US2538556A - Furnace loading mechanism - Google Patents

Description

J n- 16, 95 E. 5. DE comous ET AL 2,533,556

FURNACE LOADING MECHANISM 2 Sheets-Sheet 1 Filed Nov. 5, 1947 Jan. 16, 1951 E, (5, E co oL s ETAL 2,538,556

FURNACE LOADING MECHANISM 2 Sheets-Sheet 2 4 Filed Nov. 5, 1947 Patented Jan. 16, 1951 FURNACE LOADING MECHANISM Ernest G. de Coriolis and Rollie P. Campbell, To-

ledo, Ohio, assignors, by mesne assignments, to Eric Mining Company, Hibbing, Minn., a corporation of Minnesota Application November 5, 1947, Serial No. 784,220

13 Claims. I

This invention relates to improvements in furnace loading mechanisms, and is particularly concerned with the provision of apparatus for delivering to and evenly distributing over the stockline of a charge in a vertical furnace a layer of initially moist, raw" pellets of finely divided ore material, specifically, Pellets of iron ore concentrates.

In the beneficiation of ores it generally is a prerequisite that the ore material containing the desired mineral component or components be finely divided in order to effect the desired separation as between the mineral component to be concentrated and the undesired or "gangue" component. It necessarily follows that the resulting concentrate of the desired mineral component is in a finely divided form, which prevents the same from being directly usable in a smelting operation. Accordingly, the finely divided concentrate must be agglomerated in some manner.

Thepresent invention is concerned with pelletizatlon as the agglomeration method. By balling up a relatively plastic mixture of concentrate and water of the proper proportions, it is possible to produce therefrom balls or pellets of, say, 0.75 to 1.5 inches diameter, which while having in the moist state a certain degree of mechanical strength, are nevertheless too feeble and fragile to withstand rough handling, and require an induration (thermal hardening) treatment to make them capable of convenient manipulation before and upon arrival at the smelting furnace. When so indurated, the pellets have a mechanical strength comparable to that of fnatural" ore. Various modes of indurating such pellets have been proposed, said methods calling for treatment of the pellets in a vertical (stationary) furnace in the operation of which process layers of the initially moist, raw pellets are laid onto the stockline of a progressively descending column of similar pellets contained in a generally vertical and tubular indurating chamber, through which column a current of heating gas, initially at indurating temperature. is passed in counter-current to the movement of said column, the rate of .descent of the column and the rate of addition of raw pellets to the top of the latter being so adjusted as to maintain a relatively constant height of column in the indurating chamber of the furnace. is of importance that the raw pellets be laid down in an even layer. It is of importance. also, that they be delivered to the furnace and laid down on'the stockline with a minimum of mechanical "abuse (e. g., impaction and compaction).

Accordingly, it

With the foregoing premise in mind, it can I": understood that one of the objects of the present invention is to provide a furnace loading mechanism which will lay a layer of a fluent material, such as pelletized ore concentrates. evenly on the upper exposed surface or stockline of a column of such material, in such manner that the thickness of the layer will be uniform as to depth and density over the whole stockline of the column.

Another inventive object is the provision of a pellet indurating furnace loading mechanism which will deliver raw'peilets to the stockline of a charge in said furnace with a minimum of mechanical abuse or rough handling.

Another object of the invention is to accomplish the latter purpose by a combination of slightly pitched vibrating feeder chutes which, because of being of a sufficient number and of proper interrelation lengthen the path and time of travel of the fragile unfired pellets from the conveyor, which is the point of origin of' the pellets as far as the charging mechanism is concerned, to the furnace in such amounts that said pellets are thoroughly evened as to density and distribution so that they are delivered to the stockline uniformly and without breakage.

Another object of the invention is to provide a pellet indurating furnace loading mechanism comprising a carriage which is arranged for revolution around the mouth of the furnace, on which carriage is mounted a sweep mechanism including a plurality of feeder troughs, the final one of which, namely the one next to the mouth of the furnace, includes a plurality of variously oriented outlet spouts serving to deposit the pellets in a series of circular areas graded as to width to achieve the result of uniform depth of deposited layer. A further inventive object is to provide means for collocating the disorganized pattern of pellets, as received from their point of origin, prior to their delivery onto the final feeder trough just mentioned.

