US2837044A - Soaking pit cover - Google Patents

Description

June 3, 1958 1.. s. LONGENECKER 2,837,044

SOAKING PIT COVER Filed July 15, 1954 4 Sheets-Sheet l A; q A

INVENTOR. Levi S. Longenec/rer HIS A TTOR/VEYS June 3, 1958 s. LONGENECKER 2,837,044

SOAKING PIT COVER Filed July 15. 1954 4 Sheets-Sheet 2 INVENTOR. Levi S. Lqngenecker WW, flficwiw Hi5 ATTORNEYS o llllllrll mmfnvmv lab W m m ."l m FIIL "J 1 m 0 I I! f 2 I I l Inn a .Wfiw I W v 1 xi! vh 8 r V 3 mm June 3, 1958 L. S. LONGENECKER SOAKING PIT COVER 4 Sheets-Sheet 3 Filed July 15, 1954 R m 1 N G E H V. mnm m c Sam 1 w M v V. B

HIS ATTORNE rs June 1958 1.. s. LONGENECKER 2,837,044

SOAKING PIT COVER Filed July 15. 1954 4 Sheets-Sheet 4 A; Q23 INVENTOR. fi 1 L Levi $."Longenecker F i g. H/s ATTORNEYS wwzlemdw 2,837,M4 Patented June 3, 1958 SOAKWG PIT COVER Levi S. Longenecker, Mount Lebanon, Pa.

Application July 15, 1954, SerialNo. 443,587

6 Claims. (Cl. 110--173) This invention relates to soaking pit covers of a type having a cover frame within which refractories are mounted and to which a sand seal skirt is appended. My present invention may be applied to covers for either an individual carrier or truck mounting or for a so-called suspension mounting and utilization with a pick-up crane.

My present improved construction has been devised to meet a problem of long standing in the field of the construction and utilization of pit covers. Heretofore, those skilled in the art have had the choice of one of two general constructions. porting interlocking refractories and which is provided with downwardly-depending integral side slab .portions to both provide side framing and a sand-seal With the soaking pit. The other type of construction and, the one which is in general use at the present time, is provided with a series of separately bolted-on sand-seal ring pieces which depend from the cover frame about its periphery and define a series of unconnected joints. See my Patent No. 2,178,668.

The integral slab type is essentially impractical for present day utilizations, since the lower reaches of the integral slabs are the portions which are subjected to the greatest heat which may approximate 2650 P. on the pit side of the divisional wall for the soaking pit and about 2200 F. from the inside of the sand-seal. construction thus inherently does not take into consideration the fact that the lower or sand-seal portions, being more directly subjected to higher temperatures, to vertical temperature gradients, and to greater variations of temperature, have a relatively short period of operative life. Thus, an integral slab construction, such as here involved, constitutes a highly expensive utilization from the standpoint that the whole cover has to be frequently replaced. That is, the life of the depending sand-seal portions of the pit cover governs the life of the over-all cover. In addition, an overall construction of this type has a relatively high initial cost.

As to the second type of construction, those skilled in the art have heretofore firmly believed that the only practical and effective way of utilizing a separate sandseal structure is to employ a plurality of edgewise-aligned, but not directly connected, sand-seal plate members which, in effect, provide a series of separate expansion and contraction units depending from the side framing members of the cover frame. In this construction, the purpose has been to make possible, as distinguished from the firstmentioned construction, the separate replacement of the relatively short-life, sand-seal portions, while still making use of the full effective life of the cover frame. Since it is recognized that the refractories when heated up to their working temperatures will expand outwardly, it has heretofore been a criterion that such expansion and the incident contraction which occurs when the cover is cooled, requires a plurality of sand-seal pieces that have free joints therebetween about the cover and ones which are, in effect, separately, or as separate units, secured to The first involves a cover frame for sup- This type of depend from the cover frame. In other words, it has heretofore been thought necessary, when separatelyforrned sand-seal portions are provided, to separately mount or secure them to depend from the cover frame in such a manner that each member or piece will be free to independently contract inwardly and expand outwardly on such frame during the temperature variations to which the cover is subjected in pit usage.

