US3857160A

US3857160A - Hot top installation method

Info

Publication number: US3857160A
Application number: US00390081A
Authority: US
Inventors: F Mueller
Original assignee: COLORADO REFRACTORIES CORP
Current assignee: ADIENCE Inc A CORP OF; COLORADO REFRACTORIES CORP
Priority date: 1973-08-20
Filing date: 1973-08-20
Publication date: 1974-12-31
Anticipated expiration: 1991-12-31

Abstract

This invention relates to an improved method of lining the throat of an ingot mould with a so-called ''''two-piece hot top'''' made up of an identical pair of foldable refractory panel subassemblies, the panels of which are joined together with a fabric hinge. More specifically, the method contemplates hanging the panel subassemblies inside of the mould throat from the rim bordering the mouth thereof such that the hinged joints between panels lie in opposite corners of the mould, then spreading the panels apart until the free edges thereof engage the corresponding edges of the companion panel to form a butt joint, thereafter inserting the ends of a pair of spring wire spreaders through the butt joints and on into the mould corners remote from those occupied by the hinged joints, bending the spreaders at points alongside the midsections thereof so as to place the latter sections diagonally opposite one another in position to enter the hinged corners, and finally releasing the spreaders into position such that the midsections thereof bridge the hinged corners while cooperating with those portions bent around the free edges to bias the panels out into face-to-face contacting relation with the mould walls therebehind.

Description

United States Patent [191 Mueller Dec. 31, 1974 HOT TOP INSTALLATION METHOD [75] Inventor: Ferd A. Mueller, Canon City, C010.

[73] Assignee: Colorado Refractories Corporation, Canon City, C010.

[22] Filed: Aug. 20, 1973 [21] Appl. No.: 390,081

[52] US. Cl 29/463, 29/526, 164/6, 249/137, 249/202 [51] Int. Cl B21d 39/02 [58] Field of Search 29/469, 428, 463, 526; 164/6; 249/202, 137

[56] References Cited UNITED STATES PATENTS 3,362,677 1/1968 Folberth 249/202 3,421,731 l/1969 Koch et a1. 249/202 X 3,732,610 5/1973 Perri 29/463 3,734,454 5/ 1973 McCray 249/202 3,746,298 7/1973 Witt 249/202 X 3,762,033 10/1973 McCray 29/526 X 3,802,058 4/1974 Eccleston et a1. 29/428 Primary Examiner-Charlie T. Moon Attorney, Agent, or Firm-Edwards, Spangler, Wymore 8t Klaas 15 7] ABSTRACT This invention relates to an improved method of lining the throat of an ingot mould with a so-called two piece hot top" made up of an identical pair of foldable refractory panel subassemblies, the panels of which are joined together with a fabric hinge. More specifically, the method contemplates hanging the panel subassemblies inside of the mould throat from the rim bordering the mouth thereof such that the hinged joints between panels lie in opposite corners of the mould, then spreading the panels apart until the free edges thereof engage the corresponding edges of the companion panel to form a butt joint, thereafter inserting the endsof a pair of spring wire spreaders through the butt joints and on into the mould corners remote from those occupied by the hinged joints, bending the spreaders at points alongside the midsections thereof so as to place the latter sections diagonally opposite one another in position to enter the hinged corners, and finally releasing the spreaders into position such that the midsections thereof bridge the hinged corners while cooperating with those portions bent around the free edges to bias the panels out into face-to-face contacting relation with the mould walls therebehind.

3 Claims, 3 Drawing Figures PATENTED DEE3 1 I974 lllu 'llil vFig 2 HOT TOP INSTALLATION METHOD Refractory linings for the neck of ingot moulds are widely used in the steel industry to reduce piping caused by the rapid cooling of the molten steel adjacent the mould walls. These temporary insulating panels are commonly known in the industry as hot tops, one type of which along with the method of installing same forms the subject matter of my copending application for Letters Patent of the United States, Ser. No. 170,699, filed Aug. ll, 1971, now US. Pat. No. 3,797,801.

These hot tops come in various shapes, designs and sizes dictated, in part, by the type of ingot mould in which they will be used. For the most part, however, their salient features are determined as a result of attempting to achieve ease and simplicity of installation while, at the same time, carrying out the all important insulating function. For instance, one such design uses four separate wall panels and four individual wedgeshaped corner posts which, when properly assembled produce an excellent insulated lining for the neck of the mould. The one which forms the subject matter of my copending application already identified, on the other hand, combines two of the corner posts with the adjacent panel members on both sides thereof to produce a couple of foldable subassemblies which, together with the remaining corner posts make up a fourpiece rather than an eight-piece hot top which is considerably easier and less time-consuming to install. Still other hot tops merely consist of refractory panels suspended in some fashion inside the neck of the mould adjacent to its walls.

