The device uses a rotating, oleophilic circular disk to collect the sludge and oil that float to the surface. The rotating discs of the skimmer pick up the oil that comes in contact with them and the oil scraped off from the disc and is collected in a tank. Collected oil is transferred by gravity to the oil sump It became popular as the accessory of coolant tanks, due to highly efficient and easy to use character. Driven at fixed speed by an electric drive. It comes in single disc or double diisc variant. It can be fixed on the tank containing the liquid to be skimmer.