Abstract: A grinding apparatus includes a roller mill in which material particles are pre-ground, a tube mill connected to the roller mill through a fluidized-bed-type classifying device in which the material particles are classified by size and a circulation line is connected between the classifying device and the roller mill, wherein a fluidized portion of the pre-ground particles, which consists of a fine material component is fed into a tube mill, a remaining portion of the pre-ground particles, which consists of course material and some amount of fine material not fed into the tube mill is returned to the roller mill through the circulation line where the remaining portion of the pre-ground particles is again crushed together with newly fed material particles in the roller mill.

Abstract: A two stage hammer mill which reduces recycled glass and its associated contaminants to small glass particles in the 100-800 grit size range and waste. The glass grinder is of light weight, modular construction, such that it may be taken apart, relocated, and restored to operation quickly and easily. A modular design also allows it to be easily cleaned and reconfigured to produce aggregate of selectable size. Located on separate rotors, installed in separate grinding chambers, the two hammer mills are spaced apart from one another and mounted within a common housing. The first stage provides a relatively coarse reduction of the material flow, which then passes into the secondary grinding chamber where the material is further ground. The design of the hammers in this hammer mill are such that they entrain a large quantity of air, accelerate it to high velocity, and drive the mixture of air and material through the system, entraining small, medium and large sized particles.

Abstract: To improve the operation of a roller press, a method is described according to which fluidized material that is discharged from the roller press over and above the sides of the roller press is collected and passed on to the next process stage together with the material which is ground in the roller press and discharged from the centermost section of the roller press. The remaining material which was ground in the roller press and discharged from the roller press through its end sections is returned to the roller press.By practicing the method of the present invention, a depletion of the material in the feed shaft is prevented due to a more stable roller feed, hence obtaining a smooth operation, even for high circulation factors, a higher average power absorption and a higher output level.

Abstract: A new and improved media granulation apparatus includes a cyclone chamber assembly which includes an outer wall, a plurality of vortex controller assemblies connected to the outer wall, and an inner wall. A first conduit is connected to the inlet of the cyclone chamber assembly. A blower assembly is connected to the first conduit, for creating a cyclone flow within the cyclone chamber assembly, and a media feed assembly is connected to the first conduit for supplying media to be ground to the cyclone chamber assembly. The respective vortex controller assemblies include a vortex control element which is substantially cylindrical, e.g. D-shaped, in cross-section and a pivot for connecting one end of the vortex control element to the outer wall. A slot-riding connector is connected to the vortex control element for riding in an arced slot in the outer wall.

Abstract: An energy-saving effective sifter used in interparticle crushing of brittle charging stock such as cement clinker in the nip of a high pressure roller press including a dynamic sifter having a rotating rod basket and laterally preceding the rotary rod basket sifter by a fluidized bed pre-sifting chamber having an admission opening at the top with a chamber defined between opposed porous walls to provide a pre-sifting zone with the walls formed by angularly adjustable baffles in one form, and passing air across the zone toward the rotary rod basket, removing a coarse grain fraction below the pre-sifting chamber, removing a medium grain fraction from beneath the rotary rod basket and removing fine material axially of the rotary rod basket passing the medium grain and coarse grain fraction into an interparticle crushing high pressure roller press having a nip pressure in excess of 2 t/cm of roller length, mixing the medium grain fraction and coarse grain fraction with a pre-comminuted pulverulent material such a

Abstract: An improved coal pulverizer classifying system in which the feedpipe and classifier cone are provided with extensions to protect coal flow into the pulverizer from the annular fine-lifting airflow from the pulverizer throat. The feedpipe and cone extensions replace traditional intermittent discharge structure, improving flow through the classifier system and reducing the disruptive effects of the discharge on the annular flow from the pulverizer throat. An adjustable classifier venturi is also provided to adjust the exit angle and exit velocity of the fines leaving the classifier cone by the combustion delivery chute.

