US3904714A - Low-speed mechanical aerator impeller - Google Patents

Low-speed mechanical aerator impeller Download PDF

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Publication number
US3904714A
US3904714A US40110073A US3904714A US 3904714 A US3904714 A US 3904714A US 40110073 A US40110073 A US 40110073A US 3904714 A US3904714 A US 3904714A
Authority
US
United States
Prior art keywords
impeller
shroud
edge
blade
inlet
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
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English (en)
Inventor
Thomas C Rooney
Robert E Crandall
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens Water Technologies Holding Corp
Original Assignee
Rexnord Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Rexnord Inc filed Critical Rexnord Inc
Priority to US40110073 priority Critical patent/US3904714A/en
Priority to GB3802874A priority patent/GB1441502A/en
Priority to FR7431118A priority patent/FR2257799A1/fr
Priority to BE148572A priority patent/BE819964A/fr
Priority to AU73490/74A priority patent/AU482080B2/en
Priority to IT6986074A priority patent/IT1030060B/it
Priority to SE7412092A priority patent/SE7412092L/xx
Priority to NL7412642A priority patent/NL7412642A/xx
Priority to JP49110381A priority patent/JPS5852686B2/ja
Application granted granted Critical
Publication of US3904714A publication Critical patent/US3904714A/en
Assigned to ENVIREX INC., A CORP. OF DE reassignment ENVIREX INC., A CORP. OF DE ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: REXNORD, INC.
Assigned to WILMINGTON TRUST COMPANY AND WADE, WILLIAM J., TRUSTEE reassignment WILMINGTON TRUST COMPANY AND WADE, WILLIAM J., TRUSTEE SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ENVIREX INC.
Assigned to WADE WILLIAM J. reassignment WADE WILLIAM J. RELEASED BY SECURED PARTY (SEE DOCUMENT FOR DETAILS). RELEASE BY SECURED PARTY, PREVIOUSLY RECORDED ON AUGUST 25, 1988 REEL 4976 FRAME 352 Assignors: WILMINGTON TRUST COMPANY
Assigned to ENVIREX INC., A CORP OF DE reassignment ENVIREX INC., A CORP OF DE ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: WILLIAM J. WADE, AS TRUSTEE
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00—Biological treatment of water, waste water, or sewage
    • C02F3/02—Aerobic processes
    • C02F3/12—Activated sludge processes
    • C02F3/14—Activated sludge processes using surface aeration
    • C02F3/16—Activated sludge processes using surface aeration the aerator having a vertical axis
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
    • B01F23/20—Mixing gases with liquids
    • B01F23/23—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids
    • B01F23/234—Surface aerating
    • B01F23/2342—Surface aerating with stirrers near to the liquid surface, e.g. partially immersed, for spraying the liquid in the gas or for sucking gas into the liquid, e.g. using stirrers rotating around a horizontal axis or using centrifugal force
    • B01F23/23421—Surface aerating with stirrers near to the liquid surface, e.g. partially immersed, for spraying the liquid in the gas or for sucking gas into the liquid, e.g. using stirrers rotating around a horizontal axis or using centrifugal force the stirrers rotating about a vertical axis
    • B01F23/234211—Stirrers thereof
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/18—Rotors
    • F04D29/181—Axial flow rotors
    • F04D29/183—Semi axial flow rotors
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W10/00—Technologies for wastewater treatment
    • Y02W10/10—Biological treatment of water, waste water, or sewage

