The Working Principle of Centrifugal Pump

Date: 2022-10-21     From: Longding     Author: admin

The centrifugal pump is the use of impeller rotation and make water centrifugal movement to work. Using the motor, the pump shaft drives the impeller and the water to do high-speed rotating motion, the water occurs centrifugal motion, is thrown to the impeller outer edge, through the flow channel of the cochlear pump shell into the pump pressure water pipe.

The impeller is installed in the pump housing and fastened on the pump shaft. The pump shaft is directly driven by the motor. A liquid suction tube is connected with the suction tube in the center of the pump shell. The liquid enters the pump through the bottom valve and suction pipe. The liquid discharge outlet on the pump housing is connected with the discharge pipe.

Before the pump starts, the pump shell is filled with the liquid to be delivered.  After starting, the impeller is driven by the shaft to rotate at a high speed, and the liquid between the blades must also rotate with it. Under the action of centrifugal force, the liquid is thrown from the impeller center to the outer edge and obtains energy, leaving the outer edge of the impeller and entering the cochlear pump shell at high speed. In the shell, the liquid slows down due to the gradual expansion of the flow channel, and then changes part of the kinetic energy into static pressure energy. Finally, the liquid flows into the discharge pipe at a higher pressure and is sent to the place where it is needed. When the liquid flows from the center of the impeller to the outer edge, a certain vacuum is formed in the center of the impeller. Since the pressure above the tank level is greater than the pressure at the pump entrance, the liquid is continuously pressed into the impeller. As long as the impeller continues to rotate, the liquid will continue to be inhaled and discharged.

Air bound phenomenon

When there is air in the pump housing, because the density of air is much smaller than the density of liquid, the centrifugal force is small. The pressure difference between the top of the tank and the suction inlet is not enough to push the liquid in the tank into the pump, that is, the centrifugal pump has no self-priming ability, so that the centrifugal pump cannot transport liquid. This phenomenon is called “air trapping phenomenon”. In order to fill the pump with liquid, the suction pipe is usually installed at the bottom of the bottom valve with a screen. The bottom valve up to the reverse valve, the role of the filter is to prevent solid material into the pump damaged impeller or prevent the normal operation of the pump.