A well is 14m deep with 1m depth of water at the bottom ie 1

A well is 14m deep with 1m depth of water at the bottom, i.e. 13m from ground to water surface. You have a pump which must be placed either in a well house at ground level or within a parallel well shaft which is dry, by the side of the well. Explain why is will not be possible to mount the pump at ground level in order to raise the water from the well? What is the minimum depth to which the well shaft must be drilled in order to allow the pump raise water to the surface. Assume that the intake pipe accesses the well through the wall of the port-hole and that its inlet is 0.5m below the surface of the water. Assume atmospheric pressure is 1010 hectopascals.

Solution

If the pump is placed at ground level, the suction pipe will have lift water from a depth of 13 meters. Atmospheric pressure can support only 10.3 meters of water, hence theoretical lift at suction cannot be more than 10.3 meters for centrifugal pumps.

Practically, the suction head of a centrifugal pump is limited to 26 feet or nearly 8 meters.If 0.5 meter length of pipe is immersed, 7.5 meters is above water. The well shaft should have a depth of 13 - 7. = 5.5 meters.