Effect of Hammer Shape and Impact Area on Hammer Mill Performance under Different Feed Rates

The research aims to compare the performance (PC) and specific energy consumption (Spc.) of the hammer mill when using the T-hammer against the (traditional) rectangular hammer. A homemade mill with four hammers was used in experiment. 36 treatments: 2 hammer shape x 3 impact area (840, 720 and 960 mm2) x 2 feeding rates (1500 and 3000 g min-1) x 3 replicates, with completely random design. The results showed that there was no significant effect of hammer shape on PC at the feed rate of 3000 g min-1, while there was an effect at the rate of 1500 g min-1. An effect was also found for the impact area on the PC at both feeding rates and on Spc., as an inverse relationship appeared between the impact area and mill productivity at the feed rate 1500 g min-1. The area of 720 mm2 surpassed the area 480 and 960 mm2 at the rate of feeding 3000 g min-1, as it recorded 1215.65 g min-1 compared to 950.65 and 882.65 g min-1, respectively. There is effect of feeding rate on PC and Spc. The traditional hammer is recommended for simplicity of design, manufacture and performance at high feed rates compared to the T-shaped hammer.