US3059912A - Self-sealing sintering machine and sinter cooler - Google Patents

Description

R. S. COTTON Oct. 23, I962 SELF SEALING SINTERING MACHINE AND SINTER COOLER 3 Sheets-Sheet 1 Filed April 15. 1960 INVENTOR. 05527 $.Cerw1/ (97- TUBA/5.7.

Oct. 23, 1962 R. s. COTTQN 3,059,912

SELF- SEALING SINTERING MACHINE AND SINTER COOLER Filed April 15, 1960 3 Sheets-Sheet 2 TmrLINQ WHEEL,

IN V EN TOR. 1/ P aser S. (To 7- re R. COTTON Oct. 23, 19 62 SELF-SEALING SINTERING MACHINE AND SINTER COOLER n Filed April 15. 1960 3 Sheets-Sheet 3 JNVENTOR.

P6554875. Cow-7'0 United States Patent M 3,tl59,912 SELF-SEALIIIG SHNTERING MAtIHINE AND SINTER CQOLER Robert S. Cotton, Pittsburgh, Pa., assignor to Koppers Company, line, a corporation of Delaware Filed Apr. 15, 1960, Ser. No. 22,552 Claims. (Cl. 266-21) This invention relates in general to improvements in sintering apparatus, and more particularly, to improved means for preventing leakage between the moving pallets and the wind boxes over which they pass in sinter apparatus of the continuous type as extensively used for sintering and cooling on sinter machine and sinter coolers of metallic ores, concentrates, blast furnace flue dust, and the like, wherein a series of pallets are moved in abutting relation in an endless train along a pair of tracks in an upper run over wind boxes for flow of combustion air through the material on the pallets to effect the sintering of the material, and likewise, in an endless train along a pair of tracks in a lower run for return to the upper run, with movement of the pallets in an arcuate path from one run to the other at each end of the runs.

In sinter apparatus of this type, it is essential to seal the joint between the moving loaded pallets and the wind boxes in the upper run of sinter machines and sinter coolers to insure that all the air intended for passage through the material on the pallets. passes uniformly through the bed of material on the pallets. The air may be forced upwardly by a forced up draft in sinter coolers, first through the wind boxes, and thence, to and through the bed on the pallets, or may be drawn downwardly by induced downdraft in sinter machines, first through the bed on the pallets, and thence, to and through the wind boxes.

In either case, the joint where the pallets slide along the wind boxes must be sealed to avoid short circuiting of the bed by the air. This is done conventionally by means of a sliding seal contact between the pallets and the wind boxes which results in wear. To minimize thi wear, it has been found best, in actual practice: to suspend the pallets above the wind boxes by means of wheels at the sides of the pallets which run on rails, so that the weight of the loaded pallets is carried entirely by the rails, rather than partly or mainly, by the wind boxes, as the pallets move along the same in abutting relation; and for sealing, the wind boxes are provided with renewable wear bars along their tops and the pallets are provided with selfadjusting seal bar along the sides of the pallets and attached thereto in position for sliding contact with the tops of the Wear bars, for sealing the joint between the moving pallets and the wind boxes. These seal bars are fixed to the pallets by a pin and slot connection for movement along the wind boxes with the pallets, in a manner to be freely movable in a vertical direction in a longitudinal groove or recess while resting at their bottoms on the tops of the wear bars. The bars are contained in the longitudinal grooves or recesses along the bottoms of the sides of the pallets so that the sides of the seal bars are always in practical contact with the pallets, to maintain between the latter and the wear bars, a substantially airtight joint, regardless of variations in the vertical positions or displacement of the pallets with respect to the wear bars on the wind boxes. In practice, these longitudinal grooves or recesses are downwardly open ones as viewed in the upper run, and extend uninterruptedly from front to back of the pallets and are open at the front and rear ends of the pallets to permit the use of simple, rectangular bars or plates which can fit into the recess or groove with only suflicient clearance to permit of free gravity movement of the seal bar therein under the influence of only their own weight in order to further avoid wear and friction while still effectively sealing the joint. To permit this vertical move- 3,@59,9l2 Patented Get. 23, 1952 ment while preventing endwise movement in the seal bar recesses of the sealing bars relative to the pallet, the bars are provided with spaced apart vertical slots and intersecting pins which are secured in the pallet but project through the sides of the pin slots. Hence, under the various conditions of operation of the sinter strand, any variation in level of the wear bars or pallets which may occur in the upper strand that might impair the integrity of the joint as a seal, as the loaded pallets move along over the wind boxes from the feed end to the discharge end of the machine, is compensated for by the seal bars, since the latter under the influence of gravity, float relative to the pin in the slot while riding on the wear bar and drop under gravity to the face of the wear bar, in event of a depression in the wear bar or a rise of the pallet, and rise relative to the pallet, in the event of an elevation in the wear bar or a fall in level of the pallet.

