Hand pumps for water lifting
Arm is raised
position
Practical Action
A roller can
be used to
keep the
bucket in
place
Pivot
Counterweight
Counterweight
drops as the
bucket is raised
The weight of the counterbalance is usually sufficient to balance half
the weight of the full bucket and water but in some cases is set to
counter the whole weight of the bucket and water if the user has
enough weight to return the lever.
Figure 3: A counterpoise lifting device, also known as a shadouf, over an open well. A
counterbalance helps lift the bucket of water.
Illustration: Neil Noble / Practical Action
However, when the water table is very deep or where the ground is very hard rock and groundwater
needs to be accessed via a borehole, it is usually necessary to install a hand pump to raise the
water. Introducing hand pumps also allows the water source to be sealed and reduces the
potential for source contamination during water collection. Groundwater hand pumps can be split
into two categories, shallow-well and deep-well.
Shallow-well pumps
The following section presents the main
type of pump used for shallow-well
water lifting.
A reciprocating suction pump has a
plunger or piston which moves up and
down in a two-valve closed cylinder. As
the plunger moves upward it forces
water out through the outlet valve and
at the same time draws water into the
cylinder through the inlet valve. Moving
the plunger down brings it back to its
starting position.
Plunger
or
Outlet
Valve
Foot or
Inlet
Valve
Figure 4: How most types of pump cylinders work.
4