US2743534A - Apparatus for cooling sinter - Google Patents

Description

May 1, 1956 M. L. COVER APPARATUS FOR COOLING SINTER 2 SheetsSheet 1 Filed Sept. 29, 1952 n fllw INVENTOR.

MART/N Z. fiovfk BY ""'"l I I 2 A7 May 1, 1956 M. L. COVER ,534

- APPARATUS FOR COOLING SINTER Fil ed Sept. 29, 1352 2 Sheets-Sheet 2 INVENTOR.

6 MflAT/A/ z. 601 0? ATTOR/VfYS United States Patent APPARATUS FOR COOLING SINTER Martin L. Cover, Allen Park, Mich.

Application September 29, 1952, Serial No. 312,017

9 Claims. (Cl. 34-174) This invention relates generally to apparatus for sintering materials for use in blast furnaces.

It is well known that to provide a proper blast furnace charge or burden fine materials such as iron ore, flue dust, necessary fuel in the form of carbon, fine coke and so forth and fine sinter returns are mixed, charged onto pallets of a sintering machine, ignited, and burned by a blast of air drawn through by suction. Then the usually still hot sinter is discharged from the pallet, cooled, and then fed to a blast furnace at the proper time.

Sintering machines of the Dwight and Lloyd endless track type are well known, and in these machines, one of which is shown in the Babb Patent 2,441,383, issued May 11, 1948, plurality of pallets are arranged in a continuously moving machine with wind boxes or suction boxes provided underneath the pallets during the loading cycle. A suction fan produces a vacuum of from 20 to 30 inches of water in the wind boxes and pulls air down through the mixture forming the sinter bed. The sinter bed is supported by grate bars, and an ignition furnace extending across the sinter bed ignites the material at the top as it passes a point adjacent the loading station.

The burning of the sinter progresses from top down to the grates and is usually so arranged that it reaches the grates at about the time that the sinter is ready for discharge. This means that a portion of the sinter adjacent the grates may have a temperature of 1800 to 2000 F. whereas the portion of the sinter adjacent the top of the bed may be from around room temperature to 200 F. There is then the problem of cooling the sinter after it is discharged from the sintering beds.

Since the sinter is to be part of the burden of a blast furnace, it is essential that it have certain characteristics in order to insure uniform and most efiicient operation of the blast furnace. One of the characteristics required is a fairly uniform size and suflicient structural strength to support the overburden. The usual size desired is around one inch diameter of particles with as little fine material as possible.

A sinter which leaves a sinter bed in good condition from the point of view of size and strength may be entirely destroyed by the method of cooling. The elfect of sudden cooling of the hot sinter with water, for example, is a destruction of the pieces which are apt to be frangible following the sintering operation. This destruction can also take place by too rapid air cooling as when extra wind boxes are provided in the sintering machine. On

the other hand, if the sinter is merely dumped in a pile I 2,743,534 Patented May 1, 1956 ice ity to prevent undue piling up of the same and to have a continuous flow of the material with a final deposit from the rubber loading belt to the blast furnace stockhouse.

Briefly, the invention includes placing the sinter on a slow moving pan type conveyor where it is exposed to natural circulation of air for a period of 10 to 15 minutes. This effectively cools the surface of the sinter so that it can be accumulated, but the interior heat would again heat the sinter to a fairly high temperature when it is placed in a pile. Consequently, the sinter is then dumped from the slow moving conveyor to a large stationary bin of around 1,000 ton capacity and air is blown up through the sinter. 1 Since the storage period in the bin may be several hours, this air will cool the sinter to the safe temperature at which it can be handled for burdening the blast furnace or removal to the stock pile.

The sinter is fed from the bin by means of a rotating table feeder onto a rubber conveyor and conveyed to bins at the blast furnace. The invention contemplates a novel construction of a storage bin which requires only a little power to operate and which has few moving parts to wear.

Other objects and features of the invention having to do with details of construction will be apparent in the following description and claims.

Drawings accompany this application, and the various views thereof may be briefly described as:

Figure 1, a vertical section and diagrammatic lay-out of the various parts of the cooling apparatus.

Figure 2, a view of a modified cooling bin which may be associated directly with a sinter machine.

Figure 3, a plan view of the modified cooler.

