The impeller is installed inside the pump casing and secured to the pump shaft, which is directly driven by the motor. A liquid suction pipe connects to the middle of the pump casing. Liquid enters the pump through the foot valve 6 and the suction pipe. The liquid discharge port on the pump casing connects to the discharge pipe. Before starting the centrifugal oil pump, the pump casing is filled with the liquid to be pumped. After starting, the impeller rotates at high speed driven by the shaft, and the liquid between the blades also rotates. Under the action of centrifugal force, the liquid is thrown from the center of the impeller to the outer edge and gains energy, leaving the outer edge of the impeller at high speed and entering the volute pump casing.

The main flow components of a centrifugal oil pump are the suction chamber, impeller, and discharge chamber. The suction chamber is located in front of the impeller inlet and serves to guide the liquid towards the impeller. The discharge chamber mainly comes in three forms: spiral discharge chamber (volute type), guide vanes, and spatial guide vanes. The impeller is the important working element of the pump, the heart of the flow components, and consists of a cover plate and central blades.

Before the oil pump centrifugal pump starts working, the pump is first filled with liquid. Then the oil pump centrifugal pump is started, and the impeller rotates rapidly. The blades of the impeller drive the liquid to rotate. When the liquid rotates, it flows towards the outer edge of the impeller due to inertia. At the same time, the impeller draws liquid in from the suction chamber. During this process, the liquid in the impeller flows around the blades. In the flow around the blades, the liquid exerts a lift force on the blades. Conversely, the blades exert a force on the liquid with a force equal in magnitude and opposite in direction to this lift force. This force does work on the liquid, giving the liquid energy so that it flows out of the impeller. At this time, both the kinetic energy and pressure energy of the liquid increase.