[1]Patented Feb. 22t 19M 211089871 UNITED STATES PATENT OFFICE 2,108,871 OBECKERWORK Henry L. Sm&Uey, Chicago, M., asggner to Harbison-Walker Refractories company, Pittsburgh, Pa., a corporation of Pennsylvania APPHeation May 26, 1937, BerW No. 144,907 9 Claim3. (CL 263-19) This invention relates to regenerative fumacbs and, more particularly, to a regenerative cheekerwork for such furnaces. Many elements enter into,the ability of a regenerative checker-work to function efficiently. For one thing, the weight per cubic foot of the regenerative checker-work should be as high as possible to provide the maximum heat storage capacity for the regenerator. Also, the cheeker10 work should be constructed to produce a maxinium area of heat transfer surface and a large volume of brick per cubic foot of checker chamber. Another, and very iinportant, factor is the abiuty of the regenerative checker-work to dis15 tribute the air and gases passing through it and over its surfaces. This lastmentioned factor, in reality, controls the others for the air must be distributed before full advantage can be taken of the other factors. 20 However, an undesirable feature of many regenerativechecker-works available heretofore is that dust from the furnace gases deposits on the surfaces of the bricks forming the checker-work. This accumulation of dus't not only retards the 25 flow of gases through the regenerative checkerwork but also retards heat exchange between it and the gases passing therethrough. Oftentimes, severe fouling of the checker-work, rather than the condition of the furnace brick-work, brings 30 the furnace campaign to a close. Obviously, It is highly desirable to maintain the surfaces of the checker-work as free as possible from these dust deposits. Heretofore, the removal of the dust deposits has been difflcult, and often It has en35 tailed rebuilding the structure with replacement of damaged brick, or special constructions open to various disadvantages have been necessary. An object of this invention Is to provide a regenerative checker-work which minimizes dust 40 accumwation and which can readily be freed from dustdeposits. Another object of this invention Is to provide a regenerative checker-work which is constructed to distribute gases flowing therethrough over the 4,5 surfa@es thereof for optimum lieat exchange. Another object of this invention is to provide high weight of cbecker brick per cubic foot of regenerative checker-work volume. A further object is to provide a regenerative 50 checker-work which Is easily installed and which, once Installed, Is of a solid, durable construction.' Still another object Is to provide a regenerative checker-work which is constructed largely from bricks of ordinary rectangular forzn, i. e., 55 straights,'and which is easily construipted, The Invention wjll be described with particular reference to the drawings, in which Flg. 1 is a perspective view of a checker-work constructed in accordance with its preferred embodiment; - Plg. 2 a sectional view taken on line II-II of Fig. 5 1; Mg. 3 a sectional view taken on line III-M of Fig. 2; Fig. 4 a perspective view of a straight; Flgs. 5 and 6 perspective views taken from the top and bottom, respectively, of the stretchers used in constructing the checker-work shown in Mgs. 10 1 to 3; Blg. 7 an end elevation of a modifled form of stretcher; Flg. 8 a perspective view of a righthand stretcher; and Plg. 9 a perspective view of a left-hand stretcher. The checker-work shown In the drawings is 15 constructed from brick shapes I (Fig. 4) and 2 (Mgs. 5 ar%d 6). It is constructed largely from ordinary straights i that are disposed on edge in courses 4. The courses 4 comprise a plurality of longitudinary aligned and abutted straights 1 20 forming parallel rows 6 spaced to receive similar ..:straights extending between the rows 6 and aligned In rows 6a normal to the rows 6. In each course rows 6 and 6a thus cooperate to form separate flue openings, as seen in the drawings. 25 The co es 4 are separated by interme a e courses 5 built from aligned and abutted special shapes, or stretchers, 2 (Flgs. 5 and 6) which mount the straights 1. To this end they are provided on one face with a longitudinal groove 7 30 adapted to receive the edge of bricks 1. This is traversed midway of the brick length by a similar but transverse groove 8. The opposite face Is recessed at edch end to provide portions 9, Mg. 5, of such length that when two of the stretchers are 35 abutted there is formed a groove which receives the edge, or side, of straights I with @a slight clearance. The recesses 9 are connected by'a longitudizf@l groove I 0 similar in width to the groove 7. As shown in Figs. 1 to 3, the stretchers 2 form a 40 plurality of rows, or Intermediate courses, 5 which are parallel to and disposed between the rows 6. Preferably the stretchers are mounted, as seen best in Fig. 1, with the grooves 7 pointed downward and thus engaging a lower row. 6, while 45 grooves IO are turned upward to receive the edges of the straights in the overlying row 6. The rows of stretchers thus combine with the rows 6 to form a plurality of walls 12 that extend from the top to the bottom and from end to end of the 50 checker-work so that each adjacent pair of wars forms a separate flue through the checker-work. The transverse grooves 8 and the recesses 9 are allgned transversely of the checker-work 2 and receive th-e edges of the straights forming the 55
[2]2 2,10S,871 row3 la. I;Irom Fig. 1 it will be seen that the straights I forniing the rows $a extend between adjacent pairs of the walls 12 transversely of the flue formed thereby. As the recessed portions 9 are at the ends of the stretchers 2, and the transverse grooves I are at the center of the opposite sides thereof, thestraights which are positioned thereby are staggered, as best shown in Flg. 2. By thus staggering the straights forming the rows 10 la, the gases passing through the flues forned by walls 12 are forced to fouow a tortuous path ,so that they must contact the surfaces of the cross rows $a, thus affording maximum heat exchang-. ing contact. 