US3092051A - Basic open hearth roof construction - Google Patents

Description

June 4,1963 G. SHAPONA ETAL 3,092,051

BASIC OPEN HEARTH ROOF CONSTRUCTION Filed May 27. 1960 3 Sheets-Sheet 1 iLL b' INVENHRS Gear e Sluyvomw y flowaz' delBmzmfz ATTORNEYS June 4, 1963 G. SHAPONA ETAL 3,092,051

BY FWMWJ M ATTORNEYS June 1963 e. SHAPONA ETAL 3,0

BASIC OPEN HEARTH ROOF CONSTRUCTION Filed May 27. 1960 3 Sheets-Sheet 3 INVEN TORS George Shapozza/a,

By llowa/zvleflBrown '3 ATTORNEYS United States Patent f 3,092,051 BASIC OPEN IEARTH ROOF CONSTRUCTION George Shapona, Greenville, and Howard J. Brown, Clark, Pa, assignors to Sharon Steel Corporation, Sharon, Pin, a corporation of Pennsylvania Filed May 27, 1960, Ser. No. 32,204 4 Claims. (Cl. 110-99) This invention relates to a roof construction for a metallurgical furnace. More particularly it pertains to a basic brick proof construction for an open hearth furnace.

The use in recent years of basic rather than acid (silica) bricks for the flame exposed surface of roofs of open hearth furnaces has been increasingly desired and many constructions have been proposed and used. Basic bricks ordinarily are composed of rnagnesite and chrome in Varying proportions. Often they are metal plated or encased and also reinforced with internal metal plates to reduce spelling when subjected to elevated temperatures (2800 F.3250 R), which was formerly a weakness :of basic bricks. Moreover, wear or erosion of the flame exposed surfaces of open hearth furnace roofs is not uniform. In the ideal construction of an open hearth furnace all parts should wear out at the same rate so that only one shutdown is required for a complete rebuilding of the furnace.

One advantage of a basic roof over an acid roof is that the former can withstand temperatures of above 3250" F. as compared with a maximum of about 3000* F. for an acid (silica) roof without apparent damage. A basic roof can be heated faster so that the furnace can be put into production sooner. This in part compensates tor the higher cost of basic brick. Also, the basic roof lasts on the average about twice as long as a comparable silica roof because it is more resistant to the corrosive effects of heat and chemical action.

Most of the basic roofs recently proposed are of sprung arch or sprung-suspended construction with varying amounts of suspension ranging from almost none to full suspension. In many prior roofs, whether suspended or unsuspended, a complicated rigid steel superstructure is required, not only to hold up the roof, but also to yieldingly hold the roof against the effects of expansion. The intended purpose :of such prior roof constructions has been to remove stress from the hot face or flame exposed surface of the bricks to prevent spalling.

The conventional procedure for installing most prior basic roofs of the sprung arch type, whether suspended or unsuspended, is to provide wooden forms on which the bricks are placed. Most such roofs use l-beams running from end to end longitudinally of the furnace axis and at different horizontal levels, depending upon the arch, to form the roof contour. These beams in turn are mounted, sometimes yieldingly, on a rigid furnace superstructure. Tie plates are also provided between courses of bricks and perpendicular to the l beams at spaced intervals. Frequently the bricks are suspended from the tie plates individually on wire hangers. Moreover, the individual bricks have been notched in some manner, and thereby weakened, to provide for hanging or suspension.

It has been found, however, that a sprung larch roof having means merely for holding up the brick without additional holddown devices has been unsatisfactory because the basic brick roof expands upwardly when heated and subsequently collapses. The reason for the ultimate collapse of the roof is that when the roof expands upwardly upon being heated, the weight of the arch, which was originally borne by the bricks, per se, in complete surfaceto-surface contact with each other, is borne only by the lower edges of the bricks. That is, in the expanded position the upper brick surface portions move out of complete surface-to-surface contact with each other, leav- 3,992,51 Patented June 4, 1963 2 ing only the lower edge portions in pinched positions to bear the load of the arch. Ultimately the lower edges yield to the heat and weight and may be crushed, so that the gradual spalling results in collapse of the arch.

The roof construction of the present invention avoids prior difficulties and utilizes Wedge-shaped, unnotched, metal-encased basic brick. The brick casing includes preferably a pair of integral hanger members or hooks by which each brick is hung in place on an overhanging arch member. Bach arch member preferably comprises an al enate-shaped H beam, l-beam, or inverted T beam having a lower flange extending across the top of the furnace from the front to the rear sides. The hanger members or hooks for each brick are engaged on and suspended by the lower flange of one beam. The bricks are placed in side-to-side and course-to-conrse abutment, respectively, with bricks in the same course and in adjacent courses, to provide the complete basic roof for the furnace. Also, the upper end of each unnotched brick is engaged and held by an arch member against upward movement. That is, each brick is individually and directly held down by an arch member as well as being suspended by such arch member.

