US3545731A - Apparatus for producing bubbles of very small,microscopic size - Google Patents

Apparatus for producing bubbles of very small,microscopic size Download PDF

Info

Publication number
US3545731A
US3545731A US3545731DA US3545731A US 3545731 A US3545731 A US 3545731A US 3545731D A US3545731D A US 3545731DA US 3545731 A US3545731 A US 3545731A
Authority
US
United States
Prior art keywords
flow
sparger
surface
fluid
gas
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
Inventor
Donald S Mcmanus
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.)
General Dynamics Corp
Original Assignee
General Dynamics 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.)
Filing date
Publication date
Application filed by General Dynamics Corp filed Critical General Dynamics Corp
Priority to US59287266A priority Critical
Application granted granted Critical
Publication of US3545731A publication Critical patent/US3545731A/en
Anticipated expiration legal-status Critical
Application status is Expired - Lifetime legal-status Critical

Links

Images

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01FMIXING, e.g. DISSOLVING, EMULSIFYING, DISPERSING
    • B01F5/00Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F5/04Injector mixers, i.e. one or more components being added to a flowing main component
    • B01F5/0403Mixing conduits or tubes, i.e. conduits or tubes through which the main component is flown
    • B01F5/0413Mixing conduits or tubes, i.e. conduits or tubes through which the main component is flown provided with a venturi element
    • B01F5/0425Mixing conduits or tubes, i.e. conduits or tubes through which the main component is flown provided with a venturi element characterized by the place of introduction of the main flow
    • B01F5/0426Mixing conduits or tubes, i.e. conduits or tubes through which the main component is flown provided with a venturi element characterized by the place of introduction of the main flow the main flow being injected in the circumferential area of the venturi, creating an aspiration in the central part of the conduit
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01FMIXING, e.g. DISSOLVING, EMULSIFYING, DISPERSING
    • B01F3/00Mixing, e.g. dispersing, emulsifying, according to the phases to be mixed
    • B01F3/04Mixing, e.g. dispersing, emulsifying, according to the phases to be mixed gases or vapours with liquids
    • B01F3/04099Introducing a gas or vapour into a liquid medium, e.g. producing aerated liquids
    • B01F3/0446Introducing a gas or vapour into a liquid medium, e.g. producing aerated liquids using flow mixing means for introducing the gas, e.g. in conduits or in vessels
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01FMIXING, e.g. DISSOLVING, EMULSIFYING, DISPERSING
    • B01F5/00Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F5/04Injector mixers, i.e. one or more components being added to a flowing main component
    • B01F5/0403Mixing conduits or tubes, i.e. conduits or tubes through which the main component is flown
    • B01F5/0413Mixing conduits or tubes, i.e. conduits or tubes through which the main component is flown provided with a venturi element
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01FMIXING, e.g. DISSOLVING, EMULSIFYING, DISPERSING
    • B01F5/00Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F5/04Injector mixers, i.e. one or more components being added to a flowing main component
    • B01F5/0403Mixing conduits or tubes, i.e. conduits or tubes through which the main component is flown
    • B01F5/045Mixing conduits or tubes, i.e. conduits or tubes through which the main component is flown the additional component being introduced in the centre of the conduit
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/72Treatment of water, waste water, or sewage by oxidation
    • C02F1/76Treatment of water, waste water, or sewage by oxidation with halogens or compounds of halogens
    • C02F1/763Devices for the addition of such compounds in gaseous form
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00Biological treatment of water, waste water, or sewage
    • C02F3/02Aerobic processes
    • C02F3/12Activated sludge processes
    • C02F3/20Activated sludge processes using diffusers
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01FMIXING, e.g. DISSOLVING, EMULSIFYING, DISPERSING
    • B01F3/00Mixing, e.g. dispersing, emulsifying, according to the phases to be mixed
    • B01F3/04Mixing, e.g. dispersing, emulsifying, according to the phases to be mixed gases or vapours with liquids
    • B01F3/04099Introducing a gas or vapour into a liquid medium, e.g. producing aerated liquids
    • B01F3/04106Introducing a gas or vapour into a liquid medium, e.g. producing aerated liquids the gas being introduced by bubbling, e.g. within receptacles or tanks
    • B01F3/04113Arrangement or manipulation of the gas bubbling devices
    • B01F3/04241Diffusers
    • B01F2003/04354Diffusers characterized by the nature of the diffuser gas outlet
    • B01F2003/0439Pores
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01FMIXING, e.g. DISSOLVING, EMULSIFYING, DISPERSING
    • B01F3/00Mixing, e.g. dispersing, emulsifying, according to the phases to be mixed
    • B01F3/04Mixing, e.g. dispersing, emulsifying, according to the phases to be mixed gases or vapours with liquids
    • B01F3/04099Introducing a gas or vapour into a liquid medium, e.g. producing aerated liquids
    • B01F2003/04843Introducing a gas or vapour into a liquid medium, e.g. producing aerated liquids characterized by the gas being introduced or the material in which the gas is introduced
    • B01F2003/04851Introducing a gas or vapour into a liquid medium, e.g. producing aerated liquids characterized by the gas being introduced or the material in which the gas is introduced characterized by the gas being introduced
    • B01F2003/04858Introducing a gas or vapour into a liquid medium, e.g. producing aerated liquids characterized by the gas being introduced or the material in which the gas is introduced characterized by the gas being introduced in the form of microbubbles, e.g. to obtain aphrons
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01FMIXING, e.g. DISSOLVING, EMULSIFYING, DISPERSING
    • B01F3/00Mixing, e.g. dispersing, emulsifying, according to the phases to be mixed
    • B01F3/04Mixing, e.g. dispersing, emulsifying, according to the phases to be mixed gases or vapours with liquids
    • B01F3/04099Introducing a gas or vapour into a liquid medium, e.g. producing aerated liquids
    • B01F2003/04843Introducing a gas or vapour into a liquid medium, e.g. producing aerated liquids characterized by the gas being introduced or the material in which the gas is introduced
    • B01F2003/04851Introducing a gas or vapour into a liquid medium, e.g. producing aerated liquids characterized by the gas being introduced or the material in which the gas is introduced characterized by the gas being introduced
    • B01F2003/04865Aerating, i.e. introducing oxygen containing gas in liquids
    • B01F2003/04872Normal air
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01FMIXING, e.g. DISSOLVING, EMULSIFYING, DISPERSING
    • B01F2215/00Auxiliary or complementary information in relation with mixing
    • B01F2215/04Technical information in relation with mixing
    • B01F2215/0413Numerical information
    • B01F2215/0418Geometrical information
    • B01F2215/0431Numerical size values, e.g. diameter of a hole or conduit, area, volume, length, width, or ratios thereof
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02WCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W10/00Technologies for wastewater treatment
    • Y02W10/10Biological treatment of water, waste water, or sewage
    • Y02W10/15Aerobic processes

