US2032827A - Method of and apparatus for providing material in finely divided form - Google Patents

Description

March 3, 1936.

N. H. ANDREWS METHOD OF AND APPARATUS FOR PROVIDING MATERIAL IN FINELY DIVIDED FORM Fi led May 28, 1955 8 Sheets-Sheet 1 INVENTOR,

Norw'oml HAmJ rews,

ATTORNEY.

March 3, 1936. N, H, AN 2,032,827

METHOD OF AND APPARATUS FOR PROVIDING MATERIAL IN FINELY DIVIDED FORM Filed May 28, 1955 a Sheets-Sheet 2 INVENTOR,

, MMwvaul BY 74/ 22;, W

ATTORNEY.

March 3, 1936.

N. H. ANDREWS 2,032,827

METHOD OF AND APPARATUS FOR PROVIDING MATERIAL IN FINELY DIVIDED FORM- Filed May 28, 1935 8 Sheets-Sheet 5 6 W M a .L ilk *r', 296 2? I!" I m1 6 I 444444441 (.266 7 I l F 0 a I! #26 7777777777 llllll III/Ill! ll/l/l/ /////Y/\/ /I//// I k 25c INVENTOR,

Norwoad BY 7PM ATTORNEY.

Ma rch 3, 1936. N. H. ANDREWS 2,032,827 METHOD OF AND APPARATUS FOR PROVIDING MATERIAL IN FINELY DIVIDED EORM Filed May 28, 1955 8 Sheets-Sheet 4' K Y O E am m wmm 5 w m w 6 W M a C J w w aw 5 M w .2 o M d 2/ 5 MW T Y W n 2 f. fl L n: "w I 90 O4WM-4M\H aw 6 \II 3 J a \m 3 w ,March 3, 1936.

N. H. ANDREWS METHOD OF AND APPARATUS FOR PROVIDING MATERIAL IN FINELY DIVIDED FORM Filed May 28, 1955 8 Sheets-Sheet -5 ATTORNEY.

March 3, 1936. N. H. ANDREWS METHOD OF AND APPARATUS FOR PROViDING MATERIAL IN FINELY DIVIDED FORM Filed May 28, 1935 8 Sheets-Sheet 6 INVENTOR, Nm'WoaJEAmJtdWS.

75M A m ATTORNEY.

March 3, 1936. I N. H. ANDREWS METHOD OF AND APPARATUS FOR PROVIDING MATERIAL IN FINELY DIVIDED FORM 8 Sheets-Sheet 7 Filed May 28, 1935 INVETOR, NomoJEAmmm BY 77 m ATTORNEY.

March 3, 1936. N. H. ANDREWS 2,032,327

METHOD OF AND APPARATUS FOR PROVIDING MATERIAL IN FINELY DIVIDED FORM Filed May 28, 1935 8 Sheets-'Sfleet 8 Fig. 28

lNVENTOR,

I Patented Mar. 3, 1936 UNITED STATES PATENT OFFICE METHOll OF AND APPARATUS FOR. PRO- VIDING MATERIAL IN FINELY DIVIDED FORM Norwood H. Andrews, Moores town, N. 1., assignor to International Pulverizing Corporation, Camden, N. J., a. corporation of New Jersey Application May 28, 1935, Serial No. 23,801 InGreat Britain November 21, 1933 33 Claims.

692,755, filed October-9, 1933, and Serial No.

741,556, filed August 27, 1934.

An object of the invention is the provision of a method whereby a wide variety of solid materials may be readily provided in the form of a fine powder.

Another object is the provision of apparatus whereby a wide variety of solid materials may be readily provided in theform of a fine powder.

Another object is the provision of improved methods and means for breaking up particles of material.

Among the more specific objects of the invention are the provision of methods and means whereby powders having an 'average and/or maximum particle size which is extraordinarily small may be readily obtained in quantity.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the several steps and the relation and order of one or more of such steps with respect 'to each of the others, and the apparatus embodying features of construction, combinations of elements and arrangement of parts which are adapted to effect such steps, all as exemplified in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings in which:

Figure 1 is a vertical sectional view of one form of apparatus embodying the invention;

Fig. 1a. is a reduced-scale detail view;

Fig. 2 is a plan view partly in horizontal section along the line 2-2 of Fig. 1;

Fig. 3 is a vertical sectional view of another form of apparatus;

Fig. 3a is a fragmentary view illustrating a modification;

Fig. 4 is a horizontal section along the line 4-4 of Fig. 3;

Fig. 5 is a vertical sectional view of another form of apparatus;

Fig, 5a is a diagrammatic view of a modifi tion;

Fig. 6 is a plan view partly in horizontal section along the line 6-6 of Fig. 5;

Fig. 6a is a plan view on a reduced-scale, illustrating a modification; V

' Fig. 6b is a reduced-scale view similar to Fig.1, illustrating another modification;

Fig. 7 is a vertical sectional view of another 5 form of apparatus;

Fig. 8 is a plan view partly in horizontal section along the line 8-8 of Fig.7;

Fig. 9 is a vertical sectional view or another form of apparatus; 10

Fig. 10 is a plan view partly in horizontal section along the line lli|0 of Fig. 9;

Fig. 11 is a diagrammatic vertical sectional view of another form of apparatus; v

Fig. 12 is a diagrammatic plan view thereof 15 with certain of the parts broken away;

Fig. 13 is a diagrammatic vertical sectional view of another form;

Fig. 14 is a diagrammatic vertical sectional view of another form; 20

Figs. 15 and 16 are diagrammatic sectional views on the lines 15-45 and i6-l6 of Fig. 14;

Figs. 17 and 18 are views similar to Figs. 14 and 16', showing another form:

Fig. -19 is a view similar to Fig. 13, showing an- 5 other form;

Fig. 20 is a fragmentary view similar to Fig. 13, showing another form;

Fig. 21 is a. view similar to Fig. 11, showing another form; 30

Figs. 22 and 23 are respectively horizontal and vertical diagrammatic sectional views illustrating another form; Fig. 24 is a view similar to Fig. 23, showing another form; a i

Fig. 25 is a view similar to Fig. 13, showing another form;

Fig. 26 is a horizontal sectional diagrammatic view, showing another form;

Figs. 27 through 31 are diagrammatic ver- 4.0

tical sectional views, showing various other arrangements embodying; the invention; and

Fig, 32 is a diagrammatic sectional view showing another arrangement.

A wide variety'of types of pulverizing methods 45 and apparatus have been proposed in the past. Certain of these have utilized fluid energy to effect the pulverization. Of these, the most effective have been pulverizers of the type wherein material in the form of large granules is thrown 50 1 against a plate or wall and broken up by impact, and pulverizers in which particles are thrown toward each other by two or more converging streams. Impact pulverizers are, however, subject to the difliculties that the plate wears out" rapidly, that often the plate material becomes undesirably entrained with the material being pulverized, and that the pulverization for the most part is undesirably coarse for many desired uses. Converging streampulver'izers are subject to distinct limitations because of the difilculty in getting the material into the streams at the points of the greatest energy content, in getting it into the streams in a uniform manner, in the wastage of energy by the slowing down of particles which reach an opposite stream without impinging upon other particles, and also in getting the material which is not reduced to the desired fineness back into the stream.

With a view to overcoming the foregoing and other difilculties, the present invention provides a procedure and means whereby a. highly efficient utilization of fluid energy may be obtained, and which permits material to be obtained in powder form such that all the particles are of exceptionally small dimension,-for instance 40, 20, 10, 5, 4, and in some cases 2 microns more or less, depending upon the material treated and the results desired.