Now, these various hot top designs leave much to be desired in the way of ease and simplicity of installation although all of them function quite well as insulators. Those with the wedge-shaped corner posts have the advantage of a continuous insulation barrier all the way around the neck of the mould which leaves the mouth unobstructed, but they also have the serious disadvantages of being both difficult and slow to install, very fragile and easily broken especially while driving in the corner parts, and hard to fit, particularly those used in big-end-down moulds that have sloping trapezoidal walls.

In contrast to those hot tops that rely on the use of wedge-shaped cornerposts to hold them in place, there remains a whole group of hot tops that are hung in place by some sort of wire hangers. Still others, comprise combinations of the wedge and hanger systems, the particular one forming the subject matter of my copending application being one of these in that wire hangers are used to suspend the foldable subassemblies in place while the corner posts are driven therebetween. One of the most recently developed systems is of this combination type in that it uses wire hangers to suspend the panels in proper position inside the neck of the mould, but replaces the wedge-shaped corner posts with bowed spring-wire spreaders extending across the throat of the mould from approximately the midpoints on opposed panels. In theory at least, the length of these spreaders is such that when the ends are placed at proper points on the opposed panels, the arch therebetween will reach to one of the remaining panels and hold it against the mould wall.

Of those hot tops using some sort of wire hanger system, probably one of the best is that which is shown in my previously identified application because, once the cornerposts are driven in place, they are primarily relied upon to keep the panels in proper position rather than the hangers. Even so, it suffers from many of the same deficiencies as the eight-piece hot top in that it is still somewhat difficult and slow to use although not quite as hard as the latter eight-piece unit.

The common problem shared by the wire-suspended hot tops is that while somewhat faster and easier to use, most of them include some structures that seriously encroach upon the open throat in the neck of the mould beneath the mouth thereof when the molten steel is introduced. if, as is sometimes the case, molten steel contacts these wires and melts them, the entire hot top may collapse and become useless, especially when such a suspension system is relied upon exclusively to hold it in place. Despite its many advantages, the previously alluded to hot top using the bowed spring wire spreaders suffers greatly from this problem because both spreaders have significant sections thereof between the ends and middle portion well out into the throat of the mould neck were the molten steel is quite likely to contact same while it is being poured. If such should occur in a big-end-down mould, one or more of the panels usually swing in toward one another and lose contact with the mould walls thus allowing the steel to flow in therebehind and cool too rapidly which is the very condition the hot top is intended to eliminate. Sometimes the hot top collapses completely and drops down into the molten steel in the main body of the mould. Either way, the end result is most undesirable and should be avoided, if possible, even to the extent of using some of the more complicated systems which are not frought with this problem.

lt has now been found in accordance with the teaching of the instant invention that all of the desirable features of the spreader-type wire suspension system can be realized while eliminating virtually all of its disadvantages by the novel, but unobvious, expedient of running the spreaders from one corner to the opposite corner along the panel surfaces therebetween in a manner to continually bias the latter back solidly against the corresponding mould walls. As the portions of each spreader adjacent the ends thereof emerge from the corner and through the joint or crack defined between the overlapping free edges of the adjacent major and minor refractory panels and return to the inside faces of the latter they have a pronounced tendency to dig in and hold these edges back tight against the mould wall where the entire panel must stay if it is to remain effective as an insulating medium. This same biasing action tends to spread the overlapped panels apart in the diametrically-located corners of the mould. As this happens, the hinged corners are forced into the corners of the mould and the panels themselves are held tightly against the walls of the latter. In addition, those portions of each spreader adjacent the center section thereof that bridges the hinged corner are also pressing hard against the inside faces of the panel alongside the hinge so as to firmly bias same out against the mould walls. Thus, substantial biasing forces are at work on both ends of each panel functioning to hold them snugly in face-to-face relation against their respective mould walls so as to efficiently insulate the latter. Notwithstanding the above, the spreaders remain closely adjacent the hot top panels throughout their length and leave only a minimal portion exposed to the inflowing molten steel out in the throat of the mould neck.

