Abstract: An apparatus for preparing dispersions comprising a closed casing in the form of a bottomed hollow cylinder, a rotor disposed within the casing coaxially therewith and having a multiplicity of hard wire projections on the peripheral wall of the rotor, at least one liquid inlet pipe connected to one end of the casing, a dispersion outlet pipe connected to the other end of the casing and drive means disposed outside the casing at one side thereof for rotating the rotor at a high speed.

Abstract: Methods are provided for converting both plug flow and complete mix basins of the prior art into barrier oxidation ditches. Circulator/aerators are described that can be prefabricated and dropped onto the floor of an existing basin so that, in combination with at least one partition, if needed, an endless channel is created with minimum disruption of the activated sludge process.

Abstract: The invention relates to a process for improving the quality of mixing of liquid especially viscous media in stirred tank reactors, wherein a change in direction of the medium set in motion is brought about at one point or at several points of the inner wall of the reactor at different levels, in a direction vertical to the angle of approaching flow (attack). The process is especially suitable for fermentation reactions.The invention moreover relates to a corresponding stirred tank reactor.

Abstract: A process for separating a dispersed phase from a continuous phase comprising immersing vertically in the mixed phases an apparatus.

Abstract: An apparatus for mixing gas with liquid comprising:(a) an inner cylindrical member comprising an elongated tube having upper and lower ends and a plurality of turbines, which are free to rotate about their longitudinal axis, mounted within the tube, the turbines being spaced apart from one and another and so constructed that adjacent turbines have different rotational direction or velocity;(b) optionally, an outer cylindrical member comprising an elongated tube having upper and lower ends and a plurality of openings in the lower half of the tube wall;(c) a base member to which the lower ends of the outer and inner cylindrical members are attached so that the lower ends are sealed, the outer and inner cylindrical members being arranged in a concentric manner; and(d) a gas inlet pipe for introducing gas bubbles into the apparatus.The apparatus is useful for aerating sludge, separating the fine particles contained in a slurry, and separating particles having smooth surfaces from particles having jagged surfaces.

Abstract: A radial injector having a rotational disk through which gases are aspirated from the atmosphere and mixed with a fluid contacting the disk at the other side thereof. The disk is defining a ring slot by cooperating with a flange portion of the housing. Upon rotation of the disk, the fluid is accelerated towards the periphery of the disk thereby developing an undertow in the ring slot. Consequently gases are aspirated and injected into the fluid.

Abstract: A foam breaker for a fermentation reactor has one or more curved rods, preferably hollow rods with open ends (tubes), and an arrangement for so mounting these on the rotor of the reactor that they rotate with the rotor. The rods or the tubes have leading ends or inlets respectively which scoop up liquid of the liquid phase contained in the reactor, and opposite closed ends or outlets respectively at or through which this liquid is slung away or expelled in form of jets which pass through and destroy a layer of foam that forms above the liquid phase in the reactor.

Abstract: An apparatus for mixing a gas and a liquid is disclosed. The apparatus is comprised of a hollow outer tube and a hollow inner tube received coaxially within the outer tube. The inner tube is mounted for rotary motion within the hollow interior of the outer tube. A motor is attached to the outer tube adjacent a first end thereof and is drivingly coupled to a first end of the inner tube. The inner tube has a section which extends beyond the second end of the outer tube. A propeller is attached to this section of the inner tube for rotation therewith. The propeller is adapted to be placed in a liquid and to propel the liquid in which the propeller rotates. An inlet is formed in the inner tube for admitting a gas to the hollow interior of the inner tube. A diffusion tube forms a portion of the inner tube and extends beyond the propeller. The diffusion tube has a hollow interior which forms a portion of the hollow interior of the inner tube.

