US3131244A

US3131244A - Sintering machine

Info

Publication number: US3131244A
Application number: US790943A
Authority: US
Inventors: Kuriyama Shunji; Fujii Yukio; Numata Takehisa; Ando Ryo
Original assignee: Nippon Kokan Ltd
Current assignee: JFE Engineering Corp
Priority date: 1958-02-04
Filing date: 1959-02-03
Publication date: 1964-04-28
Anticipated expiration: 1981-04-28

Description

April 23, 1964 SHUNJI KURIYAMA ETAL 3,131,244

SINTERING MACHINE 4 Sheets-Sheet 1 Filed Feb. 3, 1959 5 U INVENTOR. vm A M a M j Ma S. m

April 28, 1964 SHUNJl KURIYAMA ETAL 3,131,244

SINTERING MACHINE 4 Sheets-Sheet 2 Filed Feb. 5, 1959 April 28, 1964 SHUNJI KURIYAMA ETAL 3,131,244

SINTERING MACHINE Filed Feb. 5, 1959 4 Sheets-Sheet 4 I INVENIOR. H

ww ww;

United States Patent 3,131,244 SINTERING MACHXNE Shunji Kuriyama and Ynlrio Fujii, both of Tokyo, and Tairehisa Numata and Rye Ando, both of Yokohama, Japan, assiguors to Nippon Kohan Kabnshiiri Kaisha, Chiyoda-ku, Tokyo, Japan Filed Feb. 3, i959, ar. No. 7%,943 Claims priority, application .iapan Feb. 4, 1958 8 Claims. (Ci. 265-21) The invention relates to sintering machines and more particularly to sintering machines of the type employed in the beneficiation of iron ore and similar raw materials in processes of extractive metallurgy.

Sintering machines of this type now commonly employed use a plurality of pallets or perforated carriers on which the material to be sintered is carried past an ignition burner and thereafter over a wind box by means of which air is drawn through the ignited charge either in an updraft or downdraft arrangement, whereby the heat generated by reaction of oxidizable material in the sintering charge with a stream of air causes the material to reach the temperature of incipient fusion and to agglomerate. Cooling usually takes place outside the sintering machine. For this purpose, the material is discharged from the pallets and cooled outside the sintering machine proper.

The pallets of conventional sintering machines return in upside-down position from a discharge zone in which either hot sintered material or pre-cooled material is discharged from the pallets to the charging area where a fresh layer of material is placed on the pallets and the cycle is repeated. The return path of the pallets is of substantially the same length as the working path so that in conventional sintering machines, the pallets are idle during one-half of their travel. Because of their weight and size, the pallets and the conveyor on which they travel account for a substantial portion of the first cost of a sintering machine of the type 'dmcribed. Having substantially one-half of this equipment idle during operation of the plant appears to be uneconomical.

If it is desired to increase the capacity of a sintering plant operating on the principle described above, it is either necessary to duplicate existing machinery or to rebuild it to such an extent as to require prolonged shutdown.

Sintering machines of conventional design require a large amount of floor space or great height for a given capacity because of the need for returning the pallets empty from the discharging area to the charging point.

An object of the present invention is, therefore, to provide a sintering machine making fullest possible use of the space occupied by the machine for productive purposes.

Another object is the provision of such a machine which can readily be expanded for increasing capacity thereof without requiring a prolonged shutdown period.

Yet another object is the provision of a sintering machine in which the pallets carry a charge substantially over their entire path of travel.

With these and other objects in view, the present invention provides for a sintering machine having a plurality of pallets, a sintering zone, a cooling zone and a continuous pallet conveyor for conveying the pallets. The pallet conveyor of the sintering machine includes two reversal sections and two elongated sections connecting the reversal sections. At least a portion of each of the two elongated sections is located in the sintering zone or the cooling zone, or both. The conveyor moves the pallets in a closed path from one of the reversal sections over one of the elongated sections to the other one of the 333L244 Patented Apr. 28, 1964 "ice reversal sect-ions and therefrom back to the first-mentioned reversal section over the other elongated section. While the pallets are moved over each of the elongated conveyor sections, they are thus passed through the sintering zone or the cooling zone, or both.

During such travel, the pallet means are kept with their top side facing upward while travelling over the elongated sections so that a charge may be carried on the top side during both movements of the pallets between the two reversal sections.

In a preferred embodiment of the invention, the two elongated conveyor sections are placed on different levels in substantially superimposed relationship. It is furthermore preferred that a portion of the lower one of the superimposed elongated sections be located in the sintering zone and a portion of the upper conveyor section in the cooling zone.