Description

United States Patent [72] Inventor Donald S. McManus Groton Long Point, Connecticut [21 Appl. No. 592,872

[22] Filed Nov. 8, 1966 [45] Patented Dec. 8, 1970 [73] Assignee General Dynamics Corporation New York, New York 10022 I corporation of Delaware [54] APPARATUS FOR PRODUCING BUBBLES OF Primary Examiner-Ronald R. Weaver Attorney-William C. Everett ABSTRACT: An apparatus is provided for producing bubbles of 5 to 10 micron size in a liquid by a sparger inside a pipe wherein the clearance between the sparger and the pipe is maintained in relation to the velocity of the liquid passing over the sparger such that the height of the laminar sublayer in the liquid is maintained less than 10 microns. The bubbles are produced by pressure perturbations in the turbulent layer above the laminar sublayer such that as gas issues from the sparger through the laminar sublayer the pressure perturbations will snap oil the bubbles before they can grow larger than 10 microns in size. A narrow annular passageway is provided between the sparger and pipe. This annular passageway is provided with an increasing taper in the downstream direction of the liquid stream. The taper increase in flow cross section ,produces a corresponding pressure increase in the liquid str'e'am in the direction of flow which is sufficient to compensate for the pressure drop due to friction losses. The liquid flow pressure over the surface of the sparger is maintained uniform. A stream lined tail cone portion is attached to the downstream end of the sparger. A convergence in the inner wall of the shell member in juxtaposition with the tail cone portion forms an exit passage of reduced cross section for the liquid stream. A handwheel is attached to the sparger for axially displacing the sparger relative to the shell member for adjusting the clearance space between the tail cone portion and the exit passage.

VERY SMALL, MICROSCOPIC SIZE 7Claims,5DrawingI"1gs. [52] 11.8. 261/122, 210/220 [51] IntJ C021: 1/02, BOlf 3/04, B01f 5/04 [50] FleldofSeareh 261/121, 122,124;210/14,l5, 220

[56] References cm UNITED STATES PATENTS 1,803,054 4/1931 Broido ..26l/(Desuperheater) 2,695,710 11/1954 Gibbs.... 261/122X 3,256,802 6/1966 Karr 261/122X FOREIGN PATENTS 694,918 7/1953 Great Britain 261/122 a JB 4/ PATENTED at; 8 I970 sum 2 BF 2 APPARATUS FOR PRODUCING nunnuas or VERY SMALL, MICROSCOPIC SIZE This invention is directed to means for producing large, homogeneous quantities of gas bubbles of microscopic size on the orderof -l0 microns in diameter. The invention finds 1 and other processes wherein a gas-phase material is to be dissolved or dispersed into a liquid medium medium.

The present invention utilizes the distinctive boundary layer characteristics of turbulent fluid-flow phenomena in order to achieve the consistent production and dispersion of large, homogeneous quantities microscopically sized bubbles (hereinafter sometimes referred to as microbubbles). The means of the present invention difiers primarily from prior art techniques for the production of bubbles in that (l) dense clouds comprised exclusively of vary large numbers of bubbles of microscopic size, on the order of 5l0 microns in diameter, are consistently produced and are dispersed into the fluid medium without coalescence, and (2) after certain critical flow field conditions are, attained, the production of the microbubbles according to the pfesent'invention proceeds virtually independently of increasing gas flow rate or fluid velocity. In order to better distinguish the manner in which the present invention differs from that of prior processes, the nature of some of the commonly used techniques for producing gas bubbles will be briefly reviewed.

In the airstone principle, which is an extension of the technique of blowing bubbles through a plurality of capillary tubes, the gas stream is forced through a porous surface having a large numberof flow passages of very small diameter. The buoyant forces of the liquid medium above the airstone is utilized as thesole mechanism for detaching the bubbles from the surface. The size of the resultant bubbles, which is related to the flow rate of the stream, is not exceptionally small nor homogeneous, and it is rare for bubble sizes less than 1,000 microns in diameter to produced.

In order to improve the mechanism of bubble production by the airstone principle and to. obtain bubbles of smaller size, it has been conventional to impart a flow of relatively low velocity to the fluid medium in order to detach the bubbles away from the gas outlets and into the liquid. In such a system the viscous forces of the fluid flow shear the bubbles off of their gas outlets at a premature size, and the resultant bubble size is then a function ofboththe gas and liquid flow rates. However, as first recognized in the present invention, unless certain critical flow conditions are present in the fluid stream, homogeneous clouds of gas bubbles of microscopic size will not be consistently produced.

