US1778193A - Mixing apparatus - Google Patents

Description

Oct. 14, 1930. B. G. KLUGH MIXING APPARATUS 4 .Sheet .--Sheet 1 Filed June 14, 1926 Oct. 14, 1930. B. G. KLUGH MIXING APPARATUS 4 Sheets-Sheet 2 Filed June 14, 1926 Oct. 14, 1930. B. G. KLUGH MIXING APPARATUS Filed Jun 14, 1926 4 Sheet-Sheet 5 qml fiesses waif Oct. 14, 1930. a. G. KLUGH MIXING APPARATUS Filed June 1926 4 Sheets-Sheet 4 01" ngy advantage, particularly where materials of Patented Oct. 14, 1930 UNITED STATES PATENT OFFICE BETHUNE G. KLUGH, OE CHICAGO, ILLINOIS, ASSIGNOR TO AMERICAN ORE RECLAMA- TION COMPANY, OF NEW. YORK, N. Y., A CORPORATION OF NEW YORK mxme arrana'ros' Application filed June 14} ized ores for sintering. While the machine has been developed primarily for this specific field, nevertheless it will be understood that the characteristic features and mode of operation of the machine can be employed in other types of mixing apparatus with equal the fineness and consistency of these sintering ores are to be handled.

In preparing ores. for sintering, it is necessary that the water added to the ore be accurately proportioned and intimately mixed with the ore, so that the resulting mixture will be substantially homogeneous in character. When handling ores of certain characteristics, particularly those of plastic nature and of extreme fineness, this mixing operation presents numerous dilficulties. This can best be illustrated by considering the types of machines which have been employed heretofore for performing this mixing operation. These prior machines may be generally classified as: (l) the cylindrical type, known as drum or tube mixers; and (2) the trough type in which rotates one or more blades, this being reI'erred to as the pug-mill type. In the case of extremely plastic ores, the cylidrical mixer does not perform satisfactorily, as the ore, when moistened to that degree required for sintering, tends to agglomerate into large masses or balls in this type of mixer, which action either prevents intimate mixing of the constituents of the sintering charge, or prevents thorough admixture of the water therewith. Furthermore, in this type of mixer, as heretofore constructed, the ore tends to adhere to the inner walls of the cylinder and to build up in successive strata on these walls.

These extremely plastic ores also introduce difiiculties in the operation of the pug-mil] type of mixing machine. Such ores tend to pack hard in the trough below the peripheral path of the blades, and this incrusted mass produces a braking retardation on the blades, necessitating a greater expenditure of power 1926. Serial No. 115,768.

and also resulting in rapid wearing of the blades.

With a view to overcoming the difficulties inherent in both these prior types of mixers, I have developed the present type of mixer, utilizing certain characteristics of each of these prior types, but avoiding the objections inherent therein. More particularly, I employ a blade action in combination with a r0- tating cylinder, the cylinder operating in the manner of a rotating trough for constantly feeding the material to the action of the blades, the cylinder and blades thus cooperating to the end of intimately mixing the material, without giving the material any opportunity to adhere and harden on the inner walls of the cylinder.

A further feature of my invention pertains to improved means for bal1ing'the mixture after the ore has been passed through the mixing apparatus and has been brought to the proper consistency for this balling away to illustrate the relation of the mix ing blades;

Fig. 2 is a transverse sectional view taken on the irregular sectional plane of the line 22 of Fig. 1;

Fig. 3 is a side view of the machine illustrating the cylinder in longitudinal section;

Fig. 4 is a detail view of one of the blade units;

Fig. 5 is a side elevational View, somewhat diagrammatic in character, illustrating my improved mixing apparatus having associated therewith a balling cone for balling the ore after the mixing thereof;

Fig. 6 is a similar view illustrating a balling cone which is contiguously joined to the mixing cylinder;

Fig. 7 is a side view of another embodiment embodiment and Fig. 9 is a transverse sectional view through one of the balling cones, illustrating a polygonal contour which may be given these cones.

The machine comprises a bed or base frame I 11 above which is supported the revolving cylinder 12. Four pairs of bearing blocks 13 rise from this bed, two pairs at each side thereof, and support the journal ends of four flanged rollers 14. Adjacent its ends, the cylinder 12 has secured thereto circular treads or rings 15 which whereby the cylinder is supported for rotary motion. The flanges of the rollers 14; engage on the inner sides of the tread rings 15, thereby holding the cylinder against endwise shifting movement.