The improved method of the present invention, therefore, contemplates hanging each of the foldable panel subassemblies by the hinge in opposite corners of the ingot mould, swinging the major panels of each subassembly out into face-to-face contacting relation with the corresponding mould wall, spreading the minor panels apart so that their free edges engage and hold the major panels in place, and maintaining the panels thus positioned by bending the spring wire spreaders so as to run in opposite directions from one overlapped corner to the other past the hinge, the portion intermediate the ends of each spreader engaging both panels of each panel subassembly along both free edges thereof and also adjacent the hinged connection therebetween in a manner to bias some solidly against the mould wall therebehind. Thus, by merely running the spreader wires from corner-to-corner rather than from side-toside as has been done in the past, a much improved hot top retaining system results.

Accordingly, it is the principal object of the present invention to provide a novel and much improved method for installing two-piece hot tops.

A second objective of the invention herein disclosed and claimed is the provision of a method of the type aforementioned that is much faster than any of the methods requiring a wedge-shaped corner post to be driven into the space between the free edges of adjacent panels.

Another object of the within described invention is to provide a hot top installation method that results in the spreaders being placed such that they lie closely adjacent the inside faces of the panels while leaving the throat of the ingot mould neck relatively unobstructed to receive the molten steel.

Still another objective is the provision ofa method of the class described that requires no tools or special skills on the part of the personnel responsible for installing the hot tops.

An additional object is to provide a hot top installation method of the type utilizing spring wire spreaders wherein the placement of the spreader ends in opposite corners of the mould insures the fact that the bend therebetween will not only engage, but tightly and uniformly bias the panels of each subassembly solidly against the walls therebehind.

Further objects of the invention are to provide a hot top installation method that is easy, simple, versatile, efficient, reliable and readily adaptable to various types and sizes of ingot moulds.

Other objects will be in part apparent and in part pointed out specifically hereinafter in connection with the description of the drawings that follows, and in which:

FIG. 1 is a fragmentary perspective view looking down into the throat of an ingot mould through the mouth thereof where the hot top, wire hangers and spreaders therefor are shown in place, substantial portions having been broken away and shown in section to more clearly reveal the construction;

FIG. 2 is a top plan view of the completed installation; and,

FIG. 3 is a greatly enlarged fragmentary section showing the construction in the corner where the major and minor panels overlap.

Referring next to the drawings for a detailed description of the present invention and, initially to FIGS. 1 and 2 for this purpose, reference numeral 10 has been chosen to represent in a general way a conventional ingot mould, only the'neck 12 of which has been shown. The inside of the neck will, for present purposes, be referred to as the throat 14 thereof and the upwardly-facing entrance thereto through which the molten steel is poured, the mouth 16. The particular neck illustrated in FIG. 1 is like that found on a socalled big-end-down" ingot mould and the method of the present invention will be described in connection with installing a two-piece hot top that has been broadly referred to by reference numeral 18 in the throat of the latter; however, it is to be clearly understood that this method is, by no means, restricted to such a use and it can, without modification, be practiced as a method of installing appropriatly-designed hot tops in other types and sizes of ingot moulds.

The method is specifically designed for use with what will henceforth be denominated as a two-piece hot top of the type having an identical pair of foldable refractory panel subassemblies 20 hinged intermediate the ends thereof by a fabric sheet 22 permanently fastened to their inside faces 24 in position to bridge the joint therebetween and define hinge 26. Ideally, this fabric sheet is molded integral with the panels themselves and is impregnated with a refractory material capable of withstanding the temperature of the molten steel although, obviously, other types of hinged connections can be used and the method forming the subject matter hereof will work just as well. i

It will also be noted that, in the particular form shown, each of the panel subassemblies 20 has what will be denominated here as a major panel 28 and a minor panel 30, the only difference therebetween being in their respective widths. The major panels 28 are both of a length to reach all the way from one corner of the mould to an adjacent corner thereof, whereas, the minor panels are narrower by an amount approximating the thickness of a single panel. As so constructed, the abutting free edges of the major and minor panels of the two panel subassemblies will occupy an overlapped relation to one another in the corners remote from the hinges as clearly revealed in all three figures. The advantages of such a construction are two-fold, namely, it provides better insulation in the corners and the minor panel constitutes a structure capable of temporarily holding the major panel solidly in place against the mould wall when swung outwardly thereagainst in gate-like fashion. This overlapped condition cannot be relied upon to hold the hot top in place while the ingot is being poured but it is, nevertheless, helpful as a means for doing so until the spreaders 32 can be installed. Here again, while the use ofa two-piece hot top having major and minor panels in each panel subassembly has certain advantages both in terms of ultimate function and ease of installation, the method defined herein is equally well suited for use with two-piece hot tops having equal-width panels in each panel subassembly assuming, of course, that the cross-section of the mould throat is square rather than rectangular.

