US1978802A - Centrifugal classifying apparatus - Google Patents

Description

Oct. 30, 1934. M. A. I rssMAN CENTRIFUGAL CLASSIFYING APPARATUS Filed March 22, 1952 5 Sheets-Sheet l 4 5 li i Rm u 0 ,a x Ong. wa. 5.5 d d f mb. m UJI; WM`wm i/ 1m A /ll/ 1 4 JM O m Q Z Oct; 30, 1934.

M. A. LISSMAN CENTRIFUGAL CLASSIFYING APPARATUS Filed March 22, 1932 5 Sheets-Sheet 3 INVENTOR. MARCELA, L/ssMAN BY /Vza/Q/V/v Oct. 30, 1934.

M. A. LISSMAN CENTRIFUGAL CLASSIFYING APPARATUS Filed March 22, 1932 5 Sheets-Sheet 4 39 il l ffy, /5

i /oz /0/ i* n C INVENTOR. MAPCEL A. LISSMAN BYP/zzr/m ATTORNEYS.

Oct. 30, 1934. M. A. LlssMAN CENTRIFUGAL CLASSIFYING APPARATUS Filed March 22, 1932 5 sreets-sneet 5 INVENTOR MAQCEL A. LlssM/:N By #w/8% A @QAM w. fduj ATTORNEYS sections showing further modifications Patentedr 0er. 3o, 1934 1,978,802 CENTRIFUGAL CLASSIFYING APPARATUS Marcel A. VLissman, Alhambra, Calif., assignor to International Precipitation Company,

Los

Angeles, Calif., a corporation vof vCalifornia Application March 22, 1932, Serial No. 600,425

12 Claims. (Cl. 209--144) 'v This invention relates to apparatus for selectively separating suspended material from gases by centrifugal action,- and the mainv object of the invention is .to provide apparatus of this character' which will separate suspended materialfromgases and at the same time separately collect portions of such material of different neness so that the apparatus serves both.

vas a separator and as a classifier for the separated material.

Other objects of the. invention will appearA hereinafter.

The accompanying drawings illustrate embodiments of my invention, and -referring thereto:

Fig. l is a vertical-section partly in elevation of one form of the invention.

Fig. 2 is an enlarged vertical section of the upper part of the construction shown in Fig. 1. Fig. 3 is a horizontal section on line 3-3 in Fig. 2.

Fig. 4 is a horizontal section on line 4-4 in Fig. 2.

Fig. 5 is a horizontal section on line 5-'5 in Fig. 2. f

Fig. 6 is a partial vertical section showing a modication of the parts in the separating zone.' Figs. 7 to 11 inclusive, are partial vertical of such parts. I

Fig. 12 is a. side elevation partly in section of amodication of the invention provided with external means for propelling the gas and with meansh for feeding suspended material to the gas stream in case the apparatus is used solely as a classiiier, and also' with auxiliary vcollecting means for separating the most iinelydivided I which the whirling motion of the air or gas is effected by deflecting vanes. Y

Fig. 16 is a section on line 16-'16 in Fig. 15. Fig. 17 is a section on line 17'-1'7 in Fig. l5. 18 is 'a section on line 18-18 in Fig. 15. The apparatus shown in Figs. 1 to 5 comprises a circular casing l preferably formed` as a. vertical cylinder connected atl its open upper end to an inlet chamber 2 into which leads an inlet pipe 3, said chamber 2 .being provided 'with an involute or spiral wall vportion 2' as shown in Fig. 4l to direct the gasI tangentially into the upper portion of the cyclone chamber 1. A tubular outlet member 4 extends downwardly within the casing 1 and coaxially therewith, said member being formed, for example,

as a vertical cylindrical tube opening at its upper end into an outlet chamber 5 communicating with an outlet 6, said chamber 5 being preferably formed as shown in Fig. 3 with an involute or spiral wall portion 5 leading to said outlet 6. A partition plate 22 separates the inlet and outlet chambers but is provided with a central opening 4' establishing communication between the interior of outlet tube 4 and outlet chamber 5. A centrifugal fan or -impeller 'I is mounted within the chamber 5, being carried by the shaft 8 of a suitable motor, such as electric motor 9, which is provided with usual or suitable energizing and controlling connections, not shown, soV as to operate the centrifugal fan at suitable speed and in a directiony such as to force the gas toward the outlet s, the '15 spiral or involute wall of said chamber 5 enabling the outlet portion of said chamber to serve as a diffuser.

