US1736424A - Centrifugal casting of hollow bodies of metal - Google Patents

Description

' Nov. 19,1929. J. QBELL" CEN'IRIFUGAL CASTING 0F HOLLOW BODIES OF METAL s Sheets-Sheet 1 Filed July 7, 1925 Inventor.

J C BELL CENTRIFUGAL' CASTING OF HOLLOW BODIES 'oF- METAL 3 Sheets-Sheet 2 Filed dl 7,1925

J. c. BELL .Nov'. 19, 1929.

' CENTRIFUGAL CASTING oF' HOLLOW aonrEs 0F METAL Filed 'July 7. 1925 5 sn etswnet 3 r Patented Nov. 19, 1929 UNITED STATES PATENT OFFICE JOHN CHAPMAN BELL, OF SHEFFIELD, ENGLAND, ASSIGNOR, BY MESNE ASSIGNMENTS.

T0 CENTRIFUGAL PIPE CORPORATION, OF WILMINGTON, DELAWARE, A CORPORA- TION OF DELAWARE CENTRIFUGAL CASTING OF HOLLOW BODIES OF METAL Application filed. July 7, 1925, Serial No, 41,970, and in Great Britain- July 3, 1924.

This invention relates to the centrifugal successively deposited, spirally related, subdi-' visions, the metal being caused to flow in a limited sheet. In practice it has been found I that this process cannot be employed for the production of bodies having thick walls, and that the subdivisions which were first deposited have solidified by the time the spout is at the other end of the mould.

It is also known to pour molten metal in a plurality of jets on to'the bottom of a rotary mould, with relative reciprocatory movement between the pouring conduits and the mould longitudinally of the latter. In accordance with the present invention molten metal is projected on to or towards the descending wall of an uncooled rotary mould in a plurality of jets from points at a substantially constant distance from said wall or from the inner surface of metal deposited thereon while relative reciprocatory movement between the jet apparatus and the mould takes place longitudinally of the latter, the metal being caused to spread out to form a continuous homogeneous layer within the mould, the molten metal from adjacent jets merging together laterally and the molten metal projected during each stroke of the reciprocatory movement (after the first) merging with the-metal projected during the preceding stroke, which metal remains molten at least until metalhas been projected during the following stroke. By stroke I mean the forward or backward movement of the tubular spout from which the plurality of jets issue, which spout and the means by which it is moved will be later described.

By the word uncooled it is intended to be understood that no measures are taken to abstract heat from the mould, which on the contrary must retain as much heat from the molten metal as will suffice to maintain the inner periphery of the deposited metal in a molten condition. The apparatus for carrying out the improved process thus diflers from that previously known, in that the mould is not cooled during the casting operation, the metal is conveyed to the mould by means of a tubular spout under a constant head of pressure greater than that which could be obtained if an open-topped spout or trough were employed; and means are provided both for relative reciprocation between the mould and spout longitudinally of the 'mould, and for movement of the spout transversely of the mould during the casting operation.

One form of this invention is illustrated by the accompanying drawings, wherein Figure 1 is a sectional side elevation, Figure 2 a partly sectional plan, Figure 3 a crosssection on the line 3-3, Figure 1 and Fig. 4 is a sectional view on line 4-4 of Fig. 1. As shown, an open-ended cylindrical steel mould a is rotatably supported on roller or like bearings b and is coupled by a dog or like clutch c with a shaft d on which is a pinion e driven by a chain f from a pinion g on the spindle h of an electro-motor j. The free ends of the arms of the clutch c extend,

parallel with the axis of rotation, into recesses in the adjacent end of the mould a so that the coupling is unaffected by either longitudinal or radial expansion of said mould. Within each end of the mould a is an inwardly-extending circumferential flange k the inner periphery of which is feathered as at m,and projecting into said mould from that end thereof remote from the electro-motor j, and below the level of, and parallel with, the axis of .said mould, is a tubular spout n, lined, as at 0, Figures 2 and 3, with highly refractory material, such as magnesite, closed at its one end, as at p, Figure 2, and having a similarly lined funnel or receiver 9 at its other end, and furnished at one side with a longitudinally spaced series of nozzles r The spout n V is mounted on a carriage 8 adapted to be trio or other suitable winch 3 Further, the

spout n is movable on the carriage s transversely thereof by being mounted on a carriage S supported by wheels t -on tracks a supported on carriage S. 2 is an hydraulic cylinder for moving carriage 8 This transverse movement is given to the spout so that it may be maintained at a substantially constant distance from the inner periphery of the mould a or of the metal therein, as the case may be, during the casting operation. In some cases it may be desirable to provide means such as screw-jacks for adjusting the spout n vertically according to the fluidity, analysis, temperature or other conditions affecting the molten metal. cent to the funnel or receiver 9 is a pivoted ladle 11 adapted to be rocked about its horizontal axis, e. g. by means of an hydraulic cylinder 11*, the valves of which are electrically controlled, said ladle 11 at its delivery end 12 extending over the receiver g as shown in Figure 2 so as to be adapted to.

