US2624517A

US2624517A - Fluid current comminutor with cylindrical abutment impact target

Info

Publication number: US2624517A
Application number: US79860A
Authority: US
Inventors: Franklin S Smith
Original assignee: Individual
Current assignee: Individual
Priority date: 1949-03-05
Filing date: 1949-03-05
Publication date: 1953-01-06
Anticipated expiration: 1970-01-06

Description

n- 3 F. 5. SMITH FLUID CURRENT COMMINUTOR, WITH CYLINDRICAL ABUTMENT IMPACT TARGET 5 Sheets-Sheet 1 Filed March 5, 1949 INVENTOR Franklin 4S. Smzl/L BY fiiw QM ATTORNEYS Jan. 6, 1953 -F. 5. SMITH 2,624,517

FLUID CURRENT COMMINUTOR, WITH CYLINDRICAL ABUTMENT IMPACT TARGET Filed March 5, 1949 5 Sheets-Sheet 2 INVENTOR Flak/07in 5. b'mih ATTORNEYS Jan. 6, 1953 F, s; sMrr 2,624,517

FLUID CURRENT COMMINUTOR, WITH CYLINDRICAL ABUTMENT IMPACT TARGET Filed March 5, 1949 5 Sheets-Sheet 5 TTE1.4-.

H4 /39 I26 64b INVENTOR 'an/clin S. Snail/z ATTORNEYS Jan. 6, 1953 F. 5. SMITH FLUID CURRENT COMMINUTOR, WITH CYLINDRICAL ABUTMENT IMPACT TARGET 5 Sheets-Sheet 4 Filed March 5, 1949 Franklin 5. SmiZ/z ATTORNEYS:

Jan. '6; 1953 F. 5. SMITH ,6 7

- FLUID CURRENT COMMINUTOR, WITH CYLINDRICAL I ABUTMENT IMPAQT TARGET A Filed March 5, '1949 5 Sheets-Sheet 5 INVENTOVR Finn/61in S. Smith BY 1 53M qRw Patented Jan. 6, 1953 UNITED STATES PATENT OFFICE FLUID CURRENT GOMMINUTOR WITH CYLINDRICAL ABUTMENT ILIPACT TARGET 12 Claims. 1

This invention relates to impact milling apparatus.

One of the objects of this invention is to provide new and improved apparatus for impact milling. Another object is to provide apparatus of the above character which is simple, practical, and thoroughly durable. Another object is to provide apparatus of the above character, in which the particles of the milled product are classified in accordance with size. Another object is to provide apparatus of the above character in which the force of the impact may be readily controlled by the operator. Another object is to provide apparatus of the above character which is readily adaptable to milling products of different sizes and characteristics. Another object is to provide apparatus of the above character in which the classification of the sizes of particles from the milled product may be readily changed. Another object is to provide apparatus of the above character in which a maximum of cereal may be milled in a minimum of time. Other objects will be in part obvious and in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements, arrangements of parts, and in the relation and order of each of the same to one or more of the others, all as will be illustratively described herein and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings in which are shown one illustrative embodiment of the invention and a modification thereof:

Figure 1 is a side elevation of the milling apparatus, certain .parts being broken away for purposes of illustration;

Figure 2 is a top plan of the apparatus shown in Figure 1;

Figure 3 is a side elevation of the apparatus taken from the line 33 of Figure 1;

Figure 4 is a vertical section on an enlarged scale taken on the line 4-4 of Figure 2;

Figure 5 is a horizontal section taken on the line 5-5 of Figure 4;

Figure 6 is a perspective view on an enlarged scale of a portion of the target array;

Figure 7 is a horizontal section taken on the line 'l'! of Figure 6;

Figure 8 is a horizontal section taken on the line 8-8 of Figure 6;

Figure 9 is a vertical section on an enlarged scale taken on the line 99 of Figure 1;

Figure 11 is a vertical section taken on the line lll| of Figure 10;

Figure 12 is a vertical section on an enlarged scale taken on the line l2-l2 of Figure 10; and

Figure 13 is a perspective view on an enlarged scale of a portion of the target array used in the apparatus shown in Figure 11. g 7

Similar reference characters refer to similar parts throughout the several views of the drawmgs.

