Abstract: A cavitation reactor that may be obtained from a centrifugal pump is described. The reactor comprises a stator and a rotor having at least one centrifugal stage accommodated in a chamber of the stator. Two walls of the centrifugal stage define a gap therebetween, which is divided into compartments in fluid communication with the chamber of the stator at the peripheral portion of the centrifugal stage. The wall of the centrifugal stage that is next to the inlet opening of the chamber of the stator is closed at the central portion of the centrifugal stage, to thereby prevent the flow of fluid from the inlet opening to the peripheral portion of the centrifugal stage through the gap.

Abstract: A cavitation device is supplied by a disc pump with fluids for mixing. A cavitation rotor, having an array of cavities on its cylindrical surface, is fixed to a shaft for rotation by a motor. The disc pump and the cavitation device are beneficially in the same housing. At least one disc is spaced from and attached to the rotor near the inlet end of the cylindrical housing, so it will rotate with the rotor. A central hole in the (at least one) disc permits fluid to enter the space between the disc and the rotor; it is flung toward the peripheral space between the rotor and the cylindrical housing, where it is subjected to cavitation, and then passed to an outlet. The shaft may pass through one or both of the end walls of the cylindrical housing. The cavitation pump is especially useful for mixing oil field fluids.

Abstract: A blender apparatus is disclosed having a chassis, a mixer positioned on the chassis, and a transfer pump positioned on the chassis. The mixer has a mixer housing defining a first mixer inlet, a second mixer inlet, and a mixer outlet. The first mixer inlet receives a liquid component, and the second mixer inlet receives a dry component. The mixer pressurizes at least the liquid component within the housing and discharges the liquid component through the mixer outlet at a first pressure above hydrostatic pressure. The transfer pump has a pump housing defining a pump inlet, a pump outlet and is devoid of an inlet configured to receive a dry component through a gravity feed. The transfer pump receives the liquid component through the pump inlet, pressurizes the liquid component within the pump housing, and discharges the liquid component through the pump outlet at a second pressure above hydrostatic pressure.

Abstract: A rotary emulsification device structure includes a housing, a emulsification element and a rotary disk. The housing includes a chamber with a first inlet, a second inlet and an outlet. The emulsification element is disposed in the chamber and divides the chamber into a first space and a second space. The first inlet is disposed to communicate with the first space, and the second inlet and the outlet are disposed to communicate with the second space. The emulsification element includes a plurality of pores communicating with the first space and the second space. The rotary disk is disposed in the second space and rotates in the second space when being driven. The rotary disk includes a plurality of through holes.

Abstract: A fluid mixing system including, an upper assembly, comprising a submersible pump housed therein; a base assembly connected to the upper assembly, the base assembly comprising one or more diffusers connected to opposing end portions of the base assembly; and a fluid path fluidly connecting the upper assembly and base assembly, wherein the fluid path extends from an outlet of the submersible pump to the one or more diffusers, and wherein the one or more diffusers are configured to provide a fluid outlet from the fluid path to create movement of fluid within a fluid reservoir.

Abstract: Submersible pump which comprises: a first motor provided with a first outlet shaft; a pumping body in which an impeller is housed that is fixed to the first outlet shaft of the first motor and drivable by the latter in order to pump a process fluid from a suction mouth to a delivery mouth of the pumping body itself; a support casing fixed to the pumping body and provided, at a lower end thereof, with an inlet opening through which a flow of the process fluid is susceptible to enter into the support casing itself; a dispersion head arranged at the lower end of the support casing and drivable in order to remove detrital material, which is conveyed by the flow of the process fluid into the inlet opening of the support casing.

Abstract: The invention relates to a dispersing rotor for homogenizing free-flowing media. According to the invention, the rotor-toothing formation forms a labyrinth toothing formation for a medium passing radially outward. The invention allows effective homogenization of free-flowing media by this rotor alone, without interaction with a stator-toothing formation being necessary.

Abstract: Blending particulate and liquid to make slurry for use in oilfield operations is addressed. The blender has an upwardly facing particulate expeller with a flat base, raised hub, and generally radially extending, circumferentially spaced vanes extending upwardly from the base. The vanes extend from leading edges spaced about a vane inner diameter to tips spaced about a vane outer diameter. Adjacent expeller vanes define expeller passageways therebetween. The particulate expeller does not serve as a meaningful liquid impeller and the blender does not act significantly as a pump. The expeller has a several preferred diameter, clearance, height and length dimensions and ratios. Wide, deep expeller inlets and shallow, narrow outlets enhance particulate entry and minimize expeller torque. Vane extensions impart velocity to the particulate upon contact and minimize sensitivity to particulate entry velocity. Maximized circumferential overlap of adjacent vanes reduces liquid back-flow.