deliver molten metal thereto. The ladle 11 is provided with a lip 13 at that end remote from its delivery end 12 so that when in its inoperative position (i. e. not discharging into the receiver q) any molten metal which may be fed to the ladle 11 will overflow without passing into the receiver 9. By these means it is possible, at starting, to discharge molten metal from a ladle .(not shown) into the ladle 11 and allow it to escape until :the slag has passed away and there is a steady flow of molten metal; whereupon the ladle 11 maybe tilted to direct the flow into the receiver 9, which latter is-of-such length that molten metal will flow thereto from vthe ladle 11, while the receiver g is reciprocated as one with the spout 71. On the one hand a.

substantially constant head of pressure may be maintained in the spout n by eeping the receiver 9 full, and on the other h ndvthe flow of metal may be cut oil readily by merely tilting back the ladle 11. The stroke of the spout n will depend upon diflerent circumstances such as thevpitch of its nozzles r and the fluidity of the molten metal, it being desirable to avoid splashing, to ensure even distribution of the molten metal and to maintain the greatest possible uniformity in temptrature of-the mould a and the metal, and it may even be desirable so to vary the cross-sectional areas of the nozzles r or Disposed adja-- the cross-sectional area of the spout n as to ensure a substantially uniform flow from the several nozzles r although such substantially uniform flow could be obtained by making the cross-sectional area of the spout n1 large as compared with that of each nozz e 7'.

Before use, the mould a and spout n are preferably heated by gas jets or like means (not shown) to about 100 to 120 F and a steady flow of molten metal having been obtained from the ladle to the ladle 11, the latter is tilted to direct said flow into the receiver g and thence through the reciprocating spout n to the nozzles 1" whence it is sprayed into the mould a. The molten metal from the jets 1' during the first stroke of the spout n, remains molten on coming into contact with the mould a, and under centrifugal action is caused to spread out to flood the wall of the mould with a continuous homogeneous layer, the molten metal from adjacent jets mergin together laterally. On the next stroke ol the spout n the molten metal from the jets, not only merges together laterally as just mentioned but merges also with the molten metal already in the mould a, and so on, the mould retaining as much heat from the molten metal as will suffice to maintain the inner periphery of the deposited metal in a molten condition. lVhen the hollow body has been thus formed with a wall of the required thickness, the ladle 11 is tilted back, the spout n is withdrawn, by disconnecting it from the ram 4) of the hydraulic cylinder, w, and connecting it with the cable at driven by the winch 3 and rotation of the mould a is continued until solidification of the cast metal has taken lace.

After solidification and cooling of the cast body have taken place it may be withdawn from the mould a after the flange is has been removed from that end of the mould a remote from the clutch c, whereupon the body may be supported, as it is withdrawn, upon rollers 14 i The mould a may be positioned upon the rollers b by means of an external flange or rib 15 .and pairs of thrust rollers 16, as shown, or other means may be employed, such for instance as grooved peripheral tracks for the rollers b while straddling frames such as 17 17 carrying overhead rollers such as 18, 18 may be provided as a measure of safety to keep the mould a from leavin the rollers b j in some cases the spout 11. may pass right through the mould a and its closed end may be supported during the reciprocatory movement on roller or like bearings, so as to relieve said spout of strain while it is in a highly heated condition.

The speed of rotation of the mould a is dependent upon the diameter of the body to be cast and upon the rate of flow of the molten metal, e. it has been found that a inch internal iameter mould should be rotated at about 220 revolutions per minute when the molten metal is delivered at the rate of 7 8 cwts., in 102' seconds through five 1 4 inch nozzles.

I claim- 1. The improved process for the centrifugal casting of hollow bodies of metal which consists in depositing molten metal in a rotary mold in a plurality of jets delivered through nozzles leading from a tubularconduit while maintaining a constant reciproca- I tory movement between the mold and conduit the mold longitudinally of the mold, thereby causing the metal tdspread out so as to form a continuous homogeneouslayer within the mold, the arrangement of the nozzles and the rate of reciprocation being such that the molten metal from adjacent nozzles will merge together laterally, while the temperature of the mold, its speed of rotation andspeed of relative reciprocation between, the mold and nozzles are such that molten metal injected "tory movement will merge with, the molten 40,

during successive strokes of the reciprocametal injected duringv the. previous reciprocatory moyement,the metal delivered during each reciprocation remaining molten at least "until the metal delivered during the succeeding reciprocation has b'eendelivered to the mold.

