Gear pumps are widely used in many fields due to their compact structure, smooth operation, wide application range and simple maintenance. In terms of performance evaluation, it is necessary to pay attention to key indicators such as its high efficiency and stability, flow and pressure performance, and noise and vibration levels.

Two main architectures are used: external gear pumps (two identical gears on parallel shafts) and internal gear pumps (a smaller rotor inside a larger ring gear with a crescent partition). External gear designs are compact and widely used in hydraulic systems, while internal gear units offer superior suction capability and better tolerance for high viscosity fluids; they are often selected for filling and emptying duties and can provide bi‑directional flow. For very high viscosities, internal gear pumps are typically the first choice.