Today we are going to discuss the factors that govern the feeding rate of oil presses.
Material temperature mainly affects the degree of protein denaturation and moisture content. For conventional oil-pressing processes, the maximum protein denaturation of material flakes is required prior to pressing. Through the steaming-roasting process, protein denaturation takes place to destroy the cellular structure of materials, modify the elasticity and plasticity of proteins, and aggregate tiny oil droplets dispersed inside cells into larger droplets, so as to improve the oil yield.
Protein denaturation increases elasticity and reduces plasticity of materials, which requires greater external force for compression and shaping. Given the same feeding capacity, the motor load rises and the electric current increases. To keep the motor current within a reasonable range, the feeding rate has to be reduced as a temporary adjustment measure.
The moisture content of material flakes exerts a significant influence on protein denaturation. Materials subjected to steaming-roasting achieve maximum protein denaturation accompanied by certain changes in moisture content. Feeding moisture strongly affects protein elasticity and plasticity.
If the feeding moisture is excessively high, protein elasticity decreases while plasticity increases. Under identical feeding capacity, the motor current of the oil press drops, the oil-discharging position shifts backward, and the quantity of meal residue rises. Excessive meal residue recirculating back into the press interferes with normal feeding, and may cause feeding failure in severe cases.
If the feeding moisture is excessively low, protein elasticity increases while plasticity decreases. Under identical feeding capacity, the motor current of the oil press rises, the oil-discharging position shifts forward, and meal residue output increases. Excessive meal residue returning to the press hinders normal feeding, and may result in feeding failure under serious conditions.
The cake ring at the cake-discharging end of the oil press adjusts cake discharge thickness, which further changes the chamber pressure of the press.
A thicker discharged cake means lower cake-discharging resistance, lower motor current and faster feeding rate. Nevertheless, overly thick cake leads to higher residual oil content in cake and imposes extra burden on subsequent solvent extraction.
A thinner discharged cake brings higher cake-discharging resistance, higher motor current and slower feeding rate.
Arranging press bars is a skill-demanding operation that requires ample practical experience and technical know-how. Properly arranged press bars deliver high throughput, high oil yield, low residue output and well-formed press cake. Poor bar arrangement will lead to incorrect oil-discharging position, low oil output, excessive residue and loose or even shapeless cake. In severe circumstances, feeding failure may occur.
Above are the common factors influencing the feeding rate of oil presses. What other factors do you think will affect oil-press feeding rate? Feel free to leave comments for discussion and sharing.