Abstract: The mixing impeller of the invention has a central, axial hub adapted for attachment to a rotatable driven shaft of a mixer motor. Mounted on the hub is a disc that extends radially from the hub. Circumferentially spaced around the disc are a number of impeller blades. Each blade has two different surfaces for mixing a liquid. One surface is flat and rectangular; the other surface is arrowhead-like, converging from the axial ends of the rectangular surface toward the middle of the rectangular surface of the next adjacent blade. When rotated at a given speed in a fluid in one direction, the impeller draws considerably less power than when rotated in the same fluid at the same speed in the opposite direction. Under certain operating conditions, the impeller has a higher mass transfer efficiency, in both directions of rotation when compared to other impellers. The blades of the impeller may be either open or closed, thereby further modifying the power characteristic of the impeller.

Abstract: In an apparatus for mixing gases with and dissolving gases in bodies of liquid there is an axial-flow pump impeller (22), which is arranged to raise the liquid through a substantially vertical riser line (20) whose lower end exhibits an inlet (15) for the liquid and whose upper end forms an outlet (11) for the pumped liquid and is defined by guide surfaces (7) arranged to deflect the liquid radially from the axis of the riser line (20), the drive shaft (4) of the impeller extending coaxially with the riser line from a drive unit, located above the said body of liquid, to the impeller (22), the improvement in which the drive shaft (4) is enclosed by a stationary line (16) whose inner wall together with the drive shaft (4) defines a gas-communication passage (17) whose lower end discharges into the riser line (20) via at least one outflow passage (19) directed substantially radially to the general center line, said gas-communication passage openly communicating with a gas source, such as the surrounding atmosph

Abstract: An efficient apparatus related in general to introducing gas into a body of liquid and more particularly to aerating wastewater contained in an activation basin by means of interacting surface agitation and gas entrainment.

Abstract: A design of a distribution unit allowing a gas or other material to be uniformly supplied to a mixing device close to the point of mixing. The distribution unit can be used for mixing chemicals into pulp at a refiner inlet.

Abstract: A provision of the disclosed grating composed of closed loops of plurality of parallelly-arranged straps with clearances between adjacent straps is made to encompass a space of a body of a revolution defined by a vane-type impeller. It proves to be effective for improving gas-absorption by a better gas-liquid contact in a chemical process or fermentation process.

Abstract: An automobile dirty smoke eliminator which mainly consists of two oval tin plates externally, and upper and lower exhaust pipes, left and right support plates, a blade, a discharge chamber, a discharge pipe, etc. internally. The principle of the present invention mainly consists in making use of the effect of mixing water and gas to entirely eliminate automobile dirty smoke. When the dirty smoke (exhaust gas) of automobile enters into the lower exhaust pipe of the present invention, the blade at the outlet of said lower exhaust pipe submerged in water is impacted by the compression force derived from the engine exhaust stroke so as to generate a mixture of said water and exhaust gas and to form a whirlpool having many buddles. The effect of walls of left and right support plates promote the toxin in the said dirty smoke (exhaust gas) automatically to deposit in the said water.

Abstract: An apparatus for mixing gas with liquid comprising:(a) an inner cylindrical member comprising an elongated tube having upper and lower ends and a plurality or turbines, which are free to rotate about their longitudinal axis, mounted within the tube, the turbines being spaced apart from one another and so constructed that adjacent turbines have different rotational direction or velocity;(b) optionally, an outer cylindrical member comprising an elongated tube having upper and lower ends and a plurality of openings in the lower half of the tube wall;(c) a base member to which the lower ends of the outer and inner cylindrical members are attached so that the lower ends are sealed, the outer and inner cylindrical members being arranged in a concentric manner; and(d) a gas inlet pipe for introducing gas bubbles into the apparatus.

