US2980349A - Furnace chunk breaker - Google Patents

Description

April 18, 1961 F. J. BORON FURNACE CHUNK BREAKER 2 Sheets-Sheet 1 INVENTOR. FRANK J. BORON Filed April 11, 1958 ATTORNEYS April 18, 1961 F. J. BORON FURNACE CHUNK BREAKER 2 Sheets-Sheet 2 Filed April 11, 1958 INVENTOR. FRANK J. BORON ATTORNEYS FURNACE CHUNK BREAKER Frank J. Boron, Elyria, Ohio, assignor to American Brake Shoe Company, New York, N.Y., a corporation of Delaware 7 Filed Apr. 11, 1958, Ser. No. 728,010

9 Claims. (Cl. 241- 67) This invention relates to the construction of equipment for a furnace of the kind used to fire ore-bearing material or the like incidental to the processing of'such material, and the present invention is concerned in particular with the construction of oscillating shafts that are mounted adjacent the furnace and which are to be provided with discs for breaking up the material processed in and emitting from the furnace.

In one form of furnace installation used to process ore-bearing material and the like, the material which is fired in the furnace is funneled out the bottom of the furnace, and spaced parallel rotating shafts composed of steel are interposed to assist in breaking up the fired material emitting from the furnace so that the material is subdivided prior to falling onto transfer belts. Such shafts are provided with so-called breaker discs composed of steel and secured thereto, and the breaker discs are formed with teeth about the outer peripheries thereof which assist in breaking up the burden much in the manner of oscillatable furnace grates. Heretofore, the discs have been joined directly to the shafts, that is, there is a continuous line contact between the adjacent surfaces of the shafts and the discs, and because of the high temperatures encountered the shafts are arranged for water cooling by directing cooling water through hollow internal areas formed in the shafts which prolongs the life of the shaft and the discs.

For the most part, it is the breaker discs which accomplish the work by crushing the material fed to and emitting from the bottom of the furnace. In more recent years, however, higher and higher temperatures are being resorted to in such furnaces, and it is now recognized that in order for the, breaker discs to have an appreciable life it is necessary to compose the, breaker discs of expensive heat-resistant alloy. On the other hand, it is desirable to construct the-supporting shafts for the breaker discs ,of steel having good heat conductivity, but steel of course hasa quite different coeflicient of thermal expansion compared to a heatresistant alloy such as an alloy composed of 10 to 30% chromium, to 30% nickel, 0.1 to 20% manganese, 0.1 to 0.8% carbon, remainder substantially all iron with a 3% maximum tolerance in silicon. This difference in thermal coefiicient characteristics coupled with the watercooled steel shaft introduces a serious problem insofar as the thermal stressing of the alloy discs is concerned, and itis the primary object of the present invention to enable chunk breaker discs composed of a heat-resistant alloy such as the foregoing to be secured to a watercooled steel shaft under such circumstances that the likelihood of severe or undue thermal stressing of the alloy discs is greatly reduced.

Thus, in contra-distinction to prior and existent arrangements wherein the breaker discs are secured to the shafts either by a continuous line contact in the nature of a press fit or continuous 360 welds, alloy breaker discs in accordance with the present invention: are

United States Patent O mounted on the shafts with as little contact as possible between the adjacent surfaces of the shafts and the discs. This is accomplished under the present invention by specific modes of establishing a spaced union between the discs and the shaft, and these are exemplified in all instances by first of all cavitating or hollowing the inner diameter of the discs to afford a U-shaped section defined by spaced apart thin arcuate rims thereby reducing the area of the discs which are immediately adjacent or opposite the outer diameter of the shaft on which the discs are mounted. In order to establish spacing between the narrow rims of the discs andthe adjacent surfaces of the shaft, the rims of the disc are of larger inside diameter than the outside diameter of the shaft, and a drive connection of very limited surface contact is established between the discs and the shaft in several different ways as will be described hereinafter. The discs, extend about the shaft for 360, but advantageously each disc can be composed of a plurality of segments with spacing between the adjacent ends of the segments allowing for free contraction and expansion of the discs relative to the shaft in a circumferential sense. 7

Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawings which, ,by way of illustration, show preferred embodiments of the present invention and the principles thereof and what I now consider to be the best mode in which I have contemplated applying those principles. Other embodiments of the invention embodying the same or equivalent principles may be used and structural changes may be made as desired by those skilled in theart without departing from the present invention and the purview of the appended claims. I

In the drawings:

Fig. 1 is a sectional view of a hopper to be mounted beneath a furnace of the kind mentioned above, and showing end views of a plurality of shafts having breaker discs thereon constructed and arranged in accordance with the present invention;

Figs. 2 and 3 are side views of the shafts shown in end elevation in Fig. 1 and further illustrating constructions .contemplated by the present invention;

Fig. 4 is a plan view of one form of breaker disc constructed in accordance with the present invention;

Fig. 5 is a sectional view taken substantially on the lineS-S of Fig. 4;

, Fig. 6 is a view taken substantially on the line 66 te en Fig. 7 is a sectional viewtaken substantially on the line 7--7 of Fig. 6; Fig. 8 is a plan view of a modified form of breaker disc constructed in accordance with the present invention;

Fig. 9 is a sectional view taken substantially on the line 99 of Fig. 8;

Fig. 10 is a sectional view taken on the line 1010 of Fig. 11;

Fig. 11 is a sectional view taken substantially on the line 11-11 of Fig. 10;

Fig. 12 is a plan view of another modified form of breaker disc constructed in accordance with the present invention; i I

Fig. '13 is a sectional view taken substantially on the line 13-13 of Fig. 12;

' ore material and the like charged in the furnace the'flow 'fThe breaker discs .D are advantageously arranged ;in rliiferent patterns on the "shafts to account for a .predematerial from the furnace (not shown)- being conveniently indicated by legend. It will be observed that a pair of hoppers H1 and EH2 are in a lower position in the area A and are-secured to a relatively large mount ing 4515:; 3( the arrangement being such that the lower discharge end of the hoppers are disposed'to funnel and discharge the material .passing through the thoppers -H1' tilTeriefoii oh tol'such conveyors -or the like, ;a plurality .of

ers

is s,'-,genera11y indicated at D in Fig. l -and to be demined, in greater 'de'tailfhereinafter, are ;:indiv idually own) and 'eachhliaftfas shown tinlFigs. 2 tand-.3, ;is o withanaidaligfoo've G in which fits a:k ey.ca rried' hytheidrivemean's for rotating the shafts-S. The discs D 'a1f'efpfrovidedwith'lteethiT, Fig. 1 as will be described,

' this mannemne rotating discs tend to crushand i rea'kilp 'largefchunks or the iii-flowing material ;-movingfromthe' furnace in the direction 'of thefhoppers H1 and tennind op,timum' cru'shiiig or breaking action. :Thus, referring 'tofFig's. 2 andi3, two off'the shafts S, indicated eff-S2 ands}, respectively, are so; constructed fthatthe 52 carries four discsjD 'whereas' meshes S3 Icarshafts S towhichtheyarejallocate V ln fu'rnaces -of' the'kind'under consideration, relatively high temperatures are developed such tha't'the inflow of 7 7 material'in the area A causes severe overheating of the shafts =8 and -then discs D. 'In order to'piolong the life oflthe shafts 8, it has previously been proposed 'to 'form "the 'shafts of 'a hollow construction to enable cooling 3'! the hoppers is properly broken up prior to deposit' in ed to 'the fshaft's spacedrelation soas -to;rotate' herewith. V The shafts S-aresupported byv bearings (not 'fc hnnk breakersha'fts S are arranged in two horizontal dve'the'disc'harge endsof the hoppers, and-break- '15 circumferentialiexpansiontandwontraction; and the empresent invention are primarily distin- 7 V om't'he'iotherbn'theihasis o f't'heiparticular manner lI'l'WhlCh the disc'sc'an be joinedto the shafts for rotationtherewith. 7 1 a a One enhodirient ofza lcfiisflfer or chunk .b'reaker disc constructed in accordance with thepresent invention is illustrated in Figs. Z 't'o Tinclusive'l "Thus, the disc 25, Figs. 4 and 5, is in the form of an'annular one-piece part cast from the alloy specified above or one closely lakin thereto. :The disci 25-has a solidcircumferential or annulai--=outer wall .-26"from whicheproject auplurality of integrally fcast,;teeth orgilugs 27 ;.of solid construction breaking '-el e:ment'swhich account for thedesirecl grindwater to be directed into the interior thereof as indicated by legend in Figs. 2 and 3.