The hangers 34 by means of which the hot top is suspended within the throat of the ingot mould are revealed most clearly in FIGS. 1 and 2 to which continued reference will be made. They consist of nothing more than inverted generally U-shaped

wires having legs

36 and 38 of different lengths, both of which terminate at their free ends in upturned hooks 40 turned in wardly toward one another.

The first step in the method is to hang the panel subassemblies in opposite corners of the ingot mould. This is accomplished with hangers 34 as follows. Initially, a choice must be made as to whether the hot top is to hang high or low in the throat of the mould and the hanger leg is selected accordingly. Ordinarily, the appropriate hanger leg will be run down along the inside of the hinged joint and hook 40 will be hooked beneath hinge 26 in the manner most clearly shown in FIG. 1 before the hanger itself is hung over the rim 42 of the mould in one of its four corners. Single-hook hangers can, of course, be used in place of the double-hook ones shown as can other types and styles of hangers capable of suspending the hot top subassemblies in the mould throat. The particular hangers shown have the advantage of being well out of the way of the molten steel as it enters the mouth of the mould while remaining simple and versatile due to their reversability.

Now, with the panel subassemblies being in place in opposite corners of the mould, the normal tendency will, of course, be to have the hingedly interconnected panels thereof fold in toward one another, especially in a big-end-down mould where the throat widens from the mouth down and the hangers tilt in toward one another at the top. The next step, then, is to spread the major panels 28 apart until they lie flush against their respective mould walls, whereupon, the minor panels 30 can be swung out in gate-like fashion so that the free edges 44 thereof engage the inside faces of the major panels in overlapping relation so as to temporarily hold the latter in place as shown. In actual practice, the subassemblies are placed in the throat of the mould such that the minor panels of each such subassembly are folded inside the major panels of the other subassembly. Then, by merely swinging the minor panels out, the free edges 44 thereof will slide along the inside faces of the major panels of the other subassembly and push them out against the mould walls. Upon completion of this operation when the free edges of the minor panels reach the corresponding edges of the major panels, all of the free edges will be in the corners of the mould and the minor panels will also lie essentially flush against the mould walls therebehind.

With the panels thus temporarily held in place, the time has come to secure them there by installing the spreaders 32. In accordance with the prior art method, the ends 46 of each spreader would be inserted into the opposite panels as close to the midpoint thereof as possible and then the center section of the wire would be pulled in and released against the central area of one of the panels therebetween. The problem with this method is that if the points are inserted too far from the middle panel, the bend will never reach the latter or, if it does, said panel will be only weakly biased against the mould wall therebehind. Conversely, if the spreader ends are inserted too close to the middle panel, it may not be possible to bend the wire enough to bring the midsection thereof into position where it will pass in front of the latter thus leaving it loose. Furthermore, even when properly installed, the spreaders make essentially three-point contact at the midpoints of the three panels thus leaving the sections intermediate the midpoint and the ends well out in the throat of the mould where the molten steel is most likely to contact same and melt the wire. If this should occur, the bias holding the panels in insulating relation to the mould walls is lost and the molten steel will rise up therebehind and become chilled so that the primary function to be served by the hot top is lost. Not infrequently, the loss of the spreaders will allow one, if not both of the panel subassemblies to come loose from its hanger and fall down into the main body of the ingot being formed as the molten steel contacts its partially folded leaves or panels.

All of the aforementioned difficulties are eliminated in accordance with the teaching of the instant invention wherein the spreaders 32 are installed as shown in FIGS. 1, 2 and 3 to which detailed reference will now be made. Instead of having to locate the midpoints of opposite panels as has been the situation up to now, the free ends of each spreader are merely passed through the joint 48 defined by the overlapping panel edges and into opposite corners 50 of the mould. All guess work is eliminated and, in fact, the spreader ends will automatically seek and seat in these opposite corners if, perchance, one were to miss the joint 48 a little bit. It is not necessary that the spreader ends be located halfway up the joint between panels although, preferably, they should be positioned nearer the middle than either the top or bottom. While the location of the hot top in the low or high position and the placement of the spreaders relative to the top and bottom thereof will have some effect on the tension developed in the wires and the biasing force exerted upon the panels in those moulds having tapered throats, the overall effect will be slight and of no consequence.