Those skilled in the art, in further carrying out the prevalent conception, as applied to the second type of construction, have gone a step further and provided a pair of bolted-together sand-seal parts or members that are positioned in a vertically-aligned relationship with each other; and which, in effect, form the individual units which are positioned about the frame of the cover. I have determined that the latter type of construction, although having a good purpose, is not practical since the two parts of each unit require substantially horizontal flanges and require vertically-positioned bolts for securing the portions together at such flanges. The high heat and the heat gradients to which such two-part units are subjected, causes them to warp about such flanges and to stress the bolts in tension and shear, causing binding and breakage. Thus, the purpose of providing more flexibility in replacement as to high temperature parts is lost, since warpage necessitates the replacement of the whole unit.

In addition, damage is often done to the side frame structure in attempting to remove the two-part units,'due to the warpage and distortion of the bolts. This construction has the further disadvantage that it does not take into consideration and violates limits of clearance spacing which are encountered in the utilization of a sand-seal ring of a cover.

In both the single-part and two-part separate types of units, the units tend to progressively warp inwardly and this warping is exaggerated when an inward cone is thus formed, due to the weight of the cover on the units when they are in a sand-sealing position and while the cover is being subjected to the heat of a soaking pit. In this connection, pit covers, as utilized, are raised and lowered and positioned over the soaking pit and are then moved to and from the mouth of the soaking pit. The carrier or suspension means does not support the full weight of the cover when it is in position over the soaking pit, as part of the weight of the cover is taken up by the knife edges bearing on the sand to provide an effective seal.

Another disadvantageous factor in the utilization of separate sand-seal units, either of the single or two-part construction above described, is that they are not essentially gas-tight or leak-proof in utilization. As to the single part construction, leakage occurs between the end joints of the units; as to the two-part type, leakage also occurs between the many edge joints, end joints, and between the joints of the two parts of each unit, as accentuated by the temperature variations that are encountered.

In view of the limiting disadvantageous features of the prior art constructions and the problem which has been presented, I set out to analyze and determine what features were essential and what were not and then to devise a solution to the problem.

It has thus been an object of my invention to provide a u tory block assembly of a pit cover, will fully band such assembly, and will apply a controlled compression loading thereto when the pit cover is heated up;

A still further object has been to provide an improved soaking pit cover which is readily adaptable to conventional carriage and suspension agencies and which embodies new principles of construction and utilization;

These and other objects of my invention will appear to those skilled in the art from the drawings and the specifications.

In the drawings,

Figure 1 is a top and side isometric view showing a complete pit cover constructed in accordance with my invention;

Figure 2 is an enlarged side section taken along the line lI-II of Figure 1 and additionally illustrating adjacent sand seal walls:

Fig. 2A is a fragmentary, sectional detail of Fig. 2 illustrating mutual support of the blocks comprising the refractory arch blocks assembly;

Figure 3 is a transverse or end section of the scale of Figure 2 and taken along the line ]IIIII of Figure 1; this figure shows an outer pit side wall and illustrates a division wall between pits and additionally, the side-by-side relationship of pit covers with respect to each other;

Figure 4 is an outer end view of the scale of Figure 3 and taken along the line IV-IV of Figure 1; this view also illustrates a tongue and groove mounting on an outer side of the cover construction and a slide mounting on an inner side which lies adjacent to another pit cover;

Figure 5 is a top perspective view on the scale of Figure 1, showing an integral sand-seal frame or overlapping skirt construction of my invention which in Figure 1 is illustrated as applied to the pit cover for providing a complete assembly;

Figure 6 is an enlarged corner perspective on the scale of Figures 2 to 4, inclusive, and showing details of the construction of corner members utilized in the frame of Figure 5 and of a type for use where the pit cover has end posts; in this connection, it will be noted that end posts are customarily used when the pit cover is to be moved'or controlled by a crane, for example;

Figure 7 is a fragmentary horizontal section taken through a corner of the cover of Figure l and on an enlarged scale with respect to both Figure l and Figure 6; this view illustrates the corner construction of a cover employing end posts;

Figure 6A is a view similar to and on the same scale as Figure 6 and showing the construction of a modified corner member for use with a pit cover having no end posts and thus, of a type suitable for overhead truck control of its movement;

Figure 7A is a horizontal section on the scale of Figure 7 and similar to Figure 7, but showing a modified corner construction utilizing the type of corner member of Figure 6A;

Figure 8 is a fiagmental perspective section in elevation taken along the line VIII-VIII of Figure 1 and on an enlarged scale corresponding to Figures 7 and 7A;

Figure 9 is a fragmental end section inelevation on an enlarged scale as to Figure 8 and taken along the line IXIX of Figure 1;

Figure 10 is a side fragment in elevation taken along the line XX of Figure 1 and on the scale of Figure 8;

Figure 11 is a horizontal sectional fragment on the enlarged scale of Figure 7 and 7A and taken along the line XIXI of Figure 5.