'In addition, the ends of each arch member beam are secured in place at opposite sides of the furnace so that the beams not only hold up each brick but also hold down each brick to prevent the arch of bricks from expanding or swelling upwardly in the prior manner as the roof absorbs heat from the furnace in operation.

The roof construction of the present invention also preferably utilizes metal fusion plate-s formed of metal of substantially heavier gauge than the casing metal for the individual brick. These tfiusion plates also are provided with hanger members, books or means which cooperatively engage the lower flange means of two adjacent arch members or beams. Bach fusion plate preferably has a length from its hanger means to its lower end, equal to the length of any brick from the bnicks hanger means to its lower end. Each fusion plate also has a width equal to the width of two bricks and to the spacing between adjacent arch beams or members.

The fusion plates are hung from the opposed flange means of two adjacent arch beams and span the centerto-center distance between the arch beams, and also span the arch course of brick hung from a lower flange at one side of one beam and the abutting arch course of brick hung from the opposed lower flange at the other side of an adjacent beam. Furthermore, the fusion plates are inserted at intervals along the brick arch courses between say every three or more bricks to accomplish several important functions.

First of all, the fusion plates, in being formed of heavy gauge metal and in being hung from the metal arch beams, provide a path for the dissipation of heat from the roof refractory.

Second, when the improved roof has been erected and the furnace heated up, some fusion may take place between the fusion plates, the contacting metal-encased bricks, and the brick refractory to more completely integrate the roof.

Furthermore, (as heating within the furnace continues by continued exposure of the internal surface of the roof to the furnace flame, the flame exposed ends of the brick refractory material may burn 0E somewhat. At the same time the inner ends of the individual brick metal casings as well as the fusion plates may burn back further between adjacent bricks than the refractory burn-off. This burn-01f or burn-back at the flame exposed surface of the roof is accompanied by a rearrangement of the compounds and complex reactions under the high operating temperatures involved.

Reactions between iron oxide originating from the metal of the brick metal casings and the metal fusion plates, and the brick refractory material may cause a swelling of the inner ends of the brick at and adjacent the flame exposed surfaces. In prior constructions, such swelling sometimes resulted in a build-up of crushing pressures between adjacent brick which contributed to an increased spalling eifect.

However, the spaces left in the zones where there has been fusion plate burn-back, at the intervals along each course of every three or more brick where the fusion plates are located, provide spaces for swelling of the flame exposed brick refractory material ends without a build-up of damaging, crushing forces incident to swelling.

One of the outstanding aspects and advantages of the improved construction is that unlike prior constructions it is simple to install and requires a minimum of parts. Inasmuch as each brick is provided with at least one integral hanger member for attaching directly to a fixed supporting arch beam, rather than being suspended by interconnecting wires, tie plates, etc. of prior constructions, no separate arch forms are required to be installed upon which the improved arched roof is erected. Such forms required by prior constructions must be subsequently removed after the roof is completed. The material and labor installation and removal costs of such temporary arch forms, necessary for erecting arched roofs of prior construction, are thus completely eliminated. Moreover, the encased, unnotched basic bricks used in accordance with the invention, having integral hanger members or hooks, may be installed readily by unskilled labor. Thus, skilled brick masons are not required to lay up the arched roof, so that an additional cost item is eliminated.

The elimination of forms required by prior constructions for roof erection has a further advantage in accord ance with the invention. Thus, the improved roof may be readily, quickly and easily patched at low cost where necessary, Without the erection and removal of forms by simply removing the bricks requiring replacement and hanging new bricks in their place.

With regard to the connecting parts required, each brick used in accordance with the present invention has its own integral hanger member or means which is attached directly to the arch-forming beam rather than indiie'ctly through interconnecting wires, tie plates, etc. as in prior constructions. As a result, the number of different parts necessary for the improved construction is maintained at a minimum.

A further aspect of the invention from the standpoint of a reduced number of parts or elements utilized in the improved construction is that only two different encased,

unnotched basic bricks are used, namely, a regular brick and a key brick, each of which has the same wedgeshaped configuration. The only difference between the regular and key brick is the location of the integral hanger means therefor.

Moreover, the arch-forming beams include lower flange means on which the bricks are hung to carry or hold the weight of the bricks. When the bricks are thus hung, the upper ends of the bricks abut the undersurface of the flange means so that the bricks also are held down in place in complete side-to-side abutment with each other. By bolting down the opposite ends of each beam the entire assembly is prevented from expanding or heaving upwardly from the furnace heat in operation.

