Oil skimmers are mainly used to remove suspended tramp oil from the coolant surface. This works on principle f surface tension. PU belt is used for this application, in some case SS belts are also used. Belt holds in two pulleys one is drive and another is driven. With geared motor drive pulley rotates the belt in upward direction, during this oil from the surface get stuck with belt surface. This oil thus removed by a scraper mounted on top.

The oil skimmers capacity is depend on the belt width and belt size is decided with following parameters.
1. Tank depth. 2. Tank volume. 3. Tramp oil % in the tank. 4. Any greasy material is available there. 5. Temperature of fluid.