US2353903A

US2353903A - Granular material grader and purifier

Info

Publication number: US2353903A
Application number: US470178A
Authority: US
Inventors: Johnson Leonard; Martin A Rieman
Original assignee: Hart Carter Co
Current assignee: Hart Carter Co
Priority date: 1942-12-26
Filing date: 1942-12-26
Publication date: 1944-07-18
Anticipated expiration: 1961-07-18

Description

July 18, 1944. JOHNSON HAL 3 2,353,903

GRANULAR MATERIAL GRADER AND PURIFIER I Filed Dec. '26, 1942 s Sheets-Sheet 1 I fnvenions v m5==ra==r [fa/YARD JOHNJO/V MAer/n ,4. IP/EMAN Aiiiornegz 1 y 1944- JOHNSON ET A1. 2,353,903

GRANULAR MATERIAL GRADER AND PURIFIER Filed Dec. 26, 1942 5 Sheets-Sheet 2 ZEOIVAPD Jaw/v50 MART/IV ,4. F/EMAN 4y MMJJVZM AZ Earn/e575 L. JOHNSON ET AL 1 July 18, 1944.

GRANULAR MATERIAL GRADER AND IURIFIER 5 Sheets-Sheet '3 Filed Dec. 26, 1942 y 944. JOHNSON ET AL 2,353,903

GRANULAR MATERIAL GRADER AND PURIFTIER Ara/mm JOHMSQ/V MART/N A. KEN/2Z iz verv Z071;

July 18, 1944. L. JOHNSON ET L 2,353,903

GRANULAR MATERIAL GRADER AND PURIFIER Filed Dec. 26, 1942 5 Sheets-Sheet 5 AZZ07-7095 Patented July 18, 1944 GRANULAR MATERIAL GRADER AND URIFIER Leonard Johnson and Martin A. Rieman, Minneapolis, 'Minn., assignors to-Hart-Carter Company, Peoria, Ill., a corporation of Delaware Application December 26, 1942, Serial No. 470,178

30 Claims.

This invention is directed to the provision of an improved machine for grading and purifying granular materials; and is in the nature of an improvement on or modification of the machine disclosed and broadly claimed in the pending application of William N. Smith, filed of date November 2'7, 1940, under Serial No. 367,477, now Patent Number 2,331,850, granted Oct. 12, 1943, and entitled Granular material classifier or purifier. The machine of the said Smith application and. the machine of the present application accomplish the selection and grading of the granular materials, by the co-action of'centrifugal force, gravity, and controlled air currents, and effect the separations and grading of the different materials into groups according to the specific gravity of the various materials or particles of the aggregate.

Broadly stated, these machines will operate to accomplish the above separations of many different kinds of materials or granular mixtures, but have been designed especially for the separation, into groups, of the various particles of middlings produced in the well-known fiour milling operations. spect to the prior Smith machine and to the improved machine of this present application. I For convenience, the present machine and its operations will be particularly described as a middlings grader or classifier and purifier. Briefly outlined, the present improved machine involves a casing provided in its upper portion with means for producing an approximately semi-spherical or umbrella-like shower of the commingled middlings; and this means includes a sprayer head, preferably a cup or dished, mounted to rotate at high velocity. Below this cup, in position to receive the shower, is the grading or classifying meanswhich involves a rotary upper table and an underlying non-rotary lower table or structure. The rotary upper table has concentric grading channels and intervening imperforate table surfaces; and the lower table has concentric trough-like receiving channels that underly and receive directly from the overlying gradin channels of the upper table.- The rotary upper table has depending sweepers that are arranged to travel in the trough-like receiving channels of the lower table, and under rotation. of the upper table, to carry the materials in said trough-like channels toward and to discharge ports provided in the latter.

Deflectors, preferably of the wedge or V-type, are mounted immediately over the imperforate tabl surfaces of the upper table and operate to The above statements are true both in redeflect the materials into the grading channels of said upper table. These deflectors are fixed in respect to the rotary upper table but are preferably mad-e adjustable laterally or radially of the table to vary their deflecting actions.

The so-called sweepers that are carried by the rotary upper table and move in the trough-like channels of the lower table may take different forms; and, preferably, in the improved machine, there is employed sweepers of two types, to wit: primary sweepers in the form of blades that function to move the materials in the troughs and carry the same to the discharge ports; and secondary sweepers in the form of brushes or the like that may be brought into action occasionally to sweep out and clean the troughs for the purpose of sanitation.

The dished or cup sprayer head referred-to above is preferably arranged to work at the upper portion of a tubular air bafiie and to discharge the umbrella-like spray of materials radially outward and 'over the top thereof. To prevent rotary circulation of air in the casing, this tubular air bafile is preferably provided with outward or radially projected baffle blades or fins.