Abstract: A method of and an apparatus for aerating and circulating a liquid in a vessel comprising utilizing a surface aerator and a bottom mixing rotor mounted on a hollow common shaft. The rotor entrains liquid and air into the hollow center of the common shaft from the liquid surface region and affects a downward two-phase flow in the hollow center. The gas-liquid mixture is subsequently injected into the liquid body through the channels of the rotor which communicate with the hollow center of the shaft. The discharged jet streams disperse the entrained gas bubbles throughout the liquid body and provide turbulent mixing in the bottom section of the vessel. The present invention not only provides sufficient bottom mixing but also enhances the mass transfer efficiency of the surface aeration by enriching the gas content in the surface layer of the liquid.

Abstract: Froth flotation apparatus with mechanical agitation and aeration. Impeliers and diffusers therefor which are more durable and less expensive than the state-of-the-art components.

Abstract: An aeration apparatus, which entrains gas and circulates liquid mass. The apparatus consists of vertical tubes and a pumping device beneath the vertical tubes, all of which are constrained by a flow-confining barrel. The suction force of the pump draws down the liquid surface through the vertical tubes which induces a vortex action in each tube, and entrains gas into the center of the vortices from the gas body above the liquid surface. The entrained gas mixes with liquid and flows downward through the flow-confining barrel and is dispersed into the liquid of the tank.

Abstract: An aerator device which includes a submersible unitized electric motor-pump assembly designed by a housing in which is an electric motor having a shaft projecting therefrom and carrying a pump impeller, a second housing having a liquid chamber in which is located the pump impeller, a first opening in the second housing through which the pump impeller is insertable into the liquid chamber, a second opening in the second housing in general axial alignment with the first opening through which liquid is drawn into the liquid chamber, first and second plurality of nozzles arranged in generally axially aligned pairs for directing a liquid discharge from the liquid chamber in generally radially outwardly directed streams to atmosphere, and an aerator chamber opening into individual aerator chambers between the pairs of nozzles for aerating the liquid prior to the discharge thereof into a body of water within which the device is adapted to be submerged.

Abstract: A method for aeration of pseudoplastic mixtures by providing an enclosure with H/D of 0.5-5.0, a vertical rotatable shaft having bubble shearing means with extending arms, upwardly injecting gas bubbles at radial locations, and repeatedly shearing the rising bubbles by the rotating arms.

Abstract: PCT No. PCT/US79/00224 Sec. 371 Date April 10, 1979 Sec. 102(e) Date April 10, 1979, PCT Filed April 10, 1979. An apparatus (10, 212) for mixing a gas and a liquid is disclosed. The apparatus is comprised of a hollow outer housing (22) and a hollow inner tube (24) received for rotary motion within the outer housing (22). A motor (61) is attached to the outer housing (22) adjacent a first end thereof and is drivingly coupled to a first end of the inner tube (24). The inner tube (24) has a support tube (214) which extends beyond the second end of the outer housing (22). Propeller blades (216) are attached to the support tube (214) for rotation therewith. An inlet (82) is formed in the inner tube (24) for admitting a gas to the hollow interior of the inner tube (24). The support tube (214) has a diffusion section (222) that extends below the propeller blades (216).

Abstract: An improved compact apparatus for gas-liquid contact and separation by precipitation of solids therein, which essentially comprises a splash separating section, a solid-gas-liquid contact section and a solid depositing section formed in a single reaction vessel, in which gas is blown into the vessel through a gas disperser having a gas outlet opened below the liquid surface in said solid-gas-liquid contact section and caused to undergo contact with the phase of a suspension forcibly circulated from said solid depositing section formed below said solid-gas-liquid contact section, whereby the precipitated solids are prevented from depositing the inner surface of the vessel and other attendant members.

Abstract: To introduce and mix fluids, particularly gas (air) with liquid, which is called sparging, an airfoil blade impeller is used for pumping the liquid and for introducing the fluid to be sparged into the liquid through holes in the suction surface of the blade. The airfoil blades are characterized by camber, thickness and location of holes which result in high stripping efficiency of the gas into the liquid without significant decrease in power use efficiency over conventional sparging systems.

