An expeller press is a screw-type machine that mainly presses oil seeds through a caged barrel-like cavity. Some other materials used with an expeller press include meat by-products, synthetic rubber and animal feeds. Raw materials enter one side of the press and waste products exit the other side.
How does an expeller work?
Most expeller machines are set up so that the target item is placed between two heavy metal plates. When turned on, the machine will typically rotate those plates, progressively pressing the target harder and harder. Any oil that is released during this process is caught in a runoff tray, where it is filtered and collected for later use.
When did expeller presses start?
The earliest expeller presses utilized a continuous screw design. The compression screws were much like the screws of a screw conveyor —that is, the helicoid flighting started at one end and ended at the other. Valerius Anderson invented the interrupted screw design and patented it in the year 1900.
Is it better to use an expeller or extract oil?
Using an expeller still tends to be less efficient than extracting oils through chemical means, but many people believe that it is healthier and more environmentally conscious to avoid harsh additives, particularly in oils designated for human consumption.