In the present invention, a turbulent boundary layer is established in a liquid flow passing over a suitable bubbleproducing surface, which may be in the form of a porous plate, cylinder, or the like having a large number of flow passages of sufficiently small diameter to permit production at the interface of bubbles of micron size. The liquid flow is made sufficiently turbulent such that an intense velocity gradient is present at the surface of the bubble. This produces pressure perturbations around the bubble which are of the magnitude necessary to overcome the relatively high interface forces securing the bubble to the surface. Detachment of the bubbles from the surface then occurs as a result of forces applied normal to the surface as the bubble responds to the random but highly frequent pressure variations in the turbulent boundary layer. However, and most importantly, in order to ensure the creation of bubbles of the desired microscopic size, it is critical that the laminar sublayer of film, which exists in the boundary layer of the liquid flow between the turbulent stream and the bubble-producing surface, have a thickness which is approximately equal to, but somewhat less than, the diameter of the desired microbubbles to be produced.

It is characteristic of the pres'entinvention that, once suitable conditions have been established for the production of microbubbles by the attainment of a satisfactorily high flow velocity in the liquid stream, the flow rate of the introduced gas may be increased independently without afiecting the size of the bubbles produced. Conversely, once the conditions of microbubble production are established, any increase in the velocity of the liquid flow similarly will not substantially affect the size or rate of production of microbubbles.

Control of the thickness of the laminar sublayer in the turbulent boundary layer of the fluid flow is the crucial parameter in determining the ultimate size of the produced bubbles. From empirical tests it has been determined that the thickness of this laminar sublayer should preferably be on the order of 0.9 of of the diameter desired for the resultant gas bubbles. While the growing bubble remains entirely in this region of laminar flow, which exists between the surface of the bubble producing gas outlets and the turbulent boundary layer of the fluid, itis subjected only to viscous shear stresses; however, once the hemisphere of the growing bubble enters into the region of the turbulent boundary layer, the bubble is then subjected to the severe and irregular pressure variations, normal to the surface wall, which are characteristic of turbulent flow and produced by the transfer of fluid masses between adjacent layers. These pressure perturbations serve to snap off the bubble from its gas outlet before further growth permits it to protrude to any substantial depth into the turbulent boundary layer.

In an exemplary embodiment of the presentinvention, apparatus has been provided for accomplishing the desired microbubble production by utilizing the boundary layer phenomena described above. Means are provided in the apparatus for controlling the flow rate of liquid past the bubbleproducing surface in order to establish the desired turbulent boundary layer and for regulating the thickness of the associated laminar sublayer. Once the predetermined critical flow conditions are established, the apparatus will then produce and disseminate into the. liquid stream dense, homogeneous clouds of very fine, microscopically sized gas bubbles.

It is therefore a principal objective of the present invention to provide apparatus for producing large, homogeneous quantities of extremely small, microscopically sized gas bubbles.

It is another objective of the present invention to provide apparatus for improving the intermixing of gases with liquids.

It is a characteristic feature of the present invention that a turbulent fluid flow stream is utilized to produce gas bubbles of extremely small size on the order of 5-10 microns in diameter.

It is another distinctive feature of the present invention that the size of the resultant gas bubbles is on the same order of magnitude as the thickness of the laminar sublayer present in the boundary layer of the turbulent fluid flow.

It is an important advantage that the size of the microscopically small bubbles produced by the process of the present invention is independent of both the gas flow rate and the velocity of the fluid stream, as long as certain boundary layer conditions, conditions are maintained in the fluid flow.

The foregoing and other objectives, features, and advantages of the present invention will be more readily understood upon consideration of the following detailed desc ription of the invention, taken in conjunction with the accompanying drawings.

FIG. 1 is a schematic diagram illustrating the boundary layer conditions present in the flow of a turbulent stream of liquid over a flat, smooth surface.

FIG. 2 is a schematic diagram, similar to FIG. 1, showing the progressive growth of bubbles from gas outlets in a porous plate.

FIG. 3 is a front sectional view, partially broken away, of an exemplary embodiment of apparatus for producing microbu bbles in accordance with the present invention.

FIG. 4 is a cross-sectional view, taken along the lines 4-4 in FIG. 3.

FIG. 5 is a sectional view, taken along the lines 55 in FIG. 3.

Referring now to FIG. 1, which will be useful for background purposes in understanding the fluid flow phenomenon utilized in the practice of the present invention, there is shown a velocity profile diagram of the boundary layer conditions which are present in the flow of a turbulent stream over a flat, smooth plate or boundary wall 10. As is presented by the curve 12, the velocity of the fluid at points along a vertical section of the flow is zero at the surface of the boundary wall and increases asymptotically to a constant value v in the laminar region 16 outside the turbulent boundary layer 11.

The fluid in the region 13 of the boundary layer immediately adjacent to the boundary wall 10 moves very slowly in parallel layers, and there is no transfer of fluid masses between adjacent layers in the flow. In this region 13, known as the laminar sublayer or film, the fluid flow is laminar in nature, its velocity gradient follows a linear relationship with increasing distance from the boundary wall 10, and the pressure differential is small and uniform within this sublayer.

However, at a certain distance or away from the boundary wall 10, a transition is made into the turbulent region 14 where there is a relatively high velocity flow with a continuous intermixture of fluid masses and transfer of momentum between adjacent layers. While, in this region 14, the fluid mass as a whole moves downstream with a steady average velocity, there are sharply fluctuating velocity components occurring in all directions. The flow pattern is unsteady, full of eddies, and apparently without any mathematically expressible regularity. These irregular and abrupt velocity fluctuations produce corresponding severe pressure variations within the turbulent region 14 of the fluid flow.

lt should be recognized that the transition or interface 15 between the laminar sublayer l3 and the turbulent region 14 of the boundary layer is not in actuality a sharply defined edge, as indicated in the diagram; however, for purposes of simplifying the explanation of the invention the assumption will be made that the transition from laminar to turbulent flow is made abruptly at the edge 15. Using a generally accepted approach in the art, i.e., the Karman-Prandtl equation for the velocity distribution in turbulent flow near smooth boundaries, the transition line 15 may be nominally defined by the intersection of two curves: a straight line curve representing the essentially linear nature of the velocity gradient in the laminar sublayer l3, and a logarithmic curve representing the more complex relationship between flow velocity and distance from the boundary wall in the turbulent region 14. (For a detailed description of the flow phenomena occurring in a turbulent boundary layer, as well as the mathematical treatment thereof, reference may be made to any one of a number of standard treatises in the field of fluid dynamics, such as, for example, Rouse, Elementary Mechanics of Fluids (Second Edition), Chapter VII, Wiley and Sons, New York, 1950.) Thus, as a generalization, it may be considered that flow in the fluid stream on the near side of the transition line 15 at distances of a or less away from the boundary wall 10 is laminar; while, on the other side of the line, the flow at distances greater that a is essentially turbulent in nature.

