US2013905A - Circular ingot heating furnace - Google Patents

Description

Sept. 10, 1935. J. ADAMS, JR 2,013,905

CIRCULAR INGOT HEATING FURNACE Filed Feb. 4, 1935 5 Sheets-Sheet l INVENTOR Sept. 10, 1935. Y ADAMS, JR 2,013,905

CIRCULAR INGOT HEATING FURNACE 9a. 4 is), E's. 3- E/ 'INVENTOR Sept. 10, 1935. J. 1.. ADAMS. JR

CIRCULAR INGOT HEATING FURNACE I Filed Feb. 4, 1955 5 Sheets-Sheet 3 FIE. M5 175. //E Z 75. l/5

FIE. lE-T link ALTA 3 I; y J

""IIIII/ IIIIII Sept. 10, 1935. J. 1.. ADAMS, JR

CIRCULAR INGOT HEATING FURNACE 5 Sheets-Sheet 4 Filed Feb. 4, 1955 F111 lNVENTOR I Patented Sept. 10, 1935 UNITED. STATES PATENT OFFICE 2,013,905 CIRCULAR, INGOT HEATING FURNACE James L. Adams, Jr., Youngstown, Ohio Application February 4, 1933, Serial No. 655,185

15 Claims.

The present invention relates broadly to the art of heating metal ingots, and equalizing their temperature throughout, preparatory to rolling, and more particularly to the heating up to proper and uniform rolling temperature, of annular or ring ingots, such as may be used to advantage in a continuous belt-mill, such, for example, as that covered by my ,co-pending application, Serial No. 674,661, filed June '7, 1933.

One object of the present invention is to provide apparatus especially adapted to the very uniform heating of relatively thin and wide ring ingots in a minimum time.

Another object is to provide apparatus which will do the heating without producing cooler belts around the ingot corresponding with the usual lines of support thereof.

A valued object is to provide apparatus through which the ring or other ingot will be progressed while undergoing slow rotation around its generating axis, so'as to bring all perimetral surface points therein into contact with substantially the same total amounts of heat.

A further important object is to provide a furnace such as will permit individual time periods of heating for each individual ingot, without holding up the general progression of ingots therethrough by so doing; which will also allow any contained ingot to be spotted and withdrawn independently of all the rest, and which will allow any vacated position to be likewise filled up independently of its position in the general series along the furnace interior, and without disturbing other ingots therein.

As a further object I may sometimes provide an ingot heating system, which contains two furnace stages in tandem, so that red or yellow-hot ingots direct from the stripper of casting machine can be fed through the final stage only, while cold ingots taken from the storage tracks, can be put through the two stages in tandem, in any order or quantities respectively required, and all delivered fully heated to the mill, in proper sequence, and in any required proportion therebetween, with each ingot given its own selected time in the heat, as the pyrometer utilized may dictate.

An added object of importance is to provide a furnace with a herring-bone type ofdeeply fluted cohtour thereof, as to lead to a concentration of the radiation therefrom upon those areas of the ingot underneath, which normally require the most heat to quickly bring to uniform rolling temperature, or upon those elements of the ingot which normally tend to be insufliciently heated,

in the usual furnace.

One prime object is to get all bearings carrying rotating parts, well below the lower floor of furnace, where the temperatures encountered will 10 be moderate.

Another object is to carefully stagger or offset the surfaces contacting directly with the ingot, or give them a wavy-outline on the bearing points against the, ingot, so as to decrease the total time of contact of any one point on the ingot, with the relatively cool supporting elements below, and not produce a cold-streak around the ring, which would introduce difliculties during the rolling later on.

An added object is to provide a furnace system of such type that simple and sturdy' selectivecharging, transferring, and ingot-withdrawing means can be readily adapted thereto, and operated without material waste of hot-gases at such points.

One more object is to provide simple sand or other sealing, between the moving and stationroof surface, designed to divert the actual gas flow toward those elements of ingot which normally tend to come through the usual furnace under-heated.

Another object of considerable value is to so shape the roof of furnace, or the interior crossary parts, to substantially avoid hot-gas wastes here.

A comprehensive object is to for the first time produce an apparatus which combines tlie advantageous elements of all the above objects in one machine.

Still further objects will be self-evident to anyone skilled in the art to which my invention appertains.

With all the above and other objects in view,

I have provided suitable apparatus of a preferred form, for practicing my invention, and quickly40 bringingwide, thin-walled ring-ingots, such as those covered by my co-pending application Serial No. 649,181, filed December 28, 1932, to a suitably high and uniform rolling temperature, and delivering them successively into proper position "convenient for transport to mill, by some such device as that covered by my co-pending application on Ingot transport apparatus, Serial No. 652,142, filed January 17, 1933.

