US3013510A

US3013510A - Furnace roof and method of making the same

Info

Publication number: US3013510A
Application number: US744733A
Authority: US
Inventors: Howard A Parker; John V Salmi
Original assignee: United States Steel Corp
Current assignee: United States Steel Corp
Priority date: 1958-06-26
Filing date: 1958-06-26
Publication date: 1961-12-19
Anticipated expiration: 1978-12-19
Also published as: GB903670A; ES250159A1

Description

Dec. 19, 1961 H. A. PARKER ET Al.

FURNACE ROOF AND METHOD OF MAKING THE SAME Filed June 26, 1958 IE1 E: 5

//vv/v TORS HOWARD A. PA RKER and JOHN v. 5:24 By Aflorney Unite This invention relates to a furnace roof and a method of making the same and particularly to a roof for an open hearth furnace. Most open hearth furnaces have roofs made of silica brick, but such bricks are not capable of withstanding the temperatures which result when using oxygen in the open hearth. Even prior to the advent of oxygen in open hearth practice, care had to be taken to prevent the silica roof from being overheated. For these reasons, attempts have been made to use basic brick in the open hearth furnace room. However, the greater weight of the basic brick and its lower strength and high expansion at high temperatures makes an arch as used in the open hearth roof incapable of satisfactorily carrying its own weight, particularly when worn thin. Therefore, when using basic roof brick in the arch it had been necessary in the past to use individual hangers for each brick and to support the brick from the steel structure of the furnace. This requires the use of special bricks having lugs or cavities provided in each brick which makes the brick very expensive.

It is therefore an object of our invention to provide a basic furnace roof in which the majority of the bricks are of standard shape.

Another object is to provide a method of making such a roof.

These and other objects will be more apparent after referring to the following specification and attached drawings in which:

FIGURE 1 is a view of the furnace roof taken longitudinally of the span of the arch;

FIGURE 2 is a view taken on the URE 1;

FIGURE 3 is a view taken on the line III-III of FIGURE 1;

FIGURE 4 is a plan view of a standard metal clad basic brick; and

FIGURE 5- is an elevation of the brick of FIGURE 4.

Referring more particularly to the drawings, reference numeral 2 indicates an open hearth furnace having a front wall 4 and a back wall 6. Buck stays S at the front and rear walls extend upwardly above furnace roof I0 and are connected at their tops by means of channels 12 extending longitudinally of the span of the roof. Channels 14 extending transversely of the span of the roof also connect the upper parts of the buck stays 8. The parts so far described, except for the details of the roof, are conventional. A plurality of rods 16 extend transversely of the roof span and are spaced apart longitudinally of the span. The rods 16 are suspended by means of hangers 18 from bars 29 supported on top of the channels 12. The rods 16 pass through holes 22 in steel plates 24 which extend longitudinally of the roof span. Skew back bricks 26 are supported by beams 28 at the front and rear of the furnace. The roof is shown as a ribbed ring arch in which the larger bricks 30, making up the ribs, are arranged on each side of the plates 24. Smaller bricks 32 are arranged between the bricks 3%. The bottom of the plates 24 are shaped to conform to the bottom of the arch of the roof and the top of the plates 24 have notches 34 therein with the notches 34 of each plate 24 being aligned with the notches in the adjacent plates. A beam or rail 36 extending transversely of the span of the roof rests in each set of aligned notches line IIII of FIG- tates Patent 34. Jacks 38 attached to the top tie channels 12 are used to hold the beams 36 down against the plates 24 and the bricks 30 or in case of a plain ring arch against, the bricks in all of the rings. The plates 24 in addition to suspending the brick also serve to maintain the arch contour. It is preferred that the bricks 3i and 32 be metal clad with metal sheets 39 in the usual manner.

In making the roof, conventional arch forms are set in the furnace with the top of the arch extending between skew back bricks 26 at the spring line of the arch. The

bricks

30 and 32 are laid dry on the arch forms in courses or rings extending longitudinally of the span of the roof and the plates 24 are positioned between adjacent rings of the'larger bricks 3i). This may be done by first sliding all of the plates 24 on the rods 22 and then sliding each plate in position befor laying up the brick. We have found that the rise per foot of roof span should preferably be a minimum of two inches and that the bricks should be closely spaced along the length of the span of the arch. Preferably, the expansion allowance across the roof should be no more than .5 along the length of the span of the arch. While four courses of bricks 32 are shown between the ribbed bricks 30, this number may be reduced. In some instances the number may also be increased. After the bricks and plates 24 are installed, the holddown members 36 are inserted in the slots 34 and the jacks 38 adjusted so that the bottom of the members 36 rest on top of the roof. Heat is then applied to the roof with expansion of the roof upwardly being restricted by means of the holddown members 34 and the expansion along the length of the span of the roof being restricted to no more than .5% due to the close spacing of the bricks. This causes the bricks to unite with each other and to fuse to the plates 24. While three spacer plates 24 are shown, the number may vary as deemed desirable.

