US2245647A - Apparatus for annealing coiled strip - Google Patents

Description

June 17, J D BURBY r APPARATUS FOR ANNEALING COILED STRIP Filed April 8, 1940 INVENTORS James D. Bur-by and Ja m es L; I Vb/f/en and the finished product.

Patented June 17, 1941 UNITED STATES PATENT OFF ICE 2,245,647 r I Y I APPARATUS FOR ANNEALING COILED STRIP I v James D. Burby, Hastings-oh-Hixdso'nQN. Y. and 1 James L. Whitten, Cleveland. Ohio, a'ssign'orsto Anaconda Wire and Cable Company, New Yorl'i, N. Y., acorporation ofDelaware l Application April 8, 1940, Serial Ne. sz'ale f, 6 Claims. 266-) v This invention relates to the art of annealing metal and, in particular, to apparatus for annealing coils of metal-instrand form such as wire,-

ture for annealing. After the material is heated to the proper temperature, the heating cover is removed and the material is allowed to cool from the exterior thereof, the atmosphere being excluded therefrom by a protective cover disposed thereover before 'thefurnace cover is lowered. i l

The present practice of annealingas described above'requires a considerable amount of equipment such as furnace bases and a correspondingly A complete installation tially nostril; p ge ,or it. 'n 1'1 or Fig. 1 with parts omitted.

. Referringnow in detailrto the drawing, the

" furnace shown in Figs. 1.,and..2 comprises an open-bottomed heating cover or bell l0 adapted to. be removablyndisposed.on-a-base II.

' shell l3 of sheathing plates, and a fiat roof I4 of' refractory brick suspended from cross beams l5 to which a lifting block I6 is secured as by welding: An annular bottom plate l3a secured when the cover is positioned thereon.

large floor space, because of the time required for.

the material to cool from the maximum temperature to which it is heated, to a temp ature at which atmospheric oxidation thereof does not tially reduced. By reducing the length of. the

cooling stage of the annealing cycle, it is possible to process the same tonnage with less equipment,, i. e.', furnace bases, and floor space, thanhas been necessary heretofore, thus effecting a substantial reduction in the cost of the processing I In a preferred embodiment of our invention,

a cover type furnace having a base is provided with one or more upstanding tubular guides adapted to center a stack of coils disposed there over and connected to a supply of cooling fluid. The furnace base is also provided with means for circulating the atmosphere within the protective cover to cool the coils from the exterior thereof. M

The apparatus of our invention will be described in detail hereinafter with reference to the accompanying drawing illustrating a preferred embodiment. Inthe drawing,

Fig. 1 is a vertical, central section through a A cover type furnace, the base of which is con-' structed according to our invention; and

Fig. 2 is a partial horizontal section substanto the shell l3 and stiffened by gusset plates l3b carries the wall; l2 and isadapted to engage a portion of the base H to bereferred to later,

; Curvilinear heat-exchange tubes ll ference of the cover with their intermediate portions exposed inwardly thereof and their end portions passing out through suitable openings in theside wall l2. The spaces between the tubes and these opehing's are closed by seals l8 and I3. A burne'r'2ll extends into the lower end of 'each'tube ll'anfd is connected to a circumferential fuel supply main or header 2| by a flexible pipe'22. The supply-of fuel from the header 2| to each burner is controlled by a valve 23.

' Spark-gap igniters 24 are secured to the tubes I I adjacent their upper ends and connected to energizing transformers 25 mounted on the exterlor'of ,the sidewall of the cover.

The base I] comprises a structural frame 26 including abottom plate 21 and a central cylinder 28. A charge-supporting hearth 29 is built up of refractory brick on the bottom plate 21. "A

.peripheral' sealing channel 30 extends around the hearth 29'and has a partition 3i disposed concentrically therein providing a pair of 'ad- -jacent annular containerslfor sealing liquid;

The hearth 2a isprovided with a cover '32 uof'heat-resistant alloy such as chromium steel.

The outer edge of this covering extends downwardly between the inner wall of the channel 30 and the partition 31. and below the surface of the sealing liquid contained therein A charge-support 33, preferably in the form of a casting of heat-resistant alloy is disposed on the hearth 29, on top of the cover 32 thereover. The support 33 is in the form of a hollow annulus of box section having openings 34 in the vertical walls thereof and openings 35 in the horizontal walls. A grille 36 of heat-resistant alloy is removably disposed over an opening in are. .mounted in spaced relation about the. circumthe center of the upper horizontal wall of the casting.

Upstanding tubular guides 31 extend upwardly above the support 33 and are spaced circumferentially thereof. Each guide 31 comprises a length of pipe closed and tapered at its upper end and detachably secured by a'coupling 31a to a tube 38 preferably of heat-resistant alloy, embedded in the hearth 29 and threaded into a coupling 39 welded to the bottom plate 21: The guide 31 itself may be of ordinary steel pipe since it can readily be replaced on deterioration. A second length of pipe 40 is threaded into the coupling 39 and has a closure 4| welded to the end thereof. The closure 4| has a hole therethrough which is tapped to receive a pipe 43 extending upwardly through the guide 31. An extension 42 of the pipe 40, is welded to the closure 4| at one end, its other end being closed. Radial connections 44 and 45 permit cooling fluid such as water to be circulated upwardly through the pipe 43 and downwardly through the guide 31.

The coils of material to be annealed are stacked and lowered over the centering guides 31. In the drawing, we have illustrated as the material being processed, wire coiled on metal reels 46. As shown in the drawing, each. reel 46 comprises a central tube 41, an annular channel 48 and discs 49 extending between the tube and channel and welded thereto. The tube 41 has an inside diameter sufficiently greater than the outside diameter of the guide 31 to facilitate positioning of the reels on the support 33 and their removal therefrom.

