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'''Suction pumps'''<br>

In a suction pump, the cylinder is above the water table, usually near the top of the pump head. The rising main extends below the water table. When the pump is operated, during the upwards stroke it appears that water gets “sucked up” through the rising main into the cylinder. In fact, the atmospheric pressure forces the water into the area of low pressure underneath the piston. The theoretical limit to which the atmospheric pressure can push up water is 10 metres (m). In practice, suction pumps can be used to lift water up to about 7 or 8 m.