Other objects and advantages will be apparent from a consideration of the following:

The furnaceloading apparatus of the present invention is characterized by a system of vibratory chutes or troughs (the motion of which chutes and the means therefor will be more particularly described hereinbelow) having the following spacial and functional relationships: A stationary conveyor, such for instance as a belt or feeder chute, delivers the raw pellets to a primary revoluble chute carried by a sweep mechanism revoluble over the upper surface (or over a substantial portion of the upper surface) of a aasaue charge contained in the furnace, the delivery being to a locus-adjacent one end of said primary revoluble chuteaxially in line with the center of revolution of said sweep mechanism. The pellets are moved along the primary revoluble chute to a locus, adjacent the other or outer end of the latter, which is in (or substantially in) the plane of the periphery of said charge, and there they are delivered by gravity onto a secondary or delivery revoluble chute (likewise carried by said sweep mechanism) at a locus adjacent the plane of the periphery of the charge. The last mentioned chute has a head zone for receiving the pellets from the primary revoluble chute and a plurality of evenly spaced channels, of varying radial lengths, branching from said head zone, said channels terminating in as may spouts which extend laterally of said delivery chute. The spacial location of the loading mechanism is such that the lower or discharge ends of the discharge spouts are from about 4 to about 2 inches above the "normal stockline of the column.

The above described vibratory chutes are all slightly inclined, but at such a small angle that the pellets of a layer thereon do not tend to roll freely from the high to the low end. Movement of the pellets along the chutes is induced by the use of conventional vibratory feeder means such, for example, as the known electromagnetic vibrators operating on, say, 60 cycle half-wave rectified current. The vibrator is rigidly attached to the chute at a slight angle with respect to the major axis of the chute, so as to give the chute a movement vertical and forward in line with the -magnet; the movement preferably is of the order of inch. at a frequency of about 60 vibrations per second. It has been found that such vibratory chutes positively feed forward the pellets at desirable rates without injuring (breaking, cracking or deforming) the latter; also that the pellets movements over the chute are even and in paths parallel to the major axis of the chute.

The loading mechanism may be, and preferably is, shrouded in a suitable hood or housing (partly revoluble with the sweep mechanism, and partly stationary) for control of the hot, dusty, and steam-laden atmosphere above the charge. Preferably, the above described vibratory means are so located as to lie without (or mostly without) the hood.

This invention will now be described in greater particularity and with reference to the appended drawings, in which:

Fig. 1 is a central, vertical section of a specific furnace loading mechanism illustrative of the principles of the present invention, showing its relationship to the upper end of an indurating furnace. parts being shown in elevation;

Fig. 2- is a plan view of the loading mechanism, the hood structure being omitted;

Fig. 3 is a schematic view of the loading mechanism, depicting the manner of operation;

Fig. 4 is a plan view of the final or lowermost feeder trough of the sweep, illustrating the variously oriented outlet chutes;

Fig. 5 is a side elevation of the foregoing feeder trough:

Fig. 6 is an elevation of the inner end of said trough:

Fig. 7 is a fractional, enlarged plan view of a portion of the lowermost feeder trough, particularly illustrating the adjustment of the entrance vanes, and

Fig. 8 is a vertical section of said feeder troug taken on the line 8-8 of Fig. '7.

In Figs. 1 and 3 of the drawings, l0 designates the mouth of an indurating furnace in which the column ll of pelletized ore concentrate is intended to be kept at a level such as i2. A platform I3, which may or may not be a part of the furnace, provides the support for a single circular track I, concentric with the mouth of the furnace. This track is an element of the invention since it is the foundation on which a carriage, generally designated i5, is mounted for steady revolution over the mouth and on the axis of the furnace. To this end, the carriage has dependent from it a suitable number of wheels it which ride the track. Motion is imparted to the carriage by a hollow shaft l'l which is driven from above by any suitable means (not shown) at any desirable rate, e. g., at the rate of one revolution per minute or at such other rate as may be determined best adapted for any specific installation.

