US2138810A - Hydraulic sizer - Google Patents

Description

Nov. 29, 1938. c. E. wooD HYDRAULIC SIZER 6 Sheets-Sheet 1 Fi'led Feb. l5, 1936 Nov 29, 1938.. c; E WQOD 2,138,810v

HYDRAULI C S I ZER Filed Feb. l5, 1936 6 SheetS--Sheet 2 C. E. WOOD HYDRAULIC sIZER N081.V 29, 193s.

Filed Feb. 15, 195e e sheets-sheet 3 Nov. 29,1938. c. woon HYDRAUL IC S I ZER 6 Sheets-Sheet 4 Filed Feb. l5, 1956 Nov. 29, 193s.

HYDRAULI C S I ZER c. E. w'ooD 2,138,810

Filed Feb. l5, 1956 6 Sheets-,Sheet 5 Nov. 29, 193.8. C; E, WOOD 2,138,810

HYDRAULI C S I ZER Filed Feb. l5, 1936 6 Sheets-Sheet 6 Edy/0 Patented Nov. 29, 1938 UNITED STATES PATENT OFFICE -14 Claims.

My invention relates to a sizing, screening or classifying means and has for one purpose the provision of means for separating a mixed mass of particles by size, with the isolation of the larger from the smaller particles. Another object is the provision of a separating medium and means for preventing its apertures from blinding. Another object is the provision of means for separating articles by size, in connection with the employment of liquid or gaseous means for preventing blinding of the bed. Another object is the provision of improved means for feeding material for separation or sizing. Another object is the provision of impro-ved means for taking off the oversize. Other objects will appear from time to time in the course of the specification and claims.

I illustrate my invention more or less diagrammatically in the accompanying drawings, where- Figure 1 is a plan view;

Figure 2 is a. side elevation;

Figure 3 is a vertical axial section, taken on line 3 3 of Figure 2;

Figure 4 is a section on the line 4 4 of Figure 3;

Figure 5 is' a section on the line 5 5 of Figure 4;

Figure 6 is an enlarged section on the line 6 6 of Figure 4;

Figure 7 is a plan View on an enlarged scale, with parts broken away, illustrating the top of the separating or sizing bed;

Figure 8 is a. section on the line 8 8 of Figure 7;

Figure 9 is a perspective of a variant form of the device;

Figure 10 is a vertical longitudinal section on the line ID-I 0 of Figure 9;

Figure 11 is a sectional view similar to FigureV i0 of a further variant form; and

Figure l2 is a fragmentary section illustrating a variant form of water inlets.

Like parts are indicated by like symbols throughout the specification and drawings.

Referring to the drawings, I indicates any suitable foundation upon which the device is mounted. 2 indicates any suitable base structure, for example of channel iron, which may be bolted or otherwise secured to the foundation. 3 indicates opstanding structural members for supporting the device which may be connected., for example, by cross pieces or angles 4. Preferably I employ four of the supports 3 arranged on a. base 2 which is shown as rectangular. This structure will be clear from Figure 1 and the members 4 may be conveniently formed of angle irons. The members above described may, for example, be welded together.

Mounted upon the upper end of the members -3 is a channel or ring structure generally indi- 5 cated as 5 which is shown as having a botto-rn 6,

an inner cylindrical Wall l, and an outer cylindrical wall 8. At one or more points', and I have shown only one, is an aperture 9 having an outlet spout I0 communicating with any suitable 10 member such as a run off trough II. Mounted on the inner wall 'I is a channel I2, which may be welded thereto and extends circumferentially around the entire interior of the said wall. As shown, for example, in Figure 4, it is provided 15 with a plurality of holes I4 and the space between the channel I2 and the wall I forms a passage which may be: employed to admit a liquid or fluid. In order to permit its: admission I provide an inlet sleeve or flange I5 in communica.- 20 tion with any suitable fluid inlet pipe I6 shown in Figure 3 as passing through the walls of the member 5.

