THE SCREW WEAR INFLUENCE ON THE PERFORMANCE OF AN OILSEED EXPELLER

The main objective of the present study is investigating the influence of the tapered screw hardening treatment and screw operating hours on the abrasive wear at three different zones of feeding (A), crushing (B) and pressing(C) on the screw as well as the expeller performance during the oil expression process for determining the optimum time for the screw replacement. This study was carried out to compare the performance of two types of the tapered screws, the hardened (HS) and Non-hardened (NHS) to press flax seeds during 400 h of working at the recommended operating conditions of 9% for seed moisture content, 30 rpm for screw speed and 0.4 mm for outlet clearance. The obtained results revealed that, the HS would decrease the wear after 400 h of oil expression by about 30.54, 26.22 and 35% at A, B and C zones, respectively compared to NHS. The using of HS would increase the feeding capacity, expressed oil and expression efficiency by about 6.7, 7.44 and 5.56%, respectively more than the NHS. Also, the using of HS would decrease the oil in cake, and consumed energy by about 11.75 and 6.7%, respectively compared to the NHS. Ultimately, it is suggested to make replacement to the tapered screw with a new one after 300 and 400 operating hours for the NHS and HS, respectively, this mean that, the HS may give 100 h of oil expression more than the NHS.