US2713977A - Milling apparatus for grains and other materials - Google Patents

Description

H. A. NOLL July 26, 1955 MILLING APPARATUS FOR GRAINS AND OTHER MATERIALS Filed DEC- 29, 1950 3 Sheets-Sheet l 7 r a Z8 A 3 1 3 m J a a v 7 j A 2 W13 7 WI Hi 7 r m Q. 3 a 8 5 V 5 3 2B 3 a A \H 7 Z x c 3 & 19. Nail.

5 Sheets-Sheet 2 H. A. NOLL Z rzd erziafl in r July 26, 1955 MILLING APPARATUS FOR GRAINS AND OTHER MATERIALS Filed Dec- 29, 1950 July 26, 1955 H. A. ou.

MILLING APPARATUS FOR GRAINS AND OTHER MATERIALS 5 Sheets-Sheet 3 Filed Dec. 29, 1950 United States Patent ()fiice 2,753,937 Patented July 2 5, 1955 MlLLING APPARATUS iron; GRAINS AND oTHEn MATERIALS Heinrich A. Noll, Dusseldorf, Germany, assignor to H. H.

and H. Manufacturing Co., Chicago, Ill., a corporation of Illinois Application December 29, 1950, Serial No. 203,491 6 Claims (Cl. 24179) This invention relates to milling methods and apparatus particularly adapted for producing flour from grains, especially wheat, but also of value in the grading and selective separation'of other materials including dyestuffs.

In the interests of convenience and simplification of disclosure, the processingflthe apparatuses and the system .1

separating and purifying units employ a number ofscreens zor sieves of different mesh fineness which are agitated or vibrated in various manners and by suitable mechanisms to effect selective separations. Such sieving or screening devices, commonly known as plane sifters, are

expensive to manufacture, to install and to operate and their maintenance costs are relatively high. Furthermore the vibrating sifters, when loaded, are very heavy indeed and when agitated or vibrated, frequently shake their supporting structures including the buildings in which they are housed. Usually also it is necessary to aid the sifting or screening operation by employing brushes, wipers or scrapers to move over the screen or sieve surfaces to force the particles of ground material through the mesh openings in the screen or sieve as well as to clear away those particles of a size too large to be forced through the mesh openings, the result being that the sieve or screen material is soon worn out therefore requiring frequent replacement. In addition such prior art apparatuses require extensive floor space and substantial supporting structures, all of which is to say that the magnitude of the equipment and structures required and the expense entailed makes it difficult if not impossible for the small operator to enter the business especially if his operations and market are morelor less localized and restricted.

Plane sitters and present day operating methods connected therewith involve a number of other disadvantages, Where, for, instance, a mill is designed to produce a high capacity of. finely ground material such as cereal flour, itis necessaryto provide a tremendous or what may be said to be an apparently disproportionate number of plane sifters, centrifugal separators and related apparatuses relative to the grinding or crushing machinery capacity and the product quantity produced. Moreover,

clogging of a screen may require a shut-down of the mill or of the sifter at least, with consequent losses, and when the number of plane sifters and screens increases, the number of such delays and the total loss becomes extrern ely serious,

The main objects of this invention, therefore, are to provide an improved method, system and sifting or separating apparatus for securing the sequence ofoperations essential "to extract from ground materials such, for

instance, wheat, those finely cornminuted particles of predetermined sizes which may be required for a marketable product of high and uniform grade; to provide an improved sifting method, system and apparatus which utilizes suction not only to convey the ground grain or other material from a grinder or crusher to the sifters and separating units but also to effect all or substantially all of the sifting, separating and purifying steps to produce flour and intermediate products from the comminuted grain; to provide an improved method, system and apparatus of this kind requiring no agitating or vibrating machinery for the screens or sieves and having a minimum of parts, hence capable of being inexpensively manufactured and economically maintained while susceptible of various adaptations so as to be especially available to the small flour producing operator; and to provide equipment of this kind having an improved arrangement of screen sieves and a pump or blower and a collector with conduits connecting these pieces of apparatus whereby there may be a continuous flow of material into the grinder and from the. grinder discharge on through the various apparatuses which effect separation of the various grades or sizes of the ground particles and delivery of them to suitable places for collection.

