US1857919A

US1857919A - Feeding mechanism for roasting furnaces

Info

Publication number: US1857919A
Application number: US345325A
Authority: US
Inventors: Kunkel Richard Cooper
Original assignee: General Chemical Corp
Current assignee: General Chemical Corp
Priority date: 1929-03-08
Filing date: 1929-03-08
Publication date: 1932-05-10
Anticipated expiration: 1949-05-10

Description

May 10, 1932- I R. c. KUNKEL 1,857,919

FEEDING MECHANISM FOR ROASTING FURNACES Fild Maron 8, 1929 RICHARD /l/umrEL Patented May 10, 1932 teren STATES PATENT; "iol-FICE RICHARD COOPER KUN KEL, OF PULASKI, VRGINIA, ASSIGNOR TO GENERAL CHEMICAL COMPANY, OF NEW YORK, N. Y., .A CORPORATION OF NEW YORK z FEEDING- MECHANISM FOR ROASTING FURNACES Application mea March s, '1929. serial No. 345,325.

This invention relates to furnaces for roasting granular material such for example as ore and the like, and is especially concernedwith the feeding of the granular material to the furnace. 'Such roasting furnaces are provided with stationary hearths upon which the ore is stirred and distributed by rakes or ploughs aflixed to a rotating arm. The ore is fed in at the topof the furnace to the uppermost hearth and proceeds downwardly from hearth to hearth in its progress through the furnace.

It is desirable that the ore or other granu- I lar material be fed to the furnace periodical-y ly and in regulatable quantities, and it is important that it be admitted to the furnace without the admission of air when the apparatus is operating under a negative draft and to eliminate the loss of furnace gases when the apparatus is operating under a positive draft. It is also important that the apparatus be capable of ready adjustment and be so designed that it is not affected'by corrosion caused bythe gases within the furnace.

Roasting furnaces have heretofore been provided with feeding mechanisms of lcomplicated design, expensive in first cost and in upkeep, and which moreover have not been provided with proper means for preventing the entrance of air or the escape of furnace gases. In some of these former feed mechanisms also the working parts soon became badly worn either through mechanical wear or corrosion, and because of theircomparative inaccessibility it has been difficult to replace such parts.

The present invention is directed to the overcoming of such diiiculties as these, and it has for its principal object the provision of a feed mechanism which will provide a positive gas seal without the use of complicated mechanism.`

Another object of the invention is to provide a feeding mechanism which will supply the ore to the furnace periodically at a uniform rate, that is, although the ore is fed to the furnace inbatches rather thancontinuously, nevertheless the amount of materiai in each batch is substantially the same.

A further object of the invention is the provision of a feeding mechanism which is so. constructed that 1t 1s easy of access and easy to adjust;

Another object of the invention is to prol duce a feeding mechanisnrwhich is low in first cost of installation, which is not subject.,

The preferred embodiment of the invene,

tive idea is shown in the accompanying drawings, in which,

Fig. 3 is a somewhat enlarged section taken.` through the ore admission valve.

Referring now to the accompanying drawings, the furnace comprises a cylindrical casing 10 provided with a series of superposed floors, of which onlyk two are shown and in k dicated in Fig. 1 by the reference characters 11 and 12, the floors being alternately provided with apertures 13 at the periphery and apertures 14 at the center. The furnace is provided with a roof 15, and the floors'll).

and 12, together with the similar floors be# low them, constitute vthe burning hearths. rfhe gaseous products pass out through an opening (not shown) in the cylindrical walll() above the uppermost floor 11.

Extending vertically through the center of vthe furnaceis a rotatable shaft 16, to which is affixed a plurality of horizontally extending stirrer or

rabble arms

17 and 18. The arms 17 are providedy with defiecting projections 19, which work the ore towards' the peripheral openings 13', and arms 18 have similar projections 2O arranged to work the ore in an opposite direction towards the central. aperture 14;

The ore is fedto the furnace through the 32 adjustable.

per 2l will descend onto shelf. 23 until the pile reaches the lower edge of the mouth. The mouth 22 is vertically adjustable by means (not shown) so as to vary the elevationof itslower surface with respect to the shelf 23 and in this way regulate the size of the pile of ore on the shelf.

There is an aperture in the roof l5 of the furnace at one side of the shelf 23, as may be seen in Fig. 2, yand in this aperture there is placed a cylindrical member 24 preferably 'of cast iron. Cylindrical member 24 is pro l vided with a deep recess or pocket 25 on its upper side, and m the bottom of the member there is a conical valve opening 26. A heavy conical-shaped valve plug 27, also preferably of cast iron, fits the valve opening 26, and is adapted to be raised and lowered by means of a stem 28, which is attached to the end of a lever 29 fulcrumed at 30 to a bar 3l preferably bolted or otherwise securedv to the cylindrical member 24.

