US2315022A - Apparatus for treating materials - Google Patents

Description

APPARATUS FOR TREATING MATERIALS Filed May 8, 1941 s Sheets-Sheet 1 mvmok BENJAMIN A. SMITH Arromvavs March 30, 1943. B. A. SMITH APPKRATUS FOR TREATING MATERIALS Filed May 8, 1941 3 Sheets-Sheet 2 I \INVENTOR. BENJAMINASMITH "TIE--7 B March so, 1943. B sM 2,315,022

APPARATUS FOR TREATING MATERIALS Filed May 8, 1941 3 Sheets-Sheet 3 INVENTOR. BENJAMIN A.'SM|TH ATTORNEYS v? ,KAMQQW Patentecl Mar. 30, 1943 APPARATUS FOR TREATING MATERIALS Benjamin A. Smith, Rocky River, Ohio, assignor to The C. 0. Bartlett & Snow Company Application May 8, 1941, Serial No. 392,479

Claims.

This invention relates, as indicated, to apparatus for the treatment of materials, and this invention particularly relates to apparatus for the preparation of charges of raw material prior to their introduction into conventional furnaces, usually of the electric type, employed in the manufacture of metallic alloys.

The manufacture, or more particularly, the smelting of metallic alloys, usually accomplished by a reduction of the ore and frequently the smelting therewith of a certain amount of scrap metal, is generally carried on in an electric furnace for the reasons well known in the art. While it is usually necessary and desirable to carry on the final smelting operation under the carefully controlled conditions possible in an electric furnace, it is generally not necessary to heat the 'material from its cold state in the electric furnace. If the ingredients or constituents of the final charge can be heated properly up to a temperature below which the carefully controlled conditions existing in the electric furnace are not necessary, then hydrocarbon fuels may be employed to efiect such initial heating with a consequent saving in total cost.

It is the principal object of my invention to provide apparatus by which the above-referred to preliminary heating of the charge constituents may be advantageously and economically effected.

It is a further object of my invention to provide apparatus of the character described characterized by the fact that the preliminary heating of the raw materials is effected in a most economical manner and in such a way as to insure that the charges supplied to the electric furnace for the final heating, reduction or smelting operation may be uniform as to quantity and quality so as to insure maximum efficiency of operation of the electric furnace and uniformity of the product produced thereby.

Other objects of my invention will appear as the description proceeds.

To the accomplishment of the. foregoing and related ends, said invention, then, consists of the means hereinafter fully described and. particularly pointed out in the claims; the annexed drawings and the following description setting forth in detail certain means and one mode 11- lustrating, however, but one of the various ways in which the principle of the invention may be used.

In said annexed drawings:

- Fig. 1 is a plan view showing somewhat diagrammatically one form of apparatus capable of carrying out the principles of my invention;

Fig. 2 is a side elevational View, partially in section, of one of the units which comprise the combination illustrated in Fig. 1;

Fig. 3 is a transverse sectional view drawn to an enlarged scale of a portion of the apparatus illustrated in Fig. 1 taken on a plane substantially indicated by the line 3-3;

Fig. 4 is a transverse sectional view of a portion of the structure illustrated in Fig. 3, taken on a plane substantially indicated by the line 4-4; I

Fig. 5 is a fragmentary sectional view of a portion of the apparatus illustrated in Fig. 3, taken on a plane substantially indicated by the line 55;

Fig. 6 is a transverse sectional view similar to Fig. 3 illustrating a modified form of construction; and

, Fig. '7 is an enlarged broken-away sectional view of a part of the apparatus shown in Fig. 6.

Broadly stated, this invention comprises apparatus for the preliminary heating of charges of raw material such as may be introduced into 'an electric metallurgical furnace characterized in that separate heating kilns are employed for such constituents as it is convenient or desirable to preliminarily heat separately before introduction into the smelting furnace. Such kilns are preferably sufficiently large in capacity to accommodate a quantity of impounded raw mate rial substantially greater, and for most purposes several times the quantity of, individual charges of the particular impounded material.

