There are several methods of expressing liquid from solid-liquid matrix. The available designs may be placed in two groups:
*Batch process
*Continuous process
The continuous types of presses are screw presses or expellers. Now-a-days mostly continuous screw presses or expellers are being used. These presses were first invented in 1903 by Anderson in USA. This is the first continuously operating mechanical expeller.
The expeller was used to express oil from flaxseeds and whole cottonseed. In 1910 Krupp licensed these machines in Germany where they were used primarily as a forepress unit ahead of hydraulic presses.
The expeller has undergone various types of changes in quantity, quality and efficiency and has become the modern day expeller over the years.
In 1933, a new United States competitor, the French Oil Mill Machinery Company, introduced the ‘screw press’.
Expeller pressure