The arch beams are equally spaced at intervals with a spacing substantially equal to the width of two bricks. Thus, the bricks in one course hung from a lower flange at one side of one beam are in abutment with similar bricks in an adjacent course hung from a lower flange at the other side of an adjacent beam. Similarly, the bricks hung from the lower flange at the other side of said one beam abut with the bricks hung from said one side of said one beam; and also abut similar bricks in a third course hung from flange means of a third arch beam. The bricks thus hung from and held down by the arch beams cooperate to maintain each brick in complete engagement with its corresponding beam and with each other. Thus, the bricks are in effect key-locked together by interengagement with each other and the arch beams.

The described advantages and features of the improved construction cooperate to achieve further all important advantages and results. Because of the simplicity of the construction, the minimum number of parts required, and the elimination of form erection and removal, a furnace is only down or out of opeartion about one-half of the time heretofore required to rebuild a roof. Thus, furnace tonnage can be increased by the amount of down time saved.

Furthermore, aside from actual brick cost which may be assumed to be the same for any roof regardless of construction, because of the reduced labor and materials costs, and because of the time saved in rebuilding, all of which characterize the improved construction, the material and labor costs for any roof constructed in accordance with the invention are approximately one-third of similar costs for prior basic open hearth roof constructions.

In addition to the foregoing, the entire roof asembly may be cooled, if desired, either by water or forced air passed through conduits formed in the arch beams, to achieve the benefits accompanying a cooled furnace roof, including a longer roof life.

Accordingly, it is a general object of this invention to provide a new basic open hearth roof construction which may be installed readily at a minimum cost and with a minimum number of parts.

it is another object of this invention to provide a new basic open hearth roof construction which includes arch beams at spaced intervals to which each roof brick is separately attached and by which each arch course of bricks is held in a permanent, fixed, arched position.

It is another object of this invention to provide a new basic open hearth roof construction including a plurality of spaced arch beams to which each brick is held fixed by direct abutment between each brick and beam, and by which each arch course of bricks is held permanently in place against upward expansion which would otherwise result due to the heat of the furnace.

It is another object of this invention to provide a new basic open hearth roof construction in which the bricks in each arch course are held down in side-to-side wedge abutment with each other to avoid breaking and spelling of the brick which could otherwise result from the brick rising out of abutment and into pinched engagement at their lower ends.

It is another object of this invention to provide a new basic open hearth roof construction utilizing unnotched, metal-encased, basic brich with integral hanger members by which the brich are individually and separately secured and held fixed in place on the flange of an arch beam in erecting the roof without the necessity of install ing temporary arch forms for roof erection.

It is another object of this invention to provide a new basic open hearth roof construction in which the bricks of one arch course are separately secured in place on one arch beam and in which the bricks of an adjacent arch course are similarly secured so that edge abutment between bricks of adjacent courses hold such bricks in place.

It is anoher object of this invention to provide a new basic open hearth roof construction including spaced arch beams which hold each course of bricks in fixed position by holding up and holding down each arch course of bricks.

It is another object of this invention to provide a new basic open hearth roof construction in which spaced arch beams are provided with reinforcing tube means by which the furnace roof may be cooled by passing coolant fluid through the tube means.

Also it is an object of this invention to provide a new basic open hearth roof construction utilizing only two different wedge-shaped, unnotched, metal-encased, preferably internally reinforced, basic roof brick with lntegral hangers and with hanger location being the only difference between the two different brick.

In addition, it is an object of the present invention to provide a new basic open hearth roof construction in which burn-off of the flame exposed surfaces of the erected roof does not cause excessive deterioration of the roof, or spalling and dropping out of portions of individual brick.

Likewise, it is an object of the present invention to provide a new basic open hearth furnace roof construction which may be readily and easily patched with a minimum of time and expense, and which may be erected to rebuild a furnace roof in substantially one-half the elapsed furnace down time heretofore required in rebuilding basic open hearth furnace roofs.

Finally, it is an object of the present invention to provide a new basic open hearth furnace roof construction which accomplishes the foregoing objects and desiderata in a simple, effective and inexpensive manner.

These and other objects and advantages, apparent to those sldlled in the art from the following description and claims, may be obtained, the stated results achieved, and the described difliculties overcome, by the apparatus, constructions, arrangements, combinations, subcombinations, elements, parts, and principles, which comprise the present invention, the nature of which is set forth in the foregoing general statements, preferred embodiments of whichillustrative of the best modes in which applicants have contemplated applying the principlesare set forth in the following description and shown in the drawings, and which are particularly and distinctly pointed out and set forth in the appended claims forming part hereof.

