US2931499A - Hydraulic separation system - Google Patents

Description

April 5, 1960 A. w. WAHLROOS EI'AL 2,931,499

HYDRAULIC SEPARATION SYSTEM Filed Oct. 1, 1953 2 Sheets-Sheet 1 \ZEF IN V EN TORS ARV/ 14 MHL Roos By Eowuv 7? C1. OCKER A -r ToRwE m- April 5, 1960 A. w. WAHLROOS ET AL 2,931,499

HYDRAULIC SEPARATION SYSTEM 2 Sheets-Sheet 2 Filed Oct. 1, 1953 INVENTORJ ARv/ l V. MHLRoos BY fowl/v 7S CLocKER 0 I WW ATTORNEYS 2,931,499 [Ce Patented Apr. 5, 1960 HYDRAULIC SEPARATION SYSTEM Arvi W. Wahiroos, Minneapolis, and Edwin T. Clocker, St. Paul, Minm, assignors to Archer-Daniels-Midland Company, Minneapolis, Minn., a corporation of Delaware Application October 1, 1953, Serial No. 383,533

17 Claims. (Cl. 209-12) This invention relates to an improved hydraulic system for separating particles of materials of different specific gravities and to a new and improved apparatus for carrying out the separation. More particularly the invention relates to an improved hydraulic system for cleaning grain by separating the lighter and heavier contaminating materials from the grain and to an improved grain cleaning apparatus.

Grain, as it comes from the field or from storage is usually contaminated both by material which is lighter than the grain, such as chalf, bits of husks and straw, weed seeds, insect fragments, rodent pellets and like light-weight foreign materials and by material which is heavier than the grain, such as sand, pebbles, bits of rock, glass, cinders, metal and the like. For convenience, hereinafter, these lighter contaminating materials will be referred to collectively as chaff and the heavier contaminants will be referred to as stones, although it is to be understood that other materials are included. Methods are known and apparatus is available for effecting separation of the very lightest and the very heaviest of these contaminating substances. These known means,

however, do not serve to effectively remove the contaminants which in their densities more nearly approach the specific gravity of the grain.

The term lighter as used in this specification and in the appended claims is meant to refer not only to the lesser weight or weight per unit volume of a contaminating body or particle, as compared with the weight or weight per unit volume of the wanted material, but also to the lesser velocity it would possess in free fall through a fluid. Similarly, the term heavier is meant to include not only the greater weight or weight per unit volume of a contaminating body or particle as compared with that of the wanted material, but also the greater velocity of that body or particle freely falling through a fluid. The terms thus encompass substances having approximately the same density as the grain or other wanted material but which have a shape which causes their hydraulic behavior to be different.

While this invention will be described with particular reference to grain, and specifically to wheat, it is to be understood that the applications of the principles of this invention are by no'means so limited. In addition to grains, the invention is also applicable to the hydraulic separation and cleaning of such materials as sand, pulverized coal, clays, suspensions of papermaking stock, various ores and minerals and the like. In addition to use in cleaning wheat the method and apparatus of this invention are likewise applicable to other grains such as barley, soybeans, rye, sorghums, oats, flax, peas, beans, peanuts and the like.

The principal object of this invention is to provide an improved hydraulic system of separating materials showing different hydraulic behaviors.

' Another object of this invention is to provide an improved hydraulic system of removing lighter and heavier contaminating materials from other wanted material.

It is another object of this invention to provide an improved hydraulic system of cleaning grain by rapidly separating the lighter and heavier foreign substances whereby excessive gain in moisture by the grain is prevented.

Still another object of this invention is to provide an improved hydraulic system of rapidly cleaning wheat by separating the chaff and stones therefrom without excessive gain in moisture.

A further object of this invention is to provide apparatus for separating materials showing different hydraulic behaviors.

It is a further object of this invention toIprovide an apparatus for hydraulically removing lighter and heavier contaminating material from other wanted material.

A still further object of this invention is to provide an improved grain cleaning apparatus for cleaning grain by hydraulically separating the lighter and heavier foreign substances. i v

Another further object of this invention is to provide improved hydraulic separating apparatus comprising a vertical column having an angularly disposed upwardly extending conduit and means for inducing an upward flow of liquid therethrough.