A coupling l8 transfers the motion of the shaft to the carriage. This coupling serves somewhat as a universal joint so that alignment need not be perfect between the rotating hearth and the drive shaft I'I. Both the upper and lower parts of the coupling are bolted loosely through an intermediate plate 18a. The loose bolting permits some relative movement between the two parts, if and when necessary. The shaft and carriage divide between them the support of the feeder sweep, generally designated l9. This sweep virtually is a part of the carriage. Its purpose is to lay a layer of raw, initially moist pellets across the radial dimension of the bed ll. Said pellets are conveyed to the instant mechanism in a damp state which, incidentally, affords a degree of assurance, within limits. that they will retain their bail-shape and not disintegrate, as might be expected from a merely agglomerated volume of moistened ore fines.

Upon arrival at said mechanism the pellets are received from a conveyor at the upper right-hand end of a relatively stationary chute 20 which serves to convey the pellets to the center of the revolving sweep assembly. Chute 20, which thus constitutes the supply means, is vibrated constantly during the passage of the pellets so as to keep them moving. Vibrator 2|, which is the same in type as the vibrators of the sweep feeder chutes, is electromngnetically operated. It is a commercially available device and forms no part of the invention excepting as to its function. and to that end it is sufficient to state that the vibrator is capable of instantaneous adjustment as to rate of vibration by a control at a point either near or remote. Said vibrator is rigidly attached to chute 20 by bridge pieces 22. Suspension means 23 provide the relatively stationary support of the chute but do not interfere with the vibratory action.

The pellets movedown chute 20 at a speed of about thirty feet per minute at a depth of a proximately one and three-ouarter inches, whereu on they are discharged into the primary revoluble receiving chute 24 of the feeder sweep is. From thence the pellets are discharged across the dischar e edge 24a into the secondary and de ivering revoluble chute 25 which makes the final distribution by means of its variously oriented spouts 26 (Fi s. 4. 5 and 6). As the pellets are discharged into chute 24 they assume an irregular or scrambled pattern. due to the fact that chute 20 is stationary and chute 24 is in revolution. But due to the action of the vibrator 21 this initial disorder disappears in a collocaamuse tion or systematization of the pellet stream as it crosses the discharge edge 24a, the same constituting the important function of the upper or receiving chute.

Chute 24 is divided at 2412. the central opening, which is necessary for the admission of the shaft l1 and for spacing chute 24 from the latter, being circumscribed by a short section 240 of pipe which constitutes a fender collar. Flanges along the division of the chute 24 and pipe 240 are clamped together by bolts which produce a unitary structure. The fender collar receives the impact of the pellets discharging from the chute 20, and its use spares the shaft the attrition which the beating pellets would inflict upon it. The collar 240 is easily and cheaply replaced when noticeably damaged. The flanged upstanding sides of the chute 24 are depressed with bevels at 24d so that the projecting lowermost corners of the chute will be cleared when the chute 24 rotates past. The irregular and scrambled pattern assumed by the pellets as they are discharged into the trough 24 is due to the irregular attitude which the chute 24 constantly assumes during its rotation in respect to the chute 20.

As the pellets discharge from chute 24 they leave the latter in a uniform and straight-line pattern laterally of said chute. They enter the secondary chute 25 in the head zone 28 of the guide vanes 23. This zone heads the secondary chute. The line of discharge of chute 24 into chute 25 is virtually coextensive with the width of the latter, since chute 24 is only a little narrower than the chute 25. Therefore, each of the channels delineated by the vanes 29 and the partitions 30, extending inwardly therefrom, receives a substantially identical volume of pe lets. Should any noticeable deviation in volume occur, one or all of the vanes can be adjusted so as to direct more or less pellets to the affected distribution areas.

The structure involving this adjustment is as follows: A slotted bar 3| is welded on top of the flanged perimeter of the outer end of the chute 25 so as to overhang the zone 28. Each of the vanes 29 has a stud 32 welded to its outer vertical end in such an upright position as to project far enough above the upper horizontal edge of the vane to extend through the slot 33 and above the bar 3| where it cooperates with a nut which is adapted to be screwed down against the washer 34. Having swung the vane to its adjustment, the screwing home of the nut pulls the erstwhile free end of the vane up against the bar and sets theadjustment. Arcuate adjustments of the vanesare accommodated by a sufficiently oversized dimension of slot 33, as illustrated at position 29a, Fig. '7.