A tubular air suction stack leads from the interior of the tubular bafiie to a suction fan or the like; and the connections to the fan or source of ,partial vacuum preferably include means for varying the extent of the vacuum or suction. Of course, the purpose of this fan or other source of suction is to produce a desired but controlled flow of air more or less radially inwardly through the annular shower of material sprayed or pro jected from the rotary sprayer head with a view of widening the degree of separation. In this arrangement, while the connections leading to the fan or blower preferably include an air fiow control, the main control is preferably established at the inlet to the casing and, for this purpose, a plurality of controlled air inlet passages or ports is provided in circumferentially spaced relation about the axis of the upper portion of the dome. As a feature of this invention, we provide a Very simple but highly effective medium through which the air flow capacity of each of the several said air inlet passages may be adjustably varied. While controlled air flow, as above pointed out,

through the dome and downwardly and inwardly through the shower of material, is important, it

has also been found that the separation can be widened and further improved by also taking in some air upwardly through the so-called table structure, and moving this air upwardly and inwardly through the shower of material, and the table structure of this machine is designed to provide for such movement of air when the easing is subjected to partial vacuum.

All of the above and various other important and novel features will more fully appear in the description of the accompanying drawings which illustrate a commercial form of the improved machine.

Referring to the drawings, wherein like characters indicate like parts throughout the several views:

Fig. l is a front perspective of the improved machine;

Fig. 2 is a horizontal section taken approximately on the horizontal line 2-2 of Fig. 1 showing the rotary upper and non-rotary tables, ap-

proximately one-half of the uprpertable being Fig. 8 is a'detail in plan showing one of the V-typedeflectors and its adjustable supporting means;

Fig. 9 is a section taken on the line 9-9 of Fig. 8' and showing also in section a portion of the'underlying rotary upper table;

Fig. 10 is a section taken on the line lflili of Fig. 4 showing a damper and control for varying the suction in air flowing action through the machine; and I Fig. 11 is a fragmentary vertical section taken approximately on the line H-H of Fig. 2.

Fig. 12 is an enlarged fragmentary View of the upper portion of the casing.

The various operative parts of the machine are contained within a cylindrical casing 28 preferably of sheet metal shown in Figs. 1, 3 and 4 and provided with a semi-spherical dome or cover 2| At the axis of the dome it is provided with an inlet for the entry of the commingled material into the machine. This stock inlet may be of any approved form and, for the purposes of this case, it is only desirable to note a stock inlet comprising tubular sections 22 and 22a that are in alignment with the axis of the casing.

plate, suitable stud bolts 23?) are anchored to the control plate and project through segmental slots 230 (see Fig. 1) in the dome 2i, and these studs 231) are provided with finger nuts 23d that overlap the segmental slots 230. Of course, with this arrangement the

air inlet ports

23 and 23" may be brought into full alignment for maximum air flow and may be brought into partial or complete misalignment for reduced air flow.

The casing is shown as being supported by short legs 24 and certain important elements of the machine, hereinafter to be described, are supported by a casing spanning sub-structure 25, as

' The air inlet ports or passages in the dome 2i,

and of which there are several circumferentially spaced series concentrically disposed about the axis of the dome, are indicated by 23. The means for controlling the rate of air flow inwardly through these several passages 23 include a rotatively mounted control plate 23, having air passages or ports Z3 that correspond in size, number, and spaced relation to the ports or passages 23. The said control plate 23 is annular and shaped to conform to the shape of the overlying portion of the dome 2i and is rotatively supported at its inner edge by a mounting ring 23 that overlaps the inner edge of the control plate 23, and is anchored to the dome by nut-equipped bolts or the like 23d. For the purpose of maintaining the control plate 23 centered and for preventing binding thereof, a suitable spacer ring 23a is interposed between the mounting ring and the dome For the purpose of adjustably moving and anchoring the control best shown in Figs. 3 and 4. Located within the intermediate portion of the casing and below the dome or cover 2| is a mechanism supporting structure in the nature of a series of circumferentiallyspaced radially extended beams 26, shown best in Figs. 2 and 4.

Rigidly secured'to the inner ends of the beams 25, at the axis of the casing, is a tubular memher 2? that serves as an axial bearing and as an air outlet or suction tube, as will hereinafter more fully appear. The outer ends of the beams 26 are anchored to the side of the casing, as best shown at 26' in Fig. 4.

The rotary upper table, referred to in the above introductory statements, is indicated as an entirety by the character A and the lower nonrotary table is indicated as an entirety by the character B. The body portion of the upper table A is preferably made of sheet metal and is formed with concentric grading channels 28 and intervening imperforate table surfaces 29; and the above noted elements of this upper table are rigidly secured to an axial hub 30 mounted to rotate on the tubular member 2?, preferably by ball bearings 35 of well-known type, and which latter support the upper table for very free rotation, but hold the same against axial movements on the said tubular member 21.

