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

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(after Fraeikel (1997))

Ken Chatterton / Glenda McMahon © WEDC Loughborough University

a) Direct lift b) Suction c) Displacement

Atmosphericpressure

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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