US3536125A - Multiple tundish system for metal refining plant - Google Patents

Description

I 2 United States Patent l 13-,5;36,1,2-5

[72] Inventors MlchelJ i I New CR8! Doylemwn, and UNITED STATES PATENTS 1 2,625,719 1/1953 Moore 164/25'8 Pawn 2,788,270 4/1957 Nisbet et al. 266/34X [211 P 7 1968 1 2,983,973 v 5/1961 'Parlanti r 164/65 {221 1 3,008,855 11/1961 SWenSOn 164/61x [451 Palm 3,460,604 8/1969 Tingquistetal. 164/61 [73] Assignee Pennwnltcurporaflon W u Zunqry grammer-JkSgencer Oxlrholser m p i szs ta nt xaminerpencer near Attorneys-Carl A. Hechmer, Jr. and Stanley Bilker A metal refining plant in which molten metal is poured from a tilting induction furnace in a first vacuum chamber into molds contained within a second vacuum [54] SYSTEM FOR METAL chamber. The two chambers are interconnected by way of a 8 D 1 horizontally operable valve disposed between the two cham- Chi, bers. A tundish which is movable in both a horizontal and a [52] US. Cl 164/258, vertical plane directs the molten metal through the valve into 164/65, 266/ l 3 a mold positioned therebelow. Means are provided to-preheat [51] Int. Cl. .l 322d 27/16 the tundish, and an auxiliary tundish is coupled to the first for [50] Field Search -l64/6l, 62, use in an emergency. All operations are controlled and visible 65. l33.254.256.258.337:266/l3,34(U) .1

from the exterior.

Patented jogt. 21, 1970 7' Sheet INVENTORS MICHAEL J. BLAS/(O gs/v r a'm'mwmwv I 14% rm/ma Patented Oct. 27, 1970 7 Sheet mnwraws MICHAEL J. ems/r0 HEW/U 0. HERRMA/V/V Pgten td Oct; 27, 19 70 Sheet v INVENTORS MICHAEL J. BLAS/(O ATTOR/VE'V MULTIPLE TUNDISH SYSTEM FOR METAL REFINING PLANT This invention relates to an apparatus and method for vacuum refining of molten metals. More particularly, it relates to a vacuum metallurgical refining plant in which there are vertically adjoining chambers interconnected through a valve. A tilting induction furnace is located in the first chamber which is connected to suitable air evacuation means. One mold at a time is positioned beneath the valve. A movable tundish which is adapted to be horizontally moved from a preheating staiton to a position over the valve can also be vertically lowered through the valve when the latter is in open position whereby the molten metal may be directed from the furnace into the molds, all under vacuum conditions. An auxiliarytundishiscoupledtothefirsttundi'shandcanbeusedduring any emergency.

Heretofore, during the vacuum refining of metals using induction furnaces, it has been the practice to melt and pour the molten metal into molds all within a single vacuum chamber. As a consequence, one could not recharge the furnace nor remove the molds without breaking the vacuum. Accordingly, the operation became inefficient since the furnace could not be used to refine a fresh charge of metal while the molds were cooling, nor could molds be moved into the vacuum chamber while the melt was being degassed in the furnace. It was therefore necessary to perform the melting and refining operation in a first chamber, pour the molten refined metal into a ladle or other suitable carrying device, and then move the ladle into a second separate and independently operated chamber in which the molten metal was teemed into molds. While mold tunnel interlocks have been employed, these not only required large door valves through which the mold cars could pass but also they consumed considerable floor space.

It is therefore an object of this invention to provide an apparatus and method for vacuum refining and pouring metal into molds simultaneously without interfering with the recharging of the furnace while the molds are cooling or the removal of the molds while a fresh batch of metal is being refined.

Another object of this invention is to provide a metallurgical refining plant in which refined molten metal can be poured through a conduit directly into molds while the entire system is under vacuum.

Still another object of this invention is to provide a vacuum metallurgical refining plant which employs a tundish system to direct molten metal from an induction fumace through an intermediate valve into molds so as to minimize floor space and enable minimal size valve components to be utilized.