Now, in contrast to the prior art method of installing spreaders, each spreader bridges only the two panels of g the same subassembly rather than three. As indicated most clearly by the arrow in FIG. 1, the portions of each spreader 52 alongside the midsection 54 thereof are grasped and bowed inwardly to bring said midsection inside the hinged corner 56, whereupon, it is dropped down to a level essentially coplanar with the ends and released. As this occurs, a point on each of the spreaders immediately adjacent the opposite ends thereof will pivot around the fulcrumforming free edges of the panels of one panel subassembly thus forcing them solidly against the form wall therebehind, while, at the same time causing the ends projecting therebeyond to dig their way into the relatively soft overlapped free edge of the panel terminating in the same joint.

From the corners of the panels, the wires may bow slightly inward away from inside surfaces of the latter only to return at a point adjacent the hinged corner as revealed most clearly in FIG. 2, however, these spreader wires are usually sufficiently stiff to remain quite close to the panel wall therebehind for nearly the full length thereof and, in many instances, force their way into the panel surfaces so as to remain in contact therewith all the way up to near the hinged corner. Once again, the midsection 54 of the wire leaves the panel surfaces to bridge the hinge therebetween with a bow or bend that still leaves it well out of the path of the incoming molten steel. The biasing force exerted upon each panel is essentially uniform and all are biased firmly against the mould walls therebehind so as to maintain a flush insulating relation thereto.

Of course, each of the two spreader wires extends in a direction opposite to the other around the hinged corner of the mould from the shared or common joints 48 between the lapped ends of the two panel subassemblies. In so doing, each spreader wire cooperates with its particular panel subassembly to bias the other panel subassembly tightly into the corner in which its hinge is located. This occurs because the spreader wires employ the free edges of their own panels as fulcrums around which they bend while the ends beyond said bends engage the free edges of the other panel subassembly and urge them toward the hinged corner, all of which is revealed in FIG. 3. This particular cooperative relationship is particularly evident in two-piece hot tops of the type shown having major and minor panels in each panel subassembly although, it may occur to a lesser extent in those hot tops having the panels sized to meet and mate in the corners remote from the hinges in the same way they do at the hinges. Note, also, that as the spreader ends dig into the panel edges and seat in the corners of the mould, they define hot top supporting structures capable of maintaining the position of the latter in the mould throat even without the hangers.

What is claimed is:

l. The method of installing a two-piece hot top of the type consisting of a pair of identical foldable refractory panel subassemblies within the generally rectangular throat in the hollow neck of an ingot mould which comprises the steps of: placing the foldable joints between panels of the respective panel subassemblies in opposite corners of the mould throat, suspending the subassemblies thus positioned from the rim of the neck bordering the mouth into the throat thereof, unfolding the panels of each panel subassembly to the point where the free edges of one engage those of the other to define butt joints therebetween, inserting the ends of a pair of spring wire spreaders through the butt joints thus formed and into those corners of the mould throat remote from the ones occupied by the foldable joints, independently bending those portions of each spreader adjacent its midsection inwardly so as to locate the latter sections diagonally opposite one another in position to enter the foldable joints, and releasing the spreaders into positions such that-the midsections thereof engage the inside panel faces at spaced points on opposite sides of the foldable joint while those portions adjacent the spreader ends pivot around the free edges of their respective panel subassemblies and cooperate with said midsections thereof to bias the panels outward into tight face-to-face contact with the mould walls therebehind.

2. The method as set forth in claim 1 which includes the step of using the free edge of one panel of each panel subassembly to engage and hold the adjacent panel of the other panel subassembly out against the mould wall therebehind while the spreaders are being installed.

3. The method as set forth in claim 1 in which the panel subassemblies are suspended from the rim of the mould neck by backing same over the latter and underneath the hinged joint.

Claims

1. The method of installing a two-piece hOt top of the type consisting of a pair of identical foldable refractory panel subassemblies within the generally rectangular throat in the hollow neck of an ingot mould which comprises the steps of: placing the foldable joints between panels of the respective panel subassemblies in opposite corners of the mould throat, suspending the subassemblies thus positioned from the rim of the neck bordering the mouth into the throat thereof, unfolding the panels of each panel subassembly to the point where the free edges of one engage those of the other to define butt joints therebetween, inserting the ends of a pair of spring wire spreaders through the butt joints thus formed and into those corners of the mould throat remote from the ones occupied by the foldable joints, independently bending those portions of each spreader adjacent its midsection inwardly so as to locate the latter sections diagonally opposite one another in position to enter the foldable joints, and releasing the spreaders into positions such that the midsections thereof engage the inside panel faces at spaced points on opposite sides of the foldable joint while those portions adjacent the spreader ends pivot around the free edges of their respective panel subassemblies and cooperate with said midsections thereof to bias the panels outward into tight face-to-face contact with the mould walls therebehind.