US3437308A

US3437308A - Combination hot top,liner and bottom ring

Info

Publication number: US3437308A
Application number: US677000A
Authority: US
Inventors: Darold W Thiem; C Wesley Kramlich; Richard B Ballmann
Original assignee: Universal Refractories Corp
Current assignee: Universal Refractories Corp
Priority date: 1967-10-15
Filing date: 1967-10-15
Publication date: 1969-04-08
Anticipated expiration: 1986-04-08

Description

D- W. THIEM ET L COMBINATION HOT TOP, LINER-AND BOTTOM RING Original Filed Jan. 28, 1965 p ils, 1969 NVENTO w WA m m EM R HAA A TRB B y .K e W B E n U m L D SA L OEH AA WC W MGR R Y B April 8, 1969 D. w. THIEM ETAL. 3,437,308

COMBINATION HOT TOP, LINER AND BOTTOM RING Original'Filed Jan. 28, 1965' Sheet 2 ofS so FIG.7.

. RONALD E. BARRY Attorney April 8, 1969 D w TH|EM ET AL 3,437,308

I COMBINATION HOT TOP, LINER AND BOTTOM RING Original Filed Jan. 28, 1965 Sheet of 3 FIG.4 so

' INVENTORS DAROLD w. THIEM awesuav KRAMLICH RICHARD a. BALLMANN BY RONALD E. BARRY AHorney United States Patent US. Cl. 249-201 6 Claims ABSTRACT OF THE DISCLOSURE Disclosed herein is a hot top including a unitary cast metal casing having an open center which tapers outwardly from the top toward the bottom and an inwardly projecting flange around the top, an insert liner unit positioned within said casing in engagement with the flange with a portion of the liner projecting beyond the end of the casing and a bottom ring assembly including a refractory bottom ring secured to the metal casing with a groove in the bottom ring in engagement with the portion of the liner projecting beyond the end of the casing and a wiper strip secured to the bottom ring and having outwardly extending wiper blades one of which rests on a ledge on the outer periphery of the bottom ring.

This application is a continuation of our copending application Ser. No. 428,731, filed J an. 28, 1965 and now abandoned.

This invention relates to hot tops and more particularly to a unique combination of a hot top casing, a disposable liner and a disposable bottom ring assembly.

Hot tops of the reuseable floating type are well known and usually consist of a casing, insulating lining, protection liner and bottom ring. The casing is made from a number of castings which are secured together to form a unitary structure. A reuseable insulating brick is cemented into the casing and a protective lining either coated on the brick or is made in a preformed sheet which is supported 0n the bottom ring. The hot top is designed to reduce the efliects of piping during solidification of the ingot by slowing the rate of heat transfer through the walls of the hot top and also to reduce the amount of scrap which results in cropping the ingot. The major objective in accomplishing these results has been to reduce the volume of molten metal which must be retained in the hot top in order to overcome the effects of piping. Hot tops are being designed with expensive insulating brick covered with equally expensive protective exothermic compounds and/ or special cover devices or insulating compounds. A reduction in the volume of the hot top has been achieved by using these insulating materials and/or exothermic compounds but it has now been found that the efliciency gained in percentage yield in using these insulating materials is lost when considered with respect to the time required to assemble them.

One of the principal objects of the present invention is to provide an improved hot top that can be quickly and easily assembled.

Another object of the present invention is to provide an improved hot top through the combination of a hot top casing, a disposable liner and bottom ring assembly that interlock to form an integral hot top structure.

Another object of the present invention is to provide a hot top with a one-piece casing which is of the reuseable floating type.

Another object of the present invention is to provide an improved hot top which combines a one-piece cast casing with a disposable liner and a disposable bottom ring assembly in a unique manner.

3,437,398 Patented Apr. 8, 1969 Another object of the present invention is to provide an improved hot top which can be readily adjusted in its depth of penetration into an ingot mold.

These objects are accomplished by combining a onepiece cast metal casing having a grooved flange around its upper open end with a number of preformed disposable refractory liners which are placed on the inner surface of said casing and seated in the groove in the flange and a bottom ring assembly having a grooved surface which engages the liners and the casing to form a unitary structure. The hot top casing is cast as a single unit with lugs cast on its outer surfaces. Wedges of selectively interchangeable lengths are placed between the lugs and the top of the ingot mold to vary the depth of penetration of the hot top into the ingot mold. The liner is locked in position by the cooperative action of the groove in the casing and the groove in the refractory ring for the bottom ring assembly. The use of a disposable preformed refractory liner to protect the inner surfaces of a one-piece casing is a new and unique concept in hot topping art. Liners have been used previously but primarily to protect reuseable insulating bricks located on the inside of the casing.