In general, the milling apparatus (Figure 1) includes a spout, generally indicated at 19, connected to a bin (not shown) containing the product to be milled. The nozzle [0a of spout [0 extends downwardly into a conduit l2 through which air is blown downwardly by a blower, generally indicated at M. The product to be milled, such as wheat, flowing from nozzle Illa is carried downwardly by the air stream passing through conduit l2 onto a conoidal member 15 (Figure 4), which together with a shell l8 positioned thereabove, forms nozzle 20, which directs the cereal into an array of spaced vertically positioned targets, generally indicated at 22. The product being milled disintegrates on striking the targets, the larger particles falling downwardly from the targets into a hopper, generally indicated at 24, and thence downwardly into chute 26. The smaller particles pass through the space between the targets into passageways 28 and 35 (Figure 5).

Passageways

28 and 30 increase in depth throughout their lengths, the smaller ends of the passageways being positioned on opposite sides of guiding vane 32, which splits the air stream and milled product passing through the target array into

passageways

28 and 30. Having passageways which increase in cross-sectional area throughout their lengths insures an even flow of the air stream into passageways 28 and 39 in all directions from nozzle 20 (Figure 4). The air streams in passageways 2B and 30 carry the particles which have passed through target array 22 around the outside of the target array to guiding plates I40 and I42, which direct the air streams into the tangential passageway 34 forming the intake of a cyclone collector, generally indicated at 36. Because of the constantly increasing size of both passageways, the air stream is slowed down so that the stream of air enters the cyclone collector at a velocity of fifty feet a second or less. The milled particles carried by the air stream into collector 36 fall into hopper 38, which is emptied into chute 40 by an air lock valve 42. The air in cyclone collector 36 passes upwardly through conduit &4 to the intake of blower I4, which recirculates most of the air entering the cyclone collector through the milling apparatus.

In detail, referring to Figures 3 and 4, the apparatus is supported by three hollow legs d, 52 and 54, the upper ends of which extend into sockets, such as socke 56 (Figure 4), in

brackets

58, 60 and 62 formed on housing (it. Housing 64 supports hopper 24, which in turn supports target array 22. Target array 22 includes a plurality of equidistantly spaced vertically positioned targets 22a mounted upon a framework including a wheel-shaped member 66 (Figures 4 and 5), a supporting ring 68 and a pair of retaining

rings

18 and 12. The upper and lower ends of each target are obliquely cut and fit in obliquely cut slots in the rim 66a of wheel-shaped member 66 and the lower surface of ring 68. Retaining rings 18 and I2, which prevent the targets from moving outwardly with respect to ring 68 and the rim 66a of wheel member 66, are maintained in spaced relationship with respect to each other by supporting members 74, Te, 78 and 80 (Figure 5), the upper and lower ends of which are positioned in recesses cut in rings 78 and 12 (Figure 6).

Supporting

members

74, 76, 18 and 86 are connected to retaining rings l8 and "E2, supporting ring 68 and the rim 66a of wheel 05 by means of taper pins, such as taper pins 82 and 84 (Figures 6 and 8) and rivets, such as

rivets

86 and 88. Rivet 85 secures the top end of supporting member 18 to retaining ring 12 and supporting ring 68, while rivet 88 secures the bottom end of supporting member I8 to retaining ring I8 and connects the latter to the rim 66a of wheel-shaped member 66.

It will be noted that the inner surface of each supporting member lies in a plane which is tangent to the outer surface of the target array 22, so that as

passageways

28 and 30 are followed to the right toward chute 34 (Figure 5) the passageway 15 (Figure 7) between the inner surface of each supporting member and the target array constantly increases. This causes the milled particles passing through the target array opposite supporting members M, 16, 78 and 80 to flow with the air stream to the right (Figure 5) into

passageways

28 and 38 and thus prevents them from clogging the space between the supporting members I4, 16, 1B and 80 and the target array.

