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
  • C02F3/205—Moving, e.g. rotary, diffusers; Stationary diffusers with moving, e.g. rotary, distributors
  • C02F3/206—Moving, e.g. rotary, diffusers; Stationary diffusers with moving, e.g. rotary, distributors with helical screw impellers
• • 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
  • B01F23/233—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using driven stirrers with completely immersed stirring elements
  • B01F23/2331—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using driven stirrers with completely immersed stirring elements characterised by the introduction of the gas along the axis of the stirrer or along the stirrer elements
• • 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
  • B01F23/233—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using driven stirrers with completely immersed stirring elements
  • B01F23/2331—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using driven stirrers with completely immersed stirring elements characterised by the introduction of the gas along the axis of the stirrer or along the stirrer elements
  • B01F23/23311—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using driven stirrers with completely immersed stirring elements characterised by the introduction of the gas along the axis of the stirrer or along the stirrer elements through a hollow stirrer 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
  • B01F23/233—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using driven stirrers with completely immersed stirring elements
  • B01F23/2333—Single stirrer-drive aerating units, e.g. with the stirrer-head pivoting around an horizontal 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
  • B01F23/233—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using driven stirrers with completely immersed stirring elements
  • B01F23/2334—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using driven stirrers with completely immersed stirring elements provided with stationary guiding means surrounding at least partially the stirrer
• • 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
  • B01F23/233—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using driven stirrers with completely immersed stirring elements
  • B01F23/2335—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using driven stirrers with completely immersed stirring elements characterised by the direction of introduction of the gas relative to the stirrer
  • B01F23/23354—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using driven stirrers with completely immersed stirring elements characterised by the direction of introduction of the gas relative to the stirrer the gas being driven away from the rotating stirrer
• • 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
  • B01F23/233—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using driven stirrers with completely immersed stirring elements
  • B01F23/2336—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using driven stirrers with completely immersed stirring elements characterised by the location of the place of introduction of the gas relative to the stirrer
  • B01F23/23366—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using driven stirrers with completely immersed stirring elements characterised by the location of the place of introduction of the gas relative to the stirrer the gas being introduced in front of the stirrer
• • 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
  • C02F3/205—Moving, e.g. rotary, diffusers; Stationary diffusers with moving, e.g. rotary, distributors
  • C02F3/207—Moving, e.g. rotary, diffusers; Stationary diffusers with moving, e.g. rotary, distributors with axial thrust propellers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F27/00—Mixers with rotary stirring devices in fixed receptacles; Kneaders
  • B01F27/05—Stirrers
  • B01F27/07—Stirrers characterised by their mounting on the shaft
  • B01F27/072—Stirrers characterised by their mounting on the shaft characterised by the disposition of the stirrers with respect to the rotating axis
  • B01F27/0725—Stirrers characterised by their mounting on the shaft characterised by the disposition of the stirrers with respect to the rotating axis on the free end of the rotating axis
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F27/00—Mixers with rotary stirring devices in fixed receptacles; Kneaders
  • B01F27/05—Stirrers
  • B01F27/11—Stirrers characterised by the configuration of the stirrers
  • B01F27/113—Propeller-shaped stirrers for producing an axial flow, e.g. shaped like a ship or aircraft propeller
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F27/00—Mixers with rotary stirring devices in fixed receptacles; Kneaders
  • B01F27/05—Stirrers
  • B01F27/11—Stirrers characterised by the configuration of the stirrers
  • B01F27/19—Stirrers with two or more mixing elements mounted in sequence on the same axis
  • B01F27/192—Stirrers with two or more mixing elements mounted in sequence on the same axis with dissimilar elements
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F27/00—Mixers with rotary stirring devices in fixed receptacles; Kneaders
  • B01F27/60—Mixers with rotary stirring devices in fixed receptacles; Kneaders with stirrers rotating about a horizontal or inclined axis
  • B01F27/61—Mixers with rotary stirring devices in fixed receptacles; Kneaders with stirrers rotating about a horizontal or inclined axis about an inclined axis
• • 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

• the present invention relates broadly to a pro ⁇ peller mechanism and apparatus for mixing a gas with a liquid. More particularly, the present invention relates to a propeller mechanism and apparatus for aerating water in a water treatment process.
