Due to the action of a centrifugal oil pump, the velocity and pressure of the liquid flow from the impeller inlet to the outlet can be increased. The liquid discharged by the impeller passes through the pressure chamber, and most of the velocity energy is converted into pressure energy, which is then transported out along the discharge pipeline. Due to the discharge of liquid, low pressure or vacuum is formed at the inlet of the impeller. The liquid in the suction pool is forced into the inlet of the impeller under the action of liquid level pressure, and the rotating impeller will continuously suck in and discharge the liquid.

In the volute, the liquid slows down due to the gradual enlargement of the flow channel, converting some of the kinetic energy into static pressure energy, and then flows into the discharge pipeline at a high pressure and delivers to the required location. When liquid flows from the center of the impeller to the outside, a certain vacuum is formed in the center of the impeller, because the pressure above the liquid level in the storage tank is greater than the pressure at the inlet of the oil pump, and the liquid will continuously press into the impeller. The impeller will run continuously, and the liquid will be continuously sucked in and out.