Targets 22a are of rectangular shape in cross section and are preferably made of a molded abrasive, such as silicon carbide. When their upper and lower ends are positioned in the milled slots in the rim of wheel member 66 and supporting ring 88, a removable retaining ring 98 (Figure 4) is used to hold the upper ends of the targets in place on the target supporting framework. When ring 90 is removed, it is a simple matter to reverse the position of the targets 1: their inner edges are worn, or to replace them. In order to make the target array accessible for purposes of both cleaning and repair, the hopper 24 on which the target array is mounted (Figures 1 and 4) may be moved downwardly with respect to the apparatus. To accomplish this, hopper 24 is provided with a flange 24a (Figure 4) extending outwardly from its upper edge. Flange 24a has a seat 92 formed therein to receive the lower outer edge of the framework of target array 22. A locating pin 9-. (Figures 4 and 5) is provided in seat 92 and coacts with a notch 10a in retaining ring IE! to insure that the target array will always be correctly positioned in the apparatus if it is removed therefrom. Flange is also provided with outwardly extending portions, in the outer ends of which are formed recesses I82, I84 and I86 (Figure 5) in which

legs

56, 52 and 5d are positioned. To aid

legs

52, 52 and 54 in guiding hopper 2 as it is moved upwardly, the lower end of hopper is provided with an outlet chute connection H2 which fits chute 25 with a sliding fit. Thus, as hopper 2 moves upwardly and downwardly with respect to the apparatus, it is guided by

legs

52 and 54 and chute 28.

To aid the operator in lower-i hopper 2 1, it is counterbalanced by means of counterweights positioned in legs 5;! and 54. Referring to Figures 1, 3 and l, sprocket wheels H4, H6 and H8 are rotatably mounted on flanges, such as flanges 58a and (Figure 3) extending upwardly from brackets S3 and 62, respectively. As the counterweight assembly associated with each sprocket wheel is substantially similar, detailed description will be limited to the assembly associated with sprocket wheel Il (Figure 4). The sprocket chain I25, which runs over sprocket wheel H4, extends through a hole 222 in frame 64 and has one end I2Qa secured to frame 64 by means of a pin IN. The other end of sprocket chain IE8 passes downwardly through a hole I23 in bracket 58 into the interior of leg 59 where it is connected to the upper end of counterweight I68 (Figure l). The combined weight of the target array 22, member and hopper 24 is greater than the combined weight of the counterweights, in

legs

58, 52 and 54, and thus when the studs I28 (Figures 1 and 3) which connect hopper 24 to housing (i i are removed, the hopper assembly moves downwardly to the dotted line position shown in Figure 4. At this time, the target array may be removed, if desired, for purposes of repair or cleaning and also it will be noted that at this time the conoidal member I5 and the complete interior of housing G4 are accessible for cleaning and the target array and conoidal member may be removed if desired. The bottom surface 64d (Figure l) of housing 64 is provided with a gasket I29 mounted in a groove E39. Thus, when hopper flange 2 3a is drawn into contact with surface gasket E29 seals this connection.

As described above, the air from blower I4 passes downwardly through conduit I2 and encounters the product to be milled, such as grain, flowing downwardly from nozzle I00. to spout I8. At this point, the air stream picks up grain in conduit I2 to increase its speed and carries it downwardly against conoidal member l6 (Figure 4). Member I6 is detachably mounted on a pin I320. on the upper end of a support I32, the lower end I32b of which is positioned in a hole I34 in the hub 66b of wheel-shaped member (38. Conoidal member I8 is a conoid, the upper surface of which from its axis to its periphery is cycloidal. A shell I36 is connected by a flange IBM to a flange I2a on the lower end of conduit I2 and has a flange I361) on its outer edge which rests upon a seat 64c (Figure 4) formed on the lower edge of the inner wall 640 (Figure 3) of passageways 28 and 38 (Figure 5). The undersurface of shell I38 juxtaposed to the surface of member I5 is somewhat cycloidal. It will be noted that as the passageway between the shell I38 and the surface of member I6 is followed downwardly it gradually diminishes in width, thus forming nozzle 20. As the grain passes through nozzle 20, its maximum and raising speed is approximately 200 feet a second. It should be pointed out here, however, that the velocity of the air stream in this apparatus is governed by the rate of speed of blower I4, so that the miller can set the velocity of the air stream at the rate required by the characteristics of the product being milled, by means of a variable speed motor.

When the product being milled strikes the targets, it is shattered, the smaller particles being carried by the stream of air through the gaps between the targets into

passageways

28 and 30, and the larger particles falling downwardly within the target array into hopper 24. As the targets are of rectangular shape in cross section, and as the targets are radially positioned with respect to the axis of the target array as a whole, the gap between each pair of targets gradually increases in width from the inside to the outside of the target array. This prevents any of the slots from becoming clogged by particles of the product being milled.

