US2656988A - Centrifugal milling and insect destroying machine with rotary impeller and annular target - Google Patents

Description

Oct. 27, 1953 F. 5. SMITH 2,656,988

CENTRIFUGAL. MILLING AND INSECT DESTROYING MACHINE WITH ROTARY IMPELLER AND ANNULAR TARGET FiiedNov. 9, 1948 3 Sheets-Sheet 2 FIG Oct. 27, 1953 5, SMITH 2,656,988

CENTRIFUGAL MILLING AND INSECT DESTROYING MACHINE WITH ROTARY IMPELLER AND ANNULAR TARGET Filed NOV. 9, 1948 5 Sheets-Sheet 3 INVENTOR FRA/VAL IN S. SM/m BY 6%; 61 4 AT x 1 40 244. TORNY5 Patented Oct. 27, 1953 CENTRIFUGAL MILLING AND INSECT DE- STROYING MACHINE WITH ROTARY IM- PELLER AND ANNULAR TARGET Franklin S. Smith, Hamden, Conn. Application November 9, 1948, Serial No. 59,151

3 Claims.

This invention relates to disintegration and separation, and more particularly to the milling of cereals such as wheat and to the destruction of insect life in such cereals. The present invention is related to and in some respects is an improvement upon the inventions disclosed in my Patents Nos. 2,501,622 and 2,582,509.

An object of this invention is to provide an improved apparatus for disintegrating bulk products such as cereals. A further object is to provide such disintegration with an accompanying separation whereby the particles of the disintegrated product are separated from each other in accordance with size. A further object is to provide for the above in such a manner that all insect life in the product is destroyed. A still further object is to provide for the treating of cereals such as wheat so as to obtain a uniform milling action which is followed immediately by a separation of the smaller particles of endosperm from the larger particles of the grain. A further object is to provide apparatus for carrying out the above which is efiicient and dependable in operation, simple and sturdy in construction, and relatively inexpensive to build, operate and maintain. These and other objects will be in part obvious and in part pointed out below.

The invention accordingly consists in the features of construction, combinations of elements, arrangements of parts and relation 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 drawings which show two illustrative embodiments of the invention:

Figure 1 is a vertical section of one embodiment of the invention with certain parts being shown in full lines;

Figure 2 is a top plan view of the apparatus of Figure 1 with parts broken away to show the internal structure;

Figure 3 is an enlarged fragmentary view of a portion of Figure 2; and

Figure 4 is a view similar to Figure 3, but showing another embodiment of the invention.

In my Patent No. 2,501,622 there is disclosed a method and apparatus for treating products particularly for milling wheat by passing a stream through an impacting and separating rotor. The rotor carries a large number of impactors which impact the grain with suflicient force to cause a disintegration; and, the stream then passes along a rotating separation surface formed by a perforated wall where a separating action takes place. Accordingly, the arrangement is such that the smaller particles of the product pass through the perforations and are directed downwardly in a separate stream, whereas, the larger particles pass along the perforated surface and into another stream for further millmg.

In my Patent 2,582,509 a stream of the product is also subjected to an impacting action, but the impacting results from impelling the product by a rotor and projecting it against an array of stationary targets. The targets are constructed similar to the impactors of the apparatus of Patent No. 2,501,622 although as indicated, they are mounted on the stationary frame rather than on the rotor. The present invention is similar to that of Patent No. 2,582,509 in that an array of stationary targets is positioned around a rotor which projects the product against them. Furthermore, the present invention contemplates the separating of the treated product in accordance with size and thus is relative to the invention of Patent No. 2,501,622. However, the target arrangement is of an improved construction and there are certain other new features so that improved results are obtained.

Referring particularly to Figure l of the drawings, a housing 2 has at the top a shell construction 4 including a main frame 5 to the bottom of which is screwed a hopper structure 6. Housing 2 is supported by three legs 8 each of which is received with a push fit at its upper end in a socket 9 formed in a bracket II] on frame 5, and the lower end of each leg is provided with a floor flange or foot H. Mounted on the top of frame 5 by means of a spider structure, formed by three legs I2 and a flanged rin [3, is a variable speed electric motor 14. Each leg l2 has a downwardly extending bracket [5 and screwed to these brackets is the central disc-like top wall I 9 of the shell construction 4. Motor [4 has a downwardly projecting shaft which extends through an elongated bearing structure [6 which includes a heavy duty roller type hearing I! indicated in broken lines, and the shaft terminates in a tapered extension [8. The top wall I 9 of the shell construction has a central product inlet opening 20 through which the motor shaft extends, and this opening is surrounded by a downwardly extending collar 22.