In the drawings which illustrate the new roof construction diagrammatically:

FIG. 1 is a fragmentary perspective view of a roof of an open hearth furnace constructed in accordance with the invention showing the manner in which the basic brick are separately attached in place directly to arched support beams;

FIG. 2 is an enlarged fragmentary perspective view showing one embodiment of the bricks and the manner in which they are assembled;

FIG. 3 is a perspective view of an unnotched, metalencased, wedged basic open hearth brick of regular construction having metal integral hanger members and used in the improved roof construction;

FIG. 4 is a perspective view of a generally similar key brick having differently located hanger means used to complete and lock each arch course of brick;

FIG. 5 is a perspective view of a fusion plate which is installed at spaced intervals of three or more bricks in each course and spanning two adjacent courses;

FIG. 6 is a fragmentary perspective view showing the manner in which the key bricks are locked in place in the various arch courses;

FIG. 7 is a diagrammatic view showing the manner in which a water coolant system for the roof may be in stalled in conjunction with -a coolant system for furnace doors and door frames;

FIG. 8 is a plan view showing the manner in which the ends of adjacent arch beams are bolted in place;

FIG. 9 is a vertical sectional view taken on the line 99 of FIG. 8; and

FIG. 10 is a fragmentary elevational view of a portion of the flame exposed ends of the roof brick after some burn-off has occurred.

Similar numerals refer to similar parts throughout the several figures of the drawings.

In FIG. 1 a roof 1 is generally indicated as a basic roof for an open hearth furnace in conneciton with which the invention will be described in detail. However, it is understood that the improved construction may be used for the roof of any other metallurgical furnace. The roof 1 includes a plurality of adjacent arched courses 2 of bricks 3. Each course of bricks includes a plurality of similar regular wedge bricks 3 which are separately attached to an arched support beam 4. A plurality of beams 4 are disposed at longitudinally spaced intervals across the top of the furnace roof 1 and have ends secured at front and back walls in a similar manner.

For example, as shown in FIG. -l, the courses 2 of bricks 3 rest upon skew brick 5 which rest upon a front wall 6 and similarly on the back wall (not shown) of the furnace. In addition, the lower front ends of the arched beams 4 are fixedly attached to the upper flange 7 of a channel member 8 above the skews 5. The bricks 3 in courses 2 are solely, individually, and directly supported by the spaced beams 4 and do not depend upon any other furnace supporting or reinforcing member for their support, such as furnace superstructure 9.

As shown in FIG. 3, each regular brick 3 is composed of a solid, unnotched block, internally plated or reinforced if desired, of refractory material 10, such as magnesite, contained within a metal casing -11 on the sides 11a and edges 11b of the brick. The upper and lower ends of the brick as shown are not encased. In addition, the casing 1 1 is provided with two hanger members or hooks 12 projecting upward from the sides 11a of the brick, which are preferably integral with the casing 11. However, the hangers 12 may be separate metal pieces secured to the casing as by welding, where the hooks 12 cannot be fabricated readily as integral parts of the casing 11.

The brick 3 has a wedge shape with the upper end between sides 11a thicker than the lower end so that when placed together the bricks form the arched courses 2 as shown in FIG. 1. Although the bricks 3 are preferably provided with two hooks as shown in FIG. 3, the bricks may include only one hook 12, such as shown in FIG. 1. Two hooks '12 are preferred to enable placement of each brick 3 in a balanced position on the beam 4 although one book is suflicient for holding a brick in place The manner in which the bricks 3 are attached to .the arch beams 4 is more particularly shown in FIG. 2, in which each beam 4 is composed of a tubular member or pipe 13 having an inverted T-beam 141 secured to the undersurface of the member '13, such as by welding. In the alternative, the beam '4 may comprise an H- or I- beam preformed to the radius of the desired arch.

In FIG. 2 each regular brick 3 is secured by the hooks 12 to a flange 15 extending from one of the opposite sides of the axis of the beam 4. In that manner the bricks in adjacent courses abutting each other between each pair of beams 4 hold each other in place to prevent them from slipping out of hooked engagement with the flanges 15. A new roof is preferably installed by inserting the bricks in the space between the beams 4 and engaging the hooks 12 over a flange 15 as shown in the drawings.