A tubular deflector 10 extends concentrically within the casing 1V and around the outlet member- 4 so as to dene between the casing 1 and the memberl an annular passage 11 whose radial width is small compared to the radius of the casing l, the said member 10 preferably nenngdownwerdw se that the radial width ef said passage 11 decreases progressively in a downward direction, said passage 11 terminating at its lower end in a comparatively narrow annular throat 1l. 'Ihe inner tubular return member 4 is shown as connected to the defiector 90 member' l0 by transverse webs 13, it being understood that the space between these inner and outer4 tubular members is substantially a dead space, being c'losed at its upper end by partition 22, and it is immaterial whether or not these webs be used.

A fines collecting chamber is mounted concentrically within the chamber 1 and consists of a vertical cylinder or separator. member 12 of somewhat smaller diameterthan the lower end of the member 10, said member 12 being mounted with its open upper end l2' at about the same level as the lower end 10 of the member 10 but preferably slightly below said level.

The eutlet member 4 extends downwardly to 105 aboutA e level of the upper end of member 12 and pre erably somewhat below said level.- Collecting chamber 12 is formed with a funnel 14 at its lower portion and with a second funnel 15 below the funnel-14 and opening at its lower end 11 chutes 16 and 19 communicate with'discharge gates' 420 and 21 respectively, located in suitable housings 20 and 21', whereby the collected material-may be removed continuously or from time to time as may be desired. Said discharge gates are'shown as weighted, so as to open and discharge the collected material on accumulation thereof in the chutes, but any suitable form of discharge gates, 'or other material-removing means may be used.

-Directlyfbelow the throat 11' aforesaid, is arranged a deflecting means 23 preferably formed with one or more horizontal dee'cting flanges 24.' In the form shown in Figs. 1 and 2, the

'member 23 is-'formed asl a frusto-conical member which tapers downwardly and the flanges 24A extending inwardlyI from said member' are' formed as annular vhorizontal flanges, the internal diameter of said annular fiangesdecreasing in descending order. Said member 23 [is shown as carried by a cylindrical supporting member 25, which is mounted to slide within the cyclone casing 1 and is provided with means for holding it at any desired vertical position. For this purpose screws 27 may be provided, working in nuts 28 mounted in fixed position on the casing 1 and rotatably engaging with a horiz tal flange 29 on member 23, so 'as to raise or lower said member upon rotation of said screws. Suitable openings may be provided inthe casing 1 enabling access to squared portions 31 on screws 27 for adjustment thereof, said openings being `normally closed by doors 32. The horizontaljflange 29 is preferably extended inwardly across theannular passage 34 between the cylinder'1'2 and the outer casing l and may be connected to the lower endof deecting member 23.- Said flange isl provided with openings 35 vthrough which lseparated material may descend in said passage, 'a vertical upwardly extending sleeve 36 being preferably provided at the inner edge of the horizontal ange 29 and. having 'at' its upper end an outwardly extending horizontal flange 37 which projects over the openings 35 but is spaced 'from member 23,- -The vertical sleeve 36 slides closely on the cylinder 12 inl-the verticall movement of member 23.

' pipe 3 to the -inlet chamber 2 and the impeller.

7 isset in rapid rotation to induce a draft through `the apparatus which causes the gas to be drawn through the inlet chamber 2 and dellvered intothe upper part of the passage` 11j with a high tangential. velocity,fre'sulting in a' whirling movement of,the gas combined with a' downward component of 'motion so that the gas eventually issues at the contracted throat 11' with a vortical movement and then passes under-thelower edge -10 of member 10 and over the upper edge 12j of cylinder 12 and under the 7G' lower edge ot outlet member 4 and upwardly through said outlet member to the fan or impeller chamber 5. In .said chamber the ali'. or

' ses which 'is sau whirling with a consideraba tnngbitialvclccity .ls brought in contact ywith the linner portions of the blades of the impeller which-are moving at about thesame tangential velocity and by the operation of the impeller and the involute casing 5 thereof, the air or gas is forced outwardly by centrifugal action and delivered at the outlet 6. The gas being treated is assumed to carry suspended material of different'degrees of fineness and such suspended material is selectively separated in the above-described operation in the following manner.