Thus, the seal bar, in operation on the pallet, is a freely floating seal member which effects the closure of the joint by a comparatively insignificant mass or weight compared with the weight of the pallet itself, and which is self-adjustable to maintain the joint closed solely by the gravital force of the free fall of the bar under the influence of its own weight.

During the movement of the pallets in an arcuate path around the discharge end of the machine, the abutting pallets separate in the form of a V as they discharge the sintered material, and as they enter and move along the lower run, they are inverted. Thus, the seal bar grooves or recesses, which were downwardly open in the upper run, become upwardly open in the lower run and the seal bars drop down by gravity in the seal bar groove or recess until the upper end of the pin slot in the floating seal bar rests on the pin therein, leaving the rest of the slot open below the pin. As a consequence, in time, the dirt or other foreign material, such as sinter, becomes wedged in the spaces between the sides of the seal bar and the vertical walls of the groove or recess for the bar, and also lodges in the pin slot beneath the pin in the lower run. When this occurs, the bar becomes stuck or hung in this position when in the recess or groove when the pallet is returned upright in the upper run, so that the bar cannot return of its own weight to the sealing contact with the wear bars on the wind boxes, permitting leakage of air through this joint, and thus short-circuiting the air for sintering around the material on the pallets, resulting in inefficient sintering of the material.

To eliminate this, springs have been used between the bar and the pallet, as in Schofield US. Patent No. 2,848,214, to urge the bar upwardly, in the inverted position of the pallets in the lower run, so that the lower end of the pin slot in the bar, when in the lower run, engages the pin in the slot. While this serves to prevent accumulation of sinter and dust beneath the pin in the slot of the seal bar when in the lower run, and thus eliminates much of the sticking of the bars in their unsealing location on the pallets when in the upper run, nevertheless, there still are occasions when such bars still become stuck, with the result of ineflicient sintering in the upper run, due to shortage combustion air for the sinter bed as a result of ineffective sealing. As a consequence, to insure proper contact of the seal bars with the wear bars in the upper run, the stickers must be removed to attain the intended proper sintering or cooling operation, either by manually cleaning out the stickers from the bars while in the sealing grooves or recesses on the pallet, or by providing special means on the sintering machine and sinter cooler to pull the seal bar down, to avoid damage to the apparatus in case of a hang-up bar which resists freeing by manual operation.

The present invention provides a simple and more effective means for eliminating these difficulties in a manner a which prevents the entrance of such dust and sinter into the grooves or recesses where such stickers have occurred, and thus, assures a more effective gravity sealing of the wind boxes in the upper run, with a minimum of maintenance or attention.

Accordingly, the invention provides a sintering machine and sinter cooler of the endless type described with pallets having caps or end plates covering the vertical ends of the seal bar grooves on each side of the pallets at each of the front and rear ends of the pallet frame, to prevent ingress of sinter dust through said vertical ends into the seal bar grooves when the abutting pallets separate to form a V opening between adjacent pallets at the sinter discharge end of the machine where they move down in an arcuate path to the lower run of the machine.

Sintering machines and sinter coolers with such vertical end plates or caps as aforesaid operate with a minimum of stickers which heretofore have resulted in defects in sealing of the joints between their wind boxes and the pallets in the upper run, when sealed by floating gravity seal bars, that seal solely under the influence of their own weight as above-described, with and without further means, such as springs or levers, for urging the bars into sealing relation.