In FIG. 2 the fluid flow, schematically represented in FIG. 1, is now shown as passing over a porous plate or boundary wall 10 10' provided with a number of minute openings 20. These openings act as outlets for a gas stream supplied under pressure to the underside of the porous plate 10'.

As gas emerges from each of the outlets 20 and is introduced to the fluid streams, growing bubbles such as B, are formed on the upper surface of the plate 10. During the time that the growth of the gas bubble B, is relatively small and contained within the laminar sublayer 13 which exists in the region immediately adjacent the surface of the plate 10', the bubble will be subjected to only moderate shear and buoyant forces tending to detach it away from its outlet 20. If, for example, the fluid flow is comprised of water or other suitable liquid, the adhesive forces of surface tension produced at the gas-liquid interface of the bubble will be more than sufiicient to prevent its detachment during this time.

However, once the hemisphere of the growing bubble protrudes beyond the relatively tranquil flow of the laminar sublayer l3 and into the turbulent region 14 of the flow boundary layer, the bubble, shown at B is then subjected to extremely strong detachment forces which are normal to the surface 10 and produced by the severe pressure fluctuations present in this latter region. These forces, which are of much greater intensity than those encountered while the growth of the bubble was confined entirely to the laminar sublayer l3, pluck off the bubble, now shown as B;,, from its outlet 20 and thrust it into the flowing fluid stream before any significant amount of further growth is permitted to occur. Thus, the completed bubble B attains, at the instant of detachment from the surface 10', a size dimension d which is on the same order of magnitude as the thickness or of the laminar film 13. Since the laminar film in a turbulent boundarylayer is very thin and on the order of only a few microns in thickness, the size of the detached bubble B is similarly quite small, typically being in the range of 5 to 10 microns in diameter.

As the thickness at of the laminar sublayer 13 remains constant with time and does not vary significantly along the direction of turbulent flow over the boundary wall 10', all of the completed bubbles B formed by the above-described process will be of substantially the same diameter d, thus resulting'in the production of a homogeneous cloud of microscopically sized gas bubbles. Furthermore, since the thickness or of the laminar sublayer 13 decreases only slightly with increasing flow velocity in the turbulent boundary layer 11, any change in the velocity of the fluid stream will not substantially affect the size or rate of production of the resulting microbubbles, so long as turbulent flow conditions are maintained. Similarly, since the size of the completed bubbles B; at the point of detachment from the boundary wall 10 is dependent primarily on the thickness or of the laminar film 13, variation of the flow rate of the gas introduced into the fluid stream via outlets 20 will not produce any corresponding change in the size of the resulting microbubbles.

The comparative insensitivity of the resultant bubble size to large changes in the fluid and/or gas stream flow rates is a characterizing feature of the present process which dramatically differentiates it from the prior art methods of bubble production discussed previously. This distinctive aspect of the process permits a ready determination to be made as to whether the proper flow conditions have been established in a system for the production of microbubbles according to the principles of the present invention.

FIGS. 35 illustrate an exemplary embodiment of an apparatus which has been constructed for producing microbubbles in accordance with the present invention.

The apparatus 30 comprises a cylindrical sparger portion 35 having a porous surface 35' with an average pore diameter of 5 to 10 microns-a pore size which is slightly less than the size of th the resulting microbubbles to-be produced. The sparger 35 is mounted inside an outer shell member 34, the clearance between which is tapered inward toward the left-hand end of the apparatus for reasons that will hereinafter be explained. Of course, either the inner wall of the shell 34, as shown in FIG. 3, or the outer surface 35 of the sparger 35, may be configured to have the required taper. For construction and mounting purposes, the shell member 34 is in two parts flanged together at 26 with connecting bolts 26a and sealing gasket 26b. A set of longitudinally extending guide vanes 45, attached to the inner wall of the shell member 34 by fasteners 45a, maintain the cylindrical sparger 35 in a concentric relationship inside the shell member with a small tapered passageway 49 therebetween whose cross section, as shown in FIG. 4, is in the form of a segmented annular ring.

With fluid and gas flows both proceeding from left to right axisof the shell. Also at the upstream end of the apparatus, a fluid inlet pipe 32 is connected at right angles through joint 38 to the shell member 34.

At the right-hand, or downstream, end of the apparatus the sparger 35 is terminated in a hydrodynamically streamlined tail cone portion 36, and the shell member 34 converges at 34a into a discharge line connecter 37. Thus,.by longitudinal displacement of the sparger 35 through operation of the handwheel 42, the size of the flow passage 51 between the tail cone 36 and the converging walls 34a of the shell member may be adjusted, similar to a valve, to provide a flow control point downstream of the sparger 35 of for reasons which will be shortly explained.

As shown in FIG. 3, it the fluidflow from the inlet pipe 32 (representedby the solid arrows 31), after itenters the apparatus at joint 38 and makes a right-angled turn, then passes into the narrow annular passageway 49 which surrounds the body of the sparger cylinder 35. Due to this severe constriction in the cross-sectional area of the fluid flow as it travels through the annular passageway 49, boundary turbulent shear flow will be produced in'thefluid stream (assuming the fluid entering at inlet pipe 32 is of a suitable velocity).