Abstract: A rotor adapted to rotate about a rotary shaft and intended for displacing fluids characterized in that the rotor comprises at least two ridges arranged helically around a core part so that a sectional area at right angles to the axis of rotation comprises at least two lobes with intermediate pits, the depth of the pit measured between the core part and a tangential line to the two lobes one on each side of the pit concerned being at least equal to one third of the distance between the core part and the circle described by the point of a lobe furthest remote from the axis of rotation.

Abstract: A gas-liquid contacting apparatus for removing sulfur dioxide from a flue gas is provided which comprises a vessel for receiving therein a liquid aqueous absorbent in a continuous phase; gas sparger means having an opening means at one end thereof, the gas sparger means extending vertically from above the surface of the aqueous absorbent liquid and through the surface such that the opening means is positioned below the surface wherein the opening means comprises notch means formed in the side walls of the gas sparger means and an open end of the gas sparger means; air sparger means in the aqueous absorbent, below the gas sparger means; outlet means for the gas after it contacts the aqueous absorbent, the outlet means being located above the level of the aqueous absorbent; reactant inlet means into the vessel; aqueous absorbent inlet means into the vessel; and outlet means for the reaction products and spent aqueous absorbent.

Abstract: A rotating gas diffuser for shearing fine gas bubbles from the surface thereof when the diffuser is immersed in a body of liquid and rotated therein. The rotatable shaft of the diffuser carries a disk like member defining at least one gas plenum having a porous wall out of which gas introduced into the plenum can pass to form nascent gas bubbles which are then sheared off by the viscous shear forces exerted by the liquid in which the disk is rotating. Preferably both the top wall and the bottom wall forming the gas plenum or plenums are porous. The ratio of the overall diameter of the disk to the maximum thickness of the disk in the gas diffusing area occupied by the plenums is at least about 32:1. Improved results are obtained when this ratio is at least about 48:1, more improvement is obtained with a ratio of at least about 64:1, and still greater improvement with a ratio of at least about 128:1. The preferred value of the ratio is at least about 256:1.

Abstract: A centrifugal pump adapted for use in a fermenter is provided. The fermenter includes an outer vessel which has mounted therein a generally centrally located draft tube. A centrifugal pump is mounted adjacent to one end of the draft tube and is operably connected to a motor for rotation thereby. The centrifugal pump includes a plurality of vanes radiating outwardly from a region adjacent the center of rotation and cover members positions on opposite sides of the vanes. The vanes and cover members cooperate and define flow paths through which medium can be induced to flow due to the centrifugal forces created during rotation of the vanes. The vanes have a distance between respective side boundaries thereof which is less at a position inwardly of the outer disposed end of the vanes than at the outer disposed ends of the vanes.

Abstract: An apparatus for mixing a liquid and a gas in a tank includes a means for circulating the liquid in the tank and a sparge ring for dispersing gas into the tank. The circulating means includes a plurality of blades extending downwardly from a bottom surface of a disc so that rotation of the blades creates a suction area. The sparge ring introduces gas into the tank in a direction that bypasses the suction area to prevent the gas from flowing into the suction area. Preferably, the sparge ring has a discharge means with a radius that is larger than the distance from the center of the disc to the outer tips of the blades.

Abstract: An improved apparatus for generating finely divided particulate gas bubbles in a liquid. The apparatus includes an outer body with a hollow shaft and a cavity defining means carried by the shaft. The shaft is apertured for communication with a gas supply and the cavity is apertured for communication with a liquid supply. The outer body also carried an inner body which includes a shaft and a plurality of vanes. The shaft of the inner body is journaled for rotation within the hollow shaft of the outer body.

Abstract: An apparatus for introducing gas, e.g. atmospheric oxygen, into a liquid such as waste water or sewage comprises a plurality of ribs of airfoil cross-section and forming venturi nozzles which are first constricted and then widened in the direction of liquid flow. The ribs are formed with minute passages for introducing the gas into the liquid perpendicular to the direction of liquid flow across the ribs.