In the accompanying drawings 1 have shown for purposes of illustration only, andnot as determining the limits of my invention, or the scope V of its application, one preferred form of apparatus constituting such invention, and two alternative forms. v

In these drawings, Figure 1 is a vertical cross section of one side of my annular furnace, taken on the line II of Figure 2A, looking in the direction of the arrows.

Figures 2A and 2B are horizontal cross sections of the interior of two slightly different forms of my furnace one circular, and the other hexagonal in outline, either of which may be considered as taken on the line II-II of Figure 1, and also looking with the arrows.

Figure 3 is a view, taken partly in verticalcross section and partly in elevation, on the line III-III of Figure 2A, -in the direction of the arrows, and shows an ingot transfer mechanism.

This transfer arm can be readily adapted to charging, or to intra-furnace operation, if so required, with only evident changes in structure.

Figure 4 is a general plan view of my preferred twin-furnace layout, and indicates the ingot-transfer locations: both intra-furnace and between the outside ingot-car tracks and the respective furnaces, the view also indicating some of the more directly associated items of mill equipment. The transfer positions shown may be altered, however, and in many cases but a single furnace used.

Figure 5 illustrates in yertical cross section on line VV of Figure 2B, and looking in the direction of the arrows, a preferred type of entrance and exit door system for my furnaces, whereby charging, transfer, or discharge of ingots can be carried out rapidly, and substantially autom-atically,-without serious loss of hotgases during the transfer periods. But other doors,as per Figure 7, might be substituted.

Figure 6 shows a vertical cross section, taken on the line- VIVI of Figure '7, in the direction of the arrows, of an alternative form of my heating furnace, likewise adapted to the handling of ring or other rotatable ingots, but in which the furnace itself is of the slightly inclined and straight-run pattern, on the sloping tracks of which the successive ingots may roll of their own accord, but slightly spaced by, and under the retarding speed control of, light guiding discs carried by a chain drive.

Figure 7 is a vertical longitudinal cross section of such a straight furnace, taken on the line VIIVII of Figure 6, and again looking in the direction of the arrows, so that the caterpillarchain system, with its associated guiding-discs, are shown in elevation, also the driving sprocket therefor.

Figure 8 is an underneath view of a roof refractory assembly using square blocks, shown looking upward toward the furnace ceiling, from r the line VIII-VIH of Figure 6, and indicating by the shading the general direction of the under surface fiuting, one refractory unit being made to stand out by the use of heavier lines, to show the shape. I

Figure 9 is a view taken from the same point as Figure 8, but showing an alternative hexagonal refractory assembly, of the split-hexagon type, with one unit emphasized by heavier lines, as in the case of Figure 8. All units shown oversize for clearness.

Figure 10 illustrates, from the same point of view as Figure 8, an alternative assembly of diamond-shaped refractories, with one unit emphasized as before.

This alternative form may be flat-ended, the

required ceiling corrugations being produced by lowering alternate slanting rows of the refractories, thus giving a grooved effect.

Figures HT, 113, 11S, and 11E, show the top, bottom, side, and end views respectively, of one of the square type unit refractories, and bring out the fiuting underneath.

Figures 121, 12B, 128, and 12E are similar, but show a split-hexagon unit, which is much easier to build in to the approximate pattern indicated, should thefurnace happen to be of '10 the hexagonal, or circular type, than is the square unit. l

Figures 13T, 13B, 13S, and 13E show similarly the different aspects of .a diamond-shaped refractory, just as was above outlined for the 15 others.

Figure 14 is a plan view looking down upon the top of the apparatus shown in Figure 3, and illustrating the inmrconnection between transfer-arm and the .furnace doors.

In all these figures, corresponding elements are indicated by the same part numbers.