Below the channel I2 I illustrate a ring or flange I'I welded or otherwise tightly secured to 25 the inner face of the wall l. Clamped to it is a. rubber diaphragm or ring I8 which may be secured by any suitable clamping ring I9 and the clamping bolts 20. Secured in a similar manner by a ring I9a and bolts 20a to the inner edge of 30 the flexible diaphragm I8 is a plate, herein shown as a shallow funnel or hopper 2| although it will be realized that its shape may be widely varied.

l'. find it advantageous, however, to have it in the form of a funnel or cone converging upon a 35 central run-off passage member 22 which may be connected to an outletpipe or duct 23 as by the fitting 24. The outlet pipe 23 may be of any suitable substance and, if desired it may be of rubber or yielding material, or of metal. The 40 structure 2l may be supported, as upon concentric rings 25, 26, of metal or any other suitable material, it being understood that in the form herein shown the member or funnel 2I moves as a unit with its supporting rings. 25 and 26, which 45 may be welded thereto if desired. I illustrate also vertical plates 28 which may be welded or otherwise secured to the structure so formed. I illustrate two, diametrically opposed, as shown for example in Figures 4 and 6. Welded to the 50 bottoms of these plates, and to the rings are horizontal plates 29. Positioned beneath each such plate are pads o-f rubber 30, 3 I Between the two pads is positioned another block 32, as shown in detail in Figure 6. The assembly so formed is 55 clamped together by a bottom clamp member 33 held tothe hub plate 'E5 as by bolts 34 and spacer sleeves Mounted or otherwise secured to the blocks 32 are rods 35. Each such rod terminates in a bearing housing 31 to which it is adjustably secured as by the screwthreading 3S and the lock nut 38. Each such housing 31 encloses a ball or roller race It which has within a tapered sleeve il! surrounding an eccentric portion 43 of a rotated shaft 12. The bearing assembly is further enclosed by a. removable cover plate 44. The shaft i2 rotates in xed bearings d5 which are shown as secured to the base structure 2. Any suitable drive pulley 45 may be employed. Instead l5 of illustrating a unitary shaft I show twoshaft portions secured together by a hollowconnecting sleeve 131. It will be understood that any suitable drive may be employed whereby the pulley 4.5 and:

. ture is permitted by the rubber ring or diaphragm i8. It will be observed from Figure 5' that .there is a clearance between the up-per end of each rod and-the locking plate 33, there being an oversize aperture 33a through which the upper end of 30 each rod 38 passes. There is thus no binding and a slight lateral or angular movement is permitted, which is ample to take care of the movement of the device as a whole.

In order to limit any undesired tilting of the member 2I and its associated structure, on account of the rocking means of the rods 36 as they are oscillated by the rotation of the eccentrics 43,

I provide balancing or equalizing springs 58. I show one at each side ofthe device but more could Oibe employed if necessary. A practical arrangement, however, as shown in Figure 5, is to employ two springs 50, diametrically opposed, and midway between the rods 36. Each such springv 50 is mounted upon one of the angles 4. A- suitable bottom guide 5I may be employed as a retaining stud. Penetrating .the upper portion of the spring 58 is an upper guide 52 formed with ahexagonal spring abutmentwhich may be -adjustably bolted into a 4block 53, secured to vertical plates 54 which :.in turn are secured to the rings 25, 26 andto the member 2l. A lock nut 55- serves to lock the screwthreaded upper guide 52 in any desiredposition and thus permits adjustment of the-spring tension.

55:. It will thus beV observed that the space within the inner wall 1 is entirely closed by the hopper 2| and the connecting rubber ring or. diaphragm I8. The top is closed by a separating or sizing bed the details of which I will now describe. Resting upon the upper flange of the channel I2 is a spider structure shown as including a plurality of radially converging double spider arms 60. Each such arm consists of twin metallic members connected by blocks 6I. The arms are also welded to an outer ring 82 which in turn may be welded to the inner face of the wall 1. They are also shown as welded to an inner hub 63. If desired,