While the fineness of the powders which have been obtained in accordance with the invention varies with different materials, the invention has enabled the provision of a large number of materials in the form of powders much finer than could be produced by previous commercial apparatus and procedures, and has made possible an extraordinarily efilcient production of fine pow ders. In accordance with the invention, moreover, many materials heretofore considered diflicult or impossible of commercial production in the form of fine powders can be readily produc in finely powdered form by means of the in" tion.

The invention contemplates the eflfectuation of pulverization by the use of fluid energy in a highly efiicient manner which is far out of the range of previous pulverization, and/or the utilization of a pulverizing vortex in such a manner that the material may be classified in an extraordinarily thorough and eifectiv'e manner. Preferably there is provided a procedure and means whereby both a highly efilcient pulverization and a highly effective classification is obtained; but either such highly eflicient pulverization as may be obtained in accordance with the invention or such highly effective classification as may be obtained gives results which could not, so far as is known, he obtained without the use of the invention. In accordance with the invention the gaseous fluid may be introduced into the outer portion of an 'inwardly spiralling vortex in a direction which will maintain the vortex and under such conditions that the energy of the fiuid will be very high with respect to the amount of fluid introduced, so that the introduced fiuid will have a high velocity to impart high speeds to particles coming under its influence, and so-that the speed of rotation of the vortex will be very high compared with its component of inward movement; as by. discharging fluid into a vortex chamber under high pressure through an opening or openings of small extent. Because of the high speed given to the particles a great breaking or tearing effect is exerted thereon as they impinge upon other particles (or upon the walls of the chamber) and because of the high rotative movement of the fluid and its relatively low inward movement there will be a large tendency to return to the outer portion of the vortex for further grinding action such undesirably large particles as are thrown or bounced into, or as otherwise reach, the inner portion of the chamber.

It has been found that the introduction of a multiplicity of small streams of gaseous fluid in a direction having a component of movement which will maintain the vortex and a component of movement which is transverse to the vortex effects a pulverization of an order far beyond that which it has hitherto been thought possible to obtain, since a large number of particles moving in a variety of difierent directions will be continuously impinging upon each other at a high speed with great breaking or tearing effect. The introduction of even one small, but somewhat larger, stream has this effect, but in considerably less degree. It has likewise been found that the provision of a vortex which spirals inwardly at a high rotative speed but at a low inward speed results in maintaining the larger particles in the zone of active pulverization most of the time so that they can be repeatedly acted on by the' stream, while at the same time permitting the finer particles to work inwardly so that they will not cushion the pulverizing action and so that they will reach an inward point where they can be readily withdrawn. It has also been found that by continuing the inward movement of the vortex through a radially extended zone inwardly of the zone of active pulverization, a highly effective classification of product may be obtained, so that substantially all the particles entrained by the fluid which is withdrawn at an inward point will be of very small and, if desired, exceedingly small size. It has likewise been found that the axial extent of the vortex must be limited so that the fiuid movement in diflerent axial positions in the vortex will be substantially the same so that the streams may perform their work efiectively so that particles may not gather at points where they will reenter the vortex in large masses.

Accordingly, the invention permits material to be pulverized in a much more eificient manner than was hitherto possible regardless of whether such a product. having an exceedingly small particle size is to be provided by the use of the same vortex, is to be obtained as a separate step, or is not essential for'the requirements of a particular case. Likewise the. invention permits material to be classified so'as to obtain a product of average or maximum particle size much lower than was heretofore possible, regardless of whether the material is efilciently pulverized in accordance with the invention, has been pulverized initially .to agreater or lesser extent, or is found naturallyin a fairly fine but unclassified condition.

A considerable amount of pulverization and a considerable amount of classification will always be obtained in accordance with the invention, regardless of the particular procedure, or apparatus in which the invention is embodied, but it is not essential for anumber of purposes that highly eificlent pulveriza'tion and highly effective classification be both obtained. Highly improved pulverization, highly improved classification, or both, may be obtained in accordance withv thevinvention.

Further in accordance with the invention, a

Further in accordancewith the invention the maximum particle size, the average particle size, the efiiciency ofseparation for particular purposes and other features may be effectively controlled.

In carrying out the invention there are utilized certain combinations or subcombinations of steps under various conditions whereby one or more of the highly advantageous results sought may be readily obtained.

Gaseous fluid may beintroduced into the outer portion of an inwardly spiralling vortex at a high velocity in a manner which will maintain the vortex at a high rotative speed and arelatively small inward speed. It is preferable that a plurality of such streams or jets be introduced to give a better balanced vortex, and it is highly desirable for the best results that a multiplicity (3, or ordinarily more) of such streams be introduced, but in certain instances, under proper conditions, the fluid may be introduced in a single stream. Likewise, while fluid may be introduced in certain instances in a direction having no substantial transverse component of movement, it is distinctly preferable for obtaining the most satisfactory results from a pulverization standpoint that the fluid be introduced in a direction having both forward and transverse components of movement. By giving each of said streams a component of movement which is forward in the direction of rotation the vortex will be maintained, and by giving them a component of movement which is transverse to the direction of rotation a large number of particles will be causedto move inwardly at a high speed to impinge upon the particles moving in the direction of the vortex, to be carried into the body of the vortex for impingement upon particles moved inwardly by other streams, to be driven into collision with particles moving in the direction of another stream, if the lines of the streams intersect to a greater or lesser extent, or to be driven toward the centre of a succeeding-stream so as to be given a higher velocity than could obtain near the periphery of a stream where they would be more sidered to involve the steps of forming an inward- I 1y spiralling vortex and introducing a stream or streams into the vortex;

In order to obtain the highly effective action which the present invention makes possible, it isv of importance that the vortex be axially confined to an extent such that the vortex will have a high rotative speed and a relatively small inward speed so that the centrifugal action will be large in comparison to the entraining force, and at the same time such that there will be no substantial escape of particles from the active influence of the high velocity streams, of the high speed vortex, and of eddies created thereby, to positions from which they will re-enter the vortex in large masses; and the terms "axially confined and narrow as used herein in reference to the zone or zones in which pulverization and classification occurare to be understood as referring to zones having such an axial extent. In this manner, particles carried by the vortex will be almost continuously acted upon in a substantially uniform manner, and the vortex speeds will not vary substantially from time to time. It is, however, to be understood that escape and controlled re-introduction of the particles in a manner which does not result in material variations of the fluid load does not subcomponent. Whether the transverse components of the streams referred to hereinafter are radially inward, axial, or'outward, or combinations of these, they will be spoken of herein as being introduced into an inwardly spiralling vortex, since regardless of what the relative disposition of the stream and the vortex proper may be if considered technically, the result. of cutting into a vortex which carries particles of material and spirals inwardly is secured. As above pointed out, the stream or streams should be introduced into the outer portion of the vortex, since the centrifugal action will tend to keep a large number of particles in this outer portion, which particles will be kept in activity by the streams and by the vortex, so that a very large number of collisions or fracturing or tearing contacts will continually occur.

