Types of Centrifugal Pump
- According to number of impellers
- Single stage pump
- Multi stage pump
- According to type of the casing
- Volute casing pump
- Vortex casing pump
- Diffuser casing pump
- According to head of liquid
- Low lift pump
- Medium lift pump
- High lift pump
- According to the type of impeller
- Closed impeller pump
- Semi-open impeller pump
- Open impeller pump
- According to direction of flow of oil
- Radial flow type
- Axial flow type
- Mixed flow type
Main Components of a Centrifugal Pump
- Prime mover
- Suction pipe
- Delivery pipe
Prime mover – The prime mover of a pump shall be an electric motor or a oil engine. It provides the rotational power to the shaft of the device.
Impeller – It is the rotating part of the device. Vanes or blades are arranged in series on it. The vanes are fitted on the shaft and rotated by the prime mover.
Casing – Casing is a hollow chamber surrounding the impeller. It is made as an air-tight unit. The sectional area of the casing gradually increases in the direction of the flow of liquid. This construction ensures the decrease in the velocity of the liquid and increase of the pressure.
Suction pipe – The top of the suction pipe is connected to the impeller (inlet). The bottom end is attached with a foot valve and a strainer.
Delivery pipe – The lower end of the delivery pipe is connected to the outlet of the pump. The liquid is pumped out through the other end of the pipe.
Working of Centrifugal Pump
Before the pump is set on for pumping, priming is done. Priming is done by filling water in the suction pipe and the impeller. While doing so, the air valve is opened. As a result, no air pocket is left in the casing. The presence of any air will certainly decrease the sucking capacity of the impeller.
After the priming is over, the pump is started. The prime mover operates the impeller. The vanes on the impeller creates centrifugal force inside the casing. Vacuum is created at the centre of the impeller(eye). Water from the reservoir reaches the casing through the inlet. Due to the centrifugal force, water is thrown radially outwards. As the sectional area of the casing gradually increases, velocity energy of the liquid is transformed into pressure energy. The liquid with increased pressure is pumped to a required height through the outlet. As the impeller goes on rotating, more water is pumped out.
Applications of Centrifugal Pump
- Water pumphouses
- Sewage treatment
- Oil refineries
Advantages and Disadvantages of Centrifugal Pump
- Low cost
- Suitable for pumping coolant
- Low efficiency
- Limited to be used at low pressure