Abstract: A cyclone comprising a swirl cylinder, an inner tube disposed in the upper section of the swirl cylinder, an inlet duct arranged tangentially to the outer periphery of the swirl cylinder, a drop opening formed in the lower section of the swirl cylinder, and a straightening instrument disposed in a space directly below the inner tube. The straightening instrument includes a conical member coaxial with the inner tube and guide plates arranged along a conical surface at the outer periphery of the conical member. A lower section of each of the guide plates is curved to encounter the turn tangential velocity components of a circumferential spiral stream smoothly into axial velocities alone, and unnecessary vortices which are not required for separation of particles and which cause energy loss are eliminated.

Abstract: A method and apparatus are disclosed for separating debris from a material product by recirculating the product in a product chamber with a fluid flow and using the fluid flow to entrain and remove debris.

Abstract: A fan impeller comprises a back plate, a front plate and a plurality of blades lying between the front and back plates, wherein the blades are fitted relative to the axis of rotation of the impeller to provide a leading edge adjacent the back plate, so as to impart, in use, a lateral sideways vector to a stream of and passing along the blades. At least two of the blades may be of increased thickness than the remaining blades. These improvements increase the life of the fan impeller significantly.

Abstract: The application disclosed a granular material classifying device comprising a horizontally disposed, transversely unrestricted wind tunnel, having an upstream end, a downstream end, a top end and a bottom end, for directing a horizontal airflow from the upstream end to the downstream end thereof; an air forcing assembly operatively mounted on the wind tunnel for inducing the horizontal airflow therethrough; a particle injection assembly operatively associated with the wind tunnel for free fallingly injecting a flow of granular particles to be classified into the horizontal airflow at an upstream, top end portion of the wind tunnel; and a bottom skirt assembly mounted at a bottom portion of the wind tunnel; the bottom skirt assembly defining at least one transversely unrestricted skirt cavity in fluid communication with the wind tunnel and having a downwardly and inwardly tapering cross sectional configuration adapted to provide a low velocity airflow interface between the wind tunnel horizontal airflow and th

Abstract: A portable hull separator includes a closed housing defining a pair of apertures which support removable drawers together with a plurality of air apertures. An air flow chamber within the housing is subjected to an air flow created by a motor driven fan. A seed bin within the housing is coupled to a descending air passage such that seed and hull material within the bin is caused to flow downwardly through the passage in which it is subjected to a transverse air flow. Adjustable gates are provided which alter the air flow characteristics and thereby the hull separation characteristics of the separator in accordance with an external adjustment.

Abstract: An elongated, horizontal and at least partially closed air jet dispersion and air jet entrained material deceleration zone is provided and one end of the zone includes at least skewed velocity distribution nozzle of the circular Coanda surface-type opening inwardly along the zone toward the other end thereof. The zone includes discharge structure defining a plurality of downwardly opening gravity-type outlets spaced longitudinally along the zone and duct structure for flowing air and airflow entrained solids therethrough at high velocity is provided. The duct structure includes an outlet end opening into the nozzle and an inlet end open to the ambient atmosphere and positioned to receive gravity discharged solid materials from the outlet spaced one outlet from the aforementioned one end of the zone.

Abstract: The zigzag classifier has a classifying space provided with air inlets which is subdivided into zigzag-shaped ducts, which are connected in parallel with respect to the flow, the lengths of which are greater than their widths. In this way a classifier package is formed with a plurality of small duct cross-sections. This design principle permits substantially lower overall heights for the same number of bends.

Abstract: In a classifier having a rotary classifying impeller in a casing for discharging fine powder to the outside of the casing, a leakage prevention apparatus is provided for the classifier which has a rotary seal member mounted on the upper plate of the rotary classifying impeller at the boundary portion between the rotary classifying impeller and a fine powder discharge duct. The upper portion of the rotary seal member protrudes outwardly from an opening in the top plate of the casing to separate the reduced air pressure in the discharge duct perfectly from the high pressure in the raw material dispersion chamber which is radially outside of the seal member. Furthermore, the rotary seal member can be provided with a circular groove in a J-shaped sectional structure. The end portion of this rotary seal member can also be formed into a square shape, a rounded shape or an inclined acute shape.

