US 3843762 A
Description (OCR text may contain errors)
PATENTEBUBI 22 m4 3.843762 SHED 1 0F 2 Fig. I
States Patent 11 1 1111 3,843,762 Sleigh 1 Oct. 22, 1974 METHOD OF MAKING FILAMENT 7,315 3/1910 (11.3111 1311111111 .1 164/87 0 45-5243 2 7) 1 1 .t 2 3  Inventor: Gordon Sleigh, 95 Meriton Rd., H9 Jlpm 164/ 8 Handforth, Wilmslow, England Primary Examiner-R. Spencer Annear  May 1973 Attorney, Agent, or Firm-Stephen L. Peterson ] Appl. No.: 365,083
52 11.5.0 264/213, 264/8, 264/215, 7 ABSTRACT 164/87 [64/283 M A method of insuring the spontaneous release of a fila-  Int. Cl. B22cl 13/00, DOld 5/00 58 M fs h 164/87 276 283 R 283 ment formed by contacting the surface of a molten 1 0 264i; 212 i material with the circumferential edge of a rotating heat-extracting member by applying a film of cooling References Cited to the external surface of the circumferential FOREIGN PATENTS OR APPLICATIONS 1961.957 9/1970 Germany 1. 164/278 6 Claims, 3 Drawing Figures METHOD OF MAKING FILAMENT BACKGROUND OF INVENTION The present invention relates to the art of making elongated filamentary articles by rotating a heatextracting member in contact with a source of molten material and solidifying a portion of the molten material as a filamentary product on the surface of the rotat' ing member where it spontaneously releases and is subsequently collected.
Prior art methods of producing filamentary articles conventionally comprise casting and repeated mechanical deformation techniques disposed to sequentially reduce the cross-sectional area of the elongated member. The complexity and cost of such operations have created along standing demand for amethod of forming filamentary material directly from the material in the molten state.
One proposed method involves the use of a rotating heat-extracting member in contact with the surface of a source of molten material. The member is shaped so as to limit the area introduced to the molten material and thereby solidify a filamentary article adherent thereto. The adherent filament is subsequently released from the forming member and is then collected. The spontaneous release of the previously adherent filamentary article is most important since the speed of operation and the size of the filament preclude the use of any scraping means to insure filament release. Furthermore, where the edge of the heat-extracting member is in contact with molten materials having high melting points (e.g., over 1,000 C) the resultant erosion and oxidation of the forming edge inhibits spontaneous release of the filament. While the use of internal circulation of cooling fluids within the member can reduce this effect the present invention substantially reduces the oxidation and erosion of the circumferential edge by applying an external film of cooling liquid to the edge.
SUMMARY OF THE INVENTION The present invention comprises the application of a liquid film to the external edge of a disk-like heatextracting member forming filamentary material by contacting the surface of a supply of molten material and solidifying a portion of that material on the circumferential edge of the heat-extracting member. Prior art techniques are hindered by the erosion or oxidation of this edge which effects the spontaneous release of the filaments formed thereon. In improving the cooling of the edge the present invention insures spontaneous release of the filament by preventing excessive heatbuildup at the edge and thereby preventing oxidation or erosion of the circumferential edge of the heatextracting member.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial cross section showing one embodiment of the present invention in side view.
FIG. 2 illustrates the embodiment of FIG. 1 rotated 90.
FIG. 3 is a cross-sectional view of the heatextracting member showing the operation of the present invention including the use of the internal coolant as the supply for the external cooling film.