Yet another object of this invention is to provide a mobile tundish system in which an auxiliary tundish is attached to the main tundish and is adapted to be immediately employed in the event of an emergency, such as failure of the main tundish.

Still yet another object of this invention is to provide a means for preheating a tundish preparatory to its use for directing molten metal into molds.

A further object of this invention is to provide a dual-chambered vacuum melting and molding plant in which an intermediate valve is used to interconnect the refining and molding chambers in combination with a mobile tundish which can be conveniently positioned at a preheating station, at an inactive station, or at a pouring station.

Yet a further object of this invention is to provide a mobile tundish system for a valved dual-chambered vacuum refining and pouring plant in which the valve sealing elements are fully protected from molten metal drippings and heat radiations.

Still yet a further object of this invention is to provide a dual-chambered vacuum metallurgical refining plant in which the pour and teeming operations are all visible and operable from a single remote external station.

Yet still another object of this invention is to provide a dualchambered vacuum metal refuting plant in which all refractory elements are conveniently exposed for maintenance.

Other objects of this invention are to provide an improved device of the character described which is easily and economically produced, which is sturdy in construction both highly efficient and efl'ective in operation.

With the above and related objects in view, this invention consists of the details of construction and combination of parts as will be more fully understood from the following detailed description when read in conjunction with. the accompanying drawings in which:

FIG. 1 is an elevational sectional view of a metallurgical refining plant embodying the instant invention. I

FIG. 2 is a sectional view taken along lines 24 of "1.

FIG. 3 is a sectional view taken along lines 3-3 of 2.

FIG. 4 is a sectional view taken along lines 4-4 of FIG. 2.

FIG. 5 is a sectional view taken along lines 5-5 ofFIG. 4.

FIG. 6 is a sectional view taken along lines 6-6 of FIG. 4.

FIG. 7 is a sectional view taken along lines 7-7 of FIG. 6.

FIG. 8 is a sectional view taken along lines 8-8 of FIG. 7.

Referring now in greater detail to the drawings in which similar reference characters refer to similar parts, we show a vacuum refining apparatus comprising a melt chamber A having a metal refining furnace B enclosed therein, a mold chamber C or tunnel for holding molds D, a valve E interposed between the two chambers, and a movable tundish assembly, generally designated as F, which is adapted to direct metal poured from the fumace B into the molds D through the valve E thereabove.

Referring especially to FIG. 1, the melt vacuum chamber A is a reinforced steel housing and includes a lower section 12, a portion of which rests upon a structural bed 14. A cover 16 is detachably secured over the lower section 12 by a suitable flanged coupling 18 and can be rolled back to expose the contents thereof. The chamber A is of sufiicient cubic dimensions to support and enclose the furnace B and is connected by a conduit 20 to an air evacuation means, such as a multistage, steamjet, high vacuum system (not shown). A suitable valved hopper 22 is mounted in the cover 16 so that the furnace B may charged under vacuum, if it is so desired. The furnace B may be any suitable high-temperature melting device for heating, melting, stirring, and refinning metal, such as steel, under high temperature conditions. Preferably, it is a careless induction furnace because of compatability with an evacuated environment and by virtue of its ability to produce stirring as well as heating by eddy current developed thereby. The furnace B includes a generally cylindrical crucible 24, of 30-ton capacity for example, which has a pouring lip or spout 26. Suitable refractory lines the entire interior of the furnace.

The furnace B is supported by means of trunnions 28 laterally extending therefrom and pivotally supported in pillow blocks 30. I-Iydraulically actuated drive means (not shown) enables the furnace to be tilted forwardly approximately for pouring molten metal into the tundish F. Means are also provided to back tilt the furnace approximately 30 from a vertical for cleaning and/0r maintenance purposes.