Other objects of this invention will become apparent as the description proceeds.

To the accomplishment of the foregoing and related ends, this invention then comprises the features hereinafter fully described and particularly pointed out in the claims, the following description setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principles of the invention may be employed.

The invention is further illustrated by reference to the drawings in which corresponding numerals refer to the same parts and in which:

. Figure 1 is a vertical elevational view of the hydraulic separator and cleaner which forms partof this invention;

Figure 2 is a transverse horizontal cross section taken along the line and in the direction of the arrows 22 of Figure 1 and showing the means for introducing the hydraulic fluid tangentially into the separating and cleaning system; and

Figure 3 is a diagrammatic and schematic representation of a cleaning or separating system of which the hydraulic separation system of this invention may form a part.

Broadly stated, this invention comprises a hydraulic system of separating particulate material having different hydraulic behavior characteristics by feeding the mixture of particulate material downwardly into the top of an upwardly moving column of water or other similar liquid whereby (l) the very lightest material remains on top of the liquid column and floats away, (2) the remainder of the material falls through a relatively quiet zone of liquid, the lighter portions of the particulate material being carried to the surface by the countercurrent flow of liquid, (3) the balance of the material meets a zone of moving liquid changing direction angularly upward, (4) the heaviest contaminating materials fall through this zone and are removed, (5) the wanted material now contaminated only by the lighter portions of the heavier foreign bodies changes direction angularly upward into a swirling upwardly moving column of liquid wherein (6) substantially all of the remaining contaminating material is thrown out and falls to the bottom of the column where it is removed and (7) the wanted material, now substantially free of heavier and lighter foreign bodies, is allowed to be washed out through the top of the angularly upward extending liquid column. The system which com 3 prises this invention embraces both a method of hydraulic separation and apparatus for carrying out that method. Depending upon the nature of the materials being separated or cleaned and the degree. and nature of the foreign bodies, the system of this invention may be used either alone, or in series with like separating means, or in combination with other separating or cleaning means of a diflerent nature. Thus, in Figure 3 of the drawings, the system of this invention is shown in use in combination with an auxiliary and complementary flotation separating or cleaning unit of a diflerent type which,

per se, is the subject matter of a copending application Serial No. 383,652 of Arvi W. Wahlroos, Russell J. Stenoerg and Jack W. Sigan filed of even date herewith.

Referring now to the drawings and particularly to Figure 1 there is here illustrated the hydraulic separator or cleaner which forms part of the instant invention. The apparatus comprises anelongated upright vertical generally cylindrical standpipe having an enlarged spout-like feeder inlet 11 at the top thereof and an upright angulariy disposed'cylindrical conduit 12 projecting from one side of the standpipe. The top of conduit 32; terminates somewhat short of the top of standpipe it) in order to maintain hydrostatic pressure within the conduit which is capped by reducing shoulder means 14 joined to flanged elbow 15 of reduced diameter for connection with further separating means or dewatering and drying means. The lower end of the standpipe 19 tapers inwardly at 16 to a short section of conduit 17 of decreased diameter containing a gate valve 18 and entering upon a collecting chamber 19 for stones and other heavy foreign bodies separated by the apparatus. mediate of the bottom of the standpipe and the angularly projecting conduit is a liquid inlet 2% (connected toa source of hydraulic fluid 21, as shown in Figure 2) tangentially intersecting the wall of the standpipe for introducing liquid into the standpipe and maintaining a constant swirling upward flow of liquid. Liquid inlet means 22 into the stone collecting chamber are provided for introducing water or other liquid for flushing the eavy foreign bodies out of the collecting chamber through conduit 24 and valve 25.

