Containerless high purity pulling process and apparatus for glass fiber

摘要

Apparatus and method for pulling optical glass fibers in a containerless environment is disclosed which includes a single-axis acoustical levitation furnace (10) in which a specimen (S) is levitated and melted. A reflector unit (16) is carried in the interior of the furnace and includes a reflector (16a) disposed centrally about the acoustical axis of the levitator. The reflector unit includes a circular shroud (32) of insulation and a copper sleeve (34) inserted in the unit which is hollow at (34a) for receiving a cooling medium (38). A fiber pulling bore (40) is formed centrally in the reflector unit surrounded by cooling jacket (34a) to enhance solidification and formation of a fiber (F). A starting fiber strand is introduced into the melt and pulled outwardly through bore (40) whereby the specimen fiber is started and formed as pulled therethrough. In order to replenish the melt and thus enable a continuous process, a movable secondary reflector (42) is provided which captures a supplemental specimen pellet (46) and by movement of the reflector transfers it to the melt (S).