Fig. 2 is a sectional view in elevation of a preferred form of separator or sieving device which may be employed in carrying out this invention; Fig. 3 is a transverse sectional view of the apparatus shown in Fig. 2, the view being taken substantially along the section line 33 of Fig. 2;

Fig. 4 is a sectional view in elevation of a modified form of separator or sieving device which may be used in carrying out this invention;

'Fig. 5 is a sectional view in elevation of another modified form of separator or sieving device;

Fig.6 is a transverse sectional view of the latter taken on the line 6-6 of Fig. 5;

Fig. 7 is a sectional view in elevation of still another modified form of separator;

Fig. 8 is a sectional view in elevation of the separator of Fig. 7, the view being taken on the line 88- of Fig. 7; and i Fig. 9 is an enlarged, fragmentary detail showing, as respects the modified form of separator shown in Fig. 7, the manner in which the screen fabricmay be stretched and held in place on a rotating ring. One of the principal features of the invention, broadly speaking, involves the employment of differential pressures to eifect the movement of materials from the time they are ground to the end of the separating or sieving and settling or collecting steps in a milling process. However, it is to be understood that the expression differenti'al pressure as used herein is intended to include the creation or tendency toward creation of a lesser pressure at a definite place or places within the system by positive means, such as a pump, causing or tending to cause a pulling or drawing or suction effect to be applied to the air or other gas or fluid and the materials entrained therein and carried thereby within the system or some part thereof, as distinguished from a mere pushing" or pressing force alone driving or tending to drive the material and its fluid carrier into or through the systern or some part thereof. it should also be understood, of course, that a combination of pulling and pushing forces i. e. differential pressure created by both a force pump action and a suction pump action, is within the intended meaning of the expression as used herein. In the illustrated embodiments of the invention one or more suction pumps or blowers in the system serve alone or with the addition of such positive pressure as may be created by other means, as, for instance, a force pump, or a grinder of the type disclosed in my Patent No. 2,651,471, dated September 8, 1953, to pull or draw the ground material from a grinder or crusher and through all of the system including sieves or sitters and to and including a centrifugal separator.

In the illustrative embodiment of Fig. 1, there is a rinder or crusher A which may be of the type disclosed in my said patent, a separator or sievin apparatus B, a centrifugal separator or settling chamber C, a pump or blower D, and a collector E. The grinder, the separator and the pump or blower have moving parts which are driven by or from any suitable source of power. Materials ground in the grinder A are discharged therefrom into a conduit 11 in which there may be a sight glass 12 for inspection purposes and which leads to the inlet 13 of the separator or sieving apparatus B. Material passing through the sieving apparatus B flows through the outlet 13' into a conduit 14 which carries it into the centrifugal separator C which may be of any usual construction, where those heavier and coarser particles which have passed the sieves or shifter screens in separator B, are deposited and removed by the combined effects of centrifugal force and gravity while the lighter and finer particles are carried on through a conduit 15 to the pump or blower D and thence are forced through conduit 16 into a filter bag or other collector E. All or a major part of the force required to effect the transportation of the ground material as well as its separation into selected parts may be supplied by the pump or blower D but such force may be supplemented, if desired, by the fanning or blower effect of a grinder, such as that of said Patent No. 2,651,471, or by the introduction of another pump or blower in the system between the separator or sieving apparatus B and the collector or filter-collector E as, for instance, in the conduit 14.

The separator or sieving apparatus B comprises a housing or vessel having relatively cylindrical side walls 17 and its axis extending in a vertical direction, a conical cap 18 closing its top and effecting connection with the conduit 11, a conical bottom cap 18' closing its bottom end and etfecting connection with the conduit 14, a plurality or series of non-vibrating or non-vibratory sieves or screens generally designated 19, a set of vanes, sweeps or the like generally designated 21 which may carry or represent scrapers, wipers, brushes or the like, and mechanism, including shafts 22, 23, gearing 24 and a pulley or other device 25', whereby power may be transmitted to rotate either the screens 19 or the vanes 21. The shaft 22 may be mounted in suitable bearings, thrust and radial 26, 27, carried by spider supports 28, 29 secured in the housing. The shaft 23 may be supported in bearings 31, 32 carried by a housing 33 which may also shield the shaft and gearing from material entering the top of the separator.