According to another preferred embodiment, the two elongated conveyor sections may be juxtaposed on substantially the same horizontal level.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

PEG. 1 is a plan view of a preferred embodiment of a pallet used in the sintering machine of the invention;

FIG. 2 is a somewhat schematic side elevation of a preferred embodiment of a sintering machine;

FIG. 3 is a side-elevational view of a detail of another sintering machine of the invention;

PEG. 4 shows a third embodiment of a sintering machine of the invention in fragmentary side-elevational view;

FIG. 5 shows yet another embodiment of the invention in fragmentary side-elevational view;

FIG. 6 is a plan View of a preferred embodiment of the sintering machine of the invention in which the elongated conveyor sections are juxtaposed in substantialiy the same plane;

FIG. 7 is an elevational cross-sectional view of the device of FIG. 6 taken on the line 1-1;

FIG. 8 is an elevational cross-sectional view of the device of FIG. 6 taken on the line IIII;

FIGS. 9-13 schematically illustrate several arrangements of the operating zones of sintering machines of the type shown in F168. 6-8 having two or more elongated conveyor sections;

FIG. 14 shows a detail of the sintering machine illustrated in FIGS. 6-8 on an enlarged scale;

FIG. 15 is a detail view in side elevation of a pallet discharging device;

FIG. 16 is a plan view of a modified pallet; and

FIG. 17 is a side-elevational view of a device for discharging the pallet of FIG. 16.

Referring now to the drawings, and more particularly to FIG. 1, there is shown a pallet 9 provided with roller pairs 10, ll, 12 rotatably secured to the sides of pallet 9. A roller shaft 14 projecting laterally from each of the sides or" pallet 9 carries the two rollers 10 which are arranged closely adjacent the side of pallet 9. A second roller shaft 13 jointly carries respective members of roller pairs 11 and 12 on opposite sides of pallet 9. Rollers 1!. are spaced from the side of pallet 9 a distance greater than the width of rollers 1i Rollers 12 are mounted on shaft 13 outside of rollers 11.

The pallet conveyor of a preferred embodiment of the sintering machine of the invention and associated ele- 3 ments of the sintering machine are shown in FIG. 2 in somewhat schematic side-elevational view. The pallets 9 of the sintering machine are shown to travel along a closed path the various stations of which are designated by lower case letters.

While travelling between positions I) and c, rollers 10 and 12 of pallets 9 are respectively supported on straight conveyor tracks 15 and 16. The number of pallets is such that they abut against each other during their travel along the straight track portions. Movement of the pallets is actuated by a driven sprocket 19 engaging rollers 11 of the pallets so as to push the same onto the tracks 15 and 16.

During travel over the track section bc, rollers 19 support the front portion of the pallet, and rollers 12 the rear portion in the direction of movement.

Shortly before reaching the end of the straight portions of tracks 15 and 16, the pallets are seized by the teeth of sprocket wheel 20 which engage rollers 11 and carry shaft 13 and the portion of pallet 9 to which shaft 13 is attached through an arcuate path about the periphery of sprocket wheel 29 to a point d located diametrically opposite point c and above the latter.

While the pallets 9 are lifted from c to d by engagement of the teeth of sprocket wheel 20 with rollers 1-1, rollers 12 travel on the inside of the arcua-te portion of track 16. On their travel beyond a point radially spaced from the center of rotation of sprocket wheel 21) in a horizontal direction, rollers 12 are supported by a downwardly inclined portion of a track 18. which is arranged within the arc of track 16.

During movement of rollers .11. and 12 in an arcuate path about sprocket wheel 20, rollers at first travel along a downwardly sloping portion of tracks 15 toward a point f, at which point they make contact with a track portion 17 leading them in an upward direction, and in an arcuate path about sprocket =Whl in such a manner that rollers 10 reach point h on track 17 spaced horizontally from point d on track 18 when rollers 11 and 12 reach position d.

By this arrangement of the track sections guiding rollers 10 over the path cfh, the pallet is first tilted to discharge any material held on the top surface thereof and is then restored to a horizontal posit-ion for return travel from sprocket wheel 2% toward sprocket wheel 19 in a path substantially parallel and superimposed upon the straight elongated section of tracks 15 and 16 between points [2 and c, with rollers 12 and 11 arranged ahead of rollers 10 in the direction of travel.

During the return movement of pallets 9, rollers 10 move on a straight portion of track 17 from d to e, and rollers 11 and 12 on a straight portion of tracks 18. As the pallets reach point i, shortly before arriving at the end point e of the straight return track sections, they are engaged by driven rollers 21 rotatable about a vertical axis and cooperating with the sides of the pallets above

rollers

10, 11, and 1 2 to accelerate them to a speed greater than the speed of travel actuated by engagement of the teeth of sprocket wheel 20* with rollers 11 which causes a continuous chain of pallets to be pushed along tracks 17 and 18 from point d towards point e. The pallet 9 engaged by rollers 21 is thus separated from the succeeding pallet.

The pallets are moved from point e at the highest point of the circumference of sprocket wheel 19 in an arcuate path to the lowermost point b on sprocket wheel 19 by engagement of rollers 12 in the teeth of sprocket wheel 19 which cause rollers 12 to travel in a substantially circular are about the axis of rotation of sprocket wheel 19. Rollers 11 initially travel along a similar arcuate path until they reach point k wher they are transferred to arcuate portions of tracks 16 and 13.

