US2039738A - Metallurgical furnace - Google Patents

Description

May 5, 1936. J. D. PUGH 2,039,738

METALL RGICAL FURNACE Filed May 5, 1935 4 Sheets-Sheet 1 1/5 L E/- Z- gmwawly/ May 5, 1936. J. D. PUGH 2,039,738

METALLURGICAL FURNACE Filed May 3, 1933 I 4 Sheets-Sheet 2 IIIIII j. IIHII .9 5 7" awe/nice y 6- J. D. PUGH 2,039,738

METALLURGICAL FURNACE Filed May 5, 1933 4 Sheets-Sheet 3 y 5, 1936. J. D. PUGH METALLURGICAL FURNACE Filed May 3, 1933 4 Sheets-Sheet 4 tap hole, as it is commonly called, is reamed out v Patented May 5, 1936 UNITED STATES METALLURGICAL muses John D. Pugh, Baltimore, Md. Application May 3, 1933, Serial No. 669,251

6 Claims.

This invention relates to metallurgical furnaces and particularly to furnaces of the type primarily intended for the smelting and refining of metals.

One purpose of the invention is to improve upon the present methods of and means for effecting the discharge of the contents of a metallurgical furnace of the stationary type, after the solid metallic materials of the charge have been reduced to molten form and are in a refined and proper condition to be withdrawn and transferred to suitable molds, suchas ingot molds.

It is now almost universal practice, and has been for many years, to provide metallurgical smelting furnaces with outlet orifices at or near their lowest points, which orifices are, during the time when the smelting operations are being carried out, closed with plugs of clay or other suitable refractory material. At the conclusion of the melting and refining operation carried out with respect to each successive charge introduced into the furnace, this discharge orifice or with suitable tools, the refractory plug being broken up and clearedaway so that the liquid contents of the furnace may escape in a continuous-stream, generally being conducted by means of an open runner to a mobile ladle having sufficient capacity to receive the entire charge of molten material held by the furnace. In such prior practice the charge flows continuously until the furnace is completely emptied of its contents.

In accordance with the present invention, the discharge conduit or tap hole of the furnace remains at all times clear and unblocked, and a novel device associated therewith, and adapted to be manipulated under the close control of the furnace operator, normally prevents the discharge of the molten contents of the furnace by causing the hydrostatic pressure tending to effect the escape of molten material through'the tap hole to be exactly counterbalanced bythe equal hydrostatic pressure of a column of molten material without the furnace and beyond the tap hole, the upper surface of.which lies in the same horizontal plane as does the upper surface of the I bath of molten material within the furnace.

. This means or device may be manipulated by the furnace operator so that the pressure of this counterbalancing body of molten materialwithout the furnace may be made less than the prestinue until the furnace is completely emptied of its contents or may be interrupted at any time after the desired amount of molten material has been withdrawn. In other words, there is substituted for the commonly used seal of refractory material a liquid seal which may be readily 5 controlled in a manner not possible in the case of sealing devices heretofore designed or suggested.-

The invention further contemplates an improvement in the means for and methods of cast- 10 ing into suitable units, such as ingots, the molten product of a smelting furnace,.the furnace operator having means at his disposal to closely control at will the delivery of molten material into the molds, the improved mechanism also greatly expediting the process of casting or teeming.

A further purpose of the invention is to provide means for facilitating and improving upon the known methods of smelting furnace operation generally, especially to provide improved means for and methods of operating the wellknown open hearth furnace, in which type of furnace the great bulk of the steel now commercially manufactured is smelted and refined.

The invention also contemplates improvements facilitating the operation of a battery of open hearth furnaces consisting of two or more such furnaces in close proximity, such batteries being commonly found in the larger steel plants of the country. Thus mechanism is provided by means of which it is possible to carry out at will, and without inconvenience or confusion, the simultaneous discharge of the contents of any number offurnaces comprising a battery and the .ready removal to a finishing plant of the series of molds into which the molten contents of the furnaces have been discharged. 1

Other objects of the invention and important advantages resulting from its use will be apparent to one skilled in the art from an examination of the accompanying drawings, in which several embodiments of my invention are illustrated, and from the following detailed descrip tion, in which the several forms of the invention selected for illustration by way of example are specifically described.