Abstract: Intermixed light leaf and heavy stem tobacco particles are fed or propelled inwardly and across a vertical separator chamber of the classifier while forced air is directed upwardly through the intermixed particles and at varying velocities across the length of the separator chamber to gently separate the leaf particles from the heavier stem particles. The stream of intermixed particles is projected across the separator chamber at a variable initial velocity and the varying velocities of the upwardly directed forced air streams are correlated with the velocity of the stream of particles being fed across the separator chamber to gently separate the light leaf particles from the heavier stem particles. An adjustable deflector plate is supported adjacent the inlet feed for varying the angular position of the feeding of the stream of intermixed particles across the separator chamber to thereby vary the classifying plane in which the particles are projected across the separator chamber.

Abstract: In a cyclone classifier wherein the material to be processed is swirled in a tubular casing having a conical lower portion and classified, a cylindrical body is provided in the casing, so as to surround the lower end of a fluid outlet pipe and extends downwardly below an inlet port for the material to be processed, so that the sectional area of passage for the material to be processed swirled in the casing will be made smaller, thus increasing the classifying point while keeping the pressure loss at a minimum. From another aspect, annular pipes formed with fluid inlet ports are provided around the outer periphery of a lower part of the casing so as to communicate with the casing so that gases or liquids will be blown into the lower part of the casing through these pipes to form a swirling current, thus allowing the material to be processed to be reclassified thereby increasing the classifying point.

Abstract: Apparatus for separating heavy from light constituents in coarse comminuted municipal waste having a relatively small inlet duct connecting to a much larger air classifying chamber. A by-pass duct is disposed alongside the chamber, and connects thereto at its upstream and at its downstream end. Dameprs are provided to adjust the velocity of airflow through the chamber and by-pass duct depending upon the density of the light weight constituents.

Abstract: A blender for solid particulate material such as plastic pellets which includes an apparatus for separating a fine fraction of material from the plastic pellets. This is accomplished by a separator shell which surrounds a vertical lift pipe in the blender. Gas under pressure is utilized to circulate material through the lift pipe from the bottom of the vessel to the top of the vessel to blend the material. As material is discharged from the vertical lift pipe, the air supplied through the lift pipe for lifting material flows through material dispersed within the separation zone to entrain the fine material and convey it through a vent to a high efficiency dust collector. A by-pass conduit and by-pass control valve are provided to control the velocity of gas through the separation zone to control the size particle of the fine fraction which is separated.

Abstract: In a classifier including a rotary disc provided on a lower end of a vertical rotary shaft depending from the top of a hopper-type casing, a horizontal dispersing disc is provided directly below the top of the casing, a circular collision plate is spaced from the outer circumference of the horizontal dispersing disc, and a plurality of vortex adjusting members are secured at their upper ends to the horizontal dispersing disc and at their lower ends to the rotary disc, and a leakage prevention apparatus is provided which comprises a plurality of dispersing and classifying vanes spaced from the outside of the vortex adjusting members and the inner sides of the collision plate. The dispersing and classifying vanes depend from the under surface of the horizontal dispersing disc for an appropriate length.

Abstract: In the case of an apparatus for cleaning grits, which has a plurality of superimposed screen layers, which can be vibrated by means of at least one unbalance exciter and with an inlet or outlet for the product inlet or screen discharge arranged at one end, collecting means with adjustable setting flaps for the screenings, as well as an air circulation through the screen layers over an air distribution chamber in a suction collecting channel adjustable by means of adjusting flaps, it is provided that the apparatus is constructed as a stand with a stand head, a stand base and a vertical intermediate support connecting said two parts, the screen layers being constructed as a dust box and being vibratably supported in the vicinity of the stand base, the stand top being formed by the upper air distribution chamber.

Abstract: A process for classifying toner particles supplied through a supply nozzle into at least three fractions in a classifying chamber divided into at least three sections and placed under a reduced pressure under the action of the inertia force of the toner particles supplied together with a gas stream and the centrifugal force of the curved gas stream due to Coanda effect. A first gas introduction pipe and a second gas introduction pipe are disposed above the classifying chamber so as to provide a first inlet and a second inlet opening with the first inlet being disposed closer to the supply nozzle than the second inlet. The absolute values of the static pressures P.sub.1 and P.sub.2 in the first and second gas introduction pipes are controlled so as to satisfy the relations of: .vertline.P.sub.1 .vertline..gtoreq.150 mm.aq., .vertline.P.sub.2 .vertline..gtoreq.40 mm.aq. and .vertline.P.sub.1 .vertline.-.vertline.P.sub.2 .vertline..gtoreq.100 mm.aq.