All of the outer walls of passageways 28 and 36 (Figures l and their top walls, and the upper portions of their inner walls are an integral unit formed by housing 64. The outer walls 642) of both passageways, when considered as one unit, form a cylindrically-shaped member equidistantly spaced at all points from target array 22 (Figure 4). The upper inner walls 640 (Figures 3 and 4) also form a cylindrically-shaped member when considered as one unit, and together with target array 22 form the inner walls of

passageways

26 and 36. The depth of each passageway constantly increases as they are followed to the right (Figure 5) Thus, at any given point between vane 32 and port l38, the total cross-sectional area of either passageway is able to accommodate the entire flow into that passageway between the given point and vane 32 (Figures 4 and 5), which is secured to housing 64 by stud screws I39 (Figure 4) As a result, the air stream flows evenly through the target array, and each individual stream flows through an arc of 180, joining each other at port I36 (Figure 5).

As the two streams passing through

passageways

28 and 36 converge on port I38, to prevent swirling, they are directed by a pair of curved guiding plates I69 and I42 (Figures 4 and 5) into intake 34 of cyclone collector 36. Guiding plates are vertically positioned in

passageways

28 and 36 and are connected to housing 64 by studs MI. As the velocity of the air stream has been slowed down in

passageways

28 and 38, once in cyclone collector 36, the milled particles drop from the lower end of the cyclone collector 36 into hopper 36. Hopper 33 is emptied by air lock valve 42 (Figure 9), which prevents the air stream from passing downwardly into chute 46. This valve is driven at whatever rate it is necessary to empty hopper 38 into chute 46. Air from collector 36 (Figure 1) passes upwardly through conduit 44 into blower M, which is driven by motor I46, and thence recirculated through the apparatus.

In operation, the miller selects the particular type of target array necessary for the classification which he wishes to produce and the type of milling to be done. This is inserted in the apparatus and the rate of motor I46 is set at a speed which will produce the velocity desired at nozzle 26 (Figure l). When the motor is in operation, the product to be milled is permitted to flow through spout I6 (Figure 1). The air stream passing through conduit I2 projects the grain from nozzle Illa upon cycloidal member I6, which with shell I36 forms a nozzle directing the product being milled against target array 22. The larger particles fall downwardly into hopper 24, and thus pass into chute 26 (Figure 1). The smaller particles pass through the target array into passageways 28 and 30 (Figure 5) and thence -through port I38 into the intake 34 of cyclone collector 36, the air streams from

passageways

28 and 30 being guided in the port by guiding plates I46 and I42. In the cyclone collector 36, the milled particles pass downwardly and the air passes upwardly through conduit 34 to blower I4. If there is a shortage of air in the apparatus, this shortage willbe automatically taken care of by the air entering the apparatus through nozzle Illa with the stream of particles being milled. Any excess of air will flow down chute 26 (Figure 1) Whenever it is desired to clean the target array and interior of the apparatus or change the target array, targets, or conoidal member, screws I28 (Figures 1 and 3) are loosened and hopper 24, target array 22, and cycloid I6 will drop downwardly, guided by

legs

50, 52 and 54 and chute 26. The weight of these elements is counterbalanced, as pointed out hereinabove, by counterweights, such as counterweight I53 (Figure 1), positioned in the legs 53, E2 and 5d. Thus, it will be seen that the machine is designed for maximum efliciency in all respects, in that the interior of the machine is readily accessible for cleaning, that the target array can be changed as a unit if differently spaced targets are desired, and the individual targets if worn can be readily replaced by removing retaining ring 96. Because of the manner in which targets 22a are formed, they may be reversed when they become worn so that unworn outer surfaces and edges form the target surface. After the machine is cleaned or the target array changed, it is a simple matter to raise the hopper, target array and cycloid into operative position and replace the screws I28 and the machine is again ready for operation.