Referring now more particularly to Figure 1, my furnace is shown at I with side-walls suitably lined with high temperature fire-brick or equivalent refractory, while on the outside there are positioned the heavy and appropriately spaced vertical buck-stays 2 of structural steel or' cast-iron, and preferably supporting the longitudinal steel channels or other structural shapes 3, which in turn carry at short intervals. the cross pipes or beams 4, to which are attached the roof refractories 5 through the agency of the T slots 5a, or equivalent means, into which the small steel strips, rods, or equivalents 6, are interlocked by well known means and their top ends attached to or clamped around the cross pipes 4, the several lengths of 6 being appropriately selected to give the required roof curvature for best concentration of the gas-flow and the 40 roof radiation upon desired elements of the successive ingots. These refractories 5 are preferably, but not necessarily, given a very deep and angularly directed bottom end fluting 1, with the angles so opposing on the two sides of the longitudinal ceiling centre-line as to give 'a pronounced herring-bone effect, utilizable to gradually direct the hot-gas flow toward those axial positions along ingot which normally require most heat, as will be gone into in more 5 detail in a later figure, where it will be noted that I have so designed the several refractory blocks shown that one type of block only is required to give the two herring-bone" angles, and also to enable fitting right up close to the furnace wall on each side, the hexagonal blocks being therefore all made split to permit this. For a straight run furnace, any one .of the blocks shown may be used; but for my preferred hexagonal or circular type of furnace, the hexagonal blocks are generally found more adaptable to the work, as they allow successive 60 shifts.

The concrete floor or base 8, of generally annular or hexagonal plan, carries'a heavy top lining 8a of fire-brick, in turn supporting the annular baffles 9 and So, also of very high temperature resistant fire-brick, which baflles are conveniently sub-divided into sections of say four or five feet length each, with perhaps an inch or so spacing therebetween, and made easily separable from M on the line of the or A thick sectional base-plates ID, if occasion' should require.

Water-cooled ingot end-thrust guides, or

stops S, are supported by these plates I ii, the

water connections being omitted, as of usual construction, and well known, and although a pipe has here beenutilized as a simple form of stop, substitutes will be self-evident, and may in some cases be preferred to that shown.

While my furnace has been especially designed to handle ring-ingots, it will be noted that any other shapes which can be rotationally progressed therethrough may be operated upon equally well.

A ring-ingot R. I. is rotatably carried upon the high-temperature resistant disc-wheels l l, I la,

and Nb, all of which present to the ingot wide edges Hc of decidedly wavy contour, so as to stagger the points of contact with ingot repeatedly and prevent undue heat abstraction around any one circular belt thereon.

, These disc-wheels ll. Ha. and lib are in turn mounted by means of the very-large-ball bearings I2. upon the horizontal shafts I3, l3a, and I317, the bearings being carried by the plate-steel frame 14, of the annular carriage [4a, supported by the flanged wheels I5 and I5a, which it will be noted are of different respective diameters appropriate for rotation slowly around the general centre-line I517 of the annular furnace, and are carried on shaft l6, by the bearings l1 and l1a. the whole being supported upon the tracks I8 and 18a, the latter of which may be raised somewhat, if so preferred, upon block I9, carried by the steel tie 29, which is here made short so as to provide space for the headroom of main tenance-tunnel 2!, under the, furnace. Annular carriage M11 is driven by the heavy pinion 22, of coarse tooth type, appropriately meshing with the underneath toothed surface of rack 23 of carriage, and driven by suitable means through the extending shaft 26. The disc-wheels Nb and shaft I3b are slowly rotated as carriage |4a progresses. by the coarse-toothed spur-gear 25. suitably shielded on top by the apron 26, and meshing underneath with the stationary annular rack 21, mounted on supports 28, bolted to tunnel-wall.

Thehigh-temperature brick fill of carriage I40, and plate lining l 4, is indicated at 29, with its appropriate surface layer of still higher temperature fire-brick shown at 30, while 3| indicates the annular sump or slag well adjacent to wall of furnace. with 32 the general mill floor level. One of the numerous and appropriately distributed gas or oil burners is shown at 33, connected to main 34 through usual valve 35. The interlocking elements of a Sand-seal are shown at 36 and 31 respectively, the sand content being pointed out at 38, while occasional slag drainage channels thru the furnace wall are illustrated at 39, all draining into sump 3|.

Referring now to Figure 2A, about the only new parts disclosed beyond those'just enumerated, are the occasional radially positioned baffle-walls- 40, 40a. designed to prevent too much direct shunting of hot-gases by the furnace areas beyond each end of the moving ingot, but which conceivably might be dispensed with in some cases, as for a furnace of hexagonal outline such as that shown. in Figure 213; also the exhaust gas uptake or stack of the general furnace gases, while the long arrow 49 indicates the general course of travel of carriage I ia. The burners 33 of the preceding figure might be supplied with heated tar, or pulverized coal, as alternative fuels, and run reducing so as to prevent scale formation on ingot.

In some cases a single very largegas, or oilspray mixer, and burner might be used.

In Figure 3, I have shown one preferred form of ingot-discharging mechanism, such as might be used between the furnace I, and the outgoing tracks 44, but which, with relatively minor and obvious modifications, may be used between the two or more sections of a multi-stage type of furnace, such as will be outlined in a subsequent figure; or for furnace charging, as from tracks similar to those shown at 44.