A hinge, consisting of a knuckle 35 on the inner end of the vane and a pin 86 fastened to the chute, provides for the swinging. The pin consists of a bolt which is inserted through a hole in a cleat 31 on the adjacent partition 30. and is driven through a nut that is welded to the underside of the chute. The upper edge of each vane is notched at 38 and ground round at 39 to provide clearance and minimize impaction of pellets.

Reverting to the description of the secondary chute 25, the channels are identified from #I through #6. These lead to the correspondingly identified spouts 26 which latter are staggered in respect to each other in the radial direction. spouts #2, #4 and #8 pointing in the direction R (Fig. 4) of revolution and spouts #l, #3 and #5 pointing oppositely. The alternately oppositely directed spouts substantially cover the entire upper surface of the charge column, each being conflned to supplying its own circular area, marked on the drawing to agree with channels and spouts.

A heavy center rib 40 continued under the chute as a stiflener divides the chute 25 longitudinally, serving as one of the partitions and the anchorage for a hanger 4|. A pair of hangers 42 connect with the vibrator 43 of the chute 25, and since the vibrator is afllxed to the chute by means of bridge pieces 44, adequate support is provided for the chute. The hangers 42 are suspended from a superstructure 45 that forms part of the carriage. Said superstructure provides a rest for the spring shock absorbers 48 of the vibrator 21, similar shock absorbers 41 supporting the chute 24 on the carriage in proximity to the center shaft. A hood, comprising stationary and revolving components 48, 48a, respectively, mounted on some part of the furnace framework and on the carriage, encloses the mechanism in the manner indicated. The hood hasexternal indentations 4811 at appropriate places in which the vibrators 2| and 21 are situated and thereby the vibrators are shielded from the internal atmosphere of the hood. None of the several openings between the hood and the parts encountered by it are tight; however, since the internal pressure is negative, due to the action of a pump (not shown) applied to the exhaust pipes 430 (Fig. 1), the leakage will be from the outside to the inside. Electrical current is conducted to the three vibrators in known ways. The vibrator 2| being stationary is wired directly to the source. but current conduction to the vibrators 21 and 43since the latter revolve with the carriage-is by means of conductor rings and brushes (neither shown).

The operation of I the mechanism is readily understandable. Moist raw pellets from an external source are delivered to the relatively stationary chute 20. This chute, like the chutes of the revolving sweep, is set at a pitch found from experimentation to be most acceptable for material of the instant kind, such pitch being augmented by constant vibration insuring keeping the mass moving. As the pellets level out in the primary revolving chute 24 they are discharged into the revolving chute 25, whence they are distributed over the closely adjacent top of the charge column in the furnace mouth. The two vibrating feeder chutes 24, 25 have been found necessary to insure the ultimate even distribution of pellets over the stockline. The primary chute vibrates the more or less scram bled volume of pellets into an orderly bed of uniform depth by the time the discharge edge is reached. Having been vibrated into a straightline pattern laterally of the primary chute, the pellets are in the order required for the switching function of the secondary chute. Here the pellets are fanned out, the amount in each'of the channels being substantially the same. It is to be observed that although each of the channels is the same in width and that each receives substantially the same volume of pellets, as just est angular speed must be narrowest in order to lay down its quantum of pellets in a given time interval. The spout #l which moves at the lowest angular speed must be widest in order sufllciently to attenuate its quantum of pellets for delivery in the same time period. The practical effect on the secondary chute 25, in so far as its distributor spout structure is concerned in order to meet the requirement of a uniform depth and density of pellets from center to perimeter of the stockline, is a progressive narrowing of the chutes from center to perimeter.