The mold tunnel C is also a reinforced structural steel chamber which is separated from the melt chamber A by a vertical partition wall 32 and by a horizontal deck 34. A conduit 21 couples the mold tunnel C also to the air evacuation means through suitable valving (not shown) whereby vacuum may be applied to either the mold tunnel or the chamber A independently. The valve E is incorporated in the deck 34 so that a mold assembly D may be oriented directly under the valve aperture. A platform 36 is disposed outside the melt chamber A at approximately the level of the deck 34 whereby operating personnel at a single location can conveniently observe the pour from the furnace B into the tundish F through sight port 38 and the teeming from the tundish into the-molds D via sight port 40.

The tundish amembly F is best illustrated in FIGS. 2 and 4. It includes a pair of side-by-side refractory lined channel members 42 and 44, the tundish 42 being used for normal operations and tundish 44 being an auxiliary standby or emergency unit. Each includes a generally cylindrical splash shield 46 at one end into which the molten metal is poured fiom the lip-26 of the B. A spout 48 at the other endgconveniently funnels the molten metal flow into a stream. Weir 50 interposed at the downstream side of the tundish allows the molten metal heat to be skimmed of surface contaminants.

The operating tundish.42-and the auxiliary tundish 44 are 1 both supported a pie-shaped holder or rack 52 Concave rollers 53 and 54 journaled in bearings 56 at the bottom 1 of the rack'52 engaged withand ride upon a liquid cooled arcuate pipe rail 58 which is supported on the deck 34.

The other end of the rack 52 includes an arm 60 which projects through opposed slots 62 and in cylinder member '66. The arm 60 rests on a button68 supported on the upper end of a piston 70 which is vertically reciprocable in the lower closed I end of cylinder 66. A thrust bearing 72 rotatably supports the lower end of cylinder 66, the upper portion of which includes a shaft 74 journaled in bearing 76. Rotatable motion of tundish F assembly about an definediby bearings -72and 76, is produced by rotation of pinion whichis in engagementwith bevel gear 82; onbevel gear 8 2 is jo'ur-,

naled in a sealedtbearing 86 mounted in the circumferential at the opposite endof shaft 84 outsideof the chamber A and supported below skulling platform 90 forrotating' the tundish.

F'either in a clockwise or counterclockwise direct ionas wall 12 of chamberA. .A motor drive unit its-+89 is mounted:

spout 48. Itis also to be noted that the F may beraised by elevation of piston 70 so as to stop the flow-of molten metal through the nozzle atter filling each mold. The valve E may now beclosed whereupon can be recharged under vacuum or brought up toatnrospheric conditions by rolling back the cover Skullingofthe furnace can be ac- V complished at this stage while the molds arecooling under vacuum. Conversely, while the'rnelt in the furnace is being refined under vacuum the molds can be taken out of themold r tunnel C without interfering with] operationsin the melt chamber.

is to be observed that by locating the valve E in a horizon- ,tal position vertically separating the two chambers A and C,

theteeming through the spout 48 is vertical. At the same time,

' all ofthe refractoring in both the tundish F and the fumace'B 'is fully expressed for convenient cleaning when just the cover 44 is available for immediate service.

Although this invention has been described in considerable detail such description is intended asbeing illustrative rather than limiting since the invention may be variously embodied,

l6.is rolled back. In the event of failureoftundish 42, tundish and the scope of the invention is to be determined as claimed.

7 v 25" desired. Shield 92 acts to protect the bevel andpinion from any splashing metal and/or radiant heat. The operator standing on the pouring platform 36 can observe pouring of the metal from the furnace Ainto the tundish F byway of sight port 38 or from the. tundish into the'moldsby way of sight port The isolation valve E is essentially a large horizontally actuated water-cooled gate valve which is interposed withinfan best generally illustrated in FlGS. l,2. arid 4..l'he details of construction of the valve E are best seen in FlGS. 6, 7, arid 8.

