COEFFICIENT OF EXPLOSION OF GRAPE OIL REPAS IN RESPECT OF VARIETY, CONTENT OF HUMIDITY AND SURFACE

Knowing the coefficient of friction of bio material is important in determining the angle of the grain elevator elevator when designing combines, as well as the angles of gravity tables and pipes in seed finishing. The basic characteristic of biological materials, or seeds of agricultural crops, is that they differ in their physical and morphological characteristics. Therefore, the friction depends on: the types of plants, variety, shape, dimensions and seed content, the humidity of the seed, the intensity of the normal force on the substrate and the roughness of the substrate. The paper presents the results of the study of the influence of individual factors (varieties, water content of the grain and the type of substrate) and their interactions on the grain friction coefficient. The domestic varieties that are grown in Serbia are selected for testing the fruiting grain fruity: Banadanka, Jasna and Slavica. The experimental measurement of the static coefficient of grain slip friction was done using the level of the mechanical device Tribometr. Plastic, plywood, galvanized, steel, aluminum and stainless steel sheet are made for the experiment purposes. Research was carried out with different water content in grains: 6%, 11%, 16% and 24%. The variety Banadanka had a lower friction coefficient compared to Jasna and Slavica varieties on all substrates and with all the water content of the grain. It was found that with the increase of water content in the grain, a significant increase in the friction coefficient of the grains of the tested varieties on all substrates was achieved. The highest friction coefficient for all water content of the grains of the tested varieties was on the base of the plywood board, and the smallest on the base of stainless steel sheet.