US2739348A - Apparatus for making metal pellets - Google Patents

Description

March 27, 1956 Filed Oct. 5, 1953 V. A. RAYBURN APPARATUS FOR MAKING METAL PELLETS 3 Sheets-Sheet l FIG.

//v|//v TOR L A. RAYBURN A TTORNEV March 2?, 1955 v. A. RAYBURN 2,739,348

APPARATUS FOR MAKING METAL PELLETS Filed OGC. 5, 1953 3 Sheets-Shem 2 //vv/\/ TOR E E 1/1 A. RA VBURN 156 v. A. RAYBURN APPARATUS FOR MAKING METAL PELLETS Mach 2?;

3 Sheets-Sheet 3 Filed Oct. 5, 1953 M w W M l A wm M VA QEB States APPARATUS FOR MAKING METAL PELLETS Application October 5, 1953, Serial No. 384,101

12 Claims. (6i. 18-25) This invention relates to apparatus for making metal pellets, and particularly to apparatus for making substantially spherical metal pellets of relatively uniform size.

It has been the practice heretofore to make metal pellets by causing small globules of molten metal to fall from a substantial height and allowing the particles to fall into a pool of water. This procedure requires the construction of towers of great height, which are quite costly. Various types of wheels have been proposed, which throw metal particles outwardly by centrifugal force to form pellets, but none of these devices has been wholly satisfactory for producing metal pellets which are substantially spherical and of relatively uniform size. They also have had no means for varying or controlling the size of the pellets I produced thereby.

An object of the invention is to provide new and improved apparatus for making metal pellets.

Another object of the invention is to provide new and improved apparatus for making substantially spherical metal pellets of relatively uniform size.

An apparatus illustrating certain features of the invention may include a plate for receiving metal globules, means for causing a stream of molten metal globules to flow along the surface of a plate and means for cooling the plate to cause the globules to solidify into pellets while on the plate.

These and other objects and features of the invention will be apparent from the following detailed description of a specific embodiment thereof, when read in conjunction with the accompanying drawings, in which:

Fig. l is a vertical section of an apparatus for making metal pellets;

Fig. 2 is a fragmentary, top plan view of the apparatus, with some parts broken away;

Fig. 3 is a fragmentary, horizontal section taken along line 3-3 of Fig. 1;

Fig. 4 is a reduced, fragmentary, horizontalsection taken along line 4-4 of Fig. 1;

Fig. 5 is a fragmentary, horizontal section taken along line 5-5 of Fig. 1;

Fig. 6 is an enlarged plan view of a flutter valve shown in Figs. 1 and 2, and

Fig. 7 is an enlarged vertical section taken along line 7-7 of Fig. 6.

Referring now to the drawings, there is shown a standpipe 10 having a refractory lining 11 provided with a funnel-like cavity 12 at the top thereof into which molten metal 13, such as molten copper, is introduced through a pouring spout 14, or the like. Communicating with the cavity 12 in the liner 1! is a central bore 16, and at the bottom of the liner there is formed a concave recess 17. The bore 16 is relatively small in diameter and is elongated to enclose a column of molten metal. Due to the shape of the wide-mouthed, funnel-like cavity 12, a large amount of molten metal may be poured into the cavity to keep the bore 16 filled, and an appreciable variation in the volume of molten metal may occur without altering materially the pressure head developed at the bottom of the bore 16.

plate 22. The cam plates 20 and '22 are so designed that,

When the standpipe 10 is rotated about its axis in one direction, it is raised, and when it is rotated in the opposite direction, it is lowered. When the standpipe is positioned as desired, it may be secured in that position by means of a pin 24 passing through an ear 25 formed at the left hand side of the standpipe, as seen in Figs. 1. and 2. The pin 24 may engage any one of a plurality of sockets 26-26 formed in an arcuate segment 27.

