US2962778A

US2962778A - Pouring control for aluminum ingots

Info

Publication number: US2962778A
Application number: US687319A
Authority: US
Inventors: William M Peak; Wade James
Original assignee: Individual
Current assignee: Individual
Priority date: 1957-09-30
Filing date: 1957-09-30
Publication date: 1960-12-06
Anticipated expiration: 1977-12-06

Description

W. M. PEAK ETAL POURING CONTROL FOR ALUMINUM INGOTS Dec. 6, 1960 3 Sheets-Sheet 1 Filed Sept. 30, 1957 INVENTORS M/mm 3 4 James M09 (/ZWMJQ Dec. 6, 1960 w. M. PEAK ET AL 2,962,778

POURING CONTROL FOR ALUMINUM INGOTS Filed Sept. 30, 1957 5 Sheets-Sheet 2 INVENTORS. ////'avfl 44 Peak Dec. 6, 1960 w. M. PEAK ET AL POURING CONTROL FOR ALUMINUM INGOTS 3 Sheets-Sheet 3 Filed Sept. 30, 1957 William M. Peak, Valleyford, Wash., and James Wade, S. 411 Sheridan, Spokane 3, Wash.

Filed Sept. 30, 1957, Ser. No. 687,319

3 Claims. (Ci. 22-79) The present invention relates to improvements in means for controlling the flow of molten metal from a trough into an ingot mold. In the manufacture of certain metal products such as sheet metal and the like, and particularly in the manufacture of sheet aluminum, one step of the manufacture process involves the formation or molding of large ingots of metal which are later rolled out into thin sheets. These ingots are formed by pouring molten metal into a mold and cooling it to a solid state. The formation of the ingotis a difficult and exacting process in that an acceptable ingot must be entirely homogeneous, and must be uniform throughout its mass in all respects.

One of the present methods of forming a commercially acceptable ingot is to utilize a vertically shallow four sided ring mold having an open top and an open bottom, together with a vertically movable bottom closure plate below the mold. The bottom closure plate is initially brought into position to close the bottom of the ring and molten metal is poured into the ring. As the metal is poured in the top of the ring, the bottom closure is lowered away at a constant rate. The lowering is timed so that the metal solidifies while confined within the ring mold and the solid ingot is withdrawn from the bottom thereof. By using this method it is :possible to form ingots of very large dimensions which are homogeneous and uniform throughout their mass. This method successfully overcomes the problem of non-uniformity due to unequal cooling which is encountered in molding large objects by pouring molten metal into a stationary mold and allowing it to cool in the mold.

In carrying out the ingot molding process described above, it is essential that the flow of liquid into the ring mold be carefully controlled tomaintain the liquid level in the mold stationary. *If the flow of liquid is reduced, and'the liquidlevel in the mold drops off, or if the flow ofliquid is increased and the liquid level in the mold is allowed to rise, then the ingot withdrawn from the bottomof the mold will not be entirely uniform. It is the principal purpose of'this invention to provide a control apparatus to control the flow of molten metalfrom a supply trough into the ring mold, to maintain the liquid inthe ring mold at a constant level. More specifically it is the purpose of this invention to provide a novel and simple device for controlling the flow of molten metal "from asupply trough into amold which is operably responsive. to the level of liquid in the mold to increase or decrease the flow of metal according to variations in the liquid level in the mold.

The nature and advantages of our invention will appear more clearly from the following description and the accompanying drawings wherein a preferred form of the invention is shown. It shouldbe understood, however, that "the description and drawings are illustrative only and are not intended to limit the invention except insofar as itis limited by the claims.

ice

In the drawings:

Figure 1 is a perspective view illustrating an ingot mold, together with a molten supply trough, and illustrat ing our invention in place to control the flow of molten metal from the trough into the mold;

Figure 2 is an enlarged vertical sectional view taken substantially on the line 22 of Figure 1;

Figure 3 is a vertical sectional view taken onthe line 3-3 of Figure 2; and

Figure 4 is a fragmentary sectional view taken substantially on the line 4-4 of Figure 2.