Although in Figure 1 of the drawings, I have, for the purpose of illustration, disclosed a soaking pit cover of a type having corner posts for crane mounting it will be apparent to those skilled in the art that such a construction may be modified in accordance with the showing of Figures 6A and 7A, with corner posts omitted, for the purpose of utilizing a truck mounting for the cover.

Having fully analyzed the prior art constructions and utilizations of pit covers and their disadvantageous features, I set out to devise a new and improved structure which would have the original cost and maintenance economy of the simplest second type of construction and would improve on the better gas-tightness characteristic of the first-mentioned type. After considerable study and experimentation, I discovered that heretofore considered inviolate requirements as to the construction of the second type were fallacious and that contrary to prior beliefs, it was highly advantageous to provide a separately-constituted sand-seal ring which, in effect, would serve as an integral band or peripherally-bounding skirt or frame unit depending from the framing of the cover.

I further discovered that the limiting and detrimental features of both prior art types of constructions could be fully met by providing a bounding, depending sand-seal frame or skirt mounted about the cover frame and made up of individual sections welded together into an integral whole, so constructed and positioned as to become a tension banding member under expansion of the refractories when they are heated up and, to additionally function as a compression binder upon the heated-up refractories.

Contrary to ideas heretofore held by those skilled in the art, this type of construction minimizes damage to the cover frame under operating conditions, in that it permits limited outward expansion, but without breakage or distortion-set incident to excessive expansion, and' serves as a reinforcing band for the cover frame to actually increase its operative life.

ture has a longer life than a construction wherein the'sand' seal is provided by separate, unconnected pieces or units. Also, although it fully bands the refractory block assembly, contrary to engineering thought, it does not cause damage to the assembly, or, itself, tear or break. Additionally, it is more effective in protecting the cover frame and the pit cover structure as a whole. Analyzed, it appears that the forces generated, whether of an outward expansion or of an inward contraction type, are substantially uniformly distributed about and along the unitary skirt, so that no single portion thereof is subjected to a highly localized distortion-setting or breakage force.

Further, employing a construction of my invention, the warpage which is inherent in a construction of the second-mentioned type is no longer present, and the problem of leakage between the joints or seams no longer arises; the sand seal frame is fully gas-tight in its construction and its mounting and has and retains a fully gas-tight relationship with and along the outer reaches of the refractory block assembly carried by the pit cover. More specifically, in my construction, I employ a unitary or band-like skirt that extends upwardly along the lower reaches of the cover frame and about the perimeter of its outside portions to serve as a bounding band about the beam members of the frame and at the lower reaches thereof, and essentially, extends along the upper and lower reaches of the refractory block assembly and in a retaining, banding and bounding gastight relationship fully along and about the block assembly. Such gas-tight relationship is retained when the block assembly tightens up on the skirt with the application of heat and when the heat is removed. It will be noted that lower reaches of the side and end framing members or beams 15 and 15' are protected or insulated from the soaking pit heat by the outer reaches of the refractory block structure or assembly. Additionally, it depends downwardly therefrom to provide an integral, substantially vertically-contained, sand-seal flange or ring. This band-like skirt unit is fabricated from a series of end-to-end positioned side, end or transverse, and corner members, all of which are secured and sealed together at their abutting or adjacent edges by In addition and to my own surprise, it was determined that such a skirt or band, when subjected to variations and extremes of tempera welds. Such a unitary skirt is formed separately from the cover framing. It may be formed on the cover framing or apart from it and then mounted in position over and about its bottom reaches by horizontally projecting bolts. It may be readily removed therefrom for replacement purposes. it serves as a relatively longlife expendable unit which may be repaired or replaced from time to time, while still making use of the original cover framing and refractory block construction.

