A gear pump is a type of positive displacement pump that uses the meshing of gears to move fluids. It consists of two or more gears that rotate within a casing, creating a vacuum that draws fluid into the pump and then pushes it out through an outlet. Gear pumps are commonly used in various applications, including hydraulic systems and fuel transfer, due to their efficiency and ability to handle high-viscosity fluids. These pumps are known for their simple design and reliability. They can be categorized into two main types: external gear pumps and internal gear pumps. External gear pumps have two gears that rotate outside each other, while internal gear pumps have one gear inside another. Both types are widely used in industries such as automotive, manufacturing, and oil and gas.