Patent Publication Number: US-3877402-A

Title: Suspended crowns of industrial furnaces, and refractory elements for making such crowns

Description:
United States Patent [191 Palazzo SUSPENDED CROWNS OF INDUSTRIAL FURNACES, AND REFRACTORY ELEMENTS FOR MAKING SUCH CROWNS [75] Inventor:  
 [73] Assignee: S.I.R.M.A. Societa Italiana Refrattari Marghera Azionaria, Venice, Italy 22 Filed: Mar. 8, 1974 21 Appl. No.: 449,424  
 Ferdinando Palazzo, Venice, Italy [30] Foreign Application Priority Data Mar. 22, 1973 Italy 67821/73 [52] U.S. Cl. 110/99 R; 432/247 [51] Int. Cl. F23m 5/02 [58] Field of Search 110/99 R, 99 A; 432/247 [56] References Cited UNITED STATES PATENTS Liptak ll0/99 R [451 Apr. 15, 1975 1 H1953 Forsyth 110/99 R 10/1962 l-Iosbein et a]. 110/99 R Primary Examiner--.Iohn .I. Camby Attorney, Agent, or Firm-Breitenfeld &amp; Levine [57] ABSTRACT A suspended crown of an industrial furnace formed of anchored refractory bricks, additional refractory bricks, and refractory plates. The anchored bricks are formed at one end with means for engaging hooks which secure the bricks to support beams, and at their opposite ends with shoulders for carrying the refractory plates. The sides of the anchored and additional bricks are formed with teeth which mesh with teeth in adjacent bricks. The plates are generally rectangular and provided with parallel channels for reducing their weight.  
 6 Claims, 18 Drawing Figures PATENTEDAPRISIQYS SHEET ug g SUSPENDED CROWNS OF INDUSTRIAL FURNACES, AND REFRACTORY ELEMENTS FOR MAKING SUCH CROWNS The present invention relates to improvement concerning the suspended crowns of industrial furnaces, and refers specifically to refractory elements intended to form said crowns.  
 The use of suspended crowns formed by refractory bricks having a particular shape is known. Some of the bricks are hooked to load bearing beams, while others are so shaped as to permit assembly with each other and with the first mentioned bricks in order to form partially self-supporting crown assemblies.  
  It is also known that in the design of the suspended crowns the thermal expansions of the elements used must be taken into account, as said elements are not only subject to premature wear but, although they are made with a suitable and accurately selected material, they are also subject to possible breakages, flaws, and cracks deriving from the internal stresses cuased by the thermal effect to which the structural elements are subjected.  
  The main object of the present invention is to provide, as a new industrial product, suspended crowns for industrial furnaces in general, which can be quickly assembled and formed by modular elements easily replaced in the case of damage or wear.  
  Another object of the invention is to prrovide suspended crowns formed by bricks combined with refractory plates, the latter having a special surface and being therefore suitable for rapid construction of suspended crowns, even of great expanse.  
  With the aforesaid objects in view, the improvement according to the invention is substantially characterized in that the suspended crown structure comprises three basic modular elements, that is:  
  a. Anchored refractory bricks, substantially prismatic and provided at one end with holding means for metal hooks engaged with load bearing beams, while the opposite end is so shaped as to provide small bearing shoulders for refractory plates; the pair of opposed sides of said bricks being respectively provided with symmetrical grooves and teeth;  
  b. Refractory bricks which are complementary and analogous to the anchored bricks, but not provided with holding means for hooks; and  
  c. Refractory plates having a substantially rectangular shape in plan and a pair of parallel sides so shaped as to form bearing edges, with respect to the brick shoulders, and ordered in parallel rows, while the other pair of parallel sides are cut along slanting planes parallel to each other; the body of each plate being crossed by parallel channels forming wide weight-reducing hollow spaces.  
  According to a structural variant, while keeping the anchored refractory bricks unchanged, the order of complementary refractory bricks may be eliminated, while the plates assume, in this case, preferably a plan shape with a square outline and rest, by ledge seats formed at their four vertices, on the anchored brick shoulders.  
  Another feature according to the present improve ment derives from the structure of the refractory plates which, in any case, is box-shaped and hence made stiff in order to be sturdier and at the same time lighter in weight.  
