Patent ID: 9422185
Filing Date: 2016-08-23
CPC Classification: C03B,Y02P

Claim Text:
1. An apparatus for sintering a glass preform for an optical fiber, the glass preform for the optical fiber being received in a muffle tube and being heated in an atmospheric gas while being suspended on a shaft and supported thereon, comprising: a first gas seal that is provided at an upper end of the muffle tube, the shaft being inserted therethrough; a buffering chamber that is provided above the first gas seal and that covers the shaft; a second gas seal that is provided at an upper end of the buffering chamber, the shaft being inserted therethrough; an external air chamber adjacent to the buffering chamber and separated from the buffering chamber by the second gas seal; and a unit that introduces the atmospheric gas exhausted from the muffle tube into the buffering chamber, wherein the external air chamber comprises an atmosphere suction port that is provided to the external air chamber, and the external air chamber is always ventilated with external air.