Abstract: A centrifugal pump that includes a casing in which an impeller is arranged. The impeller has a back side that faces a back plate of the centrifugal pump, and one or more vanes for pumping the fluid. The back side of the impeller includes a segmented scraper for scraping from the back plate material that has been deposited from the fluid. The segmented scraper includes multiple protrusions, wherein each protrusion of the multiple protrusions is facing the back plate, and an aggregated radial extension of the protrusions equals a radius of the impeller within an interval of ±10%, ±25% or even up to ±40%.

Abstract: A rotor/stator type mixer implements the particle size breakup apparatus and includes a stator having a plurality of openings formed thereon and a rotor disposed on the inside of the stator and spaced away from the stator with a specific gap. The rotor, which is disposed inwardly of the stator having the plurality of openings formed thereon so that it can be spaced away from the stator with the specific gap, has a rotor peripheral wall that faces opposite the inside of the stator peripheral wall and is disposed inwardly radially of the peripheral wall of the stator having the plurality of openings formed thereon so that it can be spaced away from the stator with the specific gap. In addition, the rotor has a plurality of openings formed thereon.

Abstract: A method and apparatus for blending liquids and granular materials in which an impeller assembly is mounted for rotation within a housing at a lower end of a particles inlet and circumferentially spaced impeller vanes in outer concentric relation to a series of expeller vanes surrounding the particles inlet and which together propel the solid particles outwardly to intermix with the liquid introduced into the annulus surrounding the impeller assembly, the annulus being tapered or reduced in area in a direction counter to the direction of slurry flow in order to boost the pressure of the slurry discharged through an outlet port.

Abstract: A fluid is processed between processing surfaces capable of approaching to and separating from each other, at least one of which rotates relative to the other. A first fluid is introduced between processing surfaces, by using a micropump effect acting with a depression arranged on the processing surfaces from the center of the rotating processing surfaces. A second fluid, independent of this introduced fluid, is introduced from another fluid path that is provided with an opening leading to the processing surfaces, whereby the processing is done by mixing and stirring between the processing members.

Abstract: A technique facilitates mixing operations by removing foaming that results from air entrained during mixing of constituents. A mixing system comprises a container body having an interior and an inlet through which material enters the interior for mixing. The container body also comprises a discharge through which the mixed material is delivered downstream. A mechanical foam breaker is disposed within the container body and extends upwardly a sufficient distance to extend through a surface level to which the material rises during mixing within the container body. The mechanical foam breaker is oriented to break down foam along the surface of the material as the material moves through the interior.

Abstract: A novel apparatus is disclosed which comprises: (a) pumping means for injecting a fluid through a conduit means into an inlet pipe of a fluid mixing tank, (b) said fluid mixing tank comprising a plurality of compartments connected in series and in fluid communication with adjacent compartments in the series, and designed to provide for a horizontal flow of fluids from the first compartment to the last compartment in the series, (c) at least one compartment being equipped with one or more radial-flow impellers connected to a vertical shaft, and means for rotating such impellers at a rate designed to stir the contents of the compartment radially with high shear and prevent fluid stagnation, (d) at least one compartment being equipped with one or more axial flow impellers connected to a vertical shaft, and means for rotating such impellers at a rate designed to circulate the contents of the compartment vertically, (e) the inlet pipe being designed to introduce fluids into the first compartment, and (f) a means

Abstract: A device for accelerating mixing and dissolving processes of liquid water and powder. The device includes a main body formed in a bottle cap shape including a top surface and a side periphery surface, and a shaft disposed at a center of an upper portion of the main body in such a manner as to be inserted into a shaft insertion groove formed at a center of an impeller. The top surface of the main body has two or more introducing portions to introduce the liquid water and the powder into the device, and the side periphery surface of the main body has two or more discharging portions to discharge the liquid water and the powder introduced into the device through the two or more introducing portions to the outside of the device.