Figure 4, a sectional view of the modified cooler showing greater detail of construction.

Figure 5, a sectional view on line 5-5 of Figure 4.

Referring to the drawing, in Figure 1 a sintering machine is shown at S having the pallet conveyor 10 passing over wind boxes 12 near the discharge end of the machine. A hot fines screen 14 sifts the fine material out of the sinter as it leaves the sintering machine and passes it to a hot fines bin 16 where it is cooled and returned by a conveyor 18 to the origin of the sinter mix.

The main bulk of the sinter as it is discharged from the sintering machine will deposit onto a pan conveyor C having a series of pallets 20 which are continuous and which pass continuously around rollers 22 at opposite ends of the conveyor. This conveyor is preferably about feet long and will be operated at the rate of about 10 feet per minute. The sint-er will leave the sintering machine with varymg temperatures, the top of the sinter on each pallet being from 200 to 400 F. while the portion near the grate may be as high as 1000" F. After passing over the conveyor C the temperature should reduce normally to about 800 F. and the material will then be dumped into the cooling bin B.

A baffle 30 is provided at the top of the bin to distribute the material evenly as it dumps into the bin. The bin has a cylindrical portion 32, below which is an outwardly extending conical portion 34. The diameter of the bin then reduces in another conical portion 36 to a bottom cylindrical portion 38. The bin B would probably be roughly 50 feet in height and 25 feet in diameter in the top cylindrical portion, the conical portions being slightly wider at their point of greatest diameter. The capacity of this bin would be approximately a thousand tons of sinter.

Below the point 40, which is the juncture of the two conical portions 34 and 36, a bustle pipe 42 is placed around the bin having small feed openings 44 leading into the bin. This pipe will furnish cooling air to the material in the bin, and it ispositioned at thispoint to co-operate with the wideningportions of the bin.

As the sinter progresses downwardly and reaches the widening-portion 34 it will tend to expand 'andloos'en in its density. This permits the air't'o reach all parts of it and to pass then upward through the body ofthe sinter, thus insuring complete cooling throughout the bin. A cover 50 at the top of the bin in conjunction with the cover 30 prevents violentair ejection and th'us'preve'nts the'carrying of fine dust out ofthe bin.

At the discharge portion 38 of the bin an inciincd baille 54 projects across the cylindrical portion just short of a-discharge opening 56. A rotating plate 58 at the bottom of the bin carries the cooled sinter from the'discharge opening 56 onto a rubber conveyor belt 60 leading to the loading point of a blast-furnace or to a stock pile. As the material reaches the rubber, it will be approximately 200 F. or lower and'can be safely handled by the rubber belt conveyor.

With this installation, it will be seen that the sinter can be effectively cooled without the'use of any quenching water or quenching air which has a tendency to break up the sinter lumps. In some cases it has been the practice to add additional wind boxes to the end of a sinter machine simply for the purpose of cooling the sinter. This is an expensive installation as compared with the simple pan conveyor C and also has the disadvantage of the too rapid air quench which tends todestroy the body of the material.

The air which is introduced through the bustle pipe 42 reaches the sinter when it has cooled to a safe temperature and also when it is in a large enough body that there will-be no sudden chilling and destructive cooling effect on the sinter.

Thus, a fine quality of sinter can be obtained which will furnish an efiicient part of the blast furnace burden, being of sufiicient strength to sustain the load of the burden and of sutiicient size to permit even distribution of the chemical reactions in the furnace.

In Figure 2, l have shown a modified cooling bin which may be utilized directly in connection with the end of the sinter unit S.

Referring to the drawing, the grizzlies are sifting devices for the sinter as it leaves the sinter bed and are shown at 70 overlying the hot fines bin 72. Sinter which does not pass through the grizzlies 70 will be directed to the cooling bin 74 which is constructed with an increasing tapered wall 76 which terminates in a cylindrical portion 78 at the widest point of the bin.

Within the cylindrical portion 78 a tapered portion 80 cooperates with an annular plate 82 to provide an annular passage 84 which is connected at diametrically opposed points to branch pipes 86 leading to a main vacuum pipe 88. The bottom section of the cooling bin 74 is formed by two flat plates 90 and 92 which are angled downwardly toward the center of the device, leaving one open quadrant 94. The bottom of the open quadrantis formed partially by the plate 80 and partially by the down chute 96 which provides the outlet for the unit, under which the table 100 is rotated to remove the material to a conveyor such as shown at60 in Figure 1.

