The airlift pump – also called mammoth pump – exploits the increase of the oxygen intake in water under pressure. At the same time, rising air is used to lift – and therefore circulate – water. This makes the mammoth pump suitable for aerating and circulating large volumes of water. An airlift pump is often used in situations where maintenance needs to be kept to an absolute minimum.
There are no rotating parts in the pump itself, only a riser pipe in which fluid and air are combined. The pump system as a whole is not 100% maintenance free as equipment is needed to feed air into the pump.
Air is fed into the bottom of the riser pipe where it is combined with the fluid. This changes the density of the fluid, causing the combined medium to rise up through the pipe.
The efficiency of an airlift pump depends on two things:
- The submerged length (Hs) in relation to geodetic head (Hgeo)
- Air speed through the fluid and the velocity of the medium through the pump. The greater the difference between the respective velocities of the fluid and air, the lower the overall efficiency of the pump.
Under optimal conditions the airlift pump can reach efficiency levels of approx. 35-40% at an Hs/Hgeo of 2/2.5 and an air speed of 10 m/s.