Device for aerating liquids

Claim 1

A self-aspirating device for the aeration of liquids with air of atmospheric pressure in a vertically disposed cylindrical container having a predetermined internal diameter, comprising: a rotatable extended motor shaft extending upwardly into said container from below the latter; a motor located exteriorly of said container for driving said shaft in a predetermined direction of rotation; a hollow rotor arranged within said container near the bottom of the latter and carried by said shaft for rotation therewith, said rotor having vertically spaced horizontal top and bottom surfaces and four to eight peripherally spaced vertical impeller surfaces intermediate said top and bottom surfaces and extending from one to the other of the latter, each of said vertical impeller surfaces being oriented non-radially of said rotor away from the direction of rotation thereof and defining, in conjunction with corresponding sections of said top and bottom surfaces, a respective laterally projecting vane closed at its leading side and provided with a vertical air outlet opening at its trailing side, the maximum outer diameter of said rotor as measured at the locus of the apices of said vanes being between 1/8 and 1/15 of said internal diameter of said container; a stationary air intake pipe connected at one end to said rotor at said top surface thereof and extending therefrom out of said container, the connection between said rotor and said one end of said air intake pipe being sealed by a labyrinth packing, and the other end of said air intake pipe being in communication with the atmosphere; each of said vertical impeller surfaces defining in conjunction with the preceding one of said outlet openings as viewed in the direction of rotation of said rotor a respective impeller chamber which is open at the top and bottom thereof for admitting liquid thereinto from above and below, liquid so entering said impeller chambers being mixed therein with air aspirated into and exiting from the interior of said rotor via said outlet openings during rotation of said rotor, and the resultant miXture of air and liquid being propelled from said impeller chambers outwardly of said rotor toward the wall of said container; and a stator mounted in the bottom region of said container in surrounding relation to said rotor, said stator including upper and lower annular plates disposed at about the levels of said top and bottom surfaces of said rotor, respectively, and 12 to 36 vertical guide plates arranged at circumferentially spaced locations between said annular plates, said mixture of air and liquid emanating from said impeller chambers flowing outwardly between said annular plates and being additionally mixed and directed toward said wall of said container by said vertical guide plates; the inner diameter of both said annular plates being from 1 to 6 mm greater than said maximum outer diameter of said rotor, and the outer diameter of both said annular plates being at least between about 1.5 and 2 times said maximum outer diameter of said rotor; each of said vertical guide plates of said stator being oriented nonradially of said rotor in the direction of rotation thereof and making an angle of 25* to 35* with a respective radial plane which includes the inner edge of that guide plate; and the locus of said inner edges of said guide plates being at a 0.5 to 3 mm spacing from the locus of the apices of said vanes of said rotor.