US2075115A - Annealing box - Google Patents

Description

March 30, 1937. P. E. HUNTER ET AL ANNEALING BOX Filed Feb. 17, 1936 2 Sheets-Sheet 1 10 Weld czawz 3 e Q KE Q .gpcism czar-7) Patented Mar. 30, 1937 UNITED STATES ANNEALIN G BOX Percy E. Hunter and Kenneth J. Deahl, Pittsburgh, Pa.; said Deahl assignor to said Hunter Application February 17, 1936, Serial No.. 64,329

9 Claims.

This application is a continuation in part of our application Serial No. 40,882, filed September 1'7, 1935, and relates to annealing boxes employed in the heat treatment of metal, and is hereinafter described as of the sheet metal type.

Annealing boxes as heretofore constructed represent a considerable initial investment and are short lived and have to be replaced very frequently, since they will retain their shapes and eifectiveness for only a very limited number of heats. The roofs or tops thereof in time become permanently sagged to such an extent that they will no longer accommodate a desired charge of material to be treated. Furthermore,

the sides will become bulged, and otherwise distorted, so that the boxes cannot be placed in the furnaces. Also, distortions through unequal temperature changes frequently are so pronounced that cracks and fissures develop in the walls of the boxes.

One object of our invention is to provide an annealing box structure of such form that the distortions through temperature changes are confined to definite lines of bend, about which lines the metal will flex both when expanding and contracting, so that the walls of the box will always return to approximately their original positions, upon cooling. I

Another object of our invention is to so design the box that the bending or distortion through temperature changes can take place in various portions of the box without creating excessive strains at other portions or at the juncture of cooler and hotter portions.

Still another object of our invention is to provide a reinforcing element of hollow form so constructed and arranged that the box is adequately reinforced against distortion in the vicinity where a portion of the box that becomes very highly heated in use adjoins another lower portion thereof that normally does not become heated to a very high temperature.

Some of the forms which our invention may take are shown in the accompanying drawings wherein Figure 1 is a longitudinal sectional view,

through an annealing box; Fig. 2 is an end view thereof, partially in section Fig. 3 is a fragmentary plan view; Fig. 4 is an enlarged view taken on the line IV-IV of Fig. 3; Fig. 5 is a fragmentary longitudinal sectional view of a modified form of box; Fig. 6 is a fragmentary side view of another form of box, partially in section; Fig. 7 is an enlarged view taken on the line V'lI-VII of Fig. 6 Fig. 8 is a view taken on the line VIII-VIII of Fig. 7; Fig. 9 is a view similar to Fig. 8, but showing another modification, and Fig. 10 is a similar view showing still another form.

' Referring; first to Figs. 1 to 5, the box is shown as constructed of 'sheet metal, but it will be understood that various features of the invention are applicable also to boxes formed of cast met-a1. The box is provided with side walls l0, end walls H, and a top wall l2, formed of plates which are welded together at their abutting edges to produce a unitary box structure.

The walls of .the box are so shaped as to have inwardly and outwardly-exposed channels, l3 and IA formed therein that are substantially coextensive with the walls of the box, the chan- 15 nels in the side walls matching the channels in the top wall and being in effect continuous therewith. These channels, ofcourse, serve to stiffen the structure and enable it to be made of lighter gauge material than would otherwise be possible.

The temperature changes to which the box is subjected are, of course, very great, and the tendency toward distortion or deformation is very great, owing to the fact that parts of the box become heated or cooled much more quickly than other parts thereof. If the distortional movements are confined to certain zones or lines, the parts of the box will, after expansion under heat, be restored to approximately their original position and shape upon cooling.

In the present case, the bending movements will occur at and adjacent to the lines of corners I6 and ll of the various channels, and this result is secured by stiffening the webs or bottom walls of the channels by striking up grooves or 35 depressions l8 therein along lines extending transversely of the channels.

It will be seen that when the box expands through the application of heat, it will bend much more readily along the lines l6 and I1 than along lines extending. longitudinally of the bottom walls of the channels, since the grooves or struck-up ribs l8 will resist bending on such median lines of the channels. When the box cools, bending will occur in the reverse direc- 45 tions along the lines l6 and I1, and the boxessume approximately its original shape.

A sufficient number of reinforced channels are provided to insure that the total of expansive movement isdistributed at sufficiently numerous points to prevent excessive strain of the metal in any one area. It will be understood that the webs of the channels can be reinforced by means other than the depressions l8, as by means of small 55 metal members I On welded to the webs of the channels, at suitable points as in Fig. 5.

Another difllculty encountered in the use of annealing boxes is that of the roof sag in in such manner that it not only extends too low into the box, but causes bulging and distortion of the sides of the box. To overcome this dimculty, I supplement the roof channels by supporting elements which can rest upon the pack of sheets or other material inthe box. At various suitable points in the top wall of the box, I provide sleeves 20 through the bottom walls of which extend studs or pins 2| which may suitably be of refractory material such as clay or metal of low thermal conductivity. The stud 2| is provided with a head which will prevent its falling out of the sleeve 20, but is loosely supported in the sleeve. An air seal 22 of sand or other suitable material is placed above the stud 2|.