Such transfer means, while claimed. and more fully disclosed, in my co-pending divisional ap-- jecting end the bevel-gear 52a, keyed thereto by the narrow key 521), operating in the relatively wide key-slot 520, so as to give some lost motion to gear, and all in turn carried by the large bearing 53, also of very considerable length, at top of heavy pedestal 53a, suitably carried by concrete base 53b, while at outer end of said transfer-arm 50, there is provided the substantial stub shaft 54, oscillable between this point and its second limit position 54a, over the course indicated by the twin arrows 55, 56, above, by means of the large diameter gear 51, meshing with smaller pinion 58, in turn driven by the worm-wheel 59 keyed on same shaft therewith, the latter wheel being functioned by worm 60, and motor 6!, of the reversible type, or some equivalent means. 7

Shaft 54 carries the tongs or grab- arms 62 and 63, mounted scissors-like so asto be freely revolvable on said shaft,,and carrying the respective pawl-tips 64 and 65, while counterw-eights 56 and 61 at opposite ends of the grab-arms partially balance the latter. As best shown at left-hand end of swing of the arm 50. counter-weight 61 carries the stop 58, and a fairly heavy projecting pin 69, upon which is mounted freely the heavy pawl 10, integral with, but axially displaced from, the operating lever or cam 1|, which in turn is limited in travel by the above stop 68, and in the other direction by the depth of the ratchet groove 12 on arm 62. Under each of the arms 62 and 63, a roller 13 is mounted integrally therewith, but

.freely rotatable.

As the right or 54a end of the travel of arm is neared, cam 1| is thrown over to the right somewhat by contact with the projecting roll 14, mounted in proper position upon the substantial arm 15, either bolted to, or cast integrally with the pedestal 53a, before mentioned.- It will be noted that the extreme 54a position of arm 50, is well below the position in which 62 and 63 are detailed at the right-hand end of swing, in order to make sure that the pawl-ends or tips 64 and 65 will fall well below the upper wall of the" ring-ingot R. 1., and hence be sure to pick up the latter when arm 50 again begins to rise, as shown Thisin detail drawings here in dotted outline. extreme position of the tips 64 and 65 is indicated at 64c and 65a.

0n now transferring this ingot R. I to the 54 shaft position as shown on the figure, or to lefthand end of travel of arm 50, via course 56, then if, and only if, a receiving ingot-car be thereunder in proper position, thedownward travel of the ingot will be arrested thereby, but arm 50 proceeds onward a little further, rolls 13 contact with ingot and spread the tongs 62, 63, until pawl 70 finally latches into groove or notch 12 of the other grab-arm 62, and thereby retains the tongs in fully-opened position, just after which step the limit-stop roll 16 must be set to function definitely, opening the normally-closed contacts H, which being connected in series with the shunt operating coil for forward throw of contactor supplying motor 6|, the latter is immediately stopped as said contactor (not shown) opens up.

The moving cam-surface 18, which functions roll 16, mounted on the end of a pivoted switch arm carrying one of the TI contacts, is itself conveniently mounted near one axial end of counterweight reserving space for another cam-surface axially displaced, -.from 18, to be mentioned later.

If no ingot-car be under arm 50 as ingot swings down at left, the arms 62 and 63 will not release said ingot, so no harm will be done, but by placing a normally-open type of limit-stop close to track 44, so that its roll 160. will be depressed by the front wheel flange of car, and connecting its contacts Ha likewise in series with the forward throw shunt coil of contactor above mentioned, motor 6| will be prevented from functioning arm 50 in the left-hand direction, unless said car be in proper position under the arm just mentioned.

The right-hand travel of arm 50, as indicated by arrow 55, is terminated by limit-stop roll 19, with its associated normally-closed contacts 80, functioned by the second and axially displaced cam-surface 8|, also mounted on counter-weight 5|.

These contacts 80 serve to open up the reverse running shunt-coil circuit of the doublethrow contactor provided for motor 6|, thus stopping the latter, as the terminus of cam BI is reached by roll F9.

The housings for contacts 11 and 80 are conveniently mounted upon pedestal 53a.

