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There are three main physical principles used in handpumps to discharge water. They are:
• Direct lift – where a piston progresses up a cylinder raising the water above it.
• Suction – where atmospheric pressure acting on the surface of the source water pushes it into the expanding space below a piston moving upwards in a cylinder.
Pumping principles
For further information visit: http://wedc-knowledge.lboro.ac.uk/
(after Fraeikel (1997))
Ken Chatterton / Glenda McMahon © WEDC Loughborough University
a) Direct lift b) Suction c) Displacement
Atmosphericpressure
© W
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This is relevant when the cylinder is positioned above the level of the source water.
• Displacement – where a solid object is pushed into a confined body of water, causing some of the water to be displaced.
More than one of these principles can apply at the same time to the operating cycle of a handpump.
Developing knowledge and capacityin water and sanitation
Poster 36