11 15 The spacing of the cross checkeris is governed, of course, by the length of the stretchers 2, so the flue aize can be varied by the use of stretchers of appropriate length. Tbus, using 9 x 41/2 x 3inch itraights and stretchers of the same di20 mensions, the cross straights will be on 9-inch centers, providing a flue opening six inches mquare. If a larger opening Is needed, the stretchers ean be made longer, say ten Inches, which wo@Wd give an opening 6 x 7 Inches. And 25 the stretchers can be made to take, other sizes of straights, or to vary the distance of the straights, according to need. The stretchers 2 are provided on one side with noses 14 that protrude into the':ftues of the checker work and which produce turbulence In the ffa.ses flowing through the checker-work. In the construction shown, noses 14 project in opposite directions from adJ&Cent courses of the stretchers 2, as seen particularly In Plg. 3. 7be noses 35 may of course be disposed In arrangements other than shown In the drawings. With ordinary 9inch straights the stretchers shown suffice for buading the particular structure shown. With larger sizes of brick, or for other nose disposi40 tions, It may be necewary to use right- and @lefthand stretchers, as those skilled in the art will understand. 7bus In Mg. 8 the nose portion 14b Is to the right of the recessed end portion Ob, whfle In the left-hand stretcher shown In Plg. 9 45 the nose portion 14c Is to left of the end portion Be when looking axiaUY along the stretchers when they have recessed end portions at the top of the closer end thereof. It will be' seen that the stretcher courses are formed by alternately posi50 tioned lefts and rights which are placed with the recessed portions Ob and So abutting whereby ,the noses project In the same direction. By use of these stretchers, standard 911 straights can be uied to complete the construction, if desired. In 55 all events, the rows la may b6 kept on 911 centerseventhoughl3%"stretchersareused. A jurther feature of the left- and right-hand straights is that they may be formed In any suitsWe length whereby the transverse rows Oa may 60 be spaced as desired. Also, nos@s may be provided on both sides of the stretchers, as shown at 14a, lMg. 7. Such a construetion is advantageous because It permits regulation of the size of the vertical flue opening o5 within rather wide limits, using standard straights and no special shapes other than the stretchers. Since the stretcher courses 5, which separate the courses 4, have no transverse members, longitudinal openings are formed which are open from end 70 to end of the chtcker-work between the courses 4. The arrows in Plg. 2 Indicate typical examples of these openings which extend the width and length of the separate:dues of thechecker-wor ' k. To expectte the lancing, and thereby the clean75 ing, of the checker-work, I prefer to provide at least one course la, and preferably, several spaced courses, of the stretcherb 2 that are appreciably thicker than the others. This facilitates the Introduction of steam or air pipes, or other cleanIng apparatus, into the checker-work so that the 5 accumulated dust can be easily and raplcuy removed from the surfaces of the checker-work without structural change thereof. Since the thicknew of the stretchers govems the height of these vertical flue openings, it will be 3een that 10 these :dues can be varied In height, particularly for lancing purposes. Also, courses 5a of 'Such thicker stretchers may be disposed as often as need be to provide enoug4 horizontal :dues for adequate lancing. 7bus, lriatead of being dis- 15 posed as shown, courses k may be altemated with the twnner stretcher courses to provide a isubstantial number, say five to seven, of horizontal lancing flues at the top of the structure. The checker-work con3truction provided by the 20 lnventlon permlta the ready insertion of steam or air pipes therein and is designed to allow the ejected steam to directly impinge on a large areil of the surface thereof, i. e., this being a good method of cleaning checker-works. By provid- 25 Ing a plur&Uty of separate flues In my checkerwork, I not only keep eddy currents to a niinimum, but also faeflitate the cleaning thereof by permitting stearn pressure to be built up in the separate flue& due to the relatively small v6lume 30 thereof. A particular advantage of this construction is that the checker-work Is composed largely of straights. These can be molded with vacuum to provide high density brieb with consequent max- 35 imum capaeity for heat storage. High presstire molding is not appheable to irregwarly shaped bricks so that the potential heat storage of the checker-work provided by this invention is raised by utihzlng a large proportaon of straights 40 In Its construction. 7bese dense bricks also provide a high weight of checker brick per cubic foot of checker volume. Since the majority of the bricka used In this Invention are of ordinary, rectangular shape, e. g., stanctird straights, and 45 the positioning bricks are adapted to reeelve the rectangular bricks, the checker-work is easily constructed, and, once built, of a solid, durable nature. The provision of a large number of standard 50 straights pemits the use of a relatively large vol=e of brick per cubic foot of checker chamber. This, in turn, provides a large area of heat transfer surface per cubic foot of checker chamber. ne staggered :Mue openings through the cheek- 55 er-work 2 function to distribute the gases over the surfaces of the checker-work. 7bis provides ample opportunity for the absorption of heat by the checker brick from the heated gases, or the release of heat to Incoming air. 7nus fuU ad. 00 vantage can be taken of the potential heat storage capacity of the checker-work. At the same time, the transient gases only directly impinge on the bottom (or top) surfaces of the straights forming the rows la. This means that there id 05 only a rainimum opportunity for accumulation of dust Jn the checker-work. Various modi:ftcations are perrnissible. Flor tnsts,nce, walls 6 may be built from 9x4l/2 straights which are 3, 2% or 2 inches thick, or of. other 70 thicknesses. As the thickness Is reduced, the brick are laid on smaller flue centers, thus increasing the number of ffues which increases the area of exposed heat-exchomging surface. Other advantages also accrue from the lnven- 75
[3]2,108,871 3 tion. Among them reference may be made to ease of stacking standard shapes, and high salvage recoveries in rebuilding checkers built Inaccordance with the Invention. . 5 According to the provisions of the patent statutes, I have explained the principle and construction of my invention, and have Illustrated and described what I now consider to be Its best embodiment. I-rowever, I desire to have It un10 derstood tbat, within the scope of the appended claims, the Invention may be practiced otherwise than as specifically Illustrated and described. I
