US2910744A

US2910744A - Apparatus for producing metal filaments

Info

Publication number: US2910744A
Application number: US555085A
Authority: US
Inventors: Robert B Pond
Original assignee: MARVALAND Inc
Current assignee: MARVALAND Inc
Priority date: 1955-12-23
Filing date: 1955-12-23
Publication date: 1959-11-03
Anticipated expiration: 1976-11-03

Description

Nov. 3, 1959 R. B. POND APPARATUS FOR PRODUCING METAL FILAMENTS Filed Dec. 23, 1955 2 Sheets-Sheet 1 APPARATUS FOR PRODUCING METAL. FILAMENTS Filed D60. 23, 1955 R. B. POND Nov. 3, 1959 2 Sheets-Sheet 2 United States Patent? 2,910,744 Patented Nov. 3, 1959 ice APPARATUS FOR PRODUCING METAL 5 FILAMENTS Application Decemher23, 1955, Serial No. 555,085

6 Claims. 01. 22-s7.2

This application relates to improvements in the produc- 5 tion of a cast filament, and is a continuation-in-part of my copending application Metallic Element and Method and'Apparatus, Serial No. 387,187, filed October 20, 1953, now Patent No. 2,825,108, issued March 4,. 1958.

Generally, the invention described in the above-noted application deals with the transformation of molten metal intoa solid product in the nature of a filament by causing a continuous stream of molten metal to impinge on theopen concave surface of a rapidly rotating chill block. The chill block removes the superheat and the latent heat of fusion from the stream of molten metal, thereby causing it to solidify and be centrifugally discharged from the'chill clock. While the inventive concept set forth in said copending application has utility with various metals, only a single filament is normallyfoimed at one time. Thus, the apparatus has limited productive capacity and is not adapted for simultaneously spinning a plurality of continuous filaments of the same or different metals of non-metallic materials which are either independently collected'or alowed to intermix to provide a desired blend of filaments; It is therefore a primary object of the present invention to provide a generally improved and more satisfactory method and apparatus for simultaneously producing a plurality of cast filaments.

Another object is the provision of an apparatus for producing a plurality of filaments by impinging a number of independentstreams of molten metal on the open surface of a single chill block.

Still another object is to provide an apparatus including a plurality of chill blocks rotatably interengaged with each other for simultaneous movement relative to individual streams of molten metal for mass-producing filaments of the same or different materials.

A further object is the provision of a simple and reliable drive means for simultaneously rotating a plurality of chill blocks at high speeds.

A still further object is to provide an improved method and apparatus adapted for mass production of continuous filaments which can be individually collected or intermixed to provide a blend of filaments of various materials and/ or of different diameters.

These and other objects and advantages of the invention will be apparent from the following description and accompanying drawing in which:

Figure l is a perspective view illustrating one embodiment of the present invention wherein a plurality of independent streams of molten metal are ejected onto a single chill block;

Figure 2 isa viewsimilar to Figure 1 showing independent ejection nozzles positioned to cause the individual streams to impinge the single'chill block at points spaced along a circle concentric with the chill block periphery;

Figure 3 is a diagrammatic view illustrating an apparatus for simultaneously producing a plurality of filaments by employing a bank of integrally connected chill blocks, each supplied by a stream of molten'metal ejection through an independent nozzle;

Figure 4 is a perspective view showing atplurality of chill blocks having a common drive and individually supplied witha stream of molten metal through separate nozzle having a common supply source; and

Figure 5 is a plain View, partly in section, showing a modified drive for simultaneously rotating a plurality of chill blocks.

in general, the invention relates to the simultaneous production of a plurality of filaments by impinging independent streams of molten metal on individual chill blocks or atdiiferent radially or annularly spaced points along the same chill block where the streams are rapidly cooled and centrifugally discharged as solidified filaments. The filaments so formed can be collected separately or as an intermixed mass to provide a blend of filaments of the same or different metallic materials or a combination of metallic and non-metallic materials having the same or different cross-sectional dimensions.

As more fully explained in my copending. application, the method of the invention there described can be controlled to such an extent as to provide an extremely small element which. has. a length to Width ratio approaching unity so that the filament becomes a particle of flake powder. Therefore, in conformance with said pending application, the term filament as used in the following specification and claims is intended to be all inclusive of elements of powder .form as well as those having a substantial length.