Positioned beneath the standpipe 10 is a dome-shaped spill head 30, the upper surface of which matches the concave recess 17. The molten metal fed to the concave recess 17 through the bore 16 flows through a restricted passage 31 formed by the wall of the recess and by the domed top of the spill head 34). The contour of the passage 31 causes the molten metal to fall'otr of the domeshaped top of the spill head 30 in the form of a thinwalled, annular curtain 32, the thickness of which will depend upon the size of the passage through which the metal flows. The size of the passage 31 is adjusted by raising or lowering the standpipe ill by means of the annular earns 20 and 22. The spill head 30 is secured to a raised central portion 33 of a rotatable, circular cooling table 34, so that the spill head rotates with the table while the standpipe it), which, after having been adjusted vertically to provide the desired passageway for the molten metal, remains stationary. If any dross is present in the molten metal, it will be pulverized by the grinding action of these relatively moving elements so that the slag will not clog the passage 31.

Located close to the point Where the molten metal curtain 31 falls off of the edge of the spill head 30 and positioned therearound, are a plurality of nozzles 35-35 secured to an annular header 36. Steam, or other nonoxidizing vapor or gas, is supplied to the header 36 by means of a pipe 37 leading from allutter valve 39 having an inlet 40 connected thereto. For the purpose of this description, it will be assumed that steam is fed to the flutter valve 39 through the inlet 49. The flutter valve repeatedly interrupts the flow of steam into the header 36, and thus through the nozzles 35-35, so that pulsating jets of steam emerge from the nozzles and impinge upon the annular curtain 31 of molten metal falling downwardly The pulsating steam jets break around the spill head 30. up the falling curtain 31 of molten metal into globules or droplets 43-43, which then fall upon the table34.

In order to increase the effectiveness of these jets in breaking up the stream of metal into globules 43-43, and

The globules 43-43 of molten metal produced when I the jets of steam impinge upon the curtain 31 of metal fall upon the raised central portion 33 of the table 34, and-flow downwardly and outwardly so that they pass over the surface of the table in the form of constantly expanding spirals (Fig. 4) The upper surface of the table 34 hasa profile of a high order curve, which takes into account the frictional, gravitational and centrifugal forces acting on. the globules 43-43, so that the globules roll on the table surface in the manner of a curving ball. The

size of the molten globules governtheir rate of fall, while.v

Patented Mar. 2?, 1956.

. 3 the speed of rotation of the table 34 governs the rate at which they roll outwardly towards the'edge of the table.

If a globule of molten metal were allowed to fall squarely upon a flat surface, it would break up into smaller particles which would splatter in all directions. The table 34 is so designed that the globules 43-43 impinging thereon strike the table with glancing blows in order to reduce the force of the impact sufiiciently to prevent the shattering of the globules. This is accomplished by having the surface of the table 34 curved sharply downwardly from an almost vertical direction at the raised center portion 33 just beneath the spill head to a nearly horizontal direction at an intermediate portion 45.

This configuration of the table 34 utilizes the energy of the falling globules 43-43 to produce rolling motion down an inclined plane, and causes the centrifugal force generated by the rotation of the table 34 to act upon the rolling globules 4343 quickly so as to move them outwardly from the central portion of the table as soon i as possible. This is desirable for several reasons, among which are to remove the globules as quickly as possible away from the regions where the hottest and most fluid globules strike the table, and to keep these globules. from crowding together and coalescing into larger globules before they have cooled sufliciently to develop solidified spherical shells.

As the solidifying globules roll outwardly on the table, they follow gradually expanding, spiral paths, and their pitch velocity increases as the efiective radii of these paths increase. In order to prevent the solidifying globules from being thrown otf of the table before they are completely cooled into solid pellets, the surface of the table curves gently upwardly in the region 46 of its outer edge. This upward curvature of the table forces the outwardly moving globules to roll up an inclined plane and to lose some of their pitch velocity, while at the same time they retain most of their tangential velocity. In this region the globules have chilled into solidified pellets which are still warm, but which have no further tendency to stick together or coalesce. Consequently, the pellets may be crowded closely together near the edge of the table 34 so as to utilize the cooling area of the table with maximum efiiciency. The upwardly curving portion 46 of the surface also reduces the force with which the cooled pellets are thrown ad of the table 34.

