US2424825A - Method of repairing open hearth furnace banks - Google Patents

Description

29, 1947- I c A'H 2,424,825 umnon 0F ganmme OPEN HEARTH FURNACE BANKS Filed Jay. 16, 1945- INVENTbR. BY (l' zariesifiayagg,

Patented July 2e, .1947

STATI METHOD OF REPAIRING OPEN HEARTH FURNACE BANKS Charles A. Hogan, Chicago Heights, Ill. Application January 16*;1945, Serial No. 573,071 3 Claims. (Cl. 25-1555) This invention relates to a method of repairing or patching the banks of open hearth furnace bottoms. The principal object of the present invention is to make repairs of furnace banks, which repairs are more eflicient than the present day repairs, and to minimize the cost of such repairs.

It is well known to those skilled in the art to which this invention pertains, that the molten metal cuts or washes away furnace banks at the slag line; consequently, repairs must be made after each heat to restore the bank to normal usable condition.

One object of the invention is to provide a thin layer of slag over the refractory material which is used to fill in the cavities, which layer of slag fuses at a considerably lower temperature than the refractory materials, and trickles down through them causing a materials and more effectively resisting the de-' structive action of the molten metal at the slag line on the bank.

With these and other advantages in view this invention consists in the novel method hereinafter fully described and claimed.

The method of. carrying out the invention is illustrated in the accompanying drawing in which the figure is a cross section of a conventional open hearth furnace showing a break in the bank and a repaired cavity.

Referring to said drawing, the reference character l designates an open hearth furnace of conventional construction, having a bed bottom 2, of refractory materials constructed in the customary manner with the bank 3, sloping toward the door openings, one of which is seen at t.

A cavity caused by the action of the molten metal is seen at 5, and at t is shown a cavity which is beingrepaired in accordance with the present method; The cavity may extend around the entirebank and frequently does so.

After the heat has been drawn oif, relatively inexpensive refractory material I, such as dolomite, magnesite or the like is thrown through the door openings into the cavities in the bank,

after which a thin layer of slag 8 is thrown upon the refractory material. Because of the low fusion point of the slag, it melts and trickles down through the refractories and effectively binds them together.

If a cavity is relatively shallow, it may be filled with the refractory material to the original bank surface, and the layer of slag is then spread over the filled in refractory material. If the cavity is relatively deep, it is preferred to only partially fill it with refractory materials and add a layer of slag and then fuse this layer before fusing the I next layer, and subsequently continue the same firmer bond between the because of this condition process until the cavity has been built up to the original bank surface. When the slag fuses, it trickles down into the refractory material.

Since the layer of slag is relatively thin, the heat does not have to penetrate so far as when the slag is mixed with the refractories, consequently the slag is fused quicker and trickles down into the refractories acting as a flux therefor, and making a solid bond between them. Furthermore, inasmuch as th fusion point of slag is much lower than the refractory materials the furnace can be operated at less damaging temperatures than heretofore. The furnace being charged, it is operated at full blast with no attention paid to temperature and since the sl is applied to the outside surface of the repair materials, the fusion point of the refractory materials is diluted, thus increasing th thickness of the surface crust, that is formed over the cavity thereby providing a more efficient repair job. In repairing banks of open hearth furnaces, the refractory materials and the slag may be thrown into the cavities with a shovel or with any suitable apparatus. 1 have found that great emciency is obtained by adding about 8 to 10 pounds of slag, evenly scattered, over each lineal foot.

From the above it is apparent that with my heat from penetrating the necessary depth to fuse all or even very much of the added material; the ordinary material used in the repair of the est efficiency because of quickly. In accordance with my method, cheaper repair materials may be usedmore efficiently and can replace the more expensive materials in many plants, thereby effecting great savings.

The use of dolomite or magnesite for making repairs requires some slag to fuse properly, but with a covering of slag as is practiced with my bank does not give full the lack of slag to fuse it manifestly without the slag facing the bank repair would not be nearly so well fused.

With the proper addition of slag to the surface a more efllcient bank repair is attained, there is a saving in expensive repair materials, with no loss of time, and efi'ectively preventing many break-outs of steel before heats are ready.

I claim as new and desire to secure by Letters Patent: 1 I

, 1. The method of restoring worn away portions of open hearth furnace banks to normal usable condition, which consists in filling in the cavities in the bank with discrete refractory material, and covering said refractory material with a relatively thin layer of slag directly after a heat, and subjecting the slag to the influence of suflicient heat to fuse the same and permit it to trickle into the refractory material, whereby to bond the refractory repair material together.

2. The hereindescribed method of restoring worn away portions of open hearth furnace banks to normal usable condition which consists in filling in the cavities in the bank with discrete refractory material, covering said refractory material with a layer of slag directly after a heat, fusing the slag and permitting it to trickle into the refractory material, whereby to bond the refractory repair material together.

3. The method of restoring worn away portions of open hearth furnace banks, to normal usable condition which consists in placing discrete refractory repair'material in the cavities in the bank, covering said material with a thin layer of slag directly after a heat, and fusing the 35 and Chicago, Ill.

"fusing slag. permitting it to trickle into said material, whereby to bond said material together, addin additional refractory repair material to fill the cavities and, covering the same with slag, and

the ad ed Slag whereby to bond the rerractory repair materials together.

CHAR-1 38 A. HOGAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 2nd edition, copyright 1937 and distributed by the Harbison-Walker Refractories Company, Pittsburgh, Pa. (Copy in Div. 28.)

"The Making, Shaping and Treating of Steel, by Camp and Francis, pages 396, 397, 5th edition,

2nd impression, published by Carnegie-Illinois Steel Corporation, subsidiary in Pittsburgh, Pa.,

(Copy in Div. 28.)

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