Rising from the ends of the bed 11 are two bearing standards 16 and 17 in which are journaled the ends of two blade supporting shafts 18 and 19 which pass through the cylinder 12 adjacent the lower portion thereof. The right hand ends of these shafts (Fig. 1) are journaled in bearings 21 mounted on the bearing standard 16, and the left hand ends are journaled in spaced pairs of bearings 22 and 23 mounted on the opposite bearing standard 17. The two shafts are geared together for rotation in opposite directions by two spur gears 24 and 25, mounted on these shafts in meshing relation between the pairs of bearings 22 and 23. These gears are preferably enclosed in a suitable gear housing 26 supported between the pairs of bearings 22 and 23. One of the shafts, preferably the shaft 18, is extended beyond the endmost bearing 23 for mounting a driving element 27, such as a pulley or gear, through which driving energy is transmitted to the machine. Those portions of the two shafts 18 and 19 which extend through the cylinder 12 may be of square or polygonal section for mounting the blade units, as will be hereinafter described, and when thus constructed of polygonal section these shaft portions are preferably made separable from the shaft ends which are journaled in the bearings 21, 22 and 23. Cooperating pairs of collars 28 and 29 may be provided for joining the left hand ends of each of these polygonal shaft sections to the cylindrical shaft section, and clamping members 31 may be employed for joining the right hand ends of these polygonal shaft sections to the cylindrical shaft ends which are journaled in the bearings 21.

The right hand end of the shaft 18 is extended beyond the right hand bearing 21 for receiving a spur pinion 32 which meshes with a large spur gear 33. This large spur gear is mounted on a countershaft 34 extending alongside the cylinder 12 and journaled in roll on the flanged rollers 14;,

spaced bearings 35 and 36 mounted on frame extensions 37 and 38. Secured to the other end of this countershaft is a small sprocket wheel 39 over which tracks a. driving chain 41. This chain passes around a sprocket ring 12 which is secured to the outer circumference of the cylinder 12, preferably at a point intermediate the tread rings 15.

It will be apparent that as a result of this driving relation between the shafts and the cylinder, driving rotation imparted to the pulley 27 in the direction indicated will result in rotation of the two shafts l8 and 19 in opposite directions, and-in rotation of the cylinder 12 in a. counterclockwise direction as viewed in Fig. 2. V

Mounted on the shafts 18 and 19 at spaced points along their, lengths within the cylinder 12 are a plurality of paddles or mixing blade units 44. As best shown in Figs. 2 and 1, these blade units each consists of a hub 15 fixedly mounted on the shaft. and oppositely extending blade arms 46. WVhere the blade mounting portions of the shafts 18 and 19 are of square or polygonal section, the hubs 15 are of corresponding form so as to be rigidly mounted on these shafts. As viewed from the end, (see Fig. 2), the two blade arms project at an angle or non-radially relative to the square hub 45 in a trailing direction or rearward with respect to the direction of rotation of the shaft. In addition to having this rearward non-radial angle, each blade is disposed helically relative to its hub so that it will have a feeding pitch for gradually feeding the material back through the cylinder along the bottom thereof. As shown in Fig. 1, the blade units on one shaft are offset or staggered relative to the blade units on the other shaft, so that the blade arms will clear each other. These blade arms inscribe arcs of rotation which intersect or overlap each other as viewed from the end, see F ig. 2. The blade units on the two oppositely rotating shafts have their blade arms oppositely ar ranged with respect to the trailing angle of inclination and the helical pitch angle above described. Preferably, the two shafts 18 and 19 are spaced equidistantly from a vertical axial plane passing through the axis of the cylinder, and the shafts are supported at the proper vertical height to space the blade ends from the inner wall of the cylinder, substantially as shown in Fig. 2. The blades may be provided with holes 17 therein for receiving the bolts of supplementary blades which can be bolted to the old blades when the edges of the latter have worn down.

To remove any material tending to adhere to the side walls of the cylinder 12 there is provided a scraper 48 extending longitudinally of the cylinder from end to end thereof. This scraper is preferably positioned to engage the inner wall of the cylinder at a point approximately above the shaft 18. The scraper is mounted on a shaft 49, the ends of which project beyond the ends of the cylinder 12 for mounting in bearings 51 carried by a stationary frame structure 52 embracing the ends of the cylinder. Arms 53 extending from the ends of this scraper shaft 49 support counterweights 5st which tend to hold the scraper pressed against the side wall of the cylinder. The scraper preferably extends forwardly against the direction of rotation of the cylinder so that the action of shearing the material from the wall of the cylinderwill operate to press the scraper with greater pressure against this side wall.

