One of the options to produce the vegetable oil from the seeds of oil-yielding plants is extraction or pressing of the raw input material — oil seed meal — with the use of M8-MShP screw-type extruders (oil expellers).
Principle of operation of the oil expeller is as follows:
The raw material (sunflower seeds) is charged into the oil mill receiving hopper by a screw conveyor from the grain elevator. Then the seeds are fed into the separator where they are cleaned from contaminants and metallic impurities. After that the seeds are hulled, ground and, when hot pressing, dried and heated in the oil seed cockers of special design, and then conveyed to the oil expeller.
Pre-ground, having passed the thermal treatment and pre-heated up to the required temperature, the oil seed meal of oil-bearing crops (60-90 °C) is pressed in oil expeller. The oil is pressed in the extracting box consisting of several cages (stages).
The extracting box has four stages (I-II-III-IV). While the material is passing through the stages I to IV the pressure rises, i.e. each cage (chamber) is less in volume then the previous one. Therefore, when the oil seed meal passes through the stages the screw shaft (worm) compresses and squeezes it out through the gaps of laths in the extracting box. The oil pressing itself occurs at the stage III and IV.
With a view to increase the material upthrust in the extracting box a cone is mounted in the end of the chamber. By setting up the gaps between the cone and the cone ring the thickness of the oilcake is adjusted.
The pressed out oil flows down through the gaps in the extracting box plates into the oil collector, and the oilcake shells get to the screw conveyor inlet and are discharged beyond the unit location. The collected oil is pumped over to the place of destination.
The oil mill equipment can be mounted on a common base plate thus facilitating transportation, installation and commissioning of the equipment (the shipment by trucks is possible).