Abstract: A process is provided for treating waste water biologically and clarifying the biologically treated water; considerable economic advantage is obtained by conducting both the biological treatment and the clarification of biologically treated water in a single vessel rather than in separate vessels; it is further found possible to treat in this system water containing much higher concentration of waste; in the process the supply of oxygen to the biological reaction zone is carefully monitored to meet the biological oxygen demand and avoid the occurrence of undissolved oxygen in the form of gas bubbles in the biological reaction zone or the clarification zone; there is further provided improvements in oxygen dissolving devices rendering them especially suitable for the two zone treatment.

Abstract: A mixing and aeration impeller is comprised of a hub and a plurality of first flutes interspaced between and joined to a plurality of second flutes. The flutes are adapted to the hub and have troughs which begin proximate the hub and extend radially away from and angularly downward and upward away from a plane normal to a shaft to which the impeller is adapted. The flutes are preferably formed as one unitary structure and shaped in a periodic pattern which may be generally sinusoidal or trapezoidal in cross section normal to the radius of the impeller along the length of the troughs. The impeller includes means to receive compressed air from a source and means to exhaust the compressed air radially outward from the rim. The hub has means to receive the compressed air and to communicate it to a passage or gap formed in the flutes to transmit the air radially outward to the rim. The air is exhausted through a slot along the rim of the impeller. A shroud with radial fins may be positioned about the impeller.

Abstract: An aerator device for maintaining a high level of oxygen in live bait storage containers is disclosed. The aerator device comprises a cover for the container on which is mounted a suitable drive motor. The shaft of the motor extends downwardly through the cover and carries at its lower end an impeller which is driven by the motor at a high rate of speed to vigorously stir and aerate the water in the container. The upper portion of the shaft is enclosed by a housing which depends from the cover and extends down below the water level in the container. The lower end of the shaft and the impeller are surrounded by a relatively stiff screen having openings large enough to allow the free circulation of water, but small enough to prevent bait from reaching the impeller. Air inlets are provided on the cover and on the shaft housing to admit air to the interior of the housing.

Abstract: A flotation cell having a submerged screen for breaking up mineral-laden air bubbles to reduce refuse entrainment and a rotating rake to break up the surface froth to return mechanically entrapped refuse which has escaped the screen.

Abstract: An apparatus for producing an aromatic dicarboxylic acid by oxidizing a benzene derivative with molecular oxygen in the liquid phase in a lower aliphatic carboxylic acid as a solvent in the presence of an oxidation catalyst, wherein a starting material liquid e.g., a benzene derivative or a solution thereof in the lower aliphatic carboxylic acid, is fed into the liquid-phase reaction system in a uniformly dispersed state by being passed through a porous material causing the pressure of the starting material liquid just after passing through said porous material to drop more than about 1 kg/m.sup.2 in relation to the pressure of the starting material liquid just before passing through said porous material. The resultant aromatic dicarboxylic acid has high purity and has good color.

Abstract: A method for removing sulfur dioxide from flue gases by simultaneous absorption and oxidation in an aqueous absorbent. An enclosed body of an aqueous liquid absorbent for the sulfur dioxide is provided and the flue gas is sparged into an upper portion of the liquid absorbent to form a first zone thereof. An oxygen-containing gas is introduced into a lower portion of the liquid absorbent to form a second zone of the liquid absorbent that is below the first zone of the liquid absorbent and which has an apparent density that is higher than that of the first zone. The oxygen-containing absorbent from the second zone is circulated to the first zone near the point of the flue gas introduction and an alkaline material reactive with the sulfur dioxide in the liquid absorbent is introduced into the body of liquid absorbent thereby fixing the sulfur dioxide in the liquid absorbent in the form of a sulfate. The sulfate is subsequently removed from the body of aqueous liquid absorbent.

