Page:Popular Science Monthly Volume 89.djvu/113

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��and which are distributed tlirough the water in the pipe. The greater weight of water la the well overbalances the aerated water, and is forced upward and discharged

��One or more wells are sunk to a depth considcrahly below the level of the underground water. A pipe of large diameter open at the bottom is then sunk nearly to the bottom of each well. This is for the water discharge. When not pumping, the water in this pipe will be at the same level as that in the well. A second pipe of small diameter is also sunk to the bottom of each well, terminating in a chamber which sur- rounds the water-pipe. Air passes from this chamber through small perforations into the water-pipe, mixing small bubbles with the water, giving a "champagne effect." These bubbles rise very slowh', until they arc distributed throughout the entire column of water in the dis- charge pipe. Coincident with the ad- mission of air, the column of water elongates until it discharges.

The weight of water in the well over-

��balances the very much longer column of aerated water in the pipe. Thus the well-water flows into the discharge pipe, is aerated and in turn discharged.

The air pressure must be greater than the water pressure at the bottom of the well. Otherwise the water would force its way into the air-pipe and stop operations.

The water may be lifted vertically into a tank or reservoir or may be dis- charged into a "booster" and then carried horizontally. The booster is simply a vessel which permits the air and water to separate.

In the air-lift system there are abso- lutely no working parts, .such as pistons, \alves, etc., under ground, which are liable to wear, to rust, or to become de- fective with use. Air is supplied by an air-compressor, which ma>- be located far from the wells, if desired.

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