Justification of parameters of impact-spreading finger shaft for grinder-mixer-dryer using the example of eggshells

Abstract

The object of the study is to determine the critical impact speed during shell destruction, study crack formation in the shell, and grind the shell. When operating a grinder-mixer-dryer, problems arise such as determining the speed of impact on the shell depending on the height of its fall, the lack of ability to determine the speed of shell fall from certain heights, which complicates planning the operation of the finger shaft. As a result of research, it was found that an auger with knives crushes and moves feed raw materials, and the impact-spreading shaft ensures partial grinding of fragile raw materials and intensive processes of mixing and drying wet feed with uniform filling of the installation hopper. The appearance of cracks on the shell when it falls from a height of 0.15 m has been experimentally recorded. Therefore, this speed of impact of the shell on a metal surface is the critical peripheral speed of the impact-spreading shaft, which ensures partial crushing of the shell. As a result of theoretical studies, an analytical expression was obtained that provides the determination of the shell impact speed depending on the height of its fall. The value of the critical peripheral speed of the fingers of the impact-spreading shaft is determined to be 1.66 m/s. The experimental results showed the effective occurrence of grinding, mixing and drying processes. Moreover, within 15 minutes of operation of the installation, the wet shell was crushed in accordance with the requirements. The uniformity reached up to 90 % within 4 to 6 minutes of its operation, and drying proceeded at a rate of 26.54 % per hour. All this proves the effectiveness of the processes of grinding, mixing and drying wet food, and also confirms the reliability of theoretical research