My practice is to use tight joints between all the refractories or to eliminate all expansion joints in the block assembly, so that a good gas seal will be provided I and maintained. This inherently causes the refractories upon expansion to tighten up upon or between the sand seal skirt when employed in my construction. The thermal expansion is not too great, by way of example, one brick may expand about 3% of an inch per foot, or a group of connected bricks may expand about 1% inches in 20 feet. Nevertheless, the expansion is efiective and particularly so, where, as desired, expansion joints are eliminated between the refractory brick to prevent gas loss, breaking out of the brick and, in general, to provide a gas-tight unit.

In accordance with my invention, the distortion due to thermal expansion and contraction is however limited and controlled and is not haphazard and non-controlled, as inherent in the so-called separate-piece or second type of prior art construction. Also, a tend ency to cause an outward curl or coming of the sand seal or side skirt which is due to temperature gradients along the vertical height of the sand seal construction, is offset by the unitary or continuous-rectangular band type of construction of my sand seal ring and its ten sion mounting on the framing beam members of the pit cover. The continuous length and depth of my sand seal frame or skirt helps it to better withstand temperature gradients without objectional distortion. In my construction, I eliminate a plurality of misbehaving, separately-acting, sand-seal pieces and provide an arrangement wherein the forces generated by thermal expansion and contraction are substantially equalized along the full area and perimeter of the sand-seal frame, as a whole.

Referring particularly to Figure 1 of the drawings, I have shown a pit cover designated as a whole as 10. This cover has longitudinally spaced-apart and transv'ersely-extend-ing arch beams 11 of l-beam construction, longitudinally-extending and transversely-spacedapart cross-channels or braces 12, and bounding framing beam members and 15' of I-beam construction. It will be noted that side framing members 15 interfit with end framing members 15 and are secured together in the form of a substantially rectangular frame by conventional means such as rivets or weld metal. Diagonal brace members 13 are secured to extend at their ends from outer arch beams 11 and to rest upon the arch beams and form bracing therefor; a center plate 14 is also shown; these members are secured in position by weld metal or rivets in a conventional manner. The described construction provides a unitary cover 10 which, as employed in accordance with my invention, has a relatively long period of useful life and is separately constituted from a unitary banding, side skirt or sand seal frame construction which is constructed and mounted to project downwardly from the cover and about the reaches of its framing members.

Referring particularly to Figures 1, 4 and 10 of the drawings, I have shown the side beam members 15 of the cover as extending beyond the transverse or end members 15 to receive end post mounts 16 and 16'. In this connection, the posts 16 are adapted to lie along an outer side of an outer cover, have so-called tongue and groove or ball and socket positioning joints 17, and are mounted on side rails 18, see Figure 4, by means of such joints. The end posts 16 or adjacently positioned covers are of similar construction, but have slide joints 17a which mount them on side rails 18. This latter construction is employed between adjacent covers, such as shown in Figure 3, where, as customary, a series of covers are positioned in adjacent sand seals that surround adjacent soaking pits.

Referring particularly to Figure 5 of the drawings, I have illustrated my novel form of unitary, banding, side skirt or sand seal frame construction 20. As shown in this figure and in other figures, such as Figure 11, this construction is made up of a pair of opposed unitary side skirt or sand sealing framing members and a pair of opposed unitary transverse or end skirt or sand seal framing members, laid out to define a substantially rectangular frame shape and with end portions of each side member in a spaced-apart and adja cent relationship with end portions of the pair of end members. Each of the side and end skirt members is made up of longitudinally-extending, strip-like, end-toend positioned and joined flat metal pieces or portions 21 of relatively heavy section, as noted particularly by comparing the lesser section thicknesses of the framing beam members 15 and 15' of the cover with the pieces 21, in Figures 7, 7A and 11. As disclosed par ticularly in Figure ll, end joints of the sand seal framingmembers (made up of pieces 21) are secured and sealed-off in such a relationship by weld metal w. The sand seal frame members are thus secured in groups to provide opposed side members and opposed trans verse or end framing members and are laid out in a substantially rectangular relationship in which their end corners are in a spaced relationship.

It will be noted that side reinforcing or splice plate members 22 are positioned over the joints between endwise abutting pieces 21 and are welded in position by weld metal w, see particularly Figure 11. The splice plates 22 serve to seal the joints effectively against the intense heat of the soaking pits and to, in effect, laterally reinforce and brace the framing members and their unitary construction, so that they are actually of greater strength at their joints than along their lengths.