The chill blocks employed in each of the various embodiments of the present invention, as hereinafter described, are preferably formed of material having high thermal conductivity and strength and are of the same general open concave construction as set forth in my above-noted copending application. Accordingly, it will be understood that any reference made to a chill block in the following description is intended to read upon or cover a chill block having the same functional and structural characteristics as specifically described and claimed in said copending application.

As illustrated in Figure 1 of the drawing, a multiple of filaments may be simultaneously produced by ejecting a plurality of continuous and independent streams of molten metal onto the open concave surface 11 of chill block 13. The continuous flow of molten metal is preferably accomplished by means of ejection tubes 15, each provided with a nozzle 17 at its end 19 nearest the chill block 13. The nozzles 17 are each provided with a restricted orifice, and for ease of cleaning and replacement are removably mounted on their respective ejection tubes. As shown on the drawing, the ejection tubes 15 are inclined downwardly toward the chill block with their ends 19 togtther forming an are approximately parallel to the outer periphery of the chill block. In this manner, the distance of travel of each of the molten metal streams from its respective nozzle to the open surface of the chill block is substantially the same, and thus all the streams impinge against the open surface 11 along a line extending radially of the chill block. The number of ejection tubes employed, their particular configuration and their positioning may, of course, vary with the size of chill block being utilized and the production requirements to be satisfied.

When forming filaments of different metals or when it is desired to produce a mixture of metallic and non-metallic filaments, the individual ejection tubes or those ejection tubes which are to receive different materials are of course supplied through a separate supply system. However, when ejecting the same molten material, the ejection tubes 15 are supplied through a distribution system, as shown in Figure 1, including a separate duct 21 connecting each of the ejection tubes 15 to a header 23, which in turn is supplied with molten metal under pressure from a source not shown, as indicated by the arrow 24. Any conventional means, as for example thermal insulation or auxiliary heating elements may be placed about or'adjacent to the distribution system and ejection tubes to maintain the metal in a molten condition and at the desired degree of superheat.

In the production of filaments, the chill block 13 is first placed in operation by rotating the same about its vertical axis by any suitable means, not shown. The rotational speed required will of course vary with the material being impinged thereon, with speeds ranging from ten to thirty thousand revolutions per minute (r.p-.m.) being generally satisfactory. Once the chill block has attained the desired speed, molten material is passed through the header and ducts into the tubes 15 from which it is ejected by means of the nozzles 17. The ejected streams follow paths which are approximately parallel and equal in length until they impinge against the open chill surface 11. As set forth in greater detail in my copending application, the concavity of the chill block en ables the molten metal to strike the chill surface with a greater normal force causing the surface of the metal to rupture at the point of impact. This breakdown in the surface tension of the molten stream produces the intimate contact between the stream and chill surface necessary to enable the rapidly rotating chill block to remove both superheat and the latent heat of fusion from the plurality of molten streams and effect their solidification.

The filaments, once formed, travel along with the chill block through a small arcuate path and are then discharged therefrom. Although the centrifugal force developed by the rotating chill block acts to cast the filaments off the chill surface, various factors, such as the air drag and the friction between the filaments and the chill surface, cause the filaments to travel paths which lie in planes intermediate similar planes extending tangentially and radially of the chill block.

While the above method has been described with parables, such as the temperature of the molten metal, veloc ity of ejection from the ejection tubes, size of orifice, and the surface speed of the rotating chill block 13 at the point of impingement as more fully described in said copending application. Collection of the filaments can be made by any suitable means, and where it is desired to form a mass of intermixed metallic or metallic and nonmetallic filaments it is only necessary to dispose a collection bin in the area in which the filaments are thrown off the disk.

With the structure shown in Figure 2, a plurality of filaments can be also simultaneously produced. However, in this embodiment, the ejection tubes 25 are spaced annularly about the chill block 27 and disposed at an angle to each other so that the streams of molten material ejected through the nozzles 29 all impinge the chill block 27 at points approximately equidistant from the center of the block 27. In addition, the positioning arrangement shown in Figure 2, enables each of the plurality of filaments to be discharged at a different location, thus enabling easier collection where it'is desired to maintain the individual filaments separate from the others.