As the gas carrying'the suspended material passes downwardly within the annular passage 11 with a high tangential component of velocity the suspended material, especially the coarser particles thereof, is thrown outwardly toward the//wall of casing 1 so that is descends along this operation the gas passes inwardly aswell as upwardly and the coarser materialsl are held outwardly by the action of centrifugal force due to the rapid whirling movement so that the heavier particles accumulate and spill over the flanges 24and are eventually discharged through the openings 35 into the passage 34 and into the material discharge means communicating therewith. The fianges 24 and 37 serve to trap the separated suspended material and prevent it from being picked up and carried forward by the gas stream. The air or gas s'till possesses suliicient vortical motion when it passes over .the upper edge vof separator 12 to cause it to pass downwardly to a considerablev depth within said separator, while also passingl gradually inwardly and then upwardly therein to the outlet tube 4. The arrows in Fig. 1 represent only the components of this gas circulation in the plane of the drawing, Without any attempt to indicate the rotational component which also' persists throughout such circulation.

. In this operation the horizontally extending lip or flange 37 over the openings 35 tends to prevent the heavier particles from being drawn j' back by entraining action of the gas current.

-The separation of the coarser particles as the gas passes under the lower edge of the member 10 effected mainly by the centrifugal action on such particles due to their high vortical 13a;

velocity tending to hold them voutwardly toward the wall of casing 1, `while the gas is forced in'-y wardly by the suction from the impeller means and by the action of the deflector means 23; secondly, by the inertia or momentum of the coarser particles which tends to maintain their downward component of motion and thereby separate them from the gas stream which is defiected inwardly and upwardly by the defiector means 23 and 24 and separator means 12; and thirdly, by the action of gravity which tends to cause the coarser heavier i particles to spill' over the flanges 24 and through the outlets 35 as aforesaid. The throat 11 and the zone of classification indicated at 40 between the members 10, 23 and 12, are of small transverse dimensions as compared to the diameter of the casing, and also as comparedwith the diameter ,of the members 10 and -12,jso\tliat a sufficiently throat 11 and in said separating and classifying zone to insure that the fines will be carried forward by the gas stream and the coarse particles will be forced out of the `gas stream as above' described.

The gas passes from the classifying zone under the lower edge and into the cylindrical separator member 12, wherein it is subjected to a 'separating action by cyclonic or vortical motion,

greateror less extent, the relatively clean gas thence passing upwardly through the outlet tube L The lseparating operation in the separatorV AInriember 12is eected by the centrifugal action of the rapidly whirling gas within said member, it being understood that the gas enters the upper end of said separator member with a high tangential velocity ltogether with a downward component of motion. This results in a pressure head representing an excess of pressure at the peripheral portion or zone of the vertically mov vgas reaches the tapered outlet cone or funnel fied is still further improved by the horizontal 14 at the bottom of said member, the radial pressure head thereon is sufficiently vdecreased to enable the longitudinal pressure head originally imposed upon'the gas to force the gas inwardly as it descends in the outlet cone 14. 'Ihe proportions of the parts are preferably such that the pressure 4at the periphery of the outlet opening 14 at the bottom of cone or funnel 14 is somewhatv greater than the pressure in the lower outlet cone or funnel 15, so that there is a positive ejectingaction on the suspended particles. at the peripheral. portion of the outlet opening, it being understood that due to the vortical motion thesuspended particles, being heavier than the gas, arefthrown outwardly into the peripheral zone adjacent the' wall of the separatingrunit and descend along or adjacent such wall 'until they reach ,the outlet opening 14'. Concurrently with the' above-described operation, there is an' inward flow of relatively clean gas toward the center of the separating member and upwardk] to the outletv tube 4,- and thestream of relatively clean gas passes upwardly through the said outlet tube.

