The process of oil extraction has been existent from very early times. In those days, the seeds were merely cleaned and grinded with the use of grinders or stone mills. With the advancement of science and technology, the use of machines like Oil Expellers(also called as Screw Presses) were started for expelling or extracting oil from oil seeds and nuts. Oil Expellers play a very vital role in the oil extraction process.
A Screw Press is a mechanical machine that is used to press or crush oil seeds in order to extract the oil content from it. As we all know, oil seeds contain some amount of oil in them, which can be extracted by crushing them. During earlier times, traditional methods of grinding were used for oil extraction. These methods did extract oil from the seeds, but it didn't produce as effective results as the modern oil expellers do. There are two types of Oil Screw Presses or Expellers, which are namely as follows:
- Full Press Expellers
- Pre Press Expellers.
Oil Expellers / Screw Presses are screw type machines that presses oil seeds in order to extract the oil that contains in the seeds. These seeds are fed from one side of the press, which then enters into the pressing chamber. The machines uses pressure and friction from the screw drives to move as well as to compress the oil seeds. The oil that is expelled then seeps through the small openings. These openings are very small which prevents any kind of solid material or residue from the seeds to mix with the extracted oil. The waste or solid residue from the seeds exits from the other end of the expeller. This leftover residue is also known as oil cakes.