When the unitary, endwise-welded-together framing or skirt members are thus provided and laid out in the general arrangement of Figure 5, then angle-shaped corner members or castings 25 are inserted in position at the four corners. To permit accurate sizing of the skirt frame, I utilizespacer bars 27 between ends of the corner members 25 and end pieces 21 of the framing members; weld metal w is utilized to seal-off and secure the spacer bars 27, as shown particularly in Figure 7.

Filler or spacer strip, plate or piece lengths 23 are positioned along the inner sides of the assembled pieces 21 to extend therealong, along corresponding inner sides of the corner members 25 or 25 and, in general, between the outer sides of the webs of the cover framing beam members 15 and 15 and inner sides of the unitary sand seal frame. It will be noted that the strips 23, as shown, extend depthwise downwardly (see Figures 2 and 3) from the top of the assembled pieces 21 and corner members 25 or 25 to shortened flange or stub portions a of the bottom flanges of the beam members 15 and 15. Bolt and nut assembly pairs 26 are positioned at spaced loca tions along the rectangular structure and, extend through the framing beam members 15 and 15, the strips 23 and the members 21 and 25 or 25' of the unitary sand seal frame, to removably secure the sand seal frame 20 and its filler strips 23 to the main cover frame 10.

It will be noted that the spacer or filler strips 23 are constructed separately from the sand seal skirt 20 and are inserted in position between it and the frame members 15 and 15' of the cover construction 10. However, if desired, the strips 23 may be tack-welded to the members 15 and 15'.

Referring to Figure 6, the corner members 25 have a thickened bottom rim or sand seal portion 25a, a vertically-extending and angle-shaped body portion 25b, and vertically-extending and spaced-apart reinforcing ribs 25c extending on an outer side of such body portion. The body portion is also cut-out or slotted at 25d to bypass one of the projecting end portions of one of the side framing members 15 of the cover, itself. This slotting of the corner members 25 is only necessary when end posts, such as shown in Figure 1, are used. As shown particularly in Figure of the drawings, I have also provided the corner members 25 with vertically spacedapart and substantially horizontally or cross-extending reinforcing ribs 25:: that are located on the opposite or inner sides thereof.

As illustrated particularly in Figures 2, 3, 5, 7 and 11, the framing'beam members 15 and 15 of the cover 10 have their bottom flanges sheared-off or cut-away at their outer horizontal extremities to leave the shortened or stub portion a against which the members of the sand seal frame 20 are adapted to rest and abut. Although the outer portion ofthe bottom flange may be completely sheared off, this arrangement is advantageous from a number of standpoints. In the first place, the shearing operation is made easier, since it is not flush with the web of the framing members and 15'. In the second place, it, in effect, spaces the sand seal frame from the cover frame 10 and slows down heat transfer from the hotter sand seal frame 20. In the third place, it makes possible the utilization'of the spacer strips 23 to correspond to variations in the spacing and provide an effective gastight sealand to, in effect,"provide an expansion joint between the cover frame 10 andthe sand seal frame 20. It will be noted that the frame'structure of the cover 10 provides a support for the refractories, while the sand seal skirt 20 binds the outer reaches of their assembly.

As shown particularly in Figures 2 and 3, the bottom edges of the portions 21 of the framing members and of the corner members 25 or 25' of the sand seal frame serve as knife edges to enter a sand trough 36 and seal off a soaking pit, as defined, for example, by intermediate side positioned walls 37 between pits and by outer walls 35. In Figure 3, I have illustrated how two adjacent covers 10 and 10' are positioned on a common partition wall between pits and within respective sand trough portions 36a and 36b.

In Figures 6A and 7A, I have shown a slight modification as to the construction of the corner members 25 and their mounting, where end posts are not used and thus, when the side framing members 15 of the cover do not extend outwardly beyond the sand seal or skirt frame 20. It will be noted that the construction of the corner member 25' is the same as that of the member 25 of Figure 6, except that it does not have the slotted-out portion 25d. It will also be noted from Figure 7A that the mounting of this type of construction is the same as the mounting of the type of construction of Figure 7.