Abstract: The present invention is directed to an in-line mixer for mixing a plurality of fluids to produce a mixed product. The mixer includes one or more mixing chambers, an impeller in each of the mixing chambers, one or more inlets coupled to injection valves for conveying the fluids into the mixing chamber, and an outlet for conveying the mixed product out of the mixing chamber. The in-line mixer is well suited to components, such as those used in making automotive OEM and refinish paints.

Abstract: The present invention is directed to an in-line mixer for mixing a plurality of fluids to produce a mixed product. The mixer includes one or more mixing chambers, an impeller in each of the mixing chambers, one or more inlets coupled to injection valves for conveying the fluids into the mixing chamber, and an outlet for conveying the mixed product out of the mixing chamber. The in-line mixer is well suited to components, such as those used in making automotive OEM and refinish paints.

Abstract: The present invention relates to a device with a rotating fluidized bed in one or a succession of cylindrical chambers, in which injectors (12), distributed around the fixed circular wall (2) of said cylindrical chamber(s), inject along this wall, in successive layers, one or more fluids (13), which entrain the solid particles (17), passing through this/these chamber(s), in a movement of rapid rotation whereof the centrifugal force concentrates these particles along this wall, thereby forming a fluidized bed rotating around a central duct or a plurality of central ducts (3), through which the fluids are removed. The present invention further relates to a method of catalytic polymerization, drying or other treatments of solid particles in suspension in a rotating fluidized bed or of catalytic conversion of fluids passing through said rotating fluidized bed using a device according to the present invention.

Abstract: The present invention provides methods and apparatus for the separation of volatile components from a feed material.

Abstract: An apparatus for transporting and mixing materials includes a horizontally disposed container supported by a trailer, a motor mounted on the outside of the container, a shaft coupled to the motor and horizontally disposed in the container, and a mixing pedal coupled to the shaft and horizontally disposed in the container. The apparatus may include adjustably angled mixing pedals, and also adjustably angled fins. The apparatus may include a second chamber in the container including a second motor, a second shaft and a second mixing pedal. The apparatus may include a centrifugal pump for moving fluids into and out of the two chambers, as well as between the two chambers. The centrifugal pump may also power the two motors hydraulically.

Abstract: A method of processing a fluid and/or a particulate material, the method comprising the steps of: (a) introducing the particulate material into a chamber; (b) providing a flow of fluid into said chamber for entraining the particulate material; and (c) removing processed fluid and/or particulate material from the chamber; wherein the chamber comprises a processing zone having a substantially circular transverse cross-section, the fluid flow being introduced into the processing zone at an angle of between 10° and 75° with respect to a tangent of the substantially circular transverse cross-section of the processing zone to establish a fluid flow following a substantially helical path in the processing chamber.

Abstract: A device and method of transporting and blending substances into a container of fluid.

Abstract: A multistage process for the continuous production of an emulsion comprising subjecting at least two immiscible liquids to a sequence of at least two mixing stages carried out in at least two successive stator-rotor devices, wherein a peripheral outlet from a first stator-rotor device is connected to an axial inlet in the successive stator-rotor device by means of a duct in which the Reynold number ReT inside said duct is higher than 5000, and the peripheral velocity of each rotor of said stator-rotor devices ranges from 5 to 60 m/s.

Abstract: The device of the invention includes the following 5 new elements in each mixer-settler: a) agitators with blunt edged turbines, b) decreasing degree of agitation throughout the series of mixing compartments, c) baffle with a central window in the settler interface, located after the flow buffers, and d) baffle without a window, centered in the settler interface, located after the baffle with a window. These elements allow for an operative method which inhibits secondary dispersion, reducing the formation of micro-droplets, without affecting the mass transfer between the phases. Consequently, this obtains a phase separation process with entrainments so small that it is possible to drastically increase the quality of the product, by obtaining an ultra-pure aqueous extract, simultaneously reducing the settling surface required.

Abstract: An apparatus is disclosed for the production of frozen ice-cream mass with solid ingredients, which in the finished ice-cream mass will appear substantially as inclusions which distinguish themselves by flavour, appearance and/or consistency from the surrounding homogenous ice-cream mass. The apparatus comprises a first through-flow freezer for cooling of a continuous flow of mass, and a second through-flow freezer for further cooling of the continuous flow of mass, where a mixing-in arrangement for the mixing of solid ingredients into the continuous flow of mass is inserted between the through-flow freezer and the second through-flow freezer. It is hereby achieved that the mixing-in of the solid ingredients takes place in the frozen ice-cream mass when this has a temperature between ?3° C. and ?7° C. at which the viscosity of the mass is low.

