Abstract

AGUDELO GOMEZ, Diego et al. DEVELOPMENT OF A SEPARATOR IN THE COFFEE HARD OBJECTS FROM THE VIBRATIONS PRODUCED IN THIN PLATES. Rev. Fac. Nac. Agron. Medellín [online]. 2008, vol.61, n.2, pp.4686-4700. ISSN 0304-2847.

Electromechanical experimental models of an electronic separator of hard objects, denominated PESELOD (pescador electrónico de objetos duros, Spanish) were designed and constructed in Cenicafé to protect the coffee processing machines. The module, located before the pulping machine, includes a feeder, a vibrant body (thin plate or metallic cone), a gate, a hard objects container and a circuit for both hard objects detection and automatic separation. Its principle of operation is based on the difference of amplitude and frequency of the vibrations produced by impact of coffee fruits and hard objects against a vibrant body. The historical analysis was made in the spectrums of the accelerations that were induced on different materials, thicknesses and boundary conditions. The device worked better with steel plates, 2.5 mm thick, simply supported. The model presented effectiveness greater than 80% and yields between 300 and 2.000 kg h^-1 of coffee fruits. To improve their operability related to dirty plates, another model was constructed with a truncated cone vibrant body.

Keywords : Hard stones; plates; vibrations; signal processing; FFT.

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