Aeration propeller and apparatus

A non-fouling propeller mechanism for use with an aeration apparatus comprising:

• a support tube for attachment to an end of a rotatable air injection tube of an aeration apparatus;
• a plurality of propeller blades attached to the outer surface of said support tube;
• each propeller blade having a leading end, a tail end, an outer edge, and an impelling surface, the outer edge at the leading end extending outwardly from the outer surface of said support tube at an angle less than 45.degree., said impelling surface facing the direction in which said propeller mechanism is adapted to rotate, said impelling surface having a rake at a given axial position along a respective propeller blade defined by the angle at which the impelling surface is disposed with respect to a radius extending normal from the axis of the support tube, said rake changing to a more positive rake from the axial position at the leading end to the axial position at the tail end;
• said support tube having a diffusion section extending below the lowermost extent of said propeller blades a predetermined distance sufficient that air bubbles ejected from an open outlet end of said support tube do not intermix with the water through which said propeller blades are rotated;
• and
• a plurality of plate members extending below said air outlet end for breaking up air bubbles exiting said air outlet end and for causing radial flow thereof.

A propeller mechanism for use with an aeration apparatus comprising:

• a support tube for attachement to an end of a rotatable air injection tube of an aeration apparatus;
• means for inducing a turbulent axial flow of liquid in which said propeller is rotated, said inducing means including a plurality of propeller blades attached to an outer surface of said support tube and having an impelling surface with a rake at a given axial position along a respective propeller blade defined by the angle at which the impelling surface is disposed with respect to a radius extending normal from the axis of the support tube, said rake changing to a more positive rake from the axial position at the leading end to the axial position at the tail end;
• means for injecting air bubbles a sufficient distance below said propeller blades such that said propeller blades rotate in water free of air bubbles when said support tube is held at an acute angle relative to the horizontal, said air injection means including a diffusion section of said support tube extending a predetermined distance below a lowermost extent of said propeller blades and having an open air outlet end;
• means for breaking up air bubbles exiting said air outlet end and for causing a radial flow of said air bubbles and water, said last-mentioned means including a plurality of plates extending axially below and radially outward from said support tube;
• and
• means for reestablishing an axial flow of air bubbles and water, said last-mentioned means including a lowermost portion of at least one of said blades being bent backward in the direction in which said propeller mechanism is intended to rotate.

An apparatus for mixing a gas and a liquid comprising:

• an outer housing having a hollow interior, opposite first and second ends, and a longitudinal dimension extending between the ends;
• inner tube means for defining an air inlet passage;
• said inner tube means being mounted for rotary motion about its axis within the hollow interior of said outer housing;
• motor means attached to said outer housing adjacent the first end thereof and drivingly coupled to a first end of said inner tube means for rotating said inner tube means;
• said inner tube means including a support tube extending beyond the second end of said outer housing;
• a plurality of propeller blades attached to said support tube for rotation therewith, said propeller blades having a maximum transverse dimension in a plane passing through said propeller blades and generally perpendicularly through the axis of said support tube, said propeller blades being adapted to be placed in a liquid and to propel the liquid in which the propeller rotates;
• each propeller blade having a leading end, a tail end, an outer edge and an impelling surface facing the direction in which said inner tube means is rotated, the outer edge at the leading end extending outwardly from the outer surface of said support tube at an angle less than 90.degree., and said impelling surface having a rake at a given axial position along a respective propeller blade defined by the angle at which the impelling surface is disposed with respect to a radius extending normal from the axis of the support tube, said rake changing to a more positive rake from the axial position at the leading end to the axial position at the tail end;
• inlet means for admitting a gas to the hollow interior of said inner tube means, said inlet means being formed in said inner tube means;
• and
• said support tube having a diffusion section extending below the lowermost extent of said propeller blades, said support tube having an open air outlet end at the second end of said inner tube means for injecting a gas passing through the hollow interior of said inner tube means into a liquid in which the support tube is placed.