US3220367A

US3220367A - Divided taper brick

Info

Publication number: US3220367A
Application number: US177004A
Authority: US
Inventors: Joseph L Stein
Original assignee: General Refractories Co
Current assignee: General Refractories Co
Priority date: 1962-03-02
Filing date: 1962-03-02
Publication date: 1965-11-30
Anticipated expiration: 1982-11-30
Also published as: AT250848B; DE1872893U; GB985708A; NL133637C; NL289641A

Description

Nov. 30, 1965 J. L. STEIN 3,220,367

DIVIDED TAPER BRICK Filed March 2, 1962 2 Sheets-Sheet l 28 {JJ/Orior/' INVENTOR TORNEY Nov. 30, 1965 J. L. STEIN 3,220,367

DIVIDED TAPER BRICK 2 Sheets-Sheet 2 Filed March 2, 1962 VUnited States Patent O 3,220,367 DIVIDED TAPER BRICK Joseph L. Stein, Philadelphia, Pa., assignor to General Refractories Company, a corporation of Pennsylvania Filed Mar. 2, 1962, Ser. No. 177,004

1 Claim. (Cl. 11G-99) The present invention relates to refractory bricks of the type used in forming a working refractory lining such as an arch, roof, side wall or bottom of a metallurgical furnace, or a rotary kiln lining.

A purpose of my invention is to provide a composite refractory shape possessing increased wedging taper.

A further purpose is to produce a brick having a wedging taper or keying effect greater than that possessed by conventional standard brick shapes which form structures of the same general dimensions.

A further purpose is to prolong the lives of furnace brick when used in roofs and other linings by locking spalled sections' of the brick into the structure.

A further purpose is to prolong the life of furnace linings by locking bricks into the structure so they cannot become dislodged.

A further purpose is tol form a more stable arch, roof, side wall, end wall or iloor of a metallurgical furnace by locking the brick into the structure.

A further purpose 'is to allow the use of a lining of lesser thickness than similar linings of conventional shaped brick.

A further purpose is to create a keying effect in a flat wall or flat bottom of a metallurgical furnace.

A further purpose is to more securely lock the brick in a rotary kiln lining.

Further purposes appear in the specification and in the claims.

In the drawings I have chosen to illustrate several different mechanisms which may be used in carrying out the invention.

FIGURE 1 is an elevational section of a prior art arch.

FIGURE 2 is an elevational section of a prior art arch in which the outside radius of the arch is less than the outside radius of the arch of FIGURE 1.

FIGURE 3 is an end elevation of a prior art taper brick.

FIGURE 4 is a perspective view of the brick of FIGURE 3.

FIGURE 5 is an end elevation of a taper brick according to the invention.

FIGURE 6 is a perspective view of the brick of the invention.

FIGURE 7 is an end elevation of a modified form of the brick of the invention.

FIGURE 8 is a perspective view of a` solid rectangular block having the brick of the invention superimposed thereon.

FIGURE 9 is a fragmentary perspective view of the curved arch of the invention.

FIGURE l0 is an exploded perspective view of the curved arch of the invention from a position below the arch.

FIGURE 11 is an end elevation showing the brick of the invention for use in straight arches.

FIGURE 12 is a plan view of the brick of FIG- URE 1l.

FIGURE 13 is an end elevation of a flat arch of the invention.

FIGURE 14 is a perspective view of the brick of FIG- URE 6 having external metallic oxidizable metallic plates.

Describing in illustration but not in limitation and referring to the drawings:

Extensive use is made in lining metallurgical furnaces ACC with refractory brick using the arch principle. An arch is a structural member usually, but not necessarily, curved and made up of separate wedge shape solids with their joints at right angles to the curve. In metallurgical furnaces and the like, an arch is primarily used to support the Weight of the solids or bricks forming the arch so that an enclosure is formed as a working refractory lining.

In the present invention, an arch is considered to include both a curved and flat structure. In accordance with the present invention, the strengt of the arch to support vertical loads is increased in the case of curved arches without decreasing the radius of curvature of the arch, and in the case of a iiat span, the vertical forces are resolved into a diagonal thrust so that an increased span can be used. Furthermore, the present invention provides for interlocking the bricks of the arch together.

The brick of the invention is particularly applicable to lining rotary kilns used for the calcining of raw materials, for the production of cement klinker, and similar type of roasting operations. It will be seen that in a kiln of this sort the radius of curvature of the kiln is fixed by the outside plate structure and could conceivably be, for instance, of a 16 feet 6 inch diameter. These diameters have been constantly increasing and as seen in the general description above, the wedge angle of the prior art brick decreases as the diameter or radius of the kiln increases. This decrease in wedge angle results in many instances in a loose tting brick in the lining with subsequent development of trouble spots caused by falling brick.