Clamped to top wall H! at opening 20 is a chute 24 which has an annular flange 26 resting upon and screwed to the top wall l9 around the opening. The chute has in its top wall an opening 28 through which the bearing structure 16 projects with a snug fit. As shown best in Figure 2, the bottom wall 21 of the chute terminates on one side of the longitudinal center line of the chute in a lip 29 at collar 22, and on the other side of this center line the chute bottom wall extends downwardly into the collar (see also Figure 1) in the form of a segment 3|. At the bottom segment 3| terminates in a lip 30 which forms one radial edge of the segment, and its other radial edge 33 is along the longitudinal center line of the chute. Segment 3| is cut away to fit the outer wall of bearing structure l6 and the inner surface of collar 22, along the plane of the upper surface of the bottom wall of the chute.

Fixed to the tapered extension l8 of the motor shaft, by a nut 32, a washer 34 and by a conventional key and key ways (not shown), is a rotor 36 which is concentrically positioned directly beneath the product inlet opening 20. Rotor 36 is formed by a lower dish-shaped base member 38 and a top member 40 rigidly connected together. Member 38 has a central hub portion 39 which is surrounded by an upwardly and outwardly extending wall which terminates in an annular flange ll which presents an upper fiat annular surface 42. Member 40 is generally annular, but has adjacent its outer edge a number of equally spaced flat radial vanes 44, which are illustratively seventy-two in number and which project downwardly and have bottom surfaces which abut surface 42 of member 38. These vane are of the cross-sectional configuration shown best in Figure 3 with each having a leading surface 36, a trailing surface 48 and end surfaces 50 and Thus, between each two adjacent vanes there is a passageway 49 and the stream of the product is equally distributed amongst these passageways as it is impelled to the periphery of the rotor where it is discharged generally tangentially in an annular stream in the trajectory zone 53.

As indicated in broken lines in Figure 3, alternate vanes 44 are attached to member 38 by cap screws 52 (see also Figure 1) which secure members 38 and 40 together so a to form the rigid rotor structure. Equally spaced around the rotor are four Woodruff keys 53 which ensure that the two members are in accurate alignment and transmit the torsional load. The rotor 36 is shaped as shown with variable thickness for substantially uniform stress distribution; and so that its center of gravity coincides with the center of the lower bearing ll of the motor Hi; as indicated above, bearing ll is preferably of the heavy duty roller type and is located near the lower end of the elongated bearing structure l6. Rotor 33 and the rotor of motor M are dynamically balanced before installation; but due to probable load unbalance it is desirable to position rotor 36 as described to prevent bending of the motor shaft and excessive vibration.

Surrounding the periphery of rotor 36 is a circular row or array of elongated rectangular targets 56, in this embodiment one hundred and eighty in number, which project downwardly across the outlet from the rotor. These targets are rigidly mounted at their upper ends on a notched ring 51. Ring 51 is clamped to the outer edge of top wall I3 by a plurality of studs 68 and nuts 63a which extend through suitable holes on a mounting flange of the ring and the ring is formed of two semi-circular portions or halfsections, each of which carries ninety of the target 53. Frame 5 is separated from the outer edge of top wall 19 by an annular gap or opening 59 through which the targets project, and this annular opening is covered over by an annular inverted channel cover 6| which is clamped in place by a plurality of studs 63 and nuts 63a. Thus, by removing nuts 630/. the cover 6| may be lifted and held by rope or other convenient means (not shown) while access may be had to the target assembly and the associated parts. As ring 51 i formed in two semi-circular portions they may be removed readily between any two of the legs 12.

Referring now to the left-hand portion of Figure 3, each of the notches in ring 5'! has a broad face 62 and a narrow face 64, and the targets are firmly seated in the notches with the top of one side face 61 of each target against its notch surface 62, and with the top of one of its edge surfaces 65 against the face 34. Referring to the right-hand portion of Figure 3, these edge surfaces 66 form the target faces or impacting surfaces of the targets, and as the rotor 36 rotates counterclockwise, the product particles are projected against these target faces along Paths normal thereto.

The width of each target is greater than the width of surface 82 so that the edge of the target opposite the target face 6t overlaps the edge of the next adjacent target. Furthermore, the thickness of the targets is slightly less than the width of surfaces 64 so that there is a narrow slot or gap 63 at the outer edge of each target face. Thus, as shown best at the right-hand portion of Figure 3 the array of targets provides a large number of equally spaced target faces each substantially normal to the path of the product particles which are projected toward it from the rotor, and at the outer edge of each target face there is a narrow gap through which the air which accompanies the product and the smaller product particles may pass.