Abstract: A high-speed turbine mixer combines water and cement into a pre-mixed cement paste that is added to aggregates to create a concrete mix. The turbine mixer includes a housing that cooperates with an auger to move dry cement into a mixing chamber where water is added. A mixing plate rotates at high speed to break up water and cement into small particles that enhances the hydration of the cement and increases the air content in the resultant cement paste. The cement paste is then conveyed to a mixing auger to be combined with aggregates to create a concrete mix. The mixing plate divides the mixing chamber to force the mixing water and cement particles to pass through a circumferential annular opening past agitating fins. Admixtures can be added to the cement as a powder or to the water as a liquid for incorporation into the cement paste.

Abstract: The present invention provides for a cavitational mixing and/or pumping device and method including a body having a base portion and a peripheral wall extending from the base portion and defining an inlet space therebetween. Additionally, the base portion includes at least one inlet port disposed therein that is in fluid communication with the inlet space. The peripheral wall includes an outlet channel disposed therein that is in fluid communication with the inlet space. A cavitation assembly is disposed within the outlet channel. Alternatively, a plurality of cavitation assemblies may be disposed within the outlet channel.

Abstract: The disclosed apparatus includes a stator and a rotor disposed for rotation within the stator. An inner wall of the stator defines one or more collider chambers. Rotation of the rotor causes movement of fluid disposed between the rotor and stator and establishes a rotational flow pattern within the collider chambers. The fluid movement induced by the rotor increases the temperature, density, and pressure of the fluid in the collider chamber.

Abstract: A processing apparatus for fluid with a simple structure, high productivity, ability of precise dispersion, emulsification and grinding, is provided.

Abstract: A method and apparatus for heating cellulose pulp with steam are provided. Low-pressure (e.g. 3-5 bar (abs.)) steam is supplied into the pulp flowing as a plug flow in such a way that in the flow direction of the pulp, before supplying the low-pressure steam, the pulp is pressurized so that the pulp pressure at the point of the steam introduction is lower than the pressure of the available steam. After the steam is introduced the pulp is mixed with a pressure-raising mixer (such as a fluidizing centrifugal pump) to divide the steam evenly into the pulp and/or to equalize the temperature of the pulp.

Abstract: Mixing systems including a radial impeller assembly positioned adjacent a flow opening of a tank are described.

Abstract: A stirring blade unit includes a perforated cylinder formed around the an internal stirring blade so as to be rotated together with the stirring shaft. The perforated cylinder has perforations which are approximately 30 to 50% of the area of the top and bottom surface of the perforated cylinder. The internal stirring blade unit uses a discharge type stirring blade unit used for gas-liquid mixing of a general fermentation tank. Thus, the gas-liquid flow discharged from the blade unit in the horizontal direction hits the perforated cylinder formed around the blade unit certainly. Due to this hitting of the gas-liquid flow against the perforated cylinder, the pressure of the flow is changed significantly to refine the gas bubbles so that the gas absorption property is improved. The stirring blade unit is suitable for gas-liquid mixing necessary for such as, fermentation, aeration, and reaction (hydrogenation and oxidation) tanks.

Abstract: A slurry mixing apparatus has a mixing chamber, a rotatable bearing and several blades. The bearing is connected to one end of each of the blades and located in the center of the mixing chamber. Several kinds of the slurries can be mixed rapidly in the apparatus and flowed into the CMP polisher immediately to perform a CMP process. Being mixed by the mixing chamber, the slurry is supplied to the chemical mechanical polisher for polishing.

Abstract: The disclosed apparatus includes a stator and a rotor disposed for rotation within the stator. An inner wall of the stator defines one or more collider chambers. Rotation of the rotor causes movement of fluid disposed between the rotor and stator and establishes a rotational flow pattern within the collider chambers. The fluid movement induced by the rotor increases the temperature, density, and pressure of the fluid in the collider chamber.

Abstract: A blender apparatus specifically adaptable for intermixing solid and liquid materials is made up of a housing for an impeller assembly having upper and lower impeller portions and wherein liquid directed into the lower impeller portion is redirected axially into the upper impeller portion for intermixing with solid materials directed into the upper impeller portion and undergo outward radial movement through the upper impeller portion into an outer peripheral area surrounding the impeller portions for subsequent discharge therefrom.