Abstract: Fresh raw material is delivered to a crushing zone for crushing. Beforehand, fine particles are separated from the raw material by means of an airstream and directed into the housing of the crusher where they are entrained by an independent gas stream that conveys crushed fines upwardly to a separator also located within the housing. The separator removes fine particles from the system and returns the remaining, relatively course tailings material to the crushing zone through a tailings return chute. At least a portion of the material exiting the tailings return chute is subjected to a secondary separation treatment to capture additional quantities of fine particles before entering the crushing zone. The captured tailings material may be mixed with the fresh raw material else reintroduced into the top of the separator to receive the secondary separation treatment.

Abstract: The invention relates to the comminution of material for grinding, particularly for the production of cement, wherein the material for grinding is comminuted in a mill and the comminution product is classified in a classification zone into fines and oversize material and the oversize material is returned to the mill. With a view to effective influencing of the breadth of the particle size distribution as well as a relatively low specific energy consumption the comminution product is classified in the classification zone in at least two air separators which are connected one behind the other in series, and a proportion of the oversize material from the first air separator is returned directly to the mill, the remaining proportion being delivered to the second air separator.

Abstract: An apparatus and process for screening a product grade of particulate matter from a feed-stream of particulate matter is provided. Specifically, the apparatus is a vibration screening action machine which vibrates, including motion having a component thereof perpendicular to the plane of the screen deck, at least one screen deck having a mesh defining the lower limit of the product grade. Such vibration screening action machine is optimized for ensuring the throughput of particulate fines through the mesh defining the lower limit of the product grade and thus substantially removing particulate fines from the product grade by setting the screen deck at a relatively low angle, as measured from horizontal, of less than 15 degrees.

Abstract: A system and apparatus for size reduction and classification of solids particles to aid in their disposal. The system includes mixing the solids particles in a viscous liquid to form a slurry in a receiving tank, passing the slurry through a series of initial screens and magnets, and circulating the slurry through a series of reduction tanks to a holding tank by vertical fluid mills. The vertical fluid mills include a slurry inlet and outlet and have a rotating shaft to which is mounted a series of rotating perforated disks which rotate in close proximity to and between a pair of stationary blades. The disks and blades are situated between series of impellers mounted on the rotating shaft. The reduction tanks include screens for solids classification and recirculation of the solids particles.

Abstract: A method of crushing brittle materials for obtaining a product of great fineness, wherein the raw material is fed to a roll mill providing a product containing agglomerates and carried into a disaggregator-separator, the fine particles being discharged and the coarse particles being recycled, the disaggregation rate being limited in the disaggregator and the invention being applicable to cement clinker and to various mineral substances.

Abstract: A material reducing mill having a construction which operates to create a circulation of material in the mill to effect a thorough reduction of material added to the material undergoing reduction. The mill is further constructed with a rotary device which is associated with an external collection system, which device constantly samples the circulation in the mill so as to withdraw that portion which can be fed into the collection system. Furthermore, the external collection system is provided with sensors which are adapted to regulate the circulation of the material intended to be reduced to micron size portions.

Abstract: An apparatus and method for reclaiming fiber reinforcement material from cured SMC waste products provides a series of roller mill pairs having a differential speed capacity between paired rollers. The rollers impart a shearing and crushing force to the material which breaks the bond between the reinforcement fiber filaments and the resin binder while preserving the structural integrity of the filaments.

Abstract: A paper material screening and refining apparatus has a tank which receives a paper material to allow the paper material to accumulate therein; a cylindrical screen which divides the space in the tank into a primary chamber and a secondary chamber; a cylindrical rotary member carried by a rotary shaft and disposed so as to oppose to the screen; a rotational member carried by the rotary shaft and disposed near the end of the tank remote from the paper material receiving end of the tank; a water supply pipe for supplying water into the primary chamber from the region near the rotational member; a water supply valve provided in the water supply pipe; a discharge pipe for discharging the paper material in the primary chamber of the tank from a region near the rotational member; and a discharge valve provided in the discharge pipe.

Abstract: Chocolate is ground in order to obtain a very small average particle size. A determined viscosity is necessary for further processing. In order to keep as small as possible the fraction with particle size lying above the desired value and having an adverse effect on the taste of the final product, according to the invention the process mass is circulated in a cycle incorporating a grinding device and a ball mill. This has the result of accelerating the grinding process and reducing the inconsistency in the distribution of the particle size.