As shown in Figure 3, the grain or other material to be cleaned is fed by means of any conventional con veying means into a feed box 39 from which it is fed at a controlled rate through spout 31 into the feed inlet 11 of the standpipe. The standpipe 10 and its angularly projecting conduit 12 are filled with a swirling upwardly moving column of water or other liquid inert to the material being treated. As the material from the feeder box falls onto the top of theliquid column the very lightest chaff and like contaminating material is retained on the surface of the liquid and is floated off through line it in the direction of the arrow. The material being treated then falls through a relatively quiescent zone 19A of liquid in the top of the standpipe (above the sidearm 12) and the relative countercurrent flow of solid against liquid serves to separate more of the lighter foreign bodies and float them to the surface whence they are removed via line 50. The greater mass of the heaviest contaminants carries the pebbles and stones and the like down through dynamic zones 10B and 10C to the bottom of the standpipe 10 and into the collecting, chamber 19. After falling through the relatively quiescent zone MFA the material being treated enters into a. zone 16B and thence into zone 16C in which the liquid is moving upwardly in a swirling circular motion and is being diverted angularly into conduit 12 (in zone 1013). The material being treated entering into this moving zone or dynamic Zone 103 is carried off into the, angularly disposed conduit. The centrifugal action of the moving liquid in the dynamic zones 10B and 10C serves to throw out the remaining heavier contaminating substances against the walls of the conduit from where they fall to the bottom of the standpipe. The.

Inter-- enemas cleaned and separated grain or other material is then carried up with a swirling motion and then out through the top of sidearm conduit 12 and elbow 15 from whence it may flow through conduits 34, 35 and 36 to a conventional dewatering unit 37 and thence on through ducts 33 and 4t) (if drying is not required) or through ducts 38 and 39 to a conventional cyclone drier 41 fed by air from inlet 42 heated at heater 44- and vented out through vent 45 by vent fan '46. The dried wheat is recovered at cyclone discharge 47.

The floating chaff and other light contaminants are carried through duct Silt to screen 51 where the chaff is discarded and the liquid is discharged to the sewer or is recovered and carried through line 52 to recirculation tank 54 from where it is recirculated through lines 55 and 21 by means of pump 57 to inlet 2% of the vertical standpipe. The liquid from the dewatering unit may also be recirculated through lines 58 and 5% to the recirculation tank or discharged to the sewer as desired.

Alternatively, the separating unit of this invention may be used in conjunction with other hydraulic treating units depending upon the nature of the material being treated, the nature of the contaminants present and the like. In Figure 3 the hydraulic treating unit of this invention is shown in use in series with a complementary hydraulic flotation unit which, per se, is the subject matter of the above identified copending application filed of evendate herewith. It is to be emphasized, however, that the hydraulic separating and cleaning unit which is the subject matter of this application may also be used alone or in series with other like units as desired, and the combination shown in Figure 3 is for purposes of, illustration only.

In this combination the stream of liquid and material being treated from sidearm conduit 12 flows through conduit 3 to a surge tube 6% where make-up liquid is added through lines 61 and 62, if necessary. The slurry of liquid and particulate masses then flows through conduits 64, 65 and 66 into the flotation unit which comprises an upright vertical standpipe 67 containing a column of the hydraulic fluid, supplemented, if need be, from make-up 7 lines 61 and 69. In some cases, as where the slurry from conduit 12 is in a satisfactory state of dispersion, surge tube as may be by-passed and the stream fed directly to the flotation unit through conduits 34, 35, 63, 65 and 66. Conduit as enters the flotation unit axially through a cylindrical discharge outlet 68 at the bottom of the standpipe 67, the end of conduit 56 being disposed above this outlet axially in a cylindrical inlet 76 open at both ends. The slurry of material. being fed into the flotation unit surges up over the top edges of inlet '73 as shown by arrow NBA. and the wanted heavier material falls down through perforated conical hopper 71 as shown by arrows 7M3 into the discharge outlet $8 and out for dewatering and drying. The lighter contaminating material is carried by the upward flow of liquid out through the outlet '72 at the top of the flotation unit through line 74 to screen 51 and discard as shown by arrows 713C. The velocity of the upward flow of water in the upper portion of. the flotation unit is adjustable so as to effect the critical separation of the lighter contaminating bodies at this point. This adjustment of the liquid velocity iscarried out by means of a vertically movable conical member. 75 having an outlet 76 into outlet pipe "1'2 at the top ofthe flotation unit and adjustable by means of rod 78. The construction and mode of operation of the flotation unit are disclosed in more detail in the aforementioned copending application and are, so far as necessary to the understanding of this invention, incorporated by reference into the disclosure of this application.