The water for admixing with the ore is sprayed downwardly from an apertured spray pipe 56 extending longitudinally of the cylinder adjacent the upper part thereof. The volume of water projected through these downwardly opening spray apertures can be regulated by the control valve 57.

The ore is fed to the mixer through an inlet chute 58 which discharges into the right hand end of the cylinder. The hopper is supported in any suitable manner, as by the framework 52 which supports the scraper a8, and at its lower end carries a circular end plate 59. The scraper shaft a9 extends out through this stationary end plate 59 at this end of the cylinder. An inwardly extending closure ring 81 is secured to this end of the cylinder, being set outwardly from the end plate 59 to overlap this plate, substantially as shown in Fig. 3, the two forming an end head for this end of the cylinder.

The opposite end of the cylinder overhan 's a discharge hopper 62 which has a laterally flaring upper portion 63 embracing the sides of the cylinder at this discharge end, and a constricted lower portion 64 which passes down through an opening in the base frame 11. The outlet from the hopper may discharge to any suitable point, where the ore may be further treated, or conducted directly to the sintering apparatus. In the operation of the device the ore is admitted at a predetermined rate through the feeding hopper 58, creating a bed of the material in the bottom of the cylinder in the zone of the blades. These blades, by their opposite rotation in the directions indicated will tend to confine this material in a pile in the lower part of the cylinder. ldoreover,'the two sets of blades, by rotating in the directions indicated, have the action of throwing the material upwardly between the two shafts in a veritable shower of material, which falls baclr upon the blades and upon the sides of the cylinder. The consequent agitation or stirring of the material will present new surfaces to the action of the water projected down from the overhead spray pipe 56. As the material becomes somewhat plastic or ad hesive it will tend to adhere to the side walls of the cylinder, being carried up to the scrapspreading of the material laterally in the op A posite direction is defeated by the motion of the cylinder which immediately carries the material back into the zone of blade action. No tumbling of the material within the cylinder is desired, and this tumbling is avoided by rotating the cylinder at a relatively low speed. For example, 1 find a rotation of approximately one hundred and twenty-five revolutions per minute as being sutliciently low to avoid this tumbling action and still secure the necessary rate of return feed to the blades for greatest efficiency. The cylinder thus serves primarily as a moving trough surface, preventing packing on the side walls thereof, and continuously rolling the material back into the zone of blade action.

The action of the several blades on both shafts 18 and 19 is to feed the material progressively along the bottom of the cylinder simultaneously with their mixing action. The completely moistened and mixed material is finally discharged over the outlet end of the cylinder into the discharge hopper 62.

t may be desirable to employ only one shaft and its associated mixing blades, and in such instance this one shaft is disposed slightly to the right of the vertical axial plane of the cylinder, in the direction that the shaft 18 is removed from this vertical axial plane in Fig. 2.

In Figs. 5 to 8, inclusive, I have shown supplementary apparatus for balling the mixture after it has been mixed and moistened in the cylinder 12. Such balling of the sintering mixture into small spherical aggregates tends to increase its speed of sintering in down draft sintering apparatus. However, before such balling operation is performed it is necessary or desirable that the materials be intimately mixed and moistened. For example. if an ore of plastic nature were being mixed with finely divided carbonaceous fuel, there would be a tendency for the ore to agglomerate into large masses under the tumbling action of the mixing or balling cylinder, which would prevent the thorough admixture of the carbonaceous fuel therewith. However, by first mixing the materials in the manner hereinbefore described, the required intimacy of mixture of the fuel and ore is first obtained, whereupon the re sultant mixture, properly moistened, can be subjected to the desired balling action. By performing the steps in this manner the small globular aggregates are made of uniform Elli till

composition, which is desirable for the sintering operation.

Figs. 5 to 8. inclusive, are somewhat diagrammatic inasmuch as the mixing cylinder 12 is not illustrated at its full length, al though in some instances it may be practicable to use a comparatively short mixing cylinder. Referring particularly to Fig. 5, the mixing cylinder discharges into a rotating drum or chamber 66, preferably of conical form. The blade units on the shafts 18 and 19 are not extended into this balling drum, and hence the material precipitated into the drum is not subjected to any further mixing thereby. In the embodiment disclosed in Fig. 5, the balling drum is provided with tread rings 67 and 68 adjacent its ends, which tread rings track on rollers 69 and 71, similarly to the mounting of the mixing cylinder 12. The discharging end of the mixing cylinder 12 extends a short distance into the smaller end of the balling drum 66. The large end of this balling drum can be arranged to discharge into a chute or receptacle, as desired. The balling drum is driven by a chain 72 passing over a sprocket wheel 7 3 on the countershaft 3'4 and tracking over a sprocket ring 7% secured to the circumference of the balling drum. The balling drum may be. driven at a higher speed than the mixing cylinder 12 to augment the tumbling and balling action of the material.