Abstract: The disclosure is of a device comprising a submersible electric motor-pump assembly, a substantially annular inner chamber closely surrounding said pump and connected to the delivery thereof, a substantially annular outer chamber surrounding said inner chamber, an air supply conduit connected to said outer chamber, and a plurality of nozzle elements constituting ejector nozzles in the boundaries of said inner chamber and said outer chamber whereby liquid escapes from said inner chamber and entrains air from said outer chamber and is discharged in the form of aerating jets.

Abstract: A method of aerating slurry involves the use of a screw conveyor operating in a tubular casing having an inlet and an outlet. The inlet has access to the air above the level of the slurry so that as the conveyor is rotated air is admitted through the inlet and discharged at the outlet, which is below the surface level, into the body of the slurry. The screw conveyor may be in two portions of opposite hand so that one portion discharges air and the other portion discharges slurry at a common outlet intermediate the two ends of the casing.

Abstract: A machine for making an emulsified product from a mixture of a gas and a liquid milk product capable of forming a foam which comprises a fixed whipping barrel, having a substantially labyrinth passage defined therein, and to which the liquid milk product, after having sucked by and mixed with the gas in a suction pump, is supplied under pressure. The liquid milk product mixed with air is emulsified as it flows through the labyrinth passage in the fixed whipping barrel and then supplied towards a rotary whipping barrel having therein a stirring rod rotatable about its longitudinal axis. The emulsified milk product is, during its passage through the rotary whipping barrel, stirred by the rotary stirring rod so that it can be further emulsified to provide a highly homogenized emulsion which is subsequently discharged from a dispenser.

Abstract: Disclosed is an aeration device for aerating liquids having a foam-forming tendency. The amount of foam generated by such an aeration device is controlled by having the air inlet disposed at a predetermined foam level. The liquid inlet is disposed near the surface of the liquid to be aerated, such that solid particles floating thereon are taken into the aerator. Air and liquid are combined in the aeration device producing the desired foam. The foam level is prevented from exceeding the level of the air intake due to the fact that air is required to produce the foam, and if the foam level exceeded the air intake, it would be ingested into the pump reducing the amount of foam produced thereby. Particular embodiments disclose concentric foam and liquid intakes to a submersible aeration pump.

Abstract: An apparatus for introducing air into a liquid including an aerator housing having inner and outer walls defining an inner pressure chamber and an outer air chamber with jet nozzles being carried by the inner walls and opening radially outwardly for directing liquid jets from the pressure chamber through the air chamber, catching nozzles carried by the outer wall and opening outwardly therefrom in alignment with the jet nozzles for receiving a combined liquid and air flow therefrom, a driven liquid pump in the pressure chamber and a compressed air generator driven by a motor and carried thereby, and an air conduit leading from the compressed air generator into the air chamber.

Abstract: A gas-liquid contact apparatus for contacting gas with liquid by dispersing air to form fine air bubbles in the liquid power with minimum consumption of power which comprises: a vessel in which liquid held; a perforated pipe with a plurality of apertures through which gas is ejected into the liquid; and a rotor with blades radially attached thereto within the vessel, each blade of which is positioned in parallel to the axis of the perforated pipe and passes in proximity to the apertures so that gas is sheared by said rotating blades immediately after it is ejected from the apertures.

Abstract: The present invention relates to an apparatus for the controlling of froth during the aeration of liquids.In the aeration (or treatment with gas) of sewage for the biological (or chemical) purification of the latter it is well known that considerable frothing occurs, which cannot be immediately controlled even with considerable effort and expense, for example using froth skimmers, froth barriers, oversize tanks, and the like. The problem is in providing an aeration apparatus which, without additional measures, that is to say by its own resources, is able to control frothing and thus keep it within permissible limits.The expressions "aeration" and "air" are here used to refer to any gaseous medium which is to be admixed with any liquid concerned in the present context. Similarly the expression "air pipe" is to be understood as meaning a pipe for a gaseous medium.

