Patent GB-512700-A (GB)
Title: Process and apparatus for the continuous spinning of filaments and ribbons from quartz and other refractory oxides
IPC: C03B37/02
Filed: 1938-03-18
Abstract: 512,700. Fusing and working quartz; electric condensers; electric cables. SKAUPY, F., and WEISSENBERG, G. J. March 18, 1938, Nos. 8384, 8385, 8386, 8387 and 8388. Convention dates, March 18, 1937, April 27, 1937, April 27, 1937, July 26, 1937, and Oct. 12, 1937. [Class 56] [Also in Group XXXVI] Relates to a process for the continuous drawing of threads or ribbons of quartz, or other refractory oxides, in which the viscous material issues under pressure from an aperture or apertures in a heated container. According to the invention, the pressure to which the material is subjected, the temperature, and the rate of drawing are regulated in order to obtain threads of constant diameter. The threads so produced can be woven or knitted into fabrics, and they may be used for the insulating coverings of electric conductors, particularly when impregnated with organic insulating materials such as liquid ceresin or cellulose derivatives. Ribbons can be coated on one or both sides with metal, by means of a cathode sputtering process, for example, for use in electric condensers or for other purposes. The quartz may be fused in a receptacle 7 of refractory material, such as graphite, heated by high-frequency electric induction.. A tube 9 of refractory material, which dips into the fused quartz, has a bottom plate perforated with apertures 11. Part of the weight of the tube is balanced by weights 12, the remainder causing the tube to sink into the melt so that hydrostatic pressure forces the molten material through the apertures 11. At the beginning of a draw, a quartz plunger 14 attached to a spring 15 is used as a bait, and drawing is continued by a winding- drum 16. By adjusting the weights 12, the pressure on the material passing through the apertures 11 can be kept constant according to the speed of drawing. In another construction, the perforated base of a melting-receptacle is made 'of graphite, or other refractory material which is also an electric conductor, and serves as a resistance heater for fusing the superincumbent material. The fused material is extruded through the perforations by pressure, for example, by the weight of the material which is fed into the receptacle at a suitable rate to keep the quantity above the perforated plate constant. Preferably an inert gas, such as nitrogen, surrounds the fused material and the newly drawn threads; any other suitable furnace may be used to fuse the material. The drum on which the threads are wound is driven by an electric motor, and the speed of rotation may be varied automatically, in accordance with any alteration of the resistance of the heaters, to keep the diameter of the thread constant. Nitrogen, when used, may be employed to exert pressure on the melt to extrude the threads, and the pressure may be varied in accordance with the supply of electricity. The threads may be passed through a bath of electrolyte, as they are drawn, to discharge any static electricity. The Specification as open to inspection under Sect. 91 describes a construction in which the threads are drawn from a heated rod of quartz, threads of various cross-sections being obtained by suitably shaping the rods. Threads of larger diameter are formed into ribbons by rolling while the material is plastic, and hollow threads may be drawn. This subject-matter does not appear in the 'Specification as accepted.