A blade or sweep member 32 is mounted upon a bracket 33 secured to the upper portion of rotating shaft 16. This mounting comprises a pair of bolts 34 passing through a slot 35 so as to make the position of blade The rotationV of shaft 1 6 in the direction of the arrow shown in F 1g. 2

causes blade 32 to sweep ore from the pile on shelf 23 into the pocket 25 of the cylindrical member 24.

The free. end-of lever 29 is curved upwardly as shown in Fig. 3 into the path of the blade 32, so that shortly after blade 32 has swept the ore into the kpocket 25, blade 32 engages the lever 29 and causes the valve plug 27 to be automatically raised so that the ore in the pocket 25 runs through the valve open-` ing 26 onto the upper shelf l1 of the furnace. As soon as the blade 32 passes the upturned end of lever 29, the valve plug 27 again drops into the valve opening. p If blade 32 is notof' the right width, or if the blade rotates vtoo fast, the valve plug 27 will drop into the valve opening before all of the ore which has been swept into the pocket 25 has had a chance to pass into the roaster. This is adjusted however' by loosening the bolts 34 and adjusting blade 32 so that it will sweepless ore from the shelf 23 into the pocket. In other words, the radius of the circular path of the outer end of the blade as indicated by the dotted line in Fig. 2, is decreased. If it is desired to increase the amount of ore fed to the roaster, additional blades 32 may be mounted upon shaft 16, or if desired one or more additional hoppers 21 as indicated by the dotted lines in Figs. l and 2, may be used. The progress of the ore from hearth tov heart through the furnace depends however upon the spe-ed'of rotation of shaft l6,and with the feeding mechanism of the present invention, the rate at which the ore is fed to the roastcr or furnace depends directly upon the speed of rotation of this same shaft. Hence the ore automatically is fed in at the top of the roaster at a rate corresponding to its progress through the apparatus.

The rate at which the ore can be roasted in the furnace isdetermined by the area of the superposed floors which4 constitute the burning hearths, and the speed of the rabble arms 17. It is therefore an easy matter to maire the valve opening 26 of the proper size and the blade 32 of the proper lwidth to cause the feeding mechanism to supply the proper amount of ore for any given furnace.

it will be understood that in the operation of the ore feeding mechanism, the blade 32 first sweeps a quantity of ore into the pocket before the valve plug 27 is raised so that at the time this occurs pocket 25 is filled with ore co'xf'ering the valve plug and opening as shown in l. riherefore as the valve is opened, the ore pile in pocket 25 immediately begins to flow down through the opening 26. rl'he quanity of ore inthe pocket 25 is adjusted as previously described so that the plug falls into the valve opening just as the last of the ore pile runs through the opening 26. Illhe plug remains in its seat until another quantity of ore has been swept into the pocket 25. rhe feeding mechanism therefore provides a positive gas seal at all times except' vhcn the ore is actually running through the entrance opening 26 and during this time the flow of the ore itself provides a comparatively effective seal. Hence if the pressure on the interior of the furnace is less than that of the atmosphere, as is the casewhen the furnace operating under a minus or negative draft, it is impossible for any appreciable amount of air to enter the furnace, and similarly the furnace gases are prevented from escaping when the pressure within the furnace is greater than that of the atmosphere.

Another advantage of my improved feeding inecnanism is that it provides a sharp cut-off of the flow of ore into the furnace because after the ore within the pocket has been discharged through the opening 26 and the valve plug 27 comes down to its seat, it impossible for any further ore to enter until the plug is again raised. in a number of the feeding mechanisms of the prior art, the stopping of the flow of ore is not positive and the ore continues to enter the furnace after the mechanism has operated to cut off the supply. This isa disadvantage because l construction, and also as it is easyof access,

it can be replaced at low cost.

. The cylindrical member 24 is of sufficient diameter and depth so that the pocket 25 will hold the desired amount of ore, and by plac-V ing theconical valve opening 26 slightly to one side of the center, the entire valve and valve operating mechanismV is made as a uni.

tary structure so that if it is necessary or desirable to make a replacement the entire mechanism can be readily removed simply by lifting the member 24 out of its seat in the feeding hole in the roof of the furnace.` Then another valve mechanism can be quickly inserted in its place and hence the change can be made without interruption in the operation of the roaster.

In order to facilitate the insertion and removal of the valve mechanism, the body 3G of the cylindrical member 24 is made with a fairly quick taper and the feed hole is correspondingly tapered. Also a ange 37 is provided at the upper periphery of the member 24. Member 24 is hence a sort of pot shaped casting which can be easily placed in or moved from the feed hole and engages the surfaces of the feed hole so as to make a tight seal and so as to hold the casting firmly in position against the tendency to displace the same caused by the coaction of blade 32 with lever 29.

The foregoing is considered to be an eX- emplifying disclosure of the feeding mechanism of my invention, and the invention includes such modifications as come `within f the scope of the appended claims.