Abstract: Device for aerating and/or mixing water in a basin, using a means to impart a rotational motion to the water and having guide means (57) which convert the rotational motion into a combined horizontal and vertical motion of the water. Said guide means can be screw-shaped or plate-shaped elements of suitable shape and dimensions.

Abstract: A rotatably driveable enhanced-flow impeller system is provided for pumping at least one liquid in a tank through an outlet port thereof. A radial flow impeller has a first impeller face disposed proximate the bottom of the tank and proximate or extending into an inlet port for liquids in the tank bottom. The radial flow impeller has a plurality of blades with radially outermost blade tips terminating along a blade terminating circle. Disposed adjacent a second opposing face of the radial flow impeller is a radial flow extension plate which preferably extends radially outwardly along the second face by a radial distance beyond the blade terminating circle. The radial flow extension plate may be fixedly attached to the second impeller face.

Abstract: A rotatably driveable enhanced-flow impeller system has a radial flow impeller with a first impeller face disposed proximate the bottom of the tank and proximate or extending into an inlet port for liquids in the tank bottom. The radial flow impeller has a plurality of blades with radially outermost blade tips terminating along a blade terminating circle. The blades and inlet port are contoured to reduce shear stress on the liquids. Disposed adjacent a second opposing face of the radial flow impeller is a radial flow extension plate which preferably extends radially outwardly along the second face by a radial distance beyond the blade terminating circle. The radial flow extension plate may be fixedly attached to the second impeller face.

Abstract: A method and apparatus for mixing solid and liquid components of a slurry which have settled in a storage tank, suspending the solids in a substantially homogeneous slurry mixture are practiced by directed flow apparatus. A plurality of jet nozzles or propeller mixers is located in the storage tank within an annular band ranging between 25 percent and 75 percent of the radial length from a center of the tank to a tank wall. They are directed either in a tangent direction or at an angle away from the center of the tank to provide a substantially volume-filling mixing flow to suspend the solid slurry component in the liquid slurry component.

Abstract: An auger-tube pump mixing device for mixing materials with large density differences while maintaining low stirring RPM and low power consumption. The mixing device minimizes the formation of vortexes and minimizes the incorporation of small bubbles in the liquid during mixing. By avoiding the creation of a vortex the device provides efficient stirring of full containers without spillage over the edge. Also, the device solves the problem of effective mixing in vessels where the liquid height is large compared to the diameter. Because of the gentle stirring or mixing by the device, it has application for biomedical uses where cell damage is to be avoided.

Abstract: An apparatus has the capacity to satisfactorily blend a liquid with a powder and pump the resultant viscous slurry in a single stage operation. The apparatus has a vertically oriented drive shaft with a bladed impeller attached to the drive shaft. A housing surrounds a mixing chamber in which the impeller is located. The lower end of a powder inlet tube is disposed in very close proximity to the highest vertical extent of the impeller blades. A liquid enters the mixing chamber exterior of the powder inlet tube. The resultant slurry leaves the mixing chamber via a slurry discharge port.

Abstract: A device for preparing liquid to thin pulpy media having an inner chamber 1 is substantially symmetrical about longitudinal axis, and the inner chamber has a neck end and a passage end. An outer circumference of the inner chamber tapers down from the passage and to the neck end. An outer chamber surrounds the inner chamber, and the outer chamber is also substantially symmetrical about the longitudinal axis. The outer chamber communicates with the inner chamber through an opening in the neck of the inner chamber, and an opening in the passage end of the inner chamber. A centrifuge wheel is positioned inside the outer chamber and outside the inner chamber. The centrifuge wheel has an intake pipe extending from a center of the centrifuge wheel, and this intake pipe extends into the neck opening of the inner chamber. The centrifuge wheel and the intake pipe are substantially symmetrical with, and rotate about the longitudinal axis.

Abstract: A method for treating liquid waste water sludge after its generation and separation from the waste liquid involves forcibly impacting sludge particles and microbial cells against a contact surface to thereby fragment the particles into smaller-sized particles and break apart the organic cells. As a result of such a fragmentation process, water located in the pores of the sludge particles is released, thereby enhancing a subsequent dewatering process performed on the sludge. The destruction of the cells permits a subsequent solids digestion process to work more efficiently, while also permitting a more complete conversion to dissolved sugars, proteins and carbon dioxide.