The chill block 27 is of the same construction as that set forth above and in my copending application, and the operation of the arrangement shown in Figure 2 is the same as that illustrated in Figure l and described above. The ejection tubes 25 may be each supplied with the same material in a somewhat similar'manneras that shown in Figure l or may be individually fed through separate means. An advantage of this construction over that shown in Figure 1 is that filaments of the same crosssectional shape and length can be produced, providing of course that the material, its temperature, its ejection velocity, and the orifice sizes are the same. While not shown on the drawing, it is preferred to mount each of the ejection tubes 25 to either a common or independent fixed supporting structure, as for example by means of a universal joint construction, to permit the point of impingement of each of the multiple streams of molten metal to be independently shifted radially of the block 27 and thus enable a variation in the physical characteristics of the particular filaments produced.

The invention embodiment illustrated in Figure 3 is similar to that shown in Figure 2 in that a plurality of filaments of the same cross-section and of either short or long lengths can be simultaneously produced. In this construction however, separate chill blocks 31, each of which is similar to the others and to those heretofore described, are employed with each of the ejection tubes 33. The chill blocks 31 are fixed, in vertically spaced relationship, to the central shaft 35 supported at one end by the bearing 37, fixed to underside of the horizontal arm 39 of the main frame 41, while its opposite end passes through a bearing 43, carried by the base plate 45. Any convenient means may be utilized for rotating the shaft 35. The operation of this structure is the same as that shown in Figures 1 and 2, and as noted in regard to the apparatus disclosed in Figure 2, the individual ejection tubes 33 are preferably mounted to the frame 41 or other fixed structure by a universal joint construction to permit the point of impingement of the individual streams of molten metal to be independently varied radially of its particular chill block.

The embodiment of the invention shown in Figure 4 is particularly suited for volume production and includes a fixed base or frame structure 47 having a table 49 provided with a concentric ring of circular interconnecting openings 51 on its upper face. A chill block 53, which is of the same general construction as those described above, is disposed within each of the open ings 51, with its peripheral edge 55 being in frictional engagement with the corresponding edges on the blocks adjacent thereto. Preferably, the peripheral edges 55 are coated with a suitable material, such as rubber to insure good frictional contact between the parts. The shafts 57 of each of the chill blocks 53 pass through suitable bearings 59 fixed to the table 49 and are engaged by means capable of rotating the blocks at the desired speeds.

Rotary movement is imparted to the chill blocks 53 by means of a central drive shaft 61 having its upper end mounted for rotary motion within the bushing 62 carried by the table 49, while its lower end is turned by any suitable means, not shown. Fixed to the drive shaft 61 is an annular friction collar 63 against which engages the friction disk 65 carried at one end of the intermediate shaft 67. A bushing 69, fixed within an elongated aperture in the projection 70 depending from the undersurface of the table 49, provides a bearing for the shaft 67 as it is turned by reason of the engagement between the disk 65 and collar 63. The end of the shaft 67 opposite the disk 65 carries a friction cone 71 which contacts and rotates a similar cone 73 fixed to the lowermost end of one of the shafts 57. As with the peripheral edges of the chill blocks 53, the friction collar 63, disk 65, and cones 71 and 73 are preferably provided with a suitable coating, such as of rubber, to insure that good driving connection between the parts results.

From the structure thus far described, it is seen that the rotary movement of the drive shaft 61 is transmitted through the collar 63 and disk 65 to the intermediate shaft 67 which in turn rotates the shaft 57 of one of the chill blocks 53 through the cones 71 and 73. The driven chill block 53'will of course drive the two adjacent chill blocks in View of the frictional contact therebetween and thus all of the chill blocks will rotate, with the alternate chill blocks traveling in the same direction as shown by the arrows; It is of course obvious that more than one motion transmitting means, consisting of a disk 65, shaft 67, and cones 71 and 73, may be employed so that a plurality of circumferentially spaced blocks 53 can be rotated by the central shaft 61. Further, the chill blocks 53 can be spaced relative to each other, circumferentially along the table 49, and be individually rotated by the central shaft 61 through a separate friction disk and cone arrangement asdescribed above. In this last-mentioned arrangement the shafts 67 may be alternately placed in vertically spaced relationship and be driven by one of a plurality of friction collar carried by the shaft 61. While the structure of Figure 4 has been described as having a friction drive means, it is of course obvious that gears may be employed in lieu of the friction transfer elements without departing from the spirit or scope of the invention.