To make sure that moving ingots within the furnace will always have been stopped, and in proper exact position to register with arm 50, be-

fore the latter can be made to enter the furnace doors, a limit-stop roll 19a, mounted upon a contact arm carrying normally-open contacts 80a as well as normally-closed contacts 80b, is suitably supported near edge of carriage Ma of my hexagon or circular furnace, for example, so as to enter periodically into the indexing notches 840., thus momentarily closing 80a and opening 80b. But all this indexing, roller, and contact mechanism may, of course, be placed in pit, under the furnace proper, in order to get away from the heat. Now the last mentioned contacts are connected in series with shunt operating-coil of conwhile at the same instant contacts 80a, in series with the reverse contactor shunt coil for motor 6|, close, and thus permit latter motor to function in furnace direction. I prefer to-parallel the 88b contacts with a hand-operated single-pole, single-throw switch 800, as indicated, however, so that the moving elements within furnace can be made to run past all index-stop positions without stopping, whenever this may be' desirable, as when'none of a new batch of ingots is yet ready for rolling, or when mill may be temporarily held up, for re-adjustments, or re-placements, for a few minutes or more.

This switch 800 also serves to make the furnace selective, as to which ingot is to be next withdrawn from the entire group undergoing heating, and may be conveniently under the direct control of the optical-pyrometer observer, thus enabling him to determine the sequence of ingots directly, for transfer to the mill.

The functions of parts 52a, 52b, and 520 will be indicated in connection with a later figure, showing the pperation of self-opening furnace doors.

Turning now to Figure 4, new parts not previously cited appear as follows: a high-speed, high-output centrifugal casting unit, producing jarred steel, as per my co-pending application Serial No. 680,570, filed July 15th, 1933, is illustrated at 82; a high-speed belt mill at 83, with its proper live-roll table systems, and heavy motor drive; while 84 indicates an ingot-car, the details of all of which may be ascertained by reference to the appropriate applications, already cited.

My twin heating-furnaces are indicated at 85 and 86, although usually one only will be in use at a time, while transfer-arms, very closely associated operatively with my present invention, are shown in plan-view at 81, 88, 89, and 9|], although under a modified disposition, this number might conceivably be cut to one.

As here shown, however, furnace 85 would be assigned to the preliminary heating to about red-heat or a little more, of all initially cold ingots, such as those taken from storage, which are charged via transfer-arm 81, and then later transferred to the second-stage furnace 86 by the arm 88, for final heating to full temperature and soaking, after which they would be transferred to the ingot-car 8'4.

As the more usual case, however, initially redhot ingots taken direct from the casting unit 82, would enter furnace 86, via transfer-arm 89, and leave it for the ingot car via arm 90; or arm 89, with readily made modifications, might conceivably be utilized both for charge and discharge here, if so preferred.

Storage tracks for extra ingots from casting unit 82, are indicated at 9|, these tracks being amplified in extent as required, and used to provide an emergency store of ingots, or to absorb temporarily the production of casting unit, in

case a furnace happens to'be out of commission for an hour or two, or even longer. I

A suitable cross-transfer for these hot or cold ingots is shown at 92, usually in theform of a wheeled car, properly motor driven, or otherwise. This general plan had to be fore-shortened somewhat asindicated at 93. Referring now to Flgure 5, new parts not previously listed include the two cast or plate metal over-head doors 94 and 94a, the interior firebrick linings 95 and 95a therefor, the carrying arms 96 and 96a, heavy shafts' 91 and 9111, the counter-weight arms 98 and 98a, and counterweights 99 and 99a, both of the last two sets of parts being mounted back off to one side of the furnace proper, likewise the crank-arms I08 and |0|la, keyed to the respective shafts 91 and 91a, and the inter-connecting rod ||l|, it being noted that the single long shaft 91, which may or may peated here.

not be quite horizontal, will have mounted thereon at its extreme back end, where it will be appropriately supported by a convenient bracket 91b, carried by base 53a close to the left-hand side of shaft 52 of Figure 3, a bevel gear I02 of appropriate size, meshing directly with the left-hand side of the matching bevel gear 52a, mounted upon and keyed to shaft 52 just mentioned, this key 52b being somewhat narrower than the keyslot 520, if so preferred, so as to delay the initial start of the door-opening process until the arm 50 is well on its road toward the furnace, and close the doors promptly as it recedes, the doors 94 and 94a, being made a little heavier than the respective counterweights'99 and 99a, in order to permit this mode of operation, and all the travel speeds being relatively slow so that a lost-motion type of key will function satisfactorily without undue shock or wear.

