US 3031717 A
Description (OCR text may contain errors)
May 1, 1962 M. LEVECQUE ETAL 3,031,717
CENTRIFUGAL FIBER FORMING APPARATUS Filed March 3, I958 INVENTORS MARCEL LEVECQUE PAUL PIOT ATTORNEY CENTRIFUGAL FIBER FGRMING APPARATUS Marcel Levecque, Saint-Gratien, and Paul Piot, Deuil,
France, assignors to Compagnie de Saint-Gobain, a corporation of France Filed Mar. 3, 1958, Ser. No. 718,654 Claims priority, application France Mar. 8, 1957 9 Ciaims. (Cl. 18--2.6)
The present invention relates to the manufacture of fibres from thermoplastic materials in the viscous state and particularly of glass fibres.
In this manufacture, it is known to use a hollow body into which the molten material is fed and the periphery of which is provided with orifices distributed in one or several rows. This hollow body being rotated at big. speed around its own axis, the material is projected by centrifugal force out of the orifices of the peripheral band in the form of streamlets which then undergo a drawing effect which transforms them into fibres.
It is also known to provide within, and co-axial with, the rotating body, a device shaped like a tank or trough of perforated side-walls into which the material is fed and serving to project said material onto the inside face of the peripheral band of the rotating body, and to distribute it evenly over the whole height of said band.
According to the present invention, the peripheral band and/ or the side wall of the distributing device is made of two elements in contact with each other, the outside element being made of a refractory material, and more particularly of a refractory alloy, ensuring good mechanical performance, and the internal element offering the maximum resistance to wear and permitting substantially constant feed conditions whatever may be the extent of wear of the external element.
In the present invention, the quantity of material projected through the openings of the peripheral band and/or of the distributing device is kept substantially constant during the life of said band or of said distributing device, the diameter of the openings which governs the feed conditions remaining constant and equal to the diameter suitable for giving themost favourable feed conditions.
In this connection it must be noted that the applicants have observed that, for an opening of 0.8 mm., a wear of the order of 0.1 mm. may bring about a feed increase of more than 50%.
According to an embodiment of the present invention, the external parts of the peripheral band and/ or of the wall of the distributing device are made of a refractory aloy whilst the internal parts are coated with a metal or alloy chemically resistant to glass at working temperature, such as platinum, platium-rhodium, tungsten, molybdenum or platinum-nickel.
The external and the internal part can be directly fitted one over the other, or fitted with interposition of a suitable intermediary material.
If desired, the openings of the internal parts may be of a diameter less than that of the openings of the external parts. Thus, the external parts of refractory alloy of the peripheral band can have openings of about 1 mm. diameter and the internal parts of glass-resistant alloy can have openings of about 0.5 to 0.6 mm. diameter. The internal parts may be thinner than the external parts.
In the annexed drawings showing, by way of example, a preferred embodiment of the invention:
FIG. 1 is a cross-section through the rotating body and its associated distributing device.
FIG. 2 is a section showing cylindrical orifices, and
FIG. 3 is a similar section showing tapering orifices.
Referring now to FIG. 1, 1 is the rotating body and 2 its associated distributing device. The peripheral band of the rotating body is made up of an external part 3 of tates Patent 3,031,717 IC Patented May 1, 1962 refractory material, preferably a refractory alloy, of good mechanical characteristics, and an internal part 4 of a wear-resistant material such as platinum or platinum-alloy. The diameter of the openings 5 of part 4 is inferior to that of the openings 6 of part 3 and it must be noted that the rate of projection of glass is determined by the size of openings 5.
The openings 6 may be cylindrical, as shown in FIG. 2, or tapering as shown in FIG. 3.
The distributing device 2 may be similarly constructed and comprises an external part 7 ensuring good mechanical behaviour and an internal wear-resistant part 8. The openings 9 and 10 provided in the internal part 8 and in the external part 7 respectively may be arranged as described above for the openings 5 and 6 of the peripheral band.
It must be understood that the present invention is not limited to the embodiment above described and illustrated which has been selected only by way of example.
What is claimed is:
1. Apparatus for producing fibers from molten thermoplastic viscous material including a centrifuging body having a peripheral wall provided with a plurality of projection orifices, said peripheral wall being formed of two elements in contact with each other, the external element being made of a refractory alloy, ensuring good mechanical performance, and the internal element offering the maximum resistance to wear in presence of the molten thermoplastic material, and with the orifices in the internal element having a smaller diameter than those in the external element so that the diameter of the orifices located in said elements remain practically unchanged over long periods of use.
2. An apparatus of the type set forth in claim 1 wherein the thickness of the external element is greater than the thickness of the internal element.
3. An apparatus of the type set forth in claim l where in the orifices in the internal element have a cylindrical shape while the orifices of the external element have a frusto conical shape.
4. An apparatus of the type set forth in claim 1 wherein the external and internal elements are directly fitted one over the other.
5. An apparatus of the type set forth in claim 1 wherein the external and internal elements are bonded one on the other.
6. An apparatus of the type set forth in claim 1 wherein the external and internal elements are bonded one on the other with a suitable material interposed between said elements.
7. An apparatus as set forth in claim 1 acting as a distributing organ in conjunction with a surrounding hollow centrifuge provided with a plurality of rows of orifices in the lateral wall thereof, said organ being located inside said last-mentioned centrifuge and spaced from said lastmentioned wall.
8. An apparatus according to claim 1 wherein the external element is a refractory alloy and the internal element is a metal of the group consisting of platinum, platinum-rhodium, tungsten, molybdenum, and platinumnickel.
9. Apparatus for producing fibers from a supply body of molten glass including an outer centrifuging body having a peripheral wall provided with a plurality of outlet orifices, said peripheral wall being formed of a refractory alloy resistant to heat, warpage and chemical attack, an internal element afiixed to the inside surface of the peripheral wall of the centrifuging body and provided with a series of orifices of smaller diameter than said orifices in said peripheral wall of the centrifuging body and in axial alignment therewith, said internal element offering maximum resistance to heat, chemical attack and wear in the presence of the molten glass, the refractory alloy constituting the peripheral wall of the centrifuging body next to the orifices of the internal element and therebetween serving to support and maintain the metal of the internal element against displacement and warpage in the presence of high temperature and the revolution of the peripheral wall of the outer centrifuging body and the internal element at high speeds.
References Cited in the file of this patent UNITED STATES PATENTS 1,592,140 Horton et al. July 13, 1926 2,031,083 Weller Feb. 18, 1936 2,133,236 Slayter et al Oct. 11, 1938 Richardson Feb. 13, 1940 Slayter et a1. Sept. 9, 1952 Heymes et a1; Jan. 13, 1953 Siefert et al Jan. 15, 1957 Kleist et a1 Aug. 23, 1960 FOREIGN PATENTS Australia Dec. 27, 1956 France Oct. 11, 1956 OTHER REFERENCES Glass Fibersf by De Dani, in Chemistry and Industry, pages 482-489, at pages 482 and 483, April 30, 1955 issue. Published by the Society of Chemical Industry, London,