The approximate expanding spiral path followed by one group of globules 43-43 as they rollover thev surface of the table 34 is shown inFig; 4. It will be noted that the globules are widely spaced at first so that they do not coalesce, but that they are crowded together near the edge of the table 34 so that they may have the maximum efiect of the chilling action of the table. It will, of course, be evident that many groups of the globules 43--43 will be following similar, more'or less independent, expanding spiral paths across the upper surface of the table 34. However, for sake of clarity, onlyone such path is shown in Fig. 4.

The natural optimum size of a truly spherical globule or droplet of molten metal is a function of its mass and of the pressure exerted thereon due-to surface tension. This pressure, which acts to hold the droplet in spherical form, decreases as the diameter of the droplet increases and, therefore, the greater the diameter of the droplet the less tendency there is for it to retain a spherical form.

However, it is possible to increase materially the natural optimum size of a droplet if it is kept in multiple rolling motion and simultaneously cooled until it solidifies.

Thisresult is achieved by providing an uppercooling falling thereon to roll across the surface of, the table in.

a compound motion' along constantly expanding spiral 4 paths. It also prevents the globules from striking th table squarely so that the globules are not broken into smaller particles. The ultimate result of these factors is the production of solid pellets which are substantially truly spherical and which are of optimum size.

The table 34 is made up of two parts, one of which is an upper half 49 having the upper surface of the configuration described previously, and upon which'thexglobules 43-43 of molten metal fall. The outer edge of the upper half 49 of the table 34 has a depending flange 50 to which is bolted a lower half 52 so as to form a'watertight joint therebetween. The central part of the lower half 52 is in the form of a hollow shaft 53 having spacedly mounted thereon a pair of radial thrust ball bearings 5555, which in turn are supported in a hollow pedestal 57. Fixedly mounted to the hollow shaft 53 is a worm gear 58, which is turned by means of a worm mounted on a shaft 61. The shaft 61 is connected to a changespeed gear box 64 actuated by a motor 65. By this means-- the table 34, consisting of the halves 49 and 52 bolted securely together, is caused to rotate at the desired speed in the direction indicated by the arrow in Figs 4.

The halves 49 and 52 of the table 34 are so designedas to leave a cavity 66 therebetween in which is located a stationary, flared vane 68. The vane 68 has a configuration conforming to that of the cavity 66, so as to provide channels 69 and 70 between the vane and the upper and lower halves 49 and 52, respectively, of the table 34. The central part of the vane 68 is in the form of'a hollow supporting stem 71, which extends through. the hollow shaft 53 and is supported by a fixed base 72. The supporting stem 71 has an outer diameter smaller than the inner diameter of the hollow shaft 53, so'that an annular channel 74 is formed therehetween.

Cooling water is introduced from asuitable external source (not shown) into the central bore of the pedestal 71, and flows upwardly into the channel 69. Thiswater then passes outwardly through the channel 69 between the vane 68 and the upper half 49 of the table 34, thenflows over the edge of the vane and passes inwardly, through the channel 70 between the vane. and the lower half 52 of the table. Finally the water flows downwardly through the annular channel 74 into a sump 75, from which it may be removed by a suitable circulating. pump (notshown).

Because of this arrangement, the rotation of the table efiects a constantly increasing film velocity betweenthecooling water in the channel 69 and the inner wall-of the upper half 49 of the table 34 as the waterprogresses towards the outer edge of the table, thereby increasing the'rate of heat transfer and the cooling efiiciency. The rotation of, the table 34 urges the cooling water outwardly'and' causes the water to fill the entire channel 69,- which assures full contact between the water and the inner surface of the upper half 49.

