US2597811A - Metal pouring apparatus for feeding molten metal into centrifugal molds - Google Patents

Description

y 20, 1952 J. J. NOLAN, JR 2,597,811 METAL POURING APPARATUS FOR FEEDING MOLTEN METAL INTO CENTRIFUGAL MQLDS Filed March 18, 1949 5 Sheds-Sheet l INVENTOR JOH/VJ/VOLANIR.

RNEY

Filed March 18, 1949 May 20, 1952 J. J. NOLAN, JR 2,597,811

METAL POURING APPARATUS FOR FEEDING MOLTEN METAL INTO CENTRIFUGAL MOLDS 5 Sheets-Sheet 2 IHHh,

INVENTOR JOHN J NOLA N .75.

y 1952 J. J..NOLAN, JR 2,597,811

METAL POURING APPARATUS FOR FEEDING MOLTEN METAL INTO CENTRIFUGAL MOLDS Filed March 18, 1949 5.SheetsSheet 3 INVENTOR go/41v I NOLAN 37?.

' ATT RNEY May 20, 1952 J. J. NQLAN,.JR

METAL. POURING APPARATUS FOR FEEDING MOLTEN METAL INTO CENTRIFUGAL MOLDS 5 Sh'eetsSheet v4 Filed March 18, 1949 INVEN'i'OR Ag JUHN .INoL

BY M RNEY y- 1952 J. J. NOLAN, JR 2,597,811

METAL POURING APPARATUS FOR FEEDING MOLTEN METAL INTO CENTRIFUGAL. MOLDS Filed March 18, 1949 5 Sheets-Sheet 5 INVENTOR BYJ'OHN .I/VOL/IN 1/? A RNEY Patented May 20, 1952 r UNITED STATES PATENT OFFICE v I I POURING FOR FEEDING I MOLTEN MOLDS METAL INTO CENTRIFUGAL John J. Nolan, Jr., New York, N. Y., assignor to The Central Foundry Company, New York, N. Y., a corporation of Maine 1 Application March 18, 1949 Serial No. 82,166

molten metal into the mold, (1)-rapidly, (2) to distribute the metal uniformly over the rotating surfaceof the mold, (3) Without dangerto the foundryman, and (4) so as to produce a good casting, free of laps, blow holes and other sur--v face defects. The general problem is concerned withother objectives as well, but insofar as related to metalpouringthe leading object hasbeen to obtain rapid and uniform. distribution of the metal. The problem has been a particularly troublesome one where the metal is cast into unlined or uninsulated metal moldsso-called chill molds or permanent molds, or into molds having very thin coatings which arenot truly insulating coatings and which have little insulatingyeffect so that the metal is cooled rapidly and approaches its solidus within a few seconds or so, In this kind of centrifugal casting operation, pipe of the desired characteristics andunifcrmity can be produced only if advanced foundry techniques are utilized, and considerable skill employed. Even so, trouble is frequently experienced in the pouring of the metal. If all other conditions be perfect and yet the pouring is not done in just the right manner, satisfactory pipe will not be produced, and the percentage of rejects goesup. I j

Inventors in'this art have concerned themselves, heretofore, with elaborate pouring trough 1 arrangements in which the metal is poured from a series "of lips, or weirs, spaced throughout the length of the mold, or with troughs which are advanced into the mold to begin the pouring operation at the far end and which are then withdrawn as the metal is being poured, or'with apparatus designed theoretically to lay the metal down the aim was to distribute the metal uniformly over the surface of the mold from end to 'end within the relatively short time of approximately 3 seconds (in the case of a 70 or 90 pound pipe). With these and other objects in mind, and after much 3 Work and experimentation, I hit upon an idea which seemed to work out much betterthan anything I had known about or tried before. With reference to the accompanying drawings, I shall now describe what I consider to be the best form of apparatus utilizing my invention.

Fig. 1 is a side elevational view of my appa-.

ratus as designed for use in a pipe foundry.

Fig. 2 is a top plan view of the same apparatus. Fig. 3 is a rear elevational view of the same apparatus, looking at the back of the pouring ladle.