• the present invention can be used in municipal and private water treatment facilities.
• Aeration apparatus are utilized in the treatment of water for the purpose of increasing the dissolved oxygen (DO) content of the water.
• DO dissolved oxygen
• a certain amount of dissolved oxygen is required for the life of fish and other aquatic organisms.
• Dissolved oxygen is also required to prevent the formation of offensive odors and to break down organic matter in water.
• the biochemical oxygen demand (BOD) is the measure of the amount of oxygen consumed in the biolo ⁇ gical processes which break down organic matter in water.
• a high BOD indicates that large amounts of organic waste are present and will use up large amounts of dissolved oxygen.
• Aeration apparatus are especially useful in in ⁇ creasing the amount of dissolved oxygen and, hence, are useful in high-BOD situations.
• Aerators utilized in waste water treatment can be broadly classified into two types: a diffused air type, and a mechanical type.
• a diffused air type aerator intro ⁇ Jerusalem air or pure oxygen into water via submerged porous diffusers or nozzles.
• Mechanical type aerators agitate the water so as to promote solution of air from the atmosphere.
• Mechanical type aerators are further classified as either surface aerators or turbine aerators.
• a surface aerator utilizes a submerged or partially submerged impel ⁇ ler which agitates the water vigorously to thereby entrain air in the water and cause a rapid change in the air-water interface.
• Turbine aerators generally utilize a rotating impeller which is disposed a certain distance below the surface of the water being treated.
• a draft tube is sup ⁇ ported generally coaxial with the axis of rotation of the impeller and is utilized to supply air to the liquid adja-_ cent the impeller.
• U.S. Patent No. 3,465,706 to Gwidt an app atus for injecting air into the underwater exhaust outboard motors is disclosed.
• Air is injected into wa through a hollow propeller tube upon which a marine-t propeller is attached.
• a diff ser assembly comprised o air of U-shaped and crossed plates is attached at outlet end of the propeller tube. The air outlet end disposed relatively close to the marine prop and the dif ser plates have a relatively narrow width.
• a round disc attached to this lower end of the plates. The round d would apparently inhibit axial flow of water and air b bles.
• the propeller mechanism is compri of a support tube and a plurality of propeller bla attached thereto.
• the support tube is adapted to be tached to an end of a rotatable tube of an aeration app atus.
• the propeller blades are attached to the ou surface of the support tube.
• Each propeller blade ha leading ' end, a tail end, an outer edge and an impell surface. The outer edge at the leading end extends o wardly from the outer surface of the support tube at angle less than 90°.
• the impelling surface is adapted move into a liquid in which the support tube is rotat That is, the impelling surface faces in the direction rotation.
• the impelling surface has a varying rake t changes to a more positive rake from the leading end to tail end.
• the support tube preferably has a diffus section which extends below the lowermost extent of propeller blades a sufficient distance such that air b bles which are injected from an open air outlet end of support tube do not intermix with the water through wh the propeller blades are rotated when the support tube held at an acute angle relative to the horizontal.
• a plurality of plate members are attached to the support tube adjacent its air outlet end and extend a distance below the air outlet end for breaking up air bubbles exiting the air outlet end and for causing a radial flow thereof.
• the plate members are preferably comprised of a plurality of plates extending in a plurality of planes.
• At least one of the plates has a lowermost section which is bent backward in the direction of rotation of the propeller member so as to permit or reestablish an axial flow of the gas bubbles and water at the lowermost end of the plate members.
• the axial flow is reestablished after the portion of the plate members above this lowermost section have established a radial flow.
• the present invention is also directed to an improvement of the apparatus as disclosed in United States Patent Application Serial Number 898,983 of Daniel J. Durda on an "Apparatus for Mixing a Gas and a Liquid", which is assigned to the same assignee as the present invention.
• the apparatus is comprised of a hollow outer housing and a hollow inner tube received within the outer housing.
• the inner tube is mounted for rotary motion within the hollow interior of the outer housing.