As illustrated in Figures 5 and 9, both types of corner members 25 and 25' have a smooth inner side wall which is provided with reinforcing, vertically spaced-apart, shelf or horizontal rib portions 252 which are at right angles or perpendicular to the vertical ribs 250.

In Figures 2, 3 and 8, I have illustrated how refractory brick or block may be mounted in position and carried by the cover 10 of my construction. As shown in Figure 8, short length I-beam sections or pieces are secured as, by welding, to extend transversely along the shortened or remaining portion of the bottom flange of each of the framing members 15 and 15' and slidably receive filler blocks 31. The blocks 31 have I-shaped slots 3101 therein, so that they may be slid on and off of the channel pieces 30. Regular refractory brick or blocks 32 are then mounted in position in a customary manner, see my Patent No. 2,178,668, to abut the filler blocks 31. Figure 2, I have shown a ship-lap joint 33 between a series of blocks of a given row of blocks. It will be noted, however, that all joints are tightly laid together in my present construction for pit cover usage.

From the drawings and the previous description of the construction and mounting of the sand seal frame or skirt 20, it will be apparent that it is gas-tight, is mounted or secured in a gas-tight manner to the cover 10, and is accurately made to fit tightly about the outer perimeter or reaches of the cover 10 and the shortened bottom flanges of its framing beam members 15 and 15', to extend or project or depend downwardly from such framing beam members and beyond the refractory block assembly. I prefer to construct the frame 20 in position on the cover 10, but have also constructed it separately and then slid it upwardly into position, so that its bolt holes are aligned with bolt holes in the cover frame.

The frame 20 serves as a banding or tensioning frame andis subjected to the highest temperatures; it can be easily replaced as a unit by removing the bolt and nut assemblies or by cutting-out a burnt-out portion and rewelding a new portion therein. In any event, it serves not only to equalize expansion and contraction forces, to

insulate the cover frame and protect it, but to also take the wear and tear which is involved in the utilization of the pit cover. This skirt frame 20 is designed and mounted for easy replacement and repair and to protect and minimize warpage of the cover frame, itself.

Since the parts 21 and 25 or 25 of the frame 20 are all secured together to define a continuous band or skirt,

forces exerted upon it are-equalized throughout its extent to minimize distortion and to enable it to substantially retain its original shape, even although it is subjected to the vertical heat gradients. Although it is of relatively heavy thickness, it permits sufiicient expansion and contraction to avoid damage to the refractory brick or block construction of the cover 10 and minimizes damage to such construction. It is, itself, gas-tight or sealed and provides a positive gas-tight seal essentially with the refractory assembly and incidentally, with the framing or beam members, has a minimum distortion, in itself, and definitely minimizes distortion of the framing members.

It will thus appear that in accordance with my invention, I provide a completely enclosed metal binding unit, skirt or frame 20 which overlaps or abuts the metal bounding members of the cover structure and establishes a tension binder against which the refractory block assembly develops a compression load. The refractory block assembly is carried by the cover frame construction by conventional suspension means (not shown), but such as disclosed in my Patent No. 2,178,668, and is provided with a new and improved form of boundary mounting for filler or side and end blocks, as disclosed in Figure 8 of the drawings. The block assembly is tightly or closely laid together and their joints may be cemented to provide an arrangement which is, in effect, without expansion joints as commonly understood in the art.

The refractory block assembly develops a compression loading as bound by the skirt 20 which results from the greater amount of expansionof its blocks or bricks, as compared to the lesser amount of expansion of the skirt when the structure is heated to an elevated temperature. This produces a compression loading in the blocks and a tension loading in the skirt at elevated temperatures and thus, the skirt operates to control expansion of the block assembly with which it is in a tight and gas-sealed as well as a bounding relationship about its outer reaches. The corner members 25 and 25', in effect, establish tension upon the side and end members of the enclosing skirt unit or frame 20. In this connection, it will be noted that such corner members are strongly reinforced and are so secured and mounted as to distribute the tension load throughout the full area of and along the skirt construction. As shown particularly in Figures 2A and 3, each block 32 has a T-shaped upper end slot 32a to receive lower T-shaped end portion 38a of a hanger casting 38 or 39. Inthis conection, pairs of beam hangers 38 depend from a lower flange of arch beams 11 to hold or suspend the two central blocks or tile of each block bundle or assembly (such as A and 3). Auxiliary hanger castings 39 hold the remaining tile or blocks of the bundle and, as shown, interlock with the hangers 38. Hanger Ts 38a may be secured in the tile slots 32a by a cementitious slurry. Adjacent tile or block 32 are shown cut away at their corners to provide a space or a chamber therebetween. This is shown filled up by insulating media consisting of an inner cementitious material 40 around which a plastic cement or grouting 4-1 is positioned.