Fig. 4 is an enlarged side elevational view of the pouring ladle and its associated hydraulic con-' trol mechanism, with a schematic showing of its operating characteristics.

Fig. 4a is a diagram based on a schematic vertical cross-section of the pouring ladle.

Fig. 5 is a detail view showing, in vertical cross-section, the lip of the pouring ladle and the adjacent trough, or boot.

, Figs. 6 to 9, inclusive, are detail vertical crosssectional views of the control valve of the hydraulic mechanism, showing several selected positions during a pouring cycle.

Referring to Figs. 1 to 3, my preferred form ment a ladle l0 supported for tilting movement, a fluid pressure operating device H for producing tilting movement of the ladle to discharge molten metal therefrom, and an hydraulic mechanism indicated generally by reference numeral IL, for variably controlling the speed of said tilting movement, the hydraulic mechanism comprising a variable orifice valve l3 operably connected to the ladle to as by means of a linkage indicated generally by reference numeral It, whereby the operating position of the valve changes in response to successive changes in the position of the ladle as it tilts during the metal pouring operation. As the ladle tilts, the molten metal therein is discharged into. a suitable pouring trough 'or boot it which is arranged to feed the metal into the end of a centrifugal mold It. The mold is mounted for rotation about a substantially horizontal axis, and for this purposeis arranged in a suitable centrifugal casting machine. As such machines are well known in the centrifugal'casting art generally, and in the art ofcentrifugal casting of metal pipe and similar objects in particular, and inasmuch as the machine itself forms no part of the present invention, it will not be described in detail here. However, in order that the general arrangement of my apparatus in relation to the mold and to the centrifugal machine may be more fully understood, I have included by way of example a par* of the roller shafts are driven from a suitable.

power source.

In my preferred construction the metal pouring apparatus is mounted on a carriage 22 for movement toward and away from the mold so that the end of trough l5 can be run into the end of mold l6 (or into any attachment thereto) during the metal feedingoperation. This is the positionof the trough and its associatedmechanism as shown in Figs. 1 and 2. The carriage has fianged wheels 23 running on tracks 24 mounted on a suitable frame indicated generally by reference numeral 25, as by means of angle irons 25. If desired a vertical adjustment maybe provided to assist in aligning thepouring mechanism with the mold. For this purpose I have shown, in angle iron '26, pairs of-vertical slots 21 through which extend clamping screws 28 with threaded engagement in the frame. Adjusting screws 25 '(Fig. 3) also have threaded engagement with the frame and bear on the under side of the horizontal'fianges of angle irons 26. When clamping screws 28 are loosened, adjustment of screws 29 raises or lowers the tracks 24-to bring the carriage and its associated pouring mechanism into the desired alignment with mold 5, after which clamping screws 28 may again be tightened. Movement of the carriage is accomplished by fluid pressure means such as provided by cylinder 33 fixed to the frame 25 as by means of connecting pin 3! in which operates a piston, the piston rod 32 being connected to a bracket 33 fixed to carriage 22. Thepiston isdouble acting, and through the'operation of a suitablercontrol valve for introduction of fiuid to one end or the other of the cylinder, carriage 22 is caused to reciprocate as may be desired. Thus the carriage can be moved to the left as viewed in Figs. 1 and 2 to withdraw pouring trough l5 from" the end of mold l6 after the completion of the casting operation. This permits the mold to be removed from the machine without interference with the trough. Conversely; after the mold is placed in the machine and is ready for pouring, the carriage will bemoved to the right to bring the trough i5 into the position shown in the drawmgs.

The side frames of carriage '22 have at the forward end of the carriagesuitable means for supporting the ladle NJ for tilting movement. For example, in the construction illustrated, a pair of vertical plates 34 provide bearings for trunnions 35 fixed to a U-shaped frame 36 on which ladle I0 is supported with its laterallyj extending flanges 3'? restingv on top thereof. The ladle is held in position in frame 36 by means of clamping fingers 33 attached to laterally extending arms 33 fixed to frame 33. These arms have rounded extensions 483 for pivotal engagement by piston rod brackets 4L. One of these brackets is fixed to the piston rod of an air cylinder 1 I pivotaxle shaft pass through a bearing opening in the end of the cylinder. The other bracket 4| is fixed to the piston rod 4| of an hydraulic cylinder 43 pivotally secured to the carriage at the opposite side of the ladle from air cylinder ll. Air connections 44, 45 lead, through suitable control'valves,-,to' a source of air. pressure: As air at elevated pressure is admitted to-the' lower end of cylinder l I, the piston is raised, tilting frame 36, and with it ladle Hl, around the axis of trunnions 35.