The coldest water which is introduced throughfthe bore in the pedestal 71 contacts the central portion of theupper half 49 of the table 34 at the point where the hottest metal globules strike the table. As a result, the most rapid transfer of heat is efiected at that part of the table 34 where it is necessary to chill the globules sufficiently. to form a solidified skin thereon as quickly as possible. The vane 68 is entirely surrounded by water and, consequently, can never become overheated. Likewise; the hollow'shaft 53, forming a part of' the lower half 52 of thetable 34; is water cooled so thatit cannot become overheated and, in consequence, the bearings associated therewith are protected against excessive heating.

The channel 69'is relatively wide in the central region thereof to reduce'the velocity of how of the water sons to 69 and 70 are narrow at their outer peripheries to increase the velocity of flow of the water in' that region The water is warmed considerably during its passage from the central portion of the channel 69 to the outermost limit of that passage. Therefore, it has less and less cooling effect as it approaches the edge of the table 34. By increasing the rate of flow of the Water in the outer portion of the channel 69, the rate of heat transfer between the relatively cool pellets on the outer portion of the table 34 is increased accordingly. By this arrangement the cooling water acts most effectively to chill the globules falling upon thetable and to constantly cool the globules, and the pellets resulting from the solidification thereof, as they progress outwardly to the periphery of the table 34.

The hood 81 which surrounds the table 34 has an inwardly extending, annular rim 81 (Fig. 5) having notches 83-53 formed therein, leaving tongues 84-84 projecting between the notches. The tongues 84-84 on the rim 81 rest upon tongues 85-85 formed on an annular, horizontal deflector plate 87. Positioned beneath the deflector plate 87 is an annular spacer member 88 made of sheet metal bent into loops 89-89, which serve to position drums 9-11-91 for receiving the metal pellets produced in the apparatus. The loops 89-89 are positioned directly below the tongues 85-85 on the deflector plate 37. The deflector plate 87 is secured to an annular, vertical baflle 92 having an outwardly extending flange 93. The pellets ejected from the periphery of the plate 34 strike the inner wall of the hood ill) and fall through openings between the tongues 84-84 and 85-85 into the drums 913-91).

Since the molten metal globules formed when jets of steam strike the curtain of molten metal above the table 34 would oxidize rapidly in an oxidizing atmosphere, it is desirable to maintain a nonoxidizing atmosphere beneath the hood 81 The entire space under the hood 80 and surrounding the table 34 is filled with a suitable gas by means of nozzles 95-95 (Figs. 1 and 5) projecting from an annular manifold 96 positioned just beneath the flange 93 on the baflie 92. Any desired nonoxidizing gas may be introduced into the manifold 96 from a suitable supply pipe (not shown). It would be feasible to introduce into the manifold 96 the exhaust gases from the furnace used to melt the molten metal poured into the standpipe 111, or from other metallurgical processes which might be carried on in the vicinity of the apparatus. If desired, steam could be substituted for such exhaust gases.

The cam 22, upon which rests the cam 21) supporting the standpipe 11b, is fixedly positioned on the top of an exhaust head 19!). The upper portion of the hood 80 is secured to the exhaust head 109 so that the exhaust head communicates with the interior of the hood. The exhaust head 188 communicates through a transition section 101- 101 with an exhaust fan 1113 actuated by a motor 104. The interior of the exhaust head 101i is provided with a plurality of splitters (Figs. 1 and 2), which divide the exhaust head into sections of such dimensions that the suction head created by the fan 103 is equalized over all portions of the open bottom of the exhaust head. Hence, all fumes and gases are evacuated evenly from the space above the table 34. The fumes and gases exhausted from beneath the hood 81) by the fan 103 are expelled into a stack 167 leading upwardly into the air.