Whilematerial pulverized in accordance with the invention may be classified in any desired manner, it is distinctly preferable to classify the material in an axially confined zone of the vortex disposed substantially radially inwardly of the zone of active pulverization. In this manner, the,

high speed whirling of the vortex is maintained, and substantially all particles above exceedingly small sizes may be carried outwardly by the cen-" trifugal action of the inwardly spiralling vortex. Not only will particles which are fairly fine, but nevertheless larger than desired, be thrown outwardly by the vortex as its angular movement increases as it spirals inwardly, but large particles which are thrown inwardly by the streams to a point beyond the zone of active pulverization will be returned to the latter zone to be further acted upon. The greater the radial extent of the classification zone, the finer will be the product obtained, other conditions being equal or compensated for. It is not essential that the classification of material be effected exactly radially inwardly of the zone of active pulverization and indeed it is preferable'in many instances that it have a different axial extent than the pulverization zone, but it is of distinct importance that the classification zone be disposed substantially radially inwardly of the pulverization zone, so that the high speed whirling action will be maintained in this zone, and so that it will include no axially-extended portion in which particles may gather without being returned more or less individually to the pulverization zone, and from which particles would be returned by gravity,-

vortex action, or otherwise to the active zone in batches or large masses with the result that the material would overload the vortex. Within lima particle will be pulled inwardly to a lesser ex-.

cation zone.

its, however, effective control can be exercised by varying the axial extent of the classification zone, preferably in a manner which does not involve sharp changes in extent from an outer to an inner point. By increasing the axial extent of the classification zone the vortex is caused to extend axially, so that its inward component of movement and consequently its entraining effect is diminished while its rotative component of movement remains substantially the same, so that it 'will have the same centrifugal action. In other words, when the pitch of the spiral is small,

tent than if the pitch is large, whereas its tendency to move toward the periphery under centrifugal action will be undiminished. The provision of this control feature accordingly permits the provision of a finer product. In instances, however, where a uniformly coarse product is desired, it is desirable that the classification zone be additionally confined axially to a more or less small extent, as for instance to a smaller extent than the axial extent of the pulverization zone. In this case the entraining effect will be greater so that fairly coarse particles may be withdrawn without being returned to the pulverizatlon zone.

As above indicated, while the classification step is preferably practiced in conjunction with a pulverization procedure such as above described, it may be utilized in conjunction with modified pulverization procedures and in other ways in certain instances to give highly satisfactory results.

Fluid and entrained particles may be withdrawn from a radially inward portion of the vortex. This may be either from a portion in proximity to the pulverization zone in instances where classification is not of importance, or preferably, from a portion disposed inwardly of the classifi- Entrained particles may be separated from the withdrawn fluid in an exceedingly 'tex. Furthermore, when desired, the particle size may be controlled by controlling the amount of material fed to the vortexa decrease in the amount of material fed in acting to decrease the circulating load and resulting in a finer product.

Material may be supplied to the vortex at any of a wide number of variously disposed positions,

' since the centrifugal action in the vortex will cause the coarser particles of freshly supplied material to work outwardly into the active influence of the high velocity streams even though they are supplied at a relatively inward point. It is of importance in order to produce a fine product, however, that the supplying of material be carried out so that the entraining force of the withdrawn fiuidwill not act to entrain the coarse particles introduced. Material may be supplied at the periphery, or at any inward position which is sufficiently-spaced from the withdrawal opening or openings so that the entraining force at this position will not be sufficient to entrain the coarse particles, so that they will be moved outwardly by centrifugal action. when material is supplied at a point outwardly of the axis, it may in most instances be supplied at a single point, but since such a procedure results in a more or less slight unbalancing of the vortex, it is prefcertain amount of pulsation in the feed will ordinarily not be harmful so long as the supply at any time isnot sufficiently great, and so long as the intervals between the intermittent supply of material are not sufiiciently large, so that substantial variations in the circulating load will occur. v

The velocity of the introduced streams may vary considerably but should be of a high order. Such velocities are ordinarily-obtained by applying high fluid pressure to a nozzle to release a gaseous fluid such, for instance, as steam or air, through the jet opening of the nozzle.

It is to be noted that the particles in the body of the vortex are ordinarily widely spaced from each other, with the result that each particle will be given a high speed by the fluid in proximity to it. It will be appreciated that a few particles may sometimes move together but that these will act substantially as individual particles under the circumstances being considered. The spacing of the particles will be less toward the periphery of a chamber in which the vortex is formed, and may be so closely spaced at the periphery that their movement will be markedly slowed down. However, these particles appear to be again picked up by the jets and/or by the turbulent condition in the outer portion of the chamber and returned substantially as indivld-' ual particles to the body of the vortex. In this connectiomit is to be noted that it is of impor-- tance that the jets be so introduced that their high velocity portions will directly act upon material concentrating in proximity to the periphcry of the chamber, so that the vortex will not be slowed down by the weight of material which is not actively'affected by the streams.

A further understanding of the operation may be had from the following data concerning a desirable type of operating conditions and of pressure measurements taken in an unloaded vortex. In utilizing a cylindrical pulverizlngchamber 12 inches in diameter and 2 inches high and by introducing a jet of-steam under pressure of 90 pounds per square inch at a temperature of 450 F. through a single nozzle ll of an inch in diameter, (giving an initial critical velocity of approximately 1600 feet per second) the static pressure of the steam. dropped to slightly above atmospheric pressure so that the pressure in the chamber varied from a pressure of about 4 pounds at a point 5% inches from the'axis of said chamber to a pressure of less than two pounds at a point 2% inches from said axis; that the linear velocity of the steam at said outer point was 843 feet per second as compared with 720 feet per second at said inner point; that the angular velocity of the steam at saidouter point was 280 R. P. S. as compared with 610 R. P. S. at said inner point; and that the centrifugal force developed at said outer point was 46,000 times the static weight as compared with 86,000

' at said inner point.

Procedures such as contemplated by the invention are further exemplified in connection with the exempliflcation'oi apparatus embodying the invention.

One form of apparatus as contemplated by the invention and one manner of carrying out the procedure as contemplated by the invention, when materials are to be both pulverized and classified, and also separated from the fluid, are illustrated in Figs. 1 and 2. While ordinarily the operation is carried out with the parts positioned as shown, it is to-be understood that apparatus embodying the invention, and vortices formed in accordance with the'invention, maybe arranged to operate at any desired angle to the vertical, and with the collector unit, if used, on

any desired side of the chamber. In the exemplifled apparatus, there is provided a lower plate 2| and an upper plate 2| providing therebetween a pulverizing and classifying chamber 22, the periphery of which is closed by an annular header 23; Fluid under pressure is introduced into the header through a pipe 24, which may extend to any suitable source of fluid pressure,

such, for instance, as a steam boiler or air com- I pressor. The inner wall of the header is formed with a-multiplicity of small jet openings 25, (16 in the present instance) which are formed at angularly'spaced points, aswill be seen from Fig. 2, to release gaseous fluid at a high velocity in a direction as indicated by the lines A in Fig. 2, having a component'which is forward in a "direction of rotation within the chamber 22 and a component which istransverse to that direction (inward as exemplified) and will cut across the lines of vortical movement in the outer portion of the chamber. As will be apparent, 'this arrangement serves to provide discharge means comprising orifice means and gaseous-fluid conducting means directly behind said oriflce means and having an eflective area greater than the cross sectional area of the orifice means. The pipe 24 may be provided with a valve 24 so that the pressure in the header 23 may be regulated. In order to provide material for the streams and the vortex maintained thereby to work upon, there is provided feeding means which, in the present instance, comprise a multiplicity'of supply openings 26 (8 in the present instance) in the plate 2|. As exemplified eight such openings are provided at evenly spaced points and are formed to admit material in a direction which is forward in the direction of rotation maintained by the jets of gaseous fluid from the jet openings 25, as will be seen from Fig. 2. -To simplify the feeding of material through the openings 26, these openings are surrounded by a feeding head '2'! into which-material to be pulverized ,is fed under relatively slig'ht fluid pressure by an injector-type feederconstruction 28. This comprises a hopper 29, which may be fed by a feedcontrol means 29', and by which coarse material to be pulverized is introduced into a conduit 30 in which there is disposed a nozzle 3| by which fluid under pressure is released just beyond the opening from the hopper. This fluid carries the particles of material through a Venturi passageway 32 and into the feed head 21. The introduced material spreads around the feed head and en-v ters the various openings 26 in a substantially uniform manner being forced into the header under the pressure established therein by' the fluid from the nozzle 3|. It is desirable that the amount of fluid entering through the nozzle 3| be restricted to that necessary-to carry the desired quantity of material into the feed head 21 and into the chamber 22, and also that the for the pulverized material.

