulling equipment and the creation of complex technological lines for the processing of the original crops is gaining particular relevance. The reason for this is the need to carry out several preparatory stages, and, as a result, the use of additional equipment. To solve this problem, a string hulling device had been developed, the use of which allows reducing the number of operations due to the exclusion of preliminary sorting into fractions and wet-heat treatment. These operations are required by other hulling machines included in the technological lines of buckwheat processing. The structural scheme of the string hulling device had been developed and the principle of the shell removal operation had been substantiated. Theoretical studies had been carried out by the methods of analysis and synthesis of the mechanics of destruction and systematic analysis of the process of buckwheat hulling by impact. Experimental studies had been carried out using a laboratory string hulling device. The conducted analytical studies made it possible to determine the regularity between the physical and mechanical characteristics of buckwheat and the critical linear impact speed necessary for the destruction of the shell. This allows deter-mining the frequency of rotation of the string at which the destruction of the shell will occur while preserving the integrity of the core. Experimental studies made it possible to determine the quality of buckwheat hulling by determining the coefficient of integrity of the kernel and the coefficient of hulling. It has been determined that the ranges of the rotation frequency of the strings required to ensure a high degree of the buckwheat hulling technological process efficiency are within 15.8-16.9 s⁻¹.