The steam emitted by the nozzles 35-35 and the gases emitted by the nozzles 95-95, together with any fumes and vapors arising from the molten metal globules, create a positive pressure within the hood 80. Consequently, insufiicient air enters the apparatus to oxidize the molten metal globules. The air surrounding the apparatus is kept free from gases and fumes by the action of the fan 1113, which draws these fumes out of the apparatus and into the stack 107. The fan 103 may be provided with suitable dampers of conventional design to regulate the volume of gases exhausted from beneath the hood St), so as to avoid the inspiration of an excess amount of air into the apparatus near the bottom of the hood. The rotation of the table 34 causes a fan action, which insures an-even diffusion of the inert gases surrounding the molten metal globules on the table.

The flutter valve 39 includes a casting (Figs. 6 and 7) having an inlet port 111 to which the inlet pipe 40 is connected to introduce steam into the interior thereof. The inlet port 111 communicates with a Y-shaped channel 114 in the interior of the casting 110, which terminates in two circular openings 115-115 formed at the bottom of a circular recess 117 formed in the casting 110.

A companion casting 120, which is identical with the casting 110, is connected to the casting 110 by means of suitable draw bolts so as to form a steam-tight seal between the castings. The casting 120 has an outlet port 121 formed therein to which the pipe 37 is connected. The casting 120 is provided with a Y-shaped internal channel 124, which is similar to the channel 114 in the casting 110 and which terminates in circular openings 127-127 directly opposite to the openings 115-115. The casting 1120 has a circular recess.128 formed therein into which the openings 127-127 lead, and which coincides with the recess 117 in the casting 120.

Before the castings 110 and 120 are secured together, a rotary valve disc 130 is positioned within the recesses 117 and 128. A shaft 131, secured to the disc 130, projects outwardly through the castings 110 and 120, and glands 132-132 prevent leakage of steam around the shaft. A stepped pulley 13 (Fig. 2) is secured to the shaft 131, and a motor 134 has a stepped pulley 135 secured thereto. A belt 136 connects the pulleys 133 and 135, and by this means the disc 130 is rotated. The disc 130 is provided with two circular ports 137-137 spaced 180 apart in alignment with the openings 115-115 in the casting 110 and the aligned openings 127-127 in the casting 120.

It is obvious *that, when the disc 130 is rotated by means of the motor 134, the ports 137-137 therein will successively be aligned with the openings 115-115 and 127-127 in the bottoms of the recesses 117 and 128, and successively not aligned with those openings. Consequently, the steam entering the port 111 is intermittently connected through the channels 114 and 124 with the exit port 121, and intermittently shut off. As a result, a pulsating flow of steam emerges from the flutter valve 39, through the pipe 37, into the header 36, and out of the nozzles 35-35, causing pulsating jets of steam to be emitted by the nozzles. The sizes of the piping and of the channels in the flutter valve will be such as to provide sharp pulsations of the steam through the nozzles 35-35 without any cushioning effect.

In order to change the rate of these pulsations, another disc, similar to the disc 130 but having more ports therein like the ports 137-137, or having arcuate-shaped ports, may be substituted for the disc 130. Likewise, the speed of the motor 134 may be changed by means of a variable motor control of known design. If desired, the

drive between the motor 134 and the shaft 131 may be changed in such manner as to vary the speed of rotation of the disc 130. This may be accomplished by shifting the drive belt 136 from one step of the stepped pulley 135 to another step thereon, and simultaneously shifting the belt to another step of the pulley 133 mounted on the shaft 131.

A steel frame 140 supports the various elements of the apparatus positioned above the table 34, and this frame is provided with suitable crossbars to which the various members are secured. A steel decking 141 is positioned upon the top of the framework to provide a platform upon which an operator may stand while directing molten metal into the spout 14. A door 143 is provided in the baflie 92 to permit access to the apparatus in the area beneath the table 34.

