US3722836A - Gas diffuser - Google Patents

Gas diffuser Download PDF

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Publication number
US3722836A
US3722836A US3722836DA US3722836A US 3722836 A US3722836 A US 3722836A US 3722836D A US3722836D A US 3722836DA US 3722836 A US3722836 A US 3722836A
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US
United States
Prior art keywords
strip
chamber
gas
cavity
diffuser
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
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English (en)
Inventor
E Savage
D Heaney
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.)
TETRA RESOURCES Inc A CORP OF
TETRA RESOURCES Inc A CORP OF DELAWARE
Original Assignee
Dravo Corp
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.)
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Publication date
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Publication of US3722836A publication Critical patent/US3722836A/en
Assigned to TETRA RESOURCES, INC., A CORP OF DELAWARE reassignment TETRA RESOURCES, INC., A CORP OF DELAWARE ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: DRAVO CORPORATION, A CORP OF PA.
Assigned to TETRA RESOURCES, INC., A CORP OF DE reassignment TETRA RESOURCES, INC., A CORP OF DE ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: DRAVO CORPORATION, A PA CORP
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
    • C02F3/20—Activated sludge processes using diffusers
    • 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
    • B01F23/231—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids by bubbling
    • B01F23/23105—Arrangement or manipulation of the gas bubbling devices
    • B01F23/2312—Diffusers
    • B01F23/23122—Diffusers having elements opening under air pressure, e.g. valves
    • 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

