US 2940745 A
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Description (OCR text may contain errors)
June 14, 1960 P, w. GRIEGER ETAL 2,940,745
SUPPORTING MEANS FOR VFURNACE CHARGES WGr lim v l@ Y .F
United States Patent O SUPPORTING MEANS FOR FURNACE CHARGES Paul W. Grieger and Edward I. McCabe, Pittsfield, Mass., assignors to General Electric Company, a corporation of New York Filed Oct. 1S, 1956, Ser. No. 616,810
1 Claim. (Cl. 263-47) The present invention relates to supporting apparatus, and more particularly to apparatus for supporting material while being heated in an annealing furnace or the like. The invention has particular application to large furnaces of the type having a hearth or floor mounted on a movable support such as a car which is arranged to carry a large quantity of material such as stacks or coils of steel sheets and adapted to be moved or lifted into and withdrawn from the furnace.
Furnace cars of the above type areshown and described in U.S. Patent 1,963,846, lpsen et al. As there illustrated, the furnace car is provided with spaced support columns secured to the car oor and having hearth plates on their upper ends on which the charge of stacked sheets is supported while being heated.
Support structures of this type are subject to certain drawbacks. Due to the elevated furnace temperatures to which the apparatus is subjected, the hearth plates which bridge the supporting columns expand a substantial amount and cause the upper portion of the support posts to deliect laterally. The weight of the load itself aggravates such deflection when the posts have become bent beyond a certain point. As a result, the posts soon become deformed to an extent where they will no longer uniformly support the loads or will allow dangerous tilting of the stacked sheets. It then becomes necessary to remove theinsulating material usually provided on the car between the posts, unbolt the posts at their base or burn them off if welded, re-secure the new posts to the car oor, and replace the insulation material. Such operations, particularly in view of the large number of posts involved, require considerable time, labor and eX- pense and further loss is occasioned in the shutdown of the furnace while the car is being repaired.
It is an object of the present invention to provide an improved furnace charge supporting device of the above type which overcomes the disadvantage of the known supporting apparatus.
lt is another object of the invention to provide an improved supporting post structure for support apparatus of the above type which has longer operational life under elevated furnace temperature and considerably facilitates repair or renewal of the supporting posts.
In accordance with the invention, there is provided a supporting device for furnace charges which comprise the combination of a supporting base, and a plurality of composite posts mounted on the supporting base and adapted to carry material to be heated in a furnace, each composite post comprising a lower post portion secured to the supporting base and an upper post portion on which the material to be heated is adapted to be carried, the upper post portion being removably mounted on the lower post portion. Normally, a hearth oor comprising one or more metal plates bridging the tops of the upper post portions is provided for carrying the charge load. Preferably, the upper post portions are of tubular form and are rotatable on the lower post portions so that after the upper post portions have undergone appreciable lateral deflection or deformation due to the expansion of the heated metal material or hearth plates resting thereon, they may be rotated to compensate for further deection caused by continued use in the furnace. It is preferred, in accordance with the invention to provide a tubular insert member projecting upwardly from the lower post portion on which the upper post portion is positioned.
The invention will be better understood from the following description taken in conjunction with the accomf panying drawing, in which:
Fig. 1 is an elevational view of a furnace provided with a furnace car embodying the present invention;
Fig. 2 is a fragmentary view in elevation of the side of the furnace car;
Fig. 3 is a sectional view in elevation of the post of the present invention showing constructional details; and
Fig; 4 is a cross-section of the post shown in FiU. 3 taken along the line 4-4.
Referring now to the drawing, and particularly to Fig. l, there is shown an elevator-type annealing furnace 1 having heating units 2 along its walls and an opening 3 at the bottom through which the furnace car 4 may pass when raised vertically to position the load 5 of steel strips or the like within the furnace interior. The charge 5 of metal strips rests upon hearth plates 8 supported on posts 7, and when car 4 is raised interoperativc position, hearth plates S serve as the floor ofthe furnace. A suitable elevator mechanism 6 may be used for raising and lowering car 4, which in the lowered position is adapted to run on tracks 16. lt will be u nderstood, however, that types of furnaces and supporting platforms other than those shown may suitably embody the support post device of the present invention.
Fig. 2 shows in greater detail the arrangement of support posts 7 on car 4, with the posts 7 carrying one or more hearth plates 8 on which rest the stacked sheets of steel 5. As many as 60 support posts 7 may be mounted on the car uniformly spaced from each other and with the weight of load 5 distributed over them as uniformly as possible. Hearth plates 8 may be of such length as to bridge two or more posts on the car, and form a at supporting surface for suitably distributing the weight of the charge on the posts. Suitable heatinsulating material 9 such as finely divided diatomaceous earth, fire brick, or the like preferably is placed on the car bed to ll the spaces between posts 7 to a substantial level, normally as high as the car walls to protect the lower portions of the posts and the car oor from the intense heat of the furnace and in order to avoid absorption of the furnace heat by these parts.
Due to the extremely elevated temperature (e.g.; 1100 C.) to which the charge 5, hearth plates S, and the upper portions of posts 7 are subjected in the furnace, considerable difficulty has resulted in the past from the lateral deection or deformation of the support posts of the type heretofore used, principally caused by the thermal expansion of the hearthV plates 8. This deformation was aggravated by the heavy load imposed on the posts and the extreme heat which tended to weaken the posts.