the amount of the fluid supplied through the feeding means 23, so that there will be no undue 7 pressure drop between the feed head 21 and the chamber 22. The openings should, however, be sufliciently small so that the materials will be fed to the various sectors of the'chamber 22 through the yarious openings with substantial uniformity. At an inward position there is provided an opening, by which the chamber 22 communicates with a collector member 36, and through which fluid and entrained particles may be withdrawn. The lower end of the separating chamber is' constricted to a removal opening 31 Opposite the opening 35 and co-axial therewith is a smaller circumference opening 38 at'the end of a conduit 39 through which freed fluid may be withdrawn. By the provision of an opening 33 opposite the opening 35 and a conduit 33 leading in a direction opposite to the directionpf movement of the many 01' the dimensions may be widely varied,

nevertheless too great a variation in certain of the dimensions will result in undesirable and sometimes disastrous results, as will be hereinafter indicated. Accordingly there are indicated below the dimensions of various of the parts of a particular device such as shown in Fig. l which has given highly satisfactory results when utilized with various readily available types of pressure-supplying means. In this instance. the diameter oi the vortex chamber was 36"; its axial extent at the periphery, 2 its axial extent under the feed head, 3"; the difference in height in the top plate at the outer and inner edges of the portion! l, 3"; and the extent of the opening 35, 12"; and of the opening 33, 7". The jet openings were fiths of an inch in diameter, the supply openings were in diameter,- the nozzle 3| was ftths of w inch in diameter, and the Venturi opening at its smallest of an inch in diameter. It is to be noted that the openings need not be round, but may be of any desired shape. v

The operation of the device as deduced from theoretical considerations, from the wear on devices which have been in operation for various lengths oi time, from the resulting product, from inspection of the particles deposited on the floor oi the device when the operation is stopped, from scratches in a'fllm of material adhering to the surface of the metal in some cases, and from mathematical computations, is indicated below.

The high fluid pressure applied to the header 23 results in the'ejection of streams or'jets of gaseous fluid at a very high velocity through the other particles moving in other directions including the direction of the vortex. At the same time that there will always be a considerable number of particles moving about the outside of the chamber 22 and along its peripheral wall .to be carried inwardly by the jets. Some of these particles will be picked up near the periphery of the streams and moved forwardly and inwardly at varying rates of speed. Others will probably enter the body of the stream and will be hurled violently inwardly. The particles will be repeatedly acted upon until reduced to the desired size. All the speeds in question, as will hereinafter be more fully apparent, will be high and the vortex itself will impart a high speed to the particles moving with it, so that particles moving in the direction of the streams and moving in the direction of the vortex will impinge upon one another at speeds which will fracture or tear the pieces in a highly effective manner. The velocity of a considerable number of "particles will be increased by the streams and given a direction partaking somewhat of the direction of the stream (without necessarily exactly following the lines A), and certain of these particles which tend to move toward a succeeding stream will. because of their increased velocity, enter the central portion of the succeeding stream and will have their velocity further increased. It is to be noted that the lines A cross .each other, so that particles moving in the direction of one stream will impinge upon particles moving in the direction of a succeeding stream, with the result that a still further increase in pulverizing action is obtained. Certain of the particles will approach an opposite wall and impinge upon particles near the wall. Some will impinge upon the wall itself and be broken up there, but this, as indicated by the wear on the wall, occurs in a relatively small number of instances. Since the vortex is axially confined, there is no tendency for particles to concentrate in positions where they will re-enter the body of the vortex as a batch of such character that it will harmfully unbalance the vortex. This appears to be due to the eddy action in proximity to the streams entering the vortex, and from the high speed action of the axially confined vortex itself which keeps all the particles in substantially continuous movement. It is to be noted that what constitutes proximity will be relative, and will encompass a greater extent for larger size vortices into which larger size streams are introduced, and will also depend on other factors, including the positioning of the streams and their main pulverizing effect is in the outer portion of the chamber where particles are being thrown continuously against one another at high speeds with great pulverizing effect. At a portion of the chamber disposed substantially radially inwardly of this outer zone of turbulence, the direct effect of the streams diminishes, and there is provided a zone wherein the vortex spirals inwardly without the turbulence present in the outer pulverization zone. In this inner zone of the vortex, the material is classified by the centrifugal action of the vortex and all particles greater than a desired size (which may be exceedingly small) are returned to the outer zone by the centrifugal action. The classification of material in a zone disposed radially inwardly of the pulverization intermittently overload the effect on the vortex. The"- zone results in only the smallest particles being carried over with the fluid through the'opening 35, and the utilization of the same vortex to pulverize and classify, results in highly efficient and effective action. Since the classification zone is axially confined, an exceedingly effective classification is secured, since the high speed rotation of the vortex'continues as the vortex spirals inwardly toward the outlet opening, and also there 'is no possibility for batches of the material to build up and fall or otherwise work back so as to vortex and interfere with the classifying action. It has been found, however, that it is of advantage, in many instances, to provide a chamber wherein the axial extent is somewhat greater toward the inward part thereof than at the periphery so as to decrease the inward component of the vortex and thus reduce the entrainment effect of the fluid when compared to the centrifugal force, so that when desired a finer product may be secured, other conditions being equal. To this end, in the present instance, the axial extent of the chamber is increased somewhat by the upward bend l and still more by the to be noted that there will be considerable eddy action along the walls even in the classification zone, so that material tending to work toward or along the wall 4| will be caught up by these eddies or by the vortical movement sufliciently so that they will be subjected to the strong centrifugal action and carried outwardly again if they are larger than desired. Desirably there is obtained additional insurance against particles working inwardly along the walls by providing the openings, such as 35 and 38, at a point somewhat inward of the walls so that the members 36 and 39 will form ducts, the walls of which act as barriers to the inward movement of particles along the walls. However, as indicated, the provision of such ducts is not essential and they may be dispensed with in a number of cases.

The fluid, as it spirals inwardly, finally reaches the opening 35, by which time all except parupward bend 41. It is.

will be hereinafter ticles of the desired size will have been eliminated. The fluid, with its entrained fine particle s, spirals into the collector chamber its vortical motion so that the energy of the vortex formed and maintained by the streams will be utilized to free the fluid from the fine particles which it has carried into chamber. now moves is axially extended, the inward component of the vortex is much less than it was in the vortex proper, so that avery high percentage of the entrained particles is readily separated 36, retaining the collector Because the zone in which the fluid.

from the fluid by centrifugal action. This is true even for very fine particles which have been withdrawn after a classifying action in accordance with the invention, since the increased whirling action which will be effective to provide a more intense classification will atthe same time provide a greater whirling action in the separating duit 39 to a suitable point of discharge. The separated particles work along the walls of the collector chamber to the opening 31, which may be covered with a bag or other suitable receptacle to receive them.