2 DETAILED DESCRIPTION OF HE INVENTION The present invention is an improvement of a filament forming method operable with materials that, in
their molten state, have properties similar to those of I molten metals. Specifically the moltenmaterials operable with thepresent'invention must have (at a temperature within 25 percent of their equilibrium melting point in degrees Kelvin): a surface tension in the range of from to 2,500 dynes/cm, a viscosity in the range of from l0 to l poise and a reasonably discrete melting point (Le, a discontinuous viscosity versus temperature curve). Such molten materials are contacted on their surface by a rotating heat-extracting member generally in the manner shown in FIG. 1. I
The molten material 10 is contacted at thesurface 11 by the circumferential edge 32 of the rotating heatextracting member 30. In the embodimentshown the circumferential edge 32 is V-shaped with the apex of the V in contact with the melt surface 11. Byremoving heat from the molten material 10 a filamentary product is formed on the edge 32. The rotation of the member causes the edge 32 to be continuously advanced through the melt surface ll'as-well as promoting the spontaneous release of the filament 20 from the edge at the release point 35. y
The improvement of the process resides in the application of a cooling filmto the circumferential edge of the heat-extracting memberand the means shown in FIGS. 1 and 2 include a supporting member 40 containing a porous member 41 exposed to the application of a cooling liquid shown here simply as a tube 42 and a flow regulating valve 43; The porous member 41 isin contact with the circumferential edge 32 of the rotating member 30.
The embodiment shown in FIGS. 1 and 2 is in no way the only operable means of applying the cooling film. Other means would include the use of liquid sprays or aerosols, the direct application of the liquid to the edge etc. The inventive concept of the present invention is not the means used to apply the cooling film and one having ordinary skill in the art can readily devise means of dispensing and applying liquid to the edge using means not specifically described herein.
FIG. 3 illustrates an embodiment of the invention where the source of the cooling film is the liquid coolant circulating within the heat-extracting member. The member 30 is formed so as to allow a liquid coolant 50 to circulate internally so as to increase the capacity of the member 30 to remove heat from the molten material 10. The member 30 in this embodiment includes a porous section 38 that allows a portion of the internal coolant 50 to pass from the internal cavity onto the surface of the member 30 in the form of a cooling film. Furthermore, if the porosity of member were controlled to yield an appropriate flow rate of coolant to the surface the entire heat-extracting member may be porous.
The centrifugal force generated by the rotation of the heat-extracting member induces the flow of the film toward the circumferential edge 32 thereby placing the cooling film at the most critical location irrespective of the means used to place the film on the external surface of member 30. In this manner the edge 32 of the heatextracting member is further cooled and oxidation and erosion at that location are significantly inhibited. With the condition of the edge stabilized by the inhibition of oxidation and erosion the spontaneous release of the filament is insured.
The present invention may be used solely or in conjunction with intemal disk cooling and such a combination has been used successfully in preventing oxidation or erosion of a metal disk used to produce continuous filament from a source of molten steel. While continuous filament is specifically disclosed and illustrated in the figures the present invention is also applicable to a heat-extracting member having indentations on its circumferential edge of a depth greater than the diameter of the filament formed disposed to attenuatethe solidified filament into discontinuous filament having a length approximating the distance between indentations.
FIG. 3 also illustrates the configuration of the preferred embodiment of the circumferential edge 32. The member 30 has a thickness indicated as T and it preferably is in the range of from 0.10 to 2.0 inches. The radius R of the disk preferably is in the range of from 2 to inches and the radius of curvature r of the edge 32 is preferably in the range of from 0.0005 to 0.10 inch. The edge 32 is passed through the surface of the melt at a linear rate in excess of 3 ft/sec.
The liquid used as the coolant may be water or any liquid that does not chemically attach the molten material or the material comprising the disk. The coolant should be chemically unreactive with the atmosphere surrounding the process at the operating temperature and preferably be non-flammable.
1. In a method of forming filamentary material from a source of molten material havingproperties in the molten-state substantially similar to molten metals by rotating the circumferential edge of a disk-like heatextracting member in contact with the surface of said molten material while limiting the area'of contact of said edge with said surface, solidifying said material in solid filamentary form on said edge and spontaneously releasing the filament from said edge the improvement comprising:
applying a film of cooling liquid externally to said edge at a point between the location of spontaneous filament release and the point where said edge enters the surface of said molten material. I 2. The method of claim 1 where said disk-like heatextracting member is internally cooled by circulation of liquid therethrough with a portion of the internal cooling liquid passing through said member so as to form an external film of cooling liquid.
attenuate the filament into discontinuous lengths.