Referring now in detail to the drawings, we have shown, somewhat diagrammatically, an ingot mold, generally indicated by the numeral 10, of the type currently in use in the aluminum industry for forming ingots of large dimensions. The mold 10 comprises a four sided ring 11, the top and bottom of which are open, together with a horizontal bottom closure plate 12, mounted on the piston 13 of an hydraulic cylinder 14. The plate 12 is adapted to be moved up and down below the ring 11 by operation of the cylinder 14.

In the formation of an ingot, such as that indicated by numeral 15, the closure plate 12 is initially moved up against the bottom edge of the ring 11, and molten aluminum is poured into the ring 11 from the open top. When the molten metal has reached a predetermined level in the ring 11, the cylinder 14 is activated to commence lowering the closure plate away from the ring 11 at a predetermined steady rate. Molten aluminum is continuously poured into the top of the ring 11 at such a rate as to maintain the level in the ring 11. stationary. A boX like bafiie member 16, having liquid discharge openings 17 at its ends, is suspended in the open top of the ring 11 to receive the molten metal poured into the top of the ring 11 and deflect it laterally toward the ends of the ring to insure that the ring is filled evenly. The rate at which the plate 12 is lowered is determined by the rate of cooling of the molten metal, and is adjusted so that a layer of metal poured into. the ring 11 cools sufiiciently during its downward movement through the ring 11 to substantially solidify while still confined within the ring 11, sothatas the closure plate 12 is lowered, a solid ingot is withdrawn from the bottom of the ring 11.

The ring 11 may, of course, be cooled, and cooling means may be provided below the ring 11 to lower the temperature of the solid ingot, if desired. No such means have been shown in the drawings, since the details of construction and operation of the mold 10 form no part of the invention. Molds of the type hereinbefore described are well known in industry.

In order to convey molten metal from the furnace (not shown) wherein it is heated to a molten state to the mold 10. trough means are provided. A supply trough 18 is provided into which molten aluminum is spilled from the furnace by some suitable means. The supply trough 18 has adelivery trough 19 connected thereto which carries the molten metal from the supply trough 18 to the mold 10. As shown in Figure l, the delivery trough 19 is pivotally connected to the supply trough 18 by pivot means 20 whereby to be pivoted laterally to serve several molds 10.

It will be appreciated that maintenance of a constant liquid level in the ring 11 is of utmost importance in the formation of an acceptable ingot. If the level in the ring 11 is allowed to rise or fall because of improper adjustment of the rate of flow of metal from the trough 19, a non-uniform ingot will be produced. It is therefore necessary to provide on the delivery trough 19, means to regulate the flow of metal-therefrom intothe mold 10 in response to level variations in the ring 11.

According to our invention, we accomplish this result by providing in the bottom of the trough 19 adjacent the discharge end thereof, a downwardly directed conical spout 21 adapted to pass molten metal from the trough downwardly into the bafile box 16 of the mold 10. An upright cylindrical rod 22 is provided in the trough 19 in vertical alignment with the spout 21. The rod 22 is smaller in diameter than the upper end of the spout 21 but greater in diameter than the lower end thereof so that it may be lowered into engagement with the conical wall of the spout 21 to close it. The bottom end of the rod 22 is rounded or bevelled as shown in Figure 2, to seal tightly against the spout 21 when it is lowered into engagement therewith. By moving the rod 22 vertically with respect to the spout 21 it is posible to accurately control the flowof molten metal from the trough 19 into the bafile box 16.

To support the rod 22, we provide a frame 23 which is adapted to be clamped to the trough 19 above the spout 21. The frame 23 comprises a pair of spaced apart transversely extending

members

24 and 25 which have their opposite ends turned downwardly as shown at 26 and 27. The

members

24 and 25 are connected together near one end by a bar 28, and near the other end by an upstanding inverted V-shaped yoke 29. The downturned ends 27 of the

members

24 and 25 have clamping bolts 30 threaded therethrough. The frame 23 rests upon the trough 19 as shown best in Figure 1, with the

members

24 and 25 extending across between the side walls thereof. The walls of the trough 19 are clamped between the downturned ends 26 of the

members

24 and 25 and the bolts 30 and the frame 23 is thus held securely in place.