Abstract: Apparatus for grinding material which comprises a flow of ground material that contains both desirable fines and undesirable oversize particles in which a separator rotor is equipped with shaped blades that isokinetically separate out the oversize particles and centrifuges such particles out of the path of the flow of ground material and into a path for returning the oversize particles for further grinding. The centrifuging of the oversize particles reduces the drag in the flow of the ground material into the separator rotor, and that reduces the horsepower needed to establish the movement of the ground material at a rate that improves the efficiency of the apparatus. A variation of the foregoing develops pressurization of the material in the separator zone so that the oversize ground material is forced to return to be subjected to further grinding under the influence of a differential pressure in the apparatus while the acceptable material is subject to micron sizing in the rotor.

Abstract: A device for crushing and screening bulk materials consists of a vertical impact mill with associated feeder, an air-charged separator, a discharge device for the final product and a conveyor for returning the insufficiently crushed bulk materials fraction to the crushing region. The vertical impact mill and the separator are arranged on a divided drive shaft, which can be coupled if necessary. The separator is arranged below the vertical impact mill and is designed as a distributor plate, possibly with guide blades. The air is introduced laterally or tangentially below the distributor plate. The finished materials fraction is discharged laterally or tangentially above the distributor plate and conveyed to separator (cyclone) which may be connected downstream. The insufficiently crushed bulk materials fractions are discharged through an outlet below the distributor plate in the base region of the separator.

Abstract: Raw coal is caused to fall through a coal feed pipe and onto a table so as to be pulverized by a roll. Fine coal particles and coarse coal particles resulting from pulverization are moved upward between an auxiliary classifier cone and a mill casing by hot air supplied from below the mill casing. The hot air (upward stream) carrying the fine coal particles and the coarse coal particles moves across a space of triangular cross section formed between the inverted conical body of the auxiliary classifier cone and the side wall of the mill casing and is forced through blowoff openings defined between deflector plates so as to flow as a lateral rotative stream toward a rotary classifier. Upon impinging the downward-inclined rotating vanes of the rotary classifier, the coarse coal particles are sprung back toward a lower portion of the auxiliary classifier cone and are separated from the fine coal particles.

Abstract: Apparatus for disposing of wet sludge by conversion to a substantially dry product during grinding of the wet sludge in a drying atmosphere which promotes the separation of the grindings into coarse fractions and fine fractions so that the coarse fractions in the dried condition can be directed to enter the supply of the wet sludge for reducing the moisture content to prepare the mix of wet sludge and coarse fractions for grinding in a drying heat atmosphere to perpetuate the supply of coarse fractions for moisture reduction of the wet sludge and a supply of the fine fractions as a product of the apparatus.

Abstract: Prior to entering a tumbling media mill grinding chamber, feed containing clumps of adherent fine and coarse particles is brought into jarring contact with a moving member for liberating fine particles. Liberated fines are contacted, outside the chamber, with a current of gas to remove them from the remainder of the feed. At least a portion of this remainder enters a bed of charge material in the chamber and is ground with the media. When an indicator of a developing or existing over-fed or under-fed condition in the bed is sensed, adjustment of the jarring intensity, of the gas velocity or of both is made in response to the indicator for increasing and decreasing the quantity of fine particles removed from the feed. A clump separator, having an enclosure, jarring member and coarse solids outlet, may be used to liberate fines. This outlet is connected with a coarse solids inlet to the chamber. A path other than the coarse solids outlet is provided for removing liberated fine particles from the enclosure.

Abstract: The apparatus and its process utilization enables a higher throughput of ore bodies being comminuted, provides a closer or more accurate selection of size of particles or particulates produced, has a low noise level in its operation, and uses its rotor impeller to facilitate the charging-in of ore bodies to be processed, the breaking-up of such bodies, and the delivery of such bodies in the form of sized particles or particulates is introduced by suction peripherally into one of the compartments of a motor-drive impeller and axially into all of the compartments, ore bodies are introduced into all of the compartments and are thrown under centrifugal force from one of the compartments against an anvil. Broken-up bodies of a desired size are fluidized and moved upwardly out of the apparatus while those of a rejected size are returned to the impeller for reprocessing with additional ore bodies being newly introduced therein.

