A gear pump uses the meshing of gears to pump fluid by displacement. They are one of the most common types of pumps for hydraulic fluid power applications. The gear pump was invented around 1600 by Johannes Kepler. Gear pumps are also widely used in chemical installations to pump high-viscosity fluids. An internal gear pump has two interlocking gears of different sizes with one rotating inside the other. Gear pumps are commonly used for pumping high viscosity fluids such as oil, paints, resins or foodstuffs. They are also preferred in applications where accurate dosing or high pressure output is required