Hydraulic cylinder '43 forms a part of the hydraulic mechanism l2 to which reference has been made before. This mechanism comprises, in addition to'control-cylinder 43 and the piston operably connected to.v the ladle as described, for

movement therewith relative to the cylinder dur-' ing' tilting of the ladle, a conduit 46 connecting opposite ends of the cylinder as shown in Fig. 1, through which conduit liquid is required to fiow by movement of the piston as the ladle tilts duringthe metalpouring operation, a variable orifice valve I3 in said conduit, and an operatingarm- 41 for said valve movable in response to change in the position of the ladle to vary the. rate of flow of liquid through valve [3 andthereby producea correspondingv variation in the speed of tilting of the ladle. Movement of operating arm 47 is produced by the linkage l4previously mentioned. This linkage comprises astrap 48'pivotally secured .to operating arm 4! of the valve as by means of stripper bolt 43' passing, through a selected one of a series of apertures. 50 and through a slot 5| in the valve arm. The upper end of strap 48' is pivotally secured in a similar manner to an arm 52 fixed withrespect to the ladle as by attachment to arm '39 of the ladle frame 36.

The hydraulic mechanism may, if desired, further include a by-pa-ss conduit 53 through which liquid can flow when theladl'e is beingreturned to its original position. This by-pass conduit has a check .valve' 54 therein to limit liquid flow through the by-pass during the metal pouring bottom of the cylinder. In this part of the operation the liquid cannot flow through the by-pass conduit 53" because of the operation of check valve 54. However when the air pressure is released to lower the ladle to its original position for the succeeding pouring operation, liquid is free to flow from the bottom of cylinder 43 through check valve 54 and by-pass conduit 53 back into the top of the cylinder for quick return action of the ladle. During this return action some of the liquid may also flow through valve 13 and conduit 46, but the by-pass serves to speed up the operation. A water line connection 55 feeding into by-pass conduit 53 provides means for intro-. ducing a'dditionalwater into thehydraulicsystem wheneverneeded. A suitable control. valve 56 is provided for this. purpose.

Pouring 'trough;l5 is fixed ,to the carriage in position to'receive metal .dischargedffrom the lip 57 of ladle it. As shown, cars 58 projecting.lat-. erally from the trough rest on top of a U.-shaped supporting member 59 fixed to vertical'plates 34 of the carriage, the trough being clamped in place by means of suitable fingers 65 or otherwise...

From the foregoing description of the hydraulic control mechanism, it will be understood that the hydraulic control cylinder 43' is operated by the ladle, and that'the speedcontrol valve. l3lfor the control cylinder. also is: operated by the ladle. This means that the size of'the orifice in valve l3 changes progressively during the pouring of the metal from the ladle, thus imposing a varying resistance to the tilting of the ladle. Inasmuch as the ladle is being operated by a fluid pressure device which exerts a substantially constant torque about the tilting axis, the tilting action will be slowed down or speeded up as pouring progresses, depending upon the adjustment of the linkage between the valve and the ladle. In general, for the casting of pipe of uniform wall thickness longitudinally, I have found that improved results are obtained by slowing up the metal pouring operation as it proceeds. If the wall thickness is to vary over the length of the pipe, the linkage can be adjusted so as to produce the desired rate-of pour at all times during the pouring cycle.

My apparatus is designed particularly for extremely rapid operation such that the entire pouring cycle may consume as little as 0.06 minute or less-that is, on the order of 3.6 seconds. In casting a 63 pound soil pipe 4 inches in diameter with a wall thickness of inch, I have found that excellent results are obtained if during the first third of the pouring cycle, in respect of time, approximately one-half of the metal in the ladle is poured, with approximately one-third of the total metal being poured in the next one-third, and the remaining one-sixth being poured in the last third of the cycle. I wish it to be distinctly understood that these proportions will vary in accordance with the article to be produced, but in general improved results are obtained if the rate of pouring progressively decreases during pouring, and the apparatus I have described can be adjusted through changing the selected positions of the valve linkage so as to produce the best operation for any particular set of conditions to be met.