Abstract: A process and device for crushing bulk materials. The material to be crushed is fed from above to a first accelerating device which accelerates it into a first crusher, the fine particles in the crushed material produced by the first crusher being carried upwards by an air or gas stream. The larger particles trickle downwards and are then carried by an air or gas stream vertically upwards to another accelerating device which accelerates them into another crusher. The fine particles produced in the second crusher are swept upwards by the air or gas stream, while the larger particles trickle downwards and are brought round to the beginning of the cycle again. The invention concerns the combination of a vertical impact crusher with a separator, both of which are preferably located inside the same housing.

Abstract: Scrap goods (S), for example, electronic and electrical apparatus, components, cables and the like are intermittently and alternately mechanically crushed (1,3), magnetically separated (2) and mechanically-physically separated, for example, by means of electrostatic separators (5, 10-12). With the crushing, the dust produced is pneumatically gathered and filtered out (22,9). A non-metal fraction (A) as well as a magnetic (B) and non-magnetic fraction (C) are produced separately as granules and dust. The metal fractions (B, C) are suitable for further pyrolysis-free, wet chemistry and/or electrolytic separation. The non-metallic fraction is capable of being precipitated. The method is noted for its minimal energy consumption and high environmental compatibility.

Abstract: A two-stage procedure is disclosed for sorting wood chips. The chips are directed to a gyratory screen in the first stage and to a disc screen in the second stage. The chip flow is divided in the first stage into four fractions of which the first fraction contains mainly oversized chips and is directed to a pin chipper, from which it emerges as suitable-sized chips and is directed back to the gyratory screen of the first stage. The second fraction contains acceptable sized chips and most of the overthick chips and is directed to the second or thickness screening stage. The third fraction consists mainly of acceptable chips and is directed to a pulping process, while the fourth fraction consists mainly of fine particles and is directed to a burning station.

Abstract: In autogenous grinding of mineral material in a grinding mill with a screening wall a method is provided for enabling the removal of at least three different fractions without the need of the screening wall being divided into sectors, thus increasing grinding material turnover and grinding capacity, by passing through openings (8) distributed over the screening wall (7) a mixed material fraction containing all material fractions having a maximum particle size less than or equal to the largest size opening for screening coarse material in the size intended for use as a grinding charge in a further mill (23) and dividing up the mixed material fraction into at least three fractions in a classifying apparatus (13), by always taking out from the classifying apparatus (13) at least a fine fraction, a coarse fraction and a medium coarse fraction, the latter two fractions being kept separate for permitting, as required, diversion (38) of the coarse material fraction as grinding charge to following grinding steps, the

Abstract: A grinding system for grinding brittle material such as used in the manufacture of cement including a high pressure roller press operated with high pressing forces to form interparticle crushing with incipient cracks in the interior of the particles including recirculating a portion of the material delivered from the press to a sifter locating the sifter directly above the nip and delivering the sifted material downwardly into the nip retaining the structural height of the system low and delivering fresh stock laterally directly into the nip of the roller press to merge with the sifted material entering directly into the nip of the roller press.

Abstract: A toner for developing an electrostatic latent image is produced by classifying a pulverized feed material in a first classifying means into coarse powder and fine powder; pulverizing the coarse powder and feeding back the pulverized product to the first classifying means; introducing the fine powder to a second classifying means having a multi-division classification zone divided into at least three sections, where it is classified into a coarse powder portion, a median powder portion, and a fine powder portion; and feeding back the coarse powder to said pulverizing means or first classifying means. The median powder has a volume average particle diameter of from 4 .mu.m to 10 .mu.m and a coefficient of variation of number distribution, represented by A, satisfying the following condition: 20.ltoreq.A.ltoreq.45, and the weights B, C, F, G and M are controlled to satisfy the expressions: 0.3 .ltoreq.weight B/weight C.ltoreq.0.8, 0.2.ltoreq.weight G/weight C.ltoreq.0.7 and 0.8.ltoreq.