Although it is to be. understood that the scope, of this invention is not limited thereto, the hydraulic separating.

and: cleaning system comprising this invention will now be further described withreference to its use in cleaning grain, and particularly wheat, with water being used. as;

the hydraulic fluid. An upright vertical generally cylindrical standpipe was formed approximately 6 feet long and .about 6 inches in diameiar with an enlarged tapering hopper-like inlet at the upper end thereof. intersecting the walls of this upright standpipe at about the middle thereofis a similar conduit about 6 inches in diameter and disposed upwardly at an angle of about 15 degrees from the vertical with the top of this branching conduit terminating in a 3-inch diameter conduit about one foot below the top of the standpipe. At approximately a foot from the bottom the wall of the standpipe is intersected by a tangential liquid inlet supply line 20. Water is introduced through this inlet at a nozzle velocity of from about three to five feet per second to give, for a six-inch diameter tube, an initial angular velocity of from 120 to 200 revolutions per minute. The upward velocity of the water in this case would be from about 0.2 to 0.5 feet per second. The tangential introduction of the water into the standpipe via line 20 results in the water having a circular motion and, When valves 18 or 25 are closed, a simultaneous movement upward, the design of the inlet nozzle being such that no vortexing occurs and the combined velocities do not permit the intermediate material to fall through into zone 10D. The water having the circular motion without vortex rises into the branch conduit 12 and leaves the apparatus through line 3-4. The circular or cyclonic action of the water continues as it rises in the branch tube. The water level in the vertical standpipe 10 is controlled by an overflow through conduit 50 and the rate of overflow is controlled by means of valves 33 in line 34 and 33A in line 35.

Wheat is then fed at a constant rate from feeder 30 through a spreader spout 3 1 and allowed to fall into the water. Floating chaff is carried away by the overflow through conduit 50 and the wheat falls freely through the rather quiet zone 10A at the top of the standpipe for a distance of about 1 /2 to 2 feet until it meets with the moving water in the upper part of dynamic zone 10B at the entrance to the branched conduit. Whilethe grain is falling freely through the counterc urrent flow of water in the relatively quiet zone 10A, the lighter contaminating bodies are washed free and carried back to the overflow and the heavier foreign bodies fall through zones 10B and 10C to the relatively quiet zone 10D at the bottom of the standpipe, through pipe 17 into the stone collector 19. 'Some of the wheat and the lighter stones, upon meeting the moving swirling column of water changes direction and passes up into the sloping branch conduit 12 and most continues to fall into the dynamic zone 10C of swirling water above the water inlet and begins to rotate with the water. The resulting centrifugal force causes the stones to move to the outside of the rotating mass until they reach the wall of the tube along which they are somewhat decelerated and fall to the bottom and out to the stone collector. This centrifugal separation continues as the rotating mass moves upward vertically through zone 10C and 10B and into the sloping branch conduit 12 where gravity aids in separation. The stones collecting in collector 19 may be flushed out by closing valve 18, opening valve 25 and introducing water through inlet 22 to flush the collector.

By reference to the rather quiet zone 10A, it will be understood that this portion of the liquid column is somewhat like a back-eddy, relative to the dynamic zone areas 10B and 10C. In conjunction with the feed-in of grain material, which tends to slow down and relatively stop the swirling motion of the upward flow of liquid, the very lightest chalf and like contaminating material is retained on the surface of the liquid to be floated off through line 50, as described.