Definitions

  • ABSTRACT A low speed impeller of large size and pumping capacity comprises a conical shroud and 3, 4 or 5 flat blades projecting therefrom. The shroud and blades are disposed and proportioned to provide a wider operating range and are particularly adapted for fabrication of flat plates which are welded directly to the shroud.
  • Impellers in general are designed for inducing an axial flow or a radial flow, the latter including centrifugal impellers. If the discharge is partially axial and partially radial, the impeller is a mixed flow impeller.
  • Impellers have some number of vanes or blades projecting from the hub which is mounted on the shaft which supports and rotates the impeller.
  • the efficiency of the blades is generally improved by a shroud around the hub which blocks off the center space and directs the flow smoothly past or around the hub.
  • the hub and shroud may of course comprise the same structure.
  • Each blade of an impeller has a boundary edge which includes the portion where it is attached to the hub or where it meets the shroud.
  • the boundary edge also has three other portions which are generally defined in terms of impeller rotation and the direction of the flow, viz. the leading edge, the inlet edge, and the outlet edge.
  • One method of aerating waste water or industrial wastes for its biological treatment is by the use of a ro tating impeller located at the surface of the water.
  • Such impellers are generally fixed on the lower end of the vertical output shaft of a motor driven gear reducer which is supported either by a fixed structure or by floats or pontoons.
  • a high speed aerator is one which generally includes an axial flow impeller in a vertical draft tube with an upper member which deflects the water in a circular pattern having a considerable upward trajectory. In terms of pumping a given quantity of water per horsepower or current consumption, are of lower first cost but of less efficiency.
  • Low speed aerators are generally of two types and are driven by motors or engines of up to 175 hp.
  • One type churns large quantities of water at the surface for aeration.
  • the other type is designed to draw as much water as desired from as deep a level below the unit as is necessary to effect mixing and scouring of the bottom of the basin in which the unit is operating.
  • the water is then discharged horizontally to create a large flow across the surface of the water toward the wall of the tank.
  • This up-draft type in a fixed structure might include a large draft tube having an inlet near the floor of the tank.
  • These units generally include an axial flow impeller and the discharge may have a vertical component similar to that of the high speed aerator.
  • the known prior art impellers exhibit a wide range of pumping capacity over a narrow range of submergence. This means that in terms of overall tank design, the tank must be provided with impossibly long weirs in order to hold the water level within the narrow range allowed by the impeller. Alternatively, mechanically operated weirs have been provided to maintain a constant level.
  • the object of the present invention is to provide a more stable impeller having the desired pumping capacity and submergence range which is required for and characteristic of a typical biological treatment tank utilizing surface aeration.
  • the impeller of the present invention has a 45 conical shroud and three, four or five flat blades which ex tend downwardly therefrom so that their inlet edges are substantially below the apex of the shroud.
  • the angle between the leading edge of each blade and the impeller axis is in the order of 30.
  • the overall height of the impeller is in the order of two-thirds of its diameter.
  • a prime characteristic of the impeller is its wide band submergence limits for a typical perfor mance range.
  • FIG. 1 is a plan view of a representative biological waste treatment tank with a bridge mounted mechanical aerator.
  • FIG. 2 is a central vertical cross section of the tank shown in FIG. 1.
  • FIG. 3 is a plan view of the blades of the impeller. That is, the view is that of the blades looking down wardly.
  • the drive shaft is shown in section and the outline of the shroud is shown in broken lines.
  • FIG. 4 is a side elevation of the impeller of FIG. 3.
  • FIG. 5 is a vertical elevation of one-half of the impeller taken on line 55 of FIG. 3.
  • FIG. 6 shows a blade of the impeller with additional marginal portions which may be provided in accordance with the invention.
  • a representative square tank 8 is shown in FIGS. 1 and 2 and includes the baffled inlet pipe 9 and the outlet weir 10 which controls the elevation of the water level within the tank.
  • One of the four side walls of the tank includes the weir trough 11 which extends the length of weir 10 and includes the effluent pipe 12.
  • the mechanical aerator 13 is mounted on the bridge 14 at the center of the tank and includes the upper drive motor 15, the gear reducer 16 having an output shaft 17 extending downwardly therefrom and below bridge 14 and the impeller 21 which is mounted on the lower end of shaft 17 for rotation therewith at the surface of the tank contents.
  • Impeller 21 comprises the shroud 22, the several blades 23 and a hub, not shown in detail, by which the impeller is removably secured to shaft 17.
  • the hub and shroud 22 may be of any suitable construction.
  • a feature of the invention resides in the fact that blades 23 are of flat plates which may be welded at their inner boundaries 24 directly to shroud 22.
  • Shroud 22 is in the form of a right circular 45 cone and as such includes a circular upper end which is bounded by the upper edge 22a.
  • the height of the shroud from its lower apex 22b to its upper end is thus equal to the radius of the upper edge 22a.
  • the shroud may be truncated as shown such that it has a relatively small circular lower end 22c.
  • each blade 23 forms an angle in the order of 30 with the downward projection A of the axis of shaft 17 and the blades are equally spaced around the axis.
  • the intersection of the plane of each blade 23 and the axis of the impeller is located at the upper end of shroud 22 such that the plane referred to may be further defined as a plane which includes a radius R of shroud '22 at its upper end and defines therewith an angle of 60.
  • the leading edge 25 of blade 23 extends from shroud 22 to a lower elevation approximately 033R below apex 22b and the outlet edge 27 from edge 22a of shroud 22 to a point approximately at the elevation of apex 22b and radius R.
  • the inlet edge includes two portions. Portion 26a extends horizontally at said lower elevation from leading edge 25 and inlet edge portion 26b extends there from to the lower end of outlet edge 27 which has been defined.
  • FIG. 6 shows by way of example the additional areas which may be provided in accordance with the invention. This may include the triangular portion 31 such that the leading edge 25a has a slight negative rake respecting its rotation.
  • the trailing section 32 may be added such that the outlet edge 27a extends to a radius of 1.2R as shown, but not appreciably greater than l.5R.
  • Impeller 21 could also be provided with four similar blades and possibly with five blades. However, the blades extend 90 or more around the shroud 22 and the overlapping of the blades is thought to make six or more blades impracticable.
  • the tank 8 may be considered typical of a biological treatment tank as a single unit.
  • the tank as shown is feet X 80 feet X 20 feet and the water level to the weir 10 is 18 feet.
  • Such a tank would accommodate a normal flow (Q) for a typical waste in the order of 7,500 gallons per minute.
  • Minimum and maximum flows might be 2,500 gpm. and 22,000 gpm. respectively.
  • impeller 21 would require a weir length of only 29 feet because of its submergence range.
  • a weir length of somewhere between 80 feet and 120 feet may be required. While a weir is an especially inexpensive device, the necessity of providing a weir of such additional length for tank 8 would require extending the weir trough 11 around the tank as shown in FIG. 2 by the broken line 11a and would be a considerable complication.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Water Supply & Treatment (AREA)
  • Hydrology & Water Resources (AREA)
  • Environmental & Geological Engineering (AREA)
  • Microbiology (AREA)
  • Biodiversity & Conservation Biology (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Mixers Of The Rotary Stirring Type (AREA)
  • Aeration Devices For Treatment Of Activated Polluted Sludge (AREA)
US40110073 1973-09-26 1973-09-26 Low-speed mechanical aerator impeller Expired - Lifetime US3904714A (en)