As shown best in Figures 1 and 2, surrounding the array of targets is an annular dispersion zone 69 into which the air and small particles pass from gaps 68. Within this zone the air velocity is reduced and the air is directed generally downwardly by the inner surface of frame 5. Targets 56 (Figure 3) are rectangular in cross-section and each is positioned at an angle of two de rees with respect to the next, and therefore, each-of the gaps 68 increases slightly in width away from its adjacent target face 66. Thus, any particle which enters a gap will pass through it and into zone 69. In this embodiment the gaps have a width of one sixteenth of an inch at their inlet edges so that particles of sizes greater than this are deflected downwardly along faces 56 and 61.

Referring again to Figure l, the hopper structure 3 of housing 2 is formed by two substantially concentric hoppers with there being an outer hopper T0 screwed to the bottom edge of frame 5, and an inner hopper 72 supported at its top by a ring 14 and a plurality of spaced brackets 16, each riveted at one end to hopper l0 and at the other end to ring 14. At the bottom, hopper 10 has an outlet chute connection 18, and hopper 12 has a similar chute connection 80. The upper edge of hopper l2 surrounds the bottom of the array of targets so that the air and product particles which pass through the gaps 68 between the targets into the dispersion zone 69 pass downwardly into hopper 10; whereas the larger particles which do not pass through these gaps fall downwardly inside the array of targets into hopper 12. Thus, the product is impacted to produce disintegration and substantially simultaneously the smaller particles are carried into the disperimpacting action wherein each particle of the product receives a predetermined impact.

Referring again to Figure 1 of the drawings, a stream of the product passes by gravity down chute 24 and substantially one-half of the product is directed by lip 36 in the direction of rotor rotation to the central portion of rotor 36, while the remainder of the product falls over lip 29 directly upon the central portion of the rotor. The lower edge of collar 22 tends to even the product flow to the contiguous dish-shaped portion of the rotor. The rotar movement of the rotor causes the product to spread out and flow in an even annular stream at an increasing velocity upwardly along the dish-shaped upper surface of the rotor. As the stream reaches the inner edge of surface 42 segments of the stream are picked up by vanes 44 on their leading surfaces 66 so that the stream is divided into a large number of small streams. Each of these streams spreads out upwardly along its surface 46, while the speed of flow is increased and this causes a further thinning out of the stream.

The product and accompanying air are discharged from the outlet of rotor 36 through the trajectory zone 53 to the array of targets 56. The trajectories of the product particles, such as the grains of wheat, are somewhat turbulent but flow in a generally tangential direction and at a velocity to cause disintegration or shattering upon impact with said array of targets. The product particles which do not directly impinge upon one target face are guided by the side surface 61 of the adjacent target member 56 to the target face of the next adjacent target in the trajectory direction. By reason of air flow through apertures or gaps into the relatively large diffusion zone 69 beyond the target array, eddy air currents within the trajectory zone are greatly diminished. Furthermore, as mentioned above the small product particles pass through gaps 68 with the air, and thelarge particles fall downwardly. Therefore, cushioning and deflection of the product particles near and at the target faces are substantially eliminated with resultant shattering of all the product particles.

As indicated above, the small particles of the shattered product are carried into the diffusion zone 69 and from there pass by gravity and air currents through the discharge opening 18 at the botton of the hopper; and the balance of the shattered product is carried by gravity and air currents directly from the target faces downwardly through the hopper discharge opening 86.

The illustrative embodiment of the invention is particularly adapted for the break system in the milling of wheat. When so used in one particular instance, the rotor was twenty-eight inches in diameter and was rotated at 1740 R. P. M. The target array was spaced from the periphery of the vanes substantially threefourths of an inch and the other dimensions are shown on the drawing substantially to scale. This machine has general application for disintegrating various products and it should be understood that the number of vanes on the rotor and the number of stationary targets, as well as 6 other characteristics of the machine, may be varied to suit particular uses and conditions of operation. Furthermore, the vanes may be curved, or inclined forwardly or rearwardly. The dimensions of the target faces and intervening apertures should be chosen to effectively treat a given product. In general, the height of the targets should exceed the height of rotor outlet, the width of the gaps or apertures 68 should be less than the average minor dimension of the product, and the face of the target may be wider or narrower than the average major dimension of the product, all depending upon the sort of break or shattering desired. In the present embodiment the impacting is of sufficient magnitude to destroy any insect life which may be present.

