US2849219A

US2849219A - Furnace bottom supports

Info

Publication number: US2849219A
Application number: US554075A
Authority: US
Inventors: Frank J Boron
Original assignee: American Brake Shoe Co
Current assignee: American Brake Shoe Co
Priority date: 1955-12-19
Filing date: 1955-12-19
Publication date: 1958-08-26
Anticipated expiration: 1975-08-26

Description

Aug- 26, 1958 F. J. BORON 2,849,219

FURNAOE BOTTOM SUPPORTS Filed Deo. 19, 1955 v 2 sheets-sheet 1 IHIHIIIHHHH "Illlll Inn/enfer A vcfan/(Joran w4orneys Aug. 26, 1958 F. J. BORQN 2,849,219

FURNACE BOTTOM SUPPORTS Filed Dec. 19, 1955 2 Sheets-Sheet 2 vfzarneys 2,849,219 Patented Aug. 26, 1958 FURNACE BOTTOM SUPPORTS Frank J. Boron, Elyria, Ohio, assignori-to American Brake Shoe Company, New York, N. Y., a Vcorporation of Delaware Appucation December 19, 195s, serial No. 554,075

4 Claims. (Crees- 40) This invention relates to work-container supports for heat treating furnaces of the well known forced convection type, i l

In many furnaces of the foregoing kind, a fan or such forced draft means is mounted at the v.bottom of the furnace beneath the basket or work-container carrying the work to be heated, so that the furnace atmosphere is forcibly directed upwardly through and about the workcontainer to heat the work. It has been proposed to dispose between such forced draft means and the workcontainer a so-called bottom support on which the container is rested and which affords a housing in which the forced draft means operates beneath the vlower open end of the work-container. Such bottom support has `been furnished ,in the form of a one-piece part, either a unitary casting or segments that are welded to alford a full circle bottom support, and V4it ,has been `found that these have a relatively short life due Yto the `rathergsevere thermal expansions thatare encountered.

The primary vobject .of ,the present invention ,is Ato increase .the life `of the bottom support of a [furnace by constructing the bottom l,support of two complement-al half castings connected ins-uch a waythat these comple- .mental parts .can yexpand and .contract freely, ,and ,to Vfacilitate this by assuring that certain connecting joints `between the Ahalf lcastings do not carry `any of' the load of the Work container. Specifically, the object of the `invention `is .to provide `ears at the opposed ends ofthe halficastings .that Vafford loose -joint connections .between the half castings so as to unite these while ,allo-wing thermal `expansion `or creep to occur freely.

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 Ya preferred .embodiment of the present `invention `and the principles .thereof .and what l now consider to be .the best Vmode in which I `have contemplated applying thatvprinciple.. .Other ernbodiments of the invention ,embodying the same `orequivalent principles may be used :and structural .changes may be made as desired by `those skilled inthe art without departing from the present invention and the .purview of 'the appended claims.

in the drawings:

Fig. 1 is a top plan view of a furnace bottom support constructed inV accordance with the present invention;

Fig. 2 is-a sectional view taken substantially on the line 2 2, of Fig. l;

Fig. 3 is atop plan view'of a :half casting; and

Fig. `4 is a side elevation of the half casting sho-wn in Fig. 3.

The present invention is illustrated in Fig. 1 as embodied in-a furnace bottom support l that ycomprises two complemental half castings `A'and 10B Awhich -at opposite ends are connected together so las -to `compensate for thermal expansion in `a way Vto be .described more specifically hereinbelow.

The bottom support in the present instance is adapted to .be used in Va heat treating furnace such as the kind illustrated .in U. S. Patent No. 2,686,665, so that the furnace bottom support 10 comprises a work-container support defined in part in the presentV instance by an upper wall or flange afforded by complemental 180 half-circle wall segments 12A .and ,12B corresponding to the

respective half castings

10A and 10B. lt will be observed in Fig. 1 that the fully complemented upper Wall thus afforded defines an opening 15 of relatively large diameter, but of somewhat smaller diameter than the bottom of the work-container or basket that is adapted to be supported by the complemental upper Wall segments MA and 12B.

Spaced from the upper wall of the bottom support 10 `is an annular vor full-circle lower wall defined by complemental 180 half

circle wall segments

18A and 18B.

The

wall segments

12A, 18A and 12B, 18B are integrally united by corresponding half-circle vertical web sections 20A and 20B so as to provide a chamberv for gases below the work-container.

The lower Vwall afforded by the

wall segments

18A and 18B extends radially inwardly of the opening 15 in Vthe upper wall, and the rounded inner edges thereof form a lower wall opening 23 which is of substantially less diameter than the diameter of a fan that is adapted to be mounted below the lower wall. Preferably, reinforcing ribs `25 are cast integral with the half castings so as to extend between the respective upper and lower wall segments as shown in Fig. 2.