Abstract: The invention relates to an apparatus for classifying powdered bulk materials, particularly ground clinker, limestone or cement raw material, by air sifting. The material to be classified is fed to the cover plate of a cylindrical rotor and charged into a sifting space having the shape of a cylindrical ring which extends between the rotor and a stationary vane ring which is spaced from and surrounds the rotor. While the coarse material descends in the sifting space, the fine material is conveyed into the inside of the rotor and fed to a subsequent separating device for the separating of fine material and sifting air. In order to simplify the construction and stocking, both the rotor and the housing surrounding it are assembled in building-block fashion from a plurality of identical sections, at least one tangential air inlet connection being associated with each housing section. Each housing section can have associated with it at least one cyclone of its own with its own fan.

Abstract: The invention relates to a sifter in which the spiral for delivery of the air for sifting is divided into a plurality of channels lying one above another in which elements for setting the quantity of sifting air delivered to the individual channels are provided. In such a sifter the quantity of sifting air in the individual regions of the sifting chamber can be optimally adapted to the requirements, which leads to a substantial improvement in the degree of separation.

Abstract: A particle classifier and in particular a particle classifier wheel where the blades are made entirely of a wear-resistant material such as sintered corundum. The blades extend between two discs and are mounted therebetween to have some axial play. The ends of the blades fit into annular grooves formed in the two discs and rubbery-elastic inserts are provided to hold the blades in place.

Abstract: The invention concerns a pneumatic classifying procedure and apparatus for dividing particulate material into a fine product consisting of lighter particles and a coarse product consisting of heavier particles. The classification takes place in a cylindrical classifying space (1) in which can be established a centrifugal field with the aid of tangential supply of the material to be classified or with the aid of a mechanical rotor, the field separating the fine product into the center of the classifying space and the coarse product to its outer margin. It is essential in the invention that the coarse product is removed with the aid of a separate gas flow which is tangential to the centrifugal field. The gas flow runs in a passage (11) which is tangential to the classifying space (1) at the site of the coarse product removal aperture (9).

Abstract: Waste material classifying apparatus for applying forced air streams to the waste material discharged off the end of a rotary disc screen conveyor, directing the forced air streams into an enclosure at the discharge end of the conveyor, and forming separate passages in the enclosure so that the waste material fractions are classified by the response of the fractions to the forced air or lack of response to forced air streams, whereby the forced air streams tumble and flip the waste material for augmenting the separation of the fractions.

Abstract: A method and mechanism for the separation of materials from a stream of pulverulent material such as cement including a rotatable plate onto which the material is fed with the material being centrifugally discharged in a bell shaped flow pattern, a radially inwardly directed flow of air across the veil carrying fine materials inwardly through a rotatable distributor; and coaxial dip tubes centrally located for receiving the gradations of fine material passing gravitationally downwardly, with the coarse materials remaining outside of the distributor and being received in a downward flow.

Abstract: An elutriator (1) for separating different grades of leaf vegetable material comprises an elutriation zone (17) disposed above a flow distributor, and gaseous supply means (13) for supplying a gaseous medium to the elutriation zone (17) through the flow distributor. The flow distributor is adapted to provide a substantially uniform flow of gaseous medium to the elutriation zone (17), and the velocity of air delivered to the zone is greater than the terminal velocity of at least one grade of the material to be separated.

Abstract: In separating pecan meats according to weight, removal of acceptable pecans along with lighter, unacceptable pecans is obviated by avoiding the increased vacuum on acceptable pecans which occurs when an unacceptable pecan restricts a vacuum duct used for such separation. In one embodiment, positive and negative fluid pressures are utilized in concert to avoid such a restriction.

Abstract: A pneumatic separator for separating lighter particles from heavier stem particles and the like, as in tobacco threshing, including a separating chamber having air circulating in a generally upward path therethrough, an inlet rotary impeller mounted on one side of the separating chamber for thrusting particles to be separated into and across the chamber toward a generally upwardly extending opposite wall of the chamber, an inclined perforated plate member below the level of the impeller for directing larger particles discharged toward or falling onto the inclined plate member for collecting and carrying heavier particles from the chamber, and an air jet impeller located immediately above the inclined plate to discharge an air jet therefrom for directing material into a high arc trajectory into the chamber.