Referring to Figures 10, 11, 12 and 13, in which is illustrated a modification of the apparatus shown in Figures l-9, the machines are substantially similar in construction, with the exception of the passageway which connects the target array to the cyclone collector and the construction of the target array. In the apparatus shown in Figures 10, 11, 12 and 13, the hopper I48 positioned beneath the target array is detachably mounted on the machine, and when lowered is counterbalanced by counterweights positioned in its legs I50 in the same manner as hopper 24 in the embodiment shown in Figures 1-8 and the joint between hopper flange I461; and housing flange i520 being sealed by a gasket I5I. The housing l52 includes a wall I52a which follows a logarithmic spiral beginning at the inner edge of the mouth I5da of conduit I56 (Figure 10). Walls I62a, top I521; and the outer surface of target array I56 form a volute I63 which gradually increases in width as the target array I56 is followed in a clockwise direction. At the end of wall I52a nearest target array I56 a cutofi I33 is provided, the inner surface I58a of which forms a continuation of wall I52a and curves inwardly to a point where it practically touches target array I56. The outer surface I562; of cutoif I58 serves to direct the air stream and milled particles from passageway I60 into conduit I54 which increases in cross-sectional area throughout its length and thence into the intake I62 of a cyclone collector (not shown). Referring to Figure 12, to permit. passageway I66 to be con-.

7., nected to conduit I'54',,a,member3 I6I' isprovid'ed which extends transversely across, passageway I69. Member" I61 and cutofif I58 permitv conduit I54'to be connectedto passageway ISOJby means of its flange NM.

The target array in this embodiment consists of. a cylinder in which a series of slots 1-10 are milled extending longitudinally of the axis of the target array. The upper edge: of the target array is positioned beneath the top wall I521) of housing I52 and it is mounted in a seat I48b-formed onhopper I48. The shell I12; which covers the top of the space enclosed by-the target array,- is connected to the lower end of the conduit I64 and its flanged edge I;l2a rests upon the upper surface of top wall I521); Conoidal member- I68 is 'detachably mounted bya support I16 on the hub of a wheel-shaped member I78, the rim I 18a of which rests on a seat I480 formed on hopper I 8.

In operation, the air stream passing through conduit I54 (Figure acts upon the product to be milled as it flows out of spout I66 and carries it against target array I56, the air stream and the product being milled being directed by conoidal member I68 against target array III]. Because of volute I60, the air stream carries the product being milled evenly against target array I56 in all directions. The larger particles resulting from the impact of the product being milled against the target array pass downwardly into hopper I48, while the smaller particles are carried through the slots between the targets into volute I60 (Figure 10). The air stream flows around volute I60 in a clockwise direction (Figure 10), enters conduit I54 which slows down the velocity of the air stream to'fifty feet a second or less because of its constantly increasing size. The air stream then enters the intake I62 of a cyclone collector similar to collector 36 (Figure l). The remainder of the apparatus is similar to that shown in Figure 1. In this embodiment, the hopper, which is counterbalanced, may be lowered as in the previous embodiment for purposes of cleaning the interior ofthe machine or removing the'target array or-conoidal member.

Thus it will be seen that a practical and enicient method of milling has been disclosed, together with new and improved apparatus of one typesuitable for carrying outthe method of milling disclosed herein. Furthermore, it will be noted that the product being milled is classified by this apparatus in a new and improved manner and that the classification may be easily and quickly changed by changing the target array. Also, it will be noted that this machine is readily controllable by the miller so that the apparatus may be easily set to suit the characteristicsof the particular product being milled. It will now be clear that the several objects hereinabove' mentioned, as well as many others, have'been successfully accomplished.

As many possible embodiments may be made of the mechanical features of the above invention, and as the art herein described might be varied in various parts, all without departing from the scope of the invention, it is to be understood that all matter hereinabove set forth, or shown in the accompanyin drawings, is to be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. In apparatus of the type described, a vertically positioned conduit, means to create a stream of air flowing downwardly through said conduit, a stationary cone-shaped cycloid p0,- sitioned beneath said conduit, a cylindricallyshaped target array having its inner wall positioned outwardly from the lower edge of said cycloid, said target array including a plurality of vertically positioned, spaced targets, said stream of air carrying the product to be milled against said target array with sufiicient force to disintegrate the particles of which said product is comprised, means forming a passageway externally of said target array for collecting the particles or" said milled product passing through said target, array, and a hopper positioned beneath said target array for collecting the particles of said milled product which do not pass through said target array.