Priority Applications (9)

Application Number Priority Date Filing Date Title
US40110073 US3904714A (en) 1973-09-26 1973-09-26 Low-speed mechanical aerator impeller
GB3802874A GB1441502A (en) 1973-09-26 1974-08-30 Low speed mechanical aerator impeller
FR7431118A FR2257799A1 (fr) 1973-09-26 1974-09-13
BE148572A BE819964A (fr) 1973-09-26 1974-09-16 Turbine d'aeration mecanique a faible vitesse
AU73490/74A AU482080B2 (en) 1973-09-26 1974-09-19 Low speed mechanical aerator impeller
IT6986074A IT1030060B (it) 1973-09-26 1974-09-23 Elica per l aerazione meccanica a bassa velocita, particolarmente di acque di scarico e rifiuti industriali
SE7412092A SE7412092L (fr) 1973-09-26 1974-09-25
NL7412642A NL7412642A (nl) 1973-09-26 1974-09-25 Mechanische beluchtingswaaier van geringe eid.
JP49110381A JPS5852686B2 (ja) 1973-09-26 1974-09-25 タテガタコンゴウリユウ ハネグルマ

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US40110073 US3904714A (en) 1973-09-26 1973-09-26 Low-speed mechanical aerator impeller

Publications (1)

Publication Number Publication Date
US3904714A true US3904714A (en) 1975-09-09

Family

ID=23586299

Family Applications (1)

Application Number Title Priority Date Filing Date
US40110073 Expired - Lifetime US3904714A (en) 1973-09-26 1973-09-26 Low-speed mechanical aerator impeller

Country Status (8)

Country Link
US (1) US3904714A (fr)
JP (1) JPS5852686B2 (fr)
BE (1) BE819964A (fr)
FR (1) FR2257799A1 (fr)
GB (1) GB1441502A (fr)
IT (1) IT1030060B (fr)
NL (1) NL7412642A (fr)
SE (1) SE7412092L (fr)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4147437A (en) * 1975-06-04 1979-04-03 Procedes Sem Mixer blade
US4522766A (en) * 1981-11-20 1985-06-11 Satoshi Sunada Gas-liquid contacting device
US4650342A (en) * 1982-10-28 1987-03-17 R. Goodwin International Ltd. Agitating particulate solids
US4652382A (en) * 1984-10-19 1987-03-24 International Waste Water Reclamation Technologies, Inc. Process and apparatus for continuously treating sewage wastewater by chemical oxidation
US4943165A (en) * 1989-06-16 1990-07-24 United States Pollution Control Company, Inc. Sludge stabilizing method and apparatus
US5040900A (en) * 1989-06-16 1991-08-20 United States Pollution Control Company, Inc. Sludge stabilizing method and apparatus
US6224041B1 (en) 1999-05-28 2001-05-01 Smith & Loveless, Inc. Splash plate structure for aerators
US20040188334A1 (en) * 1998-09-28 2004-09-30 Mcwhirter John R. Novel biochemical oxidation system
US20160279585A1 (en) * 2015-03-25 2016-09-29 Schlumberger Technology Corporation Blender for mixing and pumping solids and fluids and method of use thereof
US9962665B2 (en) 2012-06-20 2018-05-08 Philadelphia Mixing Solutions, Ltd. High efficiency, non-ragging, formed axial impeller
WO2019221610A1 (fr) * 2018-05-16 2019-11-21 Tore Hystad Pompe centrifuge

