Patent ID: 7159854

Claim:
An apparatus for providing microbubbles of gas in a liquid, comprising: a vessel adapted to be positioned substantially vertically and adapted to contain a volume of gas under a second pressure exceeding ambient by at least 10 psi, in an upper portion thereof; means for introducing gas bubbles, the majority of which are of a size greater than 100 microns, into a liquid to form a liquid-gas mixture; elongate, hollow pipe means within said vessel, of interior cross-sectional area A i , for conveying said liquid-gas mixture under a first pressure greater than said second pressure to an interior of said vessel, substantially symmetrical in cross-section, situate in said vessel and proximate said upper portion of said vessel and extending substantially vertically downwardly within said vessel from said upper portion thereof, and having plug means situate at a lowermost distal end thereof for preventing egress of liquid vertically downward from said distal end; at least two apertures situate on said pipe means each disposed substantially perpendicular to a longitudinal axis of said pipe means and each extending from an interior of said pipe means to an exterior of said pipe means, each adapted to direct said liquid under pressure substantially horizontally outwardly from said pipe means; said vessel further comprising gas-liquid withdrawal means; said withdrawal means in communication with an interior of the vessel proximate a bottom portion thereof, adapted to withdraw a gas-liquid mixture having microbubbles of entrained gas therein from said Interior of said vessel, situate on said vessel at a position; said position being at a level on said vessel below a lowermost level within said vessel which bubbles of a size larger than 100 micron fall to before rising in liquid in said vessel, and at a level which bubbles of a size less than 100 microns fall to before rising in said vessel.