US3645322A - Feed device for continuous casting machines for the production of a continuous metallic ingot - Google Patents

Abstract

A feeding device for continuous casting apparatus arranged to pour molten metal into a peripheral groove of a casting wheel in order to obtain a continuous rod, and provided with a crucible which may oscillate around a substantially horizontal axis the latter being coincident with the axis of an outlet nozzle for the molten metal.

Description

United States Patent Properzi 1 Feb. 29, 1972 [54] FEED DEVICE FOR CONTINUOUS CASTING MACHINES FOR THE PRODUCTION OF A CONTINUOUS METALLIC INGOT [72] Inventor: Ilario Properzi, Via Vittor Pisani 8,

Milan, Italy 221 Filed: $553951,

21 Appl. No.: 15,748

[30] Foreign Application Priority Data Dec. 19,1969 Italy ..26078A/69' Jan. 20, 1970 Italy ..19584A/70 I [52] U.S. Cl ..l64/28l, 164/87 [51] Int. Cl ..B22d 11/10 [58] Field of Search ..164/66, 87, 136, 259, 278, 164/281 [56] Relerences Cited UNITED STATES PATENTS 2,659,949 1 H1953 Properzi 1 64/278 3,331,431 7/1967 Bray et al ..l64/278 X FOREIGN PATENTS OR APPLICATIONS 1,008,478 2/1952 France ..l64/281 1,041,549 9/1966 Great Britain ..164/278 Primary Examiner-4i. Spencer Annear Attorney-Guido Modiano and Albert .losif 571 ABSTRACT A feeding device for continuous casting apparatus arranged to pour molten metal into a peripheral groove of a casting wheel in order to obtain a continuous rod, and provided with a crucible which may oscillate around a substantially horizontal axis the latter being coincident with the axis of an outlet nozzle for the molten metal. I,

3 Claims, 14 Drawing Figures PATENTEDFEB29 I972 3. 645.322

sum 1 or 7 INVENTOR.

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' lLARlO PROPERZI PATENTEUFEB29 I972 3. 645,322

sum 5 OF 7 INVENTOR.

ILARIO PROPERZI AGENT v PATENTEDFEBZS I972 SHEET 7 0F 7 INVENTOR.

I LARIO PROPERZI A G E NT FEED DEVICE FOR CONTINUOUS CASTING MACHINES FOR THE PRODUCTION OF A CONTINUOUS METALLIC INGOT BACKGROUND OF THE INVENTION The present invention relates to a feed device for continuous casting machines for the production of a continuous metallic rod.

A continuous casting machine of the rotating grooved wheel type for producing continuous metallic bars or rods consists essentially of a rotating wheel provided with a groove on its peripheral surface having the shape of the rod section which is to be obtained, this groove being covered through a certain are by a metallic tape or belt which closes a portion of the groove and moves together with said wheel, so that the liquid metal which enters the groove at the beginning of the covered portion is held therein and leaves it in the shape of a solid continuous bar at the end of that portion.

The pouring of the liquid metal into the covered portion is accomplished by meansof a crucible provided with a needle flow control and an outlet nozzle or channel which conveys the liquid metal into the portion of wheel groove covered by the tape.

However with this conventional pouring system there are various disadvantages, among which is that of a certain difficulty in controlling the metal flow, because said needle control is frequently subject to partial blockage and wear which may be considerable in a short length of time, with consequent irregularity in the flow of molten metal.

A further disadvantage of the conventional pouring system is the wear or blockage which the flow noule of said crucible is subject to, because of which the life of said nozzle is reduced in general to a few hours, thus rendering frequent replacement operations necessary (it should be noted that the nozzle has a pointed shape in order to be able to penetrate the groove of the casting wheel).

The main object of the present invention is that of substantially eliminating the disadvantages stated above relative to conventional pouring systems, by providing a feed or pouring device for continuous casting machines which allows reliable and easy flow adjustment, and allows the use of a nozzle of large external diameter because of which the metal is automatically protected from oxidation because of the large thickness of the walls where these are of refractory materials which are in a greater or less extent always porous.

A further object of the invention is that of providing a particular container which allows filling, emptying and adjustment while operating of the liquid head, so as to determine a velocity of flow of liquid from the outlet hole according to the well-known formula V= J 2 gh.

SUMMARY OF THE INVENTION These and still further objects are attained by the feed device for continuous casting machines according to the invention, comprising a crucible rotably mounted about 3 preferably substantially horizontal axis, and comprising an internal cavity at least partly eccentric with respect to said axis for the formation of a liquid head which varies on varying the angular position of said crucible, a lateral outlet nozzle communicating with said cavity being connected to said crucible for the introduction of molten metal into the-groove of the casting wheel.