Installation of each course of bricks starts from opposite skews of which only the front skew 5 is shown, and continues upwardly to the center of the arch where, because of space limitations, one or more key bricks 16 (FIG. 4) are placed. The Wedge key brick 16 is similar in all respects to the regular wedge brick 3 except that the key brick is provided with a single hanger member or hook '17 extending upwardly from one edge 11b of the brick rather than from one or both sides 11a of the brick 3, as shown in FIG. 3. By such construction the key brick 16 may be laterally inserted into place without the necessity of sliding the key bricks both longitudinally and transversely of the beams 4 as is necessary for hanging the wedge bricks 3 in place. With the regular Wedge brick 3 additional room is needed for inserting the brick laterally to engage the hangers 12. with a beam flange 15 and then sliding the hooks 12 into place along flange 15.

However, the key bricks 16 may be inserted by sliding laterally into place and when in place a short rod 18 is inserted beneath the books 17 with opposite end portions of the rod resting upon the flanges 15 of adjacent beams 4. As shown in FIG. 1, a number of key bricks 16, such as three or more, may be installed in each arch course, preferably at the center or uppermost portion of each course 2 of bricks.

Each course 2 of bricks is provided with a plurality of fusion plates 19 which are situated as shown in FIG. 1, at spaced intervals preferably of three bricks, although any desired fusion plate spacing may be used, depending upon the furnace design, size, operating conditions, etc.

The fusion plate 19 preferably includes a lower rectangular portion which is disposed between the bricks 3, having a length equal to the length of the brick 3 and a width equal to the width of two bricks 3. In addition, the plate 19 includes an upper fin portion 20 of substantial area separated from the lower portion of the plate by oppositely inwardly extending siots 2.1. The fin portions above the slots serve as books for engaging oppositely disposed flanges I15 of two adjacent beams 4 (FIG. 2). The fusion plates 15 are formed of much heavier gauge metal than the gauge of the brick casing metal. Thus the thick fusion plates 19 conduct heat outwardly from the bricks to the fin portions 20 and arch beams 4 which dissipate the heat into the atmosphere above the roof.

The plates 19 also serve a purpose of facilitatiing expansion of flame exposed ends of the brick 3 by minimizing the effect of such expansion. As shown in FIG. 10, the bricks 3 when the roof is erected have original lower flame exposed end surfaces indicated by the dot-dash line 22. After the furnace has been heated and in operation at temperatures above 3000" F. and usually at 3100- 3250" -F., the flame exposed refractory material ends of the brick 3 may burn oif or burn back somewhat as indicated in full lines in FIG. at 23. At the same time, the inner ends of the individual metal casing for the brick mayburn back further, between adjacent bricks,than the refractory burn-off, as indicated in full lines at 23a in FIG. 10. Similarly, the thicker metal fusion plates may burn back further than the refractory burn-off, as indicated at 23!) in FIG. '10.

This burn-off or burn-back of both refractory material and metal at the flame exposed surface of the roof is accompanied by a rearrangement of the components and complex reactions under the high operating temperatures involved.

Reactions between iron oxide originating from the metal of the metal casings and metal fusion plates and from the furnace atmosphere, and the brick refractory material may cause a swelling or expansion of the inner, hotter ends of the brick at and adjacent the flame exposed surfaces, as indicated at 24 in FIG. 10. In prior constructions, such swelling as well as the high expansion rate of basic brick sometimes resulted in a build-up of crushing pressures between the lower ends of the brick longitudinally of each arch course, which contributed to an increased spalling effect.

However, in the improved construction of the invention, with the heavy fusion plates located as described, the spaces left (see 241: between dot-dash lines indicating spaces occupied by plates 19 before burn-elf) in zones where there has been fusion plate burn-back, at intervals along each arch course of brick, provide space for swelling 24 of the flame exposed and burnt-back brick refractory material ends. Thus there is no build-up of damaging, crushing forces incident to swelling or expansion of the refractory at the flame exposed ends of the brick and spalling thereof is substantially reduced, the surfaces fusing to form a hard, efficient, integrated, flame exposed surface.

These swelling and expansion problems encountered in the use of basic brick for open hearth furnace roofs heretofore have presented difliculties that have not been eliminated in prior attempts to provide all-basic brick roofs in metallurgical furnaces, and particularly for open hearth furnaces where very high temperatures of operation are involved.

The roof construction of the present invention solves the long-existing problems of expansion in an all-basic brick open hearth furnace roof in the manner described.

Where no means are provided to prevent expansion of an arch course of basic brick, as the lower end portions of the brick expand, the bricks tend to rise upward, and the upper portions of the brick necessarily move out of contact with each other, leaving a wedge-shaped space usually between each pair of bricks. Simultaneously the entire arch course heaves upwardly out of its original shape and location. As a result, the weight 'of the load of the entire arch course is borne by relatively small end portions of expanded brick which, being weaker at the higher temperature of operation of the furnace, crack and spell 01?. This process continues until entire bricks drop out and the roof ultimately fails.