2. In apparatus of the type described, a conduit, means. to. create a stream of air flowing through said conduit,,means to introduce a prodnot to be milled into said stream of air in said conduit, a stationary conoidal member, the axis of said conoidal member being vertically positioned and aligned with the axis of said conduit, means coacting with said conoidal member to form a nozzle opening at the lower edge of said cone-shaped member, a cylindrically-shaped target array including, a plurality of vertically positioned spaced targets, said nozzle directing said stream of air and said product'to be milled against said target array, the product being milled being carried by said stream of air into said target array with suflicient. force to disintegrate the particles of which said product is comprised, passageway means positioned outwardly of said target array for collecting the particles of said milled product passing through said target array, and means positioned beneath said target array for collecting the particles of said milled product which do not pass through said target array.

3. In milling apparatus of the type described, a conduit, means to create a particle-carrying relatively high velocity stream of air through said conduit, means to introduce product particles to be milled into said high velocity stream of air to be airborne thereby, a cylindricallyshaped target array including a plurality of circumferentially spaced targets, realtively-fixed means for directing said stream of air and said airborne product particles to be milled radially out against said target array, and passageway means positioned exteriorally and. circumambiently of said target array leadingto discharge means, said passageway means being gradually increasing in cross section toward said discharge means from locality most remote from the latter so that said stream of air will flow evenly through said target array at substantially all circumferential points.

4; In, apparatus of the type described, a conduit, means to create a stream of air flowing through said conduit, means to introduce a product to be milled intosaid stream of air, a cylindrically-shaped target array including a plurality of spaced targets, means for directing said stream of air and product to be milled against the inside of said target array, means forming a passageway positioned outwardly from said target array, an exhaust port for said passageway, means positioned in said passageway opposite said exhaust port dividing said passageway into two sections, each of said sections increasing in cross sectional area throughout their lengths, the enlarged ends of said sections opening into said exhaust port, means for collecting the particles of the milled product passing out of said exhaust port, and means for collecting the particles of the milled product which do not pass through said target array.

5. In milling apparatus of the type described, in combination, a conduit, means for creating a particle-carrying relatively high velocity stream of air flowing through said conduit, a cylindrically-shaped target array, a relatively-fixed conoidal member for directing said particle-laden stream of air against said target array and supported coaxially in and with the latter, said target array including a plurality of circumferentially spaced targets, said stream of air carrying the product being milled against said target array with sufiicient force to disintegrate the particles of which said product is comprised, a housing forming a passageway positioned outwardly and circumambiently of said target array, said passageway collecting particles of said milled product passing through said target array, a hopper removably positioned beneath said target array, said target array being mounted on and supported by said hopper, and means detachably connecting said hopper to said housing to permit said hopper, said member and said target array to be detached together from said housing for purposes of cleaning or repair.

6. In apparatus of the type described, in combination, a vertically positioned conduit, a blower for creating a stream of air passing downwardly through said conduit, means for introducing a product to be milled into the air stream passing through said conduit, a cylindrically-shaped target array, a conoidal member for directing said stream of air and the product to be milled outwardly against the inside of said target array, said target array including a plurality of vertically positioned spaced targets, means forming a passageway externally of said target array for collecting the particles of said milled product passing through said target array, a hopper positioned beneath said target array, said target array and said conoidal member being mounted on said hopper, a framework, means detachably connecting said hopper to said framework, said hopper being movable downwardly away from said framework, and means for counterbalancing said hopper, target array and conoidal member when it is moved downwardly out of assembled relationship with respect to said framework, the interior of said passageway, said target array and said conoidal member being readily accessible for purposes of cleaning or repair when said hopper is detached from said framework.

7. In a target array for apparatus of the type described, in combination, a circularly-shaped supporting framework, a plurality of slots formed in the periphery of said framework, a ring member, a plurality of spaced slots formed in said ring member, means for supporting said ring member above the periphery of said supporting framework, said slots in said framework and ring member being aligned with respect to each other and being radially positioned with respect to the axis of the target array, a plurality of targets, each target being of rectangular shape in cross section, the upper and lower ends of each of said target's being positioned in aligned slots in said supporting framework and said ring member, and means for retaining the upper ends of said targets in the slots i g mem e an means for 10 retainingthe lower ends of said targets in the slots in said supporting framework, said targets forming a cylindrically-shaped target array and being detachably mounted on said supporting framework and ring member.