Molten material is supplied to the .individualchill blocks 53 through the nozzles 74 removably mounted on the inclined surface 75 of the common ejection tube 77, which is continuously supplied with molten metal under pressure from a source, not shown. As heretofore described, a separate ejection tube may be employed with each of the chill blocks when desired or when necessary, as for example when filaments of different materials are being produced.

The operation of this embodiment of the invention is similar to those previously described, and it will be noted that with the arrangement shown in Figure 4, the streams of molten material are impinged against the individual chill blocks so that the finished filaments are all discharged outwardly away from the table 49. If it is desired to vary the physical characteristics of the filaments, the common ejection tube 77 may be rotated slightly about its vertical axis. In this manner, the streams of molten metal will impinge their respective chill blocks 53 at radial different points, with the points of impingement on certain alternate blocks moving nearer to the center, while the impact points on the remaining alternate blocks moving outwardly toward the periphery of the respective disks.

The apparatus shown in Figure 4 can be further modified by providing the chill surface of the blocks 53 and the top surface of the table 49, or only that portion of the table located outwardly of the chill blocks with a disk-shaped curvature so the individual chill surfaces together with the surface of the table 49 form a smooth continuous spherical concavity. In effect, the upper surface of the table 49 serves as a chill surface along with the individual chill surfaces of the blocks 53. In this case, a rotational speed of ten to thirty thousand r.p.m. is imparted to the table 49 by fixing the same to the shaft 61, which rotatably passes through the friction collar 63. Any suitable means, not shown, may be employed to maintain the collar 63 stationary. As the table 49 is rotated, the one or more friction disks 65 ride along the collar 63 and thereby transmit a rotary movement to the individual chill blocks 53. It is evident that with this arrangement, the combined movement of the table 49 and the chill blocks 53 impart a greater surface speed to those chill blocks 53 rotating in the same direction as the table 49 than would have been otherwise possible.

As the table 49 is rotated, the streams of molten metal ejected from the tube 77 will each consecutively impinge the chill surface of a block 5'3 rotating in the same direction as the table 49, then the surface of the table 49 between adjacent chill blocks 53, and then the chill surface of a block 53 rotating in a direction opposite to thatof the table'49. Thus, as the streams of molten metal each pass through their circular path, the surface speed at the different points of impingement will vary as the stream passes across each of the individual chill surfaces as well as when the streams pass onto and from the chill blocks and the surface of the table 49. Aside from this variation in the surface speeds at the points of impingement the operation of this modified structure is the same as heretofore described, and produces a mixture of metallic powders and discontinuous filaments. When the chill blocks 53 are disposed in spaced relation to all rotate in the same direction, as described above, it is evident that the rapid surface speeds which can be attained with this last-described apparatus permits the metal elements to be produced in a safer and more continuous manner and with a smaller chill surface than would normally be necessary.

The last illustrated embodiment of the present invention is designed along the lines of that shown in Figure 4-, and included a plurality of individual chill blocks '79 spaced circumferentially about a central drive shaft 81. The chill blocks 79 are similar in construction to blocks 53 and are supported for rotatable movement about their respective vertical axes on a table 82 similar to the table 49 shown in Figure 4. A plurality of friction segments E53 encircle the central drive shaft 81 and are resiliently urged against the peripheries of the chill blocks 79 for transmitting a rotary movement thereto. As with the chill blocks 53, the blocks 79 may also have their peripheries coated with a resilient material, such as rubber, the segments 83 each include a friction plate 85, which is removably mounted for purposes of repair or replacement, and guide pins 87 slidably disposed with a pair of openings 89 in the drive shaft 81 and constantly urged outwardly toward the chill block by springs 91. Thus, the combined action of the springs 91 and the centrifugal force developed by the segments 83 insure that a good driving contact exists between the friction segments 83 and the chill block peripheries. It will of course be understood that an alternate drive means, such as gears, can be substituted for the friction arrangement described without departing from the spirit and scope of the present invention. Alternately or in addition to the resilient mounted segments 83 the shafts of the re spective blocks 79 may be urged radially along suitable channels toward the drive shaft 81 to provide a good engagement between the chill blocks and central drive shaft. The nozzles 93 and ejection tube 95 for supplying streams of molten material to the chill blocks 79 and the manner of operation of this last-described embodiment are the same as described in relation to the structure in Figure 4. If desired, the table 832 may be provided with a spherical concavity and rotated along with the chill blocks 79 in a similar manner as described in relation to Figure 4.

