Mainly two types of pumps are used to lift the water from the bore well to the overhead tank, namely
- Reciprocating pump
- Centrifugal pump
Engineering design of both pumps makes them work on different physical principle. Based on the design their power consumption, troubleshooting varies for the same unit of work they do. The objective of a pump is to deliver or move a liquid from one location to another location. The liquid transportation will consume an energy based on the parameters like pressure at which is to be transferred, viscosity and density of the liquid and the level it is available as suction and discharge. The action of gravity and friction will act against pumping.
Borewell which has a depth about 150 to 200 feet will use a pipe with foot valve as suction to the pump. The suction pipe is connected to the pump suction casing.
Comparison between reciprocating and centrifugal pumps for bore well water pumping:
To deliver water at high pressure a reciprocating pump is used. It is a slow machine and produces low flow rate. It has a piston and cylinder system. The electric motor drives the belt to provide the crank of the pump to rotate and make the piston to move to and fro in a cylinder. The cylinder is fitted with two non-return valves. Primping to the pump is not required in most cases. When a bore well and pumping system is located at a far place from the usage than the reciprocating pump is preferred. However, it is costly than the centrifugal pump it requires periodic maintenance like greasing, changing the belt. When compared to centrifugal pump work, its efficiency is high.
For less cost and low pressure, discharge with a high flow rate centrifugal pump can be used. It is modified as submersible pumps so that the pump and motor are fitted in a compact system and can be submerged in the water present in the well. When coming normal centrifugal pump it has a disadvantage of priming that is after some working day we have to pour water into its case to fill it water and remove all the air. So that when the pump has started no present in it, if air is present in the pump casing the impeller do not produce the pressure and water will not be pumped. This is the main problem caused by a centrifugal pump. To avoid this problem a non-return valve should be used at the discharge line of the pump. The non-return valve will make the water to stay in the casing after the pump is switched off. When the pump is started again, the water present in the casing and will produce the pressure due to impeller rotation. Centrifugal pump works deliver water with steady flow rate and consume less power.