It will be observed that both the.relatively coarse particles separated `fro`m' the gas in 'the classifying zone and the relatively fine particles *separated in the separator 12 are removed from the gas before it reaches the impeller,'s'o that only a very small proportion of the solid particles are necessarily extremely' fine or light.

For this reason, the wear on the irpeller blades j is substantially eliminated or reduced to a min.

4imum, and this feature is of particular importance in'view of the high speed at which, the

\quantity of solids, Aand particularly the coarser solids, were permitted tocontact -the impeller'A`4 blades moving at Athis high velocity,- such blades would be worn away very rapidly.

By' keeping the annular-space 11 between the external cylindrical casing 1 'and tthe deflector .means 10 of small radial depth, the rate vof kept very. high.v Asa result, there is a zone imof velocity radially inwards is kept suillciently high to carry along the particles which are of causingthe fines to be separated therefromto a' coarse cut. I

vof the classifying zone 40 adjacent the lower end irnpeller is operated, for if any appreciable shear in the gas stream atthe outside wall is mediatelydjabent' the wan of reflector means 10, in which energy is dissipated at a high rate,

smaller diameter than those desired in the By keeping the tangential component of velocity in the classifying zone high, the particles are subjected to a high radial acceleration, many times that of gravity. This permits the inward component of velocity at the zone of classification 40 to be increased many times over that possible with low velocity classifiers. l This results in a unit which is very compact for the tonnage which can be handled, as the weight of material which can be kept in Suspension. in a gas stream increases rapidly with increasing velocity, and while the energy required to handle a unit volumeof gas at the higher velocity is increased, the weight of material classified per unit volume also increases. AThe dispersion of the material to be-classiflanges 24, which force the material away from lche external wall towards the more active zones of gas circulation, enhancing the chance of the fines being picked up and'carried along by the main gas stream..

-While the design is such as to create strong eddies in the dispersion zone adjacent the outer walls, sufficient tangential component of velocity remains to obtain smooth stream lines of flow in the classiiication zone, without major eddies. The inertia of the larger particles makes them move downwardly'away from edge 10' of the deector 10, due to the downward component of velocity in the annular space between l and l0. .'I'he'separation or classification zone `i0 is so proportioned that the larger particles which it is desired to separateican not reach the edge lll `10', but are thrown again into the descending f ensure that an `oversized particle will be forcibly ejected out of .the inner vortex moving towards the gas outlet of the classifying zone, before edge 12" is reached, and all such oversize particles eventually spill over the flange means 24 and pass through openings 35 and to the coarse material outlet means 19. Y

ABy'reason of the fact that the circumference of the tubular deflector member 10 is approximately the maximum circumference of the apparatus, a comparatively large total cross-section. of such zone with accompanyingly large operating capacity is secured, while at the same time f the .narrow transverse dimension of such zone between said lower edge and the deilector means 23 and 12 provides the high velocity and sharp curvatureof motion which produces the close classifying effect desired. 15

If desired, provision may be made for adjustment of any of the deflecting means ab'ove described in addition to or alternatively with `adjustment of the flange means which extend which is mounted coaxially within the outer casing 41 and within the tubular deflector flange 42', may be provided with a downward extension 45 adjustably mounted thereon by bolt and slot connections 46, so as to adjust the lower edge 45 of the member 45 upwardly or downwardly to give optimum separating conditions. Similarly, the inner lower partition cylinder 47,

which is mounted within the outer casing 41- below the tubular deilector means`42, may be provided with an adjustable extension 48 mounted thereon by bolt and slot connections 49 providing for vertical adjustment of the member 48 to bring its upper edge 48 to the most effective position. 'I'he flange means 50 extending inwardly from the outer casing 41, is also shown as mounted by bolt and slot connections 51 to provide for vertical adjustment of same. In this form ofv the inventionsaid flange means is shown as provided with fa plurality of horizontal flanges 52 and with passage means 53 between the lowermost flange means 52 and the inner cylinder 47 f or passage of coarse material into the space 54 between -the members 41 and 47. In other respects the construction and operation of this form of the invention may be the same as above described.

