논문 상세보기
pp.293-302
본 연구에서는 입경·비중 겸용 밭작물 곡물 선별기 개발을 위한 전 단계로서, 밭작물 곡물의 완전립과 불량립의 기하학적, 공기역학적, 마찰 특성을 측정하고, 선별기 설계에 적용하기 위한 선별 요인을 분석하였다. 측정된 곡물의 기하학적 특성 결과(길이, 폭, 두께)를 이용하여 스크린의 치수와 형상을 결정하여 선별기를 제작하여 선별시험을 한 결과 선별효율은 콩의 경우 94.7%, 커피는 92.0%, 아몬드는 74.5%, 옥수수는 90.0%로 나타났다. 측정된 곡물의 마찰 특성 결과를 이용한 고무벨트 선별 시험 결과 콩의 경우 벨트 속도 0.5 m/s, 벨트 각도 5˚ 일 때 선별효율이 88.2%로 가장 높게 나타났다. 측정된 곡물의 공기역학적 특성 결과, 종말속도는 콩의 경우 4.4∼6.0 m/s, 커피는 3.2∼4.4 m/s, 아몬드는 3.5∼5.1 m/s, 옥수수는 4.7∼6.0 m/s의 범위로 나타났다.
This study was implemented to develop a separator based on particle size, shape and gravity for upland cereal crops as a preliminary research. The geometric, friction and aerodynamic characteristics of perfect and imperfect grains were tested, and separation factors were analyzed for separator design. The geometric properties of the measured cereals showed that 8.20 mm long, 7.49 mm wide and 6.24 mm thick for soybean, 9.57 mm long, 7.30 mm wide and 3.93 mm thick for coffee 21.77 mm long, 12.04 mm wide, and 7.55 mm thick for almond, and 8.12 mm long, 7.80 mm wide and 5.64 mm thick for corn. The size and shape of the screen for the separator were determined by these factors. The separation efficiency with the separator was 94.7%, 92.0%, 74.5% and 90.0% for soybean, coffee, almond and corn, respectively. Friction properties of the cereals were tested with different velocities and angles in a rubber belt. The measured friction coefficients were 0.432 for perfect-shaped soybean, 0.371 for round-surfaced coffee, 0.356 for perfect-shaped almond, and 0.665 for round-surfaced corn. The friction coefficients of the imperfect grain showed large differences in the rubber belt. In the separation efficient test, soybean showed the highest efficiency as 88.2% at a belt velocity of 0.5m/s and angle of 5°. Aerodynamic characteristics for the cereals were tested, and the results showed that the terminal velocity was 4.4 to 6.0 m/s for soybean, 3.2 to 4.4 m/s for coffee, 3.5 to 5.1 m/s for almond, and 4.7 to 6.0 m/s for corn. With the analyzed results, it was possible to determine hole size and shape for size-based selection, friction materials, conveying velocity and angle for shape-based selection, and air velocity for gravity separation.