The improved structure of support posts 7 in accordance with the invention as shown in detail in Figs. 3 and 4 has overcome the foregoing diiculty to a remarkable degree. As shown in Fig. 3, a preferred construction comprises a tubular base 10 of heavy steel which may be welded to or otherwise rmly secured to the car bed or other supporting platform. Inserted into and welded on base 19 is a post member 11 which extends upwardly from base I10 and together therewith constitutes the lower, fixed portion of the present composite post device. Member 11 is preferably composed of a obvious that a single Vtubular member high Vtemperature resistant nickel-chrome alloy steeI of Y known composition. While two members and 11u are Y Y rests freely with a substantial portion of its length pro Y jecting upwardly beyond the top of member 11. @Upper post member 14,' also preferably composed of Vhigh-temperature alloy material, is located directly over and in abutting relation with the lower member 111 and impaled over the projecting portion of insert member 13.v
As shown, lower and upper post members 1-'1 and 14 are of' about the sameV wall thickness and-diameter, whereastubular insert member 13 has an outside diam'- eter somewhat less than the inside diameters of members 11 Vand 14 so as to provide appreciable clearance e Vbetween itself and thepost members. Normally, the
clearance between members 11, 14 and insert member 13 is less than the wall thickness ofthe post members.'
While apreferred arrangement of the post components is illustratedV in theVV drawing, it will be understood that arrangements Othenthan that shown could be usedl if l desired'V and would come the scope of the inven For example, the -inser't member I3 could be long enough to rest on the'rcar bed,rather than being mount-V edjonfthe lower member llas shown, or it may form an integral part of member 211,V rather thanV beingV sep f arablyj'mountedthereon. Further,V the Vupperand lower postlmembers could' be of diierentdiameters and have flange means Vor the like at their adjacent ends to provide, a suitable supporting surface therebetween.
` ,"Thou'gh'n'ot essential tothe present invention, the
,tween upper and lower'post members inorder to prevent the particula'ted heat'insul'ating material 9'surroun'ding :the post units fromL gaining vaccess through thejoint tothe spacesbetween` thepost parts and thereby hindering movementVV therebetween. The insulating material 9 mayV also be placed within vthe hollow post units, so long as care is- `taken to avoid the presence of the insulatingmateri'al in the space between insert member 13 and the members v11, 14.
The clearance between upper post member'14 and Vinsert member 13 permits lateral movement of member described postA assembly may be supplemented with-an outer'sleeve 15 which is arranged covering the joint be- Y 4 Y occurs much sooner than deterioration. 'Furthermore by virtue. of the present invention, when the4 posts.. are no longer suitable for the ,annealing process, only the upper members need be removed Yand replaced by new ones. The same procedure may be employed with insert member .13 if this needs replacement, since this understood that numerous modifications mayV be madeV by those skilled in the art Without actuallyrrdeparting from the scope of the invention. Therefore, theappended Vclaim is intended to cover all such equivalent variations asc'omerwithin Vthe true spirit and scopeof the invention. What we claimY as new'and desire to secure by Letters Patentof the YUnited States is: Y
A supporting device Vfor furnace-charges comprising, in combination, a supporting-base, a plurality of' composite posts mounted vonsaid'vsupporting base and adapted Vto support material to bel heated 'in affurnace, each said composite post comprising Ya lower` tubularv post portion xedly secured to said supporting base, a cylindrical insertmembermounted within saidrlower tubular post portion andprojectingupwardly therefrom, an upper tubufy lar post portion having a; thickness `about the same as that of said lowery post portion separablyand rotatably mounted in abutting relation on said lowerpost ,portion and impaled on said kcylindrical insert member, the clearance between said insert'member and said post portionsbeingless than the thickness of said post portions,
' the top of# said; upper postY portion being above said in- 14 Vin response tothe thermal expansion of the loaded hearth plate 8 restingl on top of Vmember 14, and such limited shifting thus compensates for part of the thermal Y expansion of hearth plate 8 before it causes deflection orf-deformation of any part of theV post structure. Once deformation of the upper post member begins, as observed Yafter the annealing treatment, it is necessary only inaccordanc'eV with the invention, to rotate upper post memberV 14 Ythrough an angle `of 180y about its axis before the next furnace treatment. By such rotation, member V14Y isinarposition whereby the hearth plate expanlforces tend to return it to its former vertical position. With the postl deection thus cancelled out, the
posts need be replaced only because of deterioration by aging and not Vbecause of deformation, which normally sert member, Vpartieulated heat-'insulating1material on said supportingl base occupying-the space between said composite posts lto a predetermined level above said lower post portion, the separation'ofV said upper and lower post portions being substantially closer to said predeterminedV level than to the supporting base, an outer tubular member arrangedV about each composite post Y covering the abutting joint of said upper and lower post portions, saidV upper post portion being readily upwardly removable away from said lower post portion and'out of said outer tubular member and said heat insulating material and metal plate meansresting on and extend- `ing acrossV the top of said upperV post portions and forming thereon av supporting surface bridging the tops of saidV composite posts. Y
References-Cited in the le of this patent UNITED STATES PATENTS Moore et a1. Dec. 11, 1928 1,963,846 Ipsen et al. June 19, 1934 2,056,522 Hunter et al. Oct. 6, 1936 2,138,321 Bratasianu Nov. 29, 1938 2,837,326