-'In the furnace, a fan is arranged below the bottom support 10 with the shaft thereof directed upwardly so 'that the .fan blades rotate in a horizontal path beneath `the Ylower

wall segments

18A and 18B. The fan thus rotates within a housing or chamber aiforded vby four helically disposed vanes as 26, there being two such vanes dependent from the respectivehalf castings 10A andlilB in regular circumferential spacing. The vanes are cast integral with the two Vhalf castings so as to depend from the respective

lower Walls

18A and 18B. In `this connection, it will be observed that the arrangement of the vanes is such that the inner ends 27, Figs. 1 and 2, terminate `at points on the circumference of the opening '15 vin the'upper Wall of the bottom support, 'and 'flare out- Wardly on diverging arcs so that the outer ends '28 thereof are radially outwardly of the respective webs 20A and 20B. The inner ends 27 of the vanes 26 `are on a circle that is somewhat larger than the path of the fan blades, and the lower edges 30 of the respective vanes are adapted to serve as standards reposing on the upper face of a base member of the furnace such as illustrated inthe aforesaid patent.

It tis advantageous to prevent debris or particles of the'material undergoing heat treatment from entering the circular fan housing afforded by the vanes V26, and to this end gusset-like guards 33 and '34 `are provided so las to extend horizontally between the webs 20A and 20B and the upper edges of the vanes v26 that are outwardly of the webs 20A and 20B as shown kparticularly in Fig. 1. To assist in centering the work container on the flange or upper wall of the work support 10, vertical lugs 35 are provided outwardly of the webs 20A and 20B. These are preferably located at points -where the

guards

33 and 34 are joined to the webs 20A and 20B.

As shown in Fig. 1, there is substantial `circumferential spacing vbetween the outer edge 28 of one vane and the inner edge 27 of the next adjacent vane, and it will be further observed that the respective ends of the half castings terminate at two such areas, which is to say that other half casting extends somewhat rearwardly beyond the inner end 27 of its associated vane 26. The half casting thus having the end portion extended forwardly beyond the outer end of the associated vane is provided with an ear 40 which, as shown particularly in Figs. 2 and 4, is off-set upwardly and then forwardly in a horizontal plane so as to overlap and rest on the flat, free end portion 41, Fig. 2, of the adjacent half casting. Such constitutes an expandable joint, and normally there is slight spacing between the

respective ends

43 and 44 of the two half castings as shown in Fig. 1.

To connect loosely the half castings together so that the ears 40 provided on opposed ends of the respective half castings overlap the free end portion as 41 of the adjacent half casting, off set ears are also afforded on the webs A and 20B. Thus, as shown particularly in Figs. l and 3, ears 46 are off set radially outwardly and then forwardly from ends of the webs 20A and 20B corresponding to the ears 40, and the arrangement is such that these ears 46 overlap the at, free end portion of the adjacent end of the opposite web 20A or 20B. In the present instance, pairs of fastening bolts as 47 having associated nuts and washers are passed through pairs of aligned openings in each ear 46 and the portion of the web of the opposite half casting that is behind the ear 46. Such openings are indicated at 50 in the ears 46, Figs. 3 and 4 and at 51 at the opposite, flat end of the web 20A, and are slightly larger in diameter than the shank of the bolts so that the half castings are enabled to creep or expand thermally to the full extent as defined by the predetermined spacing between the

aforesaid ends

43 and 44 of the half castings.

Of particular importance in the present instance is that the ears 40 are provided at areas where there is circumferential spacing between the adjacent ends of adjacent webs 26 as was mentioned above. This assures that the joint afforded by the ear 40 and the underlying flat end portion of the lower wall segment of the opposite half-casting does not carry any of the load that is carried by the vanes 26 reposing on the support of the bottom of the furnace as was mentioned above. This particular arrangement frees the ears 40 of any vertical thrust so that thermal expansion occurs without resistance.