  • a gas diffuser for admitting gas into a body of liquid is Cl 261/64 disclosed.
  • the diffuser includes an elongated body 43 with a chamber extending inwardly from an open face [51] Int. Cl. ..B01f 3/04 th of a d a ilient tri covering the chamber and Field of sealdl 261/124, 1, 64 64 114 secured to the body so as to flex at its ends under the VT; 43, 44 urging of the pressure of gas in the chamber.
  • the body includes a pair of cavities adjacent its end walls.
  • the [56] References Cited cavities act as resonance chambers causing the gas therein to resonate with the strip as the gas stream UNlTED STATES PATENTS flows across the cavities.
  • the strip is 3,182,978 5/1965 Reilly ..26l/l24 tap r d from an intermediate portion thereof to its 2,113,615 4/1938 Farmer ends. 3,l23,305 3/1964 Eisenkraft ..289/DlG. 44
  • this back flow, or suction draws fibers and other solids in the liquid into the small holes or slits, clogging them, or the solids even enter the diffuser and block the discharge holes or slits when air pressure is again applied to the nozzles.
  • the present invention improves the performance of the earlier device, providing a more uniform discharge of smaller bubbles and also causes high local turbulence around the discharge openings.
  • a distributor body of generally rectangular shape having an elongated air chamber over which is resilient cover strip as in the earlier structure shown in said patent, but in addition thereto there is a resonance cavity or pulse chamber so arranged as to cause the air stream passing over it to resonate with the strip and create a higher amplitude and/or rate of vibration of the spring.
  • FIG. 1 is a schematic view showing in vertical transverse section a sewage treating tank with a pair of diffusers embodying the present invention therein;
  • FIG. 2 is a longitudinal section view through the diffuser of this invention
  • FIG. 3 is a transverse section through the diffuser looking along the line III-III of FIG. 2;
  • FIG. 4 is an inverted perspective view of the diffuser
  • FIG. 5 is a perspective view of the resilient strip forming part of the invention showing the taper thereof.
  • 10 designates a tank, usually several feet in depth, such as the aeration tank for treating sewage. It is in this tank that one or more of the diffusers, designated generally as 12, is located relatively close to the bottom so as to be several feet below the liquid level of the sewage and the solids which are distributed therethrough.
  • the diffusers 12 are used to discharge air into the tank to rise through the liquid and escape at the surface. The air serves to transfer oxygen to the liquid, i.e. aerate the liquid, and to agitate the tank contents. The oxygen is necessary for the chemical and biological processes utilized for treating the sewage.
  • Each diffuser 12 includes an elongated body 14 of generally rectangular shape, preferably of plastic, corrosion-resistant aluminum, or other material resistant to the contents of the tank, and of generally inverted U- shape in transverse section, with a top wall 16 that has a connector 17 into which an air supply pipe 18 is connected. It has spaced parallel side walls 20 and end wall portions 22. The side walls are shouldered throughout their lengths providing on the inner edges an inverted ledge 24. The end walls 22 terminate flush with the 7 level of these shoulders.
  • This structure provides an elongated chamber 26 with the face 28 of the body opening downward.
  • each end wall portion 22 of the body there is a cavity 30 which is elongated transversely of the body to substantially the full width of the chamber 26, but the width of which is quite small compared to the overall length of the chamber, and each cavity is separated from the main chamber 26 by a relatively narrow transverse partition, as shown.
  • Each end portion is preferably of a height greater than the remainder of the body 12, so that the cavities 30 are deeper than the chamber 26.
  • a thin flat strip 34 formed from a resilient material, such as stainless steel, providing a closure over the open face 28 of the chamber 26.
  • This strip 34 rests on ledges 24 between the vertical shoulders at the bottom edges of the side walls and its ends bear against and seat against the edges of the end walls 22 of the body.
  • the strip 34 is tapered from a central portion 34a thereof to the ends thereof. The degree of taper is selected in accordance with the maximum thickness of the strip 34 and the strength characteristics of the material used for the strip.
  • the strip 34 is clamped in place at the longitudinal center of the diffuser by a strip retainer 36, this retainer having a thick intermediate section 36a to fit between the shoulders of side walls 20 and bear against the strip 34 at the central portion 34a thereof.
  • Retainer 36 also has ears 36b at each end which overlap the bottom faces of the side walls of the diffuser. Machine screws or bolts 38 pass through the ears 36b and are screwed into the side walls of the diffuser body and hold the retainer 36 in position to clamp the strip 34 flat against the ledges or seat areas 24 and end walls 22.
  • the flexing action of the strip may be roughly compared to that of a reed in an organ or wind instrument, with the escaping air flowing across the lip of each cavity, or analogous to the blowing of air from ones lips across the top of a bottle, the cavities providing much the same kind of a resonant function.
  • This we feel, increases the amplitude, rate and/or energy level of vibration of strip 34 which causes the strip to shear the air to produce smaller size bubbles, and also causes an increase in the local turbulence at the discharge ends of the diffuser.
  • the result is an increase in oxygen transfer in the tank.
  • the decrease in thickness of the strip 34 from its mid portion 34a toward its free ends desirably supplements the effectiveness of this result.
  • Maximum vibration of the strip 34 may be obtained by sizing the taper thereof to conform with the size of cavities 30 whereby the strip will vibrate at the resonate frequency of the air cavities. It should be noted, however, that improved oxygen transfer has been found to result by using a flat strip in conjunction with the air cavities.
  • a stainless steel strip 34 having a thickness of about 0.032 inch at the central portion 34a and tapering to 0.0305 inch at the ends will be quite satisfactory and withstand the hydrostatic pressure in the liquid in which it is immersed.
  • cavities of a depth ranging between about one-fourth to one-half the length of the free-flexing portion of the strip 34 are satisfactory, but this is not critical.
  • cavities may have other shapes and more than one cavity may be provided at each end of the body.
  • one or more cavities may even be provided in the top of the air chamber so long as they provide resonance as the flow of air passes over them.
  • the cavity may be vented to the surrounding environment, assuming that the vent is so restricted to retain in the cavity, during operation, a pocket of air that will pulse with the vibration of the strip 34. The exact effect these cavities have on the action of the strip is not understood and for this reason we say that either or any combination of the amplitude, or energy level, or rate of vibration of the strip is increased.
  • a flat strip 34 may be used in the described diffuser; a tapered strip 34 may be used without any cavities 30 in the diffuser; or the strip 34 formed from a resilient nonmetallic material. Even other changes and modifications may be made in this invention within the contemplation of the following claims.
  • a diffuser comprising a body having a chamber therein with means for supplying gas under pressure thereto, one face of said chamber comprising a resilient closure member fixed at one point to the body and having edge portions seated on the body, said closure member being arranged to vibrate in a direction normal to its surface under pressure of gas in the chamber to release gas from the chamber, the body having a cavity therein which is in communication with the chamber when the closure is vibrating and said cavity located such that gas passing through the chamber passes over the cavity causing the gas in the cavity to resonate with the strip.
  • a diffuser as defined in claim 1 in which said cavity is positioned in the edge of the body under the edge portion against which the closure seats.
  • a gas diffuser including an elongated body having side and end walls and an open face defining a chamber therein, an elongated resilient strip covering the chamber, and a retainer extending across the strip for securing the strip to the body to allow the ends of the strip to flex away from the body under the urging of the pressure of gas in the chamber, the improvement therewith comprising:
  • said body having at least one resonance cavity therein located such that gas passing through the chamber passes over the cavity causing gas in the cavity to resonate with the strip.
  • said body has a pair of resonance cavities, each of which extends transversely of the body from the chamber to adjacent the closed face, and each of the cavities is adjacent an end wall of the body.
  • a gas diffuser including an elongated body having side and end walls and an open face defining a chamber therein, an elongated resilient strip covering the chamber, and a retainer extending across the strip for securing the strip to the body to allow the ends of the the strip to flex away from the body under the urging of the pressure of gas in the chamber, the improvement therewith comprising:
  • said body having at least one resonance cavity therein located such that gas passing through the chamber passes over the cavity causing gas in the cavity to resonate with the strip;
  • said strip being tapered from an intermediate portion thereof to at least one of the ends thereof.
  • each of the cavities is adjacent an end wall of the body; and said strip is tapered from an intermediate portion thereof to both ends thereof.
  • a gas diffuser for admitting gas to a fluid comprising:
  • a chamber in aid body extending from and including the open face of the body
  • a resilient strip secured at one point of its length to said body covering the open face of the body, the portion of the strip beyond the point of connection being free to flex outwardly under the urging of the pressure of gas in said chamber;
  • said body having at least one resonance cavity therein located such that gas passing through said chamber passes over the cavity causing gas in the cavity to resonate with the strip;
  • gas inlet connection means on said body for admitting gas into said chamber.