Immediately beyond point e the tracks 17 slope sharply downward so that rollers 1%} which travel along track 17 are moved to a position lower than the corresponding position of rollers 11 and 12 and the top side of pallet 9 is tilted downward to discharge any material held thereon.v During their continued travel toward point [1, the rollers 19, 11 and 12 are gradually returned to an even level which is reached when rollers 11 are in position k.

In order to hold rollers 12 securely during their movement about sprocket wheel 19, the sprocket wheel is provided with two sets of teeth, the teeth 7 of one set being longer than the teeth 8 of the other set together with which they form recesses 6 for engagement with rollers 12.

When a pallet reaches position k, it makes contact with the last pallet of the series of pallets located on the conveyor section between points 17 and c and pushes the entire series of pallets towards sprocket wheel 20.-

While the pallets are moved along the conveyor arrangement described above, the sintering operation is performed as follows:

A hearth layer of partly reacted material isdeposited on the pallets at the beginning of their straight path from b to c by means of a charging device 22 which may be a portable conveyor or vibrating feeder drawing hearth material from a suitable storage bin (not shown). Themixed charge of material to be sintered is supplied by an additional feeding device 23 which discharges the material upon a baffle plate 24 from which it is spread over the previously deposited hearth layer and is leveled to uniform thickness by the lower edge of plate 24 which con-.v stitutes a leveling bar.

The charged pallets then travelunder an ignition furnace 25 by means of which the mixed charge is ignited. It is kept in incandescent condition by a stream of air passed through the charge as will become apparenthereinafter until the pallets reach point 0.

By the downward tilting of the top side of pallets 9 during their travel about sprocket wheel 20, the sinteredmaterial is discharged into a chute 26 and is crushed by crusher 27 from which it drops into a hopper 28. It is withdrawn from there by an elevator 29 such as a skip from which it is dropped into the hopper 30 and placed on a screen 31 which separates the sinter from thereturn,

The sinter is charged onto the pallets a point d and permitted to cool while traveling from d. to e.

Tilting of the pallets during their travel about sprocket.

wheel 19 in the manner described above causes the cooled sinter to be discharged into the hopper 32 from: Where it may be conveyed out of the sintering machine by means.

of conveyor 33.

It will be. understood that grid bars may be employed;

in the well known manner in place of the chute 26. for separating the sinter from the return.

The necessary draft of air for sinteringv the charge and for cooling the sintered material is provided by an ar-.

rangernent which includes a wind chamber 36 having front and rear walls 34 and side walls 35. The top and bottom of wind chamber 36 are formed by the pallets traveling over the upper and lower elongated sections of the pallet conveyor, respectively. A. wind box 37, is

arranged under thelower elongated conveyor section and communicates with a duct 38.

Outside air is drawn through the layer of hot sinter on the pallets between points d and e into the wind chamber 36. It then passes through the ignited charge on the pallets between points b and c to maintain the oxidation reaction in the charge.

in the usual manner.

A conveyor 39 is located on the bottom of wind box 37 for the removal of dust. The downdraft produced in wind a The hot air together with the products of combustion is exhausted through the duct 38 The wind box 37 extends in a direction toward sprocket l9 beyond the front wall 34 of wind chamber 36 so as to draw air and hot gases from ignition furnace 25 into wind box 37 to cause ignition of the charge on pallets 9 and to remove dust from the area adjacent the outside of wall 34.

The reversal section of the pallet conveyor of FIG. 2 constitued by sprocket wheel 19 and the elements cooperating therewith may be modified to permit immediate separation of the cooled sinter from fines which are directly returned to the conveyor to form a hearth layer on the pallets. Such a modification is illustrated in FIG. 3 in which a vibratory screen 40 is located below hopper 32 to receive the material discharged from pallets 9. The undersize material drops through the screen directly on the pallets whereas the sinter retained on the screen is discharged onto a conveying mechanism 41 which may be a vibrating feeder or continuous conveyor which carries the sinter out of the machine.

A further modified embodiment of the sintering machine is shown in the fragmentary representation of FIG. 4. The pallets 9 move in a closed circuit between points I, m, n, 0, and l. Between 1 and m, the pallets are driven in a horizontal path by engagement of sprocket wheel 42 with the rollers 11 of the pallets, and rollers 10 and 12 travel on tracks 43 and 44, respectively.

During reversal of the pallets between m, p, and n, the pallets are discharged in a manner similar to that shown in FIG. 2. The rollers 11 are pulled up by teeth 46 of sprocket wheel 45. The pitch of teeth 46 is greater than the length of a pallet in order to prevent collision of each pallet with the ones preceding and following it. Rollers 12 are led from rails 44 along the circumference mpn of sprocket wheel 45 and are engaged with rails 48 to reach the position at n. This arrangement somewhat simplifies the path of rollers 10. The section n to of the pallet conveyor is downwardly inclined in a straight line. It is equally possible to have the elongated upper conveyor portion sloping downward from n to q only and to have it extend horizontally from q to 0. In the first arrangement, the pallets are moved from n to 0 by gravity only. In the second arrangement, engagement of the sprocket wheel 45 with the rollers of the pallets at q pushes a chain of pallets toward point 0.