Preferably, the sieves or screens 19 are successively of smaller or finer mesh from top to bottom so that all but the largest or most coarse particles of material may pass the top screen or sieve, each successively lower screen passing smaller or finer particles than the screen immediately thereabove and retaining particles too large or coarse to pass. In order to prevent accumulations of coarse or non-passing material particles from retarding or blocking the flow of other particles susceptible of passing the screens and to move such coarse particles in each grade of particle size from the upper surfaces of the screens for further grinding or other purposes, the sepachute structure.

rator is equipped with a series of chutes diagrammatically illustrated at 34 in Fig. 1 and designated 34 in Fig. 2 since they represent somewhat different arrangements. The separator of each of Figs. 1 and 2 employs rotary sweeps or vanes, rotation thereof being effected by the shaft 22 to which they are attached, while the screens are suitably secured to the housing against movements relative thereto but are cut away over the chutes to permit the sweeps or vanes 21 to move or sweep the coarse screenings into the chutes as will be understood.

Chutes 34 (Fig. 1) are illustrated as connected with and emptying into a series of bins, compartments or the like 35. Valves in these bins or compartments (a valve stem 36 in Fig. l symbolizing such valves) control the flow of material particles therefrom into conduits 37 which join at a header 38 the flow from which into a single discharge conduit 39 may also be controlled by a valve. Preferably, the valves in the bins 35 are selectively operable so that material particles may be released individually or in any desired combination and proportions with material particles from any other bin or bins. Some or all of the material collected in bins 35 may be returned to the grinder or other disposition may be made of it.

The discharge chutes 34' illustrated in Fig. 2 provide for direct discharge of material screenings swept from the top of the screens but because the system is under low pressure by reason of pump D, it is necessary to prevent air from entering the system and to that end each chute is equipped with a pair of valves 41 hinged at 42 to the Accumulation of a given weight of material behind the valves 41 will cause the valves to open outwardly to permit such material to flow out of the chutes into bags or other receptacles. Valves 41, being so disposed and mounted, are readily closed by gravity and pressure of air trying to enter, thereby elfectively cutting off the fiow of air into the system through the chutes while permitting the relatively free flow of material out of the chutes. As will be appreciated, spring or adjustable weight means may also be employed to close the valves or to supplement the action of gravity and air pressure; means for opening and closing these valves by hand may also be employed.

Screenings may accumulate behind the innermost valve 41 until their weight is suflicient to overcome the forces holding such valve closed whereupon the valve may open and permit the screenings to flow in behind the outermost valve which is in closed position to prevent the entry of air. After a predetermined quantity of screenings has flowed from behind the inner valve to relieve the pressure it will close or tend to close. However, if the inner valve has not closed at the time the outer valve is pressed open by the weight of material accumulated behind it and the material is discharged, the inner valve will be closed by the pressure of the outside air.

As shown in Fig. 2, it may be desirable to equip the vanes or sweeps 21 with brushes 43 or other devices to make contact with the upper surfaces of the screens or to approach close to the screen surfaces in order to clear away the screenings so that the suction created by the pump or blower D may be fully effective to draw the finer material through the screens. It may also be desirable to be able to observe operations within the separator and to have access to each screen section therein. To that end the housing may be provided with glassed doors or windows 44 and the interior may be lighted by electric lamps 45. In order to effect removal and replacement of screens and sweeps or vanes as well as for other purposes, the housing or casing 17 may be made with hinged quadrants 46 and 47 normally latched tightly together by fastening mechanisms such as indicated at 48 in Fig. 3.

While the separators or sifters of Figs. 1 and 2 show fixed screens and rotating sweeps or vanes, the modified types of Figs. 4 and 7 employ rotating screens, the type of Fig. 4 employing a stationary or fixed vane or a plurality thereof, one vane being shown each of the screen; ing compartments just above the s ho wing Qffth ChlllZC for, such cpmpa rtmen t, the construction and arrangement being otherwise similar to those above described. The type of Fig. 7 is designed for horizontal instead of vertical flow of the material stream. Referring more particularly to Figs. 7, 8 and'9, a housing or casingj4l of, generally cylindrical, shape with its axis' herizontal carries a plurality of pairs of spaced g me e; between. each pair of hich s wate cre n or s ev ifi man e at sj' on a driven shaft and at its circumferential edge in clamp rings S L Suitablyeuppor tedin theupper portion of each except the last of the compartments formed by the rotaryjscreens 53 isa cone-shaped nozzle 55, each nozzle, being inlaxiallline with the others and, inturn, in. line. with an inl et conduit 56 and an. outlet conduit 57. Thelower sidev of eachcompartrr ent opens into a chute or bin58 which rnay b e val ved" at itsbottorn endfor. removal of screenings accumulating therein. The shaftf50, of course, is driven from any suitable source of power, the pulley.59, being representative of a power transmitting means. 7

The type of separator illustrated in Figs. 5 and 6 varies from the. othersprimarily in having. a housing or. casing 61 of rectangular. cross-section as viewed in Fig. 6 and in having a series of brushes, sweeps or wipers 62 extending transversely. of. an endless belt 63 carried over suitable rollers 64.mounted in the housing-above each screen or sieve 65, one of each pair of rollers being driven by suitable. transmission mechanism 67-from a source (Sf-power.