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  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Biodiversity & Conservation Biology (AREA)
  • Microbiology (AREA)
  • Hydrology & Water Resources (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Organic Chemistry (AREA)
  • Aeration Devices For Treatment Of Activated Polluted Sludge (AREA)
US3722836D 1970-06-24 1970-06-24 Gas diffuser Expired - Lifetime US3722836A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US4936970A 1970-06-24 1970-06-24

Publications (1)

Publication Number Publication Date
US3722836A true US3722836A (en) 1973-03-27

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Family Applications (1)

Application Number Title Priority Date Filing Date
US3722836D Expired - Lifetime US3722836A (en) 1970-06-24 1970-06-24 Gas diffuser

Country Status (3)

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US (1) US3722836A (enExample)
FR (1) FR2078319A5 (enExample)
GB (1) GB1281630A (enExample)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4215083A (en) * 1977-04-27 1980-07-29 Richter Gedeon Vegyeszeti Gyar Rt. Packing of equipment for the purpose of contacting mainly gaseous and liquid mediums
US4279742A (en) * 1976-12-20 1981-07-21 Institute Po Physikochimia Method of and apparatus for the flotation of mineral raw materials
US4337151A (en) * 1980-12-29 1982-06-29 Red Fox Industries Inc. Method and apparatus for pulsed timed control for sludge return line
US4495114A (en) * 1984-01-17 1985-01-22 Strauss Walter C Leaf spring diffuser with amplitude limit
US4815653A (en) * 1987-02-19 1989-03-28 Serve-All, Inc. Automatic removal of storage bin build-up
US5129553A (en) * 1990-06-05 1992-07-14 The Heil Company Aeration device
US20020163854A1 (en) * 2001-05-07 2002-11-07 Parks Richard E. Method and apparatus for gas induced mixing and blending of fluids and other materials

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2443396B (en) 2006-10-30 2011-10-19 Univ Sheffield Bubble generation for aeration and other purposes
US10377651B2 (en) 2006-10-30 2019-08-13 Perlemax Ltd Bubble generation for aeration and other purposes
EP2906679A1 (en) 2012-10-15 2015-08-19 Perlemax Ltd Bubble generation to strip components of a liquid

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4279742A (en) * 1976-12-20 1981-07-21 Institute Po Physikochimia Method of and apparatus for the flotation of mineral raw materials
US4215083A (en) * 1977-04-27 1980-07-29 Richter Gedeon Vegyeszeti Gyar Rt. Packing of equipment for the purpose of contacting mainly gaseous and liquid mediums
US4337151A (en) * 1980-12-29 1982-06-29 Red Fox Industries Inc. Method and apparatus for pulsed timed control for sludge return line
US4495114A (en) * 1984-01-17 1985-01-22 Strauss Walter C Leaf spring diffuser with amplitude limit
US4815653A (en) * 1987-02-19 1989-03-28 Serve-All, Inc. Automatic removal of storage bin build-up
US5129553A (en) * 1990-06-05 1992-07-14 The Heil Company Aeration device
US20020163854A1 (en) * 2001-05-07 2002-11-07 Parks Richard E. Method and apparatus for gas induced mixing and blending of fluids and other materials
US6629773B2 (en) * 2001-05-07 2003-10-07 Richard E. Parks Method and apparatus for gas induced mixing and blending of fluids and other materials

Also Published As

Publication number Publication date
GB1281630A (en) 1972-07-12
FR2078319A5 (enExample) 1971-11-05

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Date Code Title Description
AS Assignment

Owner name: TETRA RESOURCES, INC., A CORP OF DELAWARE,TEXAS

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:DRAVO CORPORATION, A CORP OF PA.;REEL/FRAME:004520/0581

Effective date: 19860212

Owner name: TETRA RESOURCES, INC., 25231 GROGANS MILL ROAD, TH

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:DRAVO CORPORATION, A CORP OF PA.;REEL/FRAME:004520/0581

Effective date: 19860212

AS Assignment

Owner name: TETRA RESOURCES, INC., A CORP OF DE,TEXAS

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:DRAVO CORPORATION, A PA CORP;REEL/FRAME:004659/0833

Effective date: 19861119

Owner name: TETRA RESOURCES, INC., 25231 GROGANS MILL ROAD, TH

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:DRAVO CORPORATION, A PA CORP;REEL/FRAME:004659/0833

Effective date: 19861119