I may provide cross arms 64, as shown in Figure 4' Zontal. The bed itself includes a bottom foraminous plate or plates 65, a top plate 66, and a plurality of radial vertical partitions 61, and, if desired, additional concentric partitions 68. Thus the space between the upper and the lower foraminous plates is divided into a rather large number of separate cells or compartments. Filling each compartment is a mass of balls or similar small relatively movable particles indicated at 69. I illustrate them, as shown in Figure 8, as forming two levels or layers but a thickery or a thinner bed may be employed, depending upon the needs of a `particular situation or the characteristics of a Screwthreaded into the sleeves are securingy screws 1I, with heads 12 which, with washers 13 serve to hold ydown the upper plate and clamp the bed structure. Spacing sleeves 14are also employed, about the screws 1I, to space the upper and lower plates apart at the right-distance, to preventclamping action on the balls and to leave them enough play to permit themto perform the desired function andto allow enough movementto prevent their blinding. In other Words, a relative movement of the balls in relation to each other and to the plates is necessary, but it must be confined within a range suflicient to prevent undue variation in the size ofthe apertures between adjacent balls, as a reasonable uniformity is necessary to obtain accurate sizing.

Upwardly projecting from the hub 63 is a central stud 8U. Outwardly and upwardly extending from it are radial arms 8| `which are connected at their outer ends as by plates 82. These plates carry a circumferential ring 83. Clamped to the inner edge of thisring, as by clamping members 84, is a flexible inner ring 85. Clamped to the outer edge, as by the clamping members 86, is an outer and much more extended flexible ring or skirt 81 which may be of rubber or the like. It extends out to the extreme edge of the bed, preferably, and may be downwardly curved at its outer edge as at 88. The outer edge of the structure 81 may, if desired, rest upon the outer screw heads 12. Or, if desired, it might rest on the intermediate bolt members. However, the arrangement shown in Figure 8 is practical and satisfactory and a certain clearance for the material passing over the bed is desirable. If the material fills the space between the top of the bed and the member 81, its flexibility is sufficient to permit it to rise and givespace for the material.

In the form of my invention illustrated in Figurev 1 and following I show a structure adapted for the employment of water to keep the bed from blinding. Water is admitted through the pipe I 6 and the apertures I4 and preferably iills the entire space beneath the bed, as indicated in Figure 3. The level of the water may be set by the upper edge of the wall 1 which may be described as forming a discharge lip 1a. A circulation of water is maintained and of course there will be considerable splashing as the member 2I vrises and falls, squeezing water upwardly through the bed and sucking it downwardly back through the bed. 'I'his squeezing and suckingaction forces water positively through the interstices of the balls and keepsthemfrom blinding. Smallparticles are.

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sucked down through and large particles are prevented from wedging in between the balls or in the apertures of the foraminous plates B5, 66. Soft material, clay and the like, is also washed out in this fashion. A discharge of water over the lip la carries off the over size particles and the particles which pass through the bed pass oif with the water down through the passage 23.

In order to feed the form of the device shown in Figures l and following, where the discharge edge 'Ia passes circumferentially around the entire device, I employ a feed box 90. In order to support the feed box I illustrate vertical supports 9I extending upwardly from the outer wall 8. They may, for example, be welded thereto. One or more angle irons 92 extend across between the members 9I. Secured to them is a bearing block 93 in which is rotatably mounted a shaft 94 supported at the top as by a ball bearing structure 95. Secured to the lower end of the shaft 94 is a hub 96 connected by spider members 91 to the bottom of the feed hopper 9D. They may, for example, be welded. 98 is a central aperture in the bottom of the feed boxsurrounded, for example, by a down spout 99 which passes through the center of the flexible ring 85.

|58 indicates a feed pipe fixed, for example, in a bracket or lip I5! on one of the angles 92. It has a spout member E53 which is adapted to deliver water, with the mixed particles, into the feed box in such fashion that' the water or particles impinge against the bottom or inner face of the side of the feed box and causes the feed box to rotate. Thus the material, for example sand, is evenly distributed throughout the feed box and passes down the central aperture 98 and thus finds its way to the surface of the bed, for separation.

