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US 6,142,458 AGranted
Mixing system for dispersion of gas into liquid media
AssigneeGeneral Signal Corporation
InventorRichard A Howk
Life of this patent
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AssigneeGeneral Signal Corporation
InventorRichard A Howk
Estimating the term…
In order to sparge gas into a liquid or liquid suspension in a tank wherein a principally axial flow pattern downwardly towards the bottom of the tank and then upwardly along the side wall of the tank returning axially downward is established by an axial flow impeller, a disc of a diameter less than the diameter of the impeller is spaced axially therefrom in the direction of the outlet flow towards the bottom of the tank from the impeller so as to turn the axial flow, radially, thereby establishing a pressure gradient which prevents the collection of gas released by a sparge between the disc and the bottom of the tank and flooding of the impeller. The gas is released in the axial flow from the tip region of the impeller thereby facilitating the shearing of the gas into fine bubbles promoting mass transfer of the gaseous phase into the liquid phase in the tank. Since flooding is inhibited, as much as six times the volume of gas (gas rate) can be handled as may be the case without the disc.
A mixing system for dispersing a gas into a liquid which comprises an axial flow impeller having blades rotatable about an axis to provide said flow principally along said axis, a member presenting a surface opposing the axial flow from said impeller, said surface extending radially from said impeller and being spaced axially away from said impeller, a sparge releasing gas into a region radially outward of said member in the axial flow from said impeller, said spacing from and said radial extent of said surface with respect to said impeller being sufficiently proximate to said blades across a sufficient radial extent of said blades to turn the axial flow of said impeller into radial flow across said blades of a velocity sufficient to inhibit the collection of gas on said impeller and the flooding thereof by said gas.
A mixing system for dispersing a gas into a liquid which comprises an axial flow impeller having blades rotatable about an axis to provide said flow principally along said axis, a member presenting a surface opposing the axial flow of said impeller, said surface extending radially of said impeller and being spaced axially away from said impeller and inwardly from the tips of said blades, a sparge releasing gas into a region radially outwardly of said member, and said radial extent of said surface with respect to said impeller and the proximity of said surface to said blades being sufficient to turn the axial flow of said impeller into radial flow of a velocity sufficient to inhibit the collection of gas on said impeller and the flooding thereof by said gas, and wherein said impeller has a diameter measured across the path of the tips of the blades thereof as said impeller rotates, said axial spacing of said surface from said impeller measures from the midline of said impeller being in the range of about 5% to 10% of the diameter of the impeller and the radial extent of said surface being about 50% to 85% of the diameter of said impeller.
Dependencies are inferred from the claim text.