As shown in FIG. 2, the upper ends of each brick 3 are in flat surface abutment with the undersides of the flanges E5 of the l-beams l4; and, as shown in FIGS. 1, 8, and 9,

the opposite ends of the beams 4 are secured by the bolts 25 to the channel members 8 so that each beam 4 is held in place. Thus it is impossible for the bricks themselves or the arched courses 2 of bricks 3 to rise due to any expansion of the lower end portions of the bricks, as was the case heretofore in prior basic brick roofs. Thus the bricks are held in complete surface-to-surface contact between their wedge sides lla with each other.

The fusion plates 19 cooperate with the beams 4 to prevent the arch courses 2 of bricks 3 from heaving or swelling upwardly. As indicated, the lower ends of the fusion plates 1% melt away and recede upwardly at a faster rate than the bricks 3, thereby providing space into which the lower end portions 24 of the bricks may swell or expand.

The beams 4 perform the double function of holding up and holding down each individual brick. Moreover, if for any reason, one or more bricks should drop out of place, each of the remaining bricks is held in place separately by the hooks 12 as well as by the edge-to-edge abutment between adjoining bricks in adjacent courses.

The beams 4 are each rigid members composed of a durable material such as steel and each has a shape of a tube over an inverted T-beam as shown in the drawings, or of an H-beam or an l-beam of suitable height. Where the beam 4 has the configuration shown in the drawings including a tubular member or pipe 13, the beam 3 not only has a rigid structure but the pipe 13 provides a passage for fluid cooling means for each beam as well as for adjacent bricks 3 and fusion plates 19.

When the roof is installed each beam i is placed in position and secured in place by the bolts 25 at each end. For receiving the bolts 25, each end of the beam preferably is provided with an angle member 26 having a bolt slot 27 (FIG. 8) extending transversely to the axis of the beam 4. Bolt slots 23 are also provided in the upper flange 0f the channel members 3, which slots extend perpendicular to the slots 27 in the angle members 26. This arrangement of slots 27-28 permits the ends of the arch beams 4 to come and go incident to expansion and contraction of the beams as the furnace is heated and cooled.

As shown in FIG. 7, the tubular portion 13 of the beams 4 may be connected with a water coolant system by providing interconnecting conduits 29 at the rear ends of the beam 4; and by providing conduits 3t} and 3-1 connected with the conventional water cooling means for an open hearth door 32 and 'door frame 33. In the alternative, the pipe 13 may be used as an air-conducting conduit for an air cooling system rather than for a water cooling system.

Accordingly, the present invention provides a basic brick roof construction for open hearth furnaces that eliminates prior art difficulties by providing means for not only holding up the brick separately and individually but also for holding down each individual brick and for preventing arch courses of basic brick from rising due to expansion which occurs at elevated temperatures.

Shch means also includes the rigid arch beam, the opposite ends of which are secured in place on opposite sides of the furnace. With each brick individually attached to a beam and with the upper end surface of each brick in abutment with the undersurface of the beam, the bricks during any tendency of expansion are maintained in their original position. Moreover, the means includes the fusion plates which not only dissipate heat from the surfaces of the bricks but also upon burn-off provide expansion or swelling space for the flame exposed end portions of the brick.

In addition, the arched beam may be provided with either water or air cooling means that may or may not be used in conjunction with the typical water cooling system for the doors and door frames of open hearth furnaces.

Furthermore, the new basic brick roof construction provides for the installation of a new roof at a minimum of expense because of the elimination of the need for temporary forms for holding the bricks in the proper arch location during erection, as well as the elimination of the need for skilled brick masons, because the improved construction may be installed by relatively unskilled labor.

Other important aspects of the invention are the use of unnotched, metal-encased, wedged basic brick with hangers integral with the casing, and the cooperative relation thereof to the arch beams which hold each brick down and from which each brick hangs. The unnotched character of each brick provides a solid refractory body of maximum strength, eliminating the weakness introduced into the refractory material of prior basic open hearth furnace roof brick by notches or cavities always present in prior constructions.

Further, since each brick is suspended through its casing and held down by top end abutment with the arch beam, the dead weight of each brick is supported by the wedge shape of its casing and not through the body of the refractory material itself. Thus each brick is supported and held in fixed position in its arch course without introducing any tensional stresses in the refractory body of the brick.