With either arrangement, the sinter is discharged while the pallets travel from point 0 to point I over substantially one-half of the circumference of sprocket 42. In order to discharge the pallets during their arcuate travel about the sprocket wheel, the rollers 11 and 12 move in the same manner as indicated above in connection with FIG. 2, that is, in a substantially circular arc. Rollers 10 are guided about the circumference of sprocket wheel -32. substantially from 0 to r and are then diverted inwardly toward the axis of rotation of the sprocket wheel along rails 43 so that they reach the rails of the lower elongated section of the pallet conveyor ahead of rollers 11 and 12.

In the arrangement illustrated in FIG. 4, the sintered material is dropped from the pallets onto a hopper 32' arranged on the outside of the sintering machine and the sintered product is then further treated in a known manner.

FIG. illustrates a modification of a portion of the device of FIG. 4. In this arrangement the material sintered during travel of the pallets along tracks 1 in the lower elongated conveyor section is transferred together with the pallets to the tracks 2 of the upper elongated conveyor section. There is no discharge from the pallets at the reversal section and cooling takes place substantially entirely in the upper elongated conveyor section.

The pallets 9 are transferred from the end point t of tracks 1 to pallet carriers 55 suspended between two wheels 53. The pallet carriers 55 are pivotally supported at points 54 of the wheels 53 by means of bars 51 and are thus carried in a circular path about the axis of rotation 52 of wheels 53. The pallets 9 are transferred from the end point t of track 1 to a carrier 55 when it is in position 11 by means of a roller track 50 which moves up and down. The width of the roller track 59 is somewhat less than that of the pallet 9. The pallet 9 is secured on the carriers 55 by its rollers 3 and 4. During the rotation of wheels 53, pallets 9 remain in their upright position until they reach point v where they are pushed off carriers 55 by the action of vertically oscillating roller conveyor 56 and are transferred to upper conveyor tracks 2 at w. Suitable collecting means such as hopper 57 may be arranged along the arcuate path of the pallets in the reversal section to receive sinter spilled from the gaps between the pallets.

FIGS. 6-8 illustrate an embodiment of the invention in which the pallets travel substantially in a single horizontal plane in a continuous path leading through a sintering and cooling zone.

This embodiment of the sintering machine of the invention is illustrated in FIG. 6 in plan view, whereas FIG. 7 shows a side-elevational sectional view of the sintering zone and of associated elements, and FIG. 8 shows a corresponding section through the cooling zone.

The pallets 61 traveling over the conveyor illustrated are shown in more detail in FIG. 16 and differ from those of FIG. 1 in the arrangement of the rollers. One shaft carries a roller 121 whereas another shaft spaced from the first shaft in direction of travel of the pallet carries a roller 122 equally spaced from the side of pallet 61 as roller 121, and a third roller 123 arranged outside of roller 122.

The pallets 61 are moved in a substantially horizontal rectangular circuit along a continuous path indicated by reference characters a'-h'. The mixture to be sintered is charged on the pallets between points a and b of the long leg a--d of the rectangular conveyor path. The charge is sintered by the downdraft between b and c and the sinter is discharged between points c and d.

The heated sinter is returned to the pallets between points e'-f' of the other long leg e-h' of the conveyor path. The sinter is cooled by an updraft of air in section fg and is discharged in cooled condition between points g and h. The pallets 61 are transferred from one long leg to the other over the short legs d'e and h'a of the rectangular conveyor path.

The pallets 61 are pushed along the elongated straight conveyor sections by sprocket wheels 62 and 63 best seen in FIGS. 7 and 8, respectively. They are transferred from one elongated conveyor section to the other in a reversal section of the conveyor by means of transfer trucks 197. Movement of the pallets from the trucks to the long conveyor legs is partially actuated by sprockets 62 and 63 and aided by

pushers

66 and 67 which ensure engagement of the pallets by the teeth of sprocket wheels 62 and 63.

Pressure rollers

68 and 69 rotating about vertical axes and cooperating with the sides of pallets 61 further assist in guiding the pallets onto the long legs of the conveyor.

Discharge of the material carried on pallets 61 and transfer of the pallets to the transfer trucks for transverse movement from one long conveyor leg to the other is performed by means of a rotating and transferring mechanism 7 0, 71, which will be described in more detail below.

Feeders 73 arranged ahead of the sinter zone deposit a hearth layer of material on pallets 61 from storage hoppers 72. Feeders 76 place a layer of mixed material to be sintered on top of the hearth layer. This mixed material may consist either of finely ground iron ore or of waste material collected in other stages of ore processing and may contain a mixed carbonaceous fuel. This mixture, the nature of which is well known, may be prepared in a separate operation not part of this invention and not illustrated, and is supplied to the sintering machine by means of conveyor 74 which drops it into hopper 75 from which it is released by feeder 76 to drop on a baffle plate 77 from which it is spread on top of the hearth '3' layer already present on the pallets. The lower portion of baflle plate 77 acts as a leveling bar to maintain a fixed uniform depth of charge on the pallets.