Hence, while I have illustrated and described the preferred embodiment of my invention, it is to -be understood that this is 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 bottom support for a furnace having adjacent its base a fan for forcibly circulating heated gases upwardly through and about an open-bottomed work-container in the furnace, two 180 complemental half castings adapted to be connected at ends thereof to provide a fan housing and a support for said container, each such casting comprising, a half-circle upper wally segment so that when the castings are connected such segments cooperate at their respective ends to afford a full-circle upper wall having an opening therein and on which said container is adapted to be supported over said opening, a half-circle lower wall segment so that when the castings are connected such lower wall segments cooperate at their respective ends to afford a full circle lower wall having an opening therein, said lower wall segments being joined to their respective upper wall segments by vertical spacing webs thereby affording an intervening chamber for circulation of gas below the bottom of said container, an ear off-set vertically and then forwardly at selected opposed ends of the lower wall segments of said half castings so as to overlap adjacent flat end portions of the lower wall segments with spacing between such opposing ends of the lower wall segments allowing for thermal expansion, spaced vanes depending from each lower wall segment so as to define a 360 fan housing and afford a standard for said bottom support in the furnace, said vanes diverging from their inner ends radially outwardly and terminating in outer ends disposed outwardly of said webs, the ends of the lower wall segments having ears and the ends of the lower wall segments having flat portions being located between the inner and outer ends of immediately adjacent vanes so that the ears and said overlapped flat portions carry none of the load of the work-container and are free to allow expansion as aforesaid, an ear olf-set radially and then forwardly from selected opposed ends of the Webs in said half castings so as to overlap an adjacent at end portion of the webs, and means loosely connecting each radially olf-set ear and the overlapped web portion corresponding thereto.

2. In a `bottom support for a furnace having adjacent its base a fan for forcibly circulating heated gases upwardly through and about an open-bottomed work-container in the furnace, two 180 complemental half castings adapted to be connected at ends thereof to provide a fan housing and a support for said container and each comprising, a half-circle upper wall segment so that when the two castings are connected such upper wall segments cooperate at their respective ends to afford a full-circle upper wall having an opening therein and on which said container is adapted to lbe supported over said opening, a half circle lower wall segment so that when the castings are connected such lower wall segments cooperate at their respective ends to afford a full circle lower wall having an opening therein, said lower wall segments ybeing joined to their respective upper wall segments by vertical spacing webs thereby affording an intervening chamber for circulation of gas below the bottom of said container, an ear off-set vertically and forwardly at selected ends of the lower Wall segments of said half castings so as to overlap adjacent flat end portions of the lower wall segments with spacing normally between such opposing ends of the lower wall segments allowing for thermal expansion, spaced vanes depending from each lower wall segment so as to dene a fan housing and afford a standard for said bottom support in the furnace, said vanes having inner ends inwardly of said webs and outer ends disposed outwardly of said Webs, the ends of the lower wall segments having ears and the ends of the lower wall segments having fiat portions being located lbetween the respective inner and outer ends of a pair of immediately adjacent vanes so that the ears and said flat portions carry none of the loadv of the work-container and are free to allow expansion as aforesaid, and means loosely connecting said castings at ends thereof.

3. In a bottom support for a furnace having adjacent its base means for forcibly circulating heated gases upwardly through an open-bottomed work-container in the furnace, two complemental half castings adapted to be connected at ends thereof to provide a chamber for such gases below the work-container and a support for said container above said chamber, each such casting comprising, an upper Wall half segment so that when the castings are connected such segments cooperate at their respective ends to afford `a fully complemented upper wall on which said container is adapted to be supported, a lower wall half segment so that when the castings are connected such lower wall segments cooperate at their respective ends to afford a fully complemented lower Wall, said lower Wall segments being joined to their respective upper wall segments thereby affording an intervening chamber for circulation of gas below the bottom of said container, an ear off-set vertically and then forwardly at selected ends of the lower wall segments of said half casting so yas to overlap adjacent flat end portions of the lower wall segments with spacing between such opposing ends of the lower wall segments allowing for thermal eXpansion, and means depending from each lower wall segment so as to afford a standard for said bottom support in the rateale 5 furnace except at the aforesaid opposing ends so that said ears and the associated overlapped portions do not carry any of the load of said work-container- 4. In a bottom support for a furnace having adjacent its base means for forcibly circulating heated gases upwardly through and about an open-bottomed work-container in the furnace, two complemental half castings,v

adapted to be connected at ends thereof to provide a chamber for such gases below the work-container and a support for said container above said chamber, each such casting comprising, an upper Wall half segment so that of gas below the bottom of said container, an ear off-set i vertically and then forwardly at selected ends of the lower wall segments of said half castings so as to overlap adjacent at end portions of the lower wall segments with spacing between such opposing ends of the lower wall segments allowing for thermal expansion, means depending from each lower wall segment so yas to aiford a standard for said bottom support in the furnace except at the aforesaid opposing ends so that said ears and the associated overlapped portions do not carry any of the load of said work-container, and means loosely connecting respective spacing webs of said half castings `at ends thereof.

References Cited in the ile of this patent UNITED STATES PATENTS 677,533 Anderson July 2, 1901 1,610,360 Clements Dec. 14, 1926 2,686,665 Tauber et al Aug. 17, 1954