What is a Centrifugal Pump? Types and different Parts

A Centrifugal pump uses the centrifugal force acting on it to transport liquids by converting the mechanical power (rotational energy) of the liquids

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A Centrifugal pump uses the centrifugal force acting on it to transport liquids by converting the mechanical power (rotational energy) of the liquids into pressure energy. This mechanical power generally supplies by the electric motor or engine. It is the simplest type of hydraulic machine that uses in a wide variety of industries and in many everyday appliances to move fluids from low to high-pressure areas. In 1475, engineer Francesco di Giorgio Martini designed a centrifugal pump as a mud lifter device.

The actual centrifugal pump was only discovered in the 17th century. Next, Denis Papin designed a centrifugal pump with straight blades. In 1851, the British designer John Appold created a centrifugal pump with curved blades.

These types of dynamic pumps mostly use in the food and chemical industry to easily transport viscous liquids. These pumps are cheaper than other positive displacement pumps. In simple words, it’s a great pump that can work efficiently in a different application.

Read also: Types of Jet Pump

Working Principle:

The centrifugal pump working principle is according to the basic principle of the angular momentum principle. It states that the change in the angular momentum of a revolving particle is equivalent to the applied force. It represents, when a specific amount of the fluid rotates with the help of an external force (force provide by an electrical motor or a turbine), a centrifugal force appears on it which further converts it into pressure.

Some part of the energy converts into the fluids’ kinetic energy. The water or other liquids enters axially into the housing eye. After that the water strikes with the vanes of the runner, and runner blades rotates the water tangentially and centrifugally outwards until it passes through all the components of the runner and enters into the diffuser portion of the housing. As the water passes the runner, both pressure and velocity increase. The diffuser or the spiral-shaped part of the housing reduces the speed of the water and increases the pressure of the water.

centrifugal Pump

In simple words, in a centrifugal pump, diffuse converts the impeller kinetic energy into the pressure energy of the liquid, with which the liquid is transferred up to a specific height. Fluid or water rises to a certain height due to the centrifugal force acting on these fluids or water. Therefore, this dynamic pump knows as a centrifugal pump.

Major Parts of Centrifugal Pump:

The major components of the centrifugal pump are given below in details.

1)  Casing

The casing is a narrow air passage around the impeller. It designs in such shape that it converts the fluid kinetic discharges by the impeller outlet energy into pressure energy before the fluid exits the casing and inserts into the discharge pipe.

There are three main types of the centrifugal casing.

(a) Volute Casing

It has spiral type design. Volute casing has gradual increase in the flow area. As the flow area increases, the speed slows and pressure of the fluid increases. This type of casing is given in the above diagram.

(b) Vortex Casing:

The vortex housing introduces a circular cavity between the casing and impeller. It uses to avoid energy loss due to the creation of swirls. These types of casings have high efficiency than volute casings.

(c) Guide blades Casing:

In this type of casing, the runner surrounds with the help of different number of guide blades. These blades attach around a ring that is known as diffuser. The guide blades design in such a way so that it does not affect the water exiting the impeller as it enters the diffuser. As the area of these blades increase then the water velocity reduces and its pressure energy increase. Mostly, the casing remains concentric with the impeller.

2)            Suction pipe:

The lower end of the suction pipe immerses in the water to that we want to lift up while connect the other end with the centrifugal pump inlet.

This part of the centrifugal pump has a foot and strainer valve at its bottom end. The role of these valves is to remove debris like sands, leaves and allow the water to flow upwards.

3)    Rotating Parts:

These parts of the centrifugal pump consist on an impeller and a shaft:

i) Impeller:

Impeller includes in the most important components of the centrifugal pump.  It increases the pressure and speed of the fluid. The impeller gives centrifugal acceleration to fluid. It further divides into below-given parts.

a) Open impeller.

The impeller has no crown and bottom plate. Open impeller can be used to remove liquids that contain solid particles, like water having paper pulp or sand e.tc.

b) Close impeller:

These impellers have cover plates on both sides of the blades. The close impeller uses to obtain pure water.

c) Semi-open impeller:

This type of impeller has only base plate but it doesn’t have crown plate. These impellers are for the fluids having loaded debris.

ii) Shaft:

Shaft uses to turn the impeller. It designs to transmit the torque generated when starting and operating the impeller and other revolving parts.

iii) Shaft sleeve:

The sleeve prevents the shaft of the pump by leakage and corrosion. One end of the sleeve must be sealed.

4)  Delivery Pipe:

This part of the centrifugal pump uses to lift fluid till required area. One end of the delivery connects with the outlet of the pump and other end connects with the height where we want to transfer fluid.

See also:

Transfer Pump