Taking up Figure 6, referring to a straight type of furnace, new parts appearing for the first time. are as follows: high-temperature resistant rails I03, mounted on fire-brick floor of furnace, but set at a very slight angle longitudinally of the said furnace and in the plane of the floor thereof, like herring-bone gear teeth to some extent, so that the rolling ingots will not contact continuously around one limited belt on their periphery, with said rails, but will shift the line of con.- tact continuously, instead. Water-cooled ingot side-guides or stops are shown at I04. At I05 I have shown discs for controlling the forward movement of the ring-ingots, and keeping the latter squared with the desired straight line of travel through the furnace. These discs have wavy edges I06, for the purpose before cited, and are carried in suitable graphite bushed bronze or heavy-ball bearings at apex of the triangular chain-links I0'I, mounted upon pins carrying the rollers I00, riding within the heavy channels I09, suitably mounted upon the cross I-beams H0. The rolls I08 of the return portion of this chain, as shown below, ride upon the angles I I I, mounted upon the brackets II2, carried by outer wall N3 of chain-tunnel, or the central wall II I thereof. The chain I 01 and discs I05 move forward through a channel H5 in the floor of furnace, this being kept narrow. II6 shows a maintainence-tunnel, with arches II'I into chain-tunnel. A motordriven blower is indicated at B, connected by outlet tube 0 with the tunnel I I6.

In Figure '7, the intermediate connecting plain chain-links I I8 are shown, while I I9 indicates an automatically swinging entrance door; I20 and I2 I show the necessary fore-shortening of the figure to bring it within the limits of sheet, I 22 indicates an extending end of furnace where extra heat can be applied to occasional ingots requiring this, and I23 shows one form of swinging exit door.

Ah alternative form of automatic opening roof exit door is shown at I24, I24a, mounted upon the heavy shafts I25, I25a, to which suitable counterweights and driving mechanism will usually be coupled, about as already explained in connection with similar'parts 90 to IOI inclusive, in Figure 5, so that the description need not be re- In some cases there might be two or more of such double doors, successively placed along the furnace.

In connectionwith the discs I05 used for determining the speed of self-propulsion of the in gots in their down-hill course, and spacing said i ingots concomitantly, it will be noted that these ,discs do not here have to carry the weight of the ingots, the latter being fully supported by the furnace rails I03, set in the floor at a very slight angle with the side walls of furnace, as before mentioned.

Furthermore, a large fraction of each disc I05 will be observed to lie below the general floor level of the furnace, while the projecting portion occupies the coolest available portion of the furnace interior, and if found necessary, in order to better enable these discs to withstand the high temperatures encountered, the entire lower maintenance and chain-tunnel system can very readily be kept under an ounce or so of excess pressure of cooled burnt gases, or of. air, as by a small blower, for

example, so that a gentle upward flow of relatively cooler gases can be maintained thru the slot I I5, thus holding down the temperature of these discs.

The uptake flue I26 will usually be located near the ingot entering end of the furnace, while if a mutiplicity of burners I21 be utilized, these will usually, but not necessarily, be distributed more or less along the sides of furnace, so as to give a hot-gas fiownormally counter to that of the ingots.

In some cases, these burners will be grouped more closely together at points where the major part of the heating is to be done quickly.

The chain driving sprocket is shown at I28, its power-driven shaft at I29.

Referring now to Figure 8, one unit refractory is indicated at I30, its square shape being emphasized by a slightly heavier line, while depressed elements of the heavy surface fluting are indicated by the shaded area at I3I, and the'projecting elements by the clear areas I32. The position of T slot on opposite end is indicated above at I33, and in the lower half of the figure at I34, or at right angles to that above. This is in order that the same block may be used throughout, and still get the required fiuting directions.

In Figure 9, a hexagonal block system is shown, one half ofa two-part unit being emphasized as before, and the he'xagons being split so that special blocks need not be added for the side-wall fit. Part numbers are the same as for Figure 8, except with ana added, for the successive elements. This block is best when a hexagonal furnace is to be used, as successive 60 shifts are easily made in fiuting direction.

In Figure 10', I have shown an alternative diamond-shaped refractory system, using the same part numbers as in Figure 8, but with a b added, and emphasizing the shape of one unit by heavier line outline, as before.

This refractory has the great advantage of simplicity, as no fiuting need be provided on its furnace or interior face, alternate entire rows of blocks being displaced up or down as indicated,

to produce a fluting effect, which meansthat in regular continued service the older blocks can be used for the short elements as th y wear off from the tremendous heat, the longe alternate rows 12B, 128, and 12E show the hexagonal, and 13T;

13B, 138, and 13E show similar detailed views of diamond-shaped blocks, which require no further explanation here.

In utilizing a circular or hexagonalfurnace in of shape.