3. In the im'provedprocess of claim '2, the

further step which consists in delivering the molten metal to' the mold..under a constant head of pressure.

4. An improved process for thejcentrifugal casting of hollow bodies of metal which consists in depositing molten vmetal on the descending wall of an runcooled rotary mold by projecting it ina plurality of jets from points maintained at a substantially constant distance from the surface of the metal deposited on said wall, while maintaining a relative reciprocatory movement between J the jetsand the mold, longitudinallyof the latter, thereby causing the metal to spread out;

so as to form a continuous homogeneous layer within the mold, the'arrangement of the ets being suchthat the molten metal from adja-' cent jets is adapted to merge together laterally, while the, temperature of the mold, its

rotation and relative reciprocation are such that molten metal projected during succes sive strokes of the reciprocatory; movement are adapted to merge with the metal projected during. the preceding stroke, the metal delivered ateach stroke remaining molten at least until metal has been projected during the following stroke.

c 5. An improved process for'the centrifugal casting of hollow bodies of metal, as

claimed in claim 4, according to which themolt'en metal to 'be projectedis fed under a constant head of ressure. I 6. Apparatus or the casting of 110110 bodies of metal comprising a rotary mold, means for rotating said mold, means for injecting molten rnetal by projecting it'into the mold through a tubular conduit having a plurality of nozzles, means for eiiecting a relative longitudinal'reciprocatory movement etween the tubular conduit and the mold and means for -feeding molten metal to the tubular conduit under a constant head of pressure. a

7. Apparatus for the casting of hollow bodies of metal comprising a rotary mold,

tive longitudinal reciprocatory movement between the t-ubular conduit and the mold and means for feeding molten metal to the tubular conduit under a constant head of pressure comprising a funnel like receiver connected to the tubular conduit and a ladle pivoted on a horizontal axis above the level of said receiver.

8. Apparatus for the casting of hollow bodies of metal comprising a rotary mold, means, for rotating saidmold, means for injecting molten metal-by projecting it into the mold through a tubular conduit having aplurality of nozzles, means for effecting a relative longitudinal reciprocatory movement between the tubular conduit and the mold'and means for feeding molten metal to the tubular conduit under aconstant head of pressure comprising a funnel like receiver connected to the tubular conduit and a ladle pivoted on a horizontal axis above the level of said receiver, said ladle being formed withan outlet at one, end for delivering molted metal to the receiver and with an overflow lip at its other end.

' 6, wherein the free endslof the arms of a dog 9. Apparatus for the centrifugal casting of Y r the icentrifugal'casting clutch adapted for driving said rotary mold extend, parallel with the, axis of rotation, into recesses in the adjacent end of the mold, substantially as set forth.

11. Apparatus for the centrifugal casting of hollow bodies of metal, as claimed in claim 6 wherein the mold is provided at eachend with an inwardly-extending circumferential flange, the inner periphery of which is feathered.

12. Apparatus for the centrifugal casting of hollow bodies of metal comprising an uncooled rotary mold, means'for rotating said mold, means for depositing molten metal on the wall of said mold by projecting it in a plurality of jets and means for efiecting both relative longitudinal reciprocatory movement between the projecting means and the mold, and movement of the projecting means transversely of the mold. I

13. Apparatus, as claimed in claim 12, for the centrifugal casting of hollow bodies of metal, wherein the'mold is of open-ended cylindrical form and the projecting means comprises a tubular spout, adapted to project longitudinally into said mold, and provided with a plurality of laterally extending nozzles and means for feeding molten metal to, said tubular spout under a constanthead of pressure. j

14. Apparatus for the centrifugal casting of hollow bodies of metal, as claimed in claim 12, wherein the projecting-means comprises a tubular spout projecting longitudinally into said mold and provided with a plurality of laterally extending nozzles and means for feeding the molten metal to the tubular spoilt under a constant head of pressure, comprising a funnel-like receiver at one end of the tubular spout, which is closed at its other end, and a ladle pivoted about a horizontal axis above the level of said receiver, said ladle being formed at one end with an outlet for delivering molten metal to said receiver, and at its other end'with an overflow lip, substantially as described.

15. Apparatus for the centrifugal casting of hollow bodies of metal, as claimed in claim 12, wherein the projecting means, comprising a tubular spout provided with nozzles is mounted on a. carriage adapted to be moved longitudinally of the mold in order that said spout may be reciprocated in said mold, while the tubular spout is mounted on the carriage so as to be movable transversely thereof, sub

, stantially asand for the "purpose set forth JOHN CHAPMAN BELL.

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