US2660420A - Annealing base construction - Google Patents

Description

N0V- 24, 1953 J. E. RcEuNsoNy ANNEALING vBASE CONSTRUCTION Filed Jan. 9, 1,952

w N 0 mm w -n. m m @YA B. Q u. W NN W .M mm wfm W N W Q W W H Iv u N W E du w m i Q \w\ HLW Rmn. Q Q E s Hwr N Patented Nov. Z4, 1953 ANNEALING BASE CONSTRUCTION James E. Robinson, Pittsburgh, Pa., assigner to United States Steel Corporation, a corporation of New Jersey Application January 9, 1952, Serial No. 265,587

, The present invention relates generally to the construction of annealing furnace bases and more particularly to the structure of the sidewalls of such bases.

In a conventional annealing furnace base the inner surfaces of the lbrickwork forming the base sidewalls define a rectangular opening within which are located the coil supporting stands. The brickwork of the sidewalls is not reinforced on its inner surface with the exception of the bottom two or three courses. The outer surface is backed-up by a steel plate which extends completely around the periphery of the furnace base. As a result of this type of construction when the furnace cover is placed on the base and heat applied, the top courses of the brick sidewall are exposed to extremely hot radiant heat which causes considerable expansion of the brickwork. Since the wall is reinforced on only one side by the steel plate, expansion in that direction is restrained and therefore there is a strong tendency for expansion to take place toward the center of the base. When the brickwork is new the inherent strength of the material is adequate to resist this expansion. However, after repeated heating and cooling the bricks deteriorate, becoming gradually less able to resist the expansion, until complete failure and crumbling of the sidewalls occur. When this happens the furnace must be shut down and the base rebuilt with attendant losses in annealing production.

It is accordingly an object of my invention to provide a sidewall structure for annealing furnace bases wherein the brickwork is both adequately reinforced and at the same time suiciently elastic to resist the deteriorating effects of high radiant heat.

This and other objects will become more apparent after referring to the following specication and attached drawings, in which:

Figure 1 is a top plan view;

Figure 2 is a cross sectional View taken on the line II-II of Figure 1; and

Figure 3 is a sectional view taken on the line III-III of Figure 1.

Referring more particularly to the drawings, reference numeral 2 indicates generally an annealing furnace base having endwalls 4 and sidewalls 6. The inner surfaces of the walls define4 a rectangular opening 8 wherein are contained coil supports I0. The sidewalls 6 of the furnace are divided into pairs of brickwork arches I2. The division of each sidewall into four equal parts is essential to minimize the concentration of resultant expansion stresses and maintain these 3 Claims. (Cl. 263-46) values within the crushing strength of the material used to make up the sidewall. Courses of conventional fire brick I4 are arranged in arch form superimposed upon courses of insulating brick I6 also arranged in arch form, the entire wall being supported on a steel platel which forms the bottom of the base. Slotted fire brick skewbacks 22 are disposed around each of the reinforcing members 20 and abut the end bricks of each of the adjacent arches as shown in Figure 1. A steel side or back-up plate 24 is positioned parallel with and spaced slightly from the outer surfaces 26 of the sidewalls 6. Welded steel support or reinforcing members 20 are positioned between adjacent arches and securely welded or otherwise attached to the base plate I8 and to the side plate 24. The intervening space between the brick larches I2 and the steel plate 24 is substantially filled with insulating concrete 28. As best shown in Figure 1, a thin layer of ake asbestos 30 is provided between the arches I2 and the insulating concrete 28 and also between the arches I2 and the plate 24 to provide an eXpansion cushion. The inner end of the slot between each pair of skewbacks as indicated at 23 is also filled with flake asbestos.

lThe arch construction of the sidewalls 6 provides resistance against inward expansion upon heating while at the same time the multiplicity of arches in each sidewall together with the skewbacks and reinforcing members provides adequate strength for the sidewall structure. The insulating concrete between the rearward sides of the arches and the steel plate 24 together with the two thin layers of flake asbestos provides resistance against expansion of the brick work in that direction as well as an expansion cushion which permits the limited amount of expansion necessary.

While I have shown the sidewalls made up of a specific number of courses of insulating brick and fire brick it will be noted that the number of courses may be varied as desired.

While one embodiment of my invention has been shown and described it will be apparent thatl other adaptations and modifications may be made without departing from the scope of the following claims.

I claim:

1. sidewall structure for an annealing furnace base comprising a metal supporting plate, a plurality of spaced brickwork arches disposed in longitudinal alignment on said supporting plate, vertical metal reinforcing members disposed between said arches, a metal back-up plate disposed parallel with and spaced slightly from the rearward side of said line of arches, and insulating means contained in the space between said arches and said back-up plate.

2. Sidewall structure for an annealing furnace base comprising a metal supporting plate, a plurality of spaced brickwork arches disposed in longitudinal alignment on said supporting plate, each of said arches including a plurality of courses of insulating brick disposed on said metal plate and a plurality of courses of iire brick superimposed on said insulating brick, vertical metal reinforcing members disposed between adjacent arches, a iire brick skewback fitted between each reinforcing member and each adjacent arch, a metal back-up plate disposed parallel with and spaced slightly from the rearward side of said line of arches, and insulating means contained in the space between said arches and said back-up plate.

3. sidewally structure for an annealing. furnace base comprising a steel supporting plate, a. plu rality of spaced brickwork arches disposed in longitudinal alignment on said supporting plate, a steel back-up plate disposed parallel with. and spaced slightly from thev outer side of said line of arches, each of said arches including a plurality of courses of insulating brick disposed on said supporting plate and a plurality of courses of fire brick superimposed on said insulating brick, vertical metal reinforcing members disposed between adjacent arches, said reinforcing members being attached to said supporting plate and to said back-up plate, a re brick skewback iitted between each. reinforcing member and each adjacent arch, insulating concrete contained in the space between said arches and said back-upg plate, and a relatively thin layer of flake asbestos between said arches and said insulating concrete and between said arches and said back-up plate to provide an expansion cushion.

JAMES E. ROBINSON.

References. Cited in the le of this patent UNITED STATES PATENTS Wehr Oct. 25, 1949

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