US2171776A - Annealing furnace - Google Patents

Description

Sept. 5, 1939.. J. c. WOODSON 2,171,775

ANNEALING FURNACE Original Filed Sept. 28, 1937 2 Sheets-Sheet l INVENTOR James C.Woodso Sept. 5, 1939. J. c. WOODSON ANNEALING FURNACE Originai Filed Sept. 28, 19:57 2 Sheets-Sheet 2 INVENTOR James C.W0odson MMVAJM Patented Sept. 5, 1939 1 UNITED STATES smvmrmo masses James O. Woodson, Cleveland. Ohio,

Lee Wilson Sales Corporation-Cleveland. '05,

a corporation of Ohio Application September 28, 1937, Serhl No. 166,052,

Renewed June 14, 19",;

2 Claims.- (Cl. 266-4) This invention relates to the art of annealing and in particular to a furnace ofthe cover type and a method practiced-with the aid thereof.

In the annealingof sheet or strip material in I! cover type furnaces, it has been thepractice heretofore to place a charge of material on a furnace base, enclose it within a protective, cover, and lower a heating cover thereover. The material being annealed has beenheated by the =radiation of heat from the exterior of the charge .20,.sheets or coils of the smaller sizes, however, as

is sometimes necessary, the efllciency of the annealing operation is impaired because of the considerable time required for the heat delivered by the furnace cover to soak through the 5 stacks of material disposed on the furnace base from the outside 'of such' stacks through the mass thereof to the inner layers or surface. r

I have invented a novel form of furnace of the cover type. which is particularly adapted for simultaneously-annealing a plurality of stacks or charges of .material disposed on a suitable supporting base in spaced relation, and prefer, ably in aligned rows. In accordance with my invention, I provide the furnace cover with heat-v radiating means in the form of radiant tubes along the side walls thereof and mount burners in said tubes, whereby combustion gases passing therethrough heat them to radiant temperature so that they radiate heat to the exteriors of a 40 plurality of stacks or charges in aligned rows from the outer sides thereof.- I also provide heatradiating means similar to those above mentioned between adjacent rows of stacks or charges and suspend them from the furnace cover for radiating heat to stacks in each bf two adjacent rows from the space intermediate thereof. I thus expedite the heating of the charges to the desired annealing temperature by supplying heat to each charge from opposite sides thereof.

The-general arrangement of heating tubes out; lined above is also disclosed and claimed in my copending application Ser. No. 237,423, which is in part a continuation hereof.

The invention may be more fully understood,

bothms to the the. procedural steps .ingolved byreferringto the following descflntlon and the accompanying drawings illustrating ,a .present preferred. 1 embodiment-sand: l mtice'. In the ,drawings: 5

Figural is .a-sectional viewihro sh a furnace according. tothe-.inyentiongalonga central longitudinal. vertical plane;

Figure v2 a sectional view..along the line II--1I:-Of Fi e 1 andindicates at the line I-'-.I 10 the .plenetamwh chribs-sett emen su e- -1 is Aaclearly-shoynin .thefimwings, the furnace comprises. a ll, andi-a cover. i i, removably dispom thereon., TheJiase ll compri s. a 16 structural frame- -i2-,-,;a sheets, -,a refrac-' tory h r h Y.l id=-ihetm.-.i cludi e peripheral .curb ifie'and a bottom plate; ii. 1 which the charge supports- II. are ,in spaced relation, preferably aligned inparallel rows, as 20 illustrated. The bottomate u 'iscovered. with granular sealingmaterlal. it; Protective covers I! are over. chargesllirestiug on the supportslL-and the lower edges. of the covers p ject-into the sealingmaterial Jl..; The charge vas 2.; may, be-..one..or more of strip or a stack of sheets.

The cover ii ,;comprlses refractory side walls 22 and a roof ,,n,-assembled within a frame composed of structuralmembers 24- and sheathing so plates It; The. cover is open 'at, the bottom- -and -is rest on the edge .of the base it; Thelatter is provided witha seal-, ing channel 2!; -containing granular or other sealing material withwhich-a flange 21, depending from the lower edge of the cover II, is adapted to cooperate. Haatgradiatorsin the form of heat exchange tubes 28- are spaced along opposite side walls (preferably the longer side walls) of the furnace cover.

