US3210810A

US3210810A - Apparatus for forming a hot top

Info

Publication number: US3210810A
Application number: US280903A
Authority: US
Inventors: Potter Horace Westphul
Original assignee: Lukens Steel Co
Current assignee: Lukens Inc
Priority date: 1963-05-16
Filing date: 1963-05-16
Publication date: 1965-10-12
Anticipated expiration: 1982-10-12

Description

Oct. 12, 1965 H. w. POTTER 3,210,810

APPARATUS FOR FORMING A HOT TOP Filed May 16, 1965 4 Sheets-Sheet l INVENTOR HORACE w POTTER.

ATTORNEYS Oct. 12, 1965 Q w. POTTER 3,210,810

APPARATUS FOR FORMING A HOT TOP Filed May 16, 1963 4 Sheets-Sheet 2 INVENT OR HORACE W POTTER ATTORNEYS Oct. 12, 1965 H. w. POTTER 3,210,810

APPARATUS FOR FORMING A HOT TOP Filed May 16, 1963 4 Sheets-Sheet 5 INVENTOR HORACE W POTTER ATTORNEYS Oct. 12, 1965 H. w. POTTER 3,210,810

APPARATUS FOR FORMING A HOT TOP Filed May 16, 1963 4 Sheets-Sheet 4 INVENTOR HORACE W POTTER ATTORNEYS United States Patent O 3,210,810 APPARATUS FOR FORMING A HOT TOP Horace Wesiphui Potter, Ooatesville, Pa., assignor to Lukens Steel Company, Coatesville, Ia., a corporation of Pennsylvania Filed May 16, 1963, Ser. No. 280,903 1 Claim. (Cl. 22-9) This invention relates to a simplified method and apparatus for forming a hot top in an ingot mold. More particularly, the invention is directed to the employment of a rigid core box with an elastic expansible tube member provided around its lower aspect to seal the bottom portion of the hot top mold area, in the process of making hot tops in ingot molds having open bottoms wherein the core box with the tube are dropped to the bottom of the ingot mold after the hot top has been completed.

The present state of the art for the forming of hot tops within ingot molds wherein a hardening fluid is injected into the mass which will make up the hot top, is exemplified by Patent No. 3,077,646, of February 19, 1963 to Bo Magnus Tigerschiold and a co-pending application, Serial No. 262,415 filed March 4, 1963, of Joseph D. Karmerze et al. Disclosed in the foregoing are core boxes comprising collapsible forms, known in the art as umbrellas, which are inserted into the top of the ingot mold and opened against the sides thereof to form a trough between the umbrella and the inner sides of the ingot mold. A hardenable mass is subsequently placed in this trough and a hardening fluid is injected therethrough through orifices in the sides of the umbrella. When the hot top has become hard, the umbrella is collapsed and pulled up and out of the ingot mold. The umbrellas employed in such methods have a number of moving parts. They represent a substantial investment, costwise initially and for maintenance, subsequently. The umbrellas are heavy and have to be handled by chain hoists to place them in position. From time to time, some of the hardenable mass will tend to become stuck within the orifices in the molds side and thereby block the passage of hardening fluid in subsequent usage unless cleaned out. Ingot molds frequently have vertical furrows provided along their inner edges and the crosssection of the mold tends to taper outwardly from the top to the bottom. Since the umbrella is not always placed in the same level in an ingot mold, it will, therefore, be appreciated that the skirts of the umbrella will not cover the entire bottom of the mold. As a result, there are usualy some rough spots left in the mold area where the skirts of the umbrella fail to contact with the inner sides of the ingot mold. A uniform injection pattern of the hardening fluid into the hardenable mass is difficult to obtain about the corners of the umbrellas presently used since the corners move relative to the sides; their relative positions being variable and thus the distances between adjacent orifices varying for different cross-sectional area of the ingot mold involved.

It is an object of this invention to provide an effective hot top mold without moving parts.

A further object of the invention is to render the method of making hot tops in bottom-pour ingots more economical by reducing the cost of the forms and the maintenance thereof.

A further object of this invention is to provide in the process of making hot tops by the injection of a hardening fluid such as carbon dioxide into the hot top mix, means for cleaning the orifices from which the hardening fluid is injected, of such refractory material and the like as may become lodged therein.