The prior milling machines in which the grain is impacted by revolving impactors do not shatter all of the kernals; but Cause bruising, fracture or chipping of the bran coat, with resultant fine bran fragments. The machine of Patent No. 2,501,622 produces fine bran fragments to a lesser extent than others of that general type. The impact miller of the present invention is a more efficient machine as it produces or causes a single impact with suflicient force to yield the required reduction, with fewer fine bran fragments and with less waste of energy.

During the milling operations, the different mill stocks vary in their requirements for satisfactory reduction. For example, in the break system this would mean, that the reduction would be set to obtain a maximum of coarse middlings, and a minimum of break flour without excessive breaking of the bran. This requirement for varying the reduction is met with the present invention by providing a choice of simple and inexpensive impacting members and of trajectory velocities. This latter by means of a variable speed motor.

The embodiment of Figure 4 is identical with that of Figures 1, 2 and 3 except for the dimensions of the targets, which are narrower and thicker, and the gaps therebetween. Accordingly, targets 56 of Figures 1, 2 and 3 are replaced in Figure 4 by targets 86 which are clamped to ring 51 by studs 58 and nuts 58a in the same manner in which targets 56 are held in place. Each target 86 has a target face 88 which is wider than the notch faces 64, and therefore, targets 86 overlap one another in the direction of their thicknesses; and, the width of targets 86 is less than the width of face 62 so that a gap 90 is provided between each two adjacent targets. Gaps 96 are of substantially the Width of gaps 68 so that during operation the smaller product particles and the air passes outwardly through these gaps.

The passage of the product particles through the rotor in the embodiment of Figure 4 is the same as that of th embodiment of Figures 1 to 3. However, as the product particles impact against the target faces 88 the air tends to flow through each of gaps 90 in the plane of the adjacent target face. In either of the illustrative embodiments of the invention the size of the gaps may be varied as desired by changing from one size or type of targets to another, and in this way a wide range of impacting and separating effects may be obtained with minimum change in the equipment.

As many possible embodiments may be made of the mechanical features of th abov 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 underget and the next adjacent target through which air and small product particles may pass, said ring structure having a notched periphery forming a plurality of seats each of which has one of said targets clamped thereto.

2. In apparatus of the class described, the combination of, a casing construction including a top shell and a bottom hopper structure, said top shell comprising a substantially cylindrical frame, a top wall concentrically positioned with respect to said frame at the upper edge thereof and of lesser diameter than said frame whereby an annular opening is provided between the periphery of said top wall and said frame, and a cover for said annular opening, said top wall having a product inlet opening, a rotor mounted in said shell and adapted to receive a stream of the product from said inlet opening and to direct the product outwardly toward the inner surface of said frame, and a target assembly comprising a ring structure mounted on said top wall adjacent said annular opening and a plurality of elongated targets mounted on said ring structure and projecting downwardly through said annular opening thereby to form an annular array of targets around said rotor.

3. In apparatus of the character described, in combination, a casing including a top shell structure having a central product inlet opening and a hopper structure at the bottom through which the product is discharged, a rotor mounted within said casing, means for driving said rotor, said rotor having a plurality of radial vanes which are adapted to direct the product so that it discharges the product substantially tangentially from the periphery of the rotor, said hopper structure including a pair of substantially concentric hoppers having separate discharge openings, and a cylindrically-arranged array of targets, each of said targets extending transversely across the path of the product being discharged from said rotor, the lower ends of each target in said target array extending downwardly into the inner hopper of said pair of hoppers, each of said targets including a target face lying in a plane substantially normal to the path of the product leaving said rotor, each target being spaced a slight distance from the next adjacent targets to provide spaces through which small particles may pass into the outer hopper, the particles which do not pass through said spaces passing downwardly into said inner hopper.

FRANKLIN S. SMITH.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 291,191 Ittner Jan. 1, 1884 1,108,542 Anderson Aug. 25, 1914 1,598,702 Bell et al Sept. '7, 1926 1,854,659 Lehmann Apr. 19, 1932 2,339,735 Smith Jan. 18, 1944 2,339,737 Hulse Jan. 18, 1944 ,344,611 Harris Mar. 21, 1944 2,421,014 Coss May 27, 1947 2,464,212 Carter et a1 Mar. 15, 1949 2,582,509 Smith Jan. 15, 1952 FOREIGN PATENTS Number Country Date 263,660 Great Britain Jan. 6, 1927 309,854 Great Britain June 25, 1928 850,356 France Sept. 1 1939

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