As noted and described with examples in my above cited copending application, various ferrous and nonferrous metals, such as tin, lead cadmium, indium, zinc, bismuth, aluminum, magnesium, copper and their alloys and alloys of other metals may be employed in the making of the product described herein.

From the various embodiments of the invention de scribed above, it is seen that a plurality of filaments of the same or different materials can be simultaneously produced and may be collected either as an intermingled mass or as individual filaments. Further, in all forms of the invention, the cross-sectional configuration and the continuity of the filaments can be varied either as a unit, as shown in Figure 1, or individually as with the structure of Figures 2 and 3.

It is seen from the above description that the objects of the invention are well fulfilled by the structure and method described. The description is intended to be illustrative only and it is to be understood that changes and variations may be made without departing from the spirit and scope of the invention as defined by the appended claims.

I claim:

1. A device for continuously casting filaments comprising a table, means for rotating said table including a central drive shaft, a plurality of chill blocks rotatably mounted in said table, means for rotating said chill blocks with respect to said table and means for impinging at least one stream of molten metal at an angle against the surface formed by the chill blocks and table, said table and said plurality of chill blocks each having an open polished surface together forming a smooth continuous spherical concavity.

2. A device as set forth in claim 1 wherein said lastrnentioned means includes a single ejection tube having a plurality of nozzles through which said individual streams of molten material are adapted to flow.

3. A device as set forth in claim 1 wherein said chill blocks are disposed in arcuately spaced relationship.

4. A device according to claim 1 wherein said means for rotating the chill blocks includes a plurality of friction segments carried by the central drive shaft, the friction segments being in engagement with the peripheries of the chill blocks.

5. A device according to claim 4 wherein said friction segments are resiliently urged away from the central drive shaft into snug engagement with the chill block peripheries.

6. A device for continuously casting filaments comprising a table, means for rotating said table including a central drive shaft, a plurality of chill blocks rotatably mounted in said table, means for rotating said chill blocks with respect to said table and means for impinging at least one stream of molten metal at an angle against the surface formed by the chill blocks and table, said chill blocks being disposed with their edge peripheries in frictional contract, and said means for rotating said chill blocks including a friction collar fixed to said central drive shaft, a first friction cone fixed to at least one of said chill blocks, an intermediate shaft disposed between said friction collar and cone, a friction disk carried at one end of said intermediate shaft and adapted to engage with said collar, and a second friction cone on the opposite end of said intermediate shaft and adapted to engage with said first friction cone.

References Cited in the file of this patent UNITED STATES PATENTS 65,339 Butcher et al. June 4, 1867 690,884 Silvestri Jan. 7, 1902 989,075 Staples Apr. 11, 1911 1,063,895 Staples June 3, 1913 1,107,412 Davis Aug. 18, 1914 2,156,982 Harford et al. May 2, 1939 2,274,130 Davis Feb. 24, 1952 2,699,576 Colbry et al. Jan. 18, 1955 UNITED STATES PATENT OFFICE @ERTEFMATE 0F EORRECTIIQN Patent Noe 2310 744 November 3, 1959 Robert Bo Pond It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as cor erected belown In the grant lines 2 and 12, and in the heading to the printed. epeoifioatiom lines 4 and 5 name of aesignee, for "Marvaland, IZHGOIPOM- rated" each occurrence, read m Marvalaud, Incorporated w Signed and sealed this lOthday of May 19600 (SEAL) Attest:

FARLH" AXLINE ROBERT c, WATSON Attesting Officer Commissioner of Patents