• a motor is attached to the outer housing adjacent a first end thereof and is drivingly coupled to a first end of the inner tube.
• the inner tube includes a support tube which extends beyond the second end of the outer housing.
• An inlet is formed in the inner tube for admitting a gas to the hollow interior of the inner tube.
• a plurality of propeller blades are attached to the support tube to form a propeller mechanism.
• the propeller mechanism is adapted to be placed in a liquid and to propel the liquid in which the propeller mechanism rotates.
• the propeller blades have a maximum transverse dimension in a plane passing through the propeller blades and generally perpendicular through the axis of the support tube.
• Each propeller blade has a leading end, a tail end, and outer edge and an impelling surface facing in the direction in which the inner tube is rotated. The outer edge at the leading end extends outwardly from the outer surface of
• OMPI ⁇ . 1P0 support tube at an angle less than 90°.
• the impellin surface has a varying rake which changes to a more positiv rake from the leading end to the tail end.
• the suppor tube has a diffusion section which extends below the lower most extent of the propeller blades and an open air outle end which forms the second end of the inner tube. Th diffusion section extends a predetermined distance belo the propeller blades such that the propeller blades ca rotate through a liquid substantially free of gas bubble injected into the liquid through the air outlet end whe the axis of the inner tube is disposed at an acute angl relative to the horizontal.
• the propeller mechanism also preferably include a plurality of plate members comprised of a plurality o plates for causing the breaking up of air bubbles exitin the air outlet end and for causing a radial flow thereof
• the plate members also cause a low pressure area in th area of the water in which they rotate. Such a low pres sure area also increases the injection rate of the air int the water.
• a lower section of at least one of the plate is bent backward from the direction of rotation of th inner tube so as to permit or reestablish an axial flow o gas bubbles and water.
• FIGURE 1 is a side elevational view illustratin an apparatus in accordance with the present inventio disposed within a liquid.
• FIGURE 2 is a partial side elevational and par tial sectional view of the apparatus.
• FIGURE 3 is a sectional view of the lower end of the apparatus on an enlarged scale.
• FIGURE 4 is a view illustrating a U-joint at ⁇ tached to an end of the inner tube on an enlarged scale.
• FIGURE 5 is an end elevational view of a motor adapter.
• FIGURE 6 is a view taken along lines 6-6 of FIGURE 5.
• FIGURE 7 is a perspective view illustrating the motor adaptor connected to the outer tube.
• FIGURE 8 is a perspective view illustrating the lower end of the apparatus.
• FIGURE 9 is a plan view of the lower end of the apparatus-.
• FIGURE 10 is a fragmentary cross-sectional view of the inner and outer tubes of the apparatus.
• FIGURE 11 is a cross-sectional view taken along lines 11-11 of FIGURE 4.
• FIGURE 12 is a cross-sectional view taken along lines 12-12 of FIGURE 1.
• FIGURE 13 is a perspective view illustrating a prop mechanism in accordance with the present invention attached to an aeration apparatus.
• FIGURE 14 is a top plan view of the propeller mechanism itself.
• FIGURE 15 is a bottom plan view of the propeller mechanism itself.
• FIGURE 16 is a side elevational view on an en ⁇ larged scale, with portions broken away, of the propeller mechanism.
• FIGURES 17, 18 and 19 are sectional views taken generally respectively along lines 17-17,-18-18, and 19-19 of FIGURE 16 illustrating the varying rake of the propeller blades.
• FIGURE 20 is a side elevational view of another embodiment of the propeller mechanism in accordance with the present invention.
• FIGURE 21 is a side elevational view illustrati a typical marine prop of the prior art.
• FIGURE 1 an apparatus in accordance with the present inventi designated generally as 10.
• the apparatus 10 as shown FIGURE 1 is disposed within a liquid 12.
• the liquid 12 generally waste water or sewage to which oxygen must injected.
• a gas, generally ambient air, is shown enteri the liquid 12 as a plurality of bubbles 14.
• the apparat 10 is designed to be portable and is shown supported on platform 15 by means of a suitable fastener " 16 which attached to an arm 18 extending from the apparatus 10.