Abstract: Apparatus for separating relatively large particles from dust particles, comprising an enclosed separating station for separating the large particles from the dust particles. The large particle and dust particle mixture is pneumatically conveyed from a supply source to the separating station. The separated large particles and dust particles are conveyed from the separating station to respective depositories by respective pneumatic conveyors.

Abstract: The invention relates to a sifter having a dispersing plate which has material passage openings therein. The dispersing plate carries guide elements and distributor elements adjacent such openings which are inclined with respect to the radius of the plate. Such a dispersing plate makes it possible to feed the material to be sifted into the sifting chamber very evenly.

Abstract: A separator for sorting particulate material has a rotor (1) with vanes (3); static, separately adjustable guide vanes (8,9); a casing (14) defining an inlet duct for material suspended in a conveying gas; an outlet (7) for a suspended fine fraction; and a hopper (12) for collecting a coarse fraction.

Abstract: The separator device comprises a vertical, cylindrical container (4), provided at the bottom with a rotary discharge valve (9) and provided with a duct (5) which opens into its top portion and is connected to the feeding source of the meal. This duct (5) discharges the meal onto the top of a conical downwardly diverging tray (1) arranged in the container (4), and arranged at a suitable distance below said tray (1) is another conical member (6) also diverging downwardly and provided with an upwardly directed peripheral edge (106) extending beyond the peripheral outline of the tray, and closely spaced from the side surface of the cylindrical container. At the top of the conical member (6) is an opening (10) which is connected to a conduit (11) extending through the wall of the container (4) and connected to a suction source. Inside the container (4) below the conical members (1, 6), there opens a conduit (15) communicating with the atmosphere.

Abstract: The invention relates to a rotary basket air classifier. A favorable predispersion of the material to be classified, particularly in the case of an upwardly directed spent classifying air line has always been problemmatical with such classifiers. According to the invention, the material to be classified is distributed over several stages, aided by dispersing blades and a higher drawing-off capacity of the spent classifying air is permitted by the branching of the drawing-off line.

Abstract: A particle classifier has a uniform, laminar, classifying air stream and a duct to introduce particulate material generally perpendicular to the air stream. The particulate material is entrained in a secondary air stream that is diverted as it enters the classifying air stream by a curved surface. The curved surface produces and diverts the air stream by the Coanda effect to minimize disturbance to the classifying air and segregate the particles from the secondary air.

Abstract: Centrifugal air classifiers without rotating classifying blades are frequently used in present-day coal-fired power stations. For economical reasons, these obtain the coal to be burnt from different sources so that the pulverized-coal furnaces are operated with coals of varying quality. In this arrangement, it is disadvantageous that, when coals of particularly low quality are burnt, this classifier is not capable of supplying the fineness of pulverized coal required for proper combustion. The invention has the object of creating a centrifugal air classifier of the type initially mentioned which provides the possibility of proper combustion of several types of coal in a pulverized-coal furnace.

Abstract: An arrangement in machines for separating materials having different aerodynamic properties and employing an air current for actuating the materials.A sensor is located in the path of particles carried along by the air current, to generate electric signals in dependence on particles impinging the sensor. The sensor is operatively connected to a control for regulating the flow rate of the air current in order to obtain an air flow corresponding to a predetermined impingement intensity.

Abstract: A cyclone separator for the separation of lighter material (i.e. discontinuous or dispersed phase) can cope with fluctuating proportions of lighter material in the feed stream.A retractable plug 15 at the place where the cyclone overflow outlet meets the cyclone body has a bore 16 forming the effective overflow outlet. The plug is retracted while the cyclone separator is in operation, in response to sensors, to offer a larger outlet 12 as the need arises.

Abstract: A separator for sorting particulate material suspended in a conveying gas into coarse and fine fractions has a rotor (1) with two sets (9,10) of vanes. Dampers (13,14) in outlet ducts for the fine fraction regulate the relative flow through the two vane sets and hence control the cut between the fine fraction and the coarse fraction which is flung centrifugally outwards by the vanes and falls down inside a casing (3).

Abstract: A tobacco separator is provided for separating light fractions (laminae) from heavy fractions (mid-rib or stem) from threshed tobacco.The separator comprises a separating chamber (10) having an upper first inlet (8) for receiving the material to be separated or classified, and a lower second inlet (9) for receiving a flow of air directed transversely of the material path from the first inlet, a plurality of channels (14-17) are disposed one above the other to receive the tobacco laden air from said inlet, a vertical air passage (20) in communication at its lower end with the lowermost of said channels; and an outlet passage (19) in communication with all said channels.

