A centrifuge is a device which allows to remove contaminants from oil products relatively rapidly. Centrifuge can separate small size contaminants from diesel fuel, which might not be possible to remove but other methods.
Centrifuges are now widely used for purification of oils used in aircraft, vessels and ground vehicles. Centrifuge operation requires a lot of electric power, and are mostly efficient when used on viscous fuels and pre-heating.
Contaminants and water are removed from the fuel by the centrifugal force. A centrifuge usually consists of a drum with solid or perforated walls. This drum rotates in a stationary housing. The internal surface of the rotor is often covered with filtration fabric or a thin metal mesh.
The centrifugal force causes separation of the oil into sediment and liquid. Depending on the process, centrifuges can be continuous or batch operated.
Batch centrifuges operate as follows. The device is engaged, then the drum is filled. The drum rotates at a constant speed, and the substance inside is separated. When the process of purification is complete, the drum is stopped and unloaded. The sediment is removed after the centrifuge stops, or even when the drum rotates at a slower speed.
Batch centrifuges are usually built with a vertical shaft. Material can be unloaded either from the top or from the bottom. The latter is considered more convenient, requiring less physical effort.