By drawing a neat diagram explain the construction and working of a common water pump.
By drawing a neat diagram explain the construction and working of a common water pump.
Common Water Pump or Lift Pump
1. It is based on the principle that air exerts pressure can support vertical length of water in a closed tube.
Construction
1. It consists of two cylindrical iron tubes A and B, such that tube A has a larger diameter than tube B.
2. Tube B is sunk in the ground, such that its lower end is well within the underground water table.
3. At the junction of tubes A and B a foot valve junction is fixed, which opens in the upward direction.
4. Tube A is fitted with a watertight piston having a valve (piston valve), which opens in the upward direction.
5. To the piston is fitted a straight rod, which is connected to the handle of the pump.
6. Tube A is provided with an opening on its side near the top, from which water flows out.
Working
1. In figure (a), imagine the piston of the water pump in tube A at its lowest position, such that water is at the junction of tubes A and B, and the valves and are closed.
2. In figure (b), when the piston is raised upward, it sweeps the air above it outward. This results in the drop in pressure inside tube A.
3. To make up for the drop in pressure, the atmosphere exerts pressure on the ground, which in turn forces the underground water upward by opening the valve.
4. The water continues flowing into tube A till it is filled up to the base of the piston. At this moment, the valve closes due to the weight of water above it.
5. The valve remains closed on account of atmospheric pressure from above.
6. In figure (c), When the piston is lowered by working the handle, the water within tube A gets trapped as it cannot flow downward.
7. This trapped water exerts upward pressure on the piston valve and forces it open. On account of the opening of the piston valve the water trapped in tube A, flows up the piston.
8. This water will not flow downward as the piston valve closes.
9. In fig, (d), when the piston is raised upward by working the handle, the water above the piston flows out through the spout.
10. However, due to this movement the pressure within the foot valve and piston again falls.
11. Thus, again the atmospheric pressure pushes up the groundwater, by lifting up the foot valve.
12. The piston remains closed.
As the piston is moved up and down, more and more underground water is lifted up.
Common Water Pump or Lift Pump
1. It is based on the principle that air exerts pressure can support vertical length of water in a closed tube.
Construction
1. It consists of two cylindrical iron tubes A and B, such that tube A has a larger diameter than tube B.
2. Tube B is sunk in the ground, such that its lower end is well within the underground water table.
3. At the junction of tubes A and B a foot valve junction is fixed, which opens in the upward direction.
4. Tube A is fitted with a watertight piston having a valve (piston valve), which opens in the upward direction.
5. To the piston is fitted a straight rod, which is connected to the handle of the pump.
6. Tube A is provided with an opening on its side near the top, from which water flows out.
Working
1. In figure (a), imagine the piston of the water pump in tube A at its lowest position, such that water is at the junction of tubes A and B, and the valves and are closed.
2. In figure (b), when the piston is raised upward, it sweeps the air above it outward. This results in the drop in pressure inside tube A.
3. To make up for the drop in pressure, the atmosphere exerts pressure on the ground, which in turn forces the underground water upward by opening the valve.
4. The water continues flowing into tube A till it is filled up to the base of the piston. At this moment, the valve closes due to the weight of water above it.
5. The valve remains closed on account of atmospheric pressure from above.
6. In figure (c), When the piston is lowered by working the handle, the water within tube A gets trapped as it cannot flow downward.
7. This trapped water exerts upward pressure on the piston valve and forces it open. On account of the opening of the piston valve the water trapped in tube A, flows up the piston.
8. This water will not flow downward as the piston valve closes.
9. In fig, (d), when the piston is raised upward by working the handle, the water above the piston flows out through the spout.
10. However, due to this movement the pressure within the foot valve and piston again falls.
11. Thus, again the atmospheric pressure pushes up the groundwater, by lifting up the foot valve.
12. The piston remains closed.
As the piston is moved up and down, more and more underground water is lifted up.