According to the present invention, the radius of curvature of the brick lining which is determined by the diameter of the kiln is kept constant while the wedge angle of the brick is increased. This results in a strong interlocking lining which is desirable for trouble free operation. By virtus of the brick of the invention, rotary kilns can be increased in diameter far in excess of that which was permissible with a prior art taper brick, since the wedge angle of the present brick is increased over that of the prior art while at the same time maintaining the radius of curvature of the lining.

For instance, in an arch constructed according to t-he present invention, the same vertical thrust can be supported in an arch having approximatelytwo times the radius of curvature of a prior art arch' required to support the same vertical thrust. It is desirable to increase the radius of curvature while reducing the rise per foot of an arch in order to build a more compact metallurgical furnace or the like, and in order to reduce the weight of the arch.

In the construction of an arch, as the taper of a brick is increased, the normal to the taper. surface yields a greater vertical component. Considering that the vertical component is the force which holds the bricks up, and that the force normal to the taper is the force ultimately imparted by the bearing points of skewbacks of the arch, it is desirable to keep the forces normal to the tapered surface as low as possible for a given roof and that the more vertical the normal the less overall force is needed at the skewbacks. Hence, the brick of the invention yields not only a llatter curved arch, but also reduces the necessary force imparted to the roof by the skewbacks, since it wil be seen that the normal force is more nearly vertical than in the prior art arches.

The present invention, to accomplish the results indicated above, uses a shape which results in an interlock of the bricks. This interlock incidentally keeps any spalled sections of the brick in place to continue to .perform the functionof a working refractory lining. In the prior art, compensations in roof thicknesses had to be made to allow for these spalled sections dropping out so that the roof thickness had to be made thicker than necessary for an integral roof. In the present invention, the retention of these spalled sections in the roof by interlocking allows the roof to remain smaller in thickness so that a saving in material results. This savings in material reduces to a considerable extent the forces to which the superstructure of the furnace or kiln is subjected.

Considering the invention now in detail, FIGURE l shows an arch in an end elevation constructed according to the prior art. Taper bricks 21 are placed in abutting relationship to one another. The bricks have a taper angle 22 and the arch has a radius of curvature 23 from a center of rotation 24. A normal force 25 must be exerted on the ends of the arch normal to the face 27 to achieve a vertical component 28 of the magnitude of one-half of the weight of the arch 20.

In FIGURE 2 is shown the prior art wherein an arch 30 with the same span as the arch. 20 has an increased taper angle 32 and a decreased `radius of curvature 33. This results in normal force 35 exerted by the skewbacks or other supports being exerted in a direction more closely approaching the vertical than that of normal 25 of FIGURE 1 so that normal 35 can be reduced while still yielding a vertical component 38 of such necessary magnitude to overcome the weight of the arch 30. Thus it will be seen that by increasing the taper angle and decreasing the radius of curvature of a prior art arch structure, less force at the skewbacks was necessarily exerted.

However, the decrease in the radius of curvature of the arch resulted in a heavier roof, since more refractory material was needed to traverse the longer path. This can be seen clearly in FIGURES l and 2 Where in each instance the span is the same. Thus, the roof became heavier as a shorter radius of curvature was used.

A further result of the decrease in radius of curvature was that the arch increased the furnace interior at the center of the arch while keeping the height fixed at the end of the arch, and in many instances, this was undesirable. The result was a bulky furnace structure.

Thus, in the prior art as seen in FIGURES 1 and 2, to increase the taper angle of the brick which was desirable, it was necessary to decrease the radius of curvature of the arch which in most instances was undesirable.

The present invention permits the increase of the angle of taper of the brick without decreasing the radius of curvature of the arch.

FIGURES 3 and 4 show a taper brick 40 of the prior art having an outer circumferential face 42 and an inner curcumferential face 43 which are parallel to one another, and end faces 44 and 44 which are parallel to one another. Radial converging faces 45 and 46 are longitudinally disposed directly opposite one another. The brick has a taper angle 49.

Referring to the FIGURES 5 and 6, it will be seen that a brick has a longitudinal portion 51 and a longitudinal portion 51. The brick has an outer circumferential face 52 and an inner face circumferential 53 which lie in parallel planes. End faces 54 and 54 are parallel to one another and lie in planes perpendicular to the faces 52 and 53.