In addition to the foregoing narrowing of the spouts, there is a gradation in the altitude of their discharge edges. In Fig. 6 it is seen that there is a slight difference in altitude of each discharge edge, beginning with that of the widest spout #I which is highest, and ending with the narrowest spout #6 which is lowest. The four intermediate spouts have discharge edges at levels intermediate #1 and #6. The arrival at this configuration and orientation of the spouts is the result of successful experimentation with moist pelletized ore concentrates.

It can be understood from Fig. 6 and better from Fig. 3 that three of the spouts lay down their streams of pellets in the direction R of revolution (arrows A), while the other three spouts lay their streams of pellets counter to said direction (arrows B). This is a circumstance incidental to the disposition of the spouts, and neither aids nor hinders the formation of a uniform layer of pellets radially of the charge column. This layer, as has been indicated, is circular in form, a further incident which is inescapable from a revoluble feed. The rate of revolution of the feeder sweep is proportioned to the rate of firing of the pellets, and comprises a factor in keeping the upper surface of the pellet column at a substantially constant level.

As will be appreciated from a consideration of the foregoing, the carriage of the sweep mechanism may bedriven by means other than the central vertical shaft specifically illustrated, e. g., by driving means directly associated with the carriage.

We claim:

1. A charging mechanism for fluent material comprising; a sweep revoluble over and about the axis of a determined region, said sweep including an upper primary chute and a lower secondary chute both of which extend in a direction generally radial of said axis, said primary chute having its loading end disposed adjacent said axis and said secondary chute having its loading end disposed beneath the other and discharge end of said primary chute for receiving and reversing the flow of material discharged from said primary chute, said secondary chute having a side delivery for said material; means for depositing said material onto the loading end of said primary chute; and means for vibrating said chutes longitudinally to move said material therealon 2. A charging mechanism for fluent material comprising; a sweep revoluble over and about the axis of a determined region, said sweep including an upper primary chute and a lower secondary chute both of which extend in a direction generally radial of said axis, said secondary chute having its leading end disposed beneath the other and discharge end of said primary chute for receiving and reversing the flow of material discharged from said primary chute, said secondary chute being progressively narrower in the direction away from the loading end thereof and including a discharge edge along one side; means for depositing said material onto the loading end of said primary chute; and means for. vibrating said chutes longitudinally to move said material therealong.

3. A charging mechanism for fluent material comprising; a sweep revoluble over and about the axis of a determined region, said sweep including an upper primary chute and a lower secondary chute both of which extendin a direction generally radial of said axis, said secondary chute having its loading end disposed beneath the other and discharge end of said primary chute for receiving and reversing the flow of material discharged from said primary chute, said secondary chute being progressively narrower in the direction away from the loading end thereof and including a discharge 'edge along each side; means for depositing said material onto the loading end of said primary chute; and means for vibrating said chutes longitudinally to move said material therealong.

4. A charging mechanism for fluent material comprising; a sweep revoluble over and about the axis of a determined region, said sweep including a primary chute inclined downwardly away from said axis having a loading end for said material disposed adjacent said axis and a discharge end disposed adjacent the periphery of said region, and a secondary chute beneath said pri-- mary chute inclined downwardly towards said axis, said secondary chute being progressively narrower in the direction of said axis and including a loading end underlying the discharge end of said primary chute and a discharge edge extending along one side thereof; and means for vibrating said primary and secondary chutes longitudinally to move said material therealong.

5. A charging mechanism for fluent material comprising; a sweep revoluble over and about the axis of a determined region, said sweep including a primary chute inclined downwardly awa from said axis and having a loading end for said material disposed adjacent said axis and a discharge end disposed adjacent the periphery of said region, and a secondary chute beneath said primary chute inclined downwardly towards said axis, said secondary chute being progressively narrower in the direction of said axis and including a loading end underlying the discharge end of said primary chute and discharge edges extending along both sides thereof; and means for vibrating said primary and secondary chutes longitudinally to move said material therealong.