The hub 39 of the rotary upper table is formed with or rigidly secured to a quite large spur gear 32 that meshes with a driving pinion 33 on the upper end of a vertical shaft 34, which latter is supported and driven in a manner hereinafter described.

The non-rotary lower table B is made up of a plurality of concentric elements, also preferably of sheet metal, and comprising a plurality of concentric radially spaced trough-like receiving Channels 35, all rigidly secured directly or indirectly to the underlying radial beams 26 by nutequipped bolts 33 and short clamping bars 43', as best shown in Fig. 4. The grading channels 28 of the rotary upper table A are provided with depending cylindrical flanges 36 that depend into the underlying-trough-like channels 35 of the lower table.

In the particular structure illustrated, the rotary table A is of somewhat less diameter than the casing 20, and hence, at its outer edge is formed with but one depending flange 35' that projects into an outer annular receiving channel 35" formed at the extreme outer portion of the fixed lower table B, as best shown in Figs. 3, 7 and 11. 7 Of course, the number of grading channels r ided in the upper table and the number of receiving channels in the fixed lower .table may be varied, but, as shown in the drawings, there are five channels, to wit: four of the said channels '35 and the additional outer channel 35'.

At the proper place for discharge, the

troughlike receiving channels

35 and 35 are provided each with its own independent discharge port 31 from each of which discharge ports a discharge spout '38 is extended downward to independent places for discharge, as best shown in Fig.3.

The rotary upper table is provided with a multiplicity of primary sweeper blades 39 that work in the respective underlying channels or troughs of the fixed lower (table and progressively move the collected materials to the respective discharge ports 31, under rotation of the upper table. These so-called primary sweepers are preferably arranged so that a plurality thereof, properly circumferentially spaced, will work in each of the said trough-like receiving channels of the lower table.

From the foregoing it will be noted that the rotary upper table A is, in this preferred machine, made up of

sheet metal elements

29 and 35 that are assembled to form concentric inverted trough-like sections. To properly space and connect the said elements for rotation with the hub 30, as an interconnected unit, the said sections are bound together by a plurality of circumferentially spaced arms connected to and radiating from the hub 3|]. These arms, as shown, are formed by rods 40, (see Figs. 2 and 7), and surrounding sleeves 4|. Rods 48 are shown as provided with threaded inner ends screwed into the flange of hub 30 and provided at their outer ends with nuts 42 that rigidly clamp the sleeves 4| against rotation on said rods. The sweepers 39 are shown as secured to the sleeves 4| and depend vertically therefrom.

The elements of the non-rotary lower table 13 are further and, in fact, primarilytied together by radial bars or members 44 that are located circumferentially intermediate and in staggered relation with respect to the radial beams 26 to which radial bars the trough-forming sections are rigidly secured by suitable means such as rivets 44'. The outer ends of the bars 44 are rigidly secured to the casing side, as indicated at 44" inFig.7.

The V-type deflectors, that work directly over the imperforate table surfaces 29 of the rotary upper table, are indicated as entireties by the'numeral 45, (see particularly Fig. 2). These deflectors are adjustably supported from a fixed bracket or support 46 which, as shown, is V-shaped and is rigidly secured to the interior of the casing 2|! and extends directly over the table surfaces of the said upper rotary table, (see also Figs. 3, 8 and 9). The backs of these deflectors 45, by suitable means such as a set-screw 41, (see Figs, 8 and 9), are secured to a U-shaped arm 48, one prong of which is pivoted to a hinge lug 49 rigidly secured to the front arm of the supporting bracket 46. The outwardly extended ends of the depending arms 48 are independently connected to plunger-acting links 50 that are extended outward through the casing 20, as best shown in 2, and into a small indicator box 5| rigidly se cured on the exterior of the casing, as best shown in detail in Fig. 6. Pivotally mounted within the box 5| are rocker arms 52, one for each deflector provided at their upper ends with coupling pins 53 that engage notches 54 in the outer ends of said bars 50. At their lower ends, the rocker arms 52 are provided with pivotally connected nuts 55 engaged by the threaded ends of stems 56 provided at their outer ends with operating knobs 51. Also, as preferably arranged, the rocker arms 53 are provided with indicator fingers 53 that project through slots formed in the box 5! and arranged to engage with graduated indicator scales 59 to indicate the lateral adjustments of the several deflectors.

The axially located tubular combined bearing and air suction tube 21 which, it will be remembered, is rigidly supported from the beams 26, is provided with a tubular upper end extension 60, the upper end of which is closed and provided with a bearing hub 6|. Said extension 60 is provided with large circumferentially spaced air intake ports 62.