It will be understood that, whereas I have shown my device as used for the operation or classification or sizing of particles carried in water, that it may also be applied to air separation or to separation of particles carried by air. It will be understood, in the first place, that the material may be fed dry to the said hopper 90 or its equivalent, and may then be fed to the separating bed, water being employed otherwise as above stated. The water splashing up through the bed as the member 2l rises and falls will quickly wet the particles, and the said separation system can thus be worked with dry feed.

As a further variation in method, I may dis pense with the use of water altogether, and feed the material dry, and separate it dry. In that case, the air which blows up through the bed, or is sucked down through the bed, as. the member 2l rises or falls, performs the same function as the water. In such a case it may be desirable to employ gravity feed and to incline the bed and its support toward the edge. I illustrate a variant form of my device in Figure 9 and following in which a square bed is employed, in place of a circular bed. The supporting and actuating structure is substantially the same and will not be separately described, the same indicating symbols being employed. I illustrate, however, a rectangular top frame including angle members IBI! supported on the corner uprights 3. Clamped to the upper horizontal flanges III is a rectangular diaphragm 92, which may be of rubber or any suitable flexible substance. Flange ID3 may be secured thereto as by bolts IM. This flange may be a part of the upper box structure or housing IBS. One or more inlets 06 may admit water from any suitable source. Figure 9 illustrates one of the inlets IUS closed by a pipe plug Hita. lill is a bottom hopper clamped to the inner edge of the diaphragm |92 as by any suitable clamping means IGS. IGS is any suitable run olf outlet. It is understood that the construction generally follows that of Figure l and following. However, the reducing member 261 may directly discharge the material into any suitable chute I It diagrammatically indicated in Figure 10. l

Closing the top of a space so defined is the separation bed proper which includes transverse grill members III, conforming in detail to the spider members 69, t4 of the earlier described form. Thebed structure is substantially the same except that the individual ball cells are defined by a rectangular grill generally indicated as IIE.

In Figure l0, I illustrate a section in which the bed is substantially horizontal. rIhe material, water flowed, may pass over the single lateral discharge lip I I6 into any suitable discharge chute itl. In Figure ll, to indicate air separation, I illustrate the deck or bed as substantially tilted toward the discharge edge.

Any suitable feeding means may be employed,

.for example a delivery chute H8, but I do not illustrate them in detail.

As will be seen in Figures 9 to l1, three of the Walls I i9 of the housing m5 extend above the bed structure to conne and .guide the material upon said bed structure.

Whereas it may be under most circumstances desirable to hold the balis between two foraminous disks, 55a and 66a respectively, under some circumstances it is practical to omit the upper disk. I have done this in Figures. 9 and 10, where larger balls are shown. It will be understood that I may at will use or remove the top foraminous plate 6Go', shown, for example, in position in Figure ll. It is omitted from Figures 9 and 10.

The bed structure may be held in position upon the housing I5 by bolts I.

Referring to- Figure l2, I have illustrated improved water inlet means particularly adaptable for the device illustrated in Figures l to 8 in order to deflect the clean incoming water upwardly and towards the wall 'I of the ring structure 5. This results in obtaining in effect a wall of clean water and confining the muddy water to be discharged together with the screened material through the outlet 22. The outlets Illof the channel i2 may be provided with L-shaped tubes iii to defies the fluid in the direction of the arrows. However, suitable balile plates may be positioned, adjacent the'outlets Ill to deflect the water in a similar manner.

It will be realized that, whereas I have described and shown a practical and operative device, nevertheless, many changes may be made in size, shape, number and disposition of parts. I, therefore, wish my description and drawings to be taken as in a broad sense illustrative or diagrammatic, rather than as limiting me to the specific details of the present disclosure. It will be understood that I may employ either air or water, either a gas ora liquid, to assist in the sizing. It will be also understood that a wide variety of feeding means may be employed.

Preferably the balls are round, but I can obtain my effect with balls or particles which are notl strlctly round. The ballsI or separate particles may be widely varied in size and considerably varied in shape. When I employ the term ball in a claim, it will be understood as being intended to be interpreted with sufficient breadth to cover particles. which are not.- actually spherical.

