There was an air lift pump, back in the mid 90's, that used pillow sized bubbles instead of normally small bubbles. It required a high volume air pump. I believe that it was patented but never went into full production, probably they couldn't raise enough money for tooling. It supposedly had a fairly high output. Instead of using the bubbles that water can simply slip around as it rises, these pillows fill a 1 inch tube so that nothing can get around it. It is hard to communicate the idea but I will try. I'm not going to error check this so please excuse.
There are two containers that are used. Both could be made of PVC. The both containers are roughly cup shaped with on that in smaller and placed inside the other. The bigger one(brown) about 4 or 5 inches dia., has holes cut in it for water to enter through and it rests on the bottom of a water column. The second one(black)about 3 inches dia., does not rest on the bottom and fits into a 1 inch plastic tube. This tube goes through the wall of the bigger container at the top and is otherwise sealed.
Air is pumped into the outer cup(white arrow) and it starts to fill downward, pushing the water line with it(highest dotted line). As more air is pumped in, the water line drops below the lip of the small cup, I guess that surface tension resists letting the bubble(s) from bleeding over the edge at first and the water line continues to drop(wavy blue line).
At some point, the surface tension is overcome and the water floods over the edge upward, air the way around the lip of the cup, all at the same time. As the water escapes from the outer chamber, then the water, on the outside line goes back up to the first dotted line while the air inside the smaller cup begins to rise up the walls of the smaller cup (lower blue dotted line). Once again, surface tension doesn't allow the water to break up into little bubbles. Instead, this volume of air forms a pillow of air as it is compressed and driven into the upflow tube.
Then a bubble that 1 inch diameter by some length (1", 2", 5" according to how it was tuned, begins to be lifted up the tube, perhaps one per second or so.
Water flows into the bigger chamber as the pillow goes on its way up the tube and the cycle repeats its self.
I understand that it was hard to tune and the lip ring of the smaller container needed to be closely controlled during fabrication and has to be very level as you would expect. These guy put this in a pool or something so that there was a tall water column and they said that the water shot out like a garden hose as it starts, when there are air bubbles in it. Or like a water machine gun. I believe that their expectation was that you would put this think inside an even larger PVC tube that is capped at the bottom. You would place this behind the tank. It was suppose to work well with good volume but only have above one or two feet of head pressure one is got above the tank's water line.
