US 3460725 A
Description (OCR text may contain errors)
United States Patent Office 3,460,725 Patented Aug. 12, 1969 3,460,725 APPARATUS FOR POURING MOLTEN METAL Karl-Heinz Golde, Ratingen, and Horst Buschmann,
Solingen-Ohligs, Germany, assignors to Schloemann Aktiengesellschaft, Dusseldorf, Germany a company of Germany Filed May 2, 1968, Ser. No. 726,161 Int. Cl. B65d 5/72, 25/40,- B22d 41/00 U.S. Cl. 222567 Claims ABSTRACT OF THE DISCLOSURE Apparatus for use in pouring molten metal from a first vessel to a second vessel below through an outlet in the bottom of the first vessel consists of a tube of refractory material having a larger diameter than the outlet. The tube is in two parts, one resting on the other with a tubular jacket encircling contiguous portions of both parts, both parts being supported in the jacket. Thus, either part is replaceable. The jacket is larger than the tube to provide space for inserting refractory material between them. A lever pivotally connected to the jacket is adapted to raise the jacket and tube to, and lower it from, a position in which the upper end of the tube is against the bottom of the first vessel, around the outlet. The lever is adapted to press the tube resiliently against the bottom of the first vessel, and the tube is made sufficiently long for its bottom end to extend below the surface of molten metal contained in the second vessel.
This invention is apparatus for pouring molten metal, and particularly for pouring molten metal from a ladle into a tundish from which the metal is poured into a continuous-casting mold.
A stream of metal from a ladle has a rather turbulent surface at which air may react with the metal and through which deleterious gases may infiltrate the melt in the ladle, as well as the metal in the stream. Also, air coming in contact with the stream of metal cools it. Moreover, when the stream is exposed, splashing of the stream can cause damage or injury.
Gas absorption by the stream may be avoided by using vacuum-casting techniques, which also degas the melt, but these techniques increase the turbulence of the stream and thus increase the risk of injury from splashes, as well as increasing the encrustation of splashed metal on adjacent surfaces.
An object of this invention is to provide a pouring apparatus which largely prevents gas absorption and reactions with air by a stream of poured metal.
Another object is to prevent undesired cooling and to eliminate the danger of injury or damage due to splashing of the stream.
The foregoing and additional objects are accomplished by the apparatus of this invention, in which a tube of refractory material is adapted to encircle a stream of molten metal being poured from the outlet in the bottom of a ladle into a tundish below the ladle. The ladle is provided with a conventional stopper for opening and closing the outlet. The tube is a larger diameter than the outlet, so that the surface of the stream does not come in contact with the inside of the tube.
The tube is mounted to be raised to and lowered from a position in which its upper end is against the bottom of the ladle around the outlet. A ring may be attached to the ladle bottom around the outlet to provide the ladle surface engaged by the upper end of the tube, and in the following description the bottom of-the ladle against which the tube comes in contact may be the bottom surface of the aforesaid ring.
The tube is made long enough so that when its upper end is against the ladle bottom, its lower end may extend down and open below the surface of molten metal contained in the tundish, but extends down only far enough to provide clearance for the tube to be lowered further into the tundish without hitting bottom.
The tube thus shields the stream from the surrounding air which ordinarily cools the stream to an undesirable extent and which may react with the metal. The tube also eliminates the risk of injury or damage from splashing. In addition the tube prevents gases in the surrounding air from coming in contact with the stream and contaminating the metal, and in one embodiment means is provided for introducing a protective gas under pressure in the tube to further protect the stream from reactions with air or contamination by gases in the air.
In a preferred embodiment the tube is in two parts, one above the other, which enables a worn part to be replaced without having to replace the Whole tube and which reduces the vertical clearance required for replacing the.tube, or one of its parts. A tubular jacket is supported around the outside of the tube and extends around the junction between the parts; the diameter of the jacket is sufiiciently larger than the diameter of the tube to provide a space between, in which to inject a castable refractory to further increase the shielding effect of the tube.
Since, in accordance with the invention, the tube is adapted to be raised and lowered the ladle may be kept at one level and may be swung laterally into and out of pouring position over the tundish; when the ladle is in pouring position, the tube is raised to its position against the bottom of the ladle around the outlet. When the empty ladle is to be removed, the tube is lowered into the tundish to free the ladle to be moved away in a horizontal path.
In a preferred form the upper end surface of the tube is grooved to receive a gasket material, such as asbestos cord or refractory mortar, for tightly sealing the joint between the tube and the bottom of the ladle when the tube is raised into position against the ladle bottom.