Whereas I have shownv foramlnoustplatesaitwill; be understood that. I may, if I wishiemploy screening, and, .whenin the claim Iemploy the. term screen it will'beunderstood as intending Y tov include a feramincus plate or its-equivalent;

In the operation of my devicethe suction of air, gas or: water on the down-stroke of themember 2l is of greatrimportance as it positively sucks or draws the particles downinto the interstices of the bed and pulls the undersize particles all the way through. It is owing to this suction action, this positive drawing of the material.. through the bed, that I am able to get a very great emciency with a bed in whichthe .proportion of open area is as small as it is. For example, in atypical case, the open area of my bed may be no more than 8 per cent of the superficial area of the bed, whereas a commercial screen may have as high as 90 per cent. None the less,

whereas in the screen the material may havefto dance around on the surface until it finds a hole, in my bed. the particles are drawn into and through the spaces by positive suction.

On the upstroke of the member 2|, the fluid is forced through the bed, expelling any oversize particles or groupings of undersized particleswhich may tend to blind the bed. Inasmuch as a certain relative movement of ball in relation to ball is permitted, the cleaning of the voids is much easier than it would be if all the apertures were` of fixed size. Any aperture inthe bed, since it is defined by relatively movable particles, variesslightly in diameter, under pressure, and permitsthe alternate suction and expulsion to clean the pores or apertures of the bed, as it shifts their diameters.

Preferably I confine the balls or particlesforming my sizing bedsuii'iciently to prevent'. their having any substantial grinding action.

40 Referring, `for example to Figures 7 and 8, they may be confined between the lower screen `65 and the upper screen 66 and they are also confined laterally by the` intermediate partitionsl 61.' It will be understood, however, that-Imay under some circumstances, especially Where large balls are employed, omit the upper screen. In that case gravity, in connection with the lower screen and thelateral partitions, provides whatever confining effect is necessary. In any case, the balls 50,; must be free to have at least a limited movement `in response to the movement of air or liquid through the bed because, by such a movement, the freeing of the bed from blinding is obtained. But a relatively slight movement is suflicient and 55. the possbility of a large movement would have the two-fold disadvantage of causing undesired grinding and degradation and also of causing variation in the size of the particles passingA through the bed. When, in .any claim I describe l, the balls or particles as confined it will be understood that I mean not a complete confinement of the particles against movement but confinement sufficient no matter how obtained, to hold the balls against excess and undesiredv movement,

while permitting to the individual balls sufficient IU'I of Figure 11,- to gveone example,.is sufficient.

toi-obtain my.-result, and'Iv do ynot have to providefadditionaliain under pressure. When I employ water asazmedium, the supply has to be maintained; preferably constantly, by the additionLoffurtherfwatehas through the pipe I6 of Figure- 3; since water: is continually passing over the discharge lip and flowing into the trough 5. I may employ any suitable check valve IDSazin theline,v |09 Vin order tolimit the flow of liquid through the said line'.

fr-.furtherV use of my sizing device consists in the employment' oftheA screens'themselves, the mesh 6512 andv 66,.or5a singlescreen, where only oneis used, as in'LFigureiQ, to size or separate the particles, While" employing 1 the balls, or their equivalent,.as.means:for maintaining the mesh clear andfunblinded:v Inzsuch case, where the meslfi'oflthexscreen determines the size of .the particles -'and' not the interstices between the balls, therballs.neednot-'abua ora greater freedom of movement may betallowed the balls, and a great range inither size of the aballs.. In such case, the primaryrfunctionof the balls is not to determine thesize of fthefparticles-which pass through the sizing bed; butito' insure that the apertures of the screen are kept unblinded.

I claimt.

l. In asizing device, a sizing bed which includesa plurality of abutting balls of uniform sizeand'lshape, arranged fin a'relatively thin layer, means forl holding. said ballsv against substantial relative movement while permitting a slight movementV of individual balls, the interstices between balls constituting vsizing apertures,

m'eans-.fory deliveringfto the topof the bed the material to .be sized, andmeans for clearing the intersticesnofithe bed, and for drawing the ne particles downwardly through the bed, including a-moveable member, a uid in the space between the bed andthe movable member, and means for imparting movement to the movable member and for therebyl causing. the fluid to move alternately in'. opposite directions through the bed, the top ofi th'es bed' being free from projections which would prevent therfreedischarge of oversize particles.