8. In milling apparatus of the type described, in combination, a blower, a conduit, said blower forcing a stream of air through said conduit, means for introducing particles of a product to be milled into said conduit, a cylindrically-shaped target array including a plurality of circumferentially-spaced targets, relatively-fixed means for directing said stream of air and the product being milled radially out in all directions against said target array, a hopper positioned beneath said target array for collectingthe particles of the product being milled which do not pass through said target array, a passageway in the shape of a volute positioned outwardly adjacent to and circumambiently of said target array to extend substantially 360 thereof and of gradually increasing capacity in a downstream direction toward its outlet to assure passage of substantially uniform quantities of air through said target array at substantially all radial points, and means to receive milled product-laden air from the passageway outlet and separate the milled product from the air stream.

9. In milling apparatus of the type described, in combination, a conduit, means to create a particle-carrying relatively high velocity stream of air in said conduit, means for introducing product particles to be milled into said stream of air, a cylindrically-shaped target array includ-- ing a plurality of circumferentially-spaced targets, relatively-fixed circumambient nozzle means to direct said stream of air and the airborne product particles to be milled radially out against the inside of said cylindrically-shaped target array, said stream of air constituting the sole motive force for and carrying said product particles against said target array with sufficient force to disintegrate the particles of which said product is comprised, means forming a passageway positioned externally and circumambiently of said target array with the outer side of the latter defining the inner side of said passageway, said passageway extending completely around said target array and being in the shape of a volute of gradually increasing capacity in the downstream direction toward its outlet end, means for collecting the airborne milled particles passing through the open outlet end of said volute, and means for collecting the larger milled particles falling downwardly from within said target array.

10. In an apparatus of the type disclosed, a vertically positioned conduit, a blower for creating a stream of air flowing downwardly through said conduit, means for introducing kernels of grain into said downwardly flowing air stream, a stationary cone-shaped cycloid positioned beneath said conduit, the axis of said cycloid being aligned with the axis or said conduit, a cylindricallyshaped target array, the axis of said target array being aligned with the axis of said cycloid, a housing member positioned above said cycloid, said housing forming an annular nozzle with said cycloid, said nozzle directing grain outwardly radially with respect to the axis of said cycloid against said target array, said stream of air carrying the kernels of grain against said target array with sufiicient force to disintegrate the kernels of grain, means forming a passageway externally of said target array for collecting the particles of said milled product passing through said target array, means for'separating the air stream carrying said product from said productya conduit for leading said 'air 'streamto said blower and a hopper positioned beneathsaid target array for collecting the particles of said kernels of grain which do not pass through-said target array.

11. In grain milling apparatus the combination comprising; feeding means to supply kernelcarrying, high velocity gaseous medium; a relatively fixed nozzle having an axial inlet opening connected to said feeding means and a circumferentially-arranged, circular, laterally-directed outlet orifice with the interior passage between said opening and orifice being bell-shaped and defined by substantially cycloidal converging walls; a drum-like, vertically-slotted target array arranged coaxially with'and circumambiently of said nozzle outlet orifice, each of the targets of said array comprising an elongated bar substantially rectangular in cross-section having one of its edge faces facing said orifice substantially normal to a radius of said nozzle; a vertically-movable hopper disposed beneath said array for collection of coarse particles which do not pass laterally through said array with the lattter mounted on and supported by said hopper to be lowered and raised therewith; and casing means surrounding said array and forming therewith delivery .passage means for fines-ladengaseous medium and terminating in an outlet for connection-to separatingapparatus, said delivery passage means being defined by gradually diverging walls for gradual increase of the capacity thereof as said outlet is approached to assure substantially even distribution of fines-laden gaseous medium through said arrayatsubstantially all circumf erential points.

12. The-gra'inmilling apparatus as defined in claim 11 characterized by said. array being in the form of .an open, substantially cylindrical frame- REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 90,097 Hanford May 18, 1869 139,782 Goodhart June 10, 1873 414,431 Morse Nov. 5, 1889 994,596 Marks June 6, 1911 1,108,542 Anderson Aug. 25, 1914 1,211,736 Marshal Jan. 9, 1917 1,241,749 McCool c Oct. 2, 1917 1,512,323 Wallace Oct. 21, 1924 1,608,717 Bell Nov. 30, 1926 2,417,078 Jones Mar. 11, 1947 FOREIGN PATENTS Number Country Date 152,603 Great Britain Feb. 15, 1922 556,058 France July 11, 1923 452,306 Germany Nov. 8, 1927