As shown in Fig. 7, the deflector flange means may consist simply of a horizontal flange 55 extending inwardly from the outer casing 56 to the inner lower partition cylinder 57, opening means 55', being provided near the inner edge of said flange t permit passage of coarse material therethrough'. Said flange means may 'be provided with an upwardly extending sleeve 58 fitting closely around cylinder 5,7 and having an outwardly extending flange 58.located over the openings 55 and serving to deflect the gas upwardly and the coarse material downwardly toward the openings 55. Theconstruction of this form of apparatus may be otherwise similar to that above `described and the operation is also similar, .it being understood that yin practice more or less coarse materialv will generally accumulate on the flange 55* in a layer whose slopev corresponds to the angle of repose offthe coarse material under the conditions present. The upper deflector tube and outlet tube are shown at 10 and 4 respectively. l

As shown in Fig. 8, an apron 60 may extend downwardly and outwardly from the lowerpartitioncylinder`61 adjacent a coarse material outlet passage means 62-between said cylinder and the horizontal deflector flange`v 63 which extends inwardly from the outer casing 64, this apron permitting descent of coarse material but tending to obstruct thereturn of coarse material through said passage means.

The deflector flange means extending inwardly from the outer casing inthe forms of the invention above. described, operrates as ar trap for selectively removing the coarse particles from a gas stream and allowing such particles to fall into the coarse material discharge means. Any

suitable flange means may be used for thisfpurinner flange 68'extending outwardly from the flange 66 and spaced therefrom toform a discharge opening 70 for ycoarse material. In Fig. 9 the discharge outlet 70 is near the wall of the outer casing, the flange 66 being relatively narrow and the flange 68 being relatively wide, but if desired the discharge outlet for coarse material may be located near the inner member as shown in Fig. 10,.the upper flange 71 extending from the outer casing 72 nearly to the inner partition cylinder 73 leaving a discharge opening 74 between said parts, and thelower flange 75 is relatively narrow and extends from the inner member 73 directly under thel discharge outlet 74. f

It is preferred to so construct the apparatus that the annular passage between the outer casing and the tubular deflector decreases in radial dimension toward the bottom, so as to produce maximum peed at ythe throat where the gases leave suchY annular passage and enter the classifying zone. In the form shownin Fig. 1, this effect is secured by increasing the diameter of the tubular member 10 toward its- `lower end, but as shown in Fig. 11, the same effect may bev secured by decreasing the diameter/ of the outer casing 78 from the inlet chamber 2 to the bottom of Ithe tubular deflector means 79. As illustrated in this figure, horizontal flanges or baliles 80 may also be provided within said annular passage, said horizontal flanges extending inwardly from the wall of casing 78 and forming obstructions which force the gas and the material `carried thereby momentarily away from the wall of said casing, thereby producing eddies which aid in knocking of the finer particles which tend to adhere to the coarse particles. Also, as illustrated in this figure, the flange member indicated at 84 may be formed as a plain cone without horizontal flanges, the construction and mounting of suchl above ciated therewith may extend horizontally or at any desired inclination, modiflcations being made where necessary in the discharging means for the divided material, it being'understood that .the gravitative action-:is small compared to the' centrifugal forces-exerted as above described,

and the classifying and'separating operations .will be effective irrespective of the angular posi-r tion of the apparatus. It will be further understood that the components of motion which tend to move the suspended material, either coarse or fine as the case may be, toward the dischargeor 'outlet `,means therefor, are not necessarily vertical, but, in any case, such components areY longitudinal or parallel to the axis of the apparatus, as distinguished from the tangential comin advance of the classifier or`behind the classi-1 ier. Thus, as shown in Fig, 12, the blower indicated at 364 may be connected to the inlet chamber 87 of the classier 88 so as to force the air or gas tangentially into said chamber with suific'ient velocity and pressure to effect the separating operation as above described. Said fan or blower 86 is operated by a suitable motor 89 and has its inlet 90 connected to suitable means for supplying the gas to be treated. In case it is desired `to'also collect the extremely fine material which passes through the classifier without collection, the outlet pipe 92 leading from the outlet chamber 93 of the classifier 88 may be connected to suitable co1- lecting means of any suitable type, for. example, as shown in` Fig. 12, to a cyclonic separator 94 having its tangential inlets 95 connected to the pipev 92 and having its central out1ets 96 connected to an outlet header 97. Said collecting apparatus 94 is shown as comprising a plurality of separator tubes having tangential inlets connected to the pipe 92 as above described and being provided at their lower ends with constricted outletsl 98 for dischargingi collected material to suitable receiving m ans 99.

