Airlift (dredging device)

An airlift is device based on a pipe, used in nautical archaeology to suck small objects, sand and mud from the sea bed and to transport the resulting debris upwards and away from its source.

[1] Typically, the airlift is constructed from a 3-metre to 10 metre long, 10 cm diameter pipe.

Compressed air is injected into the pipe in one to three second bursts with an interval long enough to let the resulting bubble to rise to the higher, output end of the pipe.

Ejected debris can be either cast off (as in simply removing overburden) or collected in a mesh cage for inspection (as more often is the case in nautical archaeology).

Airlift pumps are governed by the physics of two-phase flow.