The centrifugal separator C maybe of anyusualtype well known on the marketand so may be the pump or blower D and collector The separator C may have a valved outlet- 7-1- at its bottom end and, similarly the collector E may have a valved outlet 81 Preferably the conduits H and'14-will be of relatively small diameter to provide a high velocity and low pressure to carry the particles of material flowing therethrough while the conduits 1 5 and 16 will be of substantially larger diameter to decrease the velocity with a consequent increase in pressure as willbe understood; The collector B will be constructed afterthe manner of the usual vacuum cleaner bags to retain the very fine flour dust whilepermitting the entrainedair to escape.

The operation of the system, so far as the conveyance of the ground grain or other material and the sieving or sifting in the screen separators are concerned, is sub stantially the same regardless of which type of separator is employed. If grain is the material to be made into a flour state, it is ground in the grinder or crusher A and discharged into the conduit 11 through which it is drawn by the suction created by the pump or blower D. The fluid stream of grain particles of varying degrees of fineness or size flows into the screen or sieve separator and onto the first sieve or screen which retains only the most coarse particles and passes all others, the suction or differential pressure created by the pull of the pump or blower D, being efiective to perform this separation rapidly and efliciently. The coarse particles retained by the first screen are removed by the sweeps or brushes, which may be operated continuously, and are delivered into the top chute. Of those particles which pass the top screen or sieve, the most coarse are retained on the top or upstream surface of the next and finer mesh screen or sieve and are similarly discharged into the chute provided to receive them, while all finer particles pass on to the next sieve or screen the mesh of which is still finer than the previous one where the process of separation of a coarse grade from all finer grades is eflected in a similar manner.

Those particles which pass the lowest screen or sieve, in the separators of the types shown other than that of Figs. 7 and 8, are drawn through conduit 14 and enter the centrifugal separator C at relatively high velocity.

Entering separator Cat the perimeter and in a tangential direction, the stream of air with entrained particles whirls around, the heavier particles being thrown outward of the whirling body and gradually sinking to the bottom,

the lighter dust going to the center and flowing upwardmaterial but passes all other material particles to the succeeding rotary sieve or screen through the next noz zle 55 so that the next increment of coarseness isremoved, the process continuing through the lastfscreenor, sieve. Material sifted or screened outby each screen falls under the action of gravity into the chamber or compartment ahead of such screen. and is removed. from time to time or as desired. If, preferred, a station ry brush equipped. vane maybe employed tov assist gra t'yf in removing the screenings from the s'creen surfa'ce, The last compartment, i. e. that one which is next adjacent to outlet conduit 57, may serve, substantially the 'saime purpose as the separator C, the fine dust flowing through. the pump or blower tocollector E. f

Many other variations and modifications may be de: vised and substantial changes in constructions, and ar rangements may be employedwithout. departingfrom the principles and other fundamentals of the.process, system and apparatuses disclosedherein. Consequently'fl desire to be limited only by theinventionspirit and the. scope ofthe appendedclaims. l

I claim:

l. A flour sifting, apparatus, comprising, ahousing hav ingan inlet and an. outlet and adapted to'be interposedin an airy suction conduit between a. source of comminuted material and a pump for drawing material frorn said out; let, a. plurality of rotatablev but nonvibrating screeens of successively finer. mesh in the, direction of flow spanning said housing across the path of. material flowing, from said inlet to said outlet, a downwardly and outwardly directed discharge chute for screenings leading out of said housing from the upstream surface of each screen, wiper means for directing screenings from said upstream surfaces into said chutes, and means for; eliecting, rotation of said screens.