BRIEF DESCRIPTION OF THE DRAWINGS Further characteristics and advantages of the invention will better appear from the detailed description of a preferred embodiment of the feed device for continuous casting machines according to the invention, illustrated by way of example in the accompanying drawings in which:

FIG. I is a front view of the feed device according to the invention applied to a continuous casting machine;

FIGS. 2 and 3 are a front view on an enlarged scale of the device shown in FIG. 1, in the waiting and operational positions, respectively;

FIG. 4 is a partially sectional side view of said device;

FIGS. 5, 6, 7 are transversal sectional views of the device according to the invention, in three different positions, respectively;

FIG. 8 is a perspective view of the device according to the invention;

FIGS. 9 and I0 show the device according to the invention applied to the summit of the casting wheel, in the waiting and operational positions, respectively;

FIG. 11 is a longitudinal sectional view of one variation of the feed device;

FIG. 12 is a sectional view of a part of the device shown in FIG. 11, in a modified embodiment;

FIG. 13 is a frontal partially sectional view of the device shown in FIG. 11; and

FIG. 14 is a transveral sectional view through the casting nozzle of the device shown in FIG. 1 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. l-l0, the feed device according to the invention comprises a crucible I mounted to oscillate about a substantially horizontal axis parallel to the axis of the casting wheel 2. Only the grooved peripheral edge of the casting wheel is shown and the conventional means for the internal and external cooling of said wheel are also omitted. A metallic tape 3 is wound on this wheel for more than one-half of its circumference, and is driven conventionally by means of driving rollers 4 and 4a which thus define a receiving zone 5 for the molten metal and an outlet zone 6 for the rod produced by the machine, respectively.

The crucible 1 comprises a cylindrical container having a transversal section of circular shape and an internal cavity substantially in the form of a sector, said container being internally provided with a lining 7 of suitable refractory material.

This lining is arranged so as to shape said internal cavity with a recessed portion in the form of a tray 8 which is eccentric with respect to the axis of oscillation of the crucible I. Said recessed portion or receptacle 8 can receive a certain quantity of molten metal which is to be introduced into the groove of the casting wheel 2.

The crucible l is supported by two brackets 9 with U sections, rigid with a slide 10 which vertically slides on a support stanchion 11 which, in its turn, is connected to the supporting structure of the casting machine.

In particular, the stanchion 11 supports a motor unit 12 for vertically moving the slide 10 and may in its turn be horizontally movable in two orthogonal directions parallel to the axis of rotation of the wheel 2 and at to said axis, respectively. For this purpose the stanchion ll slides on horizontal guides 13 supported by a slide 14 which slides on other horizontal guides 15 rigid with the fixed structure 1511.

A motor unit 14a is provided for sliding the slide 14 on the guides 15, and another motor unit (not visible) is provided for sliding the stanchion l 1 along the guides 13.

In the throats of the brackets 9 are housed rotatable rolling members such as rollers 16, two for each bracket, on which rest two platelike arcuate ribs 17, rigid with the crucible 1 and having an edge which coincides with a part of the circumference and defines a peripheral guiding surface.

Said ribs 17 partially penetrate into the cavity of the brackets 9 and define the axis geometric of rotation of the crucible l at the centers of the circumferences which inscribe .the corresponding profiles. Said axis geometric is parallel to but spaced from the axis of the cylindrical container which comprises said crucible, or crucible axis.

The nozzle 18, fixed to the front of the crucible 1 (said nozzle having a particular structure which will be further described hereinafter), is disposed in such a manner that its horizontal hole 18a, communicating with the internal cavity of said crucible, has an axis which coincides with said geometric axis of rotation (determined by the arcuate ribs 17).

The crucible 1 is provided laterally with a toothed sector 19 for the provision of the oscillating movement, the axis of which coincides with the axis of rotation. This sector 19 engages with a pinion gear 20 connected to corresponding motor means 20a. When this latter is operated, the crucible 1 can be made to rotate through a certain angle in one direction or the other.

The nozzle 18, of suitable material, for example graphite or carborundum, consists of first substantially cylindrical body (FIG. 4) in which said longitudinal hole 180 (in communication with the crucible cavity) is provided and a second body having a second hole 18b communicating with the first and orthogonal to it. As shown in the drawings the hole 18b has a smaller section than the hole 184. The first body of the nozzle 18 is disposed horizontally and the second body may be shaped so as to penetrate into the groove of the wheel 2. This shaping however may be omitted. Further the nozzle 18 is arranged close to the roller 4, where the tape 3 leaves the wheel 2.