An additional object of the invention is to reduce the weight of the apparatus used in forming a hot top in a bottom-pour ingot mold without a corresponding reduction in the strength of such apparatus.

A yet further object of the invention is to provide a core box in the apparatus for forming a hot top which will conform to furrows in the inner sides of ingot molds, thereby improving the quality of the hot top which is formed.

A still further object of the invention is to improve the uniformity of the injection of the hardening fluid into the mass which makes up the hot top.

And a further object of the invention is to provide a core box which is more adaptable to the different crosssectional areas in the ingot mold openings which vary with the depth wherein it is desired to place the hot top.

Further objects will appear as the description progresses, reference being had to the accompanying drawings in which:

FIGURE 1 is a vertical section of the invention in place in a bottom-pour ingot mold;

FIGURE 2 is a partial horizontal section taken on the sectional lines 22 of FIGURE 1;

FIGURE 3 is a prespective view of the support stand for the core box of the invention in place on top of the ingot mold;

FIGURE 4 shows support members and a stand which may be provided for the embodiment shown in FIG- URE 1;

FIGURE 5 is a vertical section similar to FIGURE 1 showing a further embodiment of the invention;

FIGURE 6 is a perspective view of the support stand for the core box on the top of an ingot mold;

FIGURE 7 is a top view of the ingot mold and stand shown in FIGURES 5 and 6;

FIGURE 8 is a perspective view of the core box shown in FIGURES 5-7; and

FIGURE 9 illustrates how several of the core block boxes shown in FIGURE 8 can be stacked to save space.

I-Iot tops generally consist of a refractory material, such as sand, and may be placed on top of the mold, inserted partially into, or entirely into the mold. The function of the hot top is to contain the shrinkage cavity which occurs as the ingot cools in the ingot mold and minimize the loss of steel around the cavity which must be discarded.

The hot top made by the apparatus in method of the instant invention, is composed usually of a mix of primarily sand, moisture and sodium silicate. This mixture is placed in the trough formed between the core box in the ingot mold where it is leveled and tamped. Carbon dioxide is then injected into this mix which causes it to harden. The core box is then withdrawn and, where a bottom-pour mold is employed, such mold is transferred to a suitable surface whereby molten steel may be introduced into the mold through its open bottom portion.

Referring now to the drawings, the trough to contain the hot top mass of refractory material is designated by numeral 10. The core box, designated generally by numeral 11, is positioned within the bottom-pour ingot mold 12. It is held in place by means of a stand 13 through a pair of hook members 15 which engage eyes 16 secured to the cross bar 17 of the core box 11. The core box 11 is in the shape of a truncated pyramid which is open both at the top and the bottom. The sides of the core box 11 constitute inner walls 2i) and outer walls 21 which have a plurality of uniformly spaced outlet orifices 22. The

walls

20 and 21 completely surround a plenum chamber or interior space 23. A first conduit member 24 leads from the tank of hardening fluid such as carbon dioxide under pressure (not shown). Conduit 24 includes a coupling member 25, a valve 26 and, within the further conduit to interior space 23, an inlet valve 27. Conduit 24, together with the interior space 23 and the outlet orifices 22, comprise the hardening fluid supply supply means to the hot top mass in trough 10.

An elastic tube member 30 is disposed around the periphery of the foot of the core box 11 within a U-shaped channel member 31 provided for this purpose. This channel member 31 is connected to the walls and 21 by welding or other suitable means. The tube 30 is vulcanized to the upper limb 32 of the channel member 31 and a graphite lubrication is provided between the tube 30 and the lower limb 33 of the member 31. A pad 29 is afiixed to the bottom of limb 33.

A second conduit member 34 leads through the wall of the U-shaped channel member 31 into the interior of the tube 30. Conduit member 34 constitutes a fluid supply means to introduce fluid (compressed air, in practice, for economy reasons) into the tube 30 whereby it may be inflated to seal and from the bottom portion of the trough for reception of the hot top mix in trough 10. The conduit member 34 contains a cut-off or compressed air valve 35 and a seal inlet valve 36. A cross-over conduit line 37 is provided between the first conduit member 24 and the second conduit member 34. The crossover conduit 37 connects into the first conduit member 24 between the

valves

26 and 27, and into the second conduit member between the

valves

35 and 36. The cross-over conduit line 37 contains a cross-over valve 40. Also located between the

valves

35 and 36 on the second conduit member 34 is a seal release line 41 which contains a seal release valve 42.

