| 摘要 |
665,802. Glass &c. fibres. ALGEMEENE KUNSTVEZEL MAATSCHAPPIJ N.V. Nov. 4, 1949 [Nov. 5, 1948], No. 28326/49. Class 56. Fibres are formed from plastic material such as glass, in the molten state, by causing streams of the molten material to flow into and be attenuated by a gaseous fluid under pressure in an expansion passage provided with at least one part in the form of a divergence of which the outlet forms the downflow end of the passage, the angle of divergence of the walls relative to the axis of the passage being less than 1 degree 30 minutes, and the ratio of the surface of the outlet and inlet of the divergence being less than 4. The crucible 1 lined with refractory material 2 and heated electrically has drawing orifices 3 at its lowest part and a cover 3 with an opening 5 through which glass &c. cullet or marbles is fed from pipe 6. The crucible is surrounded by a casing 8. The orifices 3 may be arranged in a circle and the expansion passage formed by a divergence 10 of circular section, as in Fig. 1, or arranged in straight rows and the expansion passage formed by a divergence of elongated rectangular section, as in Fig. 3. The gaseous fluid under pressure is introduced at 12 and expands in the divergence reducing the pressure at the neck 10a and assuming a high velocity which attenuates the filaments. The expansion passage may first converge and then diverge, and be of circular section, or, as in Fig. 6, of rectangular section at the upper end of the convergent and circular section at the lower end where it meets the divergence 10, see 16 in Figs. 5a, 6. The convergent preferably connects tangentially to the surface of the inlet of the divergence and to the face 11 of the casing 8. The crucible is heated through electrodes 17, 17a which have a fluid tight joint 21 with the casing. When the divergence is of elongated rectangular section the angle of divergence is preferably less than 1 degree and the ratio of the surfaces of the outlet and inlet less than 3. The space into which the divergence leads may be maintained at a pressure below atmospheric pressure.
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