In the drawings;

Figure 1 is a side elevation, partly broken away, of an open hearth furnace of well-known type, to which the invention hasbeen applied;

Figure 2 is a transverse vertical section through the furnace at its mid-point;

Figure 3 is a side elevation of a portion of the furnace as viewed from the front;

Figure 4 is an enlarged vertical section taken axially through the mechanism foreifecting and controlling the discharge of the molten materials from the furnace, Figure 5 is a plan view of a portion of this mechanism, and Figure 6 is an end view of the same;

Figure 7 is a section on line |1 of Figure 1; -Figure 8 is'a view generally similar to Figure 2, takentransversely through a furnace of the open hearth type but showing a modified form of means for controlling the discharge from the furnaceand effecting the transference of the moltenmaterials to suitable molds;

Figure 9 isan enlarged sectional view through a portion of this mechanism;

Figure 10 is a fragmentary sectional view through an open hearth furnace, again showing a somewhat modified type of discharge mecha nism for the molten material;

Figure 11 is a rather diagrammatic plan view of a battery of open hearth furnaces showing the trackways-along which the trainsof molds are conducted to and from the furnaces in the ordi- 4 nary operation of the steel plant;

Figure 12 is a section on line l2--i2 of Flguri 11; and

Figure 13 is a section on line ll-it of Figure 11. i

As has been before indicated, the invention relates or pertains to metallurgical smelting or refining furnaces generally, not being limited in its'application in the industry to use in connection with an open hearth furnace. As one of its greatest fields of usefulness is in connection with open hearth furnaces, however, it is shown in the drawings as being applied "to such a furnace. Again, the detailsof construction of the open hearth; furnace may be widely varied, it being immaterial whether the furnace be gas-fired, oilfired, or fired with powdered coal or the like. The

details of the reverberatory lining, gas and air ports, buckstays, supporting plates, and other elements of the furnace are likewise immaterial. The furnace shown rather ticaliy in the drawings comprises the usual metallic supporting framework and the usual bottom, side walls, and roof of refractory material supported by this framework. The hearth or combustion or refiningchamber of the furnace, however, is

- separated from .ne furnace ends, as shown, and

' of the furnace is the weight of the refining chamber is transmitted to the ground or supporting base by means which permits the operator to weigh the contents of the metallic charge which forms the-bath, for

purposes hereinafter to be made-clear. I

Thus, as will be apparent from inspection of Figures .1 and 2 of the drawings. the entire weight of the central portion or refining chamber extending I-beams. indicated at II, theseI-beams being arranged in two groups ofthnee beams each.

The weight of this portion ofthe furnace is in turn transmitted to transversely extending supporting estals ll through hydraulic weighing devices, of which there are four, generally in'dicated at If, and the details of whiehwill be hereinafter specifically described. The furnace II and M respectively, water cooling dc are separatel supported upon the gro base-and no part of the weight of the materials used in the construction of these end portions is transmitted to the supporting bases l liil-The fur p d; from the ends of the combustion or refining chain-f nacej ends, of which there are two,

ber,'one of thenerrowseparating transverse verum, slot sor spaces being indicated at It, it being understood that the furnace in its entirety. is preferably symmetrical with respect to its transverse central vertical plane, the furnace end which is not illustrated being preferably the same in design as that which is shown and being also formed separately and spaced from the opposite end of the refining chamber in the same manner that the furnace end actually illustrated is so spaced.