When stacked reels have been lowered over the guides 31 and onto the support 33, as shown in Fig. 1, the cover I being raised from the base during the loading operation, a protective cover 50 is lowered over the charge. The cover 50 is an open-bottomed enclosure of metal plate having a downwardly flaring portion adapted to lie between the hearth 29 and the bottom of the cover when the latter is lowered into position so that its bottom plate |3a rests on the outer wall of the channel 30 which is stiffened by gussets to adapt it for supporting the cover. tective cover 50'has bottom flanges 52 and 53 adapted to extend downwardly into the sealing channel 36 on opposite sides of the partition 3| and rest on the bottom thereof. After the protective cover 5|] has been placed over the charge, the heating cover i0 is lowered to the position in which is it shown in Fig. 1.

The annealing operation for which our apparatus is adapted is usually a continuous process, the burners 20 in the tubes H of the cover Ill being fired steadily so that heating of the charge starts immediately on lowering of the cover. As previously indicated, furthermore, the cover l0 cooperates successively with a number of difierent bases whereby while the cover is heating a charge on one base, the charge on another base is cooling and a charge is being removed from or disposed on still other bases.

The tubes l1, being heated to radiant temperature by the combustion gases traversing them, radiate heat to the protective cover 50 which in turn radiates heatto the coiled material on the reels 46. To expedite heating of the material to the desired temperature, we provide an impeller 54 mounted on a shaft 55 extending vertically through the center of' the hearth 29. The shaft 55 extends upwardly from a motor reducer 56 disposed in and secured to the cylinder 28. It willbe apparent that when the impeller 54 is The prodriven, it tends to circulate the atmosphere within the protective cover 50 outwardly through the openings 34, upwardly along the side wall of the cover 50 and downwardly along the axis of the base and cover and through the grille 36. desired atmosphere may be maintained within the cover 50 by means of connections 51 and 58. Usually a deoxidizing atmosphere is desirable.

When the charge has been heated to the desired temperature as determined by a thermocouple 59, the cover in is lifted and disposed on another base whereon the next succeeding charge has been placed. Cooling of the charge on the base N then occurs by radiation from the coils on the reels to the cover 5|! and atmospheric cooling of the latter. If the impeller 54 is operated during the cooling stage, cooling of the coils is efiected by convection, the atmosphere within the cover 50 circulating as already explained around the stacked coils and transferring heat to the cover 50 by convection.

Cooling water is supplied through the connection 44 and the pipe 43, by operating suitable control valves. The cooling water flows out through the pipe 43 into the interior of the guide 31. The water'will be partially or wholly vaporized and the vapor and water, if any, are taken off through the connection 45. The circulation of cooling water through the guides 31 serves to cool the interior of the stacked coils eflectively, the heat being transferred from the coils on the reels to the guides by radiation. The heat absorbed from the interior of the coils, of course, is disposed of by the downward flow and discharge of the water delivered to the interior of the guides.

By cooling the interior of the coils, the cooling stage of the annealing cycle is materially shortened and the entire processing operation expedited. As a matter of fact, the cooling stage is shortened sufliciently to make it possible to carry on a continuous processing operation with only three bases for each cover, instead of four as required heretofore. This reduces the cost of the equipment necessary to process a given monthly tonnage. Since only three bases are required, the amount of necessaryfloor space is also reduced. All these results contribute to a reduction in the cost of the finished product.

A further advantage resides in the fact that by cooling the coils interiorly as well as exteriorly, a greater uniformity of the characteristics of the product is obtained since all portions of the coils cool at more nearly the same rate than when treated according to the prior practice.

By making the coupling 31a. of steel, the difference between the coeflicient of thermal expansion thereof and that of the alloy tube 38 causes the joint therebetween to tighten .on heating, decreasing the possibility of leakage at the point where the guides 31 are removably attached to the remainder of the fluid circulating system.

Although we have illustrated but a preferred embodiment of the invention, it will be understood that changes in the apparatus disclosed herein may be madewithout departing from the spirit of the invention or the scope of the appended claims.

We claim:

1. A furnace base adapted to receive material in coils for enclosure by a heating cover, said base including a coil support, an upstanding tubular guide tapering to a point at its upper end, rigidly attached to said'base and thereby adapted. to center coils disposed on the support,

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and connections for supplying cooling fluid to said guide.

2. A furnace base adapted to receive material in coils. for enclosure by a heating cover, said base including a coil support, a tube extending through said base, a hollow guide tapering at its upper end, communicating with said tube and rigidly mounted thereon and thereby adapted to center coils disposed on the support, and connections for supplying cooling fluid to said tube.

. 3. A furnace base as defined by claim 2 characterized by said guide being detachably connected to said tube.-

4. A furnace base adapted to receive material A in coils for enclosure by a heating cover, said base including a coil support, an upstanding tubular guide rigidly mounted on said base and thereby adapted to center coils disposed on the support, a pipe v extending through said guide substantially to the upper end thereof, and cooling fluid connections to said guide and pipe.

5. A furnace base adapted to receive material said closure.

6. A furnace base adapted to receivematerial in coils for enclosure by a heating cover, said base including a .coil support, means below said support for circulating the-atmosphere surround ing said coils, hollow coil guides extending from said base through and above said support and spaced circumferentially about said means, and

connections for circulating cooling liquid through the coil guides. l

JAMES D. BURBY. JAMES .L. IWHITI'EN.

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