US3396684A

US3396684A - Basic refractory furnace structure

Info

Publication number: US3396684A
Application number: US585425A
Authority: US
Inventors: William R Mclain
Original assignee: United States Steel Corp
Current assignee: United States Steel Corp
Priority date: 1966-10-10
Filing date: 1966-10-10
Publication date: 1968-08-13
Anticipated expiration: 1985-08-13
Also published as: GB1193694A; ES345608A1; DE1583298A1

Description

ug. 13, 1968 w, R, McLAlN 3,396,684

BASIC REFRACTORY FURNACE STRUCTURE Filed Oct. l0, 1966 Clie/ni l2 cal/y v Bonded Direct Bonded 8 l2 r l 36 3a 3a 24 4 3o 32 9&1 I

nvvE/vrok United States Patent O 3,396,684 f BASIC REFRACTORY FURNACE STRUCTURE William R. McLain, Chicago, Ill., `assignor to United States Steel Company, a corporation of Delaware Filed Oct. 10, 1966, Ser. No. 585,425 8 Claims. (Cl. 11B-99) ABSTRACTH THE DISCLOSURE A basic refractory furnace structure. particularly an r This invention relates to a basic refractory furnace structure and more particularly to an open hearth furnace roof such as shown in Parker et al. Patent No. 3,013,510 dated December 19, 1961. As shown therein vertical steel tie plates are provided between some of the rows or courses of brick. Two types of basic brick have been used in such roofs-chemically bonded and direct bonded. However, roofs made of chemically bonded basic brick fail principally due to peeling of the bricks and roofs made of direct bonded brick fail from peeling and because the tie plates oxidize and melt. Also, there is danger of the direct lbonded brick expanding7 and breaking the furnace support binding. A direct bonded basic brick is one in which there is substantial direct attachment of the magnesia to the chrome ore without an interrupting film of silicate.

It is therefore an object of my invention to -provide a basic refractory furnace structure made of a combination of direct bonded and chemically bonded bricks arranged in such a manner that the life of the furnace structure is greatly increased over that of a similar structure made entirely of either type of brick.

Another object is to provide an open hearth furnace roof which has a decreased cost per ton of steel produced in the furnace.

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 a furnace roof taken longitudinally of the span of the arch;

FIGURE 2 is a view taken on the line II--II of FIGURE l;

FIGURE 3 is a view taken on the line III-HI 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 8 at the front and rear walls extend upwardly above furnace roof 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. 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 20r supported on top of the channels 12. The rods 16 pass through holes 22 in steel tie plates 24 which extend longitudinally of the roof span. Skew back bricks 26 are 3,396,684 Patented Aug. 13, 1968 supported by means 28 at the front and rear of the furnace. The roof 10 is shown as a ribbed ring arch in which the larger bricks, 30, making up the ribs, are arranged in two courses or rows, one on each side of the plates 24. Two courses of smaller bricks 32 are arranged between the bricks 30. 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 34. Jacks 38 attached to the `top tie channels 12. lare 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

30 and 32 be clad with metal sheets 39` in the usual manner.

The parts so far described are conventional and are essentially as shown in the above identified Parker et al. patent. It will be understood that the construction described is illustrative and may be varied. According to my invention the bricks 30 in the courses on each side of the plates 24 are chemically bonded basic brick and the bricks 32 in the courses between the bricks 30 are direct bonded basic brick. The chemically bonded basic bricks have `a modulus of rupture at 2300 F'. of 200 to 300 lbs. per sq. in. and the direct bonded basic brick, at the same temperature, a modulus of rupture of 1200i to 1600 lbs. per sq. in. The analyses of the two types of brick are as follows with all figures being in percentage -by weight:

Chemically bonded Roofs have been provided on open hearth furnaces according to my invention and the indications are that the roof life will be increased by 50%.

While one embodiment of my 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.

I claim:

1. A basic refractory furnace structure comprising a plurality of courses of direct bonded basic brick, a plurality of courses of chemically bonded basic brick, at least some of said courses of direct bonded basic brick abutting courses of chemically bonded basic brick, at least some of said courses of chemically bonded basic brick being arranged in pairs, and a steel tie plate between the courses of the pairs of courses of chemically bonded basic brick.

2. A basic refractory furnace structure according to claim 1 in which said courses of direct bonded basic brick are arranged in pairs between said pairs of courses of chemically bonded basic brick.

3. A basic refractory furnace lstructure according toY claim 2 in which said bricks are encased in steel plates.

4. A basic refractory furnace structure according to claim 1 in which said structure is a furnace roof and the bricks are oblong in cross section with their long dimension generally vertical. Y

5. A basic refractory furnace structure according to claim 4 in which said courses of direct bonded basicbrick are arranged in pairs between said pairs of courses of chemically bonded basic brick.

6. A basic refractory furnace structure according to claim 5 in which said bricks are encased in steel plates.

7. A basic refractory furnace structure accordingto l claim 6 including means for rigidly holding said tie 15 FREDERICK KETTERER, Primary Examiner.

plates in position.

8. A basic refractory furnace structure according to claim 7 in which Vsaid means for rigidly holding said tie plates in position includes beams above said roof, and rigid means connected to and extending between said beams and tie plates.

References Cited UNITED STATES PATENTS