An optical fiber draw furnace system including a muffle, a downfeed handle, and a downfeed handle extension portion. The downfeed handle is moveably disposed within an inner cavity of the muffle. The downfeed handle extension portion is connected to the downfeed handle and moveably disposed within the inner cavity of the muffle. Furthermore, the downfeed handle extension portion forms a first gap between an outer surface of the downfeed handle extension portion and an inner surface of the muffle, the first gap having a length in a range of about 0.001 m to about 0.2 m.

A furnace gas supply apparatus configured to supply gas into a drawing furnace, includes: a first flow channel introducing the gas from a predetermined first gas inlet to flow the gas from a predetermined first gas outlet toward a gas storage portion, and a second flow channel introducing the gas stored in the gas storage portion from a predetermined second gas inlet to flow the gas from a predetermined second gas outlet toward a furnace core tube of the drawing furnace, in which the gas storage portion is provided between the first gas outlet and the second gas inlet, and in which an opening position of the second gas inlet is provided at a position different from an opening position of the first gas outlet.

An optical fiber draw furnace system including a muffle, a downfeed handle, and a downfeed handle extension portion. The downfeed handle is moveably disposed within an inner cavity of the muffle. The downfeed handle extension portion is connected to the downfeed handle and moveably disposed within the inner cavity of the muffle. Furthermore, the downfeed handle extension portion forms a first gap between an outer surface of the downfeed handle extension portion and an inner surface of the muffle, the first gap having a length in a range of about 0.001 m to about 0.2 m.