The invention also provides a pallet sealed sinter system in which seal bars, themselves, are used to seal the seal bar groove or recess throughout its length in the inverted position of the pallets, when the pallet seal bars drop down by gravity in their grooves, during return of the pallets to the feed end of the sintering machine or sinter cooler along the lower run. Accordingly, the present invention contemplates a pallet system of sintering and cooling as aforesaid with seal bars having dust sealing par-ts located thereon below the pin slots at a region lower than the bottoms of the grooves in the upper run, for free floating movement of the seal bars in sliding contact with the wear bars in the upper run and at a distance less than the height of the pin slot for closing contact with the bottoms of the grooves, or other pallet parts, to close ofi the space between the seal bars and the walls of the seal bar grooves against ingress of dust and sinter, when the seal bars drop down in the grooves by gravity Where the pallets become inverted in the lower run.

The conjoint use of the end caps and these dust sealing parts in conjunction with the pallets, prevents any sinter dust particles from getting into the seal bar grooves or recess in the arcuate portions of the pallet train at the feed and discharge ends of the machine, and in the lower run, and yet permits the seal bars to rise and fall freely in their grooves for sealing contact with the wear bar, when the pallets return to the upper strand.

The invention is not limited in all its aspects to the use of the end caps in conjunction with the dust sealing parts on the seal bars, since much of the advantage of the invention may be attained with the use of the novel end caps without conjoint use of the dust sealing parts on the seal bars, since the end caps may be employed, in such case, in conjunction with the combined spring and floating seal bar system of the aforesaid Schofield Patent No. 2,848,214; and much of the advantage of the invention may be attained by the employment of the dust sealing parts on the seal bar without conjoint use of the end caps, as may be the case where plate extensions are employed on the front or rear of the pallets in a manner to overlap or telescope with the rear or front of an adjacent pallet where the pallets enter the bend at the discharge end of the machine, to bridge the V-space formed between the grates of adjoining pallets in order to prevent spillage and discharge of sinter between the pallets as they turn to the lower strand. Hence, the invention is not limited in all its aspects to the specific use of the end plates or caps, together with the dust sealing parts on the seal bars, in all sinter installations, although they are so embodied together and described hereinafter as the best mode of operation for purpose of illustration.

Referring to the drawings:

FIGURE 1 is a diagrammatic side elevational view of a conventional endless strand continuous sinter apparatus, which may be a sintering machine or sinter cooler, embodying the invention and illustrating the separation of the pallets with the formation of a V-shaped space between them as they pass around the arcuate bends at the discharge and feed ends of the machine.

FIGURE 2 is an enlarged fragmentary vertical crosssectional view of the upper run of the apparatus, taken on the line III1 of FIGURE 1.

FIGURES 3 to 6 inclusive are similar views taken through the discharge end of the machine.

FIGURE 7 is a vertical cross-sectional view of one side of the pallet.

FIGURE 8 is a vertical sectional view on the line VIII-VIII of FIGURE 7 showing the front end of one side of the pallet with the seal bar in the seal bar groove or recess in the side of the pallet and with the novel end plate for upwardly closing the vertical end of the channel at the front of the pallet.

FIGURE 9 is an isometric view of the novel sealing bar for self-sealing the pallets.

FIGURE 10 is an enlarged view on a reduced scale showing a pallet and its seal bars in their inverted position.

