The belt oil skimmer utilizes a motor-operated belt and a pulley system that runs through the contaminated liquid to pick up tramp oil from the surface. The belt scrapes through a tray near the top pulley where the oils get collected.

The disk oil skimmer uses a disk in place of a belt. Disk skimmers offer a slightly higher oil pick-up rate compared to belt skimmers and can be very useful for small tanks. 

Drum skimmers are designed to float on the surface of the tanks. The motor-driven drums turn slowly adhering tramp oils to its surface and rotating around to the wiper blade which scrapes the oil off.

Hydrocyclone skimmers apply high centrifugal force to separate tramp oil from liquids. It comprises of a conical-shaped cyclone chamber that has two exit outlets located at each end with one inflow inlet on the side. The liquid enters the chamber and is spun at an extremely high centrifugal force. The heavier liquid is pushed to the walls of the chamber and discharged through the narrow outlet at the bottom, while the lighter oil moves to the center of the chamber and is discharged through the top outlet.

Coalescer oil skimmers have a tubular bed through which the fluid is made to pass through. This bed contains oleophilic (oil attracting) material that collects all sizes of oil globules. The oil sticks to the bed and the oil-free fluid passes back into your solution tank.