As the turbulent flow proceeds through the narrow annular passage 49, it is intermixed, as shown in FIG. 5, with the gas stream from the inlet line 33 (represented by the dashed arrows 40) at the boundary wall presented by the porous surface 35' of the sparger. The combined fluid-gas flow stream (represented by the dotted-dashed arrows 50) then emerges at the downstream end of the apparatus 30 passing through the clearance space 51 around gthe tail cone portion 36 of the sparger and thereafter into the discharge line connecter 37 from where it is exhausted.

The purpose of providing a taper in the annular passageway 49 is to maintain the flow pressure constant along the length of the cylindrical body of the sparger 35. If the fluid-gas differential pressure in the flow passing over the porous surface 35' of the sparger body is not kept uniform, there will be the possibility that the gas will be injected into the fluid flow at too great velocity at some points,- or that, due to excessive fluid pressure, fluid will seep into the porous sparger at other points. Since the'gas flow40 inside the hollow sparger body is at essentially a constant pressure throughout it is therefore necessary to maintain constant as well the fluid pressure on the outside of the sparge gxin order that a uniform fluid-gas pressure differential exist along the length of the interface boundary surface 35'. I

In order to counteract the pressure drop in the fluid flow caused by friction as the fluid travels along the length of the sparger body, the cross-sectional area of the fluid flow is gradually increased in the downstream direction by means of the taper so that the consequent decrease in fluid velocity, due to the enlarging cross section, produces a pressure increase which just compensates for the-pressure decrease due to friction losses. (The amount of the taper which must be provided in the passageway 49 to achieve the desired degree of compensation can be readily calculated by known fluid dynamics techniques, taking into account the parameters of the flow system.)

In operation, with an illustrative set of flow parameters, the required turbulent flow conditions for the production of microbubbles according to {the present process may be established in the apparatus by the adjustment of the sparger in the maximum upstream position (i.e., to the left as shown in FIG. 3). By means of the adjustment provided by the handwheel 42, the sparger 35 is then slowly moved in the downstream direction (i.e., toward the right in H6. 3), moving the tail cone 36 closer to the converging walls 344. The constriction of the fluid flow in the tail cone region 51 will, in much the same manner as a valve, cause the flow of fluid 31 passing over the surface 35' of the sparger body to decrease, while the pressure head slowly builds up.

The placement of the low control point, which is provided by the valve action in the tail cone region 51, at a location downstream of the sparger body 35 is an important feature of the sparger design. If a flow constriction, having a smaller cross-sectional area than the minimum clearance area in the tapered annular passageway 49, is not provided downstream of the sparger body, then a differential pressure drop will occur in the fluid flow somewhere along the surface 35' of the sparger. This differential pressure drop will, under certain circumstances, move rapidly back and forth along the sparger surface 35' and will completely disrupt the formation of microbubbles according to the disclosed process. By movement of the sparger along the axis to control the area of constn'ction in the tail come region 51, and thereby causing the required pressure drop at a point downstream of the sparger body 35, a constant pressure along the entire surface 35' of the sparger body may be easily maintained.

As the pressure head in the fluid flow begins to increase sharply due to the constricted flow at the tail cone region 51, reaching 7-5 p.s.i. or so, the gas stream is then induced into the center of the porous sparger 35, via the inlet line 33, at a flow rate on the order of 600 standard cubic feet per hour. With the position of the sparger thus adjusted to produce a turbulent boundary layer over the surface of the cylinder, the bubbles of gas forming at the surface pores 35 or of the sparger 30 will be detached and swept into the fluid as soon as they project beyond the laminar sublayer of the flow, thus producing microbubbles in accordance with the process disclosed earlier. The gas flow 40 may thereafter be increased to any desired rate without affecting the production of microbubbles, the flow rate of gas being limited only by the crowding of attached bubbles during their formation on the porous surface 35' of the sparger 35. i

The narrow tapered passageway over the sparger body, together with the valvelike action provided by the axial adjustment of the sparger which establishes a flow control point for pressure head control downstream of the sparger body, enables the production of gas bubbles of microscopic size in the sparger apparatus 30 without the need for any external adjustment of the liquid or gas flow rates. The only limiting condition on the'operation of the apparatus is that the fluid flow rate must exceed a certain minimum value corresponding to the establishment of the necessary fluctuating turbulent flow field over the porous cylindrical body 35' of the sparger so that microbubbles will be produced.

The terms and expressions which have been employed here are used as terms of description andnot of limitation, and there is no intention, in the use of such terms and expressions, of excluding equivalents of the features shown and described, or portions thereof, it being recognized that various modification are possible within the scope of the invention claimed.

1 claim:

1. An apparatus for producing large homogeneous quantities of gas bubbles of microscopic size of 10 microns or less in diameter, comprising:

a. a bubble-producing surface having a plurality of gas outlets of smaller diameter than that desired of said resultant bubbles;

b. a surface opposing said bubble-producing surface and forming therewith a passageway for liquid flow;

c. means for passing a liquid flow therethrough at positive pressure; a

d. means for adjusting the velocity of said liquid flow in relation to said passageway to establish a turbulent boundary layer therein, said boundary layer being comprised of a turbulent region having severe and irregular velocity fluctuations therein and a laminar sublayer having a regular linear velocity gradient, said sublayer being situated beneath said turbulent region and adjacent said bubbleproducing surface and having a thickness comparable to the diameter desired of said resultant bubbles, said surfaces diverging in the direction of said flow to compensate for friction losses in said flow to maintain fluid pressure on said bubble-producing surface constant over its length; and

e. means for supplying a gas stream to the outlets on said bubble-producing surface, whereby gas bubbles forming on said surface are detached therefrom and carried into said liquid flow when the size of said forming bubbles begins to exceed the thickness of said laminar sublayer and to project into said turbulent region.

2. The apparatus set forth in claim 1 further including means for maintaining uniform the liquid-gas pressure differential at said bubble-producing surface by compensating for frictional losses in said liquid flow thereover.

3. The apparatus set forth in claim 1 further including means for controllably constricting said liquid flow at a position immediately downstream of said bubble-producing surface, thereby to prevent the creation of a differential pressure drop in said fluid flow at a location on said surface.