It is to be noted that in the present instance the classification zone is extended a considerable radial distance, so that a highly effective classifying action may be secured even with materials which are diflicult to classify either from the standpoint of eliminating particles somewhat coarser than desired, or of eliminating especially coarse particles which may be thrown inwardly by the jets with especial force. It is to be noted also that the chamber does not materially increase in axial extent for a considerable distance inwardly from the periphery.

Particles of material to be acted on are fed to the vortex thru the openings 26 in a forward direction. When the fluid used is steam, it is undesirable to begin supplying material until sufficient time has elapsed so that the entire apparatus is hot and dry.

In Figs. 3 and 4 there is illustrated in a general manner a varied purpose construction exemplifying another method of carrying out the invention and illustrating a number of possible variations. In this exemplification there is provided a lower wall 20a and an upper wall 2 l a providing therebetween a chamber 22a. As will be observed, the lower wall 20a is adjustable, and the entire construction is enclosed in a casing 42 of which the wall Zla forms a part. At the periphery of the chamber 22a there is provided an annular wall 43 having a series of openings 44 disposed at angularly space'd points therein. These openings, as exemplified, are shaped to ad mit streams of fluid in a direction similar to the direction of the streams from the openings 25 in Fig. 1, and back of the openings 44 there are provided nozzles having jet openings 25a arranged to eject small streams of fluid through the openings 44 in a direction generally similar to the streams from the openings 25 and having a component which is forward in a direction of rotation within the chamber 22a and a component which is transverse to this direction (in this case, inward). These nozzles are connected by high pressure connections to a header 46, to which fluid under pressure may be delivered through a valve controlled pipe 41. As will be apparent,

- the -nozzles 45 terminating in the jet openings 25a serve to provide discharge meanscomprising oriflce means and gaseous-fluid conducting means directly behind the orifice means and having an effective area greater than the cross sectional area of the orifice means. Material is supplied to the chamber 22a through a single opening 26a from a feeding means 28a comprising a chute or hopper 29a by means of a jet of fluid from an injector nozzle 3la. At an inward position there is provided an opening 35a leading into a collector member 36a, the lower end of which is constricted as at 31a and is closed by a counterweight flap valve 48. An opening 38a similar to the opening 38 is provided at the end of conduit 39a through which fluid may be withdrawn. The

opening -38a is of smaller circumference thanthe opening 35a and these openings are in effect oppositely disposed, though the collector member 36a extends beyond the end of the conduit 39a in the present instance. This latter feature is of assistance in certain cases inassuring that the whirling fluid will have a downward component as it enters the collector.

In the present instance, there is provided a flanged ring 49 to afford additional assurance against larger particles at the lower inside portion of the chamber 22 being deflected upwardly toward the top wall Zia. where under certain conditions they might be carried over into the collector member through the opening 35a.

As above indicated, the lower wall 20a is vertically adjustable as by screw and nut construction indicated generally at 50 so as to permit the axial height of the chamber 22a to be varied to adapt a device for the more satisfactory treatment of various materials under various conditions. For example, when a material of a lower specific gravity is being treated, it is generally desirable that the axial height of the chamber be greater so as to permit a greater volume of this light, readilyentrained material to be acted on by the vortex. Similarly, a greater axial extent is generally desirable when the material-is soft and easily acted on effectively by the vortex. In this connection, it is to be noted that in the treatment of an especially light, readily frangible material in a vortex having a vertical axis, it is desirable to introduce the fiuid nearer the bottom of the chamber than the top in order to maintain all of the material in active circulation and prevent a layer settling on the bottom wall. For

this purpose and also to provide a construction which is adapted for operation under a wide variety of conditions, there are provided in the wall 43, if desired, in a plane below the plane of the opening 44 a series of similar angularly spaced openings 44a: adapted for the reception of nozzles such as the nozzles 45. If desired also, the header 46 and nozzles 45 may be adjustable, as by a screw and nut construction indicated generally at so that the same nozzles 45 may be shifted so as to be disposed opposite the lower openings instead of opposite the upper openings if desired.

It is to be noted that an annular chamber 52 is formed between the wall 43 and the casing 42, and that, in the present instance, the Wall 43 does not extend all the way to the upper wall -2l, but leaves a communicating space 53 between the chamber 22a and the chamber 52. Some of the particles in the top of the chamber 220. will accordingly be carried over into the chamber 52 by the centrifugal action of the vortex in the chamber 22a. These particles will fill the chamber .52 until they reach the level of the nozzles and will, when the nozzles are disposed opposite the openings 44, tend to fill the chamber up to a line 54. Accordingly, during continued operation, the nozzles will act as refeeders and will carry material from the chamber 52 back through the openings 44 into the chamber 22a, thus feeding material to the various sectors of the vortex as Well as to the sectorin which the opening 26a is formed. It is to be noted that this action does not, under proper conditions, interfere with the action of the vortex or with the substantial maintenance of all loose particles continuously in motion by the whirling fluid, as above indicated, since the vortex cannot pick up masses of particles from the chamber 52. As above indicated, it is important in certain instances that the feed to the various portions of the vortex be relatively or substantially uniform, and the exemplified construction assists in obtaining this result. If greater'uniformity is desired, it may be obtained without substantial modification of the construction shown. The supply opening may be located to discharge all of the fresh material to be pulverized directly into the chamber 52 instead of directly into the chamber 22a, as indicated in Fig. 3a, which shows a construction exactly similar to that shown in Fig. 3, except that the feeding means is located as indicated at 2811 to empty thru an opening 16b into the chamber 52. r

In order to prolong the life of the apparatus, the wall 43 is formed of hard, wear-resistant material, and the lower and upper walls 20a. and 2m may be provided with replaceable liner portions of hard wear-resistant material. As will be observed, the wall member 43 is likewise removable and replaceable.

In carrying out the invention by the use of an apparatus such as shown in Figs. 3 and 4, the action is in general similar to the action in the device shown in Figs. 1 and 2. The streams of gaseous fluid from the openings 25a move in general as indicated by the diverging lines from the jet openings, the amount of spread dependin upon the amount of the material in the chamber and other factors, it being appreciated that no exact knowledge of the precise fluid movement in the chamber under operating conditions can be obtained. Under the influence of the streams and of the movement of the vortex set up thereby, an individual particle may move in a circular undulatory path, suggested by the line B, until it is broken up by impingement against another particle, tho probably many of the particles will take a much more varying course and, due to centrifugal action, will tend to work out as suggested by the lines C to positions near the periphery of the chamber whence they may be thrown inwardly again by the jets. The entire mass of particles and fluid in the chamber will whirl rapidly, the particles being for, the most part in a continuous rapid movement in and about the chamber with the result that particles moving rapidly in various directions will be continually impinging upon each other and being broken or torn into small pieces. It is to be noted that the directions of adjacent streams intersect in this instance also. The coarser particles are repeatedly acted on by the streams until they are broken up. As was the case in Figs.- 1 and 2, the inner portion of the vortex serves to classify the material and to eliminate the coarser particles; the

' troduced by a pipe 240.

fluid and the entrained fine particles passing into the collector member 36a through the opening 35a. The vortical movement is utilized elfflciently within the collector or separator member 36a to free the fluid from the entrained particles in the manner previously indicated, and the freed fluid is carried off through the conduit 39a. Material is supplied to the chamber either through a 28a in Fig. 3, or as indicated in Nb of Fig. 3a. By the provision of the injector 3la, material is fed in against such'pressure as may exist in the chamber to which material is supplied.