In accordance with the presntinvention, the discs D,

all 'consist "of "a "heat resistant alloy of arelativel'y expensive nature in comparison to ordinary ferrous metal :alloys. Thus, discs of "the of thef'ollowing:

C ---0.10-0-.80 V Ni 5-30 Cr -'30 Mn Si =3%-max. Fe h e a --Balance 7 The alloy used for the discs'D'has(quite-different therpresent invention may be cast mal;.characteristics in comparison to stainless steel Fused for the shafts S which, as explained above, are tobe water-cooled. Hence it 7 becomes important, especially in, view of the initial cost of the alloy discs D, to prolong their life andto assure thatthere'will be no "cracking or warpage due to the association ofthe dis'cs-D with :the water-cooled-shafts S. In accordance with thep'resent invention, the discs D are configured andarran'ged to have as little peripheral contact as possible with the 6 tween the shafts S and the discs] D -to cause-the discs .D to rotate with the shafts-S. Three-diflerent'iembodi- {annular spaced-apart rims th'ere'by deducing" in 'the sfirst th'liiz'efthe .possible ereaeontaet between itherdiscs ED aiid'the relat'e'dshaft s. Additionally, the internal di-l throughout, the"tee'thr27 in cooperation with iiketeeth {OH =an :op'po'site shaft as S representing the grinding or "ing or breaking-action -on the -material flowing from the 5 furnace'into the'area A'and downward past the shafts ;as -S. 'I;{he=disc -iscast to -'havea pair of spaced-apart {side rwalls or flanges ;30 and-31 integral with and projecting-radially :inwardly from the outer circumferential wall26 ,;and these flanges terminate in fiat annular-rims EItlRandSlR which definethe inside diameter of each *disc-as 25.7 'ii' he "distance separating the outer surfaces .of the sidewallsiil and -3 1 is;nogreater than the maxi-. mm width each tooth' 2 7-,-ibut the side walls and their rims .3llR- and are of narrower axial *width ft'haniare thefteeth 27. {In fact the combined width-or Tthikness foil the .walls .30 and-31 is p less than that of a "tooth 27 and this accounts; forthe hollow nature of the Zdisc"2 5. 'a'hout its inside diameter. 7 I

' As shoWnT'in wFig.i5 itheurimsof' the disc 25am to concentrically 'sufrbund :the shaftfS but: are to be spaced Tslight'ly therefrom bylhavingthe rims of greater diameter ,than the outside fliameter of the related shaft S. In

order that each disc asf25 will rotate with the shaft S,

- jinitiimize the.transfertoflheatgbetween the .disc and the shafts. w I a H njassen'ibling the 'disesIZS voiithe shaft-S, shown'in 4 i 25v will be turned until'the'keyreceiving' 'recesssdftherein are aligned 'with the keys 35 on'the shaft sywhereupon each disc is slipped into fplace by beiiigfnoved' axially'along the shaft -S until its flzey-receivingjopen'ings,are related to those keys 35 which definethe'locatidn dflthe.partictilardiselS on theshaft S. :Asshownin Fig. 7, t'he 'keysSS are-securedin place by arguments, 1 i