  A further feature of the improvement derives from the open structure shape, substantially with a U outline, of the metal hooks which anchor each refractory brick with respect to the load bearing beams; the shape of said hooks being the most rational to co-operate with said anchored bricks, as it will be described Additonal particular features of the invention will be seen from the specification and the drawings, which are annexed only for an illustrative purpose, and wherein:  
  FIG. 1 represents a furnace provided with a crown according to the invention, in a vertical cross sectional view;  
  FIG. 2 is a partial vertical cros sectional view of the furnace crown alone, along line 11- of FIG. 1;  
 FIG. 3 is a top plan view of same crown;  
 FIG. 4 is a plan view of a refractory plate;  
 FIG. 5 is an end view of same plate of FIG. 4;  
 FIG. 6 is a side view of the end of the same plate;  
  FIGS. 7 and 8 are elevational views, rotated to each other, of a first shape of an anchored refractory brick;  
  FIGS. 9 and 10, similar to the preceding two figures, illustrate a variant of some details of said brick;  
  FIGS. 11 and 12 are side views of a complementary brick;  
  FIG. 13 is a perspective view of an anchoring hook for the bricks according to FIGS. 7 to 10;  
  FIG. 14 is plan view of a refractory plate according to a variant;  
  FIG. 15 illustrates the same plate inverted through FIG. 16 is a side view of the plate of FIGS. 14 and 15;  
  FIG. 17 illustrates schematically and in a plan view the assembly of a plate of FIGS. 14 to 16; and  
 FIG. 18 is a side elevation view of a detail of FIG. 17.  
  With reference to FIGS. 1, 2, and 3, the furnace port, defined by the floor A and side walls B of suitable masonry, is at the top defined by the suspended crown according to the invention, which comprises a plurality of iron beams 20 with respect to which refractory bricks 22 (FIGs. 2, 3, 7, 8, 9, 10) are suspended by means of hooks 21.  
  Each, substantially prismatic, brick 22 is provided, at one of its ends 22a, with symmetrical and opposed projections 22b forming angled seats, with an acute angle, suitable to retain the horizontal branch 21a of a substantially U outlined hook 21. Ends 21b of a pair of hooks 21 used for each brick 22 or 23, engage the side edges 20a (FIGS. 1 and 2) of the lower flange of each beam 20. The end 22d of each brick 22 or 23 has a T- shaped outline and with its side projections 22d, forms horizontal bearing brackets for the edges 24a of refractory plates 24.  
  According to a first variant, FIGS. 7 and 8, the upper end 23a of each brick, instead of the symmetrical projections 2211, presents an inverted T-shaped cut 2317 which forms a hollow seat for a pair of hooks 21 engaging, as described, the lower flange of beam 20.  
  Each refractory brick 22 and 23 having its central part shaped as a retangular prism, is provided, on the sides at right angles with respect to those terminatng with the side projections 22d, respectively, with symmetrical grooves 22e, 232, and teeth 22f, 23f.  
  Refractory bricks 25 (FIGS. 11 and 12) cooperate with bricks 22, 23, and present a lower end 25a having the T-shaped outline as the one already described; the  
 sides provided with grooves 25c and teeth 25f but without retaining means for the hooks 21.  
  Courses of bricks 22, 25 are mounted in side-by-side rows directly under beams 20, as represented on FlGS. 1, 2, and 3.  
  Bricks 23 are anchored and they are easily and rapidly hooked to beams forming, with parallel beams, the load bearing framework for the suspended crown; two or more of the bricks 25, mutually fixed along the sides and fixed with respect to the cooperating quoins 23, are partially self-supporting. The order of the two cooperating quoins form opposed and symmetrical bearing brackets 22d for the ledge edges 24a of plates 24 of refractory material.  
  Each plate 24 (FIGS. 4, 5, 6) has a box-shaped body, namely, a body provided with wide channels 24d which reduce its weight while providing the assembly with a remarkable stiffness. Each plate 24 further presents end edges 240 at 90 with respect to the toothed edges 24a cut with a slanting outline in order to permit assembly by coupling of the edges with the preceding and fol lowing plates.  
  The toothed outline 24a of the plates, which rest on brackets 22d of bricks, and the slanting outline, with the broken line 24c, 24d of same plates reduce appreciably, if they do not eliminate, the thermal losses by blow-by of the furnace. The channels 24b of said plates create further hollow spaces which are useful for the thermal insulation of the crown and to admit in said channels the smoke from the burners of the furnace to obtain direct heating of the crown.  