2. A flour sifting apparatus comprising, a housing having an inlet and an outlet and adapted to be interposed in an air suction conduit between a source of comminuted material and means for creating a suction force at said outlet, a plurality of screens disposed in and transversely of said housing, a downwardly inclined screenings chute leading to the exterior of said housing from each of said screens, a pair of valve members hingedly mounted in spaced relation to one another in each of said chutes and normally urged to close the respective chute against the inflow of air from the exterior into said housing, said valve members being adapted to be successively opened by the accumulation of a predetermined quantity of screenings inwardly thereof, a screen-sweeping means associated with the upstream surface of each screen for relative movement over the surface thereof for sweeping the screenings therefrom into said chutes, and means including a shaft extending into said housing for eifecting relative rotation between said screen-sweeping means and the respective screens.

3. In a system of flour milling, a grinder mechanism having an inlet and an outlet for grinding material to be made into flour, a separator including a chamber having an inlet connected with the outlet from said grinder and an outlet therefrom, a plurality of successively finer screens arranged in spaced relation to one another within said chamber and across the flow path of material flowing from the chamber inlet to the outlet thereof, means for removing from the receiving side of each screen the material retained by such screen, a settling chamber having an inlet connected with said outlet from said separator chamber, and a blower having an inlet connected with said settling chamber outlet and having a discharge outlet, whereby material flow will be established in a path from said grinder through said separator and settling chamber to said blower in succession.

4. In a system of flour milling, a grinder mechanism having an inlet and an outlet for grinding material to be made into flour, a separator including a chamber having an inlet connected with the outlet from said grinder and an outlet therefrom, a plurality of successively finer screens arranged in spaced relation to one another within said chamber and across the flow path of material flowing from the chamber inlet to the outlet thereof, means for removing from the receiving side of each screen the mate rial retained by such screen, a settling chamber having an inlet connected with said outlet from said separator chamber, a blower having an inlet connected with said settling chamber outlet and having a discharge outlet, whereby material flow will be established in a continuous path from said grinder through said separator and settling chamber to said blower in succession, and a porous walled collector connected with the outlet from said blower for receiving material dust discharged to said blower from said settling chamber.

5. In a system of flour milling, a grinder mechanism having an inlet and an outlet for grinding material to be made into flour, a separator including a chamber having an inlet connected with the outlet from said grinder and an outlet therefrom, a plurality of successively finer screens arranged in spaced relation to one another within said chamber and across the flow path of material flowing from the chamber inlet to the outlet thereof, wiper means for removing from the receiving side of each screen the material retained by such screen, means for effecting relative movement between said screens and wiper means, a settling chamber having an inlet connected with said outlet from said separator chamber, and a blower having an inlet connected with said settling chamber outlet and having a discharge outlet, whereby material flow will be established in a path from said grinder through said separator and settling chamber to said blower in succession.

6. In a system of flour milling, a grinder mechanism having an inlet and an outlet for grinding material to be made into flour, a separator including a chamber having an inlet connected with the outlet from said grinder and an outlet therefrom, a plurality of successively finer screens arranged in spaced relation to one another within said chamber and across the flow path of material flowing from the chamber inlet to the outlet thereof, means for removing from the receiving side of each screen material retained by such screen, a settling chamber having an inlet connected with said outlet from said separator chamber, and a blower having an inlet connected with said settling chamber outlet and having a discharge outlet, whereby material flow will be established in a path from said grinder through said separator and settling chamber to said blower in succession, the connections between said grinder and separator and between said separator and said settling chamber being of restricted crosssection relative to the area of any of said screens whereby to maintain a high velocity flow of material to and from said separator relative to the velocity of flow through said screens.

References Cited in the file of this patent UNlTED STATES PATENTS 19,892 Woodward Apr. 6, 1858 236,844 Russell Jan. 18, 1881 257,252 Strasser May 2, 1882 284,488 Russell Sept .4, 1883 349,229 Lord Sept. 14, 1886 465,543 Shelley Dec. 22, 1891. 739,231 Snee Sept. 15, 1903 852,558 Heisel May 7, 1907 1,116,777 Williams Nov. 10, 1914 1,432,921 Swanson Oct. 24, 1922 1,530,193 Montgomery Mar. 17, 1925 1,560,910 I-launam Nov. 10, 1925 1,571,518 Foster Feb. 2, 1926 1,708,195 Stebbins Apr. 9, 1929 1,766,941 Prouty June 24, 1930 2,001,184 Cuppy May 14, 1935 2,144,418 Schramm Jan. 17, 1939 2,628,786 Piperoux Feb. 17, 1953 FOREIGN PATENTS 11,126 Great Britain of 1906 13,507 Great Britain June 17, 1899

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