A portion of the charging floor is indicated at It, the central opening in the side wall provided for charging the furnace and inspecting the interior thereof is indicated at H, and the vertically slidable door for-the opening I1 is indicated at it. The discharge orifice for the molten material is preferably positioned directly oppoture I9 is commonly termed the tap hole", and

it has heretofore been conventional practice to tory material prior to the time when the furnace is charged and fired and to remove this refractory plug bysuitable instruments after the metallic ingredients-of the charge have been reduced to molten condition and suitably refined, so that the contents of the bath are ready to be discharged 1 plug this hole with clay or other suitable refracfrom the furnace. In accordance with prior pra'ctice, the entire bath is allowed to escape once the refractory plug has been moved, being caughtand retained by a large casting ladle having a capacity sumciently great to receive this large amount of metal.

In accordance with the present invention,

' means is provided for effecting a liquid seal of the tap hole ll, this means comprising essentially a spout-like member II which, when turned in one direction or as shown in 1 and 2, maintains in its hollow interior a body ofmolten material of such height as to develop a static pressure at the tap hole equal to the,

static pressure of the liquidof the bath. As can be seen most clearly from an inspection. of Figure 4, member 20 is generally tubular, having a horizontal portion and a portion disposed at right angles thereto. It comprises a metallic shell indicated at II heavily lined "with a suitable refractory material indicated at 22, the actual discharge conduit for the molten being a central channel 23 of.circular cross'section' and I extending from end to 'end thereof, the outer end of this channel being flared as shown at 28'.

The inner end of member II is rotatably sup: ported within a short cylindrical collar N which isin turn mounted within a ring II rigi ly sup ported by the framework of the furnace. refractory lining 22 terminates, at the inner of the spout II, in a fiat annular surface, and tightly abutting, against this surface and extend ing beyond the end of the shell II is, an annular member or block 26. formed of smooth, den fractory material such as graphite, the opposite fractory block 26 moves with the spout II when the spout revolves about the horizontal axis of the supp rting ring 24. Rigidiy supported by'the structure is a secondblock 21 of graphite end surface ofthis block being spherical. Re-

or like dense and smooth refractory material, block 2! being centrally apertured. as shown, this central aperture comprising in fact a continuation of the tap hole l9, and the outer end of this central aperture being in register with the central aperture in the rotatable block 26. The outer surface of block 21 is annular and spherical, being concave so as to fit tightly against the adjacent surface of block 26. Blocks 26 and 21 are so formed with respect to the supporting ring thatthese members define, in conjunction with the aforementioned ring, an annular pocket, indicated at 28, which pocket is filled with a smooth, refractory, pulverulent material such as powdered graphite. The annular collar 24 is secured to ring 25 by a plurality of bolts 29, which bots may be adjusted from time to time when found necessary to'move collar 24 toward and partially into the pocket 28 so as to place the pulverulent material contained in this pocket under suitable compression. It is the function of the compressed pulverulent material to prevent leakage ,of molten metal past the abutting surfaces ofblocks 26 and 27.

A supporting bracket 30 rigid with the framework of the furnace chamber has detachably affixed thereto at 3| an extension 32 which pro-- jccts outwardly and upwardly, supporting at its upper end a bearing 33 disposed coaxially with.

the horizontal axis of the spout 20 and adapted to rotatably support a trunnion member 34 rigid- 1y attached to the shell 2| of the spout. Bearing against the outer end of trunnion member 34 is a transverse plate 35 apertured to slidably receive spaced parallel bolts 36, the inner ends of which are connected to bearing block 33 and the outer ends of which are threaded and provided with adjusting nuts 31 which define the positions respectively of circular spring abutments 38, between which and the transverse member 85 are confined the coiled compression springs 39. It is the function of these springs to exert an inward axial pressure on trunnion 34 which constantly urges the inner surface of refractory block 26 into close contact with the outer surface of block 2'1, thus preventing leakage of molten metal past the abutting surfaces of these blocks. Trunnion 34 is detachably secured to the shell 20 of the spout by bolts 40, and the inner end of the trunnion member likewise confines in position a tapered plug 4| of refractory material, which in reality forms a portion of the refractory lining 22 of the spout.