In designing the refractory ring for the bottom ring assembly, a single bladed wiper ring was used to form the seal in the gap between the ingot mold and the hot top. These single bladed wiper rings have been used extensively in this art with considerable success but failures still occur. This has been attributed to the inability of the single wiper blade to provide a suflicient chill in the molten metal to establish the seal particularly where high temperature metals are being poured.

In view of these failures, another object of the present invention is to provide a bottom ring assembly for a hot top which prevents leakage in the gap between the ingot mold and hot top.

A further object of the present invention is to provide a bottom ring assembly for a combination hot top casing and a disposable refractory liner which has a flexible wiper blade on the wiper ring for the bottom ring assem- A still further object of the present invention is to provide a wiper ring for a hot top which will produce a secondary chill in the event the molten metal in the gap between the hot top and ingot mold is not solidified by the initial chill.

These latter objects are accomplished by using a wiper ring for a bottom ring assembly that includes a double wiper blade on the outer peripheral surface of the refractory ring for the bottom ring assembly. The blades are formed by bending the upper portion of the side wall of the refractory ring outward so that it angles upward from the side wall of the refractory ring and then bending the end of the blade back into engagement with a ledge on the outer periphery of the side wall of the refractory ring to form the second blade. The ledge allows a limited amount of movement between the wiper'blades and the refractory ring which is suflicient to compensate for any deflection of the blades which may be caused by bumping the hot top against the side walls of the ingot mold when it is lowered into position.

Other objects and advantages will become more readily apparent when the following detailed description is read in connection with the accompanying drawings, in which:

FIG. 1 is a perspective view of the hot top partly broken away to show the combination casing, liner and bottom ring.

FIG. la is a perspective view of the casing partly broken away.

FIG. 2 is a top view of the bottom ring assembly with the wiper ring partly broken away.

FIG. 3 is a view of a section of the bottom ring assembly.

FIG. 4 is a front elevational view of the liner.

FIG. 5 is a side sectional view of the combination casing, liner and bottom ring assembly.

FIG. 6 is a side view of the wiper ring showing the flexibility feature.

FIG. 7 is a side sectional view showing the assembled hot top positioned in the top of an ingot mold.

Referring to the drawings, the hot top 10 shown in FIG. 1 is commonly referred to as a reuseable floating type hot top. In this respect the only reuseable portion of the hot top is the casing 12 which is a one-piece metal casting. A refractory bottom ring assembly 14 and a number of preformed refractory liners 16, 18 and 20 which line the inside wall surfaces of the casing and protect the bottom of the casing, are not reuseable. The unique combination of these three members to form the hot top is one of the primary concepts of the present invention which is considered inventive as will become more apparent hereinafter.

The hot top casing 12 is cast as a one-piece metal unit which is contrary to the present practice of using two or more metal sections which have to be assembled to form the hot top casing. Trunnions 22 are cast integral with the casing on opposite exterior walls of the casing for transporting the casings in the mill. The casing is cast with side walls 24, end wall 26 and corner walls 28 forming an eight-sided structure. Each of the walls has a wide base, 24b, 26b and 28b and tapers to a

narrow top

241, 261 and 281?. This results in a hot top having a greater volume at the bottom where it will be more readily available to feed into the ingot mold. The eightsided figure also eliminates to some extent the corners in the hot top where a substantial chill often occurs in the molten metal in the hot top and a reduction in the surface to volume ratio. This latter ratio is important since the molten metal which contacts the inside surface of the hot top will chill or solidify first, reducing the amount of molten metal which is available to flow into the ingot mold.

An inwardly projecting flange 30 is provided around the top of the casing and a groove 32 is formed on the lower inside surface of the flange. This groove extends around the entire periphery of the top of the hot top casing in straight line segments which are adjacent to the inside surface of the walls of the hot top casing. The bottom of the casing is provided with a short beveled surface 34 which cooperates with the bottom ring assembly in aligning it on the casing. Tapered lugs 35 are cast into the walls of the casing and are used to support the hot top on the top of the ingot mold when it is placed into position.

In assembling the hot top, the casing is turned upside down so that it rests on the flange on the top of the casing. The disposable or single use refractory liners 16s, 18s and 200 are then placed against the inside surface of the walls of the hot top casing and allowed to slide downward until the top 16t, 18t and 20t of the liners seats in groove 32 in the flange. Referring to FIG. 4, liner 16s for one of the side walls is shown. It should be noted that the top 161 is narrower than the bottom 16b and has an upper surface 15 which is beveled upward from the inside surface toward the outside surface. The edges 16d are also beveled from the inside surface outward toward the outside surface to interlock with the adjacent liners, forming a wedge fit or key when the last liner is inserted into the hot top casing. It is important for the boards to fit snugly in order to prevent any molten metal within the hot top from coming into contact with the casing. Since the molten metal in contact with the liners solidifies or chills first, a seal will form quickly along the abutting edges of the liners.