Extended axially upward through the

tubular members

21 and 60 and journaled in the hub 6| (by means of ball bearings 63) is a. high speed shaft or spindle 64. At its lower end said shaft or spindle 64 is journaled in a bearing 65 shown as applied to the horizontally extended air tube 66. This tube 66 forms an extension of the air conduit formed by the sleeve 21 and its extension 60, and in practice, will lead to a suction fan, not shown, but which will preferably be located outside of the casing. The tube 66 and bearing 65 are thus rigidly supported indirectly from the beam structure 26.

A conical shield 61, preferably of sheet metal,

is secured to the rim of the hub 30 just radially inward of the innermost grading channel 28. The upper end of this conical element 61 closely engages around the tube extension 50 and is overlapped by a flaring annular ring 68 secured on the said tube extension, as best shown in Fig. 4.

The tubular bafiie tube 69, briefly referred to in the introductory statement, is preferably a sheet metal shell that is of much greater diameter than the non-rotary extension 60. This shell 69 is spaced concentrically around the non-rotary tube extension 60 and is rigidly secured thereto by means of metallic brackets 10. Said tube or shell 69 is shown as provided with circumferentially spaced air ports I I.

The centrifugally actin sprayer head, which delivers the middlings or granular material into the casing in the form of a shower may, so far as this invention is concerned, vary considerably in form, but in the form and arrangement shown, involves what is believed to be novel and patentable features which may be made the subject matter of a companion application. As shown, said sprayer head is in the form of dished body shell '12 having an outstanding flange 13 that is slightly spaced from and does not engage with the upper end of the stabilizer shell or tube 69. This dished body portion 12 is secured to a hub 14 which, in turn, is rigidly secured on the upper end portion of the high speed spindle 64. The extreme upper end of spindle 64 is shown as provided with a conical head 15 which works in the contracted lower end of the intake tube 22 and in co-operation with the contracted end of said inlet tube regardless of the flow of the stock to the dished or cup-shaped sprayer head. Applied concentrically over the sprayer head is an inverted conical spreader 12'.

Circumferentially spaced bafile blades or vanes 16 are secured to the tubular air control baffle or shell 69 and radiate therefrom. These blades l6 extend substantially in planes that radiate from the axis of the rotary table and other rotary parts of the machine and they perform important functions which will more fully appear in the description of the operation.

In this improved machine means will be pro vided for rotating the spindle or shaft 64 at high speed and the shaft 34 at relatively low speed; and such means may vary. In the arrangement shown, the spindle 64, at its extreme lower end,

is provided with a grooved pulley 11, (see Figs. 3 and 4), over which is arranged to run a powerdriven belt 18. This belt 18 may be driven in various different ways but, as shown, is arranged to run over a pulley 19 carried by a primary power shaft 511. Also, as illustrated, the belt "I8 runs over an idle or slack take up pulley 8I which, as shown in Fig. 3, is mounted on a stub shaft 82 of a bracket 83 supported by parallel link 84 subject to a suitably anchored tension spring 85. The specific structure of the take up device above noted is not herein claimed, and hence, for the purpose of this case, it is thought to be sufficient to state that by the means illustrated high speed rotary motion will be imparted to the spindle 64 and to the cupped sprayer head 12.

- In the particular arrangement illustrated shaft 88 is shown as journaled in suitable bearings on a trussed bracket 86 and in a projecting housing 3? rigidly secured, the former to the interio and the latter to the exterior of the casing, (see particularly Figs. 2 and 3). In Fig. 2 shaft 89 is shown as provided, at its outer end, with a pulley 88 over which a power-driven belt, not shown, may be run to convey power and motion to the machine.

Shaft 34 is journaled in an upper bearing 89 on beam 26 and in a lower bearing 90 on the lower beam 25, and at its lower end is provided with a spur gear 9I. Gear BI meshes with a spur pinion 92 carried by a short shaft 93 journaled in a bearing 94 on beam 25. At its upper end shaft 63 carried a pulley 95 that aligns with a relatively small pulley 96 formed on the hub of pulley ll. y the means just described high speed rotary motion will be imparted to the spindle 64 and its cupped spraying head, and relatively low rotary motion will be imparted to the upper table A and the cone 61.