Abstract: A method and apparatus for fragmenting waste water sludge particles to destroy sludge particles and to enhance a dewatering process performed on the sludge. Sludge is passed through a slotted rotor that centrifugally propels the sludge through slots in a surrounding annular stator. Sludge particles forcibly impact against the side surfaces of the stator slots to fragment into smaller sized particles. During the fragmentation process water located in the pores of the sludge particles is released. The free water can later be separated from the sludge in a dewatering apparatus. When passing through the rotor and stator slots, organic cells are broken apart and a portion of each is converted to dissolved sugars and proteins.

Abstract: The invention relates to a method for mixing liquids into each other or different phases into liquid by employing a double loop circulation, created below the surface zone of a reactor, in order to maintain an intensive mixing. It is characteristic of this Bottom Toroidal Roll or BTR principle that the employed mixer has a strong bottom draft and presses obliquely downwards, and that the mixer is installed according to the mixing method of this invention and that the flow pattern thereof is controlled in an exactly determined fashion. In our method the mixer jet hits the cylinder surface of the reactor, so that the jet is divided into two roughly equal parts by adjusting this distribution by means of a back-flow guiding member of the invention, which guiding member is located above the mixer. The rolling motion taking place in the reactor is controlled by means of specific baffles.

Abstract: The turbine agitator assembly including a reservoir for liquid, a rotor mounted in the reservoir and with a plurality of radially extending blades, and sparger means for introducing a fluid into liquid in the reservoir. The fluid sparger means and the rotor are so constructed and arranged that, in use, the rotor blades (submerged in the liquid) and/or the liquid flow they generate disperse the sparged fluid. Each of the blades is hollow and has a discontinuous leading edge, only a single trailing edge along an acute angle, no external concave surface and an open radially outer end.

Abstract: A mixer is disclosed for absorbing and mixing gases in liquids, or for mixing a liquid with another liquid and/or atomizing a liquid in a gas. The mixer includes an impeller with blades which are bent backward, the blades being surrounded on both sides by a front wall comprising an exhaust opening and a back wall sealing off at least the entire conveying area. A sectional chamber, which is built together with the coaxial hollow main shaft stub, is constructed in the shaft of the impeller and at least two blades are assembled with a pipe for propellant. The inner end of the pipe adjoins a sectional chamber and a nozzle is provided on the outer end. The impeller is closed off with a casing, injectors coaxial with primary nozzles are led through a casing, a mixing nozzle of the injectors is attached on three sides to the casing of the impeller, the front wall and the back wall while connected with a blade on the fourth side.

Abstract: The driving shaft (3) of a pump impeller (4) is extended beyond the impeller and supports the mixer (5) at its end. In order to minimize the risk for extensive damage if the mixer should hit a solid body, the shaft (6) of the mixer is very slim and manufactured of an elastic material such as spring steel.

Abstract: The invention relates to a method for mixing liquids into each other or different phases into liquid by employing a double loop circulation, created below the surface zone of a reactor. In order to maintain an intensive mixing, it is characteristic of this Bottom Toroidal Roll or BTR principle that the employed mixer has a strong bottom draft and presses obliquely downward, and that the mixer is installed according to the mixing method of this invention and that the flow pattern thereof is controlled in an exactly determined fashion. In our method the mixer jet hits the cylinder surface of the reactor, so that the jet is divided into two roughly equal parts by adjusting this distribution by means of a back-flow guiding member of the invention, which guiding member is located above the mixer. The rolling motion taking place in the reactor is controlled by means of specific baffles.

Abstract: A mixing apparatus is provided for mixing slurries, particularly high density, high viscosity fracturing fluid slurries containing a large proportion of proppant material. A mixing tub has a generally round horizontal cross-sectional shape. A relatively large, low-speed rotating agitator is utilized to mix the slurry. The design of the agitator is such that a radially inwardly rolling toroidal shaped slurry flow zone is created adjacent the upper surface of the slurry within the tub. A stream of clean fracturing fluid is introduced into the tub near the center of the toroidal shaped flow zone. Dry proppant material is introduced into the tube and carried by the radially inwardly rolling flow into contact with the clean fracturing fluid. Foraminous baffles, preferably constructed from expanded metal sheets, are radially oriented within the tub to reduce rotational motion of the slurry within the tub without causing dropout of proppant from the slurry.