4. The apparatus set forth in claim 1, further including means for providing a flow control point in said liquid flow at a location downstream of said bubble-producing surface, comprising:

a. an end portion on said bubble-producing surface;

b. A convergence in said opposing surface in juxtaposition with said end portion to form an exit passage of reduced area for said liquid flow, and

c. means for displacing said bubble-producing surface along a line parallel to said liquid flow relative to said opposing surface for adjusting the size of the clearance space between said end portion and said exit passage.

5. An apparatus for producing large homogeneous quantities of gas bubbles of microscopic size of 10 microns or less in diameter, comprising:

a. a hollow sparger having a porous, cylindrical surface with an average pore diameter of 5 to microns in diameter;

b. cylindrical shell member coaxial with said sparger and having an inner wall greater size;

c. the arrangement of said sparger surface and the inner wall of said shell member forming an annular, narrow passageway therebetween;

d. means for supplying a pressurized stream of gas to the inside of said sparger for dispersion to the outside through the surface pores thereof; and

e. means for directing a liquid stream into said passageway at a pressure of at least 75 p.s.i. to establish a turbulent boundary layer over the surface of said sparger, wherein said annular passageway is provided with an increasing taper in the downstream direction of said liquid stream, the tapered increase in flow cross section producing a corresponding pressure increase in said liquid stream in the direction of flow which is sufficient to compensate for the pressure drop due to friction losses, whereby the liquid flow pressure over the surface of said sparger is maintained uniform.

An apparatus for produci ng large homogeneous quantities of gas bubbles of microscopic size of 10 microns or less in diameter comprising:

a hollow sparger having a porous, cylindrical surface with an average pore diameter of 5 to 10 microns in diameter; a cylindrical shell member coaxial with said sparger and having an inner wall of greater size;

the arrangement of said sparger surface and the inner wall of said shell member forming an annular, narrow passageway therebetween;

. means for supplying a pressurized stream of gas to the inside of said sparger for dispersion to the outside through the surface pores thereof;

means for directing a liquid stream into said passageway at a pressure ofat least 75 p.s.i. to establish a turbulent boundary layer over the surface of said sparger; and

. means for providing a flow control point in said liquid stream at a location downstream of said sparger surface, said means comprising, a streamlined tail cone portion atties of gas bubbles of microscopic size 10 microns or less in diameter, comprising:

a hollow sparger having a porous, cylindrical surface with an average pore diameter of 5 to 10 microns in diameter; a cylindrical shell member coaxial with said sparger and having an inner wall of greater size;

the arrangement of said sparger surface and the inner wall of said shell member forming a generally annular, narrow passageway therebetween;

means for supplying a pressurized stream of gas to the inside of said sparger for dispersion to the outside through the surface pores thereof;

means for directing a liquid stream into said passageway at a pressure of at least 75 p.s.i. to establish a turbulent boundary layer over the surface of said sparger; and

. means for providing a flow control point in said liquid

US3545731D 1966-11-08 1966-11-08 Apparatus for producing bubbles of very small,microscopic size Expired - Lifetime US3545731A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US59287266A true 1966-11-08 1966-11-08

Publications (1)

Publication Number Publication Date
US3545731A true US3545731A (en) 1970-12-08

Family

ID=24372392

Family Applications (1)

Application Number Title Priority Date Filing Date
US3545731D Expired - Lifetime US3545731A (en) 1966-11-08 1966-11-08 Apparatus for producing bubbles of very small,microscopic size

Country Status (1)

Country Link
US (1) US3545731A (en)