A stop plate 102 is provided to dump'the'material onto the conveyor. Triangular gussetplates 106 support the annular plate 82 and join to the bottom plates 90 and 92. Strut plates 110 are provided on plates 90 and 92 leading toward the open quadrant 94. Similarly, downward angled strut plates 112 are provided in the open quadrant over the plate 80.

i The purpose of these strut plates 110 and 112 is to allow the sinter to fill in the spaces betweenthesestruts to form a Wearing bottom .for the unit so that the extremcly abrasive material Will not wear out the bottom of the bin by constant abrasion. These struts swipestioned to direct the material downwardly toward "the open quadrant 94, where it will be discharged.

Cooling of the sinter in the bin is accomplished by suction in the annular passage 84 which is transferred to the bin through E pipes shown in section in Figure 4. These E pipes have a central passage 122 which opens to the annular passage 84. The vertical passages of the E pipes are controlled by dampers 124 and 126. The lower passage of the pipe connects into the bottom of the unit at 128 and the top connects into the unit above the widest portion at 130. These E pipesare spaced around the bin as shown in Figures 3 and 5.

With the damper control, it is thus possible to use only the lower pipes 128 when the bin is just being filled or is almost empty. As the bin fills up the air may be pulled to a greater degree through the openings 130 in the bin, the vacuum being produced by the same general fan that is used for the sinter machine S (Figure 1).

Thus, by cooling with vacuum the dust can be controlled and pulled into a recovery unit where it can be re-used. This device also has the advantage that it adds heat to the fines being recovered so that they are warm as they enter the sintering unit.

The increasing diameter of the bin from the entrance is provided to avoid the abrasive wear above described, and the bottom arrangement is provided to keep the weightof the load in the bin off from the feeder table.

In the initial operation of the device, wind box cooling of the sinter could be used to start the flow of the sinter to the bin 74. As the bin fills'up, the sinter machine could be increased in speed and the sinter would be cooled very gradually in the bin 74, thus avoiding the quenching action which is detrimental to the sinter when it is cooled in the sinter wind boxes at the end of the sinter room.

The device described can be installed for much less money than is required to install extra wind boxes on a sinter machine for cooling, and the design of. the tank is such that it eliminates the constant replacement which would otherwise be necessary in a standard funnel-type bin.

With the present unit, six to ten wind boxes on a sinter unit would be required to produce 1,000 to 1,500 tons of sinter per day, whereas when the cooling is accomplished with a sinter machine for the same production, sixteen wind boxes would be necessary and an expensive rotary cooler would have to be installed. A suitable diameter for'the bin would be about fifteen feet, the bin having an overall height of approximately sixteen feet. The E pipes 120 would preferably be approximately iiiiie inches india rriet'er with about sixteen spaced around the unit.

This application is a continuation-impart of my copending application Serial No. 138,488, filed January 13, 1950, and now abandoned.

WhatI claim is:

1. LA sinter cooling bin which comprises a relatively large, circular bin having an open top and side walls tapering outwardly fromthe open top, sinter supporting means at the bottom of the bin comprising stationary plates angled to a discharge opening, and means on said plates also angled toward said opening'to collect a compacted layer of sinter material to provide a wearing surface for the bottom of the bin, said surface angling toward "said opening.

2. A cooling bin for sinter discharged from a sinter machine which comprises a large bin circular in cross section having an open top to receive sinter, and side walls tapering from said open top outwardly and downwardly toward the mid-portion of the bin, means forming a discharge opening at one quadrant of the bottom portion of said bin, and bottom plate means extending from the side walls of said 'bin toward said discharge opening, vertical jstr ut mean s on said bottom plate means extending from the side walls to saiddiseharge opening ito'caus'e a compaction of sinter to create "a wearing surface for the bottom of the bin, means forming a suction air passage between the side walls of said bin and said bottom plates, and means for feeding air from said bin above and below said suctioii air passage to said passage to provide cooling of the contents of the bin.