' From the above description it will be clear that ring 24 supported by thefurnace structure and in part by the bearing block 33 which is coaxial with ring 24, and that therefore the spout may be revolved about its horizontal axis through a wide angle in either direction of rotation from its vertical position, as shown in the drawings.

In order to effect the rotation of this spout .by

power, a motor 42 is mounted upon the top framework of the furnace chamber, which motor, through suitable reduction gearing, operates a pulley or sheave 43. A suitable cable, wire rope, or sprocket chain 44 passing over sheave 43 also passes around the grooved pulley wheel (or sprocket) 45 rigidly mounted upon the horizontally extending portion of the spout. The motor 42 is preferably of the type whichmay be rotated in either direction so that, by the proper energization of this motor, the spout may be rotated to desired position.

Normally, that is, while the furnace is in operation with a charge on the hearth, either reduced to molten condition or in process of such reduction, the spout is disposed as shown in Figures 1 and 2 of the drawings, in which position it holds and sustains a column of molten material, the level of the upper surface of which is in the same horizontal plane as the level of the upper surface of the bath contained within the refining chamber of the furnace. The two bodies of liquid are then in hydrostatic balance at the tap hole, and there is no flow through this discharge orifice. During this time it is generalsy desirable to have above the open upper end of the spout a cover to prevent undue radiation of heat, which might result in the freezing of the upper surface of the molten material in the spout, that is, in the formation of a "Scull." Such a closure is indicated at 46 and, as shown, comprises a downwardly facing flanged metallic disc 41 lined with refractory material 48, the disc being rigidly secured to a member 49 having one end fastened at 50 to the furnace frame and its other end supported therefrom by means of a cable iii. If desired, means is associated with the cover 46 for conducting fuel and air therethrough, such, for instance, as conduits 53 and 54, so that a flame may be maintained below the cover and above the upper surface of the liquid standing inthe spout, for the purpose of imparting additional heat to this liquid to prevent its hardening.

The cover likewise comprises a support for the spout when it is desired to remove the plug 4|. for the purpose of cleaning the spout and tap hole. Thus a socket 55 fora bolt or similar means is attached to the cover, and a second socket or bolt retaining device 56 is attached to the spout near the outer end thereof. By connecting the sockets or brackets 55 and 56 by bolts or attaching devices, the weight of the outer end of the spout may be transmitted to. the cover and thence to the frame of the furnace through the supporting cable 5! so that it is then possible for the operator to remove the detachable supporting bracket 32, trunnion 34, and refractory plug 4!, so that free access may be had to the interior of the horizontal portion of the spout and the tap hole end surface, and the cover is provided with a the weight of the spout is carried in part by the correspondingly tapered surface to fit tightly against the same so that the cover forms a substantially air-tight closure. Air or other gas may be introduced by means of a pipe 46' under such pressure as to insure its passage through the spout and tap hole into the bath, through which it will rise. The introduction of compressed air in this manner will result in the oxidation of some of the molten contents of the bath, and the heat thus generated will counteract any tendency of the metal to freeze in the tap hole, thus keeping it open by means under the control of the operator. Again, it may be desired to maintain a heating flame within the upper end of the spout above the surface of the molten material therein, in which event a conduit 46 for gaseous fuel may extend through the cover. Where the spout is thus heated, it is preferably water-cooled, as by an annular cooling water chamber 20' connected' A suitable aperture for the escape of products of combustion will, of course, be provided.

The spent 28 may be revolved inveither direction of rotation by the power means previously described, and, when it is desired to deliver molten material to ingot molds, for instance, the

spout is rotated to the left. (Figure 1); or in a counter-clockwise direction, so that its delivery end is lowered below the level of the upper surface of the'bath, thus causing a fiow of metal through the tap hole-and spout. This metal is delivered over the lower edge of the mouth of the spout into an inclined runner indicated at 80,

