Air lift pump energy conversion apparatus

Abstract

This apparatus has a plurality of vertical lift tubes immersed in water and arranged to discharge water into a hood at their upper ends for driving a turbine-like fluid motor. Each lift tube receives a much shorter, smaller diameter inner tube at its lower end. A horizontal partition extends between the inside of each lift tube and the corresponding inner tube. Compressed air is introduced periodically into the annular space between the lift tube and its inner tube below this partition. The lift tube has a water inlet opening located above the partition and below the top of its inner tube. SUMMARY OF THE INVENTION The present invention is directed to a novel apparatus for pumping water up through a tube by a succession of coherent air bubbles, each of which extends completely across the interior of the tube as it rises up the tube. The upwardly flowing water operates a fluid motor device, preferably a turbine or the like, whose water-driven rotation may be used for generating electricity or for other purposes. In accordance with the presently preferred embodiment of the invention, the present apparatus comprises a vertically elongated, open ended lift tube which extends down into a body of water from an upper end which is below the water level. Near its lower end the lift tube holds concentrically a smaller diameter, much shorter inner tube and a transverse partition extending between the two tubes above the lower end of the inner tube. Compressed air is introduced into the space between the two tubes below this transverse partition to form a coherent air bubble which forces water down from this space into the inner tube at its lower end. This air bubble then enters the inner tube at its lower end, rising up the inner tube and passing from the upper end of the inner tube into the lift tube as a coherent air bubble which extends completely across the interior of the lift tube. The lift tube has a water inlet opening located above the transverse partition and below the upper end of the inner tube, so that additional water may be drawn into the lift tube through this opening by the rising air bubble. Preferably, several such lift tubes are supported side by side in the water below a chamber into which all of the lift tubes discharge upwardly flowing water. The air bubbles break up at the lower end of this chamber. A rotary turbine-like device in this chamber is driven by the upwardly flowing water discharged from the upper ends of the several lift tubes. This turbine may drive an electrical generator or alternator or any other mechanically driven device for doing work. A principal object of this invention is to provide a novel and improved apparatus for driving a fluid motor, preferably a turbine-like device, by an upward flow of water which is pumped up by bubbles of a suitable gaseous medium, preferably compressed air. Another object of this invention is to provide a novel air lift pump for pumping water up through a tube from a lower level to a higher level. Another object of this invention is to provide such an air lift pump which has a novel arrangement for forming an air bubble at the lower end of a lift tube which remains coherent and extends completely across the inside of the lift tube as it rises up the latter to pump water upwardly through the lift tube. Another object of this arrangement is to provide an air lift pump as just stated having a novel water inlet arrangement near its lower end for adding to the supply of water which enters the lift tube in response to the pumping action of the rising air bubbles.

Dependencies are inferred from the claim text.