In the longitudinal portion 51, the radial face 56 desirably forms a 90 degree angle with face 53 and radial face forms an obtuse angle with face 53. Where, for instance, the circtunferential width of the face 52 of the brick of the invention is equal to the width of the circumferential face 4210i the prior art brick 40 and the width of the inner circumferential face 53 at the longitudinal portion 51 would be equal to the width of the face 43 of the prior art brick 40, and the height of the brick 40 is equal to the height of the brick 50, then the angle 58 would be equal to the taper angle 49 of the prior art brick 40.

Considering the longitudinally displaced portion of the brick 50 at 51', the radial face 56 is suitably disposed at an angle of 90 degrees to the face 53 and the circumferential face 55 is disposed at an obtuse angle to the face 53. The radius of curvature for this portion 51 of the brick 50 would be a function -of the width of face 52, the width =of face 53 at the longitudinal portion at 51' and the height.`

The longitudinal portion 51 would have a taper angle 58'.. These would be equal to the corresponding radius of cur-- vature and taper angle of the longitudinally displaced portion 51 of brick 50 as well as the taper brick 40 of the prior art. The brick 50 has transverse faces 57 between portions 51 and 51'.

In the brick 50 of the invention as described above, the radial faces 55, 55', 56 and 56' all lie in different planes. The pair of diagonally opposed radial faces 55 and 55' lie in planes which. form a given taper :angle 59 and the pair of diagonally opposed radial faces 56 and 56 lie in planes which are parallel.

Bricks 60 are placed in an abutting relationship in the formation of an arch 60' as shown in FIGURE 9. The bricks 60 are similar to the bricks 50 described above, except the longitudinally offset

portions

61 and 61 are at the outer circumference of the arch, rather than at the inner circumference as would be the case with the diagonally opposed radial brick 50. The faces 65 and 65 are radial converging faces, while the diagonally opposed faces 66 and 66 are parallel faces. The faces 65 and 65 form a taper angle which corresponds to the angle 59 of the brick of the invention 50. The longitudinal portions 61 and 61' are of substantially equal length so the bricks 60 can suitably interengage one another. It will be seen that the radius of curvature lof this arch would be the same as a prior art taper brick having a taper angle equal to angle 58 or angle 58' in the bricks 50. However, in the brick of the invention and in the arch of the invention the taper angle of the brick is substantially greater than the angle 49, or the angle 58 or the angle 58'. This is because the effective surfaces for transmitting the forces from brick to brick are the

faces

65 and 65 and the faces form a taper angle which corresponds to angle 59 for the brick 50. These faces 65 and 65 become the taper or wedge faces for the brick 60.

In the brick 60 of the invention as described above, the radial faces 65, 65', 66 .and 66 all lie in different planes. The pair of diagonally opposed radial faces 65 and 65' lie in planes which form a given taper angle and the pair of diagonally opposed radial faces 66 and 66' lie in planes which intersect to form an angle different from the given taper angle.

Thus, the brick 50 of the invention as shown in the ernbodiment of FIGURES 5 and 6 as well as the brick 60 of FIGURE 9 has a much greater taper angle 59 than the taper angle 49 of the prior art brick of FIGURE 3 while at the same time maintaining the same radius of curvature as the brick of FIGURE 3 when employed in an arch.

In FIGURE 7, there is shown a further embodiment of the invention. Brick 70 has displaced

longitudinal portions

71 and 71. Circumferential face 72 -and circumferential inner face 73 are parallel to one another and end face 74 and its opposite face are parallel to one another and perpendicular to faces 72 and 73. Radial faces 75 and 76 intersect faces 72 and 73 in longitudinal portion 71 and radial faces 7 6 and 75 intersect faces 72 and 73 in the longitudinal portions 71'. Transverse 'faces 77 join the radial faces 75, 75', 76 and 76'. The faces 75 and 76 form a taper angle of 78, and the faces 75' and 76' form a taper `angle of 78'. The faces 75 and 75 lie in planes which form a taper angle of 79 for the brick. The radial faces 76 and 76 lie in planes which converge at an angle other than that of angle 79.

The embodiment of FIGURE 7 is similar to that of FIGURE 5 except the angle formed by faces 76 and 73 is an acute angle rather than a right angle.

In FIGURE 8, there is shown a rectangular block having the brick of FIGURE 5 imposed thereon in dotted lines. The dotted portions 111 and 112 are removed to form the brick of the invention in the embodiment 50. The basic rectangular shape could be of any relative dimensions with respect to width, height, or length.