3. In a sinter cooling bin, a bottom formed by supporting plates angled from the outside of the bin to a discharge opening at the bottom of the bin, and strut means extending along said plates substantially in a direction toward the discharge opening, the top edges of the struts lying at a greater angle to horizontal than the supporting plates to provide open-topped pockets for a compacted layer of sinter material to create a wear bottom for said bin, said wear bottom to lie along the top edges of said plates and tapering toward said opening.

4. A sinter cooling bin comprising a circular open top, retaining means tapered outwardly and downwardly from the top to a mid-portion thereof, means forming a conical inwardly directed wall centrally of said bin and serving also to create one wall of an annular suction passage within the confines of said bin, an annular plate means forming a third wall for said annular passage, bottom plate means completing said bin angling downwardly toward one segment of the bin, means forming an outlet passage at said segment, and means forming air passage outlets for said bin above and below said annular passage and connected thereto whereby suction created in said annular passage will draw air from the inlet and the outlet of said bin to said passage through sinter material within the bin.

5. A sinter cooling bin as defined in claim 4 in which guide plate means are vertically disposed on said conical plate means and said bottom plate means extending toward said discharge opening to provide pockets for a compacted layer of sinter material passing through said bin.

6. A sinter cooling apparatus which comprises a relatively long, open, continuous conveyor having one end positioned to receive sinter on the top pass of the conveyor from a continuous sintering machine, the conveyor extending upwardly at an angle from the receiving end to a discharging end, a cooling bin at the discharging end comprising a substantially cylindrical container open at the top end having a widened portion adjacent the midsection to provide a substantially increased area at that portion, a bustle pipe for injecting air into the bin connected to the bin at spaced intervals around the circumference thereof, a narrowed portion at the discharge end of said bin having a side opening, a bafile plate angled in the bottom portion to said opening, and a rotating discharge plate at the discharge end of said bin underlying said plate except at said opening to carry cooled sinter from the bin through said opening.

7. In a sinter cooling apparatus of the type to receive sinter from a continuous, open, conveyor, a cooling bin positioned to receive partially cooled sinter from the top pass of the conveyor comprising a stationary cylindrical container open at the top and bottom and having a substantially widened portion centrally located adjacent a plurality of circumferentially spaced air inlets for cooling air.

8. A sinter cooler as defined in claim 7 in which the bin is substantially narrowed at the bottom to support the load of the contents on the walls of the bin, an opening formed in the side of said narrowed portion, a load baflle angled in said narrowed portion toward said opening from a higher point in said bin, and a rotating plate at the bottom of said opening underlying said plate except at said opening to carry sinter from said bin out of said opening.

9. Apparatus'for the cooling of hot sinter with air flow, which comprises, a relatively large, open-topped bin substantially circular in horizontal section and having a top entrance, said bin having a substantially cylindrical shape extending downwardly from the open top about one-half the vertical height of the bin, an intermediate section directly below said' cylindrical section having conical frustum shape flaring outwardly and downwardly to a maximum diameter terminating about onethird vertical height from the bottom of the bin, the remainder of the bin comprising a conical frustum section extending inwardly and downwardly from the maximum diameter to a discharge opening at the bottom, an air flow distributor means around said bin directly adjacent the top of the lower conical frustum section at a diameter greater than the upper cylindrical portion for introducing cooling air at circumferentially spaced points into the bin directly below the maximum diameter thereof into a charge of sinter within the tank to cool the same prior to discharge from the bin.

References Cited in the file of this patent v UNITED STATES PATENTS Bonneville July 7, 1891 552,127 Howie Dec. 31, 1895 779,106 Wegner et al. Jan. 3, 1905 1,102,714 Bornmann July 7, 1914 1,545,060 Moetelli July 7, 1925 1,669,012 Nordstrom May 8, 1928 1,742,709 Kenigsberg Jan. 7, 1930 1,960,522 Alexovits May 29, 1934 2,012,881 Lee Aug. 27, 1935 2,153,112 Windecker Apr. 4, 1939 2,329,948 Shallock Sept. 21, 1943 2,336,378 Uhlig Dec. 7, 1943 2,393,227 Anderson Jan. 22, 1946 7 2,393,893 Evans et al. Jan. 29, 1946 2,532,335 Royster Dec. 5, 1950

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