The open bottom ingot mold 12 has a plurality of ingot mold lift hooks 43, and its inner side 44 has a plurality of longitudinal furrows 45. The bottom surface 46 of the ingot mold rests upon a surface which does not constitute part of the mold per se.

The stand 13 comprises two standards 47 and 47A which have welded across their upper portions a pair of horizontal angle irons 50 and 51. Two plates 52 and 53 are welded between the angle irons 50 and 51. The plate 52 has approximately in its center an opening 54 which receives a hook member 15. Similarily, plate 53 has an opening 55 which also receives a like hook member 15. Each hook member 15 is provided with a collar clamp 56 incorporating a screw member 57 which can be turned in a threaded opening in a collar clamp 56 to bear against the hook member 15 and lock itself rigidly therewith. The collar clamps 56 rest upon plates 52 and 53, and it will be appreciated that by adjusting the position of the collar clamps 56 on the hook members, the level of the core box 11 within the ingot mold 12 is selectively adjustable within limits. The transverse placement of the core box 11 depends upon the positioning of stand 13 on the top of the ingot mold 12. A crane hook 60 is adapted to receive the crane lift 61; the crane hook 60 being welded to the top of the cross bar 17.

In operation, the stand 13 is placed over the core box 11 so that the hook 60 protrudes through space 49 bounded by angle irons 50 and 51, and plates 52 and 53. Hook members 15 are positioned in the eyes 16 and collar clamps 56 are locked thereon against the plates 52 and 53. Crane lift 62 then engages the crane hook 60 and carries the core box 11 together with the stand 13 to the ingot mold 12 where it is lowered into the top portion of such ingot mold. The stand 13 should be positioned, when this is accomplished, so that the core box is centrally located with respect to the inner sides 44 of the ingot mold 12. The collar clamps 56 are then loosened and the core box 11 is lowered by means of the crane lift 61 to its desired level in ingot mold 12, at which time the collar clamps 56 are again locked with respect to the hook members 15. The first conduit member 24 is then coupled together by coupling member and the second conduit member 34 is coupled together by coupling member 39. Assuming that all valves are initially closed,

valves

35, 40 and 27 are first opened so that compressed air from the second conduit means is lead through the cross-over conduit 37 into interior space 23 to blow out any dirt, left-over sand, or the like in space 23 and in outlet orifices 22. This cleaning process also tends to clean the inner sides 44 of the upper aspect of the ingot mold 12, and upper limb 32, and to a certain degree, the upper portion of tube member 30. Valve 40 is then closed and valve 36 opened to inflate the tube 30 against the inner sides 44 of the ingot mold 12. As can be seen from FIGURE 2, the tube 30 will inflate so as to make continuous contact with the inner sides 44, even within the furrows 45. Inflation of the tube member 30 also tends to center the core box 11 within the ingot mold 12 and its gripping action provides additional support for the core member 11. When the tube 30 is inflated to the desired degree, the valve 35 may be closed. The mix of sand, sodium silicate and moisture is then placed in the trough 10 formed by the inner sides 44, the outer walls 22, the upper limb 32, and the upper portion of the tube 30. This mixture is tamped and smoothed 0n the top. A fluid comprising carbon dioxide is then supplied by opening valve 26 to the first conduit member 24 at a pressure of approximately 25 to 50 pounds per square inch to permeate the mix. When this is accomplished, the valve 26 is closed. Collar clamps 56 are then loosened, the sources of carbon dioxide and compressed air are cut off, and the

couplings

25 and 35 are disconnected. The seal release valve 42 is then opened and air escapes from the tube 30 through the seal release line 41 which causes tube 30 to collapse. The core box 11 will then fall of its own weight to the position shown in dotted lines in FIGURE 1 at the bottom of the ingot mold unless held in place by the grip of the hot top mass in trough 10 on sides 22 in which case a few hammer taps on the top of hook are usually suflicient to cause the core box to drop. The shock of the fall on core box 11 is somewhat cushioned by pad 29. Subsequently, the ingot mold 12 is lifted by means of its lift hooks 43, together with the incorporated hot top mass, and moved to a place where the bottom pouring procedure is accomplished. At this time the core box 11 is recovered.