Cited By (41)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3711072A (en) * 1970-04-23 1973-01-16 D Waldenville Apparatus for oxygenation of liquids
US3927152A (en) * 1971-03-12 1975-12-16 Fmc Corp Method and apparatus for bubble shearing
US4022854A (en) * 1971-03-12 1977-05-10 Fmc Corporation Gas transmitting body for use in bubble shearing
US4024618A (en) * 1971-03-12 1977-05-24 Fmc Corporation Method of fabricating gas transmitting body for use in bubble shearing
US4073727A (en) * 1973-03-28 1978-02-14 Groupement Europeen De La Cellulose Process for the oxidation of waste liquors arising from the manufacture of paper pulp
US4105725A (en) * 1972-11-21 1978-08-08 Liquid Carbonic Canada Ltd. Saturated liquid/vapor generating and dispensing
US4116488A (en) * 1976-09-20 1978-09-26 Kennecott Copper Corporation In-situ mining method and apparatus
US4165286A (en) * 1977-01-17 1979-08-21 August Schreiber Apparatus for the intermittent aeration of sewage
FR2421671A1 (en) * 1978-04-05 1979-11-02 Alsthom Atlantique Generator of bubbles in liq. medium - with nozzle feeding liq. stream sweeping zone between nozzle and perforated gas emission surface, maximising distribution and dispersion
US4186094A (en) * 1976-04-12 1980-01-29 Swemac S.A. Apparatus for eliminating by flotation impurities in the form of solid particles contained in a liquid
US4360234A (en) * 1976-09-20 1982-11-23 Kennecott Copper Corporation In-situ method and apparatus for sparging gas bubbles
US4399028A (en) * 1982-06-14 1983-08-16 The Black Clawson Company Froth flotation apparatus and method
FR2590246A1 (en) * 1985-11-20 1987-05-22 Screg Routes & Travaux Device for the oxygenation of lagoon treatment effluents
EP0226495A1 (en) * 1985-11-15 1987-06-24 Canadian Liquid Air Ltd Air Liquide Canada Ltee Process and apparatus for bleaching paper pulp
US4717515A (en) * 1985-04-29 1988-01-05 Wilfley Weber, Inc. Apparatus for dispersing fluids in liquids
US4818447A (en) * 1987-04-27 1989-04-04 Kiyomoto Tekko Kabushiki Kaisha Apparatus for mass transferring between phases different from each other
US4895683A (en) * 1987-04-27 1990-01-23 Kiyomoto Tekko Kabushiki Kaisha Apparatus for mass transferring between phases different from each other
FR2642986A1 (en) * 1989-02-15 1990-08-17 Carboxyque Francaise Process and plant for producing a mixture of "freon" and carbon dioxide
US4961882A (en) * 1988-06-23 1990-10-09 Exxon Research And Engineering Company Fine bubble generator and method
US4971731A (en) * 1988-10-21 1990-11-20 Deister Concentrator Company, Inc. Method and apparatus for generating microbubbles in froth flotation mineral concentration systems
US5078921A (en) * 1988-10-21 1992-01-07 The Deister Concentrator Company, Inc. Froth flotation apparatus
US5194187A (en) * 1989-09-13 1993-03-16 Henkel Kommanditgesellschaft Auf Aktien Steam/water mixer
US5266240A (en) * 1991-03-20 1993-11-30 Servicios Corporativos Frisco, S.A. De C.V. Flotation reactor with external bubble generator
US5431286A (en) * 1994-01-06 1995-07-11 Inco Limited Recirculating column flotation apparatus
US5513722A (en) * 1995-03-10 1996-05-07 Foltz; Donald R. Compressed air lubricator
US5591328A (en) * 1990-11-23 1997-01-07 Atomaer Pty. Ltd. Gas particle formation
US6017022A (en) * 1995-10-12 2000-01-25 The Dow Chemical Company Shear mixing apparatus and use thereof
WO2006046202A1 (en) * 2004-10-29 2006-05-04 Koninklijke Philips Electronics N.V. Apparatus and methods for the production of ultrasound contrast agents
WO2007096443A1 (en) * 2006-02-22 2007-08-30 Universidad De Sevilla High-performance method and device for generating drops and bubbles
US20090000488A1 (en) * 2004-01-30 2009-01-01 Johann Magg Method and Electronic Control Device for Controlling Heating Processes in a Coffee Machine
US20090304449A1 (en) * 2003-12-24 2009-12-10 Kerfoot William B Directional Microporous Diffuser And Directional Sparging
WO2010149958A3 (en) * 2009-06-22 2011-03-24 Hydroventuri Limited Apparatus and method for introducing a gas into a liquid
USRE43350E1 (en) * 1995-05-05 2012-05-08 Think Village-Kerfoot, Llc Microporous diffusion apparatus
US8302939B2 (en) 2003-02-12 2012-11-06 Thinkvillage-Kerfoot, Llc Soil and water remediation system and method
US8557110B2 (en) 2000-07-06 2013-10-15 Thinkvillage-Kerfoot, Llc Groundwater and subsurface remediation
WO2014023861A2 (en) 2012-07-31 2014-02-13 Universidad De Sevilla Cross flow bubble generating device and generating method
US20140191425A1 (en) * 2011-12-16 2014-07-10 Panasonic Corporation System and method for generating nanobubbles
WO2017035110A1 (en) * 2015-08-25 2017-03-02 Cornelius, Inc Apparatuses, systems, and methods for inline injection of gases into liquids
US9694401B2 (en) 2013-03-04 2017-07-04 Kerfoot Technologies, Inc. Method and apparatus for treating perfluoroalkyl compounds
WO2017156410A1 (en) * 2016-03-11 2017-09-14 Moleaer, Inc Compositions containing nano-bubbles in a liquid carrier
WO2018191431A1 (en) * 2017-04-12 2018-10-18 Gaia Usa, Inc. Apparatus and method for generating and mixing ultrafine gas bubbles into a high gas concentration aqueous solution