Abstract: The invention relates to a method and a grinding plant for reduction of brittle material for grinding, in which material which has undergone primary reduction from a first grinding stage is delivered as fresh material to the second mill of a second grinding stage and finished product is removed from this second grinding stage, and in which the quantity of feed material of this second mill is kept constant when the quantity of finished product alters by altering the quantity of fresh material. This first grinding stage contains an air separator from which the fines are fed as fresh material to the second mill. In the event of alteration in the quantity of fresh material for the second grinding stage the quantity is kept constant by corresponding alteration of the fineness of separation of the separator of the first grinding stage.

Abstract: A method of reducing the particle size of solid particles is applicable to the production of very fine particles of a wide variety of solids, including alumina hydrate, and comprises milling a liquid suspension of solid particles in an agitated media mill, pumping the milled suspension through a particle size classification device to separate the slurry into a coarse fraction and a fine fraction, the particles of the coarse fraction having a greater median particle size than the particles of the fine fraction, recycling the coarse fraction from the particle size classification device to the input of the mill, and recycling the fine fraction by pumping it to the classification device, wherein recycling of both coarse and fine fractions are continued until solid particles of the desired reduced particle size are produced. Preferably a single classification device and a single mill can be used, and particles having a median particle size of 0.

Abstract: A cutter blade projects tangentially from the peripheral surface of a solid cylindrical rotor for travel along an arcuate path in converging relation to a support surface of an anvil aligned with a horizontal travel path along which scrap lumber is continuously fed by an infeed roller into a cutting zone formed between the anvil support surface and the peripheral surface of the rotor. Oversized solids emerging from the cutting zone below the rotor are separated from a wood chip product of desired size and recirculated to the infeed roller.

Abstract: The invention relates to a method and to apparatus for crushing material for grinding, in which the material for grinding first of all passes in multiple circulation through a grinding stage which operates on the pressure crushing principle and then without further grinding is delivered to a classification stage consisting of two classification assemblies set to different degrees of fineness, the streams of fines from the two classification assemblies being mixed together. By the combination of these two measures a desired flattening of the particle size distribution of the end product is achieved.

Abstract: An apparatus and method for monitoring and controlling the flow of fluid transported solid particles is described. Also an integrated system is disclosed for monitoring and controlling pulverized coal in a non-intrusive manner employing a fluid such as air. The coal flow in each feed pipe is regulated so as to achieve a desired flow balance among the burners in a boiler.

Abstract: A separator for classifying powder with air current, comprises a powder feed pipe and a classifying chamber, provided in said separator; a guide chamber provided at the upper part of said classifying chamber to communicate with said powder feed pipe; a plurality of introducing louvers provided between said guide chamber and said classifying chamber, at which the powder is flowed in from said guide chamber to said classifying chamber through the openings between said introducing louvers together with carrying air; an inclined classifying plate raised at its central part, provided at the bottom of said classifying chamber; classifying louvers provided along the side wall of said classifying chamber, through the openings of which the air is flowed to produce a whirling stream by which said powder fed into said classifying chamber together with carrying air is centrifugally separated into fine powder and coarse powder; a discharge opening provide at the central part of said classifying plate and from which the cl

Abstract: A separator for separating fractions of granular material particularly for use in an interparticle crushing product bed comminution press including an outer conically shaped chamber with means for receiving air and the product to be comminuted at the lower end of the chamber, an inner conical chamber, a second coarse grits outlet leading from the inner conical chamber, a first coarse grits outlet leading from the outer conical chamber, a rotor at the upper end of the inner conical chamber having turbo elements thereon, baffles surrounding the turbo elements, and a fine products discharge from the upper end of the inner chamber with the coarse grits discharge from the outer chamber led back to the inlet of a high pressure interparticle crushing roller mill and the fine grits material discharged from the inner chamber led to a tubular mill.

Abstract: A material separator apparatus for obtaining refined material subjected to a first grind reduction which is moved into the separator where the large and/or heavier particles of the material are separated out and returned by gravity to fall back into the first grind reduction for further reduction while the finer ground material is subjected to a second separation by a rotary separating device having an array of spaced members which allow the passage of particles smaller than the spacing between members and the larger particles are refused passage and fall back for further reduction.

