Pumping height
explained
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Each pump we sell has a chart showing maximum
pumping height and litres per hour flow at different head or pumping
heights.
The information below is intended explain these calculations. |
"Head" Or maximum pumping height (Zero flow height)
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| Head is also known as the "No flow
or zero flow
height", "Lift" "shut off" etc, The point at which nothing comes out of a tube. It does not matter
what size tube* is used, this height is the same. *The flow is however
effected by the tube internal diameter. |
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Vertical lift
For a given pump, the higher water is pumped vertically - the lower the flow;
at a some
height the flow will be zero. The
terms "head height" or "lift" are used to indicate this
vertical height, measuring how high the
water can be pumped for a particular application.
Each pump has a published graph showing its flow rate at various heads. Waterfalls or streams
have the added factor of friction loss created by the
longer hose run required between the pump and the top of the waterfall or
stream. |
Static head
Why is the height from the pump to the top of the water not counted in the head
calculations?. It's called Static head. It does not count as pumping height
because the water is already at the surface and does not have to be pumped
there.
Maximum depth the pump can be located. depending on the pump there is a
maximum depth that a pump will operate. The larger the pump the deeper it's
suitable placement. Call us for help if you are planning a pump depth over 1.5m
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Pumping performance curve
Or litres per hour - vertical flow rates
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Pumping height
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Horizontal flow (tube friction)
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In calculating tube friction, the entire tube length must be
used. |
Friction loss - for waterfall or stream use. Pumping water through tubing adds resistance, so an allowance must be made for friction
loss inside the tube. As a rule of thumb add 10cm of head for every 1 meter
of horizontal tubing run. However as the size of the tubing has
a significant bearing on frictional resistance, the use of an undersize tube
will increase frictional losses. See chart below.
An
allowance for friction loss
must be added to the vertical distance (in meters)
measured from the surface of the pond, over which
you will be pumping the water. The resulting sum will be the 'Total Head' that the pump will be required
to lift the water. You should compare the flow rate that you require, to the flow rate
that the pump provides at this specific head. |