The entire standpipe 10 may be lifted from the apparatus by means of cars 145-145 secured to the upper portion thereof. When the liner 11 becomes eroded by the action of molten metal pouring thereon, it is necessary to remove the standpipe 10 and replace the liner. If desired, a spare standpipe may be kept available to replace one that is removed for replacement of the liner.

It is believed that the operation of this apparatus will be clear from the foregoing description. It will be obvious that various changes and modifications may be made therein without departing from the spirit and scope of the invention. While the apparatus has been described as being suitable for the manufacture of copper shot, pellets or shot of other metals, such as iron, lead, zinc, and the like, may be made by means of apparatus of this same general design.

What is claimed is:

1. Apparatus for making pellets, which comprises a horizontally disposed, circular plate for receiving metal globules, means for causing a stream of molten metal globules to fall upon the upper surface of the plate near the center thereof, means for rotating the plate to cause the globules to roll over the plate to and off the periphery thereof, means for causing a cooling fluid to impinge upon the lower surface of the plate beneath the centralportion thereof and to flow outwardly along the plate to the periphery thereof to cool the plate sufficiently to cause the globules to solidify into pellets while on the plate, and means for increasing the velocity of the flow of the cooling fluid relative to the plate as the fluid approaches the periphery of the plate to increase the rate of heat transfer between the fluid and said pellets.

2. Apparatus for making pellets, which comprises a circular, horizontally disposed plate having a horizontal chamber therein extending from the central portion to the outer portion thereof, a sationary, horizontal vane positioned within the chamber so as to divide the chamher into upper and lower channels which communicate only at their outer peripheries, said vane being of such configuration that the upper channel is thicker in crosssection near its center than at its outer portion, means for causing an annular stream of molten metal globules to fall upon the central portion of the plate, means for rotating the plate to cause the globules to roll over the plate to and otf the periphery thereof, means for introducing cold water under pressure into the upper channel at the center thereof, and means for permitting water to flow from the lower channel at the center thereof, whereby the cold water enters the center of the upper channel, flows outwardly therethrough to the periphery thereof and then flows inwardly through the lower channel and out of the center thereof to chill the plate sufiiciently to convert the metal globules rolling thereover into solid pellets and to cool said pellets.

3. Apparatus for making metal pellets, which comprises a horizontally disposed, circular plate for receiving metal globules, means for causing a stream of molten metal globules to fall upon the upper surface of the plate, means for rotating the plate to cause the globules to be carried by centrifugal force in spiral paths to and off of the periphery of the plate, and means for cooling the plate to cause the globules to solidify into pellets while on the plate, said upper surface of the plate being curved so as to cause the speed of the globules first tobe accelerated and finally to be decelerated as they near the periphery of the plate whereby the cooling of the pellets is increased and the speed of the pellets is decreased as they approach the periphery of the plate.

4. Apparatus for making metal pellets, which comprises a horizontally disposed, circular plate for receiving metal globules, means for directing a stream of molten metal toward the plate, means for directing a pulsating jet of gas upon the stream of metal to break the metal in the stream into small globules which fall upon the plate, means for rotating the plate to cause the globules to be carried to the periphery of the plate, and means for cooling the plate to cause the globules to solidify into pellets while on the plate.

5. Apparatus for making metal pellets, which comprises a circular, horizontally disposed, metal plate for receiving metal globules, a standpipe positioned above the plate for holding a supply of molten metal, means for causing molten metal to flow from the standpipe in a stream towards the plate, means for varying the rate of flow of the metal in said stream, means for directing a pulsating jet of gas upon the stream of metal to break the metal in the stream into small globules which fall upon the plate, means for rotating the plate to cause the globules to be carried to the periphery of the plate, and means for cooling the plate to cause the globules to solidify into pellets while on the plate.