An adjustable locking element 23 is provided for limiting the upward movement of the stud 2|, so that adjustments can be made whereby the stud 2| will be limited in its upward movement, and thereby permit adaptation of the supporting device to sheet packs 25 of various heights within the box.

The member 23 is held in various adjustable positions by means of a pin 24 that extends through walls of the sleeve 20, to engage grooves in the member 23. It will be understood that with the parts in the position shown in Fig. 4, the top wall l2 will be held against sa ing by the stud 2|.

Annealing boxes commonly have their lower edges resting in and sealed by a body of sand 28, and the furnace heat usually impinges against the box at points some distance above the sand. The result is that there is a wide difference in temperature as between the upper portions of the box and the lower edges thereof.

At approximately the line of greatest difference in temperature, we provide a hollow rib-like reinforclng element 28 that extends peripherally of the box and functions as a stifiening rib. In prior structures these peripherally-extending ribs have usually been formed by simply forming a groove or channel in the side and end walls of the box, the groove being exposed inwardly. Frequently, the difference in temperature between the upper and lower edges of the grooves or channels is so great that excessive distortion of the box occurs in the vicinity of the channel. In order to more nearly equalim and distribute the temperatures at the zone, we apply the reinforcing channel 28 to the outside of the walls of the box. The edges of the channel-like element 23 are welded to the box walls and the flanges thereof are cut away so as to fit the outwardly-protruding channels l3.

In order to compensate for weakening of the channel 23 which is caused by cutting it away where it extends across the channels l3, at those points, we weld strengthening plates 30 to the inner walls of the box.

Referring now to Figs. 6. 7, and 8, we show a box which corresponds somewhat to the box shown in Figs. 1, 2, and 3, but wherein the peripheral channel 33, which corresponds somewhat to the, peripheral channel or groove member 23 has its edges welded to the side and end sheets of box, and has its flanges cut away so that they will snugly fit the outer surfaces of the ribs 32 which correspond to the ribs or corrugations i 3 of Fig. 1. In order that there will be no confinementofairwithintheperipha'airibaind consequent tendency to overheating of the rib, holes 34 are provided in the rib, at suitably spaced points.

At points generally opposite to where the channels 33 are cut away to fit the hollow ribs 32, we weld small plates or bars 33 tothe inner wall of the box which members serve as tie elements or stiffening members to resist deformation of the box at those points. y

In Figure 9, we show a peripheral channel 31, which corresponds to the channel 33, but which is set between and welded to upper plates 33 and lower plates 33. These plates or sheets may be of the same form as the side walls of the box shown in Figs. 1, 2, 8. The channel 31 is therefore exposed inwardly to the box and no holes such as the holes 3. are required in order to avoid the confinement of air in the channel.

The depths of the vertical corrugations in the sheets 33 and 33 are so great as to overlie the major portion of the channel .31, whereby these members reinforce one another and a tie plate at the inner wall will not usually be required.

Referring now to Fig. 10,]: show a structure similar to that of Fig. 9. but wherein the depth of the channel I and thedepth of the corrugated plates 42 and 43 ,diilerto such extent that the corrugations overlie only about one-half of the width of the channel 4i, wherefore, short stiffening plates or bars M are welded to the inner wall of the box at suitable intervals strengthen the channel.

We claim as our invention-.-

1. An annealing box of: sheet-metal. having channels formed in its-walls. the web portions of the channels being provided with elongated depressions extending transversely thereof.

2. An annealing box otxsheet-metal, having channels formed in itswaifi, adjacent channels being exposed inwardly and outwardly, respectlvely, and merging with one another, and means for stiffening the channels agahist bending movements along longitudinally-extending areas between the zones of said merging.

3. An annealing box having a peripherallyextendlng reinforcing channel disposed exterior-1y of the box, along horlseutal lines located adjacent to, but a substantial distance above the lower edge of the box, the flanges ef the channel being welded to the sides of the box.

4. An annealing box having vertically-extending corrugations in its side walls and provided with a horizontally-extending reinforcing channel on its exterior surfaces, the channel having its flanges welded to said and portions of itsiiangesbeingcutamtoiittheeorrugae tions.

5. An annealing box havinga hollow rib disposed peripherally thereof in a plane adjacent to, but located at a distance above the lower edge of the box, the rib having its edges abutting the outer wall surfacesof the box, and being provided with openinal to the 6. Anannealing having upper and lower sidewall portions provided with vertically extending corrugations, and hollow ribs interposed between the adiacent edgges'of said portions and secured to the ends of said corrug tions.

7. An annealing box having upper andlower side wall portions providd'wlth vertically'extending corrugations, ribs between the adjacent eugevoi said portions and secured to the ends ofsaid corrugations. the inner edges of the ribs flush 8. An annealing box 01' sheet metal, having channels in certain 01' the wall areas. the bottom walls of the channels having transversely-extending stifl'ening devices thereon at various 5 points throughout the length of the channels.

9. An annealing box having upper and lower side wall portions provided with vertically extending corrugations, hollow ribs interposed between the adjacent edges of said portions and secured to the ends or said corrugations, and tie members secured to and bridging the inner edges of the ribs.

PERCY E. HUNTER. KENNETH J. DEAHL.

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