The upstanding inverted yoke 29 on the frame 23 pivotally supports a pair of control arms 31 and 32 which extend transversely over the frame 23. As illustrated best in Figure 2, each of the control arms 31 and 32 has a series of apertures 33 near the center thereof, one of which receives a pivot pin 34 secured in the top of the yoke 29. A split clamping sleeve 35 is positioned between the ends of the control arms 31 and 32 which extend over the trough 19. The sleeve 35 has outwardly projecting pins 36 fixed thereon as shown in Figure 4, which extend through one of a series of holes 37 in the arms 31 and 32 to pivot the sleeve 35 between the ends of the arms 31 and 32. The sleeve 35 is clamped around and supports the rod 22. It will be understood that with this construction, movement of the control arms 31 and 32 about the pivot pin 34 results in vertical adjustment of the rod 22 with respect to the spout 21 and consequently, causes adjustment of the flow of molten metal therethrough.

In order to actuate the control arms 31 and 32 in response to level variations in the ring 11, a float generally indicated at 38 is provided. The float 38 is connected to the lower end of a rod 39 which extends upwardly between the outer ends of the control arms 31 and 32. The rod 39 has a threaded portion 39a thereon which receives a threaded sleeve 40. The sleeve 40 is provided with pivot pins 41 which are journalled in one of a series of apertures 42 in the arms 31 and 32 to pivotally connect the float rod 39 to the arms 31 and 32.

The operation of our invention is very simple. The float 38 is allowed to contact and be supported by the molten aluminum in the ring 11.. The float .rod 39 and the rod 22 are then adjusted so that when the level in the ring 11 is at the proper point, the flow of molten metal through the spout 21 is just suflicient to maintain the level in the ring 11 constant as the closure plate 12 is lowered away. When these adjustments have been made, the apparatus will operate to maintain this level throughout the pouring operation. If for any reason, the level in the ring 11.tends to rise, the float 38 will be elevated, and this motion will be transmitted through the rod 39 and the arms 31 and 32 to lower the rod 22 and cut down the flow through the spout 21. If for any reason the metal in the ring drops below the proper level, the float will drop also and raise the rod 22 to increase the flow through the spout 21. The rod 22, being thus operatively responsive to even the slightest varaiation in the liquid level in the ring 11, operates continuously to adjust the flow through the spout 21 to maintain the proper level in the mold.

It will be appreciated that since the spout 21, rod 22, and float 38 are constantly in contact with molten aluminum, or molten aluminum alloys, the temeperature of which is considerably in excess of 650 degrees C., they are maintained at approximately the same temperature. It has been found that steel possesses the proper characteristics for use at such temperatures, and in the aluminum industry, the molten metal carrying troughs such as the trough 19 and pouring spouts such as the spout 21, are commonly formed of this metal. We have found, however, that the rod 22 should not be made of steel. At the temperatures at which the spout 21 and rod 22 are maintained, a steel rod such as the rod 22 tends to stick to the spout 21 when it is brought into contact therewith, and some jarring force is necessary to break it away. Carbon does not exhibit this sticking tendency, and we have found that if the rod 22 is formed of this material it will move into and out of engagement with the steel spout 21 freely, even when both are heated to the temperatures they attain during the pouring operation. Accordingly, the rod 22 of our invention is formed of carbon.

In order for our flow control device to operate, it is necessary that the float 38 and rod 39 be heavy enough to overbalance the weight of the rod 22. The float 38, however, must be light enough to float on the molten metal in the ring 11. We have found that a hollow steel can forms a satisfactory float 38. Since the float 38 is hollow, and since it is subject to wide temperature variations, it is desirable to provide vent means in the float 38 to prevent undue stresses caused by air pressure therein. This is accomplished by providing an axial venting aperture 43 in the float rod 39 opening at the bottom into the interior of the float 38. This aperture.

43 permits free air movement into and out of the float 38.

While we have shown the float 38 formed as a hollow steel can, we do not wish to be limited to this construction. The float 38 may also be provided in solid form, and may be formed of carbon as well as steel. Weights, such as those indicated at 44 in the drawings may be used to obtain the proper balance.

It is believed that the nature and advantages of our invention appear clearly from the foregoing.

