US2961805A

US2961805A - Encased refractory brick

Info

Publication number: US2961805A
Application number: US636557A
Authority: US
Inventors: William H Myers; John A Garber
Original assignee: Harbison Walker Refractories Co
Current assignee: Harbison Walker Refractories Co
Priority date: 1957-01-28
Filing date: 1957-01-28
Publication date: 1960-11-29
Anticipated expiration: 1977-11-29

Description

Nov. 29, 1960 w. H. MYERS ET AL 0 ENCASED REFRACTORY BRICK Filed Jan. 28, 1957 INVENTORS -10 /v. Myses m 2: f fimeese w M,Mwfi% 779'6/3 flmeugy;

United Sttes Patent F ENCASED REFRACTORY BRICK William H. Myers, Glen Buruie, and John A. Garber,

Severna, Md., assignors to Harbison-Walker Refractories Company, Pittsburgh, Pa., a corporation of Pennsylvania Filed Jan. 28, 1957, Ser. No. 636,557

1 Claim. (Cl. 50416) This invention, relates to blocks for forming the walls and roofs of industrial furnaces, and more particularly to those in which refractory bricks are enclosed in metal cases.

It is common practice to surround the sides of basic refractory bricks with thin sheet metal cases which oxidize when the furnace is put in operation and thereby bond the bricks together. Such cases generally have open ends, but sometimes they have end flanges bent across the ends of the brick. Such flanges at the bottom of suspended bricks are likely to become so hot as to swing down and form no support for the brick. In such instances or when a case has no ends, a broken section of a brick can slide out of the case and thereby leave a thin spot in the furnace roof at that point. Also, in spite of efforts to firmly fasten the cases to the bricks, it has been found that broken pieces of bricks or an entire brick may slide out of a case during handling and drop on the foot of a workman.

The push for production from industrial furnaces requires that the bricks be heated up and in production as soon as possible. Frequently, the bricks are unable to tolerate this treatment, with the result that the ends are spalled off by the thermal shock. This is not much of a problem after the refractory becomes matured or burned in, because the wall or roof then acts very much like a single unit. However, on the initial heat-up, the bricks behave as small units.

It is among the objects of this invention to provide a furnace brick that is surrounded by a metal case, from which the encased brick cannot escape, and which includes a protective sheet of metal to cushion the brick against the most severe temperature variations.

According to this invention the sides of a refractory brick are engaged by a metal case. Extending across an end of the brick is a metal stirrup, the ends of which extend a short distance along the sides of the case and are secured to it. Preferably, there is such a stirrup at each end of the brick. They prevent the brick from sliding out either end of the case. In some cases, the stirrups are provided with a coating that will retard their oxidation.

The preferred embodiment of the invention is illustrated in the accompanying drawings, in which Fig. 1 is a perspective view of our block; and

Figs. 2 and 3 are reduced vertical sections taken on the lines II-II and IIIIII, respectively, of Fig. 1.

Referring to the drawings, a basic refractory brick 1, which is upright when designed for suspension as part of a furnace roof, is provided near its upper end with a lateral recess 2 for receiving the stem and foot of a hanger (not shown). The brick can be made in one piece as shown, or in two or more pieces separated along vertical planes. In the latter event, the brick units generally are separated by a metal plate as shown in Rochow Patent 2,465,170. Whether the brick is made in one or more parts, at least three sides of it are engaged by a sheet metal case. Preferably, the case extends all the way around the brick and is formed in two parts from metal channels 3 and 4, the side flanges of which overlap Patented Nov. 29, 1960 ICC each other at opposite sides of the brick. Such channels can readily be applied to a preformed brick, or a brick can be molded into one of the channels and then the other channel applied.

It is a feature of this invention that means are provided for preventing the brick or a fractured section of it from sliding endwise out of the case accidentally. Accordingly, a metal stirrup 6 is secured to each end of the case after the case and brick have been assembled. Each stirrup is formed from a U-shaped strip of metal that extends across an end of the brick and then vertically for a short distance along the opposite sides of the block. The vertical end portions of the stirrup are securely attached to the sides of the case whether the case consists of one channel or two of them. When the brick is provided with hanger recess 2 that cuts into its upper surface, the upper stirrup is made narrow enough to fit between the recess and the opposite edge of the brick. To avoid having to use stirrups of two different sizes, the lower stirrup may be made the same width as the upper one. A very convenient way of fastening the stirrups is to insert their ends between the overlapping side flanges of the case and then spot weld the flanges to the stirrups, as at 7 in Fig. 1. Such welding secures the stirrups and simultaneously fastens the two halves of the case together. The stirrups then form end walls for the case to prevent the brick from coming out. If desired, however, the stirrups can be fastened to the case in some other way, such as by an adhesive or by interlocking members. In some cases it may be felt that the upper stirrup is not necessary and can be omitted. When the brick is formed in two units separated by a vertical metal plate, the stirrups make it unnecessary to provide any other means for holding the plate between the two units.

The case is supposed to oxidize when it is heated in the furnace and to thereby bond the bricks together. However, there is no necessity for the stirrups to oxidize, and their oxidation may even be undesirable in some cases by making them too weak to support the bricks. In such cases, it is desirable to first coat the stirrups with a suitable oxidation preventing material so that they will not burn away so rapidly. The utility of the stirrups depends on their metallic properties, rather than upon their conversion to oxides. Protective coatings suitable for this purpose are known. They may be formed from refractory oxides such as magnesia, beryllia, alumina, zirconia and silica.

According to the provisions of the patent statutes, we have explained the principle of our invention and have illustrated and described what we now consider to represent its best embodiment. However, we desire to have it understood that, within the scope of the appended claim, the invention may be practiced otherwise than as specifically illustrated and described.

We claim:

A furnace block comprising a refractory brick having opposite ends connected by two sides, a two-part metal case engaging the sides of the brick and formed from sheet metal channels having overlapping side flanges, a metal stirrup extending across each end of the brick and part way along its sides between said overlapping flanges, and spot welds joining the end portions of the stirrups to the side flanges of both channels.

References Cited in the file of this patent UNITED STATES PATENTS 1,949,079 Loeffier Feb. 17, 1934 2,187,669 Stewart Jan. 16, 1940 2,216,813 Goldschmidt Oct. 8, 1940 2,247,376 Heuer July 1, 1941 2,736,187 Coffman et al. Feb. 28, 1956