/ which are positioned the trackways along which recarburizing material through 88 to supplement the-molten metal delivered in this manner into the runner flowing downwardly to its lowest point and thence being transmitted by means of the substantially horizontal tubular runner 82 into the interior of a stationary pouring ladle, indicated'at 83. Both the runners 88 and 82 and the ladle 62 are supported upon a suitable bridgelike framework, generally indicated at 84, beneath the ingot mold supporting cars may be moved. Ladle 83 is preferably provided with three discharge apertures in its bottom, one of which is indicated at 85, the flow through each of these apertures being controlled by any well-known or suitable valve device 88, operable from the top ofladle 83,: or from a distant point, as from the platform 81 upon which an operator may stand and from which position he is able to look into the top of an ingot mold, indicated at 68, positioned below aperture 85, and hence to control the dis- I charge of molten materials in such manner that the ingot mold may be filled but not caused to The tubular member 89 guides the.

. overflow.

downwardly fiowing ,stream of molten material to the immediate proximity of the mouth of the mold.-

Each of .the mold cars 10 supports three ingot pose'of making it possible to conveniently fill a plurality of ingot molds with molten material simultaneously, and other means for accomplishing this same purpose may be'provided, if desired. A pouring ladlesuch as indicated at 82 is preferable, however, since it provides a sub-- stantial reservoir, of molten material, in relatively quiescent state, immediately above the molds, thus insuring that the'pouring operation is conducted in a steady and rapid manner. It also provides a chamber for the introduction of or substitute such operation in the furnace. An indicator ii is provided for the convenience of the operator uponplatform 81 this indicator having a float which'rests upon the surface of the liquid within the ladle 81 and showing the operator how much liquid is contained therein at 0 any time. For the purpose of maintaining a heatingfianie within ladle 83, either when the container is empty or partially fulhits roof is perforated for the admissionjof a fuel pipe I2, by means of-which, for instance, a combustible gas may be discharged'into the upper-pert of .mitted to the base through four the ladle. If necessary, passages for air and products ofvcombustion may also be formed in the ladle roof. The flow of molten material to the ladle, of course, is accurately controlled by the manipulation of the pouring spout 28.

A second inclined runner, located to the right of the pouring spout, is indicated at 15 in Figure 1, this runner having communicating with its lowest point a horizontal tubular runner 1.6 for conducting molten materials in a generally horizontal direction to a downwardly directed delivery spout I'I. In the event that it is desirable to discharge all or any portion of the bath into a ladle of the mobile type, such ladle may be placed beneath the discharge orifice of conduit 11, the pouring spout rotated in a clockwise'direction (Figure 1), and the desired amount of molten material withdrawn from. the bath in this manner. By the proper manipulation of the spout, slag may be diverted to a mobfle ladle for disposal and metal only caused to flow to the pouring ladle 83. Likewise it is possible to remove that portion of "the bath which lies at the general elevation of the 'tap' hole, discharge it into a mobile ladle, and then pour it back into the bath for further refinement through an aperture in the furnace wall provided for that purpose, this aperture being indicated at 18 inFigure 10 and the furnace be1n8 provided exteriorly with an inclined lip or trough-like extension 18, normallyciosed by a tilting co'yer 80 for guiding the molten material discharged from a ladle, such as that indicated at M, through the furnace wall and into the bath. By the means just described,=it is possible to secure a more thorough intermixture of 'the metallic ingredients of the bath than can normally be obtained.

In certain instances it may be desirable to omit the relatively large pouring ladle 63, and in this event the inclined runner may lead'the discharged metal to a horizontal tubular runner 82 which has a downtumed end 82' terminating in a-discharge port 82 positioned immediately above the upper end of a mold or above the open mouth of a'ladle such as shown at iii in Figure 10. Flow through the runner 82 is controlled by means of-a valve. of any well-known type,

which valve is manipulated by means of a rod or tube 88, protected'withrefractory material, which projects through the wall of tube 82 and to the end of which maybe connected a cable such as indicated'at 88. If desired, the runner 82 may bebranched so-as to have a-plurality of downwardly projecting metal delivering ends so that it is possible to deliver molten metal to each of two or three ingot molds simultaneously. Generally, however, I provide in connection with each fumace-a single runner 82, thus necessitating filling one mold at a time. The pouring spout and furnace of Figure 8 may be identical vwith those shown'in Figures 1 and 2.