• T apparatus 10 is shown supported in the liquid 12 at angle 20 relative to the horizontal. The angle 20 between the horizontal and the vertical.
• the apparatus 10 includes an outer tube means housing 22 and an inner tube means 24.
• the outer housi 22 is comprised of a central tube 26, a motor adaptor attached to a first or upper end of the central tube 2 and a bearing housing 30 attached to a second or lower e of the central tube 26.
• the inner tube means 24 includes longitudinally extending tube 32, a propeller tube 34, a a diffusion tube 36.
• the propeller tube 34 has a first end 38 who outer diameter is less than the inner diameter of an end of the tube 32. The end 38 thus can be received within t tube 32 and secured thereto by suitable means such welding.
• the propeller tube 34 has a second end 42. best seen in FIGURE 3, the second end 42 has an out diameter which is less than the outer diameter of a medi section 44 of the propeller tube 34.
• a shoulder 46 is th formed at the juncture between the second end 42 and t medial section 44.
• a propeller 48 can thus be receiv about the second end 42 and abut against the shoulder 4
• the lowermost portion of the second end 42 has a threaded exterior.
• the interior of one end of the diffusion tube 36 is threaded to mate with the threads of the diffusion tube 36.
• the propeller 48 can thereby be held on the propeller tube 34 by threading the diffusion tube 36 onto the propel ⁇ ler tube 34 so that the propeller 48 is frictionally en ⁇ gaged between the shoulder 46 and the diffusion
• the motor adaptor 28 includes a cylindrical section 50 and a truncated cone section 52.
• the truncated cone section 52 is divided into a first section 54 and a second section 56.
• a plurality of ribs 58 are formed in the second section 56.
• a plurality of support arms 60 extend radially outward from the ribs 58.
• a handle 62 also ex ⁇ tends outwardly from the motor adaptor 28. The handle 62 is used as a grip to either carry or adjust the position of the apparatus 10.
• a motor 61 is secured to the innermost holes 64 in the arms 60.
• a casing or housing 66 is attached to the outer holes 68 in the arm 60.
• the housing 66 includes a circumferential wall 70 which completely encircles the motor 61 and a top wall 72.
• the top wall 72 has a plurality of holes or slots 74.
• the slots or holes 74 provide an air inlet for air to be drawn into the interior of the housing 66.
• the housing 66 forms a plenum 78 around the motor 61.
• the motor 61 has a fan section 80 which includes a fan for drawing air across the outer surface of the motor 61 in order to keep the motor 61 cool. The movement of the air into and through the plenum 78 is illustrated by arrows 76.
• Air as it passes through the plenum 78 is heated by the motor 61.
• the air passes through the plenum 78 to the hollow interior of the motor adaptor 28.
• the motor adaptor 28 also forms an enclosed plenum so that the air is confined to move down the hollow interior of the outer tube means 22.
• Inlet means such as air inlet slots 82, are formed in the tube 32 adjacent its first or upper end.
• the heated air which is moving down the hollow interior of the outer tube means 22 passes into the hollow interior of the inner tube means 24 via the air inlet slots 82.
• Only one air "inlet slot 82 is shown FIGURES 2 and 4, however, preferably at least two air i slots 82 are formed in the tube 32. As will be expla more fully hereinafter, the heated air thereafter pa downwardly through the tube 32 and out the open end of diffusion tube 36.
• the inner tube means 24 is supported within outer tube means 22 at one of its ends by a flexible c ling, such as a U-joint 86.
• the other end of the i tube means 24 is supported in a water bearing 88 whic secured within the bearing housing 30.
• the U-joint couples one end of the tube 32 to a rotary-driven d shaft 90 of the motor 61, while the water bearing 88 mits the rotation of the entire inner tube means 24.
• axis of the inner tube means 24 is shown as arrow 92.
• the U-joint 86 includes an upper yoke 94 coup to a lower yoke 96 by means of a crosshead 98.
• the up yoke 94 has a head section 100 with a central bore extending therein.
• the drive shaft 90 of the motor 61 secured within the bore 102 to transmit the rotary mo of the drive shaft 90 to the U-joint 86.