To permit introduction of molten metal into the crucible 1 for any angular position which it may assume, a recessed arcuated portion or slot 21 is provided on the backwall opposite the nozzle 18 and the mouth of an inclined channel 22 is inserted into it, and conveys the molten metal from a waiting feed furnace (not shown).

The open upper part of the crucible 1 can be connected to an arched cover 23, hinged at 24 to the wall portion 25 of the internal cavity. Said cover also covers the recessed portion 21 when it is closed.

The crucible 1 can be rotated into the emptying position as shown by the dotted lines in FIG. 5. For permitting its movement into this position, the channel 22 has its end section hinged so that it may be turned upwards so disconnecting it from the recessed portion 21.

If the molten metal has to be poured at the summit position of the wheel 2, the crucible l is arranged substantially as indicated in FIGS. 9 and 10 so that casting can be more or less horizontal. In this case the casting machine will have an arrangement of driving rollers 4 and 4a which is rotated with respect to the arrangement shown in FIG. 1 so that the casting zone 5 is formed close to the summit of the wheel 2.

In this case the nozzle 18 is also fixed to the crucible l in a position which is rotated with respect to the above so that the outlet hole 18b becomes arranged in an approximately horizontal direction during the casting phase (FIG.

The operation of the feed device according to the invention is as follows.

The molten metal collects in the recessed portion 8 in the crucible l, where it will have a certain head with respect to the hole 18a, depending on the angular position of the crucible.

More precisely, in the rest position shown in FIG. 5 (which corresponds to the arrangements in FIG. 2 and 9) the level of the molten metal in the recessed portion will be less than the level of the hole 18a of the nozzle 18 and hence there will be no exit of metal through this latter.

On rotating the crucible through a certain angle in the anticlockwise direction, with reference to FIGS. 5, 6 and 7, a movement in level of the molten metal will be obtained until it passes beyond the -hole 18a. For example, in the position shown in FIG. 6 a certain head H is formed and there will be a certain flow through the nozzle 18 which is proportional to this head.

If the rotation of the crucible l in the anticlockwise direction is increased, there will be an increase in head. For example in the arrangements shown in FIG. 7 (corresponding to the positions shown in FIGS. 3 and 10) a head I-Il will be obtained greater than the head H with a consequent increase in flow of the molten metal leaving through the nozzle 18.

In the position shown in FIG. 5, by raising the cover 23 it is possible for the operator to directly observe the level of mo]- ten metal in the crucible. In this manner a direct check is possible before casting into the wheel.

Consequently by rotating the crucible from the position shown 'in FIG; 5 it is possible to gradually increase the flow of molten metal through the nozzle 18, from zero to a determined maximum value, proportional to. 112 g H where H is the value of the head in the crucible l.

Rotation of the crucible takes place by means of the motor mechanism 20a, for example by pushbutton control.

The particular structure of the nozzle 18 makes continuous operation for long periods possible in that the nozzle is able to support very well the elevated temperatures during the passage of molten metal. In fact the external dimensions of the nozzle can be relatively large so as to obtain good resistance both mechanically and to heat (it should be remembered that nozzles of conventional type are arranged vertically and are very pointed at their end for insertion into the groove of the wheel, so that they are less able to support elevated temperatures).

On further rotation of the crucible I, turning the channel 22 upwards and raising the cover 23, it is possible to obtain discharge of the molten metal contained in it through the opening, when in the dotted position shown in FIG. 5.

It can be seen that with the device according to the invention, flow adjustment takes place without intervention of valve adjustment means such as those used in conventional devices, the result being a constructional simplification of great advantage from the point of view of regularity of flow of molten metal, in addition to its durability.

In the variations shown in FIGS. ll, 13 and 14, while the structure of the crucible I described above is maintained substantially unchanged, a particular seal arrangement is provided with introduction of a protective atmosphere both into the cavity of the crucible 1 and around the nonle 26.

More precisely the nozzle 26, fixed at the front of the crucible 1, comprises a cylindrical body 26a (FIG. 11) disposed with its axis horizontal and enlarging into a truncated conical section 26b in the fixing zone. As in the foregoing description, the nozzle 26 is also provided of suitable material, for example, graphite or carborundum, and comprises a longitudinal hole 26c (in communication with the cavity of the crucible) and a second hole 26b communicating with the first and orthogonal to it.

A caplike sheath 27 (FIG. 11) of substantially cylindrical form is mounted on the nozzle 26 and has a diameter slightly greater than that of said nozzle. More precisely said sheath 27 is composed of an internal part of steel 27a and a lining 27b of thermally insulating material.

