Designing of an Equipment for Mechanical Drying of Coffee and its Evaluation Begin ning with the Construction of a 1:5 Model Scale Diseño de un equipo para secado mecánico de café y su evaluación a partir de la construcción de un modelo a escala 1:5

Abstract

In order to get better the process of drying the coffee, it was designed mechanic equipment like a silo which has some advantages such as: less necessity of space to dry; it is dismantled, it reduce the labor, drying duration and it keeps the product quality. The silo is constituted by two drying chambers and the airfl ow can go through them carrying out drying and pre - drying depending on the flow direction used ( gates system) which let homogeneity in the final humidity of the  grain. Moreover, it presents a practical mechanism to download the drying grains  using an inclination in the drying beds of 38º. Themeasurement of the drying silo obtained was: total capacity = 2340 Kg., air volume = 4540.61 CFM, pressure loss ( Δ P) = 2.066 inches. w.g., motor  single - phase electrical of  2.5 HP. The construction and evaluation of a prototype to scale 1:5 of the drying silo  serves as a parameter to get the following information about the kinetics of the drying: initial moisture (50.61%), final moisture (10.09%), average temperature of  drying airflow (46.67 ºC), volume of flow (Q = 0.08m³/s.) and time of drying (28 hours). Besides, it allowed to corroborate the operation conditions of the system.