The water and wheat are discharged from sloping conduit 12 into line 34 from which it may be subjected to further hydraulic treatment or passed to a dewatering unit. The wheat and water are introduced into the standpipe during the separating and cleaning stage insthe proportion of from about 2 to 15 parts by weight of water to each part by weight of wheat and preferably in the proportion of about 5.5 to 8 parts by weight of water to each part by weight of wheat with a ratio of 6 to 1 being optimum. The slope of the branched conduit 12 may vary from about 10 to 30 degrees from the vertical and preferably is about 15 degrees. Wheat is fed to a separator of the size described at a rate of from about 20 to 40 bushels an hour. In the normal operation of this hydraulic separator the actual contact time of the wheat with the water will be only from about 15 to 60 seconds. By maintaining this contact time between wheat and water at a minimum very littlewater is absorbed by,

the wheat and the wheat may be freed of water by de watering and drying without damage to its physical or chemical properties. The wheat, if dewatered immediately, will retain only from about 2 to 3 percent water as surface moisture and that can be removed by drying resulting in an overall moisture gain in the wheat of only a few tenths of a percent above its original moisture content. The use of a flash drier employing high initial air temperatures (550 F.) is possible since drying occurs by free evaporation.

The invention is further described by means of the following examples, these being illustrative only and not to be construed as a limitation upon the scope of the invention:

Example I Wheat was fed over aconventional (Sutton, Steele and Steele) dry stoning device and thereafter to a wet separating and destoning unit constructed as described in detail above at the rate of 30 bushel per hour. The wheat as it entered the dry destoner contained 41.7 grams of stone per pounds of wheat and upon leaving the dry destoner still contained 8.26 grams of stone per 100 pounds of wheat.

(Quantitative measurements of stone in wheat are made by floating a Weighed representative sample of the wheat upon a bath of carbon tetrachloride, separating and drying the stones which separate and then weighing.)

The wheat was then fed to the hydraulic separator of this invention at a rate of 30 bushels of wheat per hour. The conditions Within the separator unit were substantially as follows: Nozzle velocity at line 20 entrance to column 10:4 feet per minute; initial angular velocity of water in column 10=160 revolutions per minute; and upward velocity of water in column 10:0.35 foot per second. The ratio of water to wheat was approximately 6.5 to 1. This wheat after passing through the separarator unit and drying carried only 1.22 grams of stone per 100 pounds of wheat. Only 0.06 percent of the Wheat was carried through the separator to the stone collector and most of this could be recovered.

Example ll Wheat containing 23.8 gams of stone per 100 pounds of wheat was fed directly to the wet separator operated at a rate and under conditions similar to those in Example I. Only 0.855 gram of stone remained per 100 pounds of wheat, 96.4 percent of the stone being removed.

It is to be noted that a percentagewise expression of stone removal is misleading since highest percentage removals will be obtained with the highest contamination. Using the system of this invention stone content has been reduced to such an extent that on occasion only one and sometimes no stone particles would separate from a 25 pound sample of wheat floated on carbon tetrachloride.

Example III It will be understood that the dimensions and conditions recited above are given for a particular material (wheat) and for operation at a particularly capacity. Obviously, variations which will readily suggest themselves to persons skilled in this art may be made to adapt this invention to the treatment of different materials and at different rates.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that we do not limit ourselves to the specific embodiments herein.

What we claim is:

l. A hydraulic separator for Separation of materials of different densities and hydraulic behavior in an upwardly ascending and swirling liquid system comprising an elongated vertical liquid flow tube open at the top, an angularly disposed elongated upwardly extending branching material and liquid outlet flow tube intersecting said vertical tube intermediate of the ends thereof and liquid inlet pipe means tangentially intersecting said vertical tube intermediate of the bottom thereof and the said branching tube.

2. The separator according to claim 1 in which the upwardly branching tube is disposed at an angle from about 10 to 30 degrees from the vertical.

3. A hydraulic separator for separation of materials of different densities and hydraulic behavior in an upwardly ascending and swirling liquid system comprising an elongated vertical liquid flow tube open at the top, an angularly disposed elongated upwardly extending branching material and liquid outlet flow tube intersecting said vertical tube intermediate of the ends thereof and having a height less than the top of the vertical tube, valve means for regulating the liquid flow from said angularly disposed tube and liquid inlet pipe means tangentially intersecting said vertical tube intermediate of the bottom thereof and the said branching tube.

