Nowadays, coffee agribusiness represents the second largest commodity in the world. Storing coffee beans in silos, instead of in bags or big-bags, has been an increase tendency. Several factors justify that tendency: cheaper and safer transport by container trucks, lower cost of containers for export shipment, less labor in handling, greater safety against fire, faster filling and discharge, and elimination of extra expenses due to values not aggregated to the product.
Aiming at an economic and rational solution for storing coffee beans this paper presents an alternative design: a multi-cell silo group composed of reinforced masonry rectangular cells coupled two by two in width, and a variable number of cells in length according to the volume of desired storage. Such symmetrical system benefits the loading and the unloading operations, and guarantees the continuity between the receipt flow and the shipment flow.
The silo bottom is designed as a double pyramidal central opening hopper. That shape reduces the height of the hopper in the cell, and consequently reduces the total height of the silo lowering the cost of the building. The hoppers are built in precast-concrete trussed panels. Cells and hoppers are supported on concrete beams and columns. The thermal insulation needed to preserve the quality of the stored coffee beans is obtained by using galvanized steel trapezoid tiles for the roof as well as for the lateral closure. The roof structure consists of a precastconcrete slab that restrains the silo structure. An example is presented and the feasibility of the alternative design is discussed.
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