While the apparatus is specially designed and adapted for separation of material from a gas stream containing suspended material of different grades of neness, it may also be used to advantage as an ordinary classifier, thelfinely Idivided solid material being in that case fed by suitable means indicated at 100 to the inlet pipe 90r for the blower" 86, and being carried /forward and distributed in the gas stream by the entraining action of the air or gas current and by the agitation of the fan or blower 86. In this application of the invention the apparatus may operate on closed circuit, the inlet pipe nected directly to the outlet header 97 for the separator or collector 94. The construction of the classifier 88 in this form of the invention may be similar to that above described in connection withFig. 1, and said classifier operates to separate and collect the coarse material in the delivery-means 101, and the intermediate material in the delivery means 102, the extreme fines being separated in the separator 94 and collected in the delivery means 99 aforesaid.

In the form of the invention shown in Figs. 15 to 18,4 the whirling movementof the air or gas is produced by deecting varies. V The inlet 106 for the vgas enters non-tangentially into the inlet chamber 107 at the upper part of the cylindrical classifier casing 105, and the deflecting vanes 110 are formed as helical segments mounted on a downwardly Haring extension 109 of an inner deiiector member 108, so as to impart a tangential component of motion to the gas or air passingdownwardly from the inlet chamber 107 to the contracted throat or passage between `the lowerv end of ythe member 109 and casing 105. n outlet pipe 112.' extends coaxially with casing 105 and inside thev members 108 and 109, and opens at its lower end into ther interior of said casing and at its yupper end into an outlet chamber 113 provided with a tangential out- 'Vlet 114. An impeller or fan 115is mounted within the ychamber 11.13 and driven by motor 116 so as to induce a draft through the appara- 4tus in the manner above described.

Deector means'l17 provided, if desired, with anges 118 is mounted below the lower end of fthe denector means 109 and is provided with openings 119 permitting passage ofseparated 90 for the blower 86 beingbfor example, con' ytion through said outlet tube, and outlet means material into the space between the casing 105 and an inner cylindrical separator member 120, this space discharging coarse material into delivery means 123 and the space within the separator member 120 delivering discharging fines to the delivery means 124.

f The means for adjusting the deector means 117 is shown in this case as comprising adjusting screws 121 rotatably connected to the member 117 and extending through the funnelshaped bottom of the casing 105V andprovided at the lower ends thereof with operating han--y dles 122.

The operation of this form of my invention is similax` to that above described, except that the tangential or whirling movement is imparted to the air or gas by the spiral or helical vanes instead of by a tangentially entering stream of gas.

I claim: i

1. A classifying apparatus comprising a cylindrical casing provided at one end with an inner tubular deflector member and at the other end with a cylindrical separator member mounted coaxially withinsaid casing, a central outlet tu/be extending coaxially within said casing and within said tubular deector means, means for supplying gases carrying suspended material to the space between said casing and said tubular deflector member and @or imparting whirling movement vto said gases, deilecting flange means extending inwardly'from the cyedge portions adjacent to one another and to said deflecting flange means to cause the gas discharged from the passage between the casing and the tubular dei-lector member to be de- 1.15 ected flrst between the edges of the tubular deflector member and the separator member, then longitudinally within said separator member, and then reversely in a longitudinal direcconnected to said outlet tube.

2. An apparatus as set forth in claim 1, in which said outlet means comprises an outlet chamber, a rotary fan mounted in said chamber, and means for operating said-fan to induce flow 125W of gas from said inlet through the said apparatus and the outlet tube thereof.