Abstract: A method of reducing the particle size of solid particles is applicable to the production of very fine particles of a wide variety of solids, including alumina hydrate, and comprises milling a liquid suspension of solid particles in an agitated media mill, pumping the milled suspension through a particle size classification device to separate the slurry into a coarse fraction and a fine fraction, the particles of the coarse fraction having a greater median particle size than the particles of the fine fraction, recycling the coarse fraction from the particle size classification device to the input of the mill, and recyling the fine fraction by pumping it to the classification device, wherein recycling of both coarse and fine fractions are continued until solid particles of the desired reduced particle size are produced. Preferably a single classification device and a single mill can be used, and particles having a median particle size of 0.

Abstract: The invention relates to apparatus for delivering material to part of a plant, for example to a crushing and grinding machine, in which the fines are separated out of the feed material passing through the material feed chamber by means of an air stream. In this way a substantial increase in the output of the part of the plant can be achieved.

Abstract: A system comprising a roll press for crushing and partially agglomerating a mineral material, a conveyor means arranged downstream of this press and associated with a distributor device and allowing to recycle one portion of the crushed and partially agglomerated material to the inlet of the press whereas the other portion of the material issuing from this distributor device feeds a second distributor device one outlet of which communicates with the conveyor means to thereby control the amount and density of the crushed and partially agglomerated material recycled to the feed of the press.

Abstract: Fluidized-bed counter-jet mills are gas-jet mills with which extremely fine milling results can be produced with very little wear and tear. An improvement in the milling results can be achieved by cooling the gas jets with a refrigerant, but the improvement that can be achieved is not substantial and the consumption of refrigerant is very high. In order to lower the consumption of refrigerant while considerably improving the fineness of the milled material, the coarse material which is separated by the grader of the mill is cooled by the refrigerant within the fluidized-bed counter-jet mill and fed back into the milling chamber. Liquid nitrogen is the preferred refrigerant with which the sump of the mill is cooled.

Abstract: An apparatus is provided for treating a fibre suspension by screening and fibre-separating mechanical working in the manufacture of papermaking pulp. The apparatus is provided with a rotor arranged within a housing, which rotor is surrounded by a stator. The inner surface of the stator cooperates with the outer surface of the rotor to define a refining gap for the treatment of the fibre suspension. The refining gap is divided into a first treating zone and a second treating zone for the processing of the fibre suspension. An adjustment member allows for adjusting the width of the refining gap within the first treating zone independently of the width of the refining gap within the second treating zone. The refining gap within both the first and second treating zones may be simultaneously adjusted by axial displacement of the rotor.

Abstract: In the case of a composter comprising a drum supported for rotation about a level longitudinal axis thereof, means for driving said drum about said axis, said drum including a peripheral casing which is at least partly in the form of perforated sheet metal panels, a longitudinal conveying device fitted under said drum and able to be driven selectively in opposite directions for selective conveying of compost falling from said drum to a compost deposit and a lifting conveying device arranged at one end of said drum, a charging device arranged in an upper part of the drum for cooperation with the lifting conveyor, the aim of the invention is to ensure the most even distribution of the coarse material along the length of the drum while nevertheless keeping to a simple design of the composter and ease of operation.

Abstract: The grinding chamber of the apparatus has first and second grinding sections having perforate wall sections overlying the outlet of the apparatus. The perforate wall of the first grinding section underlies the rotor of the apparatus and has an arcuate shape. The perforate wall of the second grinding section extends generally tangentially upwardly and outwardly from the downstream end of the perforate wall of the first grinding section. The second grinding section is larger than the first, and may include breaker bars which deflect the material being ground toward the perforate wall of such section.