Each tile or block 32 is also shown configured on one side face or surface to provide a generally triangular projection or tongue portion 32b and on the other side face with a similarly configurated groove or recess portion 32c (see Figures 2A and 3). Thus, as shown in Figure 2A, adjacent tile or block 32 in each bundle or assembly, such as A and B of Figure 2, may be fully interlocked face to face by the tongue and groove construction.

What I claim is:

1. In a soaking pit cover, framing members defining outer peripheral boundaries of said cover, said framing members having inwardly-projecting bottom flanges, re-

fractory filler blocks below said framing members, shortlength beam pieces secured to bottom faces of said bottom flanges and extending at substantially right angles to said flanges to slidably receive said refractory filler blocks, a refractory block assembly carried by said framing members in side-abutment with said filler blocks, a unitary sand seal frame positioned in tight abutment about said framing members and projecting downwardly therefrom in a gas-tight abutting and expansion-controlling relationship with said filler blocks for engagement with a sand bed, and means securing said sand seal frame in position on said framing members.

2. In a soaking pit cover, metal frame members connected together in a substantially rectangular frame, a unitary metal sand seal band of substantially rectangular shape having spaced-apart and opposed side and end members connected together by one-piece angle-shaped corner members, a tightly-laid assembly of refractory blocks extending across within said sand seal band, means securing said band about lower reaches of said frame in a gas-tight sealed relation therewith to project fully about and below side and end members of said assembly of blocks, and means carried by said frame and said sand seal band to suspend said assembly of blocks in an expansion-controlled relation within a bounding area of said sand seal band and independently of a bounding area of said frame.

3. A soaking pit cover as defined in claim 2 wherein said sand seal band comprises, end-to-end positioned and longitudinally-extending strip-like portions sealed together by weld joints, reinforcing splice bars positioned between ends of said corner members and corner ends of said striplike portions and secured thereto by weld joints to define a continuous-integral sand ssal band.

4. A one-piece angle-shaped corner member for securing together end members of a sand seal band which comprises, an angle-shaped casting having a thickened bottom rim portion, horizontally spaced-apart reinforcing ribs on one side of said member and extending upwardly from said rim portion, and vertically spaced-apart reinforcing ribs on the other side of said member and extending horizontally therealong.

5. In a soaking pit cover, metal frame members connected together in a substantially rectangular frame, a unitary metal sand seal band of substantially rectangular shape having spaced-apart and opposed side and end members integrally connected together at their corners, a flat suspended assembly of refractory blocks of substantially rectangular shape extending across within said sand seal band, said band constituting a tension binder against which said assembly of blocks develops a compression load when the cover is heated to an elevated temperature, means securing said band about lower reaches of said frame members in a gas-tight-sealed relation therewith to project downwardly therefrom, and means positioning said assembly of blocks in side and end abutment with said sand seal band and in a transversely-slidable relation with said frame members.

6. In a soaking pit cover, metal frame members connected together in a substantially rectangular frame, a unitary metal sand seal band of substantially rectangular shape having spaced-apart and opposed side and end members integrally connected together at their corners, a flat suspended assembly of refractory blocks of substantially rectangular shape extending across within said sand seal band, said band constituting a tension binder against which said assembly of blocks develops a compression load when the cover is heated to an elevated temperature, means securing said band about lower reaches of said frame members in a gas-tight-sealed relation therewith to project downwardly therefrom, and said assembly of blocks having filler blocks slidably suspended from said frame members for transverse movement with respect thereto.

References Cited in the file of this patent UNITED STATES PATENTS 1,290,091 Cole Jan. 17, 1919 1,925,118 Stresau Sept. 5, 1933 2,052,187 Mawhinney et a1 Aug. 25, 1936 2,178,668 Longenecker Nov. 7, 1939 2,365,697 Grubb Dec. 26, 1944 2,444,736 Hazen July 6, 1948 2,539,421 Higgins Jan. 30, 1951

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