,j'In o'rder'th'at each disc will be properly held in its {selected j aiialjpdsition on: the shaft S, retainer lugs 40 a gndf t'lfl-iigj, are welded to the outer end surfaces of :the keys 35 are: the related discs have been-assembled in propenp'ositio'n. :-lugs'40 and 41 are to be disposed opposite solid surfacespatjthe 'sides ":of the disc. As shbwnparticularly inF-ig; -7, itisrpreferable to have .spacing between the 1 opposedssurfaces fof such lu'gs I and theeside -walls 30":and 31iof=each disc 25, again contributing tofthe Eattainmentof c'as :littleeontact as possible be- :tween'vthediscss25i and parts directly' in 'c'ont'act with the 15 shaft s.

. Another form of the present invention is illustrated in breaker disc of annular form is-assembled from four segments 50-1, 50-2, 50-3, and 50-4, the relationship being such that when the segments are arranged end-toend to complete a 360 circle, the adjacent ends thereof are spaced slightly from one another as indicated at SP, and such spacing allows for circumferential expansion of the disc assembly 50 relative to the shaft S, Fig. 11, on which such discs are assembled in complemental seg- 'mental form. Each disc. segment, illustrated in Fig. 8,

is formed with a pair of solid teeth 53 and the inside diameter of each segment is hollowed to provide a spaced lpair of arcuate side walls or flanges 55 and 56 having rims 55R and 56R which represent the inside diameter of the assembled disc 50. As in the foregoing embodiment the side walls and their rims 55R and 56R are each of narrower axial dimension in comparison to the teeth 53, and in fact this istrue of the combined dimension of the rims accounting for the hollow internal construction to reduce the possible area contact between th disc 50 and its shaft S.

As in the instance of the disc 25, the disc 50- composed of the several segments mentioned above is to be so arranged on the shaft S as to have spacing between the outside diameter of the shaft S and the inner surfaces of the flanges 55 and 56.

In the instance of the disc 25, it will be realized tha the disc 25 has some play on the shaft S and that in the actual construction each disc 25 will have at least a point of contact with the shaft S. This contact is of no moment, however, insofar as the essential feature of the present invention is concerned which resides in having as little contact as possible between the discs and their shafts. Since, however, the disc 50 is not of one-piece construction, a shim of cardboard 60 or the like is fitted abo'ut'that portion of the shaft S where a disc 50 is to 'be mounted. Theindividual disc segments illustrated in Fig. 8 are then located one-by-one on the shim with the inner rim surfaces of the flanged side walls 55 and 56 in contact with the shim as shown in Figs. 10 and 11, whereupon spaced weldments of spot form, as shown in Fig. 10, are laid down to unite each segment directly to the shaft S as shown in Fig. 10 for rotation therewith. Because the weldments do establish a direct contact between the disc as 50 and its shaft S, such weldments should be held to the minimum necessary to procure a firm and sustainable union.

.Still a third form of the present invention is illustrated in Figs. 12 to 15, inclusive. This particular form of the invention in reality embodies some of the features or both of the two embodiments described above. Thus, the chunk breaker disc 70, shown in Fig. 12, is composed of individual segments, but instead of welding these segments directly to the shaft S in the manner described above in connection with Figs. 10 and 11, spacer bars 75, Figs. 14 and 15, are first interposed between the inside diameter of the disc 70, represented by the disc rims 76R and 77R, and the outside diameter of the shaft S on which the discs 70 are mounted to thereby account for a greater degree of radial spacing between the rims of the discs 70 and the related shaft S than is afforded by the modified form of the invention illustrated in Figs. 8 to 11.

