Centrifugal pump 

Construction:

Centrifugal pump works on a principle which states that if a fluid of a certain mass is given a force, it gets thrown outward radially. The main parts of the centrifugal pump include

• Suction eye 

• Vanes

• Impeller

• Casing

• Suction pipe

• Discharge pipe

The suction pipe is connected to the sump or a ground level tank from where the fluid has to be pumped. This pipe at the sump is connected with strainer thus restricting any foreign particles entering into the pump. Generally, the length of the suction pipe is less and thus the friction loss will also be less.

The other end of the suction pipe is connected to the suction eye of the pump. The suction eye is the first point of entry of water into pump. The discharge pipe is connected to the highest level where the fluid has to be delivered.

Since the length of the discharge pipe is high the friction loss will also be higher at the discharge end. The casing of the pump is of gradually increasing cross sectional area. It means that velocity of the fluid is decreased in order to attain pressure energy. Hence, the casing does the work of reducing the velocity of the fluid.

Working

The process liquid enters the suction nozzle and then into eye (center) of a revolving device known as an impeller. When the impeller rotates, it spins the liquid sitting in the cavities between the vanes in an outward direction and provides centrifugal acceleration.

As the liquid leaves the eye of the impeller a low-pressure area is created causing more liquid to flow toward the inlet. Because the impeller blades are curved, the fluid is pushed in a tangential and radial direction by the centrifugal force. This force acting inside the pump is same as the one that keeps water inside a bucket that is rotating at the end of a string.