Improving The Efficiency of a Hammer Mill Under Different Operating Conditions

The research was conducted at the College of Agricultural Engineering / University of Damascus during the years 2022 - 2023, as the experiment was carried out on a dual-purpose machine (grinder + mixer) manufactured locally to study the effect of the diameter of the sieve hole, the number of hammers, and the concave clearance distance on the efficiency of the hammer mill in the machine, with three levels of hole diameter. The sieve (3-4-5) mm and three levels of the number of hammers (24-26-28) hammer, and two levels of the concave clearance distance (5-10) mm and its effect on productivity, energy consumed, specific energy, average particle size diameter, compression ratio of the crushed corn, and coefficient The effectiveness of the grinding and the machine’s efficiency. The results were analyzed using the program (Exstate 2014), and the differences between the averages of the parameters were tested according to the (LSD) test at the probability level of 0.05 and with three replicates. The obtained results showed that by increasing the diameter of the sieve opening from 3 to 5 mm and reducing the concave clearance distance from 10 to 5 mm, the specific energy and grinding efficiency were significantly reduced on the other hand, the productivity, the average diameter of the crushed particles and the machine performance were significantly increased. According to the number of hammers, its mentioned that there is no significant differences relative to the mentioned indicators. The study showed with regard to the compression ratio indicator that the smaller the diameter of the screen opening and the concave clearance and the greater the number of hammers, the greater the value of this indicator, and the largest value was (38%). The results obtained showed that the best operational treatment of corn grains for the hammer mill that was investigated was using a sieve diameter of 5 mm, a concave clearance of 5 mm, and a number of blades of 26 blades, which gave a productivity of (938.5) kg/h, and performance of machine of (96%) of specific energy is (3.142) wh/kg, the average diameter of the particles is (2.88) mm, and the grinding efficiency of (1.214) wh/m2.