6. A charging mechanism for fluent material comprising; a sweep revoluble over and abouf the axis of a determined region, said sweep including a primary chute inclined downwardly away from said axis having a loading end disposed adjacent said axis and a discharge end disposed adjacent the periphery of said region, and a secondary chute beneath said .primary chute inclined downwardly towards said axis, said secondary chute being progressively narrower in the direction of said axis and including a loading end underlying the discharge end of said primary chute and discharge edges along both sides thereof; means stationary relative to said sweep for depositing said material onto the loading end of said primary chute throughout the circular path thereof; means for vibrating said primary chute longitudinally to move and collocate at its discharge end the material deposited thereon at the other end, and means for vibrating said secondary chute to move said collocated material longitudinally therealong from the loading end and discharge the same from the side edges thereof.

7. A charging mechanism for fluent material comprising; a sweep revoluble over and about the axis of a determined region, said sweep including a primary chute having a loading end disposed adjacent said axis and a discharge end disposed adjacent the periphery of said region, and a secondary chute beneath said primary chute, said secondary chute being progressively narrower in the direction of said axis and including a loading end underlying the discharge end of said primary chute and a discharge edge along the narrowing side thereof; means stationar relative to said sweep for depositing said material onto the loading end of said primary chute throughout the circular path thereof; means for vibrating said primary chute longitudinally to move and collocate at its discharge end the material deposited thereon at the other end, and means for vibrating said secondary chute to move said collocated material longitudinally therealong from the loading end and discharge the same from the narrowing side edge thereof.

8. A charging mechanism for fluent material comprising; a sweep revoluble over and about the axis of a determined region, said sweep including a primary chute inclined downwardly away from said axis having a loadin end disposed adjacent said axis and a discharge end disposed adjacent the periphery of said region, and a secondary chute beneath said primary chute inclined downwardly towards said axis, said secondary chute having a loading end underlying the discharge end of said primary chute and a plurality of longitudinal channels extending from said loading end, said channels varying in length and terminating in side delivery spouts; means stationary'relative to said sweep for depositing said material onto the loading end of said primary chute throughout the circular path thereof; means for vibrating said primary chute longitudinally to move and collocate at its discharge end the material deposited thereon at the other end, and means for vibrating said secondary chute to move said collocated material longitudinally along said channels from the loading end for discharge from said spouts.

9. A charging mechanism as defined in claim 8 wherein said spouts narrow progressively in a direction away from the axis of said region to compensate for correspondingly increasing peripheral sweep speeds.

10. A charging mechanism as defined in claim 8 wherein the channels in said secondary chute are constituted by the bottom thereof in combination with upstanding adjustable vanes.

11. A charging mechanism tor a stationary ver- 10 tical furnace having a top mouth comprising; means for discharging fluent material continuously in the direction of said mouth adjacent the axis thereof; and a sweep disposed between said material discharge means and furnace mouth and revoluble about the axis of said mouth for spreading said material in a continuing layer, said sweep including, an upper primary chute and a lower secondary chute both of which extend in a. direction generally radial of saidaxis, said primary chute'havin its loading end disposed adjacent said axis beneath said material discharge means and said secondary chute having its loading end disposed beneath the other and discharge end of said primary chute for receiving and reversing the flow of material discharged from said primary chute, said secondary chute being progressively narrower in the direction away from the loading end thereof and including a discharge edge along one side, and means for vibratin said chutes longitudinally to move the material therealong.

12. A charging mechanism as defined in claim 11 and which further includes a hood shrouding said sweep and having a component revoluble therewith, and hanger means movably suspending said chutes and vibrator means from said revoluble hood component.

13. A charging mechanism for fluent material comprising; a sweep revoluble over and about the axis of'a determined region, said sweep including an upper primary chute inclined downwardly away from said axis having a loading end disposed adjacent said axis and a discharge end disposed adjacent the periphery of said region, and a secondary chute beneath said primary chute having a loading end underlying the discharge end of said primary chute for receiving and reversing the flow of material discharged from said primary chute, said secondary chute being downwardly inclined and having a side delivery for said material; means for depositing saidmaterial onto the loading end of said primary chute; and means for imparting a vibratory motion to said chutes to move said material therealons.

ERNEST G. on CORIOLIS. ROLLIE P. CAMPBELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATIENTS Number Name Date 836,888 Parker Nov. 27, 1908 1,791,628 MacMichael Feb. 10, 1981 2,219,954 Geiger et a1. Oct. 29, 1940

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