The invention can be embodied in any one of a number of types of endless pallet sinter apparatus and, by way of example, is disclosed as embodied in a continuous sintering machine, such as the one disclosed in Wilfred C. Schofield Patent No. 2,848,214, dated August 19, 1958. The construction and operation of this type of sintering machine are Well known in the art, and a brief description thereof will suflice. The sintering machine as shown in FIGURE 1, comprises a suitable frame carrying an endless t-rack having an upper horizontal run 2 and a lower sloping run 3 upon which travel the upper run and lower run of a train of pallets 4. At the feed end 7 of the machine, the pallets are raised to their upper run position 2 by known sprocket means from the lower run 3 of the track about the return bend to the upper run. The portions of the tracks 2 and 3 at the ends of the apparatus serve as guides rather than tracks as seen in FIGURES 2 to 6. Each pallet 4 comprises a frame 8 which carries a suitable grate 5, FIGURE 7, and the pallets on the upper run of the track are in front and rear endwise contact providing a continuous traveling grate structure, the pallets being mounted with wheels 9 for travel on the tracks 2, 3, as is known. A charging chute is positioned at the feed end 7 of the machine to provide the pallets with a bed of material to be sintered, the bed being supported by the grate structure and traveling therewith. The pallets pass along the upper run 2 from the charging chute to an igniter where the top of the bed of material is ignited. During the remainder of the travel of the pallets along the upper run, they pass over wind boxes 15 These boxes are connected by conduits to a manifold,

which in turn is connected to the intake of a suction fan,

the outlet of the fan being connected to a conduit which goes to a stack which can discharge into the atmosphere.

During the upper run travel of the pallets over wind boxes 10, air in large volrune is drawn downward by induced down-draft through the bed of material on the grates 5, causing down-draft combustion therein from the top to the bottom of the bed so that the bed of material has been completely sintered by the time it reaches the discharge end 11 of the machine, as is known in the art. As the pallets pass from wind boxes 10 around the bend at the discharge end .11 to the lower end of track 3, the sinter on these pallets is discharged onto an inclined crash deck which directs the sinter cake to a crusher where it is broken up to a predetermined size by crusher rolls and then to a screen formed of grizzly bars. The fines and small pieces of sinter pass into a bin positioned below the screen and provided with a discharge spout, normally closed by a valve of suitable size. A hood is usually positioned above the screen and extends over a portion of the upper run of pallets at the discharge end 11 of the upper run to convey air carrying dust given off from the sinter at the discharge end 11 of the machine, back into the beds on the grates 5, FIGURE 7. The air for sintering passes through the portions of the sinter bed as it moves toward the discharge end 11, and thence, through the grate 5 in the pallet frame *8 into the tops of the wind boxes 10, whence the combustion air is withdrawn by the suction fan to the stack. The apparatus so far described is conventional in the sintering art and it is to be understood that the inventive structure described hereinafter is not limited in its application to specific endless track sintering machine embodiment as disclosed but can be readily incorporated in any one of a number of other well-known types of endless track sintering machines and sinter coolers,

Referring to FIGURES 2 to 6 of the drawing, it can be seen that the whole length of the tops of the row of wind boxes 10 is fitted, on both sides of the upper run, with a rectangular wearing bar r12. These wearing bars 12 are mounted on wind box supports 13 and constitute the fixed member of the sliding joint which is maintained between the pallets 4 and the wind boxes 19 as the pallets pass over the openings of such boxes, and at the discharge end 11 of the machine, the wear bars are continued beyond the wind boxes on wear bar sup ports 14.

In the under surfaces of the pallets 4 from front 15 to rear 16 of the pallets, FIGURES 8 and 9, are formed parallel spaced longitudinal seal bar grooves or recesses 17 into which fit the gravity seal bars 1 8. In their simplest embodiment, these seal bars are comprised of rectangular plates or bars of the same length as the pallet and fit into the aforementioned recesses 17 with only suflicient clearance to permit of free vertical movement therein. To prevent the seal bars 118 from endwise movement in the pallets in the direction of its front and rear, they are held by rods or pins 19 projecting transversely through the walls 20 of the grooves or recesses 17 in the pallets and through vertically elongated slots 21 in the bars 18, FIGURES 8 and 9. A cotter pin 22, FIGURE 7, passes through each rod 19, and serves to hold each rod in position. The grooves or recesses 17 are open at the front 15 and rear 16, as well as the bottoms 32 of the frames 8 of the pallets 4-.