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

We claim:

1. An arched furnace roof comprising an upper support, fixed skewbacks at each end of the arch arranged so that the distance between the skewbacks remains substantially constant at all times, flat metal plates extending longitudinally of the span of the roof and arranged at spaced intervals transversely of the span of the roof, said plates being carried by said upper support, closely spaced basic bricks between the metal plates with at least part of said bricks in contact with said plates, and hold down members on the top of said roof for essentially preventing upward movement thereof during heating up and subsequent operation of the furnace.

2. The method of making an arched furnace roof from basic bricks which comprises suspending rings of said bricks at spaced intervals transversely of the span of the roof, laying the bricks in each ring in sufliciently close relationship along the longitudinal span of the arch so as to limit the expansion to no more than .5% along the length of the span of the arch during heating up and subsequent operation of the furnace, laying basic bricks between the suspended bricks in sufiicien-tly close relationship along the longitudinal span of the arch so as to limit the expansion to no more than .5 along the length of the span of the arch during heating up and subsequent operation of the furnace, providing hold down members on said roof to essentially prevent upward expansion thereof during heating up of and subsequent operation of the furnace, and preventing any substantial movement of said bricks longitudinally of the arch during heating basic bricks which comprises suspending metal plates extending longitudinally of the span of the roof at spaced intervals transversely of the span of the roof, laying basic bricks between the metal plates with at least some of said bricks contacting the plates and in sufliciently close relationship along the longitudinal span of the arch so as to limit the expansion to no more than .5% along the length of the span of the arch during heating up and subsequent operation of the furnace, providing hold down members on said roof to essentially prevent upward ex pansion thereof during heating up of and subsequent operation of the furnace, and preventing any substantial movement of said bricks longitudinally of the arch during heating up and subsequent operation of the furnace.

4. The method of making an arched furnace roof from metal clad basic bricks which comprises suspending metal plates extending longitudinally of the span of the roof at spaced intervals transversely of the span of the roof, laying metal clad basic bricks between the metal plates with at least some of said bricks contacting the plates and in sufficiently close relationship along the longitudinal span of the arch so as to limit the expansion to no more than .5 along the length of the span of the arch during heating up and subsequent operation of the furnace, the rise per foot of roof span being a minimum of two inches, providing hold down members on said roof to essentially prevent upward expansion thereof during heating up and subsequent operation of the furnace, and heating up the furnace with the bricks prevented from any substantial movement upwardly and outwardly.

5. The method of making an arched furnace roof from basic bricks which comprises suspending metal plates extending longitudinally of the span of the roof at spaced intervals transversely of the span of the roof, laying basic bricks in rings between the metal plates with the bricks in at least some of the rings contacting the plates and the bricks in each ring being in close relationship, providing hold down members on said roof to essentially prevent upward expansion thereof during heating up and subsequent operation of the furnace, and heating up the furnace with the bricks prevented from any substantial movement upwardly and outwardly.

6. An arched furnace roof comprising fixed skewbacks at each eand of the arch arranged so that the distance between the skewbacks remains substantially constant during heating up and subsequent operation of the furnace, rings of basic bricks extending longitudinally of the span of the arch, an upper support for carrying said rings of bricks, rings of non-suspended basic bricks 50 between said suspended bricks, the bricks in each ring prior to heating up being in sufiiciently close relationship along the longitudinal span of the arch so as to limit the expansion to no more than .5 along the length of the span of the arch during heating up and subsequent operation of the furnace, and hold down members on the top of said roof for essentially preventing upward movement of said bricks during heating up and subsequent operation of the furnace.

7. An arched furnace roof comprising an upper support, fixed skewbacks at each end of the arch arranged so that the distance between the skewbacks remains substantially constant at all times, fiat metal plates extending longitudinally of the span of the roof and arranged at spaced intervals transversely of the span of the roof, said plates being carried by said upper support, basic bricks between the metal plates with at least part of said bricks in contact with said plates and prior to heating up being in sufficiently close relationship along the longitudinal span of the arch so as to limit the expansion to no more than 5% along the length of the span of the arch during heating up and subsequent operation of the furnace, and hold down members on the top of said roof for essentially preventing upward movement of said bricks during heating up and subsequent operation of the furnace.

8. An arched furnace roof comprising an upper support, fixed skewbacks at each end of the arch arranged so that the distance between the skewbacks remains substantially constant at all times, flat metal plates extending longitudinally of the span of the roof and arranged at spaced intervals transversely of the span of the roof, means connecting said plates to said upper support, rings of basic bricks between the metal plates with the bricks in at least some of the rings contacting said plates and being fused thereto and to adjacent bricks, and hold down members on the top of said roof for essentially preventing upward movement of said bricks during heating up and subsequent operation of the furnace.

9. An arched furnace roof according to claim 8 in which said bricks are standard shaped metal clad bricks.