In Figs. 5 and 6 there is shown a simple form ofconstruction which is satisfactory for use in accordance with and for carrying out the invention in many instances. This construction com.- prises a lower wall 200 and an upper wall He between which there is povided a vortex chamber 220, the periphery of which is ,provided by a header 230 to which fluid under pressure is in- Inthe inner wall of the header thereare .provided at angularly spaced points a multiplicity of small jet openings 25c through which gaseous fluid is discharged into the chamber at a high velocity in directions havmember 360 equipped material used above,

feeding means such as indicated in.

ing a component of movement which is forward in a direction of rotation and a component of movement which is transverse to this direction, as indicated by the lines D in Fig. 6. Material is fed to the chamber 220 through an opening 260 by a feeding means 280 comprising a nozzle Me, which acts to drive material from a chute or hopper 29c thru a venturi opening 32c and thru the supply opening lie. The upper wall 2lc slants upwardly as indicated at Me to provide an I increasing axial extent at the classification zone.

The oblique disposition of a wall portion, such as at c, facilitates the return to the pulverization zone of larger particles working against this wall. The fluid and entrained particles are withdrawn through an opening 350 into a collection at its reduced lower end 31c with an extension 51, to which a bag or other suitable receptacle, indicated at 58, may readily be fastened. Freed fluid is withdrawn through an opening 380 into a conduit 39c and carried off thereby to a suitable point.

It will be apparent that, if desired, a plurality of feeding means may be provided, and in Fig. 60. there are shown two such feeding means indicated at 28c and "co, which act to feed material through supply openings 26c and 26cc, respectively, to opposite sectors of the chamber.

One form of mill proportioned as in Figs. 5 and 6 which has given satisfactory results is one where the diameter of the chamber 22c is 12", the axial height at the periphery being 2", the diameter of the outlet opening 350 being 5", and the diameter of the outlet opening 38c being 2 /2". In this apparatus 8 nozzles having jet openings in diameter were utilized. The opening of the injector lie was A" in diameter and the opening of the venturi 320 was As above indicated, the proportions of a vortex chamber or the dimensions of a vortex pro-; vided in accordance with the invention may be varied considerably so long as the various conditions for eifective operation as indicated herein are complied with. For instance, a construction such asshown in Figs. 5 and 6 gave excelof purposes were obtained at the same rates of feed, although the product was markedly coarser I under the 55 in each instance. When, however, same conditions of operation on the particular the height was similarly extended another 2 inches, the classification was unsatisfactory, and the product contained a considerable percentage of unpulveriz'ed particles at 4 corresponding ratesof feed.

In this connection it is to be noted that in embodiments of the invention wherein the axial ex-' tent of the pulverization zone is relatively large a better action may be obtained by injecting the 6 streams at a plurality of axially spaced points so that the streams and the vortex will more positively act on the particles throughout a larger axial extent of the vortex. An arrangement of this nature is shown diagrammatically in Fig. 5a 7 wherein, there is exemplified an arrangement which is similar to that shown in Figs. 5 and 6 with the axial extent at the periphery doubled as indicated above, except that two rows of jet openings 251! and 252 are provided. As exemplified, 1

I arrangement shown in Figs. and 6.

As above indicated, while a plurality of evenly spaced streams are preferably utilized to give a balanced action, it is not essential to the carrying out of the invention in certain instances that more than one stream be utilized to maintain the vortex and to throw particles into impingement with particles carried by the vortex. There is exemplified diagrammaticallyin Fig. 6b an embodiment of the invention wherein the construe tion is similar to that shown in Figs. 5 and 6,

except that a single jet opening 250' is provided to discharge high velocity gaseous fluid into the vortex chamber 220 instead of a multiplicity of jet openings c. The particles are hurled into the chamber by the stream passing through the opening 250' and impinge upon such particles as are carried in the vortex. While the number of particles carried in the body of the vortex at the time the stream enters the vortex will be less than would be the case in a vortex formedin the chamber 220, they will nevertheless be sufficient so that a good pulverizing action is obtained. It is desirable that the jet opening be made of such size that an effective rotative speed will be maintained. The area of the opening 25c i may be commensurate with the combined area of the openings 250. The use, in the grinding of limestone, of a construction such as exemplified wherein the opening 25c was 5*;- inch in diameter and wherein the other dimensions were those indicated in connection with Figs. 5 and 6, gave a product wherein the size of the particles was larger than the size of the particles obtained by the use of a construction such as shown in Figs. 5and 6, but a satisfactory product for many uses was nevertheless obtained.

Another embodiment of the invention is exemplified in and by Figs. 7 and 8. In these figures there are provided side walls 20dand Zid, providing therebetween a vortex chamber 22d about the periphery of which there extends a header .2301, to which fluid under pressure is introduced through a supply inlet 24d. A liner 60 of hard wear-resistant material forms a surface for the wall 20d and carries an upwardly extending flange GI providing a wear-resistant peripheral surface. The wall Zld is composed of a plate of hard wear-resistant material, which can be removed and replaced as desired. A multiplicity of openings 62 are drilled in the header and in the flange 6| at angularly spaced points and in a direction generally similar to the direction of the openings 44 and in these openings there are secured nozzles 63 having jet openings 25d directed generally similarly to the openings 25. In the present instance, material is fed to the chamber 2212 through a peripheral feeding means M. This feeding means comprises -a hopper 29d from which material is fed by an injector nozzle 3ld through a Venturi construction 32d and into the chamber through a single opening 26d This type of feeding means utilizes the energy from the injector nozzle to assist in maintaining the vortex and likewise brings the material into a vortex in' a position where it will be acted upon by the jets with particular facility. The fluid and entrained partcles pass out of an opening 35d into a collector member 36d in which the material is separated from the fluid, and the materialcollected in a container, the top of which is indicated at 65, the freed fluid passing out through an opening 38d and the conduit 39d.

5", and oi. the opening 38d, 3"; with the other dimensions substantially in the proportions shown. Ten nozzles having 2" jet openings may be provided. The injector nozzle may have a similar opening and the Venturi opening may be Still another embodiment of the invention is illustrated in and by Figs. 9 and 10. In this con.- struction a vortex chamber 22c is formed between a lower plate 20c and an upper plate 2| e, which in the present instance extends directly inwardly from its periphery. The periphery of the chamber isprovided by a plate 66, and fluid pressure headers 23c and 2-3ee are provided respectively below the outer portion of the plate 20c and above the outer portion of the plate Zle, which plates are bored at angularly spaced points to provide openings 25c and 25cc respectively.

The openings 25c and 25cc are so directed that they point generally forward in a direction of rotation within the chamber. They also point transversely to the direction of rotation, but in the present instance, instead of pointing inwardly, point upwardly and downwardly respectively, as well as forwardly, the direction of the streams passing through these openings being indicated by the arrows E and F. As will be noted, the openings are so disposed and the streams so directed that the streams will cross each other, so that particles moving in the direction of oppositely disposed streams will impinge upon each other with a great increase in pulverizing effect.

chamber 22a is fed through a plurality of unilector member 362 and a conduit 39e arelikewise provided. j

In an apparatus constructed and proportioned as shown in Figs. 9'and 10, .thedialmeter of-the chamber He may, for example, be 14" and the height 1%". The jet openings may be positioned A,," from the periphery and may be /8" in diameter, if four jet openings are provided at both top and bottom. The injector opening may be A,", the Venturi opening and, the supply opening 1%". Sixteen of these feed openings may be provided.

