Pumping water up with minimal power...

[Externet]

Hello all.

A tiny air pump as in a fish tank  'undergravel tank filter'  feeds air into the smaller diameter hose on top (images) and the bubbles created at bottom lift the water in the larger pipe, working as a circulation pump with bottom suction, top discharge.

  Is there a limit of water lift height with this bubbling method ?  What determines the limit ?  The gap between bubbles, flow of bubbles, size of bubbles, diameter of tube ?   All interacting ?   It is a cousin of the Venturi principle ?  The depth at which the bubbles start is irrelevant if deep or shallow, right ?

 I can guess/visualize a looong tube carrying water very high just by the up-flow of bubbles.

 

[Images borrowed from the web]

 

 

[sethoflagos]

The air bubbles reduce the overall density of the fluid mixture in the tube. Ignoring complications like friction etc., hydrostatic equilibrium demands that fluid surface height (measured from the base of the tube) multiplied by density is the same both inside and outside the tube.

In principle, half the density, double the height. Though there are always losses in practice.