In Figure 14, the only new element, not previously described, is the bracket 91b, provided to support the transfer-arm end of shaft 91, extending back from the furnace door 94, and

' which bracket is in turn mounted upon the heavy cast-iron base 53a, indicated on this figure and on Figure 3. The meshing of gear I02 of Figure 5, with the gear 52a of Figure 3, is here plainly shown, whereby a properly timedinterconnection is made between transfer-arm 50 and the entrance doors 94 and 940; into furnace I.

It is believed that with the descriptions already given in connection with the several figures, the

general mode of operation of my furnaces will be self-evident without further elaboration herein, the :course of travel of the ingots into and through the one or two stages of furnaces, being obvious from Figure 4.

Certain v'ery definite advantages accrue from heating up ingots while they are under slow rotation, preferably around a generating axis, when the said ingot is more or less closely circular in its exterior outline, as this motion brings all parts of the ingot in succession, into contact with substantially the same type of hot-gas flow, and the same temperature sequences, whereas an ingot lying stationary in a furnace may have widely different flame heats presented to its' different faces, or projecting corners, or both, due to the normal burner differences, while one side of the ingot is usually more or less imbedded in the coke-breeze of floor, in customary types of soaking pit, and hence out of contact with the flame. t

The thin-walled ring" ingot, which I prefer to use, is vastly better adapted to quick and uniform heating anyway, than the customary straight types of ingot, and in my furnace this heating is further speeded up, so that very definite advantages accrue from the vastly higher tonnage output, and ultra uniformity of the heating which the furnace of my invention makes possible.

Other advantages accrue from the simple ingot handling means provided.

Since temporary interruptions may occasionally occur in the centrifugal casting unit, or its immediate-accessories, whereas it will be advantageous from the cost standpoint to keep the .rolling mill in continuous operation, my provision of twin-furnaces capable of taking coldingots from the storage tracks, or red-hot ingots just out of the stripper, in any succession or proportions required, without interrupting the normal regular sequence of delivery to the mill,

results in still further advantages accruing from the use of my furnace system.

Additional advantages result from my provision of means for rolling the ingots over and over as they progress through the furnace, over angularly laid rails, or over rotating-rolls which have a staggered tread, whereby cold-streaks or spots over the ingot are largely avoided.

The rolling progression further obviates the deep scoring. or galling often produced in the ingot, when the latter is advanced by forcible skidding along the usual floor rails, or skids,

while its surfaces are soft from the heat.

The speed of movement of my ingot-progress ing means is such as to carry the ingot several times around my annular type of furnace during the course of its normal heating up, so that every ingot is presented many times to the discharge position before its final removal. v 5

This leads at once to the further great advan tage that my furnace is 100% selective, since any ingot can be brought up to the discharge posi tion, and a new one put in the furnace to replace it, irrespective of its position on the annularl0 carriage, and without in the least disturbing any other ingot on the platform. Any ingot which happens to be a little slow in heating up to the required pyrometer temperature, can be allowed to simply remain for another circuit or two around the furnace, until it is up to the required heat, yet without disturbing the normal ingress, or egress, of any other ingot in the series.

In Figure 3, I have shown a discharging type of transfer-arm only, but with self-evident modifications 'it may be readily converted to a charging arm, or into an intra-furnace type of. transfer-arm, as required. Of course, all its motions may be under simple manual control, without any automatic interlock features, but I have illustrated what I consider to represent a preferred form.

Other advantages of my furnace system will be evident to anyone skilled in the art.

While I have herein illustrated and described one preferred embodiment of the apparatus constituting my invention, together with two alternative forms of the furnace proper, it will be understood that still further moderate changes in the construction, or arrangement of the parts,

may be made without departing either from the spirit of my invention or the scope of my broader claims.

I claim;

1. An apparatus for heating ring-ingots, com- 40 prising a substantially annular furnace enclosure, a substantially circular moving-side-walk mounted horizontally in the floor of said furnace enclosure, a plurality of power-driven ingot-carrying means each combined with an ingot'rotating means and an ingot spacing device all in one and all mounted operatively on said moving-sidewalk and geared so as to function as the latter progresses, and a power-drive applied to progress said moving-side-walk around said furnace enclosure, said ingot spacing device being operative to hold successive hot ingots out of contact with each other during rotation, to obviate surface galling thereof.

2. An apparatus for heating cylindrical ingots, comprising a substantially circular furnace, a substantially circular moving-platform device mounted for circular advancement around said furnace in the fioor thereof, an ingot-rotating mechanism mounted operatively above said de- 0 vice, a power-drive for said ingot-rotating mechanism, an intermittently operable power-drive applied to said device, a stop element and an indexing element attached to said device to operate said stop element and connected with the last mentioned power-drive to determine the position of stopping of said device.