I claim l. In a roasting furnace having a feed opening, a closure for the feed opening, means including a movable sweep for periodically depositing in the vicinity of the opening so as to be held back by the closure a quantity of granular material to be treated in the furnace, positively `operated means actuated cinity of the opening so as to be held back by ltimes against the passage of gas.

the closure a quantity of granular material to be treated in the furnace, and'means actuated by said shaft synchronouslywith the periodical deposition of the granular material for opening the closure to allow the material to pass through the feed opening into vthe furnace, and closingthe closure when the flow of the material therethrough is substantially completed. n -v 3. A roasting furnace having a feed open'-` ing comprising a member having a pocket therein for'holding a quantity of granular material to be fed to the furnace, the member having an aperture in the bottom of the pocket, a valve plug seated in the aperture, means for periodically depositing material in the pocket, means for raising the valve plug against the pressure of theimaterial in the pocket to allow1 said material to` run, through the aperture into the furnace, land means for lowering thevalve plug and closing the aperture substantially simultaneously with the completion of the iow of said material, whereby said aperture is sealed at V4. In `a roasting furnace having a feed opening, the combination of a fixed shelf disposed near thel feed opening, a closure for said opening, means for periodically transferring a quantity of material from the shelf into the vicinity of the feed opening, means actuated synchronously with the periodical transfer of material from the shelf for opening the closure to permit the material to pass y. through the opening into the furnace, and means for closing the closure immediately thereafter.

5. In a roasting furnace having a feed opening and a rotating shaft, the combina;`

tion of a shelf disposed near the feedopening, a closure for said opening, meansY actuated by said shaft for periodicallytransferring a quantity of material 'from theV shelf to the vicinity of the feed opening, means actu-H ated by said shaft for opening the closure to permit the material to pass through the feed opening into the furnace, and means actu'- ated by the shaft for closing the closure substantially simultaneously with the completion of the flow of the material through the' feed opening.

6. A roasting furnace having a feed opening provided with a pocket surrounding the same, a shelfvdisposed above and at one side of the feed opening, a closurefor said opening, means for periodically sweeping a quantity of granular material from the shelf into the Vpocket of the feed opening, means for periodically openingthe closure against the pressure of said material to permit the material to pass through the opening into the furnace, and means for periodically closing 'the closure approximatelyV at the end of the flow of said quantity of material. A Y

7. A roastingvfurnace having a feed open- .ing in the roof thereof, :a rotating vertical when the flow .of the material is completed.

8. A roasting furnace having a feed open- :ing inthe roof1 thereofaud a rotating shaft extending upwardly from the roof, a shelr disposed above and .at .one side of the feedy opening, a hopper having a discharge mouth disposed somewhatabove the surface of said Shelf so .as .to Vmaintain a substantially constant supply ofgranular material on the shelf. to be fed to the furnace, .a closure for the feed opening, a blade fixed to the rotating shaft and `adapted to .move over the surface of the table below said discharge mouth and periodically sweep a quantity of the granular material from the shelf into a position covering the closure and the feed opening, means on the shaft for opening .the closure against the pressure of the .granular material., and means also on the .shaft for lclosing the closure substantially as soon as the quantity of material has run through .the opening into the furnace..

9. A roasting .furnace having a. feed opening in the roof thereof and a rotating .shaft extending upwardly from the roof, a shelf kdisposed above and at one side of the feed opening, a closure for said opening, a blade fined .to rotate with Said shaft .and move over said shelf and sweep :a quantity of granular material therefrom into the vicinity of the feed opening .and cover the closure therefor, and means actuated by said blade for opening the closure against the pressure of the material and causing the closure to close the feed opening substantially as soon as the quantity of material has run through the feed opening -into the furnace.

10. A roasting furnace having a feed opening in the roof thereof and a rotating shaft extending upwardly from'the roof, a shelf disposed above and at one side of the feed opening, a vertically movable plug for closing the feed opening, a pivoted lever for raising the plug out of the opening, a blade 'secured to said rotating shaft and adapted to pass over the shelf and sweep therefrom a quantity of material on and surrounding the plug While it remains in closed position, said pivoted lever having a cam surface extending into the path of said blade and adapted .to be engaged thereby after the blade has passed the shelf and raise the plug against the pressure of the material, the plug falling under the linfluence of gravity after the blade has passed said cam surface and there- :by Aclosing the feed opening after the matcri-al has passed therethrough to the furnace.

1l. In a feeding mechanism for roasting furnaces, a unitary feeding device for insertion lin the feed .opening of the furnace comprising a member having a pocket in the upper side thereof, a feed opening in the bottom thereof, a vertically movable plug for closing said feed opening, and a lever for raising said plug .out of the feed opening fulcrumed `to the side of said member.

12. In a roast-ing furnace having a rotating shaft andv a feed opening, a shelf posi- .tioned above and at one sideof said feed same time that the valve plug is lowered to P close the opening.

RXGHARD [COOPER KUNKEL.

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