What is Centrifugal Pump?

A pump is a hydraulic machine which converts mechanical energy into hydraulic energy or pressure energy. A centrifugal pump is also known as Roto dynamic pump or dynamic pressure pump. It works on the principal of centrifugal force.

Centrifugal Pumps are the most commonly used pump type in the world. They are utilized to raise the pressure or include flow in a control volume. The centrifugal pump creates an increase in pressure by transferring mechanical energy from the motor to the liquid through the rotating impeller. The fluid flows from the inlet to the impeller centre and along its blades. The centrifugal force here by increase the liquid velocity and consequently also the kinetic energy is transformed to the pressure. There are various kinds of Centrifugal pump are available in the market with different construction details. But the working principle behind all of them remains same.

 

Classification of Centrifugal Pumps:

1. According to the Casting design
   a) Volume Pump
   b) Diffuser or turbine pump
2. According to the number of impellers
   a) Single stage pump
   b) Multistage or multi impeller pump
3. According to the number of entrances to the impeller
   a) Single suction pump
   b) Double suction pump
4. According to disposition of shaft
   a) Vertical shaft pump
   b) Horizontal shaft pump
5. According to liquid handled
   a) Semi open impeller
   b) Open impeller pump
6. According to specific speed
   a) Low specific speed or radial flow impeller pump
   b) Shrouded impeller
   c) Medium specific speed or mixed flow impeller pump
   d) High specific speed or axial flow type or propeller pump
7. According to Head(H)
   a) Low head if H<15m br="">b) Medium head if 15c) High head if H>40m

Component of a Centrifugal Pump:

• Impeller is the rotating component of the pump. It is made up of a series of curved vanes. The Impeller is mounted on the shaft connecting an electric motor.
• Casting is an air tight chamber surrounding the impeller. The shape of this casting is designed in such a way that the kinetic energy of the impeller is gradually changed to potential energy. This is achieved by gradually increasing the area of cross section in the direction flow.
• Suction Pipe is the pipe connecting the pump to the sump, from where the liquid has to lift up.
• Foot valve with strainer the foot valve is a non - return valve which permits the flow of the liquid from the sump towards the pump. In other words the foot valve opens only in the upward direction. The strainer is a mesh surrounding the valve; it prevents the entry of debris and silt into the pump.
• Delivery pipe is a pipe connected to the pump to the overhead tank.
• Delivery valve is a valve which can regulate the flow of liquid from the pump.

Advantages of Centrifugal Pumps:

• Its initial cost is low.
• Efficiency is high.
• Discharge is uniform and continuous.
• Installation and Maintenance is easy.
• It can run at high speeds, without the risk of separation of flow.