  According to the structure of the suspended crown, and retaining the use of the bearing bricks 22 or 23 and the framework of beams 20 unchanged, the refractory plates 26 may be made with a preferably quadrangular plan shape structure, with angles at the vertices 26a cut at right angles, as represented in FIGS. 14 to 17. In such case, with the eleimination of the intermediate bricks 25, the suspended crown of the furnace assumes a more compact structure which is less subject to movement; the bearing bricks 22 or 23 are provided at their lower ends with a head 23g having four bearing edges.  
  The refractory plates 26 are provided with ribs 26b weight-reducing cavities 26c. They further present parallel edges 26:] profiled with opposed teeth so that the perimetrical edges of each plate 26 may be overlapped with respect to the edges of the preceding and following plates in a horizontal plane.  
  Obviously, in both the case of plates 24 and the case of plates 26 the respective rectangular plan shape and quadrangular plan shape is preferred but not limiting, in that it may vary according to the extension of the crown and, hence, to the furnace capacity.  
  In both the described cases the particular features of the suspended crown remain; said features have already been mentioned and are summarized as follows:  
  crown formed by three or two pressed modular elements;  
  rapid assembling of the crown due to the rapid and easy assembly of the elements which form it;  
  hooks to retain the bearing bricks and having .a U shaped profile, namely, open and hence easily disengageable from the corresponding hook seats formed by the lower flange of the beams;  
  a compact structure of the crown which prevents es cape of heat;  
  the crown may be heated by the use of plates 24 of the type illustrated on FIGS. 4, 5, and 6, that is, provided with channels 24b which are coincident between the various plates of each course included between two parallel beams 20;  
  savings in construction deriving from the use of modular elements and the rapidity of assembling and possible replacement of same.  
  Obviously, the improvement according to the invention is not limited particularly to the embodiments represented and described herein only for illustrative purposes, but it comprises all the variants depending from the described solutions and the improvements which may necessarily or advantageously result from the practical application.  
 What is claimed is:  
  l. A furnace crown suspended from parallel fixed beams, said crown comprising:  
 a. hook-shaped anchors adapted to engage the flanges of the beams and depend therefrom,  
 b. a plurality of anchored refractory bricks, of generally rectangular cross-sectional shape, spaced apart along the length of each beam, each anchored brick being formed at its upper end with means for accommodating said anchors and at its lower end with flanges projecting from two opposite sides of said anchored brick, the other opposite sides of said anchored brick each being formed with horizontally extending grooves and projections,  
 c. a plurality of non-anchored refractory bricks, of generally rectangular cross-sectional shape, each being devoid of means at its upper end for accommodating said anchors, each of said non-anchored bricks being formed at its lower end with flanges projecting from two opposite sides of said brick, the other two opposite sides of said non-anchored brick each being formed with horizontally extending grooves and projections, at least one of said non-anchored bricks being arranged between each two successive anchored bricks with the grooves and projections of the non-anchored brick intermeshed with the grooves and projections of bricks on each side of the non-anchored brick to thereby form parallel rows of bricks, and  
 d. a plurality of generally rectangular refractory plates each extending between two of said rows of bricks, the ends of each plate resting upon the projecting flanges of said bricks.  
  2. A furnace crown as defined in claim 1 wherein each of said anchors is generally U-shaped so as to present a central horizontal portion, and said means for accommodating said anchors comprises a cavity, in the upper end of each anchored brick, having the shape of an inverted T, each end of the cross-member of the T being adapted to accommodate a horizontal portion of one of said anchors.  
  3. A furnace crown as defined in claim 1 wherein each of said plates is formed with through channels oriented in the direction of said rows of bricks, the plates between each two rows of bricks being arranged sideby-side with the channels in each plate communicating with the channels in the adjacent plates.  
  4. A furnace crown as defined in claim 1 wherein the sides of each of said plates at which said channels terminate are slanted with respect to the upper and lower faces of the plate, the ends of each plate which rest upon said brick flanges being of stepped configuration.  
  6 5. A furnace crown suspended from parallel fixed brick, and beams, said crown comprising: 0. a plurality of generally rectangular plates, each a. hook-shaped anchors adapted to engage the plate extending between at least two of said bricks flanges of the beams and depend therefrom, and resting upon opposed flanges of the bricks beb. a plurality of anchored refractory bricks, of gener- 5 tween which it is located.  
 ally rectangular cross-sectionalshape,spaced apart 6. A furnace crown as defined in claim 5 wherein along the length of each beam, each anchored each corner of each of said plates is formed with a genbrick being formed at its upper end with means for erally rectangular notch for accommodating a portion accommodating said anchors and at its lower end of a brick above said flanges. with flanges projecting from all four sides of said 10