Apparatus for mixing a gas and a liquid

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 inlet passage for air;
• 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 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 having a section extending beyond the second end of said outer housing;
• a propeller attached to said section of the inner tube means for rotation therewith, said propeller having a transverse dimension in a plane passing through said propeller and generally perpendicularly through the axis of said inner tube means, said propeller being adapted to be placed in a liquid and to propel the liquid in which the propeller rotates;
• inlet means for admitting a gas into said inner tube means, said inlet means being formed in said inner tube means;
• a diffusion tube forming a portion of said section of said inner tube means which extends beyond the second end of said housing, said diffusion tube extending beyond said propeller, said diffusion tube having an open end at the second end of said inner tube means forming an outlet from said diffusion tube for injecting a gas passing through said inner tube means into a liquid in which the propeller is placed, said diffusion tube having a length at least fifty percent of the length of the transverse dimension of the propeller to dispose said open end of said diffusion tube a distance away from said propeller at least fifty percent of the length of the transverse dimension of the propeller whereby the propeller can rotate through a liquid substantially free of gas bubbles injected into the liquid through the open end of said diffusion tube when the axis of said inner tube means is disposed at an acute angle relative to the horizontal;
• and
• means for preventing the formation of a vortex above said propeller in liquid being propelled by said propeller when said inner tube means is disposed at an acute angle relative to the horizontal, said last-mentioned means including a shield attached to an outer surface of the outer housing adjacent its second end and extending over a portion of the outer surface of said outer housing immediately above the propeller.

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 inlet passage for air;
• 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 having a section extending beyond the second end of said outer housing;
• a propeller attached to said section of the inner tube means for rotation therewith, said propeller having a transverse dimension in a plane passing through said propeller and generally perpendicularly through the axis of said inner tube means, said propeller being adapted to be placed in a liquid and to propel the liquid in which the propeller rotates;
• inlet means for admitting a gas into said inner tube means, said inlet means being formed in said inner tube means;
• a diffusion tube forming a portion of said section of said inner tube means which extends beyond the second end of said housing, said diffusion tube extending beyond said propeller, said diffusion tube having an open end at the second end of said inner tube means forming an outlet from said diffusion tube for injecting a gas aspirated through said inner tube means into a liquid in which the propeller is placed, said aspiration being caused by liquid propelled past said open end by the rotation of said propeller, said diffusion tube having a length at least fifty percent of the length of the transverse dimension of the propeller to dispose said open end of said diffusion tube a distance away from said propeller at least fifty percent of the length of the transverse dimension of the propeller whereby the propeller can rotate through a liquid substantially free of gas bubbles injected into the liquid through the open end of said diffusion tube when the axis of said inner tube means is disposed at an acute angle relative to the horizontal;
• and
• means for preventing the formation of a vortex in the liquid above the propeller, said vortex prevention means including a shield attached by a plurality of fins to said outer housing adjacent its second end, said fins extending radially from the outer surface of said outer housing adjacent its second end, each fin having a distal end, said shield having a curvilinear configuration and an inner surface attached to the distal ends of said fins to hold said shield in a spaced relationship from said outer housing, said shield having opposite ends and a lengthwise dimension extending between the ends generally in the direction of the longitudinal dimension of said outer housing and a circumferential dimension extending in an arc less than 360.degree. generally around the longitudinal axis of said inner tube means, one of the ends of said shield extending over said propeller.