3. A classifying apparatus' comprising a cylindrical casing, a tubular deilector member extending downwardly from the upper end of said casing and coaxially therein and of less diameter than said casing; means for supplying. gas containing suspended material downwardly with a. whirling motionwithin the space between said casing and said tubular deilector member, a cyl1:35 lindrical 'separating member open at its upper end Aand mounted coaxially Within the lower portion of said cylindrical casing and of less diameter than said tubular deflector member, said separating member having its upper edge at a level adjacent the lower edge of said tubular deflector member but spaced therefrom so as to provide-for inwand passage of gas between the lower edge of ksaid deflector member and the upper edge of said 'separating member, the space 145 between said casing and said separating member communicating at its upper end with the space' between said casing and said deector member so as to receive lmaterial separated from the gas outwardly of said separating member, and the space within said separating member serving to receivematerial separated from the gas inwardly the upper portion of said casing and communieating at its lower end with the space within said separating member.

v 4. An apparatus as set forth in claim 3, and also comprising deflecting ange means project- -ing inwardly from said casing below said tubular deector member and around said separating member and providing an opening positioned inwardly froml said casing for passage of separated material into the space between the casing and theiseparating member and below said flange means t 5. A classifying apparatus as set forth in claim 3, and comprising, in addition, annular deflecting flange Ameans projecting inwardly from said casing below said tubular deector member and around said separating member and providing an opening positioned inwardly from said casing' for passage of separated material into the space between the casing and the separatingmember and below said flange means, and means for vertical adjustment of said annular deflecting iiange means to vary its position relative to the lower edge of the tubular deflector member.

6. A classifying apparatus comprising' a circular casing, a tubular deflector member extending downwardly within said casing' and concentrically thereof, means for delivering gas downwardly with a whirling motion in the annular` space between said casing and deiiector member, a tubular separating member disposed concentrically within said casing below said deector member and of less diameter than said deflector member, an outlet tube disposed concentrically within said deector member and of less diameter than said separating member, gas outlet means connected to said outlet tube, and separate material collecting me'ans connected to the interior of said separating member and to the annular space between said separating member and said casing.

7. An apparatus as set forth in claim 6 and comprising, in addition, defiecting flange means projecting inwardly from said casing below said deector member and around said separating member, opening means being provided for passage of material downwardly between said flange means and said separating member andintosaid annular space' between the separating member .and the casing.

adjacent that of the upper edge of saidtubular separating member.

9. An apparatus as set forth in claim 6, and

comprising, in addition, deflecting flange meansA projecting inwardly from said casing below said -deector member and around vsaid separating member and providing opening means for passage'of material downwardly into said annular space between `the separating member and the casing, and means for vertical adjustment of said` deiiecting flange means to vary Vits position relative to the lower edge of said tubular deflector member.

10. In a classifying apparatus, a vertically elongated substantially cylindrical casing, a vertically elongated substantially cylindrical separating member disposed substantially concentricaiy within the lower portion of said casing, said separating member being open fat its upper end and of somewhat less diameter than said casing. means for delivering gas containing suspended material downwardly with a whirling motion acacent the wall of said Acasing at a position above the upper edge of said separating member, deiiecting flange means projecting inwardly from said casing around said separating member at a position adjacent the upper inner edge spaced from said separating member so as to provide an opening for passage of separated material downwardly between said flange means and'said separating member, a gas outlet tube disposed concentrically within the upper portion of said casing and of less diameter than said separating member and communicating at its lower end with `the space within said ,separating member, material discharge means connected to the space between said separating member and said casingbelow said deiiecting flange means, and separate material discharge means connected to the space within said separating member.

11. In a classifying apparatus, the combination as set forth in claim 10, said deecting flange means comprising a plurality of inwardly projecting flange members disposed at progressively lower'levels and of progressively decreasing internal diameter.

12. In a classifying apparatus, the combination as set forth in claim l0 and also comprising 'means for vertical ladjustment of said deecting ange means to vary the position thereof with relation to the upper edge of said separating member. v

MARCEL A. LISSMAN.

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