Having thus described our invention, we claim:

1. In aluminum ingot molding apparatus including a ring mold having an open top and bottom, a vertically movable bottom closure plate below the ring mold, means supporting said closure plate for vertical movement toward and away from said ring mold, a baffle box suspended within the ring mold, and a delivery trough for delivering molten metal through the baflie box to the mold, the improvement in means to control the flow of molten metal from the trough into the mold comprising a conical spout in the bottom of the trough, the walls of said spout converging downwardly, an upright cylindrical rod in the trough in substantial vertical alignment with the spout and extending into the spout, arm means pivotally supporting said rod, a frame resting on the trough above the spout and having means thereon to secure it to the trough, upstanding arm support means projecting upwardly from. the frame adjacent to one side of the trough, said arm means being pivoted intermediate the ends thereon on said arm support means at a point spaced from the rod, and float means in the mold supported in floating position by the molten metal in the mold movable vertically in response to changes in the level of the metal in the mold, said float means being connected to the arm means at the end thereof opposite the rod, said float means being heavier than the rod whereby to overbalance it and to move the rod vertically with respect to the spout to vary the flow of metal through the spout in response to level variations of the molten metal in the mold.

2. In aluminum ingot molding apparatus including a ring mold having an open top and bottom, a vertically movable bottom closure plate below the ring mold, means supporting said closure plate for vertical movement toward and away from said ring mold, a baflle box suspended within the ring mold, and a delivery trough for delivering molten metal through the baflle box to the mold, the improvement in means to control the flow of molten metal from the trough into the mold comprising an elongated tapered outlet in the bottom of the trough above the mold, the outlet decreasing in cross-section downwardly, an upright rod of uniform cross-section in substantial vertical alignment with the outlet, said rod being movable upwardly and downwardly in the outlet to increase and decrease the outlet area, arm means pivotally supporting said rod, a frame resting on the trough above the tapered outlet and having means thereon to secure it to the trough, upstanding arm support means projecting upwardly from the frame adjacent to one side of the trough, said arm means being pivoted intermediate the ends thereof on said arm support means at a point spaced from the rod, and float means in the mold supported in floating position by molten metal in the mold and movable vertically in response to changes in the level of the metal in the mold, said float means being connected to the arm means at the end thereof opposite the red, the float means overbalancing the rod whereby to move the rod vertically with respect to the outlet to increase and decrease the outlet area in response to downward and upward movement of the float whereby to reduce the flow of metal from the outlet when the level in the mold rises and to increase the flow of metal from the outlet when the level in the mold drops.

3. In aluminum ingot molding apparatus including a ring mold having an open top and bottom, a vertically movable bottom closure plate below the ring mold, means supporting said closure plate for vertical movement toward and away from said ring mold, a baflle box suspended within the ring mold, and a delivery trough for delivering molten metal through the bafile box. to the mold, the improvement in means to control the flow of molten metal from the trough into the mold comprising an elongated tapered outlet in the bottom of the trough above the mold, the outlet decreasing in crosssection downwardly, an upright carbon rod of uniform cross-section in substantial vertical alignment with the outlet, said rod being movable upwardly and downwardly in the outlet to increase and decrease the outlet area, arm means pivotally supporting said rod, a frame resting on the trough above the tapered outlet and having means thereon to secure it to the trough, upstanding arm support means projecting upwardly from the frame adjacent to one side of the trough, said arm means being pivoted intermediate the ends thereof on said support arm means at a point spaced from the rod, and float means in the mold supported in floating position by molten metal in the mold and movable vertically in response to changes in the level of the metal in the mold, said float means comprising a hollow metal can and an upright tubular vent pipe fixed to said can, said vent pipe being pivoted to the arm means at the end thereof opposite the rod, the float means overbalancing the rod whereby to move the rod vertically with respect to the outlet to increase and decrease the outlet area in response to downward and upward movement of the float whereby to reduce the flow of metal from the outlet when the level in the mold rises and to increase the flow of metal from the outlet when the level in the mold drops.

References Cited in the file of this patent UNITED STATES PATENTS 1,139,887 Mellen May 18, 1915 1,139,888 Mellen May 18, 1919' 1,893,859 Gleason et al. Jan. 10, 1933 2,290,083 Webster July 14, 1942 2,356,013 Sponner Aug. 15, 1944 2,639,490 Brennan May 26, 1953 FOREIGN PATENTS 256,026 Switzerland July 31, 1948 52,071 Netherlands Oct. 15, 1941