As above indicated, the invention is capable of embodiment in a wide variety of types of methods and apparatus a number of which are illustrated diagrammatically by and in Figs. 11-32.

In Figs. 11 and 12 fluid is injected into the chamber 22f from a header through jet openings illustrated diagrammatically at 23 and 25] respectively, and the walls 20 and 2!) diverge from the periphery of the chamber inwardly, the wall 2U diverging rapidly at an inward point as inrangement of the type shown in Figs. 9 and 10,

except that the coamal collector is omitted, since I plate without substantially affecting the operation, except possibly in instances where the radial distance of the plate outw'ardly of the outlet opening is particularly small. It is to be noted that in the present exempliflcation, the plate 2 lh extends directly radially inwardly and the conduit 39h does not extend interiorly of this plate.

In Figs. 17 and 18, there is shown a similar arrangement, except that the walls 201'. and 2| i converge inwardly so as to increase the entrainment component of the vortex in certain instances, as where a relatively uniform product which is coarser than would otherwise be obtained, is desired.

In Figs. 19-and 20, there is shown an arrangement of the type shown in Figs. 9 and 10, except that no upwardly directed jets are provided, and that the upper wall slants upwardly.

In Fig. 21, there is shown an exceedingly simple arrangement similar to the construction of Fig. 14, except that the jets are directed forwardly and inwardly.

As will be apparent, it is not of importance that the jets all be in the same plane or all have the same direction, and in Figs. 22 and 23 show an arrangement wherein the four jet openings 251' are disposed in a diiferent plane and havin different forward and inward components. In this exemplification 'also no collector is provided, the outlet conduit 39f in this instance acting to carry 0115 both fluid and entrained particles.

Fig. 24 shows a similar arrangement embodying a collector member 36k and a conduit 39k.

As above indicated the jets may be directed forwardly and outwardly to give the very effective action which the invention makes possible, as well as forwardly and inwardly or forwardly and axially so long as the jets have a forward component of movement, a component of movement transverse to the lines of a vortical movement so that they will cut across it. In extreme instances, the efliciency of such arrangement might be reduced, butthere is shown in Fig. 25

an embodiment of the invention which gives satis factory results. Inthis instance,'the jet openings 25m give a direction to the jets which is forward in a direction oi rotary movement and transverse thereto in an obliquely outward direction. The peripheral wall of the chamber 22m slants upwardly and outwardly in this instance so that the particles which work centrifugally to the walls will be picked up by the streams and be given an active movement across the lines of vortical movement. The eddies set up by the streams will likewise tend to keep all the particles in active circulation. It is to be noted also that the upper wall 21m is extended axially for a short distance' at an inward point, and theninwardly, but that the vortical movement'and eddies formed thereby are suilicient to prevent undesirable concentration oi. material against the short axial portion of this-wall.

As above indicated, it is not necessary that all of the fluid be injected in streams having both forward and transverse components of movement,

noris it necessary that the withdrawal opening or openings include the axis of the vortex. In Fig. 26, there is shown an arrangement wherein a multiplicity of jet openings 2511. discharge streams of high velocity fluid 'from a header 23 11. at angularly spaced points, each of said streams having a component of movement which is forwardin the direction of rotation (clockwise looking component and a component which is counterclockwise (looking down on the figure). If, for

instance, the diameter of the jet openings 2511' is three times the diameter of the openings 10, the fluid entering through the openings 10 will v not be sufficient to diminish the whirling action of the vortex undesirably, in many instances, and

a will create an additional turbulence which is desirable in certain instances, as, for example, when material which compacts readily is being treated. Likewise, in this exemplification there is provided a withdrawal-opening 381:, which is in. the form of a curved slot disposed outwardly of and providing an entrance to a conduit 391: which extends outwardly and downwardly from the device.

While the provision of oppositely disposed outlet openings, such as 35 and 38, 35a and a, etc., is desirable, this is not essential for collection in accordance with the invention. For instance, an arrangement such as exemplified in Fig. 27 may be utilized. In this embodiment of the invention, an opening p leads from the vortex chamber 22p to a collector member 36p, which has disposed therein a duct ll adapted to receive fluid through an opening 12 at an inward point in the separating zone within the collector member, and

to carry it outwardly. The collector member in.

Figs. 3 and 4, it is not essential that all the material be kept in circulation in the vortex, so long as it does not gather at points where it would re-enter the vortex in undesired concentrations. Moreover, while it is desirable in most instances that the vortex be relatively unobstructed,,batlle means may be supplied in many instances "without unduly disturbing the operation, and in some instances with beneficial eifects. The embodiment of the invention illustrated in and by Fig. 28 involves an arrangement wherein material is permitted to work out from the vortex as through a conduit 13 leading from the vortex chamber 2 2g to a receptacle II wherein material is entrapped.

The entrapped material may be tested from time.

to time'to determine the condition of the operation, or may be otherwise utilized. Likewise, there is provided an annular opening 15 in the bottom wall 20q leading to a chamber 16 having an outlet conduit 11. Material, which is iairly fine but not so fine as to be entrained by the fluid entering the collector member 36:], will work into the chamber 16 and can be carried out through the conduit 11 without material interference with the vortical action. Such a procedure or a-construction may be desirable where the provision of material of two grades of average fineness, is desired. In the present instance also there are pro conduit 39s.

vided bafile means 18 and'19 extremely interior from the plates 20q and 2lq respectively, at the points indicated.

While the feedirg means is ordinarily disposed. outwardly of the withdrawal openings so as to insure against entrainment of the supplied material with the withdrawn fluid, it is only essential that the material be supplied at a position where the withdrawn fluid has no substantial entraining effect. A construction adapted for this purpose, but wherein the feeding means is nevertheless substantially axial, is exemplified in Fig. 29. Material is supplied to a central point, as through a tube 18 coaxial with the vortex 'and an opening 261" which is just above the center of the bottom plate 201' from feeding means 281*. The fluid iswithdrawn through an outlet opening 397" which is in the upper vplate Zlr and which is spaced a considerable distance from the opening 261-. The coarse material supplied will all be. thrown outwardly by the centrifugal action of thevortex before it has an opportunity to work upwardly to the outlet opening. Also under certain operating conditions (asfor example a low feed rate) the material may be fed into the chamber through tube 80 by gravity due to the suction at the-opening 26r which is disposed much further in than the periphery of the outlet opening 391".

As above indicated, the axis of a vortex formed in accordance. with ,the invention may in certain instances be other than vertical since gravity is an exceedingly small factor in the operation, where the circulating load is small. Even when the entrained particles are separated from they fluid in accordance with the invention, this remains true. In Fig. 30 there is exemplified an arrangement wherein the axis of the vortex formed by the use of the apparatus and in carrying out the invention is horizontal. The walls 208 and 2ls, in this instance, extend generally vertically, and the collector 36s and the conduit 39s extend generally horizontally. The constricted portion 31s of the collector opens into a bin 81. Theseparated particles work outwardly through the portion 378 due to the pressure dif ferential resulting from the slowing down of the vortex towards the right hand end of the collector, and the freed fluid escapes through the It is further to be noted in this connection, that while many of the plates 20, 2!, 20a, Zls, etc., are spoken of as lower and upper plates, that such positioning is merely the normal one in the exemplification shown, and that it is not essential that the collector be on the bottom or even on the side, or that the axis of the vortex be in any particular position whether or not a collector is used.