A flange 36 is provided across the bottom of each of the liners which will project slightly beyond the end of the casing when the boards have been firmly wedged into the hot top casing. In the present embodiment of the invention, a liner made of a refractory material held together with resin binder is contemplated. These liners because of their simple configuration can be easily manufactured in straight line core boxes and baked or solidified in a minimum of time. These core boxes can be made to any dimensions with little difficulty and produced on a mass production basis. Exo'thermic materials may be applied to the inside surface or may be mixed into the refractory material. As is well understood in the art, the exothermic materials will produce some heat along the walls of the hot top which will aid in keeping the metal molten within the hot top.

After the liners have been wedged into position in the hot top, the bottom ring assembly 14 is placed on the bottom of the hot top casing. The bottom ring assembly protects the bottom of the casing from the molten metal within the ingot and also supports a resilient type wiper ring 38 which bridges the gap between the hot top and the ingot mold wall to form a seal. Wiper rings are used to chill molten metal as it rises in the gap, thereby forming a seal which prevents leakage of molten metal from the ingot mold.

The bottom ring assembly includes a refractory ring 40 as well as the wiper ring. The refractory ring is formed of a refractory material held together with a binder and baked or otherwise solidified by a bonding action at the manufacturing point in the same manner as the liners. The refractory ring is formed in a core box with a flat bottom surface 42 and a side wall 44 which forms an acute angle of approximately 85 with the bottom surface.

The side wall is cut back to form a ledge 46 around the periphery of the ring and then extends upward, forming a flange 48 having upwardly sloping

walls

50 and 52.

' The top surface 54 of the ring is also flat and intersects wall 52 of the flange, forming a slightly arcuate gusset. The intersection of the top surface 54 and wall 52 of the flange conforms substantially to the shape of the bottom of the casing and the outer beveled surface 34. A groove 56 is formed in the top surface of the refractory ring with the outer edge 58 of the groove forming a continuation of the inside surface of the metal casing when assembled. The groove width is made substantially equal to the width of flange 36 on the liners. The inner surface 60 of the ring forms a continuation of the inner surface of the liner when assembled as in FIG. 5. It is important that the inner surface of the liners be coplanar with the inner surface 60 of the refractory ring or overlap slightly to prevent any interference with the molten metal that is initially poured into the ingot mold.

The wiper ring can be roll formed and stamped to produce the configuration shown in FIG. 5. The wiper ring base 62 and wiper ring side wall 64 intersect at an acute angle which conforms substantially to that of the base and outer surface of the refractory ring. When the wiper ring is securely overlapped and welded onto the refractory ring it will be securely locked onto the refractory ring. The wiper ring is made in two U-shaped sections and placed on the refractory ring with the ends of the sections overlapped. The sections are then preheated so that the overlapped sections expand slightly before spot welding. Once the spot welding operation has been completed, the sections are allowed to cool and shrink into tight engagement with the refractory ring with a consequent compression of the refractory ring.

The wiper ring is provided with two

independent wiper blades

65 and 67. The blades are formed by stamping the wiper ring so that wiper blade 65 angles outwardly and upwardly from the side wall and wiper blade 67 angles upwardly and inwardly toward the side wall. A slight clearance 70 (FIG. 6) is provided between the end of section 67 and side wall 50 to allow for a limited amount of flexibility in the wiper blade.

The preassembled bottom ring assemblies are attached to the casings by metallic spring clips 90 which are conventional in the art. The clips extend under the bottom ring assemblies and are snapped into anchor holes 100 provided in the walls of the casing. The body portion is generally bowed outward to produce a holding force when the spring clip is inserted into the anchor holes.

In review, the hot top is assembled by turning the casing upside down with the top resting on the floor. Disposable preformed refractory liners are placed against the inside surfaces of the casing and allowed to slide downward until the top of the liner seats in the groove in the flange. A preassembled bottom ring assembly is then placed on the bottom of the casing with flange 36 on the bottom of the liners seated in groove 56 in the refractory and the bottom of the casing aligned within the flange on the refractory ring. Spring clips are then used to secure the bottom ring assembly to the casing.