Seal bars 18, such as above described, are preferably used which depend upon the influence of their own weight only, to effect a gravity seal between themselves and the wear bars 12 fixed to the tops of the wind box supports 14 in the upper run, the sealing pressure being merely that exerted by the weight of the bar 18. Hence, when the pallets are inverted in the lower run of the track 3, as shown in FIGURE 6, the seal bars 18 readily dropped by gravity to have the extreme ends 23 of the elongated pin slots 21 that are nearest the sealing edges 24 of the seal bars 18, engage the pins 19 in the lower run 3, and loose sinter sometimes wedges between the pins 19 and the seal bar 18 at the end 25 of the pin slot 21 that is remote from said sealing edge 24, when the pallets 4- are in such inverted position, thereby preventing the seal bars 1 8, when returning to the upper run 2, from falling downward by gravity into sealing position or contact of their sealing edge 24 with their wear bars 12 as the pallets pass over the entrance end of the wear bars 12 at the feed end 7 of the machine when the pallets enter the upper run 2 to move over the top openings in the wind boxes 1G in the upper run 2.

To overcome this, continuous pressure means in the form of springs have been interposed between the top surface 26 of such seal bar 1 8 and the bottom surface 27 of each groove or recess 17, FIGURE 8, as seen in the upper run 2 of the pallets 4, according to the aforesaid Schofield Patent No. 2,848,214. These springs constantly urge the seal bars 18 outwardly and move the entire weight of these gravity sealing bars away from the bottom surface 27, when inverted in the lower run 3, as seen in FIGURE 6, to bring the ends 25 of the slots 21 against pins 19 so as to prevent wedging of the bars as heretofore, by loose sinter between the pins 19 and the end 25 of the slot 21 remote from the sealing edge 24 of the bars 18 when the pallets 4 are in upside down position (FIGURE 6). In the inverted position of the pallets, the springs leave an open space between the pins 19 and the end 23 of the slot 21 closest to the sealing edge 24 of the bar 18, instead of being suspended by gravity from the pins 19 at that end 23 of the slot 21, as seen in FIGURE 6, which would leave an open space between the pins 19 and the end 25 of the slot 21 remote from the sealing edge 24 of the bars .18. Hence, the bars 18 actually contact the wearing bars 12 as the pallets turn at the feed end 7 to enter the upper run 2. Any sinter or stickers are then lodged between the pins 19 and the end 23 of the slots 21, which is closer to the sealing edge 24 of the bar 18, rather than between the pin 19 and the end 25 of the slot 21 remote from the sealing edge 24, as heretofore occurred with solely gravity sealing. As a consequence, with the Schofield arrangement, the cam action of the wear bar 12 acts on the seal bar 18 to exert a crunching or grinding force on the sticker against the pin 19 and the weight of the pallet 4, so that the sticker is thereby crumbled, allowing the sealing bar 1? to resume its normal relation in the upper run, with the pin 19 at the normal intermediate level, as shown in FIGURES 2 and 3.

In this manner, the springs, when used with the sealing Weight of these bars 18, as normally used in these gravity sealing bars, eliminates the defect in sealing, due to stickers in their slots as heretofore obtained with the use of bars to seal by gravity solely under the influence of their own weight.

According to the present invention, to prevent sinter and other dust from entering between the seal bar 18 and the walls 20 of the recess or groove 17, at the ends 15 and 16 of the pallets, as may occur at the bends of the machine at the discharge end 11 and the feed end 7, each of the pallets is provided at their front ends 15 and at their rear ends 16 with upwardly extending end plates or caps 28 to close the ends of the sealing bar grooves or reces against ingress of dust or sinter. These plates are welded in place by weldments as indicated at 39. These plates 28 extend upwardly from the bottoms 32 of the frames 8 to the top 27 of the grooves or re cesses '17 and overlap the wide walls 2% of these grooves to exclude dust from entering along these walls 26 or along the top 27.

As shown in FIGURES 2 to 6 inclusive, each wear bar has an inclined top surface 39, and the seal bars 18 terminate in a corresponding inclined surface 31, as is conventional in this art.