Assuming that the teeth on the various different forms of breaker discs under the present invention are all to lie on a common circle, the disc at 70 can in factbe viewed as one wherein the radial dimensions of the side Walls 76 and 77 thereof are shortened in comparison to the side walls 55 and 56 of the disc 50. Thus, the side walls 76 and 77 of the disc 70 are of shorter radial dimension than the side walls 55 and 56 of the disc 50, and hence the inner diameter of the disc 70 defined by the radial inner surfaces, 76R and 77R of the side walls 76 and 77 are spaced radially outwardly of the outer diameter of the shaft S, Figs. 14 and 15, a greater distance than the corresponding spacing in Figs. 10 and 11. In the greater space thus established between the outside diameter of the shaft S and the inside diameter of the disc 70, a plurality of elongated rectangular steel spacer bars 75 are Welded at W to the outer diameter of the shaft S in spaced circumferential relation, and the dimension of the parts is such that the internal diameter of the rims afforded by the axially narrowed side walls of the disc 70 are to be radially spaced at ST from the outer surfaces of the spacer bar 75. This spacing can be established by using shims on the outer radial surfaces of the spacer bars in the manner described above.

As in the instance of the disc 50, each disc 70 is constructed from four segments, each having a pair of teeth 79 which are hollow inside diameter of each segment. The segments comprising the disc 70 are dimensioned to establish spacing SP2 between the adjacent ends thereof when the segments are properly assembled in a circle,

and as each segment is assembled about the related shaft S weldments W2 are deposited between the ends of the spacer bars 75 and the side walls of the segments to secure the latter to the spacer bars for rotation with the related shaft S.

It will be seen from the foregoing that in accordance with the present invention chunk breaker discs, cast from the heat-resistant alloy specified above or one closely akin thereof, are formed to embody spaced arcuate rims of less axial thickness than the thickness of the arcuate outer wall of the discand the teeth which project from the outer wall. Additionally, the rims of the discs are of larger inside diameter than the outside diameter of the steel shaft on which the discs are to be mounted, and this arrangement and configuration accounts in the first instance for as little contact as possible between the opposed surfaces of the discs and mounting surface of the shaft. In this way, the chances or likelihood of thermal warpage or cracking of the expensive heat-resistant discs, due to the difference in thermal co-efi'icients between the steel shaft and the discs, is reduced thereby minimizing maintenance problems. It is of course necessary to provide some sort of union between the shaft and the discs in order that the discs. will rotate with the shaft, and such union in accordance with the present invention is also of such order as to produce as little contact as possible between the discs and parts in direct contact with the shaft.

Hence, while I have illustrated and described preferred embodiments of my invention it is to be understood that these are capable of variation and modification, and I therefore do not wish to be limited to the precise details set forth, but desire to avail myself of such changes and alterations as fall within the purview of the following claims.

I claim:

1. In a chunk breaker to be installed adjacent a furnace for breaking up hot chunks of material discharged from the furnace, a cylindrical supporting shaft adapted to be rotated and cooled internally by means of a fluid cooling stream, said shaft being composed of ferrous material having a given coefficient of thermal expansion, and a breaker disc mounted on said shaft and extending circumferentially thereabout for rotation therewith, said disc being composed of a heat-resistant ferrous metal alloy having a coefficient of thermal expansion difierent from that of said shaft, said disc having spaced teeth of uniform dimension formed on the outer periphery thereof and having an arcuate inner peripheral rim of narrower axial dimension than said teeth and of greater diameter than the outside diameter of said shaft, and means contacting the outer surface of the shaft at circumferentially spaced points and securing the disc to the outer periphery of said shaft with spacing between the arcuate inner surface of said rim and the outer surface of said shaft.

