APPARATUS FOR PRODUCING OPTICAL FIBER PREFORM

PROBLEM TO BE SOLVED: To provide an apparatus for producing an optical fiber preform, suppressed in leakage of harmful gases and therefore showing improved safety.SOLUTION: The apparatus for producing an optical fiber preform is characterized by performing control during a non-steady operation under the control of a PLC (programmable logic controller) 15 in such a way that, when the count of an encoder 24 indicates that a muffle lid 23 is in the position where a muffle 17 is to be closed therewith and a proximity sensor 25 detects that the muffle lid 23 passes the position where the muffle 17 is to be closed therewith as a lifting device 14 lowers, the muffle 17 is decided to be closed with the muffle lid 23, while the feed of a gas into the muffle 17 is permitted, and the movement of a lifting device 14 is inhibited, whereas when the encoder 24 detects that the muffle lid 23 is outside the position where the muffle 17 is to be closed therewith and the proximity sensor 25 detects that the muffle lid 23 passes the position where the muffle 17 is to be closed therewith as the lifting device 14 rises, the muffle lid 23 is decided to be outside the position of stopping, while the feed of the gas is inhibited, and the movement of the lifting device 14 is permitted.