In Figs. 2 and 11 there is illustrated-a cleanout sweeper, sometimes referred to as a secondary sweeper, adapted to occasionally and temporarily used to effect final sweeping out or cleaning of the channels of the lower non-rotary table;

This clean-out sweeper involves a rock-shaft 98 that is mounted in the rotary upper table just below the top thereofland extends radially of said table and, of course, travels with the upper table when the latter is rotated. This rock-shaft 98 is provided with quite stiff brushes 99 which normally are raised out of the channels of the lower table, and hence, are inoperative or idle but which, by oscillatory movements of rockshaft 98, are adapted to be turned down into the channels or troughs of the lower table, as shown in Fig. 11. At its inner end, rock-shaft 98 is provided with an arm I09 that is adapted to be engaged by the projecting pin IIII of an arm I02 of a short shaft I63. Shaft I03 is mounted in a bearing EM shown as supported on the cone 61. At its outer end shaft I03 is shown as provided with a lever I95. Pin IIlI works in a slot in the end of arm I89 so that by oscillatory movements of lever IE5, shaft 93 can be oscillated to carry its brushes 99 either into operative or inoperative positions, at will.

In Fig. 4 there is shown a tension spring I which yieldingly holds arm I02 in whichever position it may b set on one side or the other of a dead center in respect to the tension of said spring.

, Attention is now directed particularly to Figs. 4 and which show means for regulating the partial vacuum or suction produced in the air A belt Bl runs over the pulleys 95 and ill conduit made up of the

tubular elements

21 and 60. Suction tube 66, at its elbow, is shown as provided with an auxiliary air intake port I 06 that is adapted to be closed or opened to a greater or less extent by a segmental rotary damper I01 carried by a shaft I08 journaled in a bracket I09 secured to and dependin from beam 26. Shaft I08, by intermeshing miter gears III], is connected to a long operating shaft III which, as shown in Fig. 2, extends to the exterior of the casing and, as shown, is provided with a handle or head H2. On the inner end of shaft III is a friction wheel H3 that is engaged by a friction band I I4 that is anchored to the bracket I 09 and exerts enough friction to cause damper I01 to remain indifferent set positions against accidental movement.

In the dome 2| of th casing there is one or more transparent windows or peek holes H5 and a transparent door II6, which latter iscapable of being readily opened so that the arm of the operator 'may be inserted and engage the lever I95, the operation of which throw the clean-out brushes 99 into or out of action. I

Operation When the machine is in operation, the rotary upper table A willbe slowly rotated in a clockwise direction in respect to Fig. 2 and the spindle '54 and its sprayer head or cup will be rotated in the same direction but at a very much higher velocity. In this preferred form of th machine illustrated, the spreader or deflecting cone 61, the tubular bafile 69, and the bafile blades I6 will not rotate with said upper table, but will remain stationary as above indicated. The sprayer head or cup I2 will be kept properly supplied with the commingled stock, assumed to be middlings, and. underhigh velocity of the cup, the stock will be centrifugally discharged from said cup over the upper edge of the tubular baffle 69 and will fall in an approximately semispherical or umbrellalike shower onto the rotary upper table. The heavier particles of the middlings or commingled stock will be projected radially outward far.- ther than the lighter particles, so that under the combined action of centrifugal force and gravity the stock will fall onto the upper table at distances from the axis of the table proportionate to the specific gravity of the particles. Some of the particles will fall directly into the grading channels 28 of said upper table, but a large part of the stock will fall onto the ims perforate intervening table surfaces 29.

Under rotation of the upper table the material, caught on top of the table surfaces, will be carried against the overlying V-shaped deflectors, and, by the latter, will be deflected or forced with a plow-like action into adjacent grading channels. When the deflectors are set as shown in Fig. 2, the materials on the table surfaces will be scraped or deflected, in about equal amounts, into the two immediately adjacent channels. By lateral adjustments of the deflectors they may be set to scrape or deflect all of the materials, from any particular table surface, into one adjacent grading channel, or, they may be set so as to vary the proportionate amounts delivered into adjacent channels to any desired extent. Independent adjustment of the deflectors 45 may be accomplished from the exterior of the casing by manipulation of the exposed operating knobs 5'1. Said deflectors, as above noted, are independently adjustable. By the use of the deflectors and proper adjustments thereof, variation in the grading, initially accomplished by centrifugal force and gravity, may be varied to substantially infinitesimally small degrees.

All of the material delivered into or through the grading channels 28 of the upper table will, by the flanges 36, be directed into the immediately underlying trough-like channels of the nonrotary lower table.

Under rotation of the said upper table, its

sweeper blades 39 will move the materials in the trough-like channels of the lower table, progressively, until it is delivered to and discharged through the delivery ports 31 of the respective receiving or catch troughs 35 and 35'. Materials dropped through the ports or delivery passages will, by the respective spouts 38, be delivered to the appropriate points for discharge. In the present instance the spouts 38 are assumed to deliver to different parts or receptacles, but recommingling of the various materials, when Under rotation of the said upper table, its

sweeper blades 39 will move the materials in the trough-like channels of the lower table, progressively, until it is delivered to and discharged through the delivery ports 31 of the respective receiving or catch troughs 35 and 35'. Materials dropped through the ports or delivery passages will, by the respective spouts 38, be delivered to the appropriate points for discharge. In the present instance the spouts 38 are assumed to deliver to different parts or receptacles, but recommingling of the various materials, when found desirable, may be accomplished by wellknown means not necessary for the purpose of this case to consider.

