| Abstract: |
This study was conducted at El-Mona wheat mill in Abo-Hammad, Sharkia Governorate during the summer season of 2003.Wheat milling process aims to mill the available wheat into flour that meet the varied need of the flour consumer. Then, the milling process must be conducted more efficient.According to that, this study was carried out to choose the proper conditions to operate both of cleaning and milling processes with higher performance.The performance of cleaning process was tested under different operational factors included:1. Feeding rates of 12, 14 and 16 Mg/h.2. Inclination angles named 10, 12 and 14 degree.3. Air suction which was adjusted under values of 1, 1.26 and 1.52 kPa. And milling machine was operated under:1. Feeding rates of 8, 9 and 10 Mg/h.2. Roll clearances had various values according to the nature of mill stage as follows:B1 (1.65, 1.95 and 2.25mm),B2 (1.20, 1.50 and 1.80mm),B3 (0.50, 0.80 and 1.10mm),B4 (0.45, 0.75 and 1.05mm) andB5 (0.70, 1.00 and 1.30mm).Cleaning efficiencies were calculated and milling process was evaluated according to the percentages of pass and break release and comparing them with the optimum values for each stage.The obtained results of this work can be summarized under the following items:5.1. Cleaning process5.1.1. Inclination angle:Using inclination angle of 12 degree was accompanied with higher efficiencies compared to the others (10 and 14º). These efficiencies were 99.46, 99.38 and 99.35% under feeding rates of 12, 14 and 16 Mg/h and air suctions of 1, 1.26 and 1.52 kPa.5.1.2. Feeding rate:In relation to feeding rate, the results showed that cleaning efficiency can be improved in the case of using feeding rate of 12 Mg/h in comparison of (14 and 16 Mg/h), these efficiencies were 99.46, 99.35 and 98.80% under different inclination angles and air suctions.5.1.3. Air suction:On the other hand, it was cleared that cleaning process was operated more efficient under air suction of 1kPa compared to the others (1.26 and 1.52 kPa), these efficiencies were 99.46, 99.35 and 99.20%.5.2. Milling process5.2.1. Feeding rate:The use of feeding rate of 9 Mg/h insure a good performance of milling device which gave the nearest values of pass and break release percentages compared to the standard values for all stages of milling in comparison to the other feeding rates of (8 and 10 Mg/h).5.2.2. Roll clearance:The proper roll clearances for five stages of milling were 1.95, 1.50, 0.80, 0.75 and 1mm for 1st, 2nd, 3rd, 4th and 5th stage, respectively, under different feeding rates.RECOMMENDATIONSThe major conclusion and recommendations of the present study based on the obtained results were as follows:1. The cleaning system can be operated more efficient in the case of adjusting the sieves under inclination angle of 12◦, use of air suction of 1 kPa, and feeding the wheat grains with rate of 12 Mg/h.2. Wheat milling efficiency can be improved by using feeding rate of 9 Mg/h for all stages and adjusting the clearances between the rolls at 1.95, 1.50, 0.80, 0.75 and 1mm for 1st, 2nd, 3rd, 4th and 5th stage, respectively.
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