2.' In asizing device, a sizing member, means forfdeliveringto the sizing member the'material toY be` sized,: a 4pulsating member positioned beneath .the sizing member, means for maintaining the space between the pulsating member and the sizingmember lledwith aliquid, means for reciprocating:saidipulsating member and thereby causing. the. liquid to moveA alternately in opposite directions through the sizing member, said pulsating member'includinga hopper and a exible diaphragm connection betweenA the upper edge of': saidhopper and-the rest of the sizing device, adapted'to vcooperate as a portion of said hopper, thei-sizingmember' including a plurality ofab'uttingaballs of.' generally uniform size and shape arrangedin a relatively thin layer, and means zfor holding said balls against substantial relative movement while permitting a slight movement of :'thefindividual balls, the interstices between balls constituting the sizing apertures.

3'. Thefmethodof sizing particles which includesrrmaintaining, in a sizingzone, a plurality of r substantially contacting, relatively movable members. of 'substantially uniform size and shape, whereby the apertures between adjacent membersfare'; of substantiallyuniform cross section, restrictinglthe'movement of said members to permitfa'islight .relative movement, while preventing anyf.-v substantial variation in the cross-sectional area of the apertures therebetween, causing Va fluid to iiow through the zone of separation alternately in opposite directions, drawing the undersized particles by suction of the fluid downwardly through the sizing zone, carrying off the oversized particles across the upper face of said zone, and carrying oli the undersized particles from beneath said zone.

4. In a sizing device, a sizing member which includes an upper pervious partition and a lower pervious partition, and a body of balls of substantially uniform size positioned between said two partitions whereby the apertures between adjacent balls are substantially uniform in cross sectional area and constitute sizing apertures, the balls substantially filling the area between said partitions, suflicient room being left to permit a slight relative movement oi the balls, and means for maintaining a body of liquid at a level corresponding generally to the level of the upper pervious partition and means for pulsating said liquid.

5. In a sizing device, a sizing member which includes an upper pervious partition and a lower pervious partition, a body of balls of substantially uniform size positioned between said two partitions whereby the apertures between adjacent balls are substantially uniform in cross sectional area and constitute sizing apertures, the balls substantially illing the area between said partitions, suiiicient room being left to permit a slight relative movement of the balls, and means for maintaining a body of liquid at a level corresponding generally to the level of the upper pervious partition, including a lip terminating generally at the level of said upper pervious partition and means for pulsating said liquid.

6. In a sizing bed, upper and lower spaced foraminous members, a plurality of balls of substantially uniform size arranged in superposed layers in the space between said foraminous members and substantially filling the space therebetween, the interstices between balls constituting sizing apertures smaller than the apertures in said foraminous members, said foraminous members being adapted by their close approach to permit slight relative movement of the balls while preventing movement sufficient to vary the cross sectional area of the apertures between adjacent balls, the bed so formed being adapted for the pulsation of a fluid therethrough.

7. In a sizing device, a bed, including a plurality oi abutting balls of substantially uniform size arranged in a relatively thin layer, the interstices between balls being substantially uniform in size and constituting sizing apertures, means for delivering to the bed the material to be sized, and means for clearing the interstices of the bed, including a movable member, a iiuid in the space between the bed and the movable member, means for imparting movement to the movable member and for thereby causing said iiuid to move alternately in opposite directions through the bed, and means for limiting the balls to a movement insuiiicient substantially to change the gauge of the apertures between the balls.