4. A hydraulic separator for separation of materials of different densities and hydraulic behavior in an upwardly ascending and swirling liquid system comprising an elongated vertical liquid flow tube open at the top, an angularly disposed elongated upwardly extending branching material and liquid outlet flow tube intersecting said vertical tube intermediate of the ends thereof having a top of reduced diameter and a height less than the top of the vertical tube, valve means for regulating the liquid flow from said angularly disposed tube liquid inlet, pipe means tangentially intersecting said vertical tube intermediate of the bottom thereof and the branching tube and means adapted for communication with a source of hydraulic fluid.

5. A hydraulic separator for separation of materials of different densities and hydraulic behavior in an upwardly ascending and swirling liquid system comprising an elongated vertical liquid flow tube, an enlarged opening at the top thereof, an angularly disposed elongated upwardly extending branching material and liquid outlet flow tube intersecting said vertical tube intermediate the ends thereof having a top of reduced diameter and a height less than the top of the vertical tube, valve means for regulating the liquid flow from said angularly disposed tube, pipe means tangentially intersecting said vertical tube intermediate of the bottom thereof and the branching tube, means communicating with a source of hydraulic fluid, valve means for regulating the flow of said fluid into said vertical tube and valve means adjacent the bottom of said vertical tube.

6. A hydraulic system for separating particular materials of different specific gravitics in an upwardly flowing liquid column comprising an elongated vertical tube adapted to contain an upwardly moving liquid column, a material feed means provided by an opening at the top of said vertical tube for feeding particular materials thereinto, an angularly disposed elongated upwardly extending branching material and liquid outlet flow tube intersecting said vertical tube intermediate the ends thereof having a top sectio'n of reduced diameter and a height less than the top of the vertical tube, valve means for regulating the outflow from said angularly disposed tube, pipe means tangentially intersecting said vertical tube intermediate of the bottom thereof and the branching tube for imparting a circular upward movement to at least part of the upwardly flowing liquid column, means communicating with a source of hydraulic fluid, valve means for regulating the flow of said fluid into said vertical tube, feeder means above the top of said vertical tube for introducing particulate material therein, valve means adjacent the bottom of said vertical tube for withdrawing heavier particles therefrom and means for removing the liquid from the intermediate density particles.

7. A system according to claim 6 further characterized in that the said branching tube is disposed at an angle from about 10 to about 30 degrees from the vertical.

8. A system according to claim 6 further characterized in that the said branching tube is disposed at an angle of about 15 degrees from the vertical.

9. A hydraulic system of separating particles of ma terials of different specific gravity which comprises introducing a liquid tangentially into the lower portion of an upright vertical liquid column having an angularly disposed upwardly extending liquid column branching therefrom whereby an upwardly moving swirling circular motion is imparted to at least part of the upright liquid column and the column branching therefrom, introducing the particles of material of different specific gravities downwardly into the top of the upright vertical liquid column, passing the particulate material downwardly through a relatively quiescent zone at the top of the upright vertical liquid column, into a zone of relative circular movement of the liquid and back upwardly through the circularly moving angularly disposed upwardly extending branched column whereby the lighter and heavier particulate material is separated and then removing the intermediate particulate material and separating the liquid therefrom.

10. A hydraulic system of separating particles of material of different specific gravity which comprises introducing a liquid tangentially into the lower portion of an upright elongated vertical liquid column having an angularly disposed upwardly extending elongated liquid column branching therefrom whereby an upwardly moving swirling circular motion is imparted to at least part of the upright liquid column and the column branching therefrom, introducing the particles of material of different specific gravities downwardly into the top of the upright vertical liquid column, passing the particulate material downwardly countercurrently against the upwardly moving vertical liquid column through a zone of relative quiescence at the top of the upright vertical liquid column, downwardly into a zone of relative circular upward movement of the liquid column and back upwardly through the circularly moving angularly disposed upwardly extending branching column whereby the lighter particulate material is separated by floating at the top of the vertical column and the heavier particulate material separated by centrifugal force and gravity, sinking to the bottom of the liquid column and then removing the intermediate particulate material and separating the liquid therefrom.

ll. The system according to claim 10 further characterized in that the mean angular velocity of the circularly moving liquid column is sufiicient to suspend and lift grain material into said circularly moving. angularly terized in that the upward velocity of the upwardly moving liquid column is from about 0.2 to 0.5 feet per second.