The hot top can then be picked up by the trunnions and transported to an ingot mold. Wooden wedges or blocks 37 are placed beneath the lugs to hold the hot top in position on the top of the ingot mold until the ingot is poured. The blocks can be cut to any convenient length and placed between the lug and the top of the ingot mold as shown in FIG. 7. At least two lugs are provided on each side of the casing to balance the hot top on the top of the ingot mold. Since the blocks are located on top of the ingot mold, they can be quickly and easily removed, allowing the hot top to float on the ingot. A substantial tolerance is provided between the hot top and the opening in the ingot mold. The flexible wiper ring is designed to compensate for this tolerance as well as to spring back into engagement with the sides of the opening in the event the hot top is bumped against the sides when it is lowered into position.

Although only one embodiment of the present invention has been shown and described, it should be apparent that various changes and modifications can be made therein without departing from the scope of the appended claims.

What is claimed is:

1. A hot top comprising:

a unitary cast metal casing having an open center which tapers from the top outwardly toward the bottom, an inwardly projecting flange around the top of the casing,

preformed single use refractory liners positioned within said casing with one end in abutting engagement with said casing flange and the other end terminating at the end of said casing, said liners including a flange projecting beyond the end of said casing,

a preassembled single-use bottom ring assembly secured to the bottom of said casing,

said assembly including a refractory bottom ring having a first portion projecting inward toward the center of said casing and underlying the other end of said liner,

said first portion including a groove below the upper surface of said ring for engaging said liner flange and holding said liners against said casing,

the inner peripheral surface of said first portion forming a continuation of the inside surface of said liner.

2. A hot top according to claim 1 wherein said bottom ring assembly includes a wiper strip secured to the outer periphery of said refractory ring,

said strip including at least one wiper blade extending upwardly and outwardly from the outer periphery of said refractory ring.

3. A hot top according to claim 1 wherein said bottom ring includes a ledge around its outer periphery,

said bottom ring assembly including a wiper ring having a V-shaped wiper blade integral therewith with the upper edge of said V-shaped blade resting on said ledge and being movable thereon to allow for limited motion in said blade.

4. A hot top comprising, in combination:

a one-piece metal casing, having interior side walls, end walls and corner walls, an inwardly projecting flange around the top of the casing, a groove in said flange,

one-use refractory liners positioned on each of said walls in abutting engagement with the adjacent liners and seated in said groove, each of said liners having a flange projecting beyond the end of said casing,

a bottom ring assembly including a single use refractory ring and a wiper ring,

said assembly being secured to said casing with said refractory ring projecting inwardly and underlying said liner,

said refractory ring including a groove below the upper surface of said ring with one wall of said groove in alignment with the inside surface of said casing and the inner peripheral surface of said refractory ring forming a continuation of the inner surface of said liner, said flange on said liner being seated in said groove.

5. A hot top according to claim 6 wherein the outer peripheral surface of said refractory ring includes a ledge,

and said wiper ring includes wiper blades at two different levels which intersect in a V-shape, the upper edge of one of said wiper blades resting on said ledge.

6. The combination with a one-piece hot top casing having preformed one-use liners positioned on the inner surface with a flange across the bottom of the liner projecting beyond the end of the casing, of means for interlocking the liners to the casing, comprising:

a bottom ring assembly secured to the casing and including a refractory ring having an open center and a wiper ring mounted on the outer periphery of said refractory ring,

said refractory ring projecting inwardly and having a groove in engagement with the flange on the liners with the inner surface of the ring forming a continuation of the liner, and

said refractory ring includes a relief ledge on its outer periphery,

said wiper ring having two wiper blades extending outwardly from the wiper ring with one of said blades resting on said ledge.

References Cited UNITED STATES PATENTS 1,665,515 4/ 1928 Trembour 249201 1,921,729 8/ 1933 Charman 249201 3,110,942 11/ 196-3 Thiem et al. 249202 3,239,187 3/1966 Daley 249202 3,352,530 11/ 1967 Thiem 249202 .T. SPENCER OVERHOLSER, Primary Examiner. EUGENE MAR, Assistant Examiner.

us. c1. X.R 249202 U.S. DEPARTMENT OF COMMERCE PATENT OFFICE Washington, D.C. 20231 UNITED sTA Es PATENT' O F CE CERTIFICATE OF CORRECTION Patent No. 3,437,308 April 8 1969 Darold W. Thiem et al.

It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

' Column 6, line 28, claim reference numeral "6" should read 4 Signed and sealed this 27th day of October 1970.

.(SEAL) Attest:

Edward M. Fletcher, Jr. WILLIAM E. JR.

Attesting Officer Commissioner of Patents