The material is next ignited by ignition furnace 7 3 and remains at a high temperature while traveling from b to c because of a downdraft of air indicated by the arrows in FIG. 7. The air is drawn through the charge and the pallets 61 into a wind box 79 from which it is withdrawn through a duct 80.

The material is discharged after sintering in a manner which will be described later. It drops onto a crusher 81 in which it is broken up. The output of crusher 81 is divided into two parts by a screen 82. The sinter is retained on the screen, whereas the fines passing through the screen drop into return hopper 83 and are carried out of the machine by conveyor 84. The sinter drops into a hopper 85 and is transferred to sinter hopper 87 by bucket elevator 86.

As best seen in FIG. 8, the hot sinter drops from hopper 87 onto pallets 61 at f and the stream of sinter fed to the pallets is controlled by feeding device 83. While the pallets travel from f to g, the hot sinter is cooled by an upward draft of air is indicated by the arrow marks in FIG. 8. The air thus heated is exhausted by the hood 89 and through a duct 90.

The sinter after being cooled is discharged from pallet 61 and is separated by the double-deck screen 91 into three portions. The final sinter product which is coarsest is retained on the upper screen. It is collected in chute 92 and carried out of the machine by the product conveyor 93. Hearth layer material of intermediate size passes through the upper screen and is retained on the lower screen for discharge through hopper 94 and chute 95 from which it is transferred to hearth layer hopper 72 by a bucket conveyor 96 and chute 97. The fines passing through the lower screen are directed out of the sintering machine by the conveyor 99 on which they are dropped by hopper 98 and from which they are discharged on conveyor 84 by means of chute 100.

Material spilt from the pallets in conveyor section ac' is collected by a conveyor 101 located at the bottom of wind box 79 and is discharged by means of chutes 102 and 103 onto return conveyor 84. Conveyor 99 passes from the double-deck screen mentioned above below section e'-g of the pallet conveyor so as to collect any material spilling from the pallets while traveling through the cooling zone. All these materials are finally discharged onto the return conveyor 84 for further processmg.

The conveyor 101 in the wind box 79 is preferably protected from direct impact of the red-hot particles dropping from pallet 61 in the sinter zone by a baflle plate 105.

The devices employed for tilting the pallets and for transferring them from one of the long legs of the pallet conveyor of FIGS. 6-8 to the other long leg are illustrated in FIGS. 14, 15 and 17.

One embodiment of the device suitable for discharging material from a pallet is illustrated in FIG. 14. The pallet 61 is equipped with gearing indentations 108 on both sides for engagement with corresponding coupling members 109 on shafts 111 which also carry pinions 110 fixedly fastened to coupling members 169. The shafts 111 are supported by bars 112 on either side of pallet 61. When a pallet reaches the end of a wind box, shafts 111 move along the side of the pallet 61 until coupling members 169 drop into the recesses 108 of the pallet. The pallet is now coupled to pinions 110 and secured against rotation with respect to the pinions. During continued translatory movement of shaft 111 taking along pallet 61, pinions 116 are engaged by racks 113 which are fixedly fastened on the conveyor frame. The rotation of pinions 110 which is thus induced,

tilts the pallets to drop their charge. and returns them again to an upright position.

After completion of a full turn of the pallet 61, the

racks 113 release the pinions 116 and continued movement of bars 112 pushes the pallets forward until they are placed on top of the transfer trucks 167 for transverse movement along tracks 106. Bars 112 together with the shafts 111 and pinions are then returned to their original position. The direction of rotation of the pallets 61 during this discharging operation may be selected by placing the racks 113 either above or below pinions 110.

A different mechanism for tilting the pallets 61 is illustrated in FIG. 15 which shows a pallet rotating drum 114 and rails 115 having a fixed section on the left of the drum 114 as shown in the drawing and leading from the edge of the wind box to the drum. Another section of rails 115 is located in the drum, and a second fixed section of rails 115 leads from the drum towards a transfer truck 64.

The drum 114 is equipped with guide rails 117 upward-' ly spaced from rail section 115 in the upright position of the drum. The guide rails 117 are also located slightly above the pallet rollers 116 for engagement therewith p when the pallet is tilted. Catches 118' hold the pallet in position during movement of the drum in the direction of the arrow. The material held on the top side of the pallet is discharged during the rotation of drum 114 through an angle of approximately 90 and the drum then returns to release the pallet so it may move under its own gravity onto the truck 64 until it is stopped by abutment against buffer 119.

It will be understood that the same function may be carried out by a section of track rotatable about a pivot without a drum 114. The rotatable track section has to be equipped with suitable securing means similar to rails 117 and catches 118 for holding the pallet during rotation.

FIG. 17 shows yet another embodiment of a tilting mechanism for operation with the pallet 61 of FIG. 16.

The device of FIG. 17 comprises a sprocket wheel 124 having teeth 125 formed with arcuate recesses shaped to match the circumference of rollers 123. As pallets 61 move along tracks 126, rollers 123 are engaged by the mating recesses of teeth 125 and are moved upwardly in an arcuate path while rollers 121 continue in a straight direction along tracks 126. The pallets 61 are thus tilted to discharge the material held on their top surface. Sprocket wheel 124 moves the pallet 61 forward at an accelerated pace and finally transfers it onto transfer truck 127. The track 126 preferably slopes slightly upward towardwheel 124 so that a pallet may be pulled away from a string of pallets by the sprocket wheel 124 and friction between this pallet and the succeeding one which might damage both pallets is avoided.

