Análise dos coeficientes de atrito estático e dinâmico de grãos de café com pergaminho, determinados em diferentes equipamentos, teores de água e materiais de parede

Abstract

The objective of this work was to determine and to evaluate the physical properties coefficients of static and dynamic friction with the wall of the grains of coffee with parchment of two species and the behavior of this product, in text function different of moisture content and materials of wall, as well as, to compare the results of these properties, determined for simpler experimental equipment and of easy construction and operation, with the equipment of shear of Jenike, used as standard for the main international norms of silos. Such analyses are of basic importance for the calculation of flow and pressures in silos, and indispensable to a economic and safe project structural of equipment and silos, aiming at always to the maintenance of the product quality. With the gotten results, it could be concluded, that for both studied varieties of coffee, the coefficients of static and dynamic friction had increased linearly with the increment of the moisture content, independently of the wall material; the use of the considered equipment is not recommended alternative; e the analyzed coefficients more are influenced by the harshness of the material of wall of that for the moisture content of the product.