Wear of disc mill hammer in wet grinding processes on groundnut cake for fish feed production

Abstract

There is need to determine the wear rates of disc mill hammer used for grinding groundnut cake, a major plant protein in fish feed. This surface wear damage characterised by scoring, cutting, deep grooving and gouging on a metal surface leads to high costs of production. The hammer wear rate was carried out using disc mill for different combinations of processing conditions: disc speed of 2,175, 3,900 and 4,350 rpm; screen size of 1.0, 2.0 and 3.0 mm; moisture contents of 12, 14 and 16% w.b. at 300 operating hours. Response Surface Method was used to optimize the operating variables. The wear rate was found to increase as the moisture content of the groundnut cake decreased. Quadratic models developed for the four responses (tip length loss, width loss, thickness loss and absolute mass) studied indicated the optimum conditions at disc speed 3,262.50 rpm, screen size 2.0 mm and moisture content 14% w.b. The study established that experimental data and model predictions agreed well.