8. In a sizing device, a sizing bed which includes a plurality of abutting balls of uniform size and shape, arranged in a relatively thin layer, means for holding said balls against substantial relative movement While permitting a slight movement of individual balls, the interstices between balls constituting sizing apertures, means for delivering to the top of the bed the material to be sized, and means for clearing the interstices of the bed, and fordrawing the line particles downwardly through the bed, including a movable member, a fluidin the space between the bed and the-movable member, and means for imparting movement to the movable member and for therebycausing the fluid to move alternately in opposite directions through the bed, the top of the bed being free from projections which would prevent the free discharge of oversize particles, and a ldischarge edge member for the bed, remotel from the area of the feed and lying at the general level of the bed;

9.. In a sizing device, a sizing bed which includes a plurality of abutting balls of uniform size and shape, arranged in a relatively thin layer, means for holding said balls against substantial relative movement while permitting a slight movement of individual balls,Vv the interstices between balls Yconstituting sizing apertures, means for delivering to the top of the bed the material to be sized, and means for clearing the interstices of the bed, and for drawing the ne particles downwardly through the bed, including a movable member, a. iiuid in the space between the bed and the movable member, and means for imparting movement to the movable member and for thereby causing the fluid to move alternately in opposite directions through the bed, the top of the bed being free from projections which would prevent the free discharge of oversize particles, and a discharge edge member for the bed, remote from the area or the feed and lying at the general level of the bed, the bed being inclined downwardly from the area of feed toward the discharge edge.

10. In a sizing device, a sizing bed which includes spaced upper and lower pervious members, and a plurality of substantially uniformly sized balls located in and substantially lling said space, whereby the apertures between adjacent balls are substantially uniform in cross sectional area, and constitute sizing apertures of a smaller gage than the apertures of said pervious members, there being suilicient space in said bed to permit a slight relative movement of said balls, the top of the bed being free from projections which would prevent the free discharge of oversize particles across and from the top of said bed, said bed being adapted for the passage of a fluid therethrough.

11. In a sizing device, a sizing bed which includes spaced upper and lower pervious members, and a plurality of substantially uniformly sized balls located in and substantially iilling said space, whereby the apertures between adjacent balls are substantially uniform in cross sectional area, and constitute sizing apertures of a smaller gage than the apertures of said pervious members, there being sufcient space in said bed to permit a slight relative movement of said balls, the top of the bed being free from projections which would prevent the free discharge of oversize particles across and from the top of said bed, said bed being adapted for the passage of a uid therethrough, and means for pulsating a fluid through said bed and for thereby causing a slight movement of said balls and causing a suctional withdrawal of fine particles downwardly through said bed.

12. In a sizing device, a sizing bed which includes spaced upper and lower pervious members, and a plurality of substantially uniformly sized balls located in and substantially iilling said space, whereby the apertures between adjacent balls are substantially uniform in cross sectional area, and constitute sizing apertureslof a smaller gage than the apertures of said pervious members, there being suificient space Ainsaid bed to permit a slight relative movement of said balls, the top of the bed being free from projections which would prevent the free discharge of oversize particles across and from the top of said bed, said bed being adapted for'the passage of a uid therethrough, and an impervious cover eX- tending across the top of said bed and terminating adjacent the discharge edge thereof and means for feeding material to be separated to the top of the upper pervious member, and beneath said imperviousV cover.

13. In a sizing device, a sizing bed which includes spaced upper and lower pervious members, and a plurality of substantially uniformly sized balls located in and substantially lling said space, whereby the apertures between adjacent balls are substantially uniform in cross sectional area, and constitute sizing apertures of a smaller gage than the apertures of said pervious members, there being suicient space in said bed to permit a slight relative movement of said balls, the top of the bed being free from projections which would prevent the free discharge of oversize particles across and from the top of said bed, said bed being adapted for the passage of a fluid therethrough, said upper and lower pervious members constituting foraminous plates.

14. In a sizing device, a sizing bed which includes spaced upper and lower pervious members, and a plurality of substantially uniformly sized balls located in and substantially lling said space, whereby the apertures between adjacent balls are substantially uniform in cross sectional area, and constitute sizing apertures of a smaller gage than the apertures of said pervious members, there being sufficient space in said bed to permit a slight relative movement of said balls, i

CHARLES E. WOOD.

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