A plurality of elongated conveyor sections of the type The direction of movement of the pallets is indicated by arrows in FIGS. 913.

FIG. 9 shows a combination of the pallet conveyor arrangement of FIGS. 6-8 with an additional sintering zone. The conveyor arrangement of FIG. 9 comprises three long conveyors legs joined at their ends by two short transverse conveyor sections. Pallets move from two charging zones at respective ends of the outer long legs through respective sintering and discharge zones into one of the transverse legs where they are moved by means of trucks towards a central long conveyor leg in which the sinter produced in the outer legs is returned to the pallets which converge from both outer legs onto the central leg. While moving over the central leg at twice the speed maintained on the outer legs, the pallets carry the sinter through a cooling zone and discharge it at the end of the central long leg whereupon they are returned alternatingly to the two outer legs by a reciprocating truck arrangement.

The modifications of the embodiment of the invention illustrated in FIGS. and 11 do not involve more than two long conveyor legs, but are representative of some of the functional variations to which the sintering machine of the invention lends itself.

The device illustrated in FIG. 10 has two identical long legs each comprising a charging, a sintering, and a discharging zone. In this embodiment of the invention, cooling of the sinter is performed outside the machine proper. Still, substantially the entire path of the pallets is utilized for productive purposes.

In the embodiment illustrated in FIG. 11, each long leg of the conveyor leads through a charging zne, a sintering zone, a cooling zone, and a discharging zone, performing the full processing cycle in each one of the two elongated conveyor sections.

The embodiments of FIG. 10 and FIG. 11 permit the simultaneous sintering of two different charges on the same machine.

FIGS. 12 and 13 show examples of expanded sintering plants built around an older installation to increase the productive capacity of any one of the arrangements illustrated in FIGS. 6-11. In these examples, the processing steps are performed in four long conveyor sections, and empty pallets are returned at four times the speed along one long leg of a five-track arrangement. While the productive capacity of the central track is lost, such an arrangement may still be found advantageous in large scale operation and permits transverse alignment of the various processing stages of the pallet conveyor tracks on the individual long legs of the pallet conveyor.

It will be appreciated that the pallets in the sintering machine of the present invention are utilized to a degree not available with sintering machines of the prior art. Movement of empty pallets is minimized and may actually be entirely avoided by utilizing some of the modifications of the machine of the invention. For a given capacity, the number of pallets may thus be reduced to substantially one-half as compared to conventional sintering machines, and over-all dimensions of the machine may be reduced correspondingly, resulting in a lower first cost of the inventive device. Such decreased size leads to reduced operating cost and improved operating efficiency.

It will be understood that each of the element described above, or two or more together, may also find a useful application in other types of sintering machines differing from the types described above.

While the invention has been illustrated and described as embodied in sintering machines for the processing of iron ore, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others Can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. In a sintering machine, in combination, a plurality of pallet means; a sintering zone; a cooling zone; con tinuous pallet conveyor means for conveying said pallet means, said conveyor means including two reversal sections and two elongated sections connecting said reversal sections, said elongated sections being located in said zones, respectively, said conveyor means being adapted to move said pallet means in a closed path from one of said reversal sections over one of said elongated sections to the other one of said reversal sections and therefrom to said one reversal section over the other one of said elongated sections, whereby said pallet means are passed though said zones while being moved over each of said elongated conveyor means sections, charging means for successively charging said pallet means with material to be sintered and igniting means for igniting said material located relative to said conveyor means to ignite the material when said pallet means enter said sintering zone; means for blowing a stream of air through said pallet means in said sintering zone to increase combustion; crushing means at the end of said sintering zone for crushing the sintered material into crushed matter containing sinter; separating means for separating sinter from other crushed matter; means for placing said sinter successively on said pallet means when the same enter said cooling zone so that said sinter is cooled; and means for removing the cooled sinter when said pallet means leave said cooling zone.

2. In a sintering machine, in combination, a pluraltiy of pallet means; a sintering zone; a cooling zone; continnous pallet conveyor means for conveying said pallet means, said conveyor means including two reversal sections and two elongated parallel ections connecting said reversal sections, portions of said elongated sections being located in said zones, respectively, said conveyor means being adapted to move said pallet means in a closed path from one of said reversal sections over one of said elongated sections to the other one of said reversal sections and therefore to said one reversal section over the other one of said elongated sections, whereby said pallet means are passed through said zones while being moved over each of said elongated conveyor means sections; means for tilting said pallet means in at least one of said reversal sections at the end of said sintering zone; charging means and feeding means at the other reversal section located between said longitudinal parallel sections for successively charging said pallet means with material to be sintered; igniting means for igniting said material located relative to said conveyor means to ignite the material when said pallet means enter said sintering zone; means for blowing a stream of air through said pallet means in said cooling and sintering zones transversely to said elongated parallel sections to cool and to increase combustion; crushing means at the end of said sintering zone for crushing the sintered material into crushed matter containing sinter, said crushing means being located for receiving sintered material from pallet means tilted in one reversal zone; separating means for separating sinter from other crushed matter; means for placing said sinter successively on said pallet means when the same enter said cooling zone so that said sinter is cooled; and means for removing the cooled sinter when said pallet means leave said cooling zone.