Abstract: An apparatus for supplying a controlled flow of pneumatically transported solid particles, in particular, pulverized coal, comprises a pulverizer or vessel for containing pneumatically suspended solid particles. A supply pipe is connected to the pulverizer or vessel for removing a mixture of pneumatic gas and solid particles from the vessel. A bend is provided in the supply pipe and an aspirator is connected to the supply pipe at a distance of from one to two pipe diameters from the bend. The aspirator is provided on the outer wall of the bend and is supplied with aspirating gas to draw off an amount of mixture from the supply pipe. This controls the amount of remaining flow of mixture through the pipe. The supply of the aspirator is connected to a bypass line which is connected to the mixture inlet of an injector which is supplied with injecting gas. The supply of the injector which carries the mixture is connected back into the vessel.

Abstract: A pneumatic pulverizer comprises an accelerating pipe for conveying and accelerating powder by a high pressure gas, a pulverizing chamber and an impinging member which pulverizes the powder jetted out from the accelerating pipe through impinging force. The impinging member is provided in the pulverizing chamber as opposed to the accelerating pipe outlet and the impinging member has an impinging surface with a tip portion having a conical shape with an apex angle of 110.degree. to 175.degree.. In this way, powder is pulverized at the impinging surface of the impinging member and dispersed substantially in the entire circumferential direction after impinging and the powder dispersed may impinge secondarily on the wall of the pulverizing chamber.

Abstract: The invention relates to a grinding process and apparatus for the simultaneous production of at least two finished products of differing fineness using a ring mill. Pre-classification is carried out in the nozzle ring by adjusting the air to entrain and carry upwards relatively fine constituents. The coarser constituents are discharged downwardly by gravity and subsequently may be conveyed upwards by an elevator and subjected to a second classification in which at least a proportion is extracted as finished product.

Abstract: The invention relates to a grinding method and to grinding apparatus using a ring mill, in which the air speed in an air ring surrounding the grinding track is chosen to be sufficiently low that a proportion of the material which has already been comminuted to the fineness of the finished product also falls downwards against the air stream and through the air ring, is mechanically elevated and subjected to separation, the resulting tailings being delivered back to the grinding track of the ring mill. Such a solution is distinguished by a substantially reduced pressure loss and accordingly a considerable saving of energy.

Abstract: Pulverizer apparatus is provided for pulverizing solid materials into very fine particles. A cylindrical shell member within the pulverizer housing devides the interior of the housing into central and outer chambers therebetween. A cap disposed above a frusto-conical upper portion of the shell includes a bottom portion closing off the top of the shell and a downwardly depending frusto-conical portion. The latter is mounted in spaced, at least partially overlapping relationship with the upper portion of the shell so as to define a downwardly inclined passageway which opens into the outer chamber. A nozzle assembly, located near the bottom of the housing, produces a plurality of jets of air directed radially inwardly towards the center of the central chamber at an angle such that particles of a material located at the bottom of the central chamber are caused to rise and to impact upon each other so as to provide pulverization thereof.

Abstract: A method and apparatus for pulverizing a material such as sand to a desired particle size. The apparatus has a pulverizing shell in which the material to be pulverized is fed and pulverized. The pulverized fluid-carried material overflows the shell so as to be fed into a settling classifier, where the coarser material settles and is discharged through its bottom opening back into the shell for repulverization. The finer material overflows the classifier and is fed to an intermediate bin, which has its bottom connected to the shell through a valve. When the bin is filled up with the material, the valve is opened so that the material in the bin is returned to the shell. The material is thus circulated through the shell, classifier and intermediate bin. The shell is adapted to be alternately connected to the intermediate bin and a product collector bin by a changeover valve.

Abstract: The invention relates to a method and to apparatus for crushing brittle material for grinding using a roller mill and a material bed roll mill for crushing the material for grinding falling downwards over the edge of the grinding track before it is delivered to the sifter. By the use of a material bed roll mill a considerable increase in the throughput capacity of the apparatus and a significant saving of energy can be achieved.

Abstract: A system for collecting, drying, and comminuting garbage. The garbage is collected and introduced into a hopper. A plurality of heat lamps and sandblasting nozzles are provided on the walls of the hopper. The garbage is dried and comminuted in the hopper. A mesh conveyor is provided for filtering out particles smaller than sand which are delivered by a conveyor for further waste disposal. Particles and sand which do not pass through the mesh conveyor are fed back and delivered under pressure to the sandblasting nozzles.