FIGURE 4 illustrates a support member which may be secured to the core box 11 whereby the core box may be conveniently stored when not in use on a stand 71. A pair of I-beams 72 are Welded or otherwise secured to the cross bar 17. Four vertical legs 73 (only two shown in FIGURE 4) are welded or otherwise secured to the ends of the I-beams 72. At the bottom of the legs 73 a further pair of I-beams 74 are welded or otherwise secured. Cross beams 75 secure adjacent legs 73 as additional strength members. The I-beams 74 rest on a pair of stands 71. Stands 71 may be separate or may be welded in place to I-beams 74. In the event that they are welded in place, pads 76 are provided on the lower aspects of stands 71 to cushion the fall of the core box 11 when it is dislodged after producing a hot top, and pads 29 are not needed in this modification.

FIGURES 5-8 show a modified core box 80 and stand 81 positioned in the ingot mold 12. The core box 80 is similar to the core box 11 in that it has an inner wall 82 and outer wall 83; the outer wall 83 including a plurality of uniformly spaced outlet orifices 84. The walls 82 and 83 surround a plenum chamber or interior space 85 similar to space 23 in core box 11. In the lower portion of the core box 80, there is a portion 86 wherein the inner and outer walls 82 and 83 together with the interior space 85 flare outwardly. Except for the orifices 84 and an inlet 87, it will be appreciated that the interior space 85 is completely surrounded by the walls 82 and 83.

An elastic expansible tube member 90 is vulcanized to the inner Wall 82 inside the flared portion 86. The intcrior space 91 is completely surrounded by the tube 90 except for an inlet 92.

The stand 81 includes four sloping legs 93 each having shoes 94 applied to the lower terminal ends thereof. The

legs 93 carry a support tube 95 which is sealed at its ends by caps 96. Leading from the support tube 95 are four lines, 100, 101, 102 and 103. Each line includes a

coupling member

104, 105, 106 and 107. Also disposed in each line between the coupling member and the support tube are

valves

110, 111, 112 and 113. Contained in the support tube 95 and interposed between

lines

100 and 101 on one hand and 102 and 103 on the other hand, is a cross-over valve 114.

A first conduit member 115 is connected to a supply of hardening fluid, usually carbon dioxide, and leads through coupling member 104, line 100 containing valve 110, tube 95, line 101 containing valve 111, coupling member 105, spacer hose 116, and coupling member 99, to inlet 87 of interior space 85. A second conduit member 117 leads from a further fluid supply, compressed air. Conduit 117 leads compressed air through coupling 106, line 102 containing valve 112, tube 95, line 103 containing valve 113, coupling 107,and hose 120 to inlet 82 of tube 90. Connected into line 103 below the valve 113, is a seal release line 121 which incorporates a seal release valve 122. The hose 120 is held near the inner wall 82 of the core box 80 by means of a holding bracket 123 which connects to the inner wall and embraces the hose.

The core box 80 has welded in its corners four support beams 124 which slant inwardly and upwardly with respect to the core box 80 to the core box hook 125 where they connect to each other and to said hook 125. The support tube 95 has centrally located on its upper side a crane hook 126 and on its lower side a support hook 127. A connective member 130 connects hooks 127 and 125. The connective member 130 comprises a shackle 131 which depends from a link chain 132. The opening 133 in support hook 127 incorporates a slot 134 whereby the length of the chain 132 which depends from the hook 127 may be adjusted and the chain may be secured.

In operation, a crane lift 61 will first engage hook 126 of stand 81 and lift same to the vicinity of the core box 80, then in its place of storage. Portions of core box 80 are then connected to stand 81 through

