| 摘要 |
PURPOSE:To enhance the efficiency of porous glass preform manufacturing work by attaching an on-off valve to an air pipe communicating with the exhaust pipe of the body of an apparatus for manufacturing a porous glass preform as a base material for an optical fiber and by setting an on-off valve driving device, a pressure change detector, a controller, etc. CONSTITUTION:Air pipe 15 communicating with exhaust pipe 11 of body 10 of an apparatus for manufacturing a porous glass preform as a base material for an optical fiber on the tip of a rodlike substrate with a burner is provided with on-off valve 16 for adjusting the internal pressure of pipe 11, driving device 27 for opening or closing valve 16, detector 17 for detecting a change in the internal pressure of pipe 11 and controller 24 which receives the detection signal of detector 17 and controls device 27. Thus, the internal pressure of pipe 11 is automaticaly held within a preset exhaust pressure range, and a flame blown off from the burner is prevented from flickering, giving a porous glass preform of uniform shape. |