Also, during burn-off of the flame exposed ends of the brick, brick casing material and fusion plates, and the complex reactions occurring, there may be some bonding, welding or fusion between any two or all of the refractory material, metal casing material and fusion plates, which, coupled with the wedge shape of each brick casing tend to hold the refractory material intact, even though some spalling or cracking of the refractory material may be initiated. These characteristics of the improved construction, coupled with the space accommodation for swelling during burn-off provided by the heavy metal fusion plates, result in a minimum of deterioration, spalling, cracking and dropping out of refractory material at the flame exposed surface of the roof during high temperature furnace operation and heating and cooling periods.

The description of the improved open hearth roof construction is by way of example and the scope of the invention is not limited to the exact details illustrated or to the specific sizes of brick, fusion plates and roof shown, or to the particular refractory composition of the basic brick described, since these details, sizes and composition may be varied to suit the conditions or specifications of any particular furnace involved.

Having now described the features, discoveries and principles of the invention, the construction and operation of the new basic brick open hearth furnace roof, and the advantageous, new and useful results obtained thereby; the new and useful apparatus, constructions, arrangements, combinations, subcombinations, elements, parts, principles and discoveries, and mechanical equivalents obvious to those skilled in the art are set forth in the appended claims.

What is claimed is:

1. In an all basic furnace roof, a series of spaced bricksupporting and hold-down beams extending over the furnace and having opposite ends secured to opposite side walls of a furnace, a series of adjacent courses of solid,

unnotched, basic material bricks, each brick having a metal casing for the four sides of the basic material of said brick, the casing being provided at its upper end with at least one beam-engaging hook, the hook being secured directly to one of the beams, each hook projecting upward from the side of the brick and being integral with the casing, each hook being .engageable with and disengageable from one side of the beam, the series of courses of bricks being grouped in pairs of adjacent courses in which all of the bricks of one pair of courses are secured to one beam and all of the bricks in an adjacent pair of courses are secured to an adjacent beam, the bricks in one course of a pair of courses being in edge-to-edge surface abutment at one edge with edges of bricks in the adjacent course of the pair of courses, the bricks in said one course also being in edge to-edge surface abutment at another edge with edges of bricks in another adjacent course of another pair of courses, each beam having an undersurface of substantial area extending in opposite directions from a plane passing through said edge-to-edge surface abutment of bricks in a pair of courses, the upper end of each brick in each course being engaged in suriface-to-surface abutment with the undersurface of the beam to which the brick is secured, and said edge-to-edge surface abutment of the bricks in a course of one pair of courses with bricks in a course of another pair of courses holding said bricks in hooked engagement with the beams to which the bricks are secured, whereby each brick in every course is held down in position by its surface-to surface abutment with the undersurface of the beam to which the brick is secured.

2. The construction defined in claim 1 in which the undersurface of each beam is in substantial horizontal alignment at any section with the undersur face of the adjacent beams.

3. In an all-basic furnace roof arch, a series of spaced arched brick-supporting and holddown beams extending over the furnace and having opposite ends secured to opposite side walls of the furnace, a series of arched courses of solid .unnotched basic material wedge bricks, each brick in any course having a metal casing for the four sides of the basic material of said brick, the casing being provided at its upper end with at least one beamengaging hook, each beam having a center web portion and having flanges extending horizontally in opposite directions from the web portion, said flanges having an undersurface of substantial area, the beam-engaging hook of each brick being directly secured to and on one side of a flange of the beam, the series of courses of bricks being grouped in pairs of adjacent courses in which all of the bricks of one pair of courses are secured to one beam and all of the bricks in an adjacent pair of courses are secured to an adjacent beam, the bricks in one course of a pair of courses being in edge-to-edge surface abutment at one edge with edges of bricks in the adjacent course of the pair of courses, the bricks in said one course also being in edge-to-edge surface abutment at another edge with edges of bricks in another adjacent course of another pair of courses, the upper end of each brick in each course being engaged in surface-to-surface abutment with the undersurface of the beam to which the brick is secured, and said edge-to-edge surface abutment of the bricks in a course of one pair of courses with bricks in a course of another pair of courses holding said bricks in hooked engagement with the flanges, where- 1 1 by each course of bricks is held down in place against upward movement by the beam during furnace operation.

4. In an all-basic furnace root, a series of spaced brick hold-down beams extending over the furnace and having opposite ends secured to opposite side Walls of a furnace, a series of adjacent courses of solid, unnotched, basic material bricks, each brick having a metal casing for the four sides of the basic material of said brick, the series of courses of bricks being grouped in pairs of adjacent courses, the bricks in one course of a pair of courses being in edge-to-edge surface abutment at one edge with the edges of bricks in the adjacent course of the pair of courses, the bricks in said one course also being in edgeto-edge surface abutment at another edge with edges of bricks in another adjacent course of another pair of courses, each brick in a given course having a beam-engaging hook extending above and integral With the easing and being engageable with and disengageable from one side of the beam, each beam having an undersurface of substantial area extending in opposite directions from a plane passing through said edge-to-edge surface abutment of bricks in a pair of courses, the upper end of each brick in each course being engaged in surface-.to-surface abutment with the undersurface of its corresponding 12 beam, and said edge-to-edge surface abutment of the bricks in adjacent courses holding the bricks in lateral alignment with their corresponding beams, whereby each brick in every course is held down in position by its sur tace-to-surface abutment with the undersurface of its corresponding beam.

