APPARATUS FOR MIXING GASSES AND LIQUIDS

Abstract

An apparatus for mixing gas and liquid is disclosed. The apparatus may have a plurality of blades rotated about a common shaft. The blades may have a forward portion, which cuts through a liquid, and a trailing portion, which forms the leading part of a gas cavity. The gas cavity is in communication with a gas inlet and the bulk fluid. As the blades pass through a liquid, a reduced pressure zone is formed immediately behind the blade. The reduced pressure zone allows air to be aspirated from the gas inlet into the gas cavity adjacent to the blade. Gas in the gas cavity is sheared into discrete bubbles and transferred to the liquid by the action of the trailing blade wake currents.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a horizontally mounted inline mixer with inline blades for creating low-pressure zones for air entrainment in a liquid according to one embodiment of the present invention.

FIG. 2 illustrates a side-view of the inline mixer of FIG. 1 according to one embodiment of the present invention.

FIG. 3 is a cross-section of a inline blade along section A-A of FIG. 1, showing a forward portion and gas cavity according to one embodiment of the present invention.

FIG. 4 illustrates two inline mixers aerating an activated sludge racetrack type containment vessel according to one embodiment of the present invention.

FIG. 5 illustrates a mixer on a vertically mounted shaft with inline blades of increasing length according to one embodiment of the present invention.

FIG. 6 illustrates a rear-view of a inline blade showing the gas cavity of the blade according to one embodiment of the present invention.

FIG. 7 illustrates a rear-view of a inline blade partially covered by a back plate according to one embodiment of the present invention.

FIG. 8 illustrates a mixer with radially pumping blades in combination with a draft tube, according to one embodiment of the present invention.

FIG. 9 illustrates a plan-view of the mixer of FIG. 8 according to one embodiment of the present invention.

FIG. 10 illustrates a mixer having radially pumping blades and axially pumping blades in combination with a draft tube according to one embodiment of the present invention.

FIG. 11 illustrates a plan-view of the mixer of FIG. 10 according to one embodiment of the present invention.

FIG. 12 illustrates a combination blade capable of axially and radially pumping the liquid in combination with the draft tube according to one embodiment of the present invention. A sectional-view of a draft tube is shown.

FIG. 13 illustrates a mixer having perpendicular flow to the axis of rotation pumping blades in combination with an aspirating frame and gas inlet according to one embodiment of the present invention.

FIG. 14 illustrates a side-view of the mixer of FIG. 13 according to one embodiment of the present invention.

FIG. 15 illustrates a mixer having perpendicularly pumping blades according to one embodiment of the present invention.

FIG. 16 illustrates a mixer supported by a float having radially pumping blades attached to the float according to one embodiment of the present invention.

FIG. 17 illustrates a plan view of the mixer of FIG. 16 according to one embodiment of the present invention.

Claims

1. An apparatus for mixing gas and liquid comprising: a rotatable shaft having an axis of rotation; andat least one pumping blade at least partially submergible in the liquid and mounted on the rotatable shaft, the at least one pumping blade comprising a gas cavity adjacent to or trailing the at least one pumping blade,wherein rotation of the at least one pumping blade through the liquid causes the liquid to move in a direction substantially perpendicular to the axis of rotation of the rotatable shaft and causes the gas to be entrained in the liquid from the gas cavity.

2. An apparatus for mixing gas and liquid according to claim 1, wherein the at least one pumping blade extends radially from the rotatable shaft.

3. An apparatus for mixing gas and liquid according to claim 2, wherein the rotatable shaft is horizontally mounted above the liquid.

4. An apparatus for mixing gas and liquid according to claim 3, further comprising a gas inlet above the liquid wherein the gas inlet is located on the at least one pumping blade.

5. An apparatus for mixing gas and liquid according to claim 1, wherein the rotatable shaft comprises a central drive shaft and an outer shaft forming a gas inlet in communication with the gas cavity.

6. An apparatus for mixing gas and liquid according to claim 5, wherein the rotatable shaft is vertically arranged and partially submerged in the liquid and wherein a gas inlet extends above the liquid.

7. An apparatus for mixing gas and liquid according to claim 6, comprising a plurality of the pumping blades extending radially from the outer shaft and submerged in the liquid, wherein pumping blades deeper in the liquid are longer than pumping blades shallower in the liquid.

8. An apparatus for mixing gas and liquid comprising: a rotatable shaft;at least one radially pumping blade at least partially submerged in a liquid, the at least one radially pumping blade comprising a gas cavity adjacent to or trailing a portion of the at least one radially pumping blade;means for attaching the at least one radially pumping blade to the rotatable shaft; anda gas inlet above the liquid in communication with the gas cavity of the at least one blade.

9. An apparatus for mixing gas and liquid according to claim 8, wherein the rotatable shaft has an axis of rotation that is substantially vertical, and the at least one radially pumping blade extends in a substantially vertical direction.

10. An apparatus for mixing gas and liquid according to claim 8, wherein the at least one radially pumping blade extends in a generally diagonal direction with respect to the rotatable shaft, and a lower portion of the at least one radially pumping blade is further from the rotatable shaft than an upper portion of the at least one radially pumping blade.

11. An apparatus for mixing gas and liquid according to claim 8, wherein the gas inlet is located on a portion of the at least one blade above the liquid.

12. An apparatus for mixing gas and liquid according to claim 11, further comprising a draft tube coaxial with the rotatable shaft located adjacent and below the at least one blade.

13. An apparatus for mixing gas and liquid according to claim 12, further comprising axially pumping blades projecting radially from a lower portion of the rotatable shaft.

14. An apparatus for mixing gas and liquid according to claim 8, wherein the gas inlet is located on a portion of the at least one blade above the liquid and wherein the at least one radially pumping blade is structured and arranged to also pump axially.

15. An apparatus for mixing gas and liquid according to claim 8, wherein the means for attaching the at least one radially pumping blade to the rotatable shaft comprises a frame.

16. An apparatus for mixing gas and liquid according to claim 8, wherein the means for attaching the at least one radially pumping blade to the rotatable shaft comprises a float.

17. An apparatus for mixing gas and liquid according to claim 8, wherein the means for attaching the at least one radially pumping blade to the rotatable shaft comprises a frame attached to the shaft and the at least one blade and wherein the rotatable shaft is substantially horizontally configured and wherein the at least one radially pumping blade is substantially horizontally configured.

18. An apparatus for mixing gas and liquid according to claim 17, wherein the rotatable shaft, at least one blade and frame are completely submerged in the liquid.

19. An apparatus for mixing gas and liquid according to claim 18, wherein the gas inlet is in communication with the gas cavity of the at least one radially pumping blade through the frame.

20. An method for mixing gas and liquid comprising: providing at least one blade at least partially submerged in a liquid, the at least one blade comprising a gas cavity adjacent to or trailing a portion of the at least one blade;providing a gas inlet above the liquid in communication with the gas cavity of the at least one blade; andpropelling the at least one blade through the liquid to create a reduced pressure zone behind the at least one blade and aspirate gas from the gas inlet into the gas cavity.

21. The method for mixing gas and liquid of claim 20, wherein the at least one blade is connected to a rotatable shaft having an axis of rotation, and rotation of the at least blade through the liquid causes the liquid to move in a direction substantially perpendicular to the axis of rotation of the rotatable shaft.