• the upper yoke also includes a pair of opposing arms 104, 106.
• the 104 has a hole 109 extending through it and the arm 106 a hole 111 extending through it.
• the crosshead 98 include a first fin 108 with opposite ends 113, 115.
• the lower yoke 96 a head section 110 with a bore 112 extending therein. upper end of the tube 32 is secured within the bore 112 that the rotation of the yoke 86 is transmitted to the t 32.
• the yoke 96 also includes a pair of opposing arms 1 116.
• the arm 114 has a hole 118 extending through it the arm 116 has a hole 120 extending through it.
• crosshead 98 includes a second pin 126 with opposite e 122, 124.
• the end 122 is pivotably supported in the h 118 and the end 124 is pivotably supported in the hole 1 Clips 128 hold the ends 113, 115, 122, 124 in the respe ive holes 109, 111, 118, 120.
• the lower yoke 96 and upper end of the tube 32 attached thereto are thus capable of pivoting about transverse axes 130, 132 of the pins 108, 126.
• the U-joint 86 permits universal motion of the first or upper end of the tube 32 while transmitting rotary motion from the drive shaft 90 to the tube 32.
• the water bearing 88 includes a plurality of bearing bars 134 extending along its length.
• the bearing bars 134 are so disposed that a gap 136 exists between adjacent bars 134.
• a liquid such as water
• the water is permitted to flow in the gaps 136- and also between the outer circumference of the propeller tube 34 and the bars 134. Water thus acts as a lubricant between the propeller tube 34 and the bearing 88.
• the tube 32 is mechanically straightened to exact tolerances.
• the tube 32 is straightened so that the cylin ⁇ drical wall 138 of the tube 32 is aligned about the axis 92 a certain distance 140 to a tolerance of better than fif ⁇ teen thousandths of an inch. That is, the distance 140 is the same throughout the entire length of the tube 32 to a tolerance better than fifteen thousandths of an inch. Applicant has discovered that when the tube 32 is straigh ⁇ tened to a tolerance of only fifteen thousandths of an inch, vibration and whipping of the tube 32 occurs such that early breakage of the tube 32 results.
• a plurality of fins 142 extend radially outw from the bearing housing 30. Each fin 142 has a distal 144.
• a vortex shield 146 is attached to a number of distal ends 144.
• the shield 146 has a lengthwise dimens extending generally parallel to the axis 92 and a circ ferential dimension extending in an arc less than 360°. best seen in FIGURE 8, the shield 146 has a lower end in a generally truncated-V configuration. A portion of lower end 148 extends above the propeller 48. The shi prevents the formation of a vortex adjacent the propel in the liquid in which the propeller is driven.
• the apparatus 10 operates in the following m ner.
• the apparatus 10 is disposed in a liquid 12 at angle 20 relative to the horizontal.
• the liquid 12 generally sewage or waste water which contains orga materi _al and which requires a high level of dissol oxygen.
• the motor 61 is driven preferably by an electri source (not shown).
• the drive shaft 90 of the motor 61 thereby rotated and the rotary motion is transferred to inner tube means 24.
• the propeller 48 rotates in liquid 12 and propels the liquid 12 by the open end of diffusion tube 36 creates a venturi or suction effect whi draws air down through the hollow interior of the in tube means 24.
• the air which is drawn through the holl interior of the inner tube means 24 was preheated whi passing through the plenum 78.
• the preheating of the air desirable when the apparatus 10 is used as an aerator bodies of water in northern climes wherein the body water generally freezes over in the winter.
• the preheated air By utilizi the preheated air, at least a portion of the body of wa can be kept unfrozen or open. The unfrozen portion of water thus provides a contact surface with the ambient a wherein the air can dissolve into the water. If the bo of water is completely frozen over, such an open air-wa contact at the surface of the water is lost.
• the diffusion tube 36 has a length which is at least fifty percent of the transverse dimension of the propeller 48.
• the transverse dimension of the propeller 48 is indicated as line 150 which lies in a plane passing through the propeller and perpendicular to the axis 92.
• the open end of the diffusion tube 36 has a curved inner circumferential surface 39. See FIGURE 3.