References Cited in the file of this patent UNITED STATES PATENTS 1,463,240 Biglow July 31, 1923 1,472,945 Strachota Nov. 6, v1923 1,896,769 Davis et a1 Feb. 7, 1933 1,948,093 Baird et al Feb. 20, 1934 2,781,006 Heuer Feb. 12, 1957 2,930,601 Heuer Mar. 29, 1960 2,932,265 Heuer Apr. 12, 1960 3,005,423 Longenecker Oct. 24, 1961 3,005,424 :I-Ieuer Oct. 24, 1961 FOREIGN PATENTS 523,620 Italy Apr. 18, 1955 938,265 Germany Jan. 26, 1956 1,014,200 France 'May 28, 1952 1,072,449 France Mar. 17, 1954 1,187,813 France Mar. 9, 1959

Claims (1)

1. IN AN ALL BASIC FURNACE ROOF, A SERIES OF SPACED BRICKSUPPORTING AND HOLD-DOWN BEAMS EXTENDING OVER THE FURNACE AND HAVING OPPOSITE ENDS SECURED TO OPPOSITE SIDE WALLS OF A FURNACE, A SERIES OF ADJACENT COURSES OF SOLID, UNNOTCHED, BASIC MATERIAL BRICKS, EACH BRICK HAVING A METAL CASING FOR THE FOUR SIDES OF THE BASIC MATERIAL OF SAID BRICK, THE CASING BEING PROVIDED AT ITS UPPER END WITH AT LEAST ONE BEAM-ENGAGING HOOK, THE HOOK BEING SECURED DIRECTLY TO ONE OF THE BEAMS, EACH HOOK PROJECTING UPWARD FROM THE SIDE OF THE BRICK AND BEING INTEGRAL WITH THE CASING, EACH JOOK BEING ENGAGABLE WITH AND DISENGAGEABLE FROM ONE SIDE OF THE BEAM, THE SERIES OF COURSES OF BRICKS BEING GROUPED IN PAIRS OF ADJACENT COURSES IN WHICH ALL OF THE BRICKS OF ONE PAIR OF COURSES ARE SECURED TO ONE BEAM AND ALL OF THE BRICKS IN AN ADJACENT PAIR OF COURSE ARE SECURED TO AN ADJACENT BEAM, THE BRICKS IN ONE COURSE OF A PAIR OF COURSES BEING IN EDGE-TO-EDGE SURFACE ABUTMENT AT ONE EDGE WITH EDGES OF BRICKS IN THE ADJACENT COURSE OF THE PAIR OF COURSES, THE BRICKS IN SAID ONE COURSE ALSO BEING IN EDGE-TO-EDGE SURFACE ABUTMENT AT ANOTHER EDGE WITH EDGES OF BRICKS IN ANOTHER ADJACENT COURSE OF ANOTHER PAIR OF COURSES, EACH BEAM HAVING AN UNDERSURFACE OF SUBSTANTIAL AREA EXTENDING IN OPPOSITE DIRECTIONS FROM A PLANE PASSING THROUGH SAID EDGE-TO-EDGE SURFACE ABUTMENT OF BRICKS IN A PAIR OF COURSES, THE UPPER END OF EACH BRICK IN EACH COURSE BEING ENGAGED IN SURFACE-TO-SURFACE ABUTMENT WITH THE UNDERSURFACE OF THE BEAM TO WHICH THE BRICK IS SECURED, AND SAID EDGE-TO-EDGE SURFACE ABUTMENT OF THE BRICKS IN A COURSE OF ONE PAIR OF COURSES WITH BRICKS IN A COURSE OF ANOTHER PAIR OF COURSE HOLDING SAID BRICKS IN HOOKED ENGAGEMENT WITH THE BEAMS TO WHICH THE BRICKS ARE SECURED, WHEREBY EACH BRICK IN EVERY COURSE IS HELD DOWN IN POSITION BY ITS SURFACE-TOSURFACE ABUTMENT WITH THE UNDERSURFACE OF THE BEAM TO WHICH THE BRICK IS SECURED.

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