Abstract: An apparatus for introducing gas, e.g. atmospheric oxygen, into a liquid such as waste water or sewage comprises a plurality of ribs of airfoil cross-section and forming venturi nozzles which are first constricted and then widened in the direction of liquid flow. The ribs are formed with minute passages for introducing the gas into the liquid perpendicular to the direction of liquid flow across the ribs.

Abstract: An aerator in which air is forced into the liquid by means of a helical rib surrounding a cylindrical member which is rotated in such a direction that air trapped beneath the helical rib is forced downwardly into the liquid. A diffuser at the bottom of the helical rib is effective to break up the trapped air bubbles into finer bubbles which are dispersed through and retained by the liquid. The cylindrical member on which the helical rib is disposed may be rotated by an electric motor which may be disposed either above the water line or beneath the water line at the bottom of the helical rib. Where necessary, air may be pumped into the space above the water so as to facilitate the introduction of air about the helical rib. Where the aerator is to be used with a container of limited size, the aerator may be either mounted on the cover of the container or may have associated therewith a closure member adapted to fit into the neck of such a container.

Abstract: A storage tank for liquid suspensions is shown, requiring sparging or agitation to prevent settling or salting out of somewhat insoluble suspended solids wherein the agitation is provided by movable high energy jets produced by nozzles that direct streams of compressed gas toward and under the precipitated agglomerations of solid particles. The apparatus includes means for distributing the energy of the compressed gas evenly over the surface area upon which the precipitate is deposited whereby to apply the needed agitation to all areas covered by deposits. The invention includes structural aspects for mounting the sparging apparatus on the top of the tank and suspending the moving agitators to extend downwardly into the tank to a position over the floor of the tank upon which the salting out takes place.

Abstract: The apparatus includes a central cylindrical element 1, extended, at its upper part, by a hopper 2, in the shape of a truncated cone ending in a roughly ovoid carter of a substantially spiral cross-section 3, extended by an air inlet 6, while the lower part of the tube forming the main body of the apparatus has the shape of a truncated cone 7 ending to a horizontal crown 8, located above a reaction plate 9, a rotating element 10-20 being located in the lower part of the main element, forming the body of the apparatus.

Abstract: An oxygenating centrifugal pump is primarily for circulating the aerated water in a culture pond for improving water quality. The centrifugal pump generally comprises a flat-bottomed cuplike vessel having a pair of floaters for floating said pump on a water and a plurality of pipy legs for locking the vessel in a bottom of the pond. An inner hollow cylinder closed at its top end is longitudinally and rigidly mounted through a bottom wall of said vessel, an umbrella-shaped diffuser is secured to a lower periphery of said cylinder and a motor driven shaft having an impeller at its lower end portion is longitudinally mounted in said cylinder to define a diffusing passageway between said diffuser and impeller.

Abstract: In a device for dispersing gas, e.g., air into a liquid or slurry in motion, wherein the surface at which dispersing takes place has a vertical extension and thus is subjected to varying hydrostatic pressure effected by the liquid or slurry, dispersing is optimized and the performance essentially improved by compensating the varying hydrostatic pressure with a dynamic pressure caused by the liquid in motion and varying in a desired manner so that the total pressure at least at most of the dispersing surface is substantially equalized. Said compensating is effected by providing for the correct flow rate and corresponding shape of the dispersing surfaces and other possible members influencing the liquid flow. In one embodiment the dispersing surface is represented by the envelope surface of a rotor rotating about a vertical axis.

Abstract: BOD-containing water such as sewage is mixed with active biomass and a first quantity of oxygen feed gas in a first cycle for biochemical oxidation to produce oxygenated liquid-solid and unconsumed oxygen-containing gas of lower purity than the feed gas. The unconsumed oxygen is discharged and a second quantity of oxygen feed gas is introduced for mixing in a second biochemical oxygenation cycle.