In FIGURE there is shown a key section for an arch which is formed from below, where assembly from above is undesirable or impossible. In this embodiment, all the bricks 50 can be inserted in place from below until the final two bricks. Here a split brick having sections 80 and 802 are used. The section 80 is first placed in position against a brick 50 as shown from below. A full brick of the invention 89 in all respects similar to a brick 50 is then placed into position by a lateral movement to the arch in a horizontal direction. The split brick 802 is then placed into position against brick 80', 89 and 50 by a horizontal or lateral movement to key the brick into position.

A further embodiment of the invention is shown in FIGURE 14 wherein external Ioxidizable steel plates 100 are embedded in

faces

53 and 53 of taper brick 50.

Suitable chamfers

101 and 101 are cut into the brick. Tongues 102 lanced from plates 100' are comolded into the -brick refractory. These oxidizable metallic plates reduce spalling and increase the useful life of the brick. It will be evident that where oxidizable metallic plates are used, the refractory material should be of a basic refractory compatible with the plates.

The brick of the invention as used in at arches or spans is shown in FIGURES l1, 112 and 13. In this instance, brick 90 has longitudinallly displaced portions 91 and 91. Radial faces 95 and 96 are parallel and no convergence exists between them, as are radial faces 95 and 96. The faces 92 and 93 are also parallel. There is no angle of taper in longitudinal portion 91 or longitudinal portion 91'. The brick is similar in other respects to that of FIGURES 5 and 7. However, the faces 96 and 96 which become the faces on which a brick is supported, lie in planes which do converge and these faces form an angle of taper 99 which permits the erection of a at arch with an infinite radius of curvature. In FIG- URE 13 it will be seen that in arch 100 forces F1 and F2 at the skewbacks exert a force normal to the downwardly directed faces of the end bricks of the arch 100. The force F1 is transmitted to the opposite face of the same longitudinal portion, diminished by the Weight of the end brick and a force F3 is exerted against the next inwardly placed brick. Thus, flat arches of considerable span can be erected.

While applicant has referred to the `arch and brick of the invention as being self-supporting, the invention is equally applicable to partially self-supported arches or fully supported arches having hanger and other attachment means. Furthermore, the bricks of the invention may be used in walls, floors, and other linings of metallurgical furnaces and the like where suitable. For instance, bricks of the invention can be used where a working refractory lining is used or necessary.

It will be evident that in the brick of the invention first diagonally opposed lateral faces 55 and 55 converge more abruptly on a center of curvature which is nearer to the arch than the arch center of curvature, while the other diagonal lateral faces 56 and 56 are parallel or divergng as best seen in FIGURES 5 and 7.

In View of my invention and disclosure, Variations and modifications to meet individual whim or particular need will doubtless become evident to others skilled in the art, to obtain all or part of the benefits of my invention without copying the structure shown, and I, therefore, claim all such insofar as they fall within the reasonable spirit and scope of my claim.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

A curved refractory arch having a first center of curvature and having an inner and outer circumference comprising a plurality of refractory bricks, each of said bricks having a first longitudinal portion including an end face, a irst inner circumferential face, a first outer circumferential face, and an opposed pair of rst radial faces extending between said rst inner and outer circumferential faces, and a second longitudinal portion including a second end face, a second inner circumferential face, a second outer circumferential face, and an opposed pair of second radial faces extending between said second inner and outer circumferential faces, each of said first and second radial faces lying in separate planes, one of said first radial faces extending in a plane convergently disposed to the plane of a diagonally opposed said second radial face to form a first taper angle supporting said brick in said arch, said planes directed toward and converging at a second center of curvature closer to the arch than the first center of curvature, and the other of said rst radial faces extending in a plane disposed to the plane of the other diagonally opposed said second radial face at an angle different from the said first taper angle and being disposed to the other diagonally opposed said second radial face in a parallel to diverging relationship toward the center of the arch.

References Cited bythe Examiner UNITED STATES PATENTS 1,683 7/ 1840 Delisle 94-13 468,840 2/1892 Steiger 52-575 X 1,281,976 10/1918 Keim 52-575 1,420,810 6/192I2 Bean 52--594 1,530,196 3/1925 Norris 52--286 2,192,642 3/1940 Griffith 52-270 2,3 19,064 5/ 1943 Karmanocky 110-99 2,400,827 5/ 1946 Jones 52-585 2,915,893 12/ 1959 Wilkins 52--309 X 3,005,423 10/ 1961 Longenecker 52-89 X FOREIGN PATENTS 8,392 5/ 1905 Great Britain. 89,961 12/ 1896 Germany.

FRANK L. ABBOTT, Primary Examiner.

JACOB L. NACKENOFF, HENRY C. SUTHERLAND,

Examiner.