Liquid aerating apparatus

Apparatus for aerating a liquid comprising a drive shaft having therein an aeration fluid passage in communication with an aeration fluid source;

• means journaling said drive shaft for rotation about an axis;
• drive means coupled to said drive shaft for rotating the drive shaft;
• and a propeller fixed to said drive shaft for rotation therewith, said propeller being immersible in said liquid and having a plurality of helically extending blades each of which has a root, a leading edge, a trailing edge, and a tip, each of said blades being joined at its root to said drive shaft and having an airfoil profile between said edges defining a suction side of said blade and a thrust side of said blade whereby rotation of said blade in said liquid produces a negative pressure on said suction side which is greatest at a zone adjacent said trailing edge, said zone being radially inward of said blade tip and more than half the distance from said axis to said blade tip, each of said blades having an internal chamber communicating with said aeration fluid passage and terminating radially inward of said blade tip, each of said chambers having a primary aeration fluid outlet port at said zone, whereby rotation of said propeller in said liquid causes the aeration fluid to be drawn into the chamber of each of said blades through said passage and discharged into said liquid through said primary outlet port, none of said blades having an aeration port in communication with said aeration fluid passage closer to said axis than about half the distance of said blade from said axis to its tip, and none of said blades having an aeration port the area of which is greater than that of said primary aeration port.