The impounded material may be heated by some relatively inexpensive hydrocarbon fuel and at a substantially uniform rate so that when the impounded material, as it is depleted for the purpose of charging the'smelting furnace, is replenished at such a rate as to maintain substantially constant the temperature of the kiln within which the preliminary heating is eifected.

Referring now more specifically to the drawings and more especially to Fig. l, the arrangement here illustrated is a plan. view of a conventional installation constructed in accordance with the principles of. my invention. The electric furnace or similar smelting furnace, generally lndicated at I is of course the smelter or melting device which is to be supplied with charges of raw material by the process and apparatus of my invention. The numeral 2 denotes the location of a crane cab, such crane operating, for example, along the line generally indismelted. For purposes of illustration; only two of such kilns have been shown sincethe principles of my invention apply without substantial modification to an arrangementcornprising a greater number of such kilns. Throughout-- the ensuing description it will be assumed therefore, for the purpose of simplifying this description that thechargefto be suppliedtothe-fu rnace I will consist of twoprimary constituents, for con- 'ven'ience referred toa'stheore and lime.- -I't is assumed; therefore, for I purposes of illustration in describing theinventiony-thatthefurnace -I Y is a reduction furnace to be supplied: with charges consisting of pre-determ-ined amoutsof oreand lime. For the manufacture of more complex metal alloys it may, of'course;-'- be desirable, as

above pointed out,'to maintain as separate. units a greater number of the charge constituents requiring theuseof--a correspondingly greater number of separate kilns. I y It islikewise within the contemplation of my invention'toemploy a single pre-heating kiln into which may beintroduced a mixture of all of the ingredients andin the proper proportions *re- U =quired for the charge tothe'smelter. This-may *be necessary'anddesirable wherethe natureof the charging materials is such that they-may be advantageously or desirably pie-heated while mixed togetherm l Each of-'=the kilns-comprises a substantially :cylindrical refractory lined unit generally indicated at e 6,- provided with circunirerentially extended supporting rings] which" ride on spaced rollers 8,- all thisbeing} of eourse, wel1 recognized structural design for the supportof kilns of this character. -Each kiln. will be providedwith an annular-drivinggear 9 which will be in mesh .with a driivng pinion and its asso'ciated speedreduc- 'tion-mechanism anddriving-motor, not shown. These last-named elements have. beenomitted from the illustration-in order .toclarifythe drawings. It'will-b noted, however, .thatthe driving means forpthe kilns 6will be..capable of selectively driving eachkiln in opposite directions. Each kilnmay be provided with a feed. hopper l containing th cold raw material which may be 'fed theretosbyany-suitable means ;such. as k a screw conveyor, generallyindicatedat:H. The hopper H] may, of course-be supplied with raw material-from a bin, generally indicated at 12, and buckets 'or cars such :as I3' may, of-course,

be employed for the purpose. of. conveying the.

raw material from the bin'tosthe hoppersnIt .is, of. course, within the 'contemplation of myinventionto variously arrange the supply ofuraw materialso as to' maintain in .the hopper. I0 an adequate quantityof the sametobe fed into the;

; kiln Bbythe feedingdevice 1 Li If. desired, the feeding *device, llandtits associated hopper. IE! maybe moved on a platform. I 4 which, mounted on -rollers, maybe moved to and rromithei feed- Working parts, and if desired, the feeding device, generally indicated at Il, may be moved into feeding relation with the kiln 6 during only such intervals as it is necessary in order to keep the 5 kiln 6 supplied with the necessary quantity of impounded material to be heated in preparation for the charge. In such case the opening through which the material is fed to the kiln 6 may be closed by some removable device which 10 would assist in conserving the heat within the kiln 6.

At the opposite end of the kiln S from the feedingdevice His a hydrocarbon fuel burner generally indicated at! 5 and it is within the contemplation of'myinvention to employ any suitable fuel in such burner, such as, for example, gas, oil or-powdered coal. This burner heats the material internally or directly.

The stack opening from the kiln 6 will pref- -erably be. in the sameend with the feedingopening, for example, thestackopening may be concentric withmhe feeding opening, in which case .thefluctpr flue. l6;may,extend downwardly and lead.:to the main stack for theplant.

