What Is The Screw Press Method Of Oil Extraction?

The screw press method of oil extraction, also known as mechanical pressing or expeller pressing, is a common and traditional technique used to obtain oil from various oilseeds. Here's an overview of the screw press method:

Feeding:

The oil-bearing seeds or nuts are fed into the inlet of the screw press.

Pressing:

The seeds/nuts pass through a chamber where a rotating screw or worm shaft is located.

As the seeds move along the screw, they are progressively compressed, subjected to pressure, and heated due to the friction generated by the rotating screw.

The pressure and heat cause the oil to be released from the cells of the seeds.

Oil Extraction:

The expelled oil flows out through small openings or gaps in the press cage.

The extracted oil is then collected, while the remaining solid material, known as the pressed cake, continues along the press and is discharged separately.

Separation:

The pressed cake, which still contains some residual oil, can undergo additional extraction methods like solvent extraction to retrieve more oil.

The screw press method is preferred for its simplicity, cost-effectiveness, and ability to handle a variety of oilseeds. It doesn't involve the use of chemical solvents, making the extracted oil more natural. However, the efficiency of oil extraction may vary depending on factors such as the type of seeds, moisture content, and the specific design of the screw press. Different types of screw presses with varying configurations are available to suit the characteristics of different oilseeds and meet specific production needs.