There are a number of cases where thorough classification of the material is" unessential, where the fresh material introduced-is already very fine, or where. for any other reason the classification step is not to be especially provided for. In such cases, results which are very satisfactory from many standpoints may be obtained, without thoroughly classifying the material. If desired also, particles which are not thoroughly classified may be separated from the fluid in accordance with the invention. An embodiment of the invention adapted for such situation is illustrated in and by Fig. 31 wherein the lower wall 281? extends inwardly from the periphery of the chamber 22t only a short distance, where it terminates in a withdrawal opening 35t. From the withdrawal opening acollector member 361. extends downwardly in the present instance.

There are many instances in which it is permissible or desirable to utilize streams having a relatively small transverse component of movement, and it is to be appreciated that the transverse component of the stream does not need to be as large as in the previous exempliflcations' in order to obtain an efiiciency of pulverization which is satisfactory in most instances. In Fig. 32 there is shown an arrangement wherein the jet openings 25a are arranged to discharge fluid from a header 2321. into a vortex chamber 22u in a. direction having a. relatively small,. but ample, transverse component of movement.

It is also to be appreciated that in instances where classification of the material is of outstanding importance and where efliciency of pulverization is of relatively less importance, (as

where a powder in which substantially all the particles are of exceedingly small size is desired regardless of the quantitative production obtained or of the wear characteristics, where the greater proportion of the material to be treated is already sufficiently fine, or where the material to be treated is very readily frangible) the small, high velocity stream or streams may be introduced, and the jet opening or openings arranged to discharge, in a direction which has no substantial transverse component, and-a qualitative- 1y excellent product obtained. In such instances the smaller pulverizing action to be had will be exerted (with a relatively light circulating load when relatively difiicultly frangible materials are being treated) without obtaining the full benefit of the invention from a pulverization standpoint, but the very high degree of classification made possible by the invention is obtained. Moreover the combination of classification and collection in accordance with the invention will be' unimpaired. It is accordingly to be understood that the invention in its broader aspects as applied to the provision of a highly classified product is not limited to the introduction of fluid in a direction having a transverse component of movement as above exemplified, or to the provision of 'jet opencedure and of means for classifying material by the introduction of a small quantity of high velocity fluid into the outer portion of an inwardly spiralling vortex which passes through a classification zone disposed substantially radially inwardly of said outer portion, whether or not the stream or streams have a substantial component of movement which is transverse to the direction of rotation. For example, in instances such as above indicated the jets of various of the showings, including those of Figs. 1- and 2, 5 and 6, 5a, 6b, and '7 and 8, may be tangentially directed, and certain new and useful results obtained in accordance with the invention. It is to be observed that in all the procedures and all the means exempified, with the exception of certain cases as discussed in connection with Fig. 31, classification is eiTect-ed in an axially-confined (narrow) zone which is continuous with the axially-confined outer portion of the chamber in substantially the same plane; and thefluid and entrained fine particles are withdrawn at the inner end of the classification zone, so that the withdrawn particles may be directly centrifugally collected as in Fig. 1, etc., carried off for collection as in Fig. 14, etc., or otherwise employed outside of the chamber.

- obtained at an expenditure of approximately 15 In order to give a general idea of operating conditions under which satisfactory results have been obtained in accordance with the invention, several typical procedures which have been successfully carried out are exemplified below.

Example 1 Steam at a pressure of 115 pounds per square inch and at a temperature of 450 F. was introduced into the header of a construction such as shown in Figs. 7 and 8. When a certain graphite substantially uniformly 5 mesh in size was supplied to the vortex at a given rate, a product having an average particle size of about 1 micron and a maximum particle size of about 3 microns was obtained at an expenditure of approximately 11 pounds of fluid per pound of product.

Example 2 Under the conditions of Example 1 when the same material was supplied to the vortex at an increased rate under conditions requiring an expediture of approximately 3.7 pounds of fluid per pound of product, a product having an average particle size of about 6 microns and a maximum particle size of about 10 microns was obtained. Example 3 Under the conditions of Examples 1 and 2 when steam at a pressure of 180 pounds per square inch and at a temperature of 710 F. was

I introduced into the header, a product having an average particle size of about 1 micronand a maximum particle size of about 2 /2 microns was obtained at an expenditure of approximately 10 pounds of fluid per pound of product.

Example 4 Steam at a pressure of 180 pounds per square inch'and at a temperature of 710 F. was introduced into the header of an apparatus of the general form illustrated in Figs. 5 and 6, having a vortex chamber I4" in peripheral diameter, 1%" high at the periphery and for about 2" inwardly thereof and 4 high, 2 /2" further inwardly and having a 5" collector opening and a 2" freed-fluid outlet and provided with a single row of 6 nozzles directed forwardly and inwardly delivering 710 pounds of steam per hour. When coarse graphite was fed to the vortex, a productv having an average particle size of about 5 mi-, crons and a maximum particle size of about 10 microns was obtained at an expenditure of approximately 10 pounds offluid per pound of product. v

Example 5 Air at atmospheric temperature and at a pressure of 55 pounds per square inch was introduced into the header of an arrangement as described in Example 4. When coarse graphite was introduced into the machine, a product having an average particle size of about 22 microns and a maximum particle size of about microns was obtained at an expenditure of approximately 15 pounds .of fluid per pound of product.

Example 6 When the pressure of Example 5 was increased topounds per/square inch, a product having an average particle size of about 6 microns and a maximum particle size of about 12 microns was pounds of fluid per pound of product.

- Example 7 Steam at a pressure of pounds per square inch and at a temperature of 675 F. was introduced into the headerof an apparatus such as shown in Figs. 1 and 2. When a fairly heavy, easily frangible, coarse material of uniform 50,

mesh size was supplied through the feeding means, a product 97% less than 5 microns was obtained at an expenditure of approximately 3.7 pounds of fluid per pound of product.

Example 8 Under the same conditions of Example '7, except that the axial height of the vortex chamber was 1" less throughout, utilizing the same material, a product having an average particle size of about 8 to 10 microns was obtained at an ex-' penditure of approximately 4% pounds of fluid per pound of product.

Example 9 Steam at a pressure of 140 pounds per square inch and at a temperature of 700 F. was introduced into the header 'of an apparatus such as shown in Figs. 1 and 2. When coarse barytes screened through mesh was supplied to the vortex through the feeding means, a product having an average particle size of about 10 microns was obtained at an'expenditure of approximately 2.5 pounds of fluid per pound of product.

Example 10 Air at atmospheric temperature and at a pressure of 40 pounds per square inch was introduced into the header of an apparatus such as shown in Figs. 5 and 6. ,When coarse limestone screened through A mesh was supplied to the vortex through the feeding means, a a product having an average particle size of about 25 microns was obtained at an expenditure of approximately 6 pounds of fluid per pound of product.

Example 11 Air at atmospheric temperature and at a pres-.

sure of 110 pounds per square inch was introduced into the header of an apparatus of the general form exemplified in Figs. '7 and 8 having a vortex chamber, the periphery of which had a diameter of 18", a height of 2" at the periphery,

a height of 5" near the collector opening,'a col- Example 12 Air at atmospheric temperature and a pressure of 100 pounds per square inch was introduced into the header of an apparatus such as shown in Figs. 9 and 10. When, talc of the order of 200 mesh was fed into the vortex, a product having an average particle size of about 15 microns was obtained at an expenditure of approximately 4 pounds of fluid per pound of product.

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