Authors: B. A. Adewumi, O. C. Ademosun, A. S. Ogunlowo
Agricultural Engineering International: the CIGR Ejournal. Manuscript FP 06 020. Vol. VIII. October, 2006
Abstract
A thresher-cleaner developed at the Federal University of Technology, Akure, Nigeria was used to study the distribution and spread of the threshed cowpea in a cross flow system.
Podded cowpea was subjected to insect infestation before threshing to ensure that the grains are with heterogeneous and varied aerodynamic characteristics. Majority of the pods were collected at the exit end of the thresher unit while the grains and a few pods obtained at the discharge end of the thresher unit were channeled into the cleaning chamber. Pod moisture content (PMC) of 14.0%, 18.0%, and 22.0% equivalent to grain moisture content (GMC) of 15.3%, 17.2%, and 18.8% respectively; fan speed of 900 rpm and 1500 rpm and fan angle of inclination of 90o, 105o and 120o to the vertical plane were used for the study.
The spread patterns of the materials recovered in the cleaning chamber were analyzed and evaluated by plotting the percentage frequency distribution curve using the S-Plus and Harvard Professional 3.0 soft wares. The model fitting was done using ordinary least square (OLS) method with a simple program. The effect of pod and grain moisture content, fan speed and the angle of inclination of the fan were observed and studied as they affect the material distribution in the cleaning chamber.
Keywords: Cowpea, Grain size, fractionation, Separation, Material distribution