6. Apparatus for making metal pellets, which comprises a circular, horizontally disposed, rotatable, metal plate for receiving metal globules, means for causing molten metal to flow in an annular stream towards the plate, a plurality of nozzles arranged in a circle around the annular stream of metal and directed downwardly, inwardly and obliquely counter to the direction of rotation of the plate, means for causing pulsating jets of steam to flow through the nozzles so as to impinge upon the annular stream of metal and break the stream into globules which fall upon the plate, means for rotating the'plate to cause the globules to he carried to the periphery of the plate, and means for cooling the plate to cause the globules to solidify into pellets while on the plate.

7. Apparatus for making metal pellets, which comprises a circular, horizontally disposed, rotatable, metal plate for receiving metal globules, means for causing molten metal to fiow in an annular stream towards the plate, a plurality of nozzles positioned about and directed generally toward the annular stream of metal, a pipe connecting the nozzles to a source of steam under pressure, a flutter valve in the pipe for intermittently interrupting the flow of steam through the pipe and thereby causing pulsating jets of steam to be emitted from the nozzles upon the annular stream of metal, whereby the stream is broken into small globules which fall upon the plate, means for changing the rate of operation of the flutter valve to vary the frequency of the pulsating jets of steam, means for rotating the plate to cause the globules to be carried to the periphery of the plate, and means for cooling the plate to cause the globules to solidify into pellets while on the plate.

8. Apparatus for making metal pellets, which comprises a standpipe for holding a supply of molten metal, means for causing molten metal to flow downwardly from the standpipe in a thin, annular stream, means for varying the rate of flow of metal in said annular stream, a circular, horizontally disposed, metal plate having its axis coincident with the axis of the annular stream of metal, means for directing a plurality of pulsating jets of gas inwardly upon the annular stream of metal to break the molten metal into small globules which fall upon the upper surface of the plate, means for rotating the plate to cause the globules to be carried by centrifugal force in spiral paths to and off of the periphery of the plate, and means for cooling the plate to cause the globules to solidify into pellets while on the plate, said upper surface of the plate being curved so as to cause the speed. of the globules first to be accelerated and finally to be de celerated as they near the periphery of the plate whereby the end-cooling of the pellets is increased as they approach the periphery of the plate and the speed of the pellets is decreased as they are thrown from the plate.

9. Apparatus for making metal pellets, which comprises a standpipe for holding a supply of molten metal, means for causing molten metal to flow downwardly from the standpipe in a thin, annular stream, means for varying the rate of How of metal in said annular stream, a circular, horizontally disposed, metal plate having its axis coincident with the axis of the annular stream of metal, means for directing a plurality of pulsating jets of gas upon the annular stream of metal to break the stream into small molten globules which fall upon the upper surface of the plate, means for varying the frequency of the pulsations of the jets of gas, means for rotating the plate to cause the globules to be carried by centrifugal force in spiral paths to and off of the periphery of the plate, and means for cooling the plate to cause the globules to solidify into pellets while on the plate, said upper surface of the plate being curved so as to cause the speed of the globules first to be accelerated and finally to be decelerated as they near the periphery of the plate whereby the end-cooling of the pellets is increased as they approach the periphery of the plate and the speed of the pellets is decreased as they are thrown from the plate.

10. Apparatus for making metal pellets, which comprises a circular, horizontally disposed, metal plate for receiving metal globules, means for causing a multiplicity of molten metal globules to fall upon the upper surface of the plate near the central portion thereof, means for rotating the plate to cause the globules to be carried by centrifugal force in spiral paths to and off of the periphery of the plate, and means for cooling the upper surface of the plate to cause the globules to solidify into pellets while on the plate, said upper surface of the plate being steeply sloped at the central portion thereof so that the globules strike the plate with glancing contact, then being curved sharply to a substantially horizontal plane to cause the centrifugal force exerted by the rotating plate to act quickly on the globules and finally being curved upwardly near the periphery of the plate to decrease the speed and to increase the end-cooling of the pellets as they approach the periphery of the plate.