• the air bubbles 14 disperse over a larger area when the inner circumferen- tial surface of the open end of the diffusion tube 36 is curved than when the inner circumferential area is straight.
• the curved surface 39 of the diffusion tube 36 increases the dispersion of air bubbles when the marine propeller 48 is used, such a curved surface does not aid the operation of the aeration appara ⁇ tus when the propeller mechanism illustrated in FIGURES 13-20 is used.
• the shield 146 prevents the formation of a vortex of liquid at the propeller 48 and, hence, also increases the efficiency of the apparatus.
• the apparatus 10 is disposed at an angle 20 within the liquid 12 the liquid 12 moved by the propeller 48 also aids in dispersing the air bubbles 14 over a large area in the liquid 12
• FIGURES 13-19 There is shown in FIGURES 13-19 a propell mechanism 210 in accordance with the present inventio
• the propeller mechanism 210 is shown in FIGURE 13 attach to a portion of an aeration apparatus 212. Only a porti of the apparatus 212 is shown in FIGURE 13.
• the structu of the apparatus 212 is the same as the apparatus disclos in FIGURES 1-12 except for the propeller mechanism.
• the propeller mechanism 210 includes a suppo tube 214 and a plurality of propeller blades 216 attach to the outer surface of the tube 214.
• the support tube 2 has an inlet end 218 which is attached in any suitab manner to an end of an inner tube 220 of the aerati apparatus 212.
• the support tube 214 has a diffusion se tion 222 which extends below the lowermost extent of t propeller blades 216.
• the support tube 214 also has open air outlet end 224 through which gas or air can injected into the liquid in which the propeller mechani 210 is disposed.
• the diff sion section 222 extends a sufficient distance below t propeller blades 216 such that air ejected from the a outlet end 224 does not intermix with the liquid throu which the propeller blades 216 are rotated when the axis the inner tube 220 is disposed at an acute angle relati to the horizontal, for example at approximately 25°.
• Each propeller blade 216 has a lead end 226, tail end 228, an outer edge 230 and an impelling surfa 232.
• the outer edge 230 extends outward from the out surface of the support tube 214 at the lead end 226 at angle less than 90°, and preferably less than 45°.
• Each propeller blade 216 is preferably made of flat piece of rigid material and one flat major surface the material forms the impelling surface 232.
• the impe ling surface 232 faces in the direction in which the pro ⁇ peller mechanism 210 is designed to rotate.
• the impelling surface 232 has a slightly nega ⁇ tive rake adjacent the lead end 226. That is, the impel- ling surface 232 is bent slightly back or away from a radius 233 extending from the rotational axis.
• FIGURE 18 which is a sectional view taken farther along the length of the propeller blade 216, the rake of the impelling surface 232 has changed to a slightly positive rake.
• the impelling surface 232 is leaning in towards a radius 235 extending from the rotational axis.
• the rake of the impelling surface 232 is even more positive, i.e. the impelling surface 232 is slanted in towards a radius 237 at an even greater angle.
• FIGURES 17-19 illustrate the rake going from a nega ⁇ tive rake to a positive rake, it should be understood that the rake of the propeller blades 216 need not start at a negative rake, but merely that the rake increase to a more positive rake from the lead end 226 to the tail end 228.
• a plurality of plates " 238, 240, 242 are attac to the support tube 214 at its air outlet end 224.
• plate 238 is preferably a flat plate which passes genera through a first plane.
• e plate 238-242 is fitted within a slot 244 formed in support tube 214.
• the area at which plates 238-242 cross is disposed within the hollow inter of the support tube 214.
• the portions of the plates 2 242 which are disposed within the hollow interior of support tube 214 are thus in an area where only air present when the aerator is operating. Thus, the foul of the plates 238-242 at their crossed intersection prevented. If the area where the plates 238-242 cros were located at the air-water interface, solid materi would tend to gather at the intersection of the pla 238-242.
• plates 238-242 In order to prevent fouling of the propel mechanism 210 at the point where the plates 238-242 int sect with the outer surface of the support tube 214, plates 238-242 have tapered ends 255 that extend from support tube 214 with a gradually increasing transve dimension.