couplings

99, 105 and 107, spacer hose 116, and connective member 130. Lift crane 61 then raises the stand 81, together with the core box 80, and the assembly is placed on the ingot mold 12. When in this position, the core box 80 is centered in the opening of ingot mold 12 by positioning the stand 81 correctly on the upper portion of the ingot mold and the desired level on the core box 80 is obtained by adjusting the depending length of the chain 132 from the slot 134. If necessary, the core box 80 can be supported by means of the crane lift 61 engaging the core box hook 125 while the length of the chain 132 is adjusted. Once the core box 80 is in its desired position, assuming all of the valves to be initially closed, the compressed air valve 112, the cross-over valve 114, and the carbon dioxide inlet valve 111, are opened. This permits the passage of compressed air through conduit 117 into the support tube 95 and finally through the lower portion of conduit member 116 into the interior space 85 of the core box. The compressed air is thus ejected from the outlet orifices 84 and dirt, sand, and the like which may have lodge in the orifices is blown out. There is also a cleaning effect upon the adjacent inner wall 44 of the mold. Following this step, the cross-over valve 114 is closed and a seal inlet valve 113 is opened whereby compressed air inflates tube 90 so that tube 90 is forced into contact with the inner sides 44 of the ingot mold 12, thus effecting a seal in the lower portion of the trough which will receive the mix for the hot top mass. As will be noted from FIGURE 7, the inflated tube completely seals the intervening space between the sides 44 and the core box 80, including the spaces in the furrows 45. When the core box is so positioned, the mix for the hot top mass 10 is placed and tamped in the trough between the core box 80 and the ingot mold 12, as described previously. The carbon dioxide valve 110 is then opened for an appropriate time to gas the mix and cause the hot top mass in trough 10 to harden. After the mass is hardened, air is released from the interior 91 of tube 90 by closing valve 112 and opening the seal release valve 122.

Couplings

99 and 107 are then released and shackle 131 is disengaged from hook 125. The core box is then free to drop to the bottom of the ingot mold. The fall of the core box is cushioned by the tube which has some residual air left in it. Subsequently, the ingot mold 12 together with the hot top mass in place is removed to another location by means of lifts 43, at which time the core box 80 is recovered. An advantage of the structure of this embodiment lies in the fact that a number of individual core boxes 80A can be stacked one on the other as shown on FIGURE 9.

It will be noted in both embodiments, particularly from the core box shown in FIGURE 8, that the orifices 84 can be located in a manner wherein they are uniformly spaced from each other. Such uniform spacing is not shown in the prior art. However, it will also be appreciated by those skilled in the art that the design also permits a non-uniform spacing wherein more orifices per unit area are intentionally provided in the lower portion of the core box than in the upper portion. For illustrative purposes this is shown in core box 80A in FIGURE 9.

The foregoing detailed description has been given for clearness and understanding only, and no unnecessary limitations should be understood therefrom, for modifications will be obvious to those skilled in the art.

I claim:

For use in the process of forming a hot top within an ingot mold, a form which comprises a core box which is open at the top and bottom, the sides of said box having inner and outer walls surrounding an interior space, a plurality of fluid outlet orifices disposed in said outer Walls, first fluid supply means for selectively supplying fluid under pressure to the aforesaid interior space and through said orifices said first fluid supply means including a first tank and a first conduit member, said first fluid supply means including an inlet into the upper portion of said interior space, the areas of said orifices to the area of said outer wall being greater in the lower portion of said core box, an elastic tube member connected around the lower periphery of said box, second fluid supply means for selectively supplying fluid under pressure to the interior of said tube, said tube thereby being expansible between said box and the inner sides of an ingot mold, whereby a hot top mold may be formed between the form and the inner sides of the associated ingot mold, said second fluid supply means including a second tank and a second conduit member, said first and said second conduit members being joined by a further cross-over conduit, all of said conduit members having at least one valve disposed therein whereby fluid may be selectively led from said first tank to said second conduit and from said second tank to said first conduit.

References Cited by the Examiner UNITED STATES PATENTS 1,636,243 7/27 Rasmussen 25-127 2,663,919 12/53 Lentz 22-37 2,682,690 7/ 5 4 Worthington 22-36 3,077,646 2/63 Tigerschiold 22-147 3,100,919 8/63 Vayda 22-9 3, 107,402 10/ 63 Hunter 22-10 3,154,816 1 1/ 64 Harrison et a1. 264-269 3,171,169 3/65 Graef 22-9 FOREIGN PATENTS 638,667 3/ 62 Canada. 1,262,217 4/ 61 France. 1,149,502 5/63 Germany.

885,436 12/ 61 Great Britain.

MARCUS U. LYONS, Primary Examiner.