The means for raising and lowering the tube includes a spring device adapted to press the tube resiliently against the bottom of the ladle when the tube is raised to engage the ladle bottom. This assures a right joint and provides for thermal expansion.
This apparatus is particularly adapted for use with continuous-casting apparatus in which the tundish has an outlet nozzle adapted to extend below the level of molten metal in the mold, and in which the tundish is therefore raised and lowered to position it for a casting run. In this situation the tube will be retained in its upward position against the bottom of the ladle when the tundish is lowered and removed; as mentioned above, the length of the tube is such that it extends below the surface of metal in the tundish but is far enough above the bottom of the tundish to permit relative vertical movement of the tube and tundish When it is desired to remove the ladle, the tube is then lowered into the tundish as noted above.
The invention will now be described. in detail with reference to the accompanying drawings in which:
FIG. 1 is a cross section through an illustrative embodiment of apparatus in accordance with the invention, taken through the axis of the pouring tube; and
FIG. 2 is a side view, partly broken away, of a springloaded jack which forms part of the mechanism for raising and lowering the tube, the view being at right angles from the view of the jack shown in FIG. 1.
Referring to the drawings, a ladle 10 having a bottom 11 has a refractory lining 12 and an outlet 13 defined by a nozzle 13a, supported through an appropriate opening in the bottom 11. The upper end of the nozzle 13a, which is particularly exposed to wear, is provided with a replaceable annular insert 14-. The outlet 13 is suitably opened and closed by a conventional stopper (not shown).
A steel ring 15 is attached on the ladle bottom 11 around the outlet 13, and the nozzle 13a extends down into the ring, the nozzle being centered in the opening through the ladle bottom and in the ring 15 by an annular brick 16 around the nozzle.
For a casting operation the ladle is positioned for a stream of metal to pour from its outlet 13 down into a tundish 17 below. The metal is then poured from the tundish into a mold (not shown) through an outlet (not shown) in the tundish.
In accordance with the present invention the stream of molten metal from the ladle 10 to the tundish 17 is encircled by a tube 18 of refractory material. The tube 18 is a larger diameter than the outlet 13 so that the stream will not come in contact with the interior walls of the tube. The upper end of the tube 18 is flared outward, like a funnel, and is adapted to coincide with and press against the lower face of the ring 15, which is machined to form a smooth contacting surface. The upper end edge of the tube is provided with an annular groove 19 in which refractory packing 20 is placed to provide a tight seal.
The tundish 17 is provided with a cover 21 which has an opening 22 for the tube 18 to extend down through. As shown, the tube 18 is made long enough so that, with its upper end against the ring at the bottom of the ladle 10, its lower end will be below the surface of molten metal 23 contained in the tundish 17, but leaving clearance between the lower end of the tube 18 and the bottom of the tundish to enable the tube 18 to be lowered further into the tundish in order to lower the upper end of the tube down out of contact with the ring 15. By thus being able to lower the tube 18, the ladle 10 may be moved in a horizontal path when it is removed from its pouring position over the tundish.
The tube 18 is in two parts, a lower part 18a and an upper part 18b supported on the lower part at a joint 24 so that either part may be replaced without having to replace the entire tube 18.
A tubular metal jacket 24 is around the tube 18, including the portion of the tube at which its two parts 18a and 18b are joined at joint 25, and the inside diameter of the jacket 24 is enough larger than the outside diameter of the tube 18 to leave an annular space 26 between into which refractory material 27, such as granular fireclay or sand, is placed.
The lower end of the jacket 24 has an inwardly pro-i jecting flange 28 on which rests an outwardly projecting flange 29, around the lower tube part 18a for supporting the tube parts 18a and 18b in the jacket 24, and for centering the tube within the jacket.
The jacket 24, and hence the tube 18, are mounted to be raised to, and lowered from, a position in which the upper end of the tube 18 is pressed against the lower face of the ring 15 on the bottom of the ladle. For this purpose the jacket 24 and tube 18 are supported in a gimbal ring 30, which encircles the jacket, by trunnions 31 on the jacket. The ring 30 is in turn pivotably supported between forks 32 at one end of a lever 33 by studs 34 projecting from the opposite sides of the ring 30 and received in longitudinal slots 35 in the ends of the forks 32. The lever 33 is supported by a pivot 36 and is raised and lowered to raise and lower the jacket 24 and tube 18 by a jack mechanism 37 at the other end of the lever. In FIG. 1 the raised position of the lever 33 is shown in full lines; a lower position is shown in dash lines.
