US1728750A - Rotary-hearth furnace - Google Patents

Description

Se'pt. 17, 1929. E. s. FATKIN ROTARY HEARTH FURNACE Filed Sept. 19, 1927 2 Sheets-Sheet /w/ 4,/ l f INVENTOR Edward SFmkin.

Sept. 17, 1929. E. s. FATKIN ROTARY HEARTH FURNACE Filed Sept. 19. 1927 2 Sheets-Sheet IVENTOR n Edward SFcJTk n.

ATTRNEY Patented Sept. 17, 1929 UNITED STATES PATENT, oF/FICEN MANUFACTURING COMPANY, A CORPORATION OF llllNNSYL,TANIA no'rARY-HEARrH FURNAGE l f f Application filed September 19, 1927-. `Serial Nc. 220,536.`

My invention relates to furnacesand more particularly to furnaces of the tiltable-hearthtray type.

In furnaces of the above-mentioned type, difficulty has beenexperienced in providing means for pivotally mounting the hearth tray? which will not bind or stick when subjected to heating and cooling of the parts incidentto operation of the furnace.y

It is an object ofmy invention, therefore, to provide an improved means for mounting a hearth tray which permits the free pivotal movement thereof during "the operationqoff` the furnace and which is sufficiently rugged in construction to withstand the `relatively high furnace-chamber temperature.

In practicing my invention, I provide, in a rotary-hearth furnace having a plurality of hearth trays therein for containing the material to be heat-treated, means for ,pivotally mounting said trays upon said hearth comprising a plurality of cupped bearing surfaces adapted to cooperate with convex bearing surfaces formed on said trays and means for preventing relative longitudinal and vertical movement between said bearing surfaces.

In the drawings,

Figure 1 is a view, in vertical section, of a rotary-hearth furnace embodying my invention,

Fig. 2 is a plan view, partially broken away, of a tray-supporting means embodying my invention,

Fig. 8 is a section talivon the line III-III i of Fig. 2,

Fig. 4 is a lateral i elevation of the hearth tray embodying my invention, and

Fig. 5 is a bottom plan view of a hearth tray shown in Fig. 4.

Referring more particularly to the drawings, a furnace embodying my invention comprises annular walls and roof portions built up of suitable refractory heat-insulating ma terial dening an annular furnace chamber,

and provided, for structural reasons, with a sheet-metal shell 2 and the usual structural reinforcing irons 4.

A chute 5 for facilitating the discharge of material from said furnace chamber projects through the outer wall of the furnace and is adapted to ycommunicate withy a'quench tank,

or c0nveyor, l(not shown) yin theusual manner. i y An annular opening isy formed in the bottom of the furnace chamber for the reception of an annular hearth 6, carried upon an annular metallic structure 8which is mounted for movement through thefurnace chamber upon flanged' Wheels 10 cooperating with' a circular rail 12 secured to the furnace foundation. n

Sand-seals 14 and 16, of the usual type,fare provided between the annular edges ofthe hearthand the opening in the floor of the fur# nacechamber. f j i Rotation of the hearth is effected by an elec* tric motor 18 operatively connected, through suitable gearing 20,`-to avertical shaft 22 eX-` tending axially of the furnace chamber and hearth. A bevel gear 24, secured tot-he lower end ofthe shaft22, engages a bevely gear 26 suitably secured to a shaft 28 to yrotate'agear 30, secured thereto. `The gearBOcooperates with an annular gear rack 32 secured` to the hearth structure t8 to effect the rotation thereof. f f

f 'Uponthe hearth x6 are pivotally mounted ya plurality of article-carrying :hearth trays 40 to be successively tilted to effect the discharge of material therefrom through saiddischarge chutef.` s L, Thetiltingof trays 40fis effected by a lifting rod 42 provided, at `the lower end there-4 of, with suitable means forengagingsaid trays and provided, atthe .upper`r end thereof, with a lateral projection 43 adapted yto ride in ascontinuousr cam slot formed in the face of a drum 44, the frotation of which is caused by a motor 46operatively connected z` thereto. y s

VThe `structure above described constitutes a tiltable-tray, rotary-hearth furnace off-the usual type and, since the specific details of:

construction thereof form nofpart of the pres- I ent invention, `a more 2 detailed thereofls not deemed necessary. l f s My inventionlcontemplates,fmore specificaldescription ly, the provision of an improved-lpivotal erein- 4 mountingfor .the hearth trays r40, `as after described in detail.

