Centrifugal Pump | Different Types And Application Of Centrifugal Pump
WHAT IS CENTRIFUGAL PUMP ?
Centrifugal pump is a hydraulic machine which converts the mechanical energy into pressure energy and a centrifugal force acting on the fluid in the pump. In general, the hydraulic machines which convert mechanical energy into hydraulic energy are called pumps.
Generally, a centrifugal pump works when a certain mass of liquid is rotated by an external torque, the rise in pressure head of the rotating liquid takes place. The rise in pressure head at any point of the rotating liquid is proportional to the square of the tangential velocity of the liquid at that point. The liquid will be discharged at the outlet of the impeller with a high-pressure head because the radius of the outlet impeller is more. For a higher radius, the flow of liquid of the pump is in the radial outward directions. The centrifugal pump acts as a reverse of an inward radial flow reaction turbine. It is a basic working principle of the centrifugal pump. Next page, we will discuss the work done by the centrifugal pump.
DIFFERENT TYPES OF CENTRIFUGAL PUMP
According to the construction, application, design, and service, there are three types of centrifugal pump are available. 1. According to the shape of impeller and casing. 2. According to the type of impeller. 3. According to the working head. These three types of centrifugal pumps are also divided into sub-three categories.
1. According to the shape of impeller and casing
a)Volute or spiral casing type pump
b)Vortex ( whirpool ) casing type pump
c)Diffuser type pump
2. According to the type of impeller
a)Closed or shrouded impeller
b)Semi-open impeller
c)Open impeller
3. According to working head
a)Low head centrifugal pump
b)Medium head centrifugal pump
c)High head centrifugal pump
APPLICATION OF CENTRIFUGAL PUMP
The application of a centrifugal pump is the most popular choice for different fluid movements. So there is a wide range of applications of centrifugal pump in different industries like waste management, oil and energy, agriculture and manufacturing industries, pharmaceutical industries, chemical and food industries etc. It is also used fire protection sprinkler systems, boiler feed applications, gas processing, waste water processing plants, municipal industry, irrigation, and flood protection.
MAIN PARTS OF CENTRIFUGAL PUMP
Parts of centrifugal pump are different types. But following are the main parts of the pump as discussed below:
1) Impeller
2)Casing
3)Suction pipe with a foot valve and a strainer
4)Delivery pipe
1. Impeller:-
Centrifugal pump impeller is the main rotating part of the machine. It consists of a series of backward curved vanes. It is placed on a shaft which is straightly connected to the shape of an electric motor.
2. Casing:-
The casing is an air-tight passage placed surrounding the impeller of centrifugal pump. It is designed in such a way that the kinetic energy of any fluid discharge at the outlet of the impeller is converted into pressure energy before the fluid leaves the casing and enters the delivery pipe. The design of the casing of centrifugal pump is almost similar to the casing of a reaction turbine. Following three types of casing are commonly used of a centrifugal pump:
A.Volute casing
B. Vortex casing
C.Casing with guide blades
A. Volute casing:-
Volute casing is a spiral type casing which surrounds the impeller. It increases the area of flow gradually. Increase the area of the flow decreases the velocity of flow as well as increases the pressure of the water flowing through the casing. Volute casing increases the efficiency of the pump but a large amount of energy is lost due to formation of eddies.
B. Vortex casing:-
Vortex casing is a circular chamber placed in between the casing of the pump and the Impeller as shown in the above figure. Formation of eddies is reduced for the circular chamber and the loss of energy is reduced to a considerable amount. Efficiency of a pump in vortex casing is much higher than the efficiency of a volute casing.
C. Casing with guide blades:-
This type of casing, the impeller is surrounded by a series of guide blades mounted on a ring which is known as diffuser. The guide vanes are designed in such a way that the water from the Impeller enters the guide vanes without stock. Increase the area of guide vanes reducing the velocity of flow through guide vanes and also increasing the pressure of water. Now the water from the guide vanes passes through the surrounding casing which is connected with the Impeller.
3. Suction pipe with a foot valve and a strainer:-
Suction pipe of centrifugal pump's one end is connected to the inlet of the pump and other end dips into water in a sump. Foot valve is a one-way type valve that is fitted at the lower end of the suction pipe. It is open only the upward direction. Strainer is also fitted at the lower end of the suction pipe.
4. Delivery pipe:-
It is a pipe whose one end is connected to the outlet of the pump and another end delivers the water at a required height is known as a delivery pipe.