11. Apparatus for making metal pellets, which comprises a circular, horizontally disposed, metal plate for receiving metal globules, means for causing molten metal to fall in a thin, annular stream towards the central portion of the plate, means for directing a plurality of pulsating jets of steam upon the annular stream of metal to break the stream into small metal globules which fall upon the upper surface of the plate, means for rotating the plate to cause the globules to be carried by centrifugal force in spiral paths to and off of the periphery of the plate, means for cooling the upper surface of the plate to cause the globules to solidify into pellets while on the plate, and means for maintaining a nonoxidizing atmosphere within the apparatus to prevent oxidation of the said pellets, said upper surface of the plate being steeply sloped outwardly at the central portion thereof so that the globules strike the plate with glancing contact, then being curved sharply to a substantially horizontal plane to cause the centrifugal force exerted by the rotating plate to act quickly on the globules and finally being curved upwardly near the periphery of the plate to decrease the speed and to increase the cooling of the pellets as they approach the periphery of the plate.

12. Apparatus for making copper shot, which comprises a housing, a standpipe for holding a supply of molten copper and having a concave recess at the lower end thereof positioned within the housing, a circular, horizontally disposed, metal plate positioned within the housing beneath the standpipe and having a convex member at the center thereof projecting into the concave recess in the standpipe whereby molten copper placed in the standpipe will flow outwardly over the convex member and fall therefrom toward the plate in the form of a thin, annular sheet, means for varying the spacing between the concave recess and the convex member so as to adjust the rate of flow of molten copper in said annular stream, means for directing a plurality of pulsating jets of steam upon the annular stream of molten copper to break the stream into small, metal globules which fall upon the upper surface of the plate, means for varying the frequency of the pulsations of the jets of steam, means for rotating the plate to cause the globules to be carried by centrifugal force in spiral paths to and off of the periphery of the plate, means for cooling the upper surface of the plate to cause the globules to solidify into pellets while on the plate, means for introducing a nOnOXidiZing gas into the interior of the housing to prevent oxidation of the said pellets, and means for exhausting gas from the housing, said upper surface of the plate being steeply sloped at the central portion thereof so that the globules strike the plate with glancing contact, then being curved sharply to a substantially horizontal plane to cause the centrifugal force exerted by the rotating plate to act quickly on the globules so as to throw them rapidly outwardly and finally being curved upwardly near the periphery of the plate to decrease the speed and to increase the cooling of the resulting pellets as they approach the periphery of the plate.

References Cited in the file of this patent UNITED STATES PATENTS 1,647,194 Poindexter et al. Nov. 1, 1927 1,915,201 Ragg June 20, 1933 1,939,391 Curran Dec. 12, 1933 2,240,182 Guldner Apr. 29, 1941 2,269,528 Gallup Jan. 13, 1942 2,304,130 Truthe Dec. 8, 1942 2,439,772 Gow Apr. 13, 1948 2,630,783 Reeve Mar. 10, 1953 OTHER REFERENCES Serial No. 268,381, Kaufmann (A. P. 0.), published July 13, 1943 (abandoned).

Claims (1)

1. 4. APPARATUS FOR MAKING METAL PELLETS, WHICH COMPRISES A HORIZONTALLY DISPOSED, CIRCULAR PLATE FOR RECEIVING METAL GLOBULES, MEANS FOR DIRECTING A STREAM OF MOLTEN METAL TOWARD THE PLATE, MEANS FOR DIRECTING A PULSATING JET OF GAS UPON THE STREAM OF METAL TO BREAK THE METAL IN THE STREAM INTO SMALL GLOBULES WHICH FALL UPON THE PLATE, MEANS FOR ROTATING THE PLATE TO CAUSE THE GLOBULES TO BE CARRIED TO THE PERIPHERY OF THE PLATE, AND MEANS FOR COOLING THE PLATE TO CAUSE THE GLOBULES TO SOLIDIFY INTO PELLETS WHILE ON THE PLATE.

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