Abstract: Apparatus and method for removing dust from particulate material, utilizing a tower or column having a passage with a series of baffles on opposite sides over which the particulate material cascades while air is drawn across the flow path of the material to remove the dust dispersed in the material and adhering to the surface of the particles of material. Air is drawn across the passage from one side to the other by vacuum or suction from a vacuum pump or the like. In performing the method using the apparatus, the particulate material is introduced at the top of the column and permitted to cascade down through the vertical passage therein from one baffle to the next, and air is drawn inwardly between the baffles on one side and outwardly between the baffles on the opposite side of the column, and, as the air flows through the material cascading between the baffles, it removes the dust from the material.

Abstract: A seed treating machine for the separation of seeds from lighter-weight particulant plant matter intermixed with the seeds. The seed separating machine includes a horizontally mounted table having a center opening under which a plurality of fans are mounted to provide an upward blast of air. A screen is affixed to the table over the center opening and a harvested mixture such as seeds and particulant plant matter are placed on top of the screen. The blast of air lifts the lighter particulant matter away from the heavier-weight seeds. A semicircular cover is affixed to the table covering the screen to contain the seeds. The lighter-weight material is released to the atmosphere. The table is pivotally mounted upon an upright stand, permitting the table to be tilted from side-to-side to fully expose the mixture to the air blast. The separated seeds roll down the table through a chute and into a container for packaging.

Abstract: An air separator method and apparatus provides a second, preferably downward air stream about and rotating in the same sense as a first, upward air stream to carry away coarser feedstock material siezed from a supply and centrifugally separated from finer feedstock material by the first air stream.

Abstract: The invention comprises a sinter belt and a collector, vacuum chambers, a gas cleaning device, an air purifying device, and an exhauster mounted adjacent the belt. Above the sinter belt are mounted assemblies for loading a bed and a charge, and an ignition hearth. Downstream from the sinter belt are mounted a sinter breaker and an inclined chute wherein are mounted vibrating screens communicating with a cooler for a sinter return and for the bed, and an air classifier. The air classifier comprises a fan, a diffuser, a movable grid for varying the speed of the air produced by the fan, and a partition member forming a settling chamber together with the chute. Within the settling chamber is mounted a device for settling coarse fines, said device communicating with the collector through the air purifying device, and with the cooler for the sinter return.

Abstract: An adjustable classifier for the separation of fluid-suspended solid particles in industrial processes and by which the relative proportion of acceptably fine and unacceptably coarse solid particles may be regulated. Adjustability is achieved in an otherwise static classifier structure in which a fluid stream of multi-sized particles is passed through a curved path, by the provision of interleaved fingers movable from a retracted inactive position against an outer boundary surface defining the curved path to an extended position into the stream to re-entrain all particles moved against the outer boundary surface back into the fluid stream. Fine particles so re-entrained will pass from the classifier and relatively coarse particles will be rejected by centrifugal action. The invention also contemplates an adjustable plate member by which the velocity of the fluid stream may be regulated independently of the aforementioned fingers.

Abstract: An apparatus for separating a desired, relatively light fibrous fraction from admixture with foreign bodies, such as sheaths, metal parts, plastic parts and the like and having parts, such as stems, rind remnants, leaf parts and the like. The apparatus comprises structure which causes separation by gravity and which conveys the mixture past a separation location and floats the relatively light fibrous fraction from the mixture in an upwardly directed air stream.

Abstract: An improved apparatus for extracting a side-stream flow of fine-particulate-laden effluent gases from a mechanical separator employs the use of a plenum inside the housing of the separator with a plurality of pickup openings communicating the plenum with spaces among and about the separator's collector tubes. A side-stream flow of fine-particulate-laden effluent gases is extracted from regions among and about the collector tubes by drawing these gases through the pickup openings and into the plenum, from the plenum into a ductwork communicating with the plenum, and from the ductwork through a separator where particulate matter is filtered from the side-stream flow. The method of constructing the apparatus is also disclosed.