Fig. 6 illustrates the same general relation of balling drum and mixing cylinder. with the exception that in this embodiment the balling drum is secured directly to the end of the mixing cylinder so as to rotate therewith. The outer end of the balling drum is preferably provided with a tread ring 68 rolling on rollers 71 to support this end of the drum.

In Fig. 7 the conical balling drum is extended backwardly over the mixing cylinder 12. this affording a relatively short, compact construction. In this form the inner end of the mixing cylinder is provided with extending arms which are fastened to a tread ring 76 tracking on the rollers 77. The balling cone 66 is provided with tread rings 67 and 68' tracking on pairs of rollers 69 and 71'. In this construction, the balling cone 66 is adapted for rotation independently of the mixing cylinder 12, and consequently, if desired, this balling cone can be rotated at a higher speed through its sprocket chain 72. The discharge end of the balling cone may discharge into any chute or receptacle below the mixing cylinder. In this instance the driving chain 41 tracks over a sprocket ring 42 at the feed end of the cylinder.

In Fig. 8 the same general relation of mixing cylinder and balling cone is employed except that these two elements are connected together for simultaneous rotation. Small angle brackets 81 may be secured between the diseh arge end of the mixing cylinder and the small end of the balling cone. Likewise, larger brackets 82 may be secured between the inlet end of the mixing cylinder and the discharge end of the balling cone. In this embodiment the drive is directly to the sprocket ring 74' encircling the outer circumference of the balling cone.

The action of the balling cone in each of the preceding embodiments is to carry a portion of the moistened material up along its side wall and to thereupon drop this material, allowing it to roll downwardly and agglomerate into spherical form. by adherence between the moistened particles. Simultaneously with this downward rolling motion of the material along the side walls of the cone,-the material is also rolled longitudinally of the cone towards its larger end, which latter rolling motion also assists in agglomerating the material into spherical form. The pitch of the cones is such that the action is automatic in that when the material has united in spheres of sufficient size these spheres or balls will roll down the. slope of the cone and discharge at the large end thereof; while the material which has not been balled will have a much slower rate of feed down the slope of the cone.

In Fig. 9 I have illustrated a polygonal formation which I may give either of the balling cones described in the preceding embodiments. This polygonal contour is advantageous in that it secures a more pronounced balling action. This follows from .the fact that the mixture resting on each surface of the polygon will rise to a certain angle, at which point the material will roll back over its surface. The finer, unballed portion will tend to cling to the polygonal surface at higher angles, with the result that the small aggregates rolling over such fine portion will result in the fine portion tending to adhere thereto, thereby increasing the size and degree of sphericity of such aggregates. This polygonal formation of balling cone, in particular, can be rotated at higher speed than the mixing cylinder, for securing effective balling of the mixture.

What I claim as my invention and desire to secure by Letters Patent, is

1. In m'xing apparatus, the combination of a troug member, a pair of shafts having mixing blades thereon operating within said trough member, said shafts being rotated in opposite directions, and means for moving said trough member for confining the material within the radius of action of said blades.

2. In mixing apparatus, the combination of a horizontally disposed rotating cylinder, a pair of shafts disposed in said cylinder having mixing surfaces thereon operating adjacent the bottom of said cylinder, said shafts lid being rotated in such directions as to cause the material being mixed to be thrown upwardly between said shafts, said cylinder being rotated for confining the material within the radius of action of said mixing surfaces.

3. In mixing apparatus, the combination ofoa horizontally disposed cylinder. the lower portion of which defines a trough bottom, a pair of shafts disposed on opposite sides of the vertical axia plane of the cylinder and having mixing blades thereon operating within said trough bottom, the blades on one shaft being staggered relative to the blades on the other shaft, and means for rotating said shafts and said cylinder.

4.. in mixing apparatus, the combination of a horizontally disposed cylinder, the lower portion of which defines a trough bottom, a pair of shafts having mixing blades thereon operating within said trough bottom, the blades on one shaft being staggered relative to the blades on the other shaft, and means for rotating said cylinder and for rotating said shafts in opposite directions, so as to cause the material being mixed to be thrown upwardly between said shafts.