3. An apparatus for heating cylindrical ingots, comprising a substantially annular furnace enclosure, an annular. moving side-walk type'of ingot-transport means mounted substantially horizontally in the floor of said enclosure, 2, plurality of combined rotating, supporting, and spacing means for said ingots and all mounted in succession upon said-ingot-transport means,

power means applied to progress the latter means around said enclosure and to concomitantly rotate the said combined means, and an ingot-centering means mounted adjacent said irmot-transport means to align said ingots during transport.

4. An apparatus for heating cylindrical ingots, comprising a substantially annular furnace enclosure, a moving-side-walk device operatively mounted therein, a power drive applied to said device, a plurality of ingot supporting means mounted in succession around said device and operative also to rotate and to space said ingots apart, and a gearing mechanism connecting with 4 said means to rotate the "same as said device is advanced by said power drive.

- 5. A furnace for heating ingots, comprising a substantially circular enclosure, a moving platform device mounted for advance horizontally around said enclosure, a power drive applied to said device, an indexing mechanism providing for definite successive stop positions of said device in its advance around said enclosure, through connections with said power drive, and a power means applicable to lift one of said ingots at a stop position of said device and transfer said one ingot to a point outside said furnace, or into said furnace, as desired.

6. A furnace for heating ingots, comprising a substantially circular enclosure, a moving platform device mounted for horizontal advance around said enclosure, a power drive applied to said device, an indexing mechanism connectible to said power drive to determine the positions of successive stops of said device, and a man-' ually operable selector means connected with said indexing mechanism to provide for running-past successive stops as desired, whenever no ingot transfers are to be made to or from said furnace.

7. A furnace for heating ingots, comprising an enclosure lined with refractory blocks, those on the ceiling forming projecting herringbone teeth with intermediate channels, all converging at an angle toward centre-line of said enclosure, for hot-gas directing purposes, and a moving-sidewalk device mounted for ingot carrying purposes in the floor of said enclosure.

9. In an ingot heating system, parts compris ing a substantially annular furnace enclosure,

a moving side-walk type of ingot transport means mounted operatively in the floor of said enclosure and arranged for substantially horizontal advance within the same, a power-drive for said means, an index means connected to said powerdrive to determine stop positions of said transport means, an ingot transfer-arm mounted adjacent to said enclosure and arranged to lift said ingot therefrom at a stop position of said transport means, and a second ingot transport means operable outside said enclosure and positionable to receive an ingot from said transfer-arm at outer end of the swing thereof.

10. A claim as in 6 but in which the said furnace enclosure is characterized as having ingot doors in the ceiling thereof, operable for ingress or egress of an ingot at any stop position of said moving platform, device.

11. An apparatus for heating circular ingots, comprising a substantially circular furnace enclosure, a moving side-walk device mounted about horizontally in the fioor of said enclosure, a power-drive arranged to advance said device around said enclosure, a limit switch connectible to terminate the operation of said power-drive when required, an indexing element mounted to contact with portions of said device so as to function said limit-switch at definite successive positions in the travel of said device, and a manually operable switch connected to maintain said power-drive in continuous operation independent of the action of said limiti-switch, when desired, as when no ingots are being withdrawn.

12. An apparatus for heating substantially cylindrical ingots, comprising a substantially circular furnace enclosure, a plurality of rotatable ingot supports, a moving-side-walk device mounted for advance around said enclosure and providing a mounting for said supports which are spaced uniformly therearound, power means to advance said device, gearing providing concomitant rotation of said ingot supports during said advance, and "an ingot positioning device operable to substantially centre said ingot on said .supports duri'ngthe advance thereof.

13. A claim as in 12 in which said furnace enclosure is characterized by the provision of a maintenance tunnel under said moving-side-walk device.

14. A claim as in 12 in which said furnace enclosure is characterized by the addition of a maintenance tunnel under said moving-side-walk device, said :tunnel providing a channel for the supply of cool air to the operative mechanism of said device. 1

15. The method of heating substantially cylin- J drical ingots; which comprises the steps of continuous slow rotation of said ingots to give uniformity of heating, the directing repeatedly of considerable portions of the heating gases toward the-normally under-heated central sections of said ingots for the same reason, the continued separation of said ingots both from each other and from the floor in order to obviate the usual galling up of the outside surfaces as where such contacting is allowed, and the prevention of circular cold streaks around said ingots by the utilization of non-regular lines of contact with the hot metal thereof by the supporting and rotating means.

JAMES L. ADAMS, JR.

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