Each of the 'tubeszlrhas a'bfl e'r ii -mounted. in the lower end thereof. 'l'heburners '29 are connected to fuel supply mains II. Arr igniter electrode ii is disposedadiacent'the'tip of burner and is connectedtoan energizing transformer 32. Fuel suppiiedtotheburners 2! from the mains 3. is thus ignited and combustion within the tubes 28, supported by-atmospheric air induced into the lower ends of the; tubes, heats the latterto radiant temperatm'es whereby 5 heat is radiated'to theexteriors of the aligned stacks or charges from the outer sides thereof. After passing through the tubes", the combustion gases are discharged into exhaust manifolds 33, carried on the cover ll.

The remaining side walls 22 are provided with heat exchange tubes 34 extending inwardly therethrough to about the middle of the length of the furnace cover. The tubes 34 are arranged in vertical bands and include, in addition to the horizontal sections 35 thereof, vertical sections 36 extending upwardly through the roof. The tubes 34-are suspended on hangers 31 including rods 33 depending from the furnace roof and stirrups 33 carried thereby. The lower ends of the stirrups 39 engage guide and bearing plates 40, secured to the'bottom plate ii of the base Ill. The outer ends of the horizontal'sections 35 of the tubes 34 are provided with burners 4|, similar to those shown at 29, and fuel supply mains 42 are connected thereto. The tubes 34 are heated like the tubes 28 by the combustion of fuel therein and radiate heat to the exteriors of the rows of stacks or charges on each side thereof from the space therebetween. After traversing the tubes 34, the combustion gases are discharged into a=collector box 43 on the furnace roof. extend laterally from the box 43 to downcomers 45. The latter cooperate with fixed exhaust passages 46 leading to a stack (not shown) or other means for finallly disposing of the gases. Connections 41 between the manifolds 33 and the downcomers provide for the disposition of combustion gases discharged from the tubes 23.

The openings in the roof of the furnace cover through which the vertical portions 36 of the heat exchange tubes 34 extend are closed by sealing channels 48 extending above the openings and depending flanges 49 extending downwardly thereinto from the upper ends of the vertical tube sections. The channels are provided with granular or other sealing material. This type of seal permits expansion and contraction of the vertical tube sections without injury to the furnace roof.

It will be apparent from the foregoing description that the invention provides an annealing furnace and method characterized by numerous advantages over the previous practice in this art. It will be understood that the furnace of my invention is utilized by placing the charges on the supports I! after raising cover i I from the base iii. The protectivecovers I! are then placed and the heating cover ll lowered onto the base.

After the burners have been ignited and the charges brought up to the proper temperature, the furnace cover is removed to another base having thereon charges for annealing, the charges Exhaust ducts 44' on the base i3 remaining thereon until cooled substantially to atmospheric temperature, after which the protective covers I! are removed and the charges unloaded.

Because of the disposition of heating elements between adjacent parallel rows of aligned charges, I am able to heat the latter to the desired temperature in a much shorter time than would be required under the previous practice of radiating heat to the charges from the outer sides thereof only. The novel construction for this purpose shown herein is simple in character and relatively inexpensive so that the increased production rendered possible thereby is not accompanied by any penalty in the form of a material increase in the cost of construction or operation of the equipment.

Although I have illustrated and described herein but a preferred embodiment and practice of the invention, it will be understood that changes in the construction and procedure disclosed may be made without departing from the spirit of the invention or the scope of the appended claims.

I claim:

1. In a furnace, a base and a cover cooperating therewith, hangers depending within said cover, heat-radiating means suspended on said hangers, and guide and bearing plates on said base adapted to receive and support the lower ends of said hangers.

2. In an annealing furnace, a base, a plurality of supports for charges of material arranged on said base in spaced rows, -a cover having side walls, end walls, and a roof, adapted to be disposed on the base and overlie all said supports and charges thereon, heat-exchange tubes extending upwardly along said side walls from points near the lower edgesthereof effective to deliver heat to the outer sides of charges on said supports, substantially horizontal heat-exchange tubes extending inwardly from said end walls, and suspended from said roof between adjacent rows of charge supports for radiating heat to the inner sides of said charges, exhaust tubes connected to said last-mentioned tubes and extendof said side walls, said manifold communicating with said first-mentioned tubes and with said duct.

JAMES C. WOODSON.

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