Abstract: Apparatus and system for carrying out the air separation of waste wherein the waste is transported by conveyor to the input location of the housing of the apparatus, whereupon it is dropped. A fan having a selectively directed dual airstream is positioned to provide airstream interception of the material stream falling to a confrontation region. Baffling is provided to substantially eliminate turbulence as may be caused by the fan. Separation is developed at three outlets beneath a plenum of the apparatus and a deflector is positioned between that outet receiving organic and that outlet receiving plastic categorized materials. To improve separation, deflectors are mounted vertically on the housing walls to increase airstream velocity. Airstream guidance, deflection and baffling are made adjustable to tune the system to accommodate for variations in the consistency of waste.

Abstract: An apparatus for separating debris from spent abrasive in an abrasive blasting apparatus in which the debris and spent abrasive are recirculated from a blast zone at high velocity along a recirculation chamber includes means for receiving debris and spent abrasive from the recirculation chamber and allowing a quantity of the debris and spent abrasive to collect thereby forming a pile having a face exposed to incoming debris and spent abrasive. The pile has an angle of repose, whereby additional incoming debris and sent abrasive fall down the face to form a substantially unobstructed, vertical, uniform curtain of falling debris and spent abrasive. Means for providing a stream of fluid through the recirculation chamber are provided. Means having first and second openings are provided for drawing off the stream of fluid, which is divided into portions, from the recirculation chamber.

Abstract: A grain cleaning device is provided which separates foreign material from grain by aspiration. The aspiration force is developed by a fan which is attached to the grain cleaning device. The device includes a housing, a grain inlet in said housing, a louvered grain slide located within said housing, an opening within the housing which is compatible with the fan, air intake holes within the housing and adjustable covers for said air intake holes. The grain enters the grain cleaning device through the grain inlet and travels down the louvered grain slide. The fan which is located above the louvered grain slide acts as an aspirator and removes the foreign material from the grain which has a density less than the density of the grain. The foreign materials are drawn up through the fan and out an exhaust vent. The housing includes a grain slide housing and a chimney, the chimney being attached to the top of the grain slide housing.

Abstract: An apparatus for separating debris from spent abrasive in an abrasive blasting apparatus in which the debris and spent abrasive are recirculated from a blast zone at high velocity along a recirculating chamber includes means for receiving debris and spent abrasive from the recirculating chamber and allowing a quantity of the debris and spent abrasive to collect thereby forming a pile of debris and spent abrasive with a face of the pile exposed to incoming debris and spent abrasive. The pile has an angle of repose whereby additional incoming debris and spent abrasive fall down the face to form a substantially unobstructed, vertical, uniform curtain of falling debris and spent abrasive. The apparatus includes means for providing a stream of fluid through the recirculating chamber, and means disposed below the receiving means for drawing off the stream of fluid from the recirculating chamber.

Abstract: A method and apparatus for classifying desirable particles of powder metal by size and removing particles of undesirable material of a different density than the metal particles. There is included a housing defining a closed flow path for a recirculated stream of protective gas different than ambient air. A particle supply device introduces particles into the housing at a controlled rate in a downwardly falling stream. A plurality of receptacle trays are disposed in the housing generally vertically below the particle supply device with each tray having a forward lip positioned forwardly in the direction of the gas flow of the trays thereabove.

Abstract: A separator for a pneumatic conveyor system having fixed wall and a movable wall jointly defining a chamber of greater crossection than a conduit supplying a particulate carrying airflow. An inlet discharges the airflow into the chamber and into impingement with the movable wall to initiate particle separation.

Abstract: A classifying system including an air elutriation device is disclosed, which device is in the form of an upright box defining an airflow chamber open at its lower end and connected at its upper end to an exhauster device. A mixture of particulate materials is admitted into the chamber through a slot in the side of the box above a series of rods which extend across the chamber and are adjustable for varying the rate and turbulence of the airflow in the admitting zone to separate the lighter particles from the heavier particles in the mixture with the lighter particles being carried by the airflow upwardly and out of the chamber.

Abstract: An air classifier comprises a casing formed of a generally hollow cylindrical vertical casing body and an inverted conical hopper fixed to the lower wall of the casing body. A fine product outlet duct is provided at the center of the upper wall of the casing body. An air-powdered material inlet duct and a secondary air inlet duct are set in the diametrically opposite positions of the vertical wall of the casing body to project tangentially outward. A vertical rotary shaft extends through the central portion of the casing body. A rotary disc member for concurrently carrying out the dispersion and classification of a powder raw material is fitted to the lower end of the rotary shaft at a boundary between the casing body and hopper. A cage-shaped assembly of guide vanes is provided in the casing body to conduct a mixture of air and powdered material into the casing body.