5 1 Each :kiln 6 .will be, at some, convenient location preferably adjacent the-send oe upi d b t hydrocarbonburner, provided with a discharge ring, .generally indicated at l1 the construction anda mode of. operation of which may be more readily determined by having reference to Figs.

..Refe11fing n0w.-t0-1E s-.. ,-t e en er er he ye the kiln 6. is indicated by theline l 8. .Within the cutershell.tneidlnsspfeceu s pro i w e refractorylining which extends inwardly. to the n I fil sa est; shown i .-r, r g d, i a

. circumferentially ex tending groove on the inner p ip ery e iih s reir q rn i i e e P erality; ofco mplementary v segmental members,

I generally nd c ted. at 2,"- lTb S Segmental me berswill be of some suitable high-temperature- .re siente lpren se s e t l rectangular in shape with a semif-cyiirrdrical shaped. topfportion 20' each providingashort circumferentiallyflextending laterally restricted passage for, the flow ofIjrnaterial fromftheintrior, of, the kiln to the outsidethero f, showniinFigthe level I9 of the'jr'efractdry 'li'ningfextendsonly to the top of the parallel sidewalls of the units 20. The top 29 is .rnade se mi-cylindrical in shape in order to impart strength thereto for preventing buckling of'the same after beingheated. One end of each of these ,s'eg'rnerrtal uhits Z'Q is provided on its inner face with an opening 2| and the opposite "endsrdf these segmental are respectively "provided with butwardly extending throats 22.

The several segmental units are provided with circu'mferen'tially extending fingers 23 which, when the several units a'reass embled in the manner illustrated in Figs ii and'at their outer ends bolted to the shell-of the kiln fi will lock and these'segmental unitsagainstdisplacmentr The V casing 24 around the kilnj in the circumferential area occupiedby the segmental units 20 is for the pi'irpose cf collecting the material discharged fromithe'kilmand a suitable spout such as 25 may be'provide'd to-ca'rry the discharged materialinto I a car or bucket26 which-will-be supported for conven'ienc'e'on a weighing scale platform ZLby which the quantity. (if material iiischargedfona. particular charge may'beTaccuratelydetermined.

It will be observed that when the kiln rotates in the direction indicated by jthearrow 28;.in.Fig.

ing openingin theikiln 6, This arrangemehtperig. -.3 the.materia.l withinsthelkilnwill be scooped up v mits ready inspection and repair of the various through the openings 2| by the segmental members 2B and as eaclrsegmental member moves to the lowermost position the contents of the passage through such member will be discharged into the spout 25. If, however, the kiln is rotated in a direction opposite to that of the arrow 28 the material will be prevented from flowing out through the segmental members and the material which falls into the openings 2! will drop back into the kiln upon movement of such openings to the top of the kiln.

In the operation of the apparatuses above described in carrying out the principles of my invention, the ore and lime, for example, shall go to make up the component parts of the charge for the furnace which will be introduced into the respective kilns 3 and 5. A sufficient quantity of raw material will be maintained in each kiln at all times so as to more than supply the requirements for a single chargefor the furnace I. In fact, it will be found desirable in certain instances to impound enough material in each kiln to supply the requirements of several individual charges. Thus, a residual charge of hot material is left in each kiln at all times. When heated material is wanted for the furnace charge the kiln, normally rotated in such a direction as to retain the material therein and to agitate the same so as to insure its being uniformly heated, will be stopped and rotated in the opposite direction. This will result in a discharge of the heated material from the kiln so reversed, and the discharged material will flow into the car 26 where it can be weighed and the rotation of the kiln in the discharging direction stopped when the desired amount of material has been withdrawn. The car 23 will preferably be refractory lined, covered and thermally insulated to preserve the'heat of the material therein during the time when the car is transferred by means of the crane or otherwise over to the furnace and its contents charged into the furnace. It will be observed that the discharge point in the kiln is substantially removed from the charging point, and if a sufficient quantity of raw material is impounded in the kiln it may be entirely feasible to feed the raw material into the kiln at a continuous uniform rate. Thus it is feasible for certain types of material, and where the impounded quantity of raw material is great enough, to continue the feeding of the cold material into the kiln simultaneously with the withdrawal of hot material therefrom. For certain types of material it may be found desirable to interrupt the feeding of cold material into the kiln for an interval shortly prior to the time when a charge is to be withdrawn from the kiln.