The valve E includes a housing portion which includes o pposed flanges'102and 104 for couplingto conduit fittings. in this caselflange' 102 is'bolted to'a complementaryring94 mountedwithin the deck opening. Flange 104 may have a opening in thedeck 34 between the two chambersjA and C, as l cover 'plate96 pivotally connected thereto which maybe swung out of the way when the tundish spout 48 is inserted. A

heat shield 98 is coupled to the ring .94 and tapers upwardly to r an orifice somewhat. larger than thatof the tundish spout. The

valve E'is operated by a do uble-acting hydraulic cylinder 106 whose pistonis connected to valve plate 108 through rod 110,. guiding block 112 and levers 114. Draw springs 116 connect ing. the valve plates 108 prevent the letter from slidingonthe inside of the housing. wall 100 duringhorizontalin-and-out movement. When opening, the'valve plate'is first lifted from its seat before it is moved aside. A'heat shield 118 overlies the. 'surface of the valve plate toguard it-from radiation. The

: means for moving molds into and out of said second clmmber' piston rod is sealedagainst vacuum by an oil 120;

, Suitable reinforcing ribs 121 insure the. maintenance of tundish F may thenbe swung in a horizontal plane until it situated under a canopy 122 defining a preheating stationQA series of nichrome, heat elements 124 'serve to elevate the tundish to a temperature wherein its refractory will not be appreciably shocked and so that themolten metal being poured will not sufier too great a cooling effect during pouring.

The furnace chamber-A is pumped down with the valve E closed. .Molds D are run into the mold chamber C which pumped down to thesame vacuum asthat in the chamber before the melt is poured. The valve E is opened the tundish F rotated until in'approximate registration with the furnace. The tundish spout 48 is=next loweredthrough thevalveEr r r From a position outside the chambersA and C, the operator on platform 36 tilts the-furnace B forwardlywhile observing the pour through sight 'port'38. Teerning. from the tundish into, V the mold D is visiblerthroughl sightport 40..When all of the I molrk have been is elevatedto 55. p r As is apparent from the foregoing description, the tundish F molten metal is poured therethrough. 1

" 3. The apparatus of claim 1 wherein said conduit means comprises a first tundish for performing the pouring operations and a second tundish coupled thereto for standby emer- We claim: i l. Metallurgical. refining apparatus comprising a first chamber including fumace means for meltingand refining metal therein, a second chamber'including a horizontal portion extending at least partially within said first chamber, valve means interposed within said horizontal portion for isolating said first and second chambers fromeach other, means for opening and closing said valve means, means for'evacuating r said first and second chambers, conduit means including an inlet end for receiving molten metal from said fumace means, an intermediate channel portion for directing the-molten metalalong a substantially horizontal path, and a discharge end for vertically teeming the molten metal into a mold located'therebelow, vcarriagev means supporting said conduit 1 means in said first chamber, first drive means for horizontally orienting said carriage means at a pouring position in which the inletof conduit means is in registration with metal being poured from said furnace and said discharge end is in registration with said valve means-, second drive means for vertically displacing the discharge end of said conduitmeans from an elevated position over'said valve to a lowered position extending through said valve r when open, and

andaligning one mold ata time under the discharge end of said conduit means, whereby said first and secondchambers berindependently and interdependently operated under ,vacuumconditions'. j. 2. The apparatusof claim 1 including a heating station 1 means in said first chamber horizontally displaced from said pouring position. for preheating said conduit means before gency operations in the event of failure at 'said first tundish.

4. The apparatus of claim 1 wherein said carriage means is pivotally supported about vertical and horizontal axes. r

5; The apparatus of claim 4 wherein said carriage means includes an arcuate rail disposedin a horizontal plane, and

means constituting rollers engaging said rail.

I v 6.,The apparatusofclaim 5 wherein said roller means de- 65;

Z stituting a rotatable cylinder embracing the other end of said carriagemeans. P

1 7. apparatus of claim 6 including a piston in said rotatable cylinder engaging said other end of said carriage means.

' 8. The apparatus or claim 1 w rein said valve meam con- .pend from one end of said carriage means, and means constitutes a gate valve.

9The apparatus of claim 11 in which of said means are j operable from a position extemal-to said'chambers.

10. The apparatus of claim 9 including means to view the pouring and teeming operation from a single station external to said chambers.

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