In one method of operation of the apparatus, the linkage will be adjusted to the position shown in Fig. 1, which is drawn approximately to scale, and which shows my preferred adjustment for the casting of 63 pound double hub cast iron soil pipe 4 inches in diameter with a wall thickness of inch in an uninsulated metal mold in accordance with the casting method described in my prior United States Patent No. 2,378,723.

The operation of the apparatus will now be described with reference to schematic views Figs. 4 and 4a of the drawings, and to Figs. 6 to 9, detail vertical cross-sectional views of the control valve of the hydraulic mechanism shown in several selected positions during a pouring cycle. We will assume a pouring cycle of 7 of a minute; The position of the ladle and associated mechanism at the beginning of the pouring operation is shown by the full lines in Fig. 4, the level of the metal in the ladle being as indicated in Fig. 4a. The ladle here shown has vertical side walls 6!, a flat bottom wall 62 and an arcuate end wall 63, the latter being formed on a curve which has as its center approximately the center of the tilting axis, although this may be varied slightly depending upon the curvature of the lip 51 of the ladle. With this form of ladle, approximately equal increments of metal will be discharged for equal increments of tilting.

of a minute after the beginning of pouring (initiated by turning the control valve of operating air cylinder I I), arms 49 will be in the position shown at 46 in Fig. 4. Through arm 52 and connecting strap 48, the operating arm 41 of control valve I3 will have been moved to the position shown at 41 At this point the axis of the conduit 46, i. e. the axis of valve [3, will have been changed slightly due to the change in position of cylinder 43 (to which the conduit is fixed) in following the movement of the ladle about its tilting axis. This change in the valve axis can be seen by comparing the detail views Figs. 6 and "I, Fig. 6 showing the position of the valve and its operating arm 41 at the start of the operation, and'Fig. '7 showing the relative positions of these elements W of a minute later, that is, after the ladle has tilted through angle A (Fig. 4). During this interval of time, the quantity of metal discharged from the ladle is indicated diagrammatically in Fig. 40!. by the area cross-hatched to represent the color brown, and identified as A. At this point the level of the metal remaining in the ladle is indicated at a. Also at this point the extent to which the valve l3 has been closed is shown in Fig. 7.

Taking the position of the center line of operating arm 41 as indicated in Fig. 6, we see that it is disposed at an angle alpha with respect to the center-line of the valve. This is the zero angle. of a minute later this angle has become beta (Fig. '7). The operating arm 41 therefore has been moved through an angle with respect to the valve of beta minus alpha which, with the settings adopted for the purposes of this specific example, is equal to approximately 33 30'. This closes the valve about one-third of the way from its fully open position to its fully closed position.

During the next of a minute the ladle is tilted through an additional angle B with the ladle arms 40 brought to the position indicated at 40 and the valve operating arm into the position indicated at 41 after rotation through an angle equal to gamma, Fig. 8, minus beta, Fig. '7, or approximately 21 15'. During this interval of time the additional quantity of metal which has been discharged from the ladle is indicated diagrammatically in Fig. 4a by the portion crosshatched to represent the color orange, and identified as B, bringing the level of the metal in the ladle to the line b.

During the final A of a minute the ladle is tilted through an additional angle C with the ladle arms 40 brought to the position indicated at 40 and the valve operating arm into the position indicated at 41 after rotation through an angle equal to delta, Fig. 9, minus gamma, Fig. 8, or approximately 8 15. During this interval of time substantially all of the metal remaining in the ladle will have been discharged, that is, the quantity indicated diagrammatically in Fig. 4a by the unhatched portion identified as C, bringing the surface 0 of bottom 62 of the ladle into a horizontal position. At this point the valve I3 will be approximately two-thirds closed. The fully closed position of the valve is indicated in Fig. 9 by the line bearing the legend to this effect,

and which represents the center line of the valve arm 41.

