Patent ID: 8434931

Claim:
An impeller used for mixing a gas or mixture of gases into a liquid, wherein the liquid is in a vessel having a capacity of less than about 50 milliliters, wherein a gas or mixture of gases is introduced into said vessel above said liquid and the gas is mixed into said liquid by the impeller, said impeller being characterized by a longitudinal axis around which the impeller rotates and said impeller comprising a support shaft having a top portion which is suitable for connecting to a driver to cause rotation of the impeller and a bottom portion, and an impeller blade connected to the bottom portion of the support shaft, wherein the blade has front and back primary surfaces which define a thickness of the blade, top and bottom exterior edges which define a length of the impeller blade and two side exterior edges which define a width of the impeller blade the top, bottom and side edges together defining an area of said primary surface of the impeller blade, the top exterior edge of said impeller blade being connected to the bottom portion of said shaft the blade has an opening defined by top, bottom and side interior edges of the blade extending through the blade from the front to the back surface said opening extending across the rotational axis of the impeller, wherein the opening comprises no more than 60 percent of the area of the primary surface of the impeller blade, wherein said top and bottom exterior edges are the same size, and wherein said impeller efficiently mixes said gas or mixture of gases into said liquid; wherein the opening extends for a length which is from 20 to 70 percent of the length of the blade and for a width which is from 30 to 80 percent of the width of the blade; and wherein the impeller has a blade length in the range of 1 to 5 cm and a blade width of 0.5 to 2 cm and a thickness of 0.5 to 2 mm.