2. In a chunk breaker to be installed adjacent a fur- 7 having; a pair of js'p'aced a'part innerfp e is A e nac'ef'for bre'aldngriup hot chunks of materialiliseharged fron'1 the furnjace,- a supporting shaftalapted l'O jbe' l'O- jtatea and cooled i'internally by mean ot a fluiq eepling stream; said shaft Bein c'o'm'pose'd of ferrous mate-rial :hreakerdisc mounted Unsaid shaftffor -rotation therewith, said disc bein'geomp'os'ed of a heat-resistantfer rous "metal alloy having a cOefiicient-of thermal expansion diffferentf'from that of said shaft,"s'aid'dZschaying spaced :feethfo'rmed'on the outer periphery thereofland having [an innerperipheralarcuate rim of n'arrower axialfdim'ensio'n than 'said teeth, 'andhie'ans contacting the outer'sur- V face'of'the shaft at acir'curnfe'rentially spaced points-and ,s e'curingthedisc to the ohterlperiphery of 'saildSh'aft with V spacing between the arcuate inner surface of said rim aiifdftheouter surface of said shaft. 7 V V a 3. "-In chunk breaker to betnstalleh ,adjaeentatur- "nice 'for breaking up hot l'cliuriks, of ematerial-di'seharged iirointhe furnace, va cylindrical supportingishaftfadajite'd to be rotated and {cooled internally by means .6 poolin stream, jsaid shaft being .composedllofl ferrous ,mat'er-ialha'ving a given,coefiieientof'thermalex ansion,

and a breaker disc mountedon' said s'hzifti'for rotation therewith, said disc being composed of a heatr'esista'nt ferrous, metjali'alloy having a "coefficient "of th e'r'rnal ex- ,Iiansion' different from that of saidfsha' fhf said discfhaying jsp'aced teeth formed on the outer 'pe'rip'hery "thereof, and i phe'ral .arcuate "rims each of narrower 'axi'al dimension'j 'shafLand means contacting the outerjsu'r'faceofthe shaft fiat circumferentially spaced .p'oin'ts and secufrin'gjthe disc it'othe Outer periphery of said sha'ft'with spacing between the arcuate innersurfa'ce ofsaid rim and the -oute'r 'surface of saidsh'aft. U V V 4.7A chunk 'breaker according to claimj'3-where'in the 'disc is weldedjat s'pacedjpoin'ts itotheou'ter surface of V I an said teeth; and of ia'r'g'er diameterthan the outer'l iiam'eterbf said 7 7; Ag-chunk breaker accordinglto. iwherein :spac'er -barsesecured tojhe outer surface: of 4 the shaft "are interposed between the rims oi the ,disdand the outer surface of the shaft;

' j k disc d'a ted tohe m'ountetdjon a'fshaft to afiord 1a :jchunk' breaker shaft and cqmp'rjising.anjarcuatej outer iwall haying aplurality of radially projecting 'teethformefl thereon "in "a single -1 oW and 'in circumferential "spaced relation, said" teeth each having a givenajl thickness and-a given radialfprojecting 'dimensi'on, "'an'd3said disc being formed withfspaced substantially parallel arcu'at'e side xwalls 'afi ordingspaced ar cu'at'e inner rims which are concentric to said ar'cua'te outenwa'llgsaid rims each being pf less axial thickness thanfthe; individual axial fihickness *ojtlsaid'teeth." 1 a I lj '9.;In a chunksbrealcerfto be installed'adja'cenfa'furnace for breaking up hot chunks o'f rnater'ial emitting "from the furnace, a supporting shaft adapted tofbe rotatedand cooled internally bymjeans of "a 'fiuid qco'oling streamgand a plurality of breaker discs mounted thereon ffor-rotation therewith, said 'discs e'ach having spaced teeth iorrned' in but a single circumferential row aboutfth'e :outer periphery -thereo ffandeach having an jinnerfperiph- \erai rirnfoff narrower axial :dim'ension than fsaid'teeth, and-'means securing ea'ch disctoi the quter periphery "of "said shaft to :provide heafibarrier sp'ac'in'g b e'tw'een the arcuate inner surface of each rim and the outer surface of said shaftfsaid securingnieans contacting thje 'outer s'urfa'ce of the shaft discontinuously" atfwidely spaced points circurnferentiallyabout 'the outer surface of; said sha'f'tand contacting e'ach' of said -'disc s'fdiscontinuously i t "atW dely" c i ts-

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