I have previously explained that the entire weight of the furnace combustion chamber, pouring spout, and charge held in the furnace is trans- I devices, generally indicated at l 2, and by means of which the weight of the furnace and bath may be determined.

One of these devices J2 is shown' in section in Figure 7. The several beams II are bolted to a rectangular member-ll to which is centrally affixed a plimger 8|. Plunger 8i is' shaped as a short cylinder and slidably fits withina ring 82 supported upon a rectangular block 98 resting upon base It. Ring 82 is tightly bolted to" a circular disc-like member 84. Immediately below the plunger 9i lsa flexible diaphragm 9i, the margins of which are tightly clamped between ring 92 and disc 94, a small quantity of fluid being trapped between the diaphragm and disc 94. This fluid may conveniently be glycerin, and a pipe or conduit 95 provides the sole means ofingress of glycerin into the chamber below the diaphragm and the sole means 'of escape therefrom.

The several fluid pressure chambers, of which there are four, are brought into communication with an indicating gauge by pipe connections,

not illustrated, such gauge, however, being shown at 95in Figure 3. The gauge is so calibrated as to indicate the weight of the furnace and its contents in any suitable units of weight. For a complete description of the details of the indicator and the scale system in general, reference may be had to my prior Patent No. 1,579,658, granted April 6, 1926. It need only be said here that, after the weight of the furnace structure itself has been determined by the operator, he can without difficulty determine with exactness the weight of the charge on the hearth and may know at all times how much metal is in the furnace. l'he indicator, therefore, is of assistance in the event that it is desired to operate the furnace in a continuous manner rather than by the batch method, since the operator is able to replace any quantity of metal withdrawn by the exact amount of fresh metal.

By means of the novel pouring mechanism described, therefore, it is possible to operate a stationary furnace so as to realize all of the 35 advantages to be derived from the use of a tiltrecarburization purposes.

ing furnace, without at the same time having the complicated structure of the tilting furnace. I also preferably provide the furnace with an aperture in the side wall, in this instance placed directly opposite the tap hole, for the introduction of molten material. This aperture is indi cated'at 91 and may be conveniently positioned directly below the. charging aperture I'I so that its upper end maybe closed by a horizontal projection I8 of door it when this door is lowered into position to close the charging opening II. When the door is raised, molten material may be introduced into the bath below the surface thereof for the purpose of replenishing the supply of molten material to be refined or for shown at 9'! is particularlyuseful tor c 'out rec'arburization processes since the reearbw rizing metal may be directly introduced into the main body of the metal on the hearth without passing through the layer of slag always present on the surface of the metal. Asmall mobileladle is indicated at 98 and is shown to be in position to discharge liquid into the upper end of the channel Q1.

Referring now to Figures 11, 12, and 13. Here a battery or six furnaces is illustrated, these furnaces being placed end to end and in what may be designated axial alignment, as.is'customary practice in steel plants of substantial size. The three left-hand furnaces indicated at I00, MI and I02 are provided with discharge controlling spouts, such as shown in Figures -1, 2, and 4, and also with stationary pouring ladles 03,,such as illustrated in Figures 1 and 2. The three righthand furnaces I03, I04, and I05 are provided with pouring spouts and with runners of the type shown in Figure 8 of the drawings, pouring ladles such as 63 being omitted.- Four separate trackways for trains of mold cars are indicated at I06,

A conduit such as I01, I08, and I09 respectively, cross-overs for these trackways being indicated at IIO, III, H2, H3, I I4, and I I5, by means of which the trains of mold cars may be moved from track to track. On each of trackways I06, I01, and I08 are shown diagrammatically two trains of mold cars, six trains in all or one for each furnace, with each train located at the pouring mechanism of the adjacent furnace in two different positions. The train extended to the left (cross-hatched) indicates its position after molds are filled and before departure to the finishing mills. The position of the same train prior to filling of the molds is shown at the right (not cross-hatched) The length of the train and spacing of the furnaces are adapted to permit a complete train to extend from the pouring apparatus without blocking free movement of other trains on cross-overs between adjacent tracks.

