A gear pump is a type of positive displacement pump that uses a pair of meshing gears to transport fluids. It is commonly used to transfer liquids of various viscosities, including oils, chemical fluids, and other industrial applications. Gear pumps are divided into external gear pumps and internal gear pumps. In the former, the two gears are mounted on separate shafts, while in the latter, the gears consist of one internal and one external gear, with the internal gear nested inside the external gear.