The jack mechanism 37 consists of a housing 38 pivotally supported at 39 between a pair of spaced brackets 40. A shaft 41 is movable up and down from out of the housing 38 by a hand wheel 50 which operates conventional means (not shown) for raising and lowering the shaft 41 relative to the housing 38. A cap 42 fixed on the upper end of the shaft 41 has 21 depending skirt with an inwardly turned lower edge 43. A cylindrical element 44 having an axial bore is slidable on the shaft 41. The upper end of the cylindrical element 44 is within the cap 42 and has an outwardly projecting flange 45 with a coil spring 46 around the cylindrical element between its flange 45 and the top of the cap. The lower end of the cylindrical element 44 extends down out of the lower end of the cap 42 and has a stud 47 projecting out to the side and engaged by an upwardly facing hook 48 on the outer end of the lever 33. Thus, when the jack mechanism is operated to pull the outer end of the lever 33 down for raising the tube 18 to the position in which the upper end of the tube is pressed against the ring 15 on the bottom of the ladle 10, the spring 46 is compressed and thereby causes the tube to be pressed against the ring 15 with a resilient pressure to make a tight seal and to provide for thermal expansion.
The tube 18 thus shields the stream of molten metal from the ladle 10 to the tundish 17 to protect the stream from the cooling and reactive effect of the surrounding air and from contamination of the metal by gases in the air. This protection of the stream may be increased by injecting a protective gas into the space between the stream and the inside of the tube 18 and maintaining the protective gas under a slight pressure. For this purpose the ring 15 may be provided with an aperture 49 through which a protective gas may be injected, there being sufiicient space between the inside of the ring 15 and the brick 16 for the gas to flow down into the interior of the tube 18.
What is claimed is:
1. Apparatus for use in pouring molten metal from a first vessel into a second vessel below, said vessel having an outlet for molten metal through the bottom with a substantially flat surface on the underside of the bottom around the outlet, said apparatus comprising a tube of refractory material having a larger diameter than said outlet and an upper end surface adapted to bear against said flat surface 'of the first vessel around said outlet means for supporting the tube in position with its said upper end surface against said flat surface, said tube being of sufficient length for its lower end to extend below the surface of molten metal contained in the second vessel when its upper end is against said flat surface.
2. The apparatus of claim 1 in which said means for supporting the tube in said position includes means for resiliently urging the tube against said flat surface when the tube is in said position.
3. The apparatus of claim 1 in which said fiat surface around said outlet is provided by the lower surface of a ring attached to the bottom of the first vessel and in which said ring has an orifice through its side for introducing a protective gas to fill the space between the interior of the tube against said flat surface and a stream of molten metal passing through the tube.
4. The apparatus of claim 1 which includes a tubular jacket encircling a portion of the length of the tube, the inside diameter of the jacket being larger than the outside diameter of the tube for providing a space in which to insert a refractory material between the tube and jacket, and means for supporting the tube within the jacket.
5. The apparatus of claim 4 in which said means for supporting the tube within the jacket comprises an outwardly projecting shoulder on the outside of the tube supported on an inwardly projecting flange on the inside of the jacket.
6. The apparatus of claim 1 including means for raising the tube to and lowering it from said position.
7. The apparatus of claim 5 in which said upper end surface of the tube has a continuous groove therein for supporting packing material to make a continuous joint with said flat surface around said outlet when the tube is in said position.
8. The pouring apparatus of claim 6 in which said raising and lowering means comprises a lever, a gimbal ring mounting the jacket on an end portion of the lever, said lever being pivotally mounted for raising and lowering said end portion and means for engaging and pivoting the lever to raise and lower said end portion, said latter means making resilient contact with the lever whereby said upper end surface of the tube is resiliently urged against said flat surface of the first vessel when the said end portion of the lever is in raised position.
9. The apparatus of claim 1 in which said tube comprises an upper tubular part resting on a coaxial lower tubular part, said means for supporting the tube being arranged to support the lower part and thereby support the upper part also, said apparatus including a tubular jacket encircling contiguous portions of the upper and lower parts, the inside diameter of the jacket being larger than the outside diameter of the tube for providing a space in which to insert a refractory material between the tube and jacket, means for supporting the tube within the jacket, and means for raising the tube to, and lowering from, said position.
10. The apparatus of claim 9, in which said raising References Cited UNITED STATES PATENTS 1,923,119 8/1933 Seidel 222-567 FOREIGN PATENTS 810,653 3/1959 Great Britain.
ROBERT B. REEVES, Primary Examiner H. S. LANE, Assistant Examiner U.S. Cl. X.R. 164-335