• the propeller bla 216 have a maximum transverse dimension indicated by a l 246.
• the first plate 238, as seen in FIGURE 15, ha maximum transverse dimension approximately the same as maximum transverse dimension of the propeller blades 2
• the maximum transverse dimension the plate 238 extends over a large portion of the longi dinal or axial dimension of the plate 238.
• maximum transverse dimension of the combined second third plates 240, 242 is also approximate to the maxi transverse dimension of the propeller blades 216.
• the m function of the plates 238-242 is to increase the amount air injected into water by the aeration apparatus has been found that if the maximum transverse dimension of the plates 238-242 is too narrow, i.e.
• the amount of air injected does not increase appreci- ably.
• the amount of air injected into the water by apparatus 212 increases. It has been found that an optimum or satisfactory level of air injection to power consumption results when the transverse dimension of the plates 238-242 approximates the transverse dimension of the propeller blades 216.
• the entire plate 238 lies in a single plane and an upper portion 248 of the second and third plates 240, 242 lies in a single plane transverse to the plane of the first plate 238. However, a lower portion 250 of each plate 240, 242 is bent backward or away from the direction of rotation of the propeller mechanism 210.
• the plates 238-242 function to increase the amount of air injected into the water.
• the propeller mechanism 210 in addition to increasing the amount of air which is injected into the water, also increases the percentage of oxygen which dissolves in the water. Applicants believe that the increase in the amount of dissolved oxygen is caused by the action of the plates 238-242.
• the plates 238-242 cause the air bubbles which exit the air outlet end 224 to be broken up into fine bubbles and cause the bubbles to flow radially outward. Applicants believe that breaking the bubbles down into smaller air bubbles decreases the reliance upon "hang time" to cause the dissolving of oxygen into the water. Since the bubbles are broken into fine bubbles which have a smaller diameter, the interface area between air and water for a given volume of air is in ⁇ creased and thus dissolving of oxygen occurs more rapidly. The time element which is required for oxygen transfer is reduced. The shortening of this time element is especially useful where the aeration is required in a shallow area in which hang time would be minimal.
• the lower bent portions 250 of the blades 240-2 tend to reestablish an axial flow of the air bubbles water at the lowermost end of the propeller mechanism 21
• the reestablishment of the axial flow is desirable so t the mixing of the air bubbles and the inducement of a fl in the water can be optimized. If all of the plates 238-2 were completely flat, too great a radial flow would established.
• the prop mechanism 210 thus provides broad vers tility in designing a prop mechanism for various wat treatment conditions.
• the lower portions 250 can be made relatively small compared to the remaining portion of the plates 240, 24 The oxygen injection is thus increased, while the axi flow is decreased. Also, the amount of power which is p into air injection is increased over the amount of pow that is placed into mixing.
• whe mixing is more important than the amount of oxygen which to be injected, the length of the lower portion 250 can increased so that more axial flow for mixing is utilized.
• FIGURE 20 There is illustrat in FIGURE 20 an alternate embodiment of a propeller mech nism, designated generally as 210'.
• the propeller mech nism 210' is comprised of a support hub 214' and a plura ity of propeller blades 216' attached to the outer surfa thereof.
• the propeller blades 216' are constructed t same as the propeller blades 216.
• the propeller mechani 210' does not utilize any plates at its air outlet end 22 to cause a radial flow of gas bubbles and water.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Life Sciences & Earth Sciences (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)
• Mixers Of The Rotary Stirring Type (AREA)
• Nozzles (AREA)
• Farming Of Fish And Shellfish (AREA)

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Citations (13)

• 1979
  • 1979-04-10 WO PCT/US1979/000224 patent/WO1979000958A1/en unknown
  • 1979-04-10 GB GB7943399A patent/GB2035823B/en not_active Expired
  • 1979-04-10 JP JP50071279A patent/JPS55500281A/ja active Pending
  • 1979-04-11 CA CA325,301A patent/CA1110786A/en not_active Expired
  • 1979-04-20 JP JP54048092A patent/JPS5820294B2/ja not_active Expired

Patent Citations (13)

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