Development of an improved modified Fitch apparatus for application in technologically less developed countries

Abstract

This study was conducted to assist in reducing post harvest losses in Africa and contributing to increased technology availability for agro-material testing. Principles considered in design of thermal conductivity probe include the heat transfer methods like conduction and convection. Fitch apparatus was reviewed and found to be deficient on heat transfer through convection and radiation. A modified Fitch apparatus was constructed and tested. It was designed based on radiative-convective-conductive heat transfer using non steady state heat transfer through non-line heat sources. The major components include an electric bulb, the casing, a digital thermometer and a sample hanger. The standard temperature of the system was kept at 81.50C for testing of products. The results of experiments carried on three samples of cocoyam, sweet potato, and Irish potato, shows K-values of 1.032Wm-1 0k-1, 0.92Wm-1 0k-1, and 0.604Wm-1 0k-1 respectively at specimen thickness of 0.025m and at moisture content of 71.3%. The Cronbach reliability test shows that the equipment had a reliability of 98% which is desirable. The developed Fitch apparatus is a major contribution to knowledge in agricultural equipment development in Nigeria.