3. In a sintering machine, in combination, a plurality of pallet means; a sintering zone; a cooling zone; continuous pallet conveyor means for conveying said pallet means, said conveyor means including four reversal sections and three elongated parallel sections connecting said reversal sections, portions of said elongated sections being located in said zones, respectively, said conveyor means being adapted to move said pallet means in a closed path from either one of two of said reversal sections over one of said elongated sections to either one of the other two of said reversal sections and therefrom to one of said firstmentioned two reversal sections over one of the other two ll of said elongated sections, whereby said pallet means are passed through said zones while being moved over each of said elongated conveyor means sections; charging means and feeding means at the other reversal section located between said longitudinal parallel sections for successively charging said pallet means with material to be sintered; igniting means for igniting said material located relative to said conveyor means to ignite the material when said pallet means enter said sintering zone; means for blowing a stream of air through said pallet means in said cooling and sintering zones transversely to said elongated parallel sections to cool and to increase combustion; crushing means at the end of said sintering zone for crushing the sintered material into crushed matter containing sinter; separating means for separating sinter from other crushed matter; means for placing said sinter successively on said pallet means when the same enter said cooling zone so that said sinter is cooled; and means for removing the cooled sinter when said pallet means leave said cooling zone.

4. In a sintering machine, in combination, a plurality of pallet means; a pair of co-extensive track means for supporting said pallet means, one of said track means constituting a sintering zone and the other track means constituting a cooling zone; a pair of moving and reversing means at the ends or" said track means for pushing pallet means in end-to-end relationship along said track means, and for reversing each pallet means at the ends of said track means; charging means for charging said pallet means with material to be sintered and igniting means for igniting said material located at one end of one of said track means to ignite the material on pallet means entering said sintering zone; means for blowing a stream of air transverse to said track means through said pallet means and material thereon in said sintering zone; separating means at the other end of said one track means for separating sinter from the sintered material; means for placing said sinter successively on pallet means on the other track means when said pallet means enter said cooling zone so that the sinter is cooled; and means for removing the cooled sinter from said pallet means at the end of said cooling zone.

5. In a sintering machine, in combination, a plurality of unconnected pallet means; a pair of co-extensive track means for supporting said pallet means in end to end relationship, one of said track means having a major portion extending from one end thereof and constituting a sintering zone and the other track means having a major portion extending from one end thereof and constituting a cooling zone, said cooling and sintering zones having ends spaced from the other ends of said track means; a pair of moving and reversing means at the ends of said track means for pushing pallet means in end to end relationship along said track means, and for reversing each pallet means at the ends of said track means, each moving and reversing means maintaining each pallet means with the same side up and including means for separating each pallet means from the pallet means directly trailing the respective pallet means before reversing the respective pallet means; charging and feeding means for charging said pallet means with material to be sintered located between said other ends of said track means; igniting means for igniting said material located between said track means and at said end of said sintering zone to ignite the material on pallet means entering said sintering zone; means for blowing a stream of air transverse to said track means through said pallet means and material thereon in said cooling and sintering zones; separating means at said one end of said one track means for separating sinter from the sintered material; means for placing said sinter successively on pallet means on the other track means when said pallet means enter said cooling zone so that the sinter is cooled; and means for removing the cooled sinter from said pallet means at the end of said cooling zone.

6. In a sintering machine, in combination, a plurality of pallet means each pallet means having supporting roller means and reversing roller means; a pair of substantially parallel track means for supporting said pallet means and on said supporting roller means, one of said track means having a major portion extending from one end thereof and constituting a sintering zone and the other track means having a major portion extending from one end thereof and constituting a cooling zone, said cooling and sintering zones having ends spaced from the other ends of said track means; a pair of moving and reversing means at the ends of said track means for pushing pallet means in end to end relationship along said track means, and for reversing each pallet means at the ends of said track means, said reversing means including sprocket means engaging said reversing roller means and guide tracks for guiding said supporting roller means; charging and feeding means for charging said pallet means with material to be sintered located between said other ends of said track means; igniting means for igniting said material located between said track means and at said end of said sintering zone to ignite the material on pallet means entering said sintering zone; means for blowing a stream of air transverse to said track means through said pallet means and material thereon in said cooling and sintering zones; separating means at said one end of said one track means for separating sinter from the sintered material; means for placing said sinter successively on pallet means on the other track means when said pallet means enter said cooling zone so that the sinter is cooled; and means at said other end of said other track means for removing the cooled sinter from said pallet means.