The entire pouring operation is performed, insofar as the foundryman is concerned, by simply opening the valve of the air operating cylinder; that is to say, the operation is fully automatic. Thus it will be seen that my invention comprises metal pouring apparatus in which the control of the speed of tilting of a ladle is determined by the position of the ladle itself, making the ladleself-regulating in accordance with a predetermined adjustment of the apparatus. More specifically, my apparatus comprises a control cylinder for a ladle supported for tilting movement and a piston in the control cylinder preferably connected "to the vladle :for movement therewith relative to thecylinder during tilting of the'ladle, a conduit connecting opposite ends of the'cylinder and through which liquid is required to flow "by the movement of the piston .as'the ladle tilts during the metal pouring operation, a valve in said conduit, and an operating member for said valve movable in response to change .in the position of the ladle to vary the rate of flow of-liquid through said valve and thereby produce a corresponding variation in the speed of tilting 'of the ladle.

The apparatus distributes the metal over the rotatingsurface of themold in a substantially uniform layer and with extreme rapidity. This 'is'accomplished Without requiring the use of a movable pouring trough. That is, the arrangement is one "whichpermits introduction of the metal to the mold from one end thereof.

Irecognize that-certain changes-might be made in the operative connection between the control valve and the ladle, or in the shape of the ladle, etc.,and it should be understood that the terms and expressions which Ihave employed are used in adescriptive and not a limiting sense, and that I have no intention "of excluding such equivalents of theinvention described, orof portions thereof,

as fall within the 'purviewof the claims.

I claim:

1. :Metalpouring apparatus for feeding molten metal in'to centrifugal molds in the casting of pipe and the like, which comprisesa ladle supported for tilting movement about a substantially horizontal axis for the discharging "of molten metal therefrom, a member on which the tilting ladle is mounted, a fluid pressure operating device comprising a piston element and a cylinder element, means connecting oneofsaid elements to said member, means connecting the other of said' elements to the ladle, and an hydraulic 'through'whichliquid'is required to flow-by relative movement'betw'een the piston'a'nd cylinder thereof as the ladle tilts during the metal pouring operation,-a valve in said conduit, an operating 'memberior saidvalve, and'a linkage 'conmeeting said operating member to the ladle for moving said valve in response 'to change in posi- :8 tion ofthe ladle-to vary the rate of flow of liquid through said valve and thereby produce a corresponding variation in the speedof tilting of the ladle.

2. Metal pouring apparatus constructed in accordance with claim 1, in'which said valve operating member extends downwardly from the valve so that the rate of pouringprogressively decreases during the pouring operation.

3. Apparatus constructed in accordance with claim 1, in which-said hydraulic mechanism further includes a by-pass conduit connecting opposite elements-of the cylinder and through which liquid can flow when the ladle is being returned to its original position, said by-pass conduit having a check valve therein to limit liquid flow through the by-pass during-the metal pouring operation.

4. Centrifugal casting apparatus comprising .a rotary mold,-a trough for directing molten 'metal into one end of said mold and terminating near said end, a tiltable ladle for pouring molten metal into said trough, a member on which said ladle is mounted, a fluid-pressure operating device for applying substantially constant torque to said ladle for tilting the latter topour said metal into said trough, said operating-device comprising "a piston element and a cylinder element, means connecting one of said elements to said member, means connecting the other of said elements to said ladle, means for maintaining said trough stationary during pouring of said metal into the mold, an hydraulic mechanism comprising a piston element and a cylinder element, means connecting one of said'last named elements to said member, means connecting the other of said last named elements to said ladle, means comprising a valve for controlling passage of liquid from one portion to the other of the last-mentioned cylindenand linkage means connecting said valve to said ladle to operate .said valve for varying the speed at which said ladle is tilted by'said operating device in response to changes in the positionof said ladle during tilting thereof.

JOHN J. NOLAN, JR.

REFERENCES CITED The followingreferences are of record in the 'file' of this patent:

UNITED STATES PATENTS Number Name Date 1,497,091 Dahill June 10, 1924-. 1,737,459 Hurst et all. Nov. 26, 1929 2,088,546 Camerota July 27, 1937

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