5. ln mixing apparatus, the combination of a horizontally disposed rotating cylinder, the lower portion of which defines a trough bottom. a pair of shafts having mixing blades thereon operating within said trough bottom, the blade units on one shaft having their blade arms oppositely arranged with respect to the trailing angle of inclination of those on the other shaft, means for rotating said cylinder and said shafts, said shafts being rotated oppositely and in such directions as to cause the material to be thrown upwardly between said shafts, and a scraper operating to remove material adhering to the inner wall of said cylinder.

6. In mixing apparatus, the combination of a horizontally disposed cylinder, the lower portion of which defines a trough bottom, a pair of shafts having mixing surfaces thereon operating within said trough bottom, means for rotating said shafts and said cylinder, a scraper for removing material tending to adhere to the inner wall of said cylinder, and means for yieldably holding said scraper in operative position.

7. In mixing apparatus of the class described, the combination of a cylinder disposed substantially horizontally, a plurality of supporting rollers, tread rings on the outer side of said cylinder tracking on said rollers, a pair of shafts extending longitudinally within said cylinder and disposed on opposite sides of the vertical axial plane of said cylinder, mixing blades on said shafts, the lower portion of said cylinder defining a trough bottom for said mixing blades, means for rotating said shafts in opposite directions to cause the blades to revolve downwardly from the outer sides of said shafts towards said trough bottom, and a toothed member on said cylinder through which driving rotation is transmitted to said cylinder.

8. In mixing apparatus of the class described, the combination of a drum of generally cylindrical 'forrn disposed substantially horizontally, tread rings on said drum, supporting rollers on which said tread rings track, a pair of shafts extending longitudinally through said drum and disposed on op- V posite sides of the vertical axial plane of said drum, mixing blades on said shafts operating adjacent the lower side of said drum, means for rotating said shafts oppositely and in such directions as to cause said blades to revolve downwardly from the outer sides of said shafts toward said axial plane, a countershaft operatively connected to one of said first shafts, a sprocket ring mounted on said drum, a sprocket on said countershaft, and a driving chain tracking over said sprocket and sprocket ring.

9. ln apparatus for preparing powdered or pulverized ores for sintering, the combination of a base, a horizontally disposed cylinder, supporting rollers mounted on said base, tread rings on said cylinder tracking on said rollers, means for feeding the ore into one end of said cylinder, a pair of shafts extending through said cylinder, said shafts being disposed substantially in the same horizontal plane and being spaced substantially equidistantly from the vertical axial plane of said cylinder, mixing blades mounted on both of said shafts and rotating through overlapping arcs in proximity to the bottom of said cylinder, a water spray pipe extending longitudinally within said cylinder for spraying water on the material therein, and means for revolving said shafts and cylinder, said shafts being revolved oppositely and in such directions as to cause the blades to throw the material upwardly between said shafts.

10. In. apparatus for preparing ores for sintering, the combination of a rotating cylinder disposed substantially horizontally, a pair of shafts extending through said cylinder, each of said shafts comprising a shaft portion of polygonal cross-section disposed within the cylinder and a shaft portion of round cross-section extending co-extensively therefrom from the end of said cylinder, mixing blades mounted on the two polygonal shaft portions, bearings in which the rounded shaft portions are journaled, collars on said co-extensive shaft portions for joining the same together, and means for rotating said cylinder and said shafts.

11. in apparatus for preparing ores for sintering, the combination of'a rotating cylinder disposed substantially horizontally, a rotating shaft of polygonal cross-section extending through said cylinder, and mixing members mounted on said shaft for mixing the ore within said cylinder, each of said mixing members comprising a hub having a polygonal opening therein for engaging nonrotatably on said shaft, and comprising blades formed integral with said hub and extendin from diametrically opposite sides thereo each of said blades having a helical feeding pitch and projecting non-radially from said hub in a trailing direction with respect to the direction of rotation of said shaft.

12. In mixing apparatus, the combination 7 of a cylinder disposed substantially horizontally, rollers engaging tread surfaces on the outer side of said cylinder for rotatably supporting the latter, a pair of shafts extending longitudinally within said cylinder and disposed on opposite sides of the vertical axial plane thereof, and mixing blades on said shafts, the arms of the blades inscribing arcs of rotation which intersect or overlap each other, and which lie in close proximity to the bottom of the rotating trough defined in said cylinder, for acting directly on the material carried downwardly along the side of said cylinder, said shafts being rotated oppositely and in such direction as to throw the material upwardly between the same. v

BETHUNE G. KLUGH.

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