7. In a sintering machine, in combination, a plurality of pallet means; a pair of substantially parallel track means for supporting said pallet means, one of said track means having a major portion extending from one end thereof and constituting a sintering zone and the other track means having a major portion extending from one end thereof and constituting a cooling zone, said cooling and sintering zones having ends spaced from the other ends of said track means, said one track being located above said other track and in a common vertical plane; a pair of moving and reversing means at the ends of said track means for pushing pallet means in end to end relationship along said track means, and for reversing each pallet means at the ends of said track means; charging means for charging said pallet means with material to be sintered located between said other ends of said track means igniting means for igniting said material located between said track means and at said end of said sintering zone to ignite the material on pallet means entering said sintering zone; means for blowing a stream of air transverse to said track means through said pallet means and material thereon in said sintering zone and cooling zone; separating means at said one end of said one track means for separating sinter from the sintered material; means for placing said sinter successively on pallet means on the other track means when said pallet means enter said cooling zone so that the sinter is cooled; and means for removing the cooled sinter from said pallet means at the end of said cooling zone.

8. In a sintering machine, in combination, a plurality of pallet means; a pair of substantially parallel track means for supporting said pallet means, one of said track means having a major portion extending from one end thereof and constituting a sintering zone and the other track means having a major portion extending from one end thereof and constituting a cooling zone, said cooling arid sintering zones having ends spaced from the other ends of said track means, said tracks being located in a common horizontal plane; a pair of moving means at the ends of said track means for pushing pallet means in end to end relationship along said track means; transfer means for transferring each pallet means from the end of each track means to the corre spending end of the other track means, for separating each transferred pallet means from the pallet means directly trailing the same, and for inclining each pallet means during the transfer for discharge of material therefrom; charging and feeding means for charging said pallet means with material to be sintered located between said other ends of said track means; igniting means for igniting said material located between said track means and at said end of said sintering zone to ignite the material on pallet means entering said sintering zone; means for blowing a stream of air transverse to said track means through said pallet means and material thereon in said cooling and sintering zones; separating means at said one end of said one track means for separating sinter from the sintered material; means for placing discharged sinter successively on pallet means on the other track means when said pallet means enter said cooling zone so that the sinter is cooled; and means for removing the cooled discharged sinter from said pallet means at the end of said cooling zone.

References Cited in the tile of this patent UNITED STATES PATENTS 916,393 Dwight et a1. Mar. 23, 1909 1,568,791 Aiken Jan. 5, 1926 2,090,363 Wendeborn Aug. 17, 1937 2,862,308 Meredith Dec. 2, 1958 2,987,307 Homan June 6, 1961 FOREIGN PATENTS 156,827 Switzerland Nov. 1, 1932 618,184 Germany Sept. 5, 1935

Claims

1. IN A SINTERING MACHINE, IN COMBINATION, A PLURALITY OF PALLET MEANS; A SINTERING ZONE; A COOLING ZONE; CONTINUOUS PALLET CONVEYOR MEANS FOR CONVEYING SAID PALLET MEANS SAID CONVEYOR MEANS INCLUDING TWO REVERSAL SECTIONS AND TWO ELONGATED SECTIONS CONNECTING SAID REVERSAL SECTIONS, SAID ELONGATED SECTIONS BEING LOCATED IN SAID ZONES, REPSECTIVELY, SAID CONVEYOR MEANS BEING ADAPTED TO MOVE SAID PALLET MEANS IN A CLOSED PATH FROM ONE OF SAID REVERSAL SECTIONS OVER ONE OF SAID ELONGATED SECTIONS TO THE OTHER ONE OF SAID REVERSAL SECTIONS AND THEREFROM TO SAID ONE REVERSAL SECTION OVER THE OTHER ONE OF SAID ELONGATED SECTION, WHEREBY SAID PALLET MEANS ARE PASSED THROUGH SAID ZONES WHILE BEING MOVED OVER EACH OF SAID ELONGATED CONVEYOR MEANS SECTIONS, CHARGING MEANS FOR SUCCESSIVELY CHARBING SAID PALLET MEANS WITH MATERIAL TO BE SINTERED AND IGNITING MEANS FOR IGNITING SAID MATERIAL LOCATED RELATIVE TO SAID CONVEYOR MEANS TO IGNITE THE MATERIAL WHEN SAID PALLET MEANS ENTER SAID SINTERING ZONE; MEANS FOR BLOWING A STREAM OF AIR THROUGH SAID PALLET MEANS IN SAID SINTERING ZONE TO INCREASE COMBUSTION: CRUSHING MEANS AT THE END OF SAID SINTERING ZONE FOR CRUSHING THE SINTERED MATERIAL INTO CRUSHED MATTER CONTAINING SINTER; SEPARATING MEANS FOR SEPARATING SINTER FROM OTHER CRUSHED MATTER; FOR PLACING SAID SINTER SUCCESSIVELY ON SAID PALLET MEANS WHEN THE SAME ENTER SAID COOLING ZONE SO THAT SAID SINTER IS COOLED; AND MEANS FOR REMOVING THE COOLED SINTER WHEN SAID PALLET MEANS LEAVE SAID COOLING ZONE.