The sheath 27 is fixed to the front or the crucible l by means of a flange 28 with a seal ring 29 of suitable material between them, for example, asbestos or the like. The sheath 27 is provided with a hole 27c in a position corresponding with the hole 26d of the nozzle 26.

Between the sheath 27 and the nozzle 26 an interspace 30 is formed which is connected to the crucible I through a passage 31a formed in the sleeve 31 of refractory material which sur' rounds the portion 26b of said nozzle, and by way of a further passage 32a formed in the refractory 32 which lines the internal surface of the crucible 1 (FIG. 1 l). The passage 32a opens into the crucible 1 above the maximum level of the molten metal.

The upper open part of the crucible l issimilarly provided as described above with an arched cover 33 provided internally with a lining 32 of thermally insulating material and connected to a burner 34 which is inclined so as to direct the flame towards the nozzle 26. Said burner 34 can be of the type suitable for forming an oxy-acetylene flame and is provided with an adjustment knob 34a by means of which the quantity of fuel can be varied. Obviously the burner may be of any other type, for example, for methane, but always provided with a knob 34a for adjusting the quantity of fuel. I

The cover 33 is further provided with a gasket 33a of thermally insulating material, arranged so as to seal it when the' cover 33, hinged at 35, is closed as shown in FIG. 13. For the introduction of the molten metal into the crucible 1 when in any of its angular positions, an arched opening 13 is provided on the bottom wall opposite the nozzle 26, into which the end portion of an inclined channel 37 is inserted, which conveys the molten metal from a waiting feed furnace (not shown).

A plate 38 is fixed to the channel 37 and is of arched shape in the form of an arc of a circle greater than that of the opening 37, and adheres to the bottom of the crucible l by way of a gasket 38a of thermally insulating material. The plate 38 also rests on the side of the cover 33 so that when it is closed, the opening 36 is hermetically closed and the internal cavity of the crucible 1 is hermetically isolated with respect to atmosphere.

The operation of the feed device illustrated in FIGS. 11, 13 and 14 is as follows.

By adjusting the knob 34a of the burner 34 so as to reduce the quantity of oxygen fed to the burner, a reducing flame is formed so that inside the crucible a protective atmosphere is created which is very advantageous for perfect protection of the molten metal. The protective gases in addition to acting inside the crucible 1, also act on the nozzle 26. In fact these gases pass through the passages 32a and 31a and enter the interspace 30 between the sheath 27 and the nozzle 26. In this manner the cylindrical section 26a of the nozzle 26 is completely surrounded by a protective atmosphere which impedes oxidation of the nozzle 26, so considerably prolonging its life. The protective gases from the burner 34 leave the sheath 27 through the hole 27c and, during casting, surround the casting jet (FIG. 14) so protecting it from oxidation as far as the groove of the wheel 2. In this manner the molten metal can be protected against oxidation both during the preparation phase, when the molten metal is in the stationary position in the crucible 1, and during casting, when the molten metal is introduced into the casting wheel passing through the holes 26c and 26d of the nozzle 26.

For adjusting the liquid head in the crucible 1 and hence the flow of molten metal during casting, the crucible 1 is partially rotated around its own axis of rotation, coinciding with the axis of the nozzle 26, as in the foregoing description.

In the modified embodiment of FIG. 12, a second burner 39 is provided, adjusted so as to produce a reducing flame, fixed to the projecting part of the sheath 27 which is provided with a corresponding hole 27b and shaped as a trunk of a cone. The extremity of the nozzle 26 also has a corresponding truncated conical portion 26c. The burner 39 serves for efficiently heating the nozzle 26 so as to avoid it expanding during the initial casting phase. In this case the protective combustion gases also surround the nozzle 26 so prolonging its life.

The burner 39 can be utilized continually or intermittently. In this latter case, when the burner 39 is not operating, it is removed and the hole 27d is plugged. Obviously the burner 39 can operate together with the burner 34, or said burners can operate alternately.

When only the burner 39 operates, the reducing combustion gases from it, in addition to surrounding the nozzle 26, also penetrate the cavity of the crucible 1 through the passages 31a and 32a.

As can be seen, the feed or pouring device shown in FIGS. 11-14, ensures a practically total protection, including both the inside of the crucible 1 and the nozzle 26, and the corresponding casting jet. Such a device is particularly suitable for casting copper.

The invention so conceived may be modified without departing from the scope of the inventive concept.

For example the crucible may have a different cross section to that shown and may rotate about an axis inclined to the horizontal.