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010042411A (ja) * 2009-09-25 2010-02-25 Penn State Research Foundation 表面曝気羽根車

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2072944A (en) * 1934-12-21 1937-03-09 Chicago Pump Co Aerator
US2346366A (en) * 1941-12-29 1944-04-11 Lewis H Durdin Mechanical aerator
US2354653A (en) * 1940-06-11 1944-08-01 Gen Electric Impeller
US3323782A (en) * 1962-05-07 1967-06-06 Carves Simon Ltd Aeration of liquids
US3470092A (en) * 1967-05-08 1969-09-30 Degremont Sa System for the purification of waste waters

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2072944A (en) * 1934-12-21 1937-03-09 Chicago Pump Co Aerator
US2354653A (en) * 1940-06-11 1944-08-01 Gen Electric Impeller
US2346366A (en) * 1941-12-29 1944-04-11 Lewis H Durdin Mechanical aerator
US3323782A (en) * 1962-05-07 1967-06-06 Carves Simon Ltd Aeration of liquids
US3470092A (en) * 1967-05-08 1969-09-30 Degremont Sa System for the purification of waste waters

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4147437A (en) * 1975-06-04 1979-04-03 Procedes Sem Mixer blade
US4522766A (en) * 1981-11-20 1985-06-11 Satoshi Sunada Gas-liquid contacting device
US4650342A (en) * 1982-10-28 1987-03-17 R. Goodwin International Ltd. Agitating particulate solids
US4652382A (en) * 1984-10-19 1987-03-24 International Waste Water Reclamation Technologies, Inc. Process and apparatus for continuously treating sewage wastewater by chemical oxidation
US4943165A (en) * 1989-06-16 1990-07-24 United States Pollution Control Company, Inc. Sludge stabilizing method and apparatus
US5040900A (en) * 1989-06-16 1991-08-20 United States Pollution Control Company, Inc. Sludge stabilizing method and apparatus
US20040188334A1 (en) * 1998-09-28 2004-09-30 Mcwhirter John R. Novel biochemical oxidation system
US6224041B1 (en) 1999-05-28 2001-05-01 Smith & Loveless, Inc. Splash plate structure for aerators
US9962665B2 (en) 2012-06-20 2018-05-08 Philadelphia Mixing Solutions, Ltd. High efficiency, non-ragging, formed axial impeller
US11241663B2 (en) 2012-06-20 2022-02-08 Philadelphia Mixing Solutions, Ltd. High efficiency, non-ragging, formed axial impeller
US20160279585A1 (en) * 2015-03-25 2016-09-29 Schlumberger Technology Corporation Blender for mixing and pumping solids and fluids and method of use thereof
US10173184B2 (en) * 2015-03-25 2019-01-08 Schlumberger Technology Corporation Blender for mixing and pumping solids and fluids and method of use thereof
WO2019221610A1 (fr) * 2018-05-16 2019-11-21 Tore Hystad Pompe centrifuge

Also Published As

Publication number Publication date
AU7349074A (en) 1976-03-25
IT1030060B (it) 1979-03-30
BE819964A (fr) 1975-01-16
FR2257799A1 (fr) 1975-08-08
GB1441502A (en) 1976-07-07
JPS5059858A (fr) 1975-05-23
JPS5852686B2 (ja) 1983-11-24
SE7412092L (fr) 1975-03-27
NL7412642A (nl) 1975-04-01

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Owner name: WADE, WILLIAM J., RODNEY SQUARE NORTH, WILMINGTON

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Free format text: RELEASED BY SECURED PARTY;ASSIGNOR:WILMINGTON TRUST COMPANY;REEL/FRAME:005527/0321

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Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:WILLIAM J. WADE, AS TRUSTEE;REEL/FRAME:005518/0862

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