In the foregoing, the operation of the machine has been described without regard to the controlled air currents moving downwardly and inwardly and upwardly and inwardly through the shower of material, but it should be understood that, for most classes of stock, the degree of separation can be materially improved by the proper use of such air currents, When the machine is once set in operation in connection with any particular class of stock, the operator will adjust the damper N11. to provide the desired degree of suction and, while viewing the separating action through one of the peek holes orinspection windows H5, will rotatively adjust the air control plate 23 to thereby vary the air flow through the air intake ports 23 to the point where the separating action appears most effective and efficient. With this accomplished, air in desired volume and velocity will move inwardly through the dome air intake ports 23, and will pass downwardly and inwardly through the shower of material into the extension tube 66 through the ports H in the tubular baflie 69 and through the opening bottom of the tubular bailie 63, and other, and, in fact, annular, currents of air will move upwardly through the table structure and grading channels 28 and will pass upwardly and inwardly through the annular shower of material to the extension tube 60 through the intake ports 62 therein. These downwardly and inwardly and upwardly and inwardly moving air ourrents are of low velocity, and will tend to carry the sprayed stock radially inwardly toward the axis of the machine, but will be far more effective on the particles of least specific gravity and,

hence, will essentially widen the degree of separation of lighter from heavier particles by carrying the lighter particles further toward the axis of the machine than will be the case in connection with the heavier particles. Of course, under the action of centrifugal force and gravity the particles of greatest specific gravity are thrown farthest outwardly toward the periphery of the chamber, whereas particles of least specific gravity fall closest to the axis of the chamber and the distance of separation between lightest and heaviest particles for any given cup speed will depend upon the degree of variation in specific gravity of the particles in the stock. However, the degree of separation effected in this manner can be increased materially by the mild in ward movement of air as described above, by virtue of the fact that particles of low specific gravity will be carried a greater distance toward the axis of the chamber by the in-flowing air, than will particles of greater specific gravity, thereby widening the degree of separation. Incidentally, the controlled air currents through the projected shower further aid in the ultimate separation by carrying off with the discharged air some of the extremely fine particles such as flour dust and the like in the middlings.

The radial baffles 16 do not interfere with the downward and inward and upward and inward movement of air as above described, but are very effective in preventing rotary movement of air withing the casing, thereby preventing the setting up of disturbing eddy currents which would otherwise be produced by rotation of the upper table and the higher speed rotation of the rotary cup or sprayer head, and which eddy currents, if permitted to exist, have a very degenerating efiect on the separating action of the machine. It will, of course, be understood that rotating eddy currents would tend to re-mix the lighter with the heavier particles, and thereby defeat the very purpose of the machine. Radial deflector plates have been found to contribute materially to the improved results obtained by this machine.

What is claimed is:

1. In a machine of the kind described, a casing, and within said casing a rotary upper table and a non-rotary lower table, said upper table having concentric grading channels and intervening imperforate table surfaces and depending sweepers, said lower table having concentric discharge-port-equipped trough-like receivin channels, the latter underlying and receiving from the overlying grading channels of said upper table, and in which receiving channels the sweeper blades of said upper table are arranged to travel to deliver the materials to said discharge ports, and means in the upper portion of said casing for producing a shower of materials to be separated.

2. In a machine of the kind described, a casing, and within said casing a rotary upper table and a non-rotary lower table, said upper table having concentric grading channels and intervening imperforate table surfaces and depending sweepers, said lower table having concentric discharge-port-equipped trough-like receiving chan-.

to deliver the materials to said discharge ports, means in the upper portion of said casing for producing a shower of materials to be separated, and deflectors supported in said casing and working immediately over the imperforate table surfaces of said upper table.

3. In a machine of the kind described, a casing, and within said casing a rotary upper table and a non-rotary lower table, said upper table having concentric grading channels and intervening imperforate table surfaces and depending sweepers, said lower table having concentric dischargeport-equipped trough-like receiving channels, the latter underlying and receiving from the overlyin grading channels of said upper table, and in which receiving channels the sweeper blades of said upper table are arranged to travel to deliver the materials to said discharge ports, means in the upper portion of said casing for producing a shower of materials to be separated, deflectors supported in said casing and working immediately over the imperforate table surfaces of said upper table, and means for adjusting said deflectors transversely of said table surfaces.

4. The structure defined in claim 1 in further combination with a supporting bracket secured to the interior of said casing and extending radially inward, and deflectors independently pivoted to said bracket and overlying the respective table surfaces of said upper table.