Spaced circumferentially on the upper face of hearth 6 are a plurality of supporting structures indicated broadly as 50. The base of each supporting structure is channeled, as at 51, to receive a projecting portion 52 formed on the refractory hearth to maintain the hearth and support it in fixed relation. The Vchannel is somewhat larger in width than the projecting portion 52 ofthe hearth to permit relative, contraction and expansion therebetween. 4 j

Adjacent Vtothe outer edge of the supporting structure, is a pair of bearing faces 54., substantially semi-circular in lateral section, spaced above the base of the supporting structure and having the axes thereof in aline-y men-t and substantially"v perpendicular fito ak hearth radius passi-ngv therebetween.

Peripherally of the support along the inner lateral edge and sides thereof is formed l' a substantially vertical wall 56'fer supporting the hearth tray in operative horizontal position, as hereinafter described.

Extending upwardly from the supporting base, onthe lateral sides of the bearingl surfaces, are apertured walls 58 which co"- i CO of curvatureof the bearing surfaces by permitting tilting of the trays.r telativey r Byk my invention, I haveprovided a pivotal operate with the bearing surfaces to form substantially semi-cyliiidrical recesses.

The hearth trays LO- comprise substantially segmentshaped containers open at the lateral edges thereof adjacent tothe outer wall of the furnace.

Depending from the bottom of each tray are two apertured lugs 62 havingvrounded or convexbearing surfaces formed on lthe lower ends thereof andv adapted to fit into the recesses or concave bearing surfaces 54 formed between the plates 58,' with the aper-f` tures .in the lugs and plates in horizontalalinement.

A rod or pin 64; of suitable heateresistant material is adapted to cooperate with said apertures tofma'intain the support Vand the tray in operative relation. Theapertures in the lugs and plates are coaxialwiththe rsltldiu's t erelateral movement between the trays andthe supports is prevented by the -cooperating plates 58, and the bearingjsurfaces are maintained in operative relation by the bar64.

With the structure described,-it is obvious that the weight of the trayis substantially all carried by the interfitt-ing concave andcon-l vex bearingsurfaces formed on the support and tray, respectively, and since the effect of the heat, incident to furnace operation, will aifectboth surfaces equally, the pivotal movement of the tray will not be aEected. "On the other hand, ifthe usual type of pivoted or hinged supporting means with the weight carried by a hinge pin, is employed7 the high temperature will result inl excessive wear of the hinge elements.

mounting for a tiltable hearth tray which is efficient and effective in operation at furnacechamber temperatures.y Obviously, although I have described a furnace of a specic type, my invention is not limited in its application, thereto, but is applicable in any connection where a hinge jont may be subjected to excessive heat, as in a furnace chamber.

Various modifications may be made in my invention without departing from the spirit and scopev thereof, and I desire, therefore, that only such limitations shall be placed thereon as are, imposed by the prior art and set forth in the appended claims.

I claim as my invention:

l. In a bearing for pivotally mounting a hearth tray,'forcontaining materials during the heat treatment thereof ina furnace.

chamber, comprising a stationary support, a concave bearing surface formed in said suport, a support for said tray having a convex 1 earing surface formed thereon, and means formaintaining said bearing surfaces in cooperative relation.

2. In a bearing for pivotally mounting a hearth tray, for containing materials dur ing the hea-t treatment thereof in a furnace chamber, comprising a support, spaced concave bearing surfaces formed in said support, a tray, spaced lugs on said tray hav- 9... ing convex bearing surfaces formed at the Jen iso

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