Manufacturing apparatus and manufacturing method of porous glass base material for optical fiber

A porous glass base material manufacturing apparatus for an optical fiber comprising:

• a liquid mass flow controller for controlling a flow rate of a raw material liquid of an organic siloxane;
• a vaporizer for mixing the raw material liquid and a carrier gas to vaporize the raw material liquid to form a mixed gas in which a raw material gas and the carrier gas are mixed;
• a raw material liquid nozzle for ejecting the raw material liquid into the vaporizer;
• a carrier gas supply pipe for supplying the carrier gas into the vaporizer;
• a raw material liquid pipe for introducing the raw material liquid supplied from the liquid mass flow controller into the raw material liquid nozzle;
• a burner for combusting the mixed gas together with a combustible gas and a combustion supporting gas to produce SiO2 particles;
• a mixed gas pipe for supplying the mixed gas to the burner;
• an open/close valve provided on a flow path of the raw material liquid pipe;
• and
• a purge gas supply pipe that joins the raw material liquid pipe between the open/close valve and the raw material liquid nozzle to supply purge gas.