In accordance with another feature of this invention, the seal bars 18 are provided, as shown in FIGURES 8 and 9, with sealing parts 3 3, 34 to close off the space between the sides of the seal bars 18 and the side walls 20 of the seal bar grooves or recesses 17. These parts 33, 34 are positioned on the bars 1 8, as shown in FIG- URE 8, to be disposed a spaced distance below the bottoms 32 of the frame 8 at the lower extremities 32 of the Walls 2t (FIGURES 2 to 6) a distance sufficient, slightly less than the height of the free space left in the pin slot 21 when the end 25 of the slot 21 is resting on the pin 19 whenever the bar 18 is free of the wear bar 12 in the upright position of the pallets, to permit the bar to rise and fall :freely, by the force of its own weight, when riding the wear bar 12, but so as to overlap in contact with the bottom 32 of the pallet frame 8 in the region of the two opposite side walls 20 of the sealing groove or recess 17, when the pallets are inverted on the lower run 3, as shown in FIGURE 6.

For simplicity in manufacture and assembly, as well as economy, these parts 33, 34 are formed in one piece with the sealing edge 24, 31 of the seal bars 18, by welding or casting a transversely extending member in the form of the cross or capital 35 of a T-bar to the outer extremity of the portion of the sealing bar 18 that floats in the groove or recess 17. Thus, the upper surfaces of the projecting portions of the cross member constitutes the sealing pants 33, 34 for sealing the spaces between the sides of bar 18 and the walls 20 of their grooves against ingress of sinter dust in the lower run 3 of the machine, and the bottom inclined surface 31 constitutes the movable sealing member surface for contact with fixed sealing member 12. The bars 18 terminate just short of the end caps 23, but the cross or capi al 35 projects under the caps 28, as seen in FIGURE 8.

The invention is not limited in all its aspects to the use of such T-shaped sealing bar 18, since much of the advantage of the invention may be attained by utilizing other sealing parts 33, 34 on the bar 18, between the bearing surface 31 and lower extremity 25 of the pin slot 21, FIGURES 6 to 9, as the means to close off the space between the sides of the bar 18 and the walls 20 of the recess or groove 17, throughout the length of the same from front to back 16 of the pallet frame 8, when the bar 18 drops by gravity in the inverted position of the pallets 4 in the lower run 3.

The operation of the apparatus as a sinter machine or sinter cooler with the novel self-sealing means thereon will be readily apparent from the aforesaid description thereof. Hence, it suffices to point out that as the pallets move around the bends at the discharge end 11 and feed end 7, the abutting pallets 4 tend to form a V-space between the rear 16 of a discharged pallet 4 and the front 15 of the next pallet that is discharging sinter to the crash deck. Any dust or sinter fines that might enter through the open ends of the recesses 17, as heretotore was the case, is now prevented from so doing by the caps or end plates 28. As the pallets 4 enter the lower run 3, and move along the same from the discharge end 11, toward the feed end 7, the sealing parts 33, 34 overlap the bottoms of the walls 20 of the recesses or grooves, as shown in FIGURE 6, throughout the lengths of the pallets 4 and the bars 18, from front 15 to back 16.

As the pallets enter the return bend, and reenter the feed end 7 through the return bend, the sealing bar operates in the same manner in the portions thereof corresponding to the portions of the bend at the discharge end, as shown and described above as to FIGURES 6 to 2.

Where it is desired to use springs as in the above-noted Schofield Patent No. 2,848,214, then the sealing parts 33, 34 are omitted and only end caps 28 are used in the pallets 4 in conjunction with the spring-urged sealing bar.

Where telescopic overlapping side plates or bottom extensions are used between the abutting pallets to avoid spillage between the same at the discharge bend, then the sealing caps 28 are omitted and only the sealing parts 33, 34 are used in conjunction with the telescopic spillage prevention means on the pallets 4.

The invention as hereinabove set forth is embodied in a particular form of construction but may be variously embodied within the scope of the claims hereinafter made.