It will be observed from the foregoing description that I have provided apparatus for preliminarily heating the charges for metallurgical furnaces characterized by the fact that this preliminary heating of the raw material may be carried on in a substantially continuous manner so as to utilize to the fullest extent the heat of the preliminary heating medium. Furthermore this process insures the necessary supply at all times of the components of the charge for the furnace and at uniform conditions particularly with respect to temperature; the preliminary heating being accomplished by the use of relatively inexpensive fuel, the process comprising my invention materially reduces the total cost of the smelting operation.

It is further frequently found desirable to accomplish the preliminary heating in an oxidizing atmosphere to the end that free carbonaceous materials contained in the ingredients entering into the furnace charge, may be fully oxidized and converted to gases which pass out of the preheater apparatus thereby greatly assisting the control of carbon in the alloy'subsequently produced by the furnace.

In Figures 6 and '7, there is shown a modified form of construction of the units 20. In this showing like numerals have been used to designate like parts and it will be understood that the manner of operation of such modified construction of the units 20 is essentially the same as described for the construction shown in Figure 3. The dilference in the showing of Figures 6 and 7 lies mainly in a change in the shape of the throats 22 and in a change in the interlocking connection of the various units 20 by which the fingers 23 of Figure 3 are eliminated. The throats 22, instead of being inclined as shown in Figure 3, extend in a radial direction with respect to the kiln. In place of the interlocking fingers 23, each unit is provided with a transversely extending ledge 38 at the end thereofadjacent the discharge opening 22 which is adapted to interlockingly engage with the top 3| of an endwall 32 of the next adjacent unit 20 as best shown in Fig. 7. Each of the ledges 30 defines the upper edge of an opening in one of the units 20 in which the endwall 32 of the next adjacent unit 20 is receivable. In this manner, each endwall 32 functions as an endwall for each of adjacent units and is eifective to separate the circumferentially extending passages 33 of adjacent units 20 from each other. In assembling the units 20, the flanges 34 of the throats 22 are bolted to the liner 18 to secure one end of each unit 20 in position as shown in Figure '7, the other end of each unit 20 being held in position by the interlocking engagement of the ledge 30 with the top 31 of the walls 32. In this manner, the ledge 30 is made to serve the same purpose as the fingers 23 of Figure 3.

Each of the units 20 may be provided with a transversely extending ledge 35 adjacent the openings 22 as shown in Figures 6 and 7, for restricting passage of material out of the passages 33 when the kiln is rotated in a clockwise direction. When th kiln is not discharging and is rotating clockwise, material will fall into the openings 2| as such openings move under the material within the kiln. The ledges 35 will be found eifective to prevent such material from dribbling and falling out the openings 22 as such openings approach their lowermost position in a clockwise direction. A rib or ledge 36 may be provided, as shown in Figures 6 and '7, adjacent the opening 2| for the purpose of reinforcing that portion 20' of the units 20 which defines the opening 2!.

This application is a continuation in part of my co-pending application Serial No. 159,140 which has now matured into Patent No. 2,241,429.

Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the means herein disclosed, provided those stated by any of the following claims or their equivalent be employed.

I therefore particularly point out and distinctly claim as my invention:

1. In apparatus of the character described, a rotatably supported cylindrical kiln, and means operable upon rotation of said kiln in one direction to discharge material therefrom, and operable upon rotation of said kiln in an opposite direction to retain material therein, comprising, a plurality of like members arranged circumferenin a segmental I annular passage" and having an I said interlocking means cotfi iri'ss finger members is'preiiiaed 'wrthen opening, thend or the next 'eajaeent uiiit hav'i'ngan end wan receivable in said opening for interleckmg said units in posibion, "sa'idkiidfill being effective to separate "djbicht segmental annular passages "from each ether. 4 I

"BENJAMIN A. SMITH.

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