13. A hydraulic system of separating particles of materials of different specific gravities which comprises introducing said particles downwardly into an upwardly moving Y branched liquid column comprising an elongated vertical portion and an angularly disposed elongated upwardly extending portion branching therefrom, passing said particles downwardly countercurrently against the upwardly moving vertical liquid column through a zone of relative quiescence at the top of the vertical liquid column, downwardly into a zone of relative circular upward movement adjacent. the branching of the liquid column and back upwardly through the circularly moving angularly disposed upwardly extending, branching column whereby the lighter particulate material is separated by flo'ating at. the top of the vertical portion of the column and the heavier material is separated by centrifugal force and gravity, sinking to the bottom of the vertical portion of the column.

14. A hydraulic system of separating particles of materials of different specific gravities which comprises introducing said particles downwardly into an upwardly moving Y branched liquid column comprising an elongated vertical portion and an angularly disposed elongated upwardly extending portion branching therefrom, passing said particles downwardly countercurrently against the upwardly moving vertical liquid column through a zone of relative quiescence at the top of the vertical liquid column, downwardly into a zone of relative circular upward movement adjacent the branching of the liquid column and back upwardly through the circularly moving angularly disposed upwardly extending, branching column whereby the lighter particulate material is separated by floating at the top of the vertical portion of the column and the heavier material is separated by centrifugal force and gravity sinking to the bottom of the vertical portion of the column and maintaining said upwardly moving and circularly and upwardly moving portions of said column by introducing liquid tangentially into said column between the bottom of the vertical column and the branching thereof.

15. In a liquid system the method of continuously cleaning grain material of chaff, stones, and contaminants having different specific gravities and hydraulic behavior than the grain, the steps comprising a preliminary first step of effecting a mixture of the grain material and liquid and producing flow of the grain material in countercurrent relationship to an upwardly rising flow of liquid medium, hydraulically effecting separation of chaff and stones in the said first step, centrifugally effecting a flow of the liquid medium and carrying grain thereby into a vertical and inclined upward path, centrifugally and hydraulically effecting a separation of the grain from other contaminants having different hydraulic behavior, discharging the separated grain and liquid carrier from said upward inclined flow path, and subsequently effecting separation of the liquid medium from the grain.

16. In a liquid system, the method of cleaning grain material of contaminants by the process of substantially continuously treating grain containing contaminant materials in a plurality of sequentially countercurrent, centrifugal and concurrent liquid flows of removal of contaminants from the grain in substantially a combined first and second operation, the first stage comprising first introducing grain and contaminant materials into countercurrent, centrifugal and concurrent upwardly moving columnar liquid flows, effecting a separation and removal of a first portion of the contaminants from the grain material, directing a fluid flow of the grain material into the second stage, providing a water column and upward flow of fluid medium concurrently with the grain material in said second stage, providing a second concurrent fluid flow adjacent said water column and concurrent upward flow of said grain and fluid medium in said second stage, and controlling the relative velocities of the said adjacent concurrent fluid flows at such rates that in the first concurrent flow there is a travel of grain and contaminants therewith and in the second concurrent flow there is a countercurrent flow of grain material relative to a concurrent flow of fluid and contaminants, and substantially immediately effecting a separation of the grain from said liquid medium.

17. The. method of clearing a cereal grain material of contaminants of different weights and hydraulic behavior mixed therewith,v comprising the steps of introducing the cereal grain material andcontaminan'ts into a fluid body, effecting an initial separation of contaminants of lighter weight and lesser specific gravity than the grain material, removing the said initially separated contaminants, maintaining an upwardly rising and centrifugal fluid flow of suflicient velocity to suspend the grain material therein, diverting the said fluid flow and suspending grain material into a branching upwardly moving fluid flow path centrifugally, effecting separation of contaminants of heavier weight and greater specific gravity than the grain material in counterflow relationship to said diverted fluid flow and suspended grain material, and effecting a separation of the cleaned grain material from the said diverted fluid flow path.

Evans May 17,

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