1 claim:

1. In a machine for the continuous casting of molten metal having a rotatable casting wheel with a peripheral groove therein and a metal belt encircling said wheel over an arc of the periphery thereof to define with said groove a casting mould, a feed device for the molten metal comprising a crucible for the molten metal having an elongated form extending around a crucible axis thereof substantially parallel to the axis of rotation of said casting wheel and a front wall substantially orthogonal to said axis, nozzle means for discharging the molten metal arranged on said front wall, supporting means for said crucible for displacing said crucible according directions parallel to the axis of rotation of the castin wheel and perpendicular thereto in a vertical and horizon plane, wherein, ac-

cording to the improvement, said supporting means further comprises at least one pair of spaced rolling members ar ranged spaced-apart and parallel to each other, at least two support members for said crucible and having each a peripheral substantially semicircular guiding surface for engaging said rolling members, said substantially semicircular peripheral guiding surfaces having a geometric center of semicircular arc thereof lying on a geometric axis passing through said nozzle means and parallel to said crucible axis and wherein said crucible has a substantially cylindrical form extending along said crucible axis and a shaped lateral inner wall defining an inner receptacle space eccentrically arranged with respect to said geometric axis passing through said nozzle means and having a cross-sectional contour whereof the distance from the said geometric axis varies progressively, thus causing the molten metal to assume a variable level inside said crucible with respect to said nozzle means when said support members are caused to move together with said crucible on said rolling members and said crucible is thereby rotated around said geometric axis passing through said nozzle means.

2. A device as claimed in claim 1, wherein said crucible has a backwall opposite to said frontal wall arranged orthogonally to said crucible axis and with a substantially arcuated slot in the upper portion thereof, and wherein said device further comprises a fixed feeding channel penetrating into said slot for the feeding of molten metal to said crucible even when said crucible is caused to oscillate around said geometric axis from a first position to a second position angularly spaced from the first position.

3. A device as claimed in claim 1, wherein said nozzle means comprise a first body portion extending from said front wall parallel to said geometric axis and having a first substantially cylindrical hole thereinside substantially parallel to said geometric axis, and a second body portion extending orthogonally from said first body portion and having a second hole thereinside communicating with said first hole and opening outside thereof, said second hole having a cross-sectional area smaller than that of said first hole.

Claims (3)

1. In a machine for the continuous casting of molten metal having a rotatable casting wheel with a peripheral groove therein and a metal belt encircling said wheel over an arc of the periphery thereof to define with said groove a casting mould, a feed device for the molten metal comprising a crucible for the molten metal having an elongated form extending around a crucible axis thereof substantially parallel to the axis of rotation of said casting wheel and a front wall substantially orthogonal to said axis, nozzle means for discharging the molten metal arranged on said front wall, supporting means for said crucible for displacing said crucible according directions parallel to the axis of rotation of the casting wheel and perpendicular thereto in a vertical and horizontal plane, wherein, according to the improvement, said supporting means further comprises at least one pair of spaced rolling members arranged spaced-apart and parallel to each other, at least two support members for said crucible and having each a peripheral substantially semicircular guiding surface for engaging said rolling members, said substantially semicircular peripheral guiding surfaces having a geometric center of semicircular arc thereof lying on a geometric axis passing through said nozzle means and parallel to said crucible axis and wherein said crucible has a substantially cylindrical form extending along said crucible axis and a shaped lateral inner wall defining an inner receptacle space eccentrically arranged with respect to said geometric axis passing through said nozzle means and having a cross-sectional contour whereof the distance from the said geometric axis varies progressively, thus causing the molten metal to assume a variable level inside said crucible with respect to said nozzle means when said support members are caused to move together with said crucible on said rolling members and said crucible is thereby rotated around said geometric axis passing through said nozzle means.

2. A device as claimed in claim 1, wherein said crucible has a backwall opposite to said frontal wall arranged orthogonally to said crucible axis and with a substantially arcuated slot in the upper portion thereof, and wherein said device further comprises a fixed feeding channel penetrating into said slot for the feeding of molten metal to said crucible even when said crucible is caused to oscillate around said geometric axis from a first position to a second position angularly spaced from the first position.

3. A device as claimed in claim 1, wherein said nozzle means comprise a first body portion extending from said front wall parallel to said geometric axis and having a first substantially cylindrical hole thereinside substantially parallel to said geometric axis, and a second body portion extending orthogonally from said first body portion and having a second hole thereinside communicating with said first hole and opening outside thereof, said second hole having a cross-sectional area smaller than that of said first hole.

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