FLOATING AERATOR

• US 3,572,658 A
• Filed: 01/15/1968
• Issued: 03/30/1971
• Est. Priority Date: 01/15/1968
• Status: Expired due to Term

• Current Assignee: Aqua-Aerobic Systems Incorporated (Metawater Company Limited)
• Original Assignee: Richard B. Ravitts
• Inventors: Ravitts, Richard B.
• Application Number:
  US04/697,681
• Time in Patent Office: 1,170 Days
• US Class Current: 261/36.1
• CPC Class Codes: B01F 23/23421 the stirrers rotating about a vertical axis
• CPC Class Codes: B01F 27/80 with stirrers rotating about a substantially vertical axis
• CPC Class Codes: B01F 33/503 Floating mixing devices
• CPC Class Codes: C02F 3/16 the aerator having a vertical axis
• CPC Class Codes: Y02W 10/10 Biological treatment of water, waste water, or sewage
• CPC Class Codes: Y10S 261/71 Sewage aerators; rotating

Abstract

A floating liquid aerator includes an axial flow propeller rotated by an electric motor and disposed within a tubular throat to pump water from a pond upwardly through the throat and against a rotatable diffuser which slings the water outwardly for interface contact with the surrounding atmosphere. Telescoped into the throat and over the propeller is a tubular ring duct which divides the upwardly flowing column of water into a central core and a surrounding outer cylinder to prevent the formation of a vortex within the throat and thereby increase the pumping efficiency of the aerator. More nearly laminar flow across the propeller is produced by a series of stationary infuser vanes positioned beneath the ring duct to feed the inflowing water inwardly to the propeller at a controlled angle. Increased transfer of oxygen to the water is achieved by introducing air into the upwardly flowing water, the air being admitted into the outer cylinder of water in the area of the ring duct to avoid cavitation at the propeller.

Claims

1. In a liquid aerator of the type comprising a float adapted to be supported buoyantly in a body of liquid and having a vertically extending opening formed therethrough, an upright tubular throat telescoped into said opening with its lower end projecting below the float for immersion in the liquid and with its upper end opening above the float for the discharge of liquid pumped upwardly through the throat, a power rotated shaft carried by said float and extending axially into said throat, a propeller fixed to and rotatable with said shaft to pump liquid upwardly through said throat in response to rotation of said shaft, said propeller comprising a series of angularly spaced and twisted blades radiating outwardly from said shaft and having tips spaced radially inwardly from said throat, and a rotatable diffuser fixed to said shaft above said propeller and said float for impinging against liquid moving upwardly through said throat and for slinging the liquid outwardly across the top of the float, the improvement in said aerator comprising, a tubular ring duct telescoped into said throat and over said propeller with its interior wall surrounding the tips of said blades, said ring duct being spaced inwardly from the walls of said throat to divide the liquid flowing into the throat into a central core passing through the ring duct and an outer cylinder surrounding the core and passing through the space between the ring duct and the throat, and a series of angularly spaced infuser vanes extending radially beneath said ring Duct and anchored in stationary positions, said infuser vanes being twisted by an amount correlated with the twist of said propeller blades to deflect the liquid into the latter at a controlled angle.

2. An aerator as defined in claim 1 further including at least one air conduit having an upper end vented to the atmosphere above the liquid, said conduit extending downwardly along said throat and having a lower end opening into the space between said ring duct and said throat to introduce air into the outer cylinder of liquid.

3. In a liquid aerator, the combination of, a support having an upright tubular throat adapted for immersion in a body of liquid at its lower end and defining an opening at its upper end for the discharge of liquid pumped upwardly through the throat, a power rotated shaft carried by said support and extending axially into said throat, a propeller fixed to and rotatable with said shaft within said throat to pump liquid upwardly through the throat in response to rotation of the shaft, said propeller comprising a series of angularly spaced blades radiating outwardly from said shaft and having tips spaced radially inwardly from said throat, tubular ring duct telescoped into said throat and over said propeller with the ring duct being disposed entirely within said throat and with the blades being disposed entirely within the ring duct, the interior wall of said ring duct surrounding the tips of said blades from the top to the bottom thereof and defining a primary flow passage through which a column of liquid is drawn upwardly by the blades as the latter rotate, and said ring duct being spaced radially inwardly from said throat and defining with the latter a secondary flow passage through which a second column of liquid is induced to flow as a result of the liquid being drawn upwardly through said primary passage.

4. An aerator as defined in claim 3 in which said throat and said ring duct are of cylindrical cross section and are coaxial with said shaft, the radial spacing between said ring duct and said throat being greater than the radial spacing between the ring duct and the tips of said blades.

5. An aerator as defined in claim 3 further including a series of angularly spaced infuser vanes extending radially across said primary flow passage beneath said propeller and stationarily anchored within said throat to direct upwardly flowing liquid to said propeller blades at a controlled angle.

6. An aerator as defined in claim 5 in which each propeller blade is twisted about its longitudinal centerline with the attack angle of the blade decreasing progressively from its root to its tip, and each of said infuser vanes being twisted about its longitudinal centerline in accordance with the twist of each propeller blade to direct the liquid to the latter at a controlled angle along the length of the propeller blade.

7. An aerator as defined in claim 3 further including at least one air conduit having an upper end vented to the atmosphere above the liquid, said conduit extending downwardly along the outer side of said throat and communicating at its lower end with said secondary flow passage to introduce air into said second column of water.

8. In a liquid aerator, the combination of, a support having an upright tubular throat adapted for immersion in a body of liquid at its lower end and defining an upright passage through which liquid is pumped upwardly for discharge at the upper end of the throat, a power rotated shaft carried by said support and extending axially into said throat, a propeller fixed to and rotatable with said shaft within said throat to pump a column of liquid upwardly through said passage in response to rotation of said shaft, said propeller having a hub fixed to said shaft and having a series of angularly spaced blades radiating outwardly from the hub with their roots fixed to the hub and with their tips spaced radially inwardly from said throat, each blade being twisted with a progressively decreasing attack aNgle from its root to its tip and a series of angularly spaced infuser vanes joined together at their inner ends and radiating outwardly toward said throat beneath said propeller blades with their outer ends fixed to said throat, each of said infuser vanes being twisted with a progressively decreasing attack angle from its inner end to its outer end to direct the flow of liquid to each propeller blade at an angle which constantly changes along the length of the blade in accordance with changes in the attack angle of the blade.

9. An aerator as defined in claim 8 in which the difference in the attack angle between any two points along the length of each propeller blade is equal to the difference in the attack angle between two corresponding and underlying points along the length of each infuser vane.

10. An aerator as defined in claim 8 further including a tubular ring duct telescoped over said propeller and into said throat and fixed to the latter above said infuser vanes, said ring duct surrounding the tips of said propeller blades and being spaced radially inwardly from said throat to establish a selected pattern of liquid flow to the blades in opposition to the vortical flow pattern normally created in the liquid.