| 摘要 |
A device (80) for sealing a furnace (50) which is used to draw a fiber (52) from a rod-like preform (51) includes a housing (82) having a cavity (121) for receiving a disc (111). The disc (111) is suspended for movement in the cavity in a plane lateral to the preform that extends through a center opening (116) in the disc and into the furnace. An inert gas is supplied to the cavity and directed inwardly through radially disposed passageways (118-118) in the disc (111) to impinge on the preform and split into two streams which move along the preform in opposite directions to prevent the entry of ambient air into, as well as the escape of gas from within, the furnace. The inert gas also causes the disc to be moved within the cavity to compensate for irregularities in the preform or for its misalignment from a vertical axis of the furnace, and provides a cushion so that contact between the disc and the preform is avoided.
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