| 摘要 |
<p>The glass fiber (7) is drawn vertically up from the surface of the melt (2). It is drawn directly, using nothing which would constrict the vessel, such as nozzles. A temperature gradient is set up in the melt, such that its surface is at a lower temperature than its interior. The melt is contained in a ceramic crucible (1) resisting chemical attack from the melt. The crucible is alternatively carbon, preferably graphite. A noble metal, especially platinum or a platinum alloy, may be used instead. In order to set up a lower surface temperature, the surface of the melt is cooled by blowing it with a gas flow. Alternatively a cooled solid, especially made of metal, is located above the glass melt. The crucible may also be raised, so that the surface of the melt is no longer in the zone of constantly higher temperature. The glass fiber is wound up on a rotating drum above the glass melt. It is first led over one or more guidance rollers. Crucible and melt are heated in a resistance-heated furnace, or in an inductively-heated furnace (3, 4), where the current is coupled-in by a susceptor surrounding the crucible, or directly into the wall of a metal crucible. Current may alternatively be passed directly through the metal wall of the crucible. Glass is supplied continuously into the crucible for drawing, from a continuously-operating glass-melting tank. Glass or its raw materials are fed into the tank. At the start of the manufacturing process, an interceptor made of ceramic or precious metal, draws up the glass fiber from the glass surface in the crucible. A cooling zone is located between crucible and winding equipment. An independent claim IS INCLUDED FOR corresponding glass fiber drawing equipment.</p> |