The pouring apertures of ladies 63 of furnaces ms, MI, and I02 are indicated diagrammatically by dots 65, and it will be seen that the pouring apertures of the ladies 63 associated with furnaces IUI and I02 are positioned so as to overlie respectively trackways I06 and I0? so that the contents ofthese ladles may be discharged vertically downwardly into the ladles passing below. In the case of ladies $3 of furnace I00, the tubular guides 68 associated with the discharge apertures are downwardly and outwardly inclined so that the discharge ports of these tubes overlie trackway M38 or, in other words, are in position to conduct metal to the ingot molds supported on cars moving along this trackway. In Figure 2 of the drawings, one of these downwardly and outwardly curved tubes 68 is indicated in dotted lines. In the case of furnaces I03, I06, and M5, metal runners 82 difier in length so that the discharge ports 82 of these members overlie respectively the several tracks W6, W7, and I08, as will be apparent from an inspection of Figures 11 and 13.

By an arrangement of molten metal discharge and pouring devices such as described, and with an arrangement of trackways and switches such as set forth, it is possible to completely discharge the contents of all six furnaces of the battery simultaneously into ,molds and also to remove any one of the several trains from the proximity of the furnace without necessitating the removal or shifting of any other train. This follows from the use of the various cross-overs shown and from the use of the single running track, indicated at 509. From an um.- of Figure 11, it can readily be seen that any one of the trains may be removed to the running track by moving it over the proper switches without conflict with any other train. It is, of course, true that in no case will six furnaces of a battery be simultaneously tapped. but nevertheless it is highly desirable that the pouring devices of a battery be so organized and the trackways so arranged that any two or three of them, or even more, may be simultaneously tapped should by any chance the necessity for doing'so ever arise. This is particularly true where it is intended that the furnaces shall be operated in a continuous manner.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. A stationary metallurgical furnace comprising a hearth provided with a constantly open disnace wall for controlling the flow of molten terialthrough said port.

2. A container for molten materials having a constantly open discharge port or tap hole formed in the wall thereof at its lowest point, the discharge end of the tap hole being encircled by a portion of the container having an outwardly'facing annular surface, a pouring spout supported exterioriy of said container, one end of which has an annular surface in contact with the annular surface of the Container, said spout being rotat able about the common axis of said contacting" annular surfaces so that the opposite end may be moved to a position above or below the level of v the surface of 'the metal in the container, as desired, and resilient means constantly acting on the spout and urging the annular surface thereof into close contact with the annular surface of 4. A metallurgical furnace comprising a hearth, a mold positioned laterally of and below the hearth, said mold having less capacity than the hearth, a pouring spout permanently associated gravity.

with the furnace and adjustable relatively thereto to initiate or interrupt flow of molten material from the bath upon the hearth'at the will of the operator, and means for delivering molten material issuing from said spout to said mold, by

5. In combination, a metallurgical furnace having a, chamber for retaining a body ofmolten metal, said chamber having a constantly open discharge port in its wall, a pouring ladle fixed with respect to the furnace, and means for conducting molten metal from the furnace discharge port to'the pouring ladle including an adjustable conduit for the molten metal which may be moved to metal pouring or flow interrupting position as desired, whereby measured quantities of molten metal may be withdrawn from the furnace at desired intervals. t V

6. A metallurgical furnace comprising a hearth,

a mold positioned laterally of and below the hearth and having a. capacity less than' that of .the hearth, and a movable flow regulating device permanently associated with the furnace for con? trolling the escape of molten metal therefrom and for conducting such metal to the mold, whereby a measured volume of molten metal may be allowed to flow from the furnace to the mold by gravity and the remainder confined within the furnace.

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