I claim:

1. A continuous sintering apparatus comprising: an endless track having an upper and a lower run; a Wind box having an upper opening along the upper run of the track; an endless train of pallets ridable upright across said wind box opening in the upper run and ridable inverted along the lower run of said track; a sealing wear bar fixed relative to said wind box opening; gravity seating seal bars floatingly suspended by a pin and slot connection in a downwardly open groove extending from front to back along one side of each of said pallets, said seal bars being sufliciently heavy to seal on the sealing wear bars; end plates extending upwardly along the ends of the grooves throughout the height of the same at the front and back of the pallets to preclude ingress of dust into the grooves through said ends; and sealing parts positioned on the seal bars intermediate said slots and the sealing edge of said seal bars to move into a sealing relation that prevents entrance of dust and sinter between the seal bars and the side walls of the grooves at the downwardly open portion of the grooves when the pallets are inverted in the lower run, to insure sealing by gravity seating of the seal bars on the wearing bars when said pallets move upright past said wind box opening in the upper run.

2. A continuous sintering apparatus comprising: an endless track having an upper and a lower run; a wind box having an upper opening along the upper run of the track; an endless train of pallets ridable upright across said wind box opening in the upper run and ridable inverted along the lower run of said track; a sealing wear bar fixed relative to said wind box opening; gravity seating seal bars floatingly suspended by a pin and slot connection in a downwardly open groove extending from front to back along one side of each of said pallets, said seal bars being sufliciently heavy to seal on the sealing wear bars; and end plates extending upwardly along the ends of the grooves throughout the height of the same at the front and back of the pallets to preclude ingress of dust into the grooves through said ends, to insure sealing by gravity seating of the seal bars on the wearing bars when said pallets move upright past said wind box opening in the upper run.

3. A continuous sintering apparatus, comprising: an endless track having an upper and a lower run; a wind box having an upper opening along the upper run of the track; an endless train of pallets ridable upright across said wind box opening in the upper run and ridable inverted along the lower run of said track; a sealing wear bar fixed relative to said wind box opening; gravity seating seal bars floatingly suspended by a pin and slot connection in a downwardly open groove extending from front to back along one side of each of said pallets, said seal bars being sufiiciently heavy to seal on the sealing wear bars; sealing parts positioned on the seal bars in- .termediate said slots and the sealing edge of said seal bars to move into a sealing relation that prevents entrance of dust and sinter between the seal bars and the side walls of the grooves at the downwardly open portion of the grooves when the pallets are inverted in the lower run, to insure sealing by gravity seating of the seal bars on the wearing bars when said pallets move upright past said wind box opening in the upper run, and in which the seal bars each comprise a bar of T-shape in cross-section with the cross of the T adapted to overlap and seal the joint between the vertical leg of the T and the side walls of the grooves.

4. A self-sealing sinter pallet, comprising: a grate frame with means at opposite sides thereof for suspending the pallet for movement along fixed sealing wear bars above wind box means for the pallet; gravity seating seal bars tioatingly suspended by a pin and slot connection in a downwardly open groove extending from front to back along each side of said pallet, said seal bars being sufficiently heavy to seal on the sealing wear bars; end plates extending upwardly along the ends of the grooves throughout the height of the same at the front and back of the pallet to preclude ingress of dust into the grooves through said ends; and sealing parts positioned on the seal bars intermediate said slots and the sealing edge of said seal bars to move into a sealing relation that prevents entrance of dust and sinter between the seal bars and the side walls of the grooves at the downwardly open portion of the grooves when the pallet is inverted, to insure sealing by gravity seating of the seal bars on the Wearing bars When said pallet moves upright past said wind box means.

5. A self-sealing sinter pallet, comprising: a grate frame with means at opposite sides thereof for suspending the pallets for movement above and along fixed sealing Wear bars above Wind box means for the pallet; gravity seating seal bars floatingly suspended by a pin and slot connection in a downwardly open groove extending from front to back along each side of said pallet, said seal bars being sufficiently heavy to seal on the sealing Wear bars; and end plates extending upwardly along the ends of the grooves throughout the height of the same at the front and back of the pallet to preclude ingress of dust into the 10 grooves through said ends, to insure sealing by gravity seating of the seal bars on the wearing bars when said pallet moves upright past said wind box means.

References Cited in the file of this patent UNITED STATES PATENTS 2,485,422 Urban Oct. "18, 1949 2,789,809 Grabau et a1 Apr. 23, 1957 FOREIGN PATENTS 521,932 Canada Feb. 21, 1956 812,760 Great Britain Apr. 29, 1959

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