5. The structure defined in claim 1 in further combination with a supportin bracket secured to the interior of said casing and extending. radially inward, and deflectors independently pivoted to said bracket and overlying the respective table surfaces of said upper table, and operating connections to said deflectors extended to the exterior of said casing and terminating in manually engageable elements independently exposed at the exterior of said casing.

6. The structure defined in claim 1 in further combination with a supporting bracket secured to the interior of said casing and extending radially inward, and deflectors of the V or wedge type independently supported above the respective table surfaces of said upper table and mounted for independent adjustments transversely of said table surfaces.

'7. The structure defined in claim 1 in further combination with a supporting bracket secured to the interior of said casing and extendingradially inward, and deflectors of the V or wedge type independently supported above'the respective table surfaces of said upper table and mounted for independent adjustments transversely of said table surfaces, said deflectors being pivotally connected to said supporting bracket and having operating connections'extended to' the exterior of the casing.

'8. The structure defined in claim 1' in further combination with a supporting bracket secured to the interior of said casing and extending radially inward, and deflectors of the V or wedge type independently supported above" the respective table surfaces of said'upper table and mounted for independent adjustments transversely of said table surfaces, said deflectors being pivotally connected to said supporting bracket and having operating connections extended to theexterior of the casing, said operating connections including thrust bars extended to the exterior of the casing, rockers pivotally mounted outside of said casing, and operating knobs having'screw and nut connections to said rockers for oscillating the same and independently-adjusting the said deflectors.

9. In a machine of the kind described, a casing,

and within said casing a rotary upper table and a non-rotary lower table, said upper table having concentric grading channels and intervening imperforate table surfaces and depending sweepers, said lower table having concentric dischargeport-equipped trough-like receiving channels, the latter underlying and receiving from the overlying grading channels of said upper table, and in which receiving channels the sweeper blades of said upper table are arranged to travel to deliver the materials to said discharge ports, and means in the upper portion of said casing for producing a shower of materials to be separated, the gradin channels of said upper table having depending flanges that work within the troughlike channels of said lower table.

10. In a machine of the kind described, a casing, and within said casing a rotary upper table and a non-rotary lower table, said upper table having concentric grading channels and intervening imperforate table surfaces and depending sweepers, said lower table having concentric discharge-port-equipped trough-like receiving channels, the latter underlying and receiving from the overlying gradin channels of said upper table, and in which receiving channels the sweeper blades of said upper table are arranged to travel to deliver the materials to said discharge ports, and means in the upper portion of said casing for producing a shower of materials to be separated, the grading channels of said upper table having depending flanges that work within the troughlike channels of said lower table, the sweepers of said upper table being in the form of blades extended downward between the flanges of the grading channels of said upper table and into the trough-like channels of said lower table.

11. The structure defined in claim 1 in further combination with secondary sweepers in the form of clean-out brushes mounted on and carried by said upper table and movable, at will, into and out of the trough-like channels of said lower table.

12. The structure defined in claim 1 in which the sweepers of said upper table are circumferentiall spaced on said upper table so that a plurality thereof work in each trough-like channel of the lower table.

13. In a machine of the kind described, a casing, an upright air circulating stack rigidly supported at the axis of said casing, and within said casing a rotary upper table and a non-rotary lower table, said upper table having a hub journaled on said stack, said upper table having concentric grading channels and intervening imperforate table surfaces and depending sweepers, said lower table having concentric dischargeport-equipped trough-like receiving channels, the latter underlyingv and receiving, from the overlying grading channels-of saidupper table, and in which receiving channels the sweeper blades of said upper table are arranged to travel, and a spreader cone mounted on and rotatable with the hub of said upper table and closely engaging said stack, said stack having air intake ports at its upper portion.

14, In a machine of the'kind described, a-casing, an upright air circulating stack rigidly supported at the axis ofv said casing, and within said casing a rotary upper table and a non-rotary lower table, said upper table having a hub journaled on said stack, said upper table having concentric grading channels and intervening imperforate table surfaces and depending sweepers, said lowertable having concentric discharge-' port-equipped trough-like receiving channels, the latter underlying and receiving from the overlying grading channels of said upper table, and in which receiving channels the sweeper blades of said upper table are arranged to travel, a spreader cone mounted on and rotatable with the hub of said upper table and closely engaging said stack, said stack having air intake ports at its upper portion, and a tubular baffle surrounding and spaced fromthe upper port-equipped end of said stack.

The structure defined in claim 14 in which said tubular baflie has radially spaced air passages and is connected to said non-rotary air circulating stack.

16. The structure defined in claim 13 in further combination with a high speed spindle extended axially upward through said stack and provided at its upper end with a discharge head for producing an approximately semi-spherical shower of materials above said air stack and upper table.

