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Author: Suma Nair × End date: 1999 × Start date: 1996 × Thesis Type: M.Tech ×
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    ThesisItemOpen Access
    Development of a power operated black pepper thresher
    (Department of Farm Power Machinery and Energy, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 1998) Suma Nair; KAU; Jippu Jacob
    A power operated black pepper thresher comprising mainly of a threshing drum and a concave; both lined with thermofoam, was developed. It was driven by a O.S-hp, 3-phase, variable speed motor. Pepper spikes were fed into the thresher and the threshed material from all the outlets were collected and separated into berries, damaged berries, unthreshed spikes, partially threshed spikes, and partially threshed spikes with unthreshed berries. The weights of all the fractions were recorded. The values of the threshing efficiency, the percentage of damaged berries, and the capacity were calculated. A three-factor factorial experiment was conducted taking the feed rate, the peripheral velocity, and the contact length as the independent variables, and the threshing efficiency, the percentage of damaged berries, and the capacity as the dependent variables. From the analyses of data, it was seen that all the independent variables exerted significant influence on the threshing efficiency, the percentage of damaged berries, and the capacity. In general, threshing efficiency showed an increasing trend atincreased feed rates for all the different contact lengths. It was most influenced by the peripheral velocity. Threshing efficiency was found to peak around 300 m1min. beyond which it showed a decrease. The percentage of damage was observed to be higher at higher feed rates and lower peripheral velocities. The values of percentage of damage was only between 0.05-0.55 %, which indicated that the therrnofoam assisted in reducing damage to the berries. The capacity showed an increase with the feed rate. However, it did not vary much as the contact lengths were changed. The capacity generally increased with increase in peripheral velocity. A multiple regression equation was developed for the prediction of the power requirement. The maximum power requirement of 0.46 hp was at a feed rate of 50 kglh and a peripheral velocity of 296.9 m1min. The cost of threshing using this thresher was only Rs 1.42 per kilogram, showing that the thresher was very economical. It was highly cost effective compared to the cost of manual threshing which is Rs 6.01 per kilogram.