Cited By (45)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3711072A (en) * 1970-04-23 1973-01-16 D Waldenville Apparatus for oxygenation of liquids
US3927152A (en) * 1971-03-12 1975-12-16 Fmc Corp Method and apparatus for bubble shearing
US4022854A (en) * 1971-03-12 1977-05-10 Fmc Corporation Gas transmitting body for use in bubble shearing
US4024618A (en) * 1971-03-12 1977-05-24 Fmc Corporation Method of fabricating gas transmitting body for use in bubble shearing
US4105725A (en) * 1972-11-21 1978-08-08 Liquid Carbonic Canada Ltd. Saturated liquid/vapor generating and dispensing
US4073727A (en) * 1973-03-28 1978-02-14 Groupement Europeen De La Cellulose Process for the oxidation of waste liquors arising from the manufacture of paper pulp
US4186094A (en) * 1976-04-12 1980-01-29 Swemac S.A. Apparatus for eliminating by flotation impurities in the form of solid particles contained in a liquid
US4116488A (en) * 1976-09-20 1978-09-26 Kennecott Copper Corporation In-situ mining method and apparatus
US4360234A (en) * 1976-09-20 1982-11-23 Kennecott Copper Corporation In-situ method and apparatus for sparging gas bubbles
US4165286A (en) * 1977-01-17 1979-08-21 August Schreiber Apparatus for the intermittent aeration of sewage
FR2421671A1 (en) * 1978-04-05 1979-11-02 Alsthom Atlantique Generator of bubbles in liq. medium - with nozzle feeding liq. stream sweeping zone between nozzle and perforated gas emission surface, maximising distribution and dispersion
US4399028A (en) * 1982-06-14 1983-08-16 The Black Clawson Company Froth flotation apparatus and method
US4717515A (en) * 1985-04-29 1988-01-05 Wilfley Weber, Inc. Apparatus for dispersing fluids in liquids
EP0226495A1 (en) * 1985-11-15 1987-06-24 Canadian Liquid Air Ltd Air Liquide Canada Ltee Process and apparatus for bleaching paper pulp
FR2590246A1 (en) * 1985-11-20 1987-05-22 Screg Routes & Travaux Device for the oxygenation of lagoon treatment effluents
US4818447A (en) * 1987-04-27 1989-04-04 Kiyomoto Tekko Kabushiki Kaisha Apparatus for mass transferring between phases different from each other
US4895683A (en) * 1987-04-27 1990-01-23 Kiyomoto Tekko Kabushiki Kaisha Apparatus for mass transferring between phases different from each other
US4961882A (en) * 1988-06-23 1990-10-09 Exxon Research And Engineering Company Fine bubble generator and method
US4971731A (en) * 1988-10-21 1990-11-20 Deister Concentrator Company, Inc. Method and apparatus for generating microbubbles in froth flotation mineral concentration systems
US5078921A (en) * 1988-10-21 1992-01-07 The Deister Concentrator Company, Inc. Froth flotation apparatus
FR2642986A1 (en) * 1989-02-15 1990-08-17 Carboxyque Francaise Process and plant for producing a mixture of "freon" and carbon dioxide
US5194187A (en) * 1989-09-13 1993-03-16 Henkel Kommanditgesellschaft Auf Aktien Steam/water mixer
US5591328A (en) * 1990-11-23 1997-01-07 Atomaer Pty. Ltd. Gas particle formation
US5266240A (en) * 1991-03-20 1993-11-30 Servicios Corporativos Frisco, S.A. De C.V. Flotation reactor with external bubble generator
US5431286A (en) * 1994-01-06 1995-07-11 Inco Limited Recirculating column flotation apparatus
US5513722A (en) * 1995-03-10 1996-05-07 Foltz; Donald R. Compressed air lubricator
USRE43350E1 (en) * 1995-05-05 2012-05-08 Think Village-Kerfoot, Llc Microporous diffusion apparatus
US6017022A (en) * 1995-10-12 2000-01-25 The Dow Chemical Company Shear mixing apparatus and use thereof
US8557110B2 (en) 2000-07-06 2013-10-15 Thinkvillage-Kerfoot, Llc Groundwater and subsurface remediation
US8302939B2 (en) 2003-02-12 2012-11-06 Thinkvillage-Kerfoot, Llc Soil and water remediation system and method
US20090304449A1 (en) * 2003-12-24 2009-12-10 Kerfoot William B Directional Microporous Diffuser And Directional Sparging
US8771507B2 (en) 2003-12-24 2014-07-08 Thinkvillage-Kerfoot, Llc Directional microporous diffuser and directional sparging
US20090000488A1 (en) * 2004-01-30 2009-01-01 Johann Magg Method and Electronic Control Device for Controlling Heating Processes in a Coffee Machine
WO2006046202A1 (en) * 2004-10-29 2006-05-04 Koninklijke Philips Electronics N.V. Apparatus and methods for the production of ultrasound contrast agents
US20090130025A1 (en) * 2004-10-29 2009-05-21 Koninklijke Philips Electronics, N.V. Apparatus and methods for the production of ultrasound contrast agents
US20090309244A1 (en) * 2006-02-22 2009-12-17 Universidad De Sevilla Procedure and device of high efficiency for the generation of drops and bubbles
ES2298020A1 (en) * 2006-02-22 2008-05-01 Universidad De Sevilla Method and device for high throughput generation of drops and bubbles.
WO2007096443A1 (en) * 2006-02-22 2007-08-30 Universidad De Sevilla High-performance method and device for generating drops and bubbles
WO2010149958A3 (en) * 2009-06-22 2011-03-24 Hydroventuri Limited Apparatus and method for introducing a gas into a liquid
US20140191425A1 (en) * 2011-12-16 2014-07-10 Panasonic Corporation System and method for generating nanobubbles
WO2014023861A2 (en) 2012-07-31 2014-02-13 Universidad De Sevilla Cross flow bubble generating device and generating method
US9694401B2 (en) 2013-03-04 2017-07-04 Kerfoot Technologies, Inc. Method and apparatus for treating perfluoroalkyl compounds
WO2017035110A1 (en) * 2015-08-25 2017-03-02 Cornelius, Inc Apparatuses, systems, and methods for inline injection of gases into liquids
WO2017156410A1 (en) * 2016-03-11 2017-09-14 Moleaer, Inc Compositions containing nano-bubbles in a liquid carrier
WO2018191431A1 (en) * 2017-04-12 2018-10-18 Gaia Usa, Inc. Apparatus and method for generating and mixing ultrafine gas bubbles into a high gas concentration aqueous solution

Similar Documents

Publication Publication Date Title
US3365242A (en) Apparatus for discharging a gas from a container at a constant rate through several conduits
Kirkpatrick et al. The influence of approach velocity on bubble coalescence
US4133773A (en) Apparatus for making foamed cleaning solutions and method of operation
US5018317A (en) Abrasive water jet cutting apparatus
US6065683A (en) Method and apparatus for conditioning fluid flow
US4441823A (en) Static line mixer
US3502103A (en) Inlet device for introducing water and oil in a pipeline
KR100389658B1 (en) Forming Emulsion
US4145173A (en) Film-forming head
US4353508A (en) Nozzle with pre-orifice metering restriction
US20030147303A1 (en) Cavitation mixer
US6802639B2 (en) Homogenization device and method of using same
CA1283651C (en) Gas dispersion process and system
US3719207A (en) Apparatus for transporting fluid
Vankova et al. Emulsification in turbulent flow: 1. Mean and maximum drop diameters in inertial and viscous regimes
US4721126A (en) Method of generating spiral fluid flow and the device therefor
Bourque et al. Reattachment of a two-dimensional, incompressible jet to an adjacent flat plate
US4752421A (en) Method of supplying air masses and producing jets of water
US2954750A (en) Mixer nozzle
US5542608A (en) Aspirating nozzles
US5615980A (en) Injector-feed device for pneumatic feed of powder
US3775307A (en) System for gas sparging into liquid
US3692245A (en) Fluid atomizers
US2751335A (en) Method and apparatus for mixing and contacting fluids
US5662811A (en) Method for creating gas-liquid interfacial contact conditions for highly efficient mass transfer