17. The structure defined in claim 14 in which said tubular baflie is secured to the upper portion of said air circulating stack and in which the upper end of said stack has air intake passages in direct communication with the interior of said baflle.

18. The structure defined in claim 1 in further combination with a spreader cone mounted on said upper table, a fixed air stack extended axially upward through said tables and on which said upper table is journaled, a high speed spindle extended axially upward through said air stack and provided at its upper end with a discharge head arranged to discharge a substantially semispherical shower of materials over and around said spreader cone and onto said upper table.

19. In a machine of the kind described, a casing, and within said casing a rotary upper table and a non-rotary lower table, said upper table having concentric grading channels and intervening imperforate table surfaces and depending sweepers, said lower table having concentric discharge-port-equipped trough-like receiving channels, the latter underlying and receiving from the overlying grading channels of said upper table, and in which receiving channels the sweeper blades of said upper table are arranged to travel to deliver the materials to said discharge ports, a fixed tubular stack extended axially upward through said tables and on which said table is journaled, a high speed spindle extended axially upward through said stack and provided at its upper end with a discharge head adapted to project a substantially semi-spherical shower of the materials onto said upper table.

20. In a machine of the kind described, a casing, and within said casing a rotary upper table and a non-rotary lower table, said upper table having concentric grading channels and intervening imperforate table surfaces and depending sweepers, said lower table having concentric discharge-port-equipped trough-like receiving channels, the latter underlying and receiving from the overlying grading channels of said upper table, and in which receiving channels the sweeper blades of said upper table are arranged to travel to deliver the materials to said discharge ports, a fixed tubular stack extended axially upward through said tables and on which said table is journaled, a high speed spindle extended axially upward through said stack and provided at its upper end with a discharge head adapted to projecta substantially semi-spherical shower of the materials onto said upper table, a spreader cone anchored at its lower end to said upper table, inward of its innermost grading channel, and closely engaging said stack at its upper end.

21. In a machine of the kind described, a casing, and within said casing a rotary upper table and a non-rotary lower table, said upper table having concentric grading channels and intervening imperforate table surfaces and depending sweepers, said lower table-having concentric discharge-port-equipped trough-like receiving channels, the latter underlying and receiving from the overlying grading channels of said upper table, and in which receiving channels the sweeper blades of said upper table are arranged totravel to deliver the materials to said discharge ports, a fixed tubular stack extended axially upward through said tables and on which said tab-le is journaled, a high speed spindle extended axially upward through said stack and provided at its upper end with a discharge head adapted to project a. substantially semi-spherical shower of the materials onto said upper table, a spreader cone anchored at its lower end to said upper table, inward of its innermost grading channel, and closely engaging said stack at its upper end, and a non-rotating tubular baffle surrounding and spaced from the upper portion of said stack, and over which tubular baflie a shower of material is projected by said discharge head.

22. The structure defined in claim 19 in further combination with a spreader cone closely engaging said stack at its upper end and at its lower end extending over that portion of said lower table that is radially inward of its innermost grading channel.

23. Th structure defined in claim 19 in further combination with a spreader cone closely engaging said stack at its upper end and at its lower end extending over that portion of said lower table that is radially inward of its innermost grading channel, and a tubular baflie concentrically spaced around and outward of the upper portion of said stack, said bafile having circumferentially spaced air passages leading thereinto.

2 1. The structure defined in claim 19 in further combination with circumferentially spaced baffle blades in the upper portion of said casing overlying said upper table and extended radially outward from the projected axis of the latter.

25. The structure defined in claim 21 in further combination with baiile'blades anchored to and projecting radially outward from said tubular baflie and overlying said upper table below the top of said casing.

26. The structure defined in claim 21 in further combination with circumferentially spaced baiile blades projected radially outward from the tubular bafile and supported thereby in substantially upright positions.

27. The structure defined in claim 19 in further combination with a spreader cone closely engaging said stack at its upper end and at it lower end extending over that portion of said lower table that is radially inward of its innermost grading channel, a tubular air bafile concentrically spaced around and outward of the upper portion of said stack, said tubular baiile having circumferentially spaced air passages leading thereinto, and bafile blades anchored to and projecting radially outward from said tubular b aille.

28. The structure defined in claim 1 in further combination with a secondary wiper including to carry said brush-acting secondary wipers into and out of the channels of said upper and lower tables, and means for oscillating said rock-shaft including a radial arm on said rock-shaft, an oscillatory trip mounted on a relatively stationary part and movable into and out of the path of movement of the arm of said rock-shaft.

